Sample records for future river flows
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Gibson, C.A.; Meyer, J.L.; Poff, N.L.; Hay, L.E.; Georgakakos, A.
2005-01-01
We examined impacts of future climate scenarios on flow regimes and how predicted changes might affect river ecosystems. We examined two case studies: Cle Elum River, Washington, and Chattahoochee-Apalachicola River Basin, Georgia and Florida. These rivers had available downscaled global circulation model (GCM) data and allowed us to analyse the effects of future climate scenarios on rivers with (1) different hydrographs, (2) high future water demands, and (3) a river-floodplain system. We compared observed flow regimes to those predicted under future climate scenarios to describe the extent and type of changes predicted to occur. Daily stream flow under future climate scenarios was created by either statistically downscaling GCMs (Cle Elum) or creating a regression model between climatological parameters predicted from GCMs and stream flow (Chattahoochee-Apalachicola). Flow regimes were examined for changes from current conditions with respect to ecologically relevant features including the magnitude and timing of minimum and maximum flows. The Cle Elum's hydrograph under future climate scenarios showed a dramatic shift in the timing of peak flows and lower low flow of a longer duration. These changes could mean higher summer water temperatures, lower summer dissolved oxygen, and reduced survival of larval fishes. The Chattahoochee-Apalachicola basin is heavily impacted by dams and water withdrawals for human consumption; therefore, we made comparisons between pre-large dam conditions, current conditions, current conditions with future demand, and future climate scenarios with future demand to separate climate change effects and other anthropogenic impacts. Dam construction, future climate, and future demand decreased the flow variability of the river. In addition, minimum flows were lower under future climate scenarios. These changes could decrease the connectivity of the channel and the floodplain, decrease habitat availability, and potentially lower the ability of the river to assimilate wastewater treatment plant effluent. Our study illustrates the types of changes that river ecosystems might experience under future climates. Copyright ?? 2005 John Wiley & Sons, Ltd.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Yang, Zhaoqing; Wang, Taiping; Voisin, Nathalie
Understanding the response of river flow and estuarine hydrodynamics to climate change, land-use/land-cover change (LULC), and sea-level rise is essential to managing water resources and stress on living organisms under these changing conditions. This paper presents a modeling study using a watershed hydrology model and an estuarine hydrodynamic model, in a one-way coupling, to investigate the estuarine hydrodynamic response to sea-level rise and change in river flow due to the effect of future climate and LULC changes in the Snohomish River estuary, Washington, USA. A set of hydrodynamic variables, including salinity intrusion points, average water depth, and salinity of themore » inundated area, were used to quantify the estuarine response to river flow and sea-level rise. Model results suggest that salinity intrusion points in the Snohomish River estuary and the average salinity of the inundated areas are a nonlinear function of river flow, although the average water depth in the inundated area is approximately linear with river flow. Future climate changes will shift salinity intrusion points further upstream under low flow conditions and further downstream under high flow conditions. In contrast, under the future LULC change scenario, the salinity intrusion point will shift downstream under both low and high flow conditions, compared to present conditions. The model results also suggest that the average water depth in the inundated areas increases linearly with sea-level rise but at a slower rate, and the average salinity in the inundated areas increases linearly with sea-level rise; however, the response of salinity intrusion points in the river to sea-level rise is strongly nonlinear.« less
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Regulation of snow-fed rivers affects flow regimes more than climate change.
Arheimer, B; Donnelly, C; Lindström, G
2017-07-05
River flow is mainly controlled by climate, physiography and regulations, but their relative importance over large landmasses is poorly understood. Here we show from computational modelling that hydropower regulation is a key driver of flow regime change in snow-dominated regions and is more important than future climate changes. This implies that climate adaptation needs to include regulation schemes. The natural river regime in snowy regions has low flow when snow is stored and a pronounced peak flow when snow is melting. Global warming and hydropower regulation change this temporal pattern similarly, causing less difference in river flow between seasons. We conclude that in snow-fed rivers globally, the future climate change impact on flow regime is minor compared to regulation downstream of large reservoirs, and of similar magnitude over large landmasses. Our study not only highlights the impact of hydropower production but also that river regulation could be turned into a measure for climate adaptation to maintain biodiversity on floodplains under climate change.Global warming and hydropower regulations are major threats to future fresh-water availability and biodiversity. Here, the authors show that their impact on flow regime over a large landmass result in similar changes, but hydropower is more critical locally and may have potential for climate adaptation in floodplains.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Werth, D.; Chen, K. F.
2013-08-22
The ability of water managers to maintain adequate supplies in coming decades depends, in part, on future weather conditions, as climate change has the potential to alter river flows from their current values, possibly rendering them unable to meet demand. Reliable climate projections are therefore critical to predicting the future water supply for the United States. These projections cannot be provided solely by global climate models (GCMs), however, as their resolution is too coarse to resolve the small-scale climate changes that can affect hydrology, and hence water supply, at regional to local scales. A process is needed to ‘downscale’ themore » GCM results to the smaller scales and feed this into a surface hydrology model to help determine the ability of rivers to provide adequate flow to meet future needs. We apply a statistical downscaling to GCM projections of precipitation and temperature through the use of a scaling method. This technique involves the correction of the cumulative distribution functions (CDFs) of the GCM-derived temperature and precipitation results for the 20{sup th} century, and the application of the same correction to 21{sup st} century GCM projections. This is done for three meteorological stations located within the Coosa River basin in northern Georgia, and is used to calculate future river flow statistics for the upper Coosa River. Results are compared to the historical Coosa River flow upstream from Georgia Power Company’s Hammond coal-fired power plant and to flows calculated with the original, unscaled GCM results to determine the impact of potential changes in meteorology on future flows.« less
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NASA Astrophysics Data System (ADS)
Prudhomme, C.; Haxton, T.; Crooks, S.; Jackson, C.; Barkwith, A.; Williamson, J.; Kelvin, J.; Mackay, J.; Wang, L.; Young, A.; Watts, G.
2012-12-01
The dataset Future Flows Hydrology was developed as part of the project "Future Flows and Groundwater Levels" to provide a consistent set of transient daily river flow and monthly groundwater levels projections across England, Wales and Scotland to enable the investigation of the role of climate variability on river flow and groundwater levels nationally and how this may change in the future. Future Flows Hydrology is derived from Future Flows Climate, a national ensemble projection derived from the Hadley Centre's ensemble projection HadRM3-PPE to provide a consistent set of climate change projections for the whole of Great Britain at both space and time resolutions appropriate for hydrological applications. Three hydrological models and one groundwater level model were used to derive Future Flows Hydrology, with 30 river sites simulated by two hydrological models to enable assessment of hydrological modelling uncertainty in studying the impact of climate change on the hydrology. Future Flows Hydrology contains an 11-member ensemble of transient projections from January 1951 to December 2098, each associated with a single realisation from a different variant of HadRM3 and a single hydrological model. Daily river flows are provided for 281 river catchments and monthly groundwater levels at 24 boreholes as .csv files containing all 11 ensemble members. When separate simulations are done with two hydrological models, two separate .csv files are provided. Because of potential biases in the climate-hydrology modelling chain, catchment fact sheets are associated with each ensemble. These contain information on the uncertainty associated with the hydrological modelling when driven using observed climate and Future Flows Climate for a period representative of the reference time slice 1961-1990 as described by key hydrological statistics. Graphs of projected changes for selected hydrological indicators are also provided for the 2050s time slice. Limitations associated with the dataset are provided, along with practical recommendation of use. Future Flows Hydrology is freely available for non-commercial use under certain licensing conditions. For each study site, catchment averages of daily precipitation and monthly potential evapotranspiration, used to drive the hydrological models, are made available, so that hydrological modelling uncertainty under climate change conditions can be explored further. doi:10.5285/f3723162-4fed-4d9d-92c6-dd17412fa37b.
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NASA Astrophysics Data System (ADS)
Prudhomme, C.; Haxton, T.; Crooks, S.; Jackson, C.; Barkwith, A.; Williamson, J.; Kelvin, J.; Mackay, J.; Wang, L.; Young, A.; Watts, G.
2013-03-01
The dataset Future Flows Hydrology was developed as part of the project "Future Flows and Groundwater Levels'' to provide a consistent set of transient daily river flow and monthly groundwater level projections across England, Wales and Scotland to enable the investigation of the role of climate variability on river flow and groundwater levels nationally and how this may change in the future. Future Flows Hydrology is derived from Future Flows Climate, a national ensemble projection derived from the Hadley Centre's ensemble projection HadRM3-PPE to provide a consistent set of climate change projections for the whole of Great Britain at both space and time resolutions appropriate for hydrological applications. Three hydrological models and one groundwater level model were used to derive Future Flows Hydrology, with 30 river sites simulated by two hydrological models to enable assessment of hydrological modelling uncertainty in studying the impact of climate change on the hydrology. Future Flows Hydrology contains an 11-member ensemble of transient projections from January 1951 to December 2098, each associated with a single realisation from a different variant of HadRM3 and a single hydrological model. Daily river flows are provided for 281 river catchments and monthly groundwater levels at 24 boreholes as .csv files containing all 11 ensemble members. When separate simulations are done with two hydrological models, two separate .csv files are provided. Because of potential biases in the climate-hydrology modelling chain, catchment fact sheets are associated with each ensemble. These contain information on the uncertainty associated with the hydrological modelling when driven using observed climate and Future Flows Climate for a period representative of the reference time slice 1961-1990 as described by key hydrological statistics. Graphs of projected changes for selected hydrological indicators are also provided for the 2050s time slice. Limitations associated with the dataset are provided, along with practical recommendation of use. Future Flows Hydrology is freely available for non-commercial use under certain licensing conditions. For each study site, catchment averages of daily precipitation and monthly potential evapotranspiration, used to drive the hydrological models, are made available, so that hydrological modelling uncertainty under climate change conditions can be explored further. doi:10.5285/f3723162-4fed-4d9d-92c6-dd17412fa37b
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Ege, John R.; ,
1983-01-01
Procedures for reducing hazards from future lahars and debris flows in the Krasak River channel near Yogyakarta, Central Java, Indonesia, include (1) determining the history of the location, size, and effects of previous lahars and debris flows, and (2) decreasing flow velocities. The first may be accomplished by geologic field mapping along with acquiring information by interviewing local residents, and the second by increasing the cross sectional area of the river channel and constructing barriers in the flow path.
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Improving estuary models by reducing uncertainties associated with river flows
NASA Astrophysics Data System (ADS)
Robins, Peter E.; Lewis, Matt J.; Freer, Jim; Cooper, David M.; Skinner, Christopher J.; Coulthard, Tom J.
2018-07-01
To mitigate against future changes to estuaries such as water quality, catchment and estuary models can be coupled to simulate the transport of harmful pathogenic viruses, pollutants and nutrients from their terrestrial sources, through the estuary and to the coast. To predict future changes to estuaries, daily mean river flow projections are typically used. We show that this approach cannot resolve higher frequency discharge events that have large impacts to estuarine dilution, contamination and recovery for two contrasting estuaries. We therefore characterise sub-daily scale flow variability and propagate this through an estuary model to provide robust estimates of impacts for the future. River flow data (35-year records at 15-min sampling) were used to characterise variabilities in storm hydrograph shapes and simulate the estuarine response. In particular, we modelled a fast-responding catchment-estuary system (Conwy, UK), where the natural variability in hydrograph shapes generated large variability in estuarine circulation that was not captured when using daily-averaged river forcing. In the extreme, the freshwater plume from a 'flash' flood (lasting <12 h) was underestimated by up to 100% - and the response to nutrient loading was underestimated further still. A model of a slower-responding system (Humber, UK), where hydrographs typically last 2-4 days, showed less variability in estuarine circulation and good approximation with daily-averaged flow forcing. Our result has implications for entire system impact modelling; when we determine future changes to estuaries, some systems will need higher resolution future river flow estimates.
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NASA Astrophysics Data System (ADS)
Fung, C. F.; Lopez, A.; New, M.
2009-04-01
Climate change is likely to impact on freshwater ecology, the delivery of regulatory commitments to ecological status and the management of water resources. It is becoming increasingly important for European environment agencies to use and develop methods to aid planning and abstraction licensing procedures and policies in the face of climate change and with the introduction of the Water Framework Directive. Studies have been carried out in the past to investigate the implications of climate change for biodiversity. However, predicting the future is fraught with uncertainty, an area which has not been dealt with in great depth in the past. This study has been undertaken to draw on the results of new methodologies to address the uncertainties inherent in modelling future climate and assess their usability for decision-making in water resources allocations specifically in considering interactions between flow and invertebrate communities The River Itchen was chosen as the case study catchment on the strength of having a long-term coupled ecological and flow dataset and having been an area of intensive study in the past. It is a chalk stream located in the south of England and a candidate Special Area of Conservation. It has also been designated a Special Site of Scientific Interest achieved due to the number of rare species, and the richness of the macro-invertebrate community in the river catchment. An ensemble of 246 transient simulations for future climate was obtained from ClimatePrediction.net which were then used to drive a rainfall-runoff model. In order to link the modelled river flow to ecology, the Lotic Invertebrate Flow Evaluation score has been used where the invertebrate community is linked to flow largely through sensitivity to water velocity and siltation, driven by flow variability at sites with fixed channel dimensions The large ensemble of climate scenarios and thereby flow and ecological indices allows the exploration of the risk of the river of not meeting environmental flow targets in the future. Three sets of environmental flow targets which were drawn up by the Environment Agency for England and Wales for the River Itchen were tested and show that it may be difficult to maintain a natural chalk stream invertebrate community in the River Itchen in the future. The ensemble also shows low flows regularly extending from August to December which could result in the loss of a high proportion of individuals recruited that year. This would in turn lead to diminished over-wintering populations, with potentially catastrophic consequences for the following years breeding and recruitment programme. Due to a paucity of quantitative data for the response of macroinvertebrates to multi-year droughts, to provide a richer story, a matrix has been proposed for analysing the effects on biodiversity of the river which combines both the thresholds derived previously and expert opinion on how the ecology of the River Itchen will react to climate change. The matrices also provide a more accessible way of communicating rather complex information to a wider community of decision-makers. Should large changes in flow arise in the future it is likely that some form of action will be taken to mitigate or adapt to the impacts of climate change. Maintaining the ecological status of the river throug river support, i.e. augmenting river flow by pumping from the groundwater aquifer, has also been investigated. However, by augmenting the flow, the high flows are also reduced which can be important for scouring the river bed and removing silt to the benefit of the invertebrate community. Therefore at some point further augmentation may need to be curtailed in order to maintain high flows.
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The importance of base flow in sustaining surface water flow in the Upper Colorado River Basin
Miller, Matthew P.; Buto, Susan G.; Susong, David D.; Rumsey, Christine
2016-01-01
The Colorado River has been identified as the most overallocated river in the world. Considering predicted future imbalances between water supply and demand and the growing recognition that base flow (a proxy for groundwater discharge to streams) is critical for sustaining flow in streams and rivers, there is a need to develop methods to better quantify present-day base flow across large regions. We adapted and applied the spatially referenced regression on watershed attributes (SPARROW) water quality model to assess the spatial distribution of base flow, the fraction of streamflow supported by base flow, and estimates of and potential processes contributing to the amount of base flow that is lost during in-stream transport in the Upper Colorado River Basin (UCRB). On average, 56% of the streamflow in the UCRB originated as base flow, and precipitation was identified as the dominant driver of spatial variability in base flow at the scale of the UCRB, with the majority of base flow discharge to streams occurring in upper elevation watersheds. The model estimates an average of 1.8 × 1010 m3/yr of base flow in the UCRB; greater than 80% of which is lost during in-stream transport to the Lower Colorado River Basin via processes including evapotranspiration and water diversion for irrigation. Our results indicate that surface waters in the Colorado River Basin are dependent on base flow, and that management approaches that consider groundwater and surface water as a joint resource will be needed to effectively manage current and future water resources in the Basin.
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The importance of base flow in sustaining surface water flow in the Upper Colorado River Basin
NASA Astrophysics Data System (ADS)
Miller, Matthew P.; Buto, Susan G.; Susong, David D.; Rumsey, Christine A.
2016-05-01
The Colorado River has been identified as the most overallocated river in the world. Considering predicted future imbalances between water supply and demand and the growing recognition that base flow (a proxy for groundwater discharge to streams) is critical for sustaining flow in streams and rivers, there is a need to develop methods to better quantify present-day base flow across large regions. We adapted and applied the spatially referenced regression on watershed attributes (SPARROW) water quality model to assess the spatial distribution of base flow, the fraction of streamflow supported by base flow, and estimates of and potential processes contributing to the amount of base flow that is lost during in-stream transport in the Upper Colorado River Basin (UCRB). On average, 56% of the streamflow in the UCRB originated as base flow, and precipitation was identified as the dominant driver of spatial variability in base flow at the scale of the UCRB, with the majority of base flow discharge to streams occurring in upper elevation watersheds. The model estimates an average of 1.8 × 1010 m3/yr of base flow in the UCRB; greater than 80% of which is lost during in-stream transport to the Lower Colorado River Basin via processes including evapotranspiration and water diversion for irrigation. Our results indicate that surface waters in the Colorado River Basin are dependent on base flow, and that management approaches that consider groundwater and surface water as a joint resource will be needed to effectively manage current and future water resources in the Basin.
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Jin, Li; Whitehead, Paul G; Rodda, Harvey; Macadam, Ian; Sarkar, Sananda
2018-10-01
Delta systems formed by the deposition of sediments at the mouths of large catchments are vulnerable to sea level rise and other climate change impacts. Deltas often have some of the highest population densities in the world and the Mahanadi Delta in India is one of these, with a population of 39 million. The Mahanadi River is a major river in East Central India and flows through Chattisgarh and Orissa states before discharging into the Bay of Bengal. This study uses an Integrated Catchment Model (INCA) to simulate flow dynamics and water quality (nitrogen and phosphorus) and to analyze the impacts of climate change and socio-economic drivers in the Mahanadi River system. Future flows affected by large population growth, effluent discharge increases and changes in irrigation water demand from changing land uses are assessed under shared socio-economic pathways (SSPs). Model results indicate a significant increase in monsoon flows under the future climates at 2050s (2041-2060) and 2090s (2079-2098) which greatly enhances flood potential. The water availability under low flow conditions will be worsened because of increased water demand from population growth and increased irrigation in the future. Decreased concentrations of nitrogen and phosphorus are expected due to increased flow hence dilution. Socio-economic scenarios have a significant impact on water quality but less impact on the river flow. For example, higher population growth, increased sewage treatment discharges, land use change and enhanced atmospheric deposition would result in the deterioration of water quality, while the upgrade of the sewage treatment works lead to improved water quality. In summary, socio-economic scenarios would change future water quality of the Mahanadi River and alter nutrient fluxes transported into the delta region. This study has serious implications for people's livelihoods in the deltaic area and could impact coastal and Bay of Bengal water ecology. Copyright © 2018 Elsevier B.V. All rights reserved.
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South Asia river flow projections and their implications for water resources
NASA Astrophysics Data System (ADS)
Mathison, C.; Wiltshire, A. J.; Falloon, P.; Challinor, A. J.
2015-06-01
South Asia is a region with a large and rising population and a high dependance on industries sensitive to water resource such as agriculture. The climate is hugely variable with the region relying on both the Asian Summer Monsoon (ASM) and glaciers for its supply of fresh water. In recent years, changes in the ASM, fears over the rapid retreat of glaciers and the increasing demand for water resources for domestic and industrial use, have caused concern over the reliability of water resources both in the present day and future for this region. The climate of South Asia means it is one of the most irrigated agricultural regions in the world, therefore pressures on water resource affecting the availability of water for irrigation could adversely affect crop yields and therefore food production. In this paper we present the first 25 km resolution regional climate projections of river flow for the South Asia region. ERA-Interim, together with two global climate models (GCMs), which represent the present day processes, particularly the monsoon, reasonably well are downscaled using a regional climate model (RCM) for the periods; 1990-2006 for ERA-Interim and 1960-2100 for the two GCMs. The RCM river flow is routed using a river-routing model to allow analysis of present day and future river flows through comparison with river gauge observations, where available. In this analysis we compare the river flow rate for 12 gauges selected to represent the largest river basins for this region; Ganges, Indus and Brahmaputra basins and characterize the changing conditions from east to west across the Himalayan arc. Observations of precipitation and runoff in this region have large or unknown uncertainties, are short in length or are outside the simulation period, hindering model development and validation designed to improve understanding of the water cycle for this region. In the absence of robust observations for South Asia, a downscaled ERA-Interim RCM simulation provides a benchmark for comparison against the downscaled GCMs. On the basis that these simulations are among the highest resolution climate simulations available we examine how useful they are for understanding the changes in water resources for the South Asia region. In general the downscaled GCMs capture the seasonality of the river flows, with timing of maximum river flows broadly matching the available observations and the downscaled ERA-Interim simulation. Typically the RCM simulations over-estimate the maximum river flows compared to the observations probably due to a positive rainfall bias and a lack of abstraction in the model although comparison with the downscaled ERA-Interim simulation is more mixed with only a couple of the gauges showing a bias compared with the downscaled GCM runs. The simulations suggest an increasing trend in annual mean river flows for some of the river gauges in this analysis, in some cases almost doubling by the end of the century; this trend is generally masked by the large annual variability of river flows for this region. The future seasonality of river flows does not change with the future maximum river flow rates still occuring during the ASM period, with a magnitude in some cases, greater than the present day natural variability. Increases in river flow during peak flow periods means additional water resource for irrigation, the largest usage of water in this region, but also has implications in terms of inundation risk. Low flow rates also increase which is likely to be important at times of the year when water is historically more scarce. However these projected increases in resource from rivers could be more than countered by changes in demand due to reductions in the quantity and quality of water available from groundwater, increases in domestic use due to a rising population or expansion of other industries such as hydro-electric power generation.
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Whitehead, P G; Barbour, E; Futter, M N; Sarkar, S; Rodda, H; Caesar, J; Butterfield, D; Jin, L; Sinha, R; Nicholls, R; Salehin, M
2015-06-01
The potential impacts of climate change and socio-economic change on flow and water quality in rivers worldwide is a key area of interest. The Ganges-Brahmaputra-Meghna (GBM) is one of the largest river basins in the world serving a population of over 650 million, and is of vital concern to India and Bangladesh as it provides fresh water for people, agriculture, industry, conservation and for the delta system downstream. This paper seeks to assess future changes in flow and water quality utilising a modelling approach as a means of assessment in a very complex system. The INCA-N model has been applied to the Ganges, Brahmaputra and Meghna river systems to simulate flow and water quality along the rivers under a range of future climate conditions. Three model realisations of the Met Office Hadley Centre global and regional climate models were selected from 17 perturbed model runs to evaluate a range of potential futures in climate. In addition, the models have also been evaluated using socio-economic scenarios, comprising (1) a business as usual future, (2) a more sustainable future, and (3) a less sustainable future. Model results for the 2050s and the 2090s indicate a significant increase in monsoon flows under the future climates, with enhanced flood potential. Low flows are predicted to fall with extended drought periods, which could have impacts on water and sediment supply, irrigated agriculture and saline intrusion. In contrast, the socio-economic changes had relatively little impact on flows, except under the low flow regimes where increased irrigation could further reduce water availability. However, should large scale water transfers upstream of Bangladesh be constructed, these have the potential to reduce flows and divert water away from the delta region depending on the volume and timing of the transfers. This could have significant implications for the delta in terms of saline intrusion, water supply, agriculture and maintaining crucial ecosystems such as the mangrove forests, with serious implications for people's livelihoods in the area. The socio-economic scenarios have a significant impact on water quality, altering nutrient fluxes being transported into the delta region.
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Future Climate Change Impact Assessment of River Flows at Two Watersheds of Peninsular Malaysia
NASA Astrophysics Data System (ADS)
Ercan, A.; Ishida, K.; Kavvas, M. L.; Chen, Z. R.; Jang, S.; Amin, M. Z. M.; Shaaban, A. J.
2016-12-01
Impacts of climate change on the river flows under future climate change conditions were assessed over Muda and Dungun watersheds of Peninsular Malaysia by means of a coupled regional climate model and a physically-based hydrology model utilizing an ensemble of 15 different future climate realizations. Coarse resolution GCMs' future projections covering a wide range of emission scenarios were dynamically downscaled to 6 km resolution over the study area. Hydrologic simulations of the two selected watersheds were carried out at hillslope-scale and at hourly increments.
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NASA Astrophysics Data System (ADS)
Hoang, L. P.; van Vliet, M. T. H.; Lauri, H.; Kummu, M.; Koponen, J.; Supit, I.; Leemans, R.; Kabat, P.; Ludwig, F.
2016-12-01
The Mekong River's flows and water resources are in many ways essential for sustaining economic growths, flood security of about 70 million people and biodiversity in one of the world's most ecologically productive wetland systems. The river's hydrological cycle, however, are increasingly perturbed by climate change, large-scale hydropower developments and rapid irrigated land expansions. This study presents an integrated impact assessment to characterize and quantify future hydrological changes induced by these driving factors, both separately and combined. We have integrated a crop simulation module and a hydropower dam module into a distributed hydrological model (VMod) and simulated the Mekong's hydrology under multiple climate change and development scenarios. Our results show that the Mekong's hydrological regime will experience substantial changes caused by the considered factors. Magnitude-wise, hydropower dam developments exhibit the largest impacts on river flows, with projected higher flows (up to +35%) during the dry season and lower flows (up to -44%) during the wet season. Annual flow changes caused by the dams, however, are relatively marginal. In contrast to this, climate change is projected to increase the Mekong's annual flows (up to +16%) while irrigated land expansions result in annual flow reductions (-1% to -3%). Combining the impacts of these three drivers, we found that river flow changes, especially those at the monthly scale, largely differ from changes under the individual driving factors. This is explained by large differences in impacts' magnitudes and contrasting impacts' directions for the individual drivers. We argue that the Mekong's future flows are likely driven by multiple factors and thus advocate for integrated assessment approaches and tools that support proper considerations of these factors and their interplays.
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Sensitivity of Circulation in the Skagit River Estuary to Sea Level Rise and Future Flows
DOE Office of Scientific and Technical Information (OSTI.GOV)
Khangaonkar, Tarang; Long, Wen; Sackmann, Brandon
Future climate simulations based on the Intergovernmental Panel on Climate Change emissions scenario (A1B) have shown that the Skagit River flow will be affected, which may lead to modification of the estuarine hydrodynamics. There is considerable uncertainty, however, about the extent and magnitude of resulting change, given accompanying sea level rise and site-specific complexities with multiple interconnected basins. To help quantify the future hydrodynamic response, we developed a three dimensional model of the Skagit River estuary using the Finite Volume Coastal Ocean Model (FVCOM). The model was set up with localized high-resolution grids in Skagit and Padilla Bay sub-basins withinmore » the intermediate-scale FVCOM based model of the Salish Sea (greater Puget Sound and Georgia Basin). Future changes to salinity and annual transport through the basin were examined. The results confirmed the existence of a residual estuarine flow that enters Skagit Bay from Saratoga Passage to the south and exits through Deception Pass. Freshwater from the Skagit River is transported out in the surface layers primarily through Deception Pass and Saratoga Passage, and only a small fraction (≈4%) is transported to Padilla Bay. The moderate future perturbations of A1B emissions, corresponding river flow, and sea level rise of 0.48 m examined here result only in small incremental changes to salinity structure and inter-basin freshwater distribution and transport. An increase in salinity of ~1 ppt in the near-shore environment and a salinity intrusion of approximately 3 km further upstream is predicted in Skagit River, well downstream of the drinking water intakes.« less
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Classification of reaches in the Missouri and lower Yellowstone Rivers based on flow characteristics
Pegg, Mark A.; Pierce, Clay L.
2002-01-01
Several aspects of flow have been shown to be important determinants of biological community structure and function in streams, yet direct application of this approach to large rivers has been limited. Using a multivariate approach, we grouped flow gauges into hydrologically similar units in the Missouri and lower Yellowstone Rivers and developed a model based on flow variability parameters that could be used to test hypotheses about the role of flow in determining aquatic community structure. This model could also be used for future comparisons as the hydrological regime changes. A suite of hydrological parameters for the recent, post-impoundment period (1 October 1966–30 September 1996) for each of 15 gauges along the Missouri and lower Yellowstone Rivers were initially used. Preliminary graphical exploration identified five variables for use in further multivariate analyses. Six hydrologically distinct units composed of gauges exhibiting similar flow characteristics were then identified using cluster analysis. Discriminant analyses identified the three most influential variables as flow per unit drainage area, coefficient of variation of mean annual flow, and flow constancy. One surprising result was the relative similarity of flow regimes between the two uppermost and three lowermost gauges, despite large differences in magnitude of flow and separation by roughly 3000 km. Our results synthesize, simplify and interpret the complex changes in flow occurring along the Missouri and lower Yellowstone Rivers, and provide an objective grouping for future tests of how these changes may affect biological communities.
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Climate change enhances interannual variability of the Nile river flow
NASA Astrophysics Data System (ADS)
Siam, Mohamed S.; Eltahir, Elfatih A. B.
2017-04-01
The human population living in the Nile basin countries is projected to double by 2050, approaching one billion. The increase in water demand associated with this burgeoning population will put significant stress on the available water resources. Potential changes in the flow of the Nile River as a result of climate change may further strain this critical situation. Here, we present empirical evidence from observations and consistent projections from climate model simulations suggesting that the standard deviation describing interannual variability of total Nile flow could increase by 50% (+/-35%) (multi-model ensemble mean +/- 1 standard deviation) in the twenty-first century compared to the twentieth century. We attribute the relatively large change in interannual variability of the Nile flow to projected increases in future occurrences of El Niño and La Niña events and to observed teleconnection between the El Niño-Southern Oscillation and Nile River flow. Adequacy of current water storage capacity and plans for additional storage capacity in the basin will need to be re-evaluated given the projected enhancement of interannual variability in the future flow of the Nile river.
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Development of a new IHA method for impact assessment of climate change on flow regime
NASA Astrophysics Data System (ADS)
Yang, Tao; Cui, Tong; Xu, Chong-Yu; Ciais, Philippe; Shi, Pengfei
2017-09-01
The Indicators of Hydrologic Alteration (IHA) based on 33 parameters in five dimensions (flow magnitude, timing, duration, frequency and change rate) have been widely used in evaluation of hydrologic alteration in river systems. Yet, inter-correlation seriously exists amongst those parameters, therefore constantly underestimates or overestimates actual hydrological changes. Toward the end, a new method (Representative-IHA, RIHA) is developed by removing repetitions based on Criteria Importance Through Intercriteria Correlation (CRITIC) algorithm. RIHA is testified in evaluating effects of future climate change on hydro-ecology in the Niger River of Africa. Future flows are projected using three watershed hydrological models forced by five general circulation models (GCMs) under three Representative Concentration Pathways (RCPs) scenarios. Results show that: (1) RIHA is able to eliminate self-correlations amongst IHA indicators and identify the dominant characteristics of hydrological alteration in the Upper Niger River, (2) March streamflow, September streamflow, December streamflow, 30-day annual maximum, low pluses duration and fall rates tends to increase over the period 2010-2099, while July streamflow and 90-day annual minimum streamflow shows decrease, (3) the Niger River will undergo moderate flow alteration under RCP8.5 in 2050s and 2080s and low alteration other scenarios, (4) future flow alteration may induce increase water temperatures, reduction dissolved oxygen and food resources. Consequently, aquatic biodiversity and fish community of Upper Niger River would become more vulnerable in the future. The new method enables more scientific evaluation for multi-dimensional hydrologic alteration under the context of climate change.
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The twenty-first century Colorado River hot drought and implications for the future
NASA Astrophysics Data System (ADS)
Udall, Bradley; Overpeck, Jonathan
2017-03-01
Between 2000 and 2014, annual Colorado River flows averaged 19% below the 1906-1999 average, the worst 15-year drought on record. At least one-sixth to one-half (average at one-third) of this loss is due to unprecedented temperatures (0.9°C above the 1906-1999 average), confirming model-based analysis that continued warming will likely further reduce flows. Whereas it is virtually certain that warming will continue with additional emissions of greenhouse gases to the atmosphere, there has been no observed trend toward greater precipitation in the Colorado Basin, nor are climate models in agreement that there should be a trend. Moreover, there is a significant risk of decadal and multidecadal drought in the coming century, indicating that any increase in mean precipitation will likely be offset during periods of prolonged drought. Recently published estimates of Colorado River flow sensitivity to temperature combined with a large number of recent climate model-based temperature projections indicate that continued business-as-usual warming will drive temperature-induced declines in river flow, conservatively -20% by midcentury and -35% by end-century, with support for losses exceeding -30% at midcentury and -55% at end-century. Precipitation increases may moderate these declines somewhat, but to date no such increases are evident and there is no model agreement on future precipitation changes. These results, combined with the increasing likelihood of prolonged drought in the river basin, suggest that future climate change impacts on the Colorado River flows will be much more serious than currently assumed, especially if substantial reductions in greenhouse gas emissions do not occur.
Plain Language SummaryBetween 2000 and 2014, annual Colorado River flows averaged 19% below the 1906-1999 average, the worst 15-year drought on record. Approximately one-third of the flow loss is due to high temperatures now common in the basin, a result of human caused climate change. Previous comparable droughts were caused by a lack of precipitation, not high temperatures. As temperatures increase in the 21st century due to continued human emissions of greenhouse gasses, additional temperature-induced flow losses will occur. These losses may exceed 20% at mid-century and 35% at end-century. Additional precipitation may reduce these temperature-induced losses somewhat, but to date no precipitation increases have been noted and climate models do not agree that such increases will occur. These results suggest that future climate change impacts on the Colorado River will be greater than currently assumed. Reductions in greenhouse gas emissions will lead to lower future temperatures and hence less flow loss.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28432508','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28432508"><span>Estimation of environmental flow incorporating water quality and hypothetical climate change scenarios.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Walling, Bendangtola; Chaudhary, Shushobhit; Dhanya, C T; Kumar, Arun</p> <p>2017-05-01</p> <p>Environmental flows (Eflow, hereafter) are the flows to be maintained in the river for its healthy functioning and the sustenance and protection of aquatic ecosystems. Estimation of Eflow in any river stretch demands consideration of various factors such as flow regime, ecosystem, and health of river. However, most of the Eflow estimation studies have neglected the water quality factor. This study urges the need to consider water quality criterion in the estimation of Eflow and proposes a framework for estimating Eflow incorporating water quality variations under present and hypothetical future scenarios of climate change and pollution load. The proposed framework is applied on the polluted stretch of Yamuna River passing through Delhi, India. Required Eflow at various locations along the stretch are determined by considering possible variations in future water quantity and quality. Eflow values satisfying minimum quality requirements for different river water usage classes (classes A, B, C, and D as specified by the Central Pollution Control Board, India) are found to be between 700 and 800 m 3 /s. The estimated Eflow values may aid policymakers to derive upstream storage-release policies or effluent restrictions. Generalized nature of this framework will help its implementation on any river systems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP51A2254S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP51A2254S"><span>A Riparian Approach to Dendrochronological Flow Reconstruction, Yellowstone River, Montana</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schook, D. M.; Rathburn, S. L.; Friedman, J. M.</p> <p>2015-12-01</p> <p>Tree ring-based flow reconstructions can reveal river discharge variability over durations far exceeding the gauged record, building perspective for both the measured record and future flows. We use plains cottonwood (Populus deltoides subsp. monilifera) tree rings collected from four rivers to reconstruct flow history of the Yellowstone River near its confluence with the Missouri River. Upland trees in dry regions are typically used in flow reconstruction because their annual growth is controlled by the same precipitation that drives downstream flow, but our study improves flow reconstruction by including floodplain trees that are directly affected by the river. Cores from over 1000 cottonwoods along the Yellowstone, Powder, Little Missouri, and Redwater Rivers were collected from within a 170 km radius to reconstruct flows using the Age Curve Standardization technique in a multiple regression analysis. The large sample from trees spanning many age classes allows us to use only the rings that were produced when each tree was less than 50 years old and growth was most strongly correlated to river discharge. Using trees from a range of rivers improves our ability to differentiate between growth resulting from local precipitation and river flow, and we show that cottonwood growth differs across these neighboring rivers having different watersheds. Using the program Seascorr, tree growth is found to better correlated to seasonal river discharge (R = 0.69) than to local precipitation (R = 0.45). Our flow reconstruction reveals that the most extreme multi-year or multi-decade drought periods of the last 250 years on either the Yellowstone (1817-1821) or Powder (1846-1865) Rivers are missed by the gauged discharge record. Across all sites, we document increased growth in the 20th century compared to the 19th, a finding unattainable with conventional methods but having important implications for flow management.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015HESS...19.4783M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015HESS...19.4783M"><span>South Asia river-flow projections and their implications for water resources</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mathison, C.; Wiltshire, A. J.; Falloon, P.; Challinor, A. J.</p> <p>2015-12-01</p> <p>South Asia is a region with a large and rising population, a high dependence on water intense industries, such as agriculture and a highly variable climate. In recent years, fears over the changing Asian summer monsoon (ASM) and rapidly retreating glaciers together with increasing demands for water resources have caused concern over the reliability of water resources and the potential impact on intensely irrigated crops in this region. Despite these concerns, there is a lack of climate simulations with a high enough resolution to capture the complex orography, and water resource analysis is limited by a lack of observations of the water cycle for the region. In this paper we present the first 25 km resolution regional climate projections of river flow for the South Asia region. Two global climate models (GCMs), which represent the ASM reasonably well are downscaled (1960-2100) using a regional climate model (RCM). In the absence of robust observations, ERA-Interim reanalysis is also downscaled providing a constrained estimate of the water balance for the region for comparison against the GCMs (1990-2006). The RCM river flow is routed using a river-routing model to allow analysis of present-day and future river flows through comparison with available river gauge observations. We examine how useful these simulations are for understanding potential changes in water resources for the South Asia region. In general the downscaled GCMs capture the seasonality of the river flows but overestimate the maximum river flows compared to the observations probably due to a positive rainfall bias and a lack of abstraction in the model. The simulations suggest an increasing trend in annual mean river flows for some of the river gauges in this analysis, in some cases almost doubling by the end of the century. The future maximum river-flow rates still occur during the ASM period, with a magnitude in some cases, greater than the present-day natural variability. Increases in river flow could mean additional water resources for irrigation, the largest usage of water in this region, but has implications in terms of inundation risk. These projected increases could be more than countered by changes in demand due to depleted groundwater, increases in domestic use or expansion of water intense industries. Including missing hydrological processes in the model would make these projections more robust but could also change the sign of the projections.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1984/4022/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1984/4022/report.pdf"><span>Quantity and quality of streamflow in the White River basin, Colorado and Utah</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Boyle, J.M.; Covay, K.J.; Bauer, D.P.</p> <p>1984-01-01</p> <p>The water quality and flow of existing streams in the White River basin, located in northwestern Colorado and northeastern Utah, are adequate for present uses, but future development (such as energy) may affect stream quality and quantity. Present conditions are described as a baseline to enable planners to allocate available water and to measure changes in quantity and quality of water in the future. The White River basin contains extensive energy resources consisting of oil, natural gas, coal, and oil shale. Large quantities of water will be required for energy-resource development and associated municipal and industrial uses. An average of 70% of the annual flow in the White River occurs during May, June, and July as a result of snowmelt runoff. The 7-day, 10-year low-flow discharges/sq mi and the 1-day, 25-year high-flow discharges/sq mi are larger in the eastern part of the basin than in the western part. Flow-duration curves indicate that high flows in the White River and the North and South Fork White Rivers result mainly from snowmelt runoff and that base flow is sustained throughout the year by groundwater discharge from the alluvial and bedrock aquifers. Water type varies in the basin; however, calcium and sodium are the dominantly occurring cations and sulfate and bicarbonate are the dominantly occurring anions. Computed total annual dissolved-solids loads in the White River range from 31 ,800 tons/yr in the North Fork White River to 284,000 tons/yr at the mouth. A 10% increase to a 14% decrease of the dissolved-solids load could result at the mouth of the White River near Ouray, Utah. This corresponds to a 5% increase to a 10% decrease in dissolved-solids concentration. The seasonal pattern of stream temperatures was found to fit a harmonic curve. (Lantz-PTT)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5066962','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5066962"><span>Projected Impact of Climate Change on Hydrological Regimes in the Philippines</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kanamaru, Hideki; Keesstra, Saskia; Maroulis, Jerry; David, Carlos Primo C.; Ritsema, Coen J.</p> <p>2016-01-01</p> <p>The Philippines is one of the most vulnerable countries in the world to the potential impacts of climate change. To fully understand these potential impacts, especially on future hydrological regimes and water resources (2010-2050), 24 river basins located in the major agricultural provinces throughout the Philippines were assessed. Calibrated using existing historical interpolated climate data, the STREAM model was used to assess future river flows derived from three global climate models (BCM2, CNCM3 and MPEH5) under two plausible scenarios (A1B and A2) and then compared with baseline scenarios (20th century). Results predict a general increase in water availability for most parts of the country. For the A1B scenario, CNCM3 and MPEH5 models predict an overall increase in river flows and river flow variability for most basins, with higher flow magnitudes and flow variability, while an increase in peak flow return periods is predicted for the middle and southern parts of the country during the wet season. However, in the north, the prognosis is for an increase in peak flow return periods for both wet and dry seasons. These findings suggest a general increase in water availability for agriculture, however, there is also the increased threat of flooding and enhanced soil erosion throughout the country. PMID:27749908</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H43A1610M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H43A1610M"><span>Quantifying Changes in Los Angeles River Breakout Triggered by Sea Level Rise Using a Hydrodynamic Model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mallakpour, I.; Shakeri Majd, M.; AghaKouchak, A.; Moftakhari, H.; Sadegh, M.; Vahedifard, F.</p> <p>2017-12-01</p> <p>Sea Level Rise (SLR) has been identified as a global phenomenon that will challenge coastal communities and infrastructures through escalating risk of erosion and subsidence, as well as elevating storm surge heights. Overall, SLR not only increases frequency of future coastal flooding in low-land coastal areas, but also changes flow dynamics in rivers connected to oceans. Changes in flow dynamics (e.g., peaks, flow intensities) can elevate water surface profile locally, leading to river breakout and flooding. Quantifying river breakout provides invaluable information to local authorities when it comes to SLR mitigation and adaptation efforts. Los Angeles River (LAR) which is located in southern part of California is protected with levee systems. The focus of this study is about 18 miles of the river, starting from Pacific Ocean to Downtown Los Angeles, which protects residence and major infrastructures. We use the Hydrologic Engineering Center's River Analysis System (HEC-RAS) to simulate flow and its interactions with coastal water levels. HEC-RAS is capable of simulating flow in one- and two-dimensional systems, resolving Diffusive Wave Equation and Shallow Water Equation, respectively. In this study, the hydraulic model consists of one- and two-dimensional models connected through the LAR's levee system. This approach enables us to identify the onset of river breakout location alongside the LAR. The inflow data incorporated into the model obtained from a gage records and represents a significant event occurred in February 2005. This model utilizes a detail terrain model with 0.3 m LiDAR data. In order to explore effects of SLR associated with future climate changes on LAR and its levee system, two Representative Concentration Pathways (RCP of 4.5 and 8.5) are considered. Based on our RCPs, 24 projected SLRs are computed for future years (2030, 2050, and 2100) for three different quantiles. Our simulation results show SLR, which varies from 0.05 to 2.8 m, causes backwater at the mouth of the river, at Pacific Ocean. Consequently, flow velocities and depth changes in channel, which results in changes in onset and location of the river breakout. Our findings emphasize needs for incorporating effects of SLR in hydraulic models in order to support mitigation and adaption efforts.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H43I1350S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H43I1350S"><span>Space-Time Variability in River Flow Regimes of Northeast Turkey</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saris, F.; Hannah, D. M.; Eastwood, W. J.</p> <p>2011-12-01</p> <p>The northeast region of Turkey is characterised by relatively high annual precipitation totals and river flow. It is a mountainous region with high ecological status and also it is of prime interest to the energy sector. These characteristics make this region an important area for a hydroclimatology research in terms of future availability and management of water resources. However, there is not any previous research identifying hydroclimatological variability across the region. This study provides first comprehensive and detailed information on river flow regimes of northeast Turkey which is delimited by two major river basins namely East Black Sea (EBS) and Çoruh River (ÇRB) basins. A novel river flow classification is used that yields a large-scale perspective on hydroclimatology patterns of the region and allows interpretations regarding the controlling factors on river flow variability. River flow regimes are classified (with respect to timing and magnitude of flow) to examine spatial variability based on long-term average regimes, and also by grouping annual regimes for each station-year to identify temporal (between-year) variability. Results indicate that rivers in northeast Turkey are characterised by marked seasonal flow variation with an April-May-June maximum flow period. Spatial variability in flow regime seasonality is dependent largely on the topography of the study area. The EBS Basin, for which the North Anatolian Mountains cover the eastern part, is characterised by a May-June peak; whereas the ÇRB is defined by an April-May flow peak. The timing of river flows indicates that snowmelt is an important process and contributor of river flow maxima for both basins. The low flow season is January and February. Intermediate and low regime magnitude classes dominate in ÇRB and EBS basins, respectively, while high flow magnitude class is observed for one station only across the region. Result of regime stability analysis (year-to-year variation) shows that April-May and May-June peak shape classes together with low and intermediate magnitude classes are the most frequent and persistent flow regimes. This research has advanced understanding of hydroclimatological processes in northeast Turkey by identifying river flow regimes and together with explanations regarding the controlling factors on river flow variability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2010/5142/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2010/5142/"><span>Hydrogeology and numerical simulation of the unconsolidated glacial aquifer in the Pootatuck River Basin, Newtown, Connecticut</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Carlson, Carl S.; Mondazzi, Remo A.; Bjerklie, David M.; Brown, Craig J.</p> <p>2010-01-01</p> <p>A study of the groundwater and stream-aquifer interaction in the Pootatuck River Basin, Newtown, Connecticut, was conducted to analyze the effect of production wells on the groundwater levels and streamflow in the Pootatuck River as part of a cooperative program between the U.S. Geological Survey and Newtown, Connecticut. This study will help address concerns about the increasing competition for water for human uses and protection of aquatic habitat. The groundwater-flow model developed in the study was designed for use as a tool to assist planners in assessing the effects of potential future development, which will change the amount and distribution of recharge available to the groundwater system. Several different techniques were used to investigate the interconnection between the stream and the aquifer. Temperature, groundwater levels, stream stage, and stable-isotope data collected during aquifer tests at the principal production wells in the Pootatuck River Basin, as well as groundwater-flow simulations of the system, indicate that more than half of the water pumped from the wells comes from the Pootatuck River. This finding potentially has a large effect on approaches for protecting the water quality of the pumped water. Increases in the amount of impervious surface from future development will reduce and redistribute recharge to the groundwater system. The simulation of future development scenarios showed a decrease in the simulated base flow in the main stem of the Pootatuck River and in all of the 26 simulated subbasins, with some of the subbasins showing a decrease of more than 20 percent when new development had 85 percent impervious area. The groundwater-flow model and particle tracking were used to determine areas that contribute recharge to the five production wells available for use in the Pootatuck River Basin. These areas included narrow portions of the aquifer that extended beyond the immediate upgradient areas, probably because of deeper groundwater-flow paths.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70174942','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70174942"><span>A water balance model to estimate flow through the Old and Middle River corridor</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Andrews, Stephen W.; Gross, Edward S.; Hutton, Paul H.</p> <p>2016-01-01</p> <p>We applied a water balance model to predict tidally averaged (subtidal) flows through the Old River and Middle River corridor in the Sacramento–San Joaquin Delta. We reviewed the dynamics that govern subtidal flows and water levels and adopted a simplified representation. In this water balance approach, we estimated ungaged flows as linear functions of known (or specified) flows. We assumed that subtidal storage within the control volume varies because of fortnightly variation in subtidal water level, Delta inflow, and barometric pressure. The water balance model effectively predicts subtidal flows and approaches the accuracy of a 1–D Delta hydrodynamic model. We explore the potential to improve the approach by representing more complex dynamics and identify possible future improvements.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/ds/0974/ds974.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/ds/0974/ds974.pdf"><span>Modeled streamflow metrics on small, ungaged stream reaches in the Upper Colorado River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Reynolds, Lindsay V.; Shafroth, Patrick B.</p> <p>2016-01-20</p> <p>Modeling streamflow is an important approach for understanding landscape-scale drivers of flow and estimating flows where there are no streamgage records. In this study conducted by the U.S. Geological Survey in cooperation with Colorado State University, the objectives were to model streamflow metrics on small, ungaged streams in the Upper Colorado River Basin and identify streams that are potentially threatened with becoming intermittent under drier climate conditions. The Upper Colorado River Basin is a region that is critical for water resources and also projected to experience large future climate shifts toward a drying climate. A random forest modeling approach was used to model the relationship between streamflow metrics and environmental variables. Flow metrics were then projected to ungaged reaches in the Upper Colorado River Basin using environmental variables for each stream, represented as raster cells, in the basin. Last, the projected random forest models of minimum flow coefficient of variation and specific mean daily flow were used to highlight streams that had greater than 61.84 percent minimum flow coefficient of variation and less than 0.096 specific mean daily flow and suggested that these streams will be most threatened to shift to intermittent flow regimes under drier climate conditions. Map projection products can help scientists, land managers, and policymakers understand current hydrology in the Upper Colorado River Basin and make informed decisions regarding water resources. With knowledge of which streams are likely to undergo significant drying in the future, managers and scientists can plan for stream-dependent ecosystems and human water users.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JHyd..544..438H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JHyd..544..438H"><span>Suwannee River flow variability 1550-2005 CE reconstructed from a multispecies tree-ring network</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harley, Grant L.; Maxwell, Justin T.; Larson, Evan; Grissino-Mayer, Henri D.; Henderson, Joseph; Huffman, Jean</p> <p>2017-01-01</p> <p>Understanding the long-term natural flow regime of rivers enables resource managers to more accurately model water level variability. Models for managing water resources are important in Florida where population increase is escalating demand on water resources and infrastructure. The Suwannee River is the second largest river system in Florida and the least impacted by anthropogenic disturbance. We used new and existing tree-ring chronologies from multiple species to reconstruct mean March-October discharge for the Suwannee River during the period 1550-2005 CE and place the short period of instrumental flows (since 1927 CE) into historical context. We used a nested principal components regression method to maximize the use of chronologies with varying time coverage in the network. Modeled streamflow estimates indicated that instrumental period flow conditions do not adequately capture the full range of Suwannee River flow variability beyond the observational period. Although extreme dry and wet events occurred in the gage record, pluvials and droughts that eclipse the intensity and duration of instrumental events occurred during the 16-19th centuries. The most prolonged and severe dry conditions during the past 450 years occurred during the 1560s CE. In this prolonged drought period mean flow was estimated at 17% of the mean instrumental period flow. Significant peaks in spectral density at 2-7, 10, 45, and 85-year periodicities indicated the important influence of coupled oceanic-atmospheric processes on Suwannee River streamflow over the past four centuries, though the strength of these periodicities varied over time. Future water planning based on current flow expectations could prove devastating to natural and human systems if a prolonged and severe drought mirroring the 16th and 18th century events occurred. Future work in the region will focus on updating existing tree-ring chronologies and developing new collections from moisture-sensitive sites to improve understandings of past hydroclimate in the region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.B31H0573N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.B31H0573N"><span>Hydrological and Climate Controls on Hyporheic Contributions to River Net Ecosystem Productivity</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newcomer, M. E.; Hubbard, S. S.; Fleckenstein, J. H.; Maier, U.; Schmidt, C.; Laube, G.; Chen, N.; Ulrich, C.; Dwivedi, D.; Steefel, C. I.; Rubin, Y.</p> <p>2016-12-01</p> <p>Hyporheic zone contributions to river net ecosystem productivity (NEP) can represent a substantial source or sink for organic and inorganic carbon (C). Hyporheic zone processes are estimated to vary with network location as a function of river-aquifer interactions as well as with climatic factors supporting riverbed gross primary productivity (GPP) and ecosystem respiration. Even though hyporheic zone NEP is hypothesized to be a significant budgetary component to river-aquifer biogeochemical cycling, models of river NEP often parameterize hyporheic zone contributions as a space-time constant input of CO2 to rivers, leading to overestimation of hyporheic zone NEP and underestimation of C storage. This assumption is problematic during the summer growing season, when GPP is largest and C is stored in surface and subsurface biomass. We investigated the dynamic role of hyporheic zone NEP using the MIN3P flow and reactive transport model with surface water GPP and ecosystem respiration simulated as a function of light, depth, temperature, pH, and atmospheric CO2. We simulated hyporheic zone NEP for low-order and high-order streams, which collectively represent a range of characteristic flow paths and subsurface residence times. Downscaled climate predictions of temperature and atmospheric CO2 representing carbon emission futures were used to force the models and to compare future and current hyporheic zone NEP. Our results show that river-aquifer flow conditions determine the relative role of the river as either a store or sink of C through direct contributions of O2 and dissolved organic content from river GPP. Modeled results show that high discharge, high order rivers are net stores of CO2 from the atmosphere; however this is dependent on perturbation events that allow stored C from summer GPP to be released (i.e. rising water tables during winter storms). Lacking a perturbation event, C remains in pore-water storage as dissolved CO2 and biomass. Conversely, low-discharge mountainous streams with continuous hyporheic zone flow represent a net source of CO2, with future temperature rises stimulating additional heterotrophic activity. Our work contributes to a better understanding of how river and hyporheic zone processes significantly influence biogeochemical cycling under changing climate conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990080919&hterms=sea+world&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsea%2Bworld','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990080919&hterms=sea+world&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsea%2Bworld"><span>Modeling the Effect of Wetlands, Flooding, and Irrigation on River Flow: Application to the Aral Sea</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ferrari, Michael R.; Miller, James R.; Russell, Gary L.</p> <p>1999-01-01</p> <p>As the world's population continues to increase, additional stress is placed on water resources. This stress, coupled with future uncertainties regarding climate change, makes arid and semi-arid regions particularly vulnerable. One example is the Aral Sea where the freshwater inflow, which is dominated by snowmelt runoff, has decreased significantly since the expansion of intensive irrigation in the 1960s. The purpose of this paper is to use a river routing scheme from a global climate model to examine the flow of the Amu Dar'ya River into the Aral Sea. The river routing scheme is modified to include groundwater flow, flooding, and evaporative losses in the river's wetlands and floodplain, and anthropogenic withdrawals for irrigation. A set of scenarios is designed to test the sensitivity of river flow to the inclusion of these modifications into the river routing scheme. When riverine wetlands and floodplains are present, the river flow is reduced significantly and is similar to the observed flow. In addition the model results show that it is essential to incorporate human diversions to accurately represent the inflow to the Aral Sea, and they also indicate potential management strategies that might be appropriate to maintain a balance between inflow to the Sea and upstream diversions for irrigation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999WRR....35.1869F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999WRR....35.1869F"><span>Modeling the effect of wetlands, flooding, and irrigation on river flow: Application to the Aral Sea</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ferrari, Michael R.; Miller, James R.; Russell, Gary L.</p> <p>1999-06-01</p> <p>As the world's population continues to increase, additional stress is placed on water resources. This stress, coupled with future uncertainties regarding climate change, makes arid and semiarid regions particularly vulnerable. One example is the Aral Sea where the freshwater inflow, which is dominated by snowmelt runoff, has decreased significantly since the expansion of intensive irrigation in the 1960s. The purpose of this paper is to use a river routing scheme from a global climate model to examine the flow of the Amu Dar'ya River into the Aral Sea. The river routing scheme is modified to include groundwater flow, flooding, and evaporative losses in the river's wetlands and floodplain and anthropogenic withdrawals for irrigation. A set of scenarios is designed to test the sensitivity of river flow to the inclusion of these modifications into the river routing scheme. When riverine wetlands and floodplains are present, the river flow is reduced significantly and is similar to the observed flow. In addition, the model results show that it is essential to incorporate human diversions to represent accurately the inflow to the Aral Sea, and they also indicate potential management strategies that might be appropriate to maintain a balance between inflow to the sea and upstream diversions for irrigation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPA42A..02G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPA42A..02G"><span>Why understanding the impacts of the changing environment on river basin hydrology matters in Texas?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, H.; Zhao, G.; Lee, K.; Zhang, S.; Shen, X.; Shao, M.; Nickelson, C.</p> <p>2017-12-01</p> <p>The State of Texas is prone to floods and droughts—both of which are expected to become more frequent, and more intensified, under a changing climate. This has a direct negative effect on agricultural productivity, which is a major revenue source for the state. Meanwhile, with the rapid population growth and economic development, the burden to Texas water resources is exacerbated by the ever increasing demands from users. From a hydrological processes perspective, the direct consequence of the increased impervious area due to urbanization is greater surface runoff and higher flood peaks. Although many reservoirs have been built during the past several decades to regulate river flows and increase water supply, the role of these reservoirs in the context of different future climate change and urbanization scenarios needs to be explored. Furthermore, phytoplankton productivity—an important indicator of coastal ecosystem health— is significantly affected by river discharge. The objective of this presentation is to reveal the importance of understanding the impacts of climate change, urbanization, and flow regulation on Texas river flows, water resources, and coastal water quality. Using state-of-the-art modeling and remote sensing techniques, we will showcase our results over representative Texas river basins and bay areas. A few examples include modeling peak flows in the San Antonio River Basin, evaluating water supply resilience under future drought and urbanization over the Dallas metropolitan area, projecting future crop yields from Texas agricultural lands, and monitoring and forecasting Chlorophyll-a concentrations over Galveston Bay. Results from these studies are expected to provide information relevant to decision making, both with regard to water resources management and to ecosystem protection.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPA11C..06U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPA11C..06U"><span>Global Change Drought in the Southwest: New Management Options</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Udall, B. H.; Overpeck, J. T.</p> <p>2015-12-01</p> <p>Long held worries about future runoff declines in the Colorado River under climate change are proving to be more than just theory. Fifteen years into this century flows of the Colorado are already declining due mostly to unprecedented temperatures, and as warming proceeds, declines in river flow will grow larger. Temperature-driven droughts, some lasting decades and much more severe than the current 15-year drought, will also become more commonplace if climate change continues unabated. Current projections of future water availability almost universally understate the risk of large Colorado flow reductions under business-as-usual warming. Betting on highly uncertain projections of increased precipitation to overcome even part of the flow reductions due to virtually certain warming is a poor risk management strategy. Many of the existing water policy arrangements in the Colorado River Basin will fail in the 21st century unless innovative new solutions are developed under leadership from the federal government and its basin state partners.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29801202','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29801202"><span>Modeling future flows of the Volta River system: Impacts of climate change and socio-economic changes.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jin, Li; Whitehead, Paul G; Appeaning Addo, Kwasi; Amisigo, Barnabas; Macadam, Ian; Janes, Tamara; Crossman, Jill; Nicholls, Robert J; McCartney, Matthew; Rodda, Harvey J E</p> <p>2018-10-01</p> <p>As the scientific consensus concerning global climate change has increased in recent decades, research on potential impacts of climate change on water resources has been given high importance. However in Sub-Saharan Africa, few studies have fully evaluated the potential implications of climate change to their water resource systems. The Volta River is one of the major rivers in Africa covering six riparian countries (mainly Ghana and Burkina Faso). It is a principal water source for approximately 24 million people in the region. The catchment is primarily agricultural providing food supplies to rural areas, demonstrating the classic water, food, energy nexus. In this study an Integrated Catchment Model (INCA) was applied to the whole Volta River system to simulate flow in the rivers and at the outlet of the artificial Lake Volta. High-resolution climate scenarios downscaled from three different Global Climate Models (CNRM-CM5, HadGEM2-ES and CanESM2), have been used to drive the INCA model and to assess changes in flow by 2050s and 2090s under the high climate forcing scenario RCP8.5. Results show that peak flows during the monsoon months could increase into the future. The duration of high flow could become longer compared to the recent condition. In addition, we considered three different socio-economic scenarios. As an example, under the combined impact from climate change from downscaling CNRM-CM5 and medium+ (high economic growth) socio-economic changes, the extreme high flows (Q5) of the Black Volta River are projected to increase 11% and 36% at 2050s and 2090s, respectively. Lake Volta outflow would increase +1% and +5% at 2050s and 2090s, respectively, under the same scenario. The effects of changing socio-economic conditions on flow are minor compared to the climate change impact. These results will provide valuable information assisting future water resource development and adaptive strategies in the Volta Basin. Copyright © 2018 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.H23L..07W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.H23L..07W"><span>Can the Gila River reduce risk in the Colorado River Basin?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wade, L. C.; Rajagopalan, B.; Lukas, J.; Kanzer, D.</p> <p>2012-12-01</p> <p>The Colorado River is the most important source of water in the southwest United States and Northern Mexico, providing water to approximately 35 million people and 4-5 million acres of irrigated lands. To manage the water resources of the basin, estimated to be about 17 million acre-feet (MAF) of undepleted supplies per year, managers use reservoir facilities that can store more than 60 MAF. As the demands on the water resources of the basin approach or exceed the average annual supply, and with average flow projected to decrease due to climate change, smart water management is vital for its sustainability. To quantify the future risk of depleting reservoir storage, Rajagopalan et al. (2009) developed a water-balance model and ran it under scenarios based on historical, paleo-reconstructed and future projections of flows, and different management alternatives. That study did not consider the impact of the Gila River, which enters the Colorado River below all major reservoirs and U.S. diversions. Due to intensive use in Central Arizona, the Gila only has significant inflows to the Colorado in wet years. However, these irregular inflows could beneficially influence system reliability in the US by helping to meet a portion of the 1.5 MAF delivery obligations to Mexico. To help quantify the potential system reliability benefit of the Gila River, we modify the Rajagopalan et al (2009) model to incorporate simulated Gila River inflows. These new data inputs to the water balance model are based on historical flows and tree-ring reconstructions of flow in the Upper Colorado River Basin (at Lee's Ferry), the Lower Colorado River Basin (tributary inflows), and the intermittent flows from the Gila River which are generated using extreme value analysis methods. Incorporating Gila River inflows, although they are highly variable and intermittent, reduces the modeled cumulative risk of reservoir depletion by 4 to 11% by 2057, depending on the demand schedule, reservoir operation guidelines, and climate change scenario assumptions. This potential risk mitigation could be at least partly realized through enhancements to current management practices, possibly in the Gila River, that could improve the water supply reliability for all stakeholders in the Colorado River Basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H43B1194G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H43B1194G"><span>Assesment of future river habitat suitability under climate change scenarios in a mesoscale Alpine watershed of Italy (Serio River, Italian Alps)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Groppelli, B.; Confortola, G.; Soncini, A.; Bocchiola, D.; Rosso, R.</p> <p>2011-12-01</p> <p>We merge hydraulic river modelling, use of suitability functions for fish guild colonization and hydrological modelling of catchment response to investigate future (until 2100) hydrological cycle and fish habitat suitability for an Alpine catchment in Italy, Serio river (drainage area 450 Km2, average altitude 1300 m a.s.l., main channel length ca. 36 km). Based upon detailed river channel morphology data for 73 river sections and direct local investigation we then set up and tune a quasi 2-D (i.e. with floodplains) hydraulic model for in channel flows hydraulics, depending upon daily in stream discharge. We then evaluate distributed values of hydraulic variables and therein composite habitat suitability indexes CS for a representative target species (brown trout, Salmo Trutta Fario L.), resulting into usable wetted area WUA for fish colonization. We consider both juvenile JUV and adults AD, and we evaluate the frequency (days in a year/season) of yearly/seasonal, spatially distributed and bulk (whole stream) habitat quality. We then provide synthetic indicators of (yearly/seasonal) suitability level and duration within the river. We then set up a minimal (T, P), properly tuned hydrological model able to mimick Serio river's hydrological cycle. We then use downscaled future precipitation and temperature from three general circulation models, GCMs (PCM, CCSM3, and HadCM3) available within the IPCC's data base chosen for the purpose based upon previous studies, to feed our hydrological model and provide projected hydrological regime of the catchment, together with modified habitat suitability. We then comment upon modified flow regime, habitat suitability as obtained and related uncertainty. The proposed results may be of use for river managers and may provide a template for investigation about future river habitat quality pending climate change.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_2 --> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H41I..01H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H41I..01H"><span>Unravelling connections between river flow and large-scale climate: experiences from Europe</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hannah, D. M.; Kingston, D. G.; Lavers, D.; Stagge, J. H.; Tallaksen, L. M.</p> <p>2016-12-01</p> <p>The United Nations has identified better knowledge of large-scale water cycle processes as essential for socio-economic development and global water-food-energy security. In this context, and given the ever-growing concerns about climate change/ variability and human impacts on hydrology, there is an urgent research need: (a) to quantify space-time variability in regional river flow, and (b) to improve hydroclimatological understanding of climate-flow connections as a basis for identifying current and future water-related issues. In this paper, we draw together studies undertaken at the pan-European scale: (1) to evaluate current methods for assessing space-time dynamics for different streamflow metrics (annual regimes, low flows and high flows) and for linking flow variability to atmospheric drivers (circulation indices, air-masses, gridded climate fields and vapour flux); and (2) to propose a plan for future research connecting streamflow and the atmospheric conditions in Europe and elsewhere. We believe this research makes a useful, unique contribution to the literature through a systematic inter-comparison of different streamflow metrics and atmospheric descriptors. In our findings, we highlight the need to consider appropriate atmospheric descriptors (dependent on the target flow metric and region of interest) and to develop analytical techniques that best characterise connections in the ocean-atmosphere-land surface process chain. We call for the need to consider not only atmospheric interactions, but also the role of the river basin-scale terrestrial hydrological processes in modifying the climate signal response of river flows.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=321494&Lab=NERL&keyword=Descriptive+AND+research&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=321494&Lab=NERL&keyword=Descriptive+AND+research&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Ecological research and management of intermittent rivers: an historical review and future directions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Rivers and streams that do not flow permanently (herein intermittent rivers; IRs) make up a large proportion of the world's inland waters and are gaining widespread attention. We review the research on IRs from its early focus on natural history through to current application in ...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2013/5173/pdf/sir2013-5173.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2013/5173/pdf/sir2013-5173.pdf"><span>Streamflow statistics for unregulated and regulated conditions for selected locations on the Yellowstone, Tongue, and Powder Rivers, Montana, 1928-2002</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chase, Katherine J.</p> <p>2013-01-01</p> <p>Major floods in 1996 and 1997 on the Yellowstone River in Montana intensified public debate over the effects of human activities on the Yellowstone River. In 1999, the Yellowstone River Conservation District Council was formed to address conservation issues on the river. The Yellowstone River Conservation District Council partnered with the U.S. Army Corps of Engineers to conduct a cumulative-effects study on the main stem of the Yellowstone River. The cumulative-effects study is intended to provide a basis for future management decisions in the watershed. Streamflow statistics, such as flow-frequency and flow-duration data calculated for unregulated and regulated streamflow conditions, are a necessary component of the cumulative effects study. The U.S. Geological Survey, in cooperation with the Yellowstone River Conservation District Council and the U.S. Army Corps of Engineers, calculated streamflow statistics for unregulated and regulated conditions for the Yellowstone, Tongue, and Powder Rivers for the 1928–2002 study period. Unregulated streamflow represents flow conditions that might have occurred during the 1928–2002 study period if there had been no water-resources development in the Yellowstone River Basin. Regulated streamflow represents estimates of flow conditions during the 1928–2002 study period if the level of water-resources development existing in 2002 was in place during the entire study period. Peak-flow frequency estimates for regulated and unregulated streamflow were developed using methods described in Bulletin 17B. High-flow frequency and low-flow frequency data were developed for regulated and unregulated streamflows from the annual series of highest and lowest (respectively) mean flows for specified n-day consecutive periods within the calendar year. Flow-duration data, and monthly and annual streamflow characteristics, also were calculated for the unregulated and regulated streamflows.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2007/5107/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2007/5107/"><span>Two-Dimensional Flood-Inundation Model of the Flint River at Albany, Georgia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Musser, Jonathan W.; Dyar, Thomas R.</p> <p>2007-01-01</p> <p>Potential flow characteristics of future flooding along a 4.8-mile reach of the Flint River in Albany, Georgia, were simulated using recent digital-elevation-model data and the U.S. Geological Survey finite-element surface-water modeling system for two-dimensional flow in the horizontal plane (FESWMS-2DH). Simulated inundated areas, in 1-foot (ft) increments, were created for water-surface altitudes at the Flint River at Albany streamgage (02352500) from 192.5-ft altitude with a flow of 123,000 cubic feet per second (ft3/s) to 179.5-ft altitude with a flow of 52,500 ft3/s. The model was calibrated to match actual floods during July 1994 and March 2005 and Federal Emergency Management Administration floodplain maps. Continuity checks of selected stream profiles indicate the area near the Oakridge Drive bridge had lower velocities than other areas of the Flint River, which contributed to a rise in the flood-surface profile. The modeled inundated areas were mapped onto monochrome orthophoto imagery for use in planning for future floods. As part of a cooperative effort, the U.S. Geological Survey, the City of Albany, and Dougherty County, Georgia, conducted this study.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C41F..02Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C41F..02Q"><span>Predicting the Future Contribution of Himalayan Debris-covered Glaciers to River Discharge: Advances and Challenges</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quincey, D. J.; Hubbard, B. P.; Klaar, M. J.; Miles, E.; Miles, K.; Rowan, A. V.; King, O.; Watson, C. S.</p> <p>2017-12-01</p> <p>The glaciers and snowfields of the Himalaya are the ultimate source for the many rivers that flow across the Asian subcontinent, but they are diminishing rapidly in the face of sustained climatic change. Predictions of how future river discharge may vary through space and time are hampered by two major knowledge gaps. First, simulations of glacier mass loss in high Asia are severely limited by data availability and assumptions made in the parameterisation of glacier models. Consequently, projections of glacier change vary widely; in Nepal for example, recent estimates of volumetric ice loss by AD2100 have ranged between 8% and 99%. A second major gap in knowledge lies in the coupling between glaciers and downstream areas, and specifically in quantifying the relative contributions of different sources to river flow. Although it is clear that ice and snow melt dominates flow for considerable distances downstream, how this contribution interacts with groundwater supplies with increasing distance from its source remains poorly understood. This presentation will review recent work that closes some of the knowledge gaps in understanding debris-covered glacier behaviour including new results from drilling work on the Khumbu Glacier in Nepal. Additionally, it will report on the outputs from an interdisciplinary study in the Annapurna region of Nepal, which is focussing specifically on disaggregating the relative contributions to flow using isotope-based hydrograph separations. It will finish by exploring the most likely drivers of future changes to water supply, including an evaluation of the impact of glacial lake development, and by identifying the main challenges for future related research.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70150351','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70150351"><span>Mount Baker lahars and debris flows, ancient, modern, and future</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Tucker, David S; Scott, Kevin M.; Grossman, Eric E.; Linneman, Scott</p> <p>2014-01-01</p> <p>Holocene lahars and large debris flows (>106 m3) have left recognizable deposits in the Middle Fork Nooksack valley. A debris flow in 2013 resulting from a landslide in a Little Ice Age moraine had an estimated volume of 100,000 m3, yet affected turbidity for the entire length of the river, and produced a slug of sediment that is currently being reworked and remobilized in the river system. Deposits of smaller-volume debris flows, deposited as terraces in the upper valley, may be entirely eroded within a few years. Consequently, the geologic record of small debris flows such as those that occurred in 2013 is probably very fragmentary. Small debris flows may still have significant impacts on hydrology, biology, and human uses of rivers downstream. Impacts include the addition of waves of fine sediment to stream loads, scouring or burying salmon-spawning gravels, forcing unplanned and sudden closure of municipal water intakes, damaging or destroying trail crossings, extending river deltas into estuaries, and adding to silting of harbors near river mouths.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21442295','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21442295"><span>Hydrological classification of natural flow regimes to support environmental flow assessments in intensively regulated Mediterranean rivers, Segura River Basin (Spain).</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Belmar, Oscar; Velasco, Josefa; Martinez-Capel, Francisco</p> <p>2011-05-01</p> <p>Hydrological classification constitutes the first step of a new holistic framework for developing regional environmental flow criteria: the "Ecological Limits of Hydrologic Alteration (ELOHA)". The aim of this study was to develop a classification for 390 stream sections of the Segura River Basin based on 73 hydrological indices that characterize their natural flow regimes. The hydrological indices were calculated with 25 years of natural monthly flows (1980/81-2005/06) derived from a rainfall-runoff model developed by the Spanish Ministry of Environment and Public Works. These indices included, at a monthly or annual basis, measures of duration of droughts and central tendency and dispersion of flow magnitude (average, low and high flow conditions). Principal Component Analysis (PCA) indicated high redundancy among most hydrological indices, as well as two gradients: flow magnitude for mainstream rivers and temporal variability for tributary streams. A classification with eight flow-regime classes was chosen as the most easily interpretable in the Segura River Basin, which was supported by ANOSIM analyses. These classes can be simplified in 4 broader groups, with different seasonal discharge pattern: large rivers, perennial stable streams, perennial seasonal streams and intermittent and ephemeral streams. They showed a high degree of spatial cohesion, following a gradient associated with climatic aridity from NW to SE, and were well defined in terms of the fundamental variables in Mediterranean streams: magnitude and temporal variability of flows. Therefore, this classification is a fundamental tool to support water management and planning in the Segura River Basin. Future research will allow us to study the flow alteration-ecological response relationship for each river type, and set the basis to design scientifically credible environmental flows following the ELOHA framework.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28886914','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28886914"><span>Mapping eutrophication risk from climate change: Future phosphorus concentrations in English rivers.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Charlton, Matthew B; Bowes, Michael J; Hutchins, Michael G; Orr, Harriet G; Soley, Rob; Davison, Paul</p> <p>2018-02-01</p> <p>Climate change is expected to increase eutrophication risk in rivers yet few studies identify the timescale or spatial extent of such impacts. Phosphorus concentration, considered the primary driver of eutrophication risk in English rivers, may increase through reduced dilution particularly if river flows are lower in summer. Detailed models can indicate change in catchment phosphorus concentrations but targeted support for mitigation measures requires a national scale evaluation of risk. In this study, a load apportionment model is used to describe the current relationship between flow and total reactive phosphorus (TRP) at 115 river sites across England. These relationships are used to estimate TRP concentrations for the 2050s under 11 climate change driven scenarios of future river flows and under scenarios of both current and higher levels of sewage treatment. National maps of change indicate a small but inconsistent increase in annual average TRP concentrations with a greater change in summer. Reducing the TRP concentration of final sewage effluent to 0.5mg/L P for all upstream sewage treatment works was inadequate to meet existing P standards required through the EU Water Framework Directive, indicating that more needs to be done, including efforts to reduce diffuse pollution. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1972/0157/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1972/0157/report.pdf"><span>Hydrologic analysis of Mojave River Basin, California, using electric analog model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hardt, W.F.</p> <p>1971-01-01</p> <p>The water needs of the Mojave River basin will increase because of population and industrial growth. The Mojave Water Agency is responsible for providing sufficient water of good quality for the full economic development of the area. The U.S. Geological Survey suggested an electric analog model of the basin as a predictive tool to aid management. About 1,375 square miles of the alluvial basin was simulated by a passive resistor-capacitor network. The Mojave River, the main source of recharge, was simulated by subdividing the river into 13 reaches, depending on intermittent or perennial flow and on phreatophytes. The water loss to the aquifer was based on records at five gaging stations. The aquifer system depends on river recharge to maintain the water table as most of the ground-water pumping and development is adjacent to the river. The accuracy and reliability of the model was assessed by comparing the water-level changes computed by the model for the period 1930-63 with the changes determined from field data for the same period. The model was used to predict the effects on the physical system by determining basin-wide water-level changes from 1930-2000 under different pumping rates and extremes in flow of the Mojave River. Future pumping was based on the 1960-63 rate, on an increase of 20 percent from this rate, and on population projections to 2000 in the Barstow area. For future predictions, the Mojave River was modeled as average flow based on 1931-65 records and also as high flow, 1937-46, and low flow, 1947-65. Other model runs included water-level change 1930-63 assuming aquifer depletion only and no recharge, effects of a well field pumping 10,000 acre-feet in 4 months north of Victorville and southeast of Yermo, and effects of importing 10,000, 35,000, and 50,800 acre-feet of water per year from the California Water Project into the Mojave River for conveyance downstream.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC13E1243M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC13E1243M"><span>Ensembles of 21st Century Colorado River Flow Projections Exhibit Substantial Diversity in Response to Seasonal Hydroclimatic Scenarios</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McAfee, S. A.; Woodhouse, C. A.; McCabe, G. J., Jr.; Pederson, G. T.</p> <p>2016-12-01</p> <p>Approximately 40 million people depend on the Colorado River, and that number is likely to grow in the future, making the River's response to projected increases in temperature and possible changes in precipitation a critical societal issue. By far the most common way of approaching the problem is synthesize results obtained by forcing a hydrological model with a set of downscaled future climate scenarios. One weakness with this type of analysis is that full hydrologic model simulations can be computationally demanding, and so the number of potential climate futures is generally somewhat limited. Here we sidestep that issue by using a very large set of synthetic climate futures to drive a simple statistical model of water year flow at Lees Ferry. 62,500 climate series, comprising 500 iterations of 125 unique combinations of summer temperature changes ranging from 0 to +4°C and summer and winter precipitation changes ranging from -20 to +20% were input into the flow model. Without substantial temperature increases, significant increases in the occurrence of very low flows (<75%) were unlikely, even with sharp decreases in temperature. Conversely, increases in precipitation, could buffer the effect of summer temperature increases up to about 3°C on mean water year flows. While very simple models like this one are inappropriate for some questions, they do provide an effective way of prioritizing and framing more complex investigations, and facilitate conversations with stakeholders about research directions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.H23C0967W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.H23C0967W"><span>Future Management and Control of the Lower Mississippi River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Willson, C. S.; Karadogan, E.</p> <p>2009-12-01</p> <p>In many ways the Mississippi River, which drains an area of over 1,245,000 square miles (covering 31 states and two Canadian provinces), is a highly engineered system due to the presence of control structures and levees. These features provide the necessary controls for flood protection and for sustaining navigation routes to a number of economically important ports. The lower portion of the River is subject to temporally dynamic forcings due to the high variability in annual flow rates (up to 700,000 cfs) and Gulf of Mexico conditions, both of which are expected to change over the coming decades as a result of climate change. Another phenomena that is having a major impact on the lower River delta is subsidence---some parts of coastal Louisiana are experiencing subsidence rates of up to 1 cm/year. As a result, the relative sea level rise rates in coastal Louisiana will be higher than many other delta systems throughout the world. A calibrated and validated two-dimensional hydrodynamic model has been developed for the lower River (from River Mile 105, around New Orleans out to the -100 m depth in the Gulf of Mexico) that includes all of the lower River passes and many of the dynamic forcings from the Gulf. This model has been used to look at the flow distribution through the various passes and to investigate the potential impact of large-scale river diversion into the adjacent wetlands. In this talk, we will discuss the framework for incorporating model results under projected sea level rise conditions as well as more extreme flow conditions on future use and management of the River. Examples will be shown depicting the impact on flow distribution through the passes and other uncontrolled sections of the lower River, salt water migration, and the effectiveness of river diversions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMEP21C1855X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMEP21C1855X"><span>What would happen if the Mississippi River changed its course to the Atchafalaya?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Y. J.</p> <p>2017-12-01</p> <p>The Mississippi River Delta faces an uncertain future as sea level keeps rising while the land continues to subside. In its latest Master Plan draft of 2017, the Louisiana Coastal Protection and Restoration Authority has outlined a $50 billion investment for 120 projects designed to build and maintain coastal Louisiana. These projects are all developed under the assumption that the Mississippi River (MR) would remain on its current course, which is artificially maintained through a control structure built in 1963 (also known as the Old River Control Structure, or ORCS) after it was realized that the river attempted to change its course back to its old river channel - the Atchafalaya River (AR). Since the ORCS is in operation of controlling only about 25% of the MR flow into the AR, little attention has been paid to the importance of possible riverbed changes downstream the avulsion node on the MR course switch. As one of the largest alluvial river in the world, the MR avulsed every 1,000-1,500 years in the past. Alluvial rivers avulse when two conditions are met: a sufficient in-channel aggradation and a major flood. In our ongoing study on sediment transport and channel morphology of the lower Mississippi River, we found that the first 30-mile reach downstream the ORCS has been experiencing rapid bed aggradation and channel narrowing in the past three decades. A mega flood could be a triggering point to overpower the man-made ORCS and allow the river abandon its current channel - the MR main stem. This is not a desirable path; however, nature has its own mechanism of choosing river flows, which do not bow to our expectation. The Missisippi River's flow is projected to increase in the future as global temperature continues to rise and hydrologic cycle intensifies. Additionally, rapid urbanization in the river basin will create conditions that foster the emergence of mega floods. It would be impractical to spend considerable resources for a river delta without assessing the future avulsion risk of the river upstream. My presentation will discuss the possibility of a Mississippi River avulsion, its consequences, as well as what assessment data we need to develop rational strategies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MS%26E..245b2078G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MS%26E..245b2078G"><span>Numerical Model of Transitory Flood Flow in 2005 on River Timis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ghitescu, Marie-Alice; Lazar, Gheorghe; Titus Constantin, Albert; Nicoara, Serban-Vlad</p> <p>2017-10-01</p> <p>The paper presents numerical modelling of fluid flow transiting on the Timis River, downstream Lugoj section - N.H. COSTEIU, the occurrence of accidental flood waves from 4 April to 11 April 2005. Numerical simulation aims to estimate water levels on the route pattern on some areas and areas associated respectively floodplain adjacent construction site on the right bank of Timis river, on existing conditions in 2005. The model simulation from 2005 flood event shows that the model can be used for future inundation studies in this locality.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/5224223','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/5224223"><span>Proposal for adaptive management to conserve biotic integrity in a regulated segment of the Tallapoosa River, Alabama, U.S.A</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Irwin, Elise R.; Freeman, Mary C.</p> <p>2002-01-01</p> <p>Conserving river biota will require innovative approaches that foster and utilize scientific understanding of ecosystem responses to alternative river-management scenarios. We describe ecological and societal issues involved in flow management of a section of the Tallapoosa River (Alabama, U.S.A.) in which a species-rich native fauna is adversely affected by flow alteration by an upstream hydropower dam. We hypothesize that depleted Iow flows, flow instability and thermal alteration resulting from pulsed flow releases at the hydropower dam are most responsible for changes in the Tallapoosa River biota. However, existing data are insufficient to prescribe with certainty minimum flow levels or the frequency and duration of stable flow periods that would be necessary or sufficient to protect riverine biotic integrity. Rather than negotiate a specific change in the flow regime, we propose that stakeholders--including management agencies, the power utility, and river advocates--engage in a process of adaptive-flow management. This process would require that stakeholders (1) develop and agree to management objectives; (2) model hypothesized relations between dam operations and management objectives; (3) implement a change in dam operations; and (4) evaluate biological responses and other stakeholder benefits through an externally reviewed monitoring program. Models would be updated with monitoring data and stakeholders would agree to further modify flow regimes as necessary to achieve management objectives. A primary obstacle to adaptive management will be a perceived uncertainty of future costs for the power utility and other stakeholders. However, an adaptive, iterative approach offers the best opportunity for improving flow regimes for native biota while gaining information critical to guiding management decisions in other flow-regulated rivers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1914719Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1914719Z"><span>KLIMOPASS: Water-use conflicts during periods of low flow - a stakeholder analysis of the rivers Murg and Kocher in Baden-Wuerttemberg and sustainable recommendations for action</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zeitler, Florian; Dotterweich, Markus; Rothstein, Benno</p> <p>2017-04-01</p> <p>The 2003 and 2015 occurring heatwaves in Central Europe demonstrated on how dangerous long-lasting droughts and water stress can be for nature, people and companies relying on water. Climate change will increase the chance of low flow events along rivers in Baden-Wuerttemberg in the future leading to possible water-use conflicts amongst the users. This KLIMOPASS project focuses on the identification of existing and potential occurring conflicts of usage and interest for water resources. The main research concentrates on two exemplary river basins in Baden-Wuerttemberg (the Murg and the Kocher River) including all involved stakeholders and sectors (hydropower, agriculture, industry, sewage plants, ecology, tourism etc.). With the examples of the two rivers, the identification of conflicts, possible strategies for solutions and recommendations for action during current and future events of low flow have been researched. Quantitative and qualitative surveys, interviews, excursions and workshops have been conducted to analyse the stakeholder's potential for conflict. For this process it is necessary to equally consider all economic, societal and ecological interests and include all relevant stakeholders in the participatory process. According to the results, water related conflicts are not present in all sectors, but rather exclusive to certain sectors. Furthermore, these sectors are in conflict with more than one stakeholder group at the same time. In contrast, other users have not experienced any water related conflicts yet. Moreover, it is noticeable that conflicts in water use are only partly caused due to low flow events: regarding both rivers, low flow events are not only related to natural causes but particularly to anthropogenic influences.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2008/5143/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2008/5143/"><span>Simulation of Ground-Water Flow and Effects of Ground-Water Irrigation on Base Flow in the Elkhorn and Loup River Basins, Nebraska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Peterson, Steven M.; Stanton, Jennifer S.; Saunders, Amanda T.; Bradley, Jesse R.</p> <p>2008-01-01</p> <p>Irrigated agriculture is vital to the livelihood of communities in the Elkhorn and Loup River Basins in Nebraska, and ground water is used to irrigate most of the cropland. Concerns about the sustainability of ground-water and surface-water resources have prompted State and regional agencies to evaluate the cumulative effects of ground-water irrigation in this area. To facilitate understanding of the effects of ground-water irrigation, a numerical computer model was developed to simulate ground-water flow and assess the effects of ground-water irrigation (including ground-water withdrawals, hereinafter referred to as pumpage, and enhanced recharge) on stream base flow. The study area covers approximately 30,800 square miles, and includes the Elkhorn River Basin upstream from Norfolk, Nebraska, and the Loup River Basin upstream from Columbus, Nebraska. The water-table aquifer consists of Quaternary-age sands and gravels and Tertiary-age silts, sands, and gravels. The simulation was constructed using one layer with 2-mile by 2-mile cell size. Simulations were constructed to represent the ground-water system before 1940 and from 1940 through 2005, and to simulate hypothetical conditions from 2006 through 2045 or 2055. The first simulation represents steady-state conditions of the system before anthropogenic effects, and then simulates the effects of early surface-water development activities and recharge of water leaking from canals during 1895 to 1940. The first simulation ends at 1940 because before that time, very little pumpage for irrigation occurred, but after that time it became increasingly commonplace. The pre-1940 simulation was calibrated against measured water levels and estimated long-term base flow, and the 1940 through 2005 simulation was calibrated against measured water-level changes and estimated long-term base flow. The calibrated 1940 through 2005 simulation was used as the basis for analyzing hypothetical scenarios to evaluate the effects of ground-water irrigation on stream base flow for 1940 through 2005 and for 2006 through 2045. Simulated base flows were compared for scenarios that alternately did or did not include a representation of the effects of ground-water irrigation. The difference between simulated base flows for the two scenarios represents the predicted effects of ground-water irrigation on base flow. Comparison of base flows between simulations with ground-water irrigation and no ground-water irrigation indicated that ground-water irrigation has cumulatively reduced streamflows from 1940 through 2005 by 888,000 acre-feet in the Elkhorn River Basin and by 2,273,000 acre-feet in the Loup River Basin. Generally, predicted cumulative effects of ground-water irrigation on base flow were 5 to 10 times larger from 2006 through 2045 than from 1940 through 2005, and were 7,678,000 acre-feet for the Elkhorn River Basin and 14,784,000 acre-feet for the Loup River Basin. The calibrated simulation also was used to estimate base-flow depletion as a percentage of pumping volumes for a 50-year future time period, because base-flow depletion percentages are used to guide the placement of management boundaries in Nebraska. Mapped results of the base-flow depletion analysis conducted for most of the interior of the study area indicated that pumpage of one additional theoretical well simulated for a future 50-year period generally would result in more than 80 percent depletion when it was located close to the stream, except in areas where depletion was partly offset by reduced ground-water discharge to evapotranspiration in wetland areas. In many areas, depletion for the 50-year future period composed greater than 10 percent of the pumped water volume for theoretical wells placed less than 7 or 8 miles from the stream, though considerable variations existed because of the heterogeneity of the natural system represented in the simulation. For a few streams, predicted future simulated base flows dec</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25692851','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25692851"><span>Dynamic modeling of the Ganga river system: impacts of future climate and socio-economic change on flows and nitrogen fluxes in India and Bangladesh.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Whitehead, P G; Sarkar, S; Jin, L; Futter, M N; Caesar, J; Barbour, E; Butterfield, D; Sinha, R; Nicholls, R; Hutton, C; Leckie, H D</p> <p>2015-06-01</p> <p>This study investigates the potential impacts of future climate and socio-economic change on the flow and nitrogen fluxes of the Ganga river system. This is the first basin scale water quality study for the Ganga considering climate change at 25 km resolution together with socio-economic scenarios. The revised dynamic, process-based INCA model was used to simulate hydrology and water quality within the complex multi-branched river basins. All climate realizations utilized in the study predict increases in temperature and rainfall by the 2050s with significant increase by the 2090s. These changes generate associated increases in monsoon flows and increased availability of water for groundwater recharge and irrigation, but also more frequent flooding. Decreased concentrations of nitrate and ammonia are expected due to increased dilution. Different future socio-economic scenarios were found to have a significant impact on water quality at the downstream end of the Ganga. A less sustainable future resulted in a deterioration of water quality due to the pressures from higher population growth, land use change, increased sewage treatment discharges, enhanced atmospheric nitrogen deposition, and water abstraction. However, water quality was found to improve under a more sustainable strategy as envisaged in the Ganga clean-up plan.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H41G1454S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H41G1454S"><span>Mega drought in the Colorado River Basin, water supply, and adaptive scenario planning for the Phoenix Metropolitan Area; simulations using WaterSim 5.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sampson, D. A.</p> <p>2015-12-01</p> <p>The Decision Center for a Desert City (DCDC), a boundary organization, bridges science and policy (to foster knowledge-based decision making); we study how decisions are made in the face of uncertainty. Our water policy and management model for the Phoenix Metropolitan Area (hereafter "Phoenix"), termed WaterSim, represents one such bridging mechanism. We evaluated the effect of varying the length of drought on water availability for Phoenix. We examined droughts (starting in 2000) lasting 15, 25, and 50 years. We picked a 60-year window of runoff estimates from the paleo reconstruction data for the Colorado River (CO) (1121 through 1180 A.D.), and the two local rivers (1391 through 1450 A.D.), and assumed that the proportional difference in median flow between these periods and the long-term record represented an estimate of potential drought reductions on river flows. This resulted in a 12%, and 19% reduction in flows for the CO River and the Salt-Verde (SV) Rivers, respectively. WaterSim uses 30-year trace periods from the historical flow records to simulate river flow for future projections. We used each 30-year trace from the historical record (1906 to present, CO River; 1945 to present SV Rivers) , and default settings, to simulate 60 year projections of Lake Mead elevation and the accompanying Colorado River water shortages to Phoenix. Overall, elevations for Lake Mead fell below the 1st shortage sharing tier (1075 ft) in 83% of the simulations; 74% of the simulations fell below the 2nd tier (1050 ft), and 64% fell below the 3rd (1025 ft). Length of drought, however, determined the shortage tiers met. Median elevations for droughts ending in 2015, 2025, and 2050 were 1036, 1019, and 967 feet msl, respectively. We present the plausible water futures with adaptive anticipatory scenario planning for the projected reductions in surface water availability to demonstrate decision points for water conservation measures to effectively manage shortage conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70142978','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70142978"><span>Modeled intermittency risk for small streams in the Upper Colorado River Basin under climate change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Reynolds, Lindsay V.; Shafroth, Patrick B.; Poff, N. LeRoy</p> <p>2015-01-01</p> <p>Longer, drier summers projected for arid and semi-arid regions of western North America under climate change are likely to have enormous consequences for water resources and river-dependent ecosystems. Many climate change scenarios for this region involve decreases in mean annual streamflow, late summer precipitation and late-summer streamflow in the coming decades. Intermittent streams are already common in this region, and it is likely that minimum flows will decrease and some perennial streams will shift to intermittent flow under climate-driven changes in timing and magnitude of precipitation and runoff, combined with increases in temperature. To understand current intermittency among streams and analyze the potential for streams to shift from perennial to intermittent under a warmer climate, we analyzed historic flow records from streams in the Upper Colorado River Basin (UCRB). Approximately two-thirds of 115 gaged stream reaches included in our analysis are currently perennial and the rest have some degree of intermittency. Dry years with combinations of high temperatures and low precipitation were associated with more zero-flow days. Mean annual flow was positively related to minimum flows, suggesting that potential future declines in mean annual flows will correspond with declines in minimum flows. The most important landscape variables for predicting low flow metrics were precipitation, percent snow, potential evapotranspiration, soils, and drainage area. Perennial streams in the UCRB that have high minimum-flow variability and low mean flows are likely to be most susceptible to increasing streamflow intermittency in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70039557','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70039557"><span>National wild and scenic rivers system, January 2000</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>,; ,; ,; ,; ,</p> <p>2000-01-01</p> <p>The National Wild and Scenic Rivers System was created by Congress in 1968 (Public Law 90-542; 16 U.S.C 1271 et seq.) to preserve certain rivers with outstanding natural cultural, or recreational features in a free flowing condition for enjoyment of present and future generations. As of January 2000, the National System has grown from its initial eight components to a 156-river system with representation in 37 states.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2015/5093/sir20155093.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2015/5093/sir20155093.pdf"><span>Simulation of groundwater flow and analysis of the effects of water-management options in the North Platte Natural Resources District, Nebraska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Peterson, Steven M.; Flynn, Amanda T.; Vrabel, Joseph; Ryter, Derek W.</p> <p>2015-08-12</p> <p>The calibrated groundwater-flow model was used with the Groundwater-Management Process for the 2005 version of the U.S. Geological Survey modular three-dimensional groundwater model, MODFLOW–2005, to provide a tool for the NPNRD to better understand how water-management decisions could affect stream base flows of the North Platte River at Bridgeport, Nebr., streamgage in a future period from 2008 to 2019 under varying climatic conditions. The simulation-optimization model was constructed to analyze the maximum increase in simulated stream base flow that could be obtained with the minimum amount of reductions in groundwater withdrawals for irrigation. A second analysis extended the first to analyze the simulated base-flow benefit of groundwater withdrawals along with application of intentional recharge, that is, water from canals being released into rangeland areas with sandy soils. With optimized groundwater withdrawals and intentional recharge, the maximum simulated stream base flow was 15–23 cubic feet per second (ft3/s) greater than with no management at all, or 10–15 ft3/s larger than with managed groundwater withdrawals only. These results indicate not only the amount that simulated stream base flow can be increased by these management options, but also the locations where the management options provide the most or least benefit to the simulated stream base flow. For the analyses in this report, simulated base flow was best optimized by reductions in groundwater withdrawals north of the North Platte River and in the western half of the area. Intentional recharge sites selected by the optimization had a complex distribution but were more likely to be closer to the North Platte River or its tributaries. Future users of the simulation-optimization model will be able to modify the input files as to type, location, and timing of constraints, decision variables of groundwater withdrawals by zone, and other variables to explore other feasible management scenarios that may yield different increases in simulated future base flow of the North Platte River.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.H12B0987H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.H12B0987H"><span>Salinization Sources Along the Lower Jordan River Under Draught Conditions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holtzman, R.; Shavit, U.; Segal, M.; Vengosh, A.; Farber, E.; Gavrieli, I.</p> <p>2003-12-01</p> <p>The Lower Jordan River, once a flowing freshwater river, is suffering from an ongoing reduction of discharge and water quality. The river flows between the Sea of Galilee and the Dead Sea, an aerial distance of about 105 Km. The severe reduction is caused by an excessive exploitation of its sources and diversion of sewage and agricultural drainage into the river. The extreme low flows and low water quality threaten the natural existence of the river and its potential use for agriculture. In spite of its importance, little research has been done in the river. The objectives of the study were to measure the discharge and water composition along the river and to evaluate the main sources that control its flow and chemical characteristics. The hypothesis of the study was that interaction with subsurface flows significantly affects the river flow and chemical composition. The research is based on a detailed field study, which included flow rate measurements in the river and its tributaries, water sampling and analysis and mass balance calculations of water and solutes. A portable Acoustic Doppler Velocimeter (ADV) was used to measure velocities and bathymetry at different locations across the river sections. Due to accessibility constraints, a floating traverse construction, which enables the ADV's deployment from one bank of the river, was developed. It was found that flow rate ranges between 500-1,100 L/s in northern (upstream) sections and 300-1,650 L/s in the south. This low discharge represents a significant reduction from historical values and is lower than recent published estimations. This research represents base flows only, as the measurements were done during a period of two consecutive draught years. Calculated mass balance of water flows in the northern sections shows that the subsurface source contributes to the river around 200-670 L/s (30-80% of the river flow). Calculations of solute balance show that the subsurface flows add 20-50% of the mass of solutes (e.g. Sulfate) that flows in the river. The assumption of a hydraulic gradient that points at inflows from subsurface flows is encouraged by high water levels measured in nearby piezometers. Possible natural subsurface sources include shallow groundwater or rising of water from deep formations. The existence of adjacent thermal wells strengthens the reasonability of such water rise. Possible anthropogenic sources include return flows and effluents. The results are consistent and agree with the geochemical and isotopic analyses. It is concluded that the impact of the subsurface component on the Jordan River is significant and must be taken into consideration, for future water management schemes and implementation of the Peace Treaty between Israel and Jordan.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70018499','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70018499"><span>Predictive techniques for river channel evolution and maintenance</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nelson, J.M.</p> <p>1996-01-01</p> <p>Predicting changes in alluvial channel morphology associated with anthropogenic and natural changes in flow and/or sediment supply is a critical part of the management of riverine systems. Over the past few years, advances in the understanding of the physics of sediment transport in conjunction with rapidly increasing capabilities in computational fluid dynamics have yielded now approaches to problems in river mechanics. Techniques appropriate for length scales ranging from reaches to bars and bedforms are described here. Examples of the use of these computational approaches are discussed for three cases: (1) the design of diversion scenarios that maintain channel morphology in steep cobble-bedded channels in Colorado, (2) determination of channel maintenance flows for the preservation of channel islands in the Snake River in Idaho, and (3) prediction of the temporal evolution of deposits in lateral separation zones for future assessment of the impacts of various dam release scenarios on lateral separation deposits in the Colorado River in Grand Canyon. With continued development of their scientific and technical components, the methodologies described here can provide powerful tools for the management of river environments in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.acs.org/doi/abs/10.1021/es404760t','USGSPUBS'); return false;" href="http://pubs.acs.org/doi/abs/10.1021/es404760t"><span>Assessment of floodplain vulnerability during extreme Mississippi River flood 2011</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Goodwell, Allison E.; Zhu, Zhenduo; Dutta, Debsunder; Greenberg, Jonathan A.; Kumar, Praveen; Garcia, Marcelo H.; Rhoads, Bruce L.; Holmes, Robert R.; Parker, Gary; Berretta, David P.; Jacobson, Robert B.</p> <p>2014-01-01</p> <p>Regional change in the variability and magnitude of flooding could be a major consequence of future global climate change. Extreme floods have the capacity to rapidly transform landscapes and expose landscape vulnerabilities through highly variable spatial patterns of inundation, erosion, and deposition. We use the historic activation of the Birds Point-New Madrid Floodway during the Mississippi and Ohio River Flooding of 2011 as a scientifically unique stress experiment to analyze indicators of floodplain vulnerability. We use pre- and postflood airborne Light Detection and Ranging data sets to locate erosional and depositional hotspots over the 540 km2 agricultural Floodway. While riparian vegetation between the river and the main levee breach likely prevented widespread deposition, localized scour and deposition occurred near the levee breaches. Eroded gullies nearly 1 km in length were observed at a low ridge of a relict meander scar of the Mississippi River. Our flow modeling and spatial mapping analysis attributes this vulnerability to a combination of erodible soils, flow acceleration associated with legacy fluvial landforms, and a lack of woody vegetation to anchor soil and enhance flow resistance. Results from this study could guide future mitigation and adaptation measures in cases of extreme flooding.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24512322','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24512322"><span>Assessment of floodplain vulnerability during extreme Mississippi River flood 2011.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Goodwell, Allison E; Zhu, Zhenduo; Dutta, Debsunder; Greenberg, Jonathan A; Kumar, Praveen; Garcia, Marcelo H; Rhoads, Bruce L; Holmes, Robert R; Parker, Gary; Berretta, David P; Jacobson, Robert B</p> <p>2014-01-01</p> <p>Regional change in the variability and magnitude of flooding could be a major consequence of future global climate change. Extreme floods have the capacity to rapidly transform landscapes and expose landscape vulnerabilities through highly variable spatial patterns of inundation, erosion, and deposition. We use the historic activation of the Birds Point-New Madrid Floodway during the Mississippi and Ohio River Flooding of 2011 as a scientifically unique stress experiment to analyze indicators of floodplain vulnerability. We use pre- and postflood airborne Light Detection and Ranging data sets to locate erosional and depositional hotspots over the 540 km(2) agricultural Floodway. While riparian vegetation between the river and the main levee breach likely prevented widespread deposition, localized scour and deposition occurred near the levee breaches. Eroded gullies nearly 1 km in length were observed at a low ridge of a relict meander scar of the Mississippi River. Our flow modeling and spatial mapping analysis attributes this vulnerability to a combination of erodible soils, flow acceleration associated with legacy fluvial landforms, and a lack of woody vegetation to anchor soil and enhance flow resistance. Results from this study could guide future mitigation and adaptation measures in cases of extreme flooding.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17428594','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17428594"><span>Future climate scenarios and rainfall--runoff modelling in the Upper Gallego catchment (Spain).</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bürger, C M; Kolditz, O; Fowler, H J; Blenkinsop, S</p> <p>2007-08-01</p> <p>Global climate change may have large impacts on water supplies, drought or flood frequencies and magnitudes in local and regional hydrologic systems. Water authorities therefore rely on computer models for quantitative impact prediction. In this study we present kernel-based learning machine river flow models for the Upper Gallego catchment of the Ebro basin. Different learning machines were calibrated using daily gauge data. The models posed two major challenges: (1) estimation of the rainfall-runoff transfer function from the available time series is complicated by anthropogenic regulation and mountainous terrain and (2) the river flow model is weak when only climate data are used, but additional antecedent flow data seemed to lead to delayed peak flow estimation. These types of models, together with the presented downscaled climate scenarios, can be used for climate change impact assessment in the Gallego, which is important for the future management of the system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2016/1146/ofr20161146.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2016/1146/ofr20161146.pdf"><span>Modeling water quality, temperature, and flow in Link River, south-central Oregon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sullivan, Annett B.; Rounds, Stewart A.</p> <p>2016-09-09</p> <p>The 2.1-km (1.3-mi) Link River connects Upper Klamath Lake to the Klamath River in south-central Oregon. A CE-QUAL-W2 flow and water-quality model of Link River was developed to provide a connection between an existing model of the upper Klamath River and any existing or future models of Upper Klamath Lake. Water-quality sampling at six locations in Link River was done during 2013–15 to support model development and to provide a better understanding of instream biogeochemical processes. The short reach and high velocities in Link River resulted in fast travel times and limited water-quality transformations, except for dissolved oxygen. Reaeration through the reach, especially at the falls in Link River, was particularly important in moderating dissolved oxygen concentrations that at times entered the reach at Link River Dam with marked supersaturation or subsaturation. This reaeration resulted in concentrations closer to saturation downstream at the mouth of Link River.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H31H0734F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H31H0734F"><span>Impact of Climate Change on Mercury Transport along the Carson River-Lahontan Reservoir System</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flickinger, A.; Carroll, R. W. H.; Warwick, J. J.; Schumer, R.</p> <p>2014-12-01</p> <p>Historic mining practices have left the Carson River and Lahontan Reservoir (CRLR) system contaminated with high levels of mercury (Hg). Hg levels in Lahontan Reservoir planktivorous and predatory fish exceed federal consumption limits. Inputs of Hg to the system are mainly a result of erosion during high flow and diffusion from sediment during low flow, and the relationships between streamflow and both mercury transport and bioaccumulation are non-linear. The United States Bureau of Reclamation has produced future streamflow estimates for 2000-2099 using 112 CMIP3 climate projections and the Variable Infiltration Capacity (VIC) model. VIC results suggest that the hydrology of the system is likely to experience higher frequencies of both high and low extreme flows, and the monthly averages of future flows are expected to be higher in the winter and lower in the summer compared to observed flows. VIC daily streamflow estimates are biased-corrected using an empirical cumulative distribution function to match observed data over the historic period of 1950-1999. Future reservoir stage and outflows are modeled assuming reservoir operations are a function of river/canal inflows, previous reservoir stage and downstream agricultural demands. VIC and reservoir flows drive the CRLR Hg transport model (RIVMOD, WASP5, and MERC4). Daily output for both total and dissolved inorganic Hg and methylmercury (MeHg) are averaged at the decadal timescale to assess changes and uncertainty in predicted spatial and temporal Hg species water column concentrations as a function of altered hydrology with respect to changing climate. Future research will use CRLR output in a bioenergetics and Hg mass balance model for Sacramento blackfish (Orthodon microlepidotus), a filter feeding cyprinid found in Lahontan Reservoir. These future simulations will help to assess possible changes in ecosystem health with respect to hydrologic conditions and associated changes to Hg transport.