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1

Evaluation of soil erosion as a basis of sediment yield in mountainous catchments: a preliminary study in the River Douro Basin (Northern Portugal)  

NASA Astrophysics Data System (ADS)

The River Corgo drains a meso-scale mountainous rural catchment with an area of 295 km2, underlain by crystalline rocks, in a temperate climate, which integrates the transboundary River Douro Basin, in the northeast of Portugal. A geochemical survey on oxic fluvial sediments of the river network shows considerable contents of metals associated to the finer particles (< 63um). The results on the study of the sediment properties indicate that these are essentially detrital in origin, derived from soils and weathering products. Moreover, taking into account the hydrological pattern of the catchment, the seasonal and spatial variability of metal contents associated to the sediments suggests that the control of metal in the sediments by their mineralogical, geochemical and physical properties is governed primarily at the level of the basin soils system, especially in the Wet Period, when the sediments are frequently remobilised (Reis, 2010). Although the soil particles are a common pathway of transport and entrance of metals in the fluvial network by runoff derived erosion, this mechanism is naturally more marked in mountainous catchments. Modelling sediment and adsorbed contaminant transport within catchments can help to identify possible contaminant sources, as well as to estimate the delivered quantities of eroded material and associated contaminants. In catchments with the described morphological features, monitoring the transport of sediments poses some issues concerning: (a) the low mass yield of suspended sediment from river water, under low-flow conditions; (b) the maintenance of the sediment sampler's devices in the streams, in periods of high-flow or storm events. This study describes the preliminary results of a GIS-based mass balance model of overland sediment transport to the River. The erosion, the first step of sediment transport, was estimated by an empirical model - The Universal Soil Loss Equation (USLE). The objective was to construct a GIS based potential soil loss spatial index model and posteriorly estimate the sediment yield for different locations within the catchment. The R factor was obtained from the literature; K factor was derived from the Soil Map of Trás-os-Montes; LS factor was calculated from the elevation digital model using the Simms et al. (2003) equation; C and P factors were derived from the Corin Land Cover Map produced for Portugal in 2006. The preliminary results indicate that the model is in accordance with the knowledge of the study area, and can be used as an initial indicator of areas of potential sediment source. So, the results show that potential loss is typically higher along the areas where the tributaries are deeply incised and bordered by steeper slopes, with locally extreme values. REFERENCES REIS, A. R. (2010) - Occurrence and mobilisation of non-organic micro-pollutants in mountainous riverine systems. PhD Thesis (unpublished), University of Trás-os-Montes e Alto Douro, Vila Real, 453 pp. SIMMS, A., WOODROFFE, C. & JONES, B. (2003) - Application of RUSLE for erosion management in a coastal catchment, southern NSW. MODSIM 2003: Intern. Congress on Modelling and Simulation, vol.2, Integrative Modelling of Biophysical, Social and Economic Systems for Resource Management Solutions, Australia, pp. 678-683.

Reis, Anabela; Martinho Lourenço, José M.; Parker, Andrew; Alencoão, Ana

2013-04-01

2

Analyzing catchment behavior through catchment modeling in the Gilgel Abay, Upper Blue Nile River Basin, Ethiopia  

NASA Astrophysics Data System (ADS)

Understanding catchment hydrological processes is essential for water resources management, in particular in data scarce regions. The Gilgel Abay catchment (a major tributary into Lake Tana, source of the Blue Nile) is undergoing intensive plans for water management, which is part of larger development plans in the Blue Nile basin in Ethiopia. To obtain a better understanding of the water balance dynamics and runoff generation mechanisms and to evaluate model transferability, catchment modeling has been conducted using the conceptual hydrological model HBV. Accordingly, the catchment of the Gilgel Abay has been divided into two gauged sub-catchments (Upper Gilgel Abay and Koga) and the un-gauged part of the catchment. All available data sets were tested for stationarity, consistency and homogeneity and the data limitations (quality and quantity) are discussed. Manual calibration of the daily models for three different catchment representations, i.e. (i) lumped, (ii) lumped with multiple vegetation zones, and (iii) semi-distributed with multiple vegetation and elevation zones, showed good to satisfactory model performances with Nash-Sutcliffe efficiencies Reff > 0.75 and > 0.6 for the Upper Gilgel Abay and Koga sub-catchments, respectively. Better model results could not be obtained with manual calibration, very likely due to the limited data quality and model insufficiencies. Increasing the computation time step to 15 and 30 days improved the model performance in both sub-catchments to Reff > 0.8. Model parameter transferability tests have been conducted by interchanging parameters sets between the two gauged sub-catchments. Results showed poor performances for the daily models (0.30 < Reff < 0.67), but better performances for the 15 and 30 days models, Reff > 0.80. The transferability tests together with a sensitivity analysis using Monte Carlo simulations (more than 1 million model runs per catchment representation) explained the different hydrologic responses of the two sub-catchments, which seems to be mainly caused by the presence of dambos in Koga sub-catchment. It is concluded that daily model transferability is not feasible, while it can produce acceptable results for the 15 and 30 days models. This is very useful for water resources planning and management, but not sufficient to capture detailed hydrological processes in an ungauged area.

Uhlenbrook, S.; Mohamed, Y.; Gragne, A. S.

2010-10-01

3

[Molecular-phylogenetic analysis of cyclopoids (Copepoda: Cyclopoida) from Lake Baikal and its water catchment basin].  

PubMed

Baikalian cyclopoids represent one of the richest endemic faunas of freshwater cyclopoid copepods. The genus Diacyclops Kiefer, 1927 is the most numerous by species number in the lake. In this work, molecular-phylogenetic analysis of 14 species and 1 sub-species from Lake Baikal and its water catchment basin is performed. The regions of mitochondrial cytochrom-oxydase I (COI) and of nuclear small-subunit 18S rRNA were used as evolution markers. In the obtained set of nucleotide sequences of COT gene, an effect of synonymous substitution saturation is revealed. Baikalian representatives of the genus Diacyclops form at phylogenetic schemes by two markers a monophyletic griup, it suggest their origin from a common ancestral form. Preliminary estimate of the age of this group is 20-25 My. PMID:21261066

Ma?or, T Iu; Sheveleva, N G; Sukhanova, L V; Timoshkin, O A; Kiril'chik, S V

2010-11-01

4

UPPER SNAKE RIVER BASIN, PRELIMINARY BASIN EVALUATION  

EPA Science Inventory

The purpose of this paper was to provide a process and a plan by which the Environmental Protection Agency can insure that water quality goals established in the Water Pollution Control Act Amendments of 1972 are met in the waters of the Upper Snake Basin (17040201, 17040206, 170...

5

Catchment salt balances in the Queensland Murray-Darling Basin, Australia  

NASA Astrophysics Data System (ADS)

Catchment salt mass balances and export/import ratios were calculated for 55 gauging stations in nine major catchments across the Queensland Murray-Darling Basin (QMDB), Australia. Salt inputs were comprised of atmospheric, groundwater and inter-basin transfer contributions, while exports were derived from model runs calibrated to streamflow data and flow-salt relationships. Catchment atmospheric salt inputs were larger than groundwater inputs in the major catchments, with the exception of the Condamine catchment. Across the whole QMDB, the magnitude of atmospheric and groundwater inputs is potentially equal. Average annual streamflow salt export is generally much less than salt input, even when atmospheric inputs alone are considered, and is strongly influenced by episodic, large events. The exceptions to this are some smaller salt-affected upland catchments in the eastern QMDB where flow is more continual (i.e. baseflow occurs) and stream salinity is higher - a result of long-term land use change impacts. Variability in catchment salt export/import ratio (E/I) as a result of different calculation methods for both inputs and outputs creates a wide range in possible E/I for some sites, but trends remain the same. Losses of stream water to floodplains, seepage and extractions in lower portions of catchments leads to significant reductions in E/I with distance downstream. It appears that in general, the natural status of the QMDB is one of salt accumulation and significant hydrologic changes - as represented through salt mass balance calculations - are largely confined to the eastern half of the Basin, although further change may yet express in the landscape.

Biggs, Andrew J. W.; Silburn, D. Mark; Power, R. Edward

2013-09-01

6

Using catchment similarities and flow signatures to evaluate multi-basin models  

NASA Astrophysics Data System (ADS)

Catchments with similar landscape types often generate similar flow signatures and this is normally the underlying assumption in hydrological interpretation and modelling. This presentation will explore the importance of catchment characteristics for hydrological model design, by identifying the most important landscape features and quantifying their impact on model predictions across Europe and in Sweden, respectively. Results from two multi-basin models and their databases have been used in the analysis; one for Europe including 181 gauged catchments (E-HYPE), and one for Sweden including 401 gauged catchments (S-HYPE). Each dataset is based on open data and cover catchments with a wide range in size, large variety of climatological and physiographical regions, and also with anthropogenic impacts from regulations and water abstractions. The model concept is a semi-distributed processes-based approach, using conceptual algorithms and providing daily time-series. Two different ways to evaluate the importance of catchment similarities in hydrological modelling are presented: 1) For Europe, we produced a simple correlation matrix to explore catchment similarities with several observed and modelled flow signatures, respectively. Modelled flow and observed flow signatures were also correlated. The results were used to evaluate the basic model assumptions and model usefulness when applied in a homogenous way across Europe. 2) For Sweden, we experimented with withdrawal of catchment features from an existing model to reconstruct the change in model performance, when including spatial distributed catchment characteristics and regional calibration of similar catchments. The results indicate which processes that are most dominant for flow signatures, which input data that is most sensitive for model performance and how uncertainties can been reduced most efficiently in this environment. The two examples show how models can be evaluated to provide more understanding on dominant hydrological processes and basic model assumptions than what is normally achieved from statistical criteria on model performance. The results will give direction for model improvements in the next model versions of the two model domains.

Arheimer, Berit; Andersson, Jafet; Donnelly, Chantal; Lindström, Göran

2014-05-01

7

Basin characteristics and nutrient losses: the EUROHARP catchment network perspective.  

PubMed

The EC-funded EUROHARP project studies the harmonisation of modelling tools to quantify nutrient losses from diffuse sources. This paper describes a set of study areas used in the project from geographical conditions, to land use and land management, geological and hydro-geological perspectives. The status of data availability throughout Europe in relation to the modelling requirements is presented. The relationships between the catchment characteristics and the nutrient export are investigated, using simple data available for all the catchments. In addition, this study also analyses the hydrological representativity of the time series utilised in the EUROHARP project. PMID:19280031

Bouraoui, F; Grizzetti, B; Adelsköld, G; Behrendt, H; de Miguel, I; Silgram, M; Gómez, S; Granlund, K; Hoffmann, L; Kronvang, B; Kvaernø, S; Lázár, A; Mimikou, M; Passarella, G; Panagos, P; Reisser, H; Schwarzl, B; Siderius, C; Sileika, A S; Smit, A A M F R; Sugrue, R; Vanliedekerke, M; Zaloudik, J

2009-03-01

8

Modelling catchment processes in the Swan-Avon river basin  

Microsoft Academic Search

A conceptual hydrological model, LASCAM, is applied to the Swan-Avon catchment (area 120 000 km2) in Western Australia to predict yields of water, salt, sediment, phosphorus and nitrogen. Each of the nutrients is further discriminated into soluble and particulate components. The model uses a single set of global parameters that are applied to each of the 134 subcatchments. Spatial mapping

Neil R. Viney; Murugesu Sivapalan

2001-01-01

9

Modelling catchment processes in the Swan-Avon river basin  

NASA Astrophysics Data System (ADS)

A conceptual hydrological model, LASCAM, is applied to the Swan-Avon catchment (area 120 000 km2) in Western Australia to predict yields of water, salt, sediment, phosphorus and nitrogen. Each of the nutrients is further discriminated into soluble and particulate components. The model uses a single set of global parameters that are applied to each of the 134 subcatchments. Spatial mapping of the model results shows that yields are closely related to the distribution of rainfall and vegetation cover. Application of the model to various land cover scenarios show that since European settlement in the catchment, there has been a five-fold increase in streamflow, a 40-fold increase in sediment yield, and approximately 16-fold increases in total nutrient yields.

Viney, Neil R.; Sivapalan, Murugesu

2001-09-01

10

Variability of extreme events in the Colombian Pacific and Caribbean catchment basins  

NASA Astrophysics Data System (ADS)

This paper analyses the behavior of extreme events of surface precipitation and temperature inside the Pacific and Caribbean Catchment Basins in Colombia using several datasets such as observations, reconstructed data, NCEP-NCAR and ERA-40 reanalyses and data from the regional model REMO. We use an extreme value method that selects the time series excesses over a nonstationary threshold and adjusts them to a generalized Pareto distribution. The goodness of fit is evaluated through a test that includes the Cramer-von Mises, Kolmogorov-Smirnov and Anderson-Darling statistics and the p values generated by parametric bootstrap resampling. The test not only evaluates the goodness of fit but also the threshold choice. The parameters are presented in maps that allow recognition of the features of the extreme behaviour inside the catchment basins, and differences and similarities between them. Maps of return periods for the maximum extreme events are also presented. A strong influence of the El Niño-Southern oscillation on the extreme events of both temperature and precipitation is found in the two catchment basins.

Hoyos, Isabel; Baquero-Bernal, Astrid; Jacob, Daniela; Rodríguez, Boris A.

2013-04-01

11

A participatory approach for Integrated River Basin Management in the Elbe catchment  

NASA Astrophysics Data System (ADS)

This paper presents a qualitative analysis of a series of in-depth interviews with governmental and non-governmental institutions (NGOs). Within the EUROCAT 1 project this methodology of participatory approach, aiming to scope the present perceptions about environmental issues and possible strategies for environmental improvement, is applied to the study of the Elbe catchment for the first time. In this frame, an Advisory Board (AB) was created, with the aim of giving insights into conflicting interests in the river catchment and guidelines for river basin management. Focus of the Elbe case study is the issue of nutrient enrichment (from the catchment) and the induced eutrophication of the coastal waters (the German Bight). Specifically, regarding this topic, the possible reduction of eutrophication in the German Bight by a (policy driven) decrease in nutrient inputs from the catchment area is analysed. Different measures for reducing the input of nutrients from the catchment, and ultimately preventing eutrophication of the coastal waters are considered. In this context, the members of the AB were asked about the efficiency and feasibility of different measures and the criteria for choosing 'better' management solutions among the possible ones. Although there is a general agreement about the necessity of reducing nutrient emissions, some members of the AB perceive other environmental issues (e.g. altered morphodynamics) as more relevant than nutrient enrichment. Voluntary cooperation, eco-efficiency and 'trans-sectoral' communication are the key concepts mentioned as being indispensable for integrated management. The (public) acceptance of measures for nutrient reduction have to find its way through compromises and social equity, allowing for win-win solutions among different groups of interests and balanced spatial division of costs and benefits. EUROpean CATchments, Project N° EVK1-CT-2000-00044 ( http://www.iia-cnr.unical.it/EUROCAT/project.htm).

Nunneri, C.; Hofmann, J.

2005-02-01

12

Catchment Restoration in the Tweed UNESCO-IHP HELP Basin - Eddleston Water  

NASA Astrophysics Data System (ADS)

The EU Water Frame Work Directive (WFD) requires member states to work towards the achievement of 'good ecological status' for water bodies, through a 6 year cycle of river basin management plans (RBMPs). Within these RBMPs, states must develop and implement programmes of measures designed to improve the quality of individual water bodies at risk of failing to achieve this status. These RBMPS must not only be focussed on the key causes of failure, but increasingly look to deliver multiple benefits, such as flood risk reduction and improvement to biodiversity from such catchment interventions, and to involve communities and other stakeholders in restoration of their local environment. This paper reports on progress of a detailed study of the restoration of the Eddleston Water, a typical 'failing' water body in Scotland, the monitoring and governance arrangements behind this, and implications for rehabilitation of river systems elsewhere. Within UK rivers, the main causes of failure to achieve good ecological status are historical morphological changes to river courses, diffuse agricultural pollution and invasive non-native species. The Eddleston Water is a 70 sq kms sub-catchment of the Tweed, an UNESCO IHP-HELP basin in the Scottish : English borders, and is currently classified as 'bad' status, due largely to morphological changes to the course and structure of the river over the past 200 years. The main challenge therefor is physical restoration of the river to achieve functional connectivity with the flood plain. At the same time however, the two communities within the catchment suffer from flooding, so a second priority is to intervene within the catchment to reduce the risk of flooding through the use of "natural flood management" measures and, underlying both these two aspects a whole catchment approach to community participation and the achievement of a range of other ecosystem service benefits, including conservation of biodiversity. We report on the initial characterisation of the catchment; the identification of potential key locations and types of intervention to improve ecological status and flood risk reduction; the setting up of the monitoring networks, the engagement with local communities and land managers; initial habitat modifications and the early results of the study. We situate this within the wider context of priorities for restoration and the UNESCO IHP-HELP programme.

Spray, Christopher

2013-04-01

13

Towards seasonal hydrological forecasting in mountain catchments: preliminary results from the APRIL project  

NASA Astrophysics Data System (ADS)

The APRIL project aims at addressing the long term quantitative prediction of monthly discharge from mountain catchments and setting up a system which can then be used operationally. More specifically, its objectives are: - To investigate the potential of EO products (snow cover extent, vegetation and soil moisture statust) and weather/climatic variables for the prediction of water streamflow from mountain catchments - To develop a robust methodology for the long term quantitative forecast of montly discharge from EO and weather/climatic data - To build a fully operational system for seasonal hydrological forecasting. This contribution illustrates the general concept of the project as well as some preliminary results. Water discharge in mountain catchments is physically related to antecedent snow cover and climatology (precipitation, temperature). Other factors may play a role, such as vegetation/soil status and topography. Historical discharge measurements and earth observation (EO) data are a valuable source for inferring the quantitative relationship between the discharge and its predictors using appropriate techniques. The prediction is based on the Support Vector Regression (SVR)technique, a state of the art machine learning regression method with good intrinsic generalization ability and robustness. In the contribution we present and discuss results of a preliminary analysis on water discharge prediction ( with lead time of 1 to 3 months) in South Tyrol, Italy. Despite the use of a limited set of predictors (among which mainly snow cover area), the results are encouraging. The analysis is in the process of being extended at different spatial scales, which will give the possibility to investigate different aspects of the problem and develop different prediction systems; by updating on the current developments, the contribution discusses also perspectives and current limitations towards the set up of a fully operational seasonal hydrological forecasting system in Europe.

Pistocchi, Alberto; Mazzoli, Paolo; Bagli, Stefano; Notarnicola, Claudia; Pasolli, Luca

2013-04-01

14

Ecosystem based river basin management planning in critical water catchment in Mongolia  

NASA Astrophysics Data System (ADS)

Developing the ecosystem based adaptation strategies to maintain water security in critical water catchments in Mongolia would be very significant. It will be base by reducing the vulnerability. "Ecosystem Based adaptation" is quite a new term in Mongolia and the ecosystem approach is a strategy for the integrated management of land, water and living resources that promotes conservation and sustainable use in an equitable way. To strengthen equitable economic development, food security, climate resilience and protection of the environment, the implementation of sustainable river basin management in critical water catchments is challenging in Mongolia. The Ulz river basin is considered one of the critical water catchments due to the temperature has increased by in average 1.30Ñ over the period 1976 to 2011. It is more intense than the global warming rate (0.740C/100 years) and a bit higher than the warming rate over whole Mongolia as well. From long-term observations and measurements it is clear that Ulz River has low water in a period of 1970-1980 and since the end of 1980s and middle of 1990s there were dominated years of the flood. However, under the influence of the global warming, climate changes of Mongolia and continuation of drought years with low water since the end of 1990s until today river water was sharply fallen and dried up. For the last ten years rivers are dried up and annual mean run-off is less by 3-5 times from long term mean value. The Ulz is the transboundary river basin and taking its origin from Ikh and Baga Burd springs on territory of Norovlin soum of Khentii province that flows through Khentii and Dornod provinces to the northeast, crossing the state border it flows in Baruun Tari located in Tari Lake concavity in Russia. Based on the integrative baseline study on the 'The Ulz River Basin Environmental and Socioeconomic condition', ecosystem based river basin management was planned. 'Water demand Calculator 3' (WDC) software was used to estimate water demand and calculate water use balance in 2015, 2021. The result of the water balance estimation shows that water consumption-use will be increased 3 times in the river basin by 2021. As the water consumption-use source, surface water - 6.4 % and groundwater is 93.6 percent. The current consumption of the mining sector is shares 71 percent of the total users; it would be 82 percent in 2021. However, the livestock water consumption-use is 27 percent of the current demand; it would be decrease up to 16 percent in 2021. Ecosystem based approach IWRM plan would be efficient to the local resident to adapt the climate change situation. Thus, the results of the research study on the river basin ecosystem services and values are the base of the planning.

Tugjamba, Navchaa; Sereeter, Erdenetuul; Gonchigjav, Sarantuya

2014-05-01

15

Mn-oxides and sequestration of heavy metals in a suburban catchment basin of the Chesapeake Bay watershed  

Microsoft Academic Search

The Chesapeake Bay is greatly impacted by numerous pollutants including heavy metals and understanding the controls on the\\u000a distribution of heavy metals in the watershed is critical to mitigation and remediation efforts in controlling this type of\\u000a pollution. Clasts from a stormwater catchment basin draining a subdivision near George Mason University, Fairfax VA (38°50.090°N\\u000a 78°19.204°W) were investigated using X-ray diffraction

James P. Adams; Robert Kirst; Lance E. Kearns; Mark P. S. Krekeler

2009-01-01

16

Mn-oxides and sequestration of heavy metals in a suburban catchment basin of the Chesapeake Bay watershed  

Microsoft Academic Search

The Chesapeake Bay is greatly impacted by numerous pollutants including heavy metals and understanding the controls on the distribution of heavy metals in the watershed is critical to mitigation and remediation efforts in controlling this type of pollution. Clasts from a stormwater catchment basin draining a subdivision near George Mason University, Fairfax VA (38°50.090°N 78°19.204°W) were investigated using X-ray diffraction

James P. Adams; Robert Kirst; Lance E. Kearns; Mark P. S. Krekeler

2009-01-01

17

Attributes for MRB_E2RF1 Catchments in Selected Major River Basins: Population Density, 2000  

USGS Publications Warehouse

This data set represents the average population density, in number of people per square kilometer multiplied by 10 for the year 2000, compiled for every MRB_E2RF1 catchment of selected Major River Basins (MRBs, Crawford and others, 2006). The source data set is the 2000 Population Density by Block Group for the Conterminous United States (Hitt, 2003). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) RF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

18

Catchments by Major River Basins in the Conterminous United States: 30-Year Average Daily Minimum Temperature, 1971-2000  

USGS Publications Warehouse

This tabular data set represents thecatchment-average for the 30-year (1971-2000) average daily minimum temperature in Celsius multiplied by 100 compiled for every MRB_E2RF1 catchment of selected Major River Basins (MRBs, Crawford and others, 2006). The source data were the United States Average Monthly or Annual Minimum Temperature, 1971 - 2000 raster data set produced by the PRISM Group at Oregon State University. The MRB_E2RF1 catchments are based on a modified version of the Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

19

Neogene and Quaternary development of the Turiec Basin and landscape in its catchment: a tentative mass balance model  

NASA Astrophysics Data System (ADS)

The development of the Turiec Basin and landscape evolution in its catchment has been reconstructed by methods of geological research (structural geology, sedimentology, paleoecology, and geochronological data) as well as by geophysics and geomorphology. The basin and its surrounding mountains were a subject of a mass balance study during periods of tectonic activity, accompanied by considerable altitudinal differentiation of relief and also during quiet periods, characterized by a development of planation surfaces in the mountains. The coarse clastic alluvial fans deposited beneath the offshore pelitic sediments document the rapid Middle Miocene uplift of mountains on the margin of the Turiec Basin. The Late Miocene finegrained sedimentation represents the main fill of this basin and its origin was associated with the formation of planation surfaces in the surrounding mountains. The rapid uplift of the western and northern parts of the catchment area during the latest Miocene and Early Pliocene times further generated the deposition of coarse-grained alluvial fans. The Late Pliocene basin inversion, due to uplift of the whole Western Carpathians mountain chain, was associated with the formation of the Early Quaternary pediment and ultimately with the formation of the Turiec river terrace systems.

Ková?, Michal; Hók, Jozef; Minár, Jozef; Vojtko, Rastislav; Bielik, Miroslav; Pipík, Radovan; Rakús, Miloš; Krá?, Ján; Šujan, Martin; Králiková, Silvia

2011-08-01

20

Transient catchment hydrology after wildfires in a Mediterranean basin: runoff, sediment and woody debris  

NASA Astrophysics Data System (ADS)

The transient effect of forest fires on runoff, erosion and yield of woody biomass has been investigated by combining the experimental approach with mathematical models of hydrological processes. The case study is the Branega creek in Liguria, Italy, where a forest fire in August 2003 caused substantial changes to soil and vegetation, and left a considerable amount of woody debris on the ground. Immediately after the fire, rainfall simulator experiments in adjacent burned and unburned plots showed the extent to which fire had increased runoff and erosion rates. A distributed hydrological model using the tube-flux approach, calibrated on experimental measurements, has been used to investigate hill slope and channel erosion in a small sub-catchment, 1.5 ha in area, nested in the Branega basin. Simulation runs show that the model accommodates the observed variability of runoff and erosion under disturbed and undisturbed conditions. A model component describing the delivery of wood from hill slopes to the channel in post-fire conditions, validated against local survey data, showed that the removal and transport of woody biomass can be reproduced using an integrated hydrological approach. Hence, transient complexity after wildfires can be addressed by such an approach with empirically determined physically-based parameters.

Rosso, R.; Rulli, M. C.; Bocchiola, D.

2007-01-01

21

Hydrochemical Linkage of Groundwater and Surface Water in a Small Catchment Basin, SE Massachusetts  

NASA Astrophysics Data System (ADS)

Wildcat and Third Herring Brooks drain a small catchment basin approximately 8.2 sq.mi in size located in a moderately populated region in southeastern Massachusetts. Both streams flow through a semi-urban partially developed forested land with no municipal sewer system and with varied density of roads serviced in the winter season with deicing chemicals. Two towns (Hanover and Norwell) share the underlying aquifer by pumping on average 1.5 Mgal per day, a rate which significantly influences infiltration / discharge patterns and seasonal water budget. The aquifer is situated in a buried valley filled with glacial outwash deposits in some parts and peat deposits underneath wetlands in others. Correspondingly, water quality within the aquifer reflects these two distinct geological surficial enviroregions. Anerobic reducing water enriched in Fe and Mn is associated with the peat layers and oxygenated, low Fe and Mn water exists in the outwash subregion. Normal flow of ground water parallels the boundary between these ecoregions with a minimal mixing between these two hydrochemical ground water domains. However, water withdrawal during pumping tests showed that both ground water types can mix with a formation of precipitates of Fe and Mn hydroxides. Water quality is also influenced by dissolution of deicing chemicals. Water drawn from wells located closer to the streams have higher sodium and chloride concentrations than water in the wells located further away. Planning and management of water supply resources has to take into account variations of hydrochemical characteristics within the aquifer as well as the extent of interactions between the streams and the ground water system.

Hon, R.; Dillon, P.; Merritt, N.

2004-05-01

22

Catchment modeling and model transferability in upper Blue Nile Basin, Lake Tana, Ethiopia  

NASA Astrophysics Data System (ADS)

Understanding spatial and temporal distribution of water resources has an important role for water resource management. To understand water balance dynamics and runoff generation mechanisms at the Gilgel Abay catchment (a major tributary into lake Tana, source of Blue Nile, Ethiopia) and to evaluate model transferability, catchment modeling was conducted using the conceptual hydrological model HBV. The catchment of the Gigel Abay was sub-divided into two gauged sub-catchments (Upper Gilgel Abay, UGASC, and Koga, KSC) and one ungauged sub-catchment. Manual calibration of the daily models for three different catchment representations (CRs): (i) lumped, (ii) lumped with multiple vegetation zones, and (iii) semi-distributed with vegetations zone and elevation zones, showed good to satisfactory model performance (Nash-Sutcliffe efficiency values, Reff>0.75 and >0.6, respectively, for UGASC and KSC). The change of the time step to fifteen and thirty days resulted in very good model performances in both sub-catchments (Reff>0.8). The model parameter transferability tests conducted on the daily models showed poor performance in both sub-catchments, whereas the fifteen and thirty days models yielded high Reff values using transferred parameter sets. This together with the sensitivity analysis carried out after Monte Carlo simulations (1 000 000 model runs) per CR explained the reason behind the difference in hydrologic behaviors of the two sub-catchments UGASC and KSC. The dissimilarity in response pattern of the sub-catchments was caused by the presence of dambos in KSC and differences in the topography between UGASC and KSC. Hence, transferring model parameters from the view of describing hydrological process was found to be not feasible for all models. On the other hand, from a water resources management perspective the results obtained by transferring parameters of the larger time step model were acceptable.

Gragne, A. S.; Uhlenbrook, S.; Mohammed, Y.; Kebede, S.

2008-03-01

23

Paired Catchment Modeling Study for a Monsoon Flood Event in Neighboring Semi-Arid Basins, New Mexico  

NASA Astrophysics Data System (ADS)

Flooding in ephemeral stream networks can significantly impact channel geomorphology, sediment transport, biogeochemical cycles, and water availability for consumptive and recreational use. In order to better understand the spatial patterns of flooding, distributed models may provide an opportunity for further investigation of rainfall-runoff dynamics in headwater semi-arid catchments including flood generation in ungauged portions of a watershed. For example, the Rio Puerco in west-central New Mexico is an ephemeral tributary of the Rio Grande spanning approximately 18,896 km2 with mountainous forests to the north and semi-arid desert to the south. In mid-September 2003, a series of late monsoonal storms traversed the northern extent of watershed resulting in a flood pulse which propagated through the main reach of the catchment and into the Rio Grande thereby substantially influencing streamflow as far south as Elephant Butte Reservoir (289 km). Radar data suggests flooding most likely emanated from two neighboring sub-catchments within the upper reaches of the watershed. In order to better understand the source of significant hydrologic events within the catchment, we utilize a fully distributed model to simulate the flood within the gauged Upper Rio Puerco Watershed (1119 km2) as well as the immediately adjacent but ungauged Torreon Wash (1344 km2). The TIN-Based Real-time Integrated Basin Simulator (tRIBS) prioritizes interactions between the vadose and saturated zone through the simulation of downward moving infiltration fronts and a variable groundwater surface. Topography is captured through a multiple resolution triangular irregular network (TIN) which accurately represents changes in elevation and simultaneously diminishes the model's computational demands. In addition to faithfully modeling topographic features, tRIBS requires accurate representation and calibration of soil, land use features, and geomorphic data. Calibration is performed through a manual procedure in which parameter values are adjusted in an effort to match an observed stream hydrograph with the model output for a series of storm and inter-storm periods. Following model calibration, we transfer the parameter set to the neighboring Torreon Wash. Model results for the paired catchment study demonstrate the appropriateness of parameter transfer between two neighboring semi-arid catchments.

Wyckoff, R. L.; Vivoni, E. R.

2005-12-01

24

Daily anomalous high flow (DAHF) of a headwater catchment over the East River basin in South China  

NASA Astrophysics Data System (ADS)

This study develops a new method for analyzing the terrestrial hydrologic responses to precipitation through using level-based daily anomalous high flow (DAHF) occurrence in a catchment. The objectives of this study are twofold: (1) to explore the DAHF features over a headwater catchment; and (2) to evaluate the performance of a hydrologic model for DAHF simulation. In this study, DAHF is defined as the daily streamflow on a given day, whose deseasonalised daily streamflow is larger than a given multiplier of the standard deviation (STD) of the long-term deseasonalised streamflow series. Streamflow observations of a headwater catchment over the period of 1952-1972 (i.e., before reservoir operation) at the Longchuan station in the East River basin in South China are studied. The macro-scale Variable Infiltration Capacity (VIC) model is used for streamflow simulation in the catchment, and wavelet analysis is performed to explore the DAHF variability. The study reveals that the percentages of the number of days with the first and second levels of DAHFs are 4.2% and 1%, respectively, for the observed streamflows, while the corresponding percentages for the VIC model-simulated streamflow are 5% and 1.3%, respectively. Application of the Kolmogorov-Smirnov goodness-of-fit test indicates that these two levels of DAHFs can be described by two probability distribution functions, namely the Lognormal distribution and Generalized Extreme Value Type II distribution, respectively. The variability spectrum of the first level DAHF is basically consistent with that of antecedent precipitation, but not for the second level DAHF, as revealed by the wavelet analysis. The VIC model has better performance on the variability simulation of the first level of DAHF.

Chen, Ji; Niu, Jun; Sivakumar, Bellie

2014-11-01

25

Soil and plant composition in the Noun river catchment basin, Western Cameroon: a contribution to the development of a biogeochemical baseline  

NASA Astrophysics Data System (ADS)

Soils and selected edible plants of the Noun river catchment basin of western Cameroon were sampled to investigate the distribution of trace elements, based on the preliminary idea of unusual anomalies. Analytical techniques for trace elements included ICP-AES, GF-AAS, and ICP-MS. Further soil analyses comprised the mineralogy and contents of the biogenic elements carbon, nitrogen and sulphur (CNS). The trace element concentrations in the soils reflect those of the lithogeochemical background of the pluto-volcanic rocks of the region. This is consistent with the results from the mineralogical analyses and physicochemical parameters such as pH, taken in the field, which also do not suggest any geochemical anomaly. Most trace elements analyzed in the plants showed concentrations that reflect those of the soils (Al, Fe, Ti, and Rb). However, some trace elements were enriched in the plants as compared to the soils, such as Zn, Cu, Cd, Mo (excluding yam), Ni (peanut), Ba (peanut), Sr (peanut, bean), and B. Trace elements such as As, Cr, V, and Se were not bioavailable for all the analyzed plants. Besides, trace elements such as Cu, Zn, Mo, Fe, Al, Ni, B, Ti, Rb, Cs, and Ba were in the range of phytotoxicity and reached or exceeded human food tolerance level (Cu). The plants with seeds showed a higher absorption of trace elements compared to plants with tubercles.

Njofang, Clémentine; Matschullat, Jörg; Amougou, Akoa; Tchouankoué, Jean Pierre; Heilmeier, Hermann

2009-02-01

26

Monitoring of fluvial transport in small upland catchments - methods and preliminary results  

NASA Astrophysics Data System (ADS)

In April 2011 a study was initiated, financed from resources of the Polish National Science Centre, entitled: ‘Rainstorm prediction and mathematic modelling of their environmental and social-economical effects’ (No. NN/306571640). The study, implemented by a Polish-American team, covers meteorological research, including: (1) monitoring of single cell storms developing in various synoptic situations, (2) detection of their movement courses, and (3) estimation of parameters of their rain field. Empirical studies, including hydrological and geomorphological measurements, are conducted in objects researched thoroughly in physiographic terms (experimental catchments) in the Lublin region (SE Poland), distinguished by high frequency of occurrence of the events described. For comparative purposes, studies are also carried out on selected model areas in the lower course of the Mississippi River valley (USA), in a region with high frequency of summer rainstorms. For detailed studies on sediment transport processes during rainstorm events, catchments of low hydrological rank and their sub-catchments in a cascade system were selected. For the basic, relatively uniform geomorpho logical units distinguished this way, erosion and deposition balance of material transported was determined. The aim of work was to determine influence of weather condition on fluvial transport rate in small catchment with low hydrological order

Janicki, Grzegorz; Rodzik, Jan; Chabudzi?ski, ?ukasz; Franczak, ?ukasz; Si?uch, Marcin; St?pniewski, Krzysztof; Dyer, Jamie L.; Ko?odziej, Grzegorz; Maciejewska, Ewa

2014-06-01

27

A Lagrangian Analysis of the Atmospheric Branch of the Global Water Cycle. Part II: Moisture Transports between Earth's Ocean Basins and River Catchments  

Microsoft Academic Search

A diagnostic Lagrangian method to trace the budgets of freshwater fluxes, first described in Part I of this article, is used here to establish source-sink relationships of moisture between earth's ocean basins and river catchments. Using the Lagrangian particle dispersion model FLEXPART, driven with meteorological analyses, 1.1 million particles, representing the mass of the atmosphere, were tracked over a period

Andreas Stohl; Paul James

2005-01-01

28

Spatial and Seasonal Patterns of Natural Organic Matter Spectral Fluorescent Signatures in Lake Kinneret (Sea of Galilee) and its Catchment Basin  

Microsoft Academic Search

This paper presents a characterization of fluorescent natural organic matter (NOM) in Lake Kinneret (Sea of Galilee) and its catchment basin. Lake Kinneret, the large high-productive subtropical lake, is the only freshwater lake and one of the major water resources in Israel. The work is based on the analysis of the spectral fluorescent signatures (excitation emission matrices; EEM) of 167

M. Borisover; Y. Laor; A. Parparov; N. Bukhanovsky; M. Lado

2009-01-01

29

The Immatsiak network of groundwater wells in a small catchment basin in the discontinuous permafrost zone of Northern Quebec, Canada: A unique opportunity for monitoring the impacts of climate change on groundwater (Invited)  

NASA Astrophysics Data System (ADS)

During a summer drilling campaign in 2012, a network of nine groundwater monitoring wells was installed in a small catchment basin in a zone of discontinuous permafrost near the Inuit community of Umiujaq in Northern Quebec, Canada. This network, named Immatsiak, is part of a provincial network of groundwater monitoring wells to monitor the impacts of climate change on groundwater resources. It provides a unique opportunity to study cold region groundwater dynamics in permafrost environments and to assess the impacts of permafrost degradation on groundwater quality and availability as a potential source of drinking water. Using the borehole logs from the drilling campaign and other information from previous investigations, an interpretative cryo-hydrogeological cross-section of the catchment basin was produced which identified the Quaternary deposit thickness and extent, the depth to bedrock, the location of permafrost, one superficial aquifer located in a sand deposit, and another deep aquifer in fluvio-glacial sediments and till. In the summer of 2013, data were recovered from water level and barometric loggers which were installed in the wells in August 2012. Although the wells were drilled in unfrozen zones, the groundwater temperature is very low, near 0.4 °C, with an annual variability of a few tenths of a degree Celsius at a depth of 35 m. The hydraulic head in the wells varied as much as 6 m over the last year. Pumping tests performed in the wells showed a very high hydraulic conductivity of the deep aquifer. Groundwater in the wells and surface water in small thermokarst lakes and at the catchment outlet were sampled for geochemical analysis (inorganic parameters, stable isotopes of oxygen (?18O) and hydrogen (?2H), and radioactive isotopes of carbon (?14C), hydrogen (tritium ?3H) and helium (?3He)) to assess groundwater quality and origin. Preliminary results show that the signature of melt water from permafrost thawing is observed in the geochemistry of groundwater and surface water at the catchment outlet. Following synthesis of the available information, including a cryo-hydrogeophysical investigation in progress, a three-dimensional hydrogeological conceptual and numerical model of the catchment basin will be developed. According to different scenarios of climate change, the potential of using groundwater as a sustainable resource in northern regions will be assessed by simulating the present and future impacts of climate change on this groundwater system.

Fortier, R.; Lemieux, J.; Molson, J. W.; Therrien, R.; Ouellet, M.; Bart, J.

2013-12-01

30

Groundwater storage change in the Ngadda Catchment of the Lake Chad Basin using GRACE and ground truth data  

NASA Astrophysics Data System (ADS)

The present study is to analyze groundwater storage variations in the Ngadda Catchment located in the southwestern edge of Lake Chad Basin using Gravity Recovery and Climate Experiment (GRACE) data. We collected monthly total water storage data from GRACE and monthly soil moisture data from Global Land Data Assimilation System (GLDAS) for the period of 2005 - 2009 with the spatial resolution of 1 and 0.25 degrees. We assumed surface water contributions to be negligible in the study area. The estimated groundwater storage changes were compared to the ground truth groundwater depth data collected in 2005 and 2009. The challenge of the present study is sparseness of the ground truth data in space and time. The study area is one of the data poor regions in the world due to the limited accessibility to the area. Different geostatistical techniques such as Kriging, Thiessen polygons, and Bayesian updating were applied to overcome such sparseness and modeling uncertainty under different scales and resolution. The study shows a significant increase of groundwater storage in the Ngadda catchment during the study period. Uncertainty is significant though depending on the size of the model and modeling technique. The study discusses advantages of using remote sensing data in data poor regions and how geostatistical techniques can be applied to deal with modeling uncertainty.

Skaskevych, A.; Lee, J.

2013-12-01

31

Catchment-scale biogeochemical filtering: A preliminary evaluation of chemical export in four Experimental Watersheds. (Invited)  

NASA Astrophysics Data System (ADS)

Catchments may be conceptualized as hydrological, biological and geochemical filters, which, forced by precipitation, generate patterns of flow and chemical export. We examine these patterns to obtain insight into the operation of the filters, and consequently into key process interactions within catchments. This study examined patterns of precipitation, flow, nutrient and weathering export from four Experimental Watersheds (Hubbard Brook, Loch Vale, HJ Andrews and Fernow). The following questions guided the study: 1) How was precipitation linked to patterns in stream flow? 2) What patterns emerged with respect to hydrology and chemistry, and how did they vary across sites? 3) Which time scales appeared to be important? Hydrologically, large differences in precipitation-flow patterns emerged at annual and within-year timescales, which appeared to be linked to variability in snowpack density and timing of snowmelt. Across the majority of sites and for a majority of chemical species examined, apparent chemostatic behavior was observed at seasonal timescales, such that the variability in flow-weighted concentration was small in comparison to the variability in hydrological drivers. The variations in the magnitude of this concentration between sub-catchments and between research sites were influenced by geology and atmospheric deposition. Exceptions to the apparent chemostatic response were also observed, notably in bioactive compounds. Potential process controls and decoupling between hydrologic and biogeochemical processes that might lead to such chemostatic behavior are discussed.

Moravec, B. G.; Thompson, S. E.; Aubeneau, A. F.; Ye, S.; Rao, P. C.; Basu, N. B.; Brooks, P. D.; Troch, P. A.

2009-12-01

32

Analysis of catchment behavior using residence time distributions with application to the Thuringian Basin  

NASA Astrophysics Data System (ADS)

Residence time distribution (RTD), as presented e.g. by Botter et al., are a novel mathematical framework for a quantitative characterization of hydrological systems. These distributions contain information about water storage, flow pathways and water sources and therefore improve the classical hydrograph methods by allowing both nonlinear as well as time-dependent dynamics. In our study we extend this previous works by applying this theoretical framework on real-world heterogeneous catchments. To that end we use a catchment-scale hydrological model (mHM) and apply the approach of Botter et al. to each spatial grid cell of mHM. To facilitate the coupling we amended Botter's approach by introducing additional fluxes (like runoff from unsaturated zone) and specifying the structure of the groundwater zone. By virtue of this coupling we could then make use of the realistic hydrological fluxes and state variables as provided by mHM. This allowed us to use both observed (precipitation, temperature, soil type etc.) and modeled data sets and asses their impact on the behavior of the resulting RTD's. We extended the aforementioned framework to analyze large catchments by including geomorphic effect due to the actual arrangement of subcatchments around the channel network using the flood routing algorithm of mHM. Additionally we study dependencies of the stochastic characteristics of RTD's on the meteorological and hydrological processes as well as on the morphological structure of the catchment. As a result we gained mean residence times (MRT) of base flow and groundwater flow on the mesoscale (4km x 4km). We compare the spatial distribution of MRT's with land cover and soil moisture maps as well as driving forces like precipitation and temperature. Results showed that land cover is a major predictor for MRT's whereas its impact on the mean evapotranspiration time was much lower. Additionally we determined the temporal evolution of mean travel times by using time series of all relevant hydrological processes (observed as well as modeled by mHM) from 1960-2010. Our analysis revealed the strong regularity of the catchment dynamics over long time periods. The strong seasonal changes of MRT's, usually modeled by sine-wave approach, could be approximated by sawtooth-wave model. Our future work will be focused on comparing of our numerical results with realistic data from tracer experiments and isotope measurements.

Prykhodko, Vladyslav; Heße, Falk; Kumar, Rohini; Samaniego, Luis; Attinger, Sabine

2014-05-01

33

Properties and development of channel calcretes in a mountain catchment, Tabernas Basin, southeast Spain  

Microsoft Academic Search

Nonpedogenic channel calcretes of up to 3.5 m thick occur in a number of locations across the Tabernas Basin in Almer??a Province, southeast Spain. They represent the last major phase of late Quaternary calcium carbonate cementation to affect this semiarid drainage basin. Channel calcretes are situated within the basal parts of sequences of Results indicate that all channel calcretes are

David J. Nash; Roger F. Smith

2003-01-01

34

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Average Atmospheric (Wet) Deposition of Inorganic Nitrogen, 2002  

USGS Publications Warehouse

This tabular data set represents the average atmospheric (wet) deposition, in kilograms per square kilometer, of inorganic nitrogen for the year 2002 compiled for every catchment for MRB_E2RF1 of Major River Basins (MRBs, Crawford and others, 2006). The source data set for wet deposition was from the USGS's raster data set atmospheric (wet) deposition of inorganic nitrogen for 2002 (Gronberg, 2005). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every catchment of MRB_E2RF1 catchments for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

35

Evaluation and inter-comparison of Global Climate Models’ performance over Katonga and Ruizi catchments in Lake Victoria basin  

NASA Astrophysics Data System (ADS)

Regional impact assessments of climate change on hydrological extremes require robust examinations of climate model simulations. The climate models may satisfy mean statistics but fail to reproduce extreme quantiles which are crucial for applications of climate change impact analysis on water resources. Through statistical analysis, this paper evaluates and inter-compares the performance of Global Climate Model (GCM) simulations for their ability to predict changes in hydrological extremes for given locations or catchments in the Nile basin. Two catchments were considered: Katonga and Ruizi catchments in the Lake Victoria basin. Models that differ significantly from the observed extremes were considered unreliable for impact assessments on hydrological extremes. A graphical approach (rainfall quantile/frequency analysis), which allows for easy spotting of discordant models, in combination with several statistics, was used to evaluate 18 GCM control simulations against observed rainfall data. Standard deviation, coefficient of variation and root mean squared error (about the mean) of the observed rainfall, were used to derive error margins against which GCM simulations were evaluated. Model results outside the error margins were considered inconsistent with the observed rainfall. Model inter-comparison was also carried out for the rainfall change projections till the 2050s and 2090s through analysis of perturbations and percentage changes based on A1B, A2, and B1 SRES scenarios. It is noted that the GCM outputs are more consistent in reproducing rainfall signatures at annual aggregation level than at monthly aggregation levels with tendency of overestimation of the rainfall depths but with significant variation among different GCM simulations. The GCMs perform better in reproducing rainfall frequency with higher return periods compared with lower return periods. Most of the GCMs perform better for the wet months than the drier months. The GCMs CGCM3.2a, CM3.O, CM4.1, PCM1, CGCM3.1T47, MIROC3.2.HIRES, CCSM3.0 and FGOALS, are the most inconsistent with the observed rainfall for both catchments. Good performing models are MK3.5, MK3.0, ECHAM5, CM2.1U.H2 and CM2.0. In general, most GCMs perform poorly for both catchments. This signals the need for significant improvements in the rainfall modelling of the climate models for the study region. There is no strong evidence to suggest that GCM performance improves with higher spatial resolution. Models which are highly inconsistent with other models in reproducing the observed rainfall are not necessarily inconsistent with other models in the future projections. Differences in projections for the A1B, B2, and B1 scenarios were found to be smaller than the differences between the GCM simulations.

Nyeko-Ogiramoi, P.; Ngirane-Katashaya, G.; Willems, P.; Ntegeka, V.

36

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Basin Characteristics, 2002 Geospatial_Data_Presentation_Form: tabular digital data  

USGS Publications Warehouse

This tabular data set represents basin characteristics for the year 2002 compiled for every MRB_E2RF1 catchment of selected Major River Basins (MRBs, Crawford and others, 2006). These characteristics are reach catchment shape index, stream density, sinuosity, mean elevation, mean slope and number of road-stream crossings. The source data sets are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) RF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011) and the U.S. Census Bureau's TIGER/Line Files (U.S. Census Bureau,2006). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

37

A semi-distributed integrated flow and nitrogen model for multiple source assessment in catchments (INCA): Part II — application to large river basins in south Wales and eastern England  

Microsoft Academic Search

The integrated nitrogen in catchments (INCA) model is applied to two large river basins, the River Tywi in south Wales and the Great Ouse in eastern England. These two catchments have contrasting hydrogeology, land use and climatic regimes and provide an interesting test of the INCA model. The model is calibrated and validated against hydrological and chemical data for the

P. G Whitehead; E. J Wilson; D Butterfield; K Seed

1998-01-01

38

Environmental flows allocation in river basins: Exploring allocation challenges and options in the Great Ruaha River catchment in Tanzania  

NASA Astrophysics Data System (ADS)

Provision for environmental flows is currently becoming a central issue in the debate of integrated water resources management in river basins. However, the theories, concepts and practical applications are still new in most developing countries with challenging situations arising in complex basins with multiple water uses and users and increasing water demands and conflicts exemplified by the Great Ruaha River catchment in Tanzania. The research has shown that a flow of 0.5-1 m 3/s for Great Ruaha River through the Ruaha National Park is required to sustain the environment in the park during the dry season. But a question is how can this be achieved? This paper reviews the challenges and suggests some options for achieving environmental water allocation in river basins. The following challenges are identified: (a) the concept of environmental flows is still new and not well known, (b) there is limited data and understanding of the hydrologic and ecological linkages, (c) there is insufficient specialist knowledge and legislative support, (d) there are no storage reservoirs for controlled environmental water releases, and (e) there are contradicting policies and institutions on environmental issues. Notwithstanding these challenges, this paper identifies the options towards meeting environmental water allocation and management: (a) conducting purposive training and awareness creation to communities, politicians, government officials and decision makers on environmental flows, (b) capacity building in environmental flows and setting-up multidisciplinary environmental flows team with stakeholders involvement, (c) facilitating the development of effective local institutions supported by legislation, (d) water harvesting and storage and proportional flow structures design to allow water for the environment, and (e) harmonizing policies and reform in water utilization and water rights to accommodate and ensure water for the environment.

Kashaigili, Japhet J.; Kadigi, Reuben M. J.; Lankford, Bruce A.; Mahoo, Henry F.; Mashauri, Damus A.

39

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Average Daily Minimum Temperature, 2002  

USGS Publications Warehouse

The MRB_E2RF1 catchments are based on a modified version of the Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

40

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Average Daily Maximum Temperature, 2002  

USGS Publications Warehouse

The MRB_E2RF1 catchments are based on a modified version of the Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2008). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

41

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: 30-Year Average Annual Precipitation, 1971-2000  

USGS Publications Warehouse

This tabular data set represents the 30-year (1971-2000) average annual precipitation in millimeters multiplied by 100 compiled for every MRB_E2RF1 catchment of selected Major River Basins (MRBs, Crawford and others, 2006). The source data were the United States Average Monthly or Annual Minimum Precipitation, 1971 - 2000 raster data set produced by the PRISM Group at Oregon State University. The MRB_E2RF1 catchments are based on a modified version of the Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; J.W. Brakebill, U.S. Geological Survey, written commun., 2008). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

42

Post-wildfire recovery of water yield in the Sydney Basin water supply catchments: An assessment of the 2001/2002 wildfires  

NASA Astrophysics Data System (ADS)

Wildfire is a recurring event which has been acknowledged by the literature to impact the hydrological cycle of a catchment. Hence, wildfire may have a significant impact on water yield levels within a catchment. In Australia, studies of the effect of fire on water yield have been limited to obligate seeder vegetation communities. These communities regenerate from seed banks in the ground or within woody fruits and are generally activated by fire. In contrast, the Sydney Basin is dominated by obligate resprouter communities. These communities regenerate from fire resistant buds found on the plant and are generally found in regions where wildfire is a regular occurrence. The 2001/2002 wildfires in the Sydney Basin provided an opportunity to investigate the impacts of wildfire on water yield in a number of catchments dominated by obligate resprouting communities. The overall aim of this study was to investigate whether there was a difference in water yield post-wildfire. Four burnt subcatchments and 3 control subcatchments were assessed. A general additive model was calibrated using pre-wildfire data and then used to predict post-wildfire water yield using post-wildfire data. The model errors were analysed and it was found that the errors for all subcatchments showed similar trends for the post-wildfire period. This finding demonstrates that wildfires within the Sydney Basin have no significant medium-term impact on water yield.

Heath, J. T.; Chafer, C. J.; van Ogtrop, F. F.; Bishop, T. F. A.

2014-11-01

43

Attributes for MRB_E2RF1 Catchments in Selected Major River Basins of the Conterminous United States: Contact Time, 2002  

USGS Publications Warehouse

This tabular data set represents the average contact time, in units of days, compiled for every MRB_E2RF1 catchment of Major River Basins (MRBs, Crawford and others, 2006). Contact time, as described in Vitvar and others (2002), is defined as the baseflow residence time in the subsurface. The source data set was the U.S. Geological Survey's (USGS) 1-kilometer grid for the conterminous United States (D.M. Wolock, U.S. Geological Survey, written commun., 2008). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) RF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

44

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Mean Infiltration-Excess Overland Flow, 2002  

USGS Publications Warehouse

This tabular data set represents the mean value for infiltration-excess overland flow as estimated by the watershed model TOPMODEL, compiled for every MRB_E2RF1 catchment of the Major River Basins (MRBs, Crawford and others, 2006). The source data set is Infiltration-Excess Overland Flow Estimated by TOPMODEL for the Conterminous United States (Wolock, 2003). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

45

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Normalized Atmospheric Deposition for 2002, Total Inorganic Nitrogen  

USGS Publications Warehouse

This tabular data set represents the average normalized atmospheric (wet) deposition, in kilograms per square kilometer multiplied by 100, of Total Inorganic Nitrogen for the year 2002 compiled for every MRB_E2RF1 catchment of selected Major River Basins (MRBs, Crawford and others, 2006). Estimates of Total Inorganic Nitrogen deposition are based on National Atmospheric Deposition Program (NADP) measurements (B. Larsen, U.S. Geological Survey, written. commun., 2007). De-trending methods applied to the year 2002 are described in Alexander and others, 2001. NADP site selection met the following criteria: stations must have records from 1995 to 2002 and have a minimum of 30 observations. The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

46

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Normalized Atmospheric Deposition for 2002, Nitrate (NO3)  

USGS Publications Warehouse

This tabular data set represents the average normalized (wet) deposition, in kilograms per square kilometer multiplied by 100, of Nitrate (NO3) for the year 2002 compiled for every MRB_E2RF1 catchment of the Major River Basins (MRBs, Crawford and others, 2006). Estimates of NO3 deposition are based on National Atmospheric Deposition Program (NADP) measurements (B. Larsen, U.S. Geological Survey, written. commun., 2007). De-trending methods applied to the year 2002 are described in Alexander and others, 2001. NADP site selection met the following criteria: stations must have records from 1995 to 2002 and have a minimum of 30 observations. The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

47

Catchment-scale contaminant transport under changing hydro-climatic conditions in the Aral Sea Drainage Basin, Central Asia  

NASA Astrophysics Data System (ADS)

Dependable projections of future water availability and quality are essential in the management of water resources. Changes in land use, water use and climate can have large impacts on water and contaminant flows across extensive catchments that may contain different administrative regions where shared water resources must be managed. We consider the extensive Aral Sea Drainage Basin (ASDB) and the Amu Darya River Delta in Central Asia, which are currently under severe water stress due to large-scale irrigation expansion. We interpret data on hydro-climatic conditions, main contaminants of surface water and shallow groundwater systems, location of rivers and canal networks, and groundwater flow directions. The data are used together with climate change projections from general circulation models (GCMs) as input to hydrological and (advective) transport modelling. The main goal is to assess how regional transport pathways and travel times have changed, and are likely to change further, in response to past and projected future hydro-climatic changes. More specifically, the hydrological modelling was based on temperature and precipitation change (?T and ?P) results from 65 GCM projections of 21st century conditions (specifically considering time periods around 2025, 2050, and 2100), relative to reference conditions around 1975 (taken from the reference period 1961-1990). Whereas ?T is robustly projected to increase with time, the projected magnitude of ?P differs more among projections for the distant future (2100) than for the near future (2025), with uncertainty remaining even about the direction of change (i.e., positive or negative ?P). However, mainly due to the projected temperature-driven increases in evapotranspiration, ensemble average results show that the Amu Darya river discharge Q in the downstream ASDB is likely to show a decreasing trend throughout the 21st century. Notably, projected changes in the upstream, mountainous regions have a relatively large impact on these Q-projections. For example, the locally created runoff of the downstream region is projected to be maintained or even increase slightly, in contrast to the decreasing Q-trend that reflects an integrated, average response of the entire catchment. A continued drying of surface waters within the Amu Darya river delta implies that advective travel times are increasingly governed by the groundwater system. Such diminished exchanges with surface waters imply increased mean travel times from shallow groundwaters to the (drying) river and drainage canal network by an order of magnitude (from months to years). This can considerably influence mass flow and retention of contaminants in the river delta region, which suffers from e.g. copper, chromium and lead contamination.