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/890730','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/890730"><span>Past, Present, Future Erosion at Locke Island</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Bjornstad, Bruce N.</p> <p>2006-08-08</p> <p>This report describes and documents the erosion that has occurred along the northeast side of Locke Island over the last 10 to 20 years. The principal cause of this erosion is the massive Locke Island landslide complex opposite the Columbia River along the White Bluffs, which constricts the flow of the river and deflects the river's thalweg southward against the island.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.cerc.usgs.gov/rss/visualize/','USGSPUBS'); return false;" href="http://www.cerc.usgs.gov/rss/visualize/"><span>Visualization of Flow Alternatives, Lower Missouri River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jacobson, Robert B.; Heuser, Jeanne</p> <p>2002-01-01</p> <p>Background The U.S. Army Corps of Engineers (COE) 'Missouri River Master Water Control Manual' (Master Manual) review has resulted in consideration of many flow alternatives for managing the water in the river (COE, 2001; 1998a). The purpose of this report is to present flow-management alternative model results in a way that can be easily visualized and understood. This report was updated in October 2001 to focus on the specific flow-management alternatives presented by the COE in the 'Master Manual Revised Draft Environmental Impact Statement' (RDEIS; COE, 2001). The original version (February 2000) is available by clicking here. The COE, U.S. Fish and Wildlife Service (FWS), Missouri River states, and Missouri River basin tribes have been participating in discussions concerning water management of the Missouri River mainstem reservoir system (MRMRS), the Missouri River Bank Stabilization and Navigation Project, and the Kansas River reservoir system since 1986. These discussions include general input to the revision of the Master Manual as well as formal consultation under Section 7 of the Endangered Species Act. In 2000, the FWS issued a Biological Opinion that prescribed changes to reservoir management on the Missouri River that were believed to be necessary to preclude jeopardy to three endangered species, the pallid sturgeon, piping plover, and interior least tern (USFWS, 2000). The combined Missouri River system is large and complex, including many reservoirs, control structures, and free-flowing reaches extending over a broad region. The ability to assess future impacts of altered management scenarios necessarily involves complex, computational models that attempt to integrate physical, chemical, biological, and economic effects. Graphical visualization of the model output is intended to improve understanding of the differences among flow-management alternatives.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70034383','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70034383"><span>Characterizing a December 2005 density current event in the Chicago River, Chicago, Illinois</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Garcia, C.M.; Jackson, P.R.; Oberg, K.A.; Johnson, K.K.; Garcia, M.H.</p> <p>2007-01-01</p> <p>During the winter months, the Chicago River in Chicago, Illinois is subject to bi-directional flows, and density currents are thought to be responsible for these flow variations. This paper presents detailed field measurements using three acoustic Doppler current profiler instruments and simultaneous water-quality measurements made during December 2005. Observations indicate that the formation of density currents within the Chicago River and density differences are mostly due to salinity differences between the North Branch and the main stem of the Chicago River, whereas temperature difference does not appreciably affect the creation of density currents. Sources of higher water temperature, conductivity, and salinity values should be addressed in future studies. ?? 2007 ASCE.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27887836','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27887836"><span>Modelling white-water rafting suitability in a hydropower regulated Alpine River.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Carolli, Mauro; Zolezzi, Guido; Geneletti, Davide; Siviglia, Annunziato; Carolli, Fabiano; Cainelli, Oscar</p> <p>2017-02-01</p> <p>Cultural and recreational river ecosystem services and their relations with the flow regime are still poorly investigated. We develop a modelling-based approach to assess recreational flow requirements and the spatially distributed river suitability for white-water rafting, a typical service offered by mountain streams, with potential conflicts of interest with hydropower regulation. The approach is based on the principles of habitat suitability modelling using water depth as the main attribute, with preference curves defined through interviews with local rafting guides. The methodology allows to compute streamflow thresholds for conditions of suitability and optimality of a river reach in relation to rafting. Rafting suitability response to past, present and future flow management scenarios can be predicted on the basis of a hydrological model, which is incorporated in the methodology and is able to account for anthropic effects. Rafting suitability is expressed through a novel metric, the "Rafting hydro-suitability index" (RHSI) which quantifies the cumulative duration of suitable and optimal conditions for rafting. The approach is applied on the Noce River (NE Italy), an Alpine River regulated by hydropower production and affected by hydropeaking, which influences suitability at a sub-daily scale. A dedicated algorithm is developed within the hydrological model to resemble hydropeaking conditions with daily flow data. In the Noce River, peak flows associated with hydropeaking support rafting activities in late summer, highlighting the dual nature of hydropeaking in regulated rivers. Rafting suitability is slightly reduced under present, hydropower-regulated flow conditions compared to an idealized flow regime characterised by no water abstractions. Localized water abstractions for small, run-of-the-river hydropower plants are predicted to negatively affect rafting suitability. The proposed methodology can be extended to support decision making for flow management in hydropower regulated streams, as it has the potential to quantify the response of different ecosystem services to flow regulation. Copyright © 2016 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.H14E..02H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.H14E..02H"><span>Satellite Altimetry based River Forecasting of Transboundary Flow</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hossain, F.; Siddique-E-Akbor, A.; Lee, H.; Shum, C.; Biancamaria, S.</p> <p>2012-12-01</p> <p>Forecasting of this transboundary flow in downstream nations however remains notoriously difficult due to the lack of basin-wide in-situ hydrologic measurements or its real-time sharing among nations. In addition, human regulation of upstream flow through diversion projects and dams, make hydrologic models less effective for forecasting on their own. Using the Ganges-Brahmaputra (GB) basin as an example, this study assesses the feasibility of using JASON-2 satellite altimetry for forecasting such transboundary flow at locations further inside the downstream nation of Bangladesh by propagating forecasts derived from upstream (Indian) locations through a hydrodynamic river model. The 5-day forecast of river levels at upstream boundary points inside Bangladesh are used to initialize daily simulation of the hydrodynamic river model and yield the 5-day forecast river level further downstream inside Bangladesh. The forecast river levels are then compared with the 5-day-later "now cast" simulation by the river model based on in-situ river level at the upstream boundary points in Bangladesh. Future directions for satellite-based forecasting of flow are also briefly overviewed.round tracks or virtual stations of JASON-2 (J2) altimeter over the GB basin shown in yellow lines. The locations where the track crosses a river and used for deriving forecasting rating curves is shown with a circle and station number (magenta- Brahmaputra basin; blue - Ganges basin). Circles without a station number represent the broader view of sampling by JASON-2 if all the ground tracks on main stem rivers and neighboring tributaries of Ganges and Brahmaputra are considered.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2014/5115/pdf/sir2014-5115.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2014/5115/pdf/sir2014-5115.pdf"><span>Streamflow statistics for unregulated and regulated conditions for selected locations on the Upper Yellowstone and Bighorn Rivers, Montana and Wyoming, 1928-2002</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chase, Katherine J.</p> <p>2014-01-01</p> <p>Major floods in 1996 and 1997 intensified public debate about the effects of human activities on the Yellowstone River. In 1999, the Yellowstone River Conservation District Council was formed to address conservation issues on the river. The Yellowstone River Conservation District Council partnered with the U.S. Army Corps of Engineers to carry out a cumulative effects study on the main stem of the Yellowstone River. The cumulative effects study is intended to provide a basis for future management decisions within the watershed. Streamflow statistics, such as flow-frequency data calculated for unregulated and regulated streamflow conditions, are a necessary component of the cumulative effects study. The U.S. Geological Survey, in cooperation with the Yellowstone River Conservation District Council and the U.S. Army Corps of Engineers, calculated low-flow frequency data and general monthly and annual statistics for unregulated and regulated streamflow conditions for the Upper Yellowstone and Bighorn Rivers for the 1928–2002 study period; these data are presented in this report. Unregulated streamflow represents flow conditions during the 1928–2002 study period if there had been no water-resources development in the Yellowstone River Basin. Regulated streamflow represents estimates of flow conditions during the 1928–2002 study period if the level of water-resources development existing in 2002 was in place during the entire study period.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H21E1451H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H21E1451H"><span>Anticipating Central Asian Water Stress: Variation in River Flow Dependency on Melt Waters from Alpine to Plains in the Remote Tien Shan Range, Kyrgyzstan Using a Rapid Hydro Assessment Methodology</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hill, A. F.; Wilson, A. M.; Williams, M. W.</p> <p>2016-12-01</p> <p>The future of mountain water resources in High Asia is of high interest to water managers, development organizations and policy makers given large populations downstream reliant on snow and ice sourced river flow. Together with historical and cultural divides among ex-Soviet republics, a lack of central water management following the Soviet break-up has led to water stress as trans-boundary waters weave through and along borders. New upstream hydropower development, a thirsty downstream agricultural sector and a shrinking Aral Sea has led to increasing tension in the region. Despite these pressures and in contrast to eastern High Asia's Himalayan basins (Ganges, Brahmaputra), little attention has been given to western High Asia draining the Pamir and Tien Shan ranges (Syr Darya and Amu Darya basins) to better understand the hydrology of this vast and remote area. Difficult access and challenging terrain exacerbate challenges to working in this remote mountain region. As part of the Contributions to High Asia Runoff from Ice and Snow (CHARIS) project, we asked how does river flow source water composition change over an alpine-to-plains domain of Kyrgyzstan's Naryn River in the Syr Darya basin? In addition, what may the future hold for river flow in Central Asia given the differing responses of snow and ice to climate changes? Utilizing a Rapid Hydrologic Assessment methodology including a suite of pre-field mapping techniques we collected in situ water chemistry data at targeted, remote mountain sites over 450km of the Naryn River over an elevation gradient from glacial headwaters to the lower lying areas - places where people, hydropower and agriculture utilize water. Chemical and isotope tracers were used to separate stream flow to understand relative dependency on melt waters as the river moves downstream from glaciers and snow covered areas. This case study demonstrates a technique to acquire field data over large scales in remote regions that facilitates regional basin wide hydrologic characterization. The arid hydro-climatology of the Naryn basin also serves as an important comparison to the monsoon-dominated eastern Himalaya studies, thereby providing bookends to anticipating possible hydrologic futures across the High Asian mountain arc.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23787302','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23787302"><span>Impact of urban WWTP and CSO fluxes on river peak flow extremes under current and future climate conditions.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Keupers, Ingrid; Willems, Patrick</p> <p>2013-01-01</p> <p>The impact of urban water fluxes on the river system outflow of the Grote Nete catchment (Belgium) was studied. First the impact of the Waste Water Treatment Plant (WWTP) and the Combined Sewer Overflow (CSO) outflows on the river system for the current climatic conditions was determined by simulating the urban fluxes as point sources in a detailed, hydrodynamic river model. Comparison was made of the simulation results on peak flow extremes with and without the urban point sources. In a second step, the impact of climate change scenarios on the urban fluxes and the consequent impacts on the river flow extremes were studied. It is shown that the change in the 10-year return period hourly peak flow discharge due to climate change (-14% to +45%) was in the same order of magnitude as the change due to the urban fluxes (+5%) in current climate conditions. Different climate change scenarios do not change the impact of the urban fluxes much except for the climate scenario that involves a strong increase in rainfall extremes in summer. This scenario leads to a strong increase of the impact of the urban fluxes on the river system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H33C1612H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H33C1612H"><span>Scaling Hydrologic Exchange Flows and Biogeochemical Reactions from Bedforms to Basins</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harvey, J. W.; Gomez-Velez, J. D.</p> <p>2015-12-01</p> <p>River water moves in and out of the main channel along pathways that are perpendicular to the channel's main axis that flow across or beneath the ground surface. These hydrologic exchange flows (HEFs) are difficult to measure, yet no less important than a river's downstream flow, or exchanges with the atmosphere and deeper groundwater (Harvey and Gooseff, 2015, WRR). There are very few comprehensive investigations of exchange fluxes to understand patterns with river size and relative importance of specific types of exchanges. We used the physically based model NEXSS to simulate multiple scales of hyporheic flow and their cumulative effects on solute reaction in large basins (on the order of Chesapeake Bay basin or larger). Our goal was to explain where and when particular types of hyporheic flow are important in enhancing key biogeochemical reactions, such as organic carbon respiration and denitrification. Results demonstrate that hyporheic flux (expressed per unit area of streambed) varies surprisingly little across the continuum of first-order streams to eighth-order rivers, and vertical exchange beneath small bedforms dominates in comparison with lateral flow beneath gravel bars and meanders. Also, the river's entire volume is exchanged many times with hyporheic flow within a basin, and the turnover length (after one entire river volume is exchanged) is strongly influenced by hydrogeomorphic differences between physiographic regions as well as by river size. The cumulative effects on biogeochemical reactions were assessed using a the reaction significance factor, RSF, which computes the cumulative potential for hyporheic reactions using a dimensionless index that balances reaction progress in a single hyporheic flow path against overall processing efficiency of river turnover through hyporheic flow paths of that type. Reaction significance appears to be strongly dominated by hydrologic factors rather than biogeochemical factors, and seems to be dominated by vertical exchange beneath small bedforms throughout river networks. Future implementations of NEXSS will expand the model to consider flow variation and to consider HEFs beyond hyporheic flow to include exchange with marginal surface waters such as riparian wetlands, floodplains, and ponded water.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H43Q..07F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H43Q..07F"><span>The Science and Policy of the First Environmental Flows to the Colorado River Delta</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flessa, K. W.; Kendy, E.; Schlatter, K.</p> <p>2014-12-01</p> <p>The first transboundary flow of water for the environment was delivered to the Colorado River Delta in spring of 2014. This engineered mini-spring flood of 130 million cubic meters (105,000 acre-feet) was implemented as part of Minute 319, an addition to the 1944 U.S.-Mexico Water Treaty. Minute 319 is a temporary agreement, expiring in 2017. Teams of scientists from government agencies, universities, and environmental NGOs from both the U.S. and Mexico are measuring the surface flow rates, inundation, ground water recharge, ground water levels and subsurface flows, geomorphic change, recruitment, survival and health of vegetation, and avian response to the environmental flow. Monitoring includes on-the-ground observations and measurements and remote sensing. Surface water from the pulse flow reached restoration sites, prompted germination of both native and non-native vegetation, recharged groundwater and reached the Gulf of California - the first reconnection of the Colorado River and the sea in 16 years. People in local communities joyously welcomed the return of the river; extensive media coverage was overwhelmingly positive - despite widespread drought in the West. After about ten weeks, most of the pulse flow had infiltrated the subsurface, ponded in a few cut-off meanders, or run to the sea. The river no longer flows. Monitoring of seedling survival, groundwater, vegetation and wildlife will continue through 2017. Results of this landscape-scale experiment will play a role in negotiations to renew the agreement, help model and design future flows and guide the efficient use of water for restoration in semi-arid river systems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/10159425','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/10159425"><span>Interim Columbia and Snake rivers flow improvement measures for salmon: Final Supplemental Environmental Impact Statement (SEIS)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Not Available</p> <p>1993-03-01</p> <p>Public comments are sought on this final SEIS, which supplements the 1992 Columbia River Salmon Flow Measures Options Analysis (OA)/Environmental Impact Statement (EIS). The Corps of Engineers, in cooperation with the Bonneville Power Administration and the Bureau of Reclamation proposes five alternatives to improve flows of water in the lower Columbia-Snake rivers in 1993 and future years to assist the migration of juvenile and adult anadromous fish past eight hydropower dams. These are: (1) Without Project (no action) Alternative, (2) the 1992 Operation, (3) the 1992 Operation with Libby/Hungry Horse Sensitivity, (4) a Modified 1992 Operation with Improvements to Salmonmore » Flows from Dworshak, and (5) a Modified 1992 Operation with Upper Snake Sensitivity. Alternative 4, Modified 1992 Operations, has been identified as the preferred alternative.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7533P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7533P"><span>Coupling climate and hydrological models to evaluate the impact of climate change on run of the river hydropower schemes from UK study sites</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pasten-Zapata, Ernesto; Jones, Julie; Moggridge, Helen</p> <p>2015-04-01</p> <p>As climate change is expected to generate variations on the Earth's precipitation and temperature, the water cycle will also experience changes. Consequently, water users will have to be prepared for possible changes in future water availability. The main objective of this research is to evaluate the impacts of climate change on river regimes and the implications to the operation and feasibility of run of the river hydropower schemes by analyzing four UK study sites. Run of the river schemes are selected for analysis due to their higher dependence to the available river flow volumes when compared to storage hydropower schemes that can rely on previously accumulated water volumes (linked to poster in session HS5.3). Global Climate Models (GCMs) represent the main tool to assess future climate change. In this research, Regional Climate Models (RCMs), which dynamically downscale GCM outputs providing higher resolutions, are used as starting point to evaluate climate change within the study catchments. RCM daily temperature and precipitation will be downscaled to an appropriate scale for impact studies and bias corrected using different statistical methods: linear scaling, local intensity scaling, power transformation, variance scaling and delta change correction. The downscaled variables will then be coupled to hydrological models that have been previously calibrated and validated against observed daily river flow data. The coupled hydrological and climate models will then be used to simulate historic river flows that are compared to daily observed values in order to evaluate the model accuracy. As this research will employ several different RCMs (from the EURO-CORDEX simulations), downscaling and bias correction methodologies, greenhouse emission scenarios and hydrological models, the uncertainty of each element will be estimated. According to their uncertainty magnitude, a prediction of the best downscaling approach (or approaches) is expected to be obtained. The current progress of the project will be presented along with the steps to be followed in the future.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70195226','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70195226"><span>Hydroclimatology of the Missouri River basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wise, Erika K.; Woodhouse, Connie A.; McCabe, Gregory; Pederson, Gregory T.; St. Jacques, Jeannine-Marie</p> <p>2018-01-01</p> <p>Despite the importance of the Missouri River for navigation, recreation, habitat, hydroelectric power, and agriculture, relatively little is known about the basic hydroclimatology of the Missouri River basin (MRB). This is of particular concern given the droughts and floods that have occurred over the past several decades and the potential future exacerbation of these extremes by climate change. Here, observed and modeled hydroclimatic data and estimated natural flow records in the MRB are used to 1) assess the major source regions of MRB flow, 2) describe the climatic controls on streamflow in the upper and lower basins , and 3) investigate trends over the instrumental period. Analyses indicate that 72% of MRB runoff is generated by the headwaters in the upper basin and by the lowest portion of the basin near the mouth. Spring precipitation and temperature and winter precipitation impacted by changes in zonal versus meridional flow from the Pacific Ocean play key roles in surface water supply variability in the upper basin. Lower basin flow is significantly correlated with precipitation in late spring and early summer, indicative of Atlantic-influenced circulation variability affecting the flow of moisture from the Gulf of Mexico. Although increases in precipitation in the lower basin are currently overriding the effects of warming temperatures on total MRB flow, the upper basin’s long-term trend toward decreasing flows, reduction in snow versus rain fraction, and warming spring temperatures suggest that the upper basin may less often provide important flow supplements to the lower basin in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/6165789-powder-river-outlook-stays-healthy','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6165789-powder-river-outlook-stays-healthy"><span>Powder River outlook stays healthy</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Stremel, K.</p> <p>1984-08-01</p> <p>Well drilling activity in Wyoming's Powder River Basin is discussed. Operators are taking advantage of favorable economic advantages to tap the area's multiple pay potential and challenge its high success rate reputation. A significant amount of exploration and development can be expected in the future due to the recent discovery of high-flowing wells.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012HESS...16.2839C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012HESS...16.2839C"><span>Impacts of impervious cover, water withdrawals, and climate change on river flows in the conterminous US</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caldwell, P. V.; Sun, G.; McNulty, S. G.; Cohen, E. C.; Moore Myers, J. A.</p> <p>2012-08-01</p> <p>Rivers are essential to aquatic ecosystem and societal sustainability, but are increasingly impacted by water withdrawals, land-use change, and climate change. The relative and cumulative effects of these stressors on continental river flows are relatively unknown. In this study, we used an integrated water balance and flow routing model to evaluate the impacts of impervious cover and water withdrawal on river flow across the conterminous US at the 8-digit Hydrologic Unit Code (HUC) watershed scale. We then estimated the impacts of projected change in withdrawals, impervious cover, and climate under the B1 "Low" and A2 "High" emission scenarios on river flows by 2060. Our results suggest that compared to no impervious cover, 2010 levels of impervious cover increased river flows by 9.9% on average with larger impacts in and downstream of major metropolitan areas. In contrast, compared to no water withdrawals, 2005 withdrawals decreased river flows by 1.4% on average with larger impacts in heavily irrigated arid regions of Western US. By 2060, impacts of climate change were predicted to overwhelm the potential gain in river flow due to future changes in impervious cover and add to the potential reduction in river flows from withdrawals, decreasing mean annual river flows from 2010 levels by 16% on average. However, increases in impervious cover by 2060 may offset the impact of climate change during the growing season in some watersheds. Large water withdrawals will aggravate the predicted impact of climate change on river flows, particularly in the Western US. Predicted ecohydrological impacts of land cover, water withdrawal, and climate change will likely include alteration of the terrestrial water balance, stream channel habitat, riparian and aquatic community structure in snow-dominated basins, and fish and mussel extirpations in heavily impacted watersheds. These changes may also require new infrastructure to support increasing anthropogenic demand for water, relocation of agricultural production, and/or water conservation measures. Given that the impacts of land use, withdrawals and climate may be either additive or offsetting in different magnitudes, integrated and spatially explicit modeling and management approaches are necessary to effectively manage water resources for aquatic life and human use in the face of global change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H43D1671W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H43D1671W"><span>Climate controls on streamflow variability in the Missouri River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wise, E.; Woodhouse, C. A.; McCabe, G. J., Jr.; Pederson, G. T.; St-Jacques, J. M.</p> <p>2017-12-01</p> <p>The Missouri River's hydroclimatic variability presents a challenge for water managers, who must balance many competing demands on the system. Water resources in the Missouri River Basin (MRB) have increasingly been challenged by the droughts and floods that have occurred over the past several decades and the potential future exacerbation of these extremes by climate change. Here, we use observed and modeled hydroclimatic data and estimated natural flow records to describe the climatic controls on streamflow in the upper and lower portions of the MRB, examine atmospheric and oceanic patterns associated with high- and low-flow years, and investigate trends in climate and streamflow over the instrumental period. Results indicate that the two main source regions for total outflow, in the uppermost and lowermost parts of the basin, are under the influence of very different sets of climatic controls. Winter precipitation, impacted by changes in zonal versus meridional flow from the Pacific Ocean, as well as spring precipitation and temperature, play a key role in surface water supply variability in the upper basin. Lower basin flow is significantly correlated with precipitation in late spring and early summer, indicative of Atlantic-influenced circulation variability affecting the flow of moisture from the Gulf of Mexico. The upper basin, with decreasing snowpack and streamflow and warming spring temperatures, will be less likely to provide important flow supplements to the lower basin in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HESS...17.4555V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HESS...17.4555V"><span>One-way coupling of an integrated assessment model and a water resources model: evaluation and implications of future changes over the US Midwest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Voisin, N.; Liu, L.; Hejazi, M.; Tesfa, T.; Li, H.; Huang, M.; Liu, Y.; Leung, L. R.</p> <p>2013-11-01</p> <p>An integrated model is being developed to advance our understanding of the interactions between human activities, terrestrial system and water cycle, and to evaluate how system interactions will be affected by a changing climate at the regional scale. As a first step towards that goal, a global integrated assessment model, which includes a water-demand model driven by socioeconomics at regional and global scales, is coupled in a one-way fashion with a land surface hydrology-routing-water resources management model. To reconcile the scale differences between the models, a spatial and temporal disaggregation approach is developed to downscale the annual regional water demand simulations into a daily time step and subbasin representation. The model demonstrates reasonable ability to represent the historical flow regulation and water supply over the US Midwest (Missouri, Upper Mississippi, and Ohio river basins). Implications for future flow regulation, water supply, and supply deficit are investigated using climate change projections with the B1 and A2 emission scenarios, which affect both natural flow and water demand. Although natural flow is projected to increase under climate change in both the B1 and A2 scenarios, there is larger uncertainty in the changes of the regulated flow. Over the Ohio and Upper Mississippi river basins, changes in flow regulation are driven by the change in natural flow due to the limited storage capacity. However, both changes in flow and demand have effects on the Missouri River Basin summer regulated flow. Changes in demand are driven by socioeconomic factors, energy and food demands, global markets and prices with rainfed crop demand handled directly by the land surface modeling component. Even though most of the changes in supply deficit (unmet demand) and the actual supply (met demand) are driven primarily by the change in natural flow over the entire region, the integrated framework shows that supply deficit over the Missouri River Basin sees an increasing sensitivity to changes in demand in future periods. It further shows that the supply deficit is six times as sensitive as the actual supply to changes in flow and demand. A spatial analysis of the supply deficit demonstrates vulnerabilities of urban areas located along mainstream with limited storage.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JHyd..554..434Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JHyd..554..434Y"><span>Evaluation on uncertainty sources in projecting hydrological changes over the Xijiang River basin in South China</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yuan, Fei; Zhao, Chongxu; Jiang, Yong; Ren, Liliang; Shan, Hongcui; Zhang, Limin; Zhu, Yonghua; Chen, Tao; Jiang, Shanhu; Yang, Xiaoli; Shen, Hongren</p> <p>2017-11-01</p> <p>Projections of hydrological changes are associated with large uncertainties from different sources, which should be quantified for an effective implementation of water management policies adaptive to future climate change. In this study, a modeling chain framework to project future hydrological changes and the associated uncertainties in the Xijiang River basin, South China, was established. The framework consists of three emission scenarios (ESs), four climate models (CMs), four statistical downscaling (SD) methods, four hydrological modeling (HM) schemes, and four probability distributions (PDs) for extreme flow frequency analyses. Direct variance method was adopted to analyze the manner by which uncertainty sources such as ES, CM, SD, and HM affect the estimates of future evapotranspiration (ET) and streamflow, and to quantify the uncertainties of PDs in future flood and drought risk assessment. Results show that ES is one of the least important uncertainty sources in most situations. CM, in general, is the dominant uncertainty source for the projections of monthly ET and monthly streamflow during most of the annual cycle, daily streamflow below the 99.6% quantile level, and extreme low flow. SD is the most predominant uncertainty source in the projections of extreme high flow, and has a considerable percentage of uncertainty contribution in monthly streamflow projections in July-September. The effects of SD in other cases are negligible. HM is a non-ignorable uncertainty source that has the potential to produce much larger uncertainties for the projections of low flow and ET in warm and wet seasons than for the projections of high flow. PD contributes a larger percentage of uncertainty in extreme flood projections than it does in extreme low flow estimates. Despite the large uncertainties in hydrological projections, this work found that future extreme low flow would undergo a considerable reduction, and a noticeable increase in drought risk in the Xijiang River basin would be expected. Thus, the necessity of employing effective water-saving techniques and adaptive water resources management strategies for drought disaster mitigation should be addressed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29913597','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29913597"><span>Modelling impacts of climate change and socio-economic change on the Ganga, Brahmaputra, Meghna, Hooghly and Mahanadi river systems in India and Bangladesh.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Whitehead, Paul G; Jin, Li; Macadam, Ian; Janes, Tamara; Sarkar, Sananda; Rodda, Harvey J E; Sinha, Rajiv; Nicholls, Robert J</p> <p>2018-09-15</p> <p>The Ganga-Brahmaputra-Meghna (GBM) River System, the associated Hooghly River and the Mahanadi River System represent the largest river basins in the world serving a population of over 780 million. The rivers are of vital concern to India and Bangladesh as they provide fresh water for people, agriculture, industry, conservation and support the Delta System in the Bay of Bengal. Future changes in both climate and socio-economics have been investigated to assess whether these will alter river flows and water quality. Climate datasets downscaled from three different Global Climate Models have been used to drive a daily process based flow and water quality model. The results suggest that due to climate change the flows will increase in the monsoon period and also be enhanced in the dry season. However, once socio-economic changes are also considered, increased population, irrigation, water use and industrial development reduce water availability in drought conditions, threatening water supplies and posing a threat to river and coastal ecosystems. This study, as part of the DECCMA (Deltas, vulnerability and Climate Change: Migration and Adaptation) project, also addresses water quality issues, particularly nutrients (N and P) and their transport along the rivers and discharge into the Delta System. Climate will alter flows, increasing flood flows and changing pollution dilution factors in the rivers, as well as other key processes controlling water quality. Socio-economic change will affect water quality, as water diversion strategies, increased population and industrial development alter the water balance and enhance fluxes of nutrients from agriculture, urban centers and atmospheric deposition. Copyright © 2018 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.novapublishers.com/catalog/index.php','USGSPUBS'); return false;" href="https://www.novapublishers.com/catalog/index.php"><span>Contrasting fish assemblages in free-flowing and impounded tributaries to the Upper Delaware River: Implications for conserving biodiversity</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Baldigo, Barry P.; Delucia, Mari-Beth; Keller, Walter D.; Schuler, George E.; Apse, Colin D.; Moberg, Tara</p> <p>2015-01-01</p> <p>The Neversink River and the Beaver Kill in southeastern New York are major tributaries to the Delaware River, the longest undammed river east of the Mississippi. While the Beaver Kill is free flowing for its entire length, the Neversink River is subdivided by the Neversink Reservoir, which likely affects the diversity of local fish assemblages and health of aquatic ecosystems. The reservoir is an important part of the New York City waster-supply system that provides drinking water to more than 9 million people. Fish population and community data from recent quantitative surveys at comparable sites in both basins were assessed to characterize the differences between free-flowing and impounded rivers and the extent of reservoir effects to improve our capacity to define ecosystems responses that two modified flow-release programs (implemented in 2007 and 2011) should produce in the Neversink River. In general, the continuum of changes in fish assemblages which normally occur between headwaters and mouth was relatively uninterrupted in the Beaver Kill, but disrupted by the mid-basin impoundment in the Neversink River. Fish assemblages were also adversely affected at several acidified sites in the upper Neversink River, but not at most sites assessed herein. The reservoir clearly excluded diadromous species from the upper sub-basin, but it also substantially reduced community richness, diversity, and biomass at several mid-basin sites immediately downstream from the impoundment. There results will aid future attempts to determine if fish assemblages respond to more natural, yet highly regulated, flow regimes in the Neversink River. More important, knowledge gained from this study can help optimize use of valuable water resources while promoting species of special concern, such as American eel (Anguilla rostrata) and conserving biodiversity in Catskill Mountain streams.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.fcgov.com/naturalareas/eco-response.php','USGSPUBS'); return false;" href="http://www.fcgov.com/naturalareas/eco-response.php"><span>An ecological response model for the Cache la Poudre River through Fort Collins</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shanahan, Jennifer; Baker, Daniel; Bledsoe, Brian P.; Poff, LeRoy; Merritt, David M.; Bestgen, Kevin R.; Auble, Gregor T.; Kondratieff, Boris C.; Stokes, John; Lorie, Mark; Sanderson, John</p> <p>2014-01-01</p> <p>The ERM was designed to represent the multi-dimensional ecological character of the contemporary urban Poudre River. It provides a scientific foundation that can serve as a decision support tool and foster a more informed community discussion about the future of the river as it provides a better understanding of the likely response of the Poudre River ecosystem to environmental flow management and other stewardship activities. In particular, model results can assist managers in developing specific management actions to achieve desirable goals for key indicators of river health.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.6199P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.6199P"><span>Sediment transport patterns and climate change: the downstream Tuul River case study, Northern Mongolia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pietroń, Jan; Jarsjö, Jerker</p> <p>2014-05-01</p> <p>Ongoing changes in the Central Asian climate including increasing temperatures can influence the hydrological regimes of rivers and the waterborne transport of sediments. Changes in the latter, especially in combination with adverse human activities, may severely impact water quality and aquatic ecosystems. However, waterborne transport of sediments is a result of complex processes and varies considerably between, and even within, river systems. There is therefore a need to increase our general knowledge about sediment transport under changing climate conditions. The Tuul River, the case site of this study, is located in the upper part of the basin of the Selenga River that is the main tributary to Lake Baikal, a UNESCO World Heritage Site. Like many other rivers located in the steppes of Northern Mongolia, the Tuul River is characterized by a hydrological regime that is not disturbed by engineered structures such as reservoirs and dams. However, the water quality of the downstream Tuul River is increasingly affected by adverse human activities - including placer gold mining. The largest contribution to the annual river discharge occurs during the relatively warm period in May to August. Typically, there are numerous rainfall events during this period that cause considerable river flow peaks. Parallel work has furthermore shown that due to climate change, the daily variability of discharge and numbers of peak flow events in the Tuul River Basin has increased during the past 60 years. This trend is expected to continue. We here aim at increasing our understanding of future sediment transport patterns in the Tuul River, specifically considering the scenario that peak flow events may become more frequent due to climate change. We use a one-dimensional sediment transport model of the downstream reach of the river to simulate natural patterns of sediment transport for a recent hydrological year. In general, the results show that sediment transport varies considerably spatially and temporally. Peak flow events during the warm period contribute largely to the total annual transport of sediments and also to the erosion of stored bed material. These results suggest that if the number of peak flow events will increase further due to climate change, there will be a significant increase in the annual sediment load and consequently in the load of contaminants that are attached to the sediments, in particular downstream of mining sites. The present results are furthermore consistent with parallel studies on sediment transport and climate change showing that increased water discharges and frequencies of rainfall/flow events can lead to enhanced erosion processes. Furthermore, in addition to climate change effects, human activates can change sediment loads in rivers to even greater extent, as pointed out in several studies. Thus, several different challenges can be expected to face the management of Central Asian rivers such as Tuul and their ecosystems in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.1676A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.1676A"><span>Development of an inflow controlled environmental flow regime for a Norwegian river</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alfredsen, Knut; Harby, Atle; Linnansaari, Tommi; Ugedal, Ola</p> <p>2010-05-01</p> <p>For most regulated rivers in Norway the common environmental flow regime is static and shows very little variation over the year. Recent research indicate that flow regimes that follow the natural inflow variation can meet the ecological and social demands for water in a better way. The implementation of a variable environmental flow regime provides many challenges both related to defining flow for various species and user groups in the river, but also due to practical implementation, legislation and control. A inflow controlled flow regime is developed for a Norwegian river regulated for hydro power as a pilot study. The regime should meet ecological demands from Atlantic salmon and brown trout, recreational use of water and visual impression of the river. This should be achieved preferably without altering the energy production in the hydro power system. The flow regime is developed for wet, dry and normal discharge conditions based on unregulated inflow to the catchment. The development of the seasonal flow requirements for various targets identified is done using a modification of the Building Block Method. Several options are tested regarding the integration of the flow regime into the operational strategy of the hydropower plant, both using real time prognosis of inflow and combinations with historical data. An important topic in selecting the release strategy is how it meets current Norwegian legislation and how well future documentation and environmental control can be carried out. An evaluation protocol is also proposed for the flow regime to test if the ecological targets are met.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70021201','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70021201"><span>Modeling the effects of land use and climate change on riverine smallmouth bass</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Peterson, J.T.; Kwak, T.J.</p> <p>1999-01-01</p> <p>Anthropogenic changes in temperature and stream flow, associated with watershed land use and climate change, are critical influences on the distribution and abundance of riverine fishes. To project the effects of changing land use and climate, we modeled a smallmouth bass (Micropterus dolomieu) population in a midwestern USA, large river- floodplain ecosystem under historical (1915-1925), present (1977-1990), and future (2060, influenced by climate change) temperature and flow regimes. The age-structured model included parameters for temperature and river discharge during critical seasonal periods, fish population dynamics, and fishing harvest. Model relationships were developed from empirical field data collected over a 13-yr period. Sensitivity analyses indicated that discharge during the spawning/rearing period had a greater effect on adult density and fishing yield than did spawning/rearing temperature or winter discharge. Simulations for 100 years projected a 139% greater mean fish density under a historical flow regime (64.9 fish/ha) than that estimated for the present (27.1 fish/ha) with a sustainable fishing harvest under both flow regimes. Simulations under future climate-change-induced temperature and flow regimes with present land use projected a 69% decrease in mean fish density (8.5 fish/ha) from present and an unstable population that went extinct during 56% of the simulations. However, when simulated under a future climate-altered temperature and flow regime with historical land use, the population increased by 66% (45.0 fish/ha) from present and sustained a harvest. Our findings suggest that land-use changes may be a greater detriment to riverine fishes than projected climate change and that the combined effects of both factors may lead to local species extinction. However, the negative effects of increased temperature and precipitation associated with future global warming could be mitigated by river channel, floodplain, and watershed restoration.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H21L..07G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H21L..07G"><span>Variational Assimilation of Sparse and Uncertain Satellite Data For 1D Saint-Venant River Models</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garambois, P. A.; Brisset, P.; Monnier, J.; Roux, H.</p> <p>2016-12-01</p> <p>Profusion of satellites are providing increasingly accurate measurements of continental water cyle, and water bodies variations while in situ observability is declining. The future Surface Water and Ocean Topography (SWOT) mission will provide maps of river surface elevations widths and slopes with an almost global coverage and temporal revisits. This will offer the possibility to address a larger variety of inverse problems in surface hydrology. Data assimilation techniques, that are broadly used in several scientific fields, aim to optimally combine models, system observations and prior information. Variational assimilation consists in iterative minimization of a discrepency measure between model outputs and observations, here for retrieving boundary conditions and parameters of a 1D Saint Venant model. Nevertheless, inferring river discharge and hydraulic parameters thanks to the observation of river surface is not straightforward. This is particularly true in the case of sparse and uncertain observations of flow state variables since they are governed by nonlinear physical processes. This paper investigates the identifiability of hydraulic controls given sparse and uncertain satellite observations of a river. The identifiability of river discharge alone and with roughness is tested for several spatio temporal patterns of river observations, including SWOT like observations. A new 1D Shallow water model with variational data assimilation, within the DassFlow chain is presented as well as postprocessing and observation operator dedicated to the future SWOT and SWOT simulator data. In view to decrease inverse problem dimensionality discharge is represented in a reduced basis. Moreover we introduce an original and reduced parametrization of the flow resistance that can account for various flow regimes along with a cross section design dedicated to remote sensing. We show which discharge temporal frequencies can be identified w.r.t observation ones and at which accuracy. Eventually the important question of the discharge identifiability potential between observation times and depending on the spatio-temporal sampling is adressed with respect to the wave lengths of the hydrological signals.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24639551','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24639551"><span>Toward global mapping of river discharge using satellite images and at-many-stations hydraulic geometry.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gleason, Colin J; Smith, Laurence C</p> <p>2014-04-01</p> <p>Rivers provide critical water supply for many human societies and ecosystems, yet global knowledge of their flow rates is poor. We show that useful estimates of absolute river discharge (in cubic meters per second) may be derived solely from satellite images, with no ground-based or a priori information whatsoever. The approach works owing to discovery of a characteristic scaling law uniquely fundamental to natural rivers, here termed a river's at-many-stations hydraulic geometry. A first demonstration using Landsat Thematic Mapper images over three rivers in the United States, Canada, and China yields absolute discharges agreeing to within 20-30% of traditional in situ gauging station measurements and good tracking of flow changes over time. Within such accuracies, the door appears open for quantifying river resources globally with repeat imaging, both retroactively and henceforth into the future, with strong implications for water resource management, food security, ecosystem studies, flood forecasting, and geopolitics.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2007/5183/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2007/5183/"><span>Simulation of the Effects of Water Withdrawals, Wastewater Return Flows, and Land-Use Change on Streamflow in the Blackstone River Basin, Massachusetts and Rhode Island</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Barbaro, Jeffrey R.</p> <p>2007-01-01</p> <p>Streamflow in many parts of the Blackstone River Basin in south-central Massachusetts and northern Rhode Island is altered by water-supply withdrawals, wastewater-return flows, and land-use change associated with a growing population. Simulations from a previously developed and calibrated Hydrological Simulation Program?FORTRAN (HSPF) precipitation-runoff model for the basin were used to evaluate the effects of water withdrawals, wastewater-return flows, and land-use change on streamflow. Most of the simulations were done for recent (1996?2001) conditions and potential buildout conditions in the future when all available land is developed to provide a long-range assessment of the effects of possible future human activities on water resources in the basin. The effects of land-use change were evaluated by comparing the results of long-term (1960?2004) simulations with (1) undeveloped land use, (2) 1995?1999 land use, and (3) potential buildout land use at selected sites across the basin. Flow-duration curves for these land-use scenarios were similar, indicating that land-use change, as represented in the HSPF model, had little effect on flow in the major tributary streams and rivers in the basin. However, land-use change?particularly increased effective impervious area?could potentially have greater effects on the hydrology, water quality, and aquatic habitat of the smaller streams in the basin. The effects of water withdrawals and wastewater-return flows were evaluated by comparing the results of long-term simulations with (1) no withdrawals and return flows, (2) actual (measured) 1996?2001 withdrawals and wastewater-return flows, and (3) potential withdrawals and wastewater-return flows at buildout. Overall, the results indicated that water use had a much larger effect on streamflow than did land use, and that the location and magnitude of wastewater-return flows were important for lessening the effects of withdrawals on streamflow in the Blackstone River Basin. Ratios of long-term (1960?2004) simulated flows with 1996?2001 water use (representing the net effect of withdrawals and wastewater-return flows) to long-term simulated flows with no water use indicated that, for many reaches, 1996?2001 water use did not deplete flows at the 90-percent flow duration substantially compared to flows unaffected by water use. Flows generally were more severely depleted in the reaches that include surface-water supplies for the larger cities in the basin (Kettle and Tatnuck Brooks, Worcester, Mass. water supply; Quinsigamond River, Shrewsbury, Mass. water supply; Crookfall Brook, Woonsocket, R.I. water supply; and Abbott Run, Pawtucket, R.I. water supply). These reaches did not have substantial wastewater-return flows that could offset the effects of the withdrawals. In contrast, wastewater-return flows from the Upper Blackstone Wastewater Treatment Facility in Millbury, Mass. increased flows at the 90-percent flow duration in the main stem of the Blackstone River compared to no-water-use conditions. Under the assumptions used to develop the buildout scenario, nearly all of the new water withdrawals were returned to the Blackstone River Basin at municipal wastewater-treatment plants or on-site septic systems. Consequently, buildout generally had small effects on simulated low flows in the Blackstone River and most of the major tributary streams compared to flows with 1996?2001 water use. To evaluate the effects of water use on flows in the rivers and major tributary streams in the Rhode Island part of the basin in greater detail, the magnitudes of water withdrawals and wastewater-return flows in relation to simulated streamflow were calculated as unique ratios for individual HSPF subbasins, total contributing areas to HSPF subbasins, and total contributing areas to the major tributary streams. For recent conditions (1996?2001 withdrawals and 1995?1999 land use), ratios of average summer (June through September) withdrawals to the l</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC54B..01Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC54B..01Y"><span>Development and Evaluation of an Integrated Hydrological Modeling Framework for Monitoring and Understanding Floods and Droughts</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Z. L.; Wu, W. Y.; Lin, P.; Maidment, D. R.</p> <p>2017-12-01</p> <p>Extreme water events such as catastrophic floods and severe droughts have increased in recent decades. Mitigating the risk to lives, food security, infrastructure, energy supplies, as well as numerous other industries posed by these extreme events requires informed decision-making and planning based on sound science. We are developing a global water modeling capability by building models that will provide total operational water predictions (evapotranspiration, soil moisture, groundwater, channel flow, inundation, snow) at unprecedented spatial resolutions and updated frequencies. Toward this goal, this talk presents an integrated global hydrological modeling framework that takes advantage of gridded meteorological forcing, land surface modeling, channeled flow modeling, ground observations, and satellite remote sensing. Launched in August 2016, the National Water Model successfully incorporates weather forecasts to predict river flows for more than 2.7 million rivers across the continental United States, which transfers a "synoptic weather map" to a "synoptic river flow map" operationally. In this study, we apply a similar framework to a high-resolution global river network database, which is developed from a hierarchical Dominant River Tracing (DRT) algorithm, and runoff output from the Global Land Data Assimilation System (GLDAS) to a vector-based river routing model (The Routing Application for Parallel Computation of Discharge, RAPID) to produce river flows from 2001 to 2016 using Message Passing Interface (MPI) on Texas Advanced Computer Center's Stampede system. In this simulation, global river discharges for more than 177,000 rivers are computed every 30 minutes. The modeling framework's performance is evaluated with various observations including river flows at more than 400 gauge stations globally. Overall, the model exhibits a reasonably good performance in simulating the averaged patterns of terrestrial water storage, evapotranspiration and runoff. The system is appropriate for monitoring and studying floods and droughts. Directions for future research will be outlined and discussed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H23E1734L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H23E1734L"><span>Residence Times in Central Valley Aquifers Recharged by Dammed Rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Loustale, M.; Paukert Vankeuren, A. N.; Visser, A.</p> <p>2017-12-01</p> <p>Groundwater is a vital resource for California, providing between 30-60% of the state's water supply. Recent emphasis on groundwater sustainability has induced a push to characterize recharge rates and residence times for high priority aquifers, including most aquifers in California's Central Valley. Flows in almost all rivers from the western Sierra to the Central Valley are controlled by dams, altering natural flow patterns and recharge to local aquifers. In eastern Sacramento, unconfined and confined shallow aquifers (depth <300 feet) are recharged by a losing reach of the Lower American River, despite the presence of levees with slurry cut-off walls.1 Flow in the Lower American River is controlled through the operation of the Folsom and Nimbus Dams, with a minimum flow of 500 cfs. Water table elevation in wells in close proximity to the river are compared to river stage to determine the effect of river stage on groundwater recharge rates. Additionally, Tritium-3Helium dates and stable isotopes (∂18O and ∂2H) have been measured in monitoring wells 200- 2400 ft lateral distance from the river, and depths of 25 -225 feet BGS. Variation in groundwater age in the vertical and horizontal directions are used to determine groundwater flow path and velocity. These data are then used to calculate residence time of groundwater in the unconfined and confined aquifer systems for the Central Valley in eastern Sacramento. Applying groundwater age tracers can benefit future compliance metrics of the California Sustainable Groundwater Resources Act (SGMA), by quantifying river seepage rates and impacts of groundwater management on surface water resources. 1Moran et al., UCRL-TR-203258, 2004.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H34G..02Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H34G..02Y"><span>Assessment of Environmental Flows under Human Intervention and Climate Change Conditions in a Mediterranean Watershed</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yilmaz, M. T.; Alp, E.; Aras, M.; Özaltın, A. M.; Sarıcan, Y.; Afsar, M.; Bulut, B.; Ersoy, E. N.; Karasu, İ. G.; Onen, A.</p> <p>2017-12-01</p> <p>Allocation of the river flow for ecosystems is very critical for sustainable management of ecosystems containing aquatic habitats in need of more water than other environments. Availability and allocation of water over such locations becomes more stressed as a result of the influence of human interventions (e.g., increased water use for irrigation) and the expected change in climate. This study investigates the current and future (until 2100) low-flow requirements over 10 subcatchments in a Mediterranean Watershed, in Turkey, using Tennant and hydrological low-flow methods. The future river flows are estimated using HBV model forced by climate projections obtained by HADGEM2, MPI-ESM-MR, and CNRM-CM5.1 models coupled with RegCM4.3 under RCP 4.5 and RCP 8.5 emission scenarios. Critical flows (i.e., Q10, Q25, Q50) are calculated using the best fit to commonly used distributions for the river flow data, while the decision between the selection of Q10, Q25, Q50 critical levels are made depending on the level of human interference made over the catchment. Total three low-flow requirement estimations are obtained over each subcatchment using the Tennant (two estimates for the low and high flow seasons for environmentally good conditions) and the hydrological low-flow methods. The highest estimate among these three methods is selected as the low-flow requirement of the subcatchment. The river flows over these 10 subcatchments range between 197hm3 and 1534hm3 while the drainage areas changing between 936 and 4505 km2. The final low-flow estimation (i.e., the highest among the three estimate) for the current conditions range between 94 hm3 and 715 hm3. The low-flow projection values between 2075 and 2099 are on average 39% lower than the 2016 values, while the steepest decline is expected between 2050 and 2074. The low flow and high flow season Tennant estimates dropped 22-25% while the hydrological method low-flow estimates dropped 32% from 2016 to 2075-2099 average, where Tennant estimates are sensitive to the precipitation projections while hydrological flow estimates are sensitive to the degree that the subcatchment flows are regulated/intervened. On the other hand, the combined low-flow estimate, the highest of three methods, dropped around 39%, reflecting combined impact of human intervention and climate change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22543580','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22543580"><span>Putting the "ecology" into environmental flows: ecological dynamics and demographic modelling.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shenton, Will; Bond, Nicholas R; Yen, Jian D L; Mac Nally, Ralph</p> <p>2012-07-01</p> <p>There have been significant diversions of water from rivers and streams around the world; natural flow regimes have been perturbed by dams, barriers and excessive extractions. Many aspects of the ecological 'health' of riverine systems have declined due to changes in water flows, which has stimulated the development of thinking about the maintenance and restoration of these systems, which we refer to as environmental flow methodologies (EFMs). Most existing EFMs cannot deliver information on the population viability of species because they: (1) use habitat suitability as a proxy for population status; (2) use historical time series (usually of short duration) to forecast future conditions and flow sequences; (3) cannot, or do not, handle extreme flow events associated with climate variability; and (4) assume process stationarity for flow sequences, which means the past sequences are treated as good indicators of the future. These assumptions undermine the capacity of EFMs to properly represent risks associated with different flow management options; assumption (4) is untenable given most climate-change predictions. We discuss these concerns and advocate the use of demographic modelling as a more appropriate tool for linking population dynamics to flow regime change. A 'meta-species' approach to demographic modelling is discussed as a useful step from habitat based models towards modelling strategies grounded in ecological theory when limited data are available on flow-demographic relationships. Data requirements of demographic models will undoubtedly expose gaps in existing knowledge, but, in so doing, will strengthen future efforts to link changes in river flows with their ecological consequences.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EnMan..50....1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EnMan..50....1S"><span>Putting the "Ecology" into Environmental Flows: Ecological Dynamics and Demographic Modelling</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shenton, Will; Bond, Nicholas R.; Yen, Jian D. L.; Mac Nally, Ralph</p> <p>2012-07-01</p> <p>There have been significant diversions of water from rivers and streams around the world; natural flow regimes have been perturbed by dams, barriers and excessive extractions. Many aspects of the ecological `health' of riverine systems have declined due to changes in water flows, which has stimulated the development of thinking about the maintenance and restoration of these systems, which we refer to as environmental flow methodologies (EFMs). Most existing EFMs cannot deliver information on the population viability of species because they: (1) use habitat suitability as a proxy for population status; (2) use historical time series (usually of short duration) to forecast future conditions and flow sequences; (3) cannot, or do not, handle extreme flow events associated with climate variability; and (4) assume process stationarity for flow sequences, which means the past sequences are treated as good indicators of the future. These assumptions undermine the capacity of EFMs to properly represent risks associated with different flow management options; assumption (4) is untenable given most climate-change predictions. We discuss these concerns and advocate the use of demographic modelling as a more appropriate tool for linking population dynamics to flow regime change. A `meta-species' approach to demographic modelling is discussed as a useful step from habitat based models towards modelling strategies grounded in ecological theory when limited data are available on flow-demographic relationships. Data requirements of demographic models will undoubtedly expose gaps in existing knowledge, but, in so doing, will strengthen future efforts to link changes in river flows with their ecological consequences.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2010/1086/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2010/1086/"><span>Channel Maintenance and Flushing Flows for the Klamath River Below Iron Gate Dam, California</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Holmquist-Johnson, Cristopher L.; Milhous, Robert T.</p> <p>2010-01-01</p> <p>The Klamath River is a major river in northern California and southern Oregon. Iron Gate Dam divides the river into the two subunits where there is a significant change in utilization of the river. Downstream of Iron Gate Dam, the river is very important for the propagation of salmon. To address concerns relating to substrate conditions in the mainstem Klamath River below Iron Gate Dam, the Arcata, California, office of the U.S. Fish and Wildlife Service contracted with the U.S. Geological Survey (USGS) to determine flushing flows required to improve and maintain quality spawning and rearing habitats for salmon, and to reduce the abundance of preferred habitats of the polychaete worm suspected of being the intermediate host for Ceratomyxa shasta, a species of bacteria that infects fish. Historically, the river has had the capacity to move sediment just below Iron Gate Reservoir, but there have been periods when the capacity was very low. The results indicate that if the future is more like the pre-1961 period (low transport capacity) than the more recent period, there will be significant sediment issues in the Klamath River below Iron Gate Dam. It seems that during normal or wet years, winter months, and periods of high flow, sediments are flushed either downstream or deposited on higher surfaces. The recent drought conditions during 2000-2005 probably resulted in extensive fine-grained sedimentation along the river, which in turn may have caused increased establishment of aquatic vegetation and increased concentrations of C. shasta. It appears that releases from Iron Gate Dam as far downstream as Seiad Valley are important in maintaining flow conditions to flush the fines and clean the gravels in the river during summer months, or during drought years. Sediment transport studies indicate that supplemental flows during dry or drought conditions may provide some flushing flows in reaches downstream of the dam. For purposes of flushing fine sediments during drought years or dry summer months, flows in the range of 2,500-5,000 cubic feet per second during a period of days may be necessary. Providing these types of flows in a manner similar to a storm pulse would provide the best opportunity to flush the fines and clean some of the gravels given the upper ranges of flows are achieved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ERL....10a5001G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ERL....10a5001G"><span>An index-based framework for assessing patterns and trends in river fragmentation and flow regulation by global dams at multiple scales</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grill, Günther; Lehner, Bernhard; Lumsdon, Alexander E.; MacDonald, Graham K.; Zarfl, Christiane; Reidy Liermann, Catherine</p> <p>2015-01-01</p> <p>The global number of dam constructions has increased dramatically over the past six decades and is forecast to continue to rise, particularly in less industrialized regions. Identifying development pathways that can deliver the benefits of new infrastructure while also maintaining healthy and productive river systems is a great challenge that requires understanding the multifaceted impacts of dams at a range of scales. New approaches and advanced methodologies are needed to improve predictions of how future dam construction will affect biodiversity, ecosystem functioning, and fluvial geomorphology worldwide, helping to frame a global strategy to achieve sustainable dam development. Here, we respond to this need by applying a graph-based river routing model to simultaneously assess flow regulation and fragmentation by dams at multiple scales using data at high spatial resolution. We calculated the cumulative impact of a set of 6374 large existing dams and 3377 planned or proposed dams on river connectivity and river flow at basin and subbasin scales by fusing two novel indicators to create a holistic dam impact matrix for the period 1930-2030. Static network descriptors such as basin area or channel length are of limited use in hierarchically nested and dynamic river systems, so we developed the river fragmentation index and the river regulation index, which are based on river volume. These indicators are less sensitive to the effects of network configuration, offering increased comparability among studies with disparate hydrographies as well as across scales. Our results indicate that, on a global basis, 48% of river volume is moderately to severely impacted by either flow regulation, fragmentation, or both. Assuming completion of all dams planned and under construction in our future scenario, this number would nearly double to 93%, largely due to major dam construction in the Amazon Basin. We provide evidence for the importance of considering small to medium sized dams and for the need to include waterfalls to establish a baseline of natural fragmentation. Our versatile framework can serve as a component of river fragmentation and connectivity assessments; as a standardized, easily replicable monitoring framework at global and basin scales; and as part of regional dam planning and management strategies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3709493','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3709493"><span>Human deforestation outweighs future climate change impacts of sedimentation on coral reefs</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Maina, Joseph; de Moel, Hans; Zinke, Jens; Madin, Joshua; McClanahan, Tim; Vermaat, Jan E.</p> <p>2013-01-01</p> <p>Near-shore coral reef systems are experiencing increased sediment supply due to conversion of forests to other land uses. Counteracting increased sediment loads requires an understanding of the relationship between forest cover and sediment supply, and how this relationship might change in the future. Here we study this relationship by simulating river flow and sediment supply in four watersheds that are adjacent to Madagascar’s major coral reef ecosystems for a range of future climate change projections and land-use change scenarios. We show that by 2090, all four watersheds are predicted to experience temperature increases and/or precipitation declines that, when combined, result in decreases in river flow and sediment load. However, these climate change-driven declines are outweighed by the impact of deforestation. Consequently, our analyses suggest that regional land-use management is more important than mediating climate change for influencing sedimentation of Malagasy coral reefs. PMID:23736941</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23736941','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23736941"><span>Human deforestation outweighs future climate change impacts of sedimentation on coral reefs.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maina, Joseph; de Moel, Hans; Zinke, Jens; Madin, Joshua; McClanahan, Tim; Vermaat, Jan E</p> <p>2013-01-01</p> <p>Near-shore coral reef systems are experiencing increased sediment supply due to conversion of forests to other land uses. Counteracting increased sediment loads requires an understanding of the relationship between forest cover and sediment supply, and how this relationship might change in the future. Here we study this relationship by simulating river flow and sediment supply in four watersheds that are adjacent to Madagascar's major coral reef ecosystems for a range of future climate change projections and land-use change scenarios. We show that by 2090, all four watersheds are predicted to experience temperature increases and/or precipitation declines that, when combined, result in decreases in river flow and sediment load. However, these climate change-driven declines are outweighed by the impact of deforestation. Consequently, our analyses suggest that regional land-use management is more important than mediating climate change for influencing sedimentation of Malagasy coral reefs.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JHyd..342..336F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JHyd..342..336F"><span>Modeling changes in summer temperature of the Fraser River during the next century</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ferrari, Michael R.; Miller, James R.; Russell, Gary L.</p> <p>2007-09-01</p> <p>SummaryThe Fraser River basin in British Columbia has significant environmental, economic and cultural importance. Healthy river conditions through sufficient flows and optimal temperatures are of paramount importance for the survival of Pacific salmon, which migrate upriver toward the headwaters to spawn near the end of their lives. Trends have been detected which indicate that the annual flow and summer temperature have been increasing since the middle of the last century. In this study we examine the observed trend in summer temperature of the Fraser River and compare it with temperatures calculated as part of a global climate model (GCM) simulation in which atmospheric greenhouse gases are increasing. We then use the GCM to consider how these trends might continue through the present century. Both the observations and model indicate that during the last half of the 20th century, the summer temperature near the river mouth has been increasing at a rate of approximately 0.12 °C per decade in August. In this study we use an online method in which river temperatures are calculated directly as part of a GCM simulation and project how summer temperature near the mouth of the Fraser River might change by the end of the present century. The results indicate that between 2000 and 2100 river temperatures will increase in all summer months with a maximum increase of 0.14 °C per decade in August. This result is consistent with an offline modeling study by [Morrison, J., Quick, M.C., Goreman, M.G.G. 2002. Climate change in the Fraser River watershed: flow and temperature projections. Journal of Hydrology, 263, 230-244] in which they used output from two GCMS to drive a hydrologic model and predict future changes in river temperature and supports their contention that the timing and magnitude of the increase could be crucial for salmon migration. Future work can extend this analysis to other river systems in an effort to project the potential effects of climate change on the behavior of the world's large river basins, as well as identify the potential biological effects that may accompany these changes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.9347P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.9347P"><span>Future efficiency of run of the river hydropower schemes based on climate change scenarios: case study in UK catchments</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pasten Zapata, Ernesto; Moggridge, Helen; Jones, Julie; Widmann, Martin</p> <p>2017-04-01</p> <p>Run-of-the-River (ROR) hydropower schemes are expected to be importantly affected by climate change as they rely in the availability of river flow to generate energy. As temperature and precipitation are expected to vary in the future, the hydrological cycle will also undergo changes. Therefore, climate models based on complex physical atmospheric interactions have been developed to simulate future climate scenarios considering the atmosphere's greenhouse gas concentrations. These scenarios are classified according to the Representative Concentration Pathways (RCP) that are generated according to the concentration of greenhouse gases. This study evaluates possible scenarios for selected ROR hydropower schemes within the UK, considering three different RCPs: 2.6, 4.5 and 8.5 W/m2 for 2100 relative to pre-industrial values. The study sites cover different climate, land cover, topographic and hydropower scheme characteristics representative of the UK's heterogeneity. Precipitation and temperature outputs from state-of-the-art Regional Climate Models (RCMs) from the Euro-CORDEX project are used as input for a HEC-HMS hydrological model to simulate the future river flow available. Both uncorrected and bias-corrected RCM simulations are analyzed. The results of this project provide an insight of the possible effects of climate change towards the generation of power from the ROR hydropower schemes according to the different RCP scenarios and contrasts the results obtained from uncorrected and bias-corrected RCMs. This analysis can aid on the adaptation to climate change as well as the planning of future ROR schemes in the region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5747487','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5747487"><span>Future changes in hydro-climatic extremes in the Upper Indus, Ganges, and Brahmaputra River basins</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lutz, Arthur F.; Nepal, Santosh; Khanal, Sonu; Pradhananga, Saurav; Shrestha, Arun B.; Immerzeel, Walter W.</p> <p>2017-01-01</p> <p>Future hydrological extremes, such as floods and droughts, may pose serious threats for the livelihoods in the upstream domains of the Indus, Ganges, Brahmaputra. For this reason, the impacts of climate change on future hydrological extremes is investigated in these river basins. We use a fully-distributed cryospheric-hydrological model to simulate current and future hydrological fluxes and force the model with an ensemble of 8 downscaled General Circulation Models (GCMs) that are selected from the RCP4.5 and RCP8.5 scenarios. The model is calibrated on observed daily discharge and geodetic mass balances. The climate forcing and the outputs of the hydrological model are used to evaluate future changes in climatic extremes, and hydrological extremes by focusing on high and low flows. The outcomes show an increase in the magnitude of climatic means and extremes towards the end of the 21st century where climatic extremes tend to increase stronger than climatic means. Future mean discharge and high flow conditions will very likely increase. These increases might mainly be the result of increasing precipitation extremes. To some extent temperature extremes might also contribute to increasing discharge extremes, although this is highly dependent on magnitude of change in temperature extremes. Low flow conditions may occur less frequently, although the uncertainties in low flow projections can be high. The results of this study may contribute to improved understanding on the implications of climate change for the occurrence of future hydrological extremes in the Hindu Kush–Himalayan region. PMID:29287098</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.6170D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.6170D"><span>Potential impact of lava flows on regional water supplies: case study of central Oregon Cascades volcanism and the Willamette Valley, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deligne, Natalia; Cashman, Katharine; Grant, Gordon; Jefferson, Anne</p> <p>2013-04-01</p> <p>Lava flows are often considered to be natural hazards with localized bimodal impact - they completely destroy everything in their path, but apart from the occasional forest fire, cause little or no damage outside their immediate footprint. However, in certain settings, lava flows can have surprising far reaching impacts with the potential to cause serious problems in distant urban areas. Here we present results from a study of the interaction between lava flows and surface water in the central Oregon Cascades, USA, where we find that lava flows in the High Cascades have the potential to cause considerable water shortages in Eugene, Oregon (Oregon's second largest metropolitan area) and the greater Willamette Valley (home to ~70% of Oregon's population). The High Cascades host a groundwater dominated hydrological regime with water residence times on the order of years. Due to the steady output of groundwater, rivers sourced in the High Cascades are a critical water resource for Oregon, particularly in August and September when it has not rained for several months. One such river, the McKenzie River, is the sole source of drinking water for Eugene, Oregon, and prior to the installation of dams in the 1960s accounted for ~40% of late summer river flow in the Willamette River in Portland, 445 river km downstream of the source of the McKenzie River. The McKenzie River has been dammed at least twice by lava flows during the Holocene; depending the time of year that these eruptions occurred, we project that available water would have decreased by 20% in present-day Eugene, Oregon, for days to weeks at a time. Given the importance of the McKenzie River and its location on the margin of an active volcanic area, we expect that future volcanic eruptions could likewise impact water supplies in Eugene and the greater Willamette Valley. As such, the urban center of Eugene, Oregon, and also the greater Willamette Valley, is vulnerable to the most benign of volcanic hazards, lava flows, located over 100 km away.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=191002&keyword=luis&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=191002&keyword=luis&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>The Response of Fish Habitat to Environmental Flows in the Albemarle-Pamlico Watershed</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The provision of habitat for fish is an important service provided by rivers. Future land development and climate change will likely alter several aspects of habitat, including flow. We have used hierarchical models to predict the presence of 25 fish species within the Albemarle-...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70027826','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70027826"><span>Effects of stream flow intermittency on riparian vegetation of a semiarid region river (San Pedro River, Arizona)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stromberg, J.C.; Bagstad, K.J.; Leenhouts, J.M.; Lite, S.J.; Makings, E.</p> <p>2005-01-01</p> <p>The San Pedro River in the southwestern United States retains a natural flood regime and has several reaches with perennial stream flow and shallow ground water. However, much of the river flows intermittently. Urbanization-linked declines in regional ground-water levels have raised concerns over the future status of the riverine ecosystem in some parts of the river, while restoration-linked decreases in agricultural ground-water pumping are expected to increase stream flows in other parts. This study describes the response of the streamside herbaceous vegetation to changes in stream flow permanence. During the early summer dry season, streamside herbaceous cover and species richness declined continuously across spatial gradients of flow permanence, and composition shifted from hydric to mesic species at sites with more intermittent flow. Hydrologic threshold values were evident for one plant functional group: Schoenoplectus acutus, Juncus torreyi, and other hydric riparian plants declined sharply in cover with loss of perennial stream flow. In contrast, cover of mesic riparian perennials (including Cynodon dactylon, an introduced species) increased at sites with intermittent flow. Patterns of hydric and mesic riparian annuals varied by season: in the early summer dry season their cover declined continuously as flow became more intermittent, while in the late summer wet season their cover increased as the flow became more intermittent. Periodic drought at the intermittent sites may increase opportunities for establishment of these annuals during the monsoonal flood season. During the late summer flood season, stream flow was present at most sites, and fewer vegetation traits were correlated with flow permanence; cover and richness were correlated with other environmental factors including site elevation and substrate nitrate level and particle size. Although perennial-flow and intermittent-flow sites support different streamside plant communities, all of the plant functional groups are abundant at perennial-flow sites when viewing the ecosystem at broader spatial and temporal scales: mesic riparian perennials are common in the floodplain zone adjacent to the river channel and late-summer hydric and mesic annuals are periodically abundant after large floods. Copyright ?? 2005 John Wiley & Sons, Ltd.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMEP54B..01C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMEP54B..01C"><span>Connectivity of Secondary Channels in the Floodplain of a Low-Gradient Midwestern U.S. Agricultural River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Czuba, J. A.; David, S. R.; Edmonds, D. A.</p> <p>2016-12-01</p> <p>Floodplains of low-gradient Midwestern U.S. agricultural rivers are commonly dissected by a network of secondary channels that convey flow only during flood events. These networks of secondary channels have only recently been revealed by high resolution digital elevation models. Secondary channels, as referred to here, span multiple meander wavelengths and appear fundamentally different from chute channels. While secondary channels have been described to some extent in other river systems, our focus here is on those found in Indiana, which are revealed by state-wide LiDAR data acquired in 2011. In this work, we quantify how the network connectivity of the secondary channels in the floodplain develops as a function of flow stage. Secondary channels begin conveying water at stages just below bankfull, become an interconnected web of flow pathways above bankfull stage, and are completely inundated at higher stages. We construct a two-dimensional numerical model of the river/floodplain system from LiDAR data and from main-channel river bathymetry in order to obtain the extent of floodplain inundation at various flows. The inundated area within the secondary channels is then converted into a river/floodplain flow-channel network and quantified using various network metrics. Future work will explore the morphodynamics of this river/floodplain system extended to 100-1,000 year timescales. The goal is to develop a simple model to test hypotheses about how these floodplain channels evolve. Relevant research questions include: do secondary channels serve as preferential avulsion pathways? Or could secondary channels evolve to create a multi-channeled anabranching system? Furthermore, under what hydrologic and sedimentologic conditions would a river/floodplain system evolve to one state or another?</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.water.usgs.gov/sir20045024','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/sir20045024"><span>Methods to Identify Changes in Background Water-Quality Conditions Using Dissolved-Solids Concentrations and Loads as Indicators, Arkansas River and Fountain Creek, in the Vicinity of Pueblo, Colorado</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ortiz, Roderick F.</p> <p>2004-01-01</p> <p>Effective management of existing water-storage capacity in the Arkansas River Basin is anticipated to help satisfy the need for water in southeastern Colorado. A strategy to meet these needs has been developed, but implementation could affect the water quality of the Arkansas River and Fountain Creek in the vicinity of Pueblo, Colorado. Because no known methods are available to determine what effects future changes in operations will have on water quality, the U.S. Geological Survey, in cooperation with the Southeastern Colorado Water Activity Enterprise, began a study in 2002 to develop methods that could identify if future water-quality conditions have changed significantly from background (preexisting) water-quality conditions. A method was developed to identify when significant departures from background (preexisting) water-quality conditions occur in the lower Arkansas River and Fountain Creek in the vicinity of Pueblo, Colorado. Additionally, the methods described in this report provide information that can be used by various water-resource agencies for an internet-based decision-support tool. Estimated dissolved-solids concentrations at five sites in the study area were evaluated to designate historical background conditions and to calculate tolerance limits used to identify statistical departures from background conditions. This method provided a tool that could be applied with defined statistical probabilities associated with specific tolerance limits. Drought data from 2002 were used to test the method. Dissolved-solids concentrations exceeded the tolerance limits at all four sites on the Arkansas River at some point during 2002. The number of exceedances was particularly evident when streamflow from Pueblo Reservoir was reduced, and return flows and ground-water influences to the river were more prevalent. No exceedances were observed at the site on Fountain Creek. These comparisons illustrated the need to adjust the concentration data to account for varying streamflow. As such, similar comparisons between flow-adjusted data were done. At the site Arkansas River near Avondale, nearly all the 2002 flow-adjusted concentration data were less than the flow-adjusted tolerance limit which illustrated the effects of using flow-adjusted concentrations. Numerous exceedances of the flow-adjusted tolerance limits, however, were observed at the sites Arkansas River above Pueblo and Arkansas River at Pueblo. These results indicated that the method was able to identify a change in the ratio of source waters under drought conditions. Additionally, tolerance limits were calculated for daily dissolved-solids load and evaluated in a similar manner. Several other mass-load approaches were presented to help identify long-term changes in water quality. These included comparisons of cumulative mass load at selected sites and comparisons of mass load contributed at the Arkansas River near Avondale site by measured and unmeasured sources.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://digitalmedia.fws.gov/cdm/singleitem/collection/document/id/2152/rec/19','USGSPUBS'); return false;" href="https://digitalmedia.fws.gov/cdm/singleitem/collection/document/id/2152/rec/19"><span>Establishing links between streamflow and ecological integrity in the Sudbury River (Northeastern U.S.)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Roy, Allison; Jane, Stephen F.; Hazelton, Peter D.; Richards, Todd A.; Finn, John T.; Randhir, Timothy O.</p> <p>2016-01-01</p> <p>With increased pressure from a growing human population, managers are challenged to understand how novel disturbances (e.g., climate change, increased water withdrawals, urbanization) may affect natural resources. The Sudbury River is a National Wild and Scenic River located in suburban Boston, Massachusetts (Northeastern US) with myriad impairments (e.g., mainstem impoundments, withdrawals, and urbanization) that is under increasing pressure from hydrologic alteration. We sampled fish, mussel, and macroinvertebrate assemblages in the Sudbury River and used species traits to investigate potential effects of past and future flow alteration on biota. Analysis of 33 years of stream gage data indicates continued hydrologic alteration of the Sudbury River, likely related to increased urbanization and water withdrawals over that time. These changes include a roughly 200% increase in rise rates of flows, an approximate 65% decrease in 1-day minimum flows, and a trend towards increasing high flow pulse counts. Biotic sampling in summer of 2014 demonstrated that the Sudbury River is now dominated by generalist species. Of five mussel species sampled, all are generalists in their habitat requirements. Though one mussel species of special concern was sampled, the most abundant species collected were the widespread Eastern elliptio (58%) and Eastern lampmussel (40%). We used the target fish community (TFC) model to assess the degree to which the fish assemblage deviated from that expected for a river with similar zoogeographic and physical features. Overall, the current community has a 22.7% similarity to the TFC. Of the four fluvial specialist species present in the TFC, only fallfish was sampled in our study. While the TFC showed that the historical assemblage was likely dominated by fluvial specialist and fluvial dependent species, the current assemblage is overwhelmingly dominated by macrohabitat generalists (90.6% of fishes sampled). These results are consistent with other studies that show shifts in assemblages from fluvial specialists to habitat generalists with hydrologic alteration. If the current trends continue, it is likely that biotic assemblages will experience increasing pressure from hydrologic alteration. While hydrologic alteration is likely impacting biotic assemblages in the Sudbury River, other factors such as high temperatures, low dissolved oxygen, high nutrients, low availability of high-quality habitat, and poor habitat connectivity may also be negatively impacting biotic assemblages. Comparisons to other rivers and a complete longitudinal habitat survey could help to identify availability of unique habitats and representativeness of this study. While this study suggests impacts of flow on biota, future studies with quantitative, habitat-specific sampling during different flow levels could help to directly identify links between hydrologic alteration and biotic impairment in the Sudbury River.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3977244','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3977244"><span>Toward global mapping of river discharge using satellite images and at-many-stations hydraulic geometry</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gleason, Colin J.; Smith, Laurence C.</p> <p>2014-01-01</p> <p>Rivers provide critical water supply for many human societies and ecosystems, yet global knowledge of their flow rates is poor. We show that useful estimates of absolute river discharge (in cubic meters per second) may be derived solely from satellite images, with no ground-based or a priori information whatsoever. The approach works owing to discovery of a characteristic scaling law uniquely fundamental to natural rivers, here termed a river’s at-many-stations hydraulic geometry. A first demonstration using Landsat Thematic Mapper images over three rivers in the United States, Canada, and China yields absolute discharges agreeing to within 20–30% of traditional in situ gauging station measurements and good tracking of flow changes over time. Within such accuracies, the door appears open for quantifying river resources globally with repeat imaging, both retroactively and henceforth into the future, with strong implications for water resource management, food security, ecosystem studies, flood forecasting, and geopolitics. PMID:24639551</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70187050','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70187050"><span>Mapping the response of riparian vegetation to possible flow reductions in the Snake River, Idaho</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Johnson, W. Carter; Dixon, Mark D.; Simons, Robert W.; Jenson, Susan; Larson, Kevin</p> <p>1995-01-01</p> <p>This study was initiated to determine the general effects of potential flow reductions in the middle Snake River (Swan Falls Dam downstream to the Idaho-Oregon border) on its riparian vegetation. Considerable water from the river is currently used to irrigate the adjacent Snake River Plain, and increased demand for water in the future is likely. The problem was subdivided into several research components including: field investigation of the existing riparian vegetation and river environment, hydrological modeling to calculate the effects of one flow scenario on hydrological regime, and integration of vegetation and hydrological modeling results with a Geographic Information System (GIs) to map the riverbed, island, and bank conditions under the scenario flow. Field work was conducted in summer 1990. Riparian vegetation along 40 U.S. Geological Survey cross-sections was sampled at approximately 1.25 mile intervals within the 50 mile long study area. Cross-section and flow data were provided by the U.S. Geological. Survey. GIs mapping of land/water cover using ARC/INFO was based on 1987 aerial photographs. Riverbed contour maps were produced by linking cross-section data, topographic contouring software (anudem), and GIs. The maps were used to spatially display shallow areas in the channel likely to become vegetated under reduced flow conditions. The scenario would reduce flow by approximately 20% (160 MAF) and lower the river an average of 0.5 ft. The scenario flow could cause a drop in the elevation of the riparian zone comparable to the drop in mean river level and expansion of the lower riparian zone into shallow areas of the channel. The GIs maps showed that the shallow areas of the channel more likely to become vegetated under the scenario flow are located in wide reaches near islands. Some possible ecological consequences of the scenario flow include a greater area of riparian habitat, reduced flow velocity and sedimentation in shallow channels leading to channel deactivation, increased island visitation and nest predation by predatory mammals due to loss of a water barrier between some islands and banks, and larger populations of alien plant species in the new riparian vegetation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70018761','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70018761"><span>Simulation of interaction between ground water in an alluvial aquifer and surface water in a large braided river</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Leake, S.A.; Lilly, M.R.</p> <p>1995-01-01</p> <p>The Fairbanks, Alaska, area has many contaminated sites in a shallow alluvial aquifer. A ground-water flow model is being developed using the MODFLOW finite-difference ground-water flow model program with the River Package. The modeled area is discretized in the horizontal dimensions into 118 rows and 158 columns of approximately 150-meter square cells. The fine grid spacing has the advantage of providing needed detail at the contaminated sites and surface-water features that bound the aquifer. However, the fine spacing of cells adds difficulty to simulating interaction between the aquifer and the large, braided Tanana River. In particular, the assignment of a river head is difficult if cells are much smaller than the river width. This was solved by developing a procedure for interpolating and extrapolating river head using a river distance function. Another problem is that future transient simulations would require excessive numbers of input records using the current version of the River Package. The proposed solution to this problem is to modify the River Package to linearly interpolate river head for time steps within each stress period, thereby reducing the number of stress periods required.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMEP31B0936S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMEP31B0936S"><span>Numerical Simulation of Missouri River Bed Evolution Downstream of Gavins Point Dam</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sulaiman, Z. A.; Blum, M. D.; Lephart, G.; Viparelli, E.</p> <p>2016-12-01</p> <p>The Missouri River originates in the Rocky Mountains in western Montana and joins the Mississippi River near Saint Louis, Missouri. In the 1900s dam construction and river engineering works, such as river alignment, narrowing and bank protections were performed in the Missouri River basin to control the flood flows, ensure navigation and use the water for agricultural, industrial and municipal needs, for the production of hydroelectric power generation and for recreation. These projects altered the flow and the sediment transport regimes in the river and the exchange of sediment between the river and the adjoining floodplain. Here we focus on the long term effect of dam construction and channel narrowing on the 1200 km long reach of the Missouri River between Gavins Point Dam, Nebraska and South Dakota, and the confluence with the Mississippi River. Field observations show that two downstream migrating waves of channel bed degradation formed in this reach in response to the changes in flow regime, sediment load and channel geometry. We implemented a one dimensional morphodynamic model for large, low slope sand bed rivers, we validated the model at field scale by comparing the numerical results with the available field data and we use the model to 1) predict the magnitude and the migration rate of the waves of degradation at engineering time scales ( 150 years into the future), 2) quantify the changes in the sand load delivered to the Mississippi River, where field observations at Thebes, i.e. downstream of Saint Louis, suggest a decline in the mean annual sand load in the past 50 years, and 3) identify the role of the main tributaries - Little Sioux River, Platte River and Kansas River - on the wave migration speed and the annual sand load in the Missouri River main channel.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H21L..06G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H21L..06G"><span>Forward to the Future: Estimating River Discharge with McFLI</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gleason, C. J.; Durand, M. T.; Garambois, P. A.</p> <p>2016-12-01</p> <p>The global surface water budget is still poorly understood, and improving our understanding of freshwater budgets requires coordination between in situ observations, models, and remote sensing. The upcoming launch of the NASA/CNES Surface Water and Ocean Topography (SWOT) satellite has generated considerable excitement as a new tool enabling hydrologists to tackle some of the most pressing questions facing their discipline. One question in particular which SWOT seems well suited to answer is river discharge (flow rate) estimation in ungauged basins: SWOT's anticipated measurements of river surface height and area have ushered in a new technique in hydrology- what we are here calling Mass conserved Flow Law Inversions, or McFLI. McFLI algorithms leverage classic hydraulic flow expressions (e.g. Manning's Equation, hydraulic geometry) within mass conserved river reaches to construct a simplified but still underconstrained system of equations to be solved for an unknown discharge. Most existing McFLI techniques have been designed to take advantage of SWOT's measurements and Manning's Equation: SWOT will observe changes in cross sectional area and river surface slope over time, so the McFLI need only solve for baseflow area and Manning's roughness coefficient. Recently published preliminary results have indicated that McFLI can be a viable tool in a global hydrologist's toolbox (discharge errors less than 30% as compared to gauges are possible in most cases). Therefore, we here outline the progress to date for McFLI techniques, and highlight three key areas for future development: 1) Maximize the accuracy and robustness of McFLI by incorporating ancillary data from satellites, models, and in situ observations. 2) Develop new McFLI techniques using novel or underutilized flow laws. 3) Systematically test McFLI to define different inversion classes of rivers with well-defined error budgets based on geography and available data for use in gauged and ungauged basins alike.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H13D1576L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H13D1576L"><span>Influence of the Nogales International Wastewater Treatment Plant on surface water in the Santa Cruz River and local aquifers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>LaBrie, H. M.; Brusseau, M. L.; Huth, H.</p> <p>2015-12-01</p> <p>As water resources become limited in Arizona due to drought and excessive use of ground water, treated wastewater effluent is becoming essential in creating natural ecosystems and recharging the decreasing groundwater supplies. Therefore, future water supplies are heavily dependent of the flow (quantity) and quality of the treated effluent. The Nogales International Wastewater Treatment Plant (NIWTP) releases treated wastewater from both Nogales, Arizona and Nogales, Sonora, Mexico into the Santa Cruz River. This released effluent not only has the potential to impact surface water, but also groundwater supplies in Southern Arizona. In the recent past, the NIWTP has had reoccurring issues with elevated levels of cadmium, in addition to other, more infrequent, releases of high amounts of other metals. The industrial demographic of the region, as well as limited water quality regulations in Mexico makes the NIWTP and its treated effluent an important area of study. In addition, outdated infrastructure can potentially lead to damaging environmental impacts, as well as human health concerns. The Santa Cruz River has been monitored and studied in the past, but in recent years, there has been a halt in research regarding the state of the river. Data from existing water quality databases and recent sampling reports are used to address research questions regarding the state of the Santa Cruz River. These questions include: 1) How will change in flow eventually impact surface water and future groundwater supplies 2) What factors influence this flow (such as extreme flooding and drought) 3) What is the impact of effluent on surface water quality 4) Can changes in surface water quality impact groundwater quality 5) How do soil characteristics and surface flow impact the transport of released contaminants Although outreach to stakeholders across the border and updated infrastructure has improved the quality of water in the river, there are many areas to improve upon as the demand for treated wastewater increases.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014HESS...18.4509R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014HESS...18.4509R"><span>Climate change and wetland loss impacts on a western river's water quality</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Records, R. M.; Arabi, M.; Fassnacht, S. R.; Duffy, W. G.; Ahmadi, M.; Hegewisch, K. C.</p> <p>2014-11-01</p> <p>An understanding of potential stream water quality conditions under future climate is critical for the sustainability of ecosystems and the protection of human health. Changes in wetland water balance under projected climate could alter wetland extent or cause wetland loss (e.g., via increased evapotranspiration and lower growing season flows leading to reduced riparian wetland inundation) or altered land use patterns. This study assessed the potential climate-induced changes to in-stream sediment and nutrient loads in the snowmelt-dominated Sprague River, Oregon, western US. Additionally, potential water quality impacts of combined changes in wetland water balance and wetland area under future climatic conditions were evaluated. The study utilized the Soil and Water Assessment Tool (SWAT) forced with statistical downscaling of general circulation model (GCM) data from the Coupled Model Intercomparison Project 5 (CMIP5) using the Multivariate Adaptive Constructed Analogs (MACA) method. Our findings suggest that, in the Sprague River, (1) mid-21st century nutrient and sediment loads could increase significantly during the high-flow season under warmer, wetter climate projections or could change only nominally in a warmer and somewhat drier future; (2) although water quality conditions under some future climate scenarios and no wetland loss may be similar to the past, the combined impact of climate change and wetland losses on nutrient loads could be large; (3) increases in stream total phosphorus (TP) concentration with wetland loss under future climate scenarios would be greatest at high-magnitude, low-probability flows; and (4) loss of riparian wetlands in both headwaters and lowlands could increase outlet TP loads to a similar degree, but this could be due to distinctly different mechanisms in different parts of the watershed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2012/1133/pdf/ofr20121133.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2012/1133/pdf/ofr20121133.pdf"><span>An environmental streamflow assessment for the Santiam River basin, Oregon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Risley, John C.; Wallick, J. Rose; Mangano, Joseph F.; Jones, Krista L.</p> <p>2012-01-01</p> <p>The Santiam River is a tributary of the Willamette River in northwestern Oregon and drains an area of 1,810 square miles. The U.S. Army Corps of Engineers (USACE) operates four dams in the basin, which are used primarily for flood control, hydropower production, recreation, and water-quality improvement. The Detroit and Big Cliff Dams were constructed in 1953 on the North Santiam River. The Green Peter and Foster Dams were completed in 1967 on the South Santiam River. The impacts of the structures have included a decrease in the frequency and magnitude of floods and an increase in low flows. For three North Santiam River reaches, the median of annual 1-day maximum streamflows decreased 42–50 percent because of regulated streamflow conditions. Likewise, for three reaches in the South Santiam River basin, the median of annual 1-day maximum streamflows decreased 39–52 percent because of regulation. In contrast to their effect on high flows, the dams increased low flows. The median of annual 7-day minimum flows in six of the seven study reaches increased under regulated streamflow conditions between 60 and 334 percent. On a seasonal basis, median monthly streamflows decreased from February to May and increased from September to January in all the reaches. However, the magnitude of these impacts usually decreased farther downstream from dams because of cumulative inflow from unregulated tributaries and groundwater entering the North, South, and main-stem Santiam Rivers below the dams. A Wilcox rank-sum test of monthly precipitation data from Salem, Oregon, and Waterloo, Oregon, found no significant difference between the pre-and post-dam periods, which suggests that the construction and operation of the dams since the 1950s and 1960s are a primary cause of alterations to the Santiam River basin streamflow regime. In addition to the streamflow analysis, this report provides a geomorphic characterization of the Santiam River basin and the associated conceptual framework for assessing possible geomorphic and ecological changes in response to river-flow modifications. Suggestions for future biomonitoring and investigations are also provided. This study was one in a series of similar tributary streamflow and geomorphic studies conducted for the Willamette Sustainable Rivers Project. The Sustainable Rivers Project is a national effort by the USACE and The Nature Conservancy to develop environmental flow requirements in regulated river systems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JHyd..544..327E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JHyd..544..327E"><span>Climate-induced alteration of hydrologic indicators in the Athabasca River Basin, Alberta, Canada</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eum, Hyung-Il; Dibike, Yonas; Prowse, Terry</p> <p>2017-01-01</p> <p>The hydrologic response of the Athabasca River Basin (ARB) in Alberta to projected changes in the future climate is investigated using the Variable Infiltration Capacity (VIC) process-based and distributed hydrologic model. The model forcings are derived from a selected set of GCMs from the latest Coupled Model Intercomparison Project (CMIP5) statistically downscaled to a higher resolution (10 km) over Canada. Twelve hydrologic indicators that represent the magnitude and timing of the hydrologic regimes are evaluated for three 30-year time periods centered at the 1990s, 2050s and 2080s to identify significant alterations of hydrologic regimes between the reference and the two future periods using a t-test at 5% significance level. Hydrologic alteration factors (HAF) are also evaluated for each hydrologic indicator using the range of variability approach (RVA) to investigate projected changes in the distribution of these indicators. The results show increases in spring and winter flows for the two future periods at all hydrometric stations within the basin, resulting in an extended period of spring freshet. A higher rate of increase is projected for the stations located at the upper reach of the river because of the combined effects of increased precipitation and earlier snowmelt resulting from a warming climate. By contrast, summer flows are projected to decrease by up to 21% on average in the 2080s over most of the mainstem stations because of earlier snowmelt, increased evapotranspiration and no significant increase in summer precipitation. A water-management rule that optimizes impacts of water withdrawal from the lower reach of the Athabasca River under the current condition is also applied to the future scenarios to assess its relative performance under the projected climate conditions. The results indicate possible improvement in the water resources system performance in terms of increased reliability and resilience and reduced vulnerability during the two future periods as compared with those in the reference period mainly because of the projected increases in spring and winter flows, which has the potential to offset an expected future water deficit.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NHESS..16.2683R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NHESS..16.2683R"><span>The December 2012 Mayo River debris flow triggered by Super Typhoon Bopha in Mindanao, Philippines: lessons learned and questions raised</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rodolfo, Kelvin S.; Lagmay, A. Mahar F.; Eco, Rodrigo C.; Herrero, Tatum Miko L.; Mendoza, Jerico E.; Minimo, Likha G.; Santiago, Joy T.</p> <p>2016-12-01</p> <p>Category 5 Super Typhoon Bopha, the world's worst storm of 2012, formed abnormally close to the Equator, and its landfall on Mindanao set the record proximity to the Equator for its category. Its torrential rains generated an enormous debris flow in the Mayo River watershed that swept away much of the village Andap in the New Bataan municipality, burying areas under rubble as thick as 9 m and killing 566 people. Established in 1968, New Bataan had never experienced super typhoons and debris flows. This unfamiliarity compounded the death and damage. We describe Bopha's history, debris flows and the Mayo River disaster, and then we discuss how population growth contributed to the catastrophe, as well as the possibility that climate change may render other near-Equatorial areas vulnerable to hazards brought on by similar typhoons. Finally, we recommend measures to minimize the loss of life and damage to property from similar future events.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/37774','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/37774"><span>Gravel addition as a habitat restoration technique for tailwaters</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Ryan McManamay; D. Orth; Charles Dolloff; Mark Cantrell</p> <p>2010-01-01</p> <p>We assessed the efficacy of passive gravel addition at forming catostomid spawning habitat under various flow regimes in the Cheoah River, a high-gradient tailwater river in North Carolina. The purpose was to provide a case study that included recommendations for future applications. A total of 76.3 m3 (162 tons) of washed gravel (10-50 mm) was passively dumped down...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PIAHS.378...23K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PIAHS.378...23K"><span>Assessment of impacts of climate change on surface water availability using coupled SWAT and WEAP models: case of upper Pangani River Basin, Tanzania</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kishiwa, Peter; Nobert, Joel; Kongo, Victor; Ndomba, Preksedis</p> <p>2018-05-01</p> <p>This study was designed to investigate the dynamics of current and future surface water availability for different water users in the upper Pangani River Basin under changing climate. A multi-tier modeling technique was used in the study, by coupling the Soil and Water Assessment Tool (SWAT) and Water Evaluation And Planning (WEAP) models, to simulate streamflows under climate change and assess scenarios of future water availability to different socio-economic activities by year 2060. Six common Global Circulation Models (GCMs) from WCRP-CMIP3 with emissions Scenario A2 were selected. These are HadCM3, HadGEM1, ECHAM5, MIROC3.2MED, GFDLCM2.1 and CSIROMK3. They were downscaled by using LARS-WG to station scale. The SWAT model was calibrated with observed data and utilized the LARS-WG outputs to generate future streamflows before being used as input to WEAP model to assess future water availability to different socio-economic activities. GCMs results show future rainfall increase in upper Pangani River Basin between 16-18 % in 2050s relative to 1980-1999 periods. Temperature is projected to increase by an average of 2 °C in 2050s, relative to baseline period. Long-term mean streamflows is expected to increase by approximately 10 %. However, future peak flows are estimated to be lower than the prevailing average peak flows. Nevertheless, the overall annual water demand in Pangani basin will increase from 1879.73 Mm3 at present (2011) to 3249.69 Mm3 in the future (2060s), resulting to unmet demand of 1673.8 Mm3 (51.5 %). The impact of future shortage will be more severe in irrigation where 71.12 % of its future demand will be unmet. Future water demands of Hydropower and Livestock will be unmet by 27.47 and 1.41 % respectively. However, future domestic water use will have no shortage. This calls for planning of current and future surface water use in the upper Pangani River Basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012HESSD...9.6689M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012HESSD...9.6689M"><span>Hydrology of the Po River: looking for changing patterns in river discharge</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Montanari, A.</p> <p>2012-05-01</p> <p>Scientists and public administrators are devoting increasing attention to the Po River, in Italy, in view of concerns related to the impact of increasing urbanisation and exploitation of water resources. A better understanding of the hydrological regime of the river is necessary to improve water resources management and flood protection. In particular, the analysis of the effects of hydrological and climatic change is crucial for planning sustainable development and economic growth. An extremely interesting issue is to inspect to what extent river flows can be naturally affected by the occurrence of long periods of water abundance or scarcity, which can be erroneously interpreted as irreversible changes due to human impact. In fact, drought and flood periods alternatively occurred in the recent past in the form of long term cycles. This paper presents advanced graphical and analytical methods to gain a better understanding of the temporal distribution of the Po River discharge. In particular, we present an analysis of river flow variability and memory properties to better understand natural patterns and in particular long term changes, which may affect the future flood risk and availability of water resources.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70191171','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70191171"><span>Riparian plant composition along hydrologic gradients in a dryland river basin and implications for a warming climate</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Reynolds, Lindsay; Shafroth, Patrick B.</p> <p>2017-01-01</p> <p>Droughts in dryland regions on all continents are expected to increase in severity and duration under future climate projections. In dryland regions, it is likely that minimum streamflow will decrease with some perennial streams shifting to intermittent flow under climate-driven changes in precipitation and runoff and increases in temperature. Decreasing base flow and shifting flow regimes from perennial to intermittent could have significant implications for stream-dependent biota, including riparian vegetation. In this study, we asked, how do riparian plant communities vary along wet-to-dry hydrologic gradients on small (first–third order) streams? We collected data on geomorphic, hydrologic, and plant community characteristics on 54 stream sites ranging in hydrology from intermittent to perennial flow across the Upper Colorado River Basin (284,898 km2). We found that plant communities varied along hydrologic gradients from high to low elevation between streams, and perennial to intermittent flow. We identified indicator species associated with different hydrologic conditions and suggest how plant communities may shift under warmer, drier conditions. Our results indicate that species richness and cover of total, perennial, wetland, and native plant groups will decrease while annual plants will increase under drying conditions. Understanding how plant communities respond to regional drivers such as hydroclimate requires broad-scale approaches such as sampling across whole river basins. With increasingly arid conditions in many regions of the globe, understanding plant community shifts is key to understanding the future of riparian ecosystems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1913850L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1913850L"><span>UAV based hydromorphological mapping of a river reach to improve hydrodynamic numerical models</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lükő, Gabriella; Baranya, Sándor; Rüther, Nils</p> <p>2017-04-01</p> <p>Unmanned Aerial Vehicles (UAVs) are increasingly used in the field of engineering surveys. In river engineering, or in general, water resources engineering, UAV based measurements have a huge potential. For instance, indirect measurements of the flow discharge using e.g. large-scale particle image velocimetry (LSPIV), particle tracking velocimetry (PTV), space-time image velocimetry (STIV) or radars became a real alternative for direct flow measurements. Besides flow detection, topographic surveys are also essential for river flow studies as the channel and floodplain geometry is the primary steering feature of the flow. UAVs can play an important role in this field, too. The widely used laser based topographic survey method (LIDAR) can be deployed on UAVs, moreover, the application of the Structure from Motion (SfM) method, which is based on images taken by UAVs, might be an even more cost-efficient alternative to reveal the geometry of distinct objects in the river or on the floodplain. The goal of this study is to demonstrate the utilization of photogrammetry and videogrammetry from airborne footage to provide geometry and flow data for a hydrodynamic numerical simulation of a 2 km long river reach in Albania. First, the geometry of the river is revealed from photogrammetry using the SfM method. Second, a more detailed view of the channel bed at low water level is taken. Using the fine resolution images, a Matlab based code, BASEGrain, developed by the ETH in Zürich, will be applied to determine the grain size characteristics of the river bed. This information will be essential to define the hydraulic roughness in the numerical model. Third, flow mapping is performed using UAV measurements and LSPIV method to quantitatively asses the flow field at the free surface and to estimate the discharge in the river. All data collection and analysis will be carried out using a simple, low-cost UAV, moreover, for all the data processing, open source, freely available software will be used leading to a cost-efficient methodology. The results of the UAV based measurements will be discussed and future research ideas will be outlined.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H41E1376T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H41E1376T"><span>Continuous measurements of water surface height and width along a 6.5km river reach for discharge algorithm development</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tuozzolo, S.; Durand, M. T.; Pavelsky, T.; Pentecost, J.</p> <p>2015-12-01</p> <p>The upcoming Surface Water and Ocean Topography (SWOT) satellite will provide measurements of river width and water surface elevation and slope along continuous swaths of world rivers. Understanding water surface slope and width dynamics in river reaches is important for both developing and validating discharge algorithms to be used on future SWOT data. We collected water surface elevation and river width data along a 6.5km stretch of the Olentangy River in Columbus, Ohio from October to December 2014. Continuous measurements of water surface height were supplemented with periodical river width measurements at twenty sites along the study reach. The water surface slope of the entire reach ranged from during 41.58 cm/km at baseflow to 45.31 cm/km after a storm event. The study reach was also broken into sub-reaches roughly 1km in length to study smaller scale slope dynamics. The furthest upstream sub-reaches are characterized by free-flowing riffle-pool sequences, while the furthest downstream sub-reaches were directly affected by two low-head dams. In the sub-reaches immediately upstream of each dam, baseflow slope is as low as 2 cm/km, while the furthest upstream free-flowing sub-reach has a baseflow slope of 100 cm/km. During high flow events the backwater effect of the dams was observed to propagate upstream: sub-reaches impounded by the dams had increased water surface slopes, while free flowing sub-reaches had decreased water surface slopes. During the largest observed flow event, a stage change of 0.40 m affected sub-reach slopes by as much as 30 cm/km. Further analysis will examine height-width relationships within the study reach and relate cross-sectional flow area to river stage. These relationships can be used in conjunction with slope data to estimate discharge using a modified Manning's equation, and are a core component of discharge algorithms being developed for the SWOT mission.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70120900','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70120900"><span>Effects of flow alterations on trout, angling, and recreation in the Chattahoochee River between Buford Dam and Peachtree Creek</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nestler, John M.; Milhouse, Robert T.; Troxel, Jay; Fritschen, Janet A.</p> <p>1985-01-01</p> <p>In 1974 county governments in the Atlanta vicinity realized that demands on the Chattahoochee River for water supply plus the streamflow required for water quality nearly equaled the minimum flow in the river. Increased demands for water supply in the following years could not be supplied under the then existing flow regime in the river. In response to the anticipated shortage of water, the Atlanta Regional Commission, a multicounty agency responsible for comprehensive regional planning in the Atlanta region, was contracted to prepare water demand projections to the year 2010 and identify alternatives for meeting projected water demands. The results of this study are published in an extensive final report, the Metropolitan Atlanta Area Water Resources Management Study (1981). Requests for copies should be directed to the District Engineer, Savannah District. Many of the identified alternatives to increase future water supply for the Atlanta area would result in modifications to the present flow regime within the Chattahoochee River between Buford Dam (river mile 348.3) and its confluence with Peachtree Creek (river mile 300.5). The present preferred alternative is construction of a reregulation dam at about river mile 342. The proposed reregulation dam would release a much more constant flow than the peaking flows presently released from Buford Dam (generally, a maximum release of approximately 9000 cfs or minimum release of about 550 cfs) by storing the generation releases from Buford Dam for gradual release during non-generation periods. The anticipated minimum release from the rereg dam would he approximately 1U5U cfs (based on contractual obligations to the Southeast Power Administration to supply a minimum of 11 hours of peaking power per week from Buford Dam). The average annual release from the proposed reregulation dam into the Chattahoochee River would be approximately 2000 cfs (based on USGS flow records) and the median release would he approximately 1500 cfs (value obtained from Savannah District). The proposed reregulation dam would have sufficient storage to provide some opportunity for flow management to optimize uses other than water supply and water quality. Flow modifications (and resultant water quality changes) within this reach of the Chattahoochee River to meet increased demands for water supply may have an effect on other beneficial uses of this important natural resource. In addition to supplying a significant proportion of the water supply for metropolitan Atlanta and providing for water quality, the Chattahoochee River also is used extensively for recreation and supports a valuable trout fishery. Altered flows in the channel to meet water supply needs may have an impact on river recreation and trout habitat.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.1622S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.1622S"><span>The role of glaciers for Swiss hydropower production</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schaefli, Bettina; Manso, Pedro; Fischer, Mauro; Huss, Matthias</p> <p>2016-04-01</p> <p>In Switzerland, hydropower represents over 50% of the total annual electricity production. Given the Alpine setting of the country, this hydropower production (HPP) strongly relies on the natural storage of discharge in form of ice and snow over months to decades. The sensitivity of glacier-fed HPP systems with respect to climate change depends on how the today's production and the infrastructure design relies on the seasonal streamflow delay expected from the natural storage effect of snow and ice. For low-head run-of-river HPP plants built on large lowland rivers, the ongoing glacier retreat (resulting in strong summer melt) currently sustains higher flows during summer months, an effect that will certainly be reduced once the glaciers will have reached a critical size. This effect will also modify the inflow to the large storage HPP plants that have been designed to shift large amounts of meltwater inflows from summer to winter. The management of these reservoirs will certainly have to be adapted to future inflow patterns. An interesting case are high-head run-of-river plants (with heads from 100 to 1100 m) that short-circuit a given river reach. Future regime shifts with less sustained summer flow and more concentrated spring melt flows might critically reduce the annual production due to intake overflow during spring and reduced flow during summer. In this work, we discuss the role of glaciers for these different HPP types in detail, including an overview of how glacier retreat might influence their production. This comprehensive study synthesizes up-to-date estimations of glacier mass change since the 1980s and its influence on high Alpine discharge regimes and state-of-the art simulations of potential future glacier discharge regimes. We also attempt an extrapolation to the country level based on a hydropower GIS database that has been developed for economic purposes. Ongoing Swiss research on sediment production and management might complete this picture with the role of glacier sediment delivery for hydropower operation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70176474','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70176474"><span>Geomorphic change and sediment transport during a small artificial flood in a transformed post-dam delta: The Colorado River delta, United States and Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mueller, Erich R.; Schmidt, John C.; Topping, David J.; Shafroth, Patrick B.; Rodríguez-Burgueño, Jesús Eliana; Ramírez-Hernández, Jorge; Grams, Paul E.</p> <p>2017-01-01</p> <p>The Colorado River delta is a dramatically transformed landscape. Major changes to river hydrology and morpho-dynamics began following completion of Hoover Dam in 1936. Today, the Colorado River has an intermittent and/or ephemeral channel in much of its former delta. Initial incision of the river channel in the upstream ∼50 km of the delta occurred in the early 1940s in response to spillway releases from Hoover Dam under conditions of drastically reduced sediment supply. A period of relative quiescence followed, until the filling of upstream reservoirs precipitated a resurgence of flows to the delta in the 1980s and 1990s. Flow releases during extreme upper basin snowmelt in the 1980s, flood flows from the Gila River basin in 1993, and a series of ever-decreasing peak flows in the late 1990s and early 2000s further incised the upstream channel and caused considerable channel migration throughout the river corridor. These variable magnitude post-dam floods shaped the modern river geomorphology. In 2014, an experimental pulse-flow release aimed at rejuvenating the riparian ecosystem and understanding hydrologic dynamics flowed more than 100 km through the length of the delta’s river corridor. This small artificial flood caused localized meter-scale scour and fill of the streambed, but did not cause further incision or significant bank erosion because of its small magnitude. Suspended-sand-transport rates were initially relatively high immediately downstream from the Morelos Dam release point, but decreasing discharge from infiltration losses combined with channel widening downstream caused a rapid downstream reduction in suspended-sand-transport rates. A zone of enhanced transport occurred downstream from the southern U.S.-Mexico border where gradient increased, but effectively no geomorphic change occurred beyond a point 65 km downstream from Morelos Dam. Thus, while the pulse flow connected with the modern estuary, deltaic sedimentary processes were not restored, and relatively few new open surfaces were created for establishment of native riparian vegetation. Because water in the Colorado River basin is completely allocated, exceptional floods from the Gila River basin are the most likely mechanism for major changes to delta geomorphology for the foreseeable future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70196355','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70196355"><span>Long-term monitoring data provide evidence of declining species richness in a river valued for biodiversity conservation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Freeman, Mary C.; Hagler, Megan M.; Bumpers, Phillip M.; Wheeler, Kit; Wengerd, Seth J.; Freeman, Byron J.</p> <p>2017-01-01</p> <p>Free-flowing river segments provide refuges for many imperiled aquatic biota that have been extirpated elsewhere in their native ranges. These biodiversity refuges are also foci of conservation concerns because species persisting within isolated habitat fragments may be particularly vulnerable to local environmental change. We have analyzed long-term (14- and 20-y) survey data to assess evidence of fish species declines in two southeastern U.S. rivers where managers and stakeholders have identified potentially detrimental impacts of current and future land uses. The Conasauga River (Georgia and Tennessee) and the Etowah River (Georgia) form free-flowing headwaters of the extensively dammed Coosa River system. These rivers are valued in part because they harbor multiple species of conservation concern, including three federally endangered and two federally threatened fishes. We used data sets comprising annual surveys for fish species at multiple, fixed sites located at river shoals to analyze occupancy dynamics and temporal changes in species richness. Our analyses incorporated repeated site-specific surveys in some years to estimate and account for incomplete species detection, and test for species-specific (rarity, mainstem-restriction) and year-specific (elevated frequencies of low- or high-flow days) covariates on occupancy dynamics. In the Conasauga River, analysis of 26 species at 13 sites showed evidence of temporal declines in colonization rates for nearly all taxa, accompanied by declining species richness. Four taxa (including one federally endangered species) had reduced occupancy across the Conasauga study sites, with three of these taxa apparently absent for at least the last 5 y of the study. In contrast, a similar fauna of 28 taxa at 10 sites in the Etowah River showed no trends in species persistence, colonization, or occupancy. None of the tested covariates showed strong effects on persistence or colonization rates in either river. Previous studies and observations identified contaminants, nutrient loading, or changes in benthic habitat as possible causes for fish species declines in the Conasauga River. Our analysis provides baseline information that could be used to assess effectiveness of future management actions in the Conasauga or Etowah rivers, and illustrates the use of dynamic occupancy models to evaluate evidence of faunal decline from time-series data.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2013/3016/fs2013-3016.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2013/3016/fs2013-3016.pdf"><span>Effects of past and future groundwater development on the hydrologic system of Verde Valley, Arizona</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Garner, Bradley D.; Pool, D.R.</p> <p>2013-01-01</p> <p>Communities in central Arizona’s Verde Valley must manage limited water supplies in the face of rapidly growing populations. Developing groundwater resources to meet human needs has raised questions about the effects of groundwater withdrawals by pumping on the area’s rivers and streams, particularly the Verde River. U.S. Geological Survey hydrologists used a regional groundwater flow model to simulate the effects of groundwater pumping on streamflow in the Verde River. The study found that streamflow in the Verde River between 1910 and 2005 had been reduced as the result of streamflow depletion by groundwater pumping, also known as capture. Additionally, using three hypothetical scenarios for a period from 2005 to 2110, the study’s findings suggest that streamflow reductions will continue and may increase in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.4421W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.4421W"><span>Assessing river-groundwater exchange fluxes of the Wairau River, New Zealand</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilson, Scott; Woehling, Thomas; Davidson, Peter</p> <p>2014-05-01</p> <p>Allocation limits in river-recharged aquifers have traditionally been based on static observations of river gains and losses undertaken when river flow is low. This approach to setting allocation limits does not consider the dynamic relationship between river flows and groundwater levels. Predicting groundwater availability based on a better understanding of coupled river - aquifer systems opens the possibility for dynamic groundwater allocation approaches. Numerical groundwater models are most commonly used for regional scale allocation assessments. Using these models for predicting future system states is challenging, particularly under changing management and climate scenarios. The large degree of uncertainty associated with these predictions is caused by insufficient knowledge about the heterogeneity of subsurface flow characteristics, ineffective monitoring designs, and the inability to confidently predict the spatially and temporally varying river - groundwater exchange fluxes. These uncertainties are characteristic to many coupled surface water - groundwater systems worldwide. Braided river systems, however, create additional challenges due to their highly dynamic morphological character and mobile beds which also make river flow measurements extremely difficult. This study focuses on the characterization of river - groundwater exchange fluxes along a section of the Wairau River in the Northwest of the South Island of New Zealand. The braided river recharges the Wairau Aquifer which is an important source for irrigation and municipal water requirements of the city of Blenheim. The Wairau Aquifer is hosted by the highly permeable Rapaura Formation gravels that extend to a depth of about 20 to 30 m. However, the overall thickness of the alluvial sequence forming the Wairau Plain may be up to 500 m. The landuse in the area is mainly grapes but landsurface recharge to the aquifer is considered to be considerably smaller than the recharge from the Wairau river. This study aims at the assessment of river-groundwater exchange fluxes and presents first results from data mining and analysis of river flow records, stage gaugings, groundwater head data, pumping test, and the sampling of spring flows. In addition, a methodology is presented that will allow the prediction of transient river exchange fluxes by using a Modflow model, global optimisation techniques, and techniques for quantifying predictive uncertainty which have been recently developed (Wöhling et al 2013). A long-term goal of the study is the reduction of predictive uncertainty of model predictions by optimal design of sensor networks as well as the assessment of this utility by different observation types. Preliminary results indicate that about 7 cumec from the Wairau River is recharged to the aquifer under low flow conditions. A similar volume of groundwater re-emerges as springs where groundwater is forced upwards by the confining Dillons Point Formation. References Wöhling, Th., Gosses, M.J., Leyes Pérez, M., Geiges, A., Moore, C.R., Osenbrück, K., Scott, D.M. (2013). Optimizing monitoring design to increase predictive reliability of groundwater flow models at different scales. Geophysical Research Abstracts Vol. 15, EGU2013-3981, EGU General Assembly 2013.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.8689M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.8689M"><span>Upper air teleconnections to Ob River flows and tree rings</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meko, David; Panyushkina, Irina; Agafonov, Leonid</p> <p>2015-04-01</p> <p>The Ob River, one of the world's greatest rivers, with a catchment basin about the size of Western Europe, contributes 12% or more of the annual freshwater inflow to the Arctic Ocean. The input of heat and fresh water is important to the global climate system through effects on sea ice, salinity, and the thermohaline circulation of the ocean. As part of a tree-ring project to obtain multi-century long information on variability of Ob River flows, a network of 18 sites of Pinus, Larix, Populus and Salix has been collected along the Ob in the summers of 2013 and 2014. Analysis of collections processed so far indicates a significant relationship of tree-growth to river discharge. Moderation of the floodplain air temperature regime by flooding appears to be an important driver of the tree-ring response. In unraveling the relationship of tree-growth to river flows, it is important to identify atmospheric circulation features directly linked to observed time series variations of flow and tree growth. In this study we examine statistical links between primary teleconnection modes of Northern Hemisphere upper-air (500 mb) circulation, Ob River flow, and tree-ring chronologies. Annual discharge at the mouth of the Ob River is found to be significantly positively related to the phase of the East Atlantic (EA) pattern, the second prominent mode of low-frequency variability over the North Atlantic. The EA pattern, consisting of a north-south dipole of pressure-anomaly centers spanning the North Atlantic from east to west, is associated with a low-pressure anomaly centered over the Ob River Basin, and with a pattern of positive precipitation anomaly of the same region. The positive correlation of discharge and EA is consistent with these know patterns, and is contrasted with generally negative (though smaller) correlations between EA and tree-ring chronologies. The signs of correlations are consistent with a conceptual model of river influence on tree growth through air temperature. Future work aims at combining the tree-ring samples from living trees and remnant wood to reconstruction to quantitiative reconstruction of annual flow over the past millennium.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.water.usgs.gov/wri004227','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/wri004227"><span>Preliminary hydraulic analysis and implications for restoration of Noyes Slough, Fairbanks, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Burrows, Robert L.; Langley, Dustin E.; Evetts, David M.</p> <p>2000-01-01</p> <p>The present-day channels of the Chena River and Noyes Slough in downtown Fairbanks, Alaska, were formed as sloughs of the Tanana River, and part of the flow of the Tanana River occupied these waterways. Flow in these channels was reduced after the completion of Moose Creek Dike in 1945, and flow in the Chena River was affected by regulation from the Chena River Lakes Flood Control Project, which was completed in 1980. In 1981, flow in the Chena River was regulated for the first time by Moose Creek Dam, located about 20 miles upstream from Fairbanks. Constructed as part of the Chena River Lakes Flood Control Project, the dam was designed to reduce maximum flows to 12,000 cubic feet per second in downtown Fairbanks. Cross-section measurements made near the entrance to Noyes Slough show that the channel bed of the Chena River has been downcutting, thereby reducing the magnitude and duration of flow in the slough. Consequently the slough slowly is drying up. The slough provides habitat for wildlife such as ducks, beaver, and muskrat and is a fishery for anadromous and other resident species. Beavers have built 10 dams in the slough. Declining flow in the slough may endanger the remaining habitat. Residents of the community wish to restore flow in Noyes Slough to create a clean, flowing waterway during normal summer flows. The desire is to enhance the slough as a fishery and habitat for other wildlife and for recreational boating. During this study, existing and new data were compiled to determine past and present hydraulic interaction between the Chena River and Noyes Slough. The U.S. Army Corps of Engineers Hydrologic Engineering Center River Analysis System (HECRAS) computer program was used to construct a model to use in evaluating alternatives for increasing flow in the slough. Under present conditions, the Chena must flow at about 2,400 cubic feet per second or more for flow to enter Noyes Slough. In an average year, water flows in Noyes Slough for 106 days during the open-water season, and maximum flow is about 1,050 cubic feet per second. The model was used to test a single method of increasing flow in Noyes Slough. A modified channel 40 feet wide and about 2 feet deeper within the existing slough channel was simulated by changing the cross-section geometry in the HECRAS model. The resulting model showed that flow in such a modified slough channel would begin at a flow of about 830 cubic feet per second in the Chena River and would increase to a maximum flow of about 1,440 cubic feet per second. In an average year, flow would continue for 158 days during the open-water season. Theoretically, enlarging the slough channel by lowering its bed could increase flow, but other solutions are possible. Possible obstacles to excavating the channel, such as bridges and utility crossings, and the destruction of desirable features such as beaver dams were not considered in the study. Further engineering and economic analyses would be needed to assess the cost of excavation and future maintenance of the modified channel. A computer-modeling program such as HECRAS may provide a means for testing other solutions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1958/0062/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1958/0062/report.pdf"><span>History of natural flows--Kansas River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Leeson, Elwood R.</p> <p>1958-01-01</p> <p>Through its Water Resources Division, the United States Geological Survey has become the major water-resources historian for the nation. The Geological Survey's collection of streamflow records in Kansas began on a very small scale in 1895 in response to some early irrigation interest, Since that time the program has grown, and we now have about 21 350 station-years of record accumulated. A station-year of record is defined as a continuous record of flow collected at a fixed point for a period of one year. Volume of data at hand, however, is not in itself an, adequate measure of its usefullness. An important element in historical streamflow data which enhances its value as a tool for the prediction of the future is the length of continuous records available in the area being studied. The records should be of sufficient length that they may be regarded as a reasonable sample of what has gone before and may be expected in the future. Table 1 gives a graphical inventory of the available streamflow records in Kansas. It shows that, in general, there is a fair coverage of stations with records of about thirty-seven years in length, This is not a long period as history goes but it does include considerable experience with floods and droughts.Although a large quantity of data on Kansas streamflow has been accumulated, hydrologists and planning engineers find that stream flow information for many areas of the State is considerably less than adequate. The problem of obtaining adequate coverage has been given careful study by the Kansas Water Resources Board in cooperation with the U. S. Geological Survey and a report entitled "Development of A Balanced Stream-Gaging Program For Kansas", has been published by the Board as Bulletin No. 4, That report presents an analysis of the existing stream-gaging program and recommendations for a program to meet the rapidly expanding needs for more comprehensive basic data.The Kansas River is formed near Junction City, Kansas, by the confluence of the Smoky Hill and Republican Rivers, From that point the river flows eastward about 175 miles to Kansas City where it empties into the Missouri River. The basic history of its natural flow can be depicted in general by the records from three gaging stations. The one at Bonner Springs, about 21 miles upstream from the mouth, may be considered as representing the total outflow from the basin; the one at Ogden, about 8 miles downstream from the confluence of the Smoky Hill and Republican Rivers, may be considered as representing the combined contribution of those streams to the Kansas River flow; and the one at Topeka, being only about 16 river miles nearer to Ogden than to Bonner Springs, may be considered as representing flows at the mid-point along the river.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2012/5234/SIR12-5234.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2012/5234/SIR12-5234.pdf"><span>Characterization of streamflow, water quality, and instantaneous dissolved solids, selenium, and uranium loads in selected reaches of the Arkansas River, southeastern Colorado, 2009-2010</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ivahnenko, Tamara; Ortiz, Roderick F.; Stogner, Sr., Robert W.</p> <p>2013-01-01</p> <p>As a result of continued water-quality concerns in the Arkansas River, including metal contamination from historical mining practices, potential effects associated with storage and movement of water, point- and nonpoint-source contamination, population growth, storm-water flows, and future changes in land and water use, the Arkansas River Basin Regional Resource Planning Group (RRPG) developed a strategy to address these issues. As such, a cooperative strategic approach to address the multiple water-quality concerns within selected reaches of the Arkansas River was developed to (1) identify stream reaches where stream-aquifer interactions have a pronounced effect on water quality and (or) where reactive transport, and physical and (or) chemical alteration of flow during conveyance, is occurring, (2) quantify loading from point sources, and (3) determine source areas and mass loading for selected constituents. (To see the complete abstract, open Report PDF.)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.water.usgs.gov/ofr2004-1308/','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/ofr2004-1308/"><span>Water-use data for the Red River of the North Basin, North Dakota, Minnesota, and South Dakota, 1979-2001</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Macek-Rowland, Kathleen M.; Arntson, Allan D.; Ryberg, Karen R.; Dahl, Ann L.; Lieb, Amy</p> <p>2004-01-01</p> <p>The Red River of the North, located in the north-central plains of the United States, plays an important role in population growth and economic development of the region. Because of recent and projected growth in population, industry, and agriculture in the Red River of the North Basin, alternatives to additional water resources will be needed to supplement future water needs. Past and current water-use data are needed to help select the most viable water-resource alternatives. Withdrawal and return flow data were collected from various sources throughout the Red River of the North Basin from 1979 through 2001. The withdrawal data were aggregated by subbasin, monthly totals, and water-use categories. The return flow data were aggregated by subbasin and monthly totals. The Red River of the North Basin was divided into subbasins based on locations of U.S. Geological Survey streamflow-gaging stations and by specifically-identified reaches. Results of the water-use compilation are provided in this report.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/pp1661e/pp1661e.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/pp1661e/pp1661e.pdf"><span>Seismic stability of the Duwamish River Delta, Seattle, Washington</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kayen, Robert E.; Barnhardt, Walter A.</p> <p>2007-01-01</p> <p>The delta front of the Duwamish River valley near Elliott Bay and Harbor Island is founded on young Holocene deposits shaped by sea-level rise, episodic volcanism, and seismicity. These river-mouth deposits are highly susceptible to seismic soil liquefaction and are potentially prone to submarine landsliding and disintegrative flow failure. A highly developed commercial-industrial corridor, extending from the City of Kent to the Elliott Bay/Harbor Island marine terminal facilities, is founded on the young Holocene deposits of the Duwamish River valley. The deposits of this Holocene delta have been shaped not only by relative sea-level rise but also by episodic volcanism and seismicity. Ground-penetrating radar (GPR), cores, in situ testing, and outcrops are being used to examine the delta stratigraphy and to infer how these deposits will respond to future volcanic eruptions and earthquakes in the region. A geotechnical investigation of these river-mouth deposits indicates high initial liquefaction susceptibility during earthquakes, and possibly the potential for unlimited-strain disintegrative flow failure of the delta front.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29751440','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29751440"><span>Impact of forest maintenance on water shortages: Hydrologic modeling and effects of climate change.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Luo, Pingping; Zhou, Meimei; Deng, Hongzhang; Lyu, Jiqiang; Cao, Wenqiang; Takara, Kaoru; Nover, Daniel; Geoffrey Schladow, S</p> <p>2018-02-15</p> <p>The importance of water quantity for domestic and industrial water supply, agriculture, and the economy more broadly has led to the development of many water quantity assessment methods. In this study, surface flow and soil water in the forested upper reaches of the Yoshino River are compared using a distributed hydrological model with Forest Maintenance Module under two scenarios; before and after forest maintenance. We also examine the impact of forest maintenance on these variables during extreme droughts. Results show that surface flow and soil water increased after forest maintenance. In addition, projections of future water resources were estimated using a hydrological model and the output from a 20km mesh Global Climate Model (GCM20). River discharge for the near-future (2015-2039) is similar to that of the present (1979-2003). Estimated river discharge for the future (2075-2099) was found to be substantially more extreme than in the current period, with 12m 3 /s higher peak discharge in August and 7m 3 /s lower in July compared to the discharges of the present period. Soil water for the future is estimated to be lower than for the present and near future in May. The methods discussed in this study can be applied in other regions and the results help elucidate the impact of forests and climate change on water resources. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1414440C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1414440C"><span>A Darwinian mystery: fluctuations in runoff from the la Plata basin (Alexander von Humboldt Medal Lecture)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clarke, R. T.</p> <p>2012-04-01</p> <p>During the voyage of HMS Beagle, Charles Darwin sailed in a small boat along the River Paraná, a major tributary of the la Plata drainage system. He wrote about the occurrence of severe droughts (the latest of which had been termed the "gran seco") alternating with periods of severe flooding. From reports received, he concluded that these events appeared to be cyclic with a period "of about fifteen years". Because extended periods of low flow in Brazilian rivers are of immense economic importance, the presentation describes a search for the material which led Darwin to this conclusion. A prolonged period of low flow in another la Plata tributary - the River Paraguay - not unlike the "gran seco" reported by Darwin, has occurred more recently; if such low flows were to recur in the future, the consequences would be severe for a region where more than 70% of energy is supplied by hydropower. A priori considerations suggest the use of statistical long-memory models for predicting River Paraguay water-levels, and some preliminary results from their use are presented.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H23B1539J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H23B1539J"><span>Fine sediment trapping in river lateral cavities</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Juez, C.; Maechler, G.; Schleiss, A. J.; Franca, M. J.</p> <p>2016-12-01</p> <p>River restoration is nowadays a major issue in the field of hydraulics. The natural course and geometry of the rivers have been artificially changed by human activities for different purposes (land gaining, flood protection, agriculture). From a morphologic point of view, channelized rivers often display a straight path and monotonous river banks. This is in contradiction with natural morphology, where a high diversity can be found across the channel path (meanders) and the banks (pools, riffles). One way to restore rivers consist of transforming the artificial banks by adding macro-roughness elements in the lateral river banks (also called cavities and lateral embayments). The creation of irregularities on the banks causes new flow patterns that diversify the river habitat. However, these lateral cavities may be also responsible of the change of the river morphology, since they may trap the fine sediments travelling within the water. This is particularly important in glacier-fed streams such as the upper Rhone River in Switzerland. These are charged with fine sediments resulting from the erosion of the underlying glaciers bottom. The creation of lateral cavities may affect the sediment and morphological equilibrium of the river since these may trap sediments. This work aims to study the influence of the lateral cavities on the transport of fine sediments in the main channel. A set of laboratory experiments were done which covered a wide range of rectangular cavity configurations. Key parameters such as the flow discharge, the aspect ratio of the cavities and the initial sediment concentration were tested. Surface PIV, sediment samples and turbidity temporal records were collected during the experiments. The trapping efficiency of the cavities and the associated flow patterns were analyzed. The resulting conclusions provide a useful information for the future design of river restoration projects.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70190371','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70190371"><span>A large-scale environmental flow experiment for riparian restoration in the Colorado River delta</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shafroth, Patrick B.; Schlatter, Karen; Gomez-Sapiens, Martha; Lundgren, Erick; Grabau, Matthew R.; Ramirez-Hernandez, Jorge; Rodriguez-Burgeueno, J. Eliana; Flessa, Karl W.</p> <p>2017-01-01</p> <p>Managing streamflow is a widely-advocated approach to provide conditions necessary for seed germination and seedling establishment of trees in the willow family (Salicaceae). Experimental flow releases to the Colorado River delta in 2014 had a primary objective of promoting seedling establishment of Fremont cottonwood (Populus fremontii) and Goodding's willow (Salix gooddingii). We assessed seed germination and seedling establishment of these taxa as well as the non-native tamarisk (Tamarix spp.) and native seepwillow shrubs (Baccharis spp.) in the context of seedling requirements and active land management (land grading, vegetation removal) at 23 study sites along 87 river km. In the absence of associated active land management, experimental flows to the Colorado River delta were minimally successful at promoting establishment of new woody riparian seedlings, except for non-native Tamarix. Our results suggest that the primary factors contributing to low seedling establishment varied across space, but included low or no seed availability in some locations for some taxa, insufficient soil moisture availability during the growing season indicated by deep groundwater tables, and competition from adjacent vegetation (and, conversely, availability of bare ground). Active land management to create bare ground and favorable land grades contributed to significantly higher rates of Salicaceae seedling establishment in a river reach with high groundwater tables. Our results provide insights that can inform future environmental flow deliveries to the Colorado River delta and its ecosystems and other similar efforts to restore Salicaceae taxa around the world.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19380718','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19380718"><span>Sustainable water deliveries from the Colorado River in a changing climate.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barnett, Tim P; Pierce, David W</p> <p>2009-05-05</p> <p>The Colorado River supplies water to 27 million users in 7 states and 2 countries and irrigates over 3 million acres of farmland. Global climate models almost unanimously project that human-induced climate change will reduce runoff in this region by 10-30%. This work explores whether currently scheduled future water deliveries from the Colorado River system are sustainable under different climate-change scenarios. If climate change reduces runoff by 10%, scheduled deliveries will be missed approximately 58% of the time by 2050. If runoff reduces 20%, they will be missed approximately 88% of the time. The mean shortfall when full deliveries cannot be met increases from approximately 0.5-0.7 billion cubic meters per year (bcm/yr) in 2025 to approximately 1.2-1.9 bcm/yr by 2050 out of a request of approximately 17.3 bcm/yr. Such values are small enough to be manageable. The chance of a year with deliveries <14.5 bcm/yr increases to 21% by midcentury if runoff reduces 20%, but such low deliveries could be largely avoided by reducing scheduled deliveries. These results are computed by using estimates of Colorado River flow from the 20th century, which was unusually wet; if the river reverts to its long-term mean, shortfalls increase another 1-1.5 bcm/yr. With either climate-change or long-term mean flows, currently scheduled future water deliveries from the Colorado River are not sustainable. However, the ability of the system to mitigate droughts can be maintained if the various users of the river find a way to reduce average deliveries.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70195396','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70195396"><span>The metabolic regimes of flowing waters</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bernhardt, Emily S.; Heffernan, Jim B.; Grimm, Nancy B.; Stanley, Emily H.; Harvey, Judson; Arroita, M.; Appling, Alison; Cohen, M.J.; McDowell, William H.; Hall, R.O.; Read, Jordan S.; Roberts, B.J.; Stets, Edward; Yackulic, Charles B.</p> <p>2018-01-01</p> <p>The processes and biomass that characterize any ecosystem are fundamentally constrained by the total amount of energy that is either fixed within or delivered across its boundaries. Ultimately, ecosystems may be understood and classified by their rates of total and net productivity and by the seasonal patterns of photosynthesis and respiration. Such understanding is well developed for terrestrial and lentic ecosystems but our understanding of ecosystem phenology has lagged well behind for rivers. The proliferation of reliable and inexpensive sensors for monitoring dissolved oxygen and carbon dioxide is underpinning a revolution in our understanding of the ecosystem energetics of rivers. Here, we synthesize our current understanding of the drivers and constraints on river metabolism, and set out a research agenda aimed at characterizing, classifying and modeling the current and future metabolic regimes of flowing waters.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018E%26ES..121e2091X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018E%26ES..121e2091X"><span>Analysis of the ecological water diversion project in Wenzhou City</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Haibo; Fu, Lei; Lin, Tong</p> <p>2018-02-01</p> <p>As a developed city in China, Wenzhou City has been suffered from bad water quality for years. In order to improve the river network water quality, an ecological water diversion project was designed and executed by the regional government. In this study, an investigation and analysis of the regional ecological water diversion project is made for the purpose of examining the water quality improvements. A numerical model is also established, different water diversion flow rates and sewer interception levels are considered during the simulation. Simulation results reveal that higher flow rate and sewer interception level will greatly improve the river network water quality in Wenzhou City. The importance of the flow rate and interception level has been proved and future work will be focused on increasing the flow rate and upgrading the sewer interception level.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/18575','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/18575"><span>A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Wabash River, Huntington County, Indiana</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Crawford, Charles G.; Wilber, William G.; Peters, James G.</p> <p>1980-01-01</p> <p>A digital model calibrated to conditions in the Wabash River in Huntington County, Ind., was used to predict alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditons, summer and winter low flows. The major point-source waste load affecting the Wabash River in Huntington County is the Huntington wastewater-treatment facility. The most significnt factor potentially affecting the dissolved-oxygen concentration during summer low flows is nitrification. However, nitrification should not be a limiting factor on the allowable nitrogenous and carbonaceous waste loads for the Huntington wastewater-treatment facility during summer low flows if the ammonia-nitrogen toxicity standard for Indiana streams is met. The disolved-oxygen standard for Indiana stream, an average of 5.0 milligrams per liter, should be met during summer and winter low flows if the National Pollution Discharge Elimination System 's 5-day, carbonaceous biochemical-oxygen demands of a monthly average concentration of 30 milligrams per liter and a maximum weekly average of 45 milligrams per liter are not exceeded. </p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H21L..02S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H21L..02S"><span>Analysis of Compound Water Hazard in Coastal Urbanized Areas under the Future Climate</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shibuo, Y.; Taniguchi, K.; Sanuki, H.; Yoshimura, K.; Lee, S.; Tajima, Y.; Koike, T.; Furumai, H.; Sato, S.</p> <p>2017-12-01</p> <p>Several studies indicate the increased frequency and magnitude of heavy rainfalls as well as the sea level rise under the future climate, which implies that coastal low-lying urbanized areas may experience increased risk against flooding. In such areas, where river discharge, tidal fluctuation, and city drainage networks altogether influence urban inundation, it is necessary to consider their potential interference to understand the effect of compound water hazard. For instance, pump stations cannot pump out storm water when the river water level is high, and in the meantime the river water level shall increase when it receives pumped water from cities. At the further downstream, as the tidal fluctuation regulates the water levels in the river, it will also affect the functionality of pump stations and possible inundation from rivers. In this study, we estimate compound water hazard in the coastal low-lying urbanized areas of the Tsurumi river basin under the future climate. We developed the seamlessly integrated river, sewerage, and coastal hydraulic model that can simulate river water levels, water flow in sewerage network, and inundation from the rivers and/or the coast to address the potential interference issue. As a forcing, the pseudo global warming method, which applies the changes in GCM anomaly to re-analysis data, is employed to produce ensemble typhoons to drive the seamlessly integrated model. The results show that heavy rainfalls caused by the observed typhoon generally become stronger under the pseudo global climate condition. It also suggests that the coastal low-lying areas become extensively inundated if the onset of river flooding and storm surge coincides.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2016/5025/sir20165025.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2016/5025/sir20165025.pdf"><span>Effect of a levee setback on aquatic resources using two-dimensional flow and bioenergetics models</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Black, Robert W.; Czuba, Christiana R.; Magirl, Christopher S.; McCarthy, Sarah; Berge, Hans; Comanor, Kyle</p> <p>2016-04-05</p> <p>Watershed restoration is the focus of many resource managers and can include a multitude of restoration actions each with specific restoration objectives. For the White River flowing through the cities of Pacific and Sumner, Washington, a levee setback has been proposed to reconnect the river with its historical floodplain to help reduce flood risks, as well as provide increased habitat for federally listed species of salmonids. The study presented here documents the use of a modeling framework that integrates two-dimensional hydraulic modeling with process-based bioenergetics modeling for predicting how changes in flow from reconnecting the river with its floodplain affects invertebrate drift density and the net rate of energy intake of juvenile salmonids. Modeling results were calculated for flows of 25.9 and 49.3 cubic meters per second during the spring, summer, and fall. Predicted hypothetical future mean velocities and depths were significantly lower and more variable when compared to current conditions. The abundance of low energetic cost and positive growth locations for salmonids were predicted to increase significantly in the study reach following floodplain reconnection, particularly during the summer. This modeling framework presents a viable approach for evaluating the potential fisheries benefits of reconnecting a river to its historical floodplain that integrates our understanding of hydraulic, geomorphology, and organismal biology.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C13A0950W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C13A0950W"><span>Why Does a Shift in Precipitation from Snow Towards Rain Lead to a Decrease in Long Term Mean River Flow?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woods, R. A.</p> <p>2017-12-01</p> <p>Empirical evidence suggests that a shift in precipitation from snow towards rain leads to a strong decrease in long term mean river flow, for a diverse set of snow-dominated catchments across the USA (Berghuijs et al, 2014, Nature Climate Change). Mutually inconsistent hypotheses have been proposed, but no comprehensive explanations are available to explain the observations. Why does less snow apparently lead to less river flow and more evaporation? Is it caused by changes in snow cover, soil freezing, infiltration processes, timing of plant water uptake or something else? Which processes are important where? Solving this scientific puzzle will have significant follow-on impacts for hydrological models, flood risk assessment, seasonal water forecasts, and climate change impacts on water availability, ecosystem functions and other systems impacted by long-term reductions in river flow and evaporation, and their feedbacks to the water cycle.A large international research collaboration (CHIPPER, 35 groups from 15 countries) has formed to make a joint contribution to improved understanding of links between the phase of precipitation and the hydrological cycle, with a particular focus on water balance. This presentation will review progress since 2014 on the topic, outline intended future lines of investigation, and invite feedback and additional collaborations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HydJ...21..257G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HydJ...21..257G"><span>Impact of permafrost development on groundwater flow patterns: a numerical study considering freezing cycles on a two-dimensional vertical cut through a generic river-plain system</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grenier, Christophe; Régnier, Damien; Mouche, Emmanuel; Benabderrahmane, Hakim; Costard, François; Davy, Philippe</p> <p>2013-02-01</p> <p>The impact of glaciation cycles on groundwater flow was studied within the framework of nuclear waste storage in underground geological formations. The eastern section of the Paris Basin (a layered aquifer with impervious/pervious alternations) in France was considered for the last 120 ka. Cold periods corresponded with arid climates. The issue of talik development below water bodies was addressed. These unfrozen zones can maintain open pathways for aquifer recharge. Transient thermal evolution was simulated on a small-scale generic unit of the landscape including a "river" and "plain". Coupled thermo-hydraulic modeling and simplified conductive heat transfer were considered for a broad range of scenarios. The results showed that when considering the current limited river dimensions and purely conductive heat transfer, taliks are expected to close within a few centuries. However, including coupled advection for flows from the river to the plain (probably pertinent for the eastern Paris Basin aquifer recharge zones) strongly delays talik closure (millennium scale). The impact on regional underground flows is expected to vary from a complete stop of recharge to a reduced recharge, corresponding to the talik zones. Consequences for future modeling approaches of the Paris Basin are discussed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGC11D1028L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGC11D1028L"><span>The Parana paradox: can a model explain the decadal impacts of climate variability and land-cover change?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, E.; Moorcroft, P. R.; Livino, A.; Briscoe, J.</p> <p>2013-12-01</p> <p>Since the 1970s, despite a decrease in rainfall, flow in the Parana river has increased. This paradox is explored using the Ecosystem Demography (ED) model. If there were no change in land cover, the modeled runoff decreased from the 1970s to the 2000s by 11.8% (with 1970 land cover) or 18.8% (with 2008 land cover). When the model is run holding climate constant, the decadal average of the modeled runoff increased by 24.4% (with the 1970s climate) or by 33.6% (with 2000s climate). When the model is run allowing both the actual climate and land-cover changes, the model gives an increase in the decadal average of runoff by 8.5%. This agrees well with 10.5% increase in the actual stream flow as measured at Itaipu. There are three main conclusions from this work. First, the ED model is able to explain a major, paradoxical, reality in the Parana basin. Second, it is necessary to take into account both climate and land use changes when exploring past or future changes in river flows. Third, the ED model, now coupled with a regional climate model (i.e., EDBRAMS), is a sound basis for exploring likely changes in river flows in major South American rivers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1915153W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1915153W"><span>Why Does a Shift in Precipitation from Snow Towards Rain Lead to a Decrease in Long Term Mean River Flow?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woods, Ross</p> <p>2017-04-01</p> <p>Empirical evidence suggests that a shift in precipitation from snow towards rain leads to a strong decrease in long term mean river flow, for a diverse set of snow-dominated catchments across the USA (Berghuijs et al, 2014, Nature Climate Change). Mutually inconsistent hypotheses have been proposed, but no comprehensive explanations are available to explain the observations. Why does less snow apparently lead to less river flow and more evaporation? Is it caused by changes in snow cover, soil freezing, infiltration processes, timing of plant water uptake or something else? Which processes are important where? Solving this scientific puzzle will have significant follow-on impacts for hydrological models, flood risk assessment, seasonal water forecasts, and climate change impacts on water availability, ecosystem functions and other systems impacted by long-term reductions in river flow and evaporation, and their feedbacks to the water cycle. A large international research collaboration (CHIPPER, 34 groups from 14 countries) has formed to make a joint contribution to improved understanding of links between the phase of precipitation and the hydrological cycle, with a particular focus on water balance. This presentation will review progress since 2014 on the topic, outline intended future lines of investigation, and invite feedback and additional collaborations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1713986S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1713986S"><span>The impacts of climate and land-use change scenarios on river ecology: the case of Margaritifera margaritifera</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Santos, Regina; Fernandes, Luís; Varandas, Simone; Pereira, Mário; Sousa, Ronaldo; Teixeira, Amilcar; Lopes-Lima, Manuel; Cortes, Rui; Pacheco, Fernando</p> <p>2015-04-01</p> <p>Climate change is one of the most important causes of biodiversity loss in freshwater ecosystems and it is expected to cause extinctions in many species in the future. Freshwater ecosystems are also highly affected by anthropogenic pressures such as land use/land cover changes, water abstractions and impoundments. The aim of this study is to assess the impacts of future climate and land-use in the Beça River (northern Portugal) namely on the conservation status of the endangered pearl mussel Margaritifera margaritifera (Linnaeus, 1758). This is an environmental indicator and endangered species currently present in several stretches of the Beça River that still hold adequate ecological conditions. However, the species is threatened by the precipitation decrease projected for the 21st century and the deviation of a significant portion of the river water to an adjacent watershed (since 1998). This decrease in river water can be especially acute during the summer months, forming small pools dispersed along the water course where M. margaritifera, and its host (Salmo trutta), barely find biological conditions for survival. The materials and methods used in this study include; (i) the assessment of water quality based on minimum, maximum and average values of relevant physicochemical parameters within the period 2000-2009; (ii) assessment of future climate change settings based on air temperature and precipitation projected by Regional and Global Circulation Models for recent past (1961 - 1990) and future climate scenarios (2071 - 2099); (iii) data processing to remove the model biases; and, (iv) integrated watershed modelling with river-planning (Mike Basin) and broad GIS (ArcMap) computer packages. Our findings comprise: (i); a good relationship between current wildfire incidence and river water quality; (ii) an increase in the future air temperature throughout the year; (iii) increases in future precipitations during winter and decreases during the other seasons; (iv) major runoff decrease more likely to occur between April and June and in October (<-30% in both future scenarios) which may reach -50%; (v) a decrease in the simulated average water depth in most river sections leading to habitat fragmentation by loss of connectivity during the summer season (water depth < 10 cm) with reverberating effects on the mobility of Salmo trutta, which may impair the reproduction and recruitment of pearl mussels. In addition, human-related threats mostly associated with the presence of dams and wildfires are expected to increase in the future. The presence of dams contribute to an additional decrease in the connectivity and river flow while the forest fires are a major threat, related to the wash out of burned areas during storms, eventually causing the disappearance of the mussels, especially the juveniles. In view of future climate and land-use change scenarios, conservation strategies are proposed to maintain good status and enable recovery, including the negotiation of ecological flows with the river board authorities, the replanting of riparian vegetation along the water course and the reintroduction of native tree species throughout the catchment. This work was supported by national funds by FCT - Portuguese Foundation for Science and Technology, under the project PEst-OE/AGR/UI4033/2014 and by the project SUSTAINSYS: Environmental Sustainable Agro-Forestry Systems (NORTE-07-0124-FEDER-000044), financed by the North Portugal Regional Operational Programme (ON.2 - O Novo Norte), under the National Strategic Reference Framework (QREN), through the European Regional Development Fund (FEDER), as well as by National Funds (PIDDAC) through the Portuguese Foundation for Science and Technology (FCT/MEC).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/130650','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/130650"><span>Development of a regional groundwater flow model for the area of the Idaho National Engineering Laboratory, Eastern Snake River Plain Aquifer</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>McCarthy, J.M.; Arnett, R.C.; Neupauer, R.M.</p> <p></p> <p>This report documents a study conducted to develop a regional groundwater flow model for the Eastern Snake River Plain Aquifer in the area of the Idaho National Engineering Laboratory. The model was developed to support Waste Area Group 10, Operable Unit 10-04 groundwater flow and transport studies. The products of this study are this report and a set of computational tools designed to numerically model the regional groundwater flow in the Eastern Snake River Plain aquifer. The objective of developing the current model was to create a tool for defining the regional groundwater flow at the INEL. The model wasmore » developed to (a) support future transport modeling for WAG 10-04 by providing the regional groundwater flow information needed for the WAG 10-04 risk assessment, (b) define the regional groundwater flow setting for modeling groundwater contaminant transport at the scale of the individual WAGs, (c) provide a tool for improving the understanding of the groundwater flow system below the INEL, and (d) consolidate the existing regional groundwater modeling information into one usable model. The current model is appropriate for defining the regional flow setting for flow submodels as well as hypothesis testing to better understand the regional groundwater flow in the area of the INEL. The scale of the submodels must be chosen based on accuracy required for the study.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1996/4014/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1996/4014/report.pdf"><span>Determination of the 100-year flood plain on Upper Three Runs and selected tributaries, and the Savannah River at the Savannah River site, South Carolina, 1995</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lanier, T.H.</p> <p>1996-01-01</p> <p>The 100-year flood plain was determined for Upper Three Runs, its tributaries, and the part of the Savannah River that borders the Savannah River Site. The results are provided in tabular and graphical formats. The 100-year flood-plain maps and flood profiles provide water-resource managers of the Savannah River Site with a technical basis for making flood-plain management decisions that could minimize future flood problems and provide a basis for designing and constructing drainage structures along roadways. A hydrologic analysis was made to estimate the 100-year recurrence- interval flow for Upper Three Runs and its tributaries. The analysis showed that the well-drained, sandy soils in the head waters of Upper Three Runs reduce the high flows in the stream; therefore, the South Carolina upper Coastal Plain regional-rural-regression equation does not apply for Upper Three Runs. Conse- quently, a relation was established for 100-year recurrence-interval flow and drainage area using streamflow data from U.S. Geological Survey gaging stations on Upper Three Runs. This relation was used to compute 100-year recurrence-interval flows at selected points along the stream. The regional regression equations were applicable for the tributaries to Upper Three Runs, because the soil types in the drainage basins of the tributaries resemble those normally occurring in upper Coastal Plain basins. This was verified by analysis of the flood-frequency data collected from U.S. Geological Survey gaging station 02197342 on Fourmile Branch. Cross sections were surveyed throughout each reach, and other pertinent data such as flow resistance and land-use were col- lected. The surveyed cross sections and computed 100-year recurrence-interval flows were used in a step-backwater model to compute the 100-year flood profile for Upper Three Runs and its tributaries. The profiles were used to delineate the 100-year flood plain on topographic maps. The Savannah River forms the southwestern border of the Savannah River Site. Data from previously published reports were used to delineate the 100-year flood plain for the Savannah River from the downstream site boundary at the mouth of Lower Three Runs at river mile 125 to the upstream site boundary at river mile 163.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2014/5221/pdf/sir2014-5221.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2014/5221/pdf/sir2014-5221.pdf"><span>Hydrogeologic framework and groundwater/surface-water interactions of the South Fork Nooksack River Basin, northwestern Washington</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Gendaszek, Andrew S.</p> <p>2014-01-01</p> <p>A hydrogeologic framework of the South Fork (SF) Nooksack River Basin in northwestern Washington was developed and hydrologic data were collected to characterize the groundwater-flow system and its interaction with surface‑water features. In addition to domestic, agricultural, and commercial uses of groundwater within the SF Nooksack River Basin, groundwater has the potential to provide ecological benefits by maintaining late-summer streamflows and buffering stream temperatures. Cold-water refugia, created and maintained in part by groundwater, have been identified by water-resource managers as key elements to restore the health and viability of threatened salmonids in the SF Nooksack River. The SF Nooksack River drains a 183-square mile area of the North Cascades and the Puget Lowland underlain by unconsolidated glacial and alluvial sediments deposited over older sedimentary, metamorphic, and igneous bedrock. The primary aquifer that interacts with the SF Nooksack River was mapped within unconsolidated glacial outwash and alluvial sediment. The lower extent of this unit is bounded by bedrock and fine-grained, poorly sorted unconsolidated glaciomarine and glaciolacustrine sediments. In places, these deposits overlie and confine an aquifer within older glacial sediments. The extent and thickness of the hydrogeologic units were assembled from mapped geologic units and lithostratigraphic logs of field-inventoried wells. Generalized groundwater-flow directions within the surficial aquifer were interpreted from groundwater levels measured in August 2012; and groundwater seepage gains and losses to the SF Nooksack River were calculated from synoptic streamflow measurements made in the SF Nooksack River and its tributaries in September 2012. A subset of the field-inventoried wells was measured at a monthly interval to determine seasonal fluctuations in groundwater levels during water year 2013. Taken together, these data provide the foundation for a future groundwater-flow model of the SF Nooksack River Basin that may be used to investigate the potential effects of future climate change, land use, and groundwater pumping on water resources in the study area. Site-specific hydrologic data, including time series of longitudinal temperature profiles measured with a fiber-optic distributed temperature sensor and continuous monitoring of stream stage and water levels measured in wells in adjacent wetlands and aquifers, also were measured to characterize the interaction among the SF Nooksack River, surficial aquifers, and riparian wetlands.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27482082','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27482082"><span>Contrasting climate change impact on river flows from high-altitude catchments in the Himalayan and Andes Mountains.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ragettli, Silvan; Immerzeel, Walter W; Pellicciotti, Francesca</p> <p>2016-08-16</p> <p>Mountain ranges are the world's natural water towers and provide water resources for millions of people. However, their hydrological balance and possible future changes in river flow remain poorly understood because of high meteorological variability, physical inaccessibility, and the complex interplay between climate, cryosphere, and hydrological processes. Here, we use a state-of-the art glacio-hydrological model informed by data from high-altitude observations and the latest climate change scenarios to quantify the climate change impact on water resources of two contrasting catchments vulnerable to changes in the cryosphere. The two study catchments are located in the Central Andes of Chile and in the Nepalese Himalaya in close vicinity of densely populated areas. Although both sites reveal a strong decrease in glacier area, they show a remarkably different hydrological response to projected climate change. In the Juncal catchment in Chile, runoff is likely to sharply decrease in the future and the runoff seasonality is sensitive to projected climatic changes. In the Langtang catchment in Nepal, future water availability is on the rise for decades to come with limited shifts between seasons. Owing to the high spatiotemporal resolution of the simulations and process complexity included in the modeling, the response times and the mechanisms underlying the variations in glacier area and river flow can be well constrained. The projections indicate that climate change adaptation in Central Chile should focus on dealing with a reduction in water availability, whereas in Nepal preparedness for flood extremes should be the policy priority.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70189930','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70189930"><span>Predicting regime shifts in flow of the Colorado River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Gangopadhyay, Subhrendu; McCabe, Gregory J.</p> <p>2010-01-01</p> <p>The effects of continued global warming on water resources are a concern for water managers and stake holders. In the western United States, where the combined climatic demand and consumptive use of water is equal to or greater than the natural supply of water for some locations, there is growing concern regarding the sustainability of future water supplies. In addition to the adverse effects of warming on water supply, another issue for water managers is accounting for, and managing, the effects of natural climatic variability, particularly persistently dry and wet periods. Analyses of paleo-reconstructions of Upper Colorado River basin (UCRB) flow demonstrate that severe sustained droughts, and persistent pluvial periods, are a recurring characteristic of hydroclimate in the Colorado River basin. Shifts between persistently dry and wet regimes (e.g., decadal to multi-decadal variability (D2M)) have important implications for water supply and water management. In this study paleo-reconstructions of UCRB flow are used to compute the risks of shifts between persistently wet and dry regimes given the length of time in a specific regime. Results indicate that low frequency variability of hydro-climatic conditions and the statistics that describe this low frequency variability can be useful to water managers by providing information about the risk of shifting from one hydrologic regime to another. To manage water resources in the future water managers will have to understand the joint hydrologic effects of natural climate variability and global warming. These joint effects may produce future hydrologic conditions that are unprecedented in both the instrumental and paleoclimatic records.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4995932','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4995932"><span>Contrasting climate change impact on river flows from high-altitude catchments in the Himalayan and Andes Mountains</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Pellicciotti, Francesca</p> <p>2016-01-01</p> <p>Mountain ranges are the world’s natural water towers and provide water resources for millions of people. However, their hydrological balance and possible future changes in river flow remain poorly understood because of high meteorological variability, physical inaccessibility, and the complex interplay between climate, cryosphere, and hydrological processes. Here, we use a state-of-the art glacio-hydrological model informed by data from high-altitude observations and the latest climate change scenarios to quantify the climate change impact on water resources of two contrasting catchments vulnerable to changes in the cryosphere. The two study catchments are located in the Central Andes of Chile and in the Nepalese Himalaya in close vicinity of densely populated areas. Although both sites reveal a strong decrease in glacier area, they show a remarkably different hydrological response to projected climate change. In the Juncal catchment in Chile, runoff is likely to sharply decrease in the future and the runoff seasonality is sensitive to projected climatic changes. In the Langtang catchment in Nepal, future water availability is on the rise for decades to come with limited shifts between seasons. Owing to the high spatiotemporal resolution of the simulations and process complexity included in the modeling, the response times and the mechanisms underlying the variations in glacier area and river flow can be well constrained. The projections indicate that climate change adaptation in Central Chile should focus on dealing with a reduction in water availability, whereas in Nepal preparedness for flood extremes should be the policy priority. PMID:27482082</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.usgs.gov/of/2016/1186/ofr20161186.pdf','USGSPUBS'); return false;" href="http://pubs.usgs.gov/of/2016/1186/ofr20161186.pdf"><span>Summary of environmental flow monitoring for the Sustainable Rivers Project on the Middle Fork Willamette and McKenzie Rivers, western Oregon, 2014–15</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jones, Krista L.; Mangano, Joseph F.; Wallick, J. Rose; Bervid, Heather D.; Olson, Melissa; Keith, Mackenzie K.; Bach, Leslie</p> <p>2016-11-07</p> <p>This report presents the results of an ongoing environmental flow monitoring study by The Nature Conservancy (TNC), U.S. Army Corps of Engineers (USACE), and U.S. Geological Survey in support of the Sustainable Rivers Project (SRP) of TNC and USACE. The overarching goal of this study is to evaluate and characterize relations between streamflow, geomorphic processes, and black cottonwood (Populus trichocarpa) recruitment on the Middle Fork Willamette and McKenzie Rivers, western Oregon, that were hypothesized in earlier investigations. The SRP can use this information to plan future monitoring and scientific investigations, and to help mitigate the effects of dam operations on streamflow regimes, geomorphic processes, and biological communities, such as black cottonwood forests, in consultation with regional experts. The four tasks of this study were to:Compare the hydrograph from Water Year (WY) 2015 with hydrographs from WYs 2000–14 and the SRP flow recommendations,Assess short-term and system-wide changes in channel features and vegetation throughout the alluvial valley section of the Middle Fork Willamette River (2005–12),Examine changes in channel features and vegetation over two decades (1994–2014) for two short mapping zones on the Middle Fork Willamette and McKenzie Rivers, andComplete a field investigation of summer stage and the growth of black cottonwood and other vegetation on the Middle Fork Willamette and McKenzie Rivers in summer 2015.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H13C1224G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H13C1224G"><span>Assessing the Impact of Climate Change on Stream Temperatures in the Methow River Basin, Washington</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gangopadhyay, S.; Caldwell, R. J.; Lai, Y.; Bountry, J.</p> <p>2011-12-01</p> <p>The Methow River in Washington offers prime spawning habitat for salmon and other cold-water fishes. During the summer months, low streamflows on the Methow result in cutoff side channels that limit the habitat available to these fishes. Future climate scenarios of increasing air temperature and decreasing precipitation suggest the potential for increasing loss of habitat and fish mortality as stream temperatures rise in response to lower flows and additional heating. To assess the impacts of climate change on stream temperature in the Methow River, the US Bureau of Reclamation is developing an hourly time-step, two-dimensional hydraulic model of the confluence of the Methow and Chewuch Rivers above Winthrop. The model will be coupled with a physical stream temperature model to generate spatial representations of stream conditions conducive for fish habitat. In this study, we develop a statistical framework for generating stream temperature time series from global climate model (GCM) and hydrologic model outputs. Regional observations of stream temperature and hydrometeorological conditions are used to develop statistical models of daily mean stream temperature for the Methow River at Winthrop, WA. Temperature and precipitation projections from 10 global climate models (GCMs) are coupled with the streamflow generated using the University of Washington Variable Infiltration Capacity model. The projections serve as input to the statistical models to generate daily time series of mean daily stream temperature. Since the output from the GCM, VIC, and statistical models offer only daily data, a k-nearest neighbor (k-nn) resampling technique is employed to select appropriate proportion vectors for disaggregating the Winthrop daily flow and temperature to an upstream location on each of the rivers above the confluence. Hourly proportion vectors are then used to disaggregate the daily flow and temperature to hourly values to be used in the hydraulic model. Historical meteorological variables are also selected using the k-nn method. We present the statistical modeling framework using Generalized Linear Models (GLMs), along with diagnostics and measurements of skill. We will also provide a comparison of the stream temperature projections from the future years of 2020, 2040, and 2080 and discuss the potential implications on fish habitat in the Methow River. Future integration of the hourly climate scenarios in the hydraulic model will provide the ability to assess the spatial extent of habitat impacts and allow the USBR to evaluate the effectiveness of various river restoration projects in maintaining or improving habitat in a changing climate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014HESSD..11.4925R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014HESSD..11.4925R"><span>Climate change and wetland loss impacts on a Western river's water quality</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Records, R. M.; Arabi, M.; Fassnacht, S. R.; Duffy, W. G.; Ahmadi, M.; Hegewisch, K. C.</p> <p>2014-05-01</p> <p>An understanding of potential stream water quality conditions under future climate is critical for the sustainability of ecosystems and protection of human health. Changes in wetland water balance under projected climate could alter wetland extent or cause wetland loss. This study assessed the potential climate-induced changes to in-stream sediment and nutrients loads in the historically snow melt-dominated Sprague River, Oregon, Western United States. Additionally, potential water quality impacts of combined changes in wetland water balance and wetland area under future climatic conditions were evaluated. The study utilized the Soil and Water Assessment Tool (SWAT) forced with statistical downscaling of general circulation model (GCM) data from the Coupled Model Intercomparison Project 5 (CMIP5) using the Multivariate Adaptive Constructed Analogs (MACA) method. Our findings suggest that in the Sprague River (1) mid-21st century nutrient and sediment loads could increase significantly during the high flow season under warmer-wetter climate projections, or could change only nominally in a warmer and somewhat drier future; (2) although water quality conditions under some future climate scenarios and no wetland loss may be similar to the past, the combined impact of climate change and wetland losses on nutrient loads could be large; (3) increases in stream total phosphorus (TP) concentration with wetland loss under future climate scenarios would be greatest at high-magnitude, low-probability flows; and (4) loss of riparian wetlands in both headwaters and lowlands could increase outlet TP loads to a similar degree, but this could be due to distinctly different mechanisms in different parts of the watershed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2678624','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2678624"><span>Sustainable water deliveries from the Colorado River in a changing climate</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Barnett, Tim P.; Pierce, David W.</p> <p>2009-01-01</p> <p>The Colorado River supplies water to 27 million users in 7 states and 2 countries and irrigates over 3 million acres of farmland. Global climate models almost unanimously project that human-induced climate change will reduce runoff in this region by 10–30%. This work explores whether currently scheduled future water deliveries from the Colorado River system are sustainable under different climate-change scenarios. If climate change reduces runoff by 10%, scheduled deliveries will be missed ≈58% of the time by 2050. If runoff reduces 20%, they will be missed ≈88% of the time. The mean shortfall when full deliveries cannot be met increases from ≈0.5–0.7 billion cubic meters per year (bcm/yr) in 2025 to ≈1.2–1.9 bcm/yr by 2050 out of a request of ≈17.3 bcm/yr. Such values are small enough to be manageable. The chance of a year with deliveries <14.5 bcm/yr increases to 21% by midcentury if runoff reduces 20%, but such low deliveries could be largely avoided by reducing scheduled deliveries. These results are computed by using estimates of Colorado River flow from the 20th century, which was unusually wet; if the river reverts to its long-term mean, shortfalls increase another 1–1.5 bcm/yr. With either climate-change or long-term mean flows, currently scheduled future water deliveries from the Colorado River are not sustainable. However, the ability of the system to mitigate droughts can be maintained if the various users of the river find a way to reduce average deliveries. PMID:19380718</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22888030','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22888030"><span>Accumulated state assessment of the Peace-Athabasca-Slave River system.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dubé, Monique G; Wilson, Julie E</p> <p>2013-07-01</p> <p>Effects-based analysis is a fundamental component of watershed cumulative effects assessment. This study conducted an effects-based analysis for the Peace-Athabasca-Slave River System, part of the massive Mackenzie River Basin, encompassing 20% of Canada's total land mass and influenced by cumulative contributions of the W.A.C. Bennett Dam (Peace River) and industrial activities including oil sands mining (Athabasca River). This study assessed seasonal changes in 1) Peace River water quality and quantity before and after dam development, 2) Athabasca River water quality and quantity before and after oil sands developments, 3) tributary inputs from the Peace and Athabasca Rivers to the Slave River, and 4) upstream to downstream differences in water quality in the Slave River. In addition, seasonal benchmarks were calculated for each river based on pre-perturbation post-perturbation data for future cumulative effects assessments. Winter discharge (January-March) from the Peace and Slave Rivers was significantly higher than before dam construction (pre-1967) (p < 0.05), whereas summer peak flows (May-July) were significantly lower than before the dam showing that regulation has significantly altered seasonal flow regimes. During spring freshet and summer high flows, the Peace River strongly influenced the quality of the Slave River, as there were no significant differences in loadings of dissolved N, total P (TP), total organic C (TOC), total As, total Mn, total V, and turbidity and specific conductance between these rivers. In the Athabasca River, TP and specific conductance concentrations increased significantly since before oil sands developments (1967-2010), whereas dissolved N and sulfate have increased after the oil sands developments (1977-2010). Recently, the Athabasca River had significantly higher concentrations of dissolved N, TP, TOC, dissolved sulfate, specific conductance, and total Mn than either the Slave or the Peace Rivers during the winter months. The transboundary nature of the Peace, Athabasca, and Slave River basins has resulted in fragmented monitoring and reporting of the state of these rivers, and a more consistent monitoring framework is recommended. Copyright © 2012 SETAC.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015BGD....1212321F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015BGD....1212321F"><span>Optical properties and bioavailability of dissolved organic matter along a flow-path continuum from soil pore waters to the Kolyma River, Siberia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frey, K. E.; Sobczak, W. V.; Mann, P. J.; Holmes, R. M.</p> <p>2015-08-01</p> <p>The Kolyma River in Northeast Siberia is among the six largest arctic rivers and drains a region underlain by vast deposits of Holocene-aged peat and Pleistocene-aged loess known as yedoma, most of which is currently stored in ice-rich permafrost throughout the region. These peat and yedoma deposits are important sources of dissolved organic matter (DOM) to inland waters that in turn play a significant role in the transport and ultimate remineralization of organic carbon to CO2 and CH4 along the terrestrial flow-path continuum. The turnover and fate of terrigenous DOM during offshore transport will largely depend upon the composition and amount of carbon released to inland and coastal waters. Here, we measured the optical properties of chromophoric DOM (CDOM) from a geographically extensive collection of waters spanning soil pore waters, streams, rivers, and the Kolyma River mainstem throughout a ∼ 250 km transect of the northern Kolyma River basin. During the period of study, CDOM absorbance values were found to be robust proxies for the concentration of DOM, whereas additional CDOM parameters such as spectral slopes (S) were found to be useful indicators of DOM quality along the flow-path. In particular, CDOM absorption at 254 nm showed a strong relationship with dissolved organic carbon (DOC) concentrations across all water types (r2 = 0.958, p < 0.01). The spectral slope ratio (SR) of CDOM demonstrated statistically significant differences between all four water types and tracked changes in the concentration of bioavailable DOC, suggesting that this parameter may be suitable for clearly discriminating shifts in organic matter characteristics among water types along the full flow-path continuum across this landscape. The heterogeneity of environmental characteristics and extensive continuous permafrost of the Kolyma River basin combine to make this a critical region to investigate and monitor. With ongoing and future permafrost degradation, peat and yedoma deposits throughout the Northeast Siberian region will become more hydrologically active, providing greater amounts of DOM to fluvial networks and ultimately to the Arctic Ocean. The ability to rapidly and comprehensively monitor shifts in the quantity and quality of DOM across the landscape is therefore critical for understanding potential future feedbacks on the arctic carbon cycle.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70168634','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70168634"><span>Increasing influence of air temperature on upper Colorado River streamflow</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Woodhouse, Connie A.; Pederson, Gregory T.; Morino, Kiyomi; McAfee, Stephanie A.; McCabe, Gregory J.</p> <p>2016-01-01</p> <p>This empirical study examines the influence of precipitation, temperature, and antecedent soil moisture on upper Colorado River basin (UCRB) water year streamflow over the past century. While cool season precipitation explains most of the variability in annual flows, temperature appears to be highly influential under certain conditions, with the role of antecedent fall soil moisture less clear. In both wet and dry years, when flow is substantially different than expected given precipitation, these factors can modulate the dominant precipitation influence on streamflow. Different combinations of temperature, precipitation, and soil moisture can result in flow deficits of similar magnitude, but recent droughts have been amplified by warmer temperatures that exacerbate the effects of relatively modest precipitation deficits. Since 1988, a marked increase in the frequency of warm years with lower flows than expected, given precipitation, suggests continued warming temperatures will be an increasingly important influence in reducing future UCRB water supplies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MsT.........45S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MsT.........45S"><span>Assessing the influence of climate change on flooding hazards following tropical cyclone events in the Southeast United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stone, Monica Helen</p> <p></p> <p>Recent tropical cyclones, like Hurricane Katrina, have been some of the worst the United States has experienced. Tropical cyclones are expected to intensify, bringing about 20% more precipitation, in the near future in response to global climate warming. Further, global climate warming may extend the hurricane season. This study focuses on four major river basins (Neches, Pearl, Mobile, and Roanoke) in the Southeast United States that are frequently impacted by tropical cyclones. The Soil and Water Assessment Tool (SWAT) was used to model flow along these rivers from 1998-2014 with 20% more precipitation during tropical cyclones. The results of this study show that an increase in tropical cyclone precipitation due to future climate change may increase peak flows at the mouths of these Southeast rivers by ˜7-18%. Most tropical cyclones that impact these river basins occur during the low discharge season, and thus rarely produce flooding conditions at their mouths. An extension of the current hurricane season of June-November, due to global climate warming, could encroach upon the wet season in these basins and lead to increased flooding. On average, this analysis shows that an extension of the hurricane season to May-December increased flooding susceptibility by 63% for the rivers analyzed in this study. That is, 4-6 more days per year likely would have been above bankfull discharge if an average tropical cyclone had occurred any day (based on 1998-2014 data) in the months May-December than in the current hurricane season months of June-November. More research is needed on the mechanisms and processes involved in the water balance of the four rivers analyzed in this study, and others in the Southeast United States, and how this is likely to change in the near future with global climate warming.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H31H1306P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H31H1306P"><span>Managing Environmental Flows for Impounded Rivers in Semi-Arid Regions- A Habitat Suitability Index (HSI) Approach for the Assessment of River Habitat for Salmonid Populations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pai, H.; Sivakumaran, K.; Villamizar, S. R.; Flanagan, J.; Guo, Q.; Harmon, T. C.</p> <p>2013-12-01</p> <p>Balancing ecosystem health in water-scarce, agriculturally dominated river basins remains a challenge. In dry water years, maintaining conditions for restored and sustained indigenous fish populations (a frequently used indicator for ecosystem health) is particularly challenging. Competing human demands include urban and agricultural water supplies, hydropower, and flood control. In many semi-arid regions, increasing drought intensity and frequency under future climate scenarios will combine with population increases to water scarcity. The goal of this work is to better understand how reservoir releases affect fish habitat and overall river aquatic ecosystem quality. Models integrating a diverse array of physical and biological processes and system state are used to forecast the river ecosystem response to changing drivers. We propose a distributed parameter-based Habitat Suitability Index (HSI) approach for assessing fish habitat quality. Our river ecosystem HSI maps are based on a combination of the following: (1) In situ data describing stream flow and water quality conditions; (2) Spatial observations, including surveyed cross-sections, aerial imagery and digital elevation maps (DEM) of the river and its riparian corridor; and (3) Simulated spatially distributed water depths, flow velocities, and temperatures estimated from 1D and 2D river flow and temperature models (HEC-RAS and CE-QUAL-W2, respectively). With respect to (2), image processing schemes are used to classify and map key habitat features, namely riparian edge and shallow underwater vegetation. HSI maps can be modified temporally to address specific life cycle requirements of indicator fish species. Results are presented for several reaches associated with the San Joaquin River Restoration Project, focusing on several components of the Chinook salmon life cycle. HSI maps and interpretations are presented in the context of a range of prescribed reservoir release hydrographs linked to California water year descriptors (wet, dry, critical low, etc.). Implications are discussed with respect to effective reservoir operation (requisite flow releases and temperature) and restorative actions (e.g., riparian vegetation) in the context of habitat suitability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMEP21A0666S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMEP21A0666S"><span>Assessing overland sediment transport to the Apalachicola River/Bay in Florida</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smar, D. E.; Hagen, S.; Daranpob, A.; Passeri, D.</p> <p>2011-12-01</p> <p>An ongoing study in Franklin County, Florida is focused on classifying the mechanisms of sediment transport from the overland areas to eventual deposition in the Apalachicola River and surrounding estuaries. Sediment cores and water column samples were collected at various locations along the Apalachicola River, its tributaries, and distributaries over a two-week period during the wet season. A preliminary particle size distribution analysis of the sediment cores and water column samples demonstrates decreasing particle sizes as the river and wetlands progress toward the ocean. Daily water samples from the mouth of the Apalachicola River and two distributaries reveal fluctuating total suspended solid (TSS) concentrations. To understand these deviations, flow rate and water level at each location is inspected. Because the nearest USGS gage is approximately 16 miles upstream from these sites, investigation of the hydrodynamic influences of sediment transport is conducted by developing a hydrodynamic model simulating river flow and tides in the Apalachicola River and bay system. With spatially accurate flow rates and water levels, an attempt can be made to correlate flow rate with fluctuating TSS concentrations. Precipitation events during the sampling period also support spikes in the TSS concentrations as expected. Assessing sediment transport to the river/bay system will lead to a better understanding of the regression or accretion of the river's alluvial fan and the marsh platform. High flow periods following extreme rain events (which are expected to intensify under global climate change) transport more sediment downstream, however, the interaction with tidal and sea level effects are still being analyzed. With rising sea levels, it is expected that the alluvial fan will recede and wetland areas may migrate inland gradually transforming existing dry lands such as pine forests into new wetland regions. Future work will include an analysis of the tidal cycle during the sampling period to more accurately classify fluctuation of TSS concentration in the downstream samples. The data collection process and laboratory analysis will also be repeated in the dry season, and subsequent years to observe temporal trends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H31E1551Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H31E1551Z"><span>How to allocate water resources under climate change in the arid endorheic river basin, Northwest China</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, A.; Feng, D.; Tian, Y.; Zheng, Y.</p> <p>2017-12-01</p> <p>Water resource is of fundamental importance to the society and ecosystem in arid endorheic river basins, and water-use conflicts between upstream and downstream are usually significant. Heihe river basin (HRB) is the second largest endorheic river basin in china, which is featured with dry climate, intensively irrigated farmlands in oases and significant surface water-groundwater interaction. The irrigation districts in the middle HRB consume a large portion of the river flow, and the low HRB, mainly Gobi Desert, has an extremely vulnerable ecological environment. The water resources management has significantly altered the hydrological processes in HRB, and is now facing multiple challenges, including decline of groundwater table in the middle HRB, insufficient environmental flow for the lower HRB. Furthermore, future climate change adds substantial uncertainty to the water system. Thus, it is imperative to have a sustainable water resources management in HRB in order to tackle the existing challenges and future uncertainty. Climate projection form a dynamical downscaled climate change scenario shows precipitation will increase at a rate of approximately 3 millimeter per ten years and temperature will increase at a rate of approximately 0.2 centigrade degree per ten years in the following 50 years in the HRB. Based on an integrated ecohydrological model, we evaluated how the climate change and agricultural development would collaboratively impact the water resources and ecological health in the middle and lower HRB, and investigated how the water management should cope with the complex impact.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29859438','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29859438"><span>Engineered river flow-through to improve mine pit lake and river values.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McCullough, Cherie D; Schultze, Martin</p> <p>2018-05-30</p> <p>Mine pit lakes may develop at mine closure when mining voids extend below groundwater levels and fill with water. Acid and metalliferous drainage (AMD) and salinity are common problems for pit lake water quality. Contaminated pit lake waters can directly present significant risk to both surrounding and regional communities and natural environmental values and limit beneficial end use opportunities. Pit lake waters can also discharge into surface and groundwater; or directly present risks to wildlife, stock and human end users. Riverine flow-through is increasingly proposed to mitigate or remediate pit lake water contamination using catchment scale processes. This paper presents the motivation and key processes and considerations for a flow-through pit lake closure strategy. International case studies as precedent and lessons for future application are described from pit lakes that use or propose flow-through as a key component of their mine closure design. Chemical and biological processes including dilution, absorption and flocculation and sedimentation can sustainably reduce pit lake contaminant concentrations to acceptable levels for risk and enable end use opportunities to be realised. Flow-through may be a valid mine closure strategy for pit lakes with poor water quality. However, maintenance of existing riverine system values must be foremost. We further suggest that decant river water quality may, in some circumstances, be improved; notably in examples of meso-eutrophic river waters flowing through slightly acidic pit lakes. Flow-through closure strategies must be scientifically justifiable and risk-based for both lake and receptors potentially affected by surface and groundwater transport. Due to the high-uncertainty associated with this complex strategy, biotic and physico-chemical attributes of both inflow and decant river reaches as well as lake should be well monitored. Monitoring should directly feed into an adaptive management framework discussed with key stakeholders with validation of flow-through as a sustainable strategy prior to mine relinquishment. Copyright © 2018 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMEP51A0853S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMEP51A0853S"><span>Modelling of bio-morphodynamics in braided rivers: applications to the Waitaki river (New Zealand)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stecca, G.; Zolezzi, G.; Hicks, M.; Measures, R.; Bertoldi, W.</p> <p>2016-12-01</p> <p>The planform shape of rivers results from the complex interaction between flow, sediment transport and vegetation processes, and can evolve in time following a change in these controls. The braided planform of the lower Waitaki (New Zealand), for instance, is endangered by the action of artificially-introduced alien vegetation, which spread after the reduction in magnitude of floods following hydropower dam construction. These processes, by favouring the flow concentration into the main channel, would likely promote a shift towards single thread morphology if vegetation was not artificially removed within a central fairway. The purpose of this work is to address the future evolution of these river systems under different management scenarios through two-dimensional numerical modelling. The construction of a suitable model represents a task in itself, since a modelling framework coupling all the relevant processes is not straightforwardly available at present. Our starting point is the GIAMT2D numerical model, solving two-dimensional flow and bedload transport in wet/dry domains, and recently modified by the inclusion of a rule-based bank erosion model. We further develop this model by adding a vegetation module, which accounts in a simplified manner for time-evolving biomass density, and tweaks the local flow roughness, critical shear stress for sediment transport and bank erodibility accordingly. We plan to apply the model to address the decadal-scale evolution of one reach in the Waitaki river, comparing different management scenarios for vegetation control.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JHyd..559..787L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JHyd..559..787L"><span>Spatio-temporal variational characteristics analysis of heavy metals pollution in water of the typical northern rivers, China</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, Hongwei; Yu, Sen</p> <p>2018-04-01</p> <p>The rapid urbanization and industrialization in developing countries have increased pollution by heavy metals, which is a concern for human health and the environment. In this study, according to the data obtained from the monitoring stations in the Songhua River basin, the multivariate statistical analysis methods are applied to the hydrological data of the Songhua River basin in order to examine the relation between human activities and the spatio-temporal change of heavy metals (Pb and Cu) in water. By comparing the concentrations at different flow periods, the minimum Pb concentrations are found to have occurred most frequently in low flow periods while the maximum values mostly appeared in average flow periods. Moreover, the minimum Cu concentration in the water frequently occurred in high flow periods. The results show there are low Pb and Cu concentrations in upstream and downstream sections and high concentrations in mid-stream sections, and high concentrations are most frequently measured in the sections of Ashihe' downstream and estuary. Moreover, we have predicted the future (during 2018-2025) trend of the change for the heavy metals pollution in the rivers. The results demonstrated intense human activities are the most important factor causing jump features of typical heavy metal pollution in the different periods for different sections of this study area. The research would provide decision-making and planning for the Songhua River basin during the period of China's 13th Five-Year Plan.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25602549','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25602549"><span>Effect of climate change on environmental flow indicators in the narew basin, poland.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Piniewski, Mikołaj; Laizé, Cédric L R; Acreman, Michael C; Okruszko, Tomasz; Schneider, Christof</p> <p>2014-01-01</p> <p>Environmental flows-the quantity of water required to maintain a river ecosystem in its desired state-are of particular importance in areas of high natural value. Water-dependent ecosystems are exposed to the risk of climate change through altered precipitation and evaporation. Rivers in the Narew basin in northeastern Poland are known for their valuable river and wetland ecosystems, many of them in pristine or near-pristine condition. The objective of this study was to assess changes in the environmental flow regime of the Narew river system, caused by climate change, as simulated by hydrological models with different degrees of physical characterization and spatial aggregation. Two models were assessed: the river basin scale model Soil and Water Assessment Tool (SWAT) and the continental model of water availability and use WaterGAP. Future climate change scenarios were provided by two general circulation models coupled with the A2 emission scenario: IPSL-CM4 and MIROC3.2. To assess the impact of climate change on environmental flows, a method based conceptually on the "range of variability" approach was used. The results indicate that the environmental flow regime in the Narew basin is subject to climate change risk, whose magnitude and spatial variability varies with climate model and hydrological modeling scale. Most of the analyzed sites experienced moderate impacts for the Generic Environmental Flow Indicator (GEFI), the Floodplain Inundation Indicator, and the River Habitat Availability Indicator. The consistency between SWAT and WaterGAP for GEFI was medium: in 55 to 66% of analyzed sites, the models suggested the same level of impact. Hence, we suggest that state-of-the-art, high-resolution, global- or continental-scale models, such as WaterGAP, could be useful tools for water management decision-makers and wetland conservation practitioners, whereas models such as SWAT should serve as a complementary tool for more specific, smaller-scale, local assessments. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002IJCli..22..219W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002IJCli..22..219W"><span>Prospects for seasonal forecasting of summer drought and low river flow anomalies in England and Wales</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wedgbrow, C. S.; Wilby, R. L.; Fox, H. R.; O'Hare, G.</p> <p>2002-02-01</p> <p>Future climate change scenarios suggest enhanced temporal and spatial gradients in water resources across the UK. Provision of seasonal forecast statistics for surface climate variables could alleviate some negative effects of climate change on water resource infrastructure. This paper presents a preliminary investigation of spatial and temporal relationships between large-scale North Atlantic climatic indices, drought severity and river flow anomalies in England and Wales. Potentially useful predictive relationships are explored between winter indices of the Polar-Eurasian (POL) teleconnection pattern, the North Atlantic oscillation (NAO), North Atlantic sea surface temperature anomalies (SSTAs), and the summer Palmer drought severity index (PDSI) and reconstructed river flows in England and Wales. Correlation analyses, coherence testing and an index of forecast potential, demonstrate that preceding winter values of the POL index, SSTA (and to a lesser extent the NAO), provide indications of summer and early autumn drought severity and river flow anomalies in parts of northwest, southwest and southeast England. Correlation analyses demonstrate that positive winter anomalies of T1, POL index and NAO index are associated with negative PDSI (i.e. drought) across eastern parts of the British Isles in summer (r < 0.51). Coherence tests show that a positive winter SSTA (1871-1995) and POL index (1950-95) have preceded below-average summer river flows in the northwest and southwest of England and Wales in 70 to 100% of summers. The same rivers have also experienced below-average flows during autumn following negative winter phases of the NAO index in 64 to 93% of summers (1865-1995). Possible explanations for the predictor-predictand relationships are considered, including the memory of groundwater, and ocean-atmosphere coupling, and regional manifestations of synoptic rainfall processes. However, further research is necessary to increase the number of years and predictor variables from which it is possible to derive rules that may be useful for forecasting.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.H52B..03D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.H52B..03D"><span>Predicting the impacts of existing, pending, and future surface water rights on environmental flows to maintain anadromous salmonids in the northern California wine country</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deitch, M.; Kondolf, G. M.; Merenlender, A.; Cover, M. R.</p> <p>2006-12-01</p> <p>We used digitized aerial photographs on a geographical information system, historical stream flow records, and water rights records to model the effects of existing, pending, and future small reservoirs on stream flow on six tributaries to the Russian River in Sonoma County. Institutions governing whether these reservoirs can operate as constructed, and as proposed, has important implications for efforts to meet human and ecological water needs in the California wine country. Beginning in 1992, state agencies rewrote the policies governing how wine grape growers meet water needs to offer protections to endangered species and public trust values. These changes caused a shift in water management institutions: wine grape growers could no longer rely on surface water appropriations to meet growing water needs for new vineyards, and instead turned to other types of water rights that placed different (and potentially more severe) pressures on aquatic ecosystems. Despite growing controversy over the ecological impacts of existing and pending surface water appropriations (primarily small onstream and offstream reservoirs) on environmental flows necessary to support endangered anadromous salmonids, no analysis has been conducted to evaluate the impacts of existing small reservoirs, pending proposed reservoirs, or future reservoirs on local or catchment-scale stream flow. Our stream flow models indicated that existing and pending small reservoirs can eliminate flow immediately downstream of small reservoirs at the onset of the rainy season (when adult salmonids begin to migrate upstream to spawn); but the cumulative effect of several small reservoirs on stream reaches suitable for spawning is dampened by the spatial distribution of small reservoirs in a drainage network. The temporal extant of local flow effects is variable; most recent and pending onstream reservoirs can impair flows late into the rainy season, but their cumulative effects on downstream flows are less because they are located on ephemeral streams far in river headwaters.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC23G1307C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC23G1307C"><span>Assessing dam development, land use conversion, and climate change pressures on tributary river flows and water quality of the Mekong's Tonle Sap basin.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cochrane, T. A.; Arias, M. E.; Oeurng, C.; Arnaiz, M.; Piman, T.</p> <p>2016-12-01</p> <p>The Tonle Sap Lake is Southeast Asia's most productive freshwater fishery, but the productivity of this valuable ecosystem is under threat from extensive development in the lower Mekong. With dams potentially blocking all major tributaries along the lower Mekong River, the role of local Tonle Sap basin tributaries for maintaining environmental flows, sediment loads, and fish recruitment is becoming increasingly critical. Development within the Tonle Sap basin, however, is not stagnant. Developers are proposing extensive dam development in key Tonle Sap tributaries (see Figure). Some dams will provide hydroelectricity and others will provide opportunities for large-scale irrigation resulting in agro-industrial expansion. There is thus an immediate need to assess the current situation and understand future effects of dam development and land use conversion under climate change on local riverine ecosystems. A combination of remote sensing, field visits, and hydro-meteorological data analyses enabled an assessment of water infrastructure and agricultural development in the basin. The application of SWAT for modelling flows and water quality combined with HEC-RESSIM for reservoir operations enabled for a holistic modelling approach. Initial results show that dams and land use change dominate flow and water quality responses, when compared to climate change. Large ongoing dam and irrigation development in the Pursat and Battambang subbasins will critically alter the natural river flows to the Tonle Sap Lake. Some of the observed dams did not have provisions for sediment flushing, clearing of flooded areas, fish passages, or other environmental protection measures. Poor planning and operation of this infrastructure could have dire consequences on the fragile riverine ecosystem of Tonle Sap tributaries, resulting in fish migration barriers, losses in aquatic habitats, and ecological degradation. The seemingly chaotic development in the Tonle Sap basin induces a great level of complexity in the prediction of future change in flows, sediment, and nutrients to the Tonle Sap, which needs to be overcome with improved data gathering through tools such as remote sensing. Timely interventions to the current development is needed in order to alleviate future environmental pressures.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017RvGeo..55..818B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017RvGeo..55..818B"><span>Advances in understanding river-groundwater interactions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brunner, Philip; Therrien, René; Renard, Philippe; Simmons, Craig T.; Franssen, Harrie-Jan Hendricks</p> <p>2017-09-01</p> <p>River-groundwater interactions are at the core of a wide range of major contemporary challenges, including the provision of high-quality drinking water in sufficient quantities, the loss of biodiversity in river ecosystems, or the management of environmental flow regimes. This paper reviews state of the art approaches in characterizing and modeling river and groundwater interactions. Our review covers a wide range of approaches, including remote sensing to characterize the streambed, emerging methods to measure exchange fluxes between rivers and groundwater, and developments in several disciplines relevant to the river-groundwater interface. We discuss approaches for automated calibration, and real-time modeling, which improve the simulation and understanding of river-groundwater interactions. Although the integration of these various approaches and disciplines is advancing, major research gaps remain to be filled to allow more complete and quantitative integration across disciplines. New possibilities for generating realistic distributions of streambed properties, in combination with more data and novel data types, have great potential to improve our understanding and predictive capabilities for river-groundwater systems, especially in combination with the integrated simulation of the river and groundwater flow as well as calibration methods. Understanding the implications of different data types and resolution, the development of highly instrumented field sites, ongoing model development, and the ultimate integration of models and data are important future research areas. These developments are required to expand our current understanding to do justice to the complexity of natural systems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMEP43A1865O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMEP43A1865O"><span>The impact of engineered log jams on bed morphology, flow characteristics and habitat diversity under low flow</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ockelford, A.; Crabbe, E.; Crowe Curran, J.; Parsons, D. R.; Shugar, D. H.; Burr, A.; Kennedy, K.; Coe, T.</p> <p>2017-12-01</p> <p>Wood jams are an important and ubiquitous feature of many river channels with their number, placement and spatial configuration determining their influence on channel morphology and flow characteristics. Further, engineered log jams are increasingly being constructed to develop, restore or maintain habitat diversity for key indicator specie such as salmon. However, questions remain as to the inter relationships between the logjams, the channel morphology, the flow characteristics and the habitat diversity under low flow conditions. Four engineered and one natural logjam were analyzed over a 3km reach of the South Fork Nooksack River, North Cascades National Park, USA during the summer low flow period. Non-intrusive three-dimensional topographic surveys of the river bed morphology surrounding the logjams was collected using a shallow water multibeam system. This was combined with terrestrial laser scans of the structure of the log jams above the waterline. Co-located high resolution flow velocity data was collected using an Acoustic Doppler Current Profiler. Discussion concentrates on providing a quantitative understanding of the effect of logjams on reach scale morphodynamics under low flow conditions. Multivariate statistical analysis of flow and topographic data in combination with log jam morphology allow the influences of the logjam on habitat suitability for key indicator species to be quantified. Results will be framed in terms of the effectiveness of the different logjam configurations on generating and promoting habitat diversity such as to aid future design and implementation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AdWR...79..103G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AdWR...79..103G"><span>Inference of effective river properties from remotely sensed observations of water surface</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garambois, Pierre-André; Monnier, Jérôme</p> <p>2015-05-01</p> <p>The future SWOT mission (Surface Water and Ocean Topography) will provide cartographic measurements of inland water surfaces (elevation, widths and slope) at an unprecedented spatial and temporal resolution. Given synthetic SWOT like data, forward flow models of hierarchical-complexity are revisited and few inverse formulations are derived and assessed for retrieving the river low flow bathymetry, roughness and discharge (A0, K, Q) . The concept of an effective low flow bathymetry A0 (the real one being never observed) and roughness K , hence an effective river dynamics description, is introduced. The few inverse models elaborated for inferring (A0, K, Q) are analyzed in two contexts: (1) only remotely sensed observations of the water surface (surface elevation, width and slope) are available; (2) one additional water depth measurement (or estimate) is available. The inverse models elaborated are independent of data acquisition dynamics; they are assessed on 91 synthetic test cases sampling a wide range of steady-state river flows (the Froude number varying between 0.05 and 0.5 for 1 km reaches) and in the case of a flood on the Garonne River (France) characterized by large spatio-temporal variabilities. It is demonstrated that the most complete shallow-water like model allowing to separate the roughness and bathymetry terms is the so-called low Froude model. In Case (1), the resulting RMSE on infered discharges are on the order of 15% for first guess errors larger than 50%. An important feature of the present inverse methods is the fairly good accuracy of the discharge Q obtained, while the identified roughness coefficient K includes the measurement errors and the misfit of physics between the real flow and the hypothesis on which the inverse models rely; the later neglecting the unobserved temporal variations of the flow and the inertia effects. A compensation phenomena between the indentifiedvalues of K and the unobserved bathymetry A0 is highlighted, while the present inverse models lead to an effective river dynamics model that is accurate in the range of the discharge variability observed. In Case (2), the effective bathymetry profile for 80 km of the Garonne River is retrieved with 1% relative error only. Next, accurate effective topography-friction pairs and also discharge can be inferred. Finally, defining river reaches from the observation grid tends to average the river properties in each reach, hence tends to smooth the hydraulic variability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1815788S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1815788S"><span>The performance of the Hydromorphological Index of Diversity (HMID) in a hydropower affected meandering river</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stähly, Severin; Bourqui, Pierre; Franca, Mario J.; Robinson, Christopher; Schleiss, Anton J.</p> <p>2016-04-01</p> <p>More than half of the Swiss electricity is produced by hydropower. Large price fluctuations cause severe hydropeaking flow regimes due to corresponding production fluctuations, which undisputedly have a negative impact on aquatic biota. Water diversion due to dams on the other hand imposes downstream residual flow regimes. The absence of flood events and regular sediment supply disrupts sediment dynamics and disconnects floodplains, which are habitats of high value, from its main channel. The residual-flow controlled reach at the Sarine river in western Switzerland is the subject of the present study. The Sarine meanders strongly and the river reach under analysis has a bed incision of locally more than 100 m. Its incision provokes the isolation of the river which is consequently minimally touched by human structures and shows a natural geomorphology. Since the construction of a dam upstream this reach in 1948, aiming at the water abstraction to hydropower, vegetation could establish and the active floodplain decreased its area, as airborne images show. Nevertheless, it is classified as a floodplain of national importance and it has been under protection since 1992. It is supposed to be a valuable habitat for a wide range of organisms. The Hydromorphological Index of Diversity (HMID) is a simple tool for quantifying the habitat richness in a river reach, taking into account the mean values and the variation of water depth and flow velocity. For channelized rivers, HMID values from up to 5 are expected, while morphological pristine sites with a high spatial variability of water depth and velocity show values of 9 or higher. For the residual flow of the Sarine River, flow depth and velocity were measured using ADCP and ADV. The results are compared with a nearby natural reference river and the outcome of a 2D numerical simulation. Finally, the behaviour and limitations of the HMID, in a hydropower affected river, are discussed. In the close future an artificial flood is expected in the Sarine in order to reactivate the sediment dynamics. Using 2D numerical simulations in combination with a well understanding of the HMID an optimal planning of this event will be implemented. The present study is financed by the Swiss National Foundation (SNF), National Research Project 70, Energy Turnaround.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H13D1404M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H13D1404M"><span>The Effects of a Changing Climate and Urbanisation on River Flows in the Thames Basin, UK - a Hydrological Modelling Approach</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, J. D.; Rickards, N. J.; Kjeldsen, T. R.; Hutchins, M.; Rowland, C.; Prudhomme, C.; Maliko, T.; Fidal, J.; Hagen-Zanker, A.</p> <p>2016-12-01</p> <p>The UK population is set to increase by 16% by 2035; it is therefore increasingly important to understand the impact this may have on urban populations, and in turn how this will affect river flow regimes and water quality in urban areas. A growing population is likely to lead to an increase in urban land use and impervious surfaces, the implications of which are not yet fully understood for issues such as future flood risk. The aim of this paper is to develop a greater understanding of the impacts of both an increasing population and urban extent in the context of a changing climate, and to assess the effect these may have on urban streamflow regimes and water security in the future. Flows are modelled for selected catchments in the Thames basin using URBMOD, a lumped rainfall runoff model that is able to represent both pervious and impervious surfaces, reducing infiltration in catchments where there is a greater urban extent. The model uses daily catchment average rainfall and evapotranspiration derived from gridded data, and is calibrated against long-term river flow records. Historic satellite imagery is used to train cellular automata land use models, which are then applied under different scenarios of urban development up to 2035. These changes in land use are combined with a range of climate change scenarios to give an indication of how urban flow regimes may be altered in the Thames basin over the next 20 years. Results suggest an intensification of the hydrological regime in the majority of catchments, with increases in high flow magnitudes (Q10) of up to 5%. The trend for low flows (Q90) is less clear, with some catchments displaying reductions of around 4%, whilst others show slight increased flows. We identify the main drivers behind these changes, from which the fine-scale impacts of urbanisation on water resources can be better understood. Research findings are being used to inform a regional-scale model, coupling water quantity and quality and providing insight to urban planners and stakeholders on the future urban hydrological regime in the Thames basin. Similar approaches are being used to assess impacts of anthropogenic drivers on water resources in the Cauvery basin in India, whereby the applicability of the model under very different climate and urban morphology will be tested.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1224915','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1224915"><span>Identifying and Mitigating Potential Nutrient and Sediment Hot Spots under a Future Scenario in the Missouri River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Wu, May; Zhang, Zhonglong</p> <p></p> <p>Using the Soil and Water Assessment Tool (SWAT) for large-scale watershed modeling could be useful for evaluating the quality of the water in regions that are dominated by nonpoint sources in order to identify potential “hot spots” for which mitigating strategies could be further developed. An analysis of water quality under future scenarios in which changes in land use would be made to accommodate increased biofuel production was developed for the Missouri River Basin (MoRB) based on a SWAT model application. The analysis covered major agricultural crops and biofuel feedstock in the MoRB, including pasture land, hay, corn, soybeans, wheat,more » and switchgrass. The analysis examined, at multiple temporal and spatial scales, how nitrate, organic nitrogen, and total nitrogen; phosphorus, organic phosphorus, inorganic phosphorus, and total phosphorus; suspended sediments; and water flow (water yield) would respond to the shifts in land use that would occur under proposed future scenarios. The analysis was conducted at three geospatial scales: (1) large tributary basin scale (two: Upper MoRB and Lower MoRB); (2) regional watershed scale (seven: Upper Missouri River, Middle Missouri River, Middle Lower Missouri River, Lower Missouri River, Yellowstone River, Platte River, and Kansas River); and (3) eight-digit hydrologic unit (HUC-8) subbasin scale (307 subbasins). Results showed that subbasin-level variations were substantial. Nitrogen loadings decreased across the entire Upper MoRB, and they increased in several subbasins in the Lower MoRB. Most nitrate reductions occurred in lateral flow. Also at the subbasin level, phosphorus in organic, sediment, and soluble forms was reduced by 35%, 45%, and 65%, respectively. Suspended sediments increased in 68% of the subbasins. The water yield decreased in 62% of the subbasins. In the Kansas River watershed, the water quality improved significantly with regard to every nitrogen and phosphorus compound. The improvement was clearly attributable to the conversion of a large amount of land to switchgrass. The Middle Lower Missouri River and Lower Missouri River were identified as hot regions. Further analysis identified four subbasins (10240002, 10230007, 10290402, and 10300200) as being the most vulnerable in terms of sediment, nitrogen, and phosphorus loadings. Overall, results suggest that increasing the amount of switchgrass acreage in the hot spots should be considered to mitigate the nutrient loads. The study provides an analytical method to support stakeholders in making informed decisions that balance biofuel production and water sustainability.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy...50..215S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy...50..215S"><span>Future changes in peak river flows across northern Eurasia as inferred from an ensemble of regional climate projections under the IPCC RCP8.5 scenario</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shkolnik, Igor; Pavlova, Tatiana; Efimov, Sergey; Zhuravlev, Sergey</p> <p>2018-01-01</p> <p>Climate change simulation based on 30-member ensemble of Voeikov Main Geophysical Observatory RCM (resolution 25 km) for northern Eurasia is used to drive hydrological model CaMa-Flood. Using this modeling framework, we evaluate the uncertainties in the future projection of the peak river discharge and flood hazard by 2050-2059 relative to 1990-1999 under IPCC RCP8.5 scenario. Large ensemble size, along with reasonably high modeling resolution, allows one to efficiently sample natural climate variability and increase our ability to predict future changes in the hydrological extremes. It has been shown that the annual maximum river discharge can almost double by the mid-XXI century in the outlets of major Siberian rivers. In the western regions, there is a weak signal in the river discharge and flood hazard, hardly discernible above climate variability. Annual maximum flood area is projected to increase across Siberia mostly by 2-5% relative to the baseline period. A contribution of natural climate variability at different temporal scales to the uncertainty of ensemble prediction is discussed. The analysis shows that there expected considerable changes in the extreme river discharge probability at locations of the key hydropower facilities. This suggests that the extensive impact studies are required to develop recommendations for maintaining regional energy security.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JHyd..519..743V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JHyd..519..743V"><span>Intercomparison of hydrological model structures and calibration approaches in climate scenario impact projections</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vansteenkiste, Thomas; Tavakoli, Mohsen; Ntegeka, Victor; De Smedt, Florimond; Batelaan, Okke; Pereira, Fernando; Willems, Patrick</p> <p>2014-11-01</p> <p>The objective of this paper is to investigate the effects of hydrological model structure and calibration on climate change impact results in hydrology. The uncertainty in the hydrological impact results is assessed by the relative change in runoff volumes and peak and low flow extremes from historical and future climate conditions. The effect of the hydrological model structure is examined through the use of five hydrological models with different spatial resolutions and process descriptions. These were applied to a medium sized catchment in Belgium. The models vary from the lumped conceptual NAM, PDM and VHM models over the intermediate detailed and distributed WetSpa model to the fully distributed MIKE SHE model. The latter model accounts for the 3D groundwater processes and interacts bi-directionally with a full hydrodynamic MIKE 11 river model. After careful and manual calibration of these models, accounting for the accuracy of the peak and low flow extremes and runoff subflows, and the changes in these extremes for changing rainfall conditions, the five models respond in a similar way to the climate scenarios over Belgium. Future projections on peak flows are highly uncertain with expected increases as well as decreases depending on the climate scenario. The projections on future low flows are more uniform; low flows decrease (up to 60%) for all models and for all climate scenarios. However, the uncertainties in the impact projections are high, mainly in the dry season. With respect to the model structural uncertainty, the PDM model simulates significantly higher runoff peak flows under future wet scenarios, which is explained by its specific model structure. For the low flow extremes, the MIKE SHE model projects significantly lower low flows in dry scenario conditions in comparison to the other models, probably due to its large difference in process descriptions for the groundwater component, the groundwater-river interactions. The effect of the model calibration was tested by comparing the manual calibration approach with automatic calibrations of the VHM model based on different objective functions. The calibration approach did not significantly alter the model results for peak flow, but the low flow projections were again highly influenced. Model choice as well as calibration strategy hence have a critical impact on low flows, more than on peak flows. These results highlight the high uncertainty in low flow modelling, especially in a climate change context.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2016/5180/sir20165180.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2016/5180/sir20165180.pdf"><span>Hydrogeology and simulation of groundwater flow and analysis of projected water use for the Canadian River alluvial aquifer, western and central Oklahoma</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ellis, John H.; Mashburn, Shana L.; Graves, Grant M.; Peterson, Steven M.; Smith, S. Jerrod; Fuhrig, Leland T.; Wagner, Derrick L.; Sanford, Jon E.</p> <p>2017-02-13</p> <p>This report describes a study of the hydrogeology and simulation of groundwater flow for the Canadian River alluvial aquifer in western and central Oklahoma conducted by the U.S. Geological Survey in cooperation with the Oklahoma Water Resources Board. The report (1) quantifies the groundwater resources of the Canadian River alluvial aquifer by developing a conceptual model, (2) summarizes the general water quality of the Canadian River alluvial aquifer groundwater by using data collected during August and September 2013, (3) evaluates the effects of estimated equal proportionate share (EPS) on aquifer storage and streamflow for time periods of 20, 40, and 50 years into the future by using numerical groundwater-flow models, and (4) evaluates the effects of present-day groundwater pumping over a 50-year period and sustained hypothetical drought conditions over a 10-year period on stream base flow and groundwater in storage by using numerical flow models. The Canadian River alluvial aquifer is a Quaternary-age alluvial and terrace unit consisting of beds of clay, silt, sand, and fine gravel sediments unconformably overlying Tertiary-, Permian-, and Pennsylvanian-age sedimentary rocks. For groundwater-flow modeling purposes, the Canadian River was divided into Reach I, extending from the Texas border to the Canadian River at the Bridgeport, Okla., streamgage (07228500), and Reach II, extending downstream from the Canadian River at the Bridgeport, Okla., streamgage (07228500), to the confluence of the river with Eufaula Lake. The Canadian River alluvial aquifer spans multiple climate divisions, ranging from semiarid in the west to humid subtropical in the east. The average annual precipitation in the study area from 1896 to 2014 was 34.4 inches per year (in/yr).A hydrogeologic framework of the Canadian River alluvial aquifer was developed that includes the areal and vertical extent of the aquifer and the distribution, texture variability, and hydraulic properties of aquifer materials. The aquifer areal extent ranged from less than 0.2 to 8.5 miles wide. The maximum aquifer thickness was 120 feet (ft), and the average aquifer thickness was 50 ft. Average horizontal hydraulic conductivity for the Canadian River alluvial aquifer was calculated to be 39 feet per day, and the maximum horizontal hydraulic conductivity was calculated to be 100 feet per day.Recharge rates to the Canadian River alluvial aquifer were estimated by using a soil-water-balance code to estimate the spatial distribution of groundwater recharge and a water-table fluctuation method to estimate localized recharge rates. By using daily precipitation and temperature data from 39 climate stations, recharge was estimated to average 3.4 in/yr, which corresponds to 8.7 percent of precipitation as recharge for the Canadian River alluvial aquifer from 1981 to 2013. The water-table fluctuation method was used at one site where continuous water-level observation data were available to estimate the percentage of precipitation that becomes groundwater recharge. Estimated annual recharge at that site was 9.7 in/yr during 2014.Groundwater flow in the Canadian River alluvial aquifer was identified and quantified by a conceptual flow model for the period 1981–2013. Inflows to the Canadian River alluvial aquifer include recharge to the water table from precipitation, lateral flow from the surrounding bedrock, and flow from the Canadian River, whereas outflows include flow to the Canadian River (base-flow gain), evapotranspiration, and groundwater use. Total annual recharge inflows estimated by the soil-water-balance code were multiplied by the area of each reach and then averaged over the simulated period to produce an annual average of 28,919 acre-feet per year (acre-ft/yr) for Reach I and 82,006 acre-ft/yr for Reach II. Stream base flow to the Canadian River was estimated to be the largest outflow of groundwater from the aquifer, measured at four streamgages, along with evapotranspiration and groundwater use, which were relatively minor discharge components.Objectives for the numerical groundwater-flow models included simulating groundwater flow in the Canadian River alluvial aquifer from 1981 to 2013 to address groundwater use and drought scenarios, including calculation of the EPS pumping rates. The EPS for the alluvial and terrace aquifers is defined by the Oklahoma Water Resources Board as the amount of fresh water that each landowner is allowed per year per acre of owned land to maintain a saturated thickness of at least 5 ft in at least 50 percent of the overlying land of the groundwater basin for a minimum of 20 years.The groundwater-flow models were calibrated to water-table altitude observations, streamgage base flows, and base-flow gain to the Canadian River. The Reach I water-table altitude observation root-mean-square error was 6.1 ft, and 75 percent of residuals were within ±6.7 ft of observed measurements. The average simulated stream base-flow residual at the Bridgeport streamgage (07228500) was 8.8 cubic feet per second (ft3/s), and 75 percent of residuals were within ±30 ft3/s of observed measurements. Simulated base-flow gain in Reach I was 8.8 ft3/s lower than estimated base-flow gain. The Reach II water-table altitude observation root-mean-square error was 4 ft, and 75 percent of residuals were within ±4.3 ft of the observations. The average simulated stream base-flow residual in Reach II was between 35 and 132 ft3/s. The average simulated base-flow gain residual in Reach II was between 11.3 and 61.1 ft3/s.Several future predictive scenarios were run, including estimating the EPS pumping rate for 20-, 40-, and 50-year life of basin scenarios, determining the effects of current groundwater use over a 50-year period into the future, and evaluating the effects of a sustained drought on water availability for both reaches. The EPS pumping rate was determined to be 1.35 acre-feet per acre per year ([acre-ft/acre]/yr) in Reach I and 3.08 (acre-ft/acre)/yr in Reach II for a 20-year period. For the 40- and 50-year periods, the EPS rate was determined to be 1.34 (acre-ft/acre)/yr in Reach I and 3.08 (acre-ft/acre)/yr in Reach II. Storage changes decreased in tandem with simulated groundwater pumping and were minimal after the first 15 simulated years for Reach I and the first 8 simulated years for Reach II.Groundwater pumping at year 2013 rates for a period of 50 years resulted in a 0.2-percent decrease in groundwater-storage volumes in Reach I and a 0.6-percent decrease in the groundwater-storage volumes in Reach II. The small changes in storage are due to groundwater use by pumping, which composes a small percentage of the total groundwater-flow model budgets for Reaches I and II.A sustained drought scenario was used to evaluate the effects of a hypothetical 10-year drought on water availability. A 10-year period was chosen where the effects of drought conditions would be simulated by decreasing recharge by 75 percent. In Reach I, average simulated stream base flow at the Bridgeport streamgage (07228500) decreased by 58 percent during the hypothetical 10-year drought compared to average simulated stream base flow during the nondrought period. In Reach II, average simulated stream base flows at the Purcell streamgage (07229200) and Calvin streamgage (07231500) decreased by 64 percent and 54 percent, respectively. In Reach I, the groundwater-storage drought scenario resulted in a storage decline of 30 thousand acre-feet, or an average decline in the water table of 1.2 ft. In Reach II, the groundwater-storage drought scenario resulted in a storage decline of 71 thousand acre-feet, or an average decline in the water table of 2.0 ft.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2010/5114/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2010/5114/"><span>Estimation of the effects of land use and groundwater withdrawals on streamflow for the Pomperaug River, Connecticut</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bjerklie, David M.; Starn, J. Jeffrey; Tamayo, Claudia</p> <p>2010-01-01</p> <p>A precipitation runoff model for the Pomperaug River watershed, Connecticut was developed to address issues of concern including the effect of development on streamflow and groundwater recharge, and the implications of water withdrawals on streamflow. The model was parameterized using a strategy that requires a minimum of calibration and optimization by establishing basic relations between the parameter value and physical characteristics of individual hydrologic response units (HRUs) that comprise the model. The strategy was devised so that the information needed can be obtained from Geographic Information System and other general databases for Connecticut. Simulation of groundwater recharge enabled evaluation of the temporal and spatial mapping of recharge variation across the watershed and the spatial effects of changes in land cover on base flow and surface runoff. The modeling indicated that over the course of a year, groundwater provides between 60 and 70 percent of flow in the Pomperaug River; the remainder is generated by more rapid flow through the shallow subsurface and runoff from impermeable surfaces and saturated ground. Groundwater is recharged primarily during periods of low evapotranspiration in the winter, spring, and fall. The largest amount of recharge occurs in the spring in response to snowmelt. During floods, the Weekeepeemee and Nonnewaug Rivers (tributaries that form the Pomperaug River) respond rapidly with little flood peak attenuation due to flood-plain storage. In the Pomperaug River, flood-plain storage is more important in attenuating floods; abandoned quarry ponds (O&G ponds) adjacent to the river provide substantial flood storage above specific river stages when flow from the river spills over the banks and fills the ponds. Discharge from the ponds also helps to sustain low flows in the Pomperaug River. Similarly, releases from the Bronson-Lockwood reservoir sustain flow in the Nonnewaug River and tend to offset the effect of groundwater withdrawals from a well field adjacent to the river during periods of natural low flow. The model indicated that under the current zoning, future development could reduce low flows by as much as 10 percent at the 99 percent exceedance level (99 percent of flows are greater than or equal to this flow), but would not substantially increase the highest flows. Simulation of projected and hypothetical development in the watershed shows, depending on how stormwater is managed, that between 10 and 20 percent effective impervious area in an HRU results in streamflow becoming dominated by the surface-runoff component. This shift from a groundwater-dominated system would likely result in substantial changes in water quality and instream habitat characteristics of the river. Base flow to streams in the Pomperaug River watershed is reduced by both increased impervious surface and increased groundwater withdrawals. For the watershed as a whole, increasing groundwater withdrawals have the potential for causing greater overall reductions in flow compared to increased development and impervious surfaces. Additionally, on the basis of groundwater-modeling simulations, the projected increase in development across the watershed and, to a lesser extent the increase in groundwater withdrawals, will increase the number of local losing reaches experiencing dry conditions and the duration of these dry periods. The location of the losing reaches tends to be in areas near the transition from the uplands to the valley bottoms that are filled with coarse glacial stratified deposits. The simulated increase in the duration and extent of localized dry stream reaches is most sensitive to local increase in impervious surface. Conversion of land from forest or developed land cover to pasture or agricultural land increases groundwater recharge and discharge to streams, while at the same time increasing overall streamflow (the opposite effect as increased impervious surface). These resu</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.1746P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.1746P"><span>Role of hydrological events in sediment and sediment-associated heavy metals transport within a continental transboundary river system - Tuul River case study (Mongolia)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pietroń, Jan; Jarsjö, Jerker</p> <p>2013-04-01</p> <p>The concentration of heavy metals in rivers is often greater in the sediment load than in the water solution. Overall, heavy metal conveyance with sediment transport is a significant contributor to the global transport of heavy metals. Heavy metals once released to a river system may remain in the deposits of the river from short to very long times, for instance depending on to which extent erosion and deposition can influence the sediment mass stored in the river bed. In general, the mobility of contaminated sediments to downstream water recipients may to large extent be governed by natural sediment transport dynamics during hydrological events, such as flow peaks following heavy rainfalls. The Tuul River (Northern Mongolia) belongs to a Tuul River-Orkhon River-Selenga River- transboundary river system that discharges into Lake Baikal. The river system is largely characterized by its natural hydrological regime with numerous rapid peak flow events of the spring-summer periods. However, recent studies indicate contamination of fine sediment with heavy metals coming from placer gold mining area (Zaamar Goldfield) located along the downstream Tuul River. In this work, the general idea is to create a one-dimensional sediment transport model of the downstream Tuul River, and use field-data supported modeling to investigate natural erosion-deposition rates and the role of peak flows in natural sediment transport at 14 km reach just downstream the gold mining area. The model results show that the sediment load of the finest investigated grain size has a great potential to be eroded from the bed of the studied reach, especially during the main peak flow events. However, the same events are associated with a significant deposition of the finest material. The model results also show different hysteresis behavior of the sediment load rating curves (clockwise and counter-clockwise) during the main peak flow events. These are interpreted as effects of changing in-channel sediment supplies due to sorting method applied in the model. More generally, the modelling may increase our knowledge about the sediment transport patterns of the reach downstream the mining area. This part of the river may be considered as a temporal sink of heavy metals which may accumulate and store sediments. The deposition in such sinks can considerably support attenuation of contaminated sediment loads. On the other hand, sediments that are accumulated in sinks can increase the concentration of contaminated sediment loads during peak flow events. Information about the rates of eroded and accumulated contaminated material in such sinks is important for future water protection planning, especially under changing climate conditions. This work may also provide scientific input to discussions on both adverse environmental consequences of placer mining, and suitable designs of sediment control measures in the Zaamar Goldfield and other continental river systems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/11661','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/11661"><span>A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for East Fork White River, Bartholomew County, Indiana</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wilber, William G.; Peters, James G.; Crawford, Charles G.</p> <p>1979-01-01</p> <p>A digital model calibrated to conditions in East Fork White River, Bartholomew County, IN, was used to develop alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. The model indicates that benthic-oxygen demand and the headwater concentrations of carbonaceous biochemical-oxygen demand, nitrogenous biochemical-oxygen demand, and dissolved oxygen are the most significant factors affecting the dissolved-oxygen concentration of East Fork White River downstream from the Columbus wastewater-treatment facility. The effect of effluent from the facility on the water quality of East Fork White River was minimal. The model also indicates that, with a benthic-oxygen demand of approximately 0.65 gram per square meter per day, the stream has no additional waste-load assimilative capacity during summer low flows. Regardless of the quality of the Columbus wastewater effluent, the minimum 24-hour average dissolved-oxygen concentration of at least 5 milligrams per liter, the State 's water-quality standard for streams, would not be met. Ammonia toxicity is not a limiting water-quality criterion during summer and winter low flows. During winter low flows, the current carbonaceous biochemical-oxygen demand limits for the Columbus wastewater-treatment facility will not result in violations of the in-stream dissolved-oxygen standard. (USGS)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1259805','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1259805"><span>Power Generation for River and Tidal Generators</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Muljadi, Eduard; Wright, Alan; Gevorgian, Vahan</p> <p></p> <p>Renewable energy sources are the second largest contributor to global electricity production, after fossil fuels. The integration of renewable energy continued to grow in 2014 against a backdrop of increasing global energy consumption and a dramatic decline in oil prices during the second half of the year. As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded from primarily wind and solar to include new types with promising future applications, such as hydropower generation, including river and tidal generation. Today, hydropower is considered onemore » of the most important renewable energy sources. In river and tidal generation, the input resource flow is slower but also steadier than it is in wind or solar generation, yet the level of water turbulent flow may vary from one place to another. This report focuses on hydrokinetic power conversion.