Jarsjö, Jerker; Törnqvist, Rebecka; Su, Ye

2013-04-01

48

Properties and development of channel calcretes in a mountain catchment, Tabernas Basin, southeast Spain  

NASA Astrophysics Data System (ADS)

Nonpedogenic channel calcretes of up to 3.5 m thick occur in a number of locations across the Tabernas Basin in Almer?´a Province, southeast Spain. They represent the last major phase of late Quaternary calcium carbonate cementation to affect this semiarid drainage basin. Channel calcretes are situated within the basal parts of sequences of <12-m-thick, poorly sorted, coarse-grained and schist-dominated fluvial gravels that were deposited within confined bedrock channels. Channel calcretes occupy the full basal width of the bedrock channels within which they occur, and mostly crop out near the mouths of tributary valleys to the main Rambla de Tabernas drainage system. Six profiles from five separate channel calcrete outcrops were logged and sampled. All samples were analysed in thin section and under scanning electron microscope (SEM). From these analyses, the macro- and micromorphological properties were identified, and the mode of origin of channel calcrete profiles was assessed. Results indicate that all channel calcretes are massively cemented by calcite and appear uniform at the field profile scale. Microscale analyses reveal that detrital grains within the calcretes are initially coated by micrite, which is overlain by grain-coating and pore-filling sparite. A series of broad trends in cement type and micromorphology are recognised within individual field profiles. All profiles exhibit an increasing degree of calcite crystal size in a down-profile direction. Most field profiles predominantly contain micrite in upper parts with an increasing percentage of sparite towards the base. Some profiles are, however, dominated by sparite and show increasing crystal size and occurrence of euhedral crystals towards the profile base. Many profiles also contain evidence of postcalcite cementation diagenesis in the form of dissolution of calcite crystal faces or replacement of the calcite cement by amorphous silica, with alteration mostly occurring in the lower parts of profiles. The trends within the calcrete fabric appear to have developed in conjunction with a fluctuating water table, with the increased crystal size and occurrence of euhedral crystals towards the base of profiles arising from greater duration of wetting in basal zones. Cementation in some field profiles occurred at depths of up to 12 m within the host sediment, well below the zone of capillary rise and pedogenesis, and in the absence of significant organic activity. As such, channel calcretes in the Tabernas Basin may represent an ideal opportunity to observe the influence of groundwater upon cementation of coarse-grained sediments by carbonate.

Nash, David J.; Smith, Roger F.

2003-02-01

49

Integrating dynamic ecohydrological relations with the catchment response: A multi-scale hydrological modeling effort in a monsoonal regime basin  

NASA Astrophysics Data System (ADS)

Seasonal vegetation changes highly affect the energy and hydrologic fluxes in semiarid regions around the world. Accounting for different water use strategies among drought-deciduous ecosystems is important for understanding how these exploit the temporally brief and localized rainfall pulses of the North American Monsoon (NAM). Furthermore, quantifying these plant-water relations can help elucidate the spatial patterns of ecohydrological processes at catchment scale in the NAM region. In this effort, we focus on the San Miguel river basin (~ 3500 km2) in Sonora, Mexico, which exhibits seasonal vegetation greening that varies across ecosystems organized along mountain fronts. To assess the spatial variability of ecohydrological conditions, we relied on diverse tools that included multi-temporal remote sensing observations, model-based meteorological forcing, ground-based water and energy flux measurements and hydrologic simulations carried out at multiple scales. We evaluated the impact of seasonal vegetation dynamics on evapotranspiration (ET), its partitioning into soil evaporation (E) and plant transpiration (T), as well as their spatiotemporal patterns over the course of the NAM season. We utilized ground observations of soil moisture and evapotranspiration estimated by the eddy covariance method at two sites, as well as inferences of ET partitioning from stable isotope measurements, to test the numerical simulations. We found that ecosystem phenological differences lead to variations in the time to peak in transpiration during a season and in the overall seasonal ratio of transpiration to evapotranspiration (T/ET). A sensitivity analysis of the numerical simulations revealed that vegetation cover and the soil moisure threshold at which stomata close exert strong controls on the seasonal dominance of transpiration or evaporation. The dynamics of ET and its partitioning are then mapped spatially revealing that mountain front ecosystems utilize water differently. The results of this study aid in understanding how variations in water use and phenological strategies affect how soil water is returned to the atmosphere with implications on the watershed runoff response.

Mendez-Barroso, L. A.; Vivoni, E.; Robles-Morua, A.; Yepez, E. A.; Rodriguez, J. C.; Watts, C.; Saiz-Hernandez, J.

2013-05-01

50

Mn-oxides and sequestration of heavy metals in a suburban catchment basin of the Chesapeake Bay watershed  

NASA Astrophysics Data System (ADS)

The Chesapeake Bay is greatly impacted by numerous pollutants including heavy metals and understanding the controls on the distribution of heavy metals in the watershed is critical to mitigation and remediation efforts in controlling this type of pollution. Clasts from a stormwater catchment basin draining a subdivision near George Mason University, Fairfax VA (38°50.090°N 78°19.204°W) were investigated using X-ray diffraction (XRD), Scanning electron microcopy (SEM) and energy dispersive spectroscopy (EDS) to determine the nature of Mn-oxide coatings and relationship to bound heavy metals. Mn-oxides are poorly crystalline and occur as subhedral to anhedral platy particles and more rarely as euhedral plates. Micronodules are a commonly observed texture. Chemical compositions of coatings are variable with average major constituent concentrations being Mn (33.38 wt%), Fe (11.88 wt%), Si (7.33 wt%), Al (5.03 wt%), and Ba (0.90 wt%). Heavy metals are found in the coatings with Zn being most prevalent, occurring in approximately 58% of analyses with an average concentration of (0.66 wt%). Minor amounts of Co, Ni, Pb, and Cl are observed. Heavy metals and Cl are interpreted as being derived from road pollution. Mn-oxides can serve as a sequestration mechanism for pollution but may also release heavy metals. Field and laboratory observations indicate Mn-oxides occurring on the surface of the clasts can be mechanically mobilized. This is a mechanism for transporting heavy metals into the Chesapeake Bay watershed. Deicing agents may serve as a mechanism to release heavy metals through cation exchange and increased ionic strength. This is the first detailed mineralogical investigation of Mn-oxides and the roles they may play in pollution in the Chesapeake Bay.

Adams, James P.; Kirst, Robert; Kearns, Lance E.; Krekeler, Mark P. S.

2009-09-01

51

Hydrological control on the triggering of debris flows in alpine catchments: storm analysis and basin response variability  

NASA Astrophysics Data System (ADS)

Three storm events, occurred in 2006, 2007 and 2009 in the upper Adige River basin (Eastern Alps, northern Italy) have been analyzed. The first storm system (4 October 2006) generated a flash flood with almost no debris flows and landslides, the second (21 June 2007) triggered a large number of debris flows and was characterized by a relatively minor runoff response, and the third (4 September 2009) resulted in both a relevant flash flood response and debris flows in minor streams. A strong interest both for civil protection and research purposes has been devoted by local authorities and researchers to such events. The study methods include radar rainfall analysis, hydrological modeling and GIS processing of spatial rainfall data and debris-flow locations. Precise information on debris-flow location and related volumes were derived from a geo-spatial database of instability phenomena implemented and managed by the Autonomous Province of Bolzano. Patterns of rainfall distribution and relations between the main hydrological variables (cumulative rainfall, intensity and antecedent moisture) have been analyzed to explain differences in catchments responses between the three studied events. Radar rainfall data have permitted to analyze rainfall fields with high spatial resolution, taking into account also the elevation variability of rainfall rates. The striking responses' contrast among the three events is related to differences in antecedent moisture, space-time structure of the rainstorms, cumulative rainfall and intensity distributions and temperature regime. The frequency analysis of the main hydrological variables revealed to be a powerful tool capable of distinguishing, within a synoptic framework, the space-time-magnitude variability of the events, so as to highlight the differences in flood and debris-flow response.

Crema, Stefano; Marchi, Lorenzo; Marra, Francesco

2013-04-01

52

Lacustrine groundwater discharge (LGD) to a closed- basin lake - a concept for estimating the effects of a changing catchment on the lake water balance  

NASA Astrophysics Data System (ADS)

In the water balance of closed-basin lakes, which are common in young glacial landscapes of the North German Plains, groundwater is an important term beside precipitation and evaporation. A quantification of groundwater impacts on the lake water balance is still a challenge although there is a broad spectrum of methods from point measurements over integrative methods to numerical modelling approaches. All modelling approaches rely on a fixed lake catchment. This might be an adequate assumption for steady state estimations and catchments in hilly and mountainous landscapes but it is not for the long run in flat terrain such as the North German Plains. Of course, the calculation of the temporal development of a water balance requires the availability of time series of groundwater levels and lake water stages. Such hydraulic data set covering more than 50 years with a monthly resolution is available for the Lake Stechlin area. A former study already pointed out that the lake catchment differs between wet an dry years, but in that study no estimation of the water balance was conducted. We present a three dimensional conceptual model, which is based on the time series of the hydraulic data, additional geological and geomorphological information as well as estimations of spatial and temporal groundwater recharge rates within the area. At first, a geological model is established on the basis of about 50 drill logs. Based on hydraulic head data the temporal development of the catchment size is determined and the maximum and minimum area for groundwater exfiltration into the lake and surface water infiltration into the aquifer are derived. In the end, the annual varying catchment size is combined to the annual varying groundwater recharge to get an annual "steady state" estimation of the lake water balance. This model is the basis for further numerical modelling.

Pöschke, Franziska; Lewandowski, Jörg; Nützmann, Gunnar

2014-05-01

53

How accurately are climatological characteristics and surface water and energy balances represented for the Colombian Caribbean Catchment Basin?  

NASA Astrophysics Data System (ADS)

In Colombia, the access to climate related observational data is restricted and their quantity is limited. But information about the current climate is fundamental for studies on present and future climate changes and their impacts. In this respect, this information is especially important over the Colombian Caribbean Catchment Basin (CCCB) that comprises over 80 % of the population of Colombia and produces about 85 % of its GDP. Consequently, an ensemble of several datasets has been evaluated and compared with respect to their capability to represent the climate over the CCCB. The comparison includes observations, reconstructed data (CPC, Delaware), reanalyses (ERA-40, NCEP/NCAR), and simulated data produced with the regional climate model REMO. The capabilities to represent the average annual state, the seasonal cycle, and the interannual variability are investigated. The analyses focus on surface air temperature and precipitation as well as on surface water and energy balances. On one hand the CCCB characteristics poses some difficulties to the datasets as the CCCB includes a mountainous region with three mountain ranges, where the dynamical core of models and model parameterizations can fail. On the other hand, it has the most dense network of stations, with the longest records, in the country. The results can be summarised as follows: all of the datasets demonstrate a cold bias in the average temperature of CCCB. However, the variability of the average temperature of CCCB is most poorly represented by the NCEP/NCAR dataset. The average precipitation in CCCB is overestimated by all datasets. For the ERA-40, NCEP/NCAR, and REMO datasets, the amplitude of the annual cycle is extremely high. The variability of the average precipitation in CCCB is better represented by the reconstructed data of CPC and Delaware, as well as by NCEP/NCAR. Regarding the capability to represent the spatial behaviour of CCCB, temperature is better represented by Delaware and REMO, while precipitation is better represented by Delaware. Among the three datasets that permit an analysis of surface water and energy balances (REMO, ERA-40, and NCEP/NCAR), REMO best demonstrates the closure property of the surface water balance within the basin, while NCEP/NCAR does not demonstrate this property well. The three datasets represent the energy balance fairly well, although some inconsistencies were found in the individual balance components for NCEP/NCAR.

Hoyos, Isabel; Baquero-Bernal, Astrid; Hagemann, Stefan

2013-09-01

54

Preliminary stratigraphic and paleomagnetic results from Neogene basins across the Anatolian Plateau (Turkey).  

NASA Astrophysics Data System (ADS)

An integrated paleomagnetic and stratigraphic study on Neogene basins across the Anatolian Plateau was carried out. This study is developed within the VAMP (Vertical Anatolian Movement Project), an interdisciplinary project aimed to the recent tectonic evolution of the central Anatolian Plateau. The studied areas are located in southern Turkey (Adana, Mut and Ermenek basins) and in northern Turkey (Kazan, Çankiri, Kastamonu, Boyabat and Sinop basins). For paleomagnetic analyses we sampled 1062 standard cylindrical samples from 13 stratigraphic sections, and 746 samples for paleontological analysis were taken from the same sections. AMS (Anisotropy of Magnetic Susceptibility), magnetic mineralogy and paleomagnetic polarity data are presented together with the results of the integrated stratigraphic analyses. In the Southern Turkey basins preliminary results show the diffuse presence of authigenic iron sulphides, together with magnetite, as main magnetic carriers. In these sections the iron-sulphides Characteristic Natural Magnetization (ChRM) component is characterized by inconsistent polarity record, suggesting that iron-sulphides have a late diagenetic origin. Conversely, magnetite bearing sediments show more reliable results in term of magnetic polarity interpretations. Preliminary stratigraphic and paleomagnetic results from the southern margin of the plateau allow us both to refine the stratigraphy for the late Miocene of the Adana Basin and to better constrain the age of the youngest marine deposits of the Mut and Ermenek basins. In the late Miocene of the Adana Basin evidence of the Messinian salinity crisis led to a new stratigraphic framework specially for the Messinian-Pliocene interval. Thick fluvial conglomerates from the uppermost Messinian deposits of the Adana Basin, which could be linked to the activation of the southern margin of the plateau, allow us to constrain at about 5.4 Ma the uplift of the central Anatolian Plateau. On the other hand, the preliminary results of the micropaleontological analyses carried out on the higher marine deposits sampled in the northern part of the Ermenek Basin (Basyayla section, 1840 m a.s.l.) point to a post-Tortonian age for the plateau uplift. The age of the basins at the northern margin of the plateau are very poor constrained, except for that basins containing vertebrate-bearing continental deposits. However, from a palaeogeographic point of view, our preliminary data suggest a possible Tortonian connection between the Çankiri Basin and the Paratethyan realm. This presentation was supported by the EUROCORE programme TOPO-EUROPE of the European Science Foundation.

Lucifora, Stella; Cifelli, Francesca; Mazzini, Ilaria; Cosentino, Domenico; Mattei, Massimo; Cipollari, Paola; Gliozzi, Elsa; Palolo Cavinato, Gian

2010-05-01

55

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: NLCD 2001 Tree Canopy  

USGS Publications Warehouse

This tabular data set represents the mean percent tree canopy from the Canopy Layer of the National Land Cover Dataset 2001 (LaMotte and Wieczorek, 2010), compiled for every MRB_E2RF1 catchment of Major River Basins (MRBs, Crawford and others, 2006). The source data set represents tree canopy percentage for the conterminous United States for 2001. The Canopy Layer of the National Land Cover Data Set for 2001 was produced through a cooperative project conducted by the Multi-Resolution Land Characteristics (MRLC) Consortium. The MRLC Consortium is a partnership of Federal agencies (http://www.mrlc.gov), consisting of the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration (NOAA), the U.S. Environmental Protection Agency (USEPA), the U.S. Department of Agriculture (USDA), the U.S. Forest Service (USFS), the National Park Service (NPS), the U.S. Fish and Wildlife Service (USFWS), the Bureau of Land Management (BLM), and the USDA Natural Resources Conservation Service (NRCS). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte; Andrew E.

2010-01-01

56

Analysis of Cheshire basin by gravity method: Some preliminary results  

NASA Astrophysics Data System (ADS)

Gravity data acquired from Cheshire basin located in the northwestern part of the United Kingdom were processed and analysed to determine the structural pattern within the entire sedimentary basin. A total of 753 gravity data were obtained from the British Geological Society and with the aid of Oasis Montaj software, maps of Bouguer anomaly, isostatic and total horizontal derivative were obtained for qualitative and quantitative interpretation in determining the fault trend and the tectonic system of the study area. The positive Bouguer anomaly region found in the northwest of the study area is associated with the high density sedimentary rocks while the negative region in the southern part corresponds to low density sediments. The regional and local isostatic maps with different cut-off wavelengths reflect changes in anomalies corresponding to different types of sedimentary rocks. The general trends of faults in the Chesire basin are shown in the total horizontal derivative map of the Bouguer gravity values. Most of the major faults found in the southern part of the study area are trending in NW-SE and NE-SW directions. The less dominant faults are found in the western and eastern parts with N-S trending faults while in the northern and southern part are trending E-W. The 2D modeling shows the estimated depth to limestone basement of about 3736 m below the sandstone and mudstone.

Shafie, Nadiah Hanim; Hamzah, Umar; Samsudin, Abdul Rahim

2014-09-01

57

Late Miocene uplift of the NE Tibetan Plateau inferred from basin filling, planation and fluvial terraces in the Huang Shui catchment  

NASA Astrophysics Data System (ADS)

The geomorphological evolution of the marginal areas of the Tibetan Plateau may provide valuable information for reconstructing the tectonic movements of the region. This study reports on a morpho-tectonic analysis of the Huang Shui catchment (tributary of the Yellow River), in the Northeastern Tibetan Plateau using a digital elevation model and field observations. One prominent bevelled surface, preliminarily interpreted as a peneplain surface, is recognized at around 2750 m altitude. It corresponds with the top of the relict sedimentary fill of large tectonic basins, and the adjacent summits. After the formation of this peneplain, a terrace sequence was formed along the Huang Shui river. The transition of peneplain surface formation to incision was dated as older than 10-6 Ma using the biochronology of micromammalian assemblages from fluvial terraces and the depositional record of the basin fill. The river incision into the former peneplain is attributed to an important uplift event around 10-17 Ma.

Wang, Xianyan; Lu, Huayu; Vandenberghe, Jef; Zheng, Shaohua; van Balen, Ronald

2012-05-01

58

Effects of catchment and riparian landscape setting on water chemistry and seasonal evolution of water quality in the upper Han River basin, China.  

PubMed

Six-year (2005-2010) evolution of water chemistry (Cl(-), NO(3)(-), SO(4)(2-), HCO(3)(-), Na(+), K(+), Ca(2+) and Mg(2+)) and their interactions with morphological properties (i.e., slope and area), land cover, and hydrological seasonality were examined to identify controlling factors and processes governing patterns of stream water quality in the upper Han River, China. Correlation analysis and stepwise multiple regression models revealed significant correlations between ions (i.e., Cl(-), SO(4)(2-), Na(+) and K(+)) and land cover (i.e., vegetation and bare land) over the entire catchment in both high- and low-flow periods, and in the buffer zone the correlation was much more stronger in the low-flow period. Catchment with steeper slope (>15°) was negatively correlated with major ions, largely due to multicollinearity of basin characteristics. Land cover within the buffer zone explained slightly less of major elements than at catchment scale in the rainy season, whereas in the dry season, land cover along the river networks in particular this within 100 m riparian zone much better explained major elements rather than this over the entire catchment. Anthropogenic land uses (i.e., urban and agriculture) however could not explain water chemical variables, albeit EC, TDS, anthropogenic markers (Cl(-), NO(3)(-), SO(4)(2)), Na(+), K(+) and Ca(2+) significantly increased during 2005-2010, which was corroborated by principal component analyses (PCA) that indicated anthropogenic inputs. Observations demonstrated much higher solute concentrations in the industrial-polluted river. Our results suggested that seasonal evolution of water quality in combined with spatial analysis at multiple scales should be a vital part of identifying the controls on spatio-temporal patterns of water quality. PMID:23349700

Li, Siyue; Xia, Xiaoling; Tan, Xiang; Zhang, Quanfa

2013-01-01

59

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: 30-Year Average Daily Minimum Temperature, 1971-2000  

USGS Publications Warehouse

(MRBs, Crawford and others, 2006). The source data were the United States Average Monthly or Annual Minimum Temperature, 1971 - 2000 raster data set produced by the PRISM Group at Oregon State University. The MRB_E2RF1 catchments are based on a modified version of the Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

60

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Artificial Drainage (1992) and Irrigation (1997)  

USGS Publications Warehouse

This tabular data set represents the estimated area of artifical drainage for the year 1992 and irrigation types for the year 1997 compiled for every MRB_E2RF1 catchment of Major River Basins (MRBs, Crawford and others, 2006). The source data sets were derived from tabular National Resource Inventory (NRI) data sets created by the National Resources Conservation Service (NRCS, U.S. Department of Agriculture, 1995, 2000). Artificial drainage is defined as subsurface drains and ditches. Irrigation types are defined as gravity and pressure. Subsurface drains are described as conduits, such as corrugated plastic tubing, tile, or pipe, installed beneath the ground surface to collect and/or convey drainage. Surface drainage field ditches are described as graded ditches for collecting excess water. Gravity irrigation source is described as irrigation delivered to the farm and/or field by canals or pipelines open to the atmosphere; and water is distributed by the force of gravity down the field by: (1) A surface irrigation system (border, basin, furrow, corrugation, wild flooding, etc.) or (2) Sub-surface irrigation pipelines or ditches. Pressure irrigation source is described as irrigation delivered to the farm and/or field in pump or elevation-induced pressure pipelines, and water is distributed across the field by: (1) Sprinkle irrigation (center pivot, linear move, traveling gun, side roll, hand move, big gun, or fixed set sprinklers), or (2) Micro irrigation (drip emitters, continuous tube bubblers, micro spray or micro sprinklers). NRI data do not include Federal lands and are thus excluded from this dataset. The tabular data for drainage were spatially apportioned to the National Land Cover Dataset (NLCD, Kerie Hitt, U.S. Geological Survey, written commun., 2005) and the tabular data for irrigation were spatially apportioned to an enhanced version of the National Land Cover Dataset (NLCDe, Nakagaki and others, 2007). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

61

Las Vegas Basin Seismic Response Project: Preliminary Results From Seismic Refraction Experiments, Las Vegas, NV.  

NASA Astrophysics Data System (ADS)

In May and September 2002, seismic refraction data were acquired in the Las Vegas basin. Located in the southern Basin and Range province, the cities of Las Vegas, North Las Vegas, and Henderson sit atop a fault-bounded basin with a depth of up to 5 km and basin dimensions of roughly 60 km wide (east-west) by 50 km in length (north-south). Previous isostatic gravity, seismic reflection, and aeromagnetic studies indicate that a series of sub-basins exist beneath the unconsolidated basin fill, with the deepest sub-basin occurring 5 km west of the fault block bounding the eastern edge of the basin (Frenchman Mountain). The basin is significantly deeper along its northern extremity, following the path of the fault block bounding the northern edge of the basin (Las Vegas Valley Shear Zone), and along the western edge of Frenchman Mountain. Recent, paleoseismic studies have indicated that faults in the Las Vegas region have the potential for an earthquake of M6.5 to 7.0. It is estimated that a M6.9 earthquake in the basin could produce about 11 billion dollars in damage and a significant number of deaths and/or injuries. In addition, an equivalent or larger event in the Death Valley fault zone, 150 km distance, would also be devastating to the metropolitan area of approximately 1.5 million residents. Therefore, it is essential to understand the seismic hazard posed to the Las Vegas region. This project is part of a larger collaborative effort to characterize the basin and its response to ground shaking. The University of Nevada, Las Vegas with assistance from the University of Texas at El Paso, students from UNLV and UTEP, volunteers from the community and several students from Centennial High school deployed 432 portable seismic recorders ("Texans") throughout the valley. Shot point locations were located at three quarries in the valley, one to the north, one to the east and one to the southwest. The profiles cross the Las Vegas Valley Shear zone as well as a prominent NW/SE trending step in the basin floor across which the basement drops from 2 to 4 km in depth. In addition, the profiles cross several Quaternary fault scarps, which have recently been identified as tectonic in origin. Preliminary analyses of the seismic refraction data indicate that the basin has an average P-wave velocity of 4.5 km/s and is in agreement with the estimated basin depths from isostatic gravity studies (2 to 5 km depth). Both tomographic inversion and forward modeling techniques are being used to analyze these data. These data will be used to produce a velocity model of the basin and image the basin/bedrock contact. In addition, these data will be integrated into a community model, which is being produced by the Las Vegas Basin Seismic Response working group to further assess the site response of the basin.

Zaragoza, S. A.; Snelson, C. M.; Harder, S. H.; Kaip, G.; Luke, B.; Buck, B. J.; Hanson, A. D.

2002-12-01

62

REACH-ER: a tool to evaluate river basin remediation measures for contaminants at the catchment scale  

Microsoft Academic Search

The European Union (EU) adopted the Water Framework Directive (WFD) in 2000 ensuring that all aquatic ecosystems meet `good status' by 2015. However, it is a major challenge for river basin managers to meet this requirement in river basins with a high population density as well as intensive agricultural and industrial activities. The EU financed AQUAREHAB project (FP7) specifically examines

Ann van Griensven; Pieter Jan Haest; Steven Broekx; Piet Seuntjens; Paul Campling; Geraldine Ducos; Ludek Blaha; Jaroslav Slobodnik

2010-01-01

63

SUGAR CANE GROWING AND CATTLE GRAZING AS DRIVERS TO WETLAND DEGRADATION IN UGANDA: A case of upper river Ruizi and Iguluibi catchments Lake Victoria basin  

NASA Astrophysics Data System (ADS)

Introduction: This study was conducted with in the framework of the VLIR-OI project with the aim of making contributions to the Diagnosis and Remediation of Land Degradation Processes in the Riparian Zone of Lake Victoria Uganda in view of reducing sediment pollution of the Lake Waters with a special focus on the upper river Ruiz and Iguluibi catchments. The study seeks to investigate Sugarcane growing and cattle grazing as drivers to wetland degradation in light of the current farming systems and practices and their contributions to land degradation and pollution of the Lake Victoria waters. Vegetation especially wetlands improves the resistance to erosion. The removal of riparian vegetation tends to accelerate surface erosion as a result of human activities. Increased erosion with in the catchments due to clearing of wetlands for sugarcane growing and cattle grazing has caused adverse increased sedimentation, degraded the water quality, and reduced the water productivity of the Lake Victoria Basin. Methods: We conducted a qualitative and quantitative study to investigate Sugarcane growing and cattle grazing as drivers to wetland degradation in Uganda in light of the current farming systems and practices and their socio-economic contributions to wetland degradation and pollution of the Lake Victoria waters. Focus group discussions, key informant interviews, semi structured interviews and observations were undertaken with the relevant stakeholders in the community. Results: Findings reveal that in Iguluibi catchment, sugarcane growing is now a major activity indicating land use change since the 1990s. Community members said when planting sugarcane all vegetations including all trees are cut leaving the land bare to allow the tractor to clear the land for cultivation. This has left the land bare without any natural vegetation with increased erosion hence eventually loss of soil fertility and increased sediment pollution to the Lake Victoria waters. As a result of land loosing fertility upland, due to erosion and runoff, most community members have resorted to wetlands for agricultural practices with in the catchment and this has hardly left any natural vegetation to protect the soil and increased runoff to Lake Victoria hence sediment pollution of the lake waters. In the Ruizi catchment, many valleys, the natural vegetation has been cut and the land has been turned into pastureland. The massive expansion of livestock keeping into the low lands mainly covered by wetlands is relatively new (over the last 20 years). Burning of rangelands is a common practice and seasonal swamps are grazed during the dry season This change of land use as far as farming practice is concerned has had a big impact on the water levels of the River Ruizi systems in a number of ways for example: the wetland filter system for sediments and sediment fixed nutrients is compromised; lowering of the water storage capacity of the papyrus swamps as a consequence of drainage, hence surface lowering; river bank erosion of the Ruizi by livestock coming into the river for drinking; pollution of the River Ruizi by livestock defecating into the water while drinking. Due to overstocking of the steep slopes by livestock, the low lands are overgrazed which has resulted in soil erosion, that is, mainly sheet and rill erosion, mass movement below cattle tracks, and stone movement by cattle trampling. The steep slope grazing area has generated substantial runoff, the concentrated flow of which causes gullies that cut through the banana groves. Conclusion Vegetation management of riparian areas especially wetlands in Uganda should conserve and maintain adequate ecological balance of the Lake by reducing on nutrient-loaded fluxes from the riparian zone into the Lake Victoria basin.

Nakiyemba Were, Alice; Isabirye, Moses; Mathijs, Erik; Deckers, Jozef; Poesen, Jean

2010-05-01

64

SPATIAL VARIABILITY OF DRY SPELLS A spatial and temporal rainfall analysis of the Pangani basin and Makanya catchment, Tanzania  

NASA Astrophysics Data System (ADS)

Rainfall and soil moisture are key parameters for food production and which are spatial and temporal variable. In a ever growing world the stress on water for food production increases. Farmers especially in semi arid regions with rain fed agriculture are more often forced to make away from "A" locations where water is available to water scares "B" or worse locations. Obliged by availability of arable land, tradition, customs, natural 6th sense or farmers cleverness. To improve agricultural yields a better water resource planning ,supported by system knowledge, is needed. This study describes a Markov bases dry spell tool which can fulfil in this need. By making use of Markov properties of rainfall, the temporal variability has been analysed. Plotting the derived seasonal transition probabilities vs. the rainfall amount a spatial variable power function could be derived. The spatial and temporal knowledge of rainfall was combined in the Markov based dry spell tool. For a given probability the tool provides a dry spell map. The dry spell tool is a powerful tool to assess vulnerability of dry spells based on meteorological data. The meteorological dry spell in combination with the agricultural dry spell length or critical dry spell length, which is determined by soil and vegetation characteristics, risk maps of an area to the vulnerability of dry spells could be made. The tool was applied in a case study in the Makanya catchment and showed: Compared to the lower middle part of the catchment, high altitude parts of the catchment receive higher amounts of rainfall, have shorter meteorological dry spells and are more resilient to dry spells due to their soil and vegetation characteristics. As a result one can state that farmers living in mountainous areas are blessed by their location. They receive more rain and have lower probability of long dry spells, higher probability of crop success and a higher probability of high yields, in contrast to the farmers in the valley. However, the latter have a chance at making a living as well. The opportunity is, next to the more traditional water management strategies (improving irrigation etc.), to develop new water management strategies (rainwater harvesting, improvement of soil characteristics and decrease of transpiration fluxes) to bridge or decrease the vulnerability of meteorological dry spells.

Fischer, B. M. C.; Savenije, H. H. G. H. H. G.

2009-04-01

65

Impacts of climate change on the seasonality of low flows in 134 catchments in the River Rhine basin using an ensemble of bias-corrected regional climate simulations  

NASA Astrophysics Data System (ADS)

The impacts of climate change on the seasonality of low flows were analysed for 134 sub-catchments covering the River Rhine basin upstream of the Dutch-German border. Three seasonality indices for low flows were estimated, namely the seasonality ratio (SR), weighted mean occurrence day (WMOD) and weighted persistence (WP). These indices are related to the discharge regime, timing and variability in timing of low flow events respectively. The three indices were estimated from: (1) observed low flows; (2) simulated low flows by the semi-distributed HBV model using observed climate as input; (3) simulated low flows using simulated inputs from seven combinations of General Circulation Models (GCMs) and Regional Climate Models (RCMs) for the current climate (1964-2007); (4) simulated low flows using simulated inputs from seven combinations of GCMs and RCMs for the future climate (2063-2098) including three different greenhouse gas emission scenarios. These four cases were compared to assess the effects of the hydrological model, forcing by different climate models and different emission scenarios on the three indices. Significant differences were found between cases 1 and 2. For instance, the HBV model is prone to overestimate SR and to underestimate WP and simulates very late WMODs compared to the estimated WMODs using observed discharges. Comparing the results of cases 2 and 3, the smallest difference was found for the SR index, whereas large differences were found for the WMOD and WP indices for the current climate. Finally, comparing the results of cases 3 and 4, we found that SR decreases substantially by 2063-2098 in all seven sub-basins of the River Rhine. The lower values of SR for the future climate indicate a shift from winter low flows (SR > 1) to summer low flows (SR < 1) in the two Alpine sub-basins. The WMODs of low flows tend to be earlier than for the current climate in all sub-basins except for the Middle Rhine and Lower Rhine sub-basins. The WP values are slightly larger, showing that the predictability of low flow events increases as the variability in timing decreases for the future climate. From comparison of the error sources evaluated in this study, it is obvious that different RCMs/GCMs have a larger influence on the timing of low flows than different emission scenarios. Finally, this study complements recent analyses of an international project (Rhineblick) by analysing the seasonality aspects of low flows and extends the scope further to understand the effects of hydrological model errors and climate change on three important low flow seasonality properties: regime, timing and persistence.

Demirel, M. C.; Booij, M. J.; Hoekstra, A. Y.

2013-10-01

66

Stable Water Isotope Tracing and Model Evaluation in Large Basins: the `` Special Case'' of Semi-Arid Catchments  

Microsoft Academic Search

The use of stable water isotopes in hydro-climate monitoring and modelling offers a new means of measuring and parameterizing critical processes. Here we review these specifically for the case of semi-arid basins where water resources are essential for potable supply and agriculture around the world. The verity and performance of existing models is examined using observations and simulations of stable

A. Henderson-Sellers; P. Airey; K. McGuffie; J. Bradd; D. Stone

2004-01-01

67

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Nutrient Application (Phosphorus and Nitrogen) for Fertilizer and Manure Applied to Crops (Cropsplit), 2002  

USGS Publications Warehouse

This tabular data set represents the estimated amount of phosphorus and nitrogen fertilizers applied to selected crops for the year 2002, compiled for every MRB_E2RF1 catchment of Major River Basins (MRBs, Crawford and others, 2006). The source data set is based on 2002 fertilizer data (Ruddy and others, 2006) and tabulated by crop type per county (Alexander and others, 2007). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for MRB_E2RF1 catchments for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

68

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Nutrient Inputs from Fertilizer and Manure, Nitrogen and Phosphorus (N&P), 2002  

USGS Publications Warehouse

This tabular data set represents the total amount of nitrogen and phosphorus, in kilograms for the year 2002, compiled for every MRB_E2RF1 catchment of the Major River Basins (MRBs, Crawford and others, 2006). The source data set is County-Level Estimates of Nutrient Inputs to the Land Surface of the Conterminous United States, 1982-2001 (Ruddy and others, 2006). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

69

Preliminary assessment of channel stability and bed-material transport in the Coquille River basin, southwestern Oregon  

USGS Publications Warehouse

This report summarizes a preliminary study of bed-material transport, vertical and lateral channel changes, and existing datasets for the Coquille River basin, which encompasses 2,745 km2 (square kilometers) of the southwestern Oregon coast. This study, conducted to inform permitting decisions regarding instream gravel mining, revealed that:

Jones, Krista L.; O'Connor, Jim E.; Keith, Mackenzie K.; Mangano, Joseph F.; Wallick, J. Rose

2012-01-01

70

Quantification of water and sediment yield from small catchment in open mining areas: experience and results from Poro nickel mining basin in New Caledonia  

NASA Astrophysics Data System (ADS)

Water management in mining environments is a major challenge of the mining projects. In New Caledonia large areas have been excavated for Nickel mining since the end of the 19th century. In the past, the bad management of the water and coarse sediments left scars in the landscape and management problems in the channel reaches downstream. Nowadays, open mining techniques no longer yield coarse material out of the mining areas but the management of water and fine sediment remains a difficult question as the suspended sediments reach the very fragile environment of the lagoon. In addition, in many areas, it threatens human activities in the downstream rivers. In order to quantify and understand the formation of runoff, erosion and sediment transport in small mining watersheds the "Hydromine" project was initiated in 2008 by the New Caledonia government (DAVAR) with the collaboration of the University of New Caledonia (UNC) and later with the scientific support of Irstea Grenoble. The questions addressed by this project are: - What is the response (water and sediments) of a mining watershed to a rainfall input? - What factors control this response? - What are the processes involved? And which are dominant in the various hydrometeorological situations? - What are the characteristics of the transported materials? - What is the efficiency of mitigation works in the mining area? Two small embedded catchments (0.09 and 0.30 km²) are monitored for measuring rainfall, runoff and fine sediment transport in the mining area of Poro, East cost of New Caledonia. Elevation ranges from 197 to 366 m.a.s.l. The slope are steep (36 % in average but locally up to 130%) and the vegetation cover is very low (20% for the larger basin, 0% for the headwater basin). Rainfall-runoff and discharge-sediment concentration (SSC) relationship were analysed at the event and annual time scale. As a result, we pointed out the main factors that influence the response of the basins to a rainfall event: rainfall depth, rainfall intensity in fifteen minutes and in two hours, peak discharge, runoff coefficient, dry time duration before the event and flood duration. The calculation of suspended sediment yield (SSY) at different time scales gives an evaluation of the pollution delivered to the creeks and lagoon and of the water management and sediment trap efficiency. An extreme rainfall event (December 25th, 2011) of 500 mm in 26 hours yielded downstream more suspended sediment than all the floods of the previous monitored period. This highlights the threshold effects in runoff and erosion response in these open mining areas.

Mathys, Nicolle; Allenbach, Michel; Wottling, Geoffroy; Carpentier, Laureen; Freydier, Perrine; Navarrot, Lucie

2014-05-01

71

Congo Basin Streamflow characterization using multi-source satellite-derived data: Preliminary Results  

NASA Astrophysics Data System (ADS)

The Congo Basin in Central Africa has the second largest discharge of any river system, second only to the Amazon Basin. As such, it is considered a potential and strategic asset for supplying not only fresh water but also clean energy through hydropower generation. However, very little of Congo River Basin hydrology is known. Indeed, the basin hydrometeorological network is deteriorating and has a small number of gauges unevenly distributed throughout the Congo watershed. In such cases where in situ data are scarce, remote sensing can be used to quantify rainfall pattern and river flow regime. In default of contributing to quantification exercises, limited ground data available can be used for validation work. To better understand hydrological processes in the Congo River Basin, a 2009 NASA funded project entitled “Hydrological Response to Land Cover and Land Use Change in the Congo Basin” exploits remote sensing capabilities coupled with large scale hydrological modeling. Temporal and terrestrial satellite-based data are ingested into the USGS Geospatial Streamflow Model (GeoSFM) for daily flow generation. The reliance on remotely sensed data to replace or supplement ground data for this hydrological application necessitates rigorous validation of these products. As TRMM Satellite rainfall estimates are being used in this study in place of gauge observations, ground precipitation data reported in existing nationally-held datasets from 33 meteorological stations are used for validation purposes. Initial research on the Congo Basin compared streamflow estimated with GeoSFM against available current and historical streamflow data. While initial results were promising, some discrepancies were revealed, attributed to the accuracy of the input data and the non-calibration of the model. A key finding was that the existing parameterization of land cover using coarse resolution data is inadequate to accurately characterize rainfall-runoff processes in the Congo. As part of the NASA project, the important question of improving the agreement between modeled flows from satellite-derived data and observed flow data from hydrometric field stations is addressed. To evaluate the GeoSFM performance, the model is run using coarse resolution (Land Cover Land Use) LCLU and DEM inputs and then using improved region-specific high spatial resolution inputs. Intercomparisons are made to evaluate improvement to streamflow characterization based on improved input data. Improved streamflow is a key for establishing the setting for a high-performance calibration process for the Congo. Changing the parameter values used in the model until a satisfactory agreement between simulated and the recorded variables is obtained is an integral part of modeling. However, in order to produce realistic parameters values and a sufficiently calibrated model, the calibration requires the finest baseline simulated streamflow data possible. A poster will present our preliminary results.

Munzimi, Y.; Hansen, M. C.; Asante, K. O.

2010-12-01

72

Preliminary study on soil to rock spectral ratio method of microtremor measurement in Taipei Basin, Taiwan  

NASA Astrophysics Data System (ADS)

Taipei city is the capital of Taiwan which located in Taipei basin and covered with hundreds meter of alluvial layer that might cause serious damage during huge earthquake. Prediction of possible strong motion levels occurred in the basin then became popular. Engineers most like to use Ground Motion Prediction Equation (GMPEs) as common tool for seismic hazard calculation but GMPEs were usually debated that it can only give one prediction value (PGA, PGV, Sa etc.) rather than time history or spectrum. Seismologists tried theoretical simulation (1D, 2D, 3D method) but could only give low frequency (usually less than 1 Hz) results restricted to that the shallow structures were not clear enough. Resent years, wide frequency simulation techniques such as empirical green's function added stochastic simulation method (hybrid method) were applied to several different purposes but site effect still plays an important role that need to be considered. Traditionally soil to rock spectral ratio of shear wave (denoted as S/R) was widely applied to check basin effect for decades but the technique needs lots of permanent stations and several years to get enough records. If some site located within strong motion network but not close enough to the strong motion stations, interpolate or extrapolate results needed to be used. Wen and Huang (2012) conducted a dense microtremor measurement network in whole Taiwan and applied microtremor H/V to discuss dominant frequency with traditional transfer functions from earthquake shear wave and found good agreement between them. Furthermore, in this study, the ability of soil to rock spectral ratio of microtremor (denoted as MS/R) measurement was tested in Taipei basin. The preliminary results showed MS/R had good agreement with S/R between 0.2 to 5 Hz. And distance from soil site to reference rock site should no greater than 8 to 10 km base on degree of spectrum difference (DSPD) calculation. If the MS/R works that site effect study from this technique could be applied for some region which distribution of strong motion stations were not dense enough after all.

Huang, Jyun Yan; Wen, Kuo Liang; Te Chen, Chun; Chang, Shun Chiang

2014-05-01

73

Large-scale single incised valley from a small catchment basin on the western Adriatic margin (central Mediterranean Sea)  

NASA Astrophysics Data System (ADS)

The Manfredonia Incised Valley (MIV) is a huge erosional feature buried below the Apulian shelf, on the western side of the Adriatic margin. The incision extends more than 60 km eastward, from the Tavoliere Plain to the outer shelf, not reaching the shelf edge. High-resolution chirp sonar profiles allow reconstruction of the morphology of the incision and its correlation at regional scale. The MIV records a single episode of incision, induced by the last glacial-interglacial sea level fall that forced the rivers draining the Tavoliere Plain to advance basinward, reaching their maximum extent at the peak of the Last Glacial Maximum. The valley was filled during a relatively short interval of about 10,000 yr during the Late Pleistocene-Holocene sea level rise and almost leveled-off at the time of maximum marine ingression, possibly recording the short-term climatic fluctuations that occurred. The accommodation space generated by the lowstand incision was exploited during the following interval of sea level rise by very high rates of sediment supply that allowed the preservation of up to 45 m of valley fill. High-resolution chirp sonar profiles highlight stratal geometries that are consistent with a typical transgressive valley fill of an estuary environment, including bay-head deltas, central basin and distal barrier-island deposits, organized in a backstepping configuration. The highest complexity of the valley fill is reached in the shallowest and most proximal area, where a kilometric prograding wedge formed during a period dominated by riverine input, possibly connected to high precipitation rates. Based on the depth of the valley margins during this interval, the fill was likely isochronous with the formation of sapropel S1 in the Mediterranean region and may have recorded significant fluctuations within the hydrological cycle.

Maselli, Vittorio; Trincardi, Fabio

2013-01-01

74

The effects of soil properties on the turbidity of catchment soils from the Yongdam dam basin in Korea.  

PubMed

Environmental concerns have been raised that suspended solids in turbid water adversely affect human health, and that their removal increases in the cost of water treatment. The Yongdam dam reservoir, located in the southwestern region of Korea, is severely affected by inflowing turbid water after storms. In this study, soil samples were collected from 37 sites in the Yongdam upstream basin to investigate mineralogical and environmental factors associated with the turbidity potential of soils in water environments. Turbidity potential was estimated by measuring the turbidity of soil-suspension solutions after settling for 24 h. The mineralogy of the soils was dominated by four minerals-quartz, microcline, albite, and muscovite-with lesser amounts of hornblende, chlorite, kaolinite, illite, and mixed layer illite. The quartz content was the most variable of the soil mineralogy among the collected samples. Principal-components analysis (PCA) was used to examine relationships between turbidity potential and other soil properties. The variables considered in the PCA included turbidity potential, quartz content, albite content, mean size of soil particles, clay content, clay mineral content, zeta potential, conductivity, and pH of the soil-suspension solution. The first two components of the PCA explained 52% of the overall variation of the selected variables. The first component was possibly explained by physical properties such as the size of the soil particles; the second was correlated with chemical properties of the soils, for example dissolution and extent of weathering. Closer examination of the PCA results revealed that the quartz content of the soils was negatively correlated with their turbidity potential. A linear correlation (r = 0.63) was obtained between measured turbidity potential and that predicted using multiple regression analysis based on the content of clay-sized particles, clay minerals, and quartz, and the conductivity of the soil-suspension solution. PMID:18473181

Hur, Jin; Jung, Myung Chae

2009-06-01

75

Preliminary study on the radiological and physicochemical quality of the Umgeni Water catchments and drinking water sources in KwaZulu-Natal, South Africa.  

PubMed

Raw and potable water sample sources, from the Umgeni Water catchment areas (rivers, dams, boreholes) in central KwaZulu-Natal (South Africa), were screened for Uranium concentration and alpha and beta radioactivity. Test methods used were gas flow proportional counting for alpha-beta radioactivity, and kinetic phosphorescence analysis (KPA), for Uranium. The uranium levels (median = 0.525 ?g/L, range = <0.050-5.010) were well below the international World Health Organization (WHO) (2011) guideline for drinking-water quality (?15 ?g/L). The corresponding alpha and beta radioactivity was ?0.5 Bq/L (median = 0.084, Interquartile Range (IR) = 0.038, range = 0.018-0.094), and ?1.0 Bq/L (median = 0.114, IR = 0.096, range = 0.024-0.734), respectively, in compliance with the international WHO limits. For uranium radionuclide, the average dose level, at uranium level of ±0.525 ?g/L, was 0.06 ?Sv/a, which complies with the WHO reference dose level for drinking water (<0.1 mSv/a). There was a distinct trend of cluster of relatively higher Uranium levels of some sources that were found to be associated with the geology/geography and groundwater sources. Overall, the radiological water quality classification, with respect to WHO, is "Blue" - ideal; additional physicochemical analyses indicated good water quality. The analytical test methods employed were found to be suitable for preliminary screening for potential radioactive "hot spots". The observed Uranium levels, and the alpha/beta radioactivity, indicate contribution largely from Naturally Occurring Radioactive Material (NORM), with no significant health risk to humans, or to the environment. PMID:25151527

Manickum, T; John, W; Terry, S; Hodgson, K

2014-11-01

76

Constraining back-arc basin formation in the eastern Coral Sea: preliminary results from the ECOSAT voyage  

NASA Astrophysics Data System (ADS)

The eastern Coral Sea region is an underexplored area at the northeastern corner of the Australian plate, where long-lived interaction between the Pacific and Australian plate boundaries has resulted in an intricate assemblage of deep oceanic basins and ridges, continental fragments and volcanic products. A paucity of marine geophysical and geological data from this complex region has resulted in the lack of a clear conceptual framework to describe its formation, ultimately affecting our understanding of the connection between the plate boundaries of the SW Pacific and SE Asia. In particular, the tectonic relationship between two back-arc basins, the Santa Cruz and d'Entrecasteaux Basins, and the South Rennell Trough, has yet to be resolved. In October-November, 2012, we collected 6,200 km of marine magnetic, 6,800 km of gravity and over 13,600 km2 of swath bathymetry data from the eastern Coral Sea onboard the RV Southern Surveyor. A complementary dredging program yielded useful samples from 14 seafloor sites. Our preliminary geochemical interpretation of the dredge samples obtained from the South Rennell Trough reveal volcanic rocks resembling MORB or BABB-type basalts, similar in composition to the recently re-analysed and dated ORSTOM dredges from the area that yielded ~28 Ma MORB-like basalts. Swath bathymetry profiles from the Santa Cruz Basin reveal that the South Rennell Trough extends into this basin, with seafloor spreading fabric being parallel to the trough. Preliminary analysis of the three full and four partial new magnetic anomaly profiles across the Santa Cruz Basin, coupled with limited existing profiles, reveals that the basin may have formed between Chrons 13-18 (~32-38 Ma), with an extinct spreading ridge along the inferred continuation of the South Rennell Trough, consistent with ORSTOM age dates. Our results suggest that the South Rennell Trough is an extinct southwestward propagating spreading ridge, which may have initiated along a pre-existing zone of weakness. A preliminary interpretation of the 4 magnetic profiles collected in the d'Entrecasteaux Basin and existing profiles of seafloor fabric shows that this basin does not share a common seafloor spreading history with the Santa Cruz Basin, as has been suggested previously. Our preliminary interpretation of the relationship between the Santa Cruz Basin, South Rennell Trough and d'Entrecasteaux Basin requires a re-interpretation of existing models of the SW Pacific to take into account a southwestward propagating spreading ridge between 38-32 Ma, contemporaneous with seafloor spreading further south in the North Loyalty Basin. Further work on age-dating and geochemical analysis of the newly collected dredge samples and an in-depth analysis of the magnetic anomalies in the d'Entrecasteaux Basin may further yield important information concerning the tectonic evolution of the area.

Seton, M.; Williams, S.; Mortimer, N. N.; Meffre, S.; Moore, J.; Micklethwaite, S.; Zahirovic, S.

2013-12-01

77

Preliminary seismicity and focal mechanisms for the southern Great Basin of Nevada and California: January 1992 through September 1992  

SciTech Connect

The telemetered southern Great Basin seismic network (SGBSN) is operated for the Department of Energy`s Yucca Mountain Project (YMP). The US Geological Survey, Branch of Earthquake and Landslide Hazards, maintained this network until September 30, 1992, at which time all operational and analysis responsibilities were transferred to the University of Nevada at Reno Seismological Laboratory (UNRSL). This report contains preliminary earthquake and chemical explosion hypocenter listings and preliminary earthquake focal mechanism solutions for USGS/SGBSN data for the period January 1, 1992 through September 30, 1992, 15:00 UTC.

Harmsen, S.C.

1994-06-01

78

Tool for defining catchment similarity matrix  

NASA Astrophysics Data System (ADS)

It is important to classify catchments for many reasons, for example, for prediction in ungauged basins, model parameterization and watershed development. There have been many studies on catchment classification, but no silver bullet exists for choosing the most relevant measure of catchment similarity. The aim of this study is to explore a new measure of similarity among catchments, using a data depth function. We used a similarity measure called "Depth-Depth plot" (DD-plot) which measures similarity in the catchment flow dynamics in multiple dimension. The area under the convex hull of DD-plot can be used as similarity matrix to any clustering technique. In this study we used Affinity propagation (AP) clustering algorithm for grouping the similar catchments. Catchment classifications based on flow and physical characteristics were compared. We evaluate whether the similarity based on depth-depth plots provides a better basis for transferring parameter sets of a hydrological model between catchments. We used a case study of 21 catchments located in the Bay of Plenty region in the North Island of New Zealand. The catchments have a wide range of topographic properties, response behaviours and geological features. The TopNet hydrological model was calibrated for all the catchments and the transferability of model parameters among the similar catchments was tested by transferring the parameters from within the cluster group and outside the group. The results of parameter transferred with in group based on Nash-Sutcliffe coefficient are promising. Results also show that clustering based on our proposed depth-depth measure, catchment characteristics, flow, and flow indices are different. The catchment classification of this study can be used to improve regional flood forecasting capabilities.

Singh, Shailesh Kumar; McMillan, Hilary; Bárdossy, András; Fateh, Chebana

2014-05-01

79

Preliminary digital model of the Arikaree aquifer in the Sweetwater River basin, central Wyoming  

USGS Publications Warehouse

In central Wyoming, Potentially large supplies of ground water are available in the Sweetwater River basin from the Arikaree aquifer, which consists of the upper part of the White River, the Arikaree, and the Ogallala Formations. A preliminary digital model was developed for the Arikaree aquifer using a small amount of poorly distributed data, an estimated distribution of recharge, and a conceptual model of the Arikaree aquifer flow system. Calibration of the model was based on reproduction of the potentiometric surface and the base flow of the Sweetwater River in November 1975. Calculated steady-state hydraulic heads were within 50 feet of the observed heads in about 98 percent of the nodes. The calculated leakage from the Arikaree aquifer to he Sweetwater River in the western area was within about 12 percent of the leadage determined by gain and loss studies. In order to develop a comprehensive digital model that would respond to hydraulic stress in nearly the same manner as the actual aquifer flow system, measured responses of the aquifer to stress are needed. Also needed are additional data on aquifer characteristics, recharge to the aquifer, and stream-aquifer relationships. (Woodard-USGS)

Borchert, W. B.

1977-01-01

80

Preliminary report on coal pile, coal pile runoff basins, and ash basins at the Savannah River Site: effects on groundwater  

SciTech Connect

Coal storage piles, their associated coal pile runoff basins and ash basins could potentially have adverse environmental impacts, especially on groundwater. This report presents and summarizes SRS groundwater and soil data that have been compiled. Also, a result of research conducted on the subject topics, discussions from noted experts in the field are cited. Recommendations are made for additional monitor wells to be installed and site assessments to be conducted.