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6551D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6551D"><span>Water surface elevation from the upcoming SWOT mission under different flows conditions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Domeneghetti, Alessio; Schumann, Guy J. P.; Wei, Rui; Frasson, Renato P. M.; Durand, Michael; Pavelsky, Tamlin; Castellarin, Attilio; Brath, Armando</p> <p>2017-04-01</p> <p>The upcoming SWOT (Surface Water and Ocean Topography) satellite mission will provide unprecedented bi-dimensional observations of terrestrial water surface heights along rivers wider than 100m. Despite the literature reports several activities showing possible uses of SWOT products, potential and limitations of satellite observations still remain poorly understood and investigated. We present one of the first analyses regarding the spatial observation of water surface elevation expected from SWOT for a 140 km reach of the middle-lower portion of the Po River, in Northern Italy. The river stretch is characterized by a main channel varying from 100-500 m in width and a floodplain delimited by a system of major embankments that can be as wide as 5 km. The reconstruction of the hydraulic behavior of the Po River is performed by means of a quasi-2D model built with detailed topographic and bathymetric information (LiDAR, 2m resolution), while the simulation of remotely sensed hydrometric data is performed with a SWOT simulator that mimics the satellite sensor characteristics. Referring to water surface elevations associated with different flow conditions (maximum, minimum and average flow) this work characterizes the spatial observations provided by SWOT and highlights the strengths and limitations of the expected products. The analysis provides a robust reference for spatial water observations that will be available from SWOT and assesses possible effects of river embankments, river width and river topography under different hydraulic conditions. Results of the study characterize the expected accuracy of the upcoming SWOT mission and provide additional insights towards the appropriate exploitation of future hydrological observations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMGC43C0750M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMGC43C0750M"><span>Assessing Potential Implications of Climate Change for Long-Term Water Resources Planning in the Colorado River Basin, Texas</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Munevar, A.; Butler, S.; Anderson, R.; Rippole, J.</p> <p>2008-12-01</p> <p>While much of the focus on climate change impacts to water resources in the western United States has been related to snow-dominated watersheds, lower elevation basins such as the Colorado River Basin in Texas are dependent on rainfall as the predominant form of precipitation and source of supply. Water management in these basins has evolved to adapt to extreme climatic and hydrologic variability, but the impact of climate change is potentially more acute due to rapid runoff response and subsequent greater soil moisture depletion during the dry seasons. The Lower Colorado River Authority (LCRA) - San Antonio Water System (SAWS) Water Project is being studied to conserve water, develop conjunctive groundwater supplies, and capture excess and unused river flows to meet future water needs for two neighboring regions in Texas. Agricultural and other rural water needs would be met on a more reliable basis in the lower Colorado River Basin through water conservation, surface water development and limited groundwater production. Surface water would be transferred to the San Antonio area to meet municipal needs in quantities still being evaluated. Detailed studies are addressing environmental, agricultural, socioeconomic, and engineering aspects of the project. Key planning activities include evaluating instream flow criteria, water quality, bay freshwater inflow criteria, surface water availability and operating approaches, agricultural conservation measures, groundwater availability, and economics. Models used to estimate future water availability and environmental flow requirements have been developed largely based on historical observed hydrologic data. This is a common approach used by water planners as well as by many regulatory agencies for permit review. In view of the project's 80-yr planning horizon, contractual obligations, comments from the Science Review Panel, and increased public and regulatory awareness of climate change issues, the project team is exploring climate change projections and methods to assess potential impacts over the project's expected life. Following an initial qualitative risk assessment, quantitative climate scenarios were developed based on multiple coupled atmosphere-ocean general circulation model (AOGCM) simulations under a range of global emission scenarios. Projected temperature and precipitation changes were evaluated from 112 downscaled AOGCM projections. A Four scenarios were selected for detailed hydrologic evaluations using the Variable Infiltration Capacity (VIC) macroscale model. A quantile mapping procedure was applied to map future climatological period change statistics onto the long-term natural climate variability in the observed record. Simulated changes in runoff, river flow, evaporation, and evapotranspiration are used to generate adjustments to historical hydrology for assessment of potential changes to surface water availability, river water quality, riverine habitat, and Bay health. Projected temperature, precipitation, and atmospheric CO2 concentrations are used to estimate changes in agricultural demand. Sea level rise scenarios that include trends in Gulf Coast shelf subsidence are combined with changes in inflows to evaluate increased coastal erosion, upland migration of the estuary, and changes to the salinity regime. Results of the scenario-based analyses are being considered in the development of adaptive management strategies for future operations of the system and the proposed project.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.bioone.org/doi/abs/10.3955/046.090.0106','USGSPUBS'); return false;" href="http://www.bioone.org/doi/abs/10.3955/046.090.0106"><span>Combined effects of projected sea level rise, storm surge, and peak river flows on water levels in the Skagit Floodplain</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hamman, Josheph J; Hamlet, Alan F.; Fuller, Roger; Grossman, Eric E.</p> <p>2016-01-01</p> <p>Current understanding of the combined effects of sea level rise (SLR), storm surge, and changes in river flooding on near-coastal environments is very limited. This project uses a suite of numerical models to examine the combined effects of projected future climate change on flooding in the Skagit floodplain and estuary. Statistically and dynamically downscaled global climate model scenarios from the ECHAM-5 GCM were used as the climate forcings. Unregulated daily river flows were simulated using the VIC hydrology model, and regulated river flows were simulated using the SkagitSim reservoir operations model. Daily tidal anomalies (TA) were calculated using a regression approach based on ENSO and atmospheric pressure forcing simulated by the WRF regional climate model. A 2-D hydrodynamic model was used to estimate water surface elevations in the Skagit floodplain using resampled hourly hydrographs keyed to regulated daily flood flows produced by the reservoir simulation model, and tide predictions adjusted for SLR and TA. Combining peak annual TA with projected sea level rise, the historical (1970–1999) 100-yr peak high water level is exceeded essentially every year by the 2050s. The combination of projected sea level rise and larger floods by the 2080s yields both increased flood inundation area (+ 74%), and increased average water depth (+ 25 cm) in the Skagit floodplain during a 100-year flood. Adding sea level rise to the historical FEMA 100-year flood resulted in a 35% increase in inundation area by the 2040's, compared to a 57% increase when both SLR and projected changes in river flow were combined.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdWR..108..332N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdWR..108..332N"><span>Hydroclimatic sustainability assessment of changing climate on cholera in the Ganges-Brahmaputra basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nasr-Azadani, Fariborz; Khan, Rakibul; Rahimikollu, Javad; Unnikrishnan, Avinash; Akanda, Ali; Alam, Munirul; Huq, Anwar; Jutla, Antarpreet; Colwell, Rita</p> <p>2017-10-01</p> <p>The association of cholera and climate has been extensively documented. However, determining the effects of changing climate on the occurrence of disease remains a challenge. Bimodal peaks of cholera in Bengal Delta are hypothesized to be linked to asymmetric flow of the Ganges and Brahmaputra rivers. Spring cholera is related to intrusion of bacteria-laden coastal seawater during low flow seasons, while autumn cholera results from cross-contamination of water resources when high flows in the rivers cause massive inundation. Coarse resolution of General Circulation Model (GCM) output (usually at 100 - 300 km)cannot be used to evaluate variability at the local scale(10-20 km),hence the goal of this study was to develop a framework that could be used to understand impacts of climate change on occurrence of cholera. Instead of a traditional approach of downscaling precipitation, streamflow of the two rivers was directly linked to GCM outputs, achieving reasonable accuracy (R2 = 0.89 for the Ganges and R2 = 0.91 for the Brahmaputra)using machine learning algorithms (Support Vector Regression-Particle Swarm Optimization). Copula methods were used to determine probabilistic risks of cholera under several discharge conditions. Key results, using model outputs from ECHAM5, GFDL, andHadCM3for A1B and A2 scenarios, suggest that the combined low flow of the two rivers may increase in the future, with high flows increasing for first half of this century, decreasing thereafter. Spring and autumn cholera, assuming societal conditions remain constant e.g., at the current rate, may decrease. However significant shifts were noted in the magnitude of river discharge suggesting that cholera dynamics of the delta may well demonstrate an uncertain predictable pattern of occurrence over the next century.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2012/3073/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2012/3073/"><span>Development of computational fluid dynamics--habitat suitability (CFD-HSI) models to identify potential passage--Challenge zones for migratory fishes in the Penobscot River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Haro, Alexander J.; Dudley, Robert W.; Chelminski, Michael</p> <p>2012-01-01</p> <p>A two-dimensional computational fluid dynamics-habitat suitability (CFD–HSI) model was developed to identify potential zones of shallow depth and high water velocity that may present passage challenges for five anadromous fish species in the Penobscot River, Maine, upstream from two existing dams and as a result of the proposed future removal of the dams. Potential depth-challenge zones were predicted for larger species at the lowest flow modeled in the dam-removal scenario. Increasing flows under both scenarios increased the number and size of potential velocity-challenge zones, especially for smaller species. This application of the two-dimensional CFD–HSI model demonstrated its capabilities to estimate the potential effects of flow and hydraulic alteration on the passage of migratory fish.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H43R..07Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H43R..07Y"><span>Freshwater Ecosystem Services and Hydrologic Alteration in the Lower Mississippi River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yasarer, L.; Taylor, J.; Rigby, J.; Locke, M. A.</p> <p>2017-12-01</p> <p>Flowing freshwater ecosystems provide a variety of essential ecosystem services including: consumptive water for domestic, industrial, and agricultural use; transportation of goods; maintenance of aquatic biodiversity and water quality; and recreation. However, freshwater ecosystem services can oftentimes be at odds with each other. For example, the over-consumption of water for agricultural production or domestic use may alter hydrologic patterns and diminish the ability of flowing waters to sustain healthy aquatic ecosystems. In the Lower Mississippi River Basin there has been a substantial increase in groundwater-irrigated cropland acreage over the past several decades and subsequent declines in regional aquifer levels. Changes in aquifer levels potentially impact surface water hydrology throughout the region. This study tests the hypothesis that flowing water systems in lowland agricultural watersheds within the Lower Mississippi River Basin have greater hydrologic alteration compared to upland non-agricultural watersheds, particularly with declines in base flow and an increase in extreme low flows. Long-term streamflow records from USGS gauges located in predominantly agricultural and non-agricultural watersheds in Arkansas, Louisiana, Mississippi, and Tennessee were evaluated from 1969 -2016 using the Indicators of Hydrologic Alteration (IHA) software. Preliminary results from 8 non-agricultural and 5 agricultural watersheds demonstrate a substantial decline in base flow in the agricultural watersheds, which is not apparent in the non-agricultural watersheds. This exploratory study will analyze the trade-off between gains in agricultural productivity and changes in ecohydrological indicators over the last half century in diverse watersheds across the Lower Mississippi River Basin. By quantifying the changes in ecosystem services provided by flowing waters in the past, we can inform sustainable management pathways to better balance services in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGC21B0837Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGC21B0837Z"><span>Simulating Freshwater Availability under Future Climate Conditions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, F.; Zeng, N.; Motesharrei, S.; Gustafson, K. C.; Rivas, J.; Miralles-Wilhelm, F.; Kalnay, E.</p> <p>2013-12-01</p> <p>Freshwater availability is a key factor for regional development. Precipitation, evaporation, river inflow and outflow are the major terms in the estimate of regional water supply. In this study, we aim to obtain a realistic estimate for these variables from 1901 to 2100. First we calculated the ensemble mean precipitation using the 2011-2100 RCP4.5 output (re-sampled to half-degree spatial resolution) from 16 General Circulation Models (GCMs) participating the Coupled Model Intercomparison Project Phase 5 (CMIP5). The projections are then combined with the half-degree 1901-2010 Climate Research Unit (CRU) TS3.2 dataset after bias correction. We then used the combined data to drive our UMD Earth System Model (ESM), in order to generate evaporation and runoff. We also developed a River-Routing Scheme based on the idea of Taikan Oki, as part of the ESM. It is capable of calculating river inflow and outflow for any region, driven by the gridded runoff output. River direction and slope information from Global Dominant River Tracing (DRT) dataset are included in our scheme. The effects of reservoirs/dams are parameterized based on a few simple factors such as soil moisture, population density and geographic regions. Simulated river flow is validated with river gauge measurements for the world's major rivers. We have applied our river flow calculation to two data-rich watersheds in the United States: Phoenix AMA watershed and the Potomac River Basin. The results are used in our SImple WAter model (SIWA) to explore water management options.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/5224886','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/5224886"><span>Quantifying the extent of river fragmentation by hydropower dams in the Sarapiquí River Basin, Costa Rica</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Anderson, Elizabeth P.; Pringle, Catherine M.; Freeman, Mary C.</p> <p>2008-01-01</p> <p>Costa Rica has recently experienced a rapid proliferation of dams for hydropower on rivers draining its northern Caribbean slope. In the Sarapiquí River Basin, eight hydropower plants were built between 1990 and 1999 and more projects are either under construction or proposed. The majority of these dams are small (<15 m tall) and operate as water diversion projects.While the potential environmental effects of individual projects are evaluated prior to dam construction, there is a need for consideration of the basin-scale ecological consequences of hydropower development. This study was a first attempt to quantify the extent of river fragmentation by dams in the Sarapiquí River Basin.Using simple spatial analyses, the length of river upstream from dams and the length of de-watered reaches downstream from dams was measured. Results indicated that there are currently 306.8 km of river (9.4% of the network) upstream from eight existing dams in the Sarapiquí River Basin and 30.6 km of rivers (0.9% of the network) with significantly reduced flow downstream from dams. Rivers upstream from dams primarily drain two life zones: Premontane Rain Forest (107.9 km) and Lower Montane Rain Forest (168.2 km).Simple spatial analyses can be used as a predictive or planning tool for considering the effects of future dams in a basin-scale context. In the Sarapiquí River Basin, we recommend that future dam projects be constructed on already dammed rivers to minimize additional river fragmentation and to protect remaining riverine connectivity.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22572801','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22572801"><span>Variable-source flood pulsing in a semi-arid transboundary watershed: the Chobe River, Botswana and Namibia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pricope, Narcisa G</p> <p>2013-02-01</p> <p>The Chobe River, characterized by an unusual flood pulsing regime and shared between Botswana and Namibia, lies at the heart of the world's largest transfrontier conservation area (the Kavango-Zambezi Transfrontier Conservation Area). Significant ecological changes and vegetation conversions are occurring along its floodplains. Various scenarios for agricultural and urban water use are currently being proposed by the government of Botswana. However, the understanding of the river's annual flow regime and timing of the relative contributions of water from three different sources is relatively poor. In light of past and future climate change and variability, this means that allocating water between ecological flows and economic and domestic uses will become increasingly challenging. We reconstruct the inundation history in this basin to help ease this challenge. This paper presents a spatiotemporal approach to estimate the contribution of water from various sources and the magnitude of changes in the flooding extent in the basin between 1985 and 2010. We used time series analysis of bimonthly NOAA AVHRR and NASA MODIS data and climatologic and hydrologic records to determine the flooding timing and extent. The results indicate that between 12 and 62 % of the basin is flooded on an annual basis and that the spatial extent of the flooding varies throughout the year as a function of the timing of peak discharge in two larger basins. A 30-year trend analysis indicates a consistent decline in the average monthly flooded area in the basin. The results may prove useful in future water utilization feasibility studies, in determining measures for protecting ecological flows and levels, and in ecosystem dynamics studies in the context of current and future climate change and variability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC43C1177B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC43C1177B"><span>On the Edge: the Impact of Climate Change, Climate Extremes, and Climate-driven Disturbances on the Food-Energy-Water Nexus in the Colorado River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bennett, K. E.; McDowell, N. G.; Tidwell, V. C.; Xu, C.; Solander, K.; Jonko, A. K.; Wilson, C. J.; Middleton, R. S.</p> <p>2016-12-01</p> <p>The Colorado River Basin (CRB) is a critical watershed in terms of vulnerability to climate change and supporting the food-energy-water nexus. Climate-driven disturbances in the CRB—including wildfire, drought, and pests—threaten the watershed's ability to reliably support a wide array of ecosystem services while meeting the interrelated demands of the food-energy-water nexus. Our work illustrates future changes for upper Colorado River headwater basins using the Variable Infiltration Capacity hydrologic model driven by downscaled CMIP5 global climate data coupled with pseudo-dynamic vegetation shifts associated with changing fire and drought conditions. We examine future simulated streamflow within the context of an operational model framework to consider the impacts on water operators and managers who rely upon the timely and continual delivery of streamflow. We focus on results for a large case study basin within the CRB—the San Juan River—showing future scenarios where this ecosystem is pushed towards the extremes. Our findings illustrate that landscape change in the CRB cause delayed snowmelt and increased evapotranspiration from shrublands, which leads to increases in the frequency and magnitude of both droughts and floods within disturbed systems. By 2080, coupled climate and landscape change produces a dramatically altered hydrograph resulting in larger peak flows, reduced lower flows, and lower overall streamflow. Operationally, this results in increased future water delivery challenges and lower reservoir storages driven by changes in the headwater basins. Ultimately, our work shows that the already-stressed CRB ecosystem could, in the future, be pushed over a tipping point, significantly impacting the basin's ability to reliably supply water for food, energy, and urban uses.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5273B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5273B"><span>River salinity on a mega-delta, an unstructured grid model approach.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bricheno, Lucy; Saiful Islam, Akm; Wolf, Judith</p> <p>2014-05-01</p> <p>With an average freshwater discharge of around 40,000 m3/s the BGM (Brahmaputra Ganges and Meghna) river system has the third largest discharge worldwide. The BGM river delta is a low-lying fertile area covering over 100,000 km2 mainly in India and Bangladesh. Approximately two-thirds of the Bangladesh people work in agriculture and these local livelihoods depend on freshwater sources directly linked to river salinity. The finite volume coastal ocean model (FVCOM) has been applied to the BGM delta in order to simulate river salinity under present and future climate conditions. Forced by a combination of regional climate model predictions, and a basin-wide river catchment model, the 3D baroclinic delta model can determine river salinity under the current climate, and make predictions for future wet and dry years. The river salinity demonstrates a strong seasonal and tidal cycle, making it important for the model to be able to capture a wide range of timescales. The unstructured mesh approach used in FVCOM is required to properly represent the delta's structure; a complex network of interconnected river channels. The model extends 250 km inland in order to capture the full extent of the tidal influence and grid resolutions of 10s of metres are required to represent narrow inland river channels. The use of FVCOM to simulate flows so far inland is a novel challenge, which also requires knowledge of the shape and cross-section of the river channels.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H33C1545C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H33C1545C"><span>Climate Change Impacts on River Temperature in the Southeastern United States: A Case Study of the Tennessee River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cheng, Y.; Niemeyer, R. J.; Mao, Y.; Yearsley, J. R.; Nijssen, B.</p> <p>2016-12-01</p> <p>In the coming decades, climate change and population growth are expected to affect water and energy supply as well as demand in the southeastern United States. Changes in temperature and precipitation impact river flow and stream temperature with implications for hydropower generation, industrial and municipal water supply, cooling for thermo-electric power plants, agricultural irrigation, ecosystem functions and flood control. At the same time, water and energy demand are expected to change in response to temperature increase, population growth and changing crop water requirements. As part of a multi-institution study of the food-energy-water nexus in the southeastern U.S., we are developing coupled hydrological and stream temperature models that will be linked to water resources, power systems and crop models at a later stage. Here we evaluate the ability of our system to simulate water supply and stream temperature in the Tennessee River Basin using the Variable Infiltration Capacity (VIC) macroscale hydrology model coupled to the River Basin Model (RBM), a 1-D semi-Lagrangian river temperature model, which has recently been expanded with a two-layer reservoir temperature model. Simulations with VIC-RBM were performed for the Tennessee River Basin at 1/8-degree spatial resolution and a temporal resolution of 1 day or less. Reservoir releases were prescribed based on historic operating rules. In future iterations, these releases will be modeled directly by a water resources model that incorporates flood control, and power and agricultural water demands. We compare simulated flows, as well as stream and reservoir temperatures with observed flows and temperatures throughout the basin. In preparation for later stages of the project, we also perform a set of climate change sensitivity experiments to evaluate how changes in climate may impact river and reservoir temperature.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HESSD..1014617I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HESSD..1014617I"><span>Trends and future challenges of water resources in the Tigris-Euphrates Rivers basin in Iraq</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Issa, I. E.; Al-Ansari, N. A.; Sherwany, G.; Knutsson, S.</p> <p>2013-12-01</p> <p>Iraq is one of the riparian countries within basins of Tigris-Euphrates Rivers in the Middle East region. The region is currently facing water shortage problems due to the increase of the demand and climate changes. In the present study, average monthly water flow measurements for 15 stream flow gaging stations within basins of these rivers in Iraq with population growth rate data in some of its part were used to evaluate the reality of the current situation and future challenges of water availability and demand in Iraq. The results showed that Iraq receives annually 70.29 km3 of water 45.4 and 25.52 km3 from River Tigris and Euphrates respectively. An amount of 18.04 km3 is supplied by its tributaries inside Iraq. The whole amount of water in the Euphrates Rivers comes outside the Iraqi borders. Annual decrease of the water inflow is 0.1335 km3 yr-1 for Tigris and 0.245 km3 yr-1 for Euphrates. This implies the annual percentage reduction of inflow rates for the two rivers is 0.294 and 0.960% respectively. Iraq consumes annually 88.89% (63.05 km3) of incoming water from the two rivers, where about 60.43 and 39.57% are from Rivers Tigris and Euphrates respectively. Water demand increases annually by 0.896 km3; of which 0.5271 and 0.475 km3 within Tigris and Euphrates basins respectively. The average water demand in 2020 will increase to 42.844 km3 yr-1 for Tigris basin and for Euphrates 29.225 km3 yr-1 (total 72.069 km3 yr-1), while water availability will decrease to 63.46 km3 yr-1. This means that the overall water shortage will be restricted to 8.61 km3.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H33H1707Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H33H1707Z"><span>The Development of a Real Time Surface Water Flow Model to Protect Public Water Intakes in West Virginia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zegre, N.; Strager, M.</p> <p>2015-12-01</p> <p>In January of 2014 West Virginia experienced a chemical spill upstream of a public water intake on the Elk River near Charleston, West Virginia that made the water unusable for 300,000 people for weeks. In response to this disaster, state officials enacted legislation to protect the future public water intake locations by requiring the delineation of zones of critical concern that extend a five hour travel time above the intakes. Each zone is defined by the travel time and buffered along the river mainstem and tributary locations to identify future potential threats to the water supply. While this approach helps to identify potential problems before they occur, the need existed to be able to respond to a spill with information regarding the real travel time of a spill to an intake with consideration of actual stream flow at the time of the spill. This study developed a real time surface flow model to protect the public water intakes using both regional and seasonal variables. Bayesian statistical inference enabled confidence levels to be placed on flow estimates and used to show the probability for the time steps as water approached an public water intake. The flow model has been incorporated into both a smartphone app and web-based tool for better emergency response and management of water resources throughout the state.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC41E..04A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC41E..04A"><span>Application of scenario-neutral methods to quantify impacts of climate change on water resources in East Africa</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ascott, M.; Macdonald, D.; Lapworth, D.; Tindimugaya, C.</p> <p>2017-12-01</p> <p>Quantification of the impact of climate change on water resources is essential for future resource planning. Unfortunately, climate change impact studies in African regions are often hindered by the extent in variability in future rainfall predictions, which also diverge from current drying trends. To overcome this limitation, "scenario-neutral" methods have been developed which stress a hydrological system using a wide range of climate futures to build a "climate response surface". We developed a hydrological model and scenario-neutral framework to quantify climate change impacts on river flows in the Katonga catchment, Uganda. Using the lumped catchment model GR4J, an acceptable calibration to historic daily flows (1966 - 2010, NSE = 0.69) was achieved. Using a delta change approach, we then systematically changed rainfall and PET inputs to develop response surfaces for key metrics, developed with Ugandan water resources planners (e.g. Q5, Q95). Scenarios from the CMIP5 models for 2030s and 2050s were then overlain on the response surface. The CMIP5 scenarios show consistent increases in temperature but large variability in rainfall increases, which results in substantial variability in increases in river flows. The developed response surface covers a wide range of climate futures beyond the CMIP5 projections, and can help water resources planners understand the sensitivity of water resource systems to future changes. When future climate scenarios are available, these can be directly overlain on the response surface without the need to re-run the hydrological model. Further work will consider using scenario-neutral approaches in more complex, semi-distributed models (e.g. SWAT), and will consider land use and socioeconomic change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017WRR....53.2278F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017WRR....53.2278F"><span>Flow resistance and hydraulic geometry in contrasting reaches of a bedrock channel</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ferguson, R. I.; Sharma, B. P.; Hardy, R. J.; Hodge, R. A.; Warburton, J.</p> <p>2017-03-01</p> <p>Assumptions about flow resistance in bedrock channels have to be made for mechanistic modeling of river incision, paleoflood estimation, flood routing, and river engineering. Field data on bedrock flow resistance are very limited and calculations generally use standard alluvial-river assumptions such as a fixed value of Manning's n. To help inform future work, we measured how depth, velocity, and flow resistance vary with discharge in four short reaches of a small bedrock channel, one with an entirely rock bed and the others with 20-70% sediment cover, and in the alluvial channel immediately upstream. As discharge and submergence increase in each of the partly or fully alluvial reaches there is a rapid increase in velocity and a strong decline in both n and the Darcy-Weisbach friction factor f. The bare-rock reach follows a similar trend from low to medium discharge but has increasing resistance at higher discharges because of the macroroughness of its rock walls. Flow resistance at a given discharge differs considerably between reaches and is highest where the partial sediment cover is coarsest and most extensive. Apart from the effect of rough rock walls, the flow resistance trends are qualitatively consistent with logarithmic and variable-power equations and with nondimensional hydraulic geometry, but quantitative agreement using sediment D84 as the roughness height is imperfect.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUSM.B33E..08A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUSM.B33E..08A"><span>Interspecific Relationships in Benthic Assemblages of a Large Lowland River : Co-existence or Competition as a Result of Habitat Characteristics</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akopian, M.; Usseglio-Polatera, P.</p> <p>2005-05-01</p> <p>Macrobenthic assemblages of the lower, regulated and canalized Marne River (France) are dominated by several "exotic", recently introduced species. Arrival, installation and spread of such alien species were certainly promoted by (1) the close connection between French and other European river systems (Rhine, Danube), (2) the modification of natural river flow and benthic habitats. Both habitat characteristics (e.g. granulometric composition, organic content) and corresponding benthic assemblage structure were analysed to identify the substrate affinity of major taxa in the lower Marne River. The main aim of the study was to evaluate the possible biotic interactions (i.e. competition for food and/or space) among dominant taxa as function of habitat features and to predict the future development of newly established species, already known as potential invaders: Corbicula fluminea (Bivalvia), Hypania invalida (Polychaeta), Chelicorophium curvispinum (Amphipoda), etc. Most of the newly established species, coming from the same biogeographical area ("invasional meltdown" hypothesis?), are eurytopic, with high fecundity and large food spectrum. First results demonstrated the co-existence of such species in the Marne River. But the future ecological importance of these organisms in benthic assemblages of the river depends on their present population size, population dynamics, and ability to colonize bottom substrates.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22840637','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22840637"><span>Development of a stream-aquifer numerical flow model to assess river water management under water scarcity in a Mediterranean basin.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mas-Pla, Josep; Font, Eva; Astui, Oihane; Menció, Anna; Rodríguez-Florit, Agustí; Folch, Albert; Brusi, David; Pérez-Paricio, Alfredo</p> <p>2012-12-01</p> <p>Stream flow, as a part of a basin hydrological cycle, will be sensible to water scarcity as a result of climate change. Stream vulnerability should then be evaluated as a key component of the basin water budget. Numerical flow modeling has been applied to an alluvial formation in a small mountain basin to evaluate the stream-aquifer relationship under these future scenarios. The Arbúcies River basin (116 km(2)) is located in the Catalan Inner Basins (NE Spain) and its lower reach, which is related to an alluvial aquifer, usually becomes dry during the summer period. This study seeks to determine the origin of such discharge losses whether from natural stream leakage and/or induced capture due to groundwater withdrawal. Our goal is also investigating how discharge variations from the basin headwaters, representing potential effects of climate change, may affect stream flow, aquifer recharge, and finally environmental preservation and human supply. A numerical flow model of the alluvial aquifer, based on MODFLOW and especially in the STREAM routine, reproduced the flow system after the usual calibration. Results indicate that, in the average, stream flow provides more than 50% of the water inputs to the alluvial aquifer, being responsible for the amount of stored water resources and for satisfying groundwater exploitation for human needs. Detailed simulations using daily time-steps permit setting threshold values for the stream flow entering at the beginning of the studied area so surface discharge is maintained along the whole watercourse and ecological flow requirements are satisfied as well. The effects of predicted rainfall and temperature variations on the Arbúcies River alluvial aquifer water balance are also discussed from the outcomes of the simulations. Finally, model results indicate the relevance of headwater discharge management under future climate scenarios to preserve downstream hydrological processes. They also point out that small mountain basins could be self-sufficient units so long as the response of the main hydrological components to external forces that produce water scarcity, as climate change or human pressures, is appropriately considered in water resource planning. Copyright © 2012 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.water.usgs.gov/sir2004-5114/','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/sir2004-5114/"><span>Simulation of ground-water flow and evaluation of water-management alternatives in the Assabet River Basin, Eastern Massachusetts</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>DeSimone, Leslie A.</p> <p>2004-01-01</p> <p>Water-supply withdrawals and wastewater disposal in the Assabet River Basin in eastern Massachusetts alter the flow and water quality in the basin. Wastewater discharges and stream-flow depletion from ground-water withdrawals adversely affect water quality in the Assabet River, especially during low-flow months (late summer) and in headwater areas. Streamflow depletion also contributes to loss of aquatic habitat in tributaries to the river. In 19972001, water-supply withdrawals averaged 9.9 million gallons per day (Mgal/d). Wastewater discharges to the Assabet River averaged 11 Mgal/d and included about 5.4 Mgal/d that originated from sources outside of the basin. The effects of current (2004) and future withdrawals and discharges on water resources in the basin were investigated in this study. Steady-state and transient ground-water-flow models were developed, by using MODFLOW-2000, to simulate flow in the surficial glacial deposits and underlying crystalline bedrock in the basin. The transient model simulated the average annual cycle at dynamic equilibrium in monthly intervals. The models were calibrated to 19972001 conditions of water withdrawals, wastewater discharges, water levels, and nonstorm streamflow (base flow plus wastewater discharges). Total flow through the simulated hydrologic system averaged 195 Mgal/d annually. Recharge from precipitation and ground-water discharge to streams were the dominant inflow and outflow, respectively. Evapotranspiration of ground water from wetlands and non-wetland areas also were important losses from the hydrologic system. Water-supply withdrawals and infiltration to sewers averaged 5 and 1.3 percent, respectively, of total annual out-flows and were larger components (12 percent in September) of the hydrologic system during low-flow months. Water budgets for individual tributary and main stem subbasins identified areas, such as the Fort Meadow Brook and the Assabet Main Stem Upper subbasins, where flows resulting from anthropo-genic activities were relatively large percentages, compared to other subbasins, (more than 20 percent in September) of total out-flows. Wastewater flows in the Assabet River accounted for 55, 32, and 20 percent of total nonstorm streamflow (base flow plus wastewater discharge) out of the Assabet Main Stem Upper, Middle, and Lower subbasins, respectively, in an average September. The ground-water-flow models were used to evaluate water-management alternatives by simulating hypothetical scenarios of altered withdrawals and discharges. A scenario that included no water management quantified nonstorm stream-flows that would result without withdrawals, discharges, septic-system return flow, or consumptive use. Tributary flows in this scenario increased in most subbasins by 2 to 44 percent relative to 19972001 conditions. The increases resulted mostly from variable combinations of decreased withdrawals and decreased infiltration to sewers. Average annual nonstorm streamflow in the Assabet River decreased slightly in this scenario, by 2 to 3 percent annually, because gains in ground-water discharge were offset by the elimination of wastewater discharges. A second scenario quantified the effects of increasing withdrawals and discharges to currently permitted levels. In this simulation, average annual tributary flows decreased in most subbasins, by less than 1 to 10 percent relative to 19972001 conditions. In the Assabet River, flows increased slightly, 1 to 5 percent annually, and the percentage of wastewater in the river increased to 69, 42, and 27 percent of total nonstorm streamflow out of the Assabet Main Stem Upper, Middle, and Lower subbasins, respectively, in an average September. A third set of scenarios quantified the effects of ground-water discharge of wastewater at four hypothetical sites, while maintaining 19972000 wastewater discharges to the Assabet River. Wastewater, discharged at a constant rate that varied among sites from 0.3 to 1</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JHyd..264..230H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JHyd..264..230H"><span>Susceptibility of the Batoka Gorge hydroelectric scheme to climate change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harrison, Gareth P.; Whittington, H.(Bert) W.</p> <p>2002-07-01</p> <p>The continuing and increased use of renewable energy sources, including hydropower, is a key strategy to limit the extent of future climate change. Paradoxically, climate change itself may alter the availability of this natural resource, adversely affecting the financial viability of both existing and potential schemes. Here, a model is described that enables the assessment of the relationship between changes in climate and the viability, technical and financial, of hydro development. The planned Batoka Gorge scheme on the Zambezi River is used as a case study to validate the model and to predict the impact of climate change on river flows, electricity production and scheme financial performance. The model was found to perform well, given the inherent difficulties in the task, although there is concern regarding the ability of the hydrological model to reproduce the historic flow conditions of the upper Zambezi Basin. Simulations with climate change scenarios illustrate the sensitivity of the Batoka Gorge scheme to changes in climate. They suggest significant reductions in river flows, declining power production, reductions in electricity sales revenue and consequently an adverse impact on a range of investment measures.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC11B1146S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC11B1146S"><span>Changes in Hydrological Extremes and its Relation to Climate Variability in Mountainous Watershed: A Case Study from Gandaki River Basin, Nepal</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shrestha, N. S.; Dahal, P.</p> <p>2016-12-01</p> <p>Changes in the hydrological extreme are expected due to climate variability and are needed to assess at local and regional scales since these changes are not uniform over the globe. This study analyses the changes in intensity, frequency and persistence hydrological extreme in Gandaki River Basin (GRB) Nepal over past and future and its relation to climate variability. Hydrological data of 12 different hydrological stations covering all the sub basins of Gandaki River Basin were analyzed. At least 1 hydrological station in each sub basin to the maximum of 3 was taken into consideration for this study. Results show that hydrological extreme have increased in intensity, frequency and persistence over recent year and are predicted to increase in future (2030-2060). The time-series analysis revealed an increase in the magnitude, frequency and duration of flood and drought. The instantaneous maximum flow, flood events and duration of flood events are found to have increasing trend. The minimum discharge was observed to be decreasing which entails that the water availability in the driest time is decreasing. Trend analysis of seasonal flow revealed an increase in monsoon flows and decreasing in post monsoon. Changes in climate variability over the same period shows higher anomalies in both temperature and precipitation in recent decades (1990s and 2000s) compared to the baseline period (1970-2000). Model suggests an increasing trend in annual flows with the increase more pronounced in 2060s. Significant increase in extreme flows and subsequent decrease in dependable flows suggest increase in frequency of isolated extreme flows followed by prolonged dry spells. Data also showed that the mean temperature will be increasing from 1.9 0C to 3.1 0C and precipitation will be changing by -8% to +12% in 2031-2060 compared to the baseline period. For long-term planning and management of water resources, current trend and future change in the pattern of water availability should be analysed well in advance. Climate change with intensifying extreme events will likely have serious consequences on the hydrological changes. Therefore, this study would be useful in understanding how the hydrological regime has been changing with climate change in mountainous watershed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MAP...130..349B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MAP...130..349B"><span>River flow prediction using hybrid models of support vector regression with the wavelet transform, singular spectrum analysis and chaotic approach</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baydaroğlu, Özlem; Koçak, Kasım; Duran, Kemal</p> <p>2018-06-01</p> <p>Prediction of water amount that will enter the reservoirs in the following month is of vital importance especially for semi-arid countries like Turkey. Climate projections emphasize that water scarcity will be one of the serious problems in the future. This study presents a methodology for predicting river flow for the subsequent month based on the time series of observed monthly river flow with hybrid models of support vector regression (SVR). Monthly river flow over the period 1940-2012 observed for the Kızılırmak River in Turkey has been used for training the method, which then has been applied for predictions over a period of 3 years. SVR is a specific implementation of support vector machines (SVMs), which transforms the observed input data time series into a high-dimensional feature space (input matrix) by way of a kernel function and performs a linear regression in this space. SVR requires a special input matrix. The input matrix was produced by wavelet transforms (WT), singular spectrum analysis (SSA), and a chaotic approach (CA) applied to the input time series. WT convolutes the original time series into a series of wavelets, and SSA decomposes the time series into a trend, an oscillatory and a noise component by singular value decomposition. CA uses a phase space formed by trajectories, which represent the dynamics producing the time series. These three methods for producing the input matrix for the SVR proved successful, while the SVR-WT combination resulted in the highest coefficient of determination and the lowest mean absolute error.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28384361','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28384361"><span>Qualitative simulation of bathymetric changes due to reservoir sedimentation: A Japanese case study.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bilal, Ahmed; Dai, Wenhong; Larson, Magnus; Beebo, Qaid Naamo; Xie, Qiancheng</p> <p>2017-01-01</p> <p>Sediment-dynamics modeling is a useful tool for estimating a dam's lifespan and its cost-benefit analysis. Collecting real data for sediment-dynamics analysis from conventional field survey methods is both tedious and expensive. Therefore, for most rivers, the historical record of data is either missing or not very detailed. Available data and existing tools have much potential and may be used for qualitative prediction of future bathymetric change trend. This study shows that proxy approaches may be used to increase the spatiotemporal resolution of flow data, and hypothesize the river cross-sections and sediment data. Sediment-dynamics analysis of the reach of the Tenryu River upstream of Sakuma Dam in Japan was performed to predict its future bathymetric changes using a 1D numerical model (HEC-RAS). In this case study, only annually-averaged flow data and the river's longitudinal bed profile at 5-year intervals were available. Therefore, the other required data, including river cross-section and geometry and sediment inflow grain sizes, had to be hypothesized or assimilated indirectly. The model yielded a good qualitative agreement, with an R2 (coefficient of determination) of 0.8 for the observed and simulated bed profiles. A predictive simulation demonstrated that the useful life of the dam would end after the year 2035 (±5 years), which is in conformity with initial detailed estimates. The study indicates that a sediment-dynamic analysis can be performed even with a limited amount of data. However, such studies may only assess the qualitative trends of sediment dynamics.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2008/5132/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2008/5132/"><span>Simulated Effects of Year 2030 Water-Use and Land-Use Changes on Streamflow near the Interstate-495 Corridor, Assabet and Upper Charles River Basins, Eastern Massachusetts</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Carlson, Carl S.; Desimone, Leslie A.; Weiskel, Peter K.</p> <p>2008-01-01</p> <p>Continued population growth and land development for commercial, industrial, and residential uses have created concerns regarding the future supply of potable water and the quantity of ground water discharging to streams in the area of Interstate 495 in eastern Massachusetts. Two ground-water models developed in 2002-2004 for the Assabet and Upper Charles River Basins were used to simulate water supply and land-use scenarios relevant for the entire Interstate-495 corridor. Future population growth, water demands, and commercial and residential growth were projected for year 2030 by the Metropolitan Area Planning Council. To assess the effects of future development on subbasin streamflows, seven scenarios were simulated by using existing computer-based ground-water-flow models with the data projected for year 2030. The scenarios incorporate three categories of projected 2030 water- and land-use data: (1) 2030 water use, (2) 2030 land use, and (3) a combination of 2030 water use and 2030 land use. Hydrologic, land-use, and water-use data from 1997 through 2001 for the Assabet River Basin study and 1989 through 1998 for the Upper Charles River Basin study were used to represent current conditions - referred to as 'basecase' conditions - in each basin to which each 2030 scenario was compared. The effects of projected 2030 land- and water-use change on streamflows in the Assabet River Basin depended upon the time of year, the hydrologic position of the subbasin in the larger basin, and the relative areas of new commercial and residential development projected for a subbasin. Effects of water use and land use on streamflow were evaluated by comparing average monthly nonstorm streamflow (base flow) for March and September simulated by using the models. The greatest decreases in streamflow (up to 76 percent in one subbasin), compared to the basecase, occurred in September, when streamflows are naturally at their lowest level. By contrast, simulated March streamflows decreased less than 6.5 percent from basecase streamflows in all subbasins for all scenarios. The simulations showed similar effects in the Upper Charles River Basin, but increased water use contributed to decreased simulated streamflow in most subbasins. Simulated changes in March streamflows for 2030 in the Upper Charles River Basin were within +- 6 percent of the basecase for all scenarios and subbasins. Percentage decreases in simulated September streamflows for 2030 were greater than in March but less than the September decreases that resulted for some subbasins in the Assabet River Basin. Only two subbasins of the Upper Charles River Basin had projected decreases greater than 5 percent. In the Mill River subbasin, the decrease was 11 percent, and in the Mine Brook subbasin, 6.6 percent. Changes in water use and wastewater return flow generally were found to have the greatest effect in the summer months when streamflow and aquifer recharge rates are low and water use is high. September increases in main-stem streamflow of both basins were due mainly to increased discharge of treated effluent from wastewater-treatment facilities on the main-stem rivers. In the Assabet River Basin, wastewater-treatment-facility discharge became a smaller proportion of total streamflow with distance downstream. In contrast, wastewater-treatment facility discharge in the Upper Charles River Basin became a greater proportion of streamflow with distance downstream. The effects of sewer-line extension and low-impact development on streamflows in two different subbasins of the Assabet River Basin also were simulated. The result of extending sewer lines with a corresponding decrease in septic-system return flow caused September streamflows to decrease as much as 15 percent in the Fort Pond Brook subbasin. The effect of low-impact development was simulated in the Hop Brook subbasin in areas projected for commercial development. In this simulation, the greater the area where low-i</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2008/5024/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2008/5024/"><span>Effects of Habitat Characteristics and Water Quality on Macroinvertebrate Communities along the Neversink Riverin Southeastern New York, 1991-2001</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ernst, Anne G.; Baldigo, Barry P.; Schuler, George E.; Apse, Colin D.; Carter, James L.; Lester, Gary T.</p> <p>2008-01-01</p> <p>The Neversink River, in the Catskill Mountains of southeastern New York State, feeds the Neversink Reservoir, which diverts 85 percent of the river?s flow to New York City. Acidification of several headwater reaches has affected macroinvertebrate assemblages throughout the river system above the reservoir, and the alteration of flow conditions below the reservoir dam has affected macroinvertebrate assemblages for at least 10 kilometers downstream from the reservoir. In 1999, the U.S. Geological Survey, in cooperation with The Nature Conservancy, compiled data from 30 stream reaches to quantify the effects of acidification and of the reservoir on the structure and function of macroinvertebrate assemblages throughout the Neversink River. Acidic headwater reaches supported greater numbers of acid-tolerant chironomid taxa and fewer numbers of acid-sensitive Ephemeroptera and Trichoptera than neutral reaches, and fewer scraper individuals and more shredder individuals. The 14 reaches below the reservoir, with sharply decreased flows and altered flow patterns compared to reaches above the reservoir, supported more Chironomidae and fewer Ephemeroptera and Trichoptera than the upper reaches; they also had greater numbers of shredder individuals and fewer scraper and filterer individuals than reaches above the reservoir. Water-quality variables such as pH and aluminum concentration appear to have affected macroinvertebrate assemblages more strongly in the headwaters than below the reservoir, whereas physical-habitat variables such as mean channel width and water temperature have affected these assemblages more strongly downstream from the reservoir than in the headwaters. The water-quality changes due to acidification, combined with the decreased flows and lowered water temperatures below the reservoir, have disrupted downstream continuum of macroinvertebrate communities that would normally be observed from the headwaters to the mouth. The information presented herein provides a basis for further evaluation of the Neversink and similar river systems, and for assessment of the effectiveness of future conservation efforts.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25506909','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25506909"><span>Impacts of global change on the concentrations and dilution of combined sewer overflows in a drinking water source.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jalliffier-Verne, Isabelle; Leconte, Robert; Huaringa-Alvarez, Uriel; Madoux-Humery, Anne-Sophie; Galarneau, Martine; Servais, Pierre; Prévost, Michèle; Dorner, Sarah</p> <p>2015-03-01</p> <p>This study presents an analysis of climate change impacts on a large river located in Québec (Canada) used as a drinking water source. Combined sewer overflow (CSO) effluents are the primary source of fecal contamination of the river. An analysis of river flowrates was conducted using historical data and predicted flows from a future climate scenario. A spatio-temporal analysis of water quality trends with regard to fecal contamination was performed and the effects of changing flowrates on the dilution of fecal contaminants were analyzed. Along the river, there was a significant spatial trend for increasing fecal pollution downstream of CSO outfalls. Escherichia coli concentrations (upper 95th percentile) increased linearly from 2002 to 2012 at one drinking water treatment plant intake. Two critical periods in the current climate were identified for the drinking water intakes considering both potential contaminant loads and flowrates: local spring snowmelt that precedes river peak flow and extra-tropical storm events that occur during low flows. Regionally, climate change is expected to increase the intensity of the impacts of hydrological conditions on water quality in the studied basin. Based on climate projections, it is expected that spring snowmelt will occur earlier and extreme spring flowrates will increase and low flows will generally decrease. High and low flows are major factors related to the potential degradation of water quality of the river. However, the observed degradation of water quality over the past 10 years suggests that urban development and population growth may have played a greater role than climate. However, climate change impacts will likely be observed over a longer period. Source water protection plans should consider climate change impacts on the dilution of contaminants in addition to local land uses changes in order to maintain or improve water quality. Copyright © 2014 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2014/5233/pdf/sir2014-5233.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2014/5233/pdf/sir2014-5233.pdf"><span>Water quality of groundwater and stream base flow in the Marcellus Shale Gas Field of the Monongahela River Basin, West Virginia, 2011-12</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chambers, Douglas B.; Kozar, Mark D.; Messinger, Terence; Mulder, Michon L.; Pelak, Adam J.; White , Jeremy S.</p> <p>2015-01-01</p> <p>This study provides a baseline of water-quality conditions in the Monongahela River Basin in West Virginia during the early phases of development of the Marcellus Shale gas field. Although not all inclusive, the results of this study provide a set of reliable water-quality data against which future data sets can be compared and the effects of shale-gas development may be determined.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JHyd..520...75S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JHyd..520...75S"><span>Environmental flow assessments for transformed estuaries</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Tao; Zhang, Heyue; Yang, Zhifeng; Yang, Wei</p> <p>2015-01-01</p> <p>Here, we propose an approach to environmental flow assessment that considers spatial pattern variations in potential habitats affected by river discharges and tidal currents in estuaries. The approach comprises four steps: identifying and simulating the distributions of critical environmental factors for habitats of typical species in an estuary; mapping of suitable habitats based on spatial distributions of the Habitat Suitability Index (HSI) and adopting the habitat aggregation index to understand fragmentation of potential suitable habitats; defining variations in water requirements for a certain species using trade-off analysis for different protection objectives; and recommending environmental flows in the estuary considering the compatibility and conflict of freshwater requirements for different species. This approach was tested using a case study in the Yellow River Estuary. Recommended environmental flows were determined by incorporating the requirements of four types of species into the assessments. Greater variability in freshwater inflows could be incorporated into the recommended environmental flows considering the adaptation of potential suitable habitats with variations in the flow regime. Environmental flow allocations should be conducted in conjunction with land use conflict management in estuaries. Based on the results presented here, the proposed approach offers flexible assessment of environmental flow for aquatic ecosystems that may be subject to future change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999Geomo..31..229G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999Geomo..31..229G"><span>Fluvial geomorphology and river engineering: future roles utilizing a fluvial hydrosystems framework</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gilvear, David J.</p> <p>1999-12-01</p> <p>River engineering is coming under increasing public scrutiny given failures to prevent flood hazards and economic and environmental concerns. This paper reviews the contribution that fluvial geomorphology can make in the future to river engineering. In particular, it highlights the need for fluvial geomorphology to be an integral part in engineering projects, that is, to be integral to the planning, implementation, and post-project appraisal stages of engineering projects. It should be proactive rather than reactive. Areas in which geomorphologists will increasingly be able to complement engineers in river management include risk and environmental impact assessment, floodplain planning, river audits, determination of instream flow needs, river restoration, and design of ecologically acceptable channels and structures. There are four key contributions that fluvial geomorphology can make to the engineering profession with regard to river and floodplain management: to promote recognition of lateral, vertical, and downstream connectivity in the fluvial system and the inter-relationships between river planform, profile, and cross-section; to stress the importance of understanding fluvial history and chronology over a range of time scales, and recognizing the significance of both palaeo and active landforms and deposits as indicators of levels of landscape stability; to highlight the sensitivity of geomorphic systems to environmental disturbances and change, especially when close to geomorphic thresholds, and the dynamics of the natural systems; and to demonstrate the importance of landforms and processes in controlling and defining fluvial biotopes and to thus promote ecologically acceptable engineering. Challenges facing fluvial geomorphology include: gaining full acceptance by the engineering profession; widespread utilization of new technologies including GPS, GIS, image analysis of satellite and airborne remote sensing data, computer-based hydraulic modeling and geophysical techniques; dovetailing engineering approaches to the study of river channels which emphasize reach-scale flow resistance, shear stresses, and material strength with catchment scale geomorphic approaches, empirical predictions, bed and bank processes, landform evolution, and magnitude-frequency concepts; producing accepted river channel typologies; fundamental research aimed at producing more reliable deterministic equations for prediction of bed and bank stability and bedload transport; and collaboration with aquatic biologists to determine the role and importance of geomorphologically and hydraulically defined habitats.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26687086','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26687086"><span>Investigation of temporal change in glacial extent of Chitral watershed using Landsat data.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Naeem, Usman Ali; Shamim, Muhammad Ali; Ejaz, Naeem; Ur Rehman, Habib; Mustafa, Umer; Hashmi, Hashim Nisar; Ghumman, Abdul Razzaq</p> <p>2016-01-01</p> <p>Glaciers are also known as solid reservoirs, and in this regard, Pakistan is a blessed country to have enriched glaciers. The change in glacial extent becomes very crucial for rivers whose discharges are associated with glacier melt. Even a little change in the glacial extent may bring a significant change in the resulting river flows. Considering climate change scenarios, many researchers have predicted future flows in such catchments. But in almost all such studies, the reduction in the glaciers is not normally based on any rational. Therefore, research is needed in order to estimate how glaciers are actually behaving under the change of temperature and precipitations to better estimate the future flows. For this purpose, Chitral watershed was considered as the study area. The seasonal change in the snow extent was estimated by using MODIS data for various years that helped to identify the month with minimum glacial extent. With the help of remote sensing, unsupervised classification was performed to estimate the glacier area in Chitral watershed. The results show a definite receding trend with respect to time in the glaciers of the region for the past decade.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70026319','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70026319"><span>Flood plain and channel dynamics of the Quinault and Queets Rivers, Washington, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>O'Connor, J. E.; Jones, M.A.; Haluska, T.L.</p> <p>2003-01-01</p> <p>Observations from this study and previous studies on the Queets River show that channel and flood-plain dynamics and morphology are affected by interactions between flow, sediment, and standing and entrained wood, some of which likely involve time frames similar to 200–500-year flood-plain half-lives. On the upper Quinault River and Queets River, log jams promote bar growth and consequent channel shifting, short-distance avulsions, and meander cutoffs, resulting in mobile and wide active channels. On the lower Quinault River, large portions of the channel are stable and flow within vegetated flood plains. However, locally, channel-spanning log jams have caused channel avulsions within reaches that have been subsequently mobile for several decades. In all three reaches, log jams appear to be areas of conifer germination and growth that may later further influence channel and flood-plain conditions on long time scales by forming flood-plain areas resistant to channel migration and by providing key members of future log jams. Appreciation of these processes and dynamics and associated temporal and spatial scales is necessary to formulate effective long-term approaches to managing fluvial ecosystems in forested environments.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AdWR..113..249R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AdWR..113..249R"><span>Improving the ecohydrological and economic efficiency of Small Hydropower Plants with water diversion</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Razurel, Pierre; Gorla, Lorenzo; Tron, Stefania; Niayifar, Amin; Crouzy, Benoît; Perona, Paolo</p> <p>2018-03-01</p> <p>Water exploitation for energy production from Small Hydropower Plant (SHP) is increasing despite human pressure on freshwater already being very intense in several countries. Preserving natural rivers thus requires deeper understanding of the global (i.e., ecological and economic) efficiency of flow-diversion practice. In this work, we show that the global efficiency of SHP river intakes can be improved by non-proportional flow-redistribution policies. This innovative dynamic water allocation defines the fraction of water released to the river as a nonlinear function of river runoff. Three swiss SHP case studies are considered to systematically test the global performance of such policies, under both present and future hydroclimatic regimes. The environmental efficiency is plotted versus the economic efficiency showing that efficient solutions align along a (Pareto) frontier, which is entirely formed by non-proportional policies. On the contrary, other commonly used distribution policies generally lie below the Pareto frontier. This confirms the existence of better policies based on non-proportional redistribution, which should be considered in relation to implementation and operational costs. Our results recommend abandoning static (e.g., constant-minimal-flow) policies in favour of non-proportional dynamic ones towards a more sustainable use of the water resource, also considering changing hydroclimatic scenarios.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://fisheries.org/bookstore/all-titles/afs-symposia/54084p/','USGSPUBS'); return false;" href="http://fisheries.org/bookstore/all-titles/afs-symposia/54084p/"><span>The Mississippi River: A place for fish</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Schramm, Harold; Ickes, Brian; Chen, Yushun; Chapman, Duane C.; Jackson, John; Chen, Daqing; Li, Zhongjie; Kilgore, Jack; Phelps, Quinton E.; Eggleton, Michael</p> <p>2016-01-01</p> <p>The Mississippi River flows 3,734 km from its source at Lake Itasca, Minnesota to its outlet at the Gulf of Mexico. Along its course, it collects water from portions of two Canadian provinces and 41 % of the conterminous United States. Although greatly altered for navigation and flood control throughout much of its length, the Mississippi River remains an important fishery resource that provides habitat for 188 species of fishes and recreational and commercial fishing opportunities. The objectives of this chapter are to describe the contemporary fisheries habitat throughout the Mississippi River, identify how management to achieve human benefits influences the fishes and their habitats, and summarize efforts to conserve and enhance fish habitat. The 826-km headwater reach is entirely in Minnesota and remains largely unaltered. The reaches that extend 1,059 km from St. Anthony Falls, Minnesota to above the confluence with the Missouri River near St. Louis, Missouri have been altered by impoundment that has affected floodplain function, increased sedimentation of backwaters, and homogenized the formerly diverse aquatic habitats. After the confluence with the Missouri River, the Mississippi River flows freely for 1,849 km to the Gulf of Mexico. The alterations of the free-flowing reaches of greatest significance to the fisheries resource are reducing the duration and height of the flood pulse as a consequence of shortening the river channel, disconnection of the river from its historic and present floodplain, and loss of secondary channel-island complexes. Engineering features to improve commercial navigation have also added habitat and, when wisely manipulated, can be used to rehabilitate habitat. Some aspects of water quality have improved, but legacy chemicals and nutrient-laden inflows and sediments remain problems. Although true restoration in the sense of restoring all environmental conditions to an unaltered state is unlikely, the future value of the Mississippi River as a fisheries resource will depend on actively maintaining diverse and accessible aquatic habitats to support food webs and water quality suitable for fishes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016BGeo...13.2279F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016BGeo...13.2279F"><span>Optical properties and bioavailability of dissolved organic matter along a flow-path continuum from soil pore waters to the Kolyma River mainstem, East Siberia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frey, Karen E.; Sobczak, William V.; Mann, Paul J.; Holmes, Robert M.</p> <p>2016-04-01</p> <p>The Kolyma River in northeast Siberia is among the six largest Arctic rivers and drains a region underlain by vast deposits of Holocene-aged peat and Pleistocene-aged loess known as yedoma, most of which is currently stored in ice-rich permafrost throughout the region. These peat and yedoma deposits are important sources of dissolved organic matter (DOM) to inland waters that in turn play a significant role in the transport and ultimate remineralization of organic carbon to CO2 and CH4 along the terrestrial flow-path continuum. The turnover and fate of terrigenous DOM during offshore transport largely depends upon the composition and amount of carbon released to inland and coastal waters. Here, we measured the ultraviolet-visible optical properties of chromophoric DOM (CDOM) from a geographically extensive collection of waters spanning soil pore waters, streams, rivers, and the Kolyma River mainstem throughout a ˜ 250 km transect of the northern Kolyma River basin. During the period of study, CDOM absorption coefficients were found to be robust proxies for the concentration of DOM, whereas additional CDOM parameters such as spectral slopes (S) were found to be useful indicators of DOM quality along the flow path. In particular, the spectral slope ratio (SR) of CDOM demonstrated statistically significant differences between all four water types and tracked changes in the concentration of bioavailable DOC, suggesting that this parameter may be suitable for clearly discriminating shifts in organic matter characteristics among water types along the full flow-path continuum across this landscape. However, despite our observations of downstream shifts in DOM composition, we found a relatively constant proportion of DOC that was bioavailable ( ˜ 3-6 % of total DOC) regardless of relative water residence time along the flow path. This may be a consequence of two potential scenarios allowing for continual processing of organic material within the system, namely (a) aquatic microorganisms are acclimating to a downstream shift in DOM composition and/or (b) photodegradation is continually generating labile DOM for continued microbial processing of DOM along the flow-path continuum. Without such processes, we would otherwise expect to see a declining fraction of bioavailable DOC downstream with increasing residence time of water in the system. With ongoing and future permafrost degradation, peat and yedoma deposits throughout the northeast Siberian region will become more hydrologically active, providing greater amounts of DOM to fluvial networks and ultimately to the Arctic Ocean. The ability to rapidly and comprehensively monitor shifts in the quantity and quality of DOM across the landscape is therefore critical for understanding potential future feedbacks within the Arctic carbon cycle.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27251770','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27251770"><span>Validating alternative methodologies to estimate the regime of temporary rivers when flow data are unavailable.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gallart, F; Llorens, P; Latron, J; Cid, N; Rieradevall, M; Prat, N</p> <p>2016-09-15</p> <p>Hydrological data for assessing the regime of temporary rivers are often non-existent or scarce. The scarcity of flow data makes impossible to characterize the hydrological regime of temporary streams and, in consequence, to select the correct periods and methods to determine their ecological status. This is why the TREHS software is being developed, in the framework of the LIFE Trivers project. It will help managers to implement adequately the European Water Framework Directive in this kind of water body. TREHS, using the methodology described in Gallart et al. (2012), defines six transient 'aquatic states', based on hydrological conditions representing different mesohabitats, for a given reach at a particular moment. Because of its qualitative nature, this approach allows using alternative methodologies to assess the regime of temporary rivers when there are no observed flow data. These methods, based on interviews and high-resolution aerial photographs, were tested for estimating the aquatic regime of temporary rivers. All the gauging stations (13) belonging to the Catalan Internal Catchments (NE Spain) with recurrent zero-flow periods were selected to validate this methodology. On the one hand, non-structured interviews were conducted with inhabitants of villages near the gauging stations. On the other hand, the historical series of available orthophotographs were examined. Flow records measured at the gauging stations were used to validate the alternative methods. Flow permanence in the reaches was estimated reasonably by the interviews and adequately by aerial photographs, when compared with the values estimated using daily flows. The degree of seasonality was assessed only roughly by the interviews. The recurrence of disconnected pools was not detected by flow records but was estimated with some divergences by the two methods. The combination of the two alternative methods allows substituting or complementing flow records, to be updated in the future through monitoring by professionals and citizens. Copyright © 2016 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.2763T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.2763T"><span>Evaluating the effects of monthly river flow trends on Environmental Flow allocation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Torabi Haghighi, Ali; Klove, Bjorn</p> <p>2010-05-01</p> <p>The Natural river flow regime can be changed by the construction of hydraulic structures such as dams, hydropower plants, pump stations and so on. Due to the new river flow regime, some parts of water resources must be allocated to environmental flow (EF). There are more than 62 hydrological methods which have been proposed for calculating EF, although these methods don't have enough acceptability to be used in practical cases and The so other methods are preferred such as holistic,….. Most hydrological methods do not take basin physiography, climate, location of hydraulic structures, monthly river flow regime, historical trend of river (annually regime), purpose of hydraulic structures and so on, into consideration. In the present work, data from more than 180 rivers from Asia (71 rivers and 16 countries), Europe (79 Rivers and 23 countries), Americas (23 rivers and 10 countries) and Africa (12 rivers and 6 countries) were used to assess EF. The rivers were divided into 5 main groups of regular permanent rivers, semi regular permanent rivers, irregular permanent rivers, seasonal rivers and dry rivers, for each groups EF calculated by some hydrological methods and compared with the natural flow regime. The results showed that besides the amount of EF, the monthly distribution of flow is very important and should be considered in reservoir operation. In seasonal rivers and dry rivers, hydraulic structure construction can be useful for conserving aquatic ecosystems</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.H13F1414R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.H13F1414R"><span>Environmental Flow Assessments in the McKenzie and Santiam River Basins, Oregon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Risley, J. C.; Bach, L.; Budai, C.; Duffy, K.</p> <p>2012-12-01</p> <p>The McKenzie and Santiam Rivers are tributaries of the Willamette River in northwestern Oregon, draining areas of 3,370 and 4,690 square kilometers, respectively. The river basins are heavily forested and contain streams that historically provided critical habit for salmonid rearing, salmonid spawning, and bull trout. In the 1950s and 1960s, hydropower and flood control dams were constructed in both basins. In 2008, the U.S. Geological Survey (USGS), in cooperation with The Nature Conservancy (TNC) and the U.S. Army Corps of Engineers (Corps), began assessing the impacts of dam regulation in the two basins on streamflow, geomorphic, and ecological processes (Risley et. al., 2010; 2012). The baseline assessments were made under the auspices of the Sustainable Rivers Project (SRP), formed in 2002 by TNC and the Corps. SRP is a nation-wide partnership aimed at developing, implementing, and refining environmental flows downstream of dams. Environmental flows can be defined as the streamflow needed to sustain ecosystems while continuing to meet human needs. Determining environmental flows is an iterative collective process involving stakeholders, workshops, bio-monitoring, and follow-up assessments. The dams on the McKenzie and Santiam Rivers have decreased the frequency and magnitude of floods and increased the magnitude of low flows. In the Santiam River study reaches, for example, annual 1-day maximum streamflows decreased by 46-percent on average because of regulated streamflow conditions. Annual 7-day minimum flows in six of the seven study reaches increased by 146 percent on average. On a seasonal basis, median monthly streamflows in both river basins decreased from February to May and increased from September to January. However, the magnitude of these impacts usually decreased farther downstream from the dams because of the cumulative inflow from unregulated tributaries and groundwater discharge below the dams. In addition to streamflow assessments, the USGS studies included a geomorphic and ecological characterization of both rivers using reach characterization, historical channel mapping, aerial photography, and specific gage analysis methods. Decreased flooding and decreased sediment supply resulting from the dams likely contributed to a decrease in gravel bars, which are critical to salmonid spawning. Secondary channel features and sinuosity also decreased. However, other anthropogenic factors, such as bank stabilization revetments, land filling, and channel dredging, have also impacted channel morphology in both basins. Exemplar native terrestrial and aquatic species of interest and used in developing environmental flows for both river basins include black cottonwood, red alder, bull trout, spring Chinook, Oregon chub, red-legged frogs, and western pond turtles. Suggestions for future bio-monitoring and investigations were also provided in the study reports. References: Risley, John, Wallick, J.R., Waite, Ian, and Stonewall, Adam, 2010, Development of an environmental flow framework for the McKenzie River basin, Oregon: U.S. Geological Survey Scientific Investigations Report 2010-5016, 94 p. Risley, J.C., Wallick, J.R., Mangano, J.F., and Jones, K.F., 2012, An environmental streamflow assessment for the Santiam River basin, Oregon: U.S. Geological Survey Open-File Report 2012-1133, 66 p.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.7964P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.7964P"><span>Restored river corridors: first results on the effects of flow variability on vegetation cuttings survival rate and related root architecture</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pasquale, N.; Perona, P.; Jiang, Z.; Burlando, P.</p> <p>2009-04-01</p> <p>Understanding and predicting the evolution of river alluvial bed forms toward a vegetated or a non-vegetated morphology have important implications for restored river corridors and the related ecosystem functioning (see also Schäppi et al, this session). Vegetation recruitment and growth on non-cohesive material of river corridors, such as gravel bars and islands of braided river, depend on the ability of roots to develop and anchor efficiently such to resist against flow erosion. In this work, we study the interannual morphological evolution of a gravel bar island, the survival rate and the growth of a number of plots with different density and orientation of transplanted cuttings (Salix Alba), the space and time dynamics of which depend on erosion and deposition processes due to floods. Our purpose is to identify island locations where the hydrodynamic conditions are more suitable for plants germination, growth and survival in relation to the river hydrograph statistics. This information is a first step to build a stochastic model able to predict the future evolution and progress of the restoration action of the investigated river reach. We focus at the main island of River Thur at Niederneunforn (Canton Thurgau, Switzerland), the restoration success of which is investigated from a mechanistic viewpoint in the research project "REstored CORridor Dynamics" (www.record.ethz.ch). Accordingly, we analyze two recent Digital Elevation Models (1 year difference), which were first corrected to account for the river bathymetry, and then we compare them in order to extract relevant interannual morphological changes. Using a two dimensional numerical hydrodynamic model we simulate several flow conditions ranging from the minimum recorded flow up to the one that completely inundates the island. Hence, we build inundation maps of the island that we associate to the frequency and the submergence duration of every area. We then correlate such results to the observed survival rate and the root characteristics of a sample of 1-year old transplanted cuttings. Despite limited in number, the investigated sample suggests that roots are shot from different points of the cuttings, which seem to reflect their location on the island and the direction of major resistance to flow erosion, also in agreement with the inundation maps.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://tigerprints.clemson.edu/scwrc/','USGSPUBS'); return false;" href="http://tigerprints.clemson.edu/scwrc/"><span>Optimally managing water resources in large river basins for an uncertain future</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Edwin A. Roehl, Jr.; Conrads, Paul</p> <p>2014-01-01</p> <p>Managers of large river basins face conflicting needs for water resources such as wildlife habitat, water supply, wastewater assimilative capacity, flood control, hydroelectricity, and recreation. The Savannah River Basin for example, has experienced three major droughts since 2000 that resulted in record low water levels in its reservoirs, impacting local economies for years. The Savannah River Basin’s coastal area contains municipal water intakes and the ecologically sensitive freshwater tidal marshes of the Savannah National Wildlife Refuge. The Port of Savannah is the fourth busiest in the United States, and modifications to the harbor have caused saltwater to migrate upstream, reducing the freshwater marsh’s acreage more than 50 percent since the 1970s. There is a planned deepening of the harbor that includes flow-alteration features to minimize further migration of salinity. The effectiveness of the flow-alteration features will only be known after they are constructed. One of the challenges of basin management is the optimization of water use through ongoing development, droughts, and climate change. This paper describes a model of the Savannah River Basin designed to continuously optimize regulated flow to meet prioritized objectives set by resource managers and stakeholders. The model was developed from historical data by using machine learning, making it more accurate and adaptable to changing conditions than traditional models. The model is coupled to an optimization routine that computes the daily flow needed to most efficiently meet the water-resource management objectives. The model and optimization routine are packaged in a decision support system that makes it easy for managers and stakeholders to use. Simulation results show that flow can be regulated to significantly reduce salinity intrusions in the Savannah National Wildlife Refuge while conserving more water in the reservoirs. A method for using the model to assess the effectiveness of the flow-alteration features after the deepening also is demonstrated</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Geomo.279..176N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Geomo.279..176N"><span>Large wood, sediment, and flow regimes: Their interactions and temporal changes caused by human impacts in Japan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakamura, Futoshi; Seo, Jung Il; Akasaka, Takumi; Swanson, Frederick J.</p> <p>2017-02-01</p> <p>Water, sediment, and large wood (LW) are the three key components of dynamic river-floodplain ecosystems. We examined variations in sediment and LW discharge with respect to precipitation, the presence of dams, land and river use change, and related channel incision and forest expansion on gravel bars and floodplains across Japan. The results indicated that unit sediment discharge and unit LW discharge were smaller in southern Japan where precipitation intensity is generally much greater. Effective precipitation, an index that takes current and antecedent precipitation into account, was a strong predictor of discharge in small watersheds, but not in larger watersheds. However, precipitation intensities related to unit sediment discharge in intermediate and large watersheds were smaller than those associated with unit LW discharge, which we attribute to differences in particle shape and size and also transport mechanisms. The relationship between river flow and discharge of sediment and LW lead us to posit that discharges of these components are supply limited in southern Japan and transport limited in northern Japan. The cross-sectional mean low-flow bed elevation of gravel-bed and sand-bed rivers in Japan decreased by 0.71 and 0.74 m on average, respectively, over the period 1960-2000. Forest expansion on bars and floodplains has been prominent since the 1990s, and trees apparently began to colonize gravel bars 10 to 20 years after riverbed degradation began. Forest recovery in headwater basins, dam construction, gravel mining, and channelization over the past half century are likely the dominant factors that significantly reduced downstream sediment delivery, thereby promoting channel incision and forest expansion. Changes in rivers and floodplains associated with channel incision and forest expansion alter the assemblages of aquatic and terrestrial organisms in riverine landscapes of Japan, and climate change may contribute to this change by intensified precipitation. Additionally, regime shifts of water, sediment, and LW may continue or they may reach a dynamic state of quasi-equilibrium in the future. Continued monitoring of these three components, taking into account their geographic variation, is critical for anticipating and managing future changes in river-floodplain systems in Japan and around the world.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H14D..04S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H14D..04S"><span>The Role of Forests in Regulating the River Flow Regime of Large Basins of the World</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salazar, J. F.; Villegas, J. C.; Mercado-Bettin, D. A.; Rodríguez, E.</p> <p>2016-12-01</p> <p>Many natural and social phenomena depend on river flow regimes that are being altered by global change. Understanding the mechanisms behind such alterations is crucial for predicting river flow regimes in a changing environment. Here we explore potential linkages between the presence of forests and the capacity of river basins for regulating river flows. Regulation is defined here as the capacity of river basins to attenuate the amplitude of the river flow regime, that is to reduce the difference between high and low flows. We first use scaling theory to show how scaling properties of observed river flows can be used to classify river basins as regulated or unregulated. This parsimonious classification is based on a physical interpretation of the scaling properties (particularly the scaling exponents) that is novel (most previous studies have focused on the interpretation of the scaling exponents for floods only), and widely-applicable to different basins (the only assumption is that river flows in a given river basin exhibit scaling properties through well-known power laws). Then we show how this scaling framework can be used to explore global-change-induced temporal variations in the regulation capacity of river basins. Finally, we propose a conceptual hypothesis (the "Forest reservoir concept") to explain how large-scale forests can exert important effects on the long-term water balance partitioning and regulation capacity of large basins of the world. Our quantitative results are based on data analysis (river flows and land cover features) from 22 large basins of the world, with emphasis in the Amazon river and its main tributaries. Collectively, our findings support the hypothesis that forest cover enhances the capacity of large river basins to maintain relatively high mean river flows, as well as to regulate (ameliorate) extreme river flows. Advancing towards this quantitative understanding of the relation between forest cover and river flow regimes is crucial for water management- and land cover-related decisions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H14D..04S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H14D..04S"><span>The Role of Forests in Regulating the River Flow Regime of Large Basins of the World</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salazar, J. F.; Villegas, J. C.; Mercado-Bettin, D. A.; Rodríguez, E.</p> <p>2017-12-01</p> <p>Many natural and social phenomena depend on river flow regimes that are being altered by global change. Understanding the mechanisms behind such alterations is crucial for predicting river flow regimes in a changing environment. Here we explore potential linkages between the presence of forests and the capacity of river basins for regulating river flows. Regulation is defined here as the capacity of river basins to attenuate the amplitude of the river flow regime, that is to reduce the difference between high and low flows. We first use scaling theory to show how scaling properties of observed river flows can be used to classify river basins as regulated or unregulated. This parsimonious classification is based on a physical interpretation of the scaling properties (particularly the scaling exponents) that is novel (most previous studies have focused on the interpretation of the scaling exponents for floods only), and widely-applicable to different basins (the only assumption is that river flows in a given river basin exhibit scaling properties through well-known power laws). Then we show how this scaling framework can be used to explore global-change-induced temporal variations in the regulation capacity of river basins. Finally, we propose a conceptual hypothesis (the "Forest reservoir concept") to explain how large-scale forests can exert important effects on the long-term water balance partitioning and regulation capacity of large basins of the world. Our quantitative results are based on data analysis (river flows and land cover features) from 22 large basins of the world, with emphasis in the Amazon river and its main tributaries. Collectively, our findings support the hypothesis that forest cover enhances the capacity of large river basins to maintain relatively high mean river flows, as well as to regulate (ameliorate) extreme river flows. Advancing towards this quantitative understanding of the relation between forest cover and river flow regimes is crucial for water management- and land cover-related decisions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://tigerprints.clemson.edu/scwrc/2014/2014policy/3/','USGSPUBS'); return false;" href="http://tigerprints.clemson.edu/scwrc/2014/2014policy/3/"><span>Optimally managing water resources in large river basins for an uncertain future</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Roehl, Edwin A.; Conrads, Paul</p> <p>2014-01-01</p> <p>One of the challenges of basin management is the optimization of water use through ongoing regional economic development, droughts, and climate change. This paper describes a model of the Savannah River Basin designed to continuously optimize regulated flow to meet prioritized objectives set by resource managers and stakeholders. The model was developed from historical data by using machine learning, making it more accurate and adaptable to changing conditions than traditional models. The model is coupled to an optimization routine that computes the daily flow needed to most efficiently meet the water-resource management objectives. The model and optimization routine are packaged in a decision support system that makes it easy for managers and stakeholders to use. Simulation results show that flow can be regulated to substantially reduce salinity intrusions in the Savannah National Wildlife Refuge while conserving more water in the reservoirs. A method for using the model to assess the effectiveness of the flow-alteration features after the deepening also is demonstrated.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2011/3012/fs2011-3012.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2011/3012/fs2011-3012.pdf"><span>Three Experimental High-Flow Releases from Glen Canyon Dam, Arizona-Effects on the Downstream Colorado River Ecosystem</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Melis, Theodore S.; Grams, Paul E.; Kennedy, Theodore A.; Ralston, Barbara E.; Robinson, Christopher T.; Schmidt, John C.; Schmit, Lara M.; Valdez, Richard A.; Wright, Scott A.</p> <p>2011-01-01</p> <p>Three high-flow experiments (HFEs) were conducted by the U.S. Department of the Interior at Glen Canyon Dam, Arizona, in March 1996, November 2004, and March 2008. Also known as artificial or controlled floods, these scheduled releases of water above the dam's powerplant capacity were designed to mimic pre-dam seasonal flooding on the Colorado River. The goal of the HFEs was to determine whether high flows could be used to benefit important downstream resources in Glen Canyon National Recreation Area and Grand Canyon National Park that have been affected by the existence and operation of Glen Canyon Dam. These downstream resources include native fish, particularly endangered humpback chub (Gila cypha), terrestrial and aquatic sandbar habitats, cultural sites, and recreational resources. This Fact Sheet summarizes HFE-related studies published since 1996 and outlines a possible strategy for implementing future HFEs.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wsp/1475q/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wsp/1475q/report.pdf"><span>Present and Future Water Supply for Mammoth Cave National Park, Kentucky</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cushman, R.V.; Krieger, R.A.; McCabe, John A.</p> <p>1965-01-01</p> <p>The increase in the number of visitors during the past several years at Mammoth Cave National Park has rendered the present water supply inadequate. Emergency measures were necessary during August 1962 to supplement the available supply. The Green River is the largest potential source of water supply for Mammoth Cave. The 30-year minimum daily discharge is 40 mgd (million gallons per day) . The chemical quality is now good, but in the past the river has been contaminated by oil-field-brine wastes. By mixing it with water from the existing supply, Green River water could be diluted to provide water of satisfactory quality in the event of future brine pollution. The Nolin River is the next largest potential source of water (minimum releases from Nolin Reservoir, 97-129 mgd). The quality is satisfactory, but use of this source would require a 8-mile pipeline. The present water supply comes from springs draining a perched aquifer in the Haney Limestone Member of the Golconda Formation on Flint Ridge. Chemical quality is excellent but the minimum observed flow of all the springs on Flint Ridge plus Bransford well was only 121,700 gpd (gallons per day). This supply is adequate for present needs but not for future requirements; it could be augmented with water from the Green River. Wet Prong Buffalo Creek is the best of several small-stream supplies in the vicinity of Mammoth Cave. Minimum flow of the creek is probably about 300,000 gpd and the quality is good. The supply is about 5 miles from Mammoth Cave. This supply also may be utilized for a future separate development in the northern part of the park. The maximum recorded yield of wells drilled into the basal ground water in the Ste. Genevieve and St. Louis Limestone is 36 gpm (gallons per minute). Larger supplies may be developed if a large underground stream is struck. Quality can be expected to be good unless the well is drilled too far below the basal water table and intercepts poorer quality water at a lower level. This source of supply might be used to augment the present supply, but locating the trunk conduits might be difficult. Water in alluvium adjacent to the Green River and perched water in the Big Clifty Sandstone Member of the Golconda Formation and Girkin Formation have little potential as a water supply.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC51D0825K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC51D0825K"><span>Economic Analysis of the Impacts of Climate-Induced Changes in River Flow on Hydropower and Fisheries in Himalayan region.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khadka Mishra, S.; Hayse, J.; Veselka, T.; Yan, E.; Kayastha, R. B.; McDonald, K.; Steiner, N.; Lagory, K.</p> <p>2017-12-01</p> <p>Climate-mediated changes in melting of snow and glaciers and in precipitation patterns are expected to significantly alter the water flow of rivers at various spatial and temporal scales. Hydropower generation and fisheries are likely to be impacted annually and over the century by the seasonal as well as long-term changes in hydrological conditions. In order to quantify the interactions between the drivers of climate change, the hydropower sector and the ecosystem we developed an integrated assessment framework that links climate models with process-based bio-physical and economic models. This framework was applied to estimate the impacts of changes in snow and glacier melt on the stream flow of the Trishuli River of the High Mountain Asia Region. Remotely-sensed data and derived products, as well as in-situ data, were used to quantify the changes in snow and glacier melt. The hydrological model was calibrated and validated for stream flows at various points in the Trishuli river in order to forecast conditions at the location of a stream gauge station upstream of the Trishuli hydropower plant. The flow of Trishuli River was projected to increase in spring and decrease in summer over the period of 2020-2100 under RCP 8.5 and RCP 4.5 scenarios as compared to respective mean seasonal discharge observed over 1981-2014. The simulated future annual mean stream flow would increase by 0.6 m3/s under RCP 8.5 scenario but slightly decrease under RCP 4.5. The Argonne Hydropower Energy and Economic toolkit was used to estimate and forecast electricity generation at the Trishuli power plant under various flow conditions and upgraded infrastructure. The increased spring flow is expected to increase dry-season electricity generation by 18% under RCP 8.5 in comparison to RCP 4.5. A fishery suitability model developed for the basin indicated that fishery suitability in the Trishuli River would be greater than 70% of optimal, even during dry months under both RCP 4.5 and RCP 8.5. The estimated economic value (preliminary result) of electricity generated from the Trishuli hydropower plant under RCP 4.5 and RCP 8.5 were projected to be 3.7% to 7.5% higher for the month of March while for the months of April and May the values were1.5% to 9.4% lower.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AdG....37...27G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AdG....37...27G"><span>The Grain-size Patchiness of Braided Gravel-Bed Streams - example of the Urumqi River (northeast Tian Shan, China)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guerit, L.; Barrier, L.; Narteau, C.; Métivier, F.; Liu, Y.; Lajeunesse, E.; Gayer, E.; Meunier, P.; Malverti, L.; Ye, B.</p> <p>2014-02-01</p> <p>In gravel-bed rivers, sediments are often sorted into patches of different grain-sizes, but in braided streams, the link between this sorting and the channel morpho-sedimentary elements is still unclear. In this study, the size of the bed sediment in the shallow braided gravel-bed Urumqi River is characterized by surface-count and volumetric sampling methods. Three morpho-sedimentary elements are identified in the active threads of the river: chutes at flow constrictions, which pass downstream to anabranches and bars at flow expansions. The surface and surface-layer grain-size distributions of these three elements show that they correspond to only two kinds of grain-size patches: (1) coarse-grained chutes, coarser than the bulk river bed, and (2) finer-grained anabranches and bars, consistent with the bulk river bed. In cross-section, the chute patches are composed of one coarse-grained top layer, which can be interpreted as a local armour layer overlying finer deposits. In contrast, the grain size of the bar-anabranch patches is finer and much more homogeneous in depth than the chute patches. Those patches, which are features of lateral and vertical sorting associated to the transport dynamics that build braided patterns, may be typical of active threads in shallow gravel-bed rivers and should be considered in future works on sorting processes and their geomorphologic and stratigraphic results.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://irma.nps.gov/DataStore/DownloadFile/600930','USGSPUBS'); return false;" href="https://irma.nps.gov/DataStore/DownloadFile/600930"><span>River flow and riparian vegetation dynamics - implications for management of the Yampa River through Dinosaur National Monument</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Scott, Michael L; Friedman, Jonathan M.</p> <p>2018-01-01</p> <p>This report addresses the relation between flow of the Yampa River and occurrence of herbaceous and woody riparian vegetation in Dinosaur National Monument (DINO) with the goal of informing management decisions related to potential future water development. The Yampa River in DINO flows through diverse valley settings, from the relatively broad restricted meanders of Deerlodge Park to narrower canyons, including debris fan-affected reaches in the upper Yampa Canyon and entrenched meanders in Harding Hole and Laddie Park. Analysis of occurrence of all plant species measured in 1470 quadrats by multiple authors over the last 24 years shows that riparian vegetation along the Yampa River is strongly related to valley setting and geomorphic surfaces, defined here as active channel, active floodplain, inactive floodplain, and upland. Principal Coordinates Ordination arrayed quadrats and species along gradients of overall cover and moisture availability, from upland and inactive floodplain quadrats and associated xeric species like western wheat grass (Pascopyrum smithii), cheatgrass (Bromus tectorum), and saltgrass (Distichlis spicata) to active channel and active floodplain quadrats supporting more mesic species including sandbar willow (Salix exigua), wild licorice (Glycyrrhiza lepidota), and cordgrass (Spartina spp.). Indicator species analysis identified plants strongly correlated with geomorphic surfaces. These species indicate state changes in geomorphic surfaces, such as the conversion of active channel to floodplain during channel narrowing. The dominant woody riparian species along the Yampa River are invasive tamarisk (Tamarix ramosissima), and native Fremont cottonwood (Populus deltoides ssp. wislizenii), box elder (Acer negundo L. var. interius), and sandbar willow (Salix exigua). These species differ in tolerance of drought, salinity, inundation, flood disturbance and shade, and in seed size, timing of seed dispersal and ability to form root sprouts. These physiological and ecological differences interact with flow variation and geomorphic setting, resulting in differential patterns of occurrence. For example, in park settings cottonwood is far more abundant than box elder, while the reverse is true in canyons. Synthesis of existing knowledge from the Yampa and Green rivers and elsewhere suggests that the following flow-vegetation relations can be used to assess effects of future flow alterations in the Yampa River.High variability in flow within and between years removes vegetation through erosion, extended inundation and desiccation, creating the broad, open surfaces in and near the channel that are characteristic of lightly regulated rivers in western North America. This flow variability provides opportunities for establishment of disturbance-dependent riparian species.Flow regulation that results in lower peak flows and higher low flows allows proliferation of woody riparian vegetation, mostly tamarisk in canyon reaches, but both tamarisk and cottonwood in parks. Denser near-channel vegetation promotes sediment deposition leading to channel narrowing. Decreasing flow variability also increases area of species associated with extremely high and low inundation durations relative to species associated with moderate inundation duration. In addition, such flow regulation decreases occurrence of species tolerant of fluvial disturbance, while increasing occurrence of species tolerant of extended inundation.Over the long term, establishment of cottonwood and tamarisk requires disturbance by large floods, which provides openings for new individuals. At the annual time scale, establishment can occur in any year or location that provides a moist, open surface free from frequent future disturbance. In canyons, where channel movement is limited, low surfaces are too frequently disturbed for long-term survival of cottonwood, and establishment requirements are generally met only in years of moderate to high peak flows. In park settings cottonwood establishment may also occur in years of low peak flows where survival is promoted by movement of the channel away from the seedling.Peak flows early in the growing season promote establishment of cottonwood and sandbar willow seedlings relative to those of tamarisk. This is because cottonwood and willow seed release occurs early in the summer, while that of tamarisk occurs later. Late season seed release of tamarisk allows it to establish lower on the floodplain than cottonwood.Because of its shade tolerance and the energy stored in its large seeds, box elder can become established beneath existing vegetation, an ability not shared by cottonwood, tamarisk or willow. Although box elder does not require flood disturbance, it does take advantage of soil moisture from floods, which allow this species to become established high above the channel.Decreases in flow peaks, volumes or base flows decrease growth and survival of cottonwood relative to drought-tolerant tamarisk. Storing water from the spring peak in a reservoir for release after the April-July cottonwood growth window may also decrease growth and survival of cottonwood relative to tamarisk. Decreases in peak flows decrease floodplain inundation, which can reduce growth of floodplain species by preventing recharge of the floodplain aquifer.Two or more years in a row with similar flows promote establishment of woody vegetation. Subsequent sediment deposition around this vegetation, especially if the vegetation is tamarisk, results in channel narrowing and simplification.Rapid declines in the descending limb of the hydrograph kill riparian woody seedlings by desiccation. Fluctuations in the descending limb can kill seedlings by desiccation and inundation. Thus rapid declines and fluctuations would be counterproductive following early-season peaks prescribed to promote cottonwood, but would be consistent with the goal of preventing tamarisk establishment following a late-season peak.The tendency of regulated flows to keep returning to a small number of fixed discharge values (such as power plant capacity or a fixed minimum flow) can cause unnaturally sharp banding of geomorphic surfaces, topography and vegetation that is not necessarily erased by large flood peaks.Changes in sediment load relative to transport capacity may promote channel change especially in alluvial settings. For example, decreases in sediment input from the Little Snake River Basin since 1960 (or earlier) could be associated with channel narrowing and temporary increases in establishment of both cottonwood and tamarisk along the Yampa River.Increases in salinity of water or soil promote tamarisk over the native woody species. Even if water salinity does not increase, floodplain soil salinity can be increased by decreasing the flushing caused by overbank flooding.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.H42B..07B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.H42B..07B"><span>Evaluating Snow Data Assimilation Framework for Streamflow Forecasting Applications Using Hindcast Verification</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barik, M. G.; Hogue, T. S.; Franz, K. J.; He, M.</p> <p>2012-12-01</p> <p>Snow water equivalent (SWE) estimation is a key factor in producing reliable streamflow simulations and forecasts in snow dominated areas. However, measuring or predicting SWE has significant uncertainty. Sequential data assimilation, which updates states using both observed and modeled data based on error estimation, has been shown to reduce streamflow simulation errors but has had limited testing for forecasting applications. In the current study, a snow data assimilation framework integrated with the National Weather System River Forecasting System (NWSRFS) is evaluated for use in ensemble streamflow prediction (ESP). Seasonal water supply ESP hindcasts are generated for the North Fork of the American River Basin (NFARB) in northern California. Parameter sets from the California Nevada River Forecast Center (CNRFC), the Differential Evolution Adaptive Metropolis (DREAM) algorithm and the Multistep Automated Calibration Scheme (MACS) are tested both with and without sequential data assimilation. The traditional ESP method considers uncertainty in future climate conditions using historical temperature and precipitation time series to generate future streamflow scenarios conditioned on the current basin state. We include data uncertainty analysis in the forecasting framework through the DREAM-based parameter set which is part of a recently developed Integrated Uncertainty and Ensemble-based data Assimilation framework (ICEA). Extensive verification of all tested approaches is undertaken using traditional forecast verification measures, including root mean square error (RMSE), Nash-Sutcliffe efficiency coefficient (NSE), volumetric bias, joint distribution, rank probability score (RPS), and discrimination and reliability plots. In comparison to the RFC parameters, the DREAM and MACS sets show significant improvement in volumetric bias in flow. Use of assimilation improves hindcasts of higher flows but does not significantly improve performance in the mid flow and low flow categories.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGC22B..06J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGC22B..06J"><span>Effects of Drought and Water Resource Management on Biophysical and Sociocultural Ecosystem Services in South-Central United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Julian, J.; Castro, A.; Vaughn, C.; Atkinson, C.</p> <p>2014-12-01</p> <p>South-Central United States is one of the fastest growing regions in the nation; however, it is experiencing water supply limitations. In response, multiple interests have focused on the Kiamichi River watershed in southeast Oklahoma as a future inter-basin water supply. The Kiamichi River provides many ecosystem services, including freshwater provision to 19 cities/towns, outdoor recreation hub for the South-Central U.S., cultural capital of the Choctaw Indian Nation, and a national biodiversity hotspot. With multiple recent stressors, these ecosystem services are highly threatened. Here we present how drought and water management have impacted these benefits over the past 20 years. First, we assessed the river's sensitivity to drought (which is cyclical) and water regulation (which has increased over the past three decades). Second, we analyzed how these hydrologic changes have impacted freshwater habitat, focusing on mussels because of their sensitivity to flow alterations and because they provide additional ecosystem services such as biofiltration, nutrient recycling/storage, and cultural resources. Third, we performed a sociocultural valuation for a suite of ecosystem services provided by the Kiamichi River watershed, including 505 interviews of five different ecosystem services beneficiary (ESB) groups. We obtained ESB perceptions on how ecosystem services changed with different flow conditions and water management strategies. Analyses revealed that increased regulation (fewer dam releases) has caused the Kiamichi River to have long no flow periods during droughts (e.g. 176 days with no flow in 2006). These long dry periods have been the main culprit for a 60% decline in mussel biomass over the past 20 years, and subsequent large losses in biofiltration and nutrient recycling. Interestingly, ESBs perceived similar losses of ecosystem services. Without being provided any information on flow, more than half of the ESBs believed that water supply, freshwater habitat, and water quality had all declined over the past decade. Overall, we found strong relationships among river flow, mussel abundance, and social perception of watershed services, suggesting that water management is key in maximizing the product of ecosystem services for all stakeholders.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1983/4182/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1983/4182/report.pdf"><span>Evaluation of future base-flow water-quality conditions in the Hillsborough River, Florida</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fernandez, Mario; Goetz, C.L.; Miller, J.E.</p> <p>1984-01-01</p> <p>A one-dimensional, steady-state, water-quality model was developed for a 30.0 mile reach of the Hillsborough River to evaluate water-quality conditions to be expected from future development. The model was calibrated and verified using data collected under critical base-flow conditions in April and December 1978. Dissolved organic nitrogen, nitrate nitrogen, and total and fecal coliforms were modeled for most of the study reach. Model results were used to evaluate the impacts of two typical housing developments on water-quality conditions in Tampa Reservoir. One development is located in the Cypress Creek basin and the other near the upper end of the study reach. Model results show development in the Hillsborough River basin may cause increased total and fecal coliform conditions. Simulated total coliforms at the Tampa water treatment plant for 1-, 3-, and 5-square-mile developments located in the Cypress Creek basin were 3,000, 5,400, and 8,300 colonies per 100 milliliters. Similar developments, however, located near the upper end of the study reach were 2,000, 3,600, and 5,100 colonies per 100 milliliters. Simulated fecal coliforms were 360, 700, and 100 and 180, 350, and 510 colonies per 100 milliliters, respectively. Other constituents modeled showed only minor increases in concentrations. (USGS)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ESASP.710E.109S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ESASP.710E.109S"><span>The Contribution of the Future SWOT Mission to Improve Simulations of River Stages and Stream-Aquifer Interactions at Regional Scale</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saleh, Firas; Filipo, Nicolas; Biancamaria, Sylvain; Habets, Florence; Rodriguez, Enersto; Mognard, Nelly</p> <p>2013-09-01</p> <p>The main objective of this study is to provide a realistic simulation of river stage in regional river networks in order to improve the quantification of stream-aquifer exchanges and better assess the associated aquifer responses that are often impacted by the magnitude and the frequency of the river stage fluctuations. This study extends the earlier work to improve the modeling of the Seine basin with a focus on simulating the hydrodynamics behavior of the Bassée alluvial wetland, a 120 km reach of the Seine River valley located south- east of Paris. The Bassée is of major importance for the drinking-water supply of Paris and surroundings, in addition to its particular hydrodynamic behavior due to the presence of a number of gravels. In this context, the understanding of stream-aquifer interactions is required for water quantity and quality preservation. A regional distributed process-based hydro(geo)logical model, Eau-Dyssée, is used. It aims at the integrated modeling of the hydrosystem to manage the various elements involved in the quantitative and qualitative aspects of water resources. Eau-Dyssée simulates pseudo 3D flow in aquifer systems solving the diffusivity equation with a finite difference numerical scheme. River flow is simulated with a Muskingum model. In addition to the in-stream discharge, a river stage estimate is needed to calculate the water exchange at the stream-aquifer interface using a conductance model. In this context, the future SWOT mission and its high-spatial resolution imagery can provide surface water level measurements at the regional scale that will permit to better characterize the Bassée complex hydro(geo)logical system and better assess soil water content. Moreover, the Bassée is considered as a potential target for the framework of the AirSWOT airborne campaign in France, 2013.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JAfES..45..395D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JAfES..45..395D"><span>Impact of rehabilitation of Assiut barrage, Nile River, on groundwater rise in urban areas</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dawoud, Mohamed A.; El Arabi, Nahed E.; Khater, Ahmed R.; van Wonderen, Jan</p> <p>2006-08-01</p> <p>To make optimum use of the most vital natural resource of Egypt, the River Nile water, a number of regulating structures (in the form of dams and barrages) for control and diversion of the river flow have been constructed in this river since the start of the 20th century. One of these barrages is the Assiut barrage which will require considerable repairs in the near future. The design of the rehabilitation of the barrage includes a headpond with water levels maintained at a level approximately 0.60 m higher than the highest water level in the headpond of the present barrage. This development will cause an increase of the seepage flow from the river towards the adjacent agricultural lands, Assiut Town and villages. The increased head pond level might cause a rise of the groundwater levels and impedance of drainage outflows. The drainage conditions may therefore be adversely affected in the so-called impacted areas which comprise floodplains on both sides of the Nile for about 70 km upstream of the future barrage. A rise in the groundwater table, particularly when high river levels impede drainage, may result in waterlogging and secondary salinization of the soil profile in agricultural areas and increase of groundwater into cellars beneath buildings in the urban areas. In addition, a rise in the groundwater table could have negative impact on existing sanitation facilities, in particular in the areas which are served with septic tanks. The impacts of increasing the headpond level were assessed using a three-dimensional groundwater model. The mechanisms of interactions between the Nile River and the underlying Quaternary aquifer system as they affect the recharge/discharge processes are comprehensively outlined. The model has been calibrated for steady state and transient conditions against historical data from observation wells. The mitigation measures for the groundwater rise in the urban areas have been tested using the calibrated mode.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.C41A0418B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.C41A0418B"><span>Glacial Meltwater Contirbutions to the Bow River, Alberta, Canada</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bash, E. A.; Marshall, S. J.; White, E. C.</p> <p>2009-12-01</p> <p>Assessment of glacial melt is critical for water resource management in areas which rely on glacier-fed rivers for agricultural and municipal uses. Changes in precipitation patterns coupled with current glacial retreat are altering the glacial contribution to river flow in areas such as the Andes of South America and the high ranges of Asia, as well as the Rockies of Western Canada. Alberta’s Bow River has its headwaters in the eastern slopes of the Canadian Rockies and contributes to the Nelson drainage system feeding into Hudson Bay. The Bow River basin contains several population centers, including the City of Calgary, and is heavily taxed for agricultural use. The combined effects of rapid glacial retreat in the Canadian Rockies, higher drought frequency, and increased demand are likely to heighten water stress in Southern Alberta. However, there has been little focus to date on the extent and importance of glacial meltwater in the Bow River. The Bow River contains 74.5 km2 of glacier ice, which amounts to only 0.29% of the basin. While this number is not high compared to some glacierized areas, Hopkinson and Young (1998) report that in dry years, glacier melt can provide up to 50% of late summer flows at a station in the upper reaches of the river system. We extend this work with an assessment of monthly and annual glacial contributions to the Bow River farther downstream in Calgary. Our analysis is based on mass balance, meteorological, and hydrological data that has been collected at the Haig Glacier since 2001. This data is used in conjunction with glacier coverage and hypsometric data for the remainder of the basin to estimate seasonal snow and glacial meltwater contributions to the Bow River from the glacierized fraction of the catchment. The results of this study show the percentage of total flow attributed to glacial melt to be highly variable. Glacier runoff contributes up to an order of magnitude more water to the Bow River per unit area of landscape, relative to the average areal contributions in the basin, accounting for 2-4% of the total flow in an average year, with glacier ice representing about 50% of this total. Future research is examining the impact of ongoing glacier retreat on these contributions and the seasonality of runoff.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1915631A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1915631A"><span>Hydropeaking in Nordic rivers - combined analysis from effects of changing climate conditions and energy demands to river regimes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ashraf, Faisal Bin; Marttila, Hannu; Torabi Haghighi, Ali; Alfredsen, Knut; Riml, Joakim; Kløve, Bjørn</p> <p>2017-04-01</p> <p>Increasing national and international demands for more flexible management of the energy resources with more non-storable renewables being used in adapting to the ongoing climate change will influence hydropower operations. Damming and regulation practices of river systems causes homogenization of long term river dynamics but also higher temporal sub-daily flow variations i.e. hydropeaking. In Nordic countries, many major rivers and lakes are regulated for hydropower purposes, which have caused considerable changes in river biotic, hydrologic and morphologic structures. Due to rapidly changing energy markets in the Nordic countries (deregulation of the power market and adding of renewable but intermittent sources of energy like, wind, solar, etc.) sub-daily flow conditions are under change within regulated river systems due to the increased demand on hydropower for providing balancing power. However, holistic analysis from changes in energy markets and its effect on sub-daily river regimes is lacking. This study analyzes the effects of hydropeaking on river regime in Finland, Sweden and Norway using long term high resolution data (15 minutes to hourly time interval) from 72 pristine and 136 regulated rivers with large spatial coverage across Fennoscandia. Since the sub-daily discharge variation is masked through the monthly or daily analyzes, in order to quantify these changes high resolution data is needed. In our study we will document, characterize and classify the impacts of sub-daily flow variation due to regulation and climatic variation on various river systems in Fennoscandia. Further, with increasing social demands for ecosystem services in regulated rivers, it is important to evaluate the new demand and update hydropower operation plan accordingly. We will analyse ecological response relationships along gradients of hydrological alteration for the biological communities, processes of river ecosystems and climate boundaries together with considering the new energy demands and consumptions in the Nordic energy market. For assessing sub-daily flow data various already available indices will be used which measure the magnitude of hydropeaking and temporal rate of discharge changes. For the impact quantification, the hydropeaking pressure will be calculated and set for each of the impact class. Also work will be done to formulate some new indices which will specifically quantify sub-daily change in the boreal rivers. We select representative case-studies, future scenarios and develop optimization methods to reduce impacts on aquatic ecosystems and maximizing the economic benefits from hydropower generation for stakeholders.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS53D..03J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS53D..03J"><span>Defining interactions of in-stream hydrokinetic devices in the Tanana River, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johnson, J.; Toniolo, H.; Seitz, A. C.; Schmid, J.; Duvoy, P.</p> <p>2012-12-01</p> <p>The acceptance, performance, and sustainability of operating in-stream hydrokinetic power generating devices in rivers depends on the impact of the river environment on hydrokinetic infrastructure as well as its impact on the river environment. The Alaska Hydrokinetic Energy Research Center (AHERC) conducts hydrokinetic "impact" and technology studies needed to support a sustainable hydrokinetic industry in Alaska. These include completed and ongoing baseline studies of river hydrodynamic conditions (river stage, discharge, current velocity, power, and turbulence; suspended and bed load sediment transport), ice, fish populations and behavior, surface and subsurface debris flows, and riverbed conditions. Technology and methods studies to minimize the effect of debris flows on deployed turbine system are in-progress to determine their effectiveness at reducing the probability of debris impact, diverting debris and their affect on available river power for conversion to electricity. An anchor point has been placed in the main flow just upstream of Main (Figure 1) to support projects and in preparation for future projects that are being planned to examine hydrokinetic turbine performance including power conversion efficiency, turbine drag and anchor chain loads, wake generation and effects on fish. Baseline fish studies indicate that hydrokinetic devices at the test site will have the most potential interactions with Pacific salmon smolts during their down-migration to the ocean in May and June. At the AHERC test site, the maximum turbulent kinetic energy (TKE) occurs just down stream from the major river bends (e.g., 000 and near the railroad bridge [upper center of the figure]) and over a deep hole at 440 (Figure 1), Minimum TKE occurs between main and 800. River current velocity measurements and simulations of river flow from 000 downstream past the railroad bridge indicate that the most stable current in the river reach is between Main and 800. The stable current and low TKE between Main and 800 indicate that this section of river may be the best site for deploying hydrokinetic devices. Woody debris exists as individual pieces or as large tangled masses on the surface, as full depth vertically oriented debris moving down river and as submerged debris posing a potential hazard to surface or subsurface deployed hydrokinetic devices. Submerged debris consists of logs, root balls, and small (mulch-like) debris. A surface debris diversion device has been tested and shown to be effective at diverting isolated debris and may reduce hazards for surface mounted devices.Figure 1. AHERC Tanana River test site at Nenana, AK.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.water.usgs.gov/wri034295/','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/wri034295/"><span>Relations among floodplain water levels, instream dissolved-oxygen conditions, and streamflow in the lower Roanoke River, North Carolina, 1997-2001</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bales, Jerad D.; Walters, Douglas A.</p> <p>2004-01-01</p> <p>The lower Roanoke River corridor in North Carolina contains a floodplain of national significance. Data from a network of 1 streamflow-measurement site, 13 river-stage sites, 13 floodplain water-level sites located along 4 transects, and 5 in situ water-quality monitoring sites were used to characterize temporal and spatial variations of floodplain and river water levels during 1997-2000 and to describe dissolved-oxygen conditions in the lower Roanoke River for the period 1998-2001. Major differences in the relation of floodplain inundation to flow occurred both among sites at a given transect and among transects. Several floodplain sites were inundated for the full range of flow conditions measured during the study. These included one site on the Big Swash transect (at about river kilometer 119); one site on the Broadneck Swamp transect (river kilometer 97), which was inundated 91 percent of the time during the study; one site on the Devils Gut transect (river kilometer 44), which was inundated throughout the study; and three sites on the Cow Swamp transect (near river kilometer 10). The relation of floodplain inundation depth to Roanoke River flow was highly variable among sites. There was no relation between flow and inundation depth at one of the Big Swash sites or at any of the four Cow Swamp sites. At two of the Big Swash transect sites, there was some relation between inundation depth and 10-day mean flow for flows greater than 700 cubic meters per second. A relatively strong relation between inundation depth and 10-day mean flow occurred at two of the Broadneck Swamp sites and, to a lesser degree, at two of the Devils Gut transect sites. There was much greater interannual variability in floodplain water levels, as represented by the difference between the maximum and minimum daily water level for a given calendar date during January-May and September-October than during the summer and late fall months. If data from this study are representative of long-term conditions, then this means that there is less uncertainty about what future floodplain water levels will be during June-August and November-December than during other months. Rates of ground-water decline, primarily due to evapotranspiration, were fairly similar at all sites, ranging from about 3 to 4 centimeters per day. For a 10-day mean flow of 300 cubic meters per second, an evaporative loss of 2 centimeters per day is equal to about 56 cubic meters per second. Evapotranspiration rates are much lower during the fall and winter months, so losses of river flow to floodplain processes likely are much lower during those months. The ground-water gradient at most sites was from the floodplain to the river, indicating a potential for ground-water movement into the river from the floodplain. At two of the Devils Gut sites, however, the water level often was higher in the river than in the floodplain when floodplain sites were not inundated. This indicates that there is a potential for river water to move as ground water from the river into the floodplain. It seems likely that this feature observed at the Devils Gut transect occurs elsewhere in the lower Roanoke River corridor. Dissolved-oxygen concentrations typically decrease with increasing distance from Roanoke Rapids Dam. During the 1998-2001 study period, the median dissolved-oxygen concentration at Halifax (river kilometer 187), the upstream-most station, was 8.4 milligrams per liter, and the median concentration at the downstream-most station (NC-45, bottom sensor; river kilometer 2.6) was 6.6 milligrams per liter. Several synoptic measurements of dissolved-oxygen concentration down the river identified the presence of a dissolved-oxygen sag in the vicinity of Halifax, with some recovery of concentrations between Halifax and about Scotland Neck at river kilometer 156. Data from the synoptic measurements also indicated that the greatest rate of dissolved-oxygen change with distance along the riv</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70141968','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70141968"><span>Large-scale dam removal on the Elwha River, Washington, USA: river channel and floodplain geomorphic change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>East, Amy E.; Pess, George R.; Bountry, Jennifer A.; Magirl, Christopher S.; Ritchie, Andrew C.; Logan, Joshua; Randle, Timothy J.; Mastin, Mark C.; Minear, Justin T.; Duda, Jeffrey J.; Liermann, Martin C.; McHenry, Michael L.; Beechie, Timothy J.; Shafroth, Patrick B.</p> <p>2015-01-01</p> <p>As 10.5 million t (7.1 million m3) of sediment was released from two former reservoirs, downstream dispersion of a sediment wave caused widespread bed aggradation of ~ 1 m (greater where pools filled), changed the river from pool–riffle to braided morphology, and decreased the slope of the lowermost river. The newly deposited sediment, which was finer than most of the pre-dam-removal bed, formed new bars (largely pebble, granule, and sand material), prompting aggradational channel avulsion that increased the channel braiding index by almost 50%. As a result of mainstem bed aggradation, floodplain channels received flow and accumulated new sediment even during low to moderate flow conditions. The river system showed a two- to tenfold greater geomorphic response to dam removal (in terms of bed elevation change magnitude) than it had to a 40-year flood event four years before dam removal. Two years after dam removal began, as the river had started to incise through deposits of the initial sediment wave, ~ 1.2 million t of new sediment (~ 10% of the amount released from the two reservoirs) was stored along 18 river km of the mainstem channel and 25 km of floodplain channels. The Elwha River thus was able to transport most of the released sediment to the river mouth. The geomorphic alterations and changing bed sediment grain size along the Elwha River have important ecological implications, affecting aquatic habitat structure, benthic fauna, salmonid fish spawning and rearing potential, and riparian vegetation. The response of the river to dam removal represents a unique opportunity to observe and quantify fundamental geomorphic processes associated with a massive sediment influx, and also provides important lessons for future river-restoration endeavors.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2011/3001/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2011/3001/"><span>How does a U.S. Geological Survey streamgage work?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lurry, Dee L.</p> <p>2010-01-01</p> <p>Information on the flow of rivers and streams is a vital national asset that safeguards lives, protects property, and ensures adequate water supplies for the future. The U.S. Geological Survey (USGS) operates a network of more than 9,000 streamgages nationwide with more than 500 in Texas.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1997/0089/pdf/of1997-0089.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1997/0089/pdf/of1997-0089.pdf"><span>Volcano hazards in the Mount Hood region, Oregon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Scott, W.E.; Pierson, T.C.; Schilling, S.P.; Costa, J.E.; Gardner, C.A.; Vallance, J.W.; Major, J.J.</p> <p>1997-01-01</p> <p>Mount Hood is a potentially active volcano close to rapidly growing communities and recreation areas. The most likely widespread and hazardous consequence of a future eruption will be for lahars (rapidly moving mudflows) to sweep down the entire length of the Sandy (including the Zigzag) and White River valleys. Lahars can be generated by hot volcanic flows that melt snow and ice or by landslides from the steep upper flanks of the volcano. Structures close to river channels are at greatest risk of being destroyed. The degree of hazard decreases as height above a channel increases, but large lahars can affect areas more than 30 vertical meters (100 vertical feet) above river beds. The probability of eruption-generated lahars affecting the Sandy and White River valleys is 1-in-15 to l-in-30 during the next 30 years, whereas the probability of extensive areas in the Hood River Valley being affected by lahars is about ten times less. The accompanying volcano-hazard-zonation map outlines areas potentially at risk and shows that some areas may be too close for a reasonable chance of escape or survival during an eruption. Future eruptions of Mount Hood could seriously disrupt transportation (air, river, and highway), some municipal water supplies, and hydroelectric power generation and transmission in northwest Oregon and southwest Washington.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H51G1350M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H51G1350M"><span>Quantifying the Contribution of Regional Aquifers to Stream Flow in the Upper Colorado River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Masbruch, M.; Dickinson, J.</p> <p>2017-12-01</p> <p>The growing population of the arid and semiarid southwestern U.S. relies on over-allocated surface water resources and poorly quantified groundwater resources. In the Upper Colorado River Basin, recent studies have found that about 50 percent of the surface water at U.S. Geological Survey (USGS) stream gages is derived from groundwater contributions as base flow. Prior USGS and other studies for the Colorado Plateau region have mainly examined groundwater and surface water as separate systems, and there has yet to be regional synthesis of groundwater availability in aquifers that contribute to surface water. A more physically based representation of groundwater flow could improve simulations of surface-water capture by groundwater pumping, and changes of groundwater discharge to surface water caused by possible shifts in the distribution, magnitude, and timing of recharge in the future. We seek to improve conceptual and numerical models of groundwater and surface-water interactions in the Colorado Plateau region as part of a USGS regional groundwater availability assessment. Numerical modeling is used to simulate and quantify the base flow from groundwater to the Colorado River and its major tributaries. Groundwater/surface-water interactions will be simulated using the USGS code GSFLOW, which couples the Precipitation Runoff Modeling System (PRMS) to the groundwater flow model MODFLOW. Initial results suggest that interactions between groundwater and surface water are important for projecting long-term changes in surface water budgets.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70175476','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70175476"><span>Reconstructions of Columbia River streamflow from tree-ring chronologies in the Pacific Northwest, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Littell, Jeremy; Pederson, Gregory T.; Gray, Stephen T.; Tjoelker, Michael; Hamlet, Alan F.; Woodhouse, Connie A.</p> <p>2016-01-01</p> <p>We developed Columbia River streamflow reconstructions using a network of existing, new, and updated tree-ring records sensitive to the main climatic factors governing discharge. Reconstruction quality is enhanced by incorporating tree-ring chronologies where high snowpack limits growth, which better represent the contribution of cool-season precipitation to flow than chronologies from trees positively sensitive to hydroclimate alone. The best performing reconstruction (back to 1609 CE) explains 59% of the historical variability and the longest reconstruction (back to 1502 CE) explains 52% of the variability. Droughts similar to the high-intensity, long-duration low flows observed during the 1920s and 1940s are rare, but occurred in the early 1500s and 1630s-1640s. The lowest Columbia flow events appear to be reflected in chronologies both positively and negatively related to streamflow, implying low snowpack and possibly low warm-season precipitation. High flows of magnitudes observed in the instrumental record appear to have been relatively common, and high flows from the 1680s to 1740s exceeded the magnitude and duration of observed wet periods in the late-19th and 20th Century. Comparisons between the Columbia River reconstructions and future projections of streamflow derived from global climate and hydrologic models show the potential for increased hydrologic variability, which could present challenges for managing water in the face of competing demands</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H11D1371J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H11D1371J"><span>Parameter Identification and Uncertainty Analysis for Visual MODFLOW based Groundwater Flow Model in a Small River Basin, Eastern India</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jena, S.</p> <p>2015-12-01</p> <p>The overexploitation of groundwater resulted in abandoning many shallow tube wells in the river Basin in Eastern India. For the sustainability of groundwater resources, basin-scale modelling of groundwater flow is essential for the efficient planning and management of the water resources. The main intent of this study is to develope a 3-D groundwater flow model of the study basin using the Visual MODFLOW package and successfully calibrate and validate it using 17 years of observed data. The sensitivity analysis was carried out to quantify the susceptibility of aquifer system to the river bank seepage, recharge from rainfall and agriculture practices, horizontal and vertical hydraulic conductivities, and specific yield. To quantify the impact of parameter uncertainties, Sequential Uncertainty Fitting Algorithm (SUFI-2) and Markov chain Monte Carlo (MCMC) techniques were implemented. Results from the two techniques were compared and the advantages and disadvantages were analysed. Nash-Sutcliffe coefficient (NSE) and coefficient of determination (R2) were adopted as two criteria during calibration and validation of the developed model. NSE and R2 values of groundwater flow model for calibration and validation periods were in acceptable range. Also, the MCMC technique was able to provide more reasonable results than SUFI-2. The calibrated and validated model will be useful to identify the aquifer properties, analyse the groundwater flow dynamics and the change in groundwater levels in future forecasts.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.H11C0681C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.H11C0681C"><span>Corps Water Management System (CWMS) Decision Support Modeling and Integration Use in the June 2007 Texas Floods</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Charley, W. J.; Luna, M.</p> <p>2007-12-01</p> <p>The U.S. Army Corps of Engineers Corps Water Management System (CWMS) is a comprehensive data acquisition and hydrologic modeling system for short-term decision support of water control operations in real time. It encompasses data collection, validation and transformation, data storage, visualization, real time model simulation for decision-making support, and data dissemination. CWMS uses an Oracle database and Sun Solaris workstations for data processes, storage and the execution of models, with a client application (the Control and Visualization Interface, or CAVI) that can run on a Windows PC. CWMS was used by the Lower Colorado River Authority (LCRA) to make hydrologic forecasts of flows on the Lower Colorado River and operate reservoirs during the June 2007 event in Texas. The LCRA receives real-time observed gridded spatial rainfall data from OneRain, Inc. that which is a result of adjusting NexRad rainfall data with precipitation gages. This data is used, along with future precipitation estimates, for hydrologic forecasting by the rainfall-runoff modeling program HEC-HMS. Forecasted flows from HEC-HMS and combined with observed flows and reservoir information to simulate LCRA's reservoir operations and help engineers make release decisions based on the results. The river hydraulics program, HEC-RAS, computes river stages and water surface profiles for the computed flow. An inundation boundary and depth map of water in the flood plain can be calculated from the HEC-RAS results using ArcInfo. By varying future precipitation and releases, engineers can evaluate different "What if?" scenarios. What was described as an "extraordinary cluster of thunderstorms" that stalled over Burnet and Llano counties in Texas on June 27, 2007, dropped 17 to 19 inches of rainfall over a 6-hour period. The storm was classified over a 500-year event and the resulting flow over some of the smaller tributaries as a 100-year or better. CWMS was used by LCRA for flood forecasting and reservoir operations. The models accurately forecasting the flows and allowed engineers to determine that only four floodgates needed to be opened for Mansfield dam, in the Chain of Highland lakes. CWMS also forecasted the peak of the flood well before it happened. Smaller rain storms continued for a period of weeks and CWMS was used throughout the event calculating lake levels, closing of gates along with a hydro-generation schedule.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.H23M..05K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.H23M..05K"><span>Climate change on the Colorado River: a method to search for robust management strategies</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Keefe, R.; Fischbach, J. R.</p> <p>2010-12-01</p> <p>The Colorado River is a principal source of water for the seven Basin States, providing approximately 16.5 maf per year to users in the southwestern United States and Mexico. Though the dynamics of the river ensure Upper Basin users a reliable supply of water, the three Lower Basin states (California, Nevada, and Arizona) are in danger of delivery interruptions as Upper Basin demand increases and climate change threatens to reduce future streamflows. In light of the recent drought and uncertain effects of climate change on Colorado River flows, we evaluate the performance of a suite of policies modeled after the shortage sharing agreement adopted in December 2007 by the Department of the Interior. We build on the current literature by using a simplified model of the Lower Colorado River to consider future streamflow scenarios given climate change uncertainty. We also generate different scenarios of parametric consumptive use growth in the Upper Basin and evaluate alternate management strategies in light of these uncertainties. Uncertainty associated with climate change is represented with a multi-model ensemble from the literature, using a nearest neighbor perturbation to increase the size of the ensemble. We use Robust Decision Making to compare near-term or long-term management strategies across an ensemble of plausible future scenarios with the goal of identifying one or more approaches that are robust to alternate assumptions about the future. This method entails using search algorithms to quantitatively identify vulnerabilities that may threaten a given strategy (including the current operating policy) and characterize key tradeoffs between strategies under different scenarios.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H33C1682M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H33C1682M"><span>Improving Simulations of Extreme Flows by Coupling a Physically-based Hydrologic Model with a Machine Learning Model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mohammed, K.; Islam, A. S.; Khan, M. J. U.; Das, M. K.</p> <p>2017-12-01</p> <p>With the large number of hydrologic models presently available along with the global weather and geographic datasets, streamflows of almost any river in the world can be easily modeled. And if a reasonable amount of observed data from that river is available, then simulations of high accuracy can sometimes be performed after calibrating the model parameters against those observed data through inverse modeling. Although such calibrated models can succeed in simulating the general trend or mean of the observed flows very well, more often than not they fail to adequately simulate the extreme flows. This causes difficulty in tasks such as generating reliable projections of future changes in extreme flows due to climate change, which is obviously an important task due to floods and droughts being closely connected to people's lives and livelihoods. We propose an approach where the outputs of a physically-based hydrologic model are used as an input to a machine learning model to try and better simulate the extreme flows. To demonstrate this offline-coupling approach, the Soil and Water Assessment Tool (SWAT) was selected as the physically-based hydrologic model, the Artificial Neural Network (ANN) as the machine learning model and the Ganges-Brahmaputra-Meghna (GBM) river system as the study area. The GBM river system, located in South Asia, is the third largest in the world in terms of freshwater generated and forms the largest delta in the world. The flows of the GBM rivers were simulated separately in order to test the performance of this proposed approach in accurately simulating the extreme flows generated by different basins that vary in size, climate, hydrology and anthropogenic intervention on stream networks. Results show that by post-processing the simulated flows of the SWAT models with ANN models, simulations of extreme flows can be significantly improved. The mean absolute errors in simulating annual maximum/minimum daily flows were minimized from 4967 cusecs to 1294 cusecs for Ganges, from 5695 cusecs to 2115 cusecs for Brahmaputra and from 689 cusecs to 321 cusecs for Meghna. Using this approach, simulations of hydrologic variables other than streamflow can also be improved given that a decent amount of observed data for that variable is available.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H43I1071R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H43I1071R"><span>A Statistical Weather-Driven Streamflow Model: Enabling future flow predictions in data-scarce headwater streams</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosner, A.; Letcher, B. H.; Vogel, R. M.</p> <p>2014-12-01</p> <p>Predicting streamflow in headwaters and over a broad spatial scale pose unique challenges due to limited data availability. Flow observation gages for headwaters streams are less common than for larger rivers, and gages with records lengths of ten year or more are even more scarce. Thus, there is a great need for estimating streamflows in ungaged or sparsely-gaged headwaters. Further, there is often insufficient basin information to develop rainfall-runoff models that could be used to predict future flows under various climate scenarios. Headwaters in the northeastern U.S. are of particular concern to aquatic biologists, as these stream serve as essential habitat for native coldwater fish. In order to understand fish response to past or future environmental drivers, estimates of seasonal streamflow are needed. While there is limited flow data, there is a wealth of data for historic weather conditions. Observed data has been modeled to interpolate a spatially continuous historic weather dataset. (Mauer et al 2002). We present a statistical model developed by pairing streamflow observations with precipitation and temperature information for the same and preceding time-steps. We demonstrate this model's use to predict flow metrics at the seasonal time-step. While not a physical model, this statistical model represents the weather drivers. Since this model can predict flows not directly tied to reference gages, we can generate flow estimates for historic as well as potential future conditions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS13B1225B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS13B1225B"><span>Energy Extraction from a Hypothetical MHK Array in a Section of the Mississippi River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barco, J.; James, S. C.; Roberts, J. D.; Jones, C. A.; Jepsen, R. A.</p> <p>2010-12-01</p> <p>The world is facing many challenges meeting the energy demands for the future. Growing populations and developing economies as well as increasing energy expenditures highlight the need for a spectrum of energy sources. Concerns about pollution and climate change have led to increased interest in all forms of renewable energy to stabilize or decrease consumption of fossil fuels. One promising renewable is marine and hydrokinetic (MHK) energy, which has the potential to make important contributions to energy portfolios of the future. However, a primary question remains: How much energy can be extracted from MHK devices in rivers and oceans without significant environmental effects? This study focuses on the potential energy extraction from different hypothetical MHK array configurations in a section of the Mississippi River located near to Scotlandville Bend, Louisiana. Bathymetry data, obtained from Free Flow Power Corporation (FFP) via the US Army Corps bathymetry survey library, were interpolated onto a DELFT3D curvilinear, orthogonal grid of the system using ArcGIS 9.3.1. Boundary conditions are constrained by the upstream and downstream river flow rates and gage heights obtained from USGS website. Acoustic Doppler Current Profiler (ADCP) measurements obtained from FFP are used for pre-array model validation. Energy extraction is simulated using momentum sinks recently coded into SNL-EFDC, which is an augmented version of US EPA’s Environmental Fluid Dynamics Code (EFDC). SNL-EFDC model includes a new module which considers energy removal by MHK devices and commensurate changes to the turbulent kinetic energy and turbulent kinetic energy dissipation rate. As expected, average velocities decrease downstream of each MHK device due to energy extraction and blunt-body form drag from the MHK support structures. Changes in the flow field can alter sediment transport dynamics around and downstream of an MHK array; various hypothetical scenarios are examined. This study highlights concepts that should be considered when planning, designing, and optimizing MHK devices arrays in riverine resources. Future efforts will focus on validating and verifying these sorts of models as data become available.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/819758','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/819758"><span>Echo Meadows Project Winter Artificial Recharge.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Ziari, Fred</p> <p>2002-12-19</p> <p>This report discusses the findings of the Echo Meadows Project (BPA Project 2001-015-00). The main purpose of this project is to artificially recharge an alluvial aquifer, WITH water from Umatilla River during the winter high flow period. In turn, this recharged aquifer will discharge an increased flow of cool groundwater back to the river, thereby improving Umatilla River water quality and temperature. A considerable side benefit is that the Umatilla River should improve as a habitat for migration, spanning, and rearing of anadromous and resident fish. The scope of this project is to provide critical baseline information about the Echomore » Meadows and the associated reach of the Umatilla River. Key elements of information that has been gathered include: (1) Annual and seasonal groundwater levels in the aquifer with an emphasis on the irrigation season, (2) Groundwater hydraulic properties, particularly hydraulic conductivity and specific yield, and (3) Groundwater and Umatilla River water quality including temperature, nutrients and other indicator parameters. One of the major purposes of this data gathering was to develop input to a groundwater model of the area. The purpose of the model is to estimate our ability to recharge this aquifer using water that is only available outside of the irrigation season (December through the end of February) and to estimate the timing of groundwater return flow back to the river. We have found through the data collection and modeling efforts that this reach of the river had historically returned as much as 45 cubic feet per second (cfs) of water to the Umatilla River during the summer and early fall. However, this return flow was reduced to as low as 10 cfs primarily due to reduced quantities of irrigation application, gain in irrigation efficiencies and increased groundwater pumping. Our modeling indicated that it is possible to restore these critical return flows using applied water outside of the irrigation season. We further found that this water can be timed to return to the river during the desired time of the year (summer to early fall). This is because the river stage, which remains relatively high until this time, drops during the irrigation season-thereby releasing the stored groundwater and increasing river flows. A significant side benefit is that these enhanced groundwater return flows will be clean and cold, particularly as compared to the Umatilla River. We also believe that this same type of application of water could be done and the resulting stream flows could be realized in other watersheds throughout the Pacific Northwest. This means that it is critical to compare the results from this baseline report to the full implementation of the project in the next phase. As previously stated, this report only discusses the results of data gathered during the baseline phase of this project. We have attempted to make the data that has been gathered accessible with the enclosed databases and spreadsheets. We provide computer links in this report to the databases so that interested parties can fully evaluate the data that has been gathered. However, we cannot emphasize too strongly that the real value of this project is to implement the phases to come, compare the results of these future phases to this baseline and develop the science and strategies to successfully implement this concept to other rivers in the Pacific Northwest. The results from our verified and calibrated groundwater model matches the observed groundwater data and trends collected during the baseline phase. The modeling results indicate that the return flows may increase to their historic values with the addition of 1 acre-ft/acre of recharge water to the groundwater system (about 9,600 acre-feet total). What this means is that through continued recharge project, you can double to quadruple the annual baseflow of the Umatilla River during the low summer and fall flow periods as compared to the present base-flow. The cool and high quality recharge water is a significant beneficial impact to the river system.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003WRR....39.1181T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003WRR....39.1181T"><span>Long-term flow forecasts based on climate and hydrologic modeling: Uruguay River basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tucci, Carlos Eduardo Morelli; Clarke, Robin Thomas; Collischonn, Walter; da Silva Dias, Pedro Leite; de Oliveira, Gilvan Sampaio</p> <p>2003-07-01</p> <p>This paper describes a procedure for predicting seasonal flow in the Rio Uruguay drainage basin (area 75,000 km2, lying in Brazilian territory), using sequences of future daily rainfall given by the global climate model (GCM) of the Brazilian agency for climate prediction (Centro de Previsão de Tempo e Clima, or CPTEC). Sequences of future daily rainfall given by this model were used as input to a rainfall-runoff model appropriate for large drainage basins. Forecasts of flow in the Rio Uruguay were made for the period 1995-2001 of the full record, which began in 1940. Analysis showed that GCM forecasts underestimated rainfall over almost all the basin, particularly in winter, although interannual variability in regional rainfall was reproduced relatively well. A statistical procedure was used to correct for the underestimation of rainfall. When the corrected rainfall sequences were transformed to flow by the hydrologic model, forecasts of flow in the Rio Uruguay basin were better than forecasts based on historic mean or median flows by 37% for monthly flows and by 54% for 3-monthly flows.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMEP32A..05N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMEP32A..05N"><span>The International River Interface Cooperative: Public Domain Software for River Flow and Morphodynamics (Invited)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nelson, J. M.; Shimizu, Y.; McDonald, R.; Takebayashi, H.</p> <p>2009-12-01</p> <p>The International River Interface Cooperative is an informal organization made up of academic faculty and government scientists with the goal of developing, distributing and providing education for a public-domain software interface for modeling river flow and morphodynamics. Formed in late 2007, the group released the first version of this interface (iRIC) in late 2009. iRIC includes models for two and three-dimensional flow, sediment transport, bed evolution, groundwater-surface water interaction, topographic data processing, and habitat assessment, as well as comprehensive data and model output visualization, mapping, and editing tools. All the tools in iRIC are specifically designed for use in river reaches and utilize common river data sets. The models are couched within a single graphical user interface so that a broad spectrum of models are available to users without learning new pre- and post-processing tools. The first version of iRIC was developed by combining the USGS public-domain Multi-Dimensional Surface Water Modeling System (MD_SWMS), developed at the USGS Geomorphology and Sediment Transport Laboratory in Golden, Colorado, with the public-domain river modeling code NAYS developed by the Universities of Hokkaido and Kyoto, Mizuho Corporation, and the Foundation of the River Disaster Prevention Research Institute in Sapporo, Japan. Since this initial effort, other Universities and Agencies have joined the group, and the interface has been expanded to allow users to integrate their own modeling code using Executable Markup Language (XML), which provides easy access and expandability to the iRIC software interface. In this presentation, the current components of iRIC are described and results from several practical modeling applications are presented to illustrate the capabilities and flexibility of the software. In addition, some future extensions to iRIC are demonstrated, including software for Lagrangian particle tracking and the prediction of bedform development and response to time-varying flows. Education and supporting documentation for iRIC, including detailed tutorials, are available at www.i-ric.org. The iRIC model codes, interface, and all supporting documentation are in the public domain.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70020362','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70020362"><span>Fluvial disturbance patches and cottonwood recruitment along the Upper Missouri River, Montana</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Auble, G.T.; Scott, M.L.</p> <p>1998-01-01</p> <p>The disturbance patches most suitable for seedling establishment of pioneer riparian trees are also subject to future disturbances that produce high seedling mortality. We are monitoring plains cottonwood seedling establishment and mortality along the Wild and Scenic reach of the Missouri River upstream of Fort Peck Reservoir, Montana at four sites subject to livestock grazing and four paired, ungrazed exclosures. New seedlings at these sites were largely restricted to surfaces inundated by spring and summer flows. Winter ice drives and livestock grazing are important mortality factors along the study reach. Livestock grazing reduced seedling densities, although the position of these seedlings in normal flow years means it is unlikely that they will survive future disturbance. Average values of the maximum density parameter of a Gaussian curve of seedling distribution along a hydraulic gradient of inundating discharge were 30 and 114 seedlings/m2 on ungrazed sites in 1996 and 1997, compared to 19 and 18 seedlings/m2 for grazed sites. Water-surface elevations produced by ice drives and damming in the severe winter of 1995-1996 corresponded to inundating discharges of 1,670 to 4,580 m3/s. No existing trees at the study sites occurred at inundating discharges below 1,625 m3/s. Seedlings established as a result of maximum summer flows of 827 and 1,201 m3/s in 1996 and 1997 were all below the elevation of the 10-year return flow of 1,495 m3/s. Recruitment of plains cottonwood trees along this reach of the Missouri River is strongly dependent on infrequent high flows that position moist, bare disturbed patches high enough for seedlings to establish and survive subsequent flooding and ice scour, in contrast to other reaches and streams where hydrogeomophic processes of channel meandering and narrowing produce different patterns of disturbance patches.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2014/5148/pdf/sir2014-5148.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2014/5148/pdf/sir2014-5148.pdf"><span>Documentation of a groundwater flow model (SJRRPGW) for the San Joaquin River Restoration Program study area, California</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Traum, Jonathan A.; Phillips, Steven P.; Bennett, George L.; Zamora, Celia; Metzger, Loren F.</p> <p>2014-01-01</p> <p>To better understand the potential effects of restoration flows on existing drainage problems, anticipated as a result of the San Joaquin River Restoration Program (SJRRP), the U.S. Geological Survey (USGS), in cooperation with the U.S. Bureau of Reclamation (Reclamation), developed a groundwater flow model (SJRRPGW) of the SJRRP study area that is within 5 miles of the San Joaquin River and adjacent bypass system from Friant Dam to the Merced River. The primary goal of the SJRRP is to reestablish the natural ecology of the river to a degree that restores salmon and other fish populations. Increased flows in the river, particularly during the spring salmon run, are a key component of the restoration effort. A potential consequence of these increased river flows is the exacerbation of existing irrigation drainage problems along a section of the river between Mendota and the confluence with the Merced River. Historically, this reach typically was underlain by a water table within 10 feet of the land surface, thus requiring careful irrigation management and (or) artificial drainage to maintain crop health. The SJRRPGW is designed to meet the short-term needs of the SJRRP; future versions of the model may incorporate potential enhancements, several of which are identified in this report. The SJRRPGW was constructed using the USGS groundwater flow model MODFLOW and was built on the framework of the USGS Central Valley Hydrologic Model (CVHM) within which the SJRRPGW model domain is embedded. The Farm Process (FMP2) was used to simulate the supply and demand components of irrigated agriculture. The Streamflow-Routing Package (SFR2) was used to simulate the streams and bypasses and their interaction with the aquifer system. The 1,300-square mile study area was subdivided into 0.25-mile by 0.25-mile cells. The sediment texture of the aquifer system, which was used to distribute hydraulic properties by model cell, was refined from that used in the CVHM to better represent the natural heterogeneity of aquifer-system materials within the model domain. In addition, the stream properties were updated from the CVHM to better simulate stream-aquifer interactions, and water-budget subregions were refined to better simulate agricultural water supply and demand. External boundary conditions were derived from the CVHM. The SJRRPGW was calibrated for April 1961 to September 2003 by using groundwater-level observations from 133 wells and streamflow observations from 19 streamgages. The model was calibrated using public-domain parameter estimation software (PEST) in a semi-automated manner. The simulated groundwater-level elevations and trends (including seasonal fluctuations) and surface-water flow magnitudes and trends reasonably matched observed data. The calibrated model is planned to be used to assess the potential effects of restoration flows on agricultural lands and the relative capabilities of proposed SJRRP actions to reduce these effects.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29059612','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29059612"><span>Export of microplastics from land to sea. A modelling approach.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Siegfried, Max; Koelmans, Albert A; Besseling, Ellen; Kroeze, Carolien</p> <p>2017-12-15</p> <p>Quantifying the transport of plastic debris from river to sea is crucial for assessing the risks of plastic debris to human health and the environment. We present a global modelling approach to analyse the composition and quantity of point-source microplastic fluxes from European rivers to the sea. The model accounts for different types and sources of microplastics entering river systems via point sources. We combine information on these sources with information on sewage management and plastic retention during river transport for the largest European rivers. Sources of microplastics include personal care products, laundry, household dust and tyre and road wear particles (TRWP). Most of the modelled microplastics exported by rivers to seas are synthetic polymers from TRWP (42%) and plastic-based textiles abraded during laundry (29%). Smaller sources are synthetic polymers and plastic fibres in household dust (19%) and microbeads in personal care products (10%). Microplastic export differs largely among European rivers, as a result of differences in socio-economic development and technological status of sewage treatment facilities. About two-thirds of the microplastics modelled in this study flow into the Mediterranean and Black Sea. This can be explained by the relatively low microplastic removal efficiency of sewage treatment plants in the river basins draining into these two seas. Sewage treatment is generally more efficient in river basins draining into the North Sea, the Baltic Sea and the Atlantic Ocean. We use our model to explore future trends up to the year 2050. Our scenarios indicate that in the future river export of microplastics may increase in some river basins, but decrease in others. Remarkably, for many basins we calculate a reduction in river export of microplastics from point-sources, mainly due to an anticipated improvement in sewage treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H31H1289S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H31H1289S"><span>Hydrology and Water Quality of the Rio Chama River, Northern New Mexico: Establishing a Base Line to Manage Flows</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salvato, L.; Crossey, L. J.</p> <p>2013-12-01</p> <p>The Rio Chama is the largest stream tributary to the Rio Grande in northern New Mexico. The river's geographic location in a semiarid region results in high rates of evapotranspiration and highly variable streamflow. The Rio Chama is part of the San Juan-Chama Drinking Water Project, in which water from the San Juan River, southern Colorado, is diverted across the continental divide to the Rio Chama. Surface water moves through Abiquiu, El Vado and Heron Reservoirs to the Rio Grande to supply Albuquerque with potable drinking water. The results of these anthropogenic influences are a modified flow regime, less variability, greater base-flows, and smaller peak flows. We examined selected locations throughout the Rio Chama system to provide base-line water quality data for ongoing studies. This information will contribute to the development of the best plan to optimize flow releases and maximize benefits of the stakeholders and especially the riparian and stream ecosystems. We report results of two sampling trips representing extremes of the hydrograph in summer 2012 and fall 2012. We collected field parameters, processed water samples, and analyzed them for major anions and cations. The geochemistry enables us to better understand the impact of monthly releases of San Juan river water. We captured two points of the river's streamflow range, 54 cubic feet per second in October 2012 and 1,000 cubic feet per second in August 2012 and looked for variability within the results. We found that the reservoirs exhibit varying anion concentrations from samples taken at different depths. We compared stream waters and selected well samples at a stream transect. These samples allowed us to compare shallow ground water with the stream, and they indicated that the changes in ground water are attributed to sulfate reduction. The anion and cation inputs were most likely derived from gypsum, calcite, and salts, as there are many creeks discharging into the Rio Chama whose drainage basins contain exposures of strata bearing these minerals. We established base-line information at the extremes of flow, and our future work will integrate repeat sampling with water level data to more robustly correlate water quality characteristics with release flows. Rio Chama River, Northern New Mexico</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA567619','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA567619"><span>Design of a Free-running, 1/30th Froude Scaled Model Destroyer for In-situ Hydrodynamic Flow Visualization</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2012-06-01</p> <p>Accessed 21 March 2012]. [12] ITTC Resistance Committee, "Final Report and Recommendations to the 26th ITTC," SNAME, Rio de Janeiro , 2011. [13] E. V...operating in open water, whether it is the Charles River or a local rock quarry, the depth to draft ratio will remain above the minimum value of...e.g. the Charles River , Boston Harbor, or a local rock quarry. The model will serve as a flexible test platform for future research within the MIT</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.water.usgs.gov/wri024161','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/wri024161"><span>Surface water-ground water interactions along the lower Dungeness River and vertical hydraulic conductivity of streambed sediments, Clallam County, Washington, September 1999-July 2001</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Simonds, F. William; Sinclair, Kirk A.</p> <p>2002-01-01</p> <p>The Dungeness River emerges from the Olympic Mountains and flows generally north toward the Strait of Juan De Fuca, crossing the broad, fertile alluvial fan of the Sequim-Dungeness peninsula in northeastern Clallam County, Washington. Increasing competition for the peninsula's ground-water resources, changing water-use patterns, and recent requirements to maintain minimum in-stream flows to enhance endangered salmon and trout populations have severely strained the peninsula's water resources and necessitated a better understanding of the interaction between surface water and groundwater. Three methods were used to characterize the interchange between surface water and groundwater along the lower 11.8 miles of the Dungeness River corridor between September 1999 and July 2001. In-stream mini-piezometers were used to measure vertical hydraulic gradients between the river and the water-table aquifer at 27 points along the river and helped to define the distribution of gaining and losing stream reaches. Seepage runs were used to quantify the net volume of water exchanged between the river and ground water within each of five river reaches, termed 'seepage reaches.' Continuous water-level and water-temperature monitoring at two off-stream well transects provided data on near-river horizontal hydraulic gradients and temporal patterns of water exchange for a representative gaining stream reach and a representative losing stream reach. Vertical hydraulic gradients in the mini-piezometers generally were negative between river miles 11.8 and 3.6, indicating loss of water from the river to ground water. Gradients decreased in the downstream direction from an average of -0.86 at river mile 10.3 to -0.23 at river mile 3.7. Small positive gradients (+0.01 to +0.02) indicating ground-water discharge occurred in three localized reaches below river mile 3.7. Data from the seepage runs and off-stream transect wells supported and were generally consistent with the mini-piezometer findings. An exception occurred between river miles 8.1 and 5.5 where seepage results showed a small gain and the mini-piezometers showed negative gradients. Vertical hydraulic conductivity of riverbed sediments was estimated using hydraulic gradients measured with the mini-piezometers and estimated seepage fluxes. The resulting conductivity values ranged from an average of 1 to 29 feet per day and are similar to values reported for similar river environments elsewhere. The results of this study will be used to calibrate a transient, three-dimensional ground-water flow model of the Sequim-Dungeness peninsula. The model will be used to assess the potential effects on ground-water levels and river flows that result from future water use and land-use changes on the peninsula.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H33K..01W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H33K..01W"><span>Process Based Modelling of Climate Change Impacts on River Water Quality: Case studies from the England, Wales and Scotland</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Whitehead, P. G.; Jin, L.; Futter, M.; Crossman, J.</p> <p>2011-12-01</p> <p>A modelling study has been undertaken as part of a UK Water Industry Research Project to study and assess the likely impacts of climate change on river water quality across the UK. A range of climate scenarios (http://ukclimateprojections.defra.gov.uk/ ) have been used to generate future precipitation, evaporation and temperature time series at a range of catchments across the UK. These time series have then been used to drive the Integrated Catchment Model (INCA) suite to simulate flow, nitrate, ammonia, total and soluble reactive phosphorus, sediments, dissolved organic carbon (DOC) in the Rivers Tamar, Lugg, Tame, Kennet, Tweed and Lambourn. A wide range of responses have been obtained with impacts varying depending on river character, catchment location, flow regime, type of scenario and the time into the future. For example, The INCA-DOC model has been applied to the Hore catchment of the upper Severn catchment at Plynlimon, Wales. DOC is becoming an issue in the UK uplands due to rising trends in recent years. The trends are thought to be due primarily to reducing sulphur deposition but the climate variability certainly has an effect. This is because when peats dry out the oxidation processes enhance the production of DOC. The INCA-DOC model has been used to assess potential changes in DOC under the 2020s and 2050s climate. These results show quite large rises in October and September months when the soils become saturated and flush DOC. The INCA-N results for the Rivers Tweed (Scotland) and Kennet (England) suggest that nitrate and ammonia concentrations will be slightly higher in the winter months under the climate change scenarios, perhaps reflecting the higher flushing of nitrogen load from the catchment soils. However, in summer month nitrates fall significantly which reflects enhanced denitrification processes in the rivers. However, lower down the rivers where major point sources from effluents affect the river, nitrates and ammonia may increase because of lower flows in summer and hence less dilution. Modelling phosphorus and sediments in the Rivers Lugg, Tame and the Wensum (England) suggest phosphorus concentrations will decrease in summer due to lower flows in rural areas and the reduced flushing of diffuse sources of P from agricultural areas. However, in catchments with significant effluent discharges, the P concentrations will increase due to the reduced dilution of effluents. Sediments will increase with intense rainfall during winter months, although the increased frequency of storms, especially in summer months, will generate higher concentrations as sediments are flushed from the catchments. However, mean summer sediment concentrations will be lower due to the reduced diffuse runoff from agricultural areas. Finally it is worth pointing out that adaptation measures are possible with mitigation measures to control N deposition, fertiliser application rates, reintroducing wetlands and land management control.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JHyd..552..718R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JHyd..552..718R"><span>Long-term data set analysis of stable isotopic composition in German rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reckerth, Anne; Stichler, Willibald; Schmidt, Axel; Stumpp, Christine</p> <p>2017-09-01</p> <p>Stable isotopes oxygen-18 (18O) and deuterium (2H) are commonly used to investigate hydrological processes in catchments. However, only a few isotope studies have been conducted on a large scale and rarely over long time periods. The objective of this study was to identify the spatial and seasonal variability of isotopic composition in river water and how it is affected by geographical and hydrological factors. The stable isotopic composition of river water has been measured in nine large river catchments in Germany for a time period of 12 years or 26 years. We conducted time series and correlation analyses to identify spatial and temporal patterns of the isotopic composition in the rivers. Further, we compared it to isotopic composition in local precipitation and catchments characteristics. In the majority of the rivers, the spatial and temporal patterns of precipitation were directly reflected in river water. The isotopic signals of the river water were time shifted and show attenuated amplitudes. Further deviations from isotopic compositions in local precipitation were observed in catchments with complex flow systems. These deviations were attributed to catchment processes and influences like evaporation, damming and storage. The seasonality of the isotopic composition was mainly determined by the discharge regimes of the rivers. We found correlations between isotopic long-term averages and catchment altitude as well as latitude and longitude, resulting in a northwest-southeast gradient. Furthermore, it was shown that long-term averages of d-excess were inversely related to flow length and catchment size, which indicates that evaporation enrichment has an impact on the isotopic composition even in catchments of humid climates. This study showed that isotopic composition in rivers can serve as a proxy for the local precipitation and can be utilized as an indicator for hydrological processes even in large river basins. In future, such long time series will help to also understand the impact of changes in the hydrological cycle on the larger scales. They can also be used for calibration and validation of flow and transport models at catchment and sub-catchment scale.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70021994','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70021994"><span>The economic value of Trinity River water</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Douglas, A.J.; Taylor, J.G.</p> <p>1999-01-01</p> <p>The Trinity River, largest tributary of the Klamath River, has its head-waters in the Trinity Alps of north-central California. After the construction of Trinity Dam in 1963, 90% of the Trinity River flow at Lewiston was moved to the Sacramento River via the Clear Creek Tunnel, a manmade conduit. Hydropower is produced at four installations along the route of Trinity River water that is diverted to the Sacramento River, and power production at three of these installations would diminish if no Trinity River water were diverted to the Sacramento River. After Trinity River water reaches the Sacramento River, it flows toward the Sacramento-San Joaquin Delta and San Francisco Bay. Trinity River water is pumped via Bureau of Reclamation canals and pumps to the northern San Joaquin Valley, where it is used for irrigated agriculture. The social cost of putting more water down the Trinity River is the sum of the value of the foregone consumer surplus from hydropower production as well as the value of the foregone irrigation water. Sharply diminished instream flows have also severely affected the size and robustness of Trinity River salmon, steelhead, shad and sturgeon runs. Survey data were used to estimate the non-market benefits of augmenting Trinity River instream flows by letting more water flow down the Trinity and moving less water to the Sacramento River. Preservation benefits for Trinity River instream flows and fish runs are $803 million per annum for the scenario that returns the most water down the Trinity River, a value that greatly exceeds the social cost estimate.The Trinity River, largest tributary of the Klamath River, has its headwaters in the Trinity Alps of north-central California. After the construction of Trinity Dam in 1963, 90% of the Trinity River flow at Lewiston was moved to the Sacramento River via the Clear Creek Tunnel, a manmade conduit. Hydropower is produced at four installations along the route of Trinity River water that is diverted to the Sacramento River, and power production at three of these installations would diminish if no Trinity River water were diverted to the Sacramento River. After Trinity River water reaches the Sacramento River, it flows toward the Sacramento-San Joaquin Delta and San Francisco Bay. Trinity River water is pumped via Bureau of Reclamation canals and pumps to the northern San Joaquin Valley, where it is used for irrigated agriculture. The social cost of putting more water down the Trinity River is the sum of the value of the foregone consumer surplus from hydropower production as well as the value of the foregone irrigation water. Sharply diminished instream flows have also severely affected the size and robustness of Trinity River salmon, steelhead, shad and sturgeon runs. Survey data were used to estimate the non-market benefits of augmenting Trinity River instream flows by letting more water flow down the Trinity and moving less water to the Sacramento River. Preservation benefits for Trinity River instream flows and fish runs are $803 million per annum for the scenario that returns the most water down the Trinity River, a value that greatly exceeds the social cost estimate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70189268','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70189268"><span>Understanding uncertainties in future Colorado River streamflow</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Julie A. Vano,; Bradley Udall,; Cayan, Daniel; Jonathan T Overpeck,; Brekke, Levi D.; Das, Tapash; Hartmann, Holly C.; Hidalgo, Hugo G.; Hoerling, Martin P; McCabe, Gregory J.; Morino, Kiyomi; Webb, Robert S.; Werner, Kevin; Lettenmaier, Dennis P.</p> <p>2014-01-01</p> <p>The Colorado River is the primary water source for more than 30 million people in the United States and Mexico. Recent studies that project streamf low changes in the Colorado River all project annual declines, but the magnitude of the projected decreases range from less than 10% to 45% by the mid-twenty-first century. To understand these differences, we address the questions the management community has raised: Why is there such a wide range of projections of impacts of future climate change on Colorado River streamflow, and how should this uncertainty be interpreted? We identify four major sources of disparities among studies that arise from both methodological and model differences. In order of importance, these are differences in 1) the global climate models (GCMs) and emission scenarios used; 2) the ability of land surface and atmospheric models to simulate properly the high-elevation runoff source areas; 3) the sensitivities of land surface hydrology models to precipitation and temperature changes; and 4) the methods used to statistically downscale GCM scenarios. In accounting for these differences, there is substantial evidence across studies that future Colorado River streamflow will be reduced under the current trajectories of anthropogenic greenhouse gas emissions because of a combination of strong temperature-induced runoff curtailment and reduced annual precipitation. Reconstructions of preinstrumental streamflows provide additional insights; the greatest risk to Colorado River streamf lows is a multidecadal drought, like that observed in paleoreconstructions, exacerbated by a steady reduction in flows due to climate change. This could result in decades of sustained streamflows much lower than have been observed in the ~100 years of instrumental record.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JHyd..522..558S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JHyd..522..558S"><span>Water reuse in river basins with multiple users: A literature review</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Simons, G. W. H. (Gijs); Bastiaanssen, W. G. M. (Wim); Immerzeel, W. W. (Walter)</p> <p>2015-03-01</p> <p>Unraveling the interaction between water users in a river basin is essential for sound water resources management, particularly in a context of increasing water scarcity and the need to save water. While most attention from managers and decision makers goes to allocation and withdrawals of surface water resources, reuse of non-consumed water gets only marginal attention despite the potentially significant volumes. As a consequence, claims of water saving are often grossly exaggerated. It is the purpose of this paper to explore the processes associated with water reuse in a river basin among users of varying nature and review existing methods for directly or indirectly describing non-consumed water, recoverable flow and/or water reuse. First a conceptual representation of processes surrounding water withdrawals and associated definitions is discussed, followed by a section on connectivity between individual withdrawals and the complex dynamics arising from dependencies and tradeoffs within a river basin. The current state-of-the-art in categorizing basin hydrological flows is summarized and its applicability to a water system where reuse occurs is explored. The core of the paper focuses on a selection and demonstration of existing indicators developed for assessing water reuse and its impacts. It is concluded that although several methods for analyses of water reuse and recoverable flows have been developed, a number of essential aspects of water reuse are left out of existing indicators. Moreover, a proven methodology for obtaining crucial quantitative information on recoverable flows is currently lacking. Future studies should aim at spatiotemporal tracking of the recoverable portion of water withdrawals and showing the dependency of multiple water users on such flows to water policy makers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25710600','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25710600"><span>Statistical analysis and ANN modeling for predicting hydrological extremes under climate change scenarios: the example of a small Mediterranean agro-watershed.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kourgialas, Nektarios N; Dokou, Zoi; Karatzas, George P</p> <p>2015-05-01</p> <p>The purpose of this study was to create a modeling management tool for the simulation of extreme flow events under current and future climatic conditions. This tool is a combination of different components and can be applied in complex hydrogeological river basins, where frequent flood and drought phenomena occur. The first component is the statistical analysis of the available hydro-meteorological data. Specifically, principal components analysis was performed in order to quantify the importance of the hydro-meteorological parameters that affect the generation of extreme events. The second component is a prediction-forecasting artificial neural network (ANN) model that simulates, accurately and efficiently, river flow on an hourly basis. This model is based on a methodology that attempts to resolve a very difficult problem related to the accurate estimation of extreme flows. For this purpose, the available measurements (5 years of hourly data) were divided in two subsets: one for the dry and one for the wet periods of the hydrological year. This way, two ANNs were created, trained, tested and validated for a complex Mediterranean river basin in Crete, Greece. As part of the second management component a statistical downscaling tool was used for the creation of meteorological data according to the higher and lower emission climate change scenarios A2 and B1. These data are used as input in the ANN for the forecasting of river flow for the next two decades. The final component is the application of a meteorological index on the measured and forecasted precipitation and flow data, in order to assess the severity and duration of extreme events. Copyright © 2015 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2013/5106/pdf/sir2013-5106_web.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2013/5106/pdf/sir2013-5106_web.pdf"><span>Hydraulic and water-quality data collection for the investigation of Great Lakes tributaries for Asian carp spawning and egg-transport suitability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Murphy, Elizabeth A.; Jackson, P. Ryan</p> <p>2013-01-01</p> <p>While hydraulic data from all four rivers indicated settling of eggs is possible in some locations, all four rivers also exhibited sufficient temperatures, water-quality characteristics, turbulence, and transport times outside of settling zones for successful suspension and development of Asian carp eggs to the hatching stage before the threat of settlement. These observed data indicate that these four Great Lakes tributaries have sufficient hydraulic and water-quality characteristics to support successful spawning and recruitment of Asian carps. The data indicate that with the right temperature and flow conditions, river reaches as short as 25 km may allow Asian carp eggs sufficient time to develop to hatching. Additionally, examining the relation between critical shear velocity and mean velocity, egg settling appears to take place at mean velocities in the range of 15–25 centimeters per second, a much lower value than is generally cited in the literature. A first-order estimate of the minimum transport velocity for Asian carp eggs in a river can be obtained by using mean flow depth and river substrate data, and curves were constructed to show this relation. These findings would expand the number of possible tributaries suitable for Asian carp spawning and contribute to the understanding of how hydraulic and water-quality information can be used to screen additional rivers in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H23D1693S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H23D1693S"><span>Hyporheic Zone Residence Time Distributions in Regulated River Corridors</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Song, X.; Chen, X.; Shuai, P.; Gomez-Velez, J. D.; Ren, H.; Hammond, G. E.</p> <p>2017-12-01</p> <p>Regulated rivers exhibit stage fluctuations at multiple frequencies due to both natural processes (e.g., seasonal cycle) and anthropogenic activities (e.g., dam operation). The interaction between the dynamic river flow conditions and the heterogeneous aquifer properties results in complex hydrologic exchange pathways that are ubiquitous in free-flowing and regulated river corridors. The dynamic nature of the exchange flow is reflected in the residence time distribution (RTD) of river water within the groundwater system, which is a key metric that links river corridor biogeochemical processes with the hydrologic exchange. Understanding the dynamics of RTDs is critical to gain the mechanistic understanding of hydrologic exchange fluxes and propose new parsimonious models for river corridors, yet it is understudied primarily due to the high computational demands. In this study, we developed parallel particle tracking algorithms to reveal how river flow variations affect the RTD of river water in the alluvial aquifer. Particle tracking was conducted using the velocity outputs generated by three-dimensional groundwater flow simulations of PFLOTRAN in a 1600 x 800 x 20m model domain within the DOE Hanford Site. Long-term monitoring data of inland well water levels and river stage were used for eight years of flow simulation. Nearly a half million particles were continually released along the river boundary to calculate the RTDs. Spectral analysis of the river stage data revealed high-frequency (sub-daily to weekly) river stage fluctuations caused by dam operations. The higher frequencies of stage variation were progressively filtered to generate multiple sets of flow boundary conditions. A series of flow simulations were performed by using the filtered flow boundary conditions and various degrees of subsurface heterogeneity to study the relative contribution of flow dynamics and physical heterogeneity on river water RTD. Our results revealed multimodal RTDs of river water as a result of the highly variable exchange pathways driven by interactions between dynamic flow and aquifer heterogeneity. A relationship between the RTD and frequency of flow variation was built for each heterogeneity structure, which can be used to assess the potential ecological consequences of dam operations in regulated rivers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70194379','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70194379"><span>Application of synthetic scenarios to address water resource concerns: A management-guided case study from the Upper Colorado River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McAfee, Stephanie A.; Pederson, Gregory T.; Woodhouse, Connie A.; McCabe, Gregory</p> <p>2017-01-01</p> <p>Water managers are increasingly interested in better understanding and planning for projected resource impacts from climate change. In this management-guided study, we use a very large suite of synthetic climate scenarios in a statistical modeling framework to simultaneously evaluate how (1) average temperature and precipitation changes, (2) initial basin conditions, and (3) temporal characteristics of the input climate data influence water-year flow in the Upper Colorado River. The results here suggest that existing studies may underestimate the degree of uncertainty in future streamflow, particularly under moderate temperature and precipitation changes. However, we also find that the relative severity of future flow projections within a given climate scenario can be estimated with simple metrics that characterize the input climate data and basin conditions. These results suggest that simple testing, like the analyses presented in this paper, may be helpful in understanding differences between existing studies or in identifying specific conditions for physically based mechanistic modeling. Both options could reduce overall cost and improve the efficiency of conducting climate change impacts studies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20956366','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20956366"><span>A model-based assessment of the effects of projected climate change on the water resources of Jordan.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wade, A J; Black, E; Brayshaw, D J; El-Bastawesy, M; Holmes, P A C; Butterfield, D; Nuimat, S; Jamjoum, K</p> <p>2010-11-28</p> <p>This paper is concerned with the quantification of the likely effect of anthropogenic climate change on the water resources of Jordan by the end of the twenty-first century. Specifically, a suite of hydrological models are used in conjunction with modelled outcomes from a regional climate model, HadRM3, and a weather generator to determine how future flows in the upper River Jordan and in the Wadi Faynan may change. The results indicate that groundwater will play an important role in the water security of the country as irrigation demands increase. Given future projections of reduced winter rainfall and increased near-surface air temperatures, the already low groundwater recharge will decrease further. Interestingly, the modelled discharge at the Wadi Faynan indicates that extreme flood flows will increase in magnitude, despite a decrease in the mean annual rainfall. Simulations projected no increase in flood magnitude in the upper River Jordan. Discussion focuses on the utility of the modelling framework, the problems of making quantitative forecasts and the implications of reduced water availability in Jordan.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29665147','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29665147"><span>Detrimental effects of a novel flow regime on the functional trajectory of an aquatic invertebrate metacommunity.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ruhi, Albert; Dong, Xiaoli; McDaniel, Courtney H; Batzer, Darold P; Sabo, John L</p> <p>2018-04-17</p> <p>Novel flow regimes resulting from dam operations and overallocation of freshwater resources are an emerging consequence of global change. Yet, anticipating how freshwater biodiversity will respond to surging flow regime alteration requires overcoming two challenges in environmental flow science: shifting from local to riverscape-level understanding of biodiversity dynamics, and from static to time-varying characterizations of the flow regime. Here, we used time-series methods (wavelets and multivariate autoregressive models) to quantify flow-regime alteration and to link time-varying flow regimes to the dynamics of multiple local communities potentially connected by dispersal (i.e., a metacommunity). We studied the Chattahoochee River below Buford dam (Georgia, U.S.A.), and asked how flow regime alteration by a large hydropower dam may control the long-term functional trajectory of the downstream invertebrate metacommunity. We found that seasonal variation in hydropeaking synchronized temporal fluctuations in trait abundance among the flow-altered sites. Three biological trait states describing adaptation to fast flows benefitted from flow management for hydropower, but did not compensate for declines in 16 "loser" traits. Accordingly, metacommunity-wide functional diversity responded negatively to hydropeaking intensity, and stochastic simulations showed that the risk of functional diversity collapse within the next 4 years would decrease by 17% if hydropeaking was ameliorated, or by 9% if it was applied every other season. Finally, an analysis of 97 reference and 23 dam-affected river sites across the U.S. Southeast suggested that flow variation at extraneous, human-relevant scales (12-hr, 24-hr, 1-week) is relatively common in rivers affected by hydropower dams. This study advances the notion that novel flow regimes are widespread, and simplify the functional structure of riverine communities by filtering out taxa with nonadaptive traits and by spatially synchronizing their dynamics. This is relevant in the light of ongoing and future hydrologic alteration due to climate non-stationarity and the new wave of dams planned globally. © 2018 John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25918888','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25918888"><span>Water resources planning for a river basin with recurrent wildfires.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Santos, R M B; Sanches Fernandes, L F; Pereira, M G; Cortes, R M V; Pacheco, F A L</p> <p>2015-09-01</p> <p>Situated in the north of Portugal, the Beça River basin is subject to recurrent wildfires, which produce serious consequences on soil erosion and nutrient exports, namely by deteriorating the water quality in the basin. In the present study, the ECO Lab tool embedded in the Mike Hydro Basin software was used for the evaluation of river water quality, in particular the dissolved concentration of phosphorus in the period 1990-2013. The phosphorus concentrations are influenced by the burned area and the river flow discharge, but the hydrologic conditions prevail: in a wet year (2000, 16.3 km(2) of burned area) with an average flow of 16.4 m(3)·s(-1) the maximum phosphorus concentration was as low as 0.02 mg·L(-1), while in a dry year (2005, 24.4 km(2) of burned area) with an average flow of 2 m(3)·s(-1) the maximum concentration was as high as 0.57 mg·L(-1). Phosphorus concentrations in the water bodies exceeded the bounds of good ecological status in 2005 and between 2009 and 2012, water for human consumption in 2009 and water for multiple uses in 2010. The River Covas, a right margin tributary of Beça River, is the most appropriate stream as regards the use of water for human consumption, because it presents the biggest water potential with the best water quality. Since wildfires in the basin result essentially from natural causes and climate change forecasts indicate an increase in their frequency and intensity in the near future, forestry measures are proposed to include as a priority the conversion of stands of maritime pine in mixed stands of conifer and hardwood species. Copyright © 2015 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AIPC.1903j0010H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AIPC.1903j0010H"><span>River flow modeling using artificial neural networks in Kapuas river, West Kalimantan, Indonesia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Herawati, Henny; Suripin, Suharyanto</p> <p>2017-11-01</p> <p>Kapuas River is located in the province of West Kalimantan. Kapuas river length is 1,086 km and river basin areas about 100,000 Km2. The availability of river flow data in the Long River and very wide catchments are difficult to obtain, while river flow data are essential for planning waterworks. To predict the water flow in the catchment area requires a lot of hydrology coefficient, so it is very difficult to predict and obtain results that closer to the real conditions. This paper demonstrates that artificial neural network (ANN) could be used to predict the water flow. The ANN technique can be used to predict the incidence of water discharge that occurs in the Kapuas River based on rainfall and evaporation data. With the data available to do training on the artificial neural network model is obtained mean square error (MSE) 0.00007. The river flow predictions could be carried out after the training. The results showed differences in water discharge measurement and prediction of about 4%.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1989/0243/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1989/0243/report.pdf"><span>Hydraulic characteristics of the New River in the New River Gorge National River, West Virginia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wiley, J.B.; Appel, David H.</p> <p>1989-01-01</p> <p>Traveltime, dispersion, water-surface and streambed profiles, and cross-section data were collected for use in application of flow and solute-transport models to the New River in the New River Gorge National River, West Virginia. Dye clouds subjected to increasing and decreasing flow rates (unsteady flow) showed that increasing flows shorten the cloud and decreasing flows lengthen the cloud. After the flow rate was changed and the flow was again steady, traveltime and dispersion characteristics were determined by the new rate of flow. Seven stage/streamflow relations identified the general changes of stream geometry throughout the study reach. Channel cross sections were estimated for model input. Low water and streambed profiles were developed from surveyed water surface elevations and water depths. (USGS)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4199630','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4199630"><span>Modeling the Evolution of Riparian Woodlands Facing Climate Change in Three European Rivers with Contrasting Flow Regimes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rivaes, Rui P.; Rodríguez-González, Patricia M.; Ferreira, Maria Teresa; Pinheiro, António N.; Politti, Emilio; Egger, Gregory; García-Arias, Alicia; Francés, Felix</p> <p>2014-01-01</p> <p>Global circulation models forecasts indicate a future temperature and rainfall pattern modification worldwide. Such phenomena will become particularly evident in Europe where climate modifications could be more severe than the average change at the global level. As such, river flow regimes are expected to change, with resultant impacts on aquatic and riparian ecosystems. Riparian woodlands are among the most endangered ecosystems on earth and provide vital services to interconnected ecosystems and human societies. However, they have not been the object of many studies designed to spatially and temporally quantify how these ecosystems will react to climate change-induced flow regimes. Our goal was to assess the effects of climate-changed flow regimes on the existing riparian vegetation of three different European flow regimes. Cases studies were selected in the light of the most common watershed alimentation modes occurring across European regions, with the objective of appraising expected alterations in the riparian elements of fluvial systems due to climate change. Riparian vegetation modeling was performed using the CASiMiR-vegetation model, which bases its computation on the fluvial disturbance of the riparian patch mosaic. Modeling results show that riparian woodlands may undergo not only at least moderate changes for all flow regimes, but also some dramatic adjustments in specific areas of particular vegetation development stages. There are circumstances in which complete annihilation is feasible. Pluvial flow regimes, like the ones in southern European rivers, are those likely to experience more pronounced changes. Furthermore, regardless of the flow regime, younger and more water-dependent individuals are expected to be the most affected by climate change. PMID:25330151</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018WRR....54.1513L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018WRR....54.1513L"><span>Spatiotemporal Responses of Groundwater Flow and Aquifer-River Exchanges to Flood Events</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, Xiuyu; Zhan, Hongbin; Schilling, Keith</p> <p>2018-03-01</p> <p>Rapidly rising river stages induced by flood events lead to considerable river water infiltration into aquifers and carry surface-borne solutes into hyporheic zones which are widely recognized as an important place for the biogeochemical activity. Existing studies for surface-groundwater exchanges induced by flood events usually limit to a river-aquifer cross section that is perpendicular to river channels, and neglect groundwater flow in parallel with river channels. In this study, surface-groundwater exchanges to a flood event are investigated with specific considerations of unconfined flow in direction that is in parallel with river channels. The groundwater flow is described by a two-dimensional Boussinesq equation and the flood event is described by a diffusive-type flood wave. Analytical solutions are derived and tested using the numerical solution. The results indicate that river water infiltrates into aquifers quickly during flood events, and mostly returns to the river within a short period of time after the flood event. However, the rest river water will stay in aquifers for a long period of time. The residual river water not only flows back to rivers but also flows to downstream aquifers. The one-dimensional model of neglecting flow in the direction parallel with river channels will overestimate heads and discharge in upstream aquifers. The return flow induced by the flood event has a power law form with time and has a significant impact on the base flow recession at early times. The solution can match the observed hydraulic heads in riparian zone wells of Iowa during flood events.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.H31F1061C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.H31F1061C"><span>The Cumberland River Flood of 2010 and Corps Reservoir Operations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Charley, W.; Hanbali, F.; Rohrbach, B.</p> <p>2010-12-01</p> <p>On Saturday, May 1, 2010, heavy rain began falling in the Cumberland River Valley and continued through the following day. 13.5 inches was measured at Nashville, an unprecedented amount that doubled the previous 2-day record, and exceeded the May monthly total record of 11 inches. Elsewhere in the valley, amounts of over 19 inches were measured. The frequency of this storm was estimated to exceed the one-thousand year event. This historic rainfall brought large scale flooding to the Cumberland-Ohio-Tennessee River Valleys, and caused over 2 billion dollars in damages, despite the numerous flood control projects in the area, including eight U.S. Army Corps of Engineers projects. The vast majority of rainfall occurred in drainage areas that are uncontrolled by Corps flood control projects, which lead to the wide area flooding. However, preliminary analysis indicates that operations of the Corps projects reduced the Cumberland River flood crest in Nashville by approximately five feet. With funding from the American Recovery and Reinvestment Act (ARRA) of 2009, hydrologic, hydraulic and reservoir simulation models have just been completed for the Cumberland-Ohio-Tennessee River Valleys. These models are being implemented in the Corps Water Management System (CWMS), a comprehensive data acquisition and hydrologic modeling system for short-term decision support of water control operations in real time. The CWMS modeling component uses observed rainfall and forecasted rainfall to compute forecasts of river flows into and downstream of reservoirs, using HEC-HMS. Simulation of reservoir operations, utilizing either the HEC-ResSim or CADSWES RiverWare program, uses these flow scenarios to provide operational decision information for the engineer. The river hydraulics program, HEC-RAS, computes river stages and water surface profiles for these scenarios. An inundation boundary and depth map of water in the flood plain can be calculated from the HEC-RAS results using ArcInfo. The economic impacts of the different inundation depths are computed by HEC-FIA. The user-configurable sequence of modeling software allows engineers to evaluate operational decisions for reservoirs and other control structures, and view and compare hydraulic and economic impacts for various “what if?” scenarios. This paper reviews the Cumberland River May 2010 event, the impact of Corps reservoirs and reservoir operations and the expected future benefits and effects of the ARRA funded models and CWMS on future events for this area.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H33F1774K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H33F1774K"><span>Weak Learner Method for Estimating River Discharges using Remotely Sensed Data: Central Congo River as a Testbed</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, D.; Lee, H.; Yu, H.; Beighley, E.; Durand, M. T.; Alsdorf, D. E.; Hwang, E.</p> <p>2017-12-01</p> <p>River discharge is a prerequisite for an understanding of flood hazard and water resource management, yet we have poor knowledge of it, especially over remote basins. Previous studies have successfully used a classic hydraulic geometry, at-many-stations hydraulic geometry (AMHG), and Manning's equation to estimate the river discharge. Theoretical bases of these empirical methods were introduced by Leopold and Maddock (1953) and Manning (1889), and those have been long used in the field of hydrology, water resources, and geomorphology. However, the methods to estimate the river discharge from remotely sensed data essentially require bathymetric information of the river or are not applicable to braided rivers. Furthermore, the methods used in the previous studies adopted assumptions of river conditions to be steady and uniform. Consequently, those methods have limitations in estimating the river discharge in complex and unsteady flow in nature. In this study, we developed a novel approach to estimating river discharges by applying the weak learner method (here termed WLQ), which is one of the ensemble methods using multiple classifiers, to the remotely sensed measurements of water levels from Envisat altimetry, effective river widths from PALSAR images, and multi-temporal surface water slopes over a part of the mainstem Congo. Compared with the methods used in the previous studies, the root mean square error (RMSE) decreased from 5,089 m3s-1 to 3,701 m3s-1, and the relative RMSE (RRMSE) improved from 12% to 8%. It is expected that our method can provide improved estimates of river discharges in complex and unsteady flow conditions based on the data-driven prediction model by machine learning (i.e. WLQ), even when the bathymetric data is not available or in case of the braided rivers. Moreover, it is also expected that the WLQ can be applied to the measurements of river levels, slopes and widths from the future Surface Water Ocean Topography (SWOT) mission to be launched in 2021.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2016/5158/sir20165158.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2016/5158/sir20165158.pdf"><span>Flow characteristics and salinity patterns of tidal rivers within the northern Ten Thousand Islands, southwest Florida, water years 2007–14</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Booth, Amanda C.; Soderqvist, Lars E.</p> <p>2016-12-12</p> <p>Freshwater flow to the Ten Thousand Islands estuary has been altered by the construction of the Tamiami Trail and the Southern Golden Gate Estates. The Picayune Strand Restoration Project, which is associated with the Comprehensive Everglades Restoration Plan, has been implemented to improve freshwater delivery to the Ten Thousand Islands estuary by removing hundreds of miles of roads, emplacing hundreds of canal plugs, removing exotic vegetation, and constructing three pump stations. Quantifying the tributary flows and salinity patterns prior to, during, and after the restoration is essential to assessing the effectiveness of upstream restoration efforts.Tributary flow and salinity patterns during preliminary restoration efforts and prior to the installation of pump stations were analyzed to provide baseline data and preliminary analysis of changes due to restoration efforts. The study assessed streamflow and salinity data for water years1 2007–2014 for the Faka Union River (canal flow included), East River, Little Wood River, Pumpkin River, and Blackwater River. Salinity data from the Palm River and Faka Union Boundary water-quality stations were also assessed.Faka Union River was the dominant contributor of freshwater during water years 2007–14 to the Ten Thousand Islands estuary, followed by Little Wood and East Rivers. Pumpkin River and Blackwater River were the least substantial contributors of freshwater flow. The lowest annual flow volumes, the highest annual mean salinities, and the highest percentage of salinity values greater than 35 parts per thousand (ppt) occurred in water year 2011 at all sites with available data, corresponding with the lowest annual rainfall during the study. The highest annual flow volumes and the lowest percentage of salinities greater than 35 ppt occurred in water year 2013 for all sites with available data, corresponding with the highest rainfall during the study.In water year 2014, the percentage of monitored annual flow contributed by East River increased and the percentage of flow contributed by Faka Union River decreased, compared to the earlier years. No changes in annual flow occurred at any sites west of Faka Union River. No changes in the relative flow contributions were observed during the wet season; however, the relative amounts of streamflow increased during the dry season at East River in 2014. East River had only 1 month of negative flow in 2014 compared to 6 months in 2011 and 7 months in 2008. Higher dry season flows in East River may be in response to restoration efforts. The sites to the west of Faka Union River had higher salinities on average than Faka Union River and East River. Faka Union River had the highest range in salinities, and Faka Union Boundary had the lowest range in salinities. Pumpkin River was the tributary with the lowest range in salinities.1Water year is defined as the 12-month period from October 1, for any given year, through September 30 of the following year.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70174897','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70174897"><span>First direct confirmation of grass carp spawning in a Great Lakes tributary</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Embke, Holly S.; Kocovsky, Patrick M.; Richter, Catherine A.; Pritt, Jeremy J.; Christine M. Mayer,; Qian, Song</p> <p>2016-01-01</p> <p>Grass carp (Ctenopharyngodon idella), an invasive species of Asian carp, has been stocked for many decades in the United States for vegetation control. Adult individuals have been found in all of the Great Lakes except Lake Superior, but no self-sustaining populations have yet been identified in Great Lakes tributaries. In 2012, a commercial fisherman caught four juvenile diploid grass carp in the Sandusky River, a major tributary to Lake Erie. Otolith microchemistry and the capture location of these fish permitted the conclusion that they were most likely produced in the Sandusky River. Due to this finding, we sampled ichthyoplankton using paired bongo net tows and larval light traps during June–August of 2014 and 2015 to determine if grass carp are spawning in the Sandusky River. From the samples collected in 2015, we identified and staged eight eggs that were morphologically consistent with grass carp. Five eggs were confirmed as grass carp using quantitative Polymerase Chain Reaction for a grass carp-specific marker, while the remaining three were retained for future analysis. Our finding confirms that grass carp are naturally spawning in this Great Lakes tributary. All eggs were collected during high-flow events, either on the day of peak flow or 1–2 days following peak flow, supporting an earlier suggestion that high flow conditions favor grass carp spawning. The next principal goal is to identify the spawning and hatch location(s) for the Sandusky River. Predicting locations and conditions where grass carp spawning is most probable may aid targeted management efforts.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29758861','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29758861"><span>Advancing towards functional environmental flows for temperate floodplain rivers.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hayes, Daniel S; Brändle, Julia M; Seliger, Carina; Zeiringer, Bernhard; Ferreira, Teresa; Schmutz, Stefan</p> <p>2018-08-15</p> <p>Abstraction, diversion, and storage of flow alter rivers worldwide. In this context, minimum flow regulations are applied to mitigate adverse impacts and to protect affected river reaches from environmental deterioration. Mostly, however, only selected instream criteria are considered, neglecting the floodplain as an indispensable part of the fluvial ecosystem. Based on essential functions and processes of unimpaired temperate floodplain rivers, we identify fundamental principles to which we must adhere to determine truly ecologically-relevant environmental flows. Literature reveals that the natural flow regime and its seasonal components are primary drivers for functions and processes of abiotic and biotic elements such as morphology, water quality, floodplain, groundwater, riparian vegetation, fish, macroinvertebrates, and amphibians, thus preserving the integrity of floodplain river ecosystems. Based on the relationship between key flow regime elements and associated environmental components within as well as adjacent to the river, we formulate a process-oriented functional floodplain flow (ff-flow) approach which offers a holistic conceptual framework for environmental flow assessment in temperate floodplain river systems. The ff-flow approach underlines the importance of emulating the natural flow regime with its seasonal variability, flow magnitude, frequency, event duration, and rise and fall of the hydrograph. We conclude that the ecological principles presented in the ff-flow approach ensure the protection of floodplain rivers impacted by flow regulation by establishing ecologically relevant environmental flows and guiding flow restoration measures. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018HESS...22.1735S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018HESS...22.1735S"><span>Scaling properties reveal regulation of river flows in the Amazon through a <q>forest reservoir</q></span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salazar, Juan Fernando; Villegas, Juan Camilo; María Rendón, Angela; Rodríguez, Estiven; Hoyos, Isabel; Mercado-Bettín, Daniel; Poveda, Germán</p> <p>2018-03-01</p> <p>Many natural and social phenomena depend on river flow regimes that are being altered by global change. Understanding the mechanisms behind such alterations is crucial for predicting river flow regimes in a changing environment. Here we introduce a novel physical interpretation of the scaling properties of river flows and show that it leads to a parsimonious characterization of the flow regime of any river basin. This allows river basins to be classified as regulated or unregulated, and to identify a critical threshold between these states. We applied this framework to the Amazon river basin and found both states among its main tributaries. Then we introduce the <q>forest reservoir</q> hypothesis to describe the natural capacity of river basins to regulate river flows through land-atmosphere interactions (mainly precipitation recycling) that depend strongly on the presence of forests. A critical implication is that forest loss can force the Amazonian river basins from regulated to unregulated states. Our results provide theoretical and applied foundations for predicting hydrological impacts of global change, including the detection of early-warning signals for critical transitions in river basins.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGC13B0632S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGC13B0632S"><span>Interactions Between Land Use, Climate and Hydropower in Scotland</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sample, J.</p> <p>2014-12-01</p> <p>To promote the transition towards a low carbon economy, the Scottish Government has adopted ambitious energy targets, including generating all electricity from renewable sources by 2020. To achieve this, continued investment will be required across a range of sustainable technologies. Hydropower has a long history in Scotland and the present-day operational capacity of ~1.5 GW makes a substantial contribution to the national energy budget. In addition, there remains potential for ~500 MW of further development, mostly in the form of small to medium size run-of-river schemes. Climate change is expected to lead to an intensification of the global hydrological cycle, leading to changes in both the magnitude and seasonality of river flows. There may also be indirect effects, such as changing land use, enhanced evapotranspiration rates and an increased demand for irrigation, all of which could affect the water available for energy generation. Preliminary assessments of hydropower commonly use flow duration curves (FDCs) to estimate the power generation potential at proposed new sites. In this study, we use spatially distributed modelling to generate daily and monthly FDCs for a range of Scottish catchments using a variety of future land use and climate change scenarios. These are then used to assess Scotland's future hydropower potential under different flow regimes. The results are spatially variable and include large uncertainties, but some consistent patterns emerge. Many locations are predicted to experience enhanced seasonality, with lower power generation potential in the summer months and greater potential during the autumn and winter. Some sites may require infrastructural changes in order to continue operating at optimum efficiency. We discuss the implications and limitations of our results, and highlight design and adaptation options for maximising the resilience of hydropower installations under changing future flow patterns.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5383045','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5383045"><span>Qualitative simulation of bathymetric changes due to reservoir sedimentation: A Japanese case study</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dai, Wenhong; Larson, Magnus; Beebo, Qaid Naamo; Xie, Qiancheng</p> <p>2017-01-01</p> <p>Sediment-dynamics modeling is a useful tool for estimating a dam’s lifespan and its cost–benefit analysis. Collecting real data for sediment-dynamics analysis from conventional field survey methods is both tedious and expensive. Therefore, for most rivers, the historical record of data is either missing or not very detailed. Available data and existing tools have much potential and may be used for qualitative prediction of future bathymetric change trend. This study shows that proxy approaches may be used to increase the spatiotemporal resolution of flow data, and hypothesize the river cross-sections and sediment data. Sediment-dynamics analysis of the reach of the Tenryu River upstream of Sakuma Dam in Japan was performed to predict its future bathymetric changes using a 1D numerical model (HEC-RAS). In this case study, only annually-averaged flow data and the river’s longitudinal bed profile at 5-year intervals were available. Therefore, the other required data, including river cross-section and geometry and sediment inflow grain sizes, had to be hypothesized or assimilated indirectly. The model yielded a good qualitative agreement, with an R2 (coefficient of determination) of 0.8 for the observed and simulated bed profiles. A predictive simulation demonstrated that the useful life of the dam would end after the year 2035 (±5 years), which is in conformity with initial detailed estimates. The study indicates that a sediment-dynamic analysis can be performed even with a limited amount of data. However, such studies may only assess the qualitative trends of sediment dynamics. PMID:28384361</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2013/3021/pdf/fs2013-3021.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2013/3021/pdf/fs2013-3021.pdf"><span>Modeled future peak streamflows in four coastal Maine rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hodgkins, Glenn A.; Dudley, Robert W.</p> <p>2013-01-01</p> <p>To safely and economically design bridges and culverts, it is necessary to compute the magnitude of peak streamflows that have specified annual exceedance probabilities (AEPs). These peak flows are also needed for effective floodplain management. Annual precipitation and air temperature in the northeastern United States are in general projected to increase during the 21st century (Hayhoe and other, 2007). It is therefore important for engineers and resource managers to understand how peak flows may change in the future. This Fact Sheet, prepared in cooperation with the Maine Department of Transportation, presents a summary of modeled changes in peak flows at four basins in coastal Maine on the basis of projected changes in air temperature and precipitation. The full Scientific Investigations Report (Hodgkins and Dudley, 2013) is available at http://pubs.usgs.gov/sir/2013/5080/.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2011/5044/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2011/5044/"><span>Assessment of groundwater/surface-water interaction and simulation of potential streamflow depletion induced by groundwater withdrawal, Uinta River near Roosevelt, Utah</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lambert, P.M.; Marston, T.; Kimball, B.A.; Stolp, B.J.</p> <p>2011-01-01</p> <p>Roosevelt City, Utah, asserts a need for an additional supply of water to meet municipal demands and has identified a potential location for additional groundwater development at the Sprouse well field near the West Channel of the Uinta River. Groundwater is commonly hydraulically linked to surface water and, under some conditions, the pumpage of groundwater can deplete water in streams and other water bodies. In 2008, the U.S. Geological Survey, in cooperation with Roosevelt City, the Utah Department of Natural Resources, and the Ute Indian Tribe, began a study to improve understanding of the local interconnection between groundwater and surface water and to assess the potential for streamflow depletion from future groundwater withdrawals at a potential Roosevelt City development location—the Sprouse well field near the West Channel of the Uinta River.In the study, streamflow gains and losses at the river/aquifer boundary near the well field and changes in those conditions over time were assessed through (1) synoptic measurement of discharge in the stream at multiple sites using tracer-dilution methods, (2) periodic measurement of the vertical hydraulic gradient across the streambed, and (3) continuous measurement of stream and streambed water temperature using heat as a tracer of flow across the streambed. Although some contradictions among the results of the three assessment methods were observed, results of the approaches generally indicated (1) losing streamflow conditions on the West Channel of the Uinta River north of and upstream from the Sprouse well field within the study area, (2) gaining streamflow conditions south of and downstream from the well field, and (3) some seasonal changes in those conditions that correspond with seasonal changes in stream stage and local water-table altitudes.A numerical groundwater flow model was developed on the basis of previously reported observations and observations made during this study, and was used to estimate potential streamflow depletion that might result from future groundwater withdrawals at the Sprouse well field. The model incorporates concepts of transient groundwater flow conditions including fluctuations in groundwater levels and storage, and the distribution of and temporal variations in gains to and losses from streamflow in the West Channel of the Uinta River near the Sprouse well field. Two predictive model simulations incorporated additional future discharge from the Sprouse well field totaling 325 acre-feet annually and biennially during summer months. Results of the predictive model simulations indicate that the water withdrawn by the additional pumping was derived initially from aquifer storage and then, with time, predominantly from streamflow depletion. By the 10th year of the predictive simulation incorporating annual summer pumping from an additional public-supply well in the Sprouse well field, the simulation results indicate that 89 percent of a future annual 325 acre-feet of discharge is derived from depletion of streamflow in the West Channel of the Uinta River. A similar result was observed in a predictive model simulating the same discharge rate but with the new well being pumped every other year.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H41K1411D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H41K1411D"><span>Assessing Climate Change Impacts on Water Allocation in Karkheh River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davtalabsabet, R.; Madani, K.; Massah, A.; Farajzadeh, M.</p> <p>2013-12-01</p> <p>Rahman Davtalab1, 2, Kaveh Madani2, Alireza Massah3, Manouchehr Farajzadeh1 1Department of Geography, Tarbiat Modares University, Tehran, Iran 2Department of Civil, Environmental and Construction Engineering, University of Central Florida, Orlando, FL 32816, USA 3Department of Irrigation and Drainage Engineering, College of Abureyhan , University of Tehran, Iran Abstract Karkheh river basin, with an area of 50,000 km2 is located, in southwest Iran. This basin supplies water for major agricultural activities and large hydropower production in five Iranian provinces with the total population of four million people. Due to development and population growth, this large trans-boundary basin is incapable of meeting the water demands of the five riparian provinces, causing water allocation conflicts in the region. The situation has been exacerbated by the frequent droughts and is expected to worsen further by climate change. This study evaluates the impacts of climate change on water supply reliability and allocation in this basin. First, outputs of several General Circulation Models (GCMs) under different emission scenarios for different future time horizons are statistically downscaled. Then multiple river flow time series (RFTS) are generated by feeding GCM outputs into a HEC-HMS model, using the Soil Moisture Accounting (SMA). Given a wide range of variations in GCM outputs and the resulting RFTS, the Ward's method is used to identity different RFTS clusters. Clustering helps with increasing the ability of the modeler to test a range of possible future conditions while reducing the redundancies in input data. Karkheh river basin's ability to meet the growing demand under decreasing flows is evaluated for each RFTS cluster representative. Results indicate that Karkheh river flow might decrease by 50% toward the end of the century. This would decrease the reliability of agricultural water deliveries from 78-95% to less than 50%. While currently hydropower dams can only use 50% of their generation capacity for electricity production due to limited water availability, this figure would reduce to less than 30% with climate change. Several adaptation strategies are suggested based on the findings to minimize the economic losses of climate change in this developing basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018HydJ...26..267B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018HydJ...26..267B"><span>Development of a hydrogeological conceptual wetland model in the data-scarce north-eastern region of Kilombero Valley, Tanzania</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burghof, Sonja; Gabiri, Geofrey; Stumpp, Christine; Chesnaux, Romain; Reichert, Barbara</p> <p>2018-02-01</p> <p>Understanding groundwater/surface-water interactions in wetlands is crucial because wetlands provide not only a high potential for agricultural production, but also sensitive and valuable ecosystems. This is especially true for the Kilombero floodplain wetland in Tanzania, which represents a data-scarce region in terms of hydrological and hydrogeological data. A comprehensive approach combining hydrogeological with tracer-based assessments was conducted, in order to develop a conceptual hydrogeological wetland model of the area around the city of Ifakara in the north-eastern region of Kilombero catchment. Within the study site, a heterogeneous porous aquifer, with a range of hydraulic conductivities, is underlain by a fractured-rock aquifer. Groundwater chemistry is mainly influenced by silicate weathering and depends on groundwater residence times related to the hydraulic conductivities of the porous aquifer. Groundwater flows from the hillside to the river during most of the year. While floodwater close to the river is mainly derived from overbank flow of the river, floodwater at a greater distance from the river mainly originates from precipitation and groundwater discharge. Evaporation effects in floodwater increase with increasing distance from the river. In general, the contribution of flood and stream water to groundwater recharge is negligible. In terms of an intensification of agricultural activities in the wetland, several conclusions can be drawn from the conceptual model. Results of this study are valuable as a base for further research related to groundwater/surface-water interactions and the conceptual model can be used in the future to set up numerical flow and transport models.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1980/0449/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1980/0449/report.pdf"><span>Water-quality reconnaissance of the Middle and North Branch Park River watersheds, northeastern North Dakota</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ackerman, D.J.</p> <p>1980-01-01</p> <p>In order to design a network to monitor the effects of works of improvement in the Middle and North Branch Park River watersheds, and to determine the major factors controlling water-quality conditions in the watersheds, an evaluation of sediment transport, water chemistry, and biology was conducted during the spring and early summer of 1978.Major factors controlling water quality are geology, stream gradient, ground-water seepage, and the duration of streamflow.Sediment loads originate on the Pembina Escarpment. The coarse silt and sand parts of these loads are deposited on the Lake Agassiz Plain. Transport of sediment is lowered and flow duration is increased on the Middle Branch Park River due to the presence of small dams. Observations suggest that bedload transport is a significant process, particularly in the upstream reaches. However, no quantitative bedload data were collected.During periods of low flow, analyses of water from the rivers in both watersheds show downstream increases in sodium and chloride due to ground-water seepage or the unregulated flow of wells. Diversity of benthic invertebrates indicates water-quality conditions are better on the Middle Branch Park River than on the North Branch, and are better at upstream sites than at downstream sites. A program through which the Soil Conservation Service can monitor the effects of present and future works of improvement on the watersheds was designed. The monitoring program consists of intensive sampling at four locations for sediment and water chemistry during spring and early summer runoff events and by profiles of water chemistry during summer base runoff.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2015/1047/pdf/ofr2015-1047.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2015/1047/pdf/ofr2015-1047.pdf"><span>Geomorphic mapping to support river restoration on the Trinity River downstream from Lewiston Dam, California, 1980-2011</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Curtis, Jennifer A.; Guerrero, Timothy M.</p> <p>2015-01-01</p> <p>Historic land use, dam construction, water storage, and flow diversions in the Trinity River watershed have resulted in downstream geomorphic change, loss of salmonid habitat, and declines in salmonid populations. The USGS in cooperation with the Trinity River Restoration Program, a multi-agency partnership tasked with implementing federally mandated restoration, completed a geomorphic change assessment to inform the planning process for future restoration work. This report documents an ARCMAP geodatabase (v.10.0) containing geomorphic features digitized from a series of rectified orthophotographs (http://dx.doi.org/10.5066/F7TT4P04). Upland, riparian, and channel features were digitized from six available base images (1980, 1997, 2001, 2006, 2009, and 2011). This report describes the structure of the geodatabase and the methods used to delineate individual geomorphic features.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H53I1585P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H53I1585P"><span>Modeling and Remote Sensing of Surface Water Dynamics in the Mekong River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pokhrel, Y. N.</p> <p>2017-12-01</p> <p>The Mekong river is one of the most complex river systems in the world that is shared by six nations in Southeast Asia. The river still remains relatively undammed (most existing dams are in the tributaries and are small), and its hydrology today is dominated by large natural flow variations that support the highly productive agricultural and riverine ecological systems; however, this is changing due to the alterations in land use and construction of new dams both in the tributaries the mainstream (16 mainstream and 110 tributary dams are planned to be completed by 2030). Understanding the changes in surface water dynamics is therefore crucial to provide realistic future predictions of changes in downstream floodplain and riverine ecology due to the construction of dams in the upstream. In this study, we use an integrated hydrological model and remote sensing data to examine the critical role of surface water systems in modulating the river-floodplain ecology in the lower reach of the basin, with a focus on the Tonle Sap lake. We present results on the changes in the seasonality and long-term trend in river-floodplain inundation extent over the past few decades. These results provide new insights on the changing hydrology of the Mekong and important implications for potential future hydrologic changes under accelerating human activities and climate change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.water.usgs.gov/sir2004-5301/','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/sir2004-5301/"><span>Effects of alternative instream-flow criteria and water-supply demands on ground-water development options in the Big River Area, Rhode Island</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Granato, Gregory E.; Barlow, Paul M.</p> <p>2005-01-01</p> <p>Transient numerical ground-water-flow simulation and optimization techniques were used to evaluate potential effects of instream-flow criteria and water-supply demands on ground-water development options and resultant streamflow depletions in the Big River Area, Rhode Island. The 35.7 square-mile (mi2) study area includes three river basins, the Big River Basin (30.9 mi2), the Carr River Basin (which drains to the Big River Basin and is 7.33 mi2 in area), the Mishnock River Basin (3.32 mi2), and a small area that drains directly to the Flat River Reservoir. The overall objective of the simulations was to determine the amount of ground water that could be withdrawn from the three basins when constrained by streamflow requirements at four locations in the study area and by maximum rates of withdrawal at 13 existing and hypothetical well sites. The instream-flow requirement for the outlet of each basin and the outfall of Lake Mishnock were the primary variables that limited the amount of ground water that could be withdrawn. A requirement to meet seasonal ground-water-demand patterns also limits the amount of ground water that could be withdrawn by up to about 50 percent of the total withdrawals without the demand-pattern constraint. Minimum water-supply demands from a public water supplier in the Mishnock River Basin, however, did not have a substantial effect on withdrawals in the Big River Basin. Hypothetical dry-period instream-flow requirements and the effects of artificial recharge also affected the amount of ground water that could be withdrawn. Results of simulations indicate that annual average ground-water withdrawal rates that range up to 16 million gallons per day (Mgal/d) can be withdrawn from the study area under simulated average hydrologic conditions depending on instream-flow criteria and water-supply demand patterns. Annual average withdrawals of 10 to 12 Mgal/d are possible for proposed demands of 3.4 Mgal/d in the Mishnock Basin, and for a constant annual instream-flow criterion of 0.5 cubic foot per second per square mile (ft3/s/mi2) at the four streamflow-constraint locations. An average withdrawal rate of 10 Mgal/d can meet estimates of future (2020) water-supply needs of surrounding communities in Rhode Island. This withdrawal rate represents about 13 percent of the average 2002 daily withdrawal from the Scituate Reservoir (76 Mgal/d), the State?s largest water supply. Average annual withdrawal rates of 6 to 7 Mgal/d are possible for more stringent instream-flow criteria that might be used during dry-period hydrologic conditions. Two example scenarios of dry-period instream-flow constraints were evaluated: first, a minimum instream flow of 0.1 cubic foot per second at any of the four constraint locations; and second, a minimum instream flow of 10 percent of the minimum monthly streamflow estimate for each streamflow-constraint location during the period 1961?2000. The State of Rhode Island is currently (2004) considering methods for establishing instream-flow criteria for streams within the State. Twelve alternative annual, seasonal, or monthly instream-flow criteria that have been or are being considered for application in southeastern New England were used as hypothetical constraints on maximum ground-water-withdrawal rates in management-model calculations. Maximum ground-water-withdrawal rates ranged from 5 to 16 Mgal/d under five alternative annual instream-flow criteria. Maximum ground-water-withdrawal rates ranged from 0 to 13.6 Mgal/d under seven alternative seasonal or monthly instream-flow criteria. The effect of ground-water withdrawals on seasonal variations in monthly average streamflows under each criterion also were compared. Evaluation of management-model results indicates that a single annual instream-flowcriterion may be sufficient to preserve seasonal variations in monthly average streamflows and meet water-supply demands in the Big River Area, because withdrawals from wells in the Big</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AIPC.1870d0011A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AIPC.1870d0011A"><span>A pilot study of river flow prediction in urban area based on phase space reconstruction</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adenan, Nur Hamiza; Hamid, Nor Zila Abd; Mohamed, Zulkifley; Noorani, Mohd Salmi Md</p> <p>2017-08-01</p> <p>River flow prediction is significantly related to urban hydrology impact which can provide information to solve any problems such as flood in urban area. The daily river flow of Klang River, Malaysia was chosen to be forecasted in this pilot study which based on phase space reconstruction. The reconstruction of phase space involves a single variable of river flow data to m-dimensional phase space in which the dimension (m) is based on the optimal values of Cao method. The results from the reconstruction of phase space have been used in the forecasting process using local linear approximation method. From our investigation, river flow at Klang River is chaotic based on the analysis from Cao method. The overall results provide good value of correlation coefficient. The value of correlation coefficient is acceptable since the area of the case study is influence by a lot of factors. Therefore, this pilot study may be proposed to forecast daily river flow data with the purpose of providing information about the flow of the river system in urban area.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1995/4022/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1995/4022/report.pdf"><span>Synthesis of natural flows at selected sites in and near the Milk River basin, Montana, 1928-89</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cary, L.E.; Parrett, Charles</p> <p>1995-01-01</p> <p>Natural monthly streamflows were synthesized for the years 1928-89 at 2 sites in the St. Mary River Basin and 11 sites in the Milk River Basin in north- central Montana. The sites are represented as nodes in a streamflow accounting model being developed by the Bureau of Reclamation for the Milk River Basin. Recorded flows at most sites have been affected by human activities, including reservoir storage and irrigation diversions. The flows at the model nodes were corrected for the effects of these activities to obtain synthesized flows. The synthesized flows at nodes with seasonal and short-term records were extended using a statistical technique. The methods of synthesis varied, depending on upstream activities and information available. Flows at sites in the St. Mary River Basin and at the Milk River at Eastern Crossing of International Boundary pre- viously had been synthesized. The flows at mainstem sites downstream from the Milk River at Eastern Crossing were synthesized by adding synthesized natural runoff from intervening drainage areas to natural flows for Milk River at Eastern Crossing. Natural runoff from intervening drainage areas was estimated by multiplying recorded flows at selected index gaging stations on tributary streams by the ratio of the intervening drainage area to the combined drainage area of the index stations. The recorded flows for Milk River at Western Crossing of International Boundary and for Peoples Creek near Dodson, Montana, were assumed to be natural flows. The synthesized annual flows at the mouth of the Milk River compared favorably with the recorded flows near the mouth when the effects of upstream irrigation were considered.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70028639','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70028639"><span>Factors influencing soil invertebrate communities in riparian grasslands of the central platte river floodplain</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Davis, C.A.; Austin, J.E.; Buhl, D.A.</p> <p>2006-01-01</p> <p>In the Platte River Valley of central Nebraska, USA, riparian grasslands (also known as wet meadows) have been severely impacted by a reduction in river flows, causing lower ground-water levels and altered seasonal hydroperiods. The potential impacts of these hydrologic changes, as well as the environmental factors that influence wet meadow soil invertebrate communities, are not well understood. An understanding of the ecological processes that influence these invertebrate communities is crucial for maintaining and restoring wet meadows along the Platte River. Our objectives were to describe the soil invertebrate community of wet meadows throughout the growing season and to examine the relative roles of abiotic factors in determining patterns in invertebrate community structure. We conducted the study in 12 wet meadows along the Platte River during 1999 and 2000. We identified 73 invertebrate taxa; 39 were considered soil inhabitants. Total biomass was primarily composed of earthworms, Scarabaeidae, Isopoda, and Elateridae, with earthworms and Scarabaeidae accounting for >82%. Differences in river flow and precipitation patterns influenced some soil invertebrates. Earthworms and Scarabaeidae declined dramatically from 1999 (wet year) to 2000 (dry year). The topographic gradient created by the ridge-swale complex affected several soil invertebrate taxa; Scarabaeidae, Diplopoda, and Lepidoptera biomasses were greatest on drier ridges, while Tipulidae and Isopoda biomasscs were greatest in wetter sloughs. Responses of earthworm taxa to the topographic gradient were variable, but generally, greater biomasses occurred on ridges and mid-elevations. Water-table depth and soil moisture were the most important variables influencing wet meadow soil invertebrates. Because these communities are linked to the hydrologic processes of the Platte River, future alterations of wet meadow hydrology could shift the distribution patterns of many of these invertebrates and possibly eliminate more moisture-tolerant taxa. To maintain wet meadows and their biotic communities, flow management should focus on regaining as much as possible of the former hydrograph through properly timed flows that provide an adequate hydrologic regime for wet meadows. In addition, restoration of wet meadows will depend on restoring the natural topography of wet meadows. ?? 2006, The Society of Wetland Scientists.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2008/5223/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2008/5223/"><span>Evaluation of Floodplain Modifications to Reduce the Effect of Floods Using a Two-Dimensional Hydrodynamic Model of the Flint River at Albany, Georgia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Musser, Jonathan W.</p> <p>2008-01-01</p> <p>Potential flow characteristics of future flooding along a 4.8-mile reach of the Flint River in Albany, Georgia, were simulated using recent digital-elevation-model data and the U.S. Geological Survey finite-element surface-water modeling system for two-dimensional flow in the horizontal plane (FESWMS-2DH). The model was run at four water-surface altitudes at the Flint River at Albany streamgage (02352500): 181.5-foot (ft) altitude with a flow of 61,100 cubic feet per second (ft3/s), 184.5-ft altitude with a flow of 75,400 ft3/s, 187.5-ft altitude with a flow of 91,700 ft3/s, and 192.5-ft altitude with a flow of 123,000 ft3/s. The model was run to measure changes in inundated areas and water-surface altitudes for eight scenarios of possible modifications to the 4.8-mile reach on the Flint River. The eight scenarios include removing a human-made peninsula located downstream from Oglethorpe Boulevard, increasing the opening under the Oakridge Drive bridge, adding culverts to the east Oakridge Drive bridge approach, adding culverts to the east and west Oakridge Drive bridge approaches, adding an overflow across the oxbow north of Oakridge Drive, making the overflow into a channel, removing the Oakridge Drive bridge, and adding a combination of an oxbow overflow and culverts on both Oakridge Drive bridge approaches. The modeled inundation and water-surface altitude changes were mapped for use in evaluating the river modifications. The most effective scenario at reducing inundated area was the combination scenario. At the 187.5-ft altitude, the inundated area decreased from 4.24 square miles to 4.00 square miles. The remove-peninsula scenario was the least effective with a reduction in inundated area of less than 0.01 square miles. In all scenarios, the inundated area reduction increased with water-surface altitude, peaking at the 187.5-ft altitude. The inundated area reduction then decreased at the gage altitude of 192.5 ft.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70022838','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70022838"><span>Restoring ecological integrity of great rivers: Historical hydrographs aid in defining reference conditions for the Missouri River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Galat, D.L.; Lipkin, R.</p> <p>2000-01-01</p> <p>Restoring the ecological integrity of regulated large rivers necessitates characterizing the natural flow regime. We applied 'Indicators of Hydrologic Alteration' to assess the natural range of variation of the Missouri River's flow regime at 11 locations before (1929-1948) and after (1967-1996) mainstem impoundment. The 3768 km long Missouri River was divided into three sections: upper basin least-altered from flow regulation, including the lower Yellowstone River; middle basin inter-reservoir, and lower basin channelized. Flow regulation was associated with a reduction in magnitude and duration of the annual flood pulse, an increase in magnitude and duration of annual discharge minima, a reduction in frequency of annual low-flow pulses, earlier timing of March-October low-flow pulses, and a general increase in frequency of flow reversals with a reduction in the rate of change in river flows. Hydrologic alterations were smallest at two least-altered upper-basin sites and most frequent and severe in inter-reservoir and upper-channelized river sections. The influence of reservoir operations on depressing the annual flood pulse was partially offset by tributary inflow in the lower 600 km of river. Reservoir operations could be modified to more closely approximate the 1929-1948 flow regime to establish a simulated natural riverine ecosystem. For inter-reservoir and upper channelized-river sections, we recommend periodic controlled flooding through managed reservoir releases during June and July; increased magnitude, frequency and duration of annual high-flow pulses; and increased annual rates of hydrograph rises and falls. All of the regulated Missouri River would benefit from reduced reservoir discharges during August-February, modified timing of reservoir releases and a reduced number of annual hydrograph reversals. Assessment of ecological responses to a reregulation of Missouri River flows that more closely approximates the natural flow regime should then be used in an adaptive fashion to further adjust reservoir operations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2010/5163/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2010/5163/"><span>Low-flow characteristics of the Mississippi River upstream from the Twin Cities Metropolitan Area, Minnesota, 1932-2007</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kessler, Erich; Lorenz, David L.</p> <p>2010-01-01</p> <p>The U.S. Geological Survey, in cooperation with the Metropolitan Council, conducted a study to characterize regional low flows during 1932?2007 in the Mississippi River upstream from the Twin Cities metropolitan area in Minnesota and to describe the low-flow profile of the Mississippi River between the confluence of the Crow River and St. Anthony Falls. Probabilities of extremely low flow were estimated for the streamflow-gaging station (Mississippi River near Anoka) and the coincidence of low-flow periods, defined as the extended periods (at least 7 days) when all the daily flows were less than the 10th percentile of daily mean flows for the entire period of record, at four selected streamflow-gaging stations located upstream. The likelihood of extremely low flows was estimated by a superposition method for the Mississippi River near Anoka that created 5,776 synthetic hydrographs resulting in a minimum synthetic low flow of 398 cubic feet per second at a probability of occurrence of 0.0002 per year. Low-flow conditions at the Mississippi River above Anoka were associated with low-flow conditions at two or fewer of four upstream streamflow-gaging stations 42 percent of the time, indicating that sufficient water is available within the basin for many low flows and the occurrence of extremely low-flows is small. However, summer low-flow conditions at the Mississippi River above Anoka were almost always associated with low-stage elevations in three or more of the six upper basin reservoirs. A low-flow profile of the Mississippi River between the confluence of the Crow River and St. Anthony Falls was completed using a real-time kinematic global positioning system, and the water-surface profile was mapped during October 8?9, 2008, and annotated with local landmarks. This was done so that water-use planners could relate free-board elevations of selected water utility structures to the lowest flow conditions during 2008.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ECSS..196..301Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ECSS..196..301Z"><span>Tidal impacts on the subtidal flow division at the main bifurcation in the Yangtze River Delta</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Wei; Feng, Haochuan; Hoitink, A. J. F.; Zhu, Yuliang; Gong, Fei; Zheng, Jinhai</p> <p>2017-09-01</p> <p>Flow division at bifurcations in the Yangtze Estuary has received ample attention, since it may control the pathways of terrestrial sediments over downstream river branches including the 12.5 m Deepwater Navigation channel. While some efforts have been made to interpret flow division at the bifurcations of the Yangtze Estuary, little attention has been paid to the role of tides. Flow division at estuarine bifurcations is made complicated by tides that propagate from the outlet of the tidal channels into the delta. To quantify the tidal influence on the distribution of river discharge, and more generally, to understand the mechanisms governing the subtidal flow division at the tidally affected bifurcation in the Yangtze River Delta, a two-dimensional hydrodynamic model is employed. In this model, the landward boundary is chosen beyond the tidal limit, where the tidal motion has faded out entirely. The seaward boundary is chosen such that the river discharge does not influence the water level. Subtidal discharges are decomposed using the method of factor separation, to distinguish between the effects of tides, river discharge and river-tide interactions on the subtidal flow division. Results indicate that tides modify the river discharge distribution over distributary channels in the Yangtze River Delta, particularly in the dry season. A significant difference in the subtidal flow division during spring tide and neap tide shows that the tidally averaged flow division over the distributaries in the delta greatly depends on tidal amplitude. By varying the river discharge at the landward boundary and amplitudes and phases of the principal tidal constituents at the seaward boundary of the established model, the sensitivities of the subtidal flow division to the river discharge and tidal amplitude variation were investigated in detail. Generally, the tidal impacts on the subtidal flow division are around 12% to 22%, with river discharge varying from 30,000 m3s-1 to 20,000 m3s-1. This effect on the flow distribution can even overwhelm the effects induced by river discharge based on geometry only, when the flow discharge is lowest. Furthermore, the fortnightly tidal cycle plays an important role in enhancing the inequality of the subtidal flow division caused by the M2 tidal component solely at the tidal bifurcation in the Yangtze River Delta during low flow.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26204066','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26204066"><span>Evaluation of environmental flow requirements using eco-hydrologic-hydraulic methods in perennial rivers.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abdi, Reza; Yasi, Mehdi</p> <p>2015-01-01</p> <p>The assessment of environmental flows in rivers is of vital importance for preserving riverine ecosystem processes. This paper addresses the evaluation of environmental flow requirements in three reaches along a typical perennial river (the Zab transboundary river, in north-west Iran), using different hydraulic, hydrological and ecological methods. The main objective of this study came from the construction of three dams and inter-basin transfer of water from the Zab River to the Urmia Lake. Eight hydrological methods (i.e. Tennant, Tessman, flow duration curve analysis, range of variability approach, Smakhtin, flow duration curve shifting, desktop reserve and 7Q2&10 (7-day low flow with a 2- and 10-year return period)); two hydraulic methods (slope value and maximum curvature); and two habitat simulation methods (hydraulic-ecologic, and Q Equation based on water quality indices) were used. Ecological needs of the riverine key species (mainly Barbus capito fish), river geometries, natural flow regime and the environmental status of river management were the main indices for determining the minimum flow requirements. The results indicate that the order of 35%, 17% and 18% of the mean annual flow are to be maintained for the upper, middle and downstream river reaches, respectively. The allocated monthly flow rates in the three Dams steering program are not sufficient to preserve the Zab River life.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/1015137','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/1015137"><span>The demographic response of bank-dwelling beavers to flow regulation: A comparison on the Green and Yampa rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Breck, S.W.; Wilson, K.R.; Andersen, D.C.</p> <p>2001-01-01</p> <p>We assessed the effects of flow regulation on the demography of beavers (Castor canadensis) by comparing the density, home-range size, and body size of bank-dwelling beavers on two sixth-order alluvial river systems, the flow-regulated Green River and the free-flowing Yampa River, from 1997 to 2000. Flow regulation on the Green River has altered fluvial geomorphic processes, influencing the availability of willow and cottonwood, which, in turn, has influenced the demography of beavers. Beaver density was higher on the Green River (0.50.6 colonies per kilometre of river) than on the Yampa River (0.35 colonies per kilometre of river). Adult and subadult beavers on the Green River were in better condition, as indicated by larger body mass and tail size. There was no detectable difference in home-range size, though there were areas on the Yampa River that no beavers used. We attribute the improved habitat quality on the Green River to a greater availability of willow. We suggest that the sandy flats and sandbars that form during base flows and the ice cover that forms over winter on the Yampa River increase the energy expended by the beavers to obtain food and increase predation risk and thus lowers the availability of woody forage.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29607034','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29607034"><span>Projected effects of Climate-change-induced flow alterations on stream macroinvertebrate abundances.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kakouei, Karan; Kiesel, Jens; Domisch, Sami; Irving, Katie S; Jähnig, Sonja C; Kail, Jochem</p> <p>2018-03-01</p> <p>Global change has the potential to affect river flow conditions which are fundamental determinants of physical habitats. Predictions of the effects of flow alterations on aquatic biota have mostly been assessed based on species ecological traits (e.g., current preferences), which are difficult to link to quantitative discharge data. Alternatively, we used empirically derived predictive relationships for species' response to flow to assess the effect of flow alterations due to climate change in two contrasting central European river catchments. Predictive relationships were set up for 294 individual species based on (1) abundance data from 223 sampling sites in the Kinzig lower-mountainous catchment and 67 sites in the Treene lowland catchment, and (2) flow conditions at these sites described by five flow metrics quantifying the duration, frequency, magnitude, timing and rate of flow events using present-day gauging data. Species' abundances were predicted for three periods: (1) baseline (1998-2017), (2) horizon 2050 (2046-2065) and (3) horizon 2090 (2080-2099) based on these empirical relationships and using high-resolution modeled discharge data for the present and future climate conditions. We compared the differences in predicted abundances among periods for individual species at each site, where the percent change served as a proxy to assess the potential species responses to flow alterations. Climate change was predicted to most strongly affect the low-flow conditions, leading to decreased abundances of species up to -42%. Finally combining the response of all species over all metrics indicated increasing overall species assemblage responses in 98% of the studied river reaches in both projected horizons and were significantly larger in the lower-mountainous Kinzig compared to the lowland Treene catchment. Such quantitative analyses of freshwater taxa responses to flow alterations provide valuable tools for predicting potential climate-change impacts on species abundances and can be applied to any stressor, species, or region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ERL....13d4026L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ERL....13d4026L"><span>Quantifying the potential for reservoirs to secure future surface water yields in the world’s largest river basins</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Lu; Parkinson, Simon; Gidden, Matthew; Byers, Edward; Satoh, Yusuke; Riahi, Keywan; Forman, Barton</p> <p>2018-04-01</p> <p>Surface water reservoirs provide us with reliable water supply, hydropower generation, flood control and recreation services. Yet reservoirs also cause flow fragmentation in rivers and lead to flooding of upstream areas, thereby displacing existing land-use activities and ecosystems. Anticipated population growth and development coupled with climate change in many regions of the globe suggests a critical need to assess the potential for future reservoir capacity to help balance rising water demands with long-term water availability. Here, we assess the potential of large-scale reservoirs to provide reliable surface water yields while also considering environmental flows within 235 of the world’s largest river basins. Maps of existing cropland and habitat conservation zones are integrated with spatially-explicit population and urbanization projections from the Shared Socioeconomic Pathways to identify regions unsuitable for increasing water supply by exploiting new reservoir storage. Results show that even when maximizing the global reservoir storage to its potential limit (∼4.3–4.8 times the current capacity), firm yields would only increase by about 50% over current levels. However, there exist large disparities across different basins. The majority of river basins in North America are found to gain relatively little firm yield by increasing storage capacity, whereas basins in Southeast Asia display greater potential for expansion as well as proportional gains in firm yield under multiple uncertainties. Parts of Europe, the United States and South America show relatively low reliability of maintaining current firm yields under future climate change, whereas most of Asia and higher latitude regions display comparatively high reliability. Findings from this study highlight the importance of incorporating different factors, including human development, land-use activities, and climate change, over a time span of multiple decades and across a range of different scenarios when quantifying available surface water yields and the potential for reservoir expansion.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2015/5185/sir20155185.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2015/5185/sir20155185.pdf"><span>Stochastic model for simulating Souris River Basin precipitation, evapotranspiration, and natural streamflow</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kolars, Kelsey A.; Vecchia, Aldo V.; Ryberg, Karen R.