Palmer, E. [Westinghouse Savannah River Company, AIKEN, SC (United States)

1997-04-28

81

Impacts of climate change on the seasonality of low flows in 134 catchments in the River Rhine basin using an ensemble of bias-corrected regional climate simulations  

NASA Astrophysics Data System (ADS)

The impacts of climate change on the seasonality of low flows are analysed for 134 sub-catchments covering the River Rhine basin upstream of the Dutch-German border. Three seasonality indices for low flows are estimated, namely seasonality ratio (SR), weighted mean occurrence day (WMOD) and weighted persistence (WP). These indices are related to the discharge regime, timing and variability in timing of low flow events respectively. The three indices are estimated from: (1) observed low flows; (2) simulated low flows by the semi distributed HBV model using observed climate; (3) simulated low flows using simulated inputs from seven climate scenarios for the current climate (1964-2007); (4) simulated low flows using simulated inputs from seven climate scenarios for the future climate (2063-2098) including different emission scenarios. These four cases are compared to assess the effects of the hydrological model, forcing by different climate models and different emission scenarios on the three indices. The seven climate scenarios are based on different combinations of four General Circulation Models (GCMs), four Regional Climate Models (RCMs) and three greenhouse gas emission scenarios. Significant differences are found between cases 1 and 2. For instance, the HBV model is prone to overestimate SR and to underestimate WP and simulates very late WMODs compared to the estimated WMODs using observed discharges. Comparing the results of cases 2 and 3, the smallest difference is found in the SR index, whereas large differences are found in the WMOD and WP indices for the current climate. Finally, comparing the results of cases 3 and 4, we found that SR has decreased substantially by 2063-2098 in all seven subbasins of the River Rhine. The lower values of SR for the future climate indicate a shift from winter low flows (SR > 1) to summer low flows (SR < 1) in the two Alpine subbasins. The WMODs of low flows tend to be earlier than for the current climate in all subbasins except for the Middle Rhine and Lower Rhine subbasins. The WP values are slightly larger, showing that the predictability of low flow events increases as the variability in timing decreases for the future climate. From comparison of the uncertainty sources evaluated in this study, it is obvious that the RCM/GCM uncertainty has the largest influence on the variability in timing of low flows for future climate.

Demirel, M. C.; Booij, M. J.; Hoekstra, A. Y.

2013-05-01

82

Preliminary paleomagnetic results from Miocene Monterey Formation, Shell Beach, Pismo Basin, central California  

SciTech Connect

An excellently exposed 300-m thick section of the Monterey Formation at Shell Beach, Pismo basin, has been sampled at intervals of 2-5 m for paleomagnetic analysis. This study is part of an ongoing research aimed at providing detailed magnetostratigraphy and geochronology of the Monterey Formation sections from northern and central California. Here they report on the detailed magnetostratigraphy and diatom biostratigraphy of the upper 150 m of the Shell Beach section, which spans a 2-m.y. long interval in the upper middle Miocene (upper lower Mohnian). Their preliminary data reveal two distinct components of magnetization in about 75% of the dolomite samples and 40-60% of the samples from calcareous to siliceous shales and cherty porcelanitic rocks. The first of these components (a), which is removed at T less than or equal to 200/sup 0/C, is presumably recent viscous magnetization. The thermally discrete second component (b) had dual polarity and stable and consistent directions with a relatively narrow unblocking temperature range (200/sup 0/-400/sup 0/C). Usually this component remains blocked on heating to 450/sup 0/-500/sup 0/C and is then masked by unusually high intensity components of magnetochemical origin produced during heating in the lab. In their best samples, orthogonal vector diagrams show that b is the early characteristic remanence, and all evidence to date suggests that this component is pre-Pliocene-Pleistocene folding and most likely primary. By using diatom data extracted from their samples, they are attempting to obtain detailed magnetostratigraphy for this section of the Monterey Formation.

Khan, S.M.; Coe, R.S.; Barron, J.A.

1988-03-01

83

Implications for Fault and Basin Geometry in the Central California Coast Ranges from Preliminary Gravity and Magnetic Data  

NASA Astrophysics Data System (ADS)

Preliminary aeromagnetic and newly processed gravity data help define block-bounding faults and deep sedimentary basins in the central California Coast Ranges, ranging from the Hosgri fault east to the San Andreas fault and from Monterey Bay south to Pt. Conception. Interpretation of these data results in an improved framework for seismic hazard and groundwater studies. Aeromagnetic data include a new survey with a flight-line spacing of 800 m at a nominal 300 m above ground and covering 15,000 km2. More than 11,500 gravity measurements, reprocessed with terrain corrections calculated from 30-m DEMs, form a roughly 2-km grid over most of the study area. Combined potential-field data and existing geologic mapping, delineate major fault-bounded blocks in the central California Coast Ranges. Main block-bounding faults from west to east include the San Gregorio- Hosgri, San Luis-Willmar-Santa Maria River-Little Pine, Oceanic-West Huasna, Nacimiento, Rinconada-South Cuyama, San Juan-Chimineas-Morales, and San Andreas faults. Most of these faults have evidence of Quaternary activity. Gravity gradients indicate that the reach of the San Andreas fault bounding the Gabilan Range and the northern extension of the Rinconada fault bounding the Santa Lucia Range dip steeply southwestward and have a reverse component of slip. Magnetic and microseismicity data suggest that the northern reach of the Hosgri fault dips eastward. The potential-field data also delineate several deep sedimentary basins, such as the 3-4 km deep Cuyama basin, the Santa Maria basin, and several basins along and possibly offset by the Rinconada fault. Gravity data show that the main west-northwest-striking faults bounding the Cuyama basin dip away from the basin, indicating compression adjacent to the big bend in the San Andreas fault. Prominent gravity and magnetic highs northeast of the San Andreas fault immediately east of Cuyama Valley suggest that there the San Andreas fault dips southwest. Such dip information is important for estimating shaking potential of scenario earthquakes and for calculating geodetic deformation whereas basin shapes and fault locations are critical components for groundwater flow modeling.

Langenheim, V. E.; Jachens, R. C.; Graymer, R. W.; Wentworth, C. M.

2008-12-01

84

High frequency sampling of stable water isotopes for assessing runoff generation processes in a mesoscale urbanized catchment  

NASA Astrophysics Data System (ADS)

Experimental hydrology critically relies on tracer techniques to decipher and uncover runoff generation processes. Although tracer measurements contributed significantly to a better understanding of catchment functioning, their potential is not yet fully exploited. The temporal resolution of tracer measurements is typically relatively coarse, and applications are confined to a few locations. Additionally, experimental hydrology has focused primarily on pristine catchments, and the influence of anthropogenic effects remains largely unexplored. High frequency sampling of multiple tracers may therefore substantially enhance our understanding of hydrological processes and the impact of anthropogenic effects and enable a better protection and management of water resources and water quality. In this preliminary study we aim to assess runoff generation processes using geochemical and isotopic tracer techniques in the mesoscale Olewiger Bach catchment (24 km²) that is located in the low mountain ranges of the city of Trier, southwest Germany. The catchment is mainly characterized by quartzite and Devonian schist, overlain by fluvial sediments. Mixed land use prevails in the southern part of the basin, while the northern lower reaches are mainly urbanized. Several waste water treatment plants, separate sewer and stormwater management systems are present in parts of the catchment and contribute to the discharge of the main river. Tracer techniques employed in this ongoing study are twofold. A long term sampling of stable water isotopes (oxygen-18 and deuterium) was initiated in order to allow inferences about mean residence times of water in different catchment compartments, while event-based sampling using a multi-tracer approach was used to identify different runoff components and associated water pathways. Special attention is given to the observation of in-channel processes by assessing the dynamics of dissolved and particulate geochemical tracers and stable water isotopes during several controlled reservoir releases in the basin. The application of high resolution sampling of stable water isotopes employing a portable laser spectroscope is foreseen in this context.

Wrede, Sebastian; Fenicia, Fabrizio; Kurtenbach, Andreas; Keßler, Sabine; Bierl, Reinhard

2013-04-01

85

A new perspective on catchment storage gained from a nested catchment experiment in Luxembourg (Europe)  

NASA Astrophysics Data System (ADS)

Recent hydrological process research focussed on how much water a catchment can store and how these catchments store and release water. Storage can be a valuable metric for catchment description, inter-comparison, and classification. Further storage controls catchment mixing, non-linearities in rainfall-runoff transformation and eco-hydrological processes. Various methods exist to determine catchment storage (e.g. natural tracer, soil moisture and groundwater data, hydrological models). Today it remains unclear what parts of the catchment storage are measured with the different models. Here we present a new hydrometric approach to answer the question how much water a catchment can store. We tested our approach in a dense hydro-climatological monitoring network that encompasses 16 recording streamgauges and 21 pluviographs in the Alzette River basin in Luxembourg (Europe). Catchment scales are ranging from 0.47 to 285 km2 and they have clean- and mixed combinations of distinct geologies ranging from schists to marls, sandstone, dolomite and limestone. Previous investigations in the area of interest have shown that geology largely controls winter runoff coefficients. Here, we focus at how catchment geology is ultimately affecting catchment storage. We used the approach of Sayama et al. (2011) to compute catchment dynamic storage changes for each winter season over the period 2002-2012 (based on precipitation as input; discharge and evapotranspiration as output). We determined dynamic storage changes for each winter semester (October to March) in all 16 catchments over the period 2002-2012. At the beginning of each hydrological winter season, all catchments showed similar trends in storage change. A few weeks into the winter season, catchments with lowest permeability (e.g. marls) started to plateau. The highest storage values were reached several months later in the season in catchments dominated by permeable substrate (e.g. sandstone). For most catchments, we found strong correlations between baseflow prior to the recharge period (i.e. at initiation of the total storage calculations) and the seasonal maximum value of the total storage change calculations. In order to determine the maximum storage potential for each catchment, we fitted a trendline through the annual 'initial baseflow - maximum storage' populations. By extrapolating these trendlines to zero flow conditions, we obtained the maximum storage potential. Our results show that these maximum storage values clearly tend to be larger in catchments dominated by permeable substrate, compared to areas underlain by impermeable bedrock. In the latter, average filling ratios were found to be substantially higher (exceeding 80%) than in catchments dominated by permeable substrate (approximately 40%). These findings were confirmed by average seasonal winter runoff coefficients that are substantially higher in catchments dominated by impermeable bedrock (Pfister et al., in prep.). Our new approach allows a fast assessment of storage potential in catchments based on discharge, precipitation and evapotranspiration data. Pfister L. et al. 2014: Catchment storage, baseflow isotope signatures and basin geology: Is there a connection? In preparation. Sayama, T., McDonnell, J.J., Dhakal, A., Sullivan, K., 2011. How much water can a watershed store ? Hydrological Processes 25, 3899-3908.

Pfister, Laurent; Klaus, Julian; Hissler, Christophe; François Iffly, Jean; Gourdol, Laurent; Martinez-Carreras, Nuria; McDonnell, Jeffrey J.

2014-05-01

86

Preliminary paleomagnetic results from Miocene Monterey Formation, Shell Beach, Pismo Basin, central California  

Microsoft Academic Search

An excellently exposed 300-m thick section of the Monterey Formation at Shell Beach, Pismo basin, has been sampled at intervals of 2-5 m for paleomagnetic analysis. This study is part of an ongoing research aimed at providing detailed magnetostratigraphy and geochronology of the Monterey Formation sections from northern and central California. Here they report on the detailed magnetostratigraphy and diatom

S. M. Khan; R. S. Coe; J. A. Barron

1988-01-01

87

Preliminary gravity inversion model of basins east of Yucca Flat, Nevada Test Site, Nevada.  

SciTech Connect

The Yucca Flat eastern extension study area, a 14 kilometer by 45 kilometer region contiguous to Yucca Flat on the west and Frenchman Flat on the south, is being studied to expand the boundary of the Yucca Flat hydrogeologic model. The isostatic residual gravity anomaly was inverted to create a model of the depth of the geologic basins within the study area. Such basins typically are floored by dense pre-Tertiary basement rocks and filled with less-dense Tertiary volcanic and sedimentary rocks and Quaternary alluvium, a necessary condition for the use of gravity modeling to predict the depth to the pre-Tertiary basement rocks within the basins. Three models were created: a preferred model to represent the best estimate of depth to pre-Tertiary basement rocks in the study area, and two end-member models to demonstrate the possible range of solutions. The preferred model predicts shallow basins, generally less than 1,000m depth, throughout the study area, with only Emigrant Valley reaching a depth of 1,100m. Plutonium valley and West Fork Scarp Canyon have maximum depths of 800m and 1,000m, respectively. The end-member models indicate that the uncertainty in the preferred model is less than 200m for most of the study area.

Geoffrey A. Phelps; Carter W. Roberts, and Barry C. Moring

2006-03-17

88

Preliminary Risk Analysis of Nitrate Contamination in the Salinas Valley and Tulare Lake Basin of California, Including the Implementation of POU Devices in Small Communities  

E-print Network

i Preliminary Risk Analysis of Nitrate Contamination in the Salinas Valley and Tulare Lake Basin and Funding Options to Mitigate Nitrate Contamination By HOLLY ELYSE CANADA B.S. (Lehigh University) 2010 M for always taking the time to talk. I can't imagine surviving the nitrate project without Anna Fryjoff

Lund, Jay R.

89

Preliminary Assessment of the Social, Economic and Environmental Impacts of Water Hyacinth in the Lake Victoria Basin and the Status of Control  

Microsoft Academic Search

The paper presents preliminary data collected in an assessment of the social, economic and environmental impacts of water hyacinth in the Lake Victoria Basin. A summary of the status of control and strategies for the future is given. The report draws on field observations made, studies through interviews of affected communities and organisations, personal communications and published reports by scientists

A. M. Mailu

90

Potential impacts of climate change on tropospheric ozone in California: a preliminary episodic modeling assessment of the Los Angeles basin and the Sacramento valley  

SciTech Connect

In this preliminary and relatively short modeling effort, an initial assessment is made for the potential air quality implications of climate change in California. The focus is mainly on the effects of changes in temperature and related meteorological and emission factors on ozone formation. Photochemical modeling is performed for two areas in the state: the Los Angeles Basin and the Sacramento Valley.

Taha, Haider

2001-01-01

91

Magnetostratigraphy of Mesozoic shallow-water carbonates: Preliminary results from the Middle Jurassic of the Paris basin  

SciTech Connect

The use of sedimentary paleomagnetism has enhanced greatly our understanding of the timing of deposition and diagenesis of Cenozoic platform and reefal carbonates. Its application to similar but older deposits will have direct implications for economic exploration and development. The authors report here preliminary paleomagnetic results from the Middle Jurassic limestones of the Paris basin (France). The samples consist mainly of bioclastic and oolitic limestones deposited in ancient counterpart of the shallow-water environments of the Bahama platform. The Jurassic samples are stable to progressive, incremental demagnetization and exhibit magnetization patterns identical to Cenozoic rocks from the Bahama platform or Mururoa Atoll. The natural remanent magnetization of these limestones is weak and comprised between 7.7 x 10{sup {minus}9} to 1.8 x 10{sup {minus}8} AM{sup 2}/kg. Magnetic components of both normal and reversed polarity are observed. Paired isothermal remanent magnetization (IRM) and alternating field demagnetization experiments show that most of the remanence is lost between 20 and 45 mT, which is typical of single-domain biogenic magnetite or maghemite. The ratio of IRM at H{sub RG} to the saturation IRM ranges from 35 to 42% indicating a moderate to low interparticle interaction. This is confirmed by the anhysteretic remanent magnetization as compared with intact, freeze-dried cells of magnetotactic bacteria and chiton teeth. Magnetic minerals extracted from the Jurassic samples are examined to further confirm the occurrence of SD magnetite within the Middle Jurassic limestones of the Paris basin. The preliminary results suggest that the strata should be good for the paleomagnetic investigation of Mesozoic shallow-water carbonates.

Aissaoui, D.M.; Kirschvink, J.L. (California Inst. of Tech., Pasadena, CA (United States))

1991-03-01

92

Effect of initial conditions of a catchment on seasonal streamflow prediction using ensemble streamflow prediction (ESP) technique for the Rangitata and Waitaki River basins on the South Island of New Zealand  

NASA Astrophysics Data System (ADS)

Increased access to water is a key pillar of the New Zealand government plan for economic growths. Variable climatic conditions coupled with market drivers and increased demand on water resource result in critical decision made by water managers based on climate and streamflow forecast. Because many of these decisions have serious economic implications, accurate forecast of climate and streamflow are of paramount importance (eg irrigated agriculture and electricity generation). New Zealand currently does not have a centralized, comprehensive, and state-of-the-art system in place for providing operational seasonal to interannual streamflow forecasts to guide water resources management decisions. As a pilot effort, we implement and evaluate an experimental ensemble streamflow forecasting system for the Waitaki and Rangitata River basins on New Zealand's South Island using a hydrologic simulation model (TopNet) and the familiar ensemble streamflow prediction (ESP) paradigm for estimating forecast uncertainty. To provide a comprehensive database for evaluation of the forecasting system, first a set of retrospective model states simulated by the hydrologic model on the first day of each month were archived from 1972-2009. Then, using the hydrologic simulation model, each of these historical model states was paired with the retrospective temperature and precipitation time series from each historical water year to create a database of retrospective hindcasts. Using the resulting database, the relative importance of initial state variables (such as soil moisture and snowpack) as fundamental drivers of uncertainties in forecasts were evaluated for different seasons and lead times. The analysis indicate that the sensitivity of flow forecast to initial condition uncertainty is depend on the hydrological regime and season of forecast. However initial conditions do not have a large impact on seasonal flow uncertainties for snow dominated catchments. Further analysis indicates that this result is valid when the hindcast database is conditioned by ENSO classification. As a result hydrological forecasts based on ESP technique, where present initial conditions with histological forcing data are used may be plausible for New Zealand catchments.

Singh, Shailesh Kumar; Zammit, Christian; Hreinsson, Einar; Woods, Ross; Clark, Martyn; Hamlet, Alan

2013-04-01

93

Hydrologic comparison between a lowland catchment (Kielstau, Germany) and a mountainous catchment (XitaoXi, China) using KIDS model in PCRaster  

NASA Astrophysics Data System (ADS)

The KIDS model (Kielstau Discharge Simulation model) is a simple rainfall-runoff model developed originally for the Kielstau catchment. To extend its range of application we applied it to a completely different catchment, the XitaoXi catchment in China. Kielstau is a small (51 km2) lowland basin in Northern Germany, with large proportion of wetland area. And XitaoXi is a mesoscale (2271 km2) mountainous basin in the south of China. Both catchments differ greatly in size, topography, landuse, soil properties, and weather conditions. We compared two catchments in these features and stress on the analysis how the specific catchment characteristics could guide the adaptation of KIDS model and the parameter estimation for streamflow simulation. The Nash and Sutcliffe coefficient was 0.73 for Kielstau and 0.65 for XitaoXi. The results suggest that the application of KIDS model may require adjustments according to the specific physical background of the study basin.

Zhang, X.; Hörmann, G.; Fohrer, N.

2009-08-01

94

Preliminary study of solar ponds for salinity control in the Colorado River Basin. Technical report  

SciTech Connect

In this study, the Bureau of Reclamation investigates the technical and economic benefits of using solar salt-gradient ponds in the Colorado River Basin to provide salinity control and to produce project power and freshwater. It was assumed that the saline water needed for pond construction would be transported to one of two dry lakebeds in the Basin(Danby Dry Lake in southern California or Sevier Dry Lake in western Utah) as part of a salinity control/coal transport project. The ponds would be used to generate electric power that could be integrated with the Bureau's power grid or used in combination with thermal energy from the ponds to power commercially available desalination systems to produce freshwater. Economic benefits were compiled for two methods of concentrating the necessary brine for the ponds--one representing stage construction using collected brine only and the other using salt at the site to produce the concentrated brine.

Boegli, W.J.; Dahl, M.M.; Remmers, H.E.

1982-12-01

95

Preliminary gravity inversion model of basins east of Yucca Flat, Nevada Test Site, Nevada  

Microsoft Academic Search

The Yucca Flat eastern extension study area, a 14 kilometer by 45 kilometer region;\\u000acontiguous to Yucca Flat on the west and Frenchman Flat on the south, is being studied to expand;\\u000athe boundary of the Yucca Flat hydrogeologic model. The isostatic residual gravity anomaly was;\\u000ainverted to create a model of the depth of the geologic basins within the

Geoffrey A. Phelps; Carter W. Roberts; Barry C. Moring

2006-01-01

96

Preliminary gravity inversion model of Frenchman Flat Basin, Nevada Test Site, Nevada  

SciTech Connect

The depth of the basin beneath Frenchman Flat is estimated using a gravity inversion method. Gamma-gamma density logs from two wells in Frenchman Flat constrained the density profiles used to create the gravity inversion model. Three initial models were considered using data from one well, then a final model is proposed based on new information from the second well. The preferred model indicates that a northeast-trending oval-shaped basin underlies Frenchman Flat at least 2,100 m deep, with a maximum depth of 2,400 m at its northeast end. No major horst and graben structures are predicted. Sensitivity analysis of the model indicates that each parameter contributes the same magnitude change to the model, up to 30 meters change in depth for a 1% change in density, but some parameters affect a broader area of the basin. The horizontal resolution of the model was determined by examining the spacing between data stations, and was set to 500 square meters.

Phelps, G.A.; Graham, S.E.

2002-10-01

97

Managing the impact of gold panning activities within the context of integrated water resources management planning in the Lower Manyame Sub-Catchment, Zambezi Basin, Zimbabwe  

NASA Astrophysics Data System (ADS)

Riverbed alluvial gold panning activities are a cause for degradation of river channels and banks as well as water resources, particularly through accelerated erosion and siltation, in many areas of Zimbabwe. The lower Manyame sub-catchment located in the Northern part of the country is one such area. This study analysed the implications of cross-sectoral coordination of the management of panning and its impacts. This is within the context of conflicts of interests and responsibilities. A situational analysis of different stakeholders from sectors that included mining, environment, water, local government and water users who were located next to identified panning sites, as well as panners was carried out. Selected sites along the Dande River were observed to assess the environmental effects. The study determined that all stakeholder groups perceived siltation and river bank degradation as the most severe effect of panning on water resources, yet there were divergent views with regards to coordination of panning management. The Water Act of 1998 does not give enough power to management institutions including the Lower Manyame Sub-catchment Council to protect water resources from the impacts of panning, despite the fact that the activities affect the water resource base. The Mines and Minerals Act of 1996 remains the most powerful legislation, while mining sector activities adversely affect environmental resources. Furthermore, complexities were caused by differences in the definition of water resources management boundaries as compared to the overall environmental resources management boundaries according to the Environmental Management Act (EMA) of 2000, and by separate yet parallel water and environmental planning processes. Environmental sector institutions according to the EMA are well linked to local government functions and resource management is administrative, enhancing efficient coordination.

Zwane, Nonhlanhla; Love, David; Hoko, Zvikomborero; Shoko, Dennis

98

Nutrient removal using biosorption activated media: preliminary biogeochemical assessment of an innovative stormwater infiltration basin  

USGS Publications Warehouse

Soil beneath a stormwater infiltration basin receiving runoff from a 22.7 ha predominantly residential watershed in central Florida, USA, was amended using biosorption activated media (BAM) to study the effectiveness of this technology in reducing inputs of nitrogen and phosphorus to groundwater. The functionalized soil amendment BAM consists of a 1.0:1.9:4.1 mixture (by volume) of tire crumb (to increase sorption capacity), silt and clay (to increase soil moisture retention), and sand (to promote sufficient infiltration), which was applied to develop a prototype stormwater infiltration basin utilizing nutrient reduction and flood control sub-basins. Comparison of nitrate/chloride (NO3-/Cl-) ratios for the shallow groundwater indicate that prior to using BAM, NO3- concentrations were substantially influenced by nitrification or variations in NO3- input. In contrast, for the prototype basin utilizing BAM, NO3-/Cl- ratios indicate minor nitrification and NO3- losses with the exception of one summer sample that indicated a 45% loss. Biogeochemical indicators (denitrifier activity derived from real-time polymerase chain reaction and variations in major ions, nutrients, dissolved and soil gases, and stable isotopes) suggest NO3- losses are primarily attributable to denitrification, whereas dissimilatory nitrate reduction to ammonium is a minor process. Denitrification was likely occurring intermittently in anoxic microsites in the unsaturated zone, which was enhanced by increased soil moisture within the BAM layer and resultant reductions in surface/subsurface oxygen exchange that produced conditions conducive to increased denitrifier activity. Concentrations of total dissolved phosphorus and orthophosphate (PO43-) were reduced by more than 70% in unsaturated zone soil water, with the largest decreases in the BAM layer where sorption was the most likely mechanism for removal. Post-BAM PO43-/Cl- ratios for shallow groundwater indicate predominantly minor increases and decreases in PO43- with the exception of one summer sample that indicated a 50% loss. Differences in nutrient variations between the unsaturated zone and shallow groundwater may be the result of the intensity and duration of nutrient removal processes and mixing ratios with water that had not undergone significant chemical changes. Observed nitrogen and phosphorus losses demonstrate the potential, as well as future research needs to improve performance, of the prototype stormwater infiltration basin using BAM for providing passive, economical, stormwater nutrient-treatment technology to support green infrastructure.

O'Reilly, Andrew M.; Wanielista, Martin P.; Chang, Ni-Bin; Xuan, Zhemin; Harris, Willie G.

2012-01-01

99

Nutrient removal using biosorption activated media: preliminary biogeochemical assessment of an innovative stormwater infiltration basin.  

PubMed

Soil beneath a stormwater infiltration basin receiving runoff from a 23 ha predominantly residential watershed in north-central Florida, USA, was amended using biosorption activated media (BAM) to study the effectiveness of this technology in reducing inputs of nitrogen and phosphorus to groundwater. The functionalized soil amendment BAM consists of a 1.0:1.9:4.1 mixture (by volume) of tire crumb (to increase sorption capacity), silt and clay (to increase soil moisture retention), and sand (to promote sufficient infiltration), which was applied to develop an innovative stormwater infiltration basin utilizing nutrient reduction and flood control sub-basins. Comparison of nitrate/chloride (NO(3)(-)/Cl(-)) ratios for the shallow groundwater indicates that prior to using BAM, NO(3)(-) concentrations were substantially influenced by nitrification or variations in NO(3)(-) input. In contrast, for the new basin utilizing BAM, NO(3)(-)/Cl(-) ratios indicate minor nitrification and NO(3)(-) losses with the exception of one summer sample that indicated a 45% loss. Biogeochemical indicators (denitrifier activity derived from real-time polymerase chain reaction and variations in major ions, nutrients, dissolved and soil gases, and stable isotopes) suggest that NO(3)(-) losses are primarily attributable to denitrification, whereas dissimilatory nitrate reduction to ammonium is a minor process. Denitrification was likely occurring intermittently in anoxic microsites in the unsaturated zone, which was enhanced by the increased soil moisture within the BAM layer and resultant reductions in surface/subsurface oxygen exchange that produced conditions conducive to increased denitrifier activity. Concentrations of total dissolved phosphorus and orthophosphate (PO(4)(3-)) were reduced by more than 70% in unsaturated zone soil water, with the largest decreases in the BAM layer where sorption was the most likely mechanism for removal. Post-BAM PO(4)(3-)/Cl(-) ratios for shallow groundwater indicate predominantly minor increases and decreases in PO(4)(3-) with the exception of one summer sample that indicated a 50% loss. Differences in nutrient variations between the unsaturated zone and shallow groundwater may be the result of the intensity and duration of nutrient removal processes and mixing ratios with water that had undergone little biogeochemical transformation. Observed nitrogen and phosphorus losses demonstrate the potential, as well as the future research needs to improve performance, of the innovative stormwater infiltration basin using BAM for providing passive, economical, stormwater nutrient-treatment technology to support green infrastructure. PMID:22742948

O'Reilly, Andrew M; Wanielista, Martin P; Chang, Ni-Bin; Xuan, Zhemin; Harris, Willie G

2012-08-15

100

Preliminary Measurements Of N2O Partial Pressures In Rivers of Amazon Basin, Brazil  

Microsoft Academic Search

The concentrations of nitrous oxide (N2O), an important component of the greenhouse effect and with a long residence time in the atmosphere, have significantly increased in this century. The reasons for this atmospheric increase in N2O are still partially unexplained. This uncertainty is worse in relation to aquatic environments. Here we report on preliminary measurements of N2O partial pressures in

C. B. Oliveira; M. F. Rasera; A. V. Krusche; R. L. Victoria; J. E. Richey; H. B. Cunha; B. M. Gomes

2006-01-01

101

Gauging the Ungauged Catchment: the Value of Stream Level Observations  

NASA Astrophysics Data System (ADS)

Streamflow estimation in ungauged basins is especially challenging in data-scarce regions and it might be reasonable to take at least a few measurements. Recent studies demonstrated that few streamflow measurements, representing data that could be measured with limited efforts in an ungauged basin, might be needed to constrain runoff models for simulations in ungauged basins. While in these previous studies we assumed that few streamflow measurements were taken during different points in time over one year, obviously it would be reasonable to (also) measure stream levels. Several approaches could be used in practice for such stream level observations: water level loggers have become less expensive and easier to install and can be used to obtain continuous stream level time series; stream levels will in the near future be increasingly available from satellite remote sensing resulting in evenly space time series; community-based approaches (e.g., crowdhydrology.org), finally, can offer level observations at irregular time intervals. Here we present a study where a catchment runoff model (the HBV model) was calibrated for gauged basins in Switzerland assuming that only a subset of the data was available. We pretended that only stream level observations at different time intervals, representing the temporal resolution of the different observation approaches mentioned before, and a small number of streamflow observations were available. The model, which was calibrated based on these data subsets, was then evaluated on the full observed streamflow record. Preliminary results indicate that the combination of (very) few streamflow observations with stream level observations can provide surprisingly good model simulation results. These results are encouraging for hydrological observations in data scarce regions as level observations are much easier to obtain than streamflow observations. Based on runoff modeling it might be possible to derive streamflow series from level observations using loggers, satellites or community-based approaches. The approach presented here also allows comparing the value of different kind of (level) observations and, thus, to guide the monitoring of previously ungauged basins.

Seibert, J.; Vis, M.; Pool, S.

2013-12-01

102

Preliminary examination of microearthquake activity along the Eastern Lau Spreading Center and southern Lau Basin  

NASA Astrophysics Data System (ADS)

Presently, a hydroacoustic array is moored in the Lau Basin (Bohnenstiehl et al.) to examine wave propagation in the water column and tectonics associated with the basin as a whole. One region that has suffered from a lack of seismic observations is the Eastern Lau Spreading Center (ELSC) a RIDGE 2000 Integrated Studies Site. The ELSC, west of the Tongan islands located along the forearc of the Tongan subduction system, is opening the southern portion of the Lau Basin in a wedge-like fashion. Spreading rates vary along the length of the ELSC from 97 mm/yr at the northern end to ~40 mm/yr towards the southern end, with the southern end closer to and more strongly affected by the arc as seen in ridge morphology and basalt chemistry. Active arc volcanoes are within 100 km of the spreading center and several hydrothermal sites are found along the axis. The Tongan subduction system is also one of the most seismically active tectonic systems on the Earth. However, while GSN stations record considerable activity along the Tongan forearc and along plate boundaries further to the north in the basin, almost no earthquake activity has been recorded along the ELSC. The few events unambiguously associated with the ELSC all lie at the northern terminus where the ridge system steps leftward with an overlapping spreading center. The LABATTS experiment, a 3 month OBS deployment in 1994 along the central portion of the basin, recorded hundreds of shallow events throughout the backarc region. The experiment recorded dozens of events associated with swarms near the northern terminus but still less than a handful along the length of the ELSC itself. Some of this lack may be due to the highly attenuative mantle beneath the Lau Basin and less than optimal experiment geometry for LABATTS (which was focussed on tomographic structure). However, numerous other events with similar difficulties are observed to the north and east, suggesting that active seismicity along the ridge primarily comprises events smaller than magnitude 2 - 3, below the likely detection threshold of LABATTS, and offering no information regarding timing or distribution of cracking or broader tectonic deformation. While data recovery has not yet occurred for the hydroacoustic array, the L-SCAN active source seismic experiment carried out in Jan - March of this year has provided some fortuitous results on microseismicity of the ELSC. The L-SCAN experiment deployed 84 seismometers on the seafloor for recording airgun shots along and under the axis. Throughout the data, there is clearly noticeable microseismic earthquake activity during the airgunning. Initial data processing suggests a high rate of local seismicity in the area. With rates in some places approaching 15 events per hour. These high rates of activity allow us to get a glimpse of patterns of ELSC microseismic activity in both time and space. In addition, within weeks after disembarkment, Tonga experienced both an underwater eruption within 50 km of the array footprint and a magnitude 7.6 subduction thrust event ~200 km south of the array footprint. Further analysis of the data could shed further light on any precursor activity associated with the nearby eruption and large trench earthquake.

Conder, J. A.; Dunn, R.; Godfrey, K. E.

2009-12-01

103

Rhaetian extensional tectonics in the Slovenian Basin (Southern Alps): Preliminary results of an outcrop study  

NASA Astrophysics Data System (ADS)

A Late Triassic palaeogeographic position of the Slovenian Basin on the passive continental margin of the Neotethys Ocean to the East and later the Alpine Tethys to the West, implements that its evolution intimately depended on the events in these two areas of extension. Recent research of the "Ba?a dolomite", the typical Norian-Rhaetian lithologic unit of the Slovenian Basin, resulted in recognition of four extensional tectonic events (Gale et al., this volume). The Lower and Middle Norian tectonic pulses can be recognized throughout the basin. A weakened tectonic activity was recognized in the Rhaetian, followed by more pronounced, but spatially restricted tectonics at the Triassic-Jurassic boundary. Extensional tectonics was attributed to the diminishing rifting in the Neotethys area and to the incipient opening of the Alpine Tethys (Gale et al., this volume). The ongoing fieldwork in the vicinity of Škofja Loka (central Slovenia) resulted in the discovery of palaeofaults in the small-sized quarry that directly evidences the Late Triassic extensional tectonics. Based on superposition, the observed section of the "Ba?a dolomite" is of the Rhaetian age. The discovery is particularly important because it represents the first direct documentation of the Late Triassic down-faulting in the region. The lowest strata exposed consist of highly bituminous bedded dolostones with scour structures and several meters of mud-supported dolo-breccias. Breccias were downthrown along a normal fault and the created accommodation space filled with bedded dolostone. After complete leveling of topography, another differentiation took place, during which a new normal fault originated, whereas the pre-existing fault was reactivated in an antithetic sense. Thin-bedded dolostones were deposited during slowly abiding movements. The final cessation of tectonics is marked by a uniform deposition of massive dolostone, entirely overlying the fault-dissected sediments.

Opr?kal, P.; Gale, L.; Kolar-Jurkovšek, T.; Roži?, B.

2012-04-01

104

Geology of the Ahuas area in the Mosquitia basin of Honduras: Preliminary report  

SciTech Connect

Following a 36-fold seismic survey that covered 460 km, two exploratory wells were drilled between July 1991 and August 1993 in the Ahuas area, on the Patuca tectonic belt, in the Mosquitia savannah in northeastern Honduras. The Embarcadero 1 well encountered only dense, barren, gray and red siliciclastics and some phyllite at total depth. The RaitiTara 1 well also drilled mostly barren, but less dense, red beds that included some Upper Cretaceous limestone conglomerate in the lower section. We did not find source or reservoir rocks in either well, nor did we find hydrocarbon shows. The absence of Lower Cretaceous limestone in both wells is significant because more than 1500 m of limestone are exposed 35-50 km southwest in the Colon Mountains. The lithology of the clastics in the Embarcadero well is similar to Middle and Upper Jurassic formations in central Honduras. The lithology of the softer red beds in the Raiti-Tara well suggests they are Tertiary fill in a pull-apart basin. The Mosquitia basin, including the Ahuas area, probably was on the seaward side of the Chortis block (once part of Mexico) and received only Jurassic sediments until it was elevated by arc magmatism in the Early Cretaceous. However, thick Lower Cretaceous platform carbonates were deposited some distance inland. Lateral forces in the early Late Cretaceous caused the outer edge of Chortis to break up, carrying the Colon carbonate block up to 50 km northwest by sinistral fault movement. Later, antithetic dextral displacement offset the various blocks and created pull-apart basins that filled with Tertiary sediments. In the early Paleocene, compression from a spreading center to the southeast ruptured the Jurassic rocks, creating a decollement and later thrusting. No complete petroleum system seems to exist along the axis of the uplifted Patuca tectonic belt largely because of the lack of organic-rich source rocks and the presence of complicated young structures.

Mills, R.A.; Barton, R. [True Oil Co., Casper, WY (United States)

1996-10-01

105

Magnetic Fabric of the Itararé Group, Paraná Basin Brazil: Preliminary Results  

NASA Astrophysics Data System (ADS)

The late Paleozoic Itararé Group and equivalent beds in the Paraná Basin of Brazil extend into Paraguay, Argentina, and Uruguay. The Itararé Group contains the most extensive lithological record of Gondwana glaciation in the world. The succession has a maximum subsurface thickness of around 1400 m and extends over a total area greater than 1 million km2. The lower boundary of the Itararé Group is nonconformable with Precambrian to early Paleozoic crystalline basement and with Devonian strata of the Furnas and Ponta Grossa Formations, which together constitute the base of the Gondwana supersequence of the Paraná Basin. This boundary encompasses a hiatus that is loosely estimated in 45 Ma. The upper contact with the overlying Rio Bonito Formation is described as conformable to partially erosional. We performed our study on 13 sites from sedimentary rocks (sandstones and siltites) from the Itararé beds in the Brazilian portion of the Paraná Basin (mainly in São Paulo State). Magnetic fabrics were determined on oriented cylindrical specimens (2.54 cm x 2.2 cm) using the anisotropy of low-field magnetic susceptibility (AMS). Rock-magnetic analyses reveal that magnetite is the main magnetic mineral. In one of the sampled site, however, the ferromagnetic minerals are both magnetite and hematite. Regarding the eingenvector orientations, the sites usually gave good results. The analysis at the individual-site scale defines three AMS fabric types. The first type (7 sites) shows Kmin perpendicular to the bedding plane while Kmax and Kint are scattered within the bedding plane itself. This fabric is usually interpreted as primary (sedimentary-compactional), typical of undeformed sediments. The second type (5 sites) shows good clustering of the AMS principal axes with Kmin still sub-perpendicular to the bedding plane. The third type, pertaining to an intensely folded site previously interpreted as slumped, is characterized in geographic coordinates by well-clustered Kmax in the bedding plane, while Kmin and Kint are distributed along a NE-SW girdle with a sub-vertical, yet elongate Kmin distribution. In stratigraphic coordinates Kmax maintains the same NNW-SSE clustering, yet Kmin and Kint become scattered within the girdle. The second fabric type would be interpreted as combination of sedimentary-compactional and tectonic contributions if some strain markers or evidence for tectonic deformation had been found in the studied area. On the other hand, the tight Kmax grouping in this fabric type could be explained by the action of currents since they cause Kmax to be aligned sub-parallel to the paleocurrent direction.

Raposo, M. B.; Bilardello, D.; Santos, P. R.

2012-12-01

106

Water Governance Reform and Catchment Management in the Mekong Region  

Microsoft Academic Search

This article investigates complexities and dynamics of water governance reforms at a number of levels in the Mekong Region. It looks comparatively at countries within the region and at the Mekong as a transboundary basin. The study takes catchment management processes as a focus for reform agendas related to water and relates water management in a river basin context to

Philip Hirsch

2006-01-01

107

CHARIS - The Contribution to High Asian Runoff from Ice and Snow, Preliminary results from the Upper Indus Basin, Pakistan  

NASA Astrophysics Data System (ADS)

The goal of the CHARIS project is to improve the understanding of the regional water resources of High Asia. In order to achieve this goal CHARIS is a cross-boundary exercise with University of Colorado scientists working directly with researchers at institutions in nine different nations where these ice and snow resources are located (Bhutan, Nepal, India, Pakistan, Afghanistan, Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan). These countries contain the headwaters of the Brahmaputra, Ganges, Indus, Syr Darya and Amu Darya rivers. This collaboration includes both joint research and capacity building that includes augmented field programs and technical training. While it is generally accepted that a significant component of these water resources results from the melting of glacier ice and seasonal snow, the actual water volume available from these two individual sources remains uncertain. The amount, timing, and spatial patterns of snow and ice melt play key roles in providing water for downstream irrigation, hydropower generation, and general consumption. The fundamental objective of this collaborative study is to develop a thorough and systematic assessment of the separate contributions from seasonal snow melt and from glacier ice melt to the water resources originating across the region. To accomplish project objectives, a suite of satellite remote sensing, reanalysis and ground based data are applied as input to specific snow and ice melt models. Gridded maps of snow and glacier area/elevation are used as input to temperature-index melt models to estimate runoff from snow covered grid cells, based on cell area and melt depth. Glacier melt is estimated in the same way, once seasonal snow has disappeared from glacierized grid cells. The melt models are driven by daily mean temperature from reanalysis data. We are comparing the melt volume time series generated from temperature-index models with measured river discharge volumes and comparing the regional scale results with local sub-basin studies based on energy balance modeling approaches. We are also evaluating the accuracy of the melt model results using isotopic and geochemical tracers to identify and quantify the sources of water (ice melt, snow melt, rainfall and ground water) flowing into selected rivers representing the major hydro-climates of the study area. Preliminary results are presented for the Upper Indus Basin, and the Hunza sub-basin, for the period 2000-2012.

Armstrong, R. L.; Barrett, A. P.; Brodzik, M.; Fetterer, F. M.; Hashmey, D.; Horodyskyj, U. N.; Khalsa, S.; Racoviteanu, A.; Raup, B. H.; Williams, M. W.; Wilson, A.

2013-12-01

108

Catchment–coastal zone interaction based upon scenario and model analysis: Elbe and the German Bight case study  

Microsoft Academic Search

This paper presents a holistic strategy on the interaction of activities in the Elbe river basin and their effects on eutrophication in the coastal waters of the German Bight. This catchment–coastal zone interaction is the main target of the EUROCAT (EUROpean CATchments, catchment changes and their impact on the coast) research project, with the Elbe being one of eight case

J. Hofmann; H. Behrendt; A. Gilbert; R. Janssen; A. Kannen; J. Kappenberg; H. Lenhart; W. Lise; C. Nunneri; W. Windhorst

2005-01-01

109

Reservoir property estimation in Pohang Basin, South Korea for the preliminary CO2 storage prospect  

NASA Astrophysics Data System (ADS)

Geological CO2 storage draws a great attention globally and South Korea also look for proper storage sites to reduce CO2 emission. The Pohang Basin area, located at the southeastern part of Korea, is regarded as a good candidate for CO2 storage, since the basin is believed to have good sand intervals, and there are various CO2 sources, such as a steel mill and a car factory around the area. However, there are not many geophysical data (core, logs, seismic, etc.) available since the area is highly industrialized and the target site is located offshore. There are a few well logs sparsely located, and core data are not many either since the target formation is semi- to unconsolidated clastics. To overcome these difficulties, we firstly go back to regional geology and determine the regional 3D distribution of target formation. Then, we obtain onshore outcrop samples from the same target formation to compliment scarce core data. The core and outcrop samples are not well-consolidated, which makes lab measurements highly difficult. We adopt a computational rock physics method, which estimates porosity and permeability on 3D microstructures statistically reconstructed from thin section images. The average values of porosity and permeability of outcrop samples are 25% and 1,000mD, and those from one core data 17% and 100mD, respectively. Other cores from the same formation do not give any significant permeability values. Thus, we categorize the formation into two subgroups, good and bad. Next, we visit well-log data and categorize intervals into two subgroups, and apply the our computation results to the good group. Finally, we can give maps of reservoir properties for the target formation. Although we can give only approximate values/relations of reservoir properties for good interval, it helps evaluate overall prospect of the target formation. Acknowledgements: This research was supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Trade, Industry and Energy of Korea (GP2012-030).

Han, J.; Keehm, Y.

2013-12-01

110

Preliminary results of polarization signatures for glacial moraines in the Mono Basin, Eastern Sierra Nevada  

NASA Technical Reports Server (NTRS)

The valleys of the Mono Basin contain several sets of lateral and terminal moraines representing multiple stages of glaciation. The semi-arid climate with slow weathering rates preserved sequences of nested younger moraines within older ones. There is a well established relative chronology and recently exposure dating provided a new set of numerical dates. The moraines span the late Wisconsin (11-25 ka) to the Illinoian (130-190 ka) glaciations. The Mono Basin area was used as a 'calibration site' to establish remote dating techniques for eventual transfer to the more inaccessible but geomorphically and climatically similar moraines of the South American Andes Mountains. Planned polarimetric synthetic aperture radar (SAR) imagery acquired by JPL AIRSAR (South American Campaign) and SIR-C (Andes super-site) are analyzed to establish chronologies of previously undated moraine sequences in a study of Pleistocene climatic change in the Southern Hemisphere. The dry climate and sparse vegetation is also favorable for correlation of ground surface roughness with radar polarization signature. The slow weathering processes acting over thousands of years reduce the size, frequency, and angularity of surface boulders while increasing soil development on the moraines. Field observations based on this hypothesis result in relative ages consistent with those inferred from nested position within the valley. Younger moraines, therefore, will appear rougher than the older smoother moraines at scales measurable at AIRSAR wavelengths. Previously documented effects of ground surface roughness on polarization signatures suggest that analysis of moraine polarization signatures can be useful for relative dating. The technique may be extended to predict numerical ages. The data set reported were acquired on 8 Sep. 1989 with the JPL Airborne SAR (AIRSAR) collecting polarimetric imagery at C- (5.6 cm), L- (24 cm), and P-band (68 cm) with a flight-line parallel to the strike of the mountains. Phase calibration was performed on the analyzed scene by setting the co-phase of a smooth lake to zero as described. Absolute amplitude calibration was not possible because corner reflectors were not deployed.

Forster, Richard R.; Fox, Andrew N.; Isacks, Bryan

1992-01-01

111

Channel erosion and sediment transport in Pheasant Branch basin near Middleton, Wisconsin; a preliminary report  

USGS Publications Warehouse

The purpose of this 5-year study is to (1) evaluate the sediment transport, streamflow characteristics, and stream-channel morphology, (2) relate the above to land-use practices; and (3) evaluate the effect that changes in land-use practices will have on Pheasant Branch basin near Middleton, Wis. This report presents findings of sediment transport, streamflow characteristics, and stream-channel morphology from the first year of the study and documents historical erosion. The study is being conducted by the U.S. Geological Survey in cooperation with the city of Middleton and the Wisconsin Geological and Natural History Survey. Pheasant Branch, a tributary to Lake Mendota, drains 23.1 square miles of glacial drift. Channel erosion is severe within Middleton, requiring extensive use of erosion-control structures. Occasionally, channel dredging near the mouth and into Lake Mendota is required for boating. Comparison of stream-channel surveys of 1971 and 1977 shows the lowest part of the channel lowered 3 to 4 feet at some sites in the urban reach from U.S. Highway 12 downstream to Century Avenue. Downstream from Century Avenue, channel width increased from about 35 to 48 feet and channel cross-section area increased about 86 percent. A survey of Pheasant Branch in 1971 provided data for quantification of stream-channel changes since that time. Six erosion-control structures previously installed appear to have had some benefit in controlling head cutting in the channel. (USGS).

Grant, R. Stephen; Goddard, Gerald

1980-01-01

112

First ediacaran fauna occurrence in northeastern Brazil (jaibaras basin, ?ediacaran-cambrian): preliminary results and regional correlation.  

PubMed

This study reports the first known occurrence of the Ediacaran fauna in northeastern Brazil (at Pacujá Municipality, northwestern state of Ceará) and presents preliminary interpretations of its significance. Regional correlation indicates that the fossils originated in the Jaibaras Basin and that they may represent a new geological system. The depositional environment can be attributed to a fluviomarine system. Nine Ediacaran species can be identified, including members of pandemic groups (e.g., Charniodiscus arboreus Glaessner, 1959; ?Charniodiscus concentricus Ford, 1958; Cyclomedusa davidi Sprigg, 1947; Ediacaria flindersi Sprigg, 1947; and Medusinites asteroides Sprigg, 1949) and endemic groups (e.g., Kimberella quadrata Glaessner & Wade, 1966; Palaeophragmodictya reticulata Gehling & Rigby, 1996; Parvancorina minchami Glaessner, 1958; and Pectinifrons abyssalis Bamforth, Narbonne, Anderson, 2008). Three ichnogenera are also present: Arenicolites Salter, 1857; Palaeophycus Hall, 1987; and Planolites Nicholson, 1873. The relative age of the deposits is between ?Ediacaran and Cambrian, and the fauna resembles the White Sea Assemblage. The bioturbation presents typical unbranched Ediacaran ichnogenera with little depth in the substrate. This previously unknown occurrence of the Ediacaran fauna reinforces the importance of the state of Ceará to Brazilian and global palaeontology. PMID:25140502

Barroso, Francisco R G; Viana, Maria Somália S; de Lima Filho, Mario F; Agostinho, Sonia M O

2014-09-01

113

Preliminary report on coal resources of the Wyodak-Anderson coal zone, Powder River Basin, Wyoming and Montana  

USGS Publications Warehouse

The National Coal Resource Assessment (NCRA) project by the U.S. Geological Survey is designed to assess US coal with the greatest potential for development in the next 20 to 30 years. Coal in the Wyodak-Anderson (WA) coal zone in the Powder River Basin of Wyoming and Montana is plentiful, clean, and compliant with EPA emissions standards. This coal is considered to be very desirable for development for use in electric power generation. The purpose of this NCRA study was to compile all available data relating to the Wyodak- Anderson coal, correlate the beds that make up the WA coal zone, create digital files pertaining to the study area and the WA coal, and produce a variety of reports on various aspects of the assessed coal unit. This report contains preliminary calculations of coal resources for the WA coal zone and is one of many products of the NCRA study. Coal resource calculations in this report were produced using both public and confidential data from many sources. The data was manipulated using a variety of commercially available software programs and several custom programs. A general description of the steps involved in producing the resource calculations is described in this report.

Ellis, Margaret S.; Gunther, Gregory L.; Flores, Romeo M.; Ochs, Allen M.; Stricker, Gary D.; Roberts, Steven B.; Taber, Thomas T.; Bader, Lisa R.; Schuenemeyer, John H.

1998-01-01

114

Monitoring of wild fish health at selected sites in the Great Lakes Basin: methods and preliminary results  

USGS Publications Warehouse

During fall 2010 and spring 2011, a total of 119 brown bullhead (Ameiurus nebulosus), 136 white sucker (Catostomus commersoni), 73 smallmouth bass (Micropterus dolomieu), and 59 largemouth bass (M. salmoides) were collected from seven Great Lakes Basin Areas of Concern and one Reference Site. Comprehensive fish health assessments were conducted in order to document potential adverse affects from exposure to complex chemical mixtures. Fish were necropsied on site, blood samples obtained, pieces of liver, spleen, kidney, gill and any abnormalities placed in fixative for histopathology. Liver samples were saved for gene expression analysis and otoliths were removed for aging. A suite of fish health indicators was developed and implemented for site comparisons and to document seasonal effects and species differences in response to environmental conditions. Organism level (grossly visible lesions, condition factor), tissue level (microscopic pathology, organosomatic indices, micronuclei, and other nuclear abnormalities), plasma factors (reproductive steroid hormones, vitellogenin), and molecular (gene expression) indicators were included. This report describes the methods and preliminary results.

Blazer, Vicki S.; Mazik, Patricia M.; Iwanowicz, Luke R.; Braham, Ryan; Hahn, Cassidy; Walsh, Heather L.; Sperry, Adam

2014-01-01

115

Modeling fluid flow and heat transfer at Basin and Range faults: preliminary results for Leach hot springs, Nevada  

USGS Publications Warehouse

The hydrothermal systems of the Basin and Range Province are often located at or near major range bounding normal faults. The flow of fluid and energy at these faults is affected by the advective transfer of heat and fluid from an to the adjacent mountain ranges and valleys, This paper addresses the effect of the exchange of fluid and energy between the country rock, the valley fill sediments, and the fault zone, on the fluid and heat flow regimes at the fault plane. For comparative purposes, the conditions simulated are patterned on Leach Hot Springs in southern Grass Valley, Nevada. Our simulations indicated that convection can exist at the fault plane even when the fault is exchanging significant heat and fluid with the surrounding country rock and valley fill sediments. The temperature at the base of the fault decreased with increasing permeability of the country rock. Higher groundwater discharge from the fault and lower temperatures at the base of the fault are favored by high country rock permabilities and fault transmissivities. Preliminary results suggest that basal temperatures and flow rates for Leach Hot Springs can not be simulated with a fault 3 km deep and an average regional heat flow of 150 mW/m2 because the basal temperature and mass discharge rates are too low. A fault permeable to greater depths or a higher regional heat flow may be indicated for these springs.

López, Dina L.; Smith, Leslie; Storey, Michael L.

1994-01-01

116

Preliminary Paleomagnetic Results From Tertiary Rocks of Sedimentary Basins in Northern Vietnam and Tectonic Implications  

NASA Astrophysics Data System (ADS)

The South China Sea (SCS) is a classical representative of western Pacific marginal seas and contains records of Cenozoic tectonic events of SE Asia. The SCS has been at the center stage of many first-order tectonic and paleoclimatic events since the Mesozoic. One clear way to evaluate the relationship between tectonic uplift and climate is to study the resulting changes in marginal sea strata. To this end, we will conduct an integrated paleomagnetic and stratigraphic investigation on Tertiary strata from Phu Tho and Yen Bai provinces, northern Vietnam to help understand the causal linkages among geological and tectonic events and their consequences related to the SCS evolution. We will collect paleomagnetic samples at sections where the most continuous, complete, and best preserved Eocene-Miocene successions. Standard paleomagnetic field tests, such as the fold, reversal, and conglomerate tests will be used to determine the relative age of the magnetization. In addition to detailed thermal and alternating field demagnetization and analysis, selected samples will also be subjected to several rock magnetic analyses to identify magnetic carriers in the rocks. In particular, the hysteresis parameters Jrs/Js and Hcr /Hc ratios will enable us to apply techniques for detecting low-temperature remagnetization of sedimentary rocks. Preliminary finding of this ongoing project will be presented.

Zhao, X.; Liu, Z.; Le, K.; Zhao, Y.; Hoang, V.; Phan, D.

2013-12-01

117

Calculating specific catchment area  

NASA Astrophysics Data System (ADS)

Specific catchment area, defined as the area of land upslope of a width of contour, divided by the contour width, is a commonly used quantity in hydrology to describe complex terrain for analyzing water flow on hill slopes; it can be a surrogate for water discharge per unit flow width. Although specific catchment area is important in hydrological, ecological, and geological studies, it can be difficult to estimate. Gallant and Hutchinson provide a simple differential equation that describes the rate of change of specific catchment area along a flow path. The equation can be directly integrated to calculate specific catchment area at any point on a digital elevation model. The method avoids use of catchment area and width estimates, which have errors. Although the method is more computationally intense than most methods for calculating specific catchment area, it can be used as a reference against which other methods can be tested. (Water Resources Research, doi:10.1029/ 2009WR008540, 2011)

Tretkoff, Ernie

2011-07-01

118

Calculating specific catchment area  

NASA Astrophysics Data System (ADS)

Specific catchment area, defined as the area of land upslope of a width of contour, divided by the contour width, is a commonly used quantity in hydrology to describe complex terrain for analyzing water flow on hill slopes; it can be a surrogate for water discharge per unit flow width. Although specific catchment area is important in hydrological, ecological, and geological studies, it can be difficult to estimate. Gallant and Hutchinson provide a simple differential equation that describes the rate of change of specific catchment area along a flow path. The equation can be directly integrated to calculate specific catchment area at any point on a digital elevation model. The method avoids use of catchment area and width estimates, which have errors. Although the method is more computationally intense than most methods for calculating specific catchment area, it can be used as a reference against which other methods can be tested. (Water Resources Research, doi:10.1029/2009WR008540, 2011)

Tretkoff, Ernie

2011-07-01

119

Diatoms as a fingerprint of sub-catchment contributions to meso-scale catchment runoff  

NASA Astrophysics Data System (ADS)

In recent years, calls were made for new eco-hydrological approaches to improve understanding of hydrological processes. Recently diatoms, one of the most common and diverse algal groups that can be easily transported by flowing water due to their small size (~10-200 µm), were used to detect the onset and cessation of surface runoff to small headwater streams and constrain isotopic and hydro-chemical hydrograph separation methods. While the method showed its potential in the hillslope-riparian zone-stream continuum of headwater catchments, the behavior of diatoms and their use for hydrological process research in meso-scale catchments remains uncertain. Diatoms can be a valuable support for isotope and hydro-chemical tracer methods when these become ambiguous with increasing scale. Distribution and abundance of diatom species is controlled by various environmental factors (pH, soil type, moisture conditions, exposition to sunlight, etc.). We therefore hypothesize that species abundance and composition can be used as a proxy for source areas. This presentation evaluates the potential for diatoms to trace source-areas in the nested meso-scale Attert River basin (250 km2, Luxembourg, Europe). We sampled diatom populations in streamwater during one flood event in Fall 2011 in 6 sub-catchments and the basin outlet - 17 to 28 samples/catchment for the different sampling locations. Diatoms were classified and counted in every individual sample. In total more than 400 diatom species were detected. Ordination analysis revealed a clear distinction between communities sampled in different sub-catchments. The species composition at the catchment outlet reflects a mixing of the diatom composition originating from different sub-catchments. This data suggests that diatoms indeed can reflect the geographic origin of stream water at the catchment outlet. The centroids of the ordination analysis might be linked to the physiographic characteristics (geology and land use) of the catchments. In a next step we will increase sample size of catchments to further evaluate if these distinct species assemblages are characteristic for different physiographic units and can indeed unambiguously trace catchment source areas. We will compare the results with classical source area hydrograph separations.