</p> <p>2016-02-24</p> <p>The Souris River Basin is a 61,000-square-kilometer basin in the Provinces of Saskatchewan and Manitoba and the State of North Dakota. In May and June of 2011, record-setting rains were seen in the headwater areas of the basin. Emergency spillways of major reservoirs were discharging at full or nearly full capacity, and extensive flooding was seen in numerous downstream communities. To determine the probability of future extreme floods and droughts, the U.S. Geological Survey, in cooperation with the North Dakota State Water Commission, developed a stochastic model for simulating Souris River Basin precipitation, evapotranspiration, and natural (unregulated) streamflow. Simulations from the model can be used in future studies to simulate regulated streamflow, design levees, and other structures; and to complete economic cost/benefit analyses.Long-term climatic variability was analyzed using tree-ring chronologies to hindcast precipitation to the early 1700s and compare recent wet and dry conditions to earlier extreme conditions. The extended precipitation record was consistent with findings from the Devils Lake and Red River of the North Basins (southeast of the Souris River Basin), supporting the idea that regional climatic patterns for many centuries have consisted of alternating wet and dry climate states.A stochastic climate simulation model for precipitation, temperature, and potential evapotranspiration for the Souris River Basin was developed using recorded meteorological data and extended precipitation records provided through tree-ring analysis. A significant climate transition was seen around1970, with 1912–69 representing a dry climate state and 1970–2011 representing a wet climate state. Although there were some distinct subpatterns within the basin, the predominant differences between the two states were higher spring through early fall precipitation and higher spring potential evapotranspiration for the wet compared to the dry state.A water-balance model was developed for simulating monthly natural (unregulated) mean streamflow based on precipitation, temperature, and potential evapotranspiration at select streamflow-gaging stations. The model was calibrated using streamflow data from the U.S. Geological Survey and Environment Canada, along with natural (unregulated) streamflow data from the U.S. Army Corps of Engineers. Correlation coefficients between simulated and natural (unregulated) flows generally were high (greater than 0.8), and the seasonal means and standard deviations of the simulated flows closely matched the means and standard deviations of the natural (unregulated) flows. After calibrating the model for a monthly time step, monthly streamflow for each subbasin was disaggregated into three values per month, or an approximately 10-day time step, and a separate routing model was developed for simulating 10-day streamflow for downstream gages.The stochastic climate simulation model for precipitation, temperature, and potential evapotranspiration was combined with the water-balance model to simulate potential future sequences of 10-day mean streamflow for each of the streamflow-gaging station locations. Flood risk, as determined by equilibrium flow-frequency distributions for the dry (1912–69) and wet (1970–2011) climate states, was considerably higher for the wet state compared to the dry state. Future flood risk will remain high until the wet climate state ends, and for several years after that, because there may be a long lag-time between the return of drier conditions and the onset of a lower soil-moisture storage equilibrium.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PCE...102...21K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PCE...102...21K"><span>River flow availability for environmental flow allocation downstream of hydropower facilities in the Kafue Basin of Zambia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kalumba, Mulenga; Nyirenda, Edwin</p> <p>2017-12-01</p> <p>The Government of the Republic Zambia (GRZ) will install a new hydropower station Kafue Gorge Lower downstream of the existing Kafue Gorge Station (KGS) and plans to start operating the Itezhi-Tezhi (ITT) hydropower facility in the Kafue Basin. The Basin has significant biodiversity hot spots such as the Luangwa National park and Kafue Flats. It is described as a Man-Biosphere reserve and the National Park is a designated World Heritage Site hosting a variety of wildlife species. All these natural reserves demand special protection, and environmental flow requirements (e-flows) have been identified as a necessary need to preserve these ecosystems. Implementation of e-flows is therefore a priority as Zambia considers to install more hydropower facilities. However before allocation of e-flows, it is necessary to first assess the river flow available for allocation at existing hydropower stations in the Kafue Basin. The river flow availability in the basin was checked by assessing the variability in low and high flows since the timing, frequency and duration of extreme droughts and floods (caused by low and high flows) are all important hydrological characteristics of a flow regime that affects e-flows. The river flows for a 41 year monthly time series data (1973-2014) were used to extract independent low and high flows using the Water Engineering Time Series Processing Tool (WETSPRO). The low and high flows were used to construct cumulative frequency distribution curves that were compared and analysed to show their variation over a long period. A water balance of each hydropower station was used to check the river flow allocation aspect by comparing the calculated water balance outflow (river flow) with the observed river flow, the hydropower and consumptive water rights downstream of each hydropower station. In drought periods about 50-100 m3/s of riverflow is available or discharged at both ITT and KGS stations while as in extreme flood events about 1300-1500 m3/s of riverflow is available. There is river flow available in the wet and dry seasons for e-flow allocation at ITT. On average per month 25 m3/s is allocated for e-flows at ITT for downstream purposes. On the other hand, it may be impossible to implement e-flows at KGS with the limited available outflow (river flow). The available river flow from ITT plays a very vital role in satisfying the current hydropower generating capacity at KGS. Therefore, the operations of KGS heavily depends on the available outflow (river flow) from ITT.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/31889','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/31889"><span>The Importance and Future Condition of Western Riparian Ecosystems as Migratory Bird Habitat</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Susan K. Skagen; Rob Hazlewood; Michael L. Scott</p> <p>2005-01-01</p> <p>Riparian forests have long been considered important habitats for breeding western landbirds, and growing evidence reinforces their importance during the migratory period as well. Extensive modification of natural flow regimes, grazing, and forest clearing along many rivers in the western U.S. have led to loss and simplification of native riparian forests and to...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.H51C0329W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.H51C0329W"><span>Numerical Simulation of Ground-Water Salinization in the Arkansas River Corridor, Southwest Kansas</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Whittemore, D. O.; Perkins, S.; Tsou, M.; McElwee, C. D.; Zhan, X.; Young, D. P.</p> <p>2001-12-01</p> <p>The salinity of ground water in the High Plains aquifer underlying the upper Arkansas River corridor in southwest Kansas has greatly increased during the last few decades. The source of the salinization is infiltration of Arkansas River water along the river channel and in areas irrigated with diverted river water. The saline river water is derived from southeastern Colorado where consumptive losses of water in irrigation systems substantially concentrate dissolved solids in the residual water. Before development of surface- and ground-water resources, the Arkansas River gained flow along nearly all of its length in southwest Kansas. Since the 1970's, ground-water levels have declined in the High Plains aquifer from consumptive use of ground water. The water-level declines have now changed the river to a generally losing rather than gaining system. We simulated ground-water flow in the aquifers underlying 126 miles of the river corridor using MODFLOW integrated with the GIS software ArcView (Tsou and Whittemore, 2001). There are two layers in the model, one for the Quaternary alluvial aquifer and the other for the underlying High Plains aquifer. We prepared a simulation for circa 1940 that represented conditions prior to substantial ground-water development, and simulations for 40 years into the future that were based on holding constant either average water use or average ground-water levels for the 1990's. Streamflows along the river computed from the model results illustrated the flow gains from ground-water discharge for circa 1940 and losses during the 1990's. We modeled the movement of salinity as particle tracks generated by MODPATH based on the MODFLOW solutions. The results indicate that during the next 40 years, saline water will move a substantial distance in the High Plains aquifer on the south side of the central portion of the river valley. The differences between the circa 1940 and 1990's simulations fit the observed data that show large increases in the dissolved solids of ground waters in the High Plains aquifer in portions of the river corridor. The modeling indicates that management of water use in the aquifers on a large scale would be necessary to achieve significant changes in the rate and direction of saline water migration over a time scale of decades. >http://www.kgs.ukans.edu/Hydro/UARC/index.html</a></p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/16460','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/16460"><span>Debris flows from tributaries of the Colorado River, Grand Canyon National Park, Arizona</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Webb, R.H.; Pringle, P.T.; Rink, G.R.</p> <p>1987-01-01</p> <p>A reconnaissance of 36 tributaries of the Colorado River indicates that debris flows are a major process by which sediment is transported to the Colorado River in Grand Canyon National Park. Debris flows are slurries of sediment and water that have a water content < 40% by volume. Debris flows occur frequently in arid and semiarid regions. Slope failures commonly trigger debris flows, which can originate from any rock formation in the Grand Canyon. The largest and most frequent flows originate from the Permian Hermit Shale, the underlying Esplanade Sandstone of the Supai Group, and other formations of the Permian and Pennsylvanian Supai Group. Debris flows have reached the Colorado River on an average of once every 20 to 30 yr in the Lava-Chuar Creek drainage since about 1916. Two debris flows have reached the Colorado River in the last 25 yr in Monument Creek. The Crystal Creek drainage has had an average of one debris flow reaching the Colorado River every 50 yr, although the debris flow of 1966 has been the only flow that reached the Colorado River since 1900. Debris flows may actually reach the Colorado River more frequently in these drainages because evidence for all debris flows may not have been preserved in the channel-margin stratigraphy. Discharges were estimated for the peak flow of three debris flows that reached the Colorado River. The debris flow of 1966 in the Lava-Chuar Creek drainage had an estimated discharge of 4,000 cu ft/sec. The debris flow of 1984 in the Monument Creek drainage had a discharge estimated between 3,600 and 4,200 cu ft/sec. The debris flow of 1966 in the Crystal Creek drainage had a discharge estimated between 9,200 and 14,000 cu ft/sec. Debris flows in the Grand Canyon generally are composed of 10 to 40% sand by weight and may represent a significant source of beach-building sand along the Colorado River. The particle size distributions are very poorly sorted and the largest transported boulders were in the Crystal Creek drainage. Reworking of debris fans by the Colorado River creates debris bars that constrain the size of eddy systems and forms secondary rapids and riffles below tributary mouths. (See also W89-09239) (Lantz-PTT)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.5337B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.5337B"><span>Impact of Climate Change on high and low flows across Great Britain: a temporal analysis and uncertainty assessment.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beevers, Lindsay; Collet, Lila</p> <p>2017-04-01</p> <p>Over the past decade there have been significant challenges to water management posed by both floods and droughts. In the UK, since 2000 flooding has caused over £5Bn worth of damage, and direct costs from the recent drought (2011-12) are estimated to be between £70-165M, arising from impacts on public and industrial water supply. Projections of future climate change suggest an increase in temperature and precipitation trends which may exacerbate the frequency and severity of such hazards, but there is significant uncertainty associated with these projections. It thus becomes urgent to assess the possible impact of these changes on extreme flows and evaluate the uncertainties related to these projections, particularly changes in the seasonality of such hazards. This paper aims to assess the changes in seasonality of peak and low flows across Great Britain as a result of climate change. It is based on the Future Flow database; an 11-member ensemble of transient river flow projections from January 1951 to December 2098. We analyse the daily river flow over the baseline (1961-1990) and the 2080s (2069-2098) for 281 gauging stations. For each ensemble member, annual maxima (AMAX) and minima (AMIN) are extracted for both time periods for each gauging station. The month of the year the AMAX and AMIN occur respectively are recorded for each of the 30 years in the past and the future time periods. The uncertainty of the AMAX and AMIN occurrence temporally (monthly) is assessed across the 11 ensemble members, as well as the changes to this temporal signal between the baseline and the 2080s. Ultimately, this work gives a national picture (spatially) of high and low flows occurrence temporally and allows the assessment of possible changes in hydrological dynamics as a result of climate change in a statistical framework. Results will quantify the uncertainty related to the Climate Model parameters which are cascaded into the modelling chain. This study highlights the issues facing hydrological cycle management, due to changing spatial and temporal trends in order to anticipate and adapt to hydro-hazard changes in an uncertain context.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1915587J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1915587J"><span>Using global Climate Impact Indicators to assess water resource availability in a Mediterranean mountain catchment: the Sierra Nevada study case (Spain) in the SWICCA platform</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>José Pérez-Palazón, María; Pimentel, Rafael; Sáenz de Rodrigáñez, Marta; Gulliver, Zacarias; José Polo, María</p> <p>2017-04-01</p> <p>Climate services provide water resource managements and users with science-based information on the likely impacts associated to the future climate scenarios. Mountainous areas are especially vulnerable to climate variations due to the expected changes in the snow regime, among others; in Mediterranean regions, this shift involves significant effects on the river flow regime and water resource availability and management. The Guadalfeo River Basin is a 1345 km2 mountainous, coastal catchment in southern Spain, ranging from the Mediterranean Sea coastline to the Sierra Nevada mountains to the north (up to 3450 m a.s.l.) within a 40-km distance. The climate variability adds complexity to this abrupt topography and heterogeneous area. The uncertainty associated to snow occurrence and persistence for the next decades poses a challenge for the current and future water resource uses in the area. The development of easy-to-use local climate indicators and derived decision-making variables is key to assess and face the economic impact of the potential changes. The SWICCA (Service for Water Indicators in Climate Change Adaptation) Platform (http://swicca.climate.copernicus.eu/) has been developed under the Copernicus Climate Change Service (C3S) and provides global climate and hydrology indicators on a Pan-European scale. Different case studies are included to assess the platform development and contents, and analyse the indicators' performance from a proof-of-concept approach that includes end-users feedbacks. The Guadalfeo River Basin is one of these case studies. This work presents the work developed so far to analyse and use the SWICCA Climate Impact Indicators (CIIs) related to river flow in this mountainous area, and the first set of local indicators specifically designed to assess selected end-users on the potential impact associated to different climate scenarios. Different CIIs were extracted from the SWICCA interface and tested against the local information available in the case study. The Essential Climate Variables used were precipitation and flow daily values, obtained at different spatial scales. The analysis led to the use of SWICCA-river flow on a catchment scale as the most suitable global CIIs in this area. Further treatment included local downscaling by means of transfer functions and a final relative anomaly correction. Three final end-users (clients) were identified within the water resource management framework: 1) mini hydropower facilities at the head areas, 2) urban supply at the southern area, and 3) water management decision makers (reservoir operation). From the corrected CIIs, local indicators were defined from the interaction with each client, to tailor water services easily and readily usable. Knowledge brokering from this interaction resulted in a first identification of a set of 4, 3 and 4 indicators for hydropower generation, urban users and water resource decision-makers, respectively, with different time scales. The projections of three future climate scenarios were assessed for each indicator and presented to each client. Local indicators are an efficient tool to assess the potential range of water allocation possibilities in this area on an annual and decadal basis, and get a deeper insight of the seasonal future potential regime of water resource availability. The results are good examples of key information for decision making in the future, and show how to derive local indicators with impact in the short and medium term planning in heterogeneous catchments in this region.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070038279','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070038279"><span>On the Use of Ocean Color Remote Sensing to Measure the Transport of Dissolved Organic Carbon by the Mississippi River Plume</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>DelCastillo, Carlos E.; Miller, Richard L.</p> <p>2007-01-01</p> <p>We investigated the use of ocean color remote sensing to measure transport of dissolved organic carbon (DOC) by the Mississippi River to the Gulf of Mexico. From 2000 to 2005 we recorded surface measurements of DOC, colored dissolved organic matter (CDOM), salinity, and water-leaving radiances during five cruises to the Mississippi River Plume. These measurements were used to develop empirical relationships to derive CDOM, DOC, and salinity from monthly composites of SeaWiFS imagery collected from 1998 through 2005. We used river flow data and a two-end-member mixing model to derive DOC concentrations in the river end-member, river flow, and DOC transport using remote sensing data. We compared our remote sensing estimates of river flow and DOC transport with data collected by the United States Geological Survey (USGS) from 1998 through 2005. Our remote sensing estimates of river flow and DOC transport correlated well (r2 0.70) with the USGS data. Our remote sensing estimates and USGS field data showed low variability in DOC concentrations in the river end-member (7-11%), and high seasonal variability in river flow (50%). Therefore, changes in river flow control the variability in DOC transport, indicating that the remote sensing estimate of river flow is the most critical element of our DOC transport measurement. We concluded that it is possible to use this method to estimate DOC transport by other large rivers if there are data on the relationship between CDOM, DOC, and salinity in the river plume.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H13I1220B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H13I1220B"><span>Dynamic hydro-climatic networks in pristine and regulated rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Botter, G.; Basso, S.; Lazzaro, G.; Doulatyari, B.; Biswal, B.; Schirmer, M.; Rinaldo, A.</p> <p>2014-12-01</p> <p>Flow patterns observed at-a-station are the dynamical byproduct of a cascade of processes involving different compartments of the hydro-climatic network (e.g., climate, rainfall, soil, vegetation) that regulates the transformation of rainfall into streamflows. In complex branching rivers, flow regimes result from the heterogeneous arrangement around the stream network of multiple hydrologic cascades that simultaneously occur within distinct contributing areas. As such, flow regimes are seen as the integrated output of a complex "network of networks", which can be properly characterized by its degree of temporal variability and spatial heterogeneity. Hydrologic networks that generate river flow regimes are dynamic in nature. In pristine rivers, the time-variance naturally emerges at multiple timescales from climate variability (namely, seasonality and inter-annual fluctuations), implying that the magnitude (and the features) of the water flow between two nodes may be highly variable across different seasons and years. Conversely, the spatial distribution of river flow regimes within pristine rivers involves scale-dependent transport features, as well as regional climatic and soil use gradients, which in small and meso-scale catchments (A < 103 km2) are usually mild enough to guarantee quite uniform flow regimes and high spatial correlations. Human-impacted rivers, instead, constitute hybrid networks where observed spatio-temporal patterns are dominated by anthropogenic shifts, such as landscape alterations and river regulation. In regulated rivers, the magnitude and the features of water flows from node to node may change significantly through time due to damming and withdrawals. However, regulation may impact river regimes in a spatially heterogeneous manner (e.g. in localized river reaches), with a significant decrease of spatial correlations and network connectivity. Provided that the spatial and temporal dynamics of flow regimes in complex rivers may strongly impact important biotic processes involved in the river food web (e.g. biofilm and riparian vegetation dynamics), the study of rivers as dynamic networks provides important clues to water management strategies and freshwater ecosystem studies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JPhCS.995a2045I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JPhCS.995a2045I"><span>Comparative Analysis of River Flow Modelling by Using Supervised Learning Technique</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ismail, Shuhaida; Mohamad Pandiahi, Siraj; Shabri, Ani; Mustapha, Aida</p> <p>2018-04-01</p> <p>The goal of this research is to investigate the efficiency of three supervised learning algorithms for forecasting monthly river flow of the Indus River in Pakistan, spread over 550 square miles or 1800 square kilometres. The algorithms include the Least Square Support Vector Machine (LSSVM), Artificial Neural Network (ANN) and Wavelet Regression (WR). The forecasting models predict the monthly river flow obtained from the three models individually for river flow data and the accuracy of the all models were then compared against each other. The monthly river flow of the said river has been forecasted using these three models. The obtained results were compared and statistically analysed. Then, the results of this analytical comparison showed that LSSVM model is more precise in the monthly river flow forecasting. It was found that LSSVM has he higher r with the value of 0.934 compared to other models. This indicate that LSSVM is more accurate and efficient as compared to the ANN and WR model.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24340094','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24340094"><span>Avian community responses to variability in river hydrology.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Royan, Alexander; Hannah, David M; Reynolds, S James; Noble, David G; Sadler, Jonathan P</p> <p>2013-01-01</p> <p>River flow is a major driver of morphological structure and community dynamics in riverine-floodplain ecosystems. Flow influences in-stream communities through changes in water velocity, depth, temperature, turbidity and nutrient fluxes, and perturbations in the organisation of lower trophic levels are cascaded through the food web, resulting in shifts in food availability for consumer species. River birds are sensitive to spatial and phenological mismatches with aquatic prey following flow disturbances; however, the role of flow as a determinant of riparian ecological structure remains poorly known. This knowledge is crucial to help to predict if, and how, riparian communities will be influenced by climate-induced changes in river flow characterised by more extreme high (i.e. flood) and/or low (i.e. drought) flow events. Here, we combine national-scale datasets of river bird surveys and river flow archives to understand how hydrological disturbance has affected the distribution of riparian species at higher trophic levels. Data were analysed for 71 river locations using a Generalized Additive Model framework and a model averaging procedure. Species had complex but biologically interpretable associations with hydrological indices, with species' responses consistent with their ecology, indicating that hydrological-disturbance has implications for higher trophic levels in riparian food webs. Our quantitative analysis of river flow-bird relationships demonstrates the potential vulnerability of riparian species to the impacts of changing flow variability and represents an important contribution in helping to understand how bird communities might respond to a climate change-induced increase in the intensity of floods and droughts. Moreover, the success in relating parameters of river flow variability to species' distributions highlights the need to include river flow data in climate change impact models of species' distributions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2013/1246/pdf/ofr2013-1246.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2013/1246/pdf/ofr2013-1246.pdf"><span>Geomorphic and vegetation processes of the Willamette River floodplain, Oregon: current understanding and unanswered science questions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wallick, J. Rose; Jones, Krista L.; O'Connor, Jim E.; Keith, Mackenzie K.; Hulse, David; Gregory, Stanley V.</p> <p>2013-01-01</p> <p>4. How is the succession of native floodplain vegetation shaped by present-day flow and sediment conditions? Answering these questions will produce baseline data on the current distributions of landforms and habitats (question 1), the extent of the functional floodplain (question 2), and the effects of modern flow and sediment regimes on future floodplain landforms, habitats, and vegetation succession (questions 3 and 4). Addressing questions 1 and 2 is a logical next step because they underlie questions 3 and 4. Addressing these four questions would better characterize the modern Willamette Basin and help in implementing and setting realistic targets for ongoing management strategies, demonstrating their effectiveness at the site and basin scales, and anticipating future trends and conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70026381','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70026381"><span>Uncertainty in low-flow data from three streamflow-gaging stations on the upper Verde River, Arizona</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Anning, D.W.; ,</p> <p>2004-01-01</p> <p>The evaluation of uncertainty in low-flow data collected from three streamflow-gaging stations on the upper Verde River, Arizona, was presented. In downstream order, the stations are Verde River near Paulden, Verde River near Clarkdale, and Verde River near Camp Verde. A monitoring objective of the evaluation was to characterize discharge of the lower flow regime through a variety of procedures such as frequency analysis and base-flow analysis. For Verde River near Paulden and near Camp Verde, the uncertainty of daily low flows can be reduced by decreasing the uncertainty of discharge-measurement frequency, or building an artificial control that would have a stable stage-discharge relation over time.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27810747','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27810747"><span>Evaluating the impacts of climate and land-use change on the hydrology and nutrient yield in a transboundary river basin: A case study in the 3S River Basin (Sekong, Sesan, and Srepok).</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Trang, Nguyen Thi Thuy; Shrestha, Sangam; Shrestha, Manish; Datta, Avishek; Kawasaki, Akiyuki</p> <p>2017-01-15</p> <p>Assessment of the climate and land-use change impacts on the hydrology and water quality of a river basin is important for the development and management of water resources in the future. The objective of this study was to examine the impact of climate and land-use change on the hydrological regime and nutrient yield from the 3S River Basin (Sekong, Srepok, and Sesan) into the 3S River system in Southeast Asia. The 3S Rivers are important tributaries of the Lower Mekong River, accounting for 16% of its annual flow. This transboundary basin supports the livelihoods of nearly 3.5 million people in the countries of Laos, Vietnam, and Cambodia. To reach a better understanding of the process and fate of pollution (nutrient yield) as well as the hydrological regime, the Soil and Water Assessment Tool (SWAT) was used to simulate water quality and discharge in the 3S River Basin. Future scenarios were developed for three future periods: 2030s (2015-2039), 2060s (2045-2069), and 2090s (2075-2099), using an ensemble of five GCMs (General Circulation Model) simulations: (HadGEM2-AO, CanESM2, IPSL-CM5A-LR, CNRM-CM5, and MPI-ESM-MR), driven by the climate projection for RCPs (Representative Concentration Pathways): RCP4.5 (medium emission) and RCP8.5 (high emission) scenarios, and two land-use change scenarios. The results indicated that the climate in the study area would generally become warmer and wetter under both emission scenarios. Discharge and nutrient yield is predicted to increase in the wet season and decrease in the dry. Overall, the annual discharge and nutrient yield is projected to increase throughout the twenty-first century, suggesting sensitivity in the 3S River Basin to climate and land-use change. The results of this study can assist water resources managers and planners in developing water management strategies for uncertain climate change scenarios in the 3S River Basin. Copyright © 2016 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/0644f/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/0644f/report.pdf"><span>History of Snake River Canyon Indicated by Revised Stratigraphy of Snake River Group Near Hagerman and King Hill, Idaho: With a Section on Paleomagnetism</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Malde, Harold E.; Cox, Allan</p> <p>1971-01-01</p> <p>A discovery that debris left by the Bonneville Flood (Melon Gravel) overlies McKinney Basalt about 200 feet above the Snake River near King Hill requires that the stratigraphy of the Snake River Group be revised. In former usage, the McKinney Basalt and its immediately older companion, the Wendell Grade Basalt, were considered on the basis of equivocal field relations to be younger than the Melon Gravel and were assigned to the Recent. These lava flows are here reclassified as Pleistocene. The Bancroft Springs Basalt, which consists of both subaerial lava and pillow lava in a former Snake River canyon, was previously separated from the McKinney but is now combined with the McKinney. Accordingly, the name Bancroft Springs Basalt is here abandoned. This revised stratigraphy is first described from geomorphic relations of the McKinney Basalt near King Hill and is then discussed in the light of drainage changes caused by local lava flows during entrenchment of the Snake River. Near King Hill, a former Snake River canyon was completely filled by McKinney Basalt at the place called Bancroft Springs, hut the depth of this lava in the next several miles of the canyon downstream (along a route that approximately coincides with the present canyon) steadily decreased. This ancestral geomorphology is inferred from the former canyon route and, also, from the continuity in gradient of the McKinney lava surface downstream from Bancroft Springs. The drainage history recorded by various lava flows and river deposits of the Snake River Group indicates that the McKinney and Wendell Grade Basalts erupted after the Snake River canyon had reached its present depth of about 500 feet. The Snake River of that time, as far downstream as Bliss, flowed approximately along its present route. The Wood River of that time, however, skirted the north flank of Gooding Butte and joined the ancestral Snake at a junction, now concealed by lava, north of the present canyon about 3 miles west of Bliss. From that place the former Snake River canyon, also now concealed by lava, continued west to Bancroft Springs and thence along a route close to the present canyon to King Hill. To become entrenched in a canyon 500 feet deep, the Snake River downstream from Hagerman became progressively more incised while its upstream route was pushed south in several earlier canyons by intermittent lava flows. Distinctive gravel deposits help to establish the episodes of progressive canyon cutting and to determine the routes of ancestral drainage, including the former position of the Wood River. As canyon cutting continued, springs began to emerge where lavas had filled the earlier canyons. When the Snake River canyon eventually attained its approximate present depth, the Wendell Grade Basalt erupted near Shoshone and, as several tongues, spread west to the canyon rim opposite Hagerman. One tongue crossed the future route of the Wood River, and another covered an upland area of Sand Springs Basalt that had previously reached the canyon floor at Hagerman. The McKinney Basalt then erupted from McKinney Butte northeast of Bliss and spread southward as a subaerial flow, covering part of the Wendell Grade Basalt. It filled the ancestral Wood River canyon and the Snake River canyon of that time west of Bliss as far downstream as King Hill. The resulting dam of lava impounded a deep lake, which extended upstream in the canyon beyond Hagerman. Copious amounts of the McKinney spilled into this temporary lake and produced pillow lava. About 2 miles west of Bliss, pillow lava 500 feet thick completely fills the former canyon and is protected by rimrock of the subaerial McKinney Basalt. From Bliss, the pillow facies extends upstream as far as the McKinney rimrock - about 5 miles. Eruption of the McKinney Basalt diverted the Wood River to a course along the southeast edge of this lava flow. The temporary lake that was dammed by McKinney Basalt west of Bliss spilled along the sou</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC51E1134H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC51E1134H"><span>Analysis of Future Streamflow Regimes under Global Change Scenarios in Central Chile for Ecosystem Sustainability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Henriquez Dole, L. E.; Gironas, J. A.; Vicuna, S.</p> <p>2015-12-01</p> <p>Given the critical role of the streamflow regime for ecosystem sustainability, modeling long term effects of climate change and land use change on streamflow is important to predict possible impacts in stream ecosystems. Because flow duration curves are largely used to characterize the streamflow regime and define indices of ecosystem health, they were used to represent and analyze in this study the stream regime in the Maipo River Basin in Central Chile. Water and Environmental Assessment and Planning (WEAP) model and the Plant Growth Model (PGM) were used to simulate water distribution, consumption in rural areas and stream flows on a weekly basis. Historical data (1990-2014), future land use scenarios (2030/2050) and climate change scenarios were included in the process. Historical data show a declining trend in flows mainly by unprecedented climatic conditions, increasing interest among users on future streamflow scenarios. In the future, under an expected decline in water availability coupled with changes in crop water demand, water users will be forced to adapt by changing water allocation rules. Such adaptation actions would in turns affect the streamflow regime. Future scenarios for streamflow regime show dramatic changes in water availability and temporal distribution. Annual weekly mean flows can reduce in 19% in the worst scenario and increase in 3.3% in the best of them, and variability in streamflow increases nearly 90% in all scenarios under evaluation. The occurrence of maximum and minimum monthly flows changes, as June instead of July becomes the driest month, and December instead of January becomes the month with maximum flows. Overall, results show that under future scenarios streamflow is affected and altered by water allocation rules to satisfy water demands, and thus decisions will need to consider the streamflow regime (and habitat) in order to be sustainable.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1811914Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1811914Z"><span>Hydrological controls on Chemical weathering in the Jinsha River draining the southeastern Qinghai-Tibet Plateau</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhong, Jun; Li, Siliang; Yue, Fujun; Ding, Hu</p> <p>2016-04-01</p> <p>The geochemistry of the riverine waters could provide an insight in understanding the surface processes, such as chemical weathering and carbon cycle. As the headwater of Chanjiang (Yangtze) River, Jinsha River flows on the southestern Qinhai-Tibet Plateau at high altitute (from 1000m to 4600m) above the major areas of human impact and carries important information on this erosive region. In spite of being impacted by monsoonal climate and with significant variations of discharge, the temporal variations of compositions of main ions and chemical weathering of Jinsha River are rarely documented. In this study, a systematic investigation on the seasonal and episodic water geochemistry (major ions and δ13CDIC) of the outlet of Jinsha River basin were carried out with the purpose of 1) characterizing temporal variations of aqueous geochemistry and its controlling factors, 2) quantifying rock weathering and associated CO2 consumption rates, and 3) exploring the impact of hydrological controls on chemical weathering of the Jinsha River Basin. The results show that the concentrations of Ca, Mg, HCO3 and NO3 are generally decreased during monsoon season, while that of Cl, Na, SO4, K are relative higher in monsoon season than in dry season, which may be mainly caused by hydrological condition, i.e., with increased runoff, more surficial evaporate dissolved water and salt lake water of the Basin flow into the river. Moreover, due to increased contribution of soil CO2and fast decomposition of organic matters, δ13CDIC in the high-flow period has more negative values than in low-flow period, and shows a negative relation with the concentration of DOC. An increasing of Ca concentrations was found with shift of the δ13CDIC values, positively, indicating the precipitation might be occured. Meanwhile, the dissolution of gypsum and anhydrite might enhance the calcium precipition. The forward model results show that the weathering rates of silicate and carbonate as well as that of related CO2 consumption have a positive relation with water discharge, highlighting the hydrological controls on chemical weathering and CO2 consumption rates, which should be considered in the future study in river basins impacted by monsoon climate. This work was supported by The China National Science Fund for Outstanding Young Scholars (Grant No. 41422303).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/1492/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/1492/report.pdf"><span>Debris flows from tributaries of the Colorado River, Grand Canyon National Park, Arizona</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Webb, Robert H.; Pringle, Patrick T.; Rink, Glenn R.</p> <p>1989-01-01</p> <p>A reconnaissance of 36 tributaries of the Colorado River indicates that debris flows are a major process by which sediment is transported to the Colorado River in Grand Canyon National Park. Debris flows are slurries of sediment and water that have a water content of less than about 40 percent by volume. Debris flows occur frequently in arid and semiarid regions. Slope failures commonly trigger debris flows, which can originate from any rock formation in the Grand Canyon. The largest and most frequent flows originate from the Permian Hermit Shale, the underlying Esplanade Sandstone of the Supai Group, and other formations of the Permian and Pennsylvanian Supai Group. Debris flows also occur in the Cambrian Muav Limestone and underlying Bright Angel Shale and the Quaternary basalts in the western Grand Canyon. Debris-flow frequency and magnitude were studied in detail in the Lava-Chuar Creek drainage at Colorado River mile 65.5; in the Monument Creek drainage at mile 93.5; and in the Crystal Creek drainage at mile 98.2. Debris flows have reached the Colorado River on an average of once every 20 to 30 years in the Lava-Chuar Creek drainage since about 1916. Two debris flows have reached the Colorado River in the last 25 years in Monument Creek. The Crystal Creek drainage has had an average of one debris flow reaching the Colorado River every 50 years, although the debris flow of 1966 has been the only flow that reached the Colorado River since 1900. Debris flows may actually reach the Colorado River more frequently in these drainages because evidence for all debris flows may not have been preserved in the channel-margin stratigraphy. Discharges were estimated for the peak flow of three debris flows that reached the Colorado River. The debris flow of 1966 in the Lava-Chuar Creek drainage had an estimated discharge of 4,000 cubic feet per second. The debris flow of 1984 in the Monument Creek drainage had a discharge estimated between 3,600 and 4,200 cubic feet per second. The debris flow of 1966 in the Crystal Creek drainage had a discharge estimated between 9,200 and 14,000 cubic feet per second. Determination of the effective cross-sectional area was a problem in all calculations involving superelevations on bends because areas near superelevation marks were 1.5 to 3.5 times larger than areas of upstream or downstream cross sections. Debris flows in the Grand Canyon generally are composed of 10 to 40 percent sand by weight and may represent a significant source of beach-building sand along the Colorado River. The particle-size distributions are very poorly sorted and the largest transported boulders were in the Crystal Creek drainage. The large boulders transported into the Colorado River by debris flows create or change hydraulic controls (rapids); these controls appear to be governed by the magnitude and frequency of tributary-flow events and the history of discharges on the Colorado River. Reworking of debris fans by the Colorado River creates debris bars that constrain the size of eddy systems and forms secondary rapids and riffles below tributary mouths.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JHyd..552..351Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JHyd..552..351Z"><span>Calculating e-flow using UAV and ground monitoring</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, C. S.; Zhang, C. B.; Yang, S. T.; Liu, C. M.; Xiang, H.; Sun, Y.; Yang, Z. Y.; Zhang, Y.; Yu, X. Y.; Shao, N. F.; Yu, Q.</p> <p>2017-09-01</p> <p>Intense human activity has led to serious degradation of basin water ecosystems and severe reduction in the river flow available for aquatic biota. As an important water ecosystem index, environmental flows (e-flows) are crucial for maintaining sustainability. However, most e-flow measurement methods involve long cycles, low efficiency, and transdisciplinary expertise. This makes it impossible to rapidly assess river e-flows at basin or larger scales. This study presents a new method to rapidly assessing e-flows coupling UAV and ground monitorings. UAV was firstly used to calculate river-course cross-sections with high-resolution stereoscopic images. A dominance index was then used to identify key fish species. Afterwards a habitat suitability index, along with biodiversity and integrity indices, was used to determine an appropriate flow velocity with full consideration of the fish spawning period. The cross-sections and flow velocity values were then combined into AEHRA, an e-flow assessment method for studying e-flows and supplying-rate. To verify the results from this new method, the widely used Tennant method was employed. The root-mean-square errors of river cross-sections determined by UAV are less than 0.25 m, which constitutes 3-5% water-depth of the river cross-sections. In the study area of Jinan city, the ecological flow velocity (VE) is equal to or greater than 0.11 m/s, and the ecological water depth (HE) is greater than 0.8 m. The river ecosystem is healthy with the minimum e-flow requirements being always met when it is close to large rivers, which is beneficial for the sustainable development of the water ecosystem. In the south river channel of Jinan, the upstream flow mostly meets the minimum e-flow requirements, and the downstream flow always meets the minimum e-flow requirements. The north of Jinan consists predominantly of artificial river channels used for irrigation. Rainfall rarely meets the minimum e-flow and irrigation water requirements. We suggest that the water shortage problem can be partly solved by diversion of the Yellow River. These results can provide useful information for ecological operations and restoration. The method used in this study for calculating e-flow based on a combination of UAV and ground monitoring can effectively promote research progress into basin e-flow, and provide an important reference for e-flow monitoring around the world.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.H21E1222M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.H21E1222M"><span>Evaluation of potential impacts of climate change and water management on streamflow in the Rovuma River, Mozambique and Tanzania</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Minihane, M.; Lettenmaier, D. P.</p> <p>2012-12-01</p> <p>Economic development and public health are tied to water resources development in many parts of the world. Effective use of water management infrastructure investments requires projections of future climatic and water use conditions. This is particularly true in developing countries. We explore in this work water resource availability in the Rovuma River, which lies in a sparsely-populated region of southeastern Africa, on the border of Mozambique and Tanzania. While there are only limited documented observations of flow of the Rovuma River and it's tributaries, particularly in recent years, there is widespread interest in development of the water resources of the region. The national governments are interested in hydropower potential while private companies, many of them large multinational organizations, have started irrigation programs to increase agricultural output. While the Mozambique and Tanzania governments have a joint agreement over the river development, there is a need to assess both current and potential future water resource conditions in the basin. The sustainability of these developments, however, may be affected by climate change. Here we quantify potential changes in streamflow in the Rovuma River under dry and wet climate projection scenarios using the delta method and the Variable Infiltration Capacity (VIC) macro-scale hydrology model. We then evaluate streamflow changes relative to water withdrawals required for a range of irrigated agriculture scenarios. Our analysis is intended to be a starting point for planners to consider potential impacts of both streamflow withdrawal permits (for irrigated agriculture) and future uncertain climate conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28692899','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28692899"><span>Many-objective robust decision making for water allocation under climate change.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yan, Dan; Ludwig, Fulco; Huang, He Qing; Werners, Saskia E</p> <p>2017-12-31</p> <p>Water allocation is facing profound challenges due to climate change uncertainties. To identify adaptive water allocation strategies that are robust to climate change uncertainties, a model framework combining many-objective robust decision making and biophysical modeling is developed for large rivers. The framework was applied to the Pearl River basin (PRB), China where sufficient flow to the delta is required to reduce saltwater intrusion in the dry season. Before identifying and assessing robust water allocation plans for the future, the performance of ten state-of-the-art MOEAs (multi-objective evolutionary algorithms) is evaluated for the water allocation problem in the PRB. The Borg multi-objective evolutionary algorithm (Borg MOEA), which is a self-adaptive optimization algorithm, has the best performance during the historical periods. Therefore it is selected to generate new water allocation plans for the future (2079-2099). This study shows that robust decision making using carefully selected MOEAs can help limit saltwater intrusion in the Pearl River Delta. However, the framework could perform poorly due to larger than expected climate change impacts on water availability. Results also show that subjective design choices from the researchers and/or water managers could potentially affect the ability of the model framework, and cause the most robust water allocation plans to fail under future climate change. Developing robust allocation plans in a river basin suffering from increasing water shortage requires the researchers and water managers to well characterize future climate change of the study regions and vulnerabilities of their tools. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H53N..05D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H53N..05D"><span>Water quality under increased biofuel production and future climate change and uncertainty</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Demissie, Y. K.; Yan, E.</p> <p>2015-12-01</p> <p>Over the past decade, biofuel has emerged as an important renewable energy source to supplement gasoline and reduce the associated greenhouse gas emission. Many countries, for instant, have adopted biofuel production goals to blend 10% or more of gasoline with biofuels within 10 to 20 years. However, meeting these goals requires sustainable production of biofuel feedstock which can be challenging under future change in climate and extreme weather conditions, as well as the likely impacts of biofuel feedstock production on water quality and availability. To understand this interrelationship and the combined effects of increased biofuel production and climate change on regional and local water resources, we have performed watershed hydrology and water quality analyses for the Ohio River Basin. The basin is one of the major biofuel feedstock producing region in the United States, which also currently contributes about half of the flow and one third of phosphorus and nitrogen loadings to the Mississippi River that eventually flows to the Gulf of Mexico. The analyses integrate future scenarios and climate change and biofuel development through various mixes of landuse and agricultural management changes and examine their potential impacts on regional and local hydrology, water quality, soil erosion, and agriculture productivity. The results of the study are expected to provide much needed insight about the sustainability of large-scale biofuel feedstock production under the future climate change and uncertainty, and helps to further optimize the feedstock production taking into consideration the water-use efficiency.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2008/3038/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2008/3038/"><span>Providing Data and Modeling to Help Manage Water Supplies</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nickles, James</p> <p>2008-01-01</p> <p>The Sonoma County Water Agency (SCWA) and other local water purveyors have partnered with the U.S. Geological Survey (USGS) to assess hydrologic conditions and to quan-tify the county-wide interconnections between surface water and ground water. Through this partnership, USGS scientists have completed assessments of the geohydrology and geochemistry of the Sonoma and Alexander Valley ground-water basins. Now, the USGS is constructing a detailed ground-water flow model of the Santa Rosa Plain. It will be used to help identify strategies for surface-water/ground-water management and help to ensure long-term viability of the water supply. The USGS is also working with the SCWA to help meet future demand in the face of possible new restrictions on its main source of water, the Russian River. SCWA draws water from the alluvial aquifer underlying and adjacent to the Russian River and may want to extend riverbank filtration facilities to new areas. USGS scientists are conducting research to charac-terize riverbank filtration processes and changes in water quality during reduced river flows.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25461048','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25461048"><span>An ecological economic assessment of flow regimes in a hydropower dominated river basin: the case of the lower Zambezi River, Mozambique.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fanaian, Safa; Graas, Susan; Jiang, Yong; van der Zaag, Pieter</p> <p>2015-02-01</p> <p>The flow regime of rivers, being an integral part of aquatic ecosystems, provides many important services benefiting humans in catchments. Past water resource developments characterized by river embankments and dams, however, were often dominated by one (or few) economic use(s) of water. This results in a dramatically changed flow regime negatively affecting the provision of other ecosystem services sustained by the river flow. This study is intended to demonstrate the value of alternative flow regimes in a river that is highly modified by the presence of large hydropower dams and reservoirs, explicitly accounting for a broad range of flow-dependent ecosystem services. In this study, we propose a holistic approach for conducting an ecological economic assessment of a river's flow regime. This integrates recent advances in the conceptualization and classification of ecosystem services (UK NEA, 2011) with the flow regime evaluation technique developed by Korsgaard (2006). This integrated approach allows for a systematic comparison of the economic values of alternative flow regimes, including those that are considered beneficial for aquatic ecosystems. As an illustration, we applied this combined approach to the Lower Zambezi Basin, Mozambique. Empirical analysis shows that even though re-operating dams to create environmentally friendly flow regimes reduces hydropower benefits, the gains to goods derived from the aquatic ecosystem may offset the forgone hydropower benefits, thereby increasing the total economic value of river flow to society. The proposed integrated flow assessment approach can be a useful tool for welfare-improving decision-making in managing river basins. Copyright © 2014 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H53B1691R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H53B1691R"><span>Effects of climate change on water abstraction restrictions for irrigation during droughts - The UK case</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rey Vicario, D.; Holman, I.</p> <p>2016-12-01</p> <p>The use of water for irrigation and on-farm reservoir filling is globally important for agricultural production. In humid climates, like the UK, supplemental irrigation can be critical to buffer the effects of rainfall variability and to achieve high quality crops. Given regulatory efforts to secure sufficient environmental river flows and meet rising water demands due to population growth and climate change, increasing water scarcity is likely to compound the drought challenges faced by irrigated agriculture in this region. Currently, water abstraction from surface waters for agricultural irrigation can be restricted by the Environment Agency during droughts under Section 57 of the Water Resources Act (1991), based on abnormally low river flow levels and rainfall forecast, causing significant economic impacts on irrigated agricultural production. The aim of this study is to assess the impact that climate change may have on agricultural abstraction in the UK within the context of the abstraction restriction triggers currently in place. These triggers have been applied to the `Future Flows hydrology' database to assess the likelihood of increasing restrictions on agricultural abstraction in the future by comparing the probability of voluntary and compulsory restrictions in the baseline (1961-1990) and future period (2071-2098) for 282 catchments throughout the whole of the UK. The results of this study show a general increase in the probability of future agricultural irrigation abstraction restrictions in the UK in the summer, particularly in the South West, although there is significant variability between the 11 ensemble members. The results also indicate that UK winters are likely to become wetter in the future, although in some catchments the probability of abstraction restriction in the reservoir refilling winter months (November-February) could increase slightly. An increasing frequency of drought events due to climate change is therefore likely to lead to more water abstraction restrictions, increasing the need for irrigators to adapt their businesses to increase drought resilience and hence food security.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70107102','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70107102"><span>Combined impacts of current and future dust deposition and regional warming on Colorado River Basin snow dynamics and hydrology</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Deems, Jeffrey S.; Painter, Thomas H.; Barsugli, Joseph J.; Belnap, Jayne; Udall, Bradley</p> <p>2013-01-01</p> <p>The Colorado River provides water to 40 million people in seven western states and two countries and to 5.5 million irrigated acres. The river has long been overallocated. Climate models project runoff losses of 5–20% from the basin by mid-21st century due to human-induced climate change. Recent work has shown that decreased snow albedo from anthropogenic dust loading to the CO mountains shortens the duration of snow cover by several weeks relative to conditions prior to western expansion of the US in the mid-1800s, and advances peak runoff at Lees Ferry, Arizona, by an average of 3 weeks. Increases in evapotranspiration from earlier exposure of soils and germination of plants have been estimated to decrease annual runoff by more than 1.0 billion cubic meters, or ~5% of the annual average. This prior work was based on observed dust loadings during 2005–2008; however, 2009 and 2010 saw unprecedented levels of dust loading on snowpacks in the Upper Colorado River Basin (UCRB), being on the order of 5 times the 2005–2008 loading. Building on our prior work, we developed a new snow albedo decay parameterization based on observations in 2009/10 to mimic the radiative forcing of extreme dust deposition. We convolve low, moderate, and extreme dust/snow albedos with both historic climate forcing and two future climate scenarios via a delta method perturbation of historic records. Compared to moderate dust, extreme dust absorbs 2× to 4× the solar radiation, and shifts peak snowmelt an additional 3 weeks earlier to a total of 6 weeks earlier than pre-disturbance. The extreme dust scenario reduces annual flow volume an additional 1% (6% compared to pre-disturbance), a smaller difference than from low to moderate dust scenarios due to melt season shifting into a season of lower evaporative demand. The sensitivity of flow timing to dust radiative forcing of snow albedo is maintained under future climate scenarios, but the sensitivity of flow volume reductions decreases with increased climate forcing. These results have implications for water management and suggest that dust abatement efforts could be an important component of any climate adaptation strategies in the UCRB.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H52D..01G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H52D..01G"><span>Seasonal Dynamics of River Corridor Exchange Across the Continental United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gomez-Velez, J. D.; Harvey, J. W.; Scott, D.; Boyer, E. W.; Schmadel, N. M.</p> <p>2017-12-01</p> <p>River corridors store and convey mass and energy from landscapes to the ocean, altering water quality and ecosystem functioning at the local, reach, and watershed scales. As water moves through river corridors from headwaters streams to coastal estuaries, dynamic exchange between the river channel and its adjacent riparian, floodplain, and hyporheic zones, combined with ponded waters such as lakes and reservoirs, results in the emergence of hot spots and moments for biogeochemical transformations. In this work, we used the model Networks with EXchange and Subsurface Storage (NEXSS) to estimate seasonal variations in river corridor exchange fluxes and residence times along the continental United States. Using a simple routing scheme, we translate these estimates into a cumulative measure of river corridor connectivity at the watershed scale, differentiating the contributions of hyporheic zones, floodplains, and ponded waters. We find that the relative role of these exchange subsystems changes seasonally, driven by the intra-seasonal variability of discharge. In addition, we find that seasonal variations in discharge and the biogeochemical potential of hyporheic zones are out of phase. This behavior results in a significant reduction in hyporheic water quality functions during high flows and emphasizes the potential importance of reconnecting floodplains for managing water quality during seasonal high flows. Physical parameterizations of river corridor processes are critical to model and predict water quality and to sustainably manage water resources under present and future socio-economic and climatic conditions. Parsimonious models like NEXSS can play a key role in the design, implementation, and evaluation of sustainable management practices that target both water quantity and quality at the scale of the nation. This research is a product of the John Wesley Powell Center River Corridor Working Group.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.2389I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.2389I"><span>Tagliamento, the king of Alpine rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Imbriani, Nadia</p> <p>2016-04-01</p> <p>The Tagliamento river is usually described as the king of the Alpine rivers because it is an extraordinary example of braided gravel-bed river in Europe. It flows in Friuli Venezia Giulia, a region in north-eastern Italy. It has preserved its original ecosystem which has never been changed significantly by irresponsible human interference. Therefore, vegetated islands and braid bars, due to the typical network of channels the river creates, have always been an uncontaminated natural habitat for a wide variety of species of flora and fauna. The Pinzano Bridge, near San Daniele del Friuli, collapsed on 4th November 1966 because of an overflow of water from Tagliamento. From that time, lowlands territorial authorities would like to build retention basins to prevent the river from floodings. A study about the bio-geological survey carried out from a Manzini High School project, chiefly aims to study this ecosystem, which combines the dynamic nature of the Tagliamento with the biodiversity of the whole area where it flows. In the previous years, some classes were involved in this school project. After visiting the river area and taking several photographs of it, the students had the opportunity to reflect upon the devastating environmental impact which the construction of retention basins would cause. They illustrated and analyzed both the solutions offered by some local governors and the objections raised by the World Wide Fund For Nature (WWF). In the near future, other students will continue studying the Tagliamento river so as to be able to appreciate one of the local rarities nature offers, in the hope that the unique geomorphological features of this site of undoubted scientific interest could be kept intact for a very long time.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/1342089-turbine-control-tidal-river-power-generator','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1342089-turbine-control-tidal-river-power-generator"><span>Turbine Control of a Tidal and River Power Generator</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Muljadi, Eduard; Wright, Alan; Gevorgian, Vahan</p> <p></p> <p>As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded to include new types with promising future applications, such as river and tidal generation. The input variations to these types of resources are slower but also steadier than wind or solar generation. The level of water turbulent flow may vary from one place to another, however, the control algorithm can be adjusted to local environment. This paper describes the hydrokinetic aspects of river and tidal generation based on a river and tidal generator. Althoughmore » the information given in this paper is not that of an exact generator deployed on site, the data used is representative of a typical river or tidal generator. In this paper, the hydrokinetic and associated electrical controller of the system were not included; however, the focus of this paper is on the hydrodynamic control.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1311352','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1311352"><span>Turbine Control of a Tidal and River Power Generator: Preprint</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Muljadi, Eduard; Gevorgian, Vahan; Wright, Alan</p> <p></p> <p>As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded to include new types with promising future applications, such as river and tidal generation. The input variations to these types of resources are slower but also steadier than wind or solar generation. The level of water turbulent flow may vary from one place to another, however, the control algorithm can be adjusted to local environment. This paper describes the hydrokinetic aspects of river and tidal generation based on a river and tidal generator. Althoughmore » the information given in this paper is not that of an exact generator deployed on site, the data used is representative of a typical river or tidal generator. In this paper, the hydrokinetic and associated electrical controller of the system were not included; however, the focus of this paper is on the hydrodynamic control.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018IJEaS.107..103H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018IJEaS.107..103H"><span>Porous media of the Red River Formation, Williston Basin, North Dakota: a possible Sedimentary Enhanced Geothermal System</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hartig, Caitlin M.</p> <p>2018-01-01</p> <p>Fracture-stimulated enhanced geothermal systems (EGS) can be developed in both crystalline rocks and sedimentary basins. The Red River Formation (Ordovician) is a viable site for development of a sedimentary EGS (SEGS) because the formation temperatures exceed 140 °C and the permeability is 0.1-38 mD; fracture stimulation can be utilized to improve permeability. The spatial variations of the properties of the Red River Formation were analyzed across the study area in order to understand the distribution of subsurface formation temperatures. Maps of the properties of the Red River Formation-including depth to the top of the formation, depth to the bottom of the formation, porosity, geothermal gradient, heat flow, and temperature-were produced by the Kriging interpolation method in ArcGIS. In the future, these results may be utilized to create a reservoir simulation model of an SEGS in the Red River Formation; the purpose of this model would be to ascertain the thermal response of the reservoir to fracture stimulation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JIEIA..94...43P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JIEIA..94...43P"><span>Informed Decision Making Process for Managing Environmental Flows in Small River Basins</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Padikkal, S.; Rema, K. P.</p> <p>2013-03-01</p> <p>Numerous examples exist worldwide of partial or complete alteration to the natural flow regime of river systems as a consequence of large scale water abstraction from upstream reaches. The effects may not be conspicuous in the case of very large rivers, but the ecosystems of smaller rivers or streams may be completely destroyed over a period of time. While restoration of the natural flow regime may not be possible, at present there is increased effort to implement restoration by regulating environmental flow. This study investigates the development of an environmental flow management model at an icon site in the small river basin of Bharathapuzha, west India. To determine optimal environmental flow regimes, a historic flow model based on data assimilated since 1978 indicated a satisfactory minimum flow depth for river ecosystem sustenance is 0.907 m (28.8 m3/s), a value also obtained from the hydraulic model; however, as three of the reservoirs were already operational at this time a flow depth of 0.922 m is considered a more viable estimate. Analysis of daily stream flow in 1997-2006, indicated adequate flow regimes during the monsoons in June-November, but that sections of the river dried out in December-May with alarming water quality conditions near the river mouth. Furthermore, the preferred minimum `dream' flow regime expressed by stakeholders of the region is a water depth of 1.548 m, which exceeds 50 % of the flood discharge in July. Water could potentially be conserved for environmental flow purposes by (1) the de-siltation of existing reservoirs or (2) reducing water spillage in the transfer between river basins. Ultimately environmental flow management of the region requires the establishment of a co-ordinated management body and the regular assimilation of water flow information from which science based decisions are made, to ensure both economic and environmental concerns are adequately addressed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.1083L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.1083L"><span>Data analysis and hydrological modelling of frozen ground, shallow groundwater formation and river flow co-evolution at small watersheds of Russia in continuous, discontinuous permafrost and the zone of seasonal ground freezing</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lebedeva, Luidmila; Semenova, Olga</p> <p>2015-04-01</p> <p>Frozen ground distribution and its properties control the presence of aquifuge and aquifers. Correct representation of interactions between infiltrating water, ground ice, permafrost or seasonal freezing table and river flow is challenging for hydrological modelling in cold regions. Observational data of ground water levels, thawing depths in different landscapes or topographical units and meteorological information with high temporal and spatial resolution are required to analyze seasonal and interannual evolution of groundwater in active layer and its linkage to river flow. Such data are extremely rare in vast and remote regions of Russia. There are few historical datasets inherited from former USSR containing unique collection of long-term daily observations of water fluxes, frozen ground characteristics and groundwater levels. The data from three water balance stations were employed in our study with overall goal to analyze co-evolution of thawing layer, shallow groundwater and river flow by data processing and process-based modelling. Three instrumented small watersheds are situated in continuous, discontinuous permafrost zones and at the territory with seasonally frozen ground. They present different climates, landscapes and geology. The Kolyma water-balance station is located in mountainous region of continuous permafrost in North-Eastern Russia. The watershed area of 22 km2 is covered by bare rocks, mountain tundra, sparse larch forest and wet larch forest depending on slope aspect and inclination. The Bomnak water-balance station (22 km2) is situated in discontinuous permafrost zone in upper part of the Amur River basin and characterized by unmerged permafrost. Dominant landscapes are birch forest and bogs. The Pribaltiyskaya water-balance station (40 km2) located in Latvia is characterized by seasonally frozen ground and is covered by mixed forest and arable land. Process-based Hydrograph model was employed in the study. The model was developed specifically for cold regions. It describes all essential processes of land hydrological cycle including detailed algorithm of water and heat dynamics in soil accounting for water phase change. The model parameters relate to basin characteristics and could be assessed in the field. It allows avoiding parameters calibration and transferring model parameterization schemes to ungauged basins in similar conditions. The model was applied and tested against internal states of watersheds (snow, soil thawing/freezing, etc.) and runoff. Different role of frozen ground in formation of shallow groundwater and river flow in continuous, discontinuous and non-permafrost area is highlighted by comparative analysis of observations and simulations in three studied basins. The changes of fractional input of surface and subsurface components into river flow during warm seasons were assessed for each watershed. We concluded that verified hydrological model with meaningful parameters that adequately describe river flow formation and internal hydrological processes and ground freezing/thawing in the catchment could be used in scenario simulations, future predictions and transferring the results between scales.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19..664S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19..664S"><span>40Ar/39Ar mica dating of late Cenozoic sediments in the upper Yangtze: Implications for sediment provenance and drainage evolution</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Xilin; Li, Chang'an; Kuiper, Kuiper; Zhang, Zengjie; Wijbrans, Jan</p> <p>2017-04-01</p> <p>The development of the river systems in East Asia is closely linked to the uplift of the Tibetan plateau caused by collision of the India-Eurasia. The Yangtze River is the largest river in Asia and the timing and exact causes of its formation are still a matter of debate. Controversy exists for example on the start of the connection of the eastern Tibetan rivers to the eastward flowing Yangtze instead of the southward flowing Red River. Here we use the 40Ar/39Ar dating of detrital micas (muscovite and biotite) and muscovite geochemistry to constrain the sediment provenance in the eastern Tibetan Plateau. The remarkable spatial and temporal variation in sediment provenance allow us to extract information about the evolution of the upper Yangtze River. The combined data suggest that the upper Jinsha River upstream from Shigu town lost its connection with the southward flowing Red River at least earlier than the Pliocene. To the east of Shigu, the Yalong and Jinsha rivers flowed across the Yuanmou Basin into the Red River before 3.1 Ma, but abandoned this connection and turned east somewhere between 3.1 and 2.1 Ma. Our results rule out the possibility of a west-flowing Jinsha River since 1.58 Ma. The current stream directions between Shigu and Panzhihua go north, south and east and must have been formed at that time. Our data also shed new light on the evolution of the Dadu River. The Dadu River did not flow southward into Yuanmou Basin at least since 4.8 Ma but flowed into the Jinsha River along the Anninghe Fault. These capture events are closely linked to the tectonism of the eastern Tibetan Plateau and intensification of the East Asia monsoon.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMEP41C1849B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMEP41C1849B"><span>Floodplain Connectivity and implications for flooding and floodplain function</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barrow, E.</p> <p>2017-12-01</p> <p>Regime theory suggests that floodplains should be inundated on average once every two years to maintain form and function of both the river and the floodplain. Natural disconnection along non-alluvial reaches and where the river has moved to flow against terrace edges is to be expected, however, disconnectivity caused by river management is now affecting increasing lengths of watercourses. This study utilises aerial Lidar data to determine the relative height difference between the watercourse and adjacent valley bottoms to assess the degree of disconnectivity along main river systems across Cumbria in the UK. The results reveal that many rivers are now poorly connected to their floodplains which are now largely non-functional. Floodplain geomorphic units, although often present, are currently inactive and water table levels are reduced resulting in a loss of wetland in favour of ruderal species tolerant of drier conditions. The causes of such widespread disconnectivity may be attributed to historic dredging and straightening of these rivers and revetment and riparian tree planting has further exacerbated the problem restricting lateral activity and the subsequent development of new areas of connected floodplain. The high degree of disconnection has implications for future river management and river restoration and these are discussed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC53A1191H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC53A1191H"><span>Seasonal Response of Overland Flow and Sediment Loading to Climate and Land Use Land Cover Change in the Apalachicola River, Florida</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hovenga, P. A.; Wang, D.; Medeiros, S. C.; Hagen, S. C.</p> <p>2015-12-01</p> <p>Located in Florida's panhandle, the Apalachicola River is the southernmost reach of the Apalachicola-Chattahoochee-Flint (ACF) River basin. Streamflow and sediment drains to Apalachicola Bay within the Northern Gulf of Mexico, resulting in a direct influence on the ecology of the region, in particular seagrass and oyster production. This study examines the seasonal response of overland flow and sediment loading in the Apalachicola River under projected climate change scenarios and land use land cover (LULC) change. A hydrologic model using the Soil Water Assessment Tool (SWAT) was developed for the Apalachicola region to simulate daily discharge and sediment load under present (circa 2000) and future conditions (circa 2100) to understand how parameters respond over a seasonal time frame to changes in climate only, LULC only, and coupled climate / LULC. These physically-based models incorporate digital elevation model (DEM), LULC, soil maps, climate data, and management controls. Long Ashton Research Station-Weather Generator (LARS-WG) was used to create stochastic temperature and precipitation inputs from four Global Climate Models (GCM), each under Intergovernmental Panel on Climate Change (IPCC) carbon emission scenarios for A1B, A2, and B1. These scenarios represent potential future emissions resulting from a range driving forces, e.g. social, economic, environmental, and technologic. Projected 2100 LULC data provided by the United States Geological Survey (USGS) EROS Center was incorporated for each corresponding IPCC scenario. Results from this study can be used to further understand climate and LULC implications to the Apalachicola Bay and surrounding region as well as similar fluvial estuaries while providing tools to better guide management and mitigation practices.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/wri034086/pdf/wri034086.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/wri034086/pdf/wri034086.pdf"><span>Changes in streamflow and summary of major-ion chemistry and loads in the North Fork Red River basin upstream from Lake Altus, northwestern Texas and western Oklahoma, 1945-1999</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Smith, S. Jerrod; Wahl, Kenneth L.</p> <p>2003-01-01</p> <p>Upstream from Lake Altus, the North Fork Red River drains an area of 2,515 square miles. The quantity and quality of surface water are major concerns at Lake Altus, and water-resource managers and consumers need historical information to make informed decisions about future development. The Lugert-Altus Irrigation District relies on withdrawals from the lake to sustain nearly 46,000 acres of agricultural land. Kendall's tau tests of precipitation data indicated no statistically significant trend over the entire 100 years of available record. However, a significant increase in precipitation occurred in the last 51 years. Four streamflow-gaging stations with more than 10 years of record were maintained in the basin. These stations recorded no significant trends in annual streamflow volume. Two stations, however, had significant increasing trends in the base-flow index, and three had significant decreasing trends in annual peak flows. Major-ion chemistry in the North Fork Red River is closely related to the chemical composition of the underlying bedrock. Two main lithologies are represented in the basin upstream from Lake Altus. In the upper reaches, young and poorly consolidated sediments include a range of sizes from coarse gravel to silt and clay. Nearsurface horizons commonly are cemented as calcium carbonate caliche. Finer-grained gypsiferous sandstones and shales dominate the lower reaches of the basin. A distinct increase in dissolved solids, specifically sodium, chloride, calcium, and sulfate, occurs as the river flows over rocks that contain substantial quantities of gypsum, anhydrite, and dolomite. These natural salts are the major dissolved constituents in the North Fork Red River.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70157192','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70157192"><span>The effect of channel shape, bed morphology, and shipwrecks on flow velocities in the Upper St. Clair River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Czuba, Jonathan A.; Oberg, Kevin; Best, Jim; Parsons, Daniel R.</p> <p>2009-01-01</p> <p>In the Great Lakes of North America, the St. Clair River is the major outlet of Lake Huron and conveys water to Lake St. Clair which then flows to Lake Erie. One major topic of interest is morphological change in the St. Clair River and its impact on water levels in the Upper Great Lakes and connecting channel flows. A combined multibeam echosounder (MBES) bathymetric survey and acoustic Doppler current profiler (ADCP) flow survey of the outlet of Lake Huron and the Upper St. Clair River was conducted July 21 – 25, 2008. This paper presents how channel morphology and shipwrecks affect the flow in the Upper St. Clair River. The river is most constricted at the Blue Water Bridge near Port Huron, Michigan, with water velocities over 2 ms-1 for a flow of 5,200 m3s-1. Downstream of this constriction, the river flows around a bend and expands creating a large recirculation zone along the left bank due to flow separation. This recirculation zone reduces the effective channel width, and thus increases flow velocities to over 2 ms-1 in this region. The surveys reveal several shipwrecks on the bed of the St. Clair River, which possess distinct wakes in their flow velocity downstream of the wrecks. The constriction and expansion of the channel, combined with forcing of the flow by bed topography, initiates channel-scale secondary flow, creating streamwise vortices that maintain coherence downstream over a distance of several channel widths.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1051105','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1051105"><span>Planning for the Future: Why the U.S. Navy Needs a Separate Strategy and Plans Community</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2018-04-09</p> <p>change decisively. They are like a great river that maintains its course, but adjusts its flow.” – Sun Tzu NOP v. Navy Strategy – Similarities...36 BIBLIOGRAPHY ...January 2016), 9. 3 Ibid, 9. 38 BIBLIOGRAPHY Air University. “School of Advanced Air and Space Studies,” http://www.airuniversity.af.mil/SAASS</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1813810L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1813810L"><span>Salinity trends in the Ebro River (Spain)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lorenzo-Gonzalez, M.° Angeles; Isidoro, Daniel; Quilez, Dolores</p> <p>2016-04-01</p> <p>In the Ebro River Basin (Spain), the increase in water diversion for irrigation (following the increase in irrigated area) and the recovery of natural vegetation in the upper reaches, along with climate change have induced changes in the river flow and its associated salt loads. This study was supported by the Ebro River Basin Administration (CHE) and aimed to establish the trends in the salt concentrations and loads of the Ebro River at Tortosa (no 027, the extreme downstream gauging station). The CHE databases from 1972-73 to 2011-12, including mean monthly flows (Q) and concentration readings (electrical conductivity converted to total dissolved solids -TDS- by regression) from monthly grab samples, have been used. The trends were established by (i) harmonic regression analysis; (ii) linear regression by month; and (iii) the non-parametric Mann-Kendall method. Additionally, (iv) the regressions of TDS on Q in the current and previous months were established, allowing for analyzing separately the trends in TDS linked to- (TDSq) and independent of- (TDSaj) the observed changes in flow. In all cases, the trends were analyzed for different periods within the full span 1973-2012 (1973 to 2012, 1981 to 2012, 1990-2012 and 2001-2012), trying to account for periods with sensibly similar patterns of land use change. An increase in TDS was found for all the periods analyzed that was lower as shorter periods were used, suggesting that lower salinity changes might be taking place in the last years, possibly due to the reduction in the rate of irrigation development and to the on-going irrigation modernization process. The higher seasonal TDS increases were found in autumn and winter months and the increase in TDS was linked both to intrinsic changes in salinity (TDSaj) and to the observed decrease in flow (TDSq). On the other hand, the salt loads decreased, especially in autumn, as a result of the observed flow decrease. These results are based on the observed evolution of flows and salinity in 1973-2012 and can only be extrapolated into the future if the drivers of this evolution (climate and land use changes) remain unchanged in the following years, what is uncertain. A more comprehensive methodology to estimate the effects of irrigation on water salinity has been developed based on a mass balance approach. Using actual data on volumes and concentrations of return flows observed in the basin (dependent on the actual salinity of soils and waters and the irrigation systems, among other factors), the return flows of the irrigated areas are aggregated to match the actual flows and loads observed in the Ebro River. Once this balance is satisfied, the effect of new irrigated areas, drainage water reuse, irrigation modernization, or climate change would be incorporated to the balance yielding salinity forecasts based on planned irrigation developments and modernization or climate change predictions. A priori, irrigation modernization would produce lower, more concentrated volumes of return flows with lower salt loads that would result in lower TDS concentrations in the Ebro River.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/preview/wri/wri014002/pdf/wrir014002_ver3.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/preview/wri/wri014002/pdf/wrir014002_ver3.pdf"><span>Simulation of ground-water flow in the Mojave River basin, California</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stamos, Christina L.; Martin, Peter; Nishikawa, Tracy; Cox, Brett F.</p> <p>2001-01-01</p> <p>The proximity of the Mojave River ground-water basin to the highly urbanized Los Angeles region has led to rapid growth in population and, consequently, to an increase in the demand for water. The Mojave River, the primary source of surface water for the region, normally is dry-except for a small stretch of perennial flow and periods of flow after intense storms. Thus, the region relies almost entirely on ground water to meet its agricultural and municipal needs. Ground-water withdrawal since the late 1800's has resulted in discharge, primarily from pumping wells, that exceeds natural recharge. To better understand the relation between the regional and the floodplain aquifer systems and to develop a management tool that could be used to estimate the effects that future stresses may have on the ground-water system, a numerical ground-water flow model of the Mojave River ground-water basin was developed, in part, on the basis of a previously developed analog model. The ground-water flow model has two horizontal layers; the top layer (layer 1) corresponds to the floodplain aquifer and the bottom layer (layer 2) corresponds to the regional aquifer. There are 161 rows and 200 columns with a horizontal grid spacing of 2,000 by 2,000 feet. Two stress periods (wet and dry) per year are used where the duration of each stress period is a function of the occurrence, quantity of discharge, and length of stormflow from the headwaters each year. A steady-state model provided initial conditions for the transient-state simulation. The model was calibrated to transient-state conditions (1931-94) using a trial-and-error approach. The transient-state simulation results are in good agreement with measured data. Under transient-state conditions, the simulated floodplain aquifer and regional aquifer hydrographs matched the general trends observed for the measured water levels. The simulated streamflow hydrographs matched wet stress period average flow rates and times of no flow at the Barstow and Afton Canyon gages. Steady-state particle-tracking was used to estimate travel times for mountain-front and streamflow recharge. The simulated travel times for mountain-front recharge to reach the area west of Victorville were about 5,000 to 6,000 years; this result is in reasonable agreement with published results. Steady-state particle-tracking results for streamflow recharge indicate that in most subareas along the river, the particles quickly leave and reenter the river. The complaint that resulted in the adjudication of the Mojave River ground-water basin alleged that the cumulative water production upstream of the city of Barstow had overdrafted the ground-water basin. In order to ascertain the effect of pumping on ground-water and surface-water relations along the Mojave River, two pumping simulations were compared with the 1931-90 transient-state simulation (base case). The first simulation assumed 1931-90 pumping in the upper region (Este, Oeste, Alto, and Transition zone model subareas) but with no pumping in the remainder of the basin, and the second assumed 1931-90 pumping in the lower region (Centro, Harper Lake, Baja, Coyote Lake, and Afton Canyon model subareas) but with no pumping in remainder of the basin. In the upper region, assuming pumping only in the upper region, there was no change in storage, recharge from the Mojave River, ground-water discharge to the Mojave River, or evapotranspiration when compared with the base case. In the lower region, assuming pumping only in the upper region, there was storage accretion, decreased recharge from the Mojave River, increased ground-water discharge to the Mojave River, and increased evapotranspiration when compared with the base case. In the upper region, assuming pumping only in the lower region, there was storage accretion, decreased recharge from the Mojave River, increased ground-water discharge to the Mojave River, and increased evapotranspiration when compared with the base case. In the</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70043345','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70043345"><span>Effects of drought on birds and riparian vegetation in the Colorado River Delta, Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hinojosa-Huerta, Osvel; Nagler, Pamela L.; Carrillo-Guererro, Yamilett K.; Glenn, Edward P.</p> <p>2013-01-01</p> <p>The riparian corridor in the delta of the Colorado River in Mexico supports internationally important bird habitat. The vegetation is maintained by surface flows from the U.S. and Mexico and by a high, non-saline aquifer into which the dominant phreatophytic shrubs and trees are rooted. We studied the effects of a regional drought on riparian vegetation and avian abundance and diversity from 2002 to 2007, during which time surface flows were markedly reduced compared to the period from 1995 to 2002. Reduced surface flows led to a reduction in native tree cover but an increase in shrub cover, mostly due to an increase in Tamarix spp., an introduced halophytic shrub, and a reduction in Populus fremontii and Salix gooddingii trees. However, overall vegetation cover was unchanged at about 70%. Overall bird density and diversity were also unchanged, but riparian-obligate species tended to decrease in abundance, and generalist species increased. Although reduction in surface flows reduced habitat value and negatively impacted riparian-obligate bird species, portions of the riparian zone exhibited resilience. Surface flows are required to reduce soil salt levels and germinate new cohorts of native trees, but the main source of water supporting this ecosystem is the aquifer, derived from underflows from irrigated fields in the U.S. and Mexico. The long-term prospects for delta riparian habitats are uncertain due to expected reduced flows of river water from climate change, and land use practices that will reduce underflows to the riparian aquifer and increase salinity levels. Active restoration programs would be needed if these habitats are to be preserved for the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H41D0835K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H41D0835K"><span>Modeling the Effects of Land Use and Climate Change on Streamflow in the Delaware River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwon, P. Y. S.; Endreny, T. A.; Kroll, C. N.; Williamson, T. N.</p> <p>2014-12-01</p> <p>Forest-cover loss and drinking-water reservoirs in the upper Delaware River Basin of New York may alter summer low streamflows, which could degrade the in-stream habitat for the endangered dwarf wedgemussel. Our project analyzes how flow statistics change with land-cover change for 30-year increments of model-simulated streamflow hydrographs for three watersheds of concern to the National Park Service: the East Branch, West Branch, and main stem of the Delaware River. We use four treatments for land cover ranging from historical high to low forest cover. We subject each land cover to adjusted GCM climate scenarios for 1600, 1900, 1940, and 2040 to isolate land cover from potential climate-change effects. Hydrographs are simulated using the Water Availability Tool for Environmental Resources (WATER), a TOPMODEL-based United States Geological Survey hydrologic decision-support tool, which uses the variable-source-area concept and water budgets to generate streamflow. Model parameters for each watershed change with land-use, and capture differences in soil-physical properties that control how rainfall infiltrates, evaporates, transpires, is stored in the soil, and moves to the stream. Our results analyze flow statistics used as indicators of hydrologic alteration, and access streamflow events below the critical flow needed to provide sustainable habitat for dwarf wedgemussels. These metrics will demonstrate how changes in climate and land use might affect flow statistics. Initial results show that the 1940 WATER simulation outputs generally match observed unregulated low flows from that time period, while performance for regulated flow from the same time period and from 1600, 1900, and 2040 require model input adjustments. Our study will illustrate how increased forest cover could potentially restore in-stream habitat for the endangered dwarf wedgemussel for current and future climate conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170005236&hterms=budget&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbudget','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170005236&hterms=budget&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbudget"><span>Evaluating LSM-Based Water Budgets Over a West African Basin Assisted with a River Routing Scheme</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Getirana, Augusto C. V.; Boone, Aaron; Peugeot, Christophe</p> <p>2014-01-01</p> <p>Within the framework of the African Monsoon Multidisciplinary Analysis (AMMA) Land Surface Model Intercomparison Project phase 2 (ALMIP-2), this study evaluates the water balance simulated by the Interactions between Soil, Biosphere, and Atmosphere (ISBA) over the upper Oum River basin, in Benin, using a mesoscale river routing scheme (RRS). The RRS is based on the nonlinear Muskingum Cunge method coupled with two linear reservoirs that simulate the time delay of both surface runoff and base flow that are produced by land surface models. On the basis of the evidence of a deep water-table recharge in that region,a reservoir representing the deep-water infiltration (DWI) is introduced. The hydrological processes of the basin are simulated for the 2005-08 AMMA field campaign period during which rainfall and stream flow data were intensively collected over the study area. Optimal RRS parameter sets were determined for three optimization experiments that were performed using daily stream flow at five gauges within the basin. Results demonstrate that the RRS simulates stream flow at all gauges with relative errors varying from -22% to 3% and Nash-Sutcliffe coefficients varying from 0.62 to 0.90. DWI varies from 24% to 67% of the base flow as a function of the sub-basin. The relatively simple reservoir DWI approach is quite robust, and further improvements would likely necessitate more complex solutions (e.g., considering seasonality and soil type in ISBA); thus, such modifications are recommended for future studies. Although the evaluation shows that the simulated stream flows are generally satisfactory, further field investigations are necessary to confirm some of the model assumptions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23694971','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23694971"><span>Braided river flow and invasive vegetation dynamics in the Southern Alps, New Zealand.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Caruso, Brian S; Edmondson, Laura; Pithie, Callum</p> <p>2013-07-01</p> <p>In mountain braided rivers, extreme flow variability, floods and high flow pulses are fundamental elements of natural flow regimes and drivers of floodplain processes, understanding of which is essential for management and restoration. This study evaluated flow dynamics and invasive vegetation characteristics and changes in the Ahuriri River, a free-flowing braided, gravel-bed river in the Southern Alps of New Zealand's South Island. Sixty-seven flow metrics based on indicators of hydrologic alteration and environmental flow components (extreme low flows, low flows, high flow pulses, small floods and large floods) were analyzed using a 48-year flow record. Changes in the areal cover of floodplain and invasive vegetation classes and patch characteristics over 20 years (1991-2011) were quantified using five sets of aerial photographs, and the correlation between flow metrics and cover changes were evaluated. The river exhibits considerable hydrologic variability characteristic of mountain braided rivers, with large variation in floods and other flow regime metrics. The flow regime, including flood and high flow pulses, has variable effects on floodplain invasive vegetation, and creates dynamic patch mosaics that demonstrate the concepts of a shifting mosaic steady state and biogeomorphic succession. As much as 25 % of the vegetation cover was removed by the largest flood on record (570 m(3)/s, ~50-year return period), with preferential removal of lupin and less removal of willow. However, most of the vegetation regenerated and spread relatively quickly after floods. Some flow metrics analyzed were highly correlated with vegetation cover, and key metrics included the peak magnitude of the largest flood, flood frequency, and time since the last flood in the interval between photos. These metrics provided a simple multiple regression model of invasive vegetation cover in the aerial photos evaluated. Our analysis of relationships among flow regimes and invasive vegetation cover has implications for braided rivers impacted by hydroelectric power production, where increases in invasive vegetation cover are typically greater than in unimpacted rivers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25003149','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25003149"><span>Improvement of water quality at Dongbin Harbor with construction of an inland canal, Korea.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cho, Yong-Sik</p> <p>2014-01-01</p> <p>The behaviors of the water body of Dongbin Harbor located at Pohang City, Gyongpook Province, in Korea were numerically simulated in this study. A canal was planned to connect the harbor and the Hyeongsan River to improve water quality inside the harbor. The current system was first simulated by using a commercial program RMA2, with respect to both tidal currents and river flow. The progress inside the harbor from a supply of fresh water from the Hyeongsan River was then predicted by using RMA4. Both the present and future conditions (before and after construction of an inland canal) were taken into consideration in numerical simulations. It is concluded that the water quality inside the harbor can be improved considerably after construction of the canal.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.jstor.org/stable/41717320','USGSPUBS'); return false;" href="http://www.jstor.org/stable/41717320"><span>Beaver herbivory of willow under two flow regimes: A comparative study on the Green and Yampa rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Breck, Stewart W.; Wilson, Kenneth R.; Andersen, Douglas C.</p> <p>2003-01-01</p> <p>The effect of flow regulation on plant-herbivore ecology has received very little attention, despite the fact that flow regulation can alter both plant and animal abundance and environmental factors that mediate interactions between them. To determine how regulated flows have impacted beaver (Castor canadensis) and sandbar willow (Salix exigua) ecology, we first quantified the abundance and mapped the spatial distribution of sandbar willow on alluvial sections of the flow-regulated Green River and free-flowing Yampa River in northwestern Colorado. We then established 16 and 15 plots (1 m × 2.7 m) in patches of willow on the Green and Yampa Rivers, respectively, to determine whether rates of beaver herbivory of willow differed between rivers (Green versus Yampa River), seasons (fall-winter versus spring-summer), and years (spring 1998-spring 1999 versus spring 1999-spring 2000). Areal extent of willow was similar on each river, but Green River willow patches were smaller and more numerous. Beavers cut more stems during fall and winter than spring and summer and cut over 6 times more stems (percentage basis) on the Green River than on the Yampa River. We attribute the between-river difference in herbivory to higher availability of willow, greater beaver density, and lower availability of young Fremont cottonwood (Populus deltoides subsp. wislizenii; an alternative food source) on the Green River. Flow regulation increased willow availability to beaver by promoting the formation of island patches that are continuously adjacent to water and feature a perimeter with a relatively high proportion of willow interfacing with water.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1995/4110/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1995/4110/report.pdf"><span>Quantity and quality of ground-water discharge to the South Platte River, Denver to Fort Lupton, Colorado, August 1992 through July 1993</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McMahon, P.B.; Lull, K.J.; Dennehy, K.F.; Collins, J.A.</p> <p>1995-01-01</p> <p>Water-quality studies conducted by the Metro Wastewater Reclamation District have indicated that during low flow in segments of the South Platte River between Denver and Fort Lupton, concentrations of dissolved oxygen are less than minimum concen- trations set by the State of Colorado. Low dissolved-oxygen concentrations are observed in two reaches of the river-they are about 3.3 to 6.4 miles and 17 to 25 miles downstream from the Metro Waste- water Reclamation District effluent outfalls. Concentrations of dissolved oxygen recover between these two reaches. Studies conducted by the U.S. Geological Survey have indicated that ground-water discharge to the river may contribute to these low dissolved-oxygen concentrations. As a result, an assessment was made of the quantity and quality of ground-water discharge to the South Platte River from Denver to Fort Lupton. Measurements of surface- water and ground-water discharge and collections of surface water and ground water for water-quality analyses were made from August 1992 through January 1993 and in May and July 1993. The quantity of ground-water discharge to the South Platte River was determined indirectly by mass balance of surface-water inflows and outflows and directly by instantaneous measurements of ground-water discharge across the sediment/water interface in the river channel. The quality of surface water and ground water was determined by sampling and analysis of water from the river and monitoring wells screened in the alluvial aquifer adjacent to the river and by sampling and analysis of water from piezometers screened in sediments underlying the river channel. The ground-water flow system was subdivided into a large-area and a small-area flow system. The precise boundaries of the two flow systems are not known. However, the large-area flow system is considered to incorporate all alluvial sediments in hydrologic connection with the South Platte River. The small- area flow system is considered to incorporate the alluvial aquifer in the vicinity of the river. Flow-path lengths in the large-area flow system were considered to be on the order of hundreds of feet to more than a mile, whereas in the small-area flow system, they were considered to be on the order of feet to hundreds of feet. Mass-balance estimates of incremental ground-water discharge from the large- area flow system ranged from -27 to 17 cubic feet per second per mile in three reaches of the river; the median rate was 4.6 cubic feet per second per mile. The median percentage of surface-water discharge derived from ground-water discharge in the river reaches studied was 13 percent. Instantaneous measurements of ground-water discharge from the small-area flow system ranged from -1,360 to 1,000 cubic feet per second per mile, with a median value of -5.8 cubic feet per second per mile. Hourly measurements of discharge from the small-area flow system indicated that the high rates of discharge were transient and may have been caused by daily fluctuations in river stage due to changing effluent-discharge rates from the Metro Wastewater Reclamation District treatment plant. Higher river stages caused surface water to infiltrate bed sediments underlying the river channel, and lower river stages allowed ground water to discharge into the river. Although stage changes apparently cycled large quantities of water in and out of the small- area flow system, the process probably provided no net gain or loss of water to the river. In general, mass balance and instantaneous measurements of ground-water discharge indicated that the ground- water flow system in the vicinity of the river consisted of a large-area flow system that provided a net addition of water to the river and a small- area flow system that cycled water in and out of the riverbed sediments, but provided no net addition of water to the river. The small-area flow system was superimposed on the large-area flow system. The median values of pH and dissolved oxygen</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.water.usgs.gov/wri034204/','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/wri034204/"><span>Watershed analysis of the Salmon River watershed, Washington : hydrology</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bidlake, William R.</p> <p>2003-01-01</p> <p>The U.S. Geological Survey analyzed selected hydrologic conditions as part of a watershed analysis of the Salmon River watershed, Washington, conducted by the Quinault Indian Nation. The selected hydrologic conditions were analyzed according to a framework of hydrologic key questions that were identified for the watershed. The key questions were posed to better understand the natural, physical, and biological features of the watershed that control hydrologic responses; to better understand current streamflow characteristics, including peak and low flows; to describe any evidence that forest harvesting and road construction have altered frequency and magnitude of peak and low flows within the watershed; to describe what is currently known about the distribution and extent of wetlands and any impacts of land management activities on wetlands; and to describe how hydrologic monitoring within the watershed might help to detect future hydrologic change, to preserve critical ecosystem functions, and to protect public and private property.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70175000','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70175000"><span>Western water and climate change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dettinger, Michael; Udall, Bradley; Georgakakos, Aris P.</p> <p>2015-01-01</p> <p>In this context, four iconic river basins offer glimpses into specific challenges that climate change may bring to the West. The Colorado River is a system in which overuse and growing demands are projected to be even more challenging than climate-change-induced flow reductions. The Rio Grande offers the best example of how climate-change-induced flow declines might sink a major system into permanent drought. The Klamath is currently projected to face the more benign precipitation future, but fisheries and irrigation management may face dire straits due to warming air temperatures, rising irrigation demands, and warming waters in a basin already hobbled by tensions between endangered fisheries and agricultural demands. Finally, California's Bay-Delta system is a remarkably localized and severe weakness at the heart of the region's trillion-dollar economy. It is threatened by the full range of potential climate-change impacts expected across the West, along with major vulnerabilities to increased flooding and rising sea levels.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC41G..04L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC41G..04L"><span>Global Assessment of Exploitable Surface Reservoir Storage under Climate Change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, L.; Parkinson, S.; Gidden, M.; Byers, E.; Satoh, Y.; Riahi, K.</p> <p>2016-12-01</p> <p>Surface water reservoirs provide us with reliable water supply systems, hydropower generation, flood control, and recreation services. Reliable reservoirs can be robust measures for water security and can help smooth out challenging seasonal variability of river flows. Yet, reservoirs also cause flow fragmentation in rivers and can lead to flooding of upstream areas, thereby displacing existing land-uses and ecosystems. The anticipated population growth, land use and climate change in many regions globally suggest a critical need to assess the potential for appropriate reservoir capacity that can balance rising demands with long-term water security. In this research, we assessed exploitable reservoir potential under climate change and human development constraints by deriving storage-yield relationships for 235 river basins globally. The storage-yield relationships map the amount of storage capacity required to meet a given water demand based on a 30-year inflow sequence. Runoff data is simulated with an ensemble of Global Hydrological Models (GHMs) for each of five bias-corrected general circulation models (GCMs) under four climate change pathways. These data are used to define future 30-year inflows in each river basin for time period between 2010 and 2080. The calculated capacity is then combined with geographical information of environmental and human development exclusion zones to further limit the storage capacity expansion potential in each basin. We investigated the reliability of reservoir potentials across different climate change scenarios and Shared Socioeconomic Pathways (SSPs) to identify river basins where reservoir expansion will be particularly challenging. Preliminary results suggest large disparities in reservoir potential across basins: some basins have already approached exploitable reserves, while some others display abundant potential. Exclusions zones pose significant impact on the amount of actual exploitable storage and firm yields worldwide: 30% of reservoir potential would be unavailable because of land occupation by environmental and human development. Results from this study will help decision makers to understand the reliability of infrastructure systems particularly sensitive to future water availability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2006/5212/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2006/5212/"><span>An assessment of flow data from Klamath River sites between Link River Dam and Keno Dam, south-central Oregon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Risley, John C.; Hess, Glen W.; Fisher, Bruce J.</p> <p>2006-01-01</p> <p>Records of diversion and return flows for water years 1961?2004 along a reach of the Klamath River between Link River and Keno Dams in south-central Oregon were evaluated to determine the cause of a water-balance inconsistency in the hydrologic data. The data indicated that the reach was losing flow in the 1960s and 1970s and gaining flow in the 1980s and 1990s. The absolute mean annual net water-balance difference in flows between the first and second half of the 44-year period (1961-2004) was approximately 103,000 acre-feet per year (acre-ft/yr). The quality of the diversion and return-flow records used in the water balance was evaluated using U.S. Geological Survey (USGS) criteria for accuracy. With the exception of the USGS Klamath River at Keno record, which was rated as 'good' or 'excellent,' the eight other flow records, all from non-USGS flow-measurement sites, were rated as 'poor' by USGS standards due to insufficient data-collection documentation and a lack of direct discharge measurements to verify the rating curves. The record for the Link River site, the most upstream in the study area, included both river and westside power canal flows. Because of rating curve biases, the river flows might have been overestimated by 25,000 acre-ft/yr on average from water years 1961 to 1982 and underestimated by 7,000 acre-ft/yr on average from water years 1983 to 2004. For water years 1984-2004, westside power canal flows might have been underestimated by 11,000 acre-ft/yr. Some diversion and return flows (for mostly agricultural, industrial, and urban use) along the Klamath River study reach, not measured continuously and not included in the water-balance equation, also were evaluated. However, the sum of these diversion and return flows was insufficient to explain the water-balance inconsistency. The possibility that ground-water levels in lands adjacent to the river rose during water years 1961-2004 and caused an increase in ground-water discharge to the river also was evaluated. However, water-level data from local wells did not have a rising trend during the period. The most likely cause of the water-balance inconsistency was flow measurement error in the eight non-USGS flow records. Part of the water-balance inconsistency can be explained by a 43,000 acre-foot error in the river and canal flow portions of the Link River flow record. A remaining 60,000 acre-foot error might have been distributed among the seven other flow records, or much of the remaining 60,000 acre-foot error might have been in the Link River flow record because flows in that record had a greater magnitude than flows in the seven other records. As an additional analysis of the water-balance issue, flow records used in the water balance were evaluated for trends and compared to known changes in water management in the Bureau of Reclamation Klamath Project and Lower Klamath and Tule Lake National Wildlife Refuges over the 44-year period. Many of the water-management changes were implemented in the early 1980s. For three diversion flow records, 1983-2004 mean annual flows were 16,000, 8,000, and 21,000 acre-ft/yr greater than their 1961-82 mean annual flows. Return flows to the Klamath River at two flow-measurement sites decreased by 31,000 and 27,000 acre-ft/yr for 1983-2004 compared with the 1961-82 period.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.esajournals.org/doi/abs/10.1890/10-1719.1','USGSPUBS'); return false;" href="http://www.esajournals.org/doi/abs/10.1890/10-1719.1"><span>Ecosystem ecology meets adaptive management: food web response to a controlled flood on the Colorado River, Glen Canyon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cross, Wyatt F.; Baxter, Colden V.; Donner, Kevin C.; Rosi-Marshall, Emma J.; Kennedy, Theodore A.; Hall, Robert O.; Wellard Kelly, Holly A.; Rogers, R. Scott</p> <p>2011-01-01</p> <p>Large dams have been constructed on rivers to meet human demands for water, electricity, navigation, and recreation. As a consequence, flow and temperature regimes have been altered, strongly affecting river food webs and ecosystem processes. Experimental high-flow dam releases, i.e., controlled floods, have been implemented on the Colorado River, USA, in an effort to reestablish pulsed flood events, redistribute sediments, improve conditions for native fishes, and increase understanding of how dam operations affect physical and biological processes. We quantified secondary production and organic matter flows in the food web below Glen Canyon dam for two years prior and one year after an experimental controlled flood in March 2008. Invertebrate biomass and secondary production declined significantly following the flood (total biomass, 55% decline; total production, 56% decline), with most of the decline driven by reductions in two nonnative invertebrate taxa, Potamopyrgus antipodarum and Gammarus lacustris. Diatoms dominated the trophic basis of invertebrate production before and after the controlled flood, and the largest organic matter flows were from diatoms to the three most productive invertebrate taxa (P. antipodarum, G. lacustris, and Tubificida). In contrast to invertebrates, production of rainbow trout (Oncorhynchus mykiss) increased substantially (194%) following the flood, despite the large decline in total secondary production of the invertebrate assemblage. This counterintuitive result is reconciled by a post-flood increase in production and drift concentrations of select invertebrate prey (i.e., Chironomidae and Simuliidae) that supported a large proportion of trout production but had relatively low secondary production. In addition, interaction strengths, measured as species impact values, were strongest between rainbow trout and these two taxa before and after the flood, demonstrating that the dominant consumer—resource interactions were not necessarily congruent with the dominant organic matter flows. Our study illustrates the value of detailed food web analysis for elucidating pathways by which dam management may alter production and strengths of species interactions in river food webs. We suggest that controlled floods may increase production of nonnative rainbow trout, and this information can be used to help guide future dam management decisions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H43D1677D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H43D1677D"><span>Trend and variability in western and central Africa streamflow, and major drivers of variability between 1950 and 2005</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dieppois, B.; Sidibe, M.; Mahe, G. M.; Paturel, J. E.; Anifowose, B. A.; Lawler, D.; Amoussou, E.</p> <p>2017-12-01</p> <p>Unprecedented drought episodes that struck western and central Africa between the late 1960s and 1980s, triggered many studies investigating rainfall variability and its impacts on water resources and food production systems. However, most studies were focused at the catchment scale. In this study, we aim at investigating the key large-scale controls determining and modulating climate-river flows relationships at the subcontinental scale between 1950 and 2005. Using the first complete monthly streamflow data set (1950-2005) over western and central Africa, streamflow trend and variability are seasonally assessed at this subcontinental scale and compared to those observed in other hydroclimatic variables (precipitation, temperature and potential evapotranspiration). Long-term trends and variability in streamflow are mainly consistent with trends in rainfall. In particular, the recent post-1990s partial recovery in Sahel rainfall could have, at least partially, positively impacted river flows (e.g. the Senegal and Niger rivers). However, these relationships may have been moderated by: i) changes in land use; and ii) contributions from groundwater resources. In addition, the time-evolution of river flows is shown to be primarily driven by very strong decadal fluctuations, which can be interpreted as modulations in the baseflow, as determined using multi-temporal trend and continuous wavelet analysis. These decadal fluctuations, which are also significantly detected in rainfall, are likely related to large-scale sea-surface temperature (SST) anomaly patterns (such as the tropical Atlantic SST variability, the Atlantic Multidecadal Oscillation, the Interdecadal Pacific Oscillation and the Pacific Decadal Oscillation), which are together modulating the West African monsoon. Furthermore, influences of the catchment properties (e.g. size, vegetation and land use cover, soil properties, direction of stream flow across climate zones) on these decadal fluctuations in river flows have been examined. This study therefore aims to improve the ability of current global to regional climate models to simulate such ranges of variability and understand regional hydroclimate, as a means for improving the development of future scenarios for water resources in western and central Africa.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70022243','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70022243"><span>Tree recruitment and survival in rivers: Influence of hydrological process</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dorava, J.M.; Milner, A.M.</p> <p>2000-01-01</p> <p>The findings of a 14-year study of tree reproduction and survival in the Platte River, Nebraska, are presented. The study was initiated in 1985 to determine the causes and remedies of woodland expansion and channel narrowing, which have reduced potential roosting habitat for migratory avifauna such as the whooping crane and sandhill crane. A total of 296 relocatable sites, constituting some 600 plots with Populus and Salix seedlings, was selected and sampled within two reaches near Shelton and Odessa, Nebraska. The fate of some 37 000 tree seedlings was monitored within the plot network. Tree recruitment is controlled largely by stream flow in June. Populus and Salix produce large numbers of seedlings in the river bed in most years, indicating the potential for high rates of woodland expansion. On average, in only 1 year in 7 is stream flow in June high enough to preclude Populus and Salix recruitment. Seedling mortality is dominated by two environmental factors: summer stream flow pulses from thunderstorms, which erode or bury new germinants, and river bed restructuring by moving ice in winter. A third factor, seedling mortality by desiccation during summer droughts, does occur but at a low frequency. Plots of seedlings had extremely low survival rates over the course of the study. Forty-two per cent of the plots lost all seedlings by the first remeasurement (July to September), 36% by the second measurement (May), and 10% by the third remeasurement (July). Thus nearly 90% of the plots had lost all tree seedlings by the end of the first year. These results explain why the Platte River has come into dynamic equilibrium with respect to the balance between active channel and woodland area. Low rates of new woodland expansion are counterbalanced by erosion of established woodland. The demographic approach to studying ecohydrology can be adapted to monitor the effectiveness of prescribed flows as insurance against future narrowing. Flows prescribed at key times to raise seedling mortality rates are recommended to maintain or widen channels, rather than mechanical clearing of established woodland. Copyright ?? 2000 John Wiley & Sons, Ltd.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000HyPr...14.3051C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000HyPr...14.3051C"><span>Tree recruitment and survival in rivers: influence of hydrological processes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carter Johnson, W.</p> <p>2000-10-01</p> <p>The findings of a 14-year study of tree reproduction and survival in the Platte River, Nebraska, are presented. The study was initiated in 1985 to determine the causes and remedies of woodland expansion and channel narrowing, which have reduced potential roosting habitat for migratory avifauna such as the whooping crane and sandhill crane.A total of 296 relocatable sites, constituting some 600 plots with Populus and Salix seedlings, was selected and sampled within two reaches near Shelton and Odessa, Nebraska. The fate of some 37 000 tree seedlings was monitored within the plot network.Tree recruitment is controlled largely by stream flow in June. Populus and Salix produce large numbers of seedlings in the river bed in most years, indicating the potential for high rates of woodland expansion. On average, in only 1 year in 7 is stream flow in June high enough to preclude Populus and Salix recruitment.Seedling mortality is dominated by two environmental factors: summer stream flow pulses from thunderstorms, which erode or bury new germinants, and river bed restructuring by moving ice in winter. A third factor, seedling mortality by desiccation during summer droughts, does occur but at a low frequency.Plots of seedlings had extremely low survival rates over the course of the study. Forty-two per cent of the plots lost all seedlings by the first remeasurement (July to September), 36% by the second measurement (May), and 10% by the third remeasurement (July). Thus nearly 90% of the plots had lost all tree seedlings by the end of the first year.</TD</TR<TR<TDThese results explain why the Platte River has come into dynamic equilibrium with respect to the balance between active channel and woodland area. Low rates of new woodland expansion are counterbalanced by erosion of established woodland.</TD</TR<TR<TDThe demographic approach to studying ecohydrology can be adapted to monitor the effectiveness of prescribed flows as insurance against future narrowing. Flows prescribed at key times to raise seedling mortality rates are recommended to maintain or widen channels, rather than mechanical clearing of established woodland. </TD</TR</TABLE</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMEP14C..05C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMEP14C..05C"><span>High Resolution Modelling of the Congo River's Multi-Threaded Main Stem Hydraulics</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carr, A. B.; Trigg, M.; Tshimanga, R.; Neal, J. C.; Borman, D.; Smith, M. W.; Bola, G.; Kabuya, P.; Mushie, C. A.; Tschumbu, C. L.</p> <p>2017-12-01</p> <p>We present the results of a summer 2017 field campaign by members of the Congo River users Hydraulics and Morphology (CRuHM) project, and a subsequent reach-scale hydraulic modelling study on the Congo's main stem. Sonar bathymetry, ADCP transects, and water surface elevation data have been collected along the Congo's heavily multi-threaded middle reach, which exhibits complex in-channel hydraulic processes that are not well understood. To model the entire basin's hydrodynamics, these in-channel hydraulic processes must be parameterised since it is not computationally feasible to represent them explicitly. Furthermore, recent research suggests that relative to other large global rivers, in-channel flows on the Congo represent a relatively large proportion of total flow through the river-floodplain system. We therefore regard sufficient representation of in-channel hydraulic processes as a Congo River hydrodynamic research priority. To enable explicit representation of in-channel hydraulics, we develop a reach-scale (70 km), high resolution hydraulic model. Simulation of flow through individual channel threads provides new information on flow depths and velocities, and will be used to inform the parameterisation of a broader basin-scale hydrodynamic model. The basin-scale model will ultimately be used to investigate floodplain fluxes, flood wave attenuation, and the impact of future hydrological change scenarios on basin hydrodynamics. This presentation will focus on the methodology we use to develop a reach-scale bathymetric DEM. The bathymetry of only a small proportion of channel threads can realistically be captured, necessitating some estimation of the bathymetry of channels not surveyed. We explore different approaches to this bathymetry estimation, and the extent to which it influences hydraulic model predictions. The CRuHM project is a consortium comprising the Universities of Kinshasa, Rhodes, Dar es Salaam, Bristol, and Leeds, and is funded by Royal Society-DFID Africa Capacity Building Initiative. The project aims to strengthen institutional research capacity and advance our understanding of the hydrology, hydrodynamics and sediment dynamics of the world's second largest river system through fieldwork and development of numerical models.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H41G1424D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H41G1424D"><span>Assessment of Ecosystem Services in a Semi-arid Agriculture-dominant Area: Framework and Case Study</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dhungel, R.; Chen, Y.; Maltos, R.; Sivakumaran, K.; Aguilar, A.; Harmon, T. C.</p> <p>2015-12-01</p> <p>California's Central Valley (CV) water crisis has increased in severity due to a prolonged drought. The drought is directly contributing to the overexploitation of groundwater, along with deficiency in agricultural, recreational and aesthetic water services. The population of the CV, home to about 6.5 million people, is projected to be 12 million by 2040. Balancing water demand between municipal use, agricultural supply, and other ecosystem services, will be challenging for this region in perpetuity. In the heart of CV lies the San Joaquin River (SJR) where Friant Dam is the main low-elevation reservoir regulating water release. The Friant Dam's reservoir fulfills agricultural, municipal and industrial water needs through the Friant-Kern and Madera canals, as well as through the mainstem SJR. The SJR restoration project (SJRRP) is a recent development that is imposing additional demands on water releases in order to restore sustainable aquatic habitat for Chinook salmon and other species on the mainstem below the Friant Dam. The Chinook require adequate flow to moderate river temperature, particularly during hot summer and fall months. Temperatures on CV rivers exhibit strong diurnal and seasonal patterns, and can rise to harmful levels when flows are inadequate. In this study, we developed a framework that allows for assessing the effectiveness and implied costs of ecosystem services provided by a restored SJR in a semi-arid agriculture-dominant area. This is done by explicitly linking economics-based farmers' model with a reduced-form hydrological model that is loosely coupled to a physical-based stream-temperature model, specifically CE-QUAL-W2. The farmers' model is based on positive mathematical program approach calibrated with twenty proxy crops for year 2005. The river-hydrology is simulated by a vector autoregression model that incorporates daily flow variability. We study the mandated release policies by the SJR restoration project, along with hypothetical policies aimed at moderating river temperatures while enhancing groundwater recharge along the river corridor. We hypothesize that agricultural losses in terms of flow diverted to the SJR restoration can be offset by gains in groundwater resources in a long run, which is important to reduce pumping costs and insure against future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JHyd..499..177L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JHyd..499..177L"><span>Integrating indigenous ecological and scientific hydro-geological knowledge using a Bayesian Network in the context of water resource development</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liedloff, A. C.; Woodward, E. L.; Harrington, G. A.; Jackson, S.</p> <p>2013-08-01</p> <p>The contributions indigenous ecological knowledge can make to better inform water management decisions are currently undervalued leading to an underrepresentation of indigenous values in water planning and policy. This paper outlines a novel approach in which indigenous ecological knowledge informs cause and effect relationships between species and aquatic habitats to promote broader ecosystem understanding. A Bayesian Network was developed to synthesise the seasonal aquatic knowledge of a group of Gooniyandi Aboriginal language speakers, including fish species’ availability, condition and required habitat, and integrate it with hydrogeological understanding obtained from research undertaken in a stretch of the Fitzroy River, Western Australia. This river system, like most in northern Australia, is highly seasonal and entirely dependent upon groundwater for maintaining flow during prolonged dry seasons. We found that potential changes in river flow rates caused by future water resource development, such as groundwater extraction and surface water diversion, may have detrimental effects on the ability to catch the high value aquatic food species such as Barramundi and Sawfish, but also that species such as Black Bream may benefit. These findings result from changes in availability of habitats at times when Gooniyandi understanding shows they are important for providing aquatic resources in good condition. This study raises awareness of the potential outcomes of future water management and stimulates communication between indigenous people, the scientific community and water managers by developing a model of indigenous understanding from which to predict eco-hydrological change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.9979W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.9979W"><span>Nutrient pollution mitigation measures across Europe are resilient under future climate</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wade, Andrew; Skeffington, Richard; Couture, Raoul; Erlandsson, Martin; Groot, Simon; Halliday, Sarah; Harezlak, Valesca; Hejzlar, Joseph; Jackson-Blake, Leah; Lepistö, Ahti; Papastergiadou, Eva; Psaltopoulos, Demetrios; Riera, Joan; Rankinen, Katri; Skuras, Dimitris; Trolle, Dennis; Whitehead, Paul; Dunn, Sarah; Bucak, Tuba</p> <p>2016-04-01</p> <p>The key results from the application of catchment-scale biophysical models to assess the likely effectiveness of nutrient pollution mitigation measures set in the context of projected land management and climate change are presented. The assessment is based on the synthesis of modelled outputs of daily river flow, river and lake nitrogen and phosphorus concentrations, and lake chlorophyll-a, for baseline (1981-2010) and scenario (2031-2060) periods for nine study sites across Europe. Together the nine sites represent a sample of key climate and land management types. The robustness and uncertainty in the daily, seasonal and long-term modelled outputs was assessed prior to the scenario runs. Credible scenarios of land-management changes were provided by social scientists and economists familiar with each study site, whilst likely mitigation measures were derived from local stakeholder consultations and cost-effectiveness assessments. Modelled mitigation options were able to reduce nutrient concentrations, and there was no evidence here that they were less effective under future climate. With less certainty, mitigation options could affect the ecological status of waters at these sites in a positive manner, leading to improvement in Water Framework Directive status at some sites. However, modelled outcomes for sites in southern Europe highlighted that increased evaporation and decreased precipitation will cause much lower flows leading to adverse impacts of river and lake ecology. Uncertainties in the climate models, as represented by three GCM-RCM combinations, did not affect this overall picture much.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2006/5213/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2006/5213/"><span>A Precipitation-Runoff Model for the Blackstone River Basin, Massachusetts and Rhode Island</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Barbaro, Jeffrey R.; Zarriello, Phillip J.</p> <p>2007-01-01</p> <p>A Hydrological Simulation Program-FORTRAN (HSPF) precipitation-runoff model of the Blackstone River Basin was developed and calibrated to study the effects of changing land- and water-use patterns on water resources. The 474.5 mi2 Blackstone River Basin in southeastern Massachusetts and northern Rhode Island is experiencing rapid population and commercial growth throughout much of its area. This growth and the corresponding changes in land-use patterns are increasing stress on water resources and raising concerns about the future availability of water to meet residential and commercial needs. Increased withdrawals and wastewater-return flows also could adversely affect aquatic habitat, water quality, and the recreational value of the streams in the basin. The Blackstone River Basin was represented by 19 hydrologic response units (HRUs): 17 types of pervious areas (PERLNDs) established from combinations of surficial geology, land-use categories, and the distribution of public water and public sewer systems, and two types of impervious areas (IMPLNDs). Wetlands were combined with open water and simulated as stream reaches that receive runoff from surrounding pervious and impervious areas. This approach was taken to achieve greater flexibility in calibrating evapotranspiration losses from wetlands during the growing season. The basin was segmented into 50 reaches (RCHRES) to represent junctions at tributaries, major lakes and reservoirs, and drainage areas to streamflow-gaging stations. Climatological, streamflow, water-withdrawal, and wastewater-return data were collected during the study to develop the HSPF model. Climatological data collected at Worcester Regional Airport in Worcester, Massachusetts and T.F. Green Airport in Warwick, Rhode Island, were used for model calibration. A total of 15 streamflow-gaging stations were used in the calibration. Streamflow was measured at eight continuous-record streamflow-gaging stations that are part of the U.S. Geological Survey cooperative streamflow-gaging network, and at seven partial-record stations installed in 2004 for this study. Because the model-calibration period preceded data collection at the partial-record stations, a continuous streamflow record was estimated at these stations by correlation with flows at nearby continuous-record stations to provide additional streamflow data for model calibration. Water-use information was compiled for 1996-2001 and included municipal and commercial/industrial withdrawals, private residential withdrawals, golf-course withdrawals, municipal wastewater-return flows, and on-site septic effluent return flows. Streamflow depletion was computed for all time-varying ground-water withdrawals prior to simulation. Water-use data were included in the model to represent the net effect of water use on simulated hydrographs. Consequently, the calibrated values of the hydrologic parameters better represent the hydrologic response of the basin to precipitation. The model was calibrated for 1997-2001 to coincide with the land-use and water-use data compiled for the study. Four long-term stations (Nipmuc River near Harrisville, Rhode Island; Quinsigamond River at North Grafton, Massachusetts; Branch River at Forestdale, Rhode Island; and Blackstone River at Woonsocket, Rhode Island) that monitor flow at 3.3, 5.4, 19, and 88 percent of the total basin area, respectively, provided the primary model-calibration points. Hydrographs, scatter plots, and flow-duration curves of observed and simulated discharges, along with various model-fit statistics, indicated that the model performed well over a range of hydrologic conditions. For example, the total runoff volume for the calibration period simulated at the Nipmuc River near Harrisville, Rhode Island; Quinsigamond River at North Grafton, Massachusetts; Branch River at Forestdale, Rhode Island; and Blackstone River at Woonsocket, Rhode Island streamflow-gaging stations differed from the observed runoff v</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhFl...28b1301S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhFl...28b1301S"><span>Sand waves in environmental flows: Insights gained by coupling large-eddy simulation with morphodynamics</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sotiropoulos, Fotis; Khosronejad, Ali</p> <p>2016-02-01</p> <p>Sand waves arise in subaqueous and Aeolian environments as the result of the complex interaction between turbulent flows and mobile sand beds. They occur across a wide range of spatial scales, evolve at temporal scales much slower than the integral scale of the transporting turbulent flow, dominate river morphodynamics, undermine streambank stability and infrastructure during flooding, and sculpt terrestrial and extraterrestrial landscapes. In this paper, we present the vision for our work over the last ten years, which has sought to develop computational tools capable of simulating the coupled interactions of sand waves with turbulence across the broad range of relevant scales: from small-scale ripples in laboratory flumes to mega-dunes in large rivers. We review the computational advances that have enabled us to simulate the genesis and long-term evolution of arbitrarily large and complex sand dunes in turbulent flows using large-eddy simulation and summarize numerous novel physical insights derived from our simulations. Our findings explain the role of turbulent sweeps in the near-bed region as the primary mechanism for destabilizing the sand bed, show that the seeds of the emergent structure in dune fields lie in the heterogeneity of the turbulence and bed shear stress fluctuations over the initially flatbed, and elucidate how large dunes at equilibrium give rise to energetic coherent structures and modify the spectra of turbulence. We also discuss future challenges and our vision for advancing a data-driven simulation-based engineering science approach for site-specific simulations of river flooding.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.H21C1072K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.H21C1072K"><span>Pore-Water Chemistry and Hydrology in a Spring-Fed River: Implications for Hyporheic Control of Nutrient Cycling and Speleogenesis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kurz, M. J.; Martin, J. B.; Cohen, M. J.</p> <p>2010-12-01</p> <p>Hyporheic exchange is important for nutrient cycling in rivers, but little is known about the magnitude of this process in karst systems or its influence on speleogenesis and the formation of river channels. We use four pore-water depth profiles to assess nutrient and carbonate processing in the hyporheic zone (HZ) of the Ichetucknee River (north-central, Florida). Co-located pairs of stilling wells equipped with conductivity, temperature, depth (CTD) sensors are used to continuously monitor the hydraulic gradients within the HZ to determine flow directions and temporal variability of groundwater exchange. The Ichetucknee River is sourced from six major and numerous small springs which discharge from the karstic Floridan Aquifer. Downstream and diel variations in nitrate concentrations, specific conductivity and calcite saturation state reflect in-stream processing, but hyporheic exchange should also influence the overall dynamics of nutrient and carbonate fluxes in the river. Our depth profiles and stilling wells are located at four sites in a cross-channel transect and extend through unconsolidated sediment to the solid carbonate of the Floridan Aquifer 35-156 cm below the river bed. Decreasing DOC, pH, and DO concentrations and increased DIC are indicative of organic carbon remineralization in the shallow sediments. Increasing alkalinity, Ca concentrations, specific conductivity and decreasing calcite saturation state indicate carbonate dissolution being driven by the decreasing pH. Decreasing nitrate concentrations indicate denitrification and increasing phosphate concentration could be a result of carbonate dissolution or OC remineralization. Most of these changes appear to occur in the upper 60cm of sediment, below which many concentrations return to values observed in the groundwater, suggesting water discharges from the Floridan Aquifer at the base of the sediment. Hydraulic head is higher in the pore waters than the river indicating groundwater then discharges to the river. Initial modeling of the system indicates that flow through the channel sediment moves horizontally and discharges into the river through the incised channel rather than upwards through the most reactive hyporheic sediments. While differences in chemical composition between the pore water and river water suggest the chemically altered pore water could affect chemical composition of the river it remains unclear the relative fractions of ground water and chemically altered pore water that flow into the river. Future work will attempt to quantify the magnitude of these exchanges over a range of hydrologic conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H52G..07C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H52G..07C"><span>A Robust Decision-Making Technique for Water Management under Decadal Scale Climate Variability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Callihan, L.; Zagona, E. A.; Rajagopalan, B.</p> <p>2013-12-01</p> <p>Robust decision making, a flexible and dynamic approach to managing water resources in light of deep uncertainties associated with climate variability at inter-annual to decadal time scales, is an analytical framework that detects when a system is in or approaching a vulnerable state. It provides decision makers the opportunity to implement strategies that both address the vulnerabilities and perform well over a wide range of plausible future scenarios. A strategy that performs acceptably over a wide range of possible future states is not likely to be optimal with respect to the actual future state. The degree of success--the ability to avoid vulnerable states and operate efficiently--thus depends on the skill in projecting future states and the ability to select the most efficient strategies to address vulnerabilities. This research develops a robust decision making framework that incorporates new methods of decadal scale projections with selection of efficient strategies. Previous approaches to water resources planning under inter-annual climate variability combining skillful seasonal flow forecasts with climatology for subsequent years are not skillful for medium term (i.e. decadal scale) projections as decision makers are not able to plan adequately to avoid vulnerabilities. We address this need by integrating skillful decadal scale streamflow projections into the robust decision making framework and making the probability distribution of this projection available to the decision making logic. The range of possible future hydrologic scenarios can be defined using a variety of nonparametric methods. Once defined, an ensemble projection of decadal flow scenarios are generated from a wavelet-based spectral K-nearest-neighbor resampling approach using historical and paleo-reconstructed data. This method has been shown to generate skillful medium term projections with a rich variety of natural variability. The current state of the system in combination with the probability distribution of the projected flow ensembles enables the selection of appropriate decision options. This process is repeated for each year of the planning horizon--resulting in system outcomes that can be evaluated on their performance and resiliency. The research utilizes the RiverSMART suite of software modeling and analysis tools developed under the Bureau of Reclamation's WaterSMART initiative and built around the RiverWare modeling environment. A case study is developed for the Gunnison and Upper Colorado River Basins. The ability to mitigate vulnerability using the framework is gauged by system performance indicators that measure the ability of the system to meet various water demands (i.e. agriculture, environmental flows, hydropower etc.). Options and strategies for addressing vulnerabilities include measures such as conservation, reallocation and adjustments to operational policy. In addition to being able to mitigate vulnerabilities, options and strategies are evaluated based on benefits, costs and reliability. Flow ensembles are also simulated to incorporate mean and variance from climate change projections for the planning horizon and the above robust decision-making framework is applied to evaluate its performance under changing climate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H21H..08H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H21H..08H"><span>Hourly Water Quality Dynamics in Rivers Downstream of Urban Areas: Quantifying Seasonal Variation and Modelling Impacts of Urban Growth</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hutchins, M.; McGrane, S. J.; Miller, J. D.; Hitt, O.; Bowes, M.</p> <p>2016-12-01</p> <p>Continuous monitoring of water flows and quality is invaluable in improving understanding of the influence of urban areas on river health. When used to inform predictive modelling, insights can be gained as to how urban growth may affect the chemical and biological quality of rivers as they flow downstream into larger waterbodies. Water flow and quality monitoring in two urbanising sub-catchments (<100 km2) of the River Thames (southern UK) is described. Temperature, conductivity, turbidity, dissolved oxygen (DO) and ammonium (NH4) were measured at downstream locations where long term flow records are available, but particular focus is given to monitoring of an extended set of sites during prolonged winter rainfall. In the Ray sub-catchment streams were monitored in which urban cover varied across a range of 7-78%. A rural-urban gradient in DO was apparent in the low flow period prior to the storms. Transient low DO (< 8 mg L-1) as a response to pollutant first flushes was particularly apparent in urban streams but this was followed by a rapid recovery. Chronic effects lasting for three to four weeks were only seen downstream of a sewage treatment works (STW). In this respect temperature- and respiration-driven DO sags in summer were at least if not more severe than those driven by the winter storms. Likewise, although winter storm NH4 concentrations violated EU legislation downstream of the STW, they were lower than summer concentrations in pollutant flushes following dry spells. In contrast the predominant phenomenon affecting water quality in the Cut during the storms was dilution. Here, a river water quality model was calibrated and applied over the course of a year to capture the importance of periphyton photosynthesis and respiration cycles in determining water quality and to predict the influence of hypothetical urban growth on downstream river health. The periods monitored intensively, dry spells followed by prolonged rainfall, represent: (i) marked changes in conditions likely to become more prevalent in future, (ii) situations under which water quality in urban areas is likely to be particularly vulnerable, being influenced for example by first flush effects followed by capacity exceedance at STW. Despite this, whilst being somewhat long lasting in places, impacts on DO were not severe.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15503385','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15503385"><span>Effect of human activities on overall trend of sedimentation in the lower Yellow River, China.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jiongxin, Xu</p> <p>2004-05-01</p> <p>The Yellow River has been intensively affected by human activities, particularly in the past 50 years, including soil-water conservation in the upper and middle drainage basin, flood protection in the lower reaches, and flow regulation and water diversion in the whole drainage basin. All these changes may impact sedimentation process of the lower Yellow River in different ways. Assessing these impacts comprehensively is important for more effective environmental management of the drainage basin. Based on the data of annual river flow, sediment load, and channel sedimentation in the lower Yellow River between 1950 and 1997, the purpose of this paper is to analyze the overall trend of channel sedimentation rate at a time scale of 50 years, and its formative cause. It was found in this study that erosion control measures and water diversion have counteractive impacts on sedimentation rate in the lower Yellow River. Although both annual river flow and sediment decreased, there was no change in channel sedimentation rate. A regression analysis indicated that the sedimentation in the lower Yellow River decreased with the sediment input to the lower Yellow River but increased with the river flow input. In the past 30-40 years, the basin-wide practice of erosion and sediment control measures resulted in a decline in sediment supply to the Yellow River; at the same time, the human development of water resources that required river flow regulation and water diversion caused great reduction in river flow. The former may reduce the sedimentation in the lower Yellow River, but the reduction of river flow increased the sedimentation. When their effects counterbalanced each other, the overall trend of channel sedimentation in the lower Yellow River remained unchanged. This fact may help us to better understand the positive and negative effects of human activities in the Yellow River basin and to pay more attention to the negative effect of the development of water resources. The results of this study demonstrate that, if the overuse of river water cannot be controlled, the reduction of channel sedimentation in the lower Yellow River cannot be realized through the practice of erosion and sediment control measures.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.sciencedirect.com/science/article/pii/S0048969713006530','USGSPUBS'); return false;" href="http://www.sciencedirect.com/science/article/pii/S0048969713006530"><span>River flow changes related to land and water management practices across the conterminous United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Eng, Ken; Wolock, David M.; Carlisle, Daren M.</p> <p>2013-01-01</p> <p>The effects of land and water management practices (LWMP)—such as the construction of dams and roads—on river flows typically have been studied at the scale of single river watersheds or for a single type of LWMP. For the most part, assessments of the relative effects of multiple LWMP within many river watersheds across regional and national scales have been lacking. This study assesses flow alteration—quantified as deviation of several flow metrics from natural conditions—at 4196 gauged rivers affected by a variety of LWMP across the conterminous United States. The most widespread causes of flow changes among the LWMP considered were road density and dams. Agricultural development and wastewater discharges also were associated with flow changes in some regions. Dams generally reduced most attributes of flow, whereas road density, agriculture and wastewater discharges tended to be associated with increased flows compared to their natural condition.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21517832','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21517832"><span>An analysis of river bank slope and unsaturated flow effects on bank storage.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Doble, Rebecca; Brunner, Philip; McCallum, James; Cook, Peter G</p> <p>2012-01-01</p> <p>Recognizing the underlying mechanisms of bank storage and return flow is important for understanding streamflow hydrographs. Analytical models have been widely used to estimate the impacts of bank storage, but are often based on assumptions of conditions that are rarely found in the field, such as vertical river banks and saturated flow. Numerical simulations of bank storage and return flow in river-aquifer cross sections with vertical and sloping banks were undertaken using a fully-coupled, surface-subsurface flow model. Sloping river banks were found to increase the bank infiltration rates by 98% and storage volume by 40% for a bank slope of 3.4° from horizontal, and for a slope of 8.5°, delay bank return flow by more than four times compared with vertical river banks and saturated flow. The results suggested that conventional analytical approximations cannot adequately be used to quantify bank storage when bank slope is less than 60° from horizontal. Additionally, in the unconfined aquifers modeled, the analytical solutions did not accurately model bank storage and return flow even in rivers with vertical banks due to a violation of the dupuit assumption. Bank storage and return flow were also modeled for more realistic cross sections and river hydrograph from the Fitzroy River, Western Australia, to indicate the importance of accurately modeling sloping river banks at a field scale. Following a single wet season flood event of 12 m, results showed that it may take over 3.5 years for 50% of the bank storage volume to return to the river. © 2011, The Author(s). Ground Water © 2011, National Ground Water Association.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/52175','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/52175"><span>Economic value of instream flow in Montana's Big Hole and Bitterroot Rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>John W. Duffield; Thomas C Brown; Stewart D. Allen</p> <p>1994-01-01</p> <p>Instream flow is valuable to recreationists who rely on flows for fishing, boating, and other forms of river recreation. Instream flow is also valuable to many members of society, whether they visit the rivers or not, because flows maintain ecosystem stability and associated fish and wildlife habitat. This study estimates the economic value of these recreation...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2012/1240/pdf/ofr20121240.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2012/1240/pdf/ofr20121240.pdf"><span>Geomorphic and hydrologic study of peak-flow management on the Cedar River, Washington</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Magirl, Christopher S.; Gendaszek, Andrew S.; Czuba, Christiana R.; Konrad, Christopher P.; Marineau, Mathieu D.</p> <p>2012-01-01</p> <p>Assessing the linkages between high-flow events, geomorphic response, and effects on stream ecology is critical to river management. High flows on the gravel-bedded Cedar River in Washington are important to the geomorphic function of the river; however, high flows can deleteriously affect salmon embryos incubating in streambed gravels. A geomorphic analysis of the Cedar River showed evidence of historical changes in river form over time and quantified the effects of anthropogenic alterations to the river corridor. Field measurements with accelerometer scour monitors buried in the streambed provided insight into the depth and timing of streambed scour during high-flow events. Combined with a two-dimensional hydrodynamic model, the recorded accelerometer disturbances allowed the prediction of streambed disturbance at the burial depth of Chinook and sockeye salmon egg pockets for different peak discharges. Insight gained from these analyses led to the development of suggested monitoring metrics for an ongoing geomorphic monitoring program on the Cedar River.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GPC...160...61Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GPC...160...61Z"><span>Evaluation of ecological instream flow considering hydrological alterations in the Yellow River basin, China</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Qiang; Zhang, Zongjiao; Shi, Peijun; Singh, Vijay P.; Gu, Xihui</p> <p>2018-01-01</p> <p>The Yellow River is the second largest river in China and is the important source for water supply in the northwestern and northern China. It is often regarded as the mother river of China. Owing to climatic change and intensifying human activities, such as increasing withdrawal of water for meeting growing agricultural irrigation needs since 1986, the flow of Yellow River has decreased, with serious impacts on the ecological environment. Using multiple hydrological indicators and Flow Duration Curve (DFC)-based ecodeficit and ecosurplus, this study investigates the impact of hydrological alterations, such as the impact of water reservoirs or dams, on downstream ecological instream flow. Results indicate that: (1) due to the impoundment and hydrological regulations of water reservoirs, occurrence rates and magnitudes of high flow regimes have decreased and the decrease is also found in the magnitudes of low flow events. These changes tend to be more evident from the upper to the lower Yellow River basin; (2) human activities tend to enhance the instream flow variability, particularly after the 1980s;(3) the ecological environment in different parts of the Yellow River basin is under different degrees of ecological risk. In general, lower to higher ecological risk can be detected due to hydrological alterations from the upper to the lower Yellow River basin. This shows that conservation of ecological environment and river health is facing a serious challenge in the lower Yellow River basin; (4) ecological instream flow indices, such as ecodeficit and ecosurplus, and IHA32 hydrological indicators are in strong relationships, suggesting that ecodeficit and ecosurplus can be regarded as appropriate ecological indicators for developing measures for mitigating the adverse impact of human activities on the conservation of ecological environment in the Yellow River basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUSM.U22A..09H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUSM.U22A..09H"><span>Baseline for Monitoring Water Resources Along Kabul and Indus Rivers of Pakistan for Potential Terrorist Contamination</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hamidullah, S.; Tariq, S.; Shah, M. T.; Bishop, M. P.; Kamp, U.; Olsenholler, J.</p> <p>2002-05-01</p> <p>Baseline for Monitoring Water Resources Along Kabul and Indus Rivers of Pakistan for Potential Terrorist Contamination Terrorism has temporarily constrained the dynamism of the world it was enjoying before September 11, 2001, but also has opened avenues for people of all ethnicities, creeds, and professions to join hands in combating it. Scientific efforts to combat terrorism are likely to lead to better use of existing scientific knowledge as well as to discoveries that will increase world organization, interconnectivity, and peace promotion. Afghanistan and surrounding regions are major focal points for current anti-terrorist activities of the USA and its allies, including Pakistan. The United States, Pakistan, and Afghanistan have shared many similar political objectives, as well as differences, in cold war and post-cold-war eras, reflected by variable provisions of material aid. It is well recognized that understanding Afghanistan requires comprehension of the Pakistan situation as well, especially for common resources. Water is paramount because it is absolutely vital, but can be contaminated by internal or cross-border terrorism. The Kabul and Indus rivers originate in the Hindu Kush - Himalaya ranges. The Kabul River flows from Afghanistan into Pakistan, and after irrigating Peshawar basin, joins the Indus. The Indus, after its origin in Tibet and flow through the Indian Himalaya, enters Pakistan and flows south as the irrigation lifeblood of the country. Any terroristic addition of radioactive nuclides or contaminants to either river could dramatically impact the dependent riverine ecologies. Monitoring cells thus need to be established at locations in Afghanistan and Pakistan to assess base-line river variances for possible future contamination by terrorists. This paper presents a general view and the physical and chemical parameters of parts of the two rivers, and of the surrounding underground water in Peshawar Basin, including pH, conductivity, total dissolved solids, major elements, trace elements, heavy metals and oxygen isotopes. Data are mostly within allowed limits of US-EPA for surface and underground water. Oxygen isotopes confirm the dangers of contamination from the Kabul River to underground water. Heavy metals were determined through spectrophotometery, however, modern geophysical methods are cheaper and quicker and can be applied at monitoring stations. With Kabul river and its surroundings as examples, similar theory and practice can be applied to rivers within the United States and other parts of the world.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.9522L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.9522L"><span>Run-of-river power plants in Alpine regions: whither optimal capacity?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lazzaro, Gianluca; Botter, Gianluca</p> <p>2015-04-01</p> <p>Hydropower is the major renewable electricity generation technology worldwide. The future expansion of this technology mostly relies on the development of small run-of-river projects, in which a fraction of the running flows is diverted from the river to a turbine for energy production. Even though small hydro inflicts a smaller impact on aquatic ecosystems and local communities compared to large dams, it cannot prevent stresses on plant, animal, and human well-being. This is especially true in mountain regions where the plant outflow is located several kilometers downstream of the intake, thereby inducing the depletion of river reaches of considerable length. Moreover, the negative cumulative effects of run-of-river systems operating along the same river threaten the ability of stream networks to supply ecological corridors for plants, invertebrates or fishes, and support biodiversity. Research in this area is severely lacking. Therefore, the prediction of the long-term impacts associated to the expansion of run-of-river projects induced by global-scale incentive policies remains highly uncertain. This contribution aims at providing objective tools to address the preliminary choice of the capacity of a run-of-river hydropower plant when the economic value of the plant and the alteration of the flow regime are simultaneously accounted for. This is done using the concepts of Pareto-optimality and Pareto-dominance, which are powerful tools suited to face multi-objective optimization in presence of conflicting goals, such as the maximization of the profitability and the minimization of the hydrologic disturbance induced by the plant in the river reach between the intake and the outflow. The application to a set of case studies belonging to the Piave River basin (Italy) suggests that optimal solutions are strongly dependent the natural flow regime at the plant intake. While in some cases (namely, reduced streamflow variability) the optimal trade-off between economic profitability and hydrologic disturbance is well identified, in other cases (enhanced streamflow variability) multiple options and/or ranges of optimal capacities may be devised. Such alternatives offer to water managers an objective basis to identify optimal allocation of resources and policy actions. Small hydro technology is likely to gain a higher social value in the next decades if the environmental and hydrologic footprint associated to the energetic exploitation of surface water will take a higher priority in civil infrastructures planning.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013WRR....49.4346C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013WRR....49.4346C"><span>Statistical modeling of daily and subdaily stream temperatures: Application to the Methow River Basin, Washington</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caldwell, R. J.; Gangopadhyay, S.; Bountry, J.; Lai, Y.; Elsner, M. M.</p> <p>2013-07-01</p> <p>Management of water temperatures in the Columbia River Basin (Washington) is critical because water projects have substantially altered the habitat of Endangered Species Act listed species, such as salmon, throughout the basin. This is most important in tributaries to the Columbia, such as the Methow River, where the spawning and rearing life stages of these cold water fishes occurs. Climate change projections generally predict increasing air temperatures across the western United States, with less confidence regarding shifts in precipitation. As air temperatures rise, we anticipate a corresponding increase in water temperatures, which may alter the timing and availability of habitat for fish reproduction and growth. To assess the impact of future climate change in the Methow River, we couple historical climate and future climate projections with a statistical modeling framework to predict daily mean stream temperatures. A K-nearest neighbor algorithm is also employed to: (i) adjust the climate projections for biases compared to the observed record and (ii) provide a reference for performing spatiotemporal disaggregation in future hydraulic modeling of stream habitat. The statistical models indicate the primary drivers of stream temperature are maximum and minimum air temperature and stream flow and show reasonable skill in predictability. When compared to the historical reference time period of 1916-2006, we conclude that increases in stream temperature are expected to occur at each subsequent time horizon representative of the year 2020, 2040, and 2080, with an increase of 0.8 ± 1.9°C by the year 2080.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70191053','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70191053"><span>Projecting impacts of climate change on water availability using artificial neural network techniques</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Swain, Eric D.; Gomez-Fragoso, Julieta; Torres-Gonzalez, Sigfredo</p> <p>2017-01-01</p> <p>Lago Loíza reservoir in east-central Puerto Rico is one of the primary sources of public water supply for the San Juan metropolitan area. To evaluate and predict the Lago Loíza water budget, an artificial neural network (ANN) technique is trained to predict river inflows. A method is developed to combine ANN-predicted daily flows with ANN-predicted 30-day cumulative flows to improve flow estimates. The ANN application trains well for representing 2007–2012 and the drier 1994–1997 periods. Rainfall data downscaled from global circulation model (GCM) simulations are used to predict 2050–2055 conditions. Evapotranspiration is estimated with the Hargreaves equation using minimum and maximum air temperatures from the downscaled GCM data. These simulated 2050–2055 river flows are input to a water budget formulation for the Lago Loíza reservoir for comparison with 2007–2012. The ANN scenarios require far less computational effort than a numerical model application, yet produce results with sufficient accuracy to evaluate and compare hydrologic scenarios. This hydrologic tool will be useful for future evaluations of the Lago Loíza reservoir and water supply to the San Juan metropolitan area.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2009/5011/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2009/5011/"><span>Trends in Streamflow Characteristics of Selected Sites in the Elkhorn River, Salt Creek, and Lower Platte River Basins, Eastern Nebraska, 1928-2004, and Evaluation of Streamflows in Relation to Instream-Flow Criteria, 1953-2004</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dietsch, Benjamin J.; Godberson, Julie A.; Steele, Gregory V.</p> <p>2009-01-01</p> <p>The Nebraska Department of Natural Resources approved instream-flow appropriations on the Platte River to maintain fish communities, whooping crane roost habitat, and wet meadows used by several wild bird species. In the lower Platte River region, the Nebraska Game and Parks Commission owns an appropriation filed to maintain streamflow for fish communities between the Platte River confluence with the Elkhorn River and the mouth of the Platte River. Because Elkhorn River flow is an integral part of the flow in the reach addressed by this appropriation, the Upper Elkhorn and Lower Elkhorn Natural Resources Districts are involved in overall management of anthropogenic effects on the availability of surface water for instream requirements. The Physical Habitat Simulation System (PHABSIM) and other estimation methodologies were used previously to determine instream requirements for Platte River biota, which led to the filing of five water appropriations applications with the Nebraska Department of Natural Resources in 1993 by the Nebraska Game and Parks Commission. One of these requested instream-flow appropriations of 3,700 cubic feet per second was for the reach from the Elkhorn River to the mouth of the Platte River. Four appropriations were granted with modifications in 1998, by the Nebraska Department of Natural Resources. Daily streamflow data for the periods of record were summarized for 17 streamflow-gaging stations in Nebraska to evaluate streamflow characteristics, including low-flow intervals for consecutive durations of 1, 3, 7, 14, 30, 60, and 183 days. Temporal trends in selected streamflow statistics were not adjusted for variability in precipitation. Results indicated significant positive temporal trends in annual flow for the period of record at eight streamflow-gaging stations - Platte River near Duncan (06774000), Platte River at North Bend (06796000), Elkhorn River at Neligh (06798500), Logan Creek near Uehling (06799500), Maple Creek near Nickerson (06800000), Elkhorn River at Waterloo (06800500), Salt Creek at Greenwood (06803555), and Platte River at Louisville (06805500). In general, sites in the Elkhorn River Basin upstream from Norfolk showed fewer significant trends than did sites downstream from Norfolk and sites in the Platte River and Salt Creek basins, where trends in low flows also were positive. Historical Platte River streamflow records for the streamflow-gaging station at Louisville, Nebraska, were used to determine the number of days per water year (Sept. 30 to Oct. 1) when flows failed to satisfy the minimum criteria of the instream-flow appropriation prior to its filing in 1993. Before 1993, the median number of days the criteria were not satisfied was about 120 days per water year. During 1993 through 2004, daily mean flows at Louisville, Nebraska, have failed to satisfy the criteria for 638 days total (median value equals 21.5 days per year). Most of these low-flow intervals occurred in summer through early fall. For water years 1953 through 2004, of the discrete intervals when flow was less that the criteria levels, 61 percent were 3 days or greater in duration, and 38 percent were 7 days or greater in duration. The median duration of intervals of flow less than the criteria levels was 4 consecutive days during 1953 through 2004.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70018022','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70018022"><span>Debris flows in Grand Canyon National Park, Arizona: magnitude, frequency and effects on the Colorado River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Melis, Theodre S.; Webb, Robert H.; ,</p> <p>1993-01-01</p> <p>Debris flows are recurrent sediment-transport processes in 525 tributaries of the Colorado River in Grand Canyon. Arizona. Initiated by slope failures in bedrock and (or) colluvium during intense rainfall, Grand Canyon debris flows are high-magnitude, short-duration floods. Debris flows in these tributaries transport very large boulders into the river where they accumulate on debris fans and form rapids. The frequency of debris flows range from less than 1 per century to 10 or more per century in these tributaries. Before regulation by Glen Canyon Dam in 1963, high-magnitude floods on the Colorado River reworked debris fans by eroding all particles except large boulders. Because flow regulation has substantially decreased the river's competence, debris flows occurring after 1963 have increased accumulation of finer-grained sediments on debris fans and in rapids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/1078167-application-eloha-framework-regulated-rivers-upper-tennessee-river-basin-case-study','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1078167-application-eloha-framework-regulated-rivers-upper-tennessee-river-basin-case-study"><span>Application of the ELOHA Framework to Regulated Rivers in the Upper Tennessee River Basin: A Case Study</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>McManamay, Ryan A; Orth, Dr. Donald J; Dolloff, Dr. Charles A</p> <p>2013-01-01</p> <p>In order for habitat restoration in regulated rivers to be effective at large scales, broadly applicable frameworks are needed that provide measurable objectives and contexts for management. The Ecological Limits of Hydrologic Alteration (ELOHA) framework was created as a template to assess hydrologic alterations, develop relationships between altered streamflow and ecology, and establish environmental flow standards. We tested the utility of ELOHA in informing flow restoration applications for fish and riparian communities in regulated rivers in the Upper Tennessee River Basin (UTRB). We followed the steps of ELOHA to generate flow alteration-ecological response relationships and then determined whether those relationshipsmore » could predict fish and riparian responses to flow restoration in the Cheoah River, a regulated system within the UTRB. Although ELOHA provided a robust template to construct hydrologic information and predict hydrology for ungaged locations, our results do not support the assertion that over-generalized univariate relationships between flow and ecology can produce results sufficient to guide management in regulated rivers. After constructing multivariate models, we successfully developed predictive relationships between flow alterations and fish/riparian responses. In accordance with model predictions, riparian encroachment displayed consistent decreases with increases in flow magnitude in the Cheoah River; however, fish richness did not increase as predicted four years post- restoration. Our results suggest that altered temperature and substrate and the current disturbance regime may have reduced opportunities for fish species colonization. Our case study highlights the need for interdisciplinary science in defining environmental flows for regulated rivers and the need for adaptive management approaches once flows are restored.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016WRR....52.8159S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016WRR....52.8159S"><span>Flow reconstructions in the Upper Missouri River Basin using riparian tree rings</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schook, Derek M.; Friedman, Jonathan M.; Rathburn, Sara L.</p> <p>2016-10-01</p> <p>River flow reconstructions are typically developed using tree rings from montane conifers that cannot reflect flow regulation or hydrologic inputs from the lower portions of a watershed. Incorporating lowland riparian trees may improve the accuracy of flow reconstructions when these trees are physically linked to the alluvial water table. We used riparian plains cottonwoods (Populus deltoides ssp. monilifera) to reconstruct discharge for three neighboring rivers in the Upper Missouri River Basin: the Yellowstone (n = 389 tree cores), Powder (n = 408), and Little Missouri Rivers (n = 643). We used the Regional Curve Standardization approach to reconstruct log-transformed discharge over the 4 months in early summer that most highly correlated to tree ring growth. The reconstructions explained at least 57% of the variance in historical discharge and extended back to 1742, 1729, and 1643. These are the first flow reconstructions for the Lower Yellowstone and Powder Rivers, and they are the furthest downstream among Rocky Mountain rivers in the Missouri River Basin. Although mostly free-flowing, the Yellowstone and Powder Rivers experienced a shift from early-summer to late-summer flows within the last century. This shift is concurrent with increasing irrigation and reservoir storage, and it corresponds to decreased cottonwood growth. Low-frequency flow patterns revealed wet conditions from 1870 to 1980, a period that includes the majority of the historical record. The 1816-1823 and 1861-1865 droughts were more severe than any recorded, revealing that drought risks are underestimated when using the instrumental record alone.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2013/5134/pdf/sir2013-5134.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2013/5134/pdf/sir2013-5134.pdf"><span>Potential depletion of surface water in the Colorado River and agricultural drains by groundwater pumping in the Parker-Palo Verde-Cibola area, Arizona and California</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Leake, Stanley A.; Owen-Joyce, Sandra J.; Heilman, Julian A.</p> <p>2013-01-01</p> <p>Water use along the lower Colorado River is allocated as “consumptive use,” which is defined to be the amount of water diverted from the river minus the amount that returns to the river. Diversions of water from the river include surface water in canals and water removed from the river by pumping wells in the aquifer connected to the river. A complication in accounting for water pumped by wells occurs if the pumping depletes water in drains and reduces measured return flow in those drains. In that case, consumptive use of water pumped by the wells is accounted for in the reduction of measured return flow. A method is needed to understand where groundwater pumping will deplete water in the river and where it will deplete water in drains. To provide a basis for future accounting for pumped groundwater in the Parker-Palo Verde-Cibola area, a superposition model was constructed. The model consists of three layers of finite-difference cells that cover most of the aquifer in the study area. The model was run repeatedly with each run having a pumping well in a different model cell. The source of pumped water that is depletion of the river, expressed as a fraction of the pumping rate, was computed for all active cells in model layer 1, and maps were constructed to understand where groundwater pumping depletes the river and where it depletes drains. The model results indicate that if one or more drains exist between a pumping well location and the river, nearly all of the depletion will be from drains, and little or no depletion will come from the Colorado River. Results also show that if a well pumps on a side of the river with no drains in the immediate area, depletion will come from the Colorado River. Finally, if a well pumps between the river and drains that parallel the river, a fraction of the pumping will come from the river and the rest will come from the drains. Model results presented in this report may be considered in development or refinement of strategies for accounting for groundwater pumping in the river aquifer connected to the Colorado River in the study area.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JHyd..551..470Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JHyd..551..470Z"><span>Coupling habitat suitability and ecosystem health with AEHRA to estimate E-flows under intensive human activities</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, C. S.; Yang, S. T.; Zhang, H. T.; Liu, C. M.; Sun, Y.; Yang, Z. Y.; Zhang, Y.; Dong, B. E.; Lim, R. P.</p> <p>2017-08-01</p> <p>Sustaining adequate environmental flows (e-flows) is a key principle for maintaining river biodiversity and ecosystem health, and for supporting sustainable water resource management in basins under intensive human activities. But few methods could correctly relate river health to e-flows assessment at the catchment scale when they are applied to rivers highly impacted by human activities. An effective method is presented in this study to closely link river health to e-flows assessment for rivers at the catchment scale. Key fish species, as indicators of ecosystem health, were selected by using the foodweb model. A multi-species-based habitat suitability model (MHSI) was improved, and coupled with dominance of the key fish species as well as the Index of Biological Integrity (IBI) to enhance its accuracy in determining the fish-preferred key hydrologic habitat variables related to ecosystem health. Taking 5964 fish samples and concurrent hydrological habitat variables as the basis, the combination of key variables of flow-velocity and water-depth were determined and used to drive the Adapted Ecological Hydraulic Radius Approach (AEHRA) to study e-flows in a Chinese urban river impacted by intensive human activities. Results showed that upstream urbanization resulted in abnormal river-course geomorphology and consequently abnormal e-flows under intensive human activities. Selection of key species based on the foodweb and trophic levels of aquatic ecosystems can reflect a comprehensive requirement on e-flows of the whole aquatic ecosystem, which greatly increases its potential to be used as a guidance tool for rehabilitation of degraded ecosystems at large spatial scales. These findings have significant ramifications for catchment e-flows assessment under intensive human activities and for river ecohealth restoration in such rivers globally.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1913634K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1913634K"><span>Comparison and Validation of Hydrological E-Flow Methods through Hydrodynamic Modelling</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuriqi, Alban; Rivaes, Rui; Sordo-Ward, Alvaro; Pinheiro, António N.; Garrote, Luis</p> <p>2017-04-01</p> <p>Flow regime determines physical habitat conditions and local biotic configuration. The development of environmental flow guidelines to support the river integrity is becoming a major concern in water resources management. In this study, we analysed two sites located in southern part of Portugal, respectively at Odelouca and Ocreza Rivers, characterised by the Mediterranean climate. Both rivers are almost in pristine condition, not regulated by dams or other diversion construction. This study presents an analysis of the effect on fish habitat suitability by the implementation of different hydrological e-flow methods. To conduct this study we employed certain hydrological e-flow methods recommended by the European Small Hydropower Association (ESHA). River hydrology assessment was based on approximately 30 years of mean daily flow data, provided by the Portuguese Water Information System (SNIRH). The biological data, bathymetry, physical and hydraulic features, and the Habitat Suitability Index for fish species were collected from extensive field works. We followed the Instream Flow Incremental Methodology (IFIM) to assess the flow-habitat relationship taking into account the habitat suitability of different instream flow releases. Initially, we analysed fish habitat suitability based on natural conditions, and we used it as reference condition for other scenarios considering the chosen hydrological e-flow methods. We accomplished the habitat modelling through hydrodynamic analysis by using River-2D model. The same methodology was applied to each scenario by considering as input the e-flows obtained from each of the hydrological method employed in this study. This contribution shows the significance of ecohydrological studies in establishing a foundation for water resources management actions. Keywords: ecohydrology, e-flow, Mediterranean rivers, river conservation, fish habitat, River-2D, Hydropower.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4514816','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4514816"><span>Evaluation of Spatial Pattern of Altered Flow Regimes on a River Network Using a Distributed Hydrological Model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ryo, Masahiro; Iwasaki, Yuichi; Yoshimura, Chihiro; Saavedra V., Oliver C.</p> <p>2015-01-01</p> <p>Alteration of the spatial variability of natural flow regimes has been less studied than that of the temporal variability, despite its ecological importance for river ecosystems. Here, we aimed to quantify the spatial patterns of flow regime alterations along a river network in the Sagami River, Japan, by estimating river discharge under natural and altered flow conditions. We used a distributed hydrological model, which simulates hydrological processes spatiotemporally, to estimate 20-year daily river discharge along the river network. Then, 33 hydrologic indices (i.e., Indicators of Hydrologic Alteration) were calculated from the simulated discharge to estimate the spatial patterns of their alterations. Some hydrologic indices were relatively well estimated such as the magnitude and timing of maximum flows, monthly median flows, and the frequency of low and high flow pulses. The accuracy was evaluated with correlation analysis (r > 0.4) and the Kolmogorov–Smirnov test (α = 0.05) by comparing these indices calculated from both observed and simulated discharge. The spatial patterns of the flow regime alterations varied depending on the hydrologic indices. For example, both the median flow in August and the frequency of high flow pulses were reduced by the maximum of approximately 70%, but these strongest alterations were detected at different locations (i.e., on the mainstream and the tributary, respectively). These results are likely caused by different operational purposes of multiple water control facilities. The results imply that the evaluation only at discharge gauges is insufficient to capture the alteration of the flow regime. Our findings clearly emphasize the importance of evaluating the spatial pattern of flow regime alteration on a river network where its discharge is affected by multiple water control facilities. PMID:26207997</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AcGeo.tmp....8P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AcGeo.tmp....8P"><span>Trend detection in river flow indices in Poland</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piniewski, Mikołaj; Marcinkowski, Paweł; Kundzewicz, Zbigniew W.</p> <p>2018-02-01</p> <p>The issue of trend detection in long time series of river flow records is of vast theoretical interest and considerable practical relevance. Water management is based on the assumption of stationarity; hence, it is crucial to check whether taking this assumption is justified. The objective of this study is to analyse long-term trends in selected river flow indices in small- and medium-sized catchments with relatively unmodified flow regime (semi-natural catchments) in Poland. The examined indices describe annual and seasonal average conditions as well as annual extreme conditions—low and high flows. The special focus is on the spatial analysis of trends, carried out on a comprehensive, representative data set of flow gauges. The present paper is timely, as no spatially comprehensive studies (i.e. covering the entire Poland or its large parts) on trend detection in time series of river flow have been done in the recent 15 years or so. The results suggest that there is a strong random component in the river flow process, the changes are weak and the spatial pattern is complex. Yet, the results of trend detection in different indices of river flow in Poland show that there exists a spatial divide that seems to hold quite generally for various indices (annual, seasonal, as well as low and high flow). Decreases of river flow dominate in the northern part of the country and increases usually in the southern part. Stations in the central part show mostly `no trend' results. However, the spatial gradient is apparent only for the data for the period 1981-2016 rather than for 1956-2016. It seems also that the magnitude of increases of river flow is generally lower than that of decreases.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1915480M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1915480M"><span>Hydromorphological assessment and catchment characterisation in the headwaters of the Volga River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marquez, Fabian; Kuzovlev, Vyacheslav. V.; Schletterer, Martin</p> <p>2017-04-01</p> <p>Keywords: hydromorphological assessment, lowland river, reference conditions. The Volga River and its watershed represent the largest river system in Europe. The river is considered as the Russian lifeline, and various anthropogenic activities influenced the river. Nevertheless, its headwaters remained in least disturbed conditions. We present an assessment as well as an evaluation of hydromorphological conditions in the headwaters of the Volga River regarding (1) channel, (2) banks/riparian zone and (3) floodplain. The assessment follows European standards (CEN 2004) and also includes the Habitat Quality Survey (HQA). Historical flows from five gauging stations along the studied reach were analysed to determine the hydrological characteristics. The highest flows are observed during March and April, followed by summer low flows, higher flows during October and November and low flows again during winter. A decreasing tendency of the mean annual discharge is noted throughout the observation time as it accentuates in the downstream direction when comparing the stations. Based on the specific discharge (volume of water per unit time per unit area) from these gauging stations , a flow reconstruction for the Tudovka River was carried out. These analyses contribute to the REFCOND_VOLGA project, a long-term ecological monitoring programme in the headwaters of the Volga River. The research area is characterised by large forests and low population densities, thus the results provide data about reference or least impacted sites. Due to the hydromorphological characteristics the headwaters of the Volga River, i.e. the free-flowing section between the Upper Volga Lakes and Tver represents an intact lowland river and comprises a refugial system for potamalic flora and fauna.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=63715&keyword=high+AND+flow+AND+oxygen&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=63715&keyword=high+AND+flow+AND+oxygen&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>WATER QUALITY EFFECTS OF HYPORHEIC PROCESSING IN A LARGE RIVER</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Water quality changes along hyporheic flow paths may have<br>important effects on river water quality and aquatic habitat. Previous<br>studies on the Willamette River, Oregon, showed that river water follows<br>hyporheic flow paths through highly porous deposits created by river...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Geomo.298...31H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Geomo.298...31H"><span>Combined effects of multiple large-scale hydraulic engineering on water stages in the middle Yangtze River</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Han, Jianqiao; Sun, Zhaohua; Li, Yitian; Yang, Yunping</p> <p>2017-12-01</p> <p>Investigation of water stages influenced by human projects provides better understanding of riverine geomorphological processes and river management. Based on hydrological data collected over 60 years, an extreme stage-extreme discharge analysis and a specific-gauge analysis were performed to research the individual and combined effects of multiple engineering projects on a long-term time series of water stages in the middle Yangtze River. Conclusions are as follows. (1) In accordance with the operation years of the Jingjiang cutoff (CF), the Gezhouba Dam (GD), and the Three Gorges Dam (TGD), the time series (1955-2012) was divided into periods of P1 (1955-1970), P2 (1971-1980), P3 (1981-2002), and P4 (2003 - 2012). Water stage changes during P1-P2, P2-P3, and P3-P4 are varied because of the differences in the types and scales of these projects. The stage decreased at Shashi and increased at Luoshan owing to the operation of the CF. Additionally, after the GD was constructed, the low-flow stage decreased in the upstream reach of Chenglingji and increased in its downstream reach, whereas the flood stage merely decreased at Yichang. Moreover, the TGD resulted in an overall decrease in low-flow stages and a limited increase in flood stages because of the differential adjustments of river geometry and resistance between the low-flow channel and flood channel. (2) Although differences existed in the scouring mechanisms between streamwise erosion associated with dams and headward erosion associated with cutoffs, particular bed textures in the gravel reach led to a similar adjustment that stage reduction at Shashi was the greatest of all stations, which caused the flow slope and sediment transport capacity to decrease in the sandy reach. (3) These engineering projects caused changes in average low-flow and flood stages that varied between Yichang (- 1.58 and - 0.08 m respectively), Shashi (- 3.54 and - 0.12 m), and Luoshan (1.15 and 0.97 m) from P1 to P4. However, less influence was observed at Hankou owing to its remote location and the short impoundment time of the TGD. (4) Potentially detrimental decreases in low-flow stages and increases in flood stages should be monitored and managed in the future. Our results are of practical significance for river management and the evaluation of the influences of large-scale anthropogenic activities on the hydrological regimes of large rivers.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70034571','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70034571"><span>Two-dimensional surface river flow patterns measured with paired RiverSondes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Teague, C.C.; Barrick, D.E.; Lilleboe, P.M.; Cheng, R.T.</p> <p>2007-01-01</p> <p>Two RiverSondes were operated simultaneously in close proximity in order to provide a two-dimensional map of river surface velocity. The initial test was carried out at Threemile Slough in central California. The two radars were installed about 135 m apart on the same bank of the channel. Each radar used a 3-yagi antenna array and determined signal directions using direction finding. The slough is approximately 200 m wide, and each radar processed data out to about 300 m, with a range resolution of 15 m and an angular resolution of 1 degree. Overlapping radial vector data from the two radars were combined to produce total current vectors at a grid spacing of 10 m, with updates every 5 minutes. The river flow in the region, which has a maximum velocity of about 0.8 m/s, is tidally driven with flow reversals every 6 hours, and complex flow patterns were seen during flow reversal. The system performed well with minimal mutual interference. The ability to provide continuous, non-contact two-dimensional river surface flow measurements will be useful in several unique settings, such as studies of flow at river junctions where impacts to juvenile fish migration are significant. Additional field experiments are planned this year on the Sacramento River. ?? 2007 IEEE.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70031794','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70031794"><span>Two-dimensional surface river flow patterns measured with paired RiverSondes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Teague, C.C.; Barrick, D.E.; Lilleboe, P.M.; Cheng, R.T.</p> <p>2008-01-01</p> <p>Two RiverSondes were operated simultaneously in close proximity in order to provide a two-dimensional map of river surface velocity. The initial test was carried out at Threemile Slough in central California. The two radars were installed about 135 m apart on the same bank of the channel. Each radar used a 3-yagi antenna array and determined signal directions using direction finding. The slough is approximately 200 m wide, and each radar processed data out to about 300 m, with a range resolution of 15 m and an angular resolution of 1 degree. Overlapping radial vector data from the two radars were combined to produce total current vectors at a grid spacing of 10 m, with updates every 5 minutes. The river flow in the region, which has a maximum velocity of about 0.8 m/s, is tidally driven with flow reversals every 6 hours, and complex flow patterns were seen during flow reversal. The system performed well with minimal mutual interference. The ability to provide continuous, non-contact two-dimensional river surface flow measurements will be useful in several unique settings, such as studies of flow at river junctions where impacts to juvenile fish migration are significant. Additional field experiments are planned this year on the Sacramento River. ?? 2007 IEEE.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC31F..03N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC31F..03N"><span>Hydrologic Responses to Projected Climate Change in Ecologically-Vulnerable Watersheds of the Gulf Coast, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neupane, R. P.; Ficklin, D. L.; Knouft, J.</p> <p>2017-12-01</p> <p>Climate change is likely to have significant effects on the water cycle of the Gulf Coast watersheds in the United States, which contain some of the highest levels of biodiversity of all freshwater systems in North America. Understanding potential hydrologic responses to continued climate change in these watersheds is important for management of water resources and to sustain ecological diversity. We used the Soil and Water Assessment Tool (SWAT) to simulate hydrologic processes and estimate the potential hydrological changes for the mid-21st century (2050s) and the late-21st century (2080s) in the Mobile River, Apalachicola River, and Suwannee River watersheds located in the Gulf Coast, USA. These estimates were based on downscaled future climate projections from 20 Global Circulation Models (GCMs) under two Representative Concentration Pathways (RCPs 4.5 and 8.5). Models were calibrated and validated using observed data from 58, 19, and 14 streamflow gauges in the Mobile River, Apalachicola River, and Suwannee River watersheds, respectively. Evaluation indices including the Nash-Sutcliffe efficiency (NSE), coefficient of determination (R2), and refined index of agreement (dr) were used to assess model quality. The mean values derived during calibration (NSE=0.68, R2=0.77, and dr=0.73) and validation (NSE=0.70, R2=0.78, and dr=0.74) of all watersheds indicated that the models performed well at simulating monthly streamflow. Our simulation results indicated an overall increase in mean annual streamflow for all the watersheds with a maximum increase in discharge of 28.6% for the Suwannee River watershed for RCP 4.5 during the 2080s, which is associated with a 6.8% increase in precipitation during the same time period. We observed an overall warming (4.2oC) with an increase in future precipitation (3.8%) in all watersheds during the 2080s under the worst-case RCP 8.5 scenario compared to the historical time period. Despite an increase in future precipitation, surface runoff in the Suwannee River watershed was lower than might be expected due to a large portion of wetlands ( 28% of total area) acting as buffers to capture overland flows. These outcomes are expected to help in making better-informed decisions for future water resources and ecosystem management in the Gulf Coast region during the coming century.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wsp/1835/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wsp/1835/report.pdf"><span>Chemical quality of surface water in the Allegheny River basin, Pennsylvania and New York</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McCarren, Edward F.</p> <p>1967-01-01</p> <p>The Allegheny River is the principal source of water to many industries and to communities in the upper Ohio River Valley. The river and its many tributaries pass through 19 counties in northwestern and western Pennsylvania. The population in these counties exceeds 3 million. A major user of the Allegheny River is the city of Pittsburgh, which has a population greater than The Allegheny River is as basic to the economy of the upper Ohio River Valley in western Pennsylvania as are the rich deposits of bituminous coal, gas, and oil that underlie the drainage basin. During the past 5 years many streams that flow into the Allegheny have been low flowing because of droughts affecting much of the eastern United States. Consequently, the concentration of solutes in some streams has been unusually high because of wastes from coal mines and oil wells. These and other water-quality problems in the Allegheny River drainage basin are affecting the economic future of some areas in western Pennsylvania. Because of environmental factors such as climate, geology, and land and water uses, surface-water quality varies considerably throughout the river basin. The natural quality of headwater streams, for example, is affected by saltwater wastes from petroleum production. One of the streams most affected is Kinzua Creek, which had 2,900 parts per million chloride in a sample taken at Westline on September 2, 1959. However, after such streams as the Conewango, Brokenstraw, Tionesta, Oil, and French Creeks merge with the Allegheny River, the dissolved-solids and chloride concentrations are reduced by dilution. Central segments of the main river receive water from the Clarion River, Redbank, Mahoning, and Crooked Creeks after they have crossed the coal fields of west-central Pennsylvania. At times, therefore, these streams carry coal-mine wastes that are acidic. The Kiskiminetas River, which crosses these coal fields, discharged sulfuric acid into the Allegheny at a rate of 299 tons a day during the 1962 water year (October 1, 1961, to September 30, 1962). Mine water affects the quality of the Allegheny River most noticeably in its lower part where large withdrawals are made by the Pittsburgh Water Company at Aspinwall and the Wilkinsburg-Penn Joint Water Authority at Nadine. At these places raw river water is chemically .treated in modern treatment plants to control such objectionable characteristics as acidity and excessive concentrations of iron and manganese. Dissolved-solids content in the river varies along its entire length. In its upper reaches the water of the Allegheny River is a sodium chloride type, and at low flow, the sodium chloride is more than half the dissolved solids. In its lower reaches the water is a calcium sulfate .type, and at low flow the calcium sulfate is more than half the dissolved solids. In middle segments of the river from Franklin to Kittanning, water is more dilute and of a mixed type. Many small and several larger streams in the upper basin--such as the Conewango, Brokenstraw, Kinzua, Tionesta, and French Creeks--support large populations of game-fish. Even in segments of the Clarion River, Mahoning, and Redbank Creeks, which are at times affected by coal-mine wastes, fish are present. Although different species withstand varying amounts of contaminants in water, the continued presence of the fish indicates that the water is relatively pure and suitable for recreation and many other uses.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1910074B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1910074B"><span>Assimilation of river altimetry data for effective bed elevation and roughness coefficient</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brêda, João Paulo L. F.; Paiva, Rodrigo C. D.; Bravo, Juan Martin; Passaia, Otávio</p> <p>2017-04-01</p> <p>Hydrodynamic models of large rivers are important prediction tools of river discharge, height and floods. However, these techniques still carry considerable errors; part of them related to parameters uncertainties related to river bathymetry and roughness coefficient. Data from recent spatial altimetry missions offers an opportunity to reduce parameters uncertainty through inverse methods. This study aims to develop and access different methods of altimetry data assimilation to improve river bottom levels and Manning roughness estimations in a 1-D hydrodynamic model. The case study was a 1,100 km reach of the Madeira River, a tributary of the Amazon. The tested assimilation methods are direct insertion, linear interpolation, SCE-UA global optimization algorithm and a Kalman Filter adaptation. The Kalman Filter method is composed by new physically based covariance functions developed from steady-flow and backwater equations. It is accessed the benefits of altimetry missions with different spatio-temporal resolutions, such as ICESAT-1, Envisat and Jason 2. Level time series of 5 gauging stations and 5 GPS river height profiles are used to assess and validate the assimilation methods. Finally, the potential of future missions are discussed, such as ICESAT-2 and SWOT satellites.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1992/4179/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1992/4179/report.pdf"><span>Water availability, use, and estimated future water demand in the upper Duck River basin, middle Tennessee</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hutson, S.S.</p> <p>1993-01-01</p> <p>The Duck River in Tennessee supplied about 18.9 Mgal of water/d to Tullahoma, Manchester, Lewisburg, Columbia, and other cities. Municipal water use increased to 20.9 Mgal/d in 1990; projections indicate increases in demand for the next 25 yr. Socioeconomic and water use data from the basin for 1989 were used to calibrate the water use models within the Institute for Water Resources Municipal and Industrial Needs (IWR-MAIN) System. The models were used to estimate future water use demand in the basin for the years 1995, 2000, and 2015. Projections showed demands of about 24.3 Mgal/d in 1995; 28.3 Mgal/d in 2000; and 39.0 Mgal/d in 2015. Increases in withdrawals from the Duck River downstream from Shelbyville could reduce the minimum flow at Columbia from 119 to 83.8 cu feet/s. The study also included an overview of the potential for developing groundwater resources in the area. Statistical analyses of yields to 5,938 wells showed that the highest yields are in Coffee County, but 75 percent of the wells in Coffee County produced less than 30 gal/m. However, measurements of streamflow losses along tributaries to the Duck River suggest that the potential for development of groundwater does exist at specific sites.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/ds/736/ds736.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/ds/736/ds736.pdf"><span>Land Capability Potential Index (LCPI) and geodatabase for the Lower Missouri River Valley</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chojnacki, Kimberly A.; Struckhoff, Matthew A.; Jacobson, Robert B.</p> <p>2012-01-01</p> <p>The Land Capacity Potential Index (LCPI) is a coarse-scale index intended to delineate broad land-capability classes in the Lower Missouri River valley bottom from the Gavins Point Dam near Yankton, South Dakota to the mouth of the Missouri River near St. Louis, Missouri (river miles 811–0). The LCPI provides a systematic index of wetness potential and soil moisture-retention potential of the valley-bottom lands by combining the interactions among water-surface elevations, land-surface elevations, and the inherent moisture-retention capability of soils. A nine-class wetness index was generated by intersecting a digital elevation model for the valley bottom with sloping water-surface elevation planes derived from eight modeled discharges. The flow-recurrence index was then intersected with eight soil-drainage classes assigned to soils units in the digital Soil Survey Geographic (SSURGO) Database (Soil Survey Staff, 2010) to create a 72-class index of potential flow-recurrence and moisture-retention capability of Missouri River valley-bottom lands. The LCPI integrates the fundamental abiotic factors that determine long-term suitability of land for various uses, particularly those relating to vegetative communities and their associated values. Therefore, the LCPI provides a mechanism allowing planners, land managers, landowners, and other stakeholders to assess land-use capability based on the physical properties of the land, in order to guide future land-management decisions. This report documents data compilation for the LCPI in a revised and expanded, 72-class version for the Lower Missouri River valley bottom, and inclusion of additional soil attributes to allow users flexibility in exploring land capabilities.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMGC33C..07F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMGC33C..07F"><span>Climate Variability: Adaptation Strategies for Colorado River Management</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fulp, T. J.; Prairie, J. R.</p> <p>2008-12-01</p> <p>The importance of the Colorado River system to the western United States and the Republic of Mexico is well documented. Much has been written recently in response to the lingering drought and increasing demands on the system. Questions such as "has the river run out of water?", "how low can it go?", and "will Lake Mead go dry?" express the concern that the river system will be hard-pressed to continue to meet future demands, particularly if droughts tend toward increased magnitudes and longer durations. Reservoirs on the main stream of the Colorado River are managed by the Bureau of Reclamation (Reclamation), on behalf of the Secretary of the U.S. Department of the Interior (Secretary). Over 80% of the 60 million acre-feet of storage capacity is contained in Lake Powell and Lake Mead, large reservoirs that are located in each of the sub-basins (Upper Basin and Lower Basin) defined in the 1922 Colorado River Compact. In response to the worst drought conditions in approximately one hundred years of recorded history and the lack of specific operational guidelines for operation of Lake Powell and Lake Mead for drought and low reservoir conditions, the Secretary adopted new operational guidelines in December 2007 that will be used for an interim period (through 2026). The Interim Guidelines were the result of an intense, three-year effort in accordance with the National Environmental Policy Act of 1969 (NEPA). Several alternative operational rules were compared with respect to future potential impacts to Colorado River resources, including lake levels, water delivery, hydropower production, water quality, recreation, and fish and wildlife and published in an Environmental Impact Statement (EIS). Due to the large uncertainty regarding future inflows into the system, particularly in a changing climate, these comparisons were presented in probabilistic terms in order to assess the risk of key events (e.g., the timing and magnitude of water shortages). Because it is impossible to precisely predict future inflows, a range of possible inflows were analyzed and used to quantify the uncertainty with respect to inflows, which by far dominates the overall uncertainty. Although Reclamation had typically used a technique that resamples the historical record to generate future hydrologic inflow scenarios, new techniques were used in this EIS in order to better quantify the uncertainties. These techniques were the outcome of a multi-faceted research and development program begun in 2004 to enable the use of other methods for projecting possible future inflow sequences for Colorado River planning studies. The techniques employed in this EIS included resampling from a new paleo-reconstruction of Colorado River flows dating back to 762 A.D. and a hybrid technique that couples the state information derived from the paleo-record (i.e., wet, dry) with the historical record to generate future sequences that have not been seen in the past. Additional research is both needed and warranted to better quantify the uncertainties and the risks of current and future water resource management decisions and Reclamation is continuing its research effort, working with other governmental agencies and universities, to further its ability to use climate information in its decision-making.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H32C..05B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H32C..05B"><span>A conceptual model for groundwater - surface water interactions in the Darling River Floodplain, N.S.W., Australia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brodie, R. S.; Lawrie, K.; Somerville, P.; Hostetler, S.; Magee, J.; Tan, K. P.; Clarke, J.</p> <p>2013-12-01</p> <p>Multiple lines of evidence were used to develop a conceptual model for interaction between the Darling River and associated floodplain aquifers in western New South Wales, Australia. Hydrostratigraphy and groundwater salinities were mapped using airborne electromagnetics (AEM), validated by sonic-core drilling. The AEM was highly effective in mapping groundwater freshening due to river leakage in discrete zones along the river corridor. These fresh resources occurred in both the unconfined Quaternary aquifers and the underlying, largely semi-confined Pliocene aquifers. The AEM was also fundamental to mapping the Blanchetown Clay aquitard which separates these two aquifer systems. Major-ion chemistry highlighted a mixing signature between river waters and groundwaters in both the Quaternary and Pliocene aquifers. Stable isotope data indicates that recharge to the key Pliocene aquifers is episodic and linked to high-flow flood events rather than river leakage being continuous. This was also evident when groundwater chemistry was compared with river chemistry under different flow conditions. Mapping of borehole levels showed groundwater mounding near the river, emphasising the regional significance of losing river conditions for both aquifer systems. Critically, rapid and significant groundwater level responses were measured during large flood events. In the Pliocene aquifers, continuation of rising trends after the flood peak receded confirms that this is an actual recharge response rather than hydraulic loading. The flow dependency of river leakage can be explained by the presence of mud veneers and mineral precipitates along the Darling River channel bank when river flows are low. During low flow conditions these act as impediments to river leakage. During floods, high flow velocities scour these deposits, revealing lateral-accretion surfaces in the shallow scroll plain sediments. This scouring allows lateral bank recharge to the shallow aquifer. During flood recession, mud veneers are re-deposited while transient return flows from bank storage results in carbonate precipitation in river banks. Active recharge of the Pliocene aquifers requires leakage pathways through the overlying Blanchetown Clay. Neogene-to-Present tectonic modification of the alluvial sequence, including discrete fault offsets in the Blanchetown Clay, was identified in the AEM data. Mapped faults are coincident with structures mapped in LiDAR, airborne magnetics, regional gravity, and seismic data.The study highlighted the utility of AEM in mapping the critical geological controls on groundwater-surface interaction, including the previously unrecognised tectonic influences on the largely unconsolidated alluvial sequence. Flow-dependent recharge due to changing river bed conductance has implications for groundwater assessment and management. An analysis of historic river flows suggests that active recharge would only occur for about 17% of the time when flow exceeds about 9,000 ML/d. Recharge would be negligible with groundwater extraction during low-flow conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70048055','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70048055"><span>Antecedent flow conditions and nitrate concentrations in the Mississippi River basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Murphy, Jennifer C.; Hirsch, Robert M.; Sprague, Lori A.</p> <p>2014-01-01</p> <p>The relationship between antecedent flow conditions and nitrate concentrations was explored at eight sites in the 2.9 million square kilometers (km2) Mississippi River basin, USA. Antecedent flow conditions were quantified as the ratio between the mean daily flow of the previous year and the mean daily flow from the period of record (Qratio), and the Qratio was statistically related to nitrate anomalies (the unexplained variability in nitrate concentration after filtering out season, long-term trend, and contemporaneous flow effects) at each site. Nitrate anomaly and Qratio were negatively related at three of the four major tributary sites and upstream in the Mississippi River, indicating that when mean daily streamflow during the previous year was lower than average, nitrate concentrations were higher than expected. The strength of these relationships increased when data were subdivided by contemporaneous flow conditions. Five of the eight sites had significant negative relationships (p ≤ 0.05) at high or moderately high contemporaneous flows, suggesting nitrate that accumulates in these basins during a drought is flushed during subsequent high flows. At half of the sites, when mean daily flow during the previous year was 50 percent lower than average, nitrate concentration can be from 9 to 27 percent higher than nitrate concentrations that follow a year with average mean daily flow. Conversely, nitrate concentration can be from 8 to 21 percent lower than expected when flow during the previous year was 50 percent higher than average. Previously documented for small, relatively homogenous basins, our results suggest that relationships between antecedent flows and nitrate concentrations are also observable at a regional scale. Relationships were not observed (using all contemporaneous flow data together) for basins larger than 1 million km2, suggesting that above this limit the overall size and diversity within these basins may necessitate the use of more complicated statistical approaches or that there may be no discernible basin-wide relationship with antecedent flow. The relationships between nitrate concentration and Qratio identified in this study serve as the basis for future studies that can better define specific hydrologic processes occurring during and after a drought (or high flow period) which influence nitrate concentration, such as the duration or magnitude of low flows, and the timing of low and high flows.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1973/0153/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1973/0153/report.pdf"><span>A preliminary evaluation of regional ground-water flow in south-central Washington</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>La Sala, A. M.; Doty, G.C.; Pearson, F.J.</p> <p>1973-01-01</p> <p>The characteristics of regional ground-water flow were investigated in a 4,500-square-mile region of south-central Washington, centered on the U.S. Atomic Energy Commission Hanford Reservation. The investigation is part of the Commission's feasibility study on storing high-level radioactive waste in chambers mined in basaltic rocks at a. depth of about 3,000 feet or more below the surface. Ground-water flow., on a regional scale, occurs principally in the basalt and-in interbedded sediments of the Columbia River Group, and is controlled by topography, the structure of the basalt, and the large streams--the Columbia, Snake, and Yakima Rivers. The ground water beneath the main part of the Hanford Reservation, south and west of the Columbia River, inures southeastward from recharge areas in the uplands, including Cold Creek and Dry Creek valleys, and ultimately discharges to the Columbia River south of the reservation: East and southeast of the Columbia River, ground water flows generally southwestward and discharges to the River. The Yakima River valley contains a distinct flow system in which movement is toward the Yakima River from the topographic divides. A large southward-flowing ground-water system beneath the southern flank of the Horse Heaven Hills discharges to the Columbia River in the westward-trending reach downstream from Wallula Gap.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/5618908-potential-modified-flow-release-rules-kingsley-dam-meeting-crane-habitat-requirements-platte-river-nebraska','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5618908-potential-modified-flow-release-rules-kingsley-dam-meeting-crane-habitat-requirements-platte-river-nebraska"><span>Potential of modified flow-release rules for Kingsley Dam in meeting crane habitat requirements, Platte River, Nebraska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Shen, H.W.; Hiew, K.L.; Loubser, E.</p> <p>1985-11-01</p> <p>The Whooping Crane, an endangered species, uses the Platte River downstream from Overton, Nebraska in its migratory route. Maintenance of favorable habitat conditions required by law may mean restrictions on development and management of Colorado's entitled water in the South Platte River. The project investigated meeting crane habitat flow requirements by alternative plans for flow releases through Kingsley Dam (North Platte River) and Narrows Dam (a proposed project on the South Platte River). The analysis is based on mean monthly flow of the past 39 years. Irrigation releases were held firm, hydroelectric power production was maximized, and flows available tomore » meet habitat requirements were determined. A simulation model was developed to model the operation of the North Platte and South Platte Rivers.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013WRR....49.4817M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013WRR....49.4817M"><span>A novel approach to flow estimation in tidal rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moftakhari, H. R.; Jay, D. A.; Talke, S. A.; Kukulka, T.; Bromirski, P. D.</p> <p>2013-08-01</p> <p>Reliable estimation of river discharge to the ocean from large tidal rivers is vital for water resources management and climate analyses. Due to the difficulties inherent in measuring tidal-river discharge, flow records are often limited in length and/or quality and tidal records often predate discharge records. Tidal theory indicates that tides and river discharge interact through quadratic bed friction, which diminishes and distorts the tidal wave as discharge increases. We use this phenomenon to develop a method of estimating river discharge for time periods with tidal data but no flow record. Employing sequential 32 day harmonic analyses of tidal properties, we calibrate San Francisco (SF), CA tide data to the Sacramento River delta outflow index from 1930 to 1990, and use the resulting relationship to hindcast river flow from 1858 to 1929. The M2 admittance (a ratio of the observed M2 tidal constituent to its astronomical forcing) best reproduces high flows, while low-flow periods are better represented by amplitude ratios based on higher harmonics (e.g.,M4/M22). Results show that the annual inflow to SF Bay is now 30% less than before 1900 and confirm that the flood of January 1862 was the largest since 1858.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNG31A1837A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNG31A1837A"><span>Derivation and Application of Idealized Flow Conditions in River Network Simulation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Afshari Tork, S.; Fekete, B. M.</p> <p>2015-12-01</p> <p>Stream flow information is essential for many applications across broad range of scales, e.g. global water balances, engineering design, flood forecasting, environmental management, etc. Quantitative assessment of flow dynamics of natural streams, requires detailed knowledge of all the geometrical and geophysical variables (e.g. bed-slope, bed roughness, etc.) along river reaches. Simplifying the river bed geometries could reduce both the computational burden implementing flow simulations and challenges in assembling the required data, especially for large domains. Average flow conditions expressed as empirical "at-a-station" hydraulic geometry relationships between key channel components, (i.e. water depth, top-width, flow velocity, flow area against discharge) have been studied since 60's. Recent works demonstrated that power-function as idealized riverbed geometry whose parameters are correlated to those of exponential relationship between mean water depth and top-width, are consistent with empirical "at-a-station" relations.US Geological Surveys' National Water Information System web-interface provides huge amount of river discharge and corresponding stage height data from several thousands of streamflow monitoring stations over United States accompanied by river survey summaries providing additional flow informations (width, mean velocity, cross-sectional area). We conducted a series of analyses to indentify consistent data daily monitoring and corresponding survey records that are suitable to refine our current understanding of how the "at-a-station" properties of river channels relate to channel forming characteristics (e.g. riverbed slope, flow regime, geology, etc.). The resulting ~1,200 actively operating USGS stations with over ~225,000 corresponding survery records (almost 200 survey per gauge on average) is the largest river survey database ever studied in the past.Our presentation will show our process assembling our river monitoring and survey data base and we will present our first results translating "at-a-station" relations into he hydraulic geometry of river channels based on idealized power-law riverbed geometries. We also will also present a series of application (e.g. improved flow rounting, simplyfied river surveying).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.5183C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.5183C"><span>Explore the impacts of river flow and quality on biodiversity for water resources management by AI techniques</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chang, Fi-John; Tsai Tsai, Wen-Ping; Chang, Li-Chiu</p> <p>2016-04-01</p> <p>Water resources development is very challenging in Taiwan due to her diverse geographic environment and climatic conditions. To pursue sustainable water resources development, rationality and integrity is essential for water resources planning. River water quality and flow regimes are closely related to each other and affect river ecosystems simultaneously. This study aims to explore the complex impacts of water quality and flow regimes on fish community in order to comprehend the situations of the eco-hydrological system in the Danshui River of northern Taiwan. To make an effective and comprehensive strategy for sustainable water resources management, this study first models fish diversity through implementing a hybrid artificial neural network (ANN) based on long-term observational heterogeneity data of water quality, stream flow and fish species in the river. Then we use stream flow to estimate the loss of dissolved oxygen based on back-propagation neural networks (BPNNs). Finally, the non-dominated sorting genetic algorithm II (NSGA-II) is established for river flow management over the Shihmen Reservoir which is the main reservoir in this study area. In addition to satisfying the water demands of human beings and ecosystems, we also consider water quality for river flow management. The ecosystem requirement takes the form of maximizing fish diversity, which can be estimated by the hybrid ANN. The human requirement is to provide a higher satisfaction degree of water supply while the water quality requirement is to reduce the loss of dissolved oxygen in the river among flow stations. The results demonstrate that the proposed methodology can offer diversified alternative strategies for reservoir operation and improve reservoir operation strategies for producing downstream flows that could better meet both human and ecosystem needs as well as maintain river water quality. Keywords: Artificial intelligence (AI), Artificial neural networks (ANNs), Non-dominated sorting genetic algorithm II (NSGA-II), Sustainable water resources management, Flow regime, River ecosystem.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70017392','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70017392"><span>Critical and supercritical flows in two unstable, mountain rivers, Toutle river system, Washington</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Simon, Andrew; Hardison, J. H.</p> <p>1994-01-01</p> <p>Critical and supercritical flows are generally considered to be rare occurrences in natural river channels. This paper presents data and results pertaining to the existence of measured critical and supercritical flows at gaging stations on the North Fork Toutle River (NFT) and Toutle River main stem (TR). The data set includes 930 discharge measurements made by the staff of the U.S. Geological Survey, Cascades Volcano Observatory, between 1980 and 1989.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1995/4087/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1995/4087/report.pdf"><span>Transport and sources of sediment in the Missouri River between Garrison Dam and the headwaters of Lake Oahe, North Dakota, May 1988 through April 1991</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Berkas, Wayne R.</p> <p>1995-01-01</p> <p>Sediment data were collected on and along the Missouri River downstream from Garrison Dam during May 1988, May 1989, and April 1991 to characterize sediment transport in the river. Specific study objectives were to (1) identify erosional and depositional reaches during two steady-state low-flow periods and one steady-state high-flow period; (2) determine if the reaches are consistently eroding or depositing, regardless of streamflow; and (3) determine the sources of suspended sediment in the river. Erosional and depositional reaches differed between the two low-flow periods, indicating that slight changes in the channel configuration between the two periods caused changes in erosional and depositional patterns. Erosional and depositional reaches also differed between the low-flow periods and the high-flow period, indicating that channel changes and increased streamflow velocities affect erosional and depositional reaches. The significant sources of suspended sediment in the Missouri River are the riverbed and riverbanks. The riverbed contributes to the silt and sand load in the river, and the riverbanks contribute to the clay, silt, and sand load. The contribution from tributaries to the suspendedsediment load in the Missouri River usually is small. Occasionally, during low-flow periods on the Missouri River, the Knife River can contribute significantly to the suspended-sediment load in the Missouri River.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JHyd..556..759L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JHyd..556..759L"><span>Assessing the effects of adaptation measures on optimal water resources allocation under varied water availability conditions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Dedi; Guo, Shenglian; Shao, Quanxi; Liu, Pan; Xiong, Lihua; Wang, Le; Hong, Xingjun; Xu, Yao; Wang, Zhaoli</p> <p>2018-01-01</p> <p>Human activities and climate change have altered the spatial and temporal distribution of water availability which is a principal prerequisite for allocation of different water resources. In order to quantify the impacts of climate change and human activities on water availability and optimal allocation of water resources, hydrological models and optimal water resource allocation models should be integrated. Given that increasing human water demand and varying water availability conditions necessitate adaptation measures, we propose a framework to assess the effects of these measures on optimal allocation of water resources. The proposed model and framework were applied to a case study of the middle and lower reaches of the Hanjiang River Basin in China. Two representative concentration pathway (RCP) scenarios (RCP2.6 and RCP4.5) were employed to project future climate, and the Variable Infiltration Capacity (VIC) hydrological model was used to simulate the variability of flows under historical (1956-2011) and future (2012-2099) conditions. The water availability determined by simulating flow with the VIC hydrological model was used to establish the optimal water resources allocation model. The allocation results were derived under an extremely dry year (with an annual average water flow frequency of 95%), a very dry year (with an annual average water flow frequency of 90%), a dry year (with an annual average water flow frequency of 75%), and a normal year (with an annual average water flow frequency of 50%) during historical and future periods. The results show that the total available water resources in the study area and the inflow of the Danjiangkou Reservoir will increase in the future. However, the uneven distribution of water availability will cause water shortage problems, especially in the boundary areas. The effects of adaptation measures, including water saving, and dynamic control of flood limiting water levels (FLWLs) for reservoir operation, were assessed and implemented to alleviate water shortages. The negative impacts from the South-to-North Water Transfer Project (Middle Route) in the mid-lower reaches of the Hanjiang River Basin can be avoided through the dynamic control of FLWLs in Danjiangkou Reservoir, under the historical and future RCP2.6 and RCP4.5 scenarios. However, the effects of adaptation measures are limited due to their own constraints, such as the characteristics of the reservoirs influencing the FLWLs. The utilization of storm water appears necessary to meet future water demand. Overall, the results indicate that the framework for assessing the effects of adaptation measures on water resources allocation might aid water resources management, not only in the study area but also in other places where water availability conditions vary due to climate change and human activities.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ECSS..189...33V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ECSS..189...33V"><span>An evaluation of climate change effects in estuarine salinity patterns: Application to Ria de Aveiro shallow water system</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vargas, Catarina I. C.; Vaz, Nuno; Dias, João M.</p> <p>2017-04-01</p> <p>It is of global interest, for the definition of effective adaptation strategies, to make an assessment of climate change impacts in coastal environments. In this study, the salinity patterns adjustments and the correspondent Venice System zonations adaptations are evaluated through numerical modelling for Ria de Aveiro, a mesotidal shallow water lagoon located in the Portuguese coast, for the end of the 21st century in a climate change context. A reference (equivalent to present conditions) and three future scenarios are defined and simulated, both for wet and dry conditions. The future scenarios are designed with the following changes to the reference: scenario 1) projected mean sea level (MSL) rise; scenario 2) projected river flow discharges; and scenario 3) projections for both MSL and river flow discharges. The projections imposed are: a MSL rise of 0.42 m; a freshwater flow reduction of ∼22% for the wet season and a reduction of ∼87% for the dry season. Modelling results are analyzed for different tidal ranges. Results indicate: a) a salinity upstream intrusion and a generalized salinity increase for sea level rise scenario, with higher significance in middle-to-upper lagoon zones; b) a maximum salinity increase of ∼12 in scenario 3 and wet conditions for Espinheiro channel, the one with higher freshwater contribution; c) an upstream displacement of the saline fronts occurring in wet conditions for all future scenarios, with stronger expression for scenario 3, of ∼2 km in Espinheiro channel; and d) a landward progression of the saltier physical zones established in the Venice System scheme. The adaptation of the ecosystem to the upstream relocation of physical zones may be blocked by human settlements and other artificial barriers surrounding the estuarine environment.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70028977','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70028977"><span>River-aquifer interactions, geologic heterogeneity, and low-flow management</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fleckenstein, J.H.; Niswonger, R.G.; Fogg, G.E.</p> <p>2006-01-01</p> <p>Low river flows are commonly controlled by river-aquifer exchange, the magnitude of which is governed by hydraulic properties of both aquifer and aquitard materials beneath the river. Low flows are often important ecologically. Numerical simulations were used to assess how textural heterogeneity of an alluvial system influences river seepage and low flows. The Cosumnes River in California was used as a test case. Declining fall flows in the Cosumnes River have threatened Chinook salmon runs. A ground water-surface water model for the lower river basin was developed, which incorporates detailed geostatistical simulations of aquifer heterogeneity. Six different realizations of heterogeneity and a homogenous model were run for a 3-year period. Net annual seepage from the river was found to be similar among the models. However, spatial distribution of seepage along the channel, water table configuration and the level of local connection, and disconnection between the river and aquifer showed strong variations among the different heterogeneous models. Most importantly, the heterogeneous models suggest that river seepage losses can be reduced by local reconnections, even when the regional water table remains well below the riverbed. The percentage of river channel responsible for 50% of total river seepage ranged from 10% to 26% in the heterogeneous models as opposed to 23% in the homogeneous model. Differences in seepage between the models resulted in up to 13 d difference in the number of days the river was open for salmon migration during the critical fall months in one given year. Copyright ?? 2006 The Author(s).</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/1798k/pdf/pp1798k.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/1798k/pdf/pp1798k.pdf"><span>The effects of Missouri River mainstem reservoir system operations on 2011 flooding using a Precipitation-Runoff Modeling System model: Chapter K in 2011 Floods of the Central United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Haj, Adel E.; Christiansen, Daniel E.; Viger, Roland J.</p> <p>2014-01-01</p> <p>In 2011 the Missouri River Mainstem Reservoir System (Reservoir System) experienced the largest volume of flood waters since the initiation of record-keeping in the nineteenth century. The high levels of runoff from both snowpack and rainfall stressed the Reservoir System’s capacity to control flood waters and caused massive damage and disruption along the river. The flooding and resulting damage along the Missouri River brought increased public attention to the U.S. Army Corps of Engineers (USACE) operation of the Reservoir System. To help understand the effects of Reservoir System operation on the 2011 Missouri River flood flows, the U.S. Geological Survey Precipitation-Runoff Modeling System was used to construct a model of the Missouri River Basin to simulate flows at streamgages and dam locations with the effects of Reservoir System operation (regulation) on flow removed. Statistical tests indicate that the Missouri River Precipitation-Runoff Modeling System model is a good fit for high-flow monthly and annual stream flow estimation. A comparison of simulated unregulated flows and measured regulated flows show that regulation greatly reduced spring peak flow events, consolidated two summer peak flow events to one with a markedly decreased magnitude, and maintained higher than normal base flow beyond the end of water year 2011. Further comparison of results indicate that without regulation, flows greater than those measured would have occurred and been sustained for much longer, frequently in excess of 30 days, and flooding associated with high-flow events would have been more severe.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JHyd..562..492R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JHyd..562..492R"><span>Assessing changes in extreme river flow regulation from non-stationarity in hydrological scaling laws</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rodríguez, Estiven; Salazar, Juan Fernando; Villegas, Juan Camilo; Mercado-Bettín, Daniel</p> <p>2018-07-01</p> <p>Extreme flows are key components of river flow regimes that affect manifold hydrological, geomorphological and ecological processes with societal relevance. One fundamental characteristic of extreme flows in river basins is that they exhibit scaling properties which can be identified through scaling (power) laws. Understanding the physical mechanisms behind such scaling laws is a continuing challenge in hydrology, with potential implications for the prediction of river flow regimes in a changing environment and ungauged basins. After highlighting that the scaling properties are sensitive to environmental change, we develop a physical interpretation of how temporal changes in scaling exponents relate to the capacity of river basins to regulate extreme river flows. Regulation is defined here as the basins' capacity to either dampen high flows or to enhance low flows. Further, we use this framework to infer temporal changes in the regulation capacity of five large basins in tropical South America. Our results indicate that, during the last few decades, the Amazon river basin has been reducing its capacity to enhance low flows, likely as a consequence of pronounced environmental change in its south and south-eastern sub-basins. The proposed framework is widely applicable to different basins, and provides foundations for using scaling laws as empirical tools for inferring temporal changes of hydrological regulation, particularly relevant for identifying and managing hydrological consequences of environmental change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=64459&Lab=NHEERL&keyword=Methodological+AND+study&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=64459&Lab=NHEERL&keyword=Methodological+AND+study&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>DETECTING FOREST STRESS AND DECLINE IN RESPONSE TO INCREASING RIVER FLOW IN SOUTHWEST FLORIDA, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Forest stress and decline resulting from increased river flows were investigated in Myakka River State Park (MRSP), Florida, USA. Since 1977, land-use changes around the upper Myakka River watershed have resulted in significant increases in water entering the river, which have...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2010/5121/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2010/5121/"><span>Environmental baseline study of the Huron River Watershed, Baraga and Marquette Counties, Michigan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Woodruff, Laurel G.; Weaver, Thomas L.; Cannon, William F.</p> <p>2010-01-01</p> <p>This report summarizes results of a study to establish water-quality and geochemical baseline conditions within a small watershed in the Lake Superior region. In 2008, the U.S. Geological Survey (USGS) completed a survey of water-quality parameters and soil and streambed sediment geochemistry of the 83 mi2 Huron River Watershed in the Upper Peninsula of Michigan. Streamflow was measured and water-quality samples collected at a range of flow conditions from six sites on the major tributaries of the Huron River. All water samples were analyzed for a suite of common ions, nutrients, and trace metals. In addition, water samples from each site were analyzed for unfiltered total and methylmercury once during summer low-flow conditions. Soil samples were collected from 31 sites, with up to 4 separate samples collected at each site, delineated by soil horizon. Streambed sediments were collected from 11 sites selected to cover most of the area drained by the Huron River system. USGS data were supplemented with ecological assessments completed in 2006 by the Michigan Department of Environmental Quality using a modified version of their Great Lakes Environmental Assessment Section procedure 51, and again during 2008 using volunteers under supervision of the Michigan Department of Natural Resources. Results from this study define a hydrological, geological, and environmental baseline for the Huron River Watershed prior to any significant mineral exploration or development. Results from the project also serve to refine the design of future regional environmental baseline studies in the Lake Superior Basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2010/3123/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2010/3123/"><span>Effects of climate change and land use on water resources in the Upper Colorado River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Belnap, Jayne; Campbell, D.H.</p> <p>2011-01-01</p> <p>The health of the Colorado River watershed is critical to the socioeconomic and ecosystem well-being of the Southwestern United States. Water in springs, streams, and rivers supports a range of aquatic and riparian ecosystems that contain many endangered species. Terrestrial habitats support a wide array of plants and wildlife. In addition, this region is enjoyed by millions of people annually for its recreational and esthetic opportunities. The Colorado River provides water for about 25 million people and is used to irrigate 2.5 million acres of farmland. However, competition for this water is expected to increase as human populations dependent on this water are projected to increase to 38 million by 2020. Climate change is expected to further exacerbate water issues in this region. Drought in the Southwest during 2000-04, caused by both reduced precipitation and a series of the hottest years on record, resulted in streamflows lower than during the 1930s Dust Bowl or the 1950s. Increased temperatures alone are a major factor in reducing surface-water flows in this region. For instance, precipitation received during the winter of 2005 was at the 100-year average. However, low soil moisture and high January-July temperatures resulted in flows that were only 75 percent of average. Climate models predict future warmer temperatures and reduced precipitation in the Upper Colorado River Basin (UCRB), which would reduce water available to humans and ecosystems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27351186','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27351186"><span>Spatio-temporal patterns and factors controlling the hydrogeochemistry of the river Jhelum basin, Kashmir Himalaya.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mir, Riyaz Ahmad; Jeelani, Gh; Dar, Farooq Ahmad</p> <p>2016-07-01</p> <p>River Jhelum is a major source of water for growing population and irrigation in the Kashmir Himalaya. The region is trending towards water scarcity as well as quality deterioration stage due to its highly unregulated development. The existence of few literature on various aspects of the basin prompts us to study the spatio-temporal variability of its physicochemical parameters and thereby to understand the regulating hydrogeochemical mechanisms based on 50 samples collected during high flow (June 2008) and low flow (January 2009) periods. The water chemistry exhibited significant spatial variability reflecting the mixing processes in the basin. The seasonal effect does change the concentration of ions significantly with modest variability in the order of ionic abundance. The Ca(2+) ion among cations and HCO3 (-) ion among anions dominate the ionic budget and correlates significantly with the diverse lithology of the basin. Three major water types, i.e., Ca-Mg-HCO3 (72 %), Ca-HCO3 (12 %), and Mg-Ca-HCO3 (16 %), suggest that the chemical composition of water is dominantly controlled by carbonate lithology, besides a significant contribution from silicates. However, at certain sites, the biological processes and anthropogenic activities play a major role. Relatively, the lower ionic concentration during high flow period (summer season) suggested the significant influence of higher discharge via dilution effect. The higher discharge due to higher rainfall and snow melting in response to rising temperature in this period leads to strong flushing of human and agricultural wastes into the river. The factor analysis also reflected the dominant control of varied lithology and anthropogenic sources on the water quality based on the four significant factors explaining collectively about 70-81 % of the total data variance. A two-member chloride mixing model used to estimate the discharge contribution of tributaries to the main river channel showed reliable results. It may be mentioned that the regular and continuous contamination through anthropogenic sources is likely to jeopardize and degrade the water quality in the near future. Thus, critical management approaches and strategies are very imperative for its future sustainability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.water.usgs.gov/wri014135','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/wri014135"><span>Steady-state flow distribution and monthly flow duration in selected branches of St. Clair and Detroit rivers within the Great Lakes waterway</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Holtschlag, D.J.; Koschik, J.A.</p> <p>2001-01-01</p> <p>St. Clair and Detroit Rivers are connecting channels between Lake Huron and Lake Erie in the Great Lakes waterway, and form part of the boundary between the United States and Canada. St. Clair River, the upper connecting channel, drains 222,400 square miles and has an average flow of about 182,000 cubic feet per second. Water from St. Clair River combines with local inflows and discharges into Lake St. Clair before flowing into Detroit River. In some reaches of St. Clair and Detroit Rivers, islands and dikes split the flow into two to four branches. Even when the flow in a reach is known, proportions of flows within individual branches of a reach are uncertain. Simple linear regression equations, subject to a flow continuity constraint, are developed to provide estimators of these proportions and flows. The equations are based on 533 paired measurements of flow in 13 reaches forming 31 branches. The equations provide a means for computing the expected values and uncertainties of steady-state flows on the basis of flow conditions specified at the upstream boundaries of the waterway. In 7 upstream reaches, flow is considered fixed because it can be determined on the basis of flows specified at waterway boundaries and flow continuity. In these reaches, the uncertainties of flow proportions indicated by the regression equations can be used directly to determine the uncertainties of the corresponding flows. In the remaining 6 downstream reaches, flow is considered uncertain because these reaches do not receive flow from all the branches of an upstream reach, or they receive flow from some branches of more than one upstream reach. Monte Carlo simulation analysis is used to quantify this increase in uncertainty associated with the propagation of uncertainties from upstream reaches to downstream reaches. To eliminate the need for Monte Carlo simulations for routine calculations, polynomial regression equations are developed to approximate the variation in uncertainties as a function of flow at the headwaters of St. Clair River. Finally, monthly flow-duration data on the main channels of St. Clair and Detroit Rivers are used with the equations developed in this report to estimate the steady-state flow-duration characteristics of selected branches.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70179746','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70179746"><span>Flow reconstructions in the Upper Missouri River Basin using riparian tree rings</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Schook, Derek M.; Friedman, Jonathan M.; Rathburn, Sara L.</p> <p>2016-01-01</p> <p>River flow reconstructions are typically developed using tree rings from montane conifers that cannot reflect flow regulation or hydrologic inputs from the lower portions of a watershed. Incorporating lowland riparian trees may improve the accuracy of flow reconstructions when these trees are physically linked to the alluvial water table. We used riparian plains cottonwoods (Populus deltoides ssp. monilifera) to reconstruct discharge for three neighboring rivers in the Upper Missouri River Basin: the Yellowstone (n = 389 tree cores), Powder (n = 408), and Little Missouri Rivers (n = 643). We used the Regional Curve Standardization approach to reconstruct log-transformed discharge over the 4 months in early summer that most highly correlated to tree ring growth. The reconstructions explained at least 57% of the variance in historical discharge and extended back to 1742, 1729, and 1643. These are the first flow reconstructions for the Lower Yellowstone and Powder Rivers, and they are the furthest downstream among Rocky Mountain rivers in the Missouri River Basin. Although mostly free-flowing, the Yellowstone and Powder Rivers experienced a shift from early-summer to late-summer flows within the last century. This shift is concurrent with increasing irrigation and reservoir storage, and it corresponds to decreased cottonwood growth. Low-frequency flow patterns revealed wet conditions from 1870 to 1980, a period that includes the majority of the historical record. The 1816–1823 and 1861–1865 droughts were more severe than any recorded, revealing that drought risks are underestimated when using the instrumental record alone.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1917880L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1917880L"><span>Estimated cumulative sediment trapping in future hydropower reservoirs in Africa</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lucía, Ana; Berlekamp, Jürgen; Zarfl, Christiane</p> <p>2017-04-01</p> <p>Despite a rapid economic development in Sub-Saharan Africa, almost 70% of the human population in this area remain disconnected from electricity access (International Energy Agency 2011). Mitigating climate change and a search for renewable, "climate neutral" electricity resources are additional reasons why Africa will be one key centre for future hydropower dam building, with only 8% of the technically feasible hydropower potential actually exploited. About 300 major hydropower dams with a total capacity of 140 GW are currently under construction (11.4%) or planned (88.6%) (Zarfl et al. 2015). Despite the benefits of hydropower dams, fragmentation of the rivers changes the natural flow, temperature and sediment regime. This has consequences for a high number of people that directly depend on the primary sector linked to rivers and floodplains. But sediment trapping in the reservoir also affects dam operation and decreases its life span. Thus, the objective of this work is to quantify the dimension of sediment trapping by future hydropower dams in African river basins. Soil erosion is described with the universal soil loss equation (Wischmeier & Smith 1978) and combined with the connectivity index (Cavalli et al. 2013) to estimate the amount of eroded soil that reaches the fluvial network and finally ends up in the existing (Lehner et al. 2011) and future reservoirs (Zarfl et al. 2015) per year. Different scenarios assuming parameter values from the literature are developed to include model uncertainty. Estimations for existing dams will be compared with literature data to evaluate the applied estimation method and scenario assumptions. Based on estimations for the reservoir volume of the future dams we calculated the potential time-laps of the future reservoirs due to soil erosion and depending on their planned location. This approach could support sustainable decision making for the location of future hydropower dams. References Cavalli, M., Trevisani, S., Comiti, F., & Marchi, L. (2013). Geomorphometric assessment of spatial sediment connectivity in small Alpine catchments. Geomorphology, 188, 31-41. Lehner, B., Liermann, C. R., Revenga, C., Vörösmarty, C., Fekete, B., Crouzet, P., Döll, P., Endejan, M., Frenken, K., Magome, J., Nilsson, C., Robertson, J.C., Rödel, R., Sindorf , N., & Wisser, D. (2011). High-resolution mapping of the world's reservoirs and dams for sustainable river-flow management. Frontiers in Ecology and the Environment, 9(9), 494-502. Wischmeier, W. H. and D. D. Smith. (1978). Predicting rainfall erosion losses: guide to conservation planning. USDA, Agriculture Handbook 537. U.S. Government Printing Office, Washington, DC. Zarfl, C., Lumsdon, A. E., Berlekamp, J., Tydecks, L., & Tockner, K. (2015). A global boom in hydropower dam construction. Aquatic Sciences, 77(1), 161-170.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H53E1757B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H53E1757B"><span>Assessment of Environmental Flows for the Rivers of Western Ganges Delta with Special Reference to Indian Sundarban</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhadra, T.; Hazra, S.; Ghosh, S.; Barman, B. C.</p> <p>2016-12-01</p> <p>The Indian Sundarban, situated on the western tide-dominated part of the Ganges delta was formed by the sedimentation of the Ganges and its tributaries. Freshwater is a scarce resource in the Sundarban though it is traversed by rivers. Most of the rivers of Western Ganges Delta, which used to nourish the Sundarban, have become defunct with the passage of time. To ensure sustainable flow and to enhance the flow-dependent ecosystem services in this region, assessment of environmental flows within the system is required. A pilot assessment of environment flows, supported by IUCN has been carried out in some specific river reaches of Western Ganges Delta under the present study. The holistic Building Block Methodology (BBM) has been modified and used for the assessment of environmental flows. In the modified BBM, three distinctive blocks namely Hydro-Morphology, Ecology and Socio-Economy have been selected and indicators like Ganges Dolphin (Platanista gangetica), Sundari tree (Heritiera fomes) and Hilsa fish (Tenualosa ilisha) etc. have been determined to assess the environmental flows. As the discharge data of the selected rivers are restricted in the public domain, the SWAT model has been run to generate the discharge data of the classified rivers. The Hydraulic model, HEC-RAS has been calibrated in the selected River reaches to assess the habitat availability and its changes for indicator species under different flow condition. The study reveals that River Bhagirathi-Hugli requires 150-427 cumec additional water in monsoon and 850-1127 cumec additional water in post-monsoon months for Hilsa migration, whereas 327-486 cumec additional water in pre-monsoon and dry season and 227-386 cumec additional water in post-monsoon months are required for Dolphin movement. Flow requirement of river Ichhamati has also been estimated under the present study. The total required flow for the Sundarban ecosystem to reduce the salinity level from 30ppt to 14ppt during the dry and pre-monsoon months has been estimated as 1700 cumec. The pilot study observes that the present level of flow in the river systems is inadequate to sustain the ecosystem function and the in-stream flow requirement is more than the presently available flow. Keyword: Building Block Methodology, Environmental Flows, HEC-RAS, Indian Sundarban, SWAT.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70185508','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70185508"><span>Decreased runoff response to precipitation, Little Missouri River Basin, northern Great Plains, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Griffin, Eleanor R.; Friedman, Jonathan M.</p> <p>2017-01-01</p> <p>High variability in precipitation and streamflow in the semiarid northern Great Plains causes large uncertainty in water availability. This uncertainty is compounded by potential effects of future climate change. We examined historical variability in annual and growing season precipitation, temperature, and streamflow within the Little Missouri River Basin and identified differences in the runoff response to precipitation for the period 1976-2012 compared to 1939-1975 (n = 37 years in both cases). Computed mean values for the second half of the record showed little change (<5%) in annual or growing season precipitation, but average annual runoff at the basin outlet decreased by 22%, with 66% of the reduction in flow occurring during the growing season. Our results show a statistically significant (p < 0.10) 27% decrease in the annual runoff response to precipitation (runoff ratio). Surface-water withdrawals for various uses appear to account for <12% of the reduction in average annual flow volume, and we found no published or reported evidence of substantial flow reduction caused by groundwater pumping in this basin. Results of our analysis suggest that increases in monthly average maximum and minimum temperatures, including >1°C increases in January through March, are the dominant driver of the observed decrease in runoff response to precipitation in the Little Missouri River Basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC43G..02W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC43G..02W"><span>Climate Variability over India and Bangladesh from the Perturbed UK Met Office Hadley Model: Impacts on Flow and Nutrient Fluxes in the Ganges Delta System</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Whitehead, P. G.; Caesar, J.; Crossman, J.; Barbour, E.; Ledesma, J.; Futter, M. N.</p> <p>2015-12-01</p> <p>A semi-distributed flow and water quality model (INCA- Integrated Catchments Model) has been set up for the whole of the Ganges- Brahmaputra- Meghna (GBM) River system in India and Bangladesh. These massive rivers transport large fluxes of water and nutrients into the Bay of Bengal via the GBM Delta system in Bangladesh. Future climate change will impact these fluxes with changing rainfall, temperature, evapotranspiration and soil moisture deficits being altered in the catchment systems. In this study the INCA model has been used to assess potential impacts of climate change using the UK Met Office Hadley Centre GCM model linked to a regionally coupled model of South East Asia, covering India and Bangladesh. The Hadley Centre model has been pururbed by varying the parameters in the model to generate 17 realisations of future climates. Some of these reflect expected change but others capture the more extreme potential behaviour of future climate conditions. The 17 realisations have been used to drive the INCA Flow and Nitrogen model inorder to generate downstream times series of hydrology and nitrate- nitrogen. The variability of the climates on these fluxes are investigated and and their likley impact on the Bay of Begal Delta considered. Results indicate a slight shift in the monsoon season with increased wet season flows and increased temperatures which alter nutrient fluxes. Societal Importance to Stakeholders The GBM Delta supports one of the most densely populated regions of people living in poverty, who rely on ecosystem services provided by the Delta for survival. These ecosystem services are dependent upon fluxes of water and nutrients. Freshwater for urban, agriculture, and aquaculture requirements are essential to livelihoods. Nutrient loads stimulate estuarine ecosystems, supporting fishing stocks, which contribute significantly the economy of Bangladesh. Thus the societal importance of upstream climate driven change change in Bangladesh are very significant to many stakeholders in Bangladesh at the local, regional and national levels.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2017/5048/sir20175048.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2017/5048/sir20175048.pdf"><span>Groundwater resources of the Devils Postpile National Monument—Current conditions and future vulnerabilities</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Evans, William C.; Bergfeld, Deborah</p> <p>2017-06-15</p> <p>This study presents an extensive database on groundwater conditions in and around Devils Postpile National Monument. The database contains chemical analyses of springs and the monument water-supply well, including major-ion chemistry, trace element chemistry, and the first information on a list of organic compounds known as emerging contaminants. Diurnal, seasonal, and annual variations in groundwater discharge and chemistry are evaluated from data collected at five main monitoring sites, where streams carry the aggregate flow from entire groups of springs. These springs drain the Mammoth Mountain area and, during the fall months, contribute a significant fraction of the San Joaquin River flow within the monument. The period of this study, from fall 2012 to fall 2015, includes some of the driest years on record, though the seasonal variability observed in 2013 might have been near normal. The spring-fed streams generally flowed at rates well below those observed during a sequence of wet years in the late 1990s. However, persistence of flow and reasonably stable water chemistry through the recent dry years are indicative of a sizeable groundwater system that should provide a reliable resource during similar droughts in the future. Only a few emerging contaminants were detected at trace levels below 1 microgram per liter (μg/L), suggesting that local human visitation is not degrading groundwater quality. No indication of salt from the ski area on the north side of Mammoth Mountain could be found in any of the groundwaters. Chemical data instead show that natural mineral water, such as that discharged from local soda springs, is the main source of anomalous chloride in the monument supply well and in the San Joaquin River. The results of the study are used to develop a set of recommendations for future monitoring to enable detection of deleterious impacts to groundwater quality and quantity</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.water.usgs.gov/sir20045130/','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/sir20045130/"><span>Simulation of ground-water flow in the Cedar River alluvial aquifer flow system, Cedar Rapids, Iowa</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Turco, Michael J.; Buchmiller, Robert C.</p> <p>2004-01-01</p> <p>Model results indicate that the primary sources of inflow to the modeled area are infiltration from the Cedar River (53.0 percent) and regional flow in the glacial and bedrock materials (34.1 percent). The primary sources of outflow from the modeled area are discharge to the Cedar River (45.4 percent) and pumpage (44.8 percent). Current steady-state pumping rates have increased the flow of water from the Cedar River to the alluvial aquifer by 43.8 cubic feet per second. Steady-state and transient hypothetical pumpage scenarios were used to show the relation between changes in pumpage and changes in infiltration of water from the Cedar River. Results indicate that more than 99 percent of the water discharging from municipal wells infiltrates from the Cedar River, that the time required for induced river recharge to equilibrate with municipal pumpage may be 150 days or more, and that ground-water availability in the Cedar Rapids area will not be significantly affected by doubling current pumpage as long as there is sufficient flow in the Cedar River to provide recharge.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2007/1146/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2007/1146/"><span>Estimated Magnitudes and Recurrence Intervals of Peak Flows on the Mousam and Little Ossipee Rivers for the Flood of April 2007 in Southern Maine</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hodgkins, Glenn A.; Stewart, Gregory J.; Cohn, Timothy A.; Dudley, Robert W.</p> <p>2007-01-01</p> <p>Large amounts of rain fell on southern Maine from the afternoon of April 15, 2007, to the afternoon of April 16, 2007, causing substantial damage to houses, roads, and culverts. This report provides an estimate of the peak flows on two rivers in southern Maine--the Mousam River and the Little Ossipee River--because of their severe flooding. The April 2007 estimated peak flow of 9,230 ft3/s at the Mousam River near West Kennebunk had a recurrence interval between 100 and 500 years; 95-percent confidence limits for this flow ranged from 25 years to greater than 500 years. The April 2007 estimated peak flow of 8,220 ft3/s at the Little Ossipee River near South Limington had a recurrence interval between 100 and 500 years; 95-percent confidence limits for this flow ranged from 50 years to greater than 500 years.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.usgs.gov/wri/1997/4128/report.pdf','USGSPUBS'); return false;" href="http://pubs.usgs.gov/wri/1997/4128/report.pdf"><span>Low-flow characteristics and profiles for the Deep River in the Cape Fear River basin, North Carolina</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Weaver, J.C.</p> <p>1997-01-01</p> <p>Drainage area and low-flow discharge profiles are presented for the Deep River. The drainage-area profile shows downstream increases in basin size. At the mouth, the drainage area for the Deep River is 1,441 square miles. Low-flow discharge profiles for the Deep River include 7Q10, 30Q2, W7Q10, and 7Q2 discharges in a continuous profile with contributions from major tributaries included.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSEC41A..08X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSEC41A..08X"><span>Dujiangyan: Could the ancient hydraulic engineering be a sustainable solution for Mississippi River diversions?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Y. J.</p> <p>2016-02-01</p> <p>Dujiangyan, also known as the Dujiangyan Project, is a hydraulic engineering complex built more than 2260 years ago on the Mingjiang River near Chengdu in China's Sichuan Province. The complex splits the river into two channels, a so-called "inner river" (Leijiang) and an "outer river" (Waijiang) that carry variable water volumes and sediment loads under different river flow conditions. The inner river and its numerous distributary canals are primarily man-made for irrigation over the past 2000 years, while the outer river is the natural channel and flows southward before entering into the Yangtze River. Under normal flow, 60% of the Mingjiang River goes into the inner river for irrigating nearly 1 million hectares of agricultural land on the Chengdu plain. During floods, however, less than 40% of the Mingjiang River flows into the inner river. Under both flow conditions, about 80% of the riverine sediments is carried by the outer river and continues downstream. This hydrology is achieved through a weir work complex that comprises three major components: a V-shaped bypass dike in the center of the Mingjiang River (the Yuzui Bypass Dike, see photo below), a sediment diversion canal in the inner river below the bypass dike (the Feishayan Floodgate), and a flow control in the inner river below the sediment diversion canal (the Baopingkou Diversion Passage). Together with ancillary embankments, these structures have not only ensured a regular supply of silt-reduced water to the fertile Chengdu plain, but have provided great benefits in flood control, sediment transport, and water resources regulation over the past two thousand years. The design of this ancient hydraulic complex ingeniously conforms to the natural environment while incorporating many sophisticated techniques, reflecting the concept that humankind is an integral part of nature. As we are urgently seeking solutions today to save the sinking Mississippi River Delta, examination of the ancient engineering marvel may offer insights into sustainable practices in river engineering of the lower Mississippi under climate change and sea level rise. This paper will introduce the Dujiangyan Project and will discuss possibilities of applying Dujiangyan's fundamental concept for sediment diversions in the Lower Mississippi River.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001Geo....29..655K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001Geo....29..655K"><span>Simulation of turbid underflows generated by the plunging of a river</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kassem, Ahmed; Imran, Jasim</p> <p>2001-07-01</p> <p>When the density of sediment-laden river water exceeds that of the lake or ocean into which it discharges, the river plunges to the bottom of the receiving water body and continues to flow as a hyperpycnal flow. These particle-laden underflows, also known as turbidity currents, can travel remarkable distances and profoundly influence the seabed morphology from shoreline to abyss by depositing, eroding, and dispersing large quantities of sediment particles. Here we present a new approach to investigating the transformation of a plunging river flow into a turbidity current. Unlike previous workers using experimental and numerical treatments, we consider the evolution of a turbidity current from a river as different stages of a single flow process. From initial commotion to final stabilization, the transformation of a river (open channel flow) into a density-driven current (hyperpycnal flow) is captured in its entirety by a numerical model. Successful implementation of the model in laboratory and field cases has revealed the dynamics of a complex geophysical flow that is extremely difficult to observe in the field or model in the laboratory.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011HESSD...8.3743B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011HESSD...8.3743B"><span>Prediction of future hydrological regimes in poorly gauged high altitude basins: the case study of the upper Indus, Pakistan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bocchiola, D.; Diolaiuti, G.; Soncini, A.; Mihalcea, C.; D'Agata, C.; Mayer, C.; Lambrecht, A.; Rosso, R.; Smiraglia, C.</p> <p>2011-04-01</p> <p>In the mountain regions of the Hindu Kush, Karakoram and Himalaya (HKH) the "third polar ice cap" of our planet, glaciers play the role of "water towers" by providing significant amount of melt water, especially in the dry season, essential for agriculture, drinking purposes, and hydropower production. Recently, most glaciers in the HKH have been retreating and losing mass, mainly due to significant regional warming, thus calling for assessment of future water resources availability for populations down slope. However, hydrology of these high altitude catchments is poorly studied and little understood. Most such catchments are poorly gauged, thus posing major issues in flow prediction therein, and representing in facts typical grounds of application of PUB concepts, where simple and portable hydrological modeling based upon scarce data amount is necessary for water budget estimation, and prediction under climate change conditions. In this preliminarily study, future (2060) hydrological flows in a particular watershed (Shigar river at Shigar, ca. 7000 km2), nested within the upper Indus basin and fed by seasonal melt from major glaciers, are investigated. The study is carried out under the umbrella of the SHARE-Paprika project, aiming at evaluating the impact of climate change upon hydrology of the upper Indus river. We set up a minimal hydrological model, tuned against a short series of observed ground climatic data from a number of stations in the area, in situ measured ice ablation data, and remotely sensed snow cover data. The future, locally adjusted, precipitation and temperature fields for the reference decade 2050-2059 from CCSM3 model, available within the IPCC's panel, are then fed to the hydrological model. We adopt four different glaciers' cover scenarios, to test sensitivity to decreased glacierized areas. The projected flow duration curves, and some selected flow descriptors are evaluated. The uncertainty of the results is then addressed, and use of the model for nearby catchments discussed. The proposed approach is valuable as a tool to investigate the hydrology of poorly gauged high altitude areas, and to project forward their hydrological behavior pending climate change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011HESS...15.2059B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011HESS...15.2059B"><span>Prediction of future hydrological regimes in poorly gauged high altitude basins: the case study of the upper Indus, Pakistan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bocchiola, D.; Diolaiuti, G.; Soncini, A.; Mihalcea, C.; D'Agata, C.; Mayer, C.; Lambrecht, A.; Rosso, R.; Smiraglia, C.</p> <p>2011-07-01</p> <p>In the mountain regions of the Hindu Kush, Karakoram and Himalaya (HKH) the "third polar ice cap" of our planet, glaciers play the role of "water towers" by providing significant amount of melt water, especially in the dry season, essential for agriculture, drinking purposes, and hydropower production. Recently, most glaciers in the HKH have been retreating and losing mass, mainly due to significant regional warming, thus calling for assessment of future water resources availability for populations down slope. However, hydrology of these high altitude catchments is poorly studied and little understood. Most such catchments are poorly gauged, thus posing major issues in flow prediction therein, and representing in fact typical grounds of application of PUB concepts, where simple and portable hydrological modeling based upon scarce data amount is necessary for water budget estimation, and prediction under climate change conditions. In this preliminarily study, future (2060) hydrological flows in a particular watershed (Shigar river at Shigar, ca. 7000 km2), nested within the upper Indus basin and fed by seasonal melt from major glaciers, are investigated. The study is carried out under the umbrella of the SHARE-Paprika project, aiming at evaluating the impact of climate change upon hydrology of the upper Indus river. We set up a minimal hydrological model, tuned against a short series of observed ground climatic data from a number of stations in the area, in situ measured ice ablation data, and remotely sensed snow cover data. The future, locally adjusted, precipitation and temperature fields for the reference decade 2050-2059 from CCSM3 model, available within the IPCC's panel, are then fed to the hydrological model. We adopt four different glaciers' cover scenarios, to test sensitivity to decreased glacierized areas. The projected flow duration curves, and some selected flow descriptors are evaluated. The uncertainty of the results is then addressed, and use of the model for nearby catchments discussed. The proposed approach is valuable as a tool to investigate the hydrology of poorly gauged high altitude areas, and to project forward their hydrological behavior pending climate change.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.1302W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.1302W"><span>Potential impacts of damming the Juba Valley, western Somalia: Insights from geomorphology and alluvial history</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Williams, Martin</p> <p>2014-05-01</p> <p>In 1988 plans were well advanced to dam the Juba River in western Somalia. The aims of the Baardheere Dam Project were to generate hydroelectric power for the capital Mogadishu, and to provide water for irrigation in the Juba Valley. A reconnaissance survey on foot along 500 km of the river upstream of the proposed dam site at Baardheere and detailed geomorphic mapping from air photos provided a basis for reconstructing the late Quaternary alluvial history of the river and for assessing the potential impact of the proposed dam. The Juba River rises in the Ethiopian Highlands and is the only river in Somalia that flows to the sea. Its history reflects climatic events in Ethiopia, where the Rift Valley lakes were very low during the LGM (21±2 ka), and high for about 5, 000 years before and after then. Cave deposits in Somalia indicate wetter conditions at 13, 10, 7.5 and 1.5 ka. Alluvial terraces in the Juba Valley range in age from late Pleistocene to late Holocene but only attain a few metres above the present floodplain. This is because the dry tributary valleys contain limestone caves and fissures that divert any high flows from the parent river underground, a process not known when the project was first approved. The oldest preserved terrace was cemented by calcrete by 40 ka. Alluvial gravels were deposited at the outlet of dry tributary valleys during times of episodic high-energy flow between 26 ka and 28 ka. Finely laminated shelly sands accumulated at 10 ka to form the 5 m terrace. The 2 m terrace was laid down 3.2 ka ago as a slackwater deposit. The lack of high-level alluvial terraces raises doubts over plans to dam the river, since rapid leakage would occur from side valleys and the reservoir would not attain the height needed to generate hydroelectric power. It would submerge all existing arable land along the river. Finally, the presence in the late Holocene alluvium of the sub-fossil gastropods Bulinus truncatus and Biomphalaria pfeifferi, which are the two main vectors of schistosomiasis in northeast Africa, suggests that this parasitic disease could become endemic across the valley. Any future plans to manage the Juba River need to take proper account of alluvial history and geomorphic processes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Geomo.302...92R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Geomo.302...92R"><span>Fluvial fluxes from the Magdalena River into Cartagena Bay, Caribbean Colombia: Trends, future scenarios, and connections with upstream human impacts</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Restrepo, Juan D.; Escobar, Rogger; Tosic, Marko</p> <p>2018-02-01</p> <p>Fluxes of continental runoff and sediments as well as downstream deposition of eroded soils have severely altered the structure and function of fluvial and deltaic-estuarine ecosystems. The Magdalena River, the main contributor of continental fluxes into the Caribbean Sea, delivers important amounts of water and sediments into Cartagena Bay, a major estuarine system in northern Colombia. Until now, trends in fluvial fluxes into the bay, as well as the relationship between these tendencies in fluvial inputs and associated upstream changes in the Magdalena catchment, have not been studied. Here we explore the interannual trends of water discharge and sediment load flowing from the Magdalena River-Canal del Dique system into Cartagena Bay during the last three decades, forecast future scenarios of fluxes into the bay, and discuss possible connections between observed trends in fluvial inputs and trends in human intervention in the Magdalena River basin. Significant upward trends in annual runoff and sediment load during the mid-1980s, 1990s, and post-2000 are observed in the Magdalena and in the Canal del Dique flowing into Cartagena Bay. During the last decade, Magdalena streamflow and sediment load experienced increases of 24% and 33%, respectively, compared to the pre-2000 year period. Meanwhile, the Canal del Dique witnessed increases in water discharge and sediment load of 28% and 48%, respectively. During 26 y of monitoring, the Canal del Dique has discharged 177 Mt of sediment to the coastal zone, of which 52 Mt was discharged into Cartagena Bay. Currently, the Canal drains 6.5% and transports 5.1% of the Magdalena water discharge and sediment load. By 2020, water discharge and sediment flux from the Canal del Dique flowing to the coastal zone will witness increments of 164% and 260%, respectively. Consequently, sediment fluxes into Cartagena Bay will witness increments as high as 8.2 Mt y- 1 or 317%. Further analyses of upstream sediment load series for 21 tributary systems of the main Magdalena during the 2005-2010 period reveal that six tributaries, representing 55% of the analyzed Magdalena basin area, have witnessed increasing trends in sediment load, raising the river's sediment load by 44 Mt y- 1. Overall, trends in sediment load of the Magdalena and the Canal del Dique during the last three decades are in close agreement with the observed trends in human induced upstream erosion. The last decade has witnessed even stronger increments in fluvial fluxes to Cartagena Bay. Our results emphasize the importance of the catchment-coast linkage in order to predict future changes of fluvial fluxes into Caribbean estuarine systems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.acs.org/doi/abs/10.1021/es201221s','USGSPUBS'); return false;" href="http://pubs.acs.org/doi/abs/10.1021/es201221s"><span>Nitrate in the Mississippi River and its tributaries, 1980 to 2008: Are we making progress?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sprague, Lori A.; Hirsch, Robert M.; Aulenbach, Brent T.</p> <p>2011-01-01</p> <p>Changes in nitrate concentration and flux between 1980 and 2008 at eight sites in the Mississippi River basin were determined using a new statistical method that accommodates evolving nitrate behavior over time and produces flow-normalized estimates of nitrate concentration and flux that are independent of random variations in streamflow. The results show that little consistent progress has been made in reducing riverine nitrate since 1980, and that flow-normalized concentration and flux are increasing in some areas. Flow-normalized nitrate concentration and flux increased between 9 and 76% at four sites on the Mississippi River and a tributary site on the Missouri River, but changed very little at tributary sites on the Ohio, Iowa, and Illinois Rivers. Increases in flow-normalized concentration and flux at the Mississippi River at Clinton and Missouri River at Hermann were more than three times larger than at any other site. The increases at these two sites contributed much of the 9% increase in flow-normalized nitrate flux leaving the Mississippi River basin. At most sites, concentrations increased more at low and moderate streamflows than at high streamflows, suggesting that increasing groundwater concentrations are having an effect on river concentrations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21413685','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21413685"><span>Batteries for efficient energy extraction from a water salinity difference.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>La Mantia, Fabio; Pasta, Mauro; Deshazer, Heather D; Logan, Bruce E; Cui, Yi</p> <p>2011-04-13</p> <p>The salinity difference between seawater and river water is a renewable source of enormous entropic energy, but extracting it efficiently as a form of useful energy remains a challenge. Here we demonstrate a device called "mixing entropy battery", which can extract and store it as useful electrochemical energy. The battery, containing a Na(2-x)Mn(5)O(10) nanorod electrode, was shown to extract energy from real seawater and river water and can be applied to a variety of salt waters. We demonstrated energy extraction efficiencies of up to 74%. Considering the flow rate of river water into oceans as the limiting factor, the renewable energy production could potentially reach 2 TW, or ∼13% of the current world energy consumption. The mixing entropy battery is simple to fabricate and could contribute significantly to renewable energy in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JHyd..454...56O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JHyd..454...56O"><span>A potential approach for low flow selection in water resource supply and management</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ouyang, Ying</p> <p>2012-08-01</p> <p>SummaryLow flow selections are essential to water resource management, water supply planning, and watershed ecosystem restoration. In this study, a new approach, namely the frequent-low (FL) approach (or frequent-low index), was developed based on the minimum frequent-low flow or level used in minimum flows and/or levels program in northeast Florida, USA. This FL approach was then compared to the conventional 7Q10 approach for low flow selections prior to its applications, using the USGS flow data from the freshwater environment (Big Sunflower River, Mississippi) as well as from the estuarine environment (St. Johns River, Florida). Unlike the FL approach that is associated with the biological and ecological impacts, the 7Q10 approach could lead to the selections of extremely low flows (e.g., near-zero flows) that may hinder its use for establishing criteria to prevent streams from significant harm to biological and ecological communities. Additionally, the 7Q10 approach could not be used when the period of data records is less than 10 years by definition while this may not the case for the FL approach. Results from both approaches showed that the low flows from the Big Sunflower River and the St. Johns River decreased as time elapsed, demonstrating that these two rivers have become drier during the last several decades with a potential of salted water intrusion to the St. Johns River. Results from the FL approach further revealed that the recurrence probability of low flow increased while the recurrence interval of low flow decreased as time elapsed in both rivers, indicating that low flows occurred more frequent in these rivers as time elapsed. This report suggests that the FL approach, developed in this study, is a useful alternative for low flow selections in addition to the 7Q10 approach.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMOS33A1430B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMOS33A1430B"><span>Hydrological Controls on Dissolved Organic Matter Quality and Export in a Coastal River System in Southeastern USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhattacharya, R.; Osburn, C. L.</p> <p>2017-12-01</p> <p>Dissolved organic matter (DOM) exported from river catchments can influence the biogeochemical processes in coastal environments with implications for water quality and carbon budget. High flow conditions are responsible for most DOM export ("pulses") from watersheds, and these events reduce DOM transformation and production by "shunting" DOM from river networks into coastal waters: the Pulse-Shunt Concept (PSC). Subsequently, the source and quality of DOM is also expected to change as a function of river flow. Here, we used stream dissolved organic carbon concentrations ([DOC]) along with DOM optical properties, such as absorbance at 350 nm (a350) and fluorescence excitation and emission matrices modeled by parallel factor analysis (PARAFAC), to characterize DOM source, quality and fluxes under variable flow conditions for the Neuse River, a coastal river system in the southeastern US. Observations were made at a flow gauged station above head of tide periodically between Aug 2011 and Feb 2013, which captured low flow periods in summer and several high flow events including Hurricane Irene. [DOC] and a350 were correlated and varied positively with river flow, implying that a large portion of the DOM was colored, humic and flow-mobilized. During high flow conditions, PARAFAC results demonstrated the higher influx of terrestrial humic DOM, and lower in-stream phytoplankton production or microbial degradation. However, during low flow, DOM transformation and production increased in response to higher residence times and elevated productivity. Further, 70% of the DOC was exported by above average flows, where 3-4 fold increases in DOC fluxes were observed during episodic events, consistent with PSC. These results imply that storms dramatically affects DOM export to coastal waters, whereby high river flow caused by episodic events primarily shunt terrestrial DOM to coastal waters, whereas low flow promotes in-stream DOM transformation and amendment with microbial DOM.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JVGR..171..201M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JVGR..171..201M"><span>The ~ 2500 yr B.P. Chicoral non-cohesive debris flow from Cerro Machín Volcano, Colombia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murcia, H. F.; Hurtado, B. O.; Cortés, G. P.; Macías, J. L.; Cepeda, H.</p> <p>2008-04-01</p> <p>Cerro Machín Volcano (CMV) is located in the central part of the Colombian Andes (2750 m asl), 150 km southwest of Bogotá. It is considered the most dangerous active volcano of Colombia. CMV has experienced at least six major explosive eruptions during the last 5000 years. These eruptions have emplaced many types of pyroclastic deposits with associated lahars that have traveled more than 100 km. One of these lahars is called Chicoral Debris Flow Deposit (DFD2). This deposit is exposed as discontinuous terraces (3-20 m thick) along the Coello and Magdalena rivers up to 109 km from the source. The DFD2 covers a minimum area of 62 km 2 and has a minimum volume of 0.57 km 3. It comprises two dacite-rich volcaniclastic units. Grain-size analysis reveals that the matrix content and sorting increase with distance while the average grain size decreases. The clay content of the DFD2 matrix is approximately 1%, thus categorizing it as a non-cohesive debris flow. Radiocarbon dates obtained from underlying and overlying paleosols yielded ages of 2505 + 65 and 1640 + 45 yr B.P., respectively. These dates suggest that DFD2 is related to the ~ 2600 yr B.P. El Guaico eruption of CMV. This eruption produced a block-and-ash flow that filled and blocked the Toche River up to 5 km from the volcano. Subsequent remobilization of this loose material by runoff water generated a massive debris flow that traveled 91 km along the Toche and Coello rivers and continued across the Espinal Alluvial Fan debouching into the Magdalena River where it continued another 18 km prior to its transformation into a sediment-laden flow. Because the last eruption of the volcano occurred ca. 900 years ago, no historic activity of CMV is known among inhabitants of the region. Hence the region has developed without awareness of volcanic hazards. Therefore an assessment of volcanic hazards is essential for understanding and evaluating the vulnerability and risk to which people are exposed in case of a future eruption. Such assessment is critical for urban planning, development, contingency, emergency and education planning.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1815483M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1815483M"><span>Groundwater vulnerability to climate variability: modelling experience and field observations in the lower Magra Valley (Liguria, Italy)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Menichini, Matia; Doveri, Marco; El Mansoury, Bouabid; El Mezouary, Lhoussaine; Lelli, Matteo; Raco, Brunella; Scozzari, Andrea; Soldovieri, Francesco</p> <p>2016-04-01</p> <p>The aquifer of the Lower Magra Valley (SE Liguria, Italy) extends in a flat plain, where two main rivers (Magra and Vara) flow. These rivers are characterized by a wide variation of water level and water chemical composition (TDS, Cl and SO4) due to the combination of rainfall regime and the presence of thermal springs in the inner part of the catchment area. Groundwater flow is apparently controlled by stream water infiltration, which affects both water levels and water quality. In particular, the wide range of variation of some particular chemical species in the stream water influences the groundwater chemistry on a seasonal basis. In the area of interest, there is an important well-field, which supplies most of the drinking water to the nearby city of La Spezia. In this context, the groundwater system is exposed to a high degree of vulnerability, both in terms of quality and quantity. This study is aimed to develop a predictive flow and transport model in order to assess the vulnerability s.l. of the Magra Valley aquifer system and to evaluate its behaviour in awaited climate scenarios. A flow and transport model was developed by using MODFLOW and MT3DMS codes, and it's been calibrated in both steady state and transient conditions. The model confirmed the importance of the Magra river in the water balance and chemical composition of the extracted groundwater. In addition, a data-driven modelling approach was applied in order to determine boundary conditions (e.g. rivers and constant head or general head boundaries) of the physical model under hypothetic future climate scenarios. For this purpose, fully synthetic datasets have been generated as a training set of the data-driven scheme, with input variables inspired by selected climate models and input/output relationships estimated by past observations. An experimental run of the flow-transport model for 30 years ahead was performed, based on such hypothetic scenarios. This approach highlighted how the groundwater flow of the studied aquifer is highly vulnerable and sensitive to climate conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018E%26ES..140a2035Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018E%26ES..140a2035Z"><span>Daily River Flow Forecasting with Hybrid Support Vector Machine – Particle Swarm Optimization</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zaini, N.; Malek, M. A.; Yusoff, M.; Mardi, N. H.; Norhisham, S.</p> <p>2018-04-01</p> <p>The application of artificial intelligence techniques for river flow forecasting can further improve the management of water resources and flood prevention. This study concerns the development of support vector machine (SVM) based model and its hybridization with particle swarm optimization (PSO) to forecast short term daily river flow at Upper Bertam Catchment located in Cameron Highland, Malaysia. Ten years duration of historical rainfall, antecedent river flow data and various meteorology parameters data from 2003 to 2012 are used in this study. Four SVM based models are proposed which are SVM1, SVM2, SVM-PSO1 and SVM-PSO2 to forecast 1 to 7 day ahead of river flow. SVM1 and SVM-PSO1 are the models with historical rainfall and antecedent river flow as its input, while SVM2 and SVM-PSO2 are the models with historical rainfall, antecedent river flow data and additional meteorological parameters as input. The performances of the proposed model are measured in term of RMSE and R2 . It is found that, SVM2 outperformed SVM1 and SVM-PSO2 outperformed SVM-PSO1 which meant the additional meteorology parameters used as input to the proposed models significantly affect the model performances. Hybrid models SVM-PSO1 and SVM-PSO2 yield higher performances as compared to SVM1 and SVM2. It is found that hybrid models are more effective in forecasting river flow at 1 to 7 day ahead at the study area.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.H53K..01F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.H53K..01F"><span>Parameterizing a Large-scale Water Balance Model in Regions with Sparse Data: The Tigris-Euphrates River Basins as an Example</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flint, A. L.; Flint, L. E.</p> <p>2010-12-01</p> <p>The characterization of hydrologic response to current and future climates is of increasing importance to many countries around the world that rely heavily on changing and uncertain water supplies. Large-scale models that can calculate a spatially distributed water balance and elucidate groundwater recharge and surface water flows for large river basins provide a basis of estimates of changes due to future climate projections. Unfortunately many regions in the world have very sparse data for parameterization or calibration of hydrologic models. For this study, the Tigris and Euphrates River basins were used for the development of a regional water balance model at 180-m spatial scale, using the Basin Characterization Model, to estimate historical changes in groundwater recharge and surface water flows in the countries of Turkey, Syria, Iraq, Iran, and Saudi Arabia. Necessary input parameters include precipitation, air temperature, potential evapotranspiration (PET), soil properties and thickness, and estimates of bulk permeability from geologic units. Data necessary for calibration includes snow cover, reservoir volumes (from satellite data and historic, pre-reservoir elevation data) and streamflow measurements. Global datasets for precipitation, air temperature, and PET were available at very large spatial scales (50 km) through the world scale databases, finer scale WorldClim climate data, and required downscaling to fine scales for model input. Soils data were available through world scale soil maps but required parameterization on the basis of textural data to estimate soil hydrologic properties. Soil depth was interpreted from geomorphologic interpretation and maps of quaternary deposits, and geologic materials were categorized from generalized geologic maps of each country. Estimates of bedrock permeability were made on the basis of literature and data on driller’s logs and adjusted during calibration of the model to streamflow measurements where available. Results of historical water balance calculations throughout the Tigris and Euphrates River basins will be shown along with details of processing input data to provide spatial continuity and downscaling. Basic water availability analysis for recharge and runoff is readily available from a determinisitic solar radiation energy balance model and a global potential evapotranspiration model and global estimates of precipitation and air temperature. Future climate estimates can be readily applied to the same water and energy balance models to evaluate future water availability for countries around the globe.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H34E..03L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H34E..03L"><span>Cryospheric Change Impacts on Alpine Hydrology: Combining Model With Observations in the Upper Reaches of Hei River, China</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, X.; Chen, R.; Wang, G.; Liu, J.; Yang, Y.; Han, C.; Song, Y.; Liu, Z.; Kang, E.</p> <p>2017-12-01</p> <p>Cryospheric change impacts largely on alpine hydrology but they are still unclear owing to rare observations and suitable models in the Western Cold Regions of China (WCRC), where many large rivers including almost inland rivers originate and some of them flow to adjacent countries. The upstream of the inland river provides nearly almost water resources to the arid mid-downstream areas, such as the Hei River. Based on the long term field observation in WCRC, a Cryospheric Basin Hydrological Model (CBHM) was created to evaluate the cryospheric impacts on streamflow in the upper reaches of Hei river (UHR), and relationships between Cryosphere and streamflow were further discussed by using measured data. The NorESM1-ME were chosen to project future streamflow under scenarios RCP2.6, RCP4.5 and RCP8.5. The monthly basin runoff in UHR was simulated with a coefficient of efficiency about 0.93 and 0.94, and a mass balance error about 2.5% and -0.2% during the calibration period from 1960 to 1990 and validation period from 1991 to 2013, respectively. The CBHM results were then well validated by measured evapotranspiration (ET), soil temperature, glacier area, water balance of land covers etc. in UHR. It found that the moraine-talus region was the major runoff contribution (60.5%) area though its area proportion was only about 20%, whereas the total runoff contribution of meadow and grassland was only about 27% but their area ratio was about 70% in UHR. Glacier and snow cover contributed 3.5% and 25.4% fresh water in average to streamflow during 1960 to 2013 in HUR. Owing to the increased air temperature (2.9 oC/54a) and precipitation (69.2 mm/54a) in the past 54 years, glacial and snow melting runoff increased 9.8% and 12.1%, respectively. The air temperature rise decreased and brought forward the snowmelt flood peak, and increased the winter flow due to permafrost degradation in UHR. Glaciers would disappear in the near future owing to its small size and increasing air temperature, but the snow melting runoff would increase due to increasing snowfall in the higher mountainous areas in UHR. In the basins with small glacial runoff ratio such as UHR in WCRC, the basin runoff would increase or change a little in the future according to the water balance between the increasing rainfall and snowfall runoff and evapotranspiration.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26927961','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26927961"><span>Impacts of climate change, land-use change and phosphorus reduction on phytoplankton in the River Thames (UK).</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bussi, Gianbattista; Whitehead, Paul G; Bowes, Michael J; Read, Daniel S; Prudhomme, Christel; Dadson, Simon J</p> <p>2016-12-01</p> <p>Potential increases of phytoplankton concentrations in river systems due to global warming and changing climate could pose a serious threat to the anthropogenic use of surface waters. Nevertheless, the extent of the effect of climatic alterations on phytoplankton concentrations in river systems has not yet been analysed in detail. In this study, we assess the impact of a change in precipitation and temperature on river phytoplankton concentration by means of a physically-based model. A scenario-neutral methodology has been employed to evaluate the effects of climate alterations on flow, phosphorus concentration and phytoplankton concentration of the River Thames (southern England). In particular, five groups of phytoplankton are considered, representing a range of size classes and pigment phenotypes, under three different land-use/land-management scenarios to assess their impact on phytoplankton population levels. The model results are evaluated within the framework of future climate projections, using the UK Climate Projections 09 (UKCP09) for the 2030s. The results of the model demonstrate that an increase in average phytoplankton concentration due to climate change is highly likely to occur, with the magnitude varying depending on the location along the River Thames. Cyanobacteria show significant increases under future climate change and land use change. An expansion of intensive agriculture accentuates the growth in phytoplankton, especially in the upper reaches of the River Thames. However, an optimal phosphorus removal mitigation strategy, which combines reduction of fertiliser application and phosphorus removal from wastewater, can help to reduce this increase in phytoplankton concentration, and in some cases, compensate for the effect of rising temperature. Copyright © 2016 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H33B1537B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H33B1537B"><span>Monitoring and Mapping Off-Channel Water Quality in the Willamette River, Oregon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buccola, N. L.; Rounds, S. A.; Smith, C.; Anderson, C.; Jones, K.; Mangano, J.; Wallick, R.</p> <p>2016-12-01</p> <p>The floodplain of the Willamette River in northwestern Oregon includes remnant slower-moving sloughs, side-channels, and alcoves that provide rearing habitat and potential cool-water sources for native cold-water fish species, such as the federally threatened Chinook salmon. The mapping and characterization of the hydraulics and water sources of these off-channel areas is the first step toward protecting and restoring these resources for future generations. A primary focus of this study is to determine how flow management can increase the habitat value of these off-channel areas, especially during summer low-flow periods when water temperatures in the main channel regularly exceed lethal temperatures for salmonids. The U.S. Geological Survey, in cooperation with U.S. Army Corps of Engineers and Oregon State University, has been measuring the characteristics of off-channel water quality in the Willamette River under a variety of water levels in summer 2015-16. About 30 diverse off-channel sites within the Willamette floodplain are being monitored and compared with conditions in the main channel. Hourly water temperature, conductivity, and dissolved oxygen (DO) data are being collected at a subset of these sites. Some deep off-channel pools have substantial, consistent cool-water inflows that can dominate locally, allowing them to function as cold-water refuges for salmonids at varying mainstem Willamette flows. Other sloughs have varying characteristics due to intermittent connections to the main channel, depending on river levels. A vibrant community of algae and aquatic macrophytes often coincide with thick layers of fine sediment or organic detritus near the bed, producing low DO zones (<5 mg/L) in many slower-moving off-channel areas. We propose some preliminary hydro-geomorphic categories to better explain cool inflows as sourced from regional groundwater aquifers or localized subsurface river features. A better understanding of the processes governing the presence, location, and type of cold-water refuge areas in a large gravel bed river such as the Willamette River will help inform and guide habitat management and restoration strategies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC51E1131N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC51E1131N"><span>How is the River Water Quality Response to Climate Change Impacts?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nguyen, T. T.; Willems, P.</p> <p>2015-12-01</p> <p>Water quality and its response to climate change have been become one of the most important issues of our society, which catches the attention of many scientists, environmental activists and policy makers. Climate change influences the river water quality directly and indirectly via rainfall and air temperature. For example, low flow decreases the volume of water for dilution and increases the residence time of the pollutants. By contrast, high flow leads to increases in the amount of pollutants and sediment loads from catchments to rivers. The changes in hydraulic characteristics, i.e. water depth and velocity, affect the transportation and biochemical transformation of pollutants in the river water body. The high air temperature leads to increasing water temperature, shorter growing periods of different crops and water demands from domestic households and industries, which eventually effects the level of river pollution. This study demonstrates the quantification of the variation of the water temperature and pollutant concentrations along the Molse Neet river in the North East of Belgium as a result of the changes in the catchment rainfall-runoff, air temperature and nutrient loads. Firstly, four climate change scenarios were generated based on a large ensemble of available global and regional climate models and statistical downscaling based on a quantile perturbation method. Secondly, the climatic changes to rainfall and temperature were transformed to changes in the evapotranspiration and runoff flow through the conceptual hydrological model PDM. Thirdly, the adjustment in nutrient loads from agriculture due to rainfall and growing periods of crops were calculated by means of the semi-empirical SENTWA model. Water temperature was estimated from air temperature by a stochastic model separating the temperature into long-term annual and short-term residual components. Next, hydrodynamic and water quality models of the river, implemented in InfoWorks RS, were simulated for both historical (2000-2010) and projected future periods (2050-2060). The advection movement and physico-biochemical processes were considered for simulation of the following water quality variables: water temperature, dissolved oxygen, biological oxygen demand, ammonium, nitrate, nitrite and organic nitrogen.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1510055D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1510055D"><span>Climate change impact on the management of water resources in the Seine River basin, France</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dorchies, David; Thirel, Guillaume; Chauveau, Mathilde; Jay-Allemand, Maxime; Perrin, Charles; Dehay, Florine</p> <p>2013-04-01</p> <p>It is today commonly accepted that adaptation strategies will be needed to cope with the hydrological consequences of projected climate change. The main objective of the IWRM-Net Climaware project is to design adaptation strategies for various socio-economic sectors and evaluate their relevance at the European scale. Within the project, the Seine case study focuses on dam management. The Seine River basin at Paris (43800km²) shows major socio-economic stakes in France. Due to its important and growing demography, the number of industries depending on water resources or located on the river sides, and the developed agricultural sector, the consequences of droughts and floods may be dramatic. To mitigate the extreme hydrological events, a system of four large multi-purpose reservoirs was built in the upstream part of the basin between 1949 and 1990. The IPCC reports indicate modifications of the climate conditions in northern France in the future. An increase of mean temperature is very likely, and the rainfall patterns could be modified: the uncertainty on future trends is still high, but summer periods could experience lower quantities of rainfall. Anticipating these changes are crucial: will the present reservoirs system be adapted to these conditions? Here we propose to evaluate the capacity of the Seine River reservoirs to withstand future projected climate conditions using the current management rules. For this study a modeling chain was designed. We used two hydrological models: GR4J, a lumped model used as a benchmark, and TGR, a semi-distributed model. TGR was tuned to explicitly account for reservoir management rules. Seven climatic models forced by the moderate A1B IPCC scenario and downscaled using a weather-type method (DSCLIM, Pagé et al., 2009), were used. A quantile-quantile type method was applied to correct bias in climate simulations. A model to mimic the way reservoirs are managed was also developed. The evolution of low flows, high flows and annual flows were assessed under natural condition (i.e. without the inclusion of the reservoirs in the models). Then, the impact of reservoirs and their management were accounted for in the modeling chain. Results will be discussed relatively to future hydro-climatic conditions and current mitigation objectives within the basin. Reference: Pagé, C., L. Terray et J. Boé, 2009: dsclim: A software package to downscale climate scenarios at regional scale using a weather-typing based statistical methodology. Technical Report TR/CMGC/09/21, SUC au CERFACS, URA CERFACS/CNRS No1875, Toulouse, France. Link : http://www.cerfacs.fr/~page/dsclim/dsclim_doc-latest.pdf</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2012/5192/sir2012-5192.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2012/5192/sir2012-5192.pdf"><span>Spatial and seasonal variability of base flow in the Verde Valley, central Arizona, 2007 and 2011</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Garner, Bradley D.; Bills, Donald J.</p> <p>2012-01-01</p> <p>Synoptic base-flow surveys were conducted on streams in the Verde Valley, central Arizona, in June 2007 and February 2011 by the U.S. Geological Survey (USGS), in cooperation with the Verde River Basin Partnership, the Town of Clarkdale, and Yavapai County. These surveys, also known as seepage runs, measured streamflow under base-flow conditions at many locations over a short period of time. Surveys were conducted on a segment of the Verde River that flows through the Verde Valley, between USGS streamflow-gaging stations 09504000 and 09506000, a distance of 51 river miles. Data from the surveys were used to investigate the dominant controls on Verde River base flow, spatial variability in gaining and losing reaches, and the effects that human alterations have on base flow in the surface-water system. The most prominent human alterations in the Verde Valley are dozens of surface-water diversions from streams, including gravity-fed ditch diversions along the Verde River.Base flow that entered the Verde River from the tributary streams of Oak Creek, Beaver Creek, and West Clear Creek was found to be a major source of base flow in the Verde River. Groundwater discharge directly into the Verde River near these three confluences also was an important contributor of base flow to the Verde River, particularly near the confluence with Beaver Creek. An examination of individual reaches of the Verde River in the Verde Valley found three reaches (largely unaffected by ditch diversions) exhibiting a similar pattern: a small net groundwater discharge in February 2011 (12 cubic feet per second or less) and a small net streamflow loss in June 2007 (11 cubic feet per second or less). Two reaches heavily affected by ditch diversions were difficult to interpret because of the large number of confounding human factors. Possible lower and upper bounds of net groundwater flux were calculated for all reaches, including those heavily affected by ditches.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.1113M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.1113M"><span>Assessment of climate change impacts on meteorological and hydrological droughts in the Jucar River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marcos-Garcia, Patricia; Pulido-Velazquez, Manuel; Lopez-Nicolas, Antonio</p> <p>2016-04-01</p> <p>Extreme natural phenomena, and more specifically droughts, constitute a serious environmental, economic and social issue in Southern Mediterranean countries, common in the Mediterranean Spanish basins due to the high temporal and spatial rainfall variability. Drought events are characterized by their complexity, being often difficult to identify and quantify both in time and space, and an universally accepted definition does not even exist. This fact, along with future uncertainty about the duration and intensity of the phenomena on account of climate change, makes necessary increasing the knowledge about the impacts of climate change on droughts in order to design management plans and mitigation strategies. The present abstract aims to evaluate the impact of climate change on both meteorological and hydrological droughts, through the use of a generalization of the Standardized Precipitation Index (SPI). We use the Standardized Flow Index (SFI) to assess the hydrological drought, using flow time series instead of rainfall time series. In the case of the meteorological droughts, the Standardized Precipitation and Evapotranspiration Index (SPEI) has been applied to assess the variability of temperature impacts. In order to characterize climate change impacts on droughts, we have used projections from the CORDEX project (Coordinated Regional Climate Downscaling Experiment). Future rainfall and temperature time series for short (2011-2040) and medium terms (2041-2070) were obtained, applying a quantile mapping method to correct the bias of these time series. Regarding the hydrological drought, the Témez hydrological model has been applied to simulate the impacts of future temperature and rainfall time series on runoff and river discharges. It is a conceptual, lumped and a few parameters hydrological model. Nevertheless, it is necessary to point out the time difference between the meteorological and the hydrological droughts. The case study is the Jucar river basin (Spain), a highly regulated system with a share of 80% of water use for irrigated agriculture. The results show that the climate change would increase the historical drought impacts in the river basin. Acknowledgments The study has been supported by the IMPADAPT project (CGL2013-48424-C2-1-R) with Spanish MINECO (Ministerio de Economía y Competitividad) and European FEDER funds.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16838719','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16838719"><span>Current and future water issues in the Oldman River Basin of Alberta, Canada.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Byrne, J; Kienzle, S; Johnson, D; Duke, G; Gannon, V; Selinger, B; Thomas, J</p> <p>2006-01-01</p> <p>Long-term trends in alpine and prairie snow pack accumulation and melt are affecting streamflow within the Oldman River Basin in southern Alberta, Canada. Unchecked rural and urban development also has contributed to changes in water quality, including enhanced microbial populations and increased waterborne pathogen occurrence. In this study we look at changing environment within the Oldman River Basin and its impact on water quality and quantity. The cumulative effects include a decline in net water supplies, and declining quality resulting in increased risk of disease. Our data indicates that decreases in the rate of flow of water can result in sedimentation of bacterial contaminants within the water column. Water for ecosystems, urban consumption, recreation and distribution through irrigation is often drawn from waterholding facilities such as dams and weirs, and concern must be expressed over the potential for contaminate build-up and disproportionate potential of these structures to pose a risk to human and animal health. With disruption of natural flow rates for water resulting from environmental change such as global warming and/or human intervention, increased attention needs to be paid to use of best management practices to protect source water supplies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H43T..06G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H43T..06G"><span>Improving Water Balance Estimation in the Nile by Combining Remote Sensing and Hydrological Modelling: a Template for Ungauged Basins</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gleason, C. J.; Wada, Y.; Wang, J.</p> <p>2017-12-01</p> <p>Declining gauging infrastructure and fractious water politics have decreased available information about river flows globally, especially in international river basins. Remote sensing and water balance modelling are frequently cited as a potential solutions, but these techniques largely rely on the same in decline gauge data to constrain or parameterize discharge estimates, thus creating a circular approach to estimating discharge inapplicable to ungauged basins. To address this, we here combine a discontinued gauge, remotely sensed discharge estimates made via at-many-stations hydraulic geometry (AMHG) and Landsat data, and the PCR-GLOBWB hydrological model to estimate discharge for an ungauged time period for the Lower Nile (1978-present). Specifically, we first estimate initial discharges from 86 Landsat images and AMHG (1984-2015), and then use these flow estimates to tune the hydrologic model. Our tuning methodology is purposefully simple and can be easily applied to any model without the need for calibration/parameterization. The resulting tuned modelled hydrograph shows large improvement in flow magnitude over previous modelled hydrographs, and validation of tuned monthly model output flows against the historical gauge yields an RMSE of 343 m3/s (33.7%). By contrast, the original simulation had an order-of-magnitude flow error. This improvement is substantial but not perfect: modelled flows have a one-to two-month wet season lag and a negative bias. More sophisticated model calibration and training (e.g. data assimilation) is needed to improve upon our results, however, our results achieved by coupling physical models and remote sensing is a promising first step and proof of concept toward future modelling of ungauged flows. This is especially true as massive cloud computing via Google Earth Engine makes our method easily applicable to any basin without current gauges. Finally, we purposefully do not offer prescriptive solutions for Nile management, and rather hope that the methods demonstrated herein can prove useful to river stakeholders in managing their own water.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2005/5031/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2005/5031/"><span>Water use and availability in the Woonasquatucket and Moshassuck River basins, north-central Rhode Island</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nimiroski, Mark T.; Wild, Emily C.</p> <p>2005-01-01</p> <p>The Woonasquatucket River Basin includes 51.0 square miles, and the Moshassuck River Basin includes 23.8 square miles in north-central Rhode Island. The study area comprises these two basins. The two basins border each other with the Moshassuck River Basin to the northeast of the Woonasquatucket River Basin. Seven towns are in the Woonasquatucket River Basin, and six towns are in the Moshassuck River Basin. To determine the water use and availability in the study area, water supply and discharge data were collected for these river basins for the 1995–99 period, and compared to estimated long-term water available. The study area is unique in the State of Rhode Island, because no withdrawals from major public suppliers were made during the study period. Withdrawals were, therefore, limited to self-supplied domestic use, two minor suppliers, and one self-supplied industrial user. Because no metered data were available, the summer water withdrawals were assumed to be the same as the estimates for the rest of the year. Seven major water suppliers distribute an average of 17.564 million gallons per day for use in the study area from sources outside of the study area. The withdrawals from minor water suppliers were 0.017 million gallons per day in the study area, all in the town of Smithfield in the Woonasquatucket River Basin. The remaining withdrawals in the study area were estimated to be 0.731 million gallons per day by self-supplied domestic, commercial, industrial, and agricultural users. Return flows in the study area included self-disposed water and disposal from permitted dischargers, including the Smithfield Sewage Treatment Plant. Return flows accounted for 4.116 million gallons per day in the study area. Most public-disposed water (15.195 million gallons per day) is collected by the Narragansett Bay Commission and is disposed outside of the basin in Narragansett Bay. The PART program, a computerized hydrograph-separation application, was used at one index stream-gaging station to determine water availability based on the 75th, 50th, and 25th percentiles of the total base flow, the base flow minus the 7-day, 10-year flow criteria, and the base flow minus the Aquatic Base Flow criteria. The index station selected was the Branch River at Forestdale, which is close to the study area and has a similar percentage of sand and gravel area. Water availability was estimated on the basis of baseflow contributions from sand and gravel deposits and till deposits at the index station. Flows were computed for June, July, August, and September 1957–2000, and a percentage of the total flow was determined to come from either sand and gravel deposits, or till, by using a regression equation. The base-flow contributions were converted to a flow per unit area at the station for the till and for the sand and gravel deposits and then applied to the deposits in the study area basins. These values were used to estimate the gross yield of base flow, as well as to subtract the two low flows (7-day, 10-year flow, and Aquatic Base Flow criteria). The results from the Branch River stream-gaging station were lowest in August at the 75th, 50th, and 25th percentile for total flow with either flow criteria subtracted. The estimated August gross yield at the 50th percentile from the Woonasquatucket River Basin was 12.94 million gallons per day, and 5.91 million gallons per day from the Moshassuck River Basin.A ratio was calculated that is equal to total withdrawals divided by water availability. Water-availability flow scenarios at the 75th, 50th, and 25th percentiles for the basins, which are based on total water available from base-flow contributions from till and sand and gravel deposits in the basins, were assessed. The ratios were the highest in July for the 50th percentile estimated gross yield minus Aquatic Base Flow (ABF) flow criteria, where withdrawals are close to the available water. Ratios are not presented if the available water is less than the flow criteria. The ratio of withdrawals to the July gross yield at the 50th percentile minus Aquatic Base Flow was 0.796 for the Woonasquatucket and 0.275 for the Moshassuck River Basin. A long-term hydrologic budget was calculated for the period of 1956–2000 for the Woonasquatucket River Basin and the period of 1964–2000 for the Moshassuck River Basin. The water withdrawals and return flows used in the budget were from 1995 through 1999. For the hydrologic budget, inflow was assumed to equal outflow and was about 120 million gallons per day in the Woonasquatucket River Basin and 56 million gallons per day in the Moshassuck River Basin. The estimated inflows from precipitation and water return flow were 97.3 and 2.7 percent, respectively, in the Woonasquatucket River Basin, and 98.3 and 1.7 percent, respectively, in the Moshassuck River Basin. The estimated outflows from evapotranspiration, streamflow, and water withdrawals were 43.4, 56.1, and 0.5 percent, respectively, in the Woonasquatucket River Basin, and 49.8, 50, and 0.2 percent, respectively, in the Moshassuck River Basin.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27392332','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27392332"><span>Global change impacts on river ecosystems: A high-resolution watershed study of Ebro river metabolism.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Val, Jonatan; Chinarro, David; Pino, María Rosa; Navarro, Enrique</p> <p>2016-11-01</p> <p>Global change is transforming freshwater ecosystems, mainly through changes in basin flow dynamics. This study assessed how the combination of climate change and human management of river flow impacts metabolism of the Ebro River (the largest river basin in Spain, 86,100km(2)), assessed as gross primary production-GPP-and ecosystem respiration-ER. In order to investigate the influence of global change on freshwater ecosystems, an analysis of trends and frequencies from 25 sampling sites of the Ebro river basin was conducted. For this purpose, we examined the effect of anthropogenic flow control on river metabolism with a Granger causality study; simultaneously, took into account the effects of climate change, a period of extraordinary drought (largest in past 140years). We identified periods of sudden flow changes resulting from both human management and global climate effects. From 1998 to 2012, the Ebro River basin was trending toward a more autotrophic condition indicated by P/R ratio. Particularly, the results show that floods that occurred after long periods of low flows had a dramatic impact on the respiration (i.e., mineralization) capacity of the river. This approach allowed for a detailed characterization of the relationships between river metabolism and drought impacts at the watershed level. These findings may allow for a better understanding of the ecological impacts provoked by flow management, thus contributing to maintain the health of freshwater communities and ecosystem services that rely on their integrity. Copyright © 2016 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMPA32A..04W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMPA32A..04W"><span>Future Proofing Water Policy and Catchment Management for a Changing Climate: A Case Study of Competing Demands and Water Scarcity in the River Thames and Catchment</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Whitehead, P. G.; Crossman, J.; Jin, L.</p> <p>2011-12-01</p> <p>The River Thames Catchment is the major water supply system in Southern England and supplies all of London's water supply from either the River Lee (a tributary of the Thames) or the main river abstraction site at Teddington (see Figure 1) or from groundwater sources in London. There has been a measurable change in rainfall patterns over the past 250 years with reducing summer rainfall and, hence flows, over the past 40 years. In 1976, following 3 dry winters, the London Reservoirs were more or less empty and the river flow direction was reversed to ensure a supply of water for London. Recent climate change studies in the Thames catchments suggest an increasing threat to water supply and also damage to river water quality and ecology. In addition to a changing climate, population levels in London have risen in recent years and the catchment is increasingly vulnerable to land use change. Since the 1920s changes in land use have increased the levels of nitrogen and phosphorus in the catchment and this trend is predicted to be exacerbated as climate change reduces freshwater dilution. Also land use is predicted to change as agriculture becomes more intensive as farmers react to higher grain and food prices. At the same time rising water temperatures has exposed the river to the potential for toxic algal blooms, such as cyanobacteria. This doom and gloom story is being managed however using a range of policy instruments, led by central government and public and private organisations such as Thames Water and the Environment Agency. Measures such as new reservoirs, a water transfer scheme from Wales and water metering to reduce demand are all being actively pursued, as are land management measures to control diffuse pollution. In order to assess the effects of climate change on the Thames catchment a major modelling study has been undertaken. The Integrated Catchment Model (INCA) has been set up for the Thames to model flow, nitrogen, phosphorus and ecology. Climate Change simulations predict reduced flow regimes in the river system and changes to the nitrogen patterns. Nitrate is predicted to reduce in summer, due to the lower flows which generate longer water residence times and hence allow more time for denitrification processes to occur. Phosphorus levels increase, however, due to the reduced dilution of effluents with subsequent detrimental effects on ecology. The model has been used to evaluate alternative water management policies such as a new reservoir for London, the transfer of water from the River Severn into the Thames, the reduction in P discharges from Sewage Treatment Works and the control of diffuse runoff by improved land management. Thus using the models to evaluate alternative strategies is very positive contribution to policy and planning.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.......436B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.......436B"><span>Forecasting seasonal hydrologic response in major river basins</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhuiyan, A. M.</p> <p>2014-05-01</p> <p>Seasonal precipitation variation due to natural climate variation influences stream flow and the apparent frequency and severity of extreme hydrological conditions such as flood and drought. To study hydrologic response and understand the occurrence of extreme hydrological events, the relevant forcing variables must be identified. This study attempts to assess and quantify the historical occurrence and context of extreme hydrologic flow events and quantify the relation between relevant climate variables. Once identified, the flow data and climate variables are evaluated to identify the primary relationship indicators of hydrologic extreme event occurrence. Existing studies focus on developing basin-scale forecasting techniques based on climate anomalies in El Nino/La Nina episodes linked to global climate. Building on earlier work, the goal of this research is to quantify variations in historical river flows at seasonal temporal-scale, and regional to continental spatial-scale. The work identifies and quantifies runoff variability of major river basins and correlates flow with environmental forcing variables such as El Nino, La Nina, sunspot cycle. These variables are expected to be the primary external natural indicators of inter-annual and inter-seasonal patterns of regional precipitation and river flow. Relations between continental-scale hydrologic flows and external climate variables are evaluated through direct correlations in a seasonal context with environmental phenomenon such as sun spot numbers (SSN), Southern Oscillation Index (SOI), and Pacific Decadal Oscillation (PDO). Methods including stochastic time series analysis and artificial neural networks are developed to represent the seasonal variability evident in the historical records of river flows. River flows are categorized into low, average and high flow levels to evaluate and simulate flow variations under associated climate variable variations. Results demonstrated not any particular method is suited to represent scenarios leading to extreme flow conditions. For selected flow scenarios, the persistence model performance may be comparable to more complex multivariate approaches, and complex methods did not always improve flow estimation. Overall model performance indicates inclusion of river flows and forcing variables on average improve model extreme event forecasting skills. As a means to further refine the flow estimation, an ensemble forecast method is implemented to provide a likelihood-based indication of expected river flow magnitude and variability. Results indicate seasonal flow variations are well-captured in the ensemble range, therefore the ensemble approach can often prove efficient in estimating extreme river flow conditions. The discriminant prediction approach, a probabilistic measure to forecast streamflow, is also adopted to derive model performance. Results show the efficiency of the method in terms of representing uncertainties in the forecasts.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70037687','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70037687"><span>Determining the effects of dams on subdaily variation in river flows at a whole-basin scale</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Zimmerman, J.K.H.; Letcher, B.H.; Nislow, K.H.; Lutz, K.A.; Magilligan, F.J.</p> <p>2010-01-01</p> <p>River regulation can alter the frequency and magnitude of subdaily flow variations causing major impacts on ecological structure and function. We developed an approach to quantify subdaily flow variation for multiple sites across a large watershed to assess the potential impacts of different dam operations (flood control, run-of-river hydropower and peaking hydropower) on natural communities. We used hourly flow data over a 9-year period from 30 stream gages throughout the Connecticut River basin to calculate four metrics of subdaily flow variation and to compare sites downstream of dams with unregulated sites. Our objectives were to (1) determine the temporal scale of data needed to characterize subdaily variability; (2) compare the frequency of days with high subdaily flow variation downstream of dams and unregulated sites; (3) analyse the magnitude of subdaily variation at all sites and (4) identify individual sites that had subdaily variation significantly higher than unregulated locations. We found that estimates of flow variability based on daily mean flow data were not sufficient to characterize subdaily flow patterns. Alteration of subdaily flows was evident in the number of days natural ranges of variability were exceeded, rather than in the magnitude of subdaily variation, suggesting that all rivers may exhibit highly variable subdaily flows, but altered rivers exhibit this variability more frequently. Peaking hydropower facilities had the most highly altered subdaily flows; however, we observed significantly altered ranges of subdaily variability downstream of some flood-control and run-of-river hydropower dams. Our analysis can be used to identify situations where dam operating procedures could be modified to reduce the level of hydrologic alteration. ?? 2009 John Wiley & Sons, Ltd.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12171360','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12171360"><span>Environmental flows and water quality objectives for the River Murray.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gippel, C; Jacobs, T; McLeod, T</p> <p>2002-01-01</p> <p>Over the past decade, there intense consideration of managing flows in the River Murray to provide environmental benefits. In 1990 the Murray-Darling Basin Ministerial Council adopted a water quality policy: To maintain and, where necessary, improve existing water quality in the rivers of the Murray-Darling Basin for all beneficial uses - agricultural, environmental, urban, industrial and recreational, and in 1994 a flow policy: To maintain and where necessary improve existing flow regimes in the waterways of the Murray-Darling Basin to protect and enhance the riverine environment. The Audit of Water Use followed in 1995, culminating in the decision of the Ministerial Council to implement an interim cap on new diversions for consumptive use (the "Cap") in a bid to halt declining river health. In March 1999 the Environmental Flows and Water Quality Objectives for the River Murray Project (the Project) was set up, primarily to establish be developed that aims to achieve a sustainable river environment and water quality, in accordance with community needs, and including an adaptive approach to management and operation of the River. It will lead to objectives for water quality and environmental flows that are feasible, appropriate, have the support of the scientific, management and stakeholder communities, and carry acceptable levels of risk. This paper describes four key aspects of the process being undertaken to determine the objectives, and design the flow options that will meet those objectives: establishment of an appropriate technical, advisory and administrative framework; establishing clear evidence for regulation impacts; undergoing assessment of environmental flow needs; and filling knowledge gaps. A review of the impacts of flow regulation on the health of the River Murray revealed evidence for decline, but the case for flow regulation as the main cause is circumstantial or uncertain. This is to be expected, because the decline of the River Murray results from many factors acting over a long period. Also, the health of the river varies along its length, from highly degraded to reasonably healthy, so it is clear that different approaches will be needed in the various river zones, with some problems requiring reach or even point scale solutions. Environmental flow needs have been determined through two major Expert Panel reports that identified the ecological priorities for the river. The next step is to translate these needs into feasible flow management actions that will provide the necessary hydrological conditions. Several investigations are underway to recommend options for flow management. Two important investigations are described in this paper: how to enhance flows to wetlands of national and international significance, and how to physically alter or change the operation of structures (including a dam, weir, lock, regulator, barrage or causeway), to provide significant environmental benefits. Early modelling suggests that the only option which has a positive environmental effect in all zones of the River is a reduction in overall water consumption.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=60386&keyword=high+AND+flow+AND+oxygen&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=60386&keyword=high+AND+flow+AND+oxygen&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>WATER QUALITY CHANGES IN HYPORHEIC FLOW AT THE AQUATIC-TERRESTRIAL INTERFACE OF A LARGER RIVER</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Exchange between river water and groundwater in hyporheic flow at the aquatic-terrestrial interface can importantly affect water quality and aquatic habitat in the main channel of large rivers and at off-channel sites that include flowing and stagnant side channels. With tracer ...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.loc.gov/pictures/collection/hh/item/ca3154.photos.194180p/','SCIGOV-HHH'); return false;" href="https://www.loc.gov/pictures/collection/hh/item/ca3154.photos.194180p/"><span>MIDDLE GORGE POWER PLANT, OWENS RIVER STREAM FLOWING OVER TAIL ...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>MIDDLE GORGE POWER PLANT, OWENS RIVER STREAM FLOWING OVER TAIL RACE OF POWER PLANT AND PENSTOCK HEADGATE TO LOWER GORGE CONTROL PLANT. A MINIMAL FLOW OF RIVER WATER IS REQUIRED TO MAINTAIN FISH LIFE - Los Angeles Aqueduct, Middle Gorge Power Plant, Los Angeles, Los Angeles County, CA</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70025651','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70025651"><span>Hydrological alteration along the Missouri River Basin: A time series approach</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Pegg, M.A.; Pierce, C.L.; Roy, A.</p> <p>2003-01-01</p> <p>Human alteration of large rivers is common-place, often resulting in significant changes in flow characteristics. We used a time series approach to examine daily mean flow data from locations throughout the main-stem Missouri River. Data from a pre-alteration period (1925-1948) were compared with a post-alteration period (1967-1996), with separate analyses conducted using either data from the entire year or restricted to the spring fish spawning period (1 April-30 June). Daily mean flows were significantly higher during the post-alteration period at all locations. Flow variability was markedly reduced during the post-alteration period as a probable result of flow regulation and climatological shifts. Daily mean flow during the spring fish spawning period was significantly lower during the post-alteration period at the most highly altered locations in the middle portion of the river, but unchanged at the least altered locations in the upper and lower portions of the river. Our data also corroborate other analyses, using alternate statistical approaches, that suggest similar changes to the Missouri River system. Our results suggest human alterations on the Missouri River, particularly in the middle portion most strongly affected by impoundments and channelization, have resulted in changes to the natural flow regime.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sim/3390/sim3390.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sim/3390/sim3390.pdf"><span>Streamflow distribution maps for the Cannon River drainage basin, southeast Minnesota, and the St. Louis River drainage basin, northeast Minnesota</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Smith, Erik A.; Sanocki, Chris A.; Lorenz, David L.; Jacobsen, Katrin E.</p> <p>2017-12-27</p> <p>Streamflow distribution maps for the Cannon River and St. Louis River drainage basins were developed by the U.S. Geological Survey, in cooperation with the Legislative-Citizen Commission on Minnesota Resources, to illustrate relative and cumulative streamflow distributions. The Cannon River was selected to provide baseline data to assess the effects of potential surficial sand mining, and the St. Louis River was selected to determine the effects of ongoing Mesabi Iron Range mining. Each drainage basin (Cannon, St. Louis) was subdivided into nested drainage basins: the Cannon River was subdivided into 152 nested drainage basins, and the St. Louis River was subdivided into 353 nested drainage basins. For each smaller drainage basin, the estimated volumes of groundwater discharge (as base flow) and surface runoff flowing into all surface-water features were displayed under the following conditions: (1) extreme low-flow conditions, comparable to an exceedance-probability quantile of 0.95; (2) low-flow conditions, comparable to an exceedance-probability quantile of 0.90; (3) a median condition, comparable to an exceedance-probability quantile of 0.50; and (4) a high-flow condition, comparable to an exceedance-probability quantile of 0.02.Streamflow distribution maps were developed using flow-duration curve exceedance-probability quantiles in conjunction with Soil-Water-Balance model outputs; both the flow-duration curve and Soil-Water-Balance models were built upon previously published U.S. Geological Survey reports. The selected streamflow distribution maps provide a proactive water management tool for State cooperators by illustrating flow rates during a range of hydraulic conditions. Furthermore, after the nested drainage basins are highlighted in terms of surface-water flows, the streamflows can be evaluated in the context of meeting specific ecological flows under different flow regimes and potentially assist with decisions regarding groundwater and surface-water appropriations. Presented streamflow distribution maps are foundational work intended to support the development of additional streamflow distribution maps that include statistical constraints on the selected flow conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2009/5257/pdf/sir20095257.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2009/5257/pdf/sir20095257.pdf"><span>Geomorphology and river dynamics of the lower Copper River, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brabets, Timothy P.; Conaway, Jeffrey S.</p> <p>2009-01-01</p> <p>Located in south-central Alaska, the Copper River drains an area of more than 24,000 square miles. The average annual flow of the river near its mouth is 63,600 cubic feet per second, but is highly variable between winter and summer. In the winter, flow averages approximately 11,700 cubic feet per second, and in the summer, due to snowmelt, rainfall, and glacial melt, flow averages approximately 113,000 cubic feet per second, an order of magnitude higher. About 15 miles upstream of its mouth, the Copper River flows past the face of Childs Glacier and enters a large, broad, delta. The Copper River Highway traverses this flood plain, and in 2008, 11 bridges were located along this section of the highway. The bridges cross several parts of the Copper River and in recent years, the changing course of the river has seriously damaged some of the bridges.Analysis of aerial photography from 1991, 1996, 2002, 2006, and 2007 indicates the eastward migration of a channel of the Copper River that has resulted in damage to the Copper River Highway near Mile 43.5. Migration of another channel in the flood plain has resulted in damage to the approach of Bridge 339. As a verification of channel change, flow measurements were made at bridges along the Copper River Highway in 2005–07. Analysis of the flow measurements indicate that the total flow of the Copper River has shifted from approximately 50 percent passing through the bridges at Mile 27, near the western edge of the flood plain, and 50 percent passing through the bridges at Mile 36–37 to approximately 5 percent passing through the bridges at Mile 27 and 95 percent through the bridges at Mile 36–37 during average flow periods.The U.S. Geological Survey’s Multi-Dimensional Surface-Water Modeling System was used to simulate water-surface elevation and velocity, and to compute bed shear stress at two areas where the Copper River is affecting the Copper River Highway. After calibration, the model was used to examine the effects that betterments, such as guide banks or bridge extensions, would have on flow conditions and to provide sound conceptual information that could help decide if a proposed betterment will work or determine potential problems that need to be addressed for a particular betterment. The ability of the model to simulate these hydraulic conditions was constrained by the accuracy and level of channel geometry detail, which is constantly changing in the lower Copper River.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Geomo.227...60B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Geomo.227...60B"><span>Controls on morphological variability and role of stream power distribution pattern, Yamuna River, western India</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bawa, Nupur; Jain, Vikrant; Shekhar, Shashank; Kumar, Niraj; Jyani, Vikas</p> <p>2014-12-01</p> <p>Understanding the controls on the morphological variability of river systems constitutes one of the fundamental questions in geomorphic investigation. Channel morphology is an important indicator of river processes and is of significance for mapping the hydrology-ecologic connectivity in a river system and for predicting the future trajectory of river health in response to external forcings. This paper documents the spatial morphological variability and its natural and anthropogenic controls for the Yamuna River, a major tributary of the Ganga River, India. The Yamuna River runs through a major urban centre i.e. Delhi National Capital Region. The Yamuna River was divided into eight geomorphically distinct reaches on the basis of the assemblages of geomorphic units and the association of landscape, valley and floodplain settings. The morphological variability was analysed through stream power distribution and sediment load data at various stations. Stream power distribution of the Yamuna River basin is characterised by a non-linear pattern that was used to distinguish (a) high energy ‘natural' upstream reaches, (b) ‘anthropogenically altered', low energy middle stream reaches, and (c) ‘rejuvenated' downstream reaches again with higher stream power. The relationship between stream power and channel morphology in these reaches was integrated with sediment load data to define the maximum flow efficiency (MFE) as the threshold for geomorphic transition. This analysis supports the continuity of river processes and the significance of a holistic, basin-scale approach rather than isolated local scale analysis in river studies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70022742','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70022742"><span>Effects of pool formation and flash flooding on relative abundance of young-of-year flannelmouth suckers in the Paria River, Arizona</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Thieme, Michele L.; McIvor, Carole; Brouder, Mark J.; Hoffnagle, Timothy L.</p> <p>2001-01-01</p> <p>Flannelmouth sucker, Catostomus latipinnis, a fish endemic to the Colorado River basin in the western United States, appears to experience poor recruitment to adult size in the Colorado River, downstream of Glen Canyon Dam. Lack or impermanence of rearing areas for young-of-year (YOY) fish is hypothesized to be the problem. Knowing the importance of tributary mouths as rearing areas in other river systems, we studied use of the mouth of the Paria River, a tributary of the Colorado River, by YOY flannelmouth suckers, and the availability of rearing area in the mouth at different flow levels in the Colorado River in 1996 and 1997. We also examined the relationship between flash floods in the Paria River and catch-per-unit-effort (CPUE) of YOY in the Paria River between 1991 and 1996.Maximum mean daily discharge in the Paria River was inversely correlated with CPUE of YOY flannelmouth suckers (Spearman Rho=−0.9856, p=0.0003) during their critical rearing period (15 March–30 June). Thus, it appears that YOY flannelmouth suckers rear longer in the Paria River in years when flash flooding is minimal.Recruitment of YOY flannelmouth suckers at the Paria River may also be improved by enhancing pool formation during spring and summer rearing seasons. YOY flannelmouth sucker was captured in a pool created by high Colorado River flows (≥336 m3/s) that inundated the mouth of the Paria River during spring and summer, 1996. In 1997, high flows (about 550–750 m3/s) in the Colorado River during winter and spring initially inundated the Paria River and formed a pool in the mouth. However, these high flows eventually caused 0.5–1.0 m of suspended sediment from the incoming Paria River to deposit in the mouth. Thus, despite higher flows than 1996, the slackwater area formed only occasionally in 1997. Differences in pool formation between 1996 and 1997 demonstrate that pool formation cannot be inferred solely from Colorado River flows. </p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29074240','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29074240"><span>Biomonitoring of intermittent rivers and ephemeral streams in Europe: Current practice and priorities to enhance ecological status assessments.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stubbington, Rachel; Chadd, Richard; Cid, Núria; Csabai, Zoltán; Miliša, Marko; Morais, Manuela; Munné, Antoni; Pařil, Petr; Pešić, Vladimir; Tziortzis, Iakovos; Verdonschot, Ralf C M; Datry, Thibault</p> <p>2018-03-15</p> <p>Intermittent rivers and ephemeral streams (IRES) are common across Europe and dominate some Mediterranean river networks. In all climate zones, IRES support high biodiversity and provide ecosystem services. As dynamic ecosystems that transition between flowing, pool, and dry states, IRES are typically poorly represented in biomonitoring programmes implemented to characterize EU Water Framework Directive ecological status. We report the results of a survey completed by representatives from 20 European countries to identify current challenges to IRES status assessment, examples of best practice, and priorities for future research. We identify five major barriers to effective ecological status classification in IRES: 1. the exclusion of IRES from Water Framework Directive biomonitoring based on their small catchment size; 2. the lack of river typologies that distinguish between contrasting IRES; 3. difficulties in defining the 'reference conditions' that represent unimpacted dynamic ecosystems; 4. classification of IRES ecological status based on lotic communities sampled using methods developed for perennial rivers; and 5. a reliance on taxonomic characterization of local communities. Despite these challenges, we recognize examples of innovative practice that can inform modification of current biomonitoring activity to promote effective IRES status classification. Priorities for future research include reconceptualization of the reference condition approach to accommodate spatiotemporal fluctuations in community composition, and modification of indices of ecosystem health to recognize both taxon-specific sensitivities to intermittence and dispersal abilities, within a landscape context. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.water.usgs.gov/ofr01-410+','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/ofr01-410+"><span>Location and description of transects for ecological studies in floodplain forests of the lower Suwannee River, Florida</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lewis, L.J.; Light, H.M.; Darst, M.R.</p> <p>2001-01-01</p> <p>Twelve transects were established in floodplain forests along the lower Suwannee River, Florida, as the principal data collection sites for a comprehensive study conducted by the U.S. Geological Survey and the Suwannee River Water Management District from 1996 to 2001. Data collected along the 12 transects included hydrologic conditions, land-surface elevations, soils, and vegetation of floodplain forests in relation to river flow. Transect locations are marked in the field with permanent markers at approximately 30 meter intervals. Detailed descriptions of the 12 transects and their locations are provided so that they can be used for future ecological studies. Descriptions of the transects include contact information necessary for access to the property on which the transects are located, maps showing transect locations and routes from the nearest city or major road, small scale maps of each transect showing marker locations, latitude and longitude of each marker, compass bearings of each transect line and graphs showing land-surface elevations of the transect with marker locations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007HESS...11.1175K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007HESS...11.1175K"><span>Hydrological impacts of climate change on the Tejo and Guadiana Rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kilsby, C. G.; Tellier, S. S.; Fowler, H. J.; Howels, T. R.</p> <p>2007-05-01</p> <p>A distributed daily rainfall runoff model is applied to the Tejo and Guadiana river basins in Spain and Portugal to simulate the effects of climate change on runoff production, river flows and water resource availability with results aggregated to the monthly level. The model is calibrated, validated and then used for a series of climate change impact assessments for the period 2070 2100. Future scenarios are derived from the HadRM3H regional climate model (RCM) using two techniques: firstly a bias-corrected RCM output, with monthly mean correction factors calculated from observed rainfall records; and, secondly, a circulation-pattern-based stochastic rainfall model. Major reductions in rainfall and streamflow are projected throughout the year; these results differ from those for previous studies where winter increases are projected. Despite uncertainties in the representation of heavily managed river systems, the projected impacts are serious and pose major threats to the maintenance of bipartite water treaties between Spain and Portugal and the supply of water to urban and rural regions of Portugal.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018EnMan..61..421H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018EnMan..61..421H"><span>Compounding Effects of Agricultural Land Use and Water Use in Free-Flowing Rivers: Confounding Issues for Environmental Flows</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hardie, Scott A.; Bobbi, Chris J.</p> <p>2018-03-01</p> <p>Defining the ecological impacts of water extraction from free-flowing river systems in altered landscapes is challenging as multiple stressors (e.g., flow regime alteration, increased sedimentation) may have simultaneous effects and attributing causality is problematic. This multiple-stressor context has been acknowledged in environmental flows science, but is often neglected when it comes to examining flow-ecology relationships, and setting and implementing environmental flows. We examined the impacts of land and water use on rivers in the upper Ringarooma River catchment in Tasmania (south-east Australia), which contains intensively irrigated agriculture, to support implementation of a water management plan. Temporal and spatial and trends in river condition were assessed using benthic macroinvertebrates as bioindicators. Relationships between macroinvertebrate community structure and environmental variables were examined using univariate and multivariate analyses, focusing on the impacts of agricultural land use and water use. Structural changes in macroinvertebrate communities in rivers in the catchment indicated temporal and spatial declines in the ecological condition of some stretches of river associated with agricultural land and water use. Moreover, water extraction appeared to exacerbate impairment associated with agricultural land use (e.g., reduced macroinvertebrate density, more flow-avoiding taxa). The findings of our catchment-specific bioassessments will underpin decision-making during the implementation of the Ringarooma water management plan, and highlight the need to consider compounding impacts of land and water use in environmental flows and water planning in agricultural landscapes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28258469','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28258469"><span>Compounding Effects of Agricultural Land Use and Water Use in Free-Flowing Rivers: Confounding Issues for Environmental Flows.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hardie, Scott A; Bobbi, Chris J</p> <p>2018-03-01</p> <p>Defining the ecological impacts of water extraction from free-flowing river systems in altered landscapes is challenging as multiple stressors (e.g., flow regime alteration, increased sedimentation) may have simultaneous effects and attributing causality is problematic. This multiple-stressor context has been acknowledged in environmental flows science, but is often neglected when it comes to examining flow-ecology relationships, and setting and implementing environmental flows. We examined the impacts of land and water use on rivers in the upper Ringarooma River catchment in Tasmania (south-east Australia), which contains intensively irrigated agriculture, to support implementation of a water management plan. Temporal and spatial and trends in river condition were assessed using benthic macroinvertebrates as bioindicators. Relationships between macroinvertebrate community structure and environmental variables were examined using univariate and multivariate analyses, focusing on the impacts of agricultural land use and water use. Structural changes in macroinvertebrate communities in rivers in the catchment indicated temporal and spatial declines in the ecological condition of some stretches of river associated with agricultural land and water use. Moreover, water extraction appeared to exacerbate impairment associated with agricultural land use (e.g., reduced macroinvertebrate density, more flow-avoiding taxa). The findings of our catchment-specific bioassessments will underpin decision-making during the implementation of the Ringarooma water management plan, and highlight the need to consider compounding impacts of land and water use in environmental flows and water planning in agricultural landscapes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2008/1113/pdf/OFR-2008-1113.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2008/1113/pdf/OFR-2008-1113.pdf"><span>Analysis of Pulsed Flow Modification Alternatives, Lower Missouri River, 2005</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jacobson, Robert B.</p> <p>2008-01-01</p> <p>The graphical, tabular, and statistical data presented in this report resulted from analysis of alternative flow regime designs considered by a group of Missouri River managers, stakeholders, and scientists during the summer of 2005. This plenary group was charged with designing a flow regime with increased spring flow pulses to support reproduction and survival of the endangered pallid sturgeon. Environmental flow components extracted from the reference natural flow regime were used to design and assess performance of alternative flow regimes. The analysis is based on modeled flow releases from Gavins Point Dam (near Yankton, South Dakota) for nine design alternatives and two reference scenarios; the reference scenarios are the run-of-the-river and the water-control plan implemented in 2004. The alternative designs were developed by the plenary group with the goal of providing pulsed spring flows, while retaining traditional social and economic uses of the river.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70009716','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70009716"><span>Dual-RiverSonde measurements of two-dimensional river flow patterns</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Teague, C.C.; Barrick, D.E.; Lilleboe, P.M.; Cheng, R.T.; Stumpner, P.; Burau, J.R.</p> <p>2008-01-01</p> <p>Two-dimensional river flow patterns have been measured using a pair of RiverSondes in two experiments in the Sacramento-San Joaquin River Delta system of central California during April and October 2007. An experiment was conducted at Walnut Grove, California in order to explore the use of dual RiverSondes to measure flow patterns at a location which is important in the study of juvenile fish migration. The data available during the first experiment were limited by low wind, so a second experiment was conducted at Threemile Slough where wind conditions and surface turbulence historically have resulted in abundant data. Both experiments included ADCP near-surface velocity measurements from either manned or unmanned boats. Both experiments showed good comparisons between the RiverSonde and ADCP measurements. The flow conditions at both locations are dominated by tidal effects, with partial flow reversal at Walnut Grove and complete flow reversal at Threemile Slough. Both systems showed complex flow patterns during the flow reversals. Quantitative comparisons between the RiverSondes and an ADCP on a manned boat at Walnut Grove showed mean differences of 4.5 cm/s in the u (eastward) and 7.6 cm/s in the v (northward) components, and RMS differences of 14.7 cm/s in the u component and 21.0 cm/s in the v component. Quantitative comparisons between the RiverSondes and ADCPs on autonomous survey vessels at Threemile Slough showed mean differences of 0.007 cm/s in the u component and 0.5 cm/s in the v component, and RMS differences of 7.9 cm/s in the u component and 13.5 cm/s in the v component after obvious outliers were removed. ?? 2008 IEEE.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70022454','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70022454"><span>Role of lake regulation on glacier fed rivers in enhancing salmon productivity: The Cook Inlet watershed south central Alaska, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hupp, C.R.</p> <p>2000-01-01</p> <p>Rivers fed by glaciers constitute a major part of the freshwater runoff into the Cook Inlet basin of south-central Alaska. This basin is very important to the economy of the State of Alaska because it is home to more than half of the population and it supports multi-million dollar commercial, subsistence and sport fisheries. Hence an understanding of how glacial runoff influences biological productivity is important for managing rivers that drain into Cook Inlet. This paper examines the ways in which the regulation of glacier-fed rivers by proglacial lakes affects salmon productivity, with particular reference to the Kenai River. Salmon escapement per unit channel length on the Kenai River is between two and ten times that found for rain-and-snowmelt dominated rivers and glacier-fed rivers lacking lake regulation. Lakes are shown to influence biological processes in glacier-fed rivers by attenuating peak flows, sustaining high flows throughout the summer, supplementing winter low flows, settling suspended sediment, and increasing river temperatures. Downstream from large lakes, glacier-fed rivers are less disturbed, channels are relatively stable and have well-developed salmonid habitats. The positive influences are indicated by the high diversity and abundances of benthic macroinvertebrates, which are important food resources for juvenile salmonids. High summer flows allow access for up-river salmon runs and lakes also provide both overwintering and rearing habitat. Copyright ?? 2000 John Wiley & Sons, Ltd.Rivers fed by glaciers constitute a major part of the freshwater runoff into the Cook Inlet basin of south-central Alaska. This basin is very important to the economy of the State of Alaska because it is home to more than half of the population and it supports multi-million dollar commercial, subsistence and sport fisheries. Hence an understanding of how glacial runoff influences biological productivity is important for managing rivers that drain into Cook Inlet. This paper examines the ways in which the regulation of glacier-fed rivers by proglacial lakes affects salmon productivity, with particular reference to the Kenai River. Salmon escapement per unit channel length on the Kenai River is between two and ten times that found for rain-and-snowmelt dominated rivers and glacier-fed rivers lacking lake regulation. Lakes are shown to influence biological processes in glacier-fed rivers by attenuating peak flows, sustaining high flows throughout the summer, supplementing winter low flows, settling suspended sediment, and increasing river temperatures. Downstream from large lakes, glacier-fed rivers are less disturbed, channels are relatively stable and have well-developed salmonid habitats. The positive influences are indicated by the high diversity and abundances of benthic macroinvertebrates, which are important food resources for juvenile salmonids. High summer flows allow access for up-river salmon runs and lakes also provide both overwintering and rearing habitat.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title33-vol3/pdf/CFR-2010-title33-vol3-sec207-350.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title33-vol3/pdf/CFR-2010-title33-vol3-sec207-350.pdf"><span>33 CFR 207.350 - St. Croix River, Wis. and Minn.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>..., the full natural run of water in the river shall be permitted to flow between 1 a.m. on Thursday and 4... shall have the right to sluice, drive, and float loose logs and to regulate the flow of water in the... river flow exceeds 1,600 feet per second, the reduced flow shall be not less than 1,600 feet per second...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.5941W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.5941W"><span>Risk analysis for the flood control capacity of dikes under climate change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wei, Hsiao Ping; Yeh, Keh-Chia; Hsiao, Yi-Hua</p> <p>2017-04-01</p> <p>Climate change is the major reason for many extreme disaster events. In recent years, scientists have revealed many findings and most of them agree that the frequency of extreme weather and its corresponding hydrological impact will increase due to climate change. In such situation, the current hydrologic designs based upon historical observation, which could be changed, are necessary to review again under the scenario of climate change. It is for this reason that this study uses Kao-Ping River Basin as an example, using high resolution dynamical downscaling data (base period, near future, and end of the century) to simulate changes in hourly flow rate of typhoon events in each of the three 25-year periods. Results are further compared with the design flow rate announced by the competent authority of water resources, as well as recorded river water levels of the most severe typhoon event in history and risk analysis basic on factors, to evaluate the risk and impact of river flooding under climate change.From the simulation results, the frequency of exceeding design discharge in Kao-ping river catchment will increase in the end of century. The water level at these LI-LIN BRIDGE and SAN-TI-MEN gauges could be obviously influenced due to the extreme rainfall events, so that their flood control capacity should be assessed and improved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H13A1316L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H13A1316L"><span>Influence of the South-to-North Water Transfer and the Yangtze River Mitigation Projects on the water quality of Han River, China</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, W.; Kuo, Y. M.</p> <p>2016-12-01</p> <p>The Middle Route of China's South-to-North Water Transfer (MSNW) and Yangtze-Han River Water Diversion (YHWD) Projects have been operated since 2014, which may deteriorate water quality in Han River. The 11 water sampling sites distributed from the middle and down streams of Han River watershed were monitored monthly between July 2014 and December 2015. Factor analysis and cluster analysis were applied to investigate the major pollution types and main variables influencing water quality in Han River. The factor analysis distinguishes three main pollution types (agricultural nonpoint source, organic, and phosphorus point source pollution) affecting water quality of Han River. Cluster analysis classified all sampling sites into four groups and determined their pollution source for both Dry and Wet seasons. The sites located at central city receive point source pollution in both seasons. The water quality in downstream Han River (excluding central city sites) was influenced by nonpoint source pollution from Jianghan Plain. Variations of water qualities are associated with hydrological conditions varied from operations of engineering projects and seasonal variability especially in Dry season. Good water quality as Class III mainly occurred when flow rate is greater than 800 cms in Dry season. The low average flow rate below 583 cms will degrade water quality as Class V at almost all sites. Elevating the flow rate discharged from MSNW and YHWD Projects to Han River can avoid degrading water quality especially in low flow conditions and may decrease the probability of algal bloom occurrence in Han River. Increasing the flow rate from 400 cms to 700 cms in main Han River can obviously improve the water quality of Han River. The investigation of relationships between water quality and flow rate in both projects can provide management strategies of water quality for various flow conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940038873&hterms=atmospheric+rivers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Datmospheric%2Brivers','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940038873&hterms=atmospheric+rivers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Datmospheric%2Brivers"><span>Continental-scale river flow in climate models</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miller, James R.; Russell, Gary L.; Caliri, Guilherme</p> <p>1994-01-01</p> <p>The hydrologic cycle is a major part of the global climate system. There is an atmospheric flux of water from the ocean surface to the continents. The cycle is closed by return flow in rivers. In this paper a river routing model is developed to use with grid box climate models for the whole earth. The routing model needs an algorithm for the river mass flow and a river direction file, which has been compiled for 4 deg x 5 deg and 2 deg x 2.5 deg resolutions. River basins are defined by the direction files. The river flow leaving each grid box depends on river and lake mass, downstream distance, and an effective flow speed that depends on topography. As input the routing model uses monthly land source runoff from a 5-yr simulation of the NASA/GISS atmospheric climate model (Hansen et al.). The land source runoff from the 4 deg x 5 deg resolution model is quartered onto a 2 deg x 2.5 deg grid, and the effect of grid resolution is examined. Monthly flow at the mouth of the world's major rivers is compared with observations, and a global error function for river flow is used to evaluate the routing model and its sensitivity to physical parameters. Three basinwide parameters are introduced: the river length weighted by source runoff, the turnover rate, and the basinwide speed. Although the values of these parameters depend on the resolution at which the rivers are defined, the values should converge as the grid resolution becomes finer. When the routing scheme described here is coupled with a climate model's source runoff, it provides the basis for closing the hydrologic cycle in coupled atmosphere-ocean models by realistically allowing water to return to the ocean at the correct location and with the proper magnitude and timing.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013Geomo.185...27H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013Geomo.185...27H"><span>An assessment of the suspended sediment rating curve approach for load estimation on the Rivers Bandon and Owenabue, Ireland</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harrington, Seán T.; Harrington, Joseph R.</p> <p>2013-03-01</p> <p>This paper presents an assessment of the suspended sediment rating curve approach for load estimation on the Rivers Bandon and Owenabue in Ireland. The rivers, located in the South of Ireland, are underlain by sandstone, limestones and mudstones, and the catchments are primarily agricultural. A comprehensive database of suspended sediment data is not available for rivers in Ireland. For such situations, it is common to estimate suspended sediment concentrations from the flow rate using the suspended sediment rating curve approach. These rating curves are most commonly constructed by applying linear regression to the logarithms of flow and suspended sediment concentration or by applying a power curve to normal data. Both methods are assessed in this paper for the Rivers Bandon and Owenabue. Turbidity-based suspended sediment loads are presented for each river based on continuous (15 min) flow data and the use of turbidity as a surrogate for suspended sediment concentration is investigated. A database of paired flow rate and suspended sediment concentration values, collected between the years 2004 and 2011, is used to generate rating curves for each river. From these, suspended sediment load estimates using the rating curve approach are estimated and compared to the turbidity based loads for each river. Loads are also estimated using stage and seasonally separated rating curves and daily flow data, for comparison purposes. The most accurate load estimate on the River Bandon is found using a stage separated power curve, while the most accurate load estimate on the River Owenabue is found using a general power curve. Maximum full monthly errors of - 76% to + 63% are found on the River Bandon with errors of - 65% to + 359% found on the River Owenabue. The average monthly error on the River Bandon is - 12% with an average error of + 87% on the River Owenabue. The use of daily flow data in the load estimation process does not result in a significant loss of accuracy on either river. Historic load estimates (with a 95% confidence interval) were hindcast from the flow record and average annual loads of 7253 ± 673 tonnes on the River Bandon and 1935 ± 325 tonnes on the River Owenabue were estimated to be passing the gauging stations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/806232','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/806232"><span>Emigration of Natural and Hatchery Chinook Salmon and Steelhead Smolts from the Imnaha River, Oregon, 1998-1999 Annual Report.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Cleary, Peter J.; Blenden, Michael L.; Kucera, Paul A.</p> <p>2002-08-01</p> <p>This report summarizes the results of the Lower Snake River Compensation Plan Hatchery Evaluation Studies (LSRCP) and the Imnaha Smolt Monitoring Program (SMP) for the 1999 smolt migration from the Imnaha River, Oregon. These studies were designed and closely coordinated to provide information about juvenile natural and hatchery chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss) biological characteristics, behavior and emigrant timing, survival, arrival timing and travel time to the Snake River dams and McNary Dam on the Columbia River. Data collected from these studies are shared with the Fish Passage Center (FPC). These data are essential to quantify smoltmore » survival rates under the current passage conditions and to evaluate the future recovery strategies that seek to optimize smolt survival through the hydroelectric system. Information shared with the FPC assists with in-season shaping of flow and spill management requests in the Snake River reservoirs. The Bonneville Power Administration and the United States Fish and Wildlife Service contracted the Nez Perce Tribe (NPT) to monitor emigration timing and tag 21,200 emigrating natural and hatchery chinook salmon and steelhead smolts from the Imnaha River during the spring emigration period (March 1-June 15) with passive integrated transponder (PIT) tags. The completion of trapping in the spring of 1999 marked the eighth year of emigration studies on the Imnaha River and the sixth year of participating in the FPC smolt monitoring program. Monitoring and evaluation objectives were to: (1) Determine spring emigration timing of chinook salmon and steelhead smolts collected at the Imnaha River trap. (2) Evaluate effects of flow, temperature and other environmental factors on emigration timing. (3) Monitor the daily catch and biological characteristics of juvenile chinook salmon and steelhead smolts collected at the Imnaha River screw trap. (4) Determine emigration timing, travel time, and in-river survival of PIT tagged hatchery chinook salmon smolts released at the Imnaha River acclimation facility to the Imnaha River Trap. (5) Determine arrival timing, travel time and estimated survival of PIT tagged hatchery and natural chinook salmon and natural and hatchery steelhead smolts from the Imnaha River to Snake and Columbia river dams.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2011/5091/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2011/5091/"><span>Estimation of annual suspended-sediment fluxes, 1931-95, and evaluation of geomorphic changes, 1950-2010, in the Arkansas River near Tulsa, Oklahoma</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lewis, Jason M.; Smith, S. Jerrod; Buck, Stephanie D.; Strong, Scott A.</p> <p>2011-01-01</p> <p>An understanding of fluvial sediment transport and changing channel morphology can assist planners in making responsible decisions with future riverine development or restoration projects. Sediment rating curves can serve as simple models and can provide predictive tools to estimate annual sediment fluxes. Sediment flux models can aid in the design of river projects by providing insight to past and potential future sediment fluxes. Historical U.S. Geological Survey suspended-sediment and discharge data were evaluated to estimate annual suspended-sediment fluxes for two stations on the Arkansas River located downstream from Keystone Dam in Tulsa County. Annual suspended-sediment fluxes were estimated from 1931-95 for the Arkansas River at Tulsa streamflow-gaging station (07164500) and from 1973-82 for the Arkansas River near Haskell streamflow-gaging station (07165570). The annual flow-weighted suspended-sediment concentration decreased from 1,970 milligrams per liter to 350 milligrams per liter after the completion of Keystone Dam at the Tulsa station. The streambed elevation at the Arkansas River at Tulsa station has changed less than 1 foot from 1970 to 2005, but the thalweg has shifted from a location near the right bank to a position near the left bank. There was little change in the position of most of the banks of the Arkansas River channel from 1950 to 2009. The most substantial change evident from visual inspection of aerial photographs was an apparent decrease in sediment storage in the form of mid-channel and meander bars. The Arkansas River channel between Keystone Dam and the Tulsa-Wagoner County line showed a narrowing and lengthening (increase in sinuosity) over the transition period 1950-77 followed by a steady widening and shortening of the river channel (decrease in sinuosity) during the post-dam (Keystone) periods 1977-85, 1985-2003, and 2003-10.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70028516','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70028516"><span>Longitudinal hydraulic analysis of river‐aquifer exchanges</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Konrad, C.P.</p> <p>2006-01-01</p> <p>A longitudinal analysis of transient flow between a river and an underlying aquifer is developed to calculate flow rates between the river and the aquifer and the location of groundwater seepage into the river as it changes over time. Two flow domains are defined in the analysis: an upstream domain of fluvial recharge, where water flows vertically from the river into the unsaturated portion of the aquifer and horizontally in saturated parts of the aquifer, and a downstream domain of groundwater seepage to the river, where groundwater flows parallel to the underlying impermeable base. The river does not necessarily penetrate completely through the aquifer. A one‐dimensional, unsteady flow equation is derived from mass conservation, Darcy's law, and the geometry of the river‐aquifer system to calculate the water table position and the groundwater seepage rate into the river. Models based on numerical and analytical solutions of the flow equation were applied to a reach of the Methow River in north central Washington. The calibrated models simulated groundwater seepage with a root‐mean‐square error less than 5% of the mean groundwater seepage rates for three low‐flow evaluation periods. The analytical model provides a theoretical basis for a nonlinear exponential base flow recession generated by a draining aquifer, but not an explicit functional form for the recession. Unlike cross‐sectional approaches, the longitudinal approach allows the analysis of the length and location of groundwater seepage to a river, which have important ecological implications in many rivers. In the numerical simulations, the length of the groundwater seepage varied seasonally by about 4 km and the upstream boundary of groundwater seepage was within 689 m of its location at a stream gage on 9 September 2001 and within 91 m of its location on 6 October 2002. To demonstrate its utility in ecological applications, the numerical model was used to calculate differences in length of groundwater seepage to the Methow River under an early runoff scenario and the timing of those differences with respect to life stages of chinook salmon.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=61922&Lab=NHEERL&keyword=oceanography&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=61922&Lab=NHEERL&keyword=oceanography&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>AN ECOSYSTEM MODEL OF A RIVER-DOMINATED PACIFIC NORTHWEST ESTUARY: ROLES OF SALT MARSH-, RIVER- AND OCEAN-DERIVED MATERIALS</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The Salmon River estuary on the central Oregon coast is river-dominated, with hydraulic residence times ranging from <1 day during winter high flows to a week during low flows. The estuary receives organic matter and nutrients from the river, the coastal ocean, and a bordering s...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=61153&keyword=nursery&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=61153&keyword=nursery&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>AN ECOSYSTEM MODEL OF A RIVER-DOMINATED PACIFIC NORTHWEST ESTURARY: ROLES OF SALT MARSH-, RIVER-, AND OCEAN-DERIVED MATERIALS</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The Salmon River estuary on the central Oregon coast is river-dominated, with hydraulic residence times ranging from <1 day during winter high flows to a week during low flows. The estuary receives organic matter and nutrients from the river, the coastal ocean, and a bordering s...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70154886','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70154886"><span>Natural flow regimes of the Ozark-Ouachita Interior Highlands region</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Leasure, D. R.; Magoulick, Daniel D.; Longing, S. D.</p> <p>2016-01-01</p> <p>Natural flow regimes represent the hydrologic conditions to which native aquatic organisms are best adapted. We completed a regional river classification and quantitative descriptions of each natural flow regime for the Ozark–Ouachita Interior Highlands region of Arkansas, Missouri and Oklahoma. On the basis of daily flow records from 64 reference streams, seven natural flow regimes were identified with mixture model cluster analysis: Groundwater Stable, Groundwater, Groundwater Flashy, Perennial Runoff, Runoff Flashy, Intermittent Runoff and Intermittent Flashy. Sets of flow metrics were selected that best quantified nine ecologically important components of these natural flow regimes. An uncertainty analysis was performed to avoid selecting metrics strongly affected by measurement uncertainty that can result from short periods of record. Measurement uncertainties (bias, precision and accuracy) were assessed for 170 commonly used flow metrics. The ranges of variability expected for select flow metrics under natural conditions were quantified for each flow regime to provide a reference for future assessments of hydrologic alteration. A random forest model was used to predict the natural flow regimes of all stream segments in the study area based on climate and catchment characteristics, and a map was produced. The geographic distribution of flow regimes suggested distinct ecohydrological regions that may be useful for conservation planning. This project provides a hydrologic foundation for future examination of flow–ecology relationships in the region. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26627697','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26627697"><span>The concentration and chemical speciation of arsenic in the Nanpan River, the upstream of the Pearl River, China.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Silin; Zhao, Ning; Zhou, Dequn; Wei, Rong; Yang, Bin; Pan, Bo</p> <p>2016-04-01</p> <p>The concentration and chemical speciation of arsenic (As) in different environmental matrixes (water, sediment, agricultural soils, and non-agricultural soils) were investigated in the Nanpan River area, the upstream of Pearl River, China. The results did not show any obvious transport of As along the flow direction of the river (from upstream to downstream). Total As concentrations in sediment were significantly different from those in agricultural soil. According to the comparison to quality standards, the As in sediments of the studied area have potential ecological risks and a minority of the sampling sites of agricultural soils in the studied area were polluted with As. As speciations were analyzed using sequential extraction and the percentage of non-residual fraction in sediment predominated over residual fraction. We thus believe that As in the studied area was with low mobility and bioavailability in sediment, agricultural soils, and non-agricultural soils. However, the bioavailability and mobility of As in sediment were higher than in both agricultural and non-agricultural soils, and thus, special attention should be paid for the risk assessment of As in the river in future studies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1810404C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1810404C"><span>The Devdorak ice-rock avalanche and consequent debris flow from the slope of Mt. Kazbek (Caucasus, Georgia) in 2014</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chernomorets, Sergey; Savernyuk, Elena; Petrakov, Dmitry; Dokukin, Mikhail; Gotsiridze, George; Gavardashvili, Givi; Drobyshev, Valery; Tutubalina, Olga; Zaporozhchenko, Eduard; Kamenev, Nikolay; Kamenev, Vladimir; Kääb, Andreas; Kargel, Jeffrey; Huggel, Christian</p> <p>2016-04-01</p> <p>We have studied catastrophic glacial events of 2014 in the Kazbek-Dzhimaray massif, Caucasus Mts., Georgia. The first event is a so called "Kazbek blockage" of the Georgian Military Road, on 17 May 2014, which formed as a result of an ice-rock avalanche onto the Devdorak Glacier, and is similar to blockages which occurred in the same location in the 18th-19th century. The second event is a consequent debris flow on 20 August 2014. In May, June 2014 and September 2015 we conducted three field investigations of the disaster zone, which includes Devdorak Glacier, Amilishka and Kabakhi river valleys, the Terek River valley near the Kabakhi River mouth, and a temporary lake.We analyzed field research data, interpreted SPOT 6, Landsat-8 OLI, Terra ASTER, and Pleiades satellite imagery, as well as post-disaster helicopter imagery. To assess dynamic features of the ice-rock flow on 17 May 2014, we measured valley crossections with Bushnell laser ranger. In 2015 we have marked a 180-m baseline for ground stereosurvey and made a stereopair of the Devdorak glacier terminus from a distance of 700 m. The 17 May 2014 ice-rock avalanche initiated at 4500 m. a.s.l. It collapsed onto the tongue of the Devdorak Glacier which reaches down to 2300 m a.s.l. Downstream of the tongue, the avalanche transformed into an ice-rock "avalanche flow" which blocked the Terek River valley. The traffic on Military Georgian Road (part of E117 highway) which connects Russia with Georgia was stopped. 7 people were killed in their vehicles. The total length of the ice-rock avalanche and the subsequent flow was over 10 km. A temporary lake formed in the Terek river valley, reaching 300 m in length, and over 10 m in depth. For several hours, the lake was threatening another debris flow downstream the Terek river valley. According to field estimates at the Devdorak glacier tongue and in Amilishka, Kabakhi and Terek river valleys, the volume of the transported ice-rock avalanche mass, which deposited in the middle and lower course of the valley below 3000 m a.s.l. was about 2 million cubic metres, while the ice content in the deposits reached 25-30%. It is planned to assess the volume of the trigger mass in the initiation zone later. The flow went along the valley with characteristic superelevations and run-ups, as it moved from one valley side to the other. We identified six superelevaions in fresh deposits, with differences of up to 45 m in flow height on the left and right valley banks. Instrumental measurements of superelevations and subsequent calculations yield the flow velocities of over 200 km/hour. These results lead to a reassessment of similar events which occurred in this valley in 18-19th centuries. Previously the trigger of these events was supposed to be the ice accumulation during surges of Devdorak glacier with subsequent temporary damming of the Amilishka River valley. The analysis of the 2014 event demonstrates that a similar trigger was possible in the past: an ice-rock avalanche onto Devdorak glacier tongue from significantly higher locations. Following the field data analysis, we issued a warning through mass media on 12 August 2014, forecasting a high risk of a new glacial disaster in this site and a new blockage of the Terek River valley and of Military Georgian Road. This forecast came true on 20 August 2014: a glacial debris flow reached the Terek River valley, and partially buried the Dariali hydropower station (under construction), the customs and border control buildings. Three people have been killed. We studied the deposits of this debris flow and morphology of the gully. The deposits entrained by the flow were previously deposited by the ice-rock avalanche of 17 May 2014. The debris flow started after shower rains. The debris flow-gully has a box-like crossection. At the confluence of Amilishka and Chach rivers it reached 30-32 m in width, and eroded the deposits of 17 May 2014 by 7 m. The channel slope at this location was about 7 degrees. Remnant ice in the transit zone has nearly melted by September 2015; however, the ice remains in the deposits near the glacier tongue and in the ice-rock avalanche deposits on the tongue. We have registered the advance of one of the termini of Devdorak Glacier. It moved forward by about 200 m from summer 2014 to September 2015, and became significantly higher. This part of the glacier was overloaded by the ice-rock avalanche deposits which provoked its advance, and should be closely monitored as it can raise the debris flow activity further. The hazard of new ice-rock avalanches and debris flows in the Devdorak gorge remains high. We have developed recommendation on the installation of an early warning system, continuation of glacier hazard monitoring, and suggestions on the construction of a road tunnel to mitigate the risk and avoid casualties in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GPC...158...47F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GPC...158...47F"><span>Analysis of land use and climate change impacts by comparing river flow records for headwaters and lowland reaches</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fazel, Nasim; Torabi Haghighi, Ali; Kløve, Bjørn</p> <p>2017-11-01</p> <p>The natural flow regime of rivers has been strongly altered world-wide, resulting in ecosystem degradation and lakes drying up, especially in arid and semi-arid regions. Determining whether this is due mainly to climate change or to water withdrawal for direct human use (e.g. irrigation) is difficult, particularly for saline lake basins where hydrology data are scarce. In this study, we developed an approach for assessing climate and land use change impacts based on river flow records for headwater and lowland reaches of rivers, using the case of Lake Urmia basin, in north-westen Iran. Flow regimes at upstream and downstream stations were studied before and after major dam construction and irrigation projects. Data from 57 stations were used to establish five different time intervals representing 10 different land use development periods (scenarios) for upstream (not impacted) and downstream (impacted) systems. An existing river impact (RI) index was used to assess changes in three main characteristics of flow (magnitude, timing and, intra-annual variability). The results showed that irrigation was by far the main driving force for river flow regime changes in the lake basin. All stations close to the lake and on adjacent plains showed significantly higher impacts of land use change than headwaters. As headwaters are relatively unaffected by agriculture, the non-significant changes observed in headwater flow regimes indicate a minor effect of climate change on river flows in the region. The benefit of the method developed is clear interpretation of results based on river flow records, which is useful in communicating land use and climate change information to decision makers and lake restoration planners.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PCE....94..106M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PCE....94..106M"><span>Influence of deposition of fine plant debris in river floodplain shrubs on flood flow conditions - The Warta River case study</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mazur, Robert; Kałuża, Tomasz; Chmist, Joanna; Walczak, Natalia; Laks, Ireneusz; Strzeliński, Paweł</p> <p>2016-08-01</p> <p>This paper presents problems caused by organic material transported by flowing water. This material is usually referred to as plant debris or organic debris. Its composition depends on the characteristic of the watercourse. For lowland rivers, the share of the so-called small organic matter in plant debris is considerable. This includes both various parts of water plants and floodplain vegetation (leaves, stems, blades of grass, twigs, etc.). During floods, larger woody debris poses a significant risk to bridges or other water engineering structures. It may cause river jams and may lead to damming of the flowing water. This, in turn, affects flood safety and increases flood risk in river valleys, both directly and indirectly. The importance of fine plant debris for the phenomenon being studied comes down to the hydrodynamic aspect (plant elements carried by water end up on trees and shrubs, increase hydraulic flow resistance and contribute to the nature of flow through vegetated areas changed from micro-to macro-structural). The key part of the research problem under analysis was to determine qualitative and quantitative debris parameters and to establish the relationship between the type of debris and the type of land use of river valleys (crop fields, meadows and forested river sections). Another problem was to identify parameters of plant debris for various flow conditions (e.g. for low, medium and flood flows). The research also included an analysis of the materials deposited on the structure of shrubs under flood flow conditions during the 2010 flood on the Warta River.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70027595','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70027595"><span>Management scenarios for the Jordan River salinity crisis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Farber, E.; Vengosh, A.; Gavrieli, I.; Marie, Amarisa; Bullen, T.D.; Mayer, B.; Holtzman, R.; Segal, M.; Shavit, U.</p> <p>2005-01-01</p> <p>Recent geochemical and hydrological findings show that the water quality of the base flow of the Lower Jordan River, between the Sea of Galilee and the Dead Sea, is dependent upon the ratio between surface water flow and groundwater discharge. Using water quality data, mass-balance calculations, and actual flow-rate measurements, possible management scenarios for the Lower Jordan River and their potential affects on its salinity are investigated. The predicted scenarios reveal that implementation of some elements of the Israel-Jordan peace treaty will have negative effects on the Jordan River water salinity. It is predicted that removal of sewage effluents dumped into the river (???13 MCM/a) will significantly reduce the river water's flow and increase the relative proportion of the saline groundwater flux into the river. Under this scenario, the Cl content of the river at its southern point (Abdalla Bridge) will rise to almost 7000 mg/L during the summer. In contrast, removal of all the saline water (16.5 MCM/a) that is artificially discharged into the Lower Jordan River will significantly reduce its Cl concentration, to levels of 650-2600 and 3000-3500 mg/L in the northern and southern areas of the Lower Jordan River, respectively. However, because the removal of either the sewage effluents or the saline water will decrease the river's discharge to a level that could potentially cause river desiccation during the summer months, other water sources must be allocated to preserve in-stream flow needs and hence the river's ecosystem. ?? 2005 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.2556E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.2556E"><span>Governance and decision making in complex socio-hydrological systems</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elshorbagy, Amin; Wheater, Howard; Gober, Patricia; Hassanzadeh, Elmira</p> <p>2017-04-01</p> <p>The transboundary Saskatchewan River, originating in the Canadian Rockies in Alberta, flows through Saskatchewan and Manitoba and discharges its water into Lake Winnipeg. It supports irrigated agriculture, hydropower generation, flood protection, municipal water supplies, mining, recreation, and environmental services across a large area and in multiple administrative jurisdictions. Managing the region's water-based economic activities and environmental services, requires decisions at a variety of scales to incorporate competing values and priorities about water use. Current inter-provincial allocations are based on the 1969 Master Agreement of Water Apportionment whereby upstream Alberta must release one-half of the annual natural flows of the Saskatchewan River to Saskatchewan, which in turn must pass one-half of the residual natural flow to the Province of Manitoba. This analysis uses a hydro-economic simulation model, SWAMP, to examine risk-based tradeoffs in Saskatchewan for various types of water use including, agriculture, energy, and flood protection under various scenarios of water availability. The eco-hydrological effects of the scenarios on the largest inland delta in North America - the Saskatchewan River Delta - are also shown. Results enable decision makers to weigh the costs and benefits of implementing particular sector-based future development strategies. Assuming net provincial benefit as a single monetary indicator of economic value, the effects of various scenarios of environmental and policy changes are quantified Results show that improving irrigation technology and expanding irrigated lands in Alberta will positively affect the province's economic development and have compound effects downstream on hydropower generation, environmental flows and the economies of Saskatchewan and Manitoba. The implementation of similar policies in Saskatchewan will have different downstream impacts because of the large hydro-power capacity downstream in Manitoba. The model highlights the spatial tradeoffs across the three provinces and sectoral trade-offs among the differing water uses. These trade-offs represent challenging dilemmas for water management decisions in a complex system. The study reveals the need for a holistic framework of water resources analysis that can dynamically capture the feedback loops among hydrological, social, and administrative/political analysis units to support public discussion of critical water tradeoffs and a consensual water value framework to guide future development decisions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1713942S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1713942S"><span>Fish habitat regression under water scarcity scenarios in the Douro River basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Segurado, Pedro; Jauch, Eduardo; Neves, Ramiro; Ferreira, Teresa</p> <p>2015-04-01</p> <p>Climate change will predictably alter hydrological patterns and processes at the catchment scale, with impacts on habitat conditions for fish. The main goals of this study are to identify the stream reaches that will undergo more pronounced flow reduction under different climate change scenarios and to assess which fish species will be more affected by the consequent regression of suitable habitats. The interplay between changes in flow and temperature and the presence of transversal artificial obstacles (dams and weirs) is analysed. The results will contribute to river management and impact mitigation actions under climate change. This study was carried out in the Tâmega catchment of the Douro basin. A set of 29 Hydrological, climatic, and hydrogeomorphological variables were modelled using a water modelling system (MOHID), based on meteorological data recorded monthly between 2008 and 2014. The same variables were modelled considering future climate change scenarios. The resulting variables were used in empirical habitat models of a set of key species (brown trout Salmo trutta fario, barbell Barbus bocagei, and nase Pseudochondrostoma duriense) using boosted regression trees. The stream segments between tributaries were used as spatial sampling units. Models were developed for the whole Douro basin using 401 fish sampling sites, although the modelled probabilities of species occurrence for each stream segment were predicted only for the Tâmega catchment. These probabilities of occurrence were used to classify stream segments into suitable and unsuitable habitat for each fish species, considering the future climate change scenario. The stream reaches that were predicted to undergo longer flow interruptions were identified and crossed with the resulting predictive maps of habitat suitability to compute the total area of habitat loss per species. Among the target species, the brown trout was predicted to be the most sensitive to habitat regression due to the interplay of flow reduction, increase of temperature and transversal barriers. This species is therefore a good indicator of climate change impacts in rivers and therefore we recommend using this species as a target of monitoring programs to be implemented in the context of climate change adaptation strategies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2009/5094/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2009/5094/"><span>Simulation of the Regional Ground-Water-Flow System and Ground-Water/Surface-Water Interaction in the Rock River Basin, Wisconsin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Juckem, Paul F.</p> <p>2009-01-01</p> <p>A regional, two-dimensional, areal ground-water-flow model was developed to simulate the ground-water-flow system and ground-water/surface-water interaction in the Rock River Basin. The model was developed by the U.S. Geological Survey (USGS), in cooperation with the Rock River Coalition. The objectives of the regional model were to improve understanding of the ground-water-flow system and to develop a tool suitable for evaluating the effects of potential regional water-management programs. The computer code GFLOW was used because of the ease with which the model can simulate ground-water/surface-water interactions, provide a framework for simulating regional ground-water-flow systems, and be refined in a stepwise fashion to incorporate new data and simulate ground-water-flow patterns at multiple scales. The ground-water-flow model described in this report simulates the major hydrogeologic features of the modeled area, including bedrock and surficial aquifers, ground-water/surface-water interactions, and ground-water withdrawals from high-capacity wells. The steady-state model treats the ground-water-flow system as a single layer with hydraulic conductivity and base elevation zones that reflect the distribution of lithologic groups above the Precambrian bedrock and a regionally significant confining unit, the Maquoketa Formation. In the eastern part of the Basin where the shale-rich Maquoketa Formation is present, deep ground-water flow in the sandstone aquifer below the Maquoketa Formation was not simulated directly, but flow into this aquifer was incorporated into the GFLOW model from previous work in southeastern Wisconsin. Recharge was constrained primarily by stream base-flow estimates and was applied uniformly within zones guided by regional infiltration estimates for soils. The model includes average ground-water withdrawals from 1997 to 2006 for municipal wells and from 1997 to 2005 for high-capacity irrigation, industrial, and commercial wells. In addition, the model routes tributary base flow through the river network to the Rock River. The parameter-estimation code PEST was linked to the GFLOW model to select the combination of parameter values best able to match more than 8,000 water-level measurements and base-flow estimates at 9 streamgages. Results from the calibrated GFLOW model show simulated (1) ground-water-flow directions, (2) ground-water/surface-water interactions, as depicted in a map of gaining and losing river and lake sections, (3) ground-water contributing areas for selected tributary rivers, and (4) areas of relatively local ground water captured by rivers. Ground-water flow patterns are controlled primarily by river geometries, with most river sections gaining water from the ground-water-flow system; losing sections are most common on the downgradient shore of lakes and reservoirs or near major pumping centers. Ground-water contributing areas to tributary rivers generally coincide with surface watersheds; however the locations of ground-water divides are controlled by the water table, whereas surface-water divides are controlled by surface topography. Finally, areas of relatively local ground water captured by rivers generally extend upgradient from rivers but are modified by the regional flow pattern, such that these areas tend to shift toward regional ground-water divides for relatively small rivers. It is important to recognize the limitations of this regional-scale model. Heterogeneities in subsurface properties and in recharge rates are considered only at a very broad scale (miles to tens of miles). No account is taken of vertical variations in properties or pumping rates, and no provision is made to account for stacked ground-water-flow systems that have different flow patterns at different depths. Small-scale flow systems (hundreds to thousands of feet) associated with minor water bodies are not considered; as a result, the model is not currently designed for simulating site-specifi</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960012266','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960012266"><span>Numerical Prediction of Turbulent Oscillating Flow and Heat Transfer in Pipes with Various End Geometries. Ph.D. Thesis, Final Report</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oseid, Kirk Leroi</p> <p>1995-01-01</p> <p>Unsteady flow is present in man, machine and nature. The flow of blood in arteries and capillaries in the human body is pulsatile-composed of a mean flow superposed with an oscillating component. The tides that wash in and out of rivers, harbors and estuaries are unsteady flows with very long periods of oscillation. Many engineering devices employ pulsatile and oscillating flow. Pulsating flow is defined here as a periodic flow with a net displacement of fluid over each flow cycle. Oscillating flow is defined as a period flow with a zero mean over each cycle. The subject of this thesis is oscillating flow and heat transfer in pipes which make up the heater and cooler sections of the NASA Space Power Research Engine (SPRE) currently under development. This engine uses the Stirling cycle as the thermal energy converter in a power plant for future space applications. The information presented in this thesis will of course be applicable to the design of many types of machinery which employ oscillating flow and heat transfer.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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