Klaus, Julian; Wetzel, Carlos E.; Martinez-Carreras, Nuria; Ector, Luc; Pfister, Laurent

2014-05-01

120

Preliminary basin analysis of late Proterozoic-Cambrian post-rift strata, southeast Idaho thrust belt  

SciTech Connect

Strata of the Brigham Group in the Paris-Putnam plate of the southeastern Idaho thrust belt span the late Proterozoic-Cambrian boundary and consist of quartzose sandstone with subordinate pebble conglomerate and siltstone. The Brigham Group is overlain by fossiliferous Cambrian carbonate units that represent the transition from siliciclastic to carbonate deposition in the Cordilleran miogeocline. The Brigham Group contains four stratigraphic sequences bounded by regional disconformities. The lower sequence includes strata below the Brigham group (upper member, Pocatello Formation), plus the Papoose Creek Formation and most of the overlying Caddy Canyon Quartzite. This sequence is dominantly marine with shoreface and braided fluvial strata at the top. The first sequence is overlain disconformably by offshore sub-wave base marine strata of the upper Caddy Canyon Quartzite and Inkom Formation. This second sequence is entirely marine and is composed dominantly of siltstone with sandstone-filled channels. The third sequence comprises the Mutual Formation, an entirely braided fluvial and lacustrine unit. The fourth sequence (Sauk sequence) locally overlies the Mutual Formation with an erosional unconformity and consists of dominantly marine strata of the Camelback Mountain Quartzite, Gibson Jack Formation, Windy Pass Argillite, Twin Knobs Formation, and Sedgwick peak Quartzite. Correlations of these sequences to the McCoy Creek Group of eastern Nevada suggests uniform conditions of sea level and subsidence across the late Proterozoic-Cambrian Cordilleran miogeocline. This preliminary synthesis suggests the Brigham and McCoy Creek Groups are post-rift deposits, as indicated by regional persistence of facies, paleocurrents, and quartzose petrology.

Link, P.K.; Jansen, S.T.; Halimdihardja, P.; Lande, A.C.; Zahn, P.D.

1987-08-01

121

Magnetic Fabric of the Aquidauana Formation, western border of the Paraná Basin Central Brazil: Preliminary Results  

NASA Astrophysics Data System (ADS)

The glaciogenic sedimentation (Carboniferous-Permian) on the western border of the Paraná Basin is represented by reddish-brown strata of the Aquidauana Formation. Subsurface data suggest that this Formation is equivalent to the Itararé Group, which contains the most extensive lithological record of Gondwana glaciation in the world. The Aquidauna Formation crops out as an NNE-SSW-oriented elongated belt at the western portion of the Maracaju-Campo Grande Plateau in Mato Grosso do Sul State (Central part of Brazil), and extents to the north up to Mato Grosso and Goias states. This Formation is composed of a variety of types of sandstones, siltites, and mudstones. The magnetic studies were performed on sites of undeformed reddish-brown sandstones, siltites, and mudstones, which crop out mainly in Mato Grosso do Sul State. Magnetic fabrics were determined on oriented cylindrical specimens (2.54 cm x 2.2 cm) using anisotropy of low-field magnetic susceptibility (AMS). Rock-magnetic analyses reveal that both magnetite and hematite are the main magnetic minerals in the majority of the analyzed sites. Regarding the eingenvector orientations, the sites usually gave good results. The analysis at the individual-site scale defines two AMS fabric types. The first type shows Kmin perpendicular to the bedding plane, while Kmax and Kint are scattered within the bedding plane itself. This fabric is usually interpreted as primary (sedimentary-compactional), typical of undeformed sediments and is dominant among the sites. The second type shows good clustering of the AMS principal axes with Kmin still either perpendicular or sub-perpendicular to the bedding plane. This fabric type could be interpreted as a combination of sedimentary-compactional and tectonic contributions if some strain markers or evidence for tectonic deformation had been found in the studied area. On the other hand, the tight Kmax grouping in this fabric type could be explained by the action of currents since they cause Kmax to be aligned sub-parallel to the paleocurrent direction.

Raposo, M. B.

2013-05-01

122

A preliminary assessment of sources of nitrate in springwaters, Suwannee River basin, Florida  

USGS Publications Warehouse

A cooperative study between the Suwannee River Water Management District (SRWMD) and the U.S. Geological Survey (USGS) is evaluating sources of nitrate in water from selected springs and zones in the Upper Floridan aquifer in the Suwannee River Basin. A multi-tracer approach, which consists of the analysis of water samples for naturally occurring chemical and isotopic indicators, is being used to better understand sources and chronology of nitrate contamination in the middle Suwannee River region. In July and August 1997, water samples were collected and analyzed from six springs and two wells for major ions, nutrients, and dissolved organic carbon. These water samples also were analyzed for environmental isotopes [18O/16O, D/H, 13C/12C, 15N/14N] to determine sources of water and nitrate. Chlorofluorocarbons (CCl3F, CCl2F2, and C2Cl3F3) and tritium (3H) were analyzed to assess the apparent ages (residence time) of springwaters and water from the Upper Floridan aquifer. Delta 15N-NO3 values in water from the six springs range from 3.94 per mil (Little River Springs) to 8.39 per mil (Lafayette Blue Spring). The range of values indicates that nitrate in the sampled springwaters most likely originates from a mixture of inorganic (fertilizers) and organic (animal wastes) sources, although the higher delta 15N-NO3 value for Lafayette Blue Spring indicates that an organic source of nitrogen is likely at this site. Water samples from the two wells sampled in Lafayette County have high delta 15N-NO3 values of 10.98 and 12.1 per mil, indicating the likelihood of an organic source of nitrate. These two wells are located near dairy and poultry farms, where leachate from animal wastes may contribute nitrate to ground water. Based on analysis of chlorofluorocarbons in ground water, the mean residence time of water in springs ranges from about 12 to 25 years. Chlorofluorocarbons-modeled recharge dates for water samples from the two shallow zones in the Upper Floridan aquifer range from 1985 to 1989.

Katz, B.G.; Hornsby, H.D.

1998-01-01

123

A Preliminary Investigation of the Yallalie Basin: A Buried 15 KM Diameter Structure of Possible Impact Origin in the Perth Basin, Western Australia  

Microsoft Academic Search

In late 1990, Ampol Exploration drew the attention of the senior author to an enigmatic structure located in Mesozoic rocks in the Dandaragan Trough of the Perth Basin about 200 km north of Perth, Western Australia. The basin-like Yallalie structure, centred on coordinates ca. 30 degrees 28'S, 115 degrees 47'E, is subcircular in plan view and about 15 km in

M. C. Dentith; A. W. R. Bevan; K. B. McInerney

1992-01-01

124

Isotopic monitoring (2H, 18O) of the St. Lawrence and Ottawa rivers between 1997 and 2003- Links with interannual climatic variability and hydrological processes in their catchment basins  

NASA Astrophysics Data System (ADS)

This study based on a water isotope (18O and 2H) monitoring of the St. Lawrence and Ottawa rivers (Canada) is a contribution to the international IAEA project: Isotopes tracing of hydrologic processes in large river basins [Gibson et al., 2002. EOS 83: 613 et p.]. Sampling of the St. Lawrence and Ottawa river waters started in 1997, on a biweekly to weekly basis. Monitoring stations are located at Montreal (i.e., at the outlet of the Great Lakes), Quebec City (the estuary of the St. Lawrence) and at the Carillon hydroelectric dam, near the outlet of a major tributary, the Ottawa River into the St. Lawrence itself. The goal of the study was to examine the seasonal and interannual variability of isotopic signatures of the St. Lawrence and Ottawa rivers, in relation notably with interannual climatic variations, and seasonal hydrologic processes in the watershed (summer evaporation, snowmelt, transit time of precipitation signals into runoff). Waters sampled at the three stations depict distinct isotopic compositions. At Montreal, relatively stable isotopic composition are observed with a mean weighted annual value of -54 % for 2H and -7.1 % for 18O. The Ottawa River water at Carillon also displays stable isotopic compositions but much lighter values (weighted mean annual values: -80 % for 2H and -10.8 % for 18O). Finally, isotopic compositions at Quebec City are intermediate between those of Montreal and Carillon, but show a much larger variability. They reflect mixing between the heavy isotope enriched Great Lakes water, the lighter water from the Ottawa River, and highly variable inputs from smaller tributaries (from the Laurentides and Appalachian mountains). The mean weighted isotopic compositions at Quebec City are -65 % and -8.6 %, respectively for 2H and 18O). Evaporative enrichment, in particular during low water level episodes, seem to be more important in the Ottawa River catchment than in the Great Lakes basin, based on a comparison of isotopic clusters at Montreal and Carillon (figure 1). Relatively strongly correlated relationships are observed between isotopic compositions at the estuary of the St. Lawrence River (Quebec) and hydrologic variables such as water discharge. The best fit follows the equation : 2HQUEBEC = -1.9E-03 * QQUEBEC - 41.9, R2= 0.59. Such a relationship leads us to conclude that some properties of the regional hydrology can be relatively well described by stable isotope systematics. In contradiction, air temperatures are not well correlated with isotopic signatures partly because of lag times between them in relation to transit time of precipitation signal into runoff. A comparison of isotopic values in precipitation to those of runoff gives an estimate of the mean transfer time of water from the catchment to the river estuary. For summer heavy isotope enriched, but scarcer precipitation, a transit time of approximately 3 months is observed, whereas in winter, it can be as long as 4 to 5 months due to the residence time of winter precipitation in the snowcover. The assessment of the interannual variability of the St. Lawrence River isotopic system will require a better estimate of the isotopic inprint from small tributaries (that drain isotopically buffered ground waters, particularly in winter). Data are presently at processing stage.

Myre, A.; Hillaire-Marcel, C.

2004-05-01

125

Design and development of a wireless sensor network to monitor snow depth in multiple catchments in the American River basin, California: hardware selection and sensor placement techniques  

NASA Astrophysics Data System (ADS)

A 100-node wireless sensor network (WSN) was designed for the purpose of monitoring snow depth in two watersheds, spanning 3 km2 in the American River basin, in the central Sierra Nevada of California. The network will be deployed as a prototype project that will become a core element of a larger water information system for the Sierra Nevada. The site conditions range from mid-elevation forested areas to sub-alpine terrain with light forest cover. Extreme temperature and humidity fluctuations, along with heavy rain and snowfall events, create particularly challenging conditions for wireless communications. We show how statistics gathered from a previously deployed 60-node WSN, located in the Southern Sierra Critical Zone Observatory, were used to inform design. We adapted robust network hardware, manufactured by Dust Networks for highly demanding industrial monitoring, and added linear amplifiers to the radios to improve transmission distances. We also designed a custom data-logging board to interface the WSN hardware with snow-depth sensors. Due to the large distance between sensing locations, and complexity of terrain, we analyzed network statistics to select the location of repeater nodes, to create a redundant and reliable mesh. This optimized network topology will maximize transmission distances, while ensuring power-efficient network operations throughout harsh winter conditions. At least 30 of the 100 nodes will actively sense snow depth, while the remainder will act as sensor-ready repeaters in the mesh. Data from a previously conducted snow survey was used to create a Gaussian Process model of snow depth; variance estimates produced by this model were used to suggest near-optimal locations for snow-depth sensors to measure the variability across a 1 km2 grid. We compare the locations selected by the sensor placement algorithm to those made through expert opinion, and offer explanations for differences resulting from each approach.

Kerkez, B.; Rice, R.; Glaser, S. D.; Bales, R. C.; Saksa, P. C.

2010-12-01

126

Modeling of facade leaching in urban catchments  

NASA Astrophysics Data System (ADS)

Building facades are protected from microbial attack by incorporation of biocides within them. Flow over facades leaches these biocides and transports them to the urban environment. A parsimonious water quantity/quality model applicable for engineered urban watersheds was developed to compute biocide release from facades and their transport at the urban basin scale. The model couples two lumped submodels applicable at the basin scale, and a local model of biocide leaching at the facade scale. For the facade leaching, an existing model applicable at the individual wall scale was utilized. The two lumped models describe urban hydrodynamics and leachate transport. The integrated model allows prediction of biocide concentrations in urban rivers. It was applied to a 15 km2urban hydrosystem in western Switzerland, the Vuachère river basin, to study three facade biocides (terbutryn, carbendazim, diuron). The water quality simulated by the model matched well most of the pollutographs at the outlet of the Vuachère watershed. The model was then used to estimate possible ecotoxicological impacts of facade leachates. To this end, exceedance probabilities and cumulative pollutant loads from the catchment were estimated. Results showed that the considered biocides rarely exceeded the relevant predicted no-effect concentrations for the riverine system. Despite the heterogeneities and complexity of (engineered) urban catchments, the model application demonstrated that a computationally "light" model can be employed to simulate the hydrograph and pollutograph response within them. It thus allows catchment-scale assessment of the potential ecotoxicological impact of biocides on receiving waters.

Coutu, S.; Del Giudice, D.; Rossi, L.; Barry, D. A.

2012-12-01

127

Inferring catchment precipitation by doing hydrology backward: A test in 24 small and mesoscale catchments in Luxembourg  

NASA Astrophysics Data System (ADS)

The complexity of hydrological systems and the necessary simplification of models describing these systems remain major challenges in hydrological modeling. Kirchner's (2009) approach of inferring rainfall and evaporation from discharge fluctuations by "doing hydrology backward" is based on the assumption that catchment behavior can be conceptualized with a single storage-discharge relationship. Here we test Kirchner's approach using a densely instrumented hydrologic measurement network spanning 24 geologically diverse subbasins of the Alzette catchment in Luxembourg. We show that effective rainfall rates inferred from discharge fluctuations generally correlate well with catchment-averaged precipitation radar estimates in catchments ranging from less than 10 to more than 1000 km2 in size. The correlation between predicted and observed effective precipitation was 0.8 or better in 23 of our 24 catchments, and prediction skill did not vary systematically with catchment size or with the complexity of the underlying geology. Model performance improves systematically at higher soil moisture levels, indicating that our study catchments behave more like simple dynamical systems with unambiguous storage-discharge relationships during wet conditions. The overall mean correlation coefficient for all subbasins for the entire data set increases from 0.80 to 0.95, and the mean bias for all basins decreases from -0.61 to -0.35 mm d-1. We propose an extension of Kirchner's approach that uses in situ soil moisture measurements to distinguish wet and dry catchment conditions.

Krier, R.; Matgen, P.; Goergen, K.; Pfister, L.; Hoffmann, L.; Kirchner, J. W.; Uhlenbrook, S.; Savenije, H. H. G.

2012-10-01

128

The contribution of sea-level rise to flooding in large river catchments  

NASA Astrophysics Data System (ADS)

Climate change is expected to both impact sea level rise as well as flooding. Our study focuses on the combined effect of climate change on upper catchment precipitation as well as on sea-level rise at the river mouths and the impact this will have on river flooding both at the coast and further upstream. We concentrate on the eight catchments of the Amazonas, Congo, Orinoco, Ganges/Brahmaputra/Meghna, Mississippi, St. Lawrence, Danube and Niger rivers. To assess the impact of climate change, upper catchment precipitation as well as monthly mean thermosteric sea-level rise at the river mouth outflow are taken from the four CCSM4 1° 20th Century ensemble members as well as from six CCSM4 1° ensemble members for the RCP scenarios RCP8.5, 6.0, 4.5 and 2.6. Continuous daily time series for average catchment precipitation and discharge are available for each of the catchments. To arrive at a future discharge time series, we used these observations to develop a simple statistical hydrological model which can be applied to the modelled future upper catchment precipitation values. The analysis of this surrogate discharge time series alone already yields significant changes in flood return levels as well as flood duration. Using the geometry of the river channel, the backwater effect of sea-level rise is incorporated in our analysis of both flood frequencies and magnitudes by calculating the effective additional discharge due to the increase in water level at the river mouth outflow, as well as its tapering impact upstream. By combining these effects, our results focus on the merged impact of changes in extreme precipitation with increases in river height due to sea-level rise at the river mouths. Judging from our preliminary results, the increase in effective discharge due to sea-level rise cannot be neglected when discussing late 21st century flooding in the respective river basins. In particular, we find that especially in countries with low elevation gradient, flood characteristics are impacted by changes in sea-level rise as far inland as 150 kilometers. Therefore, a larger population than the coastal inhabitants alone are exposed to risks of further projected increases of sea-level rise. A prime example for a megacity greatly put at risk by this is Dhaka City in Bangladesh, with a population of roughly 14 million people.

Thiele-Eich, I.; Hopson, T. M.; Gilleland, E.; Lamarque, J.; Hu, A.; Simmer, C.

2012-12-01

129

Sediment export by water from an agricultural catchment in the Loam Belt of central Belgium  

Microsoft Academic Search

An agricultural drainage basin of 250 ha was selected in the Belgian Loam Belt to evaluate sediment export by water. Water discharge was continuously measured at the outlet of the catchment and suspended sediment samples were taken proportional with discharge during rainfall events. From these samples supended sediment concentration and grain-size distribution were determined. Within the catchment, regular surveys were

A. Steegen; Gerard Govers; Jeroen Nachtergaele; Ingrid Takken; Laurent Beuselinck; Jean Poesen

2000-01-01

130

Global coastal segmentation and its river catchment contributors: A new look at land-ocean linkage  

Microsoft Academic Search

Here we present the COSCATs global database of 151 catchments in exorheic areas. The catchments connect to oceans through coastal segments according to three sets of criteria: natural limits (continents, oceans, regional seas, major capes, and bays), continental shelf topography (sills, basins, island chains), and geophysical dynamics (climate, ocean currents and tectonics). The COSCATs segmentation scheme is designed to improve

Michel Meybeck; Hans H. Dürr; Charles J. Vörösmarty

2006-01-01

131

Preliminary analysis of the role of lake basin morphology on the modern diatom flora in the Ruby Mountains and East Humboldt Range, Nevada, USA  

USGS Publications Warehouse

As paleolimnologists, we often look at the world through a 5-cm-diameter hole in the bottom of a lake, and although a number of studies have shown that a single core in the deepest part of a lake does not necessarily reflect the entire diatom flora, time and money often limit our ability to collect more than one core from a given site. This preliminary study is part of a multidisciplinary research project to understand Holocene climate variability in alpine regions of the Great Basin, and ultimately, to compare these high elevation records to the better studied pluvial records from adjacent valleys, in this case, the Ruby Valley.

Starratt, Scott W.

2014-01-01

132

PRELIMINARY DATA REPORT: HUMATE INJECTION AS AN ENHANCED ATTENUATION METHOD AT THE F-AREA SEEPAGE BASINS, SAVANNAH RIVER SITE  

SciTech Connect

A field test of a humate technology for uranium and I-129 remediation was conducted at the F-Area Field Research Site as part of the Attenuation-Based Remedies for the Subsurface Applied Field Research Initiative (ABRS AFRI) funded by the DOE Office of Soil and Groundwater Remediation. Previous studies have shown that humic acid sorbed to sediments strongly binds uranium at mildly acidic pH and potentially binds iodine-129 (I-129). Use of humate could be applicable for contaminant stabilization at a wide variety of DOE sites however pilot field-scale tests and optimization of this technology are required to move this technical approach from basic science to actual field deployment and regulatory acceptance. The groundwater plume at the F-Area Field Research Site contains a large number of contaminants, the most important from a risk perspective being strontium-90 (Sr-90), uranium isotopes, I-129, tritium, and nitrate. Groundwater remains acidic, with pH as low as 3.2 near the basins and increasing to the background pH of approximately 5at the plume fringes. The field test was conducted in monitoring well FOB 16D, which historically has shown low pH and elevated concentrations of Sr-90, uranium, I-129 and tritium. The field test included three months of baseline monitoring followed by injection of a potassium humate solution and approximately four and half months of post monitoring. Samples were collected and analyzed for numerous constituents but the focus was on attenuation of uranium, Sr-90, and I-129. This report provides background information, methodology, and preliminary field results for a humate field test. Results from the field monitoring show that most of the excess humate (i.e., humate that did not sorb to the sediments) has flushed through the surrounding formation. Furthermore, the data indicate that the test was successful in loading a band of sediment surrounding the injection point to a point where pH could return to near normal during the study timeframe. Future work will involve a final report, which will include data trends, correlations and interpretations of laboratory data.

Millings, M.

2013-09-16

133

Source rock potential and oil source correlation, Permian (Leonardian) strata, central Spraberry Trend, Midland basin, Texas - preliminary study  

Microsoft Academic Search

Wolfcampian-Leonardian sediments of the Midland basin comprise cyclic sequences of basinal terrigenous and carbonate mudstones overlain by terrigenous submarine-fan deposits. They have not undergone significant uplift, faulting, or water movement. Fractured sandstone and siltstone reservoirs of the Leonardian Spraberry Formation (lower and upper parts), having porosities of as much as 18% but generally less than 10% and permeabilities of less

E. H. Guevara; P. K. Mukhopadhyay

1987-01-01

134

Flash flood warning in mountainaious areas: using damages reports to evaluate the method at small ungauged catchments  

NASA Astrophysics Data System (ADS)

In Europe, flash floods mainly occur in the Mediterranean area on small catchments with a short concentration time. Anticipating this kind of events is a major issue in order to reduce the resulting damages. But for many of the impacted catchments, no data are available to calibrate and evaluate hydrological models. In this context, the aims of this study is to develop and evaluate a warning method for the Southern French Alps. This area is of particular interest, because it regroups different hydrological regimes, from purely Mediterranean to purely Alpine influences. Two main issues should be addressed: - How to define the hydrological model and its parameterization for an application in an ungauged context? - How to evaluate the final results on 'real' ungauged catchments? The first issue is a classic one. Using a 'observed' data set (154 streamflow stations with catchment areas ranging from 5 to 1000 km² and distributed rainfall available on the 1997-2006 period), we developed a regional model specifically for the studied area. For this purpose, the AIGA method, initially developed for Mediterranean catchments was adapted, in order to take into account snowmelt and to produce baseflows. Then, different parameterizations were tested, derived from different simple regionalisation techniques: - the same parameters set for the whole area defined as the median of the local calibrated parameters; - the same technique as the previous case, but by considering different sub-areas, defined as "hydro-climatically" homogeneous by previous studies; - and finally the neighbour's method. The second issue is more original. Indeed, in most studies the final evaluation is done using gauged stations as they were 'ungauged', ie keeping the at-site discharge data only for validation ant not for calibration. The main disadvantage of this approach is that the evaluation is made at the scale of the gauged catchments, which are in general greater than the catchments impacted by flash floods. Furthermore, many events are missed, since flash floods can occur very locally. In this study, we try to evaluate the results on observations collected by witnesses on 'real' ungauged catchments. The proposed method consists to use an historical data-base of flood damages reports. These data have been collected by local authorities (RTM). Finally, 139 ungauged locations were considered, where we simulated discharges for the entire 1997-2006 period. The comparison of these modelled discharges with the occurrence of an observed discharge makes it possible to determine a local 'modelled' discharge threshold above it most of the damages are observed. The pertinence of this threshold (and consequently of the model used for the simulation) is assessed by considering classical contingency statistics: probability of detection (POD), false alarm rate (FAR) and critical success index (CSI). The main advantage of this historical approach is the availability of many events in the database on very small catchments (50% less than 20 km²). The preliminary results show that on gauged basins, the base flow and the snowmelt added modules improve the performance of the AIGA method when locally calibrated. But when results are applied on real ungauged catchments, improvements become less obvious, with a small advantage for neighbour's method. These results shows the difficulty arising with ungauged catchments, specially when target catchments are smaller than the gauged 'parents'. It also illustrates the interest of the damages database used as 'proxy' data to investigate the model performances at smaller scales. This work has been done in the framework of the RHYTMME project, with the financial support of the European Union, the Provence-Alpes-Côte d'Azur Region and the French Ministry in charge of Ecology.

Defrance, Dimitri; Javelle, Pierre; Ecrepont, Stéphane; Andreassian, Vazken

2013-04-01

135

3d Geometry of The North Anatolian Fault System In The Cinarcik Basin: Preliminary Results (seismarmara 2001)  

NASA Astrophysics Data System (ADS)

The North Anatolian Fault (NAF) has been responsible for the last two earthquakes in Turkey (Izmit and Duzse, 1999). To the west, a seismic gap exists in the Marmara Sea, which is formed as series of pull apart basins along the NAF. Initial bathymetry and seismic reflection profiles show the presence of several faults on various scales in the Marmara Sea, from a few kilometers to tens of kilometers, in the three pull apart basins. The stress field (Coulomb) study suggests the possibility of a large earth- quake in this area, which could have a devastating effect on the region and on Istanbul, which is located only 10 km from north of the northern branch of NAF. In order to understand the earthquake activities in the Marmara Sea and image major seismogenic faults at depth, a combined seismic reflection, refraction and earthquake experiment was carried. Half of the 4000 km of deep seismic reflection profiles were acquired as a very detailed 3D grid survey at 600 m line spacing in the Cinarcik Basin, where NAF enters the Marmara Sea and bifurcates into two strands. On-board raw stacks show the presence of active faults down to 10 km in the basin. The 3D data provides a detailed 3D geometry of the NAF fault system in the Cinarcik basin, which suggests that it is an active NW-SE trending a kite-tail shaped pull-apart basin, with the two known strands of the NAF as its the long limbs. The relationship between the sedimentary strata, the basement and the faults provides insight on the evolution of basin. The ex- tensive set of faults along the southern limb suggests that this limb has played a key role in the evolution of the basin, from east to west. A small pull-apart basin at the corner of two adjoining faults in the south-west shows the role of a change in stress regime. A complex fault system in the Cinarcik basin suggests that is not a classical pull-apart basin, like the central basin, but may be representative of a basin at the tip of a long strike-slip fault, such as NAF. The 3D results will be discussed in the light of the formation and evolution of the whole Marmara Sea.

Singh, S.; Hirn, A.; de Voogd, B.; Vigner, A.; Bazin, S.; Charvis, P.; Géli, L.; Saatcilar, R.; Taymaz, T.; Ozalaybey, S.; Cetin, S.; Oçakoglu, N.; Ricolleau, A.; Karakoç, F.; Selvigen, V.

136

Preliminary assessment of channel stability and bed-material transport in the Rogue River basin, southwestern Oregon  

USGS Publications Warehouse

This report summarizes a preliminary assessment of bed-material transport, vertical and lateral channel changes, and existing datasets for the Rogue River basin, which encompasses 13,390 square kilometers (km2) along the southwestern Oregon coast. This study, conducted to inform permitting decisions regarding instream gravel mining, revealed that: * The Rogue River in its lowermost 178.5 kilometers (km) alternates between confined and unconfined segments, and is predominately alluvial along its lowermost 44 km. The study area on the mainstem Rogue River can be divided into five reaches based on topography, hydrology, and tidal influence. The largely confined, active channel flows over bedrock and coarse bed material composed chiefly of boulders and cobbles in the Grants Pass (river kilometers [RKM] 178.5-152.8), Merlin (RKM 152.8-132.7), and Galice Reaches (RKM 132.7-43.9). Within these confined reaches, the channel contains few bars and has stable planforms except for locally wider segments such as the Brushy Chutes area in the Merlin Reach. Conversely, the active channel flows over predominately alluvial material and contains nearly continuous gravel bars in the Lobster Creek Reach (RKM 43.9-6.7). The channel in the Tidal Reach (RKM 6.7-0) is also alluvial, but tidally affected and unconfined until RKM 2. The Lobster Creek and Tidal Reaches contain some of the most extensive bar deposits within the Rogue River study area. * For the 56.6-km-long segment of the Applegate River included in this study, the river was divided into two reaches based on topography. In the Upper Applegate River Reach (RKM 56.6-41.6), the confined, active channel flows over alluvium and bedrock and has few bars. In the Lower Applegate River Reach (RKM 41.6-0), the active channel alternates between confined and unconfined segments, flows predominantly over alluvium, shifts laterally in unconfined sections, and contains more numerous and larger bars. * The 6.5-km segment of the lower Illinois River included in this study was treated as one reach. This stretch of the Illinois River is fully alluvial, with nearly continuous gravel bars flanking the channel. The width of the active channel is confined by the narrow topography of the valley. * The primary human activities that have likely influenced channel condition, bed-material transport, and the extent and area of bars are (1) historical gold mining throughout the basin, (2) historical and ongoing gravel mining from instream sites in the Tidal Reach and floodplain sites such as those in the Lower Applegate River Reach, (3) hydropower and flow control structures, (4) forest management and fires throughout the basin, and (5) dredging. These anthropogenic activities likely have varying effects on channel condition and the transport and deposition of sediment throughout the study area and over time. * Several vertical (aspect) aerial photographs (including the complete coverages of the study area taken in 1995, 2000, 2005, and 2009 and the partial coverages taken in 1967, 1968, 1969, and 1990) are available for assessing long-term changes in attributes such as channel condition, bar area, and vegetation cover. A Light Detection And Ranging (LiDAR) survey performed in 2007-2008 provides 1-m resolution topographic data for sections of the Grants Pass (RKM 178.5-167.6) and Lobster Creek (RKM 17.8-12 and 10-6.7) Reaches and the entire Tidal Reach. * Previous studies provide information for specific locations, including (1) an estimated average annual bed-material load of 76,000 m3 at the former Savage Rapids Dam site (RKM 173.1, Grants Pass Reach), (2) over 490 m of channel shifting from 1965 to 1991 in the Brushy Chutes area (RKM 142-141, Merlin Reach), (3) active sediment transport and channel processes in the Lobster Creek Reach, (4) lateral channel migration in the Tidal Reach, and (5) up to 1.8 m of bar aggradation from the town of Agness (RKM 45.1) to the Rogue River mouth following the flood in water year 1997. * Review of the repeat surveys conducted at the instream gravel-mining sites on Elephant

Jones, Krista L.; O'Connor, Jim E.; Keith, Mackenzie K.; Mangano, Joseph F.; Wallick, J. Rose

2012-01-01

137

The Effect of Terrain Aspect on Interannual Variability of Hydrologic Response in Mountainous Catchments in New Mexico  

NASA Astrophysics Data System (ADS)

The aspect of the land surface in mid and high latitudes control hydrological response through differences in energy fluxes, prevailing winds, snow processes, evaporation and transpiration. In the Valles Caldera National Preserve (VCNP) in northern New Mexico, recent research has shown that north facing terrains accumulate thicker snow packs, the snow cover duration is longer, the soil moisture content is higher and hillslopes have longer water transit times. These findings suggest that catchments with a predominant north facing aspect are expected to have more water available and consequently a different hydrological response than catchments characterized by a different land orientation. This poster presents four years (2008-2011) of hydrological data in the VCNP and shows the hydrological response to interannual climate variability in mountainous catchments draining along different aspects. This investigation focuses on three perennial catchments draining Redondo Peak (3435m): La Jara (LJ; 3.67 km2), History Grove (HG; 2.42 km2) and Upper Jaramillo (UJ; 3.06 km2). The three catchments range in elevation between 2680 m and 3429 m. They share similar topographic characteristics, climate, vegetation and a complex geology. The most predominant north facing catchment is UJ; HG and LJ have both a predominant east facing aspect. This study is based on empirical observations of basin response and it has been carried out by way of monitoring physical amount, intensity and timing of water entering and leaving the catchments using the available meteorological data in the region and the instrumented network installed by the Jemez River Basin and Santa Catalina Mountains Critical Zone Observatory (http://www.czo.arizona.edu/). The climate in the region is semi-arid, continental and highly variable. For the water years (WY) 2008 and 2011 annual precipitation was 86% and 71% below the mean (P=711.5mm), and during WY 2009 and 2010, annual precipitation was 4% and 1% above the mean. Within the period of analysis the ratio of winter precipitation to annual precipitation varied from 59.4% to 39.4%. The maximum snow water equivalent (SWE) was equal to 303 mm and 53 mm during the years 2010 and 2011. Preliminary results show that the north facing catchment (UJ) had the highest annual discharge during the four years. Water yield (Q/P) for UJ was the highest and ranged between 0.10 during the driest year 2011 and 0.27 for the wettest year 2010. UJ shows the highest peak of specific discharge and it happens with a few days of delay with respect to the other catchments. UJ retains water for a longer time and it shows during dry and wet years the lowest variability between the flow percentiles Q15 and Q90 suggesting that north facing catchments are less susceptible to climate variability.

Zapata, X.; Troch, P. A.; McIntosh, J. C.; Broxton, P. D.; Brooks, P. D.

2012-12-01

138

Reframing water governance: a multi-perspective study of an over-engineered catchment in China  

Microsoft Academic Search

Climate change, over abstraction, pollution and questionable engineering-based paradigms are contributing to a state of crisis in water governance. This paper reports on preliminary research in Lake Baiyangdian catchment, China, which has the potential to realise more systemic and adaptive forms of water governance through development and use of a method that reframes water catchment management in the form of

Yongping Wei; Ray Ison; John Colvin; Kevin Collins

2012-01-01

139

Reframing water governance: a multi-perspective study of an over-engineered catchment in China  

Microsoft Academic Search

Climate change, over abstraction, pollution and questionable engineering-based paradigms are contributing to a state of crisis in water governance. This paper reports on preliminary research in Lake Baiyangdian catchment, China, which has the potential to realise more systemic and adaptive forms of water governance through development and use of a method that reframes water catchment management in the form of

Yongping Wei; Ray Ison; John Colvin; Kevin Collins

2011-01-01

140

How old is upland catchment water?  

NASA Astrophysics Data System (ADS)

Understanding the dynamics of water supply catchments is an essential part of water management. Upland catchments provide a continuous, reliable source of high quality water not only for some of the world's biggest cities, but also for agriculture and industry. Headwater streams control river flow in lowland agricultural basins as the majority of river discharge emerges from upland catchments. Many rivers are perennial and flow throughout the year, even during droughts. However, it is still unclear how reliable and continuous upland catchment water resources really are. Despite many efforts in upland catchment research, there is still little known about where the water is stored and how long it takes to travel through upper catchments. Resolving these questions is crucial to ensure that this resource is protected from changing land use and to estimate potential impacts from a changing climate. Previous research in this important area has been limited by existing measurement techniques. Knowledge to date has relied heavily on the use of variation in stable isotope signals to estimate the age and origin of water from upland catchments. The problem with relying on these measures is that as the water residence time increases, the variation in the stable isotope signal decreases. After a maximum period of four years, no variation can be detected This means that to date, the residence time in upland catchments is likely to have been vastly underestimated. Consequently, the proportion of water flow out of upland river catchments to the total river flow is also underestimated. Tritium (3H) combines directly with water molecules and enters the flow paths with the infiltrating water. Its half-life (12.32 years) makes it ideal to describe residence times in upper catchment reservoirs as it can theoretically measure water up to about 150 years old. The bomb pulse peak in the southern hemisphere was several orders of magnitude lower than in the northern hemisphere. Hence the Tritium activities in the southern hemisphere have long decayed down the natural background levels, which allows unique ages to be determined by single measurements. In this study major ion chemistry, stable isotopes and Tritium were determined at 2 locations and various stages of discharge (18 Tritium samples in between April 2013 and January 2014) in a first-order perennial stream draining a 7.3 km2 catchment in the Dandenong National Park, Melbourne, Australia. Even during major discharge event major ions and stable isotope data have little variation and Tritium activities remain low (1.4 to 1.8 TU) in comparison to local rainfall of ~ 3TU. Age estimations based on an exponential flow model are 15 to 25 years indicating that water draining from upland catchments is much older than we have previously estimated using stable isotopes.

Hofmann, Harald; Cartwright, Ian; Morgenstern, Uwe; Gilfedder, Benjamin

2014-05-01

141

WATER AND SEDIMENT MANAGEMENT FOR THE BLUE NILE BASIN  

Microsoft Academic Search

The sediment yield of rivers is often sensitive to changes in catchments land use and human activities. Such an impact is most likely to be demonstrated at a restricted spatial scale, particularly in headwater catchments. In large river basins such as Nile River Basin, there are needs to study, understand, and quantify the impacts of these modifications on the hydrologic

Tarek Mohamed Abdel-Aziz

2009-01-01

142

Nested Tracer Studies In Catchment Hydrology: Towards A Multiscale Understanding of Runoff Generation and Catchment Funtioning  

NASA Astrophysics Data System (ADS)

Geochemical and isotopic tracers have been shown to have widespread utility in catch- ment hydrology in terms of identifying hydrological source areas and characterising residence time distributions. In many cases application of tracer techniques has pro- vided insights into catchment functioning that could not be obtained from hydromet- ric and/or modelling studies alone. This paper will show how the use of tracers has contributed to an evolving perceptual model of hydrological pathways and runoff gen- eration processes in catchments in the Scottish highlands. In particular the paper will focus on the different insights that are gained at three different scales of analysis; (a) nested sub-catchments within a mesoscale (ca. 200 square kilometers) experimen- tal catchment; (b) hillslope-riparian interactions and (c) stream bed fluxes. Nested hydrometric and hydrochemical monitoring within the mesoscale Feugh catchment identified three main hydrological response units: (i) plateau peatlands which gener- ated saturation overland flow in the catchment headwaters, (ii) steep valley hillslopes which drain from the plateaux into (iii) alluvial and drift aquifers in the valley bottoms. End Member Mixing Analysis (EMMA) in 8 nested sub-catchments indicated that that stream water tracer concentrations can be modelled in terms of 2 dominant runoff pro- cesses; overland flow from the peat and groundwater from the drift aquifers. Ground- water contributions generally increased with catchment size, though this was moder- ated by the characteristics of individual sub-basins, with drift cover being particularly important. Hillslope riparian interactions were also examined using tracers, hydromet- ric data and a semi-distributed hydrological model. This revealed that in the glaciated, drift covered terrain of the Scottish highlands, extensive valley bottom aquifers effec- tively de-couple hillslope waters from the river channel. Thus, riparian groundwater appears to significantly contribute to storm runoff as well as sustain base flows. Water from steeper hillslopes appears to primarily recharge valley bottom aquifers. Fluxes from the drift aquifers into the stream bed were investigated using hydrometric and tracer techniques. Groundwater fluxes through the stream bed appear to be relatively localized relating to geological boundaries or changes in drift characteristics. How- ever, these fluxes are also controlled by morphological features in the river channel which exert a strong control on localized groundwater U surface water interactions. 1 If catchment hydrology is to contribute to a functional understanding of freshwater ecosystems it is argued that integrated tracer studies, at different scales and incorpo- rating both observations from field work and modelling applications, have a key role to play. 2

Soulsby, C.; Rodgers, P.; Malcolm, I. A.; Dunn, S.

143

Simulation of mine drainage for preliminary development of oil shale and associated minerals, Piceance basin, northwestern Colorado  

USGS Publications Warehouse

The Piceance basin of northwestern Colorado contains large resources of oil shale, nahcolite, and dawsonite. Development of these minerals will require drainage of water from mines. A six-layer hydrologic model of the basin was prepared to simulate mine drainage for mineral development. Streams and major tributaries were simulated as head-dependent nodes. Stream nodes were gaining or losing, but the rate of loss was constrained by the leakance of the streambed and the stream stage. Springs also were simulated as head-dependent nodes that stop flowing if the aquifer head declines below the spring orifice. (USGS)

Taylor, O. James

1986-01-01

144

Correlations between morphometric parameters and catchment wide denudation rates in catchments affected by crustal bending  

NASA Astrophysics Data System (ADS)

We analyzed the morphological parameters of catchments incising the Bolivian Altiplano and the Eastern Cordillera. The correlation of mean slopes and mean relief in the subbasins and their respective erosion rates are not instantly recognizable. However, there is a trend that the subbasins with high erosion rates are located close to the Cordillera, whereas subbasins with low erosion rates are located in immediate vicinity of the Altiplano. This observation led us to a more detailed analysis of the subbasins and their river networks in order to investigate the feedback mechanism between erosion rates and a surface morphology possibly affected by crustal response. Our test area, the La Paz drainage system is sourced on the very low relief Altiplano and links this region with the Subandean zone by cutting across the eastern high Cordillera. The catchment, with a total drainage area of 4850 km2, is shaped by a combination of feedback mechanisms involving erosion and crustal bending. Cross-cutting relationships between dated strata and incised valleys indicate that incision in the Rio La Paz headwaters postdates 2.8 Ma. The volume of about 3950 km3, which has been evacuated since then by the Rio La Paz drainage system to the Rio Beni relates to an average erosion rate of 290 mm/ky. This is in a similar range as the catchment-wide erosion rates determined by using terrestrial cosmogenic nuclides (TCN) derived from sediments being currently exported from the Rio La Paz basin. The method integrates for a timescales ranging from 1-10ky. Our results show an erosion rate of 230 mm/ky for the entire Rio La Paz basin (sample from basin outlet) and erosion rates from ca. 100 up to 600 mm/ky in the subbasins. In contrast, on the Altiplano west of the Rio La Paz drainage divide, erosion rates are one to two orders of magnitude lower than in the Rio La Paz catchment. We observed that the higher erosion rates correlate unexpectedly with a lower hypsometric integral for the subbasins in the Rio La Paz catchment. Further analysis concentrates on parameters derived from the channel network. Particularly parameters like Stream-gradient index (SL), Steepness index (ks) and Specific Stream Power (SSP) reveal the focus of erosion within the studied catchments. These spots of enhanced erosion coincide in general with the parts of the rivers, where mixed channel or bedrock incision is observed, and mainly where the channel length profiles show knickpoints. A spatial analysis of the geological properties detects those knickpoints induced by structures (faults and folds) and changes in lithology. We will demonstrate that the TCN results from the interior parts of the Rio La Paz catchments correlate only to certain extend with the surface morphology within the catchment. However, including the erosion rates and morphometric parameters from the catchments on the Altiplano, the correlation spanning data from both landscapes is obvious. This implies that the effects of feedback mechanisms between erosion and lithospheric deformation are substantial at the scale of individual structures, where flexural feedback mechanisms between erosion and rock uplift influences the morphometry of catchments and channel morphologies. When the dominant type of erosion processes (e.g. headwater expansion by landsliding and / or fluvial incision) is possibly influenced by tectonics then it can also cause the spatially variable erosion rates and different surface morphologies and consequently the partly inconclusive correlations.

Zeilinger, Gerold; Kober, Florian; Hippe, Kristina

2010-05-01

145

Preliminary selection of storm-water basins suitable for infiltration of reclaimed water in Nassau County, Long Island, New York  

USGS Publications Warehouse

A survey was made of 205 storm-water basins south of the ground-water divide and north of Hempstead Turnpike in Nassau County, Long Island, N.Y., to determine which would be best suited for infiltration of reclaimed water. Selection depended on infiltration area, location with respect to the ground-water divide and to planned transmission mains, tendency to retain storm runoff, underlying lithology, and depth to water table. The total maximum infiltration area of 14 selected basins is 60.2 acres, or 2,620,900 square feet (0.24 square kilometers). If 5-foot (1.5-meter) -high partitions were constructed in the basins to divide each into approximately equal halves and reclaimed water were applied in half of each basin to a depth of 5 feet (1.5 meters), using an application-rest cycle, a total area of 25.2 acres (0.10 square kilometers) would be available for supplemental recharge; the remaining infiltration area could be used for disposal of storm runoff. (Woodard-USGS)

Aronson, D.A.

1976-01-01

146

A preliminary evaluation of the CO 2 storage potential in unminable coal seams of the Münster Cretaceous Basin, Germany  

Microsoft Academic Search

The Münster Cretaceous Basin is a synclinal structure containing Upper Cretaceous sediments of local thickness exceeding 1700m, partially covered by Cenozoic deposits. The underlying basement consists of deep Carboniferous strata with interbedded hard coal seams. The Cretaceous sequence can be subdivided into the Cenomanian–Turonian-Complex, representing a brine aquifer, and the overlying ‘Emscher Mergel’ (clayey marl), separating the brine from shallow

Alexander Kronimus; Andreas Busch; Sascha Alles; Dierk Juch; Anke Jurisch; Ralf Littke

2008-01-01

147

Runoff processes, stream water residence times and controlling landscape characteristics in a mesoscale catchment: An initial evaluation  

Microsoft Academic Search

Tracer studies, using Gran alkalinity and ?18O, in nested sub-basins of the 230km2 Feshie catchment in the Cairngorm mountains, Scotland, were used to characterise hydrology in terms of groundwater contributions to annual runoff and mean residence times. Relationships between these fundamental hydrological descriptors and catchment characteristics were explored with the use of a GIS. Catchment soil distribution—mapped by the UK's

C. Soulsby; D. Tetzlaff; P. Rodgers; S. Dunn; S. Waldron

2006-01-01

148

A preliminary assessment of geodynamic controls on depositional systems and sandstone diagenesis in back-arc basins, Western Pacific Ocean  

NASA Astrophysics Data System (ADS)

Nine depositional systems are recognized in cores recovered by the Deep Sea Drilling Project from the back-arc basins of the western Pacific. These systems include: submarine fan, debris flow, silty basinal turbidite, biogenic pelagic carbonate, resedimented carbonate, biogenic pelagic silica, pyroclastic, hemipelagic and turbid-layer clay, and pelagic clay depositional systems. The occurrence of these depositional systems in time and space is correlated with regional uplift and volcanism, climatic change, biological productivity, and critical relations of sediment yield from potential sources which experience sufficient uplift and development of an extensive drainage and erosional regimen. Debris flows and submarine fan systems tend to accumulate after uplift of andesitic volcanic arc sources following development of a regional drainage network. Biogenic pelagic systems tend to be controlled by biological productivity and are indicators of back-arc basin movement through such productivity zones by regional crustal shift. Hemipelagic and turbid-layer clay systems are derived from terrigenous sources and their volume is dependent on climatically-controlled sediment yield from such sources. Resedimented carbonate systems tend to occur during times of active basinal faulting. Volcaniclastic sandstones recovered in back-arc basin DSDP cores show evidence of diagenetic alteration in response to burial depth, temperature and thermally-driven fluid circulation. Younger sandstones tend to show pore-space reduction, rim cementation by chlorite and mixed-layer illite-smectite and pore-filling cementation by clinoptilolite. Downhole, pores are filled with heulandite and analcite. Older sandstones show pore-filling with sparry calcite and replacement of component minerals and rock fragments by calcite, chert and zeolites. The distinct age-depth zonation of diagenetic changes suggests that thermally-driven interstitial fluids combined with advection of ocean waters and basement waters accounts best for the mineralogical reactions observed.

de Vries Klein, George; Yong Il Lee

1984-02-01

149

Development and Application of a Simple Hydrogeomorphic Model for Headwater Catchments  

EPA Science Inventory

We developed a catchment model based on a hydrogeomorphic concept that simulates discharge from channel-riparian complexes, zero-order basins (ZOB, basins ZB and FA), and hillslopes. Multitank models simulate ZOB and hillslope hydrological response, while kinematic wave models pr...

150

Evolution of Lake Chad Basin hydrology during the mid-Holocene: A preliminary approach from lake to climate modelling  

NASA Astrophysics Data System (ADS)

During the mid-Holocene (6000 yr Before Present, hereafter yr BP) the Chad Basin was occupied by a large endoreic lake, called Lake Mega-Chad. The existence of this lake at that time seems linked to increased monsoonal moisture supply to the Sahel and the Sahara, which in turn was probably ultimately caused by variations in the orbital forcing and higher temperature gradients between ocean and continent. This study provides a synthesis of several works carried out on the Lake Chad Basin and analyses the results of a simulation of the mid-Holocene climate with an Atmosphere General Circulation Model (LMDZ for Laboratoire de Météorologie Dynamique, IPSL Paris), with emphasis on the possible conditions leading to the existence of Lake Mega-Chad. The aim is to define the best diagnostics to understand which mechanisms lead to the existence of the large lake. This paper is the first step of an ongoing work that intends to understand the environmental conditions that this part of Africa experienced during the Upper Miocene (ca. 7 Ma BP), an epoch that was contemporaneous with the first known hominids. Indeed, early hominids of Lake Chad Basin, Australopithecus bahrelghazali [ Brunet, M., et al., 1995. The first australopithecine 2500 kilometers west of the Rift-Valley (Chad). Nature, 378(6554): 273-275] and Sahelanthropus tchadensis [Brunet, M., et al., 2002. A new hominid from the Upper Miocene of Chad, central Africa. Nature, 418(6894): 145-151; Brunet, M., et al., 2005. New material of the earliest hominid from the Upper Miocene of Chad. Nature, 434(7034): 752-755] are systematically associated with wet episodes that are documented for 7 Ma BP [Vignaud, P., et al., 2002. Geology and palaeontology of the Upper Miocene Toros-Menalla hominid locality, Chad. Nature, 418(6894): 152-155] and testified by extended lacustrine deposits (diatomites, pelites, various aquatic fauna). Because the mid-Holocene was the last such mega-lake episode, our aim here is to assess the simulated response of Lake Chad to the hydrologic changes caused by 6 kyr BP forcings (orbital variations, albedo, sea surface temperatures) as a test for a future use of the model for studies of the Miocene climate. We show that the induced northward shift of the simulated ITCZ, and the hydrological changes around the lake caused by this shift, are consistent with an increased water balance over the Lake Chad Basin 6000 yr ago. Water supply from the soil (runoff and river inputs) will have to be taken into account in further simulations in order to discuss the timing of the onset, expansion and decay of such a giant water surface in subtropical Africa.

Sepulchre, Pierre; Schuster, Mathieu; Ramstein, Gilles; Krinnezr, Gerhard; Girard, Jean-Francois; Vignaud, Patrick; Brunet, Michel

2008-03-01

151

The anthropic catchment-ecosystem concept: an Irish example  

SciTech Connect

The catchment-ecosystem concept is adapted to investigate the nutrient-budget of the highly-modified Colebrooke drainage basin in Northern Ireland. Anthropogenic inputs, mainly manures and fertilizers, account for 86% of the nitrogen and 96% of the phosphorus added to the catchment. These inputs greatly exceed the streamflow outputs, thereby indicating that the flow of nutrients is dominated by agriculture. This is explained by the transformation of traditional mixed farming into more intensive livestock production and is linked to policies encouraging increased agricultural production, amalgamation of farms, afforestation, rural depopulation, and urbanization. Substantial increases in the N and P output of the catchment and further eutrophication of the recipient lake, Lough Erne, are predicted without the implementation of policies to reduce agricultural nutrient losses.

Phillips-Howard, K.D.

1985-06-01

152

Analytical modeling of the hydrologic response under moving rainstorms: Storm-catchment interaction and resonance  

NASA Astrophysics Data System (ADS)

In this study, we propose a simple yet broad analytical framework for analyzing the hydrological response of a catchment under moving rainstorms; the method can be used as a tool to explore the main relevant features of the storm-catchment interactions. We analyze the response of the basin to an excess rain field (rain contributing to direct runoff), which is assumed to be variable in space and time; catchment response is supposed to be characterized by the time-invariant distribution of the travel time of water particles within the basin. We use the framework developed herein to investigate the conditions that enhance peak flow, leading to the so-called resonance effect, in terms of storm size, direction and velocity. Our results show how resonance conditions depend on the relative size of the rainstorm with respect to basin size. In particular, for storm sizes much smaller than the dimension of the catchment, a complete resonance effect occurs for infinite combinations of the direction and speed of the moving rainstorm. On the contrary, when storm size is much larger than the basin size, the flood peak tends to be independent on rainstorm movement. In the intermediate conditions a partial resonance effect emerges as a consequence of both the superposition of rainfall contributes in time and the increased flow response of the basin; the latter is a result of the larger rainfall volume injected over time. For illustration purposes, we present and discuss a case study based on the open-book idealized catchment.

Volpi, Elena; Di Lazzaro, Michele; Fiori, Aldo

2013-06-01

153

Climate change and hydrological response in a glaciated catchment in the Himalayas  

NASA Astrophysics Data System (ADS)

Hydrological effects of climate change on glaciated catchments are difficult to assess due to a poor representation of future glacial evolution in most models and the large heterogeneity of climate in areas with steep topography. We develop a spatial-dynamic hydrological model of the Langtang catchment (Nepal) at a spatial resolution of 90 meter that relates river runoff to precipitation and glacial melt processes. The model is forced by high resolution temperature and precipitation fields and at each daily time step precipitation is partitioned in either snow or rain. Part of the rain is routed along the digital elevation model (DEM) and leaves the catchment as rain runoff, while snow accumulates in the upstream parts of the basin and feeds the glaciers. Whereas previous hydrological studies adopt a simple degree day approach in combination with lumped glacier areas to quantify glacial melt, in this study the dynamic sliding of glaciers in the downstream direction is explicitly modeled. Glacier sliding is based on the shear stress with the bedrock and is evaluated on a pixel basis according to Weertman's sliding law. Glaciers only slide when the shear stress exceeds a threshold value that is derived using the slope of the terrain, local glacier thickness and assuming perfect plasticity of the ice. Each time step the sliding ice is transported down the digital elevation model and as temperature increases a degree day factor method is used to model ablation. The melt water is subsequently routed along the DEM. A two step calibration approach was used. Firstly, a 40 year period from 1960-2000 was simulated to calibrate the threshold shear stress, the degree day factor and the resistance of the bedrock using the observed glacier extent in 2000. Secondly, the rain runoff coefficient and base flow parameters were calibrated using observed daily discharges at the outlet of the catchment from 2000 to 2007. Results show that model is able to accurately simulate both the glacier extent using the 40 year time series and the discharge from 2000 to 2007. Based on precipitation and temperature change fields of the IPCC AR4 A1B scenario the effects of climate change on the hydrology are simulated. Preliminary results show that the glaciers withdraw significantly in the future, but that the reduction in melt water is compensated for by an increase in rain runoff. Given the fact that monsoon season coincides with the melt season no significant temporal shifts in the hydrograph occur and effects for downstream areas are likely to be limited. The innovative approach used to model the glaciers is highly suitable for climate change studies as it allows quantifying the future evolution of the glacier tongues dynamically without making assumptions on future glacier extent.

Immerzeel, Walter; van Beek, Ludovicus; Bierkens, Marc

2010-05-01

154

Long-term stable water isotope data from large river basins: preliminary analysis of the Global Network of Isotopes in Rivers (GNIR)  

NASA Astrophysics Data System (ADS)

In 2002 the International Atomic Energy Agency (IAEA) launched an international observation program for the collection and measurement of stable water isotopes and tritium in rivers. The Global network of Isotopes in Rivers (GNIR) now serves as a world-wide repository for contributed riverine isotope data, and expedites public dissemination of isotope data for water research purposes. Currently, the GNIR database contains about 21,000 stable water isotope records from 750 locations in 35 countries, in database format. Basic statistical descriptions are available for 252 observation sites that have isotope records for a minimum of two years. Here, we provide a summary of the GNIR stations established and the data compilations. Because the river locations are from different hydrological settings and climatic zones, the evaluation of the data gives a wide perspective of the global and temporal variations in the isotopic compositions of water in medium-size and large river basins. This synopsis reveals the useful application of stable water isotopes to assess the origin of water sources, mixing with precipitation, glacier and snow melt water, tributaries, the contribution of groundwater to baseflow, as well as, the impact of damming and irrigation return. In addition, the compiled isotope data give insights into temporal and spatial variations in the deuterium-excess and thereby provides independent information to estimate the relevance of evaporation in the water balance of large river basins. This preliminary analysis of the GNIR summarizes moreover, the experience gained from establishing large scale monitoring network stations and stable water isotope data collection within different environments. The GNIR program will be expanded and enhanced into the future with the addition of other biogeochemical isotopes, such as nutrients, particulate organic matter, and sediments. This will enhance gaining further scientific insights and information into water security and quality issues.

Halder, Janine; Terzer, Stefan; Wassenaar, Leonard, I.; Araguas-Araguas, Luis; Aggarwal, Pradeep

2014-05-01

155

Preliminary results of chronostratigraphic field work, OSL-dating and morphogenetic reconstruction of an alluvial apron at Alborz southern foothill, Damghan basin, Iran  

NASA Astrophysics Data System (ADS)

Here we present preliminary results of a chronostratigraphic study of an alluvial fan in the Damghan Basin, northern Iran. The basin sediments date back to the Mio- and Pliocene and therefore represent the starting point of alluvial fan aggradation. Today, the still active alluvial fans prograde from the Albors Mountain ranges and sit on the older sediment bodies. In this study, our focus is on the late Pleistocene to Holocene alluvial fan sedimentation history. The upper stratigraphy of the alluvial fans and intercalated lake deposits is characterized by six individual layers of gravels and fines, representing six different stratigraphic units. These units are described and classified by detailed geomorphological and stratigraphic mapping. To establish an alluvial fan chronology, six profiles were sampled for OSL dating. As expected, due to the high-energy transport system of alluvial fan aggradation in semi-desert environments, OSL dating of these sediments is challenging due to the problem of insufficient bleaching. Consequently, most of the samples are interpreted as maximum ages. However, the measurements show a consistent internal age structure and the overall OSL-based chronology is in agreement with the age model derived from our geomorphological analysis. As a first interpretation, based on surveyed geomorphological features and chronological analysis, we could identify seven morphodynamic phases, leading to a genetic model of alluvial fan aggradation. The oldest Pleistocene age estimate is derived from a former lake terrace. The following ages represent ongoing lake sediment deposition and the development of a proximal and mid-fan gravel cover. After the youngest lake deposits were accumulated within the Holocene, the lake starts to retreat and small alluvial fans are filling up the former lake bottom. This last sedimentation phase can be divided in at least two sub-phases, probably coupled to a lateral shifting of the active depositional lobe and to the abandonment and shallow incision of mid fan surfaces.

Büdel, Christian; Fuchs, Markus; Majid Padashi, Seyed; Baumhauer, Roland

2014-05-01

156

Structure of the Palomares margin from preliminary results of the TOPOMED-GASSIS seismic survey (Algero-Balearic basin, Western Mediterranean)  

NASA Astrophysics Data System (ADS)

We present two deep seismic reflection lines acquired during the TOPOMED-GASSIS seismic survey across the Palomares margin at the northwestern side of the Algero-Balearic basin. Simultaneously 3.5 kHz multi parametric echo-sounder profiles and bathymetric data were acquired, in order to obtain information of the most recent sedimentary/tectonic records, to relate tectonic structure with seafloor features and find out a possible tectonic control on them. The deep seismic reflection and the 3.5 kHz multi parametric echo-sounder profiles evidence anticlines and synclines affecting the Quaternary sediments. The southeastern limbs of the anticlines are cut by reverse faults suggesting a fault propagation origin for the folds. The recent to present character of these structures is confirmed by the congruence between structural and bathymetric highs and lows. Indeed, the submarine channels that cut across the margin are deflected by the folds flowing parallel to the major synclines, although cutting and incising into one of the anticlines. The folds have a N40-50°E orientation oblique to the Palomares active N20°E sinistral strike-slip fault zone. The data obtained from the TOPOMED-GASSIS seismic survey highlight the presence of contractive structures along the Palomares margin oriented perpendicular to the present NW-SE shortening stress field and according with the present GPS geodetic displacements. This preliminary result depicts a contractive Palomares margin where NW-SE shortening is accommodated by Quaternary NE-SW folds and thrusts. In the coastline and on land the shortening is also accommodated by reverse faults that cut both limbs of the Sierra Cabrera anticline. These faults and folds accommodate the sinistral displacement of the more northerly striking Palomares fault zone. Thus, the Palomares fault zone probably terminates close to the coast line to the south of the Vera basin by merging into these more northeasterly oriented structures. These folds probably nucleated upon previous extensional tilted blocks formed during the late Miocene development of the Algero-Balearic basin.

Giaconia, F.; Guzman Vendrell, M.; Booth-Rea, G.; Ranero, C. R.; Grácia, E.; Lo Iacono, C.

2012-04-01

157

Testing the Variable Source Area Hypothesis Using Tracers and GIS in an Nested Mesoscale Catchment  

NASA Astrophysics Data System (ADS)

Hydrometric and natural tracer investigations were combined with a GIS analysis of the 31km2 Girnock catchment (Cairngorm National Park, Scotland), to assess the significance of the variable source areas model in explaining dominant runoff process and mean residence times within the catchment. The catchment has a complex geology, soil cover and topographic organisation. Gran alkalinity was used to demonstrate that catchment geology has a dominant influence on baseflow chemistry, but low storm flow alkalinity indicated that flow paths originating in the acidic horizons in the upper profile of catchment soils dominated storm runoff generation. Chemically-based hydrograph separations at the catchment scale indicated that around 70% of annual runoff was derived from surface and near surface hydrological sources. Similar contributions (64-77%) were estimated for virtually all major sub-basins. delta18O ratios in precipitation (mean: -9.36, range: -16.10 to -5.02) and streamwaters (mean: -9.11, range: -11.65 to -7.42) were used to assess mean catchment and sub-basin residence times which were consistently in the order of 4-6 months. GIS analysis showed that these tracer-based diagnostic features of catchment functioning were consistent with the landscape organisation of the catchment. Soil maps derived from the UK HOST (Hydrology of Soil Type) data base indicated that the catchment as a whole, and individual sub-basins, were dominated by responsive soils such as Histosols and gleysols in valley bottom areas. Spatial analysis of soil cover - in combination with a catchment topographic index - predicted extensive areas of saturation in valley bottom areas that expand during hydrological events from return flow of hillslope groundwaters and direct precipitation generating saturation overland flow. Thus during storm events, a variable source area model agrees well with the high degree of hydrological connectivity between catchment hillslopes and the stream channel network. However, groundwater re-charge in the catchment is complex and characterised by much more marked heterogeneity than implied by the variable source area concept.

Tetzlaff, D.; Soulsby, C.; Waldron, S.; Malcolm, I.; Dunn, S.; Lilly, A.

2005-12-01

158

Framework to Calculate TMDL of Acid Mine Drainage For Cheat River Basin in West Virginia  

Microsoft Academic Search

The Watershed Analysis Risk Management Framework (WARMF) was enhanced to calculate the total maximum daily load (TMDL) of acid mine drainage for the Cheat River Basin in West Virginia. The framework divides the river basin into catchments, river segments, and lake layers. Some catchments have deep mines and\\/or surface mines. These catchments have a soil layer that contains pyrite (FeS2),

Carl W. Chen; Joel Herr; H. Z. Weintraub; Robert A. Goldstein; Rick Herd; J. M. Brown

159

Preliminary paleogeographic reconstruction of the Illinois basin during deposition of the Mississippian Aux Vases Formation: Implications for hydrocarbon recovery  

SciTech Connect

Extensive outcrop investigation and selective subsurface study allow definition of Illinois basin paleogeography during deposition of the Mississippian (Valmeyeran-Meramecian) Aux Vases Formation. The results incorporate an integrated approach utilizing field observations and petrographic analysis, wireline logs, subsurface maps, and cores. The Aux Vases Formation depositional system has been determined to be composed of subtidal to intertidal facies. Depositional facies in outcrop are based on rock body geometries, sedimentary structure assemblages, paleocurrent analysis, paleontology of body and trace fossils, facies relationships, and petrography. Depositional facies determined from subsurface data are based on correlation of lithologic interpretations from wireline logs, sand body geometries form isopach maps, and petrography. Specific depositional facies observed in outcrop and core and inferred from wireline logs and isopach maps are offshore bars and tidal channel complexes, extensive subtidal to lower intertidal, ripple-laminated, fine-grained quartzose sandstone. Carbonate facies occur as subtidal grainstones at or near the base of a sequence, or as high energy deposits which have been tidally reworked. This depositional system produces reservoir heterogeneities that complicate efficient hydrocarbon recovery. This diverse facies architecture is modified by tectonic and diagenetic overprinting, further segregating potential producing zones. To significantly improve recovery efficiency, predictions regarding compartmentalization can be used prior to designing a drilling program, an infill drilling program, or an application of enhanced recovery techniques.

Cole, R.D. (Illinois State Geological Survey, Champaign (United States))

1991-03-01

160

Study of rock-water-nuclear waste interactions in the Pasco Basin, Washington: Part II. Preliminary equilibrium-step simulations of basalt diagenesis  

SciTech Connect

Interactions between a large number of complex chemical and physical processes have resulted in significant changes in the Pasco Basin hydrochemical system since emplacement of the first basalt flow. In order to perform preliminary simulations of the chemical evolution of this system, certain simplifying assumptions and procedures were adopted and a computer model which operates on the principal of local equilibrium was used for the mass transfer calculations. Significant uncertainties exist in both the thermodynamic and reaction rate data which were input to the computer model. In addition, the compositional characteristics of the evolving hydrochemical system remain largely unknown, especially as a function of distance along the flow path. Given these uncertainties, it remains difficult to assess the applicability of the equilibrium-step approach even though reasonable matches between observed and simulated hydrochemical data were obtained. Given the uncertainties mentioned, the predictive abilities of EQ6 are difficult, if not impossible to evaluate; our simulations produced, at best, only qualitative agreement with observed product mineral assemblages and sequences, and fluid compositions.

Benson, L.V.; Carnahan, C.L.; Che, M.

1980-08-01

161

The relative influence of climate and catchment properties on hydrological drought  

NASA Astrophysics Data System (ADS)

Studying hydrological drought (a below-normal water availability in groundwater, lakes and streams) is important to society and the ecosystem, but can also reveal interesting information about catchment functioning. This information can later be used for predicting drought in ungauged basins and to inform water management decisions. In this study, we used an extensive Austrian dataset of discharge measurements in clusters of catchments and combine this dataset with thematic information on climate and catchment properties. Our aim was to study the relative effects of climate and catchment characteristics on drought duration and deficit and on hydrological drought typology. Because the climate of the region is roughly uniform, our hypothesis was that the effect of differences of catchment properties would stand out. From time series of precipitation and discharge we identified droughts with the widely-used threshold level approach, defining a drought when a variable falls below a pre-defined threshold representing the regime. Drought characteristics that were analysed are drought duration and deficit. We also applied the typology of Van Loon & Van Lanen (2012). To explain differences in drought characteristics between catchments we did a correlation analysis with climate and catchment characteristics, based on Pearson correlation. We found very interesting patterns in the correlations of drought characteristics with climate and catchment properties: 1) Droughts with long duration (mean and maximum) and composite droughts are related to catchments with a high BFI (high baseflow) and a high percentage of shallow groundwater tables. 2) The deficit (mean and maximum) of both meteorological droughts and hydrological droughts is strongly related to catchment humidity, in this case quantified by average annual precipitation. 3) The hydrological drought types that are related to snow, i.e. cold snow season drought and snow melt drought, occur in catchments that are have a high elevation, steep slopes, a high percentage of crystalline rock, bare rock and glacier. The conclusion of our research is that it is not straightforward to separate the effects of climate and catchment properties on drought, since they are interrelated. This is especially true for mountainous regions where temperature and precipitation are strongly dependent on altitude. We did however see that the duration of drought is more related to catchment storage (catchment properties) and the severity of drought (represented by the drought deficit) is more related to catchment wetness (climate). Van Loon, A.F., and Van Lanen, H.A.J.: A process-based typology of hydrological drought, Hydrology and Earth System Science, 16, p. 1915-1946, doi: 10.5194/hess-16-1915-2012, 2012

Van Loon, Anne; Laaha, Gregor; Koffler, Daniel

2014-05-01

162

Runoff predictions in ungauged catchments in southeast Tibetan Plateau  

NASA Astrophysics Data System (ADS)

The Tibetan Plateau (TP) plays a key role on both hydrology and climate for southern and eastern Asia. Improving runoff predictions in ungauged catchments in the TP is critical for surface water hydrology and water resources management in this region. However, a detailed runoff prediction study in this region has not been reported yet. To fill the gap, this study evaluates two regionalization approaches, spatial proximity and physical similarity, for predicting runoff using two rainfall-runoff models (SIMHYD and GR4J). These models are driven by meteorological inputs from eight large non-nested catchments (4000-50,000 km2) in the Yarlung Tsangpo River basin located in southeast TP. For each catchment, the two models are calibrated using data from the first two-thirds of the observation period and validated over the remaining period. The calibrated and validated Nash-Sutcliffe Efficiency of monthly runoff (NSE) varies from 0.73 to 0.93 for the SIMHYD model, and are similar to or slightly better than those obtained for the GR4J model. The incorporation of snowfall-snowmelt processes into the rainfall-runoff models does not noticeably improve the runoff predictions in the study area. The main reason is that monthly runoff is dominated by summer precipitation and snowfall in winter accounts for a small percentage (less than 14%). The results from both models show that the spatial proximity approach marginally outperforms the physical similarity approach and both approaches are better than random selection of a donor catchment. This is consistent with recent regionalization studies carried out in Europe and Australia. The study suggests that conceptual rainfall-runoff models are powerful and simple tools for monthly runoff predictions in large catchments in southeast TP, and incorporation of more catchments into regionalization can further improve prediction skills.

Li, Fapeng; Zhang, Yongqiang; Xu, Zongxue; Liu, Changming; Zhou, Yanchun; Liu, Wenfeng

2014-04-01

163

A preliminary investigation of the structure of southern Yucca Flat, Massachusetts Mountain, and CP basin, Nevada Test Site, Nevada, based on geophysical modeling  

Microsoft Academic Search

New gravity and magnetic data collected in the vicinity of Massachusetts Mountain and CP basin (Nevada Test Site, NV) provides a more complex view of the structural relationships present in the vicinity of CP basin than previous geologic models, helps define the position and extent of structures in southern Yucca Flat and CP basin, and better constrains the configuration of

Geoffrey A. Phelps; Leigh Justet; Barry C. Moring; Carter W. Roberts

2006-01-01

164

Preliminary analysis of water discharge and suspended sediment data from the Columbia River Basin: shifting rating curves and diminishing sediment loads  

NASA Astrophysics Data System (ADS)

Significant erosion along the coastlines of southwestern Washington in the last decade has motivated increased studies of sediment sources, sinks, and transport dynamics in the region. A key question is whether a reduction in sediment supply is responsible for the recent shift from a depositional regime. Because the Columbia River is the major fluvial system in the littoral cell, it is important to quantify sediment flux from the Columbia River to the coastal environment. We examine historical records of water discharge and suspended sediment transport along the Columbia main stem and in three subbasins in an attempt to quantify changes in total sediment transport and total load, and examine possible shifts in sediment sources over time. Suspended sediment data from the main stem near Vancouver, WA demonstrate a 3 to 5 fold downward shift in the rating curve in the last 90 years. The same trend is visible in data from the Snake River, with a decrease of almost an order of magnitude in sediment transport since the 1950's. Grain size data from the Kootenai River show a clear fining trend in the suspended load. The John Day River is the only long-term record we examined with no change in the rating curve over time; it is also the largest undammed river in the basin. Calculations of sediment load in the main stem were made using actual water discharge, estimated discharge (assuming no dams), and calculated `virgin' flow (Naik and Jay, in review). Preliminary results suggest that changes in the hydrograph (assuming a uniform rating curve) would diminish sediment transport to the coast by up to 20% over the last century; changes in the rating curve are responsible for at least that change, possibly more.

MacGregor, K. R.; Gelfenbaum, G.; Rubin, D.

2003-12-01

165

Patterns of Nitrate Export From two Hydrolgically Similar Catchments  

NASA Astrophysics Data System (ADS)

Recently there has been considerable interest in exploring how hydrologic flowpaths influence the export of solutes such as NO3- during hydrological events. The knowledge of flowpaths derived from TOPMODEL in combination with the potential solute source areas within the soil profile can be used to characterize the export of solutes. We explored the use of the topographic index (ln[a/tan B], where a is the upslope contributing area and B is the local slope) and field based measurements of soil water and groundwater to characterize surface water chemistry for two subcatchments of the Archer Creek catchment located in the Adirondack Mountains of NY. The two subcatchments are located in the headwaters of the catchment and have similar topography with steep slopes and incised streams, but marked differences in the magnitude of stream NO3- concentrations. We hypothesized that the temporal patterns in surface water concentrations of NO3- in stream water during hydrologic events will be similar between these two subcatchments and the relative contributions of deep verses shallow flow will be similar between the two catchments under a wide range of hydrologic regimes. Combining TOPMODEL predictions of flow contributions with predictions of concentrations of solutes in different hydrologic reservoirs over hydrological events was used to model the evolution of solutes in these subcatchments. Preliminary results have suggested that temporal patterns in stream water chemistry are similar between the catchments. Thus differences in the magnitude of stream NO3- concentrations can be attributed to the relative amounts of NO3- generated in the surface soil of each subcatchment. The catchment with higher NO3- has an overstory vegetation that is associated with high rates of N mineralization and nitrification in the Adirondack region. Despite these differences in the magnitude of NO3- concentrations, the hydrological responses of each subcatchment are similar suggesting that there are no substantial differences in flowpaths between the two catchments.

Christopher, S. F.; Mitchell, M. J.; Inamdar, S.; Page, B. D.

2002-12-01

166

Temporal buffering of climate-driven sediment flux cycles by transient catchment response  

NASA Astrophysics Data System (ADS)

The marine sedimentary record can exhibit a systematic cyclicity that is consistent with climate variability driven by Milankovitch-scale forcing. Milankovitch-band cyclicity is widely interpreted in the hemipelagic and pelagic sediments of the marine realm, and in terrestrial paleoenvironments has been observed in lacustrine sediments, soils and river floodplain successions. It remains unclear, however, if and how mountain catchments, as a primary sediment source, respond to these high frequency (<106 yr) climatic cycles, and whether particulate sediment flux signals can be expected to be recorded in the clastic sedimentary record of adjacent basin-fills. Recent field and theoretical studies suggest that mountain catchments respond transiently to high frequency forcing, and so sediment discharge from the catchment is a non-linear function of forcing variables. Using a catchment-basin model, we demonstrate that climate-driven cyclicity in particulate sediment discharge is strongly damped when the period of climate variability is shorter than the response timescale of the eroding landscape. Given that the response timescale of landscapes is of the order of 106 yr, and that Milankovitch-driven climate cyclicity is of the order of 104-105 yr, it is likely that climate-driven perturbation of upland catchments at these periods will be strongly damped by transient landscape behaviour. Our results therefore suggest that stratigraphy built by particulate fluxes from upland catchments, and long-term trends in the sediment delivery to the ocean, may be relatively insensitive to short-term climate variability.

Armitage, John J.; Dunkley Jones, Tom; Duller, Robert A.; Whittaker, Alexander C.; Allen, Philip A.

2013-05-01

167

A Preliminary Investigation of The Structure of Southern Yucca Flat, Massachusetts Mountain, and CP Basin, Nevada Test Site, Nevada, Based on Geophysical Modeling  

USGS Publications Warehouse

New gravity and magnetic data collected in the vicinity of Massachusetts Mountain and CP basin (Nevada Test Site, NV) provides a more complex view of the structural relationships present in the vicinity of CP basin than previous geologic models, helps define the position and extent of structures in southern Yucca Flat and CP basin, and better constrains the configuration of the basement structure separating CP basin and Frenchman Flat. The density and gravity modeling indicates that CP basin is a shallow, oval-shaped basin which trends north-northeast and contains ~800 m of basin-filling rocks and sediment at its deepest point in the northeast. CP basin is separated from the deeper Frenchman Flat basin by a subsurface ridge that may represent a Tertiary erosion surface at the top of the Paleozoic strata. The magnetic modeling indicates that the Cane Spring fault appears to merge with faults in northwest Massachusetts Mountain, rather than cut through to Yucca Flat basin and that the basin is downed-dropped relative to Massachusetts Mountain. The magnetic modeling indicates volcanic units within Yucca Flat basin are down-dropped on the west and supports the interpretations of Phelps and KcKee (1999). The magnetic data indicate that the only faults that appear to be through-going from Yucca Flat into either Frenchman Flat or CP basin are the faults that bound the CP hogback. In general, the north-trending faults present along the length of Yucca Flat bend, merge, and disappear before reaching CP hogback and Massachusetts Mountain or French Peak.

Phelps, Geoffrey A.; Justet, Leigh; Moring, Barry C.; Roberts, Carter W.

2006-01-01

168

Changes in catchment hydrology in relation to vegetation recovery: a comparative modelling experiment  

NASA Astrophysics Data System (ADS)

Mediterranean mountains have been largely affected by land abandonment and subsequent vegetation recovery, with a general expansion of shrubs and forests. Such a large scale land-cover change has modified the hydrological behavior of these areas, with significant impact on runoff production. Forecasting the trend of water resources under future re-vegetation scenarios is of paramount importance in Mediterranean basins, where water management relies on runoff generated in these areas. With this purpose, a modelling experiment was designed based on the information collected in two neighbouring research catchments with a different history of land use in the central Spanish Pyrenees. One (2.84 km2) is an abandoned agricultural catchment subjected to plant colonization and at present mainly covered by shrubs. The other (0.92 km2) is a catchment covered by dense natural forest, representative of undisturbed environments. Here we present the results of the analysis of the hydrological differences between the two catchments, and a description of the approach and results of the modelling experiment. In a statistical analysis of the field data, significant differences were observed in the streamflow response of the two catchments. The forested catchment recorded fewer floods per year compared to the old agricultural catchment, and its hydrological response was characterised by a marked seasonality, with autumn and spring as the only high flow periods. Stormflow was generally higher in the old agricultural catchment, especially for low to intermediate size events; only for large events the stormflow in the forested catchment was sometimes greater. Under drier conditions, the relative differences in the stormflow between the two catchments tended to increase whereas under wet conditions they tended to be similar. The forested catchment always reacted more slowly to rainfall, with lower peakflows (generally one order of magnitude lower) and longer recession limbs. The modelling experiment aims at separating the effect of land cover from other differences (e.g. catchment area, morphology) between the two catchments. This approach allows us to make general statements on effects of land cover, required for future predictions for larger areas. In our modelling experiment, a process-based distributed hydrological model is used for the two catchments. First, we calibrate the model using data from the two catchments until a single set of parameters valid for both is found. With this set of parameters and considering a given meteorological driver (due to their proximity, it can be considered the same for both catchments), runoff at the outlet of each catchment is simulated. Land cover is then swapped between catchments and a new runoff simulation is performed for each "swapped" catchment, using the same set of parameters and the same meteorological driver. The effects of the land cover change are determined by analysing the differences between the first and the "swapped" simulations. This study is based on an analysis of the hydrological differences of two catchments with different history of land use, and a comparative modelling experiment applied to them. Following this approach, we attempt to advance our understanding of the effects of land-use/land-cover changes in catchment hydrology and, ultimately, anticipate their hydrological consequences under a future re-vegetation scenario.

Lana-Renault, Noemí; Karssenberg, Derek; Latron, Jérôme; Serrano, M? Pilar; Regüés, David; Bierkens, Marc F. P.

2010-05-01

169

Source and transport factors influencing storm phosphorus losses in agricultural catchments  

NASA Astrophysics Data System (ADS)

The relative risk of diffuse phosphorus (P) loss from agricultural land was assessed in a well-drained arable catchment and a poorly-drained grassland catchment and in two nested basins within each catchment. This research investigated the relative control of hydrology and soil P on P losses between basins. Quick flow (QF) P losses (defined here as both concentrations and loads), monitored in stream flow during four storm events, were compared with a dynamic metric of transport risk (QF magnitude) and a static metric of critical source area (CSA) risk (extent of highly-connected poorly-drained soils with excess plant-available soil P). The potential for static transport metrics of soil connectivity and soil drainage class, to predict relative QF magnitudes and P losses between basins was also investigated. In basins with similar CSA risk but with contrasting QF magnitudes, mean TRP (total molybdate-reactive P) losses were consistently higher in the basins which had the highest QF magnitudes. This suggests that basin hydrology, rather than hydrology of high-P soils only, determined relative TRP losses between hydrologically contrasting basins. Furthermore, static transport metrics of soil connectivity and soil drainage class reliably discerned relative QF magnitudes and TRP losses between these basins. However, for two of the storm events (both occurring during the hydrologically active season), PP (particulate P) concentrations were frequently higher in basins which had the lowest QF magnitudes and may be attributed to a higher proportion of bare soil in these basins at these times as a result of their predominantly arable nature. In basins with similar hydrology, relative TRP and PP losses did not reflect trends in CSA risk or QF magnitude. The dynamics of TRP and PP losses and QF magnitude between these basins varied across storms, thus could not be predicted using static metrics. Where differences in hydrological dynamics were large, storm TRP losses were well differentiated by dynamic or static transport metrics alone, regardless of differences in soil P. Where hydrological dynamics were similar, non-static transport metrics and P source information additional to soil P, may be required to differentiate the relative risk of storm TRP in these agricultural catchments. Regardless of differences in hydrological dynamics, information on land use and management, such as time of ploughing, may be required to differentiate the relative risk of PP loss in these agricultural catchments.

Shore, Mairead; Jordan, Phil; Mellander, Per-Erik; kelly-quinn, Mary; Wall, David; Murphy, Paul; Melland, Alice

2014-05-01

170

The EU Water Framework Directive--a key to catchment-based governance.  

PubMed

The principles of good water governance require an effective water policy with a clear legal framework and institutional structure for managing river basins and aquifers. Integrated water resources management is essential and decision-making processes must be participatory and transparent. The development of the European Union's Water Framework Directive is outlined, and it is shown how it can serve as the basis of catchment-based governance for the successful management of water quality and quantity in transboundary river basins. PMID:12019807

Holzwarth, Fritz

2002-01-01

171

Old groundwater influence on stream hydrochemistry and catchment response times in a small Sierra Nevada catchment: Sagehen Creek, California  

USGS Publications Warehouse

[1] The relationship between the chemical and isotopic composition of groundwater and residence times was used to understand the temporal variability in stream hydrochemistry in Sagehen basin, California. On the basis of the relationship between groundwater age and [Ca2+], the mean residence time of groundwater feeding Sagehen Creek during base flow is approximately 28 years. [Cl-]:[Ca2+] ratios in Sagehen Creek can be used to distinguish between two important processes: changes in the apparent age of groundwater discharging into the creek and dilution with snowmelt. The mean residence time of groundwater discharging into the creek is approximately 15 years during snowmelt periods. The results from this study have implications for hydrograph separation studies as groundwater is not a single, well-mixed chemical component but rather is a variable parameter that predictably depends on groundwater residence time. Most current models of catchment hydrochemistry do not account for chemical and isotopic variability found within the groundwater reservoir. In addition, this study provides valuable insight into the long-term hydrochemical response of a catchment to perturbations as catchment-flushing times are related to the mean residence time of water in a basin. Copyright 2005 by the American Geophysical Union.

Rademacher, L. K.; Clark, J. F.; Clow, D. W.; Hudson, G. B.

2005-01-01

172

Geomorphic (de-) coupling of hillslope and channel systems within headwater catchments in two subarctic tributary valleys, Nordfjord, Western Norway  

NASA Astrophysics Data System (ADS)

Hillslopes occupy large areas of the earth surface. Studying the characteristics, development and interaction of hillslopes as components of the geomorphic hillslope-channel coupling process-response system will improve the understanding of the complex response of mountain landscape formation. The rates of hillslope processes are exceptionally varied and affected by many influences of varying intensity. Hillslope-channel coupling and sediment storage within slopes are important factors that influence sediment delivery through catchments, especially in steep environments. Within sediment transfers from sources to sinks in drainage basins, hillslopes function as a key element concerning sediment storage, both for short term periods as between rainstorms as well as for longer periods in colluvial deposits. This PhD project is part of the NFR funded SedyMONT-Norway project within the ESF TOPO-EUROPE SedyMONT (Timescales of sediment dynamics, climate and topographic change in mountain landscapes) programme. The focus of this study is on geomorphic hillslope-channel coupling or de-coupling and sediment transport within four distinct headwater areas of the Erdalen and Bødalen catchments in the Nordfjord valley-fjord system (inner Nordfjord, Western Norway). Both catchments can be described as steep, U-shaped and glacier-fed, subarctic tributary valleys. Approximately 14% of the 49 km2 large headwater area of Erdalen is occupied by hillslope deposits; in Bødalen hillslope deposits occupy 12% of the 42 km2 large headwater area. The main aims of the study are to present preliminary findings on (i) the identification of possible sediment sources and delivery pathways within the headwater areas of the catchments, (ii) to analyze the development of hillslope-channel coupling / de-coupling from postglacial to contemporary timescales as well as (iii) to investigate the current degree of geomorphic hillslope-channel coupling within the different headwater catchments and (iv) to determine differently acting mass movement processes. A process-based approach is applied to assess the importance of hillslope sediment production, storage and transport throughout the catchments, including orthophoto-interpretation, hillslope profile surveying, photo monitoring, geomorphological mapping, GIS and DEM computing as well as a combination of different field techniques for bed load monitoring. Appropriate hillslope test sites within the headwater catchments are selected in order to fulfill the main aims of this study as well as to monitor contemporary rates of hillslope fluxes. The designed monitoring instrumentation of the slope test sites includes nets, stone tracer lines, wooden sticks, peg lines, slop wash traps and remote site monitoring cameras. Hillslope profile surveying, geomorphological mapping and measurements of solute yields from the slope systems are carried out at each test site. Channel longitudinal- and cross profiles are measured in defined test stretches of the first order streams, located downhill of the slope test sites. Within the same channel test stretches extensive pebble counts (grain size, grain shape) are conducted seasonally and tracer lines are installed in order to trace different bed load components. The four selected headwater areas are characterized by different intensities of hillslope-channel coupling, mainly due to the distinct valley morphometries affected by the glacial inheritance of the Nordfjord region. Where hillslope-channel coupling exists, primary coarse material is delivered from the hillslopes into the channels via snow avalanches. These coarse grained and angular components can be traced within the channel test stretches. Research on the complex evolution of hillslope-channel (de-) coupling over time and contemporary sediment transfer fluxes contributes to a better understanding of possible trends of mountain landscape development.

Laute, Katja; Beylich, Achim A.

2010-05-01

173

Estimation of natural pollution loads from streamflow measurements in remote catchments  

Microsoft Academic Search

In a study conducted in Marmot Creek Basin (total area 9.40 kmz) situated in the Rocky Mountains of Alberta, equations were developed to obtain gross estimates of the total inorganic solutes dislodged from three forest catchments on a monthly and annual basis. The r2 range of the equations was 99% or greater, indicating excellent fit in all cases. The equations

Teja Singh; Y. P. Kalra

1977-01-01

174

Nonparametric method for estimating the effects of climatic and catchment characteristics on mean annual evapotranspiration  

NASA Astrophysics Data System (ADS)

It is now well known that forested catchments have higher evapotranspiration than grassed catchments. Models for mean annual evapotranspiration have been developed to quantify catchment scale differences in mean annual evapotranspiration. Zhang et al. (2001) developed a simple, one parameter, model for the relationships between evapotranspiration and vegetation cover by evaluating the differences of model parameter values for different vegetation covers. However, other factors such as climate and catchment topography may also affect evapotranspiration and therefore the model parameter. Simple models acknowledging only categorical vegetation cover (forested, mixed, and grassed) may introduce some uncertainty, and more seriously, lead to inconsistent conclusions regarding relationships between vegetation cover and evapotranspiration. Zhang et al. (2004) investigated possible inclusion of climatic factors and catchment characteristics to improve the estimation of mean annual evapotranspiration by modeling the residuals of the model parameter via a stepwise linear regression. In this paper we propose the use of a multivariate adaptive regression spline (MARS) model for estimating the model parameter. In contrast to a simple stepwise regression, the MARS model provides not only insight into the interactions between explanatory factors but also a potential for prediction for ungauged basins as long as the values of explanatory factors are within the domain of calibration catchments. The MARS model is able to determine statistically significant factors and therefore is a powerful tool to identify important factors and their interactions. Using 241 Australian catchments where climate factors and catchment characteristics are available, we found the following significant terms affecting the mean annual evapotranspiration. (1) The functional relationship with the number of months that peak precipitation follows peak potential evapotranspiration (PfE) states that closer phase between precipitation and potential evapotranspiration results in less streamflow. (2) The interactions between coefficient of variation of precipitation and average storm depth shows that the value of the model parameter is smaller when the coefficient of variance of precipitation is larger than 2.24 and the average storm depth is less than 8.70 mm d-1. (3) The interaction between relief ratio and average storm depth term shows that both larger average storm depth in flat catchments and smaller average storm depth in hilly catchments result in more streamflow. (4) The interaction between relief ratio and forest coverage reveals that for flat catchments with reasonable forest cover, increasing forest cover generally results in more mean annual evapotranspiration and less mean annual streamflow. The performance of the MARS model was assessed by a calibration-testing procedure to support its usage for prediction for ungauged basins.

Shao, Quanxi; Traylen, Anthony; Zhang, Lu

2012-03-01

175

Assessing catchment hydrological functioning using discharge recession analysis based on the Kirchner's method. A case study in the Ardèche catchment (France)  

NASA Astrophysics Data System (ADS)

Catchments show a high degree of heterogeneity and variability, both in space and time. In order to deal with spatial heterogeneity and process variability in more efficient and more "natural and realistic" manner, model simplifications are needed. Governing equations such as the Darcy or Richards' equation, which are inherent in many hydrological models, are suitable for local scales. However, their application at much larger scales (e.g. catchment scale) remains problematic. The linear reservoir is a well-known and common approach in many catchment-based hydrological models. However, reality shows that those linear equations might not be representative enough for describing hydrological catchment behavior. Kirchner (2009), proposed a simple approach representing catchment behavior as a non-linear reservoir model, assuming that discharge at the outlet is only a function of catchment storage. He also proposed a method to determine non-linear reservoir parameters for this simple bucket model. The objective of this study is to investigate whether this approach is applicable to the Ardèche catchment (2355 km2), located in the southern part of France. The catchment is influenced by a Mediterranean climate with seasonal heavy rainfall events during autumn. The northern and north-western part of the catchment is characterized by steep slopes and igneous and metamorphic rock formations. A further objective is to relate the estimated parameters of the first-order dynamical system to catchment characteristics, in order to be able to develop a distributed model, adapted to the catchment response variability. The challenge for the Kirchner's method is the high geological and pedological heterogeneity of the Ardèche basin. We apply the Kirchner's method to 6 sub-catchments of the Ardèche ranging from 3.9 to 200 km2 using hourly rainfall and discharge data, in order to identify the discharge sensitivity function. We use the obtained corresponding parameters in a simple bucket model similar to the one proposed by Kirchner (2009). To have more representative potential evapotranspiration data used in the model, we introduce crop coefficient seasonality to better represent the data. Performance measurements with the Nash-Sutcliffe coefficient show performances above 80 %. These results clearly indicate that timing and magnitude of simulated discharge is correctly reproduced by the model. Additionally we assess the impact of the seasonality on the model parameterization yielding similar results in the discharge analysis. Our work shows that Kirchner's method can be applied successfully in the Ardèche catchment. Eventually, we observe that geology may be highlighted as a predictor that dominates the overall hydrological response in the basin. Kirchner, J. W. (2009), Catchments as simple dynamical systems: Catchment characterization, rainfall-runoff modeling, and doing hydrology backward, Water Resour. Res., 45, W02429, doi:10.1029/2008WR006912

Adamovic, Marko; Braud, Isabelle; Branger, Flora; Krier, Robert

2013-04-01

176

Transit times of water particles in the vadose zone across catchment states and catchments functional units  

NASA Astrophysics Data System (ADS)

Understanding the water movement in the vadose zone and its associated transport of solutes are of major interest to reduce nutrient leaching, pollution transport or other risks to water quality. Soil physical models are widely used to asses such transport processes, while the site specific parameterization of these models remains challenging. Inverse modeling is a common method to adjust the soil physical parameters in a way that the observed water movement or soil water dynamics are reproduced by the simulation. We have shown that the pore water stable isotope concentration can serve as an additional fitting target to simulate the solute transport and water balance in the unsaturated zone. In the presented study, the Mualem- van Genuchten parameters for the Richards equation and diffusivity parameter for the convection-dispersion equation have been parameterized using the inverse model approach with Hydrus-1D for 46 experimental sites of different land use, topography, pedology and geology in the Attert basin in Luxembourg. With the best parameter set we simulated the transport of a conservative solute that was introduced via a pulse input at different points in time. Thus, the transit times in the upper 2 m of the soil for different catchment states could be inferred for each location. It has been shown that the time a particle needs to pass the -2 m depth plane highly varies from the systems state and the systems forcing during and after infiltration of that particle. Differences in transit times among the study sites within the Attert basin were investigated with regards to its governing factors to test the concept of functional units. The study shows the potential of pore water stable isotope concentration for residence times and transport analyses in the unsaturated zone leading to a better understanding of the time variable subsurface processes across the catchment.

Sprenger, Matthias; Weiler, Markus

2014-05-01

177

Preliminary assessment of channel stability and bed-material transport in the Tillamook Bay tributaries and Nehalem River basin, northwestern Oregon  

USGS Publications Warehouse

This report summarizes a preliminary study of bed-material transport, vertical and lateral channel changes, and existing datasets for the Tillamook (drainage area 156 square kilometers [km2]), Trask (451 km2), Wilson (500 km2), Kilchis (169 km2), Miami (94 km2), and Nehalem (2,207 km2) Rivers along the northwestern Oregon coast. This study, conducted in coopera-tion with the U.S. Army Corps of Engineers and Oregon Department of State Lands to inform permitting decisions regarding instream gravel mining, revealed that: * Study areas along the six rivers can be divided into reaches based on tidal influence and topography. The fluvial (nontidal or dominated by riverine processes) reaches vary in length (2.4-9.3 kilometer [km]), gradient (0.0011-0.0075 meter of elevation change per meter of channel length [m/m]), and bed-material composition (a mixture of alluvium and intermittent bedrock outcrops to predominately alluvium). In fluvial reaches, unit bar area (square meter of bar area per meter of channel length [m2/m]) as mapped from 2009 photographs ranged from 7.1 m2/m on the Tillamook River to 27.9 m2/m on the Miami River. * In tidal reaches, all six rivers flow over alluvial deposits, but have varying gradients (0.0001-0.0013 m/m) and lengths affected by tide (1.3-24.6 km). The Miami River has the steepest and shortest tidal reach and the Nehalem River has the flattest and longest tidal reach. Bars in the tidal reaches are generally composed of sand and mud. Unit bar area was greatest in the Tidal Nehalem Reach, where extensive mud flats flank the lower channel. * Background factors such as valley and channel confinement, basin geology, channel slope, and tidal extent control the spatial variation in the accumulation and texture of bed material. Presently, the Upper Fluvial Wilson and Miami Reaches and Fluvial Nehalem Reach have the greatest abundance of gravel bars, likely owing to local bed-material sources in combination with decreasing channel gradient and valley confinement. * Natural and human-caused disturbances such as mass movements, logging, fire, channel modifications for navigation and flood control, and gravel mining also have varying effects on channel condition, bed-material transport, and distribution and area of bars throughout the study areas and over time. * Existing datasets include at least 16 and 18 sets of aerial and orthophotographs that were taken of the study areas in the Tillamook Bay tributary basins and Nehalem River basin, respectively, from 1939 to 2011. These photographs are available for future assessments of long-term changes in channel condition, bar area, and vegetation establishment patterns. High resolution Light Detection And Ranging (LiDAR) surveys acquired in 2007-2009 could support future quantitative analyses of channel morphology and bed-material transport in all study areas. * A review of deposited and mined gravel volumes reported for instream gravel mining sites shows that bed-material deposition tends to rebuild mined bar surfaces in most years. Mean annual deposition volumes on individual bars exceeded 3,000 cubic meters (m3) on Donaldson Bar on the Wilson River, Dill Bar on the Kilchis River, and Plant and Winslow Bars on the Nehalem River. Cumulative reported volumes of bed-material deposition were greatest at Donaldson and Dill Bars, totaling over 25,000 m3 per site from 2004 to 2011. Within this period, reported cumulative mined volumes were greatest for the Donaldson, Plant, and Winslow Bars, ranging from 24,470 to 33,940 m3. * Analysis of historical stage-streamflow data collected by the U.S. Geological Survey on the Wilson River near Tillamook (14301500) and Nehalem River near Foss (14301000) shows that these rivers have episodically aggraded and incised, mostly following high flow events, but they do not exhibit systematic, long-term trends in bed elevation. * Multiple cross sections show that channels near bridge crossings in all six study areas are dynamic with many subject to incision and aggradation as well as lateral shifts in thalweg position and bank deposit

Jones, Krista L.; Keith, Mackenzie K.; O'Connor, Jim E.; Mangano, Joseph F.; Wallick, J. Rose

2012-01-01

178

Runoff processes, stream water residence times and controlling landscape characteristics in a mesoscale catchment: An initial evaluation  

NASA Astrophysics Data System (ADS)

Tracer studies, using Gran alkalinity and ?18O, in nested sub-basins of the 230 km 2 Feshie catchment in the Cairngorm mountains, Scotland, were used to characterise hydrology in terms of groundwater contributions to annual runoff and mean residence times. Relationships between these fundamental hydrological descriptors and catchment characteristics were explored with the use of a GIS. Catchment soil distribution—mapped by the UK's Hydrology Of Soil Type (HOST) digital data base—exerted the strongest influence on flow path partitioning and mean residence times. Smallest groundwater contributions (˜30-40%) and shortest residence times (˜2-5 months) were observed in catchments dominated by peat and/or shallow alpine soils and bedrock. Longer residence times (˜12-15 months) and greater groundwater contributions (˜45-55%) were observed in catchments dominated by more freely draining podzolic, sub-alpine and alluvial soils. These different subcatchment responses were integrated to give intermediate residence times (˜6 months) at the catchment outfall. The influence of catchment topography and scale appeared to be largely mediated by their influence on soil cover and distribution. The study illustrates the potential utility of integrating digital landscape analysis with tracer studies to understand the hydrological functioning of mesoscale catchments.

Soulsby, C.; Tetzlaff, D.; Rodgers, P.; Dunn, S.; Waldron, S.

2006-06-01

179

Geological controls on isotopic signatures of streamflow: results from a nested catchment experiment in Luxembourg (Europe)  

NASA Astrophysics Data System (ADS)

Controls of geology and topography on hydrological metrics, like summer low flow (Grant and Tague, 2004) or dynamic storage (Sayama et al., 2011), have been identified in nested catchment experiments. However, most tracer-based studies on streamflow generation have been carried out in small (10 km2) homogenous catchments (Klaus and McDonnell, 2013). The controlling effects of catchment physiography on how catchments store and release water, and how this eventually controls stream isotope behaviour over a large range of scale are poorly understood. Here, we present results from a nested catchment analysis in the Alzette River basin (Luxembourg, Europe). Our hydro-climatological network consists of 16 recording streamgauges and 21 pluviographs. Catchment areas range from 0.47 to 285 km2, with clean and mixed combinations of distinct geologies ranging from schists to marls, sandstone, dolomite and limestone. Our objective was to identify geological controls on (i) winter runoff ratios, (ii) maximum storage and (iii) isotopic signatures in streamflow. For each catchment we determined average runoff ratios from winter season precipitation-discharge double-mass curves. Maximum catchment storage was based on the dynamic storage change approach of Sayama et al. (2011). Changes in isotopic signatures of streamflow were documented along individual catchment flow duration curves. We found strong correlations between average winter runoff ratios, maximum storage and the prevailing geological settings. Catchments with impermeable bedrock (e.g. marls or schists) were characterised by small storage potential and high average filling ratios. As a consequence, these catchments also exhibited the highest average runoff ratios. In catchments underlain by permeable bedrock (e.g. sandstone), storage potential was significantly higher and runoff ratios were considerably smaller. The isotopic signatures of streamflow showed large differences between catchments. In catchments dominated by permeable bedrock, isotopic signatures of streamflow remained stable throughout the entire flow duration curve consistent with a large storage and mixing potential. On less permeable bedrock substrate, we have observed that isotopic signatures in streamflow were much more variable, due to reduced storage volume and comparatively smaller mixing potential. Other metrics such as catchment size and flowpath length exerted a smaller secondary control on isotopic signatures of streamflow in the Alzette River sub-basins. Tague, C., Grant, G.E., 2004. A geological framework for interpreting the low-flow regimes of Cascade streams, Willamette River Basin, Oregon. Water Resources Research, 40(4), doi:10.1029/2003WR002629 Sayama, T., McDonnell, J.J., Dhakal, A., Sullivan, K., 2011. How much water can a watershed store ? Hydrological Processes 25, 3899-3908. Klaus, J., McDonnell, J.J., 2013. Hydrograph separation using stable isotopes: Review and evaluation. Journal of Hydrology 505, 47-64.

Pfister, Laurent; McDonnell, Jeffrey J.; Hissler, Christophe; Martinez-Carreras, Nuria; Gourdol, Laurent; Klaus, Julian; François Iffly, Jean; Barnich, François; Stewart, Mike K.

2014-05-01

180

Applying different spatial distribution and modelling concepts in three nested mesoscale catchments of Germany  

NASA Astrophysics Data System (ADS)

Distributed, physically based river basin models are receiving increasing importance in integrated water resources management (IWRM) in Germany and in Europe, especially after the release of the new European Water Framework Directive (WFD). Applications in mesoscale catchments require an appropriate approach to represent the spatial distribution of related catchment properties such as land use, soil physics and topography by utilizing techniques of remote sensing and GIS analyses. The challenge is to delineate scale independent homogeneous modelling entities which, on the one hand may represent the dynamics of the dominant hydrological processes and, on the other hand can be derived from spatially distributed physiographical catchment properties. This scaling problem is tackled in this regional modelling study by applying the concept of hydrological response units (HRUs). In a nested catchment approach three different modelling conceptualisations are used to describe the runoff processes: (i) the topographic stream-segment-based HRU delineation proposed by Leavesley et al. [Precipitation-Runoff-Modelling-System, User’s Manual, Water Resource Investigations Report 83-4238, US Geological Survey, 1983]; (ii) the process based physiographic HRU-concept introduced by Flügel [Hydrol. Process. 9 (1995) 423] and (iii) an advanced HRU-concept adapted from (ii), which included the topographic topology of HRU-areas and the river network developed by Staudenraush [Eco Regio 8 (2000) 121]. The influence of different boundary conditions associated with changing the landuse classes, the temporal data resolution and the landuse scenarios were investigated. The mesoscale catchment of the river Ilm ( A?895 km 2) in Thuringia, Germany, and the Precipitation-Runoff-Modelling-System (PRMS) were selected for this study. Simulations show that the physiographic based concept is a reliable method for modelling basin dynamics in catchments up to 200 km 2 whereas in larger catchments, where lateral processes dominate, the other concepts have advantages.

Bongartz, K.

181

Hydrological Response of Semi-arid Degraded Catchments in Tigray, Northern Ethiopia  

NASA Astrophysics Data System (ADS)

To address water scarcity in the arid and semi-arid part of developing countries, accurate estimation of surface runoff is an essential task. In semi-arid catchments runoff data are scarce and therefore runoff estimation using hydrological models becomes an alternative. This research was initiated in order to characterize runoff response of semi-arid catchments in Tigray, North Ethiopia to evaluate SCS-CN for various catchments. Ten sub-catchments were selected in different river basins and rainfall and runoff were measured with automatic hydro-monitoring equipments for 2-3 years. The Curve Number was estimated for each Hydrological Response Unit (HRU) in the sub-catchments and runoff was modeled using the SCS-CN method at ? = 0.05 and ? = 0.20. The result showed a significant difference between the two abstraction ratios (P =0.05, df = 1, n= 132) and reasonable good result was obtained for predicted runoff at ? = 0.05 (NSE = -0.69; PBIAS = 18.1%). When using the CN values from literature runoff was overestimated compared to the measured value (e= -11.53). This research showed the importance of using measured runoff data to characterize semi-arid catchments and accurately estimate the scarce water resource. Key words: Hydrological response, rainfall-runoff, degraded environments, semi-arid, Ethiopia, Tigray

Teka, Daniel; Van Wesemael, Bas; Vanacker, Veerle; Hallet, Vincent

2013-04-01

182

Assessment of interbasin groundwater flows between catchments using a semi-distributed water balance model  

NASA Astrophysics Data System (ADS)

In hydrological modeling it is often assumed that the aquifers boundaries are formed by the geographical demarcation of the catchment. However, this assumption is rarely met, given the existence of groundwater flows going beyond the catchment limits. The assessment of interbasin groundwater flows is crucial when managing water resources in areas where baseflows are mainly formed by groundwater, especially when catchments are managed separately. Aiming at estimating the volume and direction of the main groundwater flows, this work presents a new methodological approach for hydrological modeling. This approach employs a semi-distributed water balance model created with lumped models. This model is formulated in such a way that a part of the groundwater discharge of a specific catchment can become baseflows in other catchments, which helps characterize interbasin groundwater flows. This methodology is applied in the headwater of the Segura River Basin (southeast of Spain), where groundwater plays an important role in surface hydrology. The catchments are modeled with a high goodness of fit, and the main interbasin groundwater flows between them is evaluated, proving its importance in the characterization of hydrological modeling.

Pellicer-Martínez, Francisco; Martínez-Paz, José Miguel

2014-11-01

183

A Basin Morphology Approach to Colour Image Segmentation by Region Merging  

E-print Network

A Basin Morphology Approach to Colour Image Segmentation by Region Merging Erchan Aptoula and S by region merging, with the procedure being formalized as a basin morphology, where regions are "eroded" in order to form greater catchment basins. The result is a fully automated processing chain, with multiple

Lefèvre, Sébastien

184

Quantifying Spatial Variability in Runoff Quality in Semi-arid Urban Catchments  

NASA Astrophysics Data System (ADS)

Urbanization alters ecosystem function and subsequently impacts quantity and quality of stormwater runoff. In arid and semi-arid urban ecosystems, solutes may accumulate in upland environments for several months between rainfall events, which flush these potential pollutants to stream channels. Although this decline in water quality is well documented with urbanization, it is unclear how different urbanization intensities affect catchment hydrologic responses and N dynamics in semi-arid regions. We expected that N would decline with increasing impervious cover. In heavily urbanized watersheds, N delivery would be controlled primarily by hydrologic transport and would exhibit a conservative flushing response. In watersheds with a lower density of development, N delivery would be related to complex source-sink relationships and would not exhibit a conservative flushing response. To address these hypotheses, we collected rainfall and stormwater runoff samples from 22 catchments in Tucson AZ that vary in percent impervious cover (IC, 2.92% to 90.7%) and catchment area (0.33km2 to 28.48km2.) We used a combination of 22 single-stage siphon samplers; one per catchment, paired with six multiple-stage automatic water collectors in a subset of catchments, to efficiently and inexpensively collect runoff samples across a wide these gradients of urbanization. There is a strong (r2 = 0.79) and significant (p < 0.05) correlation between the auto sampler and siphon sampler runoff quality. We found that pH and EC do not vary with catchment area, suggesting that the entire catchment may not be contributing surface runoff and solutes to streamflow. However, EC significantly increases with IC, while pH significantly decreases with IC. Data suggest that at high IC, pH of runoff begins to approximate the pH of rainfall (6.75). Given that urban catchments are designed to efficiently route runoff into waterways, it is plausible the increased IC results in more efficient mobilization of solutes, in a shorter time range, which may explain why pH begins to approximate rainfall at higher IC. We observe a significant decrease in EC over the monsoon (July to Sept) while at the same time observing a significant increase in pH, which may be the result of seasonal solute flushing. Preliminary data show that NH4-N does not vary with IC and catchment area, while PO4-P appears to decrease with catchment size and increase with IC, suggesting that some runoff solutes more directly impacted by land cover and biogeochemical catchment processes. Findings from our study suggest that imperviousness and seasonal dynamics impart a greater control on runoff quality than catchment size.

Peterson, A. M.; Gallo, E. L.; Lohse, K. A.; Brooks, P. D.; Meixner, T.

2010-12-01

185

Sediment sources and its transport pathways in the Kharaa catchment, northern Mongolia  

NASA Astrophysics Data System (ADS)

Soil erosion and its subsequent transport towards and within rivers is complex, dependent on many catchment properties, hydrology and land use. However, little is known about the sources and fate of suspended sediment (SS) in the 15.000km2 Kharaa study catchment in Mongolia. This study focuses therefore on a qualitative identification of sediment sources and the quantification of the suspended sediment transport in the catchment. Geochemical sediment source fingerprinting in combination with isotope fingerprinting is used to identify and localize the most important sediment source areas in the catchment and assess their contribution to the suspended sediment load. More than 1000 grab samples from 22 river junctions of the outlet of each sub basin into the main tributary were taken in the period from 2009 to 2011. Their fine sediment fractions (<10?m) have been analysed for major elements (e.g. Si, Al, Mg) and trace elements (e.g. Ba, Pb, Sr,) using ICP-MS. The contribution of each sub basin to the SS in the main tributary has then been calculated using mixing model analysis. Additionally, isotope fingerprinting was used to assess the importance and contribution of surface, stream bank and gully erosion on total sediment load of the catchment. Biannual samples of 12 topsoil eroding surface reference sites, 4 stream banks and 4 suspended sediment samples were analysed for the atmospheric fallout radionuclides Cs-137, Pb-210 and Be-7 using gamma ray spectrometry. The sediment budget of the catchment was calculated with the help of the regional catchment scale sediment budget model (SedNet. Results suggest that only a small part of the catchment contributes considerably to the total sediment load and that gully and bank erosion might be the dominating sources in the catchment that lead to fine sediment intrusion and ecosystem degradation in the riverbed in the midstream regions. Also there seems to be a difference in erosion behaviour between spring and fall, with a higher contribution from surface erosion during summer rainfall. Future work will concentrate on scenario analysis modelling of the sediment transport in the catchment with HYPE as well as uncertainty analysis of the model.

Theuring, P.; Rode, M.

2012-04-01

186

Hydrological response of a Mediterranean agricultural catchment on a Vertic soil  

NASA Astrophysics Data System (ADS)

Hydrological response of vertic soils is strongly controlled by the modification of its hydraulic conditions by the shrinking and swelling cycles, which are controlled by the climatology of the year. This presents additional challenges to the already difficult task of hydrologic and erosion modelling at hillslope and catchment scale (Allen et al., 2005). However, there is limited experimental information on the hydrologic response of vertic soils at catchment scale. This communications presents a preliminary evaluation of the hydrologic impact of an small, 8 ha, catchment in Southern Spain covered by olive groves on a vertic soil. This evaluation is made on the runoff and rainfall records measured at catchment scale from September 2006 to August 2011, and at runoff plot scale from September 2000 to August 2004 and September 2009 to August 2011. These results are analyzed following the same statistical analysis described by Taguas et al. (2009) enlarging this analysis with an evaluation of the correlation between the hydrologic response of the catchment, with the evolution of the soil water content in the orchard simulated using a conceptual soil water balance model, WABOL (Abazi et al., 2012) The results of the analysis will be discussed in relation to the variability of the hydrologic response at different time and spatial scales (catchment and hillslope) and its implications for modelling and extrapolation to similar soils under different climate and crop conditions.

Gomez, J. A.; Taguas, E.; Licciardello, F.

2012-04-01

187

Preliminary results on the characterization of Cretaceous and lower Tertiary low-permeability (tight) gas-bearing rocks in the Wind River Basin, Wyoming  

SciTech Connect

The Wind River Basin is a structural and sedimentary basin in central Wyoming (Figure 1) that was created during the Laramide orogeny from Late Cretaceous through Eocene time. The objectives of the Wind River Basin tight gas sandstone project are to define the limits of the tight gas accumulation in the basin and to estimate in-place and recoverable gas resources. The approximate limits of the tight gas accumulation are defined from available drillhole information. Geologic parameters, which controlled the development of the accumulation, are studied in order to better understand the origins of tight gas accumulations, and to predict the limits of the accumulation in areas where little drillhole information is available. The architecture of sandstone reservoirs are studied in outcrop to predict production characteristics of similar reservoirs within the tight gas accumulation. Core and cuttings are used to determine thermal maturities, quality of source rocks, and diagenetic histories. Our work thus far has concentrated in the Wind River Indian Reservation in the western part of the basin.

Fouch, T.D.; Keefer, W.R.; Finn, T.M. [and others

1993-12-31

188

Factors controlling mercury transport in an upland forested catchment  

USGS Publications Warehouse

Total mercury (Hg) deposition and input/output relationships were investigated in an 11-ha deciduous forested catchment in northern Vermont as part of ongoing evaluations of rig cycling and transport in the Lake Champlain basin. Atmospheric Hg deposition (precipitation + modeled vapor phase downward flux) was 425 mg ha-1 during the one-year period March 1994 through February 1995 and 463 mg ha-1 from March 1995 through February 1996. In the same periods, stream export of total Hg was 32 mg ha-1 and 22 mg ha-1, respectively. Thus, there was a net retention of Hg by the catchment of 92% the first year and 95% the second year. In the first year, 16.9 mg ha-1 or about half of the annual stream export, occurred on the single day of peak spring snowmelt in April. In contrast, the maximum daily export in the second year, when peak stream flow was somewhat lower, was 3.5 mg ha-1 during a January thaw. The fate of file Hg retained by this forested catchment is not known. Dissolved (< 0.22 ??m) Hg concentrations in stream water ranged from 0.5-2.6 ng L-1, even when total (unfiltered) concentrations were greater than 10 ng L-1 during high flow events. Total Hg concentrations in stream water were correlated with the total organic fraction of suspended sediment, suggesting the importance of organic material in Hg transport within the catchment. High flow events and transport with organic material may be especially important mechanisms for the movement of Hg through forested ecosystems.

Scherbatskoy, T.; Shanley, J.B.; Keeler, G.J.

1998-01-01

189

Hydrological response of climate change in a glaciated catchment in the Himalayas  

NASA Astrophysics Data System (ADS)

Hydrological effects of climate change on glaciated catchments are difficult to assess due to a poor representation of future glacial evolution in most models and the large heterogeneity of climate in areas with steep topography. We develop a spatial-dynamic hydrological model of the Langtang catchment (Nepal) at a spatial resolution of 90 meter that relates river runoff to precipitation and glacial melt processes. The model is forced by high resolution temperature and precipitation fields and at each daily time step precipitation is partitioned in either snow or rain. Part of the rain is routed along the digital elevation model (DEM) and leaves the catchment as rain runoff, while snow accumulates in the upstream parts of the basin and feeds the glaciers. Whereas previous hydrological studies adopt a simple degree day approach in combination with lumped glacier areas to quantify glacial melt, in this study the dynamic sliding of glaciers in the downstream direction is explicitly modeled. Glacier sliding is based on the shear stress with the bedrock and is evaluated on a pixel basis according to Weertman’s sliding law. Glaciers only slide when the shear stress exceeds a threshold value that is derived using the slope of the terrain, local glacier thickness and assuming perfect plasticity of the ice. Each time step the sliding ice is transported down the digital elevation model and as temperature increases a degree day factor method is used to model ablation. The melt water is subsequently routed along the DEM. A two step calibration approach was used. Firstly, a 40 year period from 1960-2000 was simulated to calibrate the threshold shear stress, the degree day factor and the resistance of the bedrock using the observed glacier extent in 2000. Secondly, the rain runoff coefficient and base flow parameters were calibrated using observed daily discharges at the outlet of the catchment from 2000 to 2007. Results show that model is able to accurately simulate both the glacier extent using the 40 year time series and the discharge from 2000 to 2007. Based on precipitation and temperature change fields of the IPCC AR4 A1B scenario the effects of climate change on the hydrology are simulated for a time slice around 2050 and 2090. Preliminary results show that the glaciers withdraw significantly in the future, but that the reduction in melt water is compensated for by an increase in rain runoff. Given the fact that monsoon season coincides with the melt season no significant temporal shifts in the hydrograph occur and effects for downstream areas are likely to be limited. The innovative approach used to model the glaciers is highly suitable for climate change studies as it allows quantifying the future evolution of the glacier tongues dynamically without making assumptions on future glacier extent

Immerzeel, W. W.; Bierkens, M. F.; van Beek, L. P.

2009-12-01

190

Bayesian Uncertainty of Thwaites Glacier Catchment Radar Stratigraphy  

NASA Astrophysics Data System (ADS)

Information about the history and dynamics of ice sheets is contained in basin-scale radar sounding surveys. Englacial, isochronous radar horizons traced throughout the sampled domain of these basins can give a three-dimensional picture of past ice flow by revealing significant details of deformation within the ice column. We focus our efforts in the Thwaites Glacier catchment, West Antarctica, which previous studies have shown to be a bellwether in future WAIS deglaciation scenarios. Here we present a Bayesian determination of the age-depth profile at the Byrd ice core, Antarctica, based on robust uncertainty estimates in ice core ages and radar sounding depths. A simple ice flow model is used to determine the age-depth relationship in ice near the core and a Markov Chain Monte Carlo technique is used to sample a posterior distribution of age as a function of depth to within uncertainty. We propagate the age-depth information, including uncertainty, for several prominent radar reflectors from the Byrd ice-coring site in the Interior Ross Embayment across the ice divide and throughout the Thwaites Glacier catchment using airborne ice-penetrating radar data collected and processed by the University of Texas Institute for Geophysics.

Gutowski, G.; Jackson, C. S.; Blankenship, D. D.; Young, D. A.; Cavitte, M. G.

2013-12-01

191

Fate of organic contaminants in a boreal forest catchment  

NASA Astrophysics Data System (ADS)

The aim of the study was to investigate and predict the impact of hydrological and atmospheric processes on the mobilisation of contaminants in a remote catchment where the major input is related to diffuse pollution. The project included priory substances according to the European water framework directive (WFD), such as the persistent organic pollutants (POPs) HCB, PCBs and dioxins. The study was conducted at a well-characterised catchment system in northern Sweden dominated by two landscape types: forest and mire. Chemical analyses of POPs in forest soil and mire peat at various depths were performed. Evaluation of POP composition by principal component analysis (PCA) showed distinct differences between surface and deeper samples. This was attributed to vertical transport, degradation and/or shifting sources over time. The calculated net vertical transport differed between surface (0.3% of the pollutant reservoir) and deeper soils (8.0 %), suggesting that vertical transport conditions and processes differ in the deeper layers compared to the surface layers.The fate of POPs in soils and waters was explored through the development of a chemical fate model. The northerly location of the studied catchment enabled a study on the impact of spring snow melt and associated hydrological processes on contaminant mobilization. Input was based on bulk atmospheric deposition and was dominated by accumulation in the winter snowpack. The model considered air-soil exchange and accumulation in forest and mire soil as well as export of dissolved and particle-bound POPs from soil to catchment surface water. The predicted export of POPs to catchment surface waters was up to 40 times higher the during snow melt period (three week during April/May) compared to the snow covered period (approximately 4 months), highlighting the importance of the seasonal snow pack as a source of these chemicals. Release from soils was governed by the POP concentration in soil, the fraction of soil organic carbon and soil-water dissolved organic carbon (DOC) content. Significant differences in export of POPs were apparent between the forested and mire areas, and this could be linked to observed differences in hydrology, biogeochemistry and flux of DOC. Levels of POPs in surface water along the water path from the studied catchment to the Baltic Sea (the Gulf of Bothnia subbasin) were measured and the results showed that for this water system, atmospherically derived diffuse pollution has impact on the surface water quality in addition to downstream point sources. In conclusion, it is evident that a full understanding of the baseline contribution and the soil-to-water processes controlling the transport of priority substances at catchment scale is a prerequisite for assessing the variation of priority substances in water streams and river basins on a seasonal and regional scale. It is also clear that mobilization of headwater atmospherically derived diffuse pollution may have an impact on stream water quality in addition to downstream point sources. The above findings are applicable to a wide variety of north European catchments systems and provide an integrated and process-based understanding of base-line contamination of major catchments. The presented data highlight the findings from the PERSPEC project, which was possible under the umbrella of the European Commission's 6th Framework Programme project SNOWMAN (contract no ERAC-CT-2003-003219).

Bergknut, Magnus; Meijer, Sandra; Halsall, Crispin; Ågren, Anneli; Laudon, Hjalmar; Köhler, Stephan; Jones, Kevin; Tysklind, Mats; Wiberg, Karin

2010-05-01

192

Dissolved Organic Carbon dynamics in a Mediterranean mountain catchment  

NASA Astrophysics Data System (ADS)

The dynamics of water solutes in Mediterranean mountain areas is complex and difficult to predict as Mediterranean regions are characterized by a strong intra- and inter-annual precipitation variability and a strong climatic seasonality that lead to a very contrasted hydrological response along the year. Nonetheless, an improved understanding of the catchment hydrological functioning can be obtained from the analysis of solute dynamics in rainfall, stream water, soil water and groundwater. Dissolved organic carbon (DOC) dynamics at the catchment scale has been studied in many environments, but there are relatively few studies in Mediterranean mountain regions. With the objective of improving the knowledge of DOC dynamics in seasonal Mediterranean environments, rainfall, soil water, groundwater and stream water samples were taken on a regular basis, as well as during rainfall-runoff events along a 26 month period in the Can Vila research catchment (NE Spain, 42º 12'N, 1º 49'E). Detailed distributed hydrometric measurements (precipitation, discharge, soil moisture and water table level) were obtained during the same period. Using these data we characterized the DOC dynamics in the different hydrological compartments and analyzed the factors which affect them. We also analyzed the DOC dynamics during rainfall-runoff events to assess possible differences in the hydrological functioning of the catchment between dry and wet conditions. Preliminary results suggest that at seasonal scale DOC dynamics of stream water and groundwater are affected by discharge and water table dynamics, respectively, as DOC dynamics follow the hydrological trends. During rainfall-runoff events, an increase of DOC concentration was observed in the stream. However the DOC dynamics during floods showed some differences between events suggesting some changes in the dominant runoff processes.

Roig-Planasdemunt, Maria; Llorens, Pilar; Latron, Jérôme

2014-05-01

193

A physically-based Distributed Hydrologic Model for Tropical Catchments  

NASA Astrophysics Data System (ADS)

Hydrological models are mathematical formulations intended to represent observed hydrological processes in a watershed. Simulated watersheds in turn vary in their nature based on their geographic location, altitude, climatic variables and geology and soil formation. Due to these variations, available hydrologic models vary in process formulation, spatial and temporal resolution and data demand. Many tropical watersheds are characterized by extensive and persistent biological activity and a large amount of rain. The Agua Salud catchments located within the Panama Canal Watershed, Panama, are such catchments identified by steep rolling topography, deep soils derived from weathered bedrock, and limited exposed bedrock. Tropical soils are highly affected by soil cracks, decayed tree roots and earthworm burrows forming a network of preferential flow paths that drain to a perched water table, which forms at a depth where the vertical hydraulic conductivity is significantly reduced near the bottom of the bioturbation layer. We have developed a physics-based, spatially distributed, multi-layered hydrologic model to simulate the dominant processes in these tropical watersheds. The model incorporates the major flow processes including overland flow, channel flow, matrix and non-Richards film flow infiltration, lateral downslope saturated matrix and non-Darcian pipe flow in the bioturbation layer, and deep saturated groundwater flow. Emphasis is given to the modeling of subsurface unsaturated zone soil moisture dynamics and the saturated preferential lateral flow from the network of macrospores. Preliminary results indicate that the model has the capability to simulate the complex hydrological processes in the catchment and will be a useful tool in the ongoing comprehensive ecohydrological studies in tropical catchments, and help improve our understanding of the hydrological effects of deforestation and aforestation.

Abebe, N. A.; Ogden, F. L.

2010-12-01

194

Analyzing runoff processes through conceptual hydrological modelling in the Upper Blue Nile basin, Ethiopia  

NASA Astrophysics Data System (ADS)

Understanding runoff processes in a basin is of paramount importance for the effective planning and management of water resources, in particular in data scarce regions of the Upper Blue Nile. Hydrological models representing the underlying hydrological processes can predict river discharges from ungauged catchments and allow for an understanding of the rainfall-runoff processes in those catchments. In this paper, such a conceptual process-based hydrological model is developed and applied to the upper Gumara and Gilgel Abay catchments (both located within the Upper Blue Nile basin, the Lake Tana sub-basin) to study the runoff mechanisms and rainfall-runoff processes in the basin. Topography is considered as a proxy for the variability of most of the catchment characteristics. We divided the catchments into different runoff production areas using topographic criteria. Impermeable surfaces (rock outcrops and hard soil pans, common in the Upper Blue Nile basin) were considered separately in the conceptual model. Based on model results, it can be inferred that about 65% of the runoff appears in the form of interflow in the Gumara study catchment, and baseflow constitutes the larger proportion of runoff (44-48%) in the Gilgel Abay catchment. Direct runoff represents a smaller fraction of the runoff in both catchments (18-19% for the Gumara, and 20% for the Gilgel Abay) and most of this direct runoff is generated through infiltration excess runoff mechanism from the impermeable rocks or hard soil pans. The study reveals that the hillslopes are recharge areas (sources of interflow and deep percolation) and direct runoff as saturated excess flow prevails from the flat slope areas. Overall, the model study suggests that identifying the catchments into different runoff production areas based on topography and including the impermeable rocky areas separately in the modeling process mimics well the rainfall-runoff process in the Upper Blue Nile basin and brings a useful result for operational management of water resources in this data scarce region.

Dessie, M.; Verhoest, N. E. C.; Pauwels, V. R. N.; Admasu, T.; Poesen, J.; Adgo, E.; Deckers, J.; Nyssen, J.

2014-05-01

195

Mass balance of major solutes in a rainforest catchment in the Central Amazon: Implications for nutrient budgets in tropical rainforests  

Microsoft Academic Search

A solute mass balance for a 23.4 ha catchment of undisturbed rainforest in the central Amazon Basin was computed from detailed measurements of water and solute fluxes via rainfall, streamflow, and subsurface outflow over an annual cycle. Annual atmospheric deposition fluxes are lower than previously reported among mass balance studies conducted in the Amazon. Nutrient export fluxes are lower than

Lance F. W. Lesack; John M. Melack

1996-01-01

196

Nutrient sources in a Mediterranean catchment and their improvement for water quality management  

NASA Astrophysics Data System (ADS)

Changes in land-use or management strategies may affect water outflow, sediment and nutrients loads. Thus, there is an increasing demand for quantitative information at the catchment scale that would help decision makers or planners to take appropriate decisions. The characterisation of water status, the description of pollution sources impact, the establishment of monitoring programs and the implementation of river basin management plans require an analysis of the current basin status and estimates of the relative significance of the different sources of pollution. Particularly, in this study the Soil and Water Assessment Tool (SWAT2000) model was considered since it is an integrated hydrological model that simulates both the qualitative as well as quantitative terms of hydrological balances. It is a spatially distributed hydrological model that operates on a daily time step at catchment scale developed by the Agricultural Research Service at the U.S. Department of Agriculture. Its purpose is to simulate water sediment and chemical yields on large river basins and possible impacts of land use, climate changes and watershed management. Integrated hydrological models are, nowadays, needed to support the implementation of integrated water management plans and to comply with the current requirements of the European Water Directive. Actually, they can help in evaluating current water resources, identify pollution sources, evaluate alternative management policies. More specifically, the analysis has been applied to the Oreto catchment (77 Km2), an agricultural and urbanised catchment located in Sicily (Italy). Residential, commercial, farm and industrial settlements cover almost the entire area. The climate is Mediterranean with hot dry summer and rainy winter season. The hydrological response of this basin is dominated by long dry seasons and following wetting-up periods, during which even large inputs of rainfall may produce little or no response at the basin outlet. Regarding the inventory of point and non-point pollutants sources, the river receives a number of point source pollutants from small villages and some outskirts of Palermo, most of them untreated, and non point source pollutants from agricultural cropland and zoo-technical farms. In particular, the Oreto river receives untreated wastewater and stormwater from Altofonte (8200 inhabitants) and Pioppo (2500 inhabitants) . The model was first calibrated using meteorological, flow and water quality data collected at various stations through-out the catchment, in order to predict water and nutrient concentrations at the catchment outlet and then was used to evaluate the potential impact of various management strategies on surface water quality. The results demonstrates that point and non-point polluting sources have to be contiguously analysed because they concur to the definition of river water quality both during wet and dry periods.

Candela, Angela; Viviani, Gaspare

2010-05-01

197

Hydrothermal deposits in the Southern Trough of Guaymas Basin, Gulf of California: Observations and Preliminary Results from the 2003 MBARI Dive Program  

Microsoft Academic Search

During Leg 2 of the 2003 MBARI expedition to the Gulf of California, the ROV Tiburon completed eight dives to active vent fields in the Southern Trough of Guaymas Basin. Six venting areas were investigated in detail. Tiburon operations included (1) sampling mineral deposits that range from mini-chimneys a few centimeters high to 10-meter-tall sulfide-carbonate structures with wide flanges; (2)

D. S. Stakes; M. K. Tivey; R. A. Koski; A. Ortego-Osorio; C. M. Preston; M. T. McCulloch; K. Nakamura; J. Seewald; C. G. Wheat

2003-01-01

198

Sediment yield estimation in mountain catchments of the Camastra reservoir, southern Italy: a comparison among different empirical methods  

NASA Astrophysics Data System (ADS)

Sedimentary budget estimation is an important topic for both scientific and social community, because it is crucial to understand both dynamics of orogenic belts and many practical problems, such as soil conservation and sediment accumulation in reservoir. Estimations of sediment yield or denudation rates in southern-central Italy are generally obtained by simple empirical relationships based on statistical regression between geomorphic parameters of the drainage network and the measured suspended sediment yield at the outlet of several drainage basins or through the use of models based on sediment delivery ratio or on soil loss equations. In this work, we perform a study of catchment dynamics and an estimation of sedimentary yield for several mountain catchments of the central-western sector of the Basilicata region, southern Italy. Sediment yield estimation has been obtained through both an indirect estimation of suspended sediment yield based on the Tu index (mean annual suspension sediment yield, Ciccacci et al., 1980) and the application of the Rusle (Renard et al., 1997) and the USPED (Mitasova et al., 1996) empirical methods. The preliminary results indicate a reliable difference between the RUSLE and USPED methods and the estimation based on the Tu index; a critical data analysis of results has been carried out considering also the present-day spatial distribution of erosion, transport and depositional processes in relation to the maps obtained from the application of those different empirical methods. The studied catchments drain an artificial reservoir (i.e. the Camastra dam), where a detailed evaluation of the amount of historical sediment storage has been collected. Sediment yield estimation obtained by means of the empirical methods have been compared and checked with historical data of sediment accumulation measured in the artificial reservoir of the Camastra dam. The validation of such estimations of sediment yield at the scale of large catchments using sediment storage in reservoirs provides a good opportunity: i) to test the reliability of the empirical methods used to estimate the sediment yield; ii) to investigate the catchment dynamics and its spatial and temporal evolution in terms of erosion, transport and deposition. References Ciccacci S., Fredi F., Lupia Palmieri E., Pugliese F., 1980. Contributo dell'analisi geomorfica quantitativa alla valutazione dell'entita dell'erosione nei bacini fluviali. Bollettino della Società Geologica Italiana 99: 455-516. Mitasova H, Hofierka J, Zlocha M, Iverson LR. 1996. Modeling topographic potential for erosion and deposition using GIS. International Journal of Geographical Information Systems 10: 629-641. Renard K.G., Foster G.R., Weesies G.A., McCool D.K., Yoder D.C., 1997. Predicting soil erosion by water: a guide to conservation planning with the Revised Universal Soil Loss Equation (RUSLE), USDA-ARS, Agricultural Handbook No. 703.

Lazzari, Maurizio; Danese, Maria; Gioia, Dario; Piccarreta, Marco

2013-04-01

199

Influence of geology, regolith and soil on fluid flow pathways in an upland catchment in central NSW, Australia  

NASA Astrophysics Data System (ADS)

Influence of geology, regolith and soil on fluid flow pathways in an upland catchment in central NSW, Australia. Tony Bernardi and Leah Moore Dryland Salinity Hazard Mitigation Program (DSHMP), University of Canberra, ACT 2601, AUSTRALIA The diversity of salt expression in central NSW has defied classification because salt expression, mobilisation and transport is highly variable and is typically site specific. Hydrological models are extensively used to simulate possible outcomes for a range of land use changes to mitigate the mobilisation and transport of salt into the streams or across the land surface. The ability of these models to mimic reality can be variable thereby reducing the confidence in the models outputs and uptake of strategic management changes by the community. This study focuses on a 250 ha semi-arid sub-catchment of Little River catchment in central west NSW in the Murray-Darling Basin, Australia. We propose that an understanding the structure of the landforms and configuration of rock, regolith and soil materials at the study site influences fluid flow pathways in the landscape and can be related to observed variations in the chemical composition and salinity of surface and aquifer water. Preliminary geological mapping of the site identified the dominant rock type as a pink and grey dacite and in localised mid-slope areas, a coarsely crystalline biotite-phyric granodiorite. Samples were taken at regular intervals from natural exposures in eroded stream banks and in excavations made during the installation of neutron moisture meter tubes. In order to establish mineral weathering pathways, samples were taken from the relatively unweathered core to the outer weathered 'onion skins' of corestones on both substrates, and then up through the regolith profile, including the soil zone, to the land surface. X-ray diffraction (XRD) analysis and X-ray fluorescence (XRF) was conducted on the rock and soil/saprock samples. Electromagnetic induction (EMI) profile data were compiled from previous work with colleagues in this area. Preliminary interpretation of the mapping and the geophysics is that there is a three-layer framework for groundwater modelling: fractured granitic rock with an irregular upper surface, finer-grained (volcanic) rock that has either mantled the older granite or has been intruded into, and a weathering profile developed in relation to the land surface. More careful interpretation of the intervals that shallow and deep piezometers and shallow and deep bores are sampling indicates that variability in water chemistry between holes can, in part, be explained because they are sampling different materials in the sub-surface geology/regolith geology. Quartz is a relatively resistant phase throughout the profiles. For both substrates there is a decrease in the feldspar in increasingly weathered regolith materials, with a corresponding increase in kaolinite clay. There is increased homogenisation of the profile, and some horizonation due to pedogenic processes (e.g. bioturbation, illuviation of fines down profile) nearer the land surface. This results in a concentration of more resistant phases (quartz and remnant primary feldspar as sands) at the land surface over the granitic substrate, however kaolinite persists in the profile over the finer substrate. The presence of measurable ferruginous oxides and sesquioxides relates to localised percolation of oxidising fluids through the profiles. Understanding the configuration and composition of rocks and regolith materials in the Baldry catchment facilitates interpretation of observed patterns in hydrological analyses.

Bernardi, Tony

2014-05-01

200

Hydrograph prediction in ungauged basins - a comparative assessment of studies  

NASA Astrophysics Data System (ADS)

The objective of this assessment is to compare studies predicting runoff hydrographs in ungauged catchments. The aim is to learn from the similarities and differences between catchments in different places, and to interpret the differences in performance in terms of the underlying climate-landscape controls. The assessment is performed at two levels. The Level 1 assessment is a meta-analysis of 33 studies reported in the literature involving 3874 catchments. The Level 2 assessment consists of a more focused and detailed analysis of individual basins from selected studies from Level 1 in terms of how the leave-one-out cross-validation performance depends on climate and catchment characteristics as well as on the chosen regionalisation method. The results indicate that runoff hydrograph predictions in ungauged catchments tend to be more accurate in humid than in arid catchments and more accurate in large than in small catchments. The dependence of performance on elevation differs by regions and depends on how aridity varies with elevation and air temperature. The effect of parameter regionalisation method on model performance differs between studies. However, there is a tendency towards a somewhat lower performance of regressions than other methods in those studies that apply different methods in the same region. In humid catchments spatial proximity and similarity methods perform best while in arid catchments similarity and parameter regression methods perform slightly better. For studies with a large number of catchments (dense stream gauge network) there is a tendency for spatial proximity and geostatistics to perform better than regression or regionalisation based on simple averaging of model parameters from gauged catchments. There was no clear relationship between predictive performance and the number of regionalised model parameters. The implications of the findings are discussed in the context of model building.

Parajka, Juraj; Viglione, Alberto; Rogger, Magdalena; Salinas, Jose Luis; Sivapalan, Murugesu; Bloeschl, Guenter

2013-04-01

201

Quantifying the controls on grain size export from tectonically perturbed catchments: Case studies from Sicily, Calabria and Abruzzo, Italy  

NASA Astrophysics Data System (ADS)

The magnitude, locus and characteristics of sediment export from catchments to neighbouring basins plays a significant role in controlling depositional stratigraphy. Fundamentally, the boundary conditions for sediment release from catchments are set by tectonics and climate, modulated by lithologic, hydrologic and geomorphic controls operating over the relevant time or length scale. A predictive understanding of sediment export to basins therefore requires (i) the integration of data illustrating the characteristics of sediment delivery within catchments and (ii) detailed constraints on how this supply signal evolves down-system, for a wide range of controlling variables. Here we address this challenge. Firstly, we present a detailed data study linking hillslope sediment supply to trunk stream grain size evolution for three catchments with drainage areas > 30 km2 in northern Sicily where tectonic uplift rates are > 1 mm/yr and where lithologies are well-mapped, using both sieved weight fraction and Wolman point count methodologies. We find that sediment input from coarse debris flows, rather than landslides, plays a dominant role in setting channel grain size and that coarse-fraction sediment export from catchments is intimately linked to channel-hillslope geomorphic coupling. Secondly, we present detailed data on grain size export from the outlets of more than 40 tectonically perturbed catchments across Sicily, Calabria and Abruzzo, where we have excellent constraints on tectonic uplift rates, lithology and catchment hydraulic geometry. We demonstrate that for catchments in topographic steady-state, grain size release is strongly controlled by rock type, but is insensitive to drainage area and local uplift rates that are < 1 mm/yr. In contrast, for catchments responding transiently to tectonics, the calibre of sediment release is strongly controlled by the degree of tectonic perturbation. The southern Italian data-sets allow us to provide first order estimates of the volume and grain size distribution of sediment exported to the straits of Messina as a whole, and we use terrace data to show there has been little change to this sediment release signal in the last 200 kyr. Together, these results allow us to evaluate the relative importance of upstream source controls in setting the characteristics of sediment release from tectonically perturbed catchments to basins and provide new data to test the outputs of sediment routing system models.

Whittaker, A.; Erhardt, S.; Norori-McCormac, A.; Knight, F.

2012-04-01

202

The impact of land management in agricultural catchments on groundwater pollution levels  

NASA Astrophysics Data System (ADS)

Agricultural activity results in water pollution from nitrogen and phosphorus compounds. Increased concentrations of nitrogen compounds pose a threat to animal and human health. The purpose of this study was to determine the impact of agriculture in a catchment basin on the level of groundwater pollution from biogenic compounds. Spatial analysis of the land cover was conducted using a GIS and was based on data from the Corine Land Cover databases.

Matysik, Magdalena

2014-10-01

203

The geography of the Humber catchment  

Microsoft Academic Search

The geography of the Humber catchment is described in relation to the varied geology, relief, resources, industrial structure and location, agriculture and population distribution. The review of catchment characteristics is set within an historical perpective, with an evaluation of current and possible future trends in agriculture, population, industry and possible implications for river water quality.

Helen P. Jarvie; Colin Neal; Alice J. Robson

1997-01-01

204

Storage as a Metric of Catchment Comparison  

USGS Publications Warehouse

The volume of water stored within a catchment, and its partitioning among groundwater, soil moisture, snowpack, vegetation, and surface water are the variables that ultimately characterize the state of the hydrologic system. Accordingly, storage may provide useful metrics for catchment comparison. Unfortunately, measuring and predicting the amount of water present in a catchment is seldom done; tracking the dynamics of these stores is even rarer. Storage moderates fluxes and exerts critical controls on a wide range of hydrologic and biologic functions of a catchment. While understanding runoff generation and other processes by which catchments release water will always be central to hydrologic science, it is equally essential to understand how catchments retain water. We have initiated a catchment comparison exercise to begin assessing the value of viewing catchments from the storage perspective. The exercise is based on existing data from five watersheds, no common experimental design, and no integrated modelling efforts. Rather, storage was estimated independently for each site. This briefing presents some initial results of the exercise, poses questions about the definitions and importance of storage and the storage perspective, and suggests future directions for ongoing activities. ?? 2011 John Wiley & Sons, Ltd.

Mcnamara, J. P.; Tetzlaff, D.; Bishop, K.; Soulsby, C.; Seyfried, M.; Peters, N. E.; Aulenbach, B. T.; Hooper, R.

2011-01-01

205

An uncertainty assessment of discharge projections for eight Swiss catchments  

NASA Astrophysics Data System (ADS)

Projections of discharge under future climate are impaired by uncertainties arising from different sources: the emission scenarios, the climate models, the post-processing of the climate projections, the hydrological models structure and parameterisation. In this project we investigated the contribution of each of these sources to the final simulation uncertainty for discharge using analyses of variance (ANOVA) in eight catchments representative of the typical Swiss discharge regimes. The catchments are distributed among the Jura, the Swiss Plateau and the Alps, and are known to react differently to climate change. We used climate projections of the CH2011 dataset obtained from the Center for Climate Systems Modeling (C2SM). This dataset consists of two types of projections, both based on the climate model runs of the ENSEMBLES project: one relies on the delta change technique applied to 10 runs and the other is based on a Bayesian multi-model approach combining 20 runs until 2050, and then 14 runs until 2099. In addition to the climate projections for emission scenario A1B chosen for the ENSEMBLES project, the CH2011 team generated simulations for the scenarios A2 and RCP3PD using pattern scaling. This enabled us to address the influence of the uncertainty in green house gases emissions on discharge projections. We ran hydrological simulations using three conceptual models: HBV, PREVAH and WaSiM. HBV and PREVAH rely on a similar reservoir structure, while WaSiM uses the process-oriented Richards-equation approach. PREVAH and WaSiM use a higher level of spatial discretization than the lumped HBV model. The use of the three different models allowed evaluation of the sensitivity of discharge projections to the hydrological model complexity and structure. Simulations were run for the periods 2020-2049, 2045-2074 and 2070-2099 to assess the variation of the different sources of uncertainty over time. The pattern scaling enabled the assessment of uncertainty arising from the emission scenarios in ENSEMBLES simulations and preliminary results suggest that this uncertainty is dominant by the end of the century for the majority of the catchments. Furthermore, in contrast to similar studies on uncertainty quantification that focus on a single catchment or geographic region, our setting demonstrates that the respective contribution of the different sources of uncertainty varies with catchment properties.

Addor, Nans; Rössler, Ole; Köplin, Nina; Bernhard, Luzi; Bosshard, Thomas; Weingartner, Rolf; Seibert, Jan

2013-04-01

206

Preliminary study of land-plant biomarkers in marine sediments of Alfonso basin and its relationship with the climate of the last 3.5 ka  

NASA Astrophysics Data System (ADS)

This study used biomarkers such as n-alkanes, especially focused on the long chain n-alkanes and some diagnostic indexes derived from abundance, to elucidate molecular changes in the contribution of organic matter to the sediments, especially terrestrial vegetation surrounding continental areas around of Alfonso basin in response to climate change, particularly changes in the hydrological cycle. The results show that in general the n-alkanes of organic matter (OM) of Alfonso basin sediments are composed of a mixture of waxes derived from phytoplankton and terrestrial plants, with a greater contribution from phytoplankton compare to terrestrial vegetation, in the oldest part of the record, associated with a marine productivity increased period favored by rainfall. Maximum abundance of C29, and high values of C27/C31 ratio indicate leaves from trees as a source wax, probably succulents plants characteristic of arid zones, with C3 as one of their metabolic pathway, identified from mean ACL values around 29.5. The low CPI index indicates contamination and microbial communities as a possible source of long chain n-alkanes, probably due to anoxic bottom conditions in Alfonso basin favor the development of these communities. Finally, it is suggested no change in the community, at least for the last ~ 3.5 ka BP, but increased cover vegetation (biomass) in southern California during periods of increased rainfall (from ~ 3.5 to ~ 1.7 ka BP). The ability of terrestrial plant communities to adapt for longer periods before being replaced by other species, when faced with gradual changes rather than rapid climate change is reflected in a few changes in its composition.

Ricaurte-Villota, Constanza; Gonzalez-Yajimovich, Oscar; Betancourt-Portela, Julian

2014-05-01

207

Hydrogeochemical responses of forested catchments  

NASA Astrophysics Data System (ADS)

The AGU Chapman Conference on Hydrogeochemical Responses of Forested Catchments was held September 18-21, 1989, in Bar Harbor, Maine, and brought together geochemists with interests in determining the effects of different geochemical processes on resulting surface water chemistry and hydrologists with interests in explaining flow generation in catchments with the aim of fostering better communication between the two groups on the topic of geochemical and hydrological interactions in intermediate-size watersheds. An important point of consideration was the emphasis on intermediate-size watersheds, which we defined operationally as watersheds of sufficient size to yield flow and habitat suitable for supporting at least a marginal recreational fishery, for example, on the order of at least a few square kilometers in the northeast United States. This emphasis is important because it is the potential effects of pollutants, as modified by watershed geochemical and hydrological processes, in watersheds of this scale that drive much of the concern of the nation's regulatory agencies with regard to adverse environmental effects and required water quality legislation. A good example of this is the current concern over potential adverse effects of acidic deposition on surface water quality, especially in streams that support upland sport fisheries.

Robbins Church, M.; Hornberger, George; Driscoll, Charles; Sklash, Michael; Hemond, Harold

208

Coupling soil moisture and precipitation observations for predicting hourly runoff at small catchment scale  

NASA Astrophysics Data System (ADS)

The importance of soil moisture is recognized in rainfall-runoff processes. This study quantitatively investigates the use of soil moisture measured at 10, 20, and 40 cm soil depths along with rainfall in predicting runoff. For this purpose, two small sub-catchments of Tiber River Basin, in Italy, were instrumented during periods of October 2002-March 2003 and January-April 2004. Colorso Basin is about 13 km2 and Niccone basin 137 km2. Rainfall plus soil moisture at 10, 20, and 40 cm formed the input vector while the discharge was the target output in the model of generalized regression neural network (GRNN). The model for each basin was calibrated and tested using October 2002-March 2003 data. The calibrated and tested GRNN was then employed to predict runoff for each basin for the period of January-April 2004. The model performance was found to be satisfactory with determination coefficient, R2, equal to 0.87 and Nash-Sutcliffe efficiency, NS, equal to 0.86 in the validation phase for both catchments. The investigation of effects of soil moisture on runoff prediction revealed that the addition of soil moisture data, along with rainfall, tremendously improves the performance of the model. The sensitivity analysis indicated that the use of soil moisture data at different depths allows to preserve the memory of the system thus having a similar effect of employing the past values of rainfall, but with improved GRNN performance.

Tayfur, Gokmen; Zucco, Graziano; Brocca, Luca; Moramarco, Tommaso

2014-03-01

209

Attributes for NHDplus Catchments (Version 1.1) for the Conterminous United States: Population Density, 2000  

USGS Publications Warehouse

This data set represents the average population density, in number of people per square kilometer multiplied by 10 for the year 2000, compiled for every catchment of NHDPlus for the conterminous United States. The source data set is the 2000 Population Density by Block Group for the Conterminous United States (Hitt, 2003). The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States. The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, contains NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus Production Units 4, 5, 7 and 9. MRB4, covering the Missouri River basins, contains NHDPlus Production Units 10-lower and 10-upper. MRB5, covering the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins, contains NHDPlus Production Units 8, 11 and 12. MRB6, covering the Rio Grande, Colorado and Great Basin River basins, contains NHDPlus Production Units 13, 14, 15 and 16. MRB7, covering the Pacific Northwest River basins, contains NHDPlus Production Unit 17. MRB8, covering California River basins, contains NHDPlus Production Unit 18.

Wieczorek, Michael E.; LaMottem, Andrew E.

2010-01-01

210

A New Tool to Facilitate Sustainable Catchment Management  

Microsoft Academic Search

A new approach to collating and processing catchment data has been developed. A Catchment Information Management System was developed as a user-friendly catchment management tool for use by DWAF personnel and other stakeholders. This tool can be used to monitor and manage the water resource status of the catchment, as well as assist with strategic planning. This tool was developed

Herman Wiechers; Fred Sutherland; Julie Borland; Reynie Reyneke; Kavita Pema; Dawie Maree; Marius Keet; Marietjie Eksteen

211

A maximum entropy view of probability-distributed catchment models  

Microsoft Academic Search

The probability-distributed catchment model, as originally proposed by Moore & Clarke (1981), is re-examined from a maximum statistical entropy viewpoint. The distribution of water within a catchment is treated as a problem of statistical inference and resolved using an entropy maximization technique. A simple runoff generating mechanism is employed, which, together with the catchment mass balance equation, yields a catchment

PAUL W. JOWITT

1991-01-01

212

Data-based information gain on the response behaviour of hydrological models at catchment scale  

NASA Astrophysics Data System (ADS)

A data-based approach is presented to analyse the response behaviour of hydrological models at the catchment scale. The approach starts with a number of sequential time series processing steps, applied to available rainfall, ETo and river flow observation series. These include separation of the high frequency (e.g., hourly, daily) river flow series into subflows, split of the series in nearly independent quick and slow flow hydrograph periods, and the extraction of nearly independent peak and low flows. Quick-, inter- and slow-subflow recession behaviour, sub-responses to rainfall and soil water storage are derived from the time series data. This data-based information on the catchment response behaviour can be applied on the basis of: - Model-structure identification and case-specific construction of lumped conceptual models for gauged catchments; or diagnostic evaluation of existing model structures; - Intercomparison of runoff responses for gauged catchments in a river basin, in order to identify similarity or significant differences between stations or between time periods, and relate these differences to spatial differences or temporal changes in catchment characteristics; - (based on the evaluation of the temporal changes in previous point:) Detection of temporal changes/trends and identification of its causes: climate trends, or land use changes; - Identification of asymptotic properties of the rainfall-runoff behaviour towards extreme peak or low flow conditions (for a given catchment) or towards extreme catchment conditions (for regionalization, ungauged basin prediction purposes); hence evaluating the performance of the model in making extrapolations beyond the range of available stations' data; - (based on the evaluation in previous point:) Evaluation of the usefulness of the model for making extrapolations to more extreme climate conditions projected by for instance climate models. Examples are provided for river basins in Belgium, Ethiopia, Kenya, Ecuador, Bolivia and China. References: Van Steenbergen, N., Willems, P. (2012), 'Method for testing the accuracy of rainfall-runoff models in predicting peak flow changes due to rainfall changes, in a climate changing context', Journal of Hydrology, 414-415, 425-434, doi:10.1016/j.jhydrol.2011.11.017 Mora, D., Willems, P. (2012), 'Decadal oscillations in rainfall and air temperature in the Paute River Basin - Southern Andes of Ecuador', Theoretical and Applied Climatology, 108(1), 267-282, doi:0.1007/s00704-011-0527-4 Taye, M.T., Willems, P. (2011). 'Influence of climate variability on representative QDF predictions of the upper Blue Nile Basin', Journal of Hydrology, 411, 355-365, doi:10.1016/j.jhydrol.2011.10.019 Taye, M.T., Willems, P. (2012). 'Temporal variability of hydro-climatic extremes in the Blue Nile basin', Water Resources Research, 48, W03513, 13p. Vansteenkiste, Th., Tavakoli, M., Ntegeka, V., Willems, P., De Smedt, F., Batelaan, O. (in press), 'Climate change impact on river flows and catchment hydrology: a comparison of two spatially distributed models', Hydrological Processes; doi: 10.1002/hyp.9480 [in press

Willems, Patrick

2013-04-01

213

Quantifying denudation rates in Mediterranean margin catchments: the Gulf of Lion and East-Corsica case-study  

NASA Astrophysics Data System (ADS)

Margins are the place of transfer, deposit and erosion of sediments whose geometries are controlled by sea-level fluctuations, vertical movements and sedimentary fluxes. Surface processes (sedimentation, denudation) and deep-sea dynamic are also intimately linked. Due to the numerous data acquired over the last 10 years, the Gulf of Lion and East-Corsica margins could be considered as privileged studied areas to understand the relationships between denudation, sedimentation and associated vertical displacements. The quantification of denudation rates on these margins catchments, using offshore and onshore data aims to improve the understanding of the temporal and spatial evolution of denudation processes in their sedimentation and geodynamic evolution in a large basin (Gulf of Lion) and in a small confined basin (Golo margin; East-Corsica) during the Quaternary. The Gulf of Lion is the northern passive margin of the Liguro-provençal basin, in western Mediterranean Sea. During the Quaternary, it receives sediments from catchments draining several structural domains, as Alps, Pyrenees and Massif Central, for a drainage area of about 120,000 km^2. The East-Corsica corresponds to the western passive margin of the Tyrrhenian basin. The main catchment (Golo River) size is about 100 times smaller than the Gulf of Lion and is composed by two main structural units: Hercynian granites in the upstream part and Alpine schists in the downstream part. In this study, we quantified Quaternary denudation rates using four independent methods: i) estimation of eroded volumes using DEMs; ii) compilation of present-day sediment load fluxes; iii) determination of catchment-scale cosmogenic denudation rate by measuring 10Be concentrations in sands at the catchment outlets or buried in boreholes; iv) quantification of sediment volumes deposited offshore. Our results show a good consistence between the four methods. The Inner Alps present the highest values of denudation (~ 700 m/Ma), compared to averaged much lower values in other domains (150-250 m/Ma in foreland Alps, 100-150 m/Ma in Corsica, about 100 m/Ma in Pyrenees and 55-75 m/Ma in Massif Central). The alpine domain provides at least 75 % of the eroded volume in the Gulf of Lion catchment. A quantitative geomorphologic approach highlights the main role of denudation processes in relief evolution for both studied areas. At a regional scale (Gulf of Lion catchment), we highlight an exponential correlation between mean catchment elevation and denudation rates suggesting the main role of uplift in areas glaciated during the LGM in the control of denudation rates. At a more local scale (East-Corsica), denudation rates seem to rely on lithologic and structural control.

Molliex, S.; Rabineau, M.; Jouet, G.; Bourles, D. L.; Freslon, N.; Leroux, E.; Moreau, J.; Aslanian, D.; Vella, C.

2013-12-01

214

Parsimonious hydrological modeling of urban sewer and river catchments  

NASA Astrophysics Data System (ADS)

SummaryA parsimonious model of flow capable of simulating flow in natural/engineered catchments and at WWTP (Wastewater Treatment Plant) inlets was developed. The model considers three interacting, dynamic storages that account for transfer of water within the system. One storage describes the “flashy” response of impervious surfaces, another pervious areas and finally one storage describes subsurface flow. The sewerage pipe network is considered as an impervious surface and is thus included in the impervious surface storage. In addition, the model assumes that water discharged from several CSOs (combined sewer overflows) can be accounted for using a single, characteristic CSO. The model was calibrated on, and validated for, the Vidy Bay WWTP, which receives effluent from Lausanne, Switzerland (population about 200,000), as well as for an overlapping urban river basin. The results indicate that a relatively simple approach is suitable for predicting the responses of interacting engineered and natural hydrosystems.

Coutu, Sylvain; Del Giudice, Dario; Rossi, Luca; Barry, D. A.

2012-09-01

215

Estimating catchment evaporation and runoff using MODIS leaf area index and the Penman-Monteith equation  

NASA Astrophysics Data System (ADS)

This paper shows the feasibility of using steady state water balances of gauged catchments to calibrate a spatially explicit evaporation model and then applying this to estimate mean annual runoff for 120 gauged catchments in the Murray-Darling Basin (MDB) of Australia from 2001 to 2005. We used remotely sensed leaf area indices from the Moderate Resolution Imaging Spectrometer (MODIS) mounted on the polar-orbiting Terra satellite with the Penman-Monteith equation, gridded meteorology, and a two-parameter biophysical model for surface conductance (Gs) to estimate 8-day average evaporation at 1-km resolution. Parameters for the Gs model were optimized using steady state water balance estimates (precipitation minus runoff) in the gauged catchments in three precipitation zones of the MDB, and the calibrated evaporation model was then used to estimate evaporation (ERS) and runoff from gauged and ungauged catchments in the MDB. Mean annual calibrated estimates of ERS compared well with water balance estimates, indicated by a root-mean-square error (RMSE) of 78.6 mm/a and the Nash-Sutcliffe coefficient of efficiency (CE) of 0.68. Reasonable agreement was obtained between the estimated mean annual runoff (RRS) (rainfall minus ERS), and the measured runoff (RMSE = 71.0 mm/a and CE = 0.75). Cross validation showed that estimated ERS and RRS were almost as good as the calibrated ones. Furthermore, RRS has an accuracy similar to that of a seven-parameter conceptual rainfall-runoff model in the gauged catchments. The results show that the evaporation model can be easily applied to estimate steady state evaporation and runoff and that ERS can be used with rainfall-runoff models to improve accuracy of estimated runoff in ungauged catchments.

Zhang, Y. Q.; Chiew, F. H. S.; Zhang, L.; Leuning, R.; Cleugh, H. A.

2008-10-01

216

SWAT model application in a data scarce tropical complex catchment in Tanzania  

NASA Astrophysics Data System (ADS)

This study intended to validate the Soil and Water Assessment Tool (SWAT) model in data scarce environment in a complex tropical catchment in the Pangani River Basin located in northeast Tanzania. The validation process involved the model initialization, calibration, verification and sensitivity analysis. Both manual and auto-calibration procedures were used to facilitate the comparison of the results with past studies in the same catchment. For this study, some model parameters including Soil depth (SOL_Z) and Saturated hydraulic conductivity (SOL_K) were assumed uniform within the study catchment and were therefore lumped comprising the huge computation resource requirement of the SWAT model. Results indicated that the same set of important parameters was identified with or without the use of observed flows data. Some of the parameters had physical interpretation and could therefore relate directly to hydrological controlling factors within the catchment. Despite swapping ranking importance of parameters, these results suggest the suitability of the SWAT model for identifying hydrological controlling factors/parameters in ungauged catchments. Results of calibration and validation at the daily timescale gave moderately satisfactory Nash-Sutcliffe Coefficient of Efficiency (CE) of 54.6% for calibration and 68% for validation while simulated and observed mean annual flow discharges gave an Index of Volumetric Fit (IVF) of 100%. The study further indicated the improvement of model estimation when more reliable spatial representation of rainfall was used. Although in this study SWAT model has performed satisfactorily in data poor and complex catchment, the authors recommend a wider validation effort of the model before it is adopted for operational purpose.

Ndomba, Preksedis; Mtalo, Felix; Killingtveit, Aanund

217

Water Catchment and Storage Monitoring  

NASA Astrophysics Data System (ADS)

Sensors and Sensor Networks technologies provide the means for comprehensive understanding of natural processes in the environment by radically increasing the availability of empirical data about the natural world. This step change is achieved through a dramatic reduction in the cost of data acquisition and many orders of magnitude increase in the spatial and temporal granularity of measurements. Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) is undertaking a strategic research program developing wireless sensor network technology for environmental monitoring. As part of this research initiative, we are engaging with government agencies to densely monitor water catchments and storages, thereby enhancing understanding of the environmental processes that affect water quality. In the Gold Coast hinterland in Queensland, Australia, we are building sensor networks to monitor restoration of rainforest within the catchment, and to monitor methane flux release and water quality in the water storages. This poster will present our ongoing work in this region of eastern Australia. The Springbrook plateau in the Gold Coast hinterland lies within a World Heritage listed area, has uniquely high rainfall, hosts a wide range of environmental gradients, and forms part of the catchment for Gold Coast's water storages. Parts of the plateau are being restored from agricultural grassland to native rainforest vegetation. Since April 2008, we have had a 10-node, multi-hop sensor network deployed there to monitor microclimate variables. This network will be expanded to 50-nodes in February 2010, and to around 200-nodes and 1000 sensors by mid-2011, spread over an area of approximately 0.8 square kilometers. The extremely dense microclimate sensing will enhance knowledge of the environmental factors that enhance or inhibit the regeneration of native rainforest. The final network will also include nodes with acoustic and image sensing capability for monitoring higher level parameters such as fauna diversity. The regenerating rainforest environment presents a number of interesting challenges for wireless sensor networks related to energy harvesting and to reliable low-power wireless communications through dense and wet vegetation. Located downstream from the Springbrook plateau, the Little Nerang and Hinze dams are the two major water supply storages for the Gold Coast region. In September 2009 we fitted methane, light, wind, and sonar sensors to our autonomous electric boat platform and successfully demonstrated autonomous collection of methane flux release data on Little Nerang Dam. Sensor and boat status data were relayed back to a human operator on the shore of the dam via a small network of our Fleck™ nodes. The network also included 4 floating nodes each fitted with a string of 6 temperature sensors for profiling temperature at different water depths. We plan to expand the network further during 2010 to incorporate floating methane nodes, additional temperature sensing nodes, as well as land-based microclimate nodes. The overall monitoring system will provide significant data to understand the connected catchment-to-storage system and will provide continuous data to monitor and understand change trends within this world heritage area.

Bruenig, Michael; Dunbabin, Matt; Moore, Darren

2010-05-01

218

Integrated flow and temperature modeling at the catchment scale  

NASA Astrophysics Data System (ADS)

Changes in natural stream temperature levels can be detrimental to the health of aquatic ecosystems. Water use and land management directly affect the distribution of diffuse heat sources and thermal loads to streams, while riparian vegetation and geomorphology play a critical role in how thermal loads are buffered. In many areas, groundwater flow is a significant contribution to river flow, particularly during low flows and therefore has a strong influence on stream temperature levels and dynamics. However, previous stream temperature models do not properly simulate how surface water-groundwater dynamics affect stream temperature. A coupled surface water-groundwater and temperature model has therefore been developed to quantify the impacts of land management and water use on stream flow and temperatures. The model is applied to the simulation of stream temperature levels in a spring-fed stream, the Silver Creek Basin in Idaho, where stream temperature affects the populations of fish and other aquatic organisms. The model calibration highlights the importance of spatially distributed flow dynamics in the catchment to accurately predict stream temperatures. The results also show the value of including temperature data in an integrated flow model calibration because temperature data provide additional constraints on the flow sources and volumes. Simulations show that a reduction of 10% in the groundwater flow to the Silver Creek Basin can cause average and maximum temperature increases in Silver Creek over 0.3 °C and 1.5 °C, respectively. In spring-fed systems like Silver Creek, it is clearly not feasible to separate river habitat restoration from upstream catchment and groundwater management.

Loinaz, Maria C.; Davidsen, Hasse Kampp; Butts, Michael; Bauer-Gottwein, Peter

2013-07-01

219

Historical land use changes and their impact on sediment fluxes in the Balaton basin (Hungary)  

Microsoft Academic Search

Agricultural land use changes can influence soil erosion process. The objective of this study was to investigate impact of historical land use changes on soil erosion and sediment transport in the Kali Basin study area, a small catchment located in a national park at Lake Balaton, Hungary. The Kali Basin is of high landscape value where vine (Vitis spp.) growing

Gyozo Jordan; Anton van Rompaey; Peter Szilassi; Gabor Csillag; Chris Mannaerts; Tsehaie Woldai

2005-01-01

220

Water Environments: Anthropogenic Pressures and Ecosystem Changes in the Atlantic Drainage Basins of Brazil  

Microsoft Academic Search

Densely occupied drainage basins and coastal zones in developing countries that are facing economic growth are likely to suffer from moderate to severe environmental impacts regarding different issues. The catchment basins draining towards the Atlantic coast from northeastern to southern Brazil include a wide range of climatic zones and diverse ecosystems. Within its borders lies the Atlantic rain forest, significant

Marcia Marques; Monica F. da Costa; Maria Irles de O. Mayorga; Patrícia R. C. Pinheiro

2004-01-01

221

Influence of catchment characteristics, forestry activities and deposition on nitrogen export from small forested catchments  

Microsoft Academic Search

The ability to predict nitrogen export from forested catchments is essential in order to evaluate the effects of anthropogenic activities on the trophic status of lakes and sea areas, and to extrapolate the results to catchments from which no measurements are available. Data from 20 forested catchments (0.3–42 km2) in Finland and Sweden during the 10-year period 1979–88 were used

Ahti Lepistö; Lotta Andersson; Berit Arheimer; Karin Sundblad

1995-01-01

222

DEM-based analysis of landscape organization: 2) Application to catchment comparison  

NASA Astrophysics Data System (ADS)

The delineation of homogeneous landscape elements (or "hydrologic response units") is often a prerequisite in field investigations and the application of semi-distributed hydrologic (or coupled hydrologic and biogeochemical) models. Delineation and quantification of dominant landscape elements requires methods to extract the features from digital elevation data or other readily available information. It is often assumed that hillslope and riparian areas constitute the two most important and identifiable landscape units contributing to catchment runoff in upland humid catchments. In addition, we have found that that the degree of hillslope water expression in stormflow is partially a function of riparian to hillslope reservoir ratios and landscape organization. Therefore, we developed a simple approach for quantifying landscape organization and distributed riparian to hillslope area ratios (riparian buffer ratios), as described in the accompanying contribution. Here we use this method as a framework for comparing and classifying diverse catchments located in Europe, the U.S., and New Zealand. Based on the three catchments Maimai (New Zealand), Panola (Georgia) and Sleepers (Vermont) we obtained the following preliminary results: (1) Local area entering the stream channels was most variable at Maimai and consistently diffuse at Sleepers and Panola. Also the median local area entering the channel network was largest at Maimai and smallest at Sleepers and Panola. This demonstrates the degree of landscape dissection (highest for Maimai) and the concentration of hillslope inputs along the stream network. (2) Riparian areas were smallest at Maimai, larger at Sleepers, and largest at Panola. The combination of riparian zone extent and focused (Maimai) versus diffuse (Sleepers and Panola) hillslope inputs to riparian zones controls local riparian to hillslope area ratios (riparian buffer capacities). (3) Area was accumulated to a large extend in the channel heads in all catchments. At Sleepers about 75 percent of all area originated from sub-catchments of less than 5 ha, whereas this proportion was 50 and 40 percent at Panola and Maimai respectively.

Seibert, J.; McGlynn, B.

2003-04-01

223

Aquatic carbon and GHG losses via the aquatic pathway in an arctic catchment  

NASA Astrophysics Data System (ADS)

Based in Northwest Canada, the HYDRA project ('Permafrost catchments in transition: hydrological controls on carbon cycling and greenhouse gas budgets') aims to understand the fundamental role that hydrological processes play in regulating landscape-scale carbon fluxes. The project aims to determine a) the role of vegetation functional type in carbon uptake, turnover and allocation, b) how the same functional types influence the delivery of soil-derived carbon to surface waters, and c) how important the aquatic carbon and greenhouse gas (GHG) losses are relative to catchment scale terrestrial fluxes. Here we focus on the magnitude of the aquatic concentrations and fluxes, presenting results from the first year of field sampling. Concentrations of the greenhouse gases CO2, CH4 and N2O, as well as dissolved organic and inorganic carbon (DOC and DIC), will be presented from a range of freshwater types within the tundra landscape; sites include lakes, polygons and the 'Siksik' stream which drains the primary study catchment. Eight sampling locations were selected along the approximately 2km long Siksik stream to allow carbon and GHG concentrations to be considered within a set of nested subcatchments. This synoptic sampling regime, in combination with stable isotopes and major ion concentrations also measured at each sampling point, will allow inputs of carbon and GHGs to be traced to source areas within the catchment. Evasion and downstream export will also be calculated and preliminary results presented in the context of quantifying the relative importance of the aquatic pathway to the full catchment carbon and greenhouse gas budgets. This analysis will also allow an initial comparison between the relative importance of different water bodies within the catchment, highlighting spatial hotspots to be prioritized in future campaigns.

Dinsmore, Kerry; Billett, Mike; Lessels, Jason; Street, Lorna; Wookey, Philip; Baxter, Robert; Subke, Jens-Arne; Tetzlaff, Doerthe

2014-05-01

224

Integration of sewer system maps in topographically based sub-basin delineation in suburban areas  

NASA Astrophysics Data System (ADS)

Due to the increase of urbanization, suburban areas experience a fast change in land use. The impact of such modifications on the watershed hydrological cycle must be quantified. To achieve this goal, distributed hydrological models offer the possibility to take into account land use change, and more particularly to consider urbanized areas and anthropogenic features such as roads or ditches and their impact on the hydrological cycle. A detailed definition of the hydrographical drainage network and a corresponding delineation of sub-basins is therefore necessary as input to distributed models. Sub-basins in natural catchments are usually delineated using standard GIS based terrain analysis. The drainage network in urbanised watersheds is often modified, due to sewer systems, ditches, retention basins, etc.. Therefore, its delineation is not only determined by topography. The simple application of terrain analysis algorithms to delineate sub-basins in suburban areas can consequently lead to erroneous sub-basin borders. This study presents an improved approach for sub-basin delineation in suburban areas. It applies to small catchments connected to a sewage plant, located outside the catchment boundary. The approach assumes that subsurface flow follows topography. The method requires a digital elevation model (DEM), maps of land use, cadastre, sewer system and the location of measurement stations and retention basins. Firstly, the topographic catchment border must be defined for the concerning flow measurement station. Standard GIS based algorithms, like the d8-flow direction algorithm (O'Callaghan and Mark, 1984) can be applied using a high resolution DEM. Secondly, the artificial catchment outlets have to be determined. Each catchment has one natural outlet - the measurement station on the river- but it can have several artificial outlets towards a sewage station. Once the outlets are determined, a first approximation of the "theoretical maximal contributing area" can be made. It encompasses the whole connected sewer system and the topographic catchment boundary. The area of interest is therefore defined. The next step is the determination of the extended drainage network, consisting of the natural river, ditches, combined and separated sewer systems and retention basins. This requires a detailed analysis of sewer system data, field work (mapping of ditches and inlets into the natural river). Contacts with local authorities are also required to keep up-to-date about recent changes. Pure wastewater and drinking water pipes are not integrated in the drainage network. In order to have a unique drainage network for the model, choices might have to be made in case of several coexisting drainage pipes. The urban sub-basins are then delineated with the help of a cadastral map (Rodriguez et al., 2003) or an aerial photography. Each cadastral unit is connected to the closest drainage pipe, following the principle of proximity and gravity. The assembly of all cadastral units connected to one network reach represents one urban sub-basin. The sub-basins in the rural part are calculated using the d8 flow direction and watershed delineation algorithm with "stream burning" (Hutchinson, 1989). One sub-basin is delineated for each reach of the extended drainage network. Some manual corrections of the calculated sub-basins are necessary. Finally, the urban and rural sub-basins are merged by subtraction of the urban area from the rural area and subsequent union of both maps. This method was applied to the Chaudanne catchment, a sub-basin of the Yzeron catchment (ca. 4 km2) in the suburban region of Lyon city, France. The method leads to a 30 % extended catchment area, as compared to the topographic catchment area. For each river inlet the sub-basin area could be determined, as well as for each retention basin. This information can be directly used for the dimensioning of retention basins, pipe diameters, etc.

Jankowfsky, Sonja; Branger, Flora; Braud, Isabelle; Rodriguez, Fabrice

2010-05-01

225

Preliminary report on fluid inclusions from halites in the Castile and lower Salado formations of the Delaware Basin, southeastern New Mexico. [Freezing-point depression  

SciTech Connect

A suite of samples composed primarily of halite from the upper Castile and lower Salado Formations of the Permian Basin was selected from Waste Isolation Pilot Plant (WIPP) core for a reconnaissance study of fluid inclusions. Volume percent of these trapped fluids averaged 0.7% to 1%. Freezing-point depressions varied widely and appeared to be unrelated to fluid-inclusion type, to sedimentary facies, or to stratigraphic depth. However, because very low freezing points were usually associated with anhydrite, a relation may exist between freezing-point data and lithology. Dissolved sulfate values were constant through the Castile, then decreased markedly with lesser depth in the lower Salado. This trend correlates very well with observed mineralogy and is consistent with an interpretation of the occurrence of secondary polyhalite as a result of gypsum or anhydrite alteration with simultaneous consumption of dissolved sulfate from the coexisting fluids. Together with the abundance and distribution of fluid inclusions in primary or ''hopper'' crystal structures, this evidence suggests that inclusions seen in these halites did not migrate any significant geographical distance since their formation. 28 refs., 17 figs., 2 tabs.

Stein, C.L.

1985-09-01

226

Water Quality Modeling in Kranji Catchment  

E-print Network

This thesis describes the process and results of applying the Soil and Water Assessment Tool (SWAT) to characterize bacterial fate and transport in the Kranji Catchment of Singapore. The goal of this process is to predict ...

Granger, Erika C

2010-01-01

227

Erosion rates in the Rio La Paz drainage basin: evidence for spatially and temporally variable erosion processes  

NASA Astrophysics Data System (ADS)

With a total drainage area of 4850 km2 the morphometry of the La Paz drainage basin in the Bolivian Altiplano results from a combination of feedback mechanisms involving erosion and crustal bending. Apart from the Rio Consata the Rio de La Paz constitutes the only drainage system sourced on the Altiplano that cuts across the eastern Altiplano boundrary in the Cordillera Real and links this region with Amazonia. The fluvial network therefore connects geomorphically and geologically very different zones: 1) the virtually flat Altiplano with its Mio-Pliocene fluvio-lacustrine deposits and volcanics, 2) the high Cordillera, mainly comprised of Paleozoic metasediments, Mesozoic plutons, and Miocene volcanics, and 3) the folded sedimentary rocks of foothills of the Subandean zone. Cross-cutting relationships between dated strata and incised valleys indicate that incision in the Rio La Paz headwaters postdates 5 Ma, and possibly even 2.8 Ma. The volume of about 3950 km3, which has been evacuated since then (assuming 2.8 Ma as starting point of incision) by the Rio La Paz drainage system to the Rio Beni relates to an average erosion rate of 290 mm/ky. In order to investigate this long-term erosion rate with respect to possible spatial and temporal variations, we studied catchment-wide erosion rates in the Rio La Paz basin and contributing areas of adjacent subbasins using terrestrial cosmogenic nuclides (TCN). This method allows the determination of catchment-wide erosion rates from sediments being currently exported from the basin over timescales ranging from 1-10ky. Our preliminary results reveal an erosion rate of 230 mm/ky for the entire Rio La Paz basin (sample from basin outlet). Subbasin erosion rates vary from ca. 100 up to 600 mm/ky. So far, no direct correlation of mean slopes (and other morphometric parameters) in the subbasins and their respective erosion rates are obvious. However, there is a trend that the subbasins with high erosion rates are located close to the Cordillera, whereas subbasins with low erosion rates are located in immediate vicinity of the Altiplano. Present-day erosion rates in the Rio La Paz catchment obtained for a time frame spanning a decade range from 600-6000 mm/ky, based on sediment-yield data from published data, which is significantly higher than the ones revealed with TCN and the long-term volume estimates. The strong increase in the most recent erosion rates is most likely caused by human land-use practices (e.g. deforestation). The different roles of erosion processes (e.g. headwater expansion by landsliding and / or fluvial incision) and relief might be a cause for spatially variable erosion rates. In contrast, on the Altiplano west of the Rio La Paz drainage divide, erosion rates are one to two orders of magnitude lower than in the Rio La Paz catchment (Hippe et al. in prep.). In summary, the TCN results from the interior parts of the Rio La Paz catchments indicate spatially and temporally variable climatic and tectonic signals along the margins of Earth's second largest plateau.

Zeilinger, G.; Kober, F.; Strecker, M.; Ivy-Ochs, S.; Kubik, P. W.; Hippe, K.

2009-04-01

228

Hydrology and sediment yield calibration for the Barasona reservoir catchment (Spain) using SWAT  

NASA Astrophysics Data System (ADS)

Hydrological and soil erosion models, as Soil and Water Assessment Tool (SWAT), have become very useful tools and increasingly serve as vital components of integrated environmental assessments that provide information outside of direct field experiments and causal observation. The purpose of this study was to improve the calibration of SWAT model to use it in an alpine catchment as a simulator of processes related to water quality and soil erosion. SWAT is spatially semi-distributed, agro-hydrological model that operates on a daily time step (as a minimum) at basin scale. It is designed to predict the impact of management on water, sediment and agricultural chemical yields in ungaged catchments. SWAT provides physically based algorithms as an option to define many of the important components of the hydrologic cycle. The input requirements of the model are used to describe the climate, soil properties, topography, vegetation, and land management practices. SWAT analyzes small or large catchments by discretising into sub-basins, which are then further subdivided into hydrological response units (HRUs) with homogeneous land use, soil type and slope. SWAT model (SWAT2009) coupled with a GIS interface (ArcSWAT), was applied to the Barasona reservoir catchment located in the central Spanish Pyrenees. The 1509 km2 agro-forestry catchment presents a mountain type climate, an altitudinal range close to 3000 meters and a precipitation variation close to 1000 mm/km. The mountainous characteristics of the catchment, in addition to the scarcity of climate data in the region, require specific calibration for some processes. Snowfall and snowmelt are significant processes in the hydrologic regime of the area and were calibrated in a previous work. In this work some of the challenges of the catchment to model with SWAT which affected the hydrology and the sediment yield simulation were performed as improvement of the previous calibration. Two reservoirs, a karst system which deviate water out of the catchment and a badland area were parameterized in the SWAT model to finally calibrate the hydrology and the sediment yield of the catchment. The model was manually calibrated by a process of trial and error. Model performance during the calibration was evaluated using several statistical parameters, such as the Nash-Sutcliffe efficiency coefficient (NSE) and average runoff volume deviation (Dv). The hydrology was calibrated using continuous measured streamflow data from two gauge stations. The sediment yield calibration was based in specific sediment yield calculated from bathymetric surveys in the Barasona reservoir. The introduction of these improvements in the model performed better results than previous simulations enhancing the calibration of SWAT for the Barasona catchment. The final calibration of the model allows modeling water and sediment production closer to reality and therefore the study of the catchment processes would be more reliable.

Palazón, Leticia; Navas, Ana

2013-04-01

229

Spectral Analysis in Catchment Hydrology and Geochemistry  

NASA Astrophysics Data System (ADS)

Spectral analysis of chemical tracer time series can be used to probe the internal workings of catchments. It has recently been shown that catchments act as fractal filters for inert chemical tracers like chloride, converting "white noise" rainfall chemistry inputs into fractal "1/f noise" runoff chemistry time series (Kirchner et al., 2000). This implies that catchments have long-tailed travel time distributions, and thus retain soluble contaminants for unexpectedly long timespans. Long-term monitoring data from North America, Britain, and Scandinavia show that this fractal behavior characterizes a wide array of catchments. How can this fractal scaling arise in such diverse settings? One can show that advection and dispersion of spatially distributed rainfall tracer inputs will generate fractal tracer time series, as long as the flow system is highly dispersive (Kirchner et al., in press). This implies that subsurface flow in small catchments is dominated by large conductivity contrasts, such as arise from macropores, fracture networks, and similar large-scale heterogeneities in subsurface conductivity. One can also use spectral methods to analyze long-term time series of water fluxes in rainfall and streamflow. Spectral analysis of hydrologic time series measures the downslope propagation of the hydraulic potential waves that mobilize runoff, whereas spectral analysis of tracer time series clocks the propagation of water itself through the catchment. Water fluxes in streamflow exhibit non-fractal scaling, instead of the fractal 1/f scaling shown by chemical tracers. These observations imply that hydrologic signals are transmitted downslope more rapidly, and with much less dispersion, than chemical tracer signals are. Thus small upland catchments transmit hydraulic potentials (which drive runoff) much less dispersively than they transport water itself. These observations provide important constraints for theoretical models of subsurface flow and transport in catchments.

Kirchner, J. W.; Feng, X.; Renshaw, C. E.; Neal, C.

2001-12-01

230

Chloride circulation in a lowland catchment and the formulation of transport by travel time distributions  

NASA Astrophysics Data System (ADS)

Travel times are fundamental catchment descriptors that blend key information about storage, geochemistry, flow pathways and sources of water into a coherent mathematical framework. Here we analyze travel time distributions (TTDs) (and related attributes) estimated on the basis of the extensive hydrochemical information available for the Hupsel Brook lowland catchment in the Netherlands. The relevance of the work is perceived to lie in the general importance of characterizing nonstationary TTDs to capture catchment transport properties, here chloride flux concentrations at the basin outlet. The relative roles of evapotranspiration, water storage dynamics, hydrologic pathways and mass sources/sinks are discussed. Different hydrochemical models are tested and ranked, providing compelling examples of the improved process understanding achieved through coupled calibration of flow and transport processes. The ability of the model to reproduce measured flux concentrations is shown to lie mostly in the description of nonstationarities of TTDs at multiple time scales, including short-term fluctuations induced by soil moisture dynamics in the root zone and long-term seasonal dynamics. Our results prove reliable and suggest, for instance, that drastically reducing fertilization loads for one or more years would not result in significant permanent decreases in average solute concentrations in the Hupsel runoff because of the long memory shown by the system. Through comparison of field and theoretical evidence, our results highlight, unambiguously, the basic transport mechanisms operating in the catchment at hand, with a view to general applications.

Benettin, Paolo; Velde, Ype; Zee, Sjoerd E. A. T. M.; Rinaldo, Andrea; Botter, Gianluca

2013-08-01

231

Understanding Pesticide Behaviour At The Catchment Scale  

NASA Astrophysics Data System (ADS)

Pesticides in stream flow at the outlet of a 142ha catchment in Eastern England (Col- worth, Bedfordshire), have been monitored since October 1999. About 50% of the total catchment is directly controlled within one farm and a rotation of wheat, oil seed rape, grass, linseed, beans and peas is grown. The data from this catchment are being used to investigate the performance of the USDA SWAT contaminant transport pack- age at the catchment scale. Three years of stream flow and climate data are available with a useful set of pesticide application and detection data. Following calibration and validation of the hydrology of the catchment, pesticide modelling was carried out for tebuconazole, terbutryn, and terbuthylazine. This paper reports on the results of a sen- sitivity analysis of the model, and the final calibrated pesticide component. Analysis of the results obtained show that the timing and decay of predicted pesticide concen- trations are correct. It is therefore recommended that SWAT can be used as a tool to understand pesticide behaviour at the catchment scale.

Kannan, N.; White, S. M.; Worrall, F.; Pendlington, D.; Groves, S.

232

Preliminary Basin Analysis of Latest Miocene Conglomerate Near Bahía Kino, Coastal Sonora: A New Record of Crustal Deformation During Initial Opening of the Northern Gulf of California  

NASA Astrophysics Data System (ADS)

In coastal Sonora northwest of Bahía Kino, we have initiated a basin-analysis study of nonmarine conglomerate (Tcg) that overlies and is locally interbedded with the 6.4-Ma Tuff of Mesa Cuadrada (Tmc). Tcg conglomerate is deeply eroded and cut by a complex set of syn- to post-basinal, N- to NNE-striking normal faults and NW-striking dextral strike-slip faults. We carried out detailed mapping and field descriptions, measured stratigraphic sections, and collected paleocurrent and clast-count data in Tcg. Zircons from the newly discovered Seri tuff near the base of the section, 160 m below Tmc, were dated using U-Pb SHRIMP geochronology at Stanford University. We obtained a 206Pb/238U weighted mean age of 6.53+/-0.18 Ma (n=14; MSWD=1.3), which yields a sediment-accumulation rate of 0.8+/-0.2 mm/yr for lower Tcg. Tcg is dominated by debris-flow facies consisting of massive, poorly sorted, weakly bedded, matrix-rich, pebble, cobble, to small-boulder conglomerate. A subsidiary sheet-flood facies is somewhat better sorted, generally lacks boulders, and contains weak but pervasive horizontal stratification. Both facies of Tcg record deposition in an alluvial fan environment. Well sorted and stratified stream deposits are conspicuously lacking. Preserved sections of Tcg range up to 170 to 240 meters thick in the southern part of the study area, and increase to at least 470 meters in the north where the Punta Chueca fault, a large NW-directed low-angle normal fault, apparently produced more extension and subsidence than smaller faults in the south. Clasts in Tcg are dominated by middle Miocene andesite, the 12.6-Ma Tuff of San Felipe, minor amounts of Tmc, and variable amounts of older basement rocks including tonalite, granodiorite, quartzite, metavolcanic rock, and a megacrystic K-spar-bearing granite that we have not seen in the local bedrock. After correcting for bedding dips and vertical-axis clockwise rotations determined from paleomagnetic analysis, restored paleocurrents reveal consistent overall transport to the SSW. We interpret Tcg to record deposition in a 10- to 20-km wide coastal belt of coalesced alluvial fans (bajadas) that formed on the margin of the nascent northern Gulf of California. Alluvial fans were likely derived from a large uplands source area NE of the Sacrificio fault that is now submerged beneath broad alluvial plains of the Rio Sonora. Prior to this time, between 12.5 and 6.5 Ma, extension caused tilting and erosion but did not produce significant crustal thinning or subsidence. The abrupt change to rapid subsidence and sedimentation in a belt of coastal alluvial fans records a major change in deformation style and crustal dynamics at about 6.5 Ma. We infer that this change coincides with the transition from pre-6.5 Ma diffuse regional extension (late Miocene proto-gulf stage) to rapid, localized latest Miocene oblique dextral shear that resulted from initiation or acceleration of plate-boundary strain in the northern Gulf of California. If this interpretation is correct, the onset of northern Gulf opening is thus dated at ca. 6.5 Ma.

Dorsey, R. J.; Peryam, T. C.; Bennett, S.; Oskin, M. E.; Iriondo, A.

2008-12-01

233

Geohydrology, water quality, and preliminary simulations of ground-water flow of the alluvial aquifer in the Upper Black Squirrel Creek basin, El Paso County, Colorado  

USGS Publications Warehouse

The upper Black Squirrel Creek basin in eastern El Paso County, Colorado, is underlain by an alluvial aquifer and four bedrock aquifers. Groundwater pumpage from the alluvial aquifer has increased since the mid-1950's, and water level declines have been substantial; the bedrock aquifers virtually are undeveloped. Groundwater pumpage for domestic, stock, agricultural, and municipal uses have exceeded recharge for the past 25 years. The present extent of the effect of pumpage on the alluvial aquifer was evaluated, and a groundwater flow model was used to simulate the future effect of continued pumpage on the aquifer. Measured water level declines from 1974 through 1984 were as much as 30 ft in an area north of Ellicott, Colorado. On the basis of the simulations, water level declines from October 1984 to April 1999 north of Ellicott might be as much as 20 to 30 ft and as much as 1 to 10 ft in most of the aquifer. The groundwater flow models provided a means of evaluating the importance of groundwater evapotranspiration at various stages of aquifer development. Simulated groundwater evapotranspiration was about 43% of the outflow from the aquifer during predevelopment stages but was less than 3% of the outflow from the aquifer during late-development stages. Analyses of 36 groundwater samples collected during 1984 indicated that concentrations of dissolved nitrite plus nitrate as nitrogen generally were large. Samples from 5 of the 36 wells had concentrations of dissolved nitrite plus nitrate as nitrogen that exceeded drinking water standards. Water from the alluvial aquifer generally is of suitable quality for most uses. (USGS)

Buckles, D.R.; Watts, K.R.

1988-01-01

234

Selenium and mining in the Powder River Basin, Wyoming: Phase III - a preliminary survey of selenium concentrations in deer mice (Peromyscus maniculatus) livers  

SciTech Connect

Samples of liver tissue from deer mice trapped on not-yet-mined areas and reclaimed areas at five surface coal mines in the Powder River Basin of northeastern Wyoming were analyzed for selenium. The overall mean concentration of selenium in wet weight liver tissue was 1.685 ppm. The mean value from not-yet-mined areas was 1.437 ppm; the mean value from reclaimed areas was 1.910 ppm (significant at p<0.1016). When one not-yet-mined outlier was removed, significance rose to p<0.0004. Mine-to-mine comparison of samples stratified by type (that is, by not-yet-mined or reclaimed), showed average tissue concentrations from the reclaimed area of Mine 1 were also higher (p<0.0143) then not-yet-mined area samples at Mine 1. No statistically significant differences were found between mines for samples from not-yet-mined areas, and no statistically significant differences were found between Mines 2, 3, 4, and 5 for samples from reclaimed areas. Multiple analysis of variance using the factors: site (mine) and type (not-yet-mined or reclaimed) was not significantly significant (p<0.2115). Simple linear regression showed that selenium concentrations in dry tissue could easily be predicted from wet tissue selenium (r2=0.9775), demonstrating that percent water in the samples was relatively constant. Animal body weight in general was not a predictor for either wet or dry tissue selenium concentrations, but was related to body weight at the higher tissue concentrations of selenium encountered in samples from the reclaimed area at Mine 1. Mouse body weights at Mine 1 were higher on the reclaimed area than mouse body weights from the not-yet-mined area.

Raisbeck, M.L.; Vance, G.F. [Univ. of Wyoming, Laramie, WY (United States); Steward, D.G. [AMAX Coal West, Inc., Gillette, WY (United States)] [and others

1995-09-01

235

Nutrient fluxes from the Danube basin to the Black sea  

Microsoft Academic Search

This paper deals with the state of the art of quantification of sources, pathways and sinks of nutrients in the Danube Basin and their transport form the catchment to the Black Sea. It shows main results of emission estimates to surface waters and the Danube Water Quality Model approach to link this emissions estimates to measured water monitoring data. The

M. Zessner; J. van Gils

236

Using scale-dependent observational data for snow modelling in a glacierized catchment  

NASA Astrophysics Data System (ADS)

Snow cover distribution and melt are essential to understand and to predict runoff. However, the spatial heterogeneity of snow cover in complex terrain and the limited availability of observational data make distributed modelling of snow covered area (SCA) and of snow water equivalent (SWE) in alpine regions still a challenging task. A promising approach is the application of physically based distributed hydrological models coupled with ground observations and with new satellite products. However, the inherent complexity of advanced models and satellite products requires an accurate evaluation both at plot and at catchment scale before their operational use. In this context we evaluate the capability of the new model GEOtop 2.0 for the first time to simulate snow dynamics at plot and at catchment scale. Our study was performed in the upper Saldur basin (61 km²) in the Eastern Italian Alps during the period 2010 - 2013. At plot scale, simulated snow depths and SWE were calibrated against measured snow depth data from multiple measuring sites at different elevations (at 1930 m, at 1998 m, at 2450 m, and 3035 m a.s.l.) in and close to the Saldur basin. The evaluation was quantified by the statistical indices R² and the Nash-Sutcliffe efficiency. Different model parameterisations were evaluated by a manual sensitivity analysis of 11 key parameters controlling the snowpack and the meteorological input data. Most of these key parameters found to be sensitive for SWE and for snow depth were the ones controlling albedo decreasing and precipitation input. At catchment scale, simulated SCA of the upper Saldur basin was calibrated against the daily composite 250 m EURAC MODIS SCA (Notarnicola et al. 2013) and then validated against Landsat 7 ETM+ SCA (at 30 m resolution). The model evaluation was supported by a pixel-based calculation of overall accuracy (Parajka and Blöschl 2008) of total SCA in the upper Saldur basin. Additionally, the snow presence derived from simulated SCA and MODIS SCA was evaluated against measured snow depth as ground truth data derived from the measuring sites. The same parameterisations, which were sensitive at plot scale showed good agreement with MODIS SCA, in particular for single snow events in autumn. These results confirm that model parameters were successfully transferred from plot scale to catchment scale. However, less agreement was found in zones with forest and steep slopes greater than 45°. Further investigations are needed to assess the uncertainties both of the hydrological model but also of the MODIS composite product in relation to different thresholds of snow depths and cloud cover. Keywords: snow cover, hydrological modelling, MODIS, plot and catchment scale, uncertainty.

Engel, Michael; Bertoldi, Giacomo; Endrizzi, Stefano; Notarnicola, Claudia; Niedrist, Georg; Comiti, Francesco

2014-05-01

237

Catchments as simple dynamical systems: A case study on methods and data requirements for parameter identification  

NASA Astrophysics Data System (ADS)

In many rainfall-runoff models at least some calibration of model parameters has to take place. Especially for ungauged or poorly gauged basins this can be problematic, because there is little or no data available for calibration. A possible solution to overcome the problems caused by data scarcity is to set up a measurement campaign for a short time period. With the employed approach based on the theory of Kirchner (2009), a model was developed and applied to the Rietholzbach catchment in Switzerland (Teuling et al., 2010, Seneviratne et al., 2012), with only two parameters. These two parameters describe a unique storage-discharge relation. The model is constructed such that the parameters can be determined not only with automatic calibration, but also by recession analysis and a priori from Boussinesq theory. The automatic calibration and the recession analysis have been fed with different selections of the full data record as well as with the full data record itself. For Boussinesq theory, catchment characteristics were given as required input. In the end, a comparison of the performance of the three different methods was made, and a comparison on the amount of data that is required by each of the three parameter identification methods. Melsen, L.A., Teuling, A.J., van Berkum, S.W., Torfs, P.J.J.F., Uijlenhoet, R. (2013) Catchments as simple dynamical systems: A case study on methods and data requirements for parameter identification, Water Resour. Res., under review References Kirchner, J.W. (2009), Catchments as simple dynamical systems: Catchment characterization, rainfall-runoff modeling, and doing hydrology backward, Water Resour. Res. 45:W02429. Seneviratne, S.I., I. Lehner, J. Gurtz, A.J. Teuling, H Lang, U. Moser, D. Grebner, L. Menzel, K. Schro, T. Vitvar, and M. Zappa (2012), Swiss prealpine Rietholzbach research catchment and lysimeter: 32 year time series and 2003 drought event, Water Resour. Res. 48:W06526. Teuling, A. J., I. Lehner, J. W. Kirchner, and S. I. Seneviratne (2010), Catchments as simple dynamical systems: Experience from a Swiss prealpine catchment, Water Resour. Res. 46: W10502.

Melsen, Lieke; Teuling, Adriaan; van Berkum, Sonja; Torfs, Paul; Uijlenhoet, Remko

2014-05-01

238

A detailed model for simulation of catchment scale subsurface hydrologic processes  

NASA Technical Reports Server (NTRS)

A catchment scale numerical model is developed based on the three-dimensional transient Richards equation describing fluid flow in variably saturated porous media. The model is designed to take advantage of digital elevation data bases and of information extracted from these data bases by topographic analysis. The practical application of the model is demonstrated in simulations of a small subcatchment of the Konza Prairie reserve near Manhattan, Kansas. In a preliminary investigation of computational issues related to model resolution, we obtain satisfactory numerical results using large aspect ratios, suggesting that horizontal grid dimensions may not be unreasonably constrained by the typically much smaller vertical length scale of a catchment and by vertical discretization requirements. Additional tests are needed to examine the effects of numerical constraints and parameter heterogeneity in determining acceptable grid aspect ratios. In other simulations we attempt to match the observed streamflow response of the catchment, and we point out the small contribution of the streamflow component to the overall water balance of the catchment.

Paniconi, Claudio; Wood, Eric F.

1993-01-01

239

Reservoir sedimentation and catchment sediment yield in the Strines catchment, U.K  

Microsoft Academic Search

Rates of sedimentation and sediment yield have been calculated for the Strines catchment, UK. Estimates of original reservoir capacity are compared with measured capacities in 1956, 1993 and 1994 and sediment yields calculated using an extensive survey of the bulk densities of reservoir sediments. Rates of sedimentation and catchment erosion are low in global terms but relatively high for the

P. White; D. P. Butcher; J. C. Labadz

1997-01-01

240

Hydrothermal deposits in the Southern Trough of Guaymas Basin, Gulf of California: Observations and Preliminary Results from the 2003 MBARI Dive Program  

NASA Astrophysics Data System (ADS)

During Leg 2 of the 2003 MBARI expedition to the Gulf of California, the ROV Tiburon completed eight dives to active vent fields in the Southern Trough of Guaymas Basin. Six venting areas were investigated in detail. Tiburon operations included (1) sampling mineral deposits that range from mini-chimneys a few centimeters high to 10-meter-tall sulfide-carbonate structures with wide flanges; (2) collection of 90C to 303C methane, carbon dioxide, and hydrogen-rich vent fluids in gas-tight samplers and plume-laden particulates in Niskin samplers; 3) collection of warm (up to 83C) hydrocarbon-rich sediment push cores; 4) long-term monitoring of three vent sites using thermocouple arrays (see adjacent Tivey et al poster) and osmotically-driven fluid samplers. Seventy days later, the ROV returned to recover the thermocouple arrays and ingrown chimneys. At the lowest temperature sites, fluid (up to 90C) discharged from orifices in sediment surrounded by white to yellow microbial mats. Combined Eh-ISUS (InSitu Ultraviolet Spectrophotometer) sensors mounted on Tiburon identified local increases in bisulfide and decreases in the oxidation/reduction potential (a proxy for methane and hydrogen sulfide) associated with these sites. Massive barite chimneys recovered from the margins of moderate-temperature vent sites are permeated with oil. Chimneys from higher temperature sites, in contrast, lack the liquid hydrocarbon component, and are largely composed of calcium carbonate with lesser anhydrite, amorphous silica, barite, pyrrhotite, Mg-silicate, galena, sphalerite, and chalcopyrite. Mineral precipitation at the southernmost site (Toadstool) is characterized by the formation of carbonate-rich flanges directly above a substrate of altered diatomaceous sediment. The upper sediment crust lies above a stockwork of calcite veins. High-temperature structures at Rebecca's Roost and Broken Mushroom have pagoda-like carbonate-rich flanges trapping pools of hydrothermal fluids that facilitate the growth of centimeter-thick layers of euhedral carbonate and pyrrhotite. Rapidly formed, anhydrite-rich chimneys are present at the summit of the pagoda structures. In-situ laser ablation Sr isotopic analyses of calcite and anhydrite indicate that minerals within flanges precipitate from vent fluids with less than 5% seawater dilution, whereas minerals within the more permeable anhydrite-dominant chimneys precipitate from mixtures of vent fluid with up to 70% seawater.

Stakes, D. S.; Tivey, M. K.; Koski, R. A.; Ortego-Osorio, A.; Preston, C. M.; McCulloch, M. T.; Nakamura, K.; Seewald, J.; Wheat, C. G.

2003-12-01

241

Impact of Climate Change on Hydrological Regimes and Water Resources Management in the Rhine Basin  

Microsoft Academic Search

The International Commission for the Hydrology of the Rhine basin (CHR) hascarried out a researchproject to assess the impact of climate change on the river flow conditionsin the Rhine basin. Along abottom-up line, different detailed hydrological models with hourly and dailytime steps have beendeveloped for representative sub-catchments of the Rhine basin. Along atop-down line, a water balancemodel for the entire

H. Middelkoop; K. Daamen; D. Gellens; W. Grabs; J. C. J. Kwadijk; H. Lang; B. W. A. H. Parmet; B. Schädler; J. Schulla; K. Wilke

2001-01-01

242

Relating variations in runoff to variations in climatic conditions and catchment properties  

NASA Astrophysics Data System (ADS)

We use the Budyko framework to calculate catchment-scale evapotranspiration (E)and runoff (Q) as a function of two climatic factors, precipitation (P) and evaporative demand (Eo = 0.75 times the pan evaporation rate), and a third parameter that encodes the catchment properties (n) and modifies how P is partitioned between E and Q. We use examples from the Murray-Darling Basin in Australia, and elsewhere, to examine the effects on run-off of perturbations to the underlying parameters. We include an examination of projections based on Intergovernmental Panel on Climate Change AR4 climate model output. We conclude that the modern version of the Budyko framework is a useful tool for making simple and transparent estimates of changes in water availability.

Farquhar, Graham; Sun, Fubao; Roderick, Michael

2013-04-01

243

Hydrological extreme events with Mike Basin  

NASA Astrophysics Data System (ADS)

This work is part of a broader project which aims to develop an integrated system to model and simulate of the hydrological cycle processes at river basin scale. All these processes involved in the dynamics of a watershed, which play an important role in the proper management and sustainable use of water resources, are influenced by many factors (e.g. soil use, vegetation cover, weather and climate) being of particular importance, all aspects related to the occurrence, amount and the spatial-temporal distribution of precipitation. We focus our work on the use of the MIKE Basin model and apply it to the Corgo River basin, which is a tributary of the Douro river, located in the Portuguese region of Trás-os-Montes and Alto Douro. Different datasets were used to characterize and model the river basin catchment hydrological processes, namely temperature, precipitation and runoff registered in several weather/hydrometric stations from the Institute of Information System for Water Resources (http://snirh.pt/) as well as land use/soil occupation and topography maps. The MIKE BASIN model runs on a Geographic Information System (GIS) to perform hydrologic modeling at basin-scale. This software allows a set of multisectoral water demands (domestic and industrial water supply, irrigation, hydropower generation, among others) and provides simulation and visualization in both space and time. We start by using the topography, soil type, soil use and vegetation cover of the region. Then the model is calibrated and tested, comparing model runoff estimates with observed data. Finally, the model is used to simulate the river basin catchment behavior to the typical conditions of the hydrological extreme events namely, heavy precipitation and drought. We present the geologic, hydrologic and climatologic characterization of the Corgo river catchment, list the most important factors that control the water availability in the river basin, describe the MIKE BASIN model calibration process, and discuss the role of each factor through sensibility tests and the estimated impacts of extreme events on the river basin management.

Pereira, M. G.; Carvalho, S.; Fernandes, L.; Caramelo, L.; Alencoão, A.

2012-04-01

244

Assessing agriculture–water links at the basin scale: hydrologic and economic models of the São Francisco River Basin, Brazil  

Microsoft Academic Search

This article uses a basin-wide hydrologic model to assess the hydrologic and economic effects of expanding agriculture in the São Francisco River Basin, Brazil. It then uses a basin-wide economic model of agriculture to examine the effects of implementing water use regulations. Preliminary results suggest that substantially expanding agriculture would put pressure on some of the river's environmental flows. Agricultural

Marco Maneta; Marcelo Torres; Stephen A. Vosti; Wesley W. Wallender; Summer Allen; Luís H. Bassoi; Lisa Bennett; Richard Howitt; Lineu Rodrigues; Julie Young

2009-01-01

245

Modelling long-term diffuse nitrate pollution at the catchment-scale: Data, parameter and epistemic uncertainty  

NASA Astrophysics Data System (ADS)

SummaryA model of catchment-scale nitrate transport is presented for a small, rural headwater basin (Alton Pancras: <10 km 2) in Dorset, UK, for the period 1930-2007. Estimates of annual nitrogen (N) loading were based on parish land-use data, held in the UK's National Archives, and previously reported figures of typical UK N loadings from livestock, fertiliser, ploughing of permanent pasture, atmospheric deposition, biological fixation and crop uptake. Loading calculations were performed within an uncertainty framework to allow for the reliance on literature data sources. Loading calculations show that all significant sources must be included not just fertiliser application which, at most, contributes 50% of N input in any given year. A simple algorithm was used to transform estimated catchment N loading (1930-2007) into a river nitrate response (observed data: 1980-2004). This assumed N-loads were delayed by some catchment mean travel time (MTT), t a, attenuated according to a Peclet number, P e, converted into solute concentrations by a factor, ?, to increase some initial baseline river concentration, C b. Simple graphical translation of estimated catchment N loading to the river concentration data suggested a MTT of around 37 years. As P e ? ?, the transport model simplified to a linear relationship between catchment N load and river nitrate concentration response lagged by the MTT. Hence, the model results suggest that, in this catchment, advection is the dominant mechanism for transport of diffuse pollution from land to river: there is little or no dispersion present. The MTT ( t a) was then reconsidered using an estimated distribution of unsaturated zone depths in the Alton Pancras catchment. Conclusions suggest that, in modelling of long-term nutrient transport, a detailed source term is of much greater importance than a complex hydrogeological model. Implications of epistemic uncertainty, long-term prediction and management of diffuse agricultural pollution are discussed.

Howden, N. J. K.; Burt, T. P.; Mathias, S. A.; Worrall, F.; Whelan, M. J.

2011-06-01

246

Controls on old and new water contributions to stream flow at some nested catchments in Vermont, USA  

USGS Publications Warehouse

Factors controlling the partitioning of old and new water contributions to stream flow were investigated for three events in four catchments (three of which were nested) at Sleepers River Research Watershed in Danville, Vermont. In the 1993 snowmelt period, two-component isotopic hydrograph separations showed that new water (meltwater) inputs to the stream ranged widely from 41 to 74%, and increased with catchment size (41 to 11 125 ha) (with one exception) and with open land cover (0-73%). Peak dissolved organic carbon concentrations and relative alkalinity dilution in stream water ranked in the same order among catchments as the new water fractions, suggesting that new water followed shallow flow paths. During the 1994 snowmelt, despite similar timing and magnitude of melt inputs, the new-water contribution to stream flow ranged only from 30 to 36% in the four catchments. We conclude that the uncommonly high and variable new water fractions in streamwater during the 1993 melt were caused by direct runoff of meltwater over frozen ground, which was prevalent in open land areas during the 1993 winter. In a high-intensity summer rainstorm in 1993, new water fractions were smaller relative to the 1993 snowmelt, ranging from 28 to 46%, but they ranked in the identical catchment order. Reconciliation of the contrasting patterns of new-old water partitioning in the three events appears to require an explanation that invokes multiple processes and effects, including: 1 topographically controlled increase in surface-saturated area with increasing catchment size; 2 direct runoff over frozen ground; 3 low infiltration in agriculturally compacted soils; 4 differences in soil transmissivity, which may be more relevant under dry antecedent conditions. These data highlight some of the difficulties faced by catchment hydrologists in formulating a theory of runoff generation at varying basin scales. Copyright ?? 2002 John Wiley and Sons, Ltd.

Shanley, J.B.; Kendall, C.; Smith, T.E.; Wolock, D.M.; McDonnell, J.J.

2002-01-01

247

Hydrologic sensitivities of the Sacramento-San Joaquin River basin, California, to global warming  

Microsoft Academic Search

The hydrologic sensitivities of four medium-sized mountainous catchments in the Sacramento and San Joaquin River basins to long-term global warming were analyzed. The hydrologic response of these catchments, all of which are dominated by spring snowmelt runoff, were simulated by the coupling of the snowmelt and the soil moisture accounting models of the U.S. National Weather Service River Forecast System.

D. P. Lettenmaier; Thian Yew Gan

1990-01-01

248

Estimating gully erosion contribution to large catchment sediment yield rate in Tanzania  

NASA Astrophysics Data System (ADS)

The objective of this paper is to report on the issues and proposed approaches in estimating the contribution of gully erosion to sediment yield at large catchment. The case study is the upstream of Pangani River Basin (PRB) located in the North Eastern part of Tanzania. Little has been done by other researchers to study and/or extrapolate gully erosion results from plot or field scale to large catchment. In this study multi-temporal aerial photos at selected sampling sites were used to estimate gully size and morphology changes over time. The laboratory aerial photo interpretation results were groundtruthed. A data mining tool, Cubist, was used to develop predictive gully density stepwise regression models using aerial photos and environment variables. The delivery ratio was applied to estimate the sediment yield rate. The spatial variations of gully density were mapped under Arc View GIS Environment. Gully erosion sediment yield contribution was estimated as a ratio between gully erosion sediment yield and total sediment yield at the catchment outlet. The general observation is that gullies are localized features and not continuous spatially and mostly located on some mountains’ foot slopes. The estimated sediment yield rate from gullies erosion is 6800 t/year, which is about 1.6% of the long-term total catchment sediment yield rate. The result is comparable to other study findings in the same catchment. In order to improve the result larger scale aerial photos and high resolution spatial data on soil-textural class and saturated hydraulic conductivity - are recommended.

Ndomba, Preksedis Marco; Mtalo, Felix; Killingtveit, Aanund

249

Sound management of sediment yields at the catchment scale by small detention ponds  

NASA Astrophysics Data System (ADS)

Keywords: small detention pond, sediment deposits, reservoir silting, urban catchment Globally observed land use and climate changes have a clear impact on the sediment yields deriving from the catchment. Released sediments may originate from different point and non-point sources. Thereby it is difficult to manage and reduce sediment loads directly at the source without undertaking detailed and expensive monitoring programs. Small detention ponds are therefore frequently used water management systems in urban settlements to improve water quality at the catchment scale. Such ponds located at the outlet of small basins allow reducing sediment loads downstream. Additionally, they capture sediment-associated contaminants as heavy metals, nutrients and micropollutants. On the other hand, a sedimentation within the pond may be a severe problem because it decreases over the time its retention capacity. This is especially significant for small detention ponds, where the siltation rate is high. These ponds can loose their total capacity already after few years of their exploitation when no dredging operations are considered. Unfortunately, maintenance costs of small ponds are expensive and usually not taken into account when planning and constructing such ponds. Consequently, many small detention ponds become inefficient after an entire use of their capacity. Therefore careful planning of maintenance options is essential to keep an effectiveness of such ponds on the expected level. Within presented here study we addressed the problem of silting small detention ponds and we assessed an applicability of such ponds to manage sediment yields discharged from small urban catchments. To this end, a periodic measurement of deposited sediments within a small detention pond (1.35 ha, 5 years old, Warsaw, Poland) has been undertaken. This pond receives a polluted runoff from a small urbanized basin (30 km2), for which no routine sediment measurement exists. The spatial sediment thickness within the pond was measured twice (in 2009 and 2011) by the echo sounding technique. A resulting sediment deposit volume was computed by constructing a Digital Elevation Model (DEM) of the pond. An alternating reservoir volume was estimated for both measurements and confronted with the initial characteristics (2007). Our first results demonstrate that the pond will loose its sufficient capacity after about ten years if no regular sediment dredging is undertaken. Moreover, the useful time of the pond will decrease by two years when the catchment area increases by 10% due to expected urbanization. Furthermore, different scenarios of maintenance options were analyzed and recommendations for sound sediment management of similar small ponds in urban catchments were given.

Sikorska, A. E.; Wasilewicz, M.; Banasik, K.

2012-04-01

250

Understanding Polycyclic Aromatic Hydrocarbon transfers at the catchment scale combining chemical and fallout radionuclides analyses  

NASA Astrophysics Data System (ADS)

Contamination of river water and sediment constitutes a major environmental issue for industrialized countries. Polycyclic Aromatic Hydrocarbons (PAHs) are a group of persistent organic pollutants characterized by two or more fused rings. In recent years, studies dealing with PAHs have grown in number. Some PAHs present indeed a high risk for environment and human health because of their carcinogenic and mutagenic properties. However, most of these studies focused on measuring PAH concentration in the different compartments of the environment (air, soil, sediment, water, etc.) In this context, there remains a lack of understanding regarding the various processes responsible for PAH transfers from one environmental compartment to another. Our study aims to quantify PAHs transfers at the catchment scale by combining chemical analysis with gamma spectrometry. Air, soil, river water and sediment samples (n=820) were collected in two upstream sub-catchments of the Seine River basin (France) during one year. Chemical analyses were carried out to determine PAHs concentrations in all samples. Furthermore, measurement of fallout radionuclides (Beryllium-7, Lead-210, Caesium-137) in both rainfall and river sediment provided a way to discriminate between freshly eroded sediment vs. resuspension of older material that previously deposited on the riverbed. This information is crucial to estimate PAH residence time and transfer velocities in the Seine River basin. The results show that the PAH behaviour varies from one subcatchment to the next. PAH transfers depend indeed on both the characteristics of the catchment (e.g. topography, presence of drained cropland in catchments) and the local anthropogenic pressures. A significant increase in atmospheric deposition of PAHs is observed during winter due to a larger number of sources (household heating). The 14-month study has also highlighted the seasonal variations of PAH fluxes, which are mainly related to the hydrological regimes (i.e. low flow vs. flood periods). The behaviour of the PAHs mainly depends on their molecular mass. The lightest ones tend to quickly migrate to rivers whereas the heaviest slowly accumulate in soils throughout the low-flow period. Then, an increase in PAH export associated with sediment is observed during the winter floods, when rivers are heavily loaded with suspended matter. The downstream exports of PAHs are controlled by the main erosion processes that occurred in the catchments. Results show that PAH fluxes are more important when material is mostly supplied to rivers by soil surface erosion processes than when they are delivered by gully or riverbank erosion. Despite the reduction in PAH emissions since the 1960s, there is still a significant storage of PAHs in the upstream part of the Seine River basin. In this context, WFD objectives are unlikely to be reached by 2015.

Gateuille, David; Evrard, Olivier; Lefevre, Irène; Moreau-Guigon, Elodie; Alliot, fabrice; Chevreuil, Marc; Mouchel, Jean-Marie

2013-04-01

251

Before and after integrated catchment management in a headwater catchment: changes in water quality.  

PubMed

Few studies have comprehensively measured the effect on water quality of catchment rehabilitation measures in comparison with baseline conditions. Here we have analyzed water clarity and nutrient concentrations and loads for a 13-year period in a headwater catchment within the western Waikato region, New Zealand. For the first 6 years, the entire catchment was used for hill-country cattle and sheep grazing. An integrated catchment management plan was implemented whereby cattle were excluded from riparian areas, the most degraded land was planted in Pinus radiata, channel banks were planted with poplar trees and the beef cattle enterprise was modified. The removal of cattle from riparian areas without additional riparian planting had a positive and rapid effect on stream water clarity. In contrast, the water clarity decreased in those sub-catchments where livestock was excluded but riparian areas were planted with trees and shrubs. We attribute the decrease in water clarity to a reduction in groundcover vegetation that armors stream banks against preparatory erosion processes. Increases in concentrations of forms of P and N were recorded. These increases were attributed to: (i) the reduction of instream nutrient uptake by macrophytes and periphyton due to increased riparian shading; (ii) uncontrolled growth of a nitrogen fixing weed (gorse) in some parts of the catchment, and (iii) the reduction in the nutrient attenuation capacity of seepage wetlands due to the decrease in their areal coverage in response to afforestation. Our findings highlight the complex nature of the water quality response to catchment rehabilitation measures. PMID:25228091

Hughes, Andrew O; Quinn, John M

2014-12-01

252

Volume-Duration-Frequencies for Ungaged Catchments in Texas  

E-print Network

This report summarizes results from studies to determine relationships among the volume, duration and frequencies of floods in ungaged catchments in Texas. Methodologies were adopted for determining flood volumes at unregulated, non-urban catchments...

Devulapalli, Ravi S.; Valdes, Juan B.

253

Medium to long-term impacts of forest fires on slope to catchment-scale processes under current and future climate  

NASA Astrophysics Data System (ADS)

Forest wildfires can have important impacts on hydrological and soil erosion processes in burnt areas due to a variety of changes to soil properties and vegetation cover. The relevance of these impacts varies with wildfire characteristics, post-fire rainfall regime, and pre- and post-fire land management. The complex interactions between the various factors and processes have been one of the major obstacles to assessing wildfire impacts, particularly at larger spatial scales and over medium to long-term periods. This presentation will show ongoing research on a forested region in north-central Portugal, the Vouga river basin, aiming at: (i) quantifying medium and long-term impacts of wildfires, and (ii) estimating the impacts of climate change on wildfire regimes and assess their implications in terms of hydrological and soil erosion processes, and land degradation in general. The focus will be in the methodology and some preliminary results. To quantify medium and long-term impacts, existing information and data on the hydrological and soil erosion impacts of forest fires at small spatial and temporal scales has been compiled and analyzed. This information is the product of various international and national projects occurring since 1992, consisting of numerous observations on hydrological and erosion processes at the plot and hillslope. Ongoing work is also focusing on collecting data at the micro-catchment scale, and remote sensing imagery is being explored as a complementary information source, especially for large-scale landcover recovery patterns. The ultimate goal is to up-scale this information to meso and regional-scale catchments (100-250 km2) as well as to decade and longer periods. A simple modeling tool is being developed for impact assessment across spatial scales, addressing both on-site effects such as land degradation, and off-site effects such as flood risks and sediment export rates. Preliminary results for a slope-scale application of the model will be presented. The above-mentioned modeling tool, combined with climate change scenarios, will afterwards be used to estimate changes to wildfire regimes (frequency and intensity), and to assess their implications in terms of hydrological and soil erosion processes, and land degradation in general.

Nunes, João. Pedro; Alves Coelho, Celeste; Keizer, Jan Jacob

2010-05-01

254

Coupling a basin erosion and river sediment transport model into a large scale hydrological model: an application in the Amazon basin  

NASA Astrophysics Data System (ADS)

This study presents the first application and preliminary results of the large scale hydrodynamic/hydrological model MGB-IPH with a new module to predict the spatial distribution of the basin erosion and river sediment transport in a daily time step. The MGB-IPH is a large-scale, distributed and process based hydrological model that uses a catchment based discretization and the Hydrological Response Units (HRU) approach. It uses physical based equations to simulate the hydrological processes, such as the Penman Monteith model for evapotranspiration, and uses the Muskingum Cunge approach and a full 1D hydrodynamic model for river routing; including backwater effects and seasonal flooding. The sediment module of the MGB-IPH model is divided into two components: 1) prediction of erosion over the basin and sediment yield to river network; 2) sediment transport along the river channels. Both MGB-IPH and the sediment module use GIS tools to display relevant maps and to extract parameters from SRTM DEM (a 15" resolution was adopted). Using the catchment discretization the sediment module applies the Modified Universal Soil Loss Equation to predict soil loss from each HRU considering three sediment classes defined according to the soil texture: sand, silt and clay. The effects of topography on soil erosion are estimated by a two-dimensional slope length (LS) factor which using the contributing area approach and a local slope steepness (S), both estimated for each DEM pixel using GIS algorithms. The amount of sediment releasing to the catchment river reach in each day is calculated using a linear reservoir. Once the sediment reaches the river they are transported into the river channel using an advection equation for silt and clay and a sediment continuity equation for sand. A sediment balance based on the Yang sediment transport capacity, allowing to compute the amount of erosion and deposition along the rivers, is performed for sand particles as bed load, whilst no erosion or deposition is allowed for silt and clay. The model was first applied on the Madeira River basin, one of the major tributaries of the Amazon River (~1.4*106 km2) accounting for 35% of the suspended sediment amount annually transported for the Amazon river to the ocean. Model results agree with observed data, mainly for monthly and annual time scales. The spatial distribution of soil erosion within the basin showed a large amount of sediment being delivered from the Andean regions of Bolivia and Peru. Spatial distribution of mean annual sediment along the river showed that Madre de Dios, Mamoré and Beni rivers transport the major amount of sediment. Simulated daily suspended solid discharge agree with observed data. The model is able to provide temporaly and spatialy distributed estimates of soil loss source over the basin, locations with tendency for erosion or deposition along the rivers, and to reproduce long term sediment yield at several locations. Despite model results are encouraging, further effort is needed to validate the model considering the scarcity of data at large scale.

Buarque, D. C.; Collischonn, W.; Paiva, R. C. D.

2012-04-01

255

Catchment scale multi-objective flood management  

NASA Astrophysics Data System (ADS)

Rural land management is known to affect both the generation and propagation of flooding at the local scale, but there is still a general lack of good evidence that this impact is still significant at the larger catchment scale given the complexity of physical interactions and climatic variability taking place at this level. The National Trust, in partnership with the Environment Agency, are managing an innovative project on the Holnicote Estate in south west England to demonstrate the benefits of using good rural land management practices to reduce flood risk at the both the catchment and sub-catchment scales. The Holnicote Estate is owned by the National Trust and comprises about 5,000 hectares of land, from the uplands of Exmoor to the sea, incorporating most of the catchments of the river Horner and Aller Water. There are nearly 100 houses across three villages that are at risk from flooding which could potentially benefit from changes in land management practices in the surrounding catchment providing a more sustainable flood attenuation function. In addition to the contribution being made to flood risk management there are a range of other ecosystems services that will be enhanced through these targeted land management changes. Alterations in land management will create new opportunities for wildlife and habitats and help to improve the local surface water quality. Such improvements will not only create additional wildlife resources locally but also serve the landscape response to climate change effects by creating and enhancing wildlife networks within the region. Land management changes will also restore and sustain landscape heritage resources and provide opportunities for amenity, recreation and tourism. The project delivery team is working with the National Trust from source to sea across the entire Holnicote Estate, to identify and subsequently implement suitable land management techniques to manage local flood risk within the catchments. These techniques will include: controlling headwater drainage, increasing evapotranspiration and interception by creating new woodlands in the upper catchment areas, enabling coarse woody debris dams to slow down water flows through steep valleys, improving soil water storage potential by appropriate soil and crop management, retaining water on lowland flood meadows and wet woodland creation within the floodplain. The project, due to run from 2009 until 2013, incorporates hydrometric and water quality monitoring, together with hydrologic and hydraulic modelling in order to attempt to demonstrate the effect of land management changes on flood dynamics and flood risk management. To date, the project team have undertaken the fundamental catchment characterisation work to understand its physical setting and the interaction of the physical processes that influence the hydrological response of the catchment to incident precipitation. The results of this initial work has led to the identification of a suitably robust hydrometric monitoring network within the catchments to meet the needs of providing both quantitative evidence of the impacts of land management change on flood risk, together with generating good quality datasets for the validation and testing of the new hydrologic models. As the project aims to demonstrate ‘best practice' in all areas, the opportunity has been taken to install a network of automatic hydrometric monitoring equipment, together with an associated telemetry system, in order to maximise data coverage, accuracy and reliability. Good quality datasets are a critical requirement for reliable modelling. The modelling will also be expanded to incorporate climate change scenarios. This paper will describe the catchment characterisation work undertaken to date, the proposed land management changes in relation to flood risk management, the initial catchment hydraulic modelling work and the implementation of the new hydrometric monitoring network within the study area.

Rose, Steve; Worrall, Peter; Rosolova, Zdenka; Hammond, Gene

2010-05-01

256

Nitrogen and Carbon Cycling in Deforested and Pristine Upland (2400m) Forest Catchments in the Peruvian Andes  

NASA Astrophysics Data System (ADS)

Nitrogen and carbon cycling were examined within two upland (2400m) forest catchments in the Peruvian Andes. One catchment was partially deforested within the last 3 years, while the other has remained untouched. Tracer amended samples were analyzed to determine the pathways and rates of nitrogen cycling in streams draining each catchment. Both streams exhibited very low inorganic nitrogen levels, on the order of 1 to 2 uM. A large percentage (>1/3) of the total fixed nitrogen flux from these systems was in the form of particulates. Preliminary results suggest a very high rate of nitrogen cycling in these systems. Isotopic measurements of plant samples from both catchments also suggest that these forests are highly efficient in trapping and using atmospheric nitrogen sources. The partially deforested catchment had significantly more species using C4 and CAM carbon fixation pathways. Leaf litter from both streams and leaves from trees in the area were also analyzed for carbon and nitrogen isotopes to compare and contrast nitrogen and carbon cycling between the two sites. This and other data to be presented suggest that deforestation has subtle but significant effects upon the ability of tropical upland forests to retain and use nutrients.

Townsend-Small, A.; Haberer, J.; McClain, M.; Ramos, O.; Gardner, W.; McCarthy, M.; Brandes, J.

2001-12-01

257

Towards the determination of an optimal scale for stormwater quality management: micropollutants in a small residential catchment.  

PubMed

Stormwater and atmospheric deposits were collected on a small residential urban catchment (0.8 ha) near Paris in order to determine the levels of certain micropollutants (using a preliminary scan of 69 contaminants, followed by a more detailed quantification of PAHs, PCBs, alkylphenols and metals). Atmospheric inputs accounted for only 10%-38% of the stormwater contamination (except for PCBs), thus indicating substantial release within the catchment. On this small upstream catchment however, stormwater contamination is significantly lower than that observed downstream in storm sewers on larger adjacent urban catchments with similar land uses. These results likely stem from cross-contamination activity during transfers inside the sewer system and underscore the advantages of runoff management strategies at the source for controlling stormwater pollutant loads. Moreover, it has been shown that both contamination levels and contaminant speciation evolve with the scale of the catchment, in correlation with a large fraction of dissolved contaminants in upstream runoff, which differs from what has been traditionally assumed for stormwater. Consequently, the choice of treatment device/protocol must be adapted to the management scale as well as to the targeted type of contaminant. PMID:22204938

Bressy, A; Gromaire, M-C; Lorgeoux, C; Saad, M; Leroy, F; Chebbo, G

2012-12-15

258

Human impacts on river water quality- comparative research in the catchment areas of the Tone River and the Mur River-  

NASA Astrophysics Data System (ADS)

Human activities in river basin affect river water quality as water discharges into river with pollutant after we use it. By detecting pollutants source, pathway, and influential factor of human activities, it will be possible to consider proper river basin management. In this study, material flow analysis was done first and then nutrient emission modeling by MONERIS was conducted. So as to clarify land use contribution and climate condition, comparison of Japanese and European river basin area has been made. The model MONERIS (MOdelling Nutrient Emissions in RIver Systems; Behrendt et al., 2000) was applied to estimate the nutrient emissions in the Danube river basin by point sources and various diffuse pathways. Work for the Mur River Basin in Austria was already carried out by the Institute of Water Quality, Resources and Waste Management at the Vienna University of Technology. This study treats data collection, modelling for the Tone River in Japan, and comparative analysis for these two river basins. The estimation of the nutrient emissions was carried out for 11 different sub catchment areas covering the Tone River Basin for the time period 2000 to 2006. TN emissions into the Tone river basin were 51 kt/y. 67% was via ground water and dominant for all sub catchments. Urban area was also important emission pathway. Human effect is observed in urban structure and agricultural activity. Water supply and sewer system make urban water cycle with pipeline structure. Excess evapotranspiration in arable land is also influential in water cycle. As share of arable land is 37% and there provides agricultural products, it is thought that N emission from agricultural activity is main pollution source. Assumption case of 10% N surplus was simulated and the result was 99% identical to the actual. Even though N surplus reduction does not show drastic impact on N emission, it is of importance to reduce excess of fertilization and to encourage effective agricultural activity. Population rate of waste water treatment is 67 % in the total catchment area. Assumption case of 100% WWT was simulated and the result suggests that connection to public sewer system with WWTP is effective potential measure. TN emission in the Tone is higher than it in the Mur. Emission per capita is almost same level for both basin areas. Though the personal pollution stresses same as European basin area, the basin has huge population and activities to support their daily life. Agricultural activity and urban structure have great impacts on N emission and on the river water quality. Possible remedy for river pollution is construction of sewer system with waste water treatment. Agricultural activity is potential betterment factor. Comparison of Mur, Tone and assumption cases

Kogure, K.

2013-12-01

259

Temporal variation in sediment budget components for a small incised upland catchment in southeastern Australia  

NASA Astrophysics Data System (ADS)

Temporal variation in process rates, sediment storage and exports can result in substantial changes to components of catchment sediment budgets over both short and long timescales. Quantifying the magnitude of temporal change in sediment budgets is important for interpretation of current and future processes and in understanding landform change. In this study, we develop a fine (900 m) plateau, with channel incision extending along the valley floor to mid-catchment. Land use is predominantly sheep and cattle grazing of pasture, with unrestricted stock access to channels. Various process-based techniques were used to examine temporal variation in sediment budget components over seasonal timescales (3-4 monthly) for a period of nearly two years. This included monitoring of hillslope and channel bank erosion, channel cross-sectional change, and suspended sediment output in conjunction with USLE-based hillslope erosion modelling and sediment source tracing using 137Cs and 210Pbex. Over the total study period, the sediment budget developed from these datasets indicated channel bank erosion accounted for an estimated 80% (41.6 t) of total sediment inputs. Valley floor and in-channel sediment storage represented 53% of total inputs and the remaining 47% was exported from the catchment. Temporal variation in catchment suspended sediment exports was largely dependent on the dynamics of sediment supply and storage within eroding channels. This was reflected in the sediment delivery ratios (SDR) for individual measurement intervals, which ranged from 1 to 153%. Bank sediment supply during low rainfall periods was reduced but subaerial processes - including rainsplash and sheetwash, freeze-thaw, and stock trampling effects - continued delivering sediment to channels, resulting in net accumulation on the channel bed with insufficient flow to transport this material to the catchment outlet. Following the higher flow period in spring of the first year of monitoring, sediment supplied to channels during the 3-month measurement interval was removed as well as an estimated 72% of the sediment accumulated on the channel bed since the start of the study period. The variation in rainfall patterns, pasture vegetation growth, and antecedent soil moisture with seasons and drought conditions contributed to observed hydrological response and sediment flux patterns. Given the seasonal and drought-dependent variability in sediment storage and delivery, the period of monitoring may have an important influence on the overall SDR and interpretation of sediment transfer through catchments. This study also highlighted the potential significance of sediment dynamics in channels for determining contemporary sediment yields from small gullied upland catchments in southeastern Australia, which are widespread in parts of the southern Murray-Darling Basin and appear to represent an important source of fine sediment delivered to lowlands.

Smith, Hugh; Dragovich, Deirdre

2010-05-01

260

Hydrological improvements for nutrient and pollutant emission modeling in large scale catchments  

NASA Astrophysics Data System (ADS)

An estimation of emissions and loads of nutrients and pollutants into European water bodies with as much accuracy as possible depends largely on the knowledge about the spatially and temporally distributed hydrological runoff patterns. An improved hydrological water balance model for the pollutant emission model MoRE (Modeling of Regionalized Emissions) (IWG, 2011) has been introduced, that can form an adequate basis to simulate discharge in a hydrologically differentiated, land-use based way to subsequently provide the required distributed discharge components. First of all the hydrological model had to comply both with requirements of space and time in order to calculate sufficiently precise the water balance on the catchment scale spatially distributed in sub-catchments and with a higher temporal resolution. Aiming to reproduce seasonal dynamics and the characteristic hydrological regimes of river catchments a daily (instead of a yearly) time increment was applied allowing for a more process oriented simulation of discharge dynamics, volume and therefore water balance. The enhancement of the hydrological model became also necessary to potentially account for the hydrological functioning of catchments in regard to scenarios of e.g. a changing climate or alterations of land use. As a deterministic, partly physically based, conceptual hydrological watershed and water balance model the Precipitation Runoff Modeling System (PRMS) (USGS, 2009) was selected to improve the hydrological input for MoRE. In PRMS the spatial discretization is implemented with sub-catchments and so called hydrologic response units (HRUs) which are the hydrotropic, distributed, finite modeling entities each having a homogeneous runoff reaction due to hydro-meteorological events. Spatial structures and heterogeneities in sub-catchments e.g. urbanity, land use and soil types were identified to derive hydrological similarities and classify in different urban and rural HRUs. In this way the hydrological system is simulated spatially differentiated and emissions from urban and rural areas into river courses can be detected separately. In the Ruhr catchment (4.485 km2) as a right tributary of the Rhine located in the lower mountain range of North Rhine-Westphalia in Germany for the validation period 2002-2006 the hydrological model showed first satisfying results. The feasibility study in the Ruhr shows the suitability of the approach and illustrates the potentials for further developments in terms of an implementation throughout the German and contiguous watersheds. IWG, Karlsruhe Institute of Technology (KIT). 2011. http://isww.iwg.kit.edu/MoRE.php. [Online] Institute for Water and River Basin Management, Department of Aquatic Environmental Engineering, October 2011. USGS, U.S. Geological Survey. 2009. PRMS-2009, the Precipitation-Runoff Modeling System. Denver, Colorado : s.n., 2009. Bd. U.S. Geologic Survey Open File Report.

Höllering, S.; Ihringer, J.

2012-04-01

261

Identification of internal flow dynamics in two experimental catchments  

USGS Publications Warehouse

Identification of the internal flow dynamics in catchments is difficult because of the lack of information in precipitation -stream discharge time series alone. Two experimental catchments, Hydrohill and Nandadish, near Nanjing in China, have been set up to monitor internal flows reaching the catchment stream at various depths, from the surface runoff to the bedrock. With analysis of the precipitation against these internal discharges, it is possible to quantify the time constants and volumes associated with various flowpaths in both catchments.

Hansen, D.P.; Jakeman, A.J.; Kendall, C.; Weizu, G.

1997-01-01

262

Hydrological Ensemble Simulation in Huaihe Catchment Based on VIC Model  

NASA Astrophysics Data System (ADS)

Huaihe catchment plays a very important role in the political, economic, and cultural development in China. However, hydrological disasters frequently occur in Huaihe catchment, and thus hydrological simulation in this area has very important significance. The Variable Infiltration Capacity(VIC)model, a macroscale distributed hydrological model is applied to the upper Huaihe Catchment, to simulate the discharge of the basin outlet Bengbu station from 1970 to 1999. The uncertainty in the calibration of VIC model parameters has been analyzed, and the best set of parameters in the training period of 1970~1993 is achieved using the Generalized Likelihood Uncertainty Estimation (GLUE) method. The study also addresses the influence of different likelihood functions for the parameter sensitivity as well as the uncertainty of discharge simulation. Results show that among the six chosen parameters, the soil thickness of the second layer (d2) is the most sensitive one, followed by the saturation capacity curve shape parameter (B). Moreover, the parameter selection is sensitive to different likelihood functions. For example, the soil thickness of the third layer (d3) is sensitive when using Nash coefficient as the likelihood function, while d3 is not sensitive when using relative error as the likelihood function. With the 95% confidence interval, the coverage rate of the simulated discharge versus the observed discharge is small (around 0.4), indicating that the uncertainty in the model is large. The coverage rate of selecting relative error as the likelihood function is bigger than that of selecting Nash coefficient. Based on the calibration and sensitivity studies, hydrological ensemble forecasts have been established using multiple parameter sets. The ensemble mean forecasts show better simulations than the control forecast (i.e. the simulation using the best set of parameters) for the long-term trend of discharge, while the control forecast is better in the simulation of peak value. Probabilistic streamflow forecasts are also evaluated in the simulation of extreme peak flow. In addition, the influence of different training periods for the parameter sensitivity is discussed. Parameter scatter diagrams Discharge of Bengbu station

Sun, R.; Yuan, H.

2013-12-01

263

Linked catchment and scenario analysis of nitrogen leaching and loading: a case-study from a Danish catchment-fjord system, Mariager Fjord  

NASA Astrophysics Data System (ADS)

An empirical modelling approach to quantify N-leaching, sub-surface N-removal and N-loading within the Danish Mariager Fjord catchment is presented. The integrated approach combines the use of river monitoring data, agricultural data from national databases and an empirical leaching model. In order to investigate different possibilities to reduce both N-leaching within the sub-catchments and total N-loading to the Mariager Fjord, the method has been applied for current agricultural and land use conditions as well as for three scenarios of changed agricultural practises and land use settings. For the scenario examples chosen, a reduction in application of fertilisers by 10% and 20%, respectively, combined with a demand for a 15% better utilisation efficiency of animal manure may lead to a 6% and 8% reduction in the nitrogen loading from the river basin to the fjord. A higher reduction could be facilitated if more than 10% of all agricultural areas would be afforested according to the existing regional plans for the river basin.

Müller-Wohlfeil, D.-I.; Jørgensen, J. O.; Kronvang, B.; Wiggers, L.

264

Creating a Geologic Play Book for Trenton-Black River Appalachian Basin Exploration  

Microsoft Academic Search

Preliminary isopach and facies maps, combined with a literature review, were used to develop a sequence of basin geometry, architecture and facies development during Cambrian and Ordovician time. The main architectural features--basins, sub basins and platforms--were identified and mapped as their positions shifted with time. This is significant because a better understanding of the control of basin geometry and architecture

Douglas G. Patchen; Taury Smith; Ron Riley; Mark Baranoski; David Harris; John Hickman; John Bocan; Michael Hohn

2005-01-01

265

Influence of Catchment Scale and Landscape Controls on Runoff Sources and Mean Residence Times in Montane Watersheds  

NASA Astrophysics Data System (ADS)

The influence of catchment scale and landscape controls on hydrological sources and mean residence times were assessed in nested sub-basins of 3 separate montane watersheds (30-230km2) in northern Scotland. Geochemical and isotopic tracers were used to carry out chemical hydrograph separations to quantify the relative contribution of different hydrological sources to annual runoff and estimate mean residence times in 24 individual catchments at scales ranging from 0.9km to 230km2. Mean annual groundwater contributions varied between 23 and 54% of annual runoff, and mean residence times varied between 83 days and 443 days. A GIS was used for watershed analysis to assess the relative importance of landscape controls on hydrological sources and residence times. Neither of these hydrological descriptors exhibited significant correlations with catchment scale. Both were influenced by various topographic indices (eg mean slope and flowpath length), but were most strongly related to catchment soil cover mapped using the UK HOST (Hydrology Of Soil Types) national digital data base. Soils could be sub-divided between more hydrologically "responsive" montane soils (eg peats, regosols, and gleysols), which generate storm runoff by overland flow and shallow subsurface storm flow and more "free-draining" soils (eg podsols and inceptisols) that facilitate groundwater recharge. For the 24 catchments, the percentage cover of "responsive soils" was negatively correlated with groundwater contributions to annual flows were (r2 0.58, p <0.0001) and mean residence times (r2 0.82, p<0.0001). The study shows that accurate digital soil maps can provide excellent insights into hydrological functioning in catchments at a range of scales in montane environments. Despite their significance in water resource management as river headwaters, such catchments are often remote and logistically difficult to instrument, particularly at large scales. As soils integrate the effects of heterogeneities in catchment topography, geology, climate and vegetation, the paper will stress that soil maps have considerable potential for rapid impact assessment and modelling studies in ungauged basins in montane areas.

Soulsby, C.; Tetzlaff, D.; Waldron, S.; Dunn, S.

2005-12-01

266

Internal Catchment Data for Improved Model Diagnosis and Calibration  

Microsoft Academic Search

There have been numerous calls for the need to incorporate internal catchment observations for improving distributed catchment models. Recent results from a synthetic study by van Werkhoven et al., (GRL, 2008) imply that the relative worth of internal catchment observations for providing information to improve downstream predictions is limited to a time-varying zone, or cone of influence - that is,

D. C. Goodrich; M. Srinivasan; H. McMillan; M. Duncan; S. Yatheendradas; T. Wagener; M. Clark; G. Martinez; H. Gupta; B. Jackson; J. Schmidt; R. Woods

2008-01-01

267

Forest Research Dyfi Catchment and Woodland Research Platform  

E-print Network

Forest Research Dyfi Catchment and Woodland Research Platform The Dyfi Catchment and Woodland and tourism. The Dyfi Catchment and Woodland Research Platform is data-rich. Both existing and new data Richard Lucas. Forest Research Forest Research is the research agency of the Forestry Commission

268

Modeling daily streamflow at ungauged catchments: What information is necessary?  

NASA Astrophysics Data System (ADS)

Streamflow modeling at ungauged catchments involves transfer of information (viz., model structure and parameters) from gauged to ungauged catchments that are judged to be hydrologically similar. In this study, we focus on identifying: (1) what constitutes the critical information that needs to be transferred among hydrologically similar catchments to achieve good predictability using models at ungauged sites, and (2) which is the best approach for transferring this information from gauged to ungauged catchments. We develop a simple hydrologic model with minimal calibration requirement and implement it over 756 catchments located across the continental United States. The model computes water balance at a daily time-step and conceptualizes subsurface runoff through a storage-dependent exponential decline in saturated hydraulic conductivity. Snow accumulation and melt are modeled using the thermal degree-day concept. The calibrated model performs better in humid runoff-dominated regions than in the drier evapotranspiration-dominated regions. Results show that within a region, transfer of hydrograph recession information alone is sufficient for reliable streamflow predictions at ungauged catchments. Information transfer from spatially proximate gauged catchments provides better streamflow predictability at ungauged catchments than transfer from catchments identified as physically similar. When considering spatially proximate catchments, information transfer from multiple donor catchments is preferable to transfer from a single donor catchment.

Patil, S.; Stieglitz, M.

2011-12-01

269

Evaluating the critical source area concept of phosphorus loss from soils to water-bodies in agricultural catchments.  

PubMed

Using data collected from six basins located across two hydrologically contrasting agricultural catchments, this study investigated whether transport metrics alone provide better estimates of storm phosphorus (P) loss from basins than critical source area (CSA) metrics which combine source factors as well. Concentrations and loads of P in quickflow (QF) were measured at basin outlets during four storm events and were compared with dynamic (QF magnitude) and static (extent of highly-connected, poorly-drained soils) transport metrics and a CSA metric (extent of highly-connected, poorly-drained soils with excess plant-available P). Pairwise comparisons between basins with similar CSA risks but contrasting QF magnitudes showed that QF flow-weighted mean TRP (total molybdate-reactive P) concentrations and loads were frequently (at least 11 of 14 comparisons) more than 40% higher in basins with the highest QF magnitudes. Furthermore, static transport metrics reliably discerned relative QF magnitudes between these basins. However, particulate P (PP) concentrations were often (6 of 14 comparisons) higher in basins with the lowest QF magnitudes, most likely due to soil-management activities (e.g. ploughing), in these predominantly arable basins at these times. Pairwise comparisons between basins with contrasting CSA risks and similar QF magnitudes showed that TRP and PP concentrations and loads did not reflect trends in CSA risk or QF magnitude. Static transport metrics did not discern relative QF magnitudes between these basins. In basins with contrasting transport risks, storm TRP concentrations and loads were well differentiated by dynamic or static transport metrics alone, regardless of differences in soil P. In basins with similar transport risks, dynamic transport metrics and P source information additional to soil P may be required to predict relative storm TRP concentrations and loads. Regardless of differences in transport risk, information on land use and management, may be required to predict relative differences in storm PP concentrations between these agricultural basins. PMID:24863139

Shore, M; Jordan, P; Mellander, P-E; Kelly-Quinn, M; Wall, D P; Murphy, P N C; Melland, A R

2014-08-15

270

Seasonal variability of suspended sediment transport in the Seine river catchment area (France)  

NASA Astrophysics Data System (ADS)

This study consists in an innovative application of environmental physico-chemical techniques on fluvial sediments with the aim to trace the seasonal changes in suspended sediment transport of the complex Seine river catchment area in northern France. The aim of this project is to develop a detailed understanding for the discrimination of naturally triggered and anthropogenic induced processes and their temporal changes with weather conditions. With a focus on the heavy metal fraction, we determine the regional distribution of the suspended material and search for environmental fingerprints demonstrating the influence of fluvial transport mechanisms, changes in concentration related to discharge variations or different sediment sources, and in-situ alteration caused by variations in the geochemical conditions (oxy-redox, pH, Eh, etc.). To achieve these goals, we apply a combination of straightforward rock magnetic hysteresis measurements (performed using an AGM2900 at the LSCE) and advanced scanning electron microscopy analyses (SEM). This interdisciplinary approach allows refining the detailed analysis of sediment trap samples, originating from Tessier et al. (2003), as recently shown by Franke et al. (2009). In our preliminary results, we observe a general increase in magnetic concentrations from summer to winter conditions, coupled with a magneto-mineralogic change to rather reduced metallic mineral phases. However, each riversection of the Seine system shows its specific trend line depending on the regional initial input, weathering conditions, drainage area and potential pollution sources. A systematic analysis of the detailed results will allow highlighting the climatic/seasonal influence on the metallic particle assembly. Keywords: Seine river system, environmental magnetism, suspended particulate matter, anthropogenic and natural input, magnetic hysteresis, scanning electron microscopy (SEM),, heavy metal pollution, seasonal variability References: Franke, C., Kissel, C., Robin, E., Bonté, P. and Lagroix, F., 2009, Magnetic particle characterization in the Seine river system: Implications for the determination of natural versus anthropogenic input, Geochem. Geophys. Geosyst., doi:10.1029/2009GC002544. Tessier, L., Bonté, P., Mouchel, J.M., Lefevre, I., Sogon, S., Ayrault, S., Le Cloarec, M.F., 2003, Transport et characterisation des matieres en suspension dans le basin de la Seine : Identification des signatures naturelles et anthropiques, 14èmes Journées Scientifiques de l'Environnement : l'Eau, la Ville, la Vie, Créteil : France 2003. http://hal.archives-ouvertes.fr/docs/00/20/30/84/PDF/4-JSE-2003-Manuscrit-Tessier-HAL-2008-01-08.pdf

Franke, Christine; Baati, Selma; Ayrault, Sophie; Bonte, Philippe; Evrard, Olivier; Kissel, Catherine

2010-05-01

271

Comparative assessment of predictions in ungauged basins - Part 2: Flood and low flow studies  

NASA Astrophysics Data System (ADS)

The objective of this paper is to assess the performance of methods that predict low flows and flood runoff in ungauged catchments. The aim is to learn from the similarities and differences between catchments in different places, and to interpret the differences in performance in terms of the underlying climate-landscape controls. The assessment is performed at two levels. The Level 1 assessment is a meta-analysis of 14 low flow prediction studies reported in the literature involving 3112 catchments, and 20 flood prediction studies involving 3023 catchments. The Level 2 assessment consists of a more focused and detailed analysis of individual basins from selected studies from Level 1 in terms of how the leave-one-out cross-validation performance depends on climate and catchment characteristics as well as on the regionalisation method. The results indicate that both flood and low flow predictions in ungauged catchments tend to be less accurate in arid than in humid climates and more accurate in large than in small catchments. There is also a tendency towards a somewhat lower performance of regressions than other methods in those studies that apply different methods in the same region, while geostatistical methods tend to perform better than other methods. Of the various flood regionalisation approaches, index methods show significantly lower performance in arid catchments than regression methods or geostatistical methods. For low flow regionalisation, regional regressions are generally better than global regressions.

Salinas, J. L.; Laaha, G.; Rogger, M.; Parajka, J.; Viglione, A.; Sivapalan, M.; Blöschl, G.

2013-07-01

272

Floods and low flows prediction in ungauged basins - a comparative assessment of studies  

NASA Astrophysics Data System (ADS)

The objective of this study is to assess the performance of methods that predict low flows and flood runoff in ungauged catchments. The aim is to learn from the similarities and differences between catchments in different places, and to interpret the differences in performance in terms of the underlying climate-landscape controls. The assessment is performed at two levels. The Level 1 assessment is a meta-analysis of 14 low flow prediction studies reported in the literature involving 3112 catchments, and 20 flood prediction studies involving 3023 catchments. The Level 2 assessment consists of a more focused and detailed analysis of individual basins from selected studies from Level 1 in terms of how the leave-one-out cross-validation performance depends on climate and catchment characteristics as well as on the regionalisation method. The results indicate that both flood and low flow predictions in ungauged catchments tend to be less accurate in arid than in humid climates and more accurate in large than in small catchments. There is also a tendency towards a somewhat lower performance of regressions than other methods in those studies that apply different methods in the same region, while geostatistical methods tend to perform better than other methods. Of the various flood regionalisation approaches, index methods show significantly lower performances in arid catchments than regression methods or geostatistical methods. For low flow regionalisation, regional regressions are generally better than global regressions.

Salinas, Jose Luis; Laaha, Gregor; Rogger, Magdalena; Parajka, Juraj; Viglione, Alberto; Sivapalan, Murugesu; Bloeschl, Guenter

2013-04-01

273

Comparative assessment of predictions in ungauged basins - Part 1: Runoff-hydrograph studies  

NASA Astrophysics Data System (ADS)

The objective of this assessment is to compare studies predicting runoff hydrographs in ungauged catchments. The aim is to learn from the differences and similarities between catchments in different locations, and to interpret the differences in performance in terms of the underlying climate and landscape controls. The assessment is performed at two levels. The Level 1 assessment is a meta-analysis of 34 studies reported in the literature involving 3874 catchments. The Level 2 assessment consists of a more focused and detailed analysis of individual basins from selected studies from Level 1 in terms of how the leave-one-out cross-validation performance depends on climate and catchment characteristics as well as on the chosen regionalisation method. The results indicate that runoff-hydrograph predictions in ungauged catchments tend to be more accurate in humid than in arid catchments and more accurate in large than in small catchments. The dependence of performance on elevation differs by regions and depends on how aridity varies with elevation and air temperature. The effect of the parameter regionalisation method on model performance differs between studies. However, there is a tendency towards a somewhat lower performance of regressions than other methods in those studies that apply different methods in the same region. In humid catchments spatial proximity and similarity methods perform best while in arid catchments similarity and parameter regression methods perform slightly better. For studies with a large number of catchments (dense stream gauge network) there is a tendency for spatial proximity and geostatistics to perform better than regression or regionalisation based on simple averaging of model parameters from gauged catchments. There was no clear relationship between predictive performance and the number of regionalised model parameters. The implications of the findings are discussed in the context of model building.

Parajka, J.; Viglione, A.; Rogger, M.; Salinas, J. L.; Sivapalan, M.; Blöschl, G.

2013-05-01

274

Phosphorus sources and losses in two arable catchments and implications for catchment management  

NASA Astrophysics Data System (ADS)

Multi-scale catchment experiments allow assessment of the impact of policy measures on nutrient losses from agriculture and water quality and testing of conceptual models of nutrient loss. The potential for catchment-specific responses to be extrapolated to similar catchments country-wide can then help guide future policy measures to achieve water quality targets, such as those in the EU Water Framework Directive (WFD). This paper presents results from the Agricultural Catchments Programme; an integrated advisory/research programme working with stakeholders to assess the efficacy of Ireland's National Action Programme (NAP) of measures in meeting the targets of the Nitrates Directive and WFD. Results are presented for P sources and losses over two water years in two catchments (9.5 and 11.2 km2) with intensive arable agriculture but contrasting soil drainage and geology and resultant hydrologic and nutrient transfer pathways. Phosphorus source pressures were characterised in terms of field-scale soil P status and P balances. Phosphorus loss was characterised in terms of P concentration and loads monitored with high-resolution bank-side analysers. Despite having similar P soil status (18-19 % in excess of agronomic optimum), P losses were much greater from the catchment with more poorly drained soils (0.7 kg ha-1 yr-1) than from the catchment with more freely drained soils (0.2 kg ha-1 yr-1). This paper considers the factors controlling P loss in the two catchments (farm nutrient management, soils, topography and hydrology) to explain the differences between the two catchments and the spatio-temporal variability observed. Agricultural and non-agricultural point sources, in addition to diffuse agricultural sources, are considered. Although both catchments are subject to the same NAP measures, the outcomes, in terms of both P loads and concentrations, showed that inter-annual hydrological patterns and inter-catchment hydrological properties are critical. This highlights the importance of considering soil, geological and landscape factors when considering policy measures to decrease nutrient losses to water and improve the sustainability of agricultural production systems.

Murphy, P. N. C.; Melland, A. R.; Mellander, P.-E.; Shortle, G.; Wall, D.; Jordan, P.

2012-04-01

275

Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Average Annual Daily Minimum Temperature, 2002  

USGS Publications Warehouse

This data set represents the average monthly minimum temperature in Celsius multiplied by 100 for 2002 compiled for every catchment of NHDPlus for the conterminous United States. The source data were the Near-Real-Time High-Resolution Monthly Average Maximum/Minimum Temperature for the Conterminous United States for 2002 raster dataset produced by the Spatial Climate Analysis Service at Oregon State University. The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States. The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, contains NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus Production Units 4, 5, 7 and 9. MRB4, covering the Missouri River basins, contains NHDPlus Production Units 10-lower and 10-upper. MRB5, covering the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins, contains NHDPlus Production Units 8, 11 and 12. MRB6, covering the Rio Grande, Colorado and Great Basin River basins, contains NHDPlus Production Units 13, 14, 15 and 16. MRB7, covering the Pacific Northwest River basins, contains NHDPlus Production Unit 17. MRB8, covering California River basins, contains NHDPlus Production Unit 18.

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

276

Attributes for NHDPlus catchments (version 1.1) for the conterminous United States: Average Annual Daily Maximum Temperature, 2002  

USGS Publications Warehouse

This data set represents the average monthly maximum temperature in Celsius multiplied by 100 for 2002 compiled for every catchment of NHDPlus for the conterminous United States. The source data were the Near-Real-Time High-Resolution Monthly Average Maximum/Minimum Temperature for the Conterminous United States for 2002 raster dataset produced by the Spatial Climate Analysis Service at Oregon State University. The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States. The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, contains NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus Production Units 4, 5, 7 and 9. MRB4, covering the Missouri River basins, contains NHDPlus Production Units 10-lower and 10-upper. MRB5, covering the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins, contains NHDPlus Production Units 8, 11 and 12. MRB6, covering the Rio Grande, Colorado and Great Basin River basins, contains NHDPlus Production Units 13, 14, 15 and 16. MRB7, covering the Pacific Northwest River basins, contains NHDPlus Production Unit 17. MRB8, covering California River basins, contains NHDPlus Production Unit 18.

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

277

Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Average Monthly Precipitation, 2002  

USGS Publications Warehouse

This data set represents the average monthly precipitation in millimeters multiplied by 100 for 2002 compiled for every catchment of NHDPlus for the conterminous United States. The source data were the Near-Real-Time Monthly High-Resolution Precipitation Climate Data Set for the Conterminous United States (2002) raster dataset produced by the Spatial Climate Analysis Service at Oregon State University. The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States. The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, contains NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus Production Units 4, 5, 7 and 9. MRB4, covering the Missouri River basins, contains NHDPlus Production Units 10-lower and 10-upper. MRB5, covering the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins, contains NHDPlus Production Units 8, 11 and 12. MRB6, covering the Rio Grande, Colorado and Great Basin River basins, contains NHDPlus Production Units 13, 14, 15 and 16. MRB7, covering the Pacific Northwest River basins, contains NHDPlus Production Unit 17. MRB8, covering California River basins, contains NHDPlus Production Unit 18.

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

278

Sediment Delivery Assessment for a Transboundary Mediterranean Catchment: The Example of Nestos River Catchment  

Microsoft Academic Search

Nestos River flows through Bulgaria and Greece and discharges into the North Aegean Sea. Its total catchment area is around\\u000a 6,200 km2, while the mean annual precipitation and runoff are 680 mm and 40 m3\\/s, respectively. The Hellenic part of the catchment has undergone a substantial hydroelectric development, since two dams\\u000a associated with major hydropower pumped-storage facilities are in operation. The main objective

Demetris Zarris; Marianna Vlastara; Dionysia Panagoulia

279

Ecosystem Services Derived from Headwater Catchments  

EPA Science Inventory

We used data from the USEPA?s wadeable streams assessment (WSA), US Forest Service?s forest inventory and analysis (FIA), and select USFS experimental forests (EF) to investigate potential ecosystems services derived from headwater catchments. C, N, and P inputs to these catchmen...

280

Hydrological Modelling of Small Catchments Using Swat  

NASA Astrophysics Data System (ADS)

The data from a 142ha catchment in Eastern England(Colworth, Bedfordshire)are be- ing used to investigate the performance of the USDA SWAT software for modelling hydrology of small catchments. Stream flow at the catchment outlet has been mon- itored since October 1999. About 50% of the total catchment is directly controlled within one farm and a rotation of wheat, oil seed rape, grass, linseed, beans and peas is grown. Three years of stream flow and climate data are available. Calibration and validation of stream flow was carried out with both runoff modelling options in the SWAT model (USDA curve number method and the Green and Ampt method). The Nash and Sutcliffe efficiencies for the calibration period were 66% and 63% respec- tively. The performance of SWAT was better in the validation period as a whole, with regard to timing of peaks, baseflow values and Nash and Sutcliffe efficiency. An ef- ficiency of 70% was obtained using the curve number method, which is comparable with the efficiencies obtainable with more complex models. Despite this performance, SWAT is under predicting stream flow peaks. A detailed investigation of important model components, has allowed us to identify some of the reasons for under predic- tion of stream flow peaks.

Kannan, N.; White, S. M.; Worrall, F.; Groves, S.

281

Catchment scale multi-objective flood management  

Microsoft Academic Search

Rural land management is known to affect both the generation and propagation of flooding at the local scale, but there is still a general lack of good evidence that this impact is still significant at the larger catchment scale given the complexity of physical interactions and climatic variability taking place at this level. The National Trust, in partnership with the

Steve Rose; Peter Worrall; Zdenka Rosolova; Gene Hammond

2010-01-01

282

Sediment yield model implementation based on check dam infill stratigraphy in a semiarid Mediterranean catchment  

NASA Astrophysics Data System (ADS)

Soil loss and sediment transport in Mediterranean areas are driven by complex non-linear processes which have been only partially understood. In order to facilitate the comprehension of these phenomena, distributed models can be very helpful tools for sediment yield estimation. In this work, a modelling approach is proposed to reproduce and evaluate erosion and sediment yield processes in a Mediterranean catchment (Rambla del Poyo, Valencia, Spain). Due to the lack of sediment transport records for model calibration and validation, a detailed description of the alluvial stratigraphy infilling a check dam that drains a 12.9 km2 sub-catchment was used as an indirect evidence of sediment yield data. These dam infill sediments showed evidences of at least 15 depositional events (floods) over the time period 1990-2009. The TETIS-SED model, a distributed conceptual hydrological and sediment model, was coupled to the Sediment Trap Efficiency for Small Ponds (STEP) model for reproducing reservoir retention, and it was calibrated and validated using the sedimentation volume estimated for the depositional units associated with discrete runoff events. The results show relatively low net erosion rates compared to other Mediterranean catchments (14 t km-2 yr-1), probably due to the extensive outcrops of limestone bedrock and rather homogeneous vegetation cover, and confirms the ephemeral behaviour of the stream. The modelled sediment production rates offer satisfactory results, further supported by palaeohydrological evidences, showing its great potential for the quantitative analysis of sediment dynamics in ungauged Mediterranean basins.

Bussi, G.; Rodríguez-Lloveras, X.; Francés, F.; Benito, G.; Sánchez-Moya, Y.; Sopeña, A.

2013-03-01

283

Salt mobilisation processes from a salinised catchment featuring a perennial stream  

NASA Astrophysics Data System (ADS)

SummaryStream salinity is a major concern in the Murray-Darling Basin (MDB) for its impact upon irrigation, urban water supplies and biota. This study investigated the source of salt to a perennial stream in a small salt affected catchment in the eastern MDB. Using a Bayesian mixing model on an event basis, it was found that between one third and two thirds of the salt came from the near surface zone (0-0.2 m) and the remainder came from groundwater. For the year 2006, 38% of the salt exported from the catchment was sourced from the near surface zone. The source of water for the near surface zone comprises less than 1% of the catchment area and is associated with a saline seep/scald. This area becomes saturated during the winter months when saturated overland flow is generated. This mechanism for salt delivery to a stream is not explicitly included in most models used to generate management scenarios for the mitigation of stream salinity. There is a growing body of evidence to suggest that the near surface zone is very important for salt delivery to streams, therefore models should explicitly incorporate this mechanism.

Hughes, J. D.; Crosbie, R. S.; van de Ven, R. J.

2008-12-01

284

Catchment features controlling nitrogen dynamics in running waters above the tree line (central Italian Alps)  

NASA Astrophysics Data System (ADS)

The study of nitrogen cycling in mountain areas has a long tradition, as it was applied to better understand and describe ecosystem functioning, as well as to quantify long-distance effects of human activities on remote environments. Nonetheless, very few studies, especially in Europe, have considered catchment features controlling nitrogen dynamics above the tree line with focus on running waters. In this study, relationships between some water chemistry descriptors - including nitrogen species and dissolved organic carbon (DOC) - and catchment characteristics were evaluated for a range of sites located above the tree line (1950-2650 m a.s.l.) at Val Masino, in the central Italian Alps. Land cover categories as well as elevation and slope were assessed at each site. Water samples were collected during the 2007 and 2008 snow free periods, with a nearly monthly frequency. In contrast to dissolved organic nitrogen, nitrate concentrations in running waters showed a spatial pattern strictly connected to the fractional extension of tundra and talus in each basin. Exponential models significantly described the relationships between maximum NO3 and the fraction of vegetated soil cover (negative relation) and talus (positive relation), explaining almost 90% of nitrate variation in running waters. Similarly to nitrate but with an opposite behavior, DOC was positively correlated with vegetated soil cover and negatively correlated with talus. Therefore, land cover can be considered one of the most important factors affecting water quality in high-elevation catchments with contrasting effects on N and C pools.

Balestrini, R.; Arese, C.; Freppaz, M.; Buffagni, A.

2013-03-01

285

Catchment features controlling nitrogen dynamics in running waters above the tree line (Central Italian Alps)  

NASA Astrophysics Data System (ADS)

The study of nitrogen cycling in mountain areas has a long tradition, both to better understand and describe ecosystem functioning and to quantify the long-distance effect of human activities on remote environments. Nonetheless, especially in Europe, very few studies paid attention on catchment features controlling nitrogen dynamics above the tree line, with focus on running waters. In this study, relationships between some water chemistry descriptors, including nitrogen species and dissolved organic carbon (DOC), and catchment characteristics were evaluated for a range of sites located above the tree line (1950-2650 m a.s.l.) at Val Masino, in the Central Italian Alps. Land cover categories as well as elevation and slope were assessed at each site. Water samples were collected during the 2007 and 2008 snow free periods, with a nearly monthly frequency. Differently to dissolved organic nitrogen, nitrate concentration in running waters showed a spatial pattern strictly connected to the fractional extension of tundra and talus in each basin. Exponential models significantly described the relationships between maximum NO3-N and the fraction of vegetated soil cover (negative relation) and talus (positive relation), explaining almost 90% of nitrate variation in running waters. Similarly to nitrate, but with an opposite behavior, DOC was positively correlated with vegetated soil cover and negatively correlated with talus. Therefore, land cover can be considered one of the most important factors affecting water quality in high elevation catchments, with a contrasting effect on N and C pools.

Balestrini, R.; Arese, C.; Freppaz, M.; Buffagni, A.

2012-09-01

286

Modelling of catchment inflows into Lake Victoria: Uncertainties in rain-runoff modelling for Nzoia River  

NASA Astrophysics Data System (ADS)

Climate and soil characteristics vary quite considerably around the Lake Victoria basin in East Africa which results in high spatial and temporal variability in catchment inflows into the lake. However, the data available for estimating the inflows are usually sparsely distributed and error prone. As a result modeled estimates of the flows are highly uncertain. This could explain early difficulties in reproducing the lake water balance. A new approach for estimating the catchment inflow was developed that implicitly takes into account the various sources of data and modelling uncertainties. Monte Carlo simulation within the GLUE framework was applied to WASMOD model using uniformly sampled parameter sets. The performance of the model was assessed by comparing simulated flow and observed flow using two performance criteria. By splitting the input data into calibration and prediction stages, we assessed the predictive uncertainty using a Bayesian averaging method. The approach was tested on River Nzoia, one of the main rivers that flow into Lake Victoria. The results showed that the proposed approach reveals some interesting possibilities in modeling catchment inflows. Model performance was good with Nash-Sutcliffe values that were as high as 0.85. For data covering the period 1973-1989, simulated flows bounded measured flows 86% of the time. However, the model failed for data covering the period 1990-1995 and our investigation showed that this was probably caused by uncertainties in measured flow.

Kizza, M.; Rodhe, A.; Xu, C.-Y.

2009-04-01

287

A simple framework for relating variations in runoff to variations in climatic conditions and catchment properties  

NASA Astrophysics Data System (ADS)

We use the Budyko framework to calculate catchment-scale evapotranspiration (E) and runoff (Q) as a function of two climatic factors, precipitation (P) and evaporative demand (Eo = 0.75 times the pan evaporation rate), and a third parameter that encodes the catchment properties (n) and modifies how P is partitioned between E and Q. This simple theory accurately predicted the long-term evapotranspiration (E) and runoff (Q) for the Murray-Darling Basin (MDB) in southeast Australia. We extend the theory by developing a simple and novel analytical expression for the effects on E and Q of small perturbations in P, Eo, and n. The theory predicts that a 10% change in P, with all else constant, would result in a 26% change in Q in the MDB. Future climate scenarios (2070-2099) derived using Intergovernmental Panel on Climate Change AR4 climate model output highlight the diversity of projections for P (±30%) with a correspondingly large range in projections for Q (±80%) in the MDB. We conclude with a qualitative description about the impact of changes in catchment properties on water availability and focus on the interaction between vegetation change, increasing atmospheric [CO2], and fire frequency. We conclude that the modern version of the Budyko framework is a useful tool for making simple and transparent estimates of changes in water availability.

Roderick, Michael L.; Farquhar, Graham D.

2011-12-01

288

Quantitative reconstruction of past soil erosion in the Kirschgraben catchment (Spessart mountains, Central Europe)  

NASA Astrophysics Data System (ADS)

An important problem in Holocene landscape reconstruction is quantifying the relative roles of climatic change and human impact. This project aims to quantify and mass-balance sediment flux in high temporal and spatial resolution, therefore a relatively small gully catchment (Kirschgraben) in the low mountain range Spessart (Germany, Lower Franconia) was chosen as a research area. The catchment is 42 ha in size and total relief is ~200 m. Bedrock is composed of Bunter Sandstone, large areas of which are loess mantled. In the intersection between Kirschgraben fan and the alluvial plain of the Elsava River a moated archaeological site was recently excavated. On the basis of process-based stratigraphy and preliminary chronology, a detailed sequence of landscape changes can be interpreted. Gully incision into Pleistocene sand and gravel sediments during early Holocene resulted in rapid fan development. Non-deposition on the fan surface and minor infilling of the gully system suggests relative catchment stability persisted during prehistoric times, at least until the early iron ages, when human occupation of the fan surface is first recorded. The first evidence of human impact, although minor, is represented by thin colluvial layers on the lower slopes during late Neolithic period. Subsequently, almost the entire catchment has been under agricultural use from the early medieval periods on, and well preserved within field terraces along ancient tenure borders. These features demonstrate widespread and intensive soil loss from the slopes, and eroded material is also preserved in various sediment traps within the catchment. Charcoal production in the catchment probably began at the same time as the widespread soil loss, and lasted until ca. 1900 AD. Anthracological investigations provide the opportunity to reconstruct the vegetation composition on a local scale, and is combined with paleobotanical macro remains and pollen analysis. Initial results indicate a rotating wood - pasture - agriculture cultivation system was used within the catchment on slopes with a north west aspect. The fan area was again occupied in the form of a medieval castle from around 1200 until 1462 AD, coinciding with a rise in the ground water table (due to either dam construction in the trunk stream, a decrease in evapotranspiration, or both) intense gully cut and fill cycles, and high slope instability in the catchment. These erosional processes continue due to the persistence of agricultural and pastural land use and also intense charcoal production until the present day. Initial quantification of the sediment masses in the catchment suggest that most of the eroded material is stored in the gully infills and lower slopes and are not excavated to the fan or the trunk stream. Further work will improve the spatial mass-balance calculations, and in combination with the chronological data, will enable the quantification of a high resolution Holocene sediment flux for the catchment.

Kranz, Annegret; Bork, Hans-Rudolf; Nelle, Oliver; Müller, Ulrich; Fuchs, Markus; Fuelling, Alexander

2010-05-01

289

Quantifying the performance of two conceptual models for snow dominated catchments in Austria and Turkey  

NASA Astrophysics Data System (ADS)

In many mountainous regions, snowmelt makes significant contribution to streamflow, particularly during spring and summer months. Understanding the magnitude and timing of this contribution and hydrological forecasts are essential for a range of purposes concerning the implications with water resources management. Conceptual hydrological models have been widely applied for mountain catchments both for operational and scientific applications. Hydrologiska Byran Vattenbalansavdelning (HBV) and Snowmelt Runoff Model (SRM) are selected in this study as the commonly used conceptual models in hydrological modeling forecasting for a number of basins in several countries. Moreover, this selection is also supported by the experiences on the improvement and application in remote sensing techniques in snow dominated regions. The greatest similarity between the two models is that each uses a temperature index method to predict melt rate whereas the greatest difference lies in the way snow cover is handled. In mountainous regions, data limitations prevent detailed understanding of the variability of snow cover and melt. In situ snowpack measurements are sparsely distributed relative to snowpack heterogeneity therefore, to supplement ground measurements; remotely sensed images of snow covered area (SCA) provide useful information for runoff prediction during the snowmelt season. SCA has been used as a direct input to SRM and as a means of checking the internal validity for HBV model. Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow cover products with 500 m spatial resolution are used to derive SCA data in this study. A number of studies have been reported in the literature indicated that the model performance can vary depending on several factors, including the scale and characteristics of the catchment, availability of the data required and runoff producing mechanism. Therefore, five different catchments including data scare and rich basins, areas and reliefs changing in between 1000-10250 km2and 1250-3050 m, respectively, in Austria and Turkey are tested to understand the impact of catchment properties on model simulations. Both models are used to simulate runoff for the years 2001-2010 with the period of 2001-2008 and 2009-2011 for model calibration and validation, respectively. The overall model calibration performance evaluated with the model efficiency is above 0.70 and volume difference less than 10% for both of the models. Discussion of results are supervised to reflect the general debates in hydrologic modeling in terms of parameters and calibration, internal validation, the value and limitations of using satellite derived data, impact of different catchment properties with emphasis on the contrasting treatments in two widely used hydrologic models, SRM and HBV.

Sensoy, Aynur; Parajka, Juraj; Coskun, Cihan; Sorman, Arda; Ertas, Cansaran

2014-05-01

290

Response of basic hydro-chemical indicators to rainfall-runoff events in forest disturbed catchments in upper Vydra, Central Sumava Mountains  

NASA Astrophysics Data System (ADS)

The quantity and quality of streamflow in forested basins in montane regions is complex due to spatial and temporal hydrological processes and land cover changes. Basic hydro-chemical parameters can be used as indicators to understand the contributions of sub-streams, hydrological behaviors, and changing runoff sources to the streamflow. The relationship between the indicators and discharge provide further information on runoff dynamics in terms of both quantity and quality. We therefore used three basic hydro-chemical parameters: water temperature (WT), pH, and electronic conductivity (EC) in six experimental catchments within the upper Vydra basin, Central Sumava Mountains. In the 6 studied sub-catchments, water stages, WT, EC, and pH have been continuously monitored at the catchment outlets and corresponding meteorological parameters such as precipitation and air temperature have been collected in 10-minute interval at 3 stations since 2009. Each of these 6 sub-catchments has an area around 2-5 km2 and covers different types of physiographic conditions, land cover related to forest intensity and the type of disturbance. We aim to investigate inter-relationship between the indicators (WT, pH, and EC) and the streamflow (Q) response to different rainfall-runoff events. The sub-catchments have generally a relatively low pH (5.5-6.6) and EC (24-45 uS/cm), while the upstream has lower pH and higher EC than downstream and the outlet of Vydra basin at Modrava. The upstream-downstream gradients could be resulting from the peat bog proportion, which is higher in the upstream spring area. Different rainfall-runoff events, dry periods, snow melting periods, wet-periods, long-term rainfall, storm events, and unimodal and bimodal flood waves, are causing different responses of Q and studied indicators. Moreover, the response is varying in the studied catchments with different forest cover. In general, the EC performed in a positive correlation with Q, while performing in a negative correlation with pH. These responses to the rainfall-runoff events, the EC-loop and the pH-loop give information about the streamflow pathways in different catchments with varying forest proportions. The contribution of this study gives an alternative to high-cost techniques and an application of using simple natural tracers to indirectly quantify rainfall-runoff processes in stream and the role of sub-streams to the whole basin. Key words: streamflow, electrical conductivity, pH, water temperature, rainfall-runoff events, Vydra basin

Su, Ye; Langhammer, Jakub; Kaiglová, Jana

2014-05-01

291

Spatial variability of herbicide mobilisation and transport at catchment scale: insights from a field experiment  

NASA Astrophysics Data System (ADS)

During rain events, herbicides can be transported from their point of application to surface waters where they may harm aquatic organisms. Since the spatial pattern of mobilisation and transport is heterogeneous, the contributions of different fields to the herbicide load in the stream may differ considerably within one catchment. Therefore, the prediction of contributing areas could help to target mitigation measures efficiently to those locations where they reduce herbicide pollution the most. Such spatial predictions require sufficient insight into the underlying transport processes. To improve the understanding of the process chain of herbicide mobilisation on the field and the subsequent transport through the catchment to the stream, we performed a controlled herbicide application on corn fields in a small agricultural catchment (ca. 1 km2) with intensive crop production in the Swiss Plateau. For two months after application in 2009, water samples were taken at different locations in the catchment (overland flow, tile drains and open channel) with a high temporal resolution during rain events. We also analysed soil samples from the experimental fields and measured discharge, groundwater level, soil moisture and the occurrence of overland flow at several locations. Several rain events with varying intensities and magnitudes occurred during the study period. Overland flow and erosion were frequently observed in the entire catchment. Infiltration excess and saturation excess overland flow were both observed. However, the main herbicide loss event was dominated by infiltration excess. This is in contrast to earlier studies in the Swiss Plateau, demonstrating that saturation excess overland flow was the dominant process. Despite the frequent and wide-spread occurrence of overland flow, most of this water did not directly reach the channel. It mostly got retained in small sinks in the catchment. From there, it reached the stream via macropores and tile drains. Manholes of the drainage system and catch basins for road and farmyard runoff acted as additional shortcuts to the stream. Although fast flow processes like overland and macropore flow reduce the influence of herbicide properties due to short travel times, sorption properties influenced the herbicide transfer from ponding overland flow to tile drains (macropore flow). However, no influence of sorption was observed during the mobilisation of the herbicides from soil to overland flow. These two observations on the role of herbicide properties contradict, to some degrees, previous findings. They demonstrate that valuable insight can be gained by spatially detailed observations along the flow paths.

Doppler, T.; Camenzuli, L.; Hirzel, G.; Krauss, M.; Lück, A.; Stamm, C.

2012-02-01

292

Homogenization of Spatial Patterns of Hydrologic Response in Artificially Drained Agricultural Catchments  

NASA Astrophysics Data System (ADS)

Anthropogenic modifications to the landscape, with agricultural activities being a primary driver, have resulted in significant alterations to the hydrologic cycle. Artificial drainage, including surface and subsurface drainage (tile drains), is one of the most extensive manipulations in agricultural landscapes and thus is expected to provide a distinct signature of anthropogenic modification. This study adopts a data synthesis approach in an effort to characterize the signature of artificial subsurface drainage. Daily discharge data from 24 basins across the state of Iowa, which encapsulate a range of anthropogenic modifications, are assessed using a variety of flow metrics. Results indicate that the presence of artificial subsurface drainage leads to a homogenization of landscape hydrologic response. Non-tiled watersheds exhibit a decrease in the area-normalized peak discharge and an increase in the baseflow ratio (baseflow/streamflow) with increases in the spatial scale, while scale invariance is apparent in tiled basins. Within-basin variability in hydrograph recession coefficients also appears to decrease with increases in the proportion of the catchment that is artificially drained. Finally, the differences between tiled and non-tiled landscapes disappear at scales greater than approximately 2200 km2, indicating that this may be a threshold scale for studying the effects of tile drainage. This decrease in within-basin variability and the scale invariance of hydrologic metrics in artificially drained watersheds are attributed to the creation of a bypass flow hydrologic pathway that bypasses the complexity of the catchment travel paths. Spatial homogeneity in responses implies that it may be possible to develop more parsimonious hydrologic models for these regions.

Boland, S. J.; Basu, N. B.; Schilling, K.

2013-12-01

293

Characterizing hot spots throughout the catchment  

NASA Astrophysics Data System (ADS)

Few catchments in the world are left truly undisturbed. Rather, they are under anthropogenic stress for a variety of reasons ranging from climate forcing to meeting the basic water allocation needs of the population. Reduction in the number of inundation areas has significantly decreased the nutrient and organic matter retention capacity along the river corridor, with major consequences for the both the riverine and coastal ecosystems. Cumulative stress may build up to a "tipping point" which can cause a change or set of changes which could occur non-linearly. In order to mitigate the environmental stress on these ecosystems, management plans are created to balance the needs of the dependent populations and those of ecology. While these catchment-wide plans aim to improve the ecological function of aquatic areas over the large scale, this sledge-hammer approach ignores the inherent heterogeneity in the catchment. Societal (and policy) decisions involve more than abiotic quantification of water storage and flow. A more encompassing ecohydrological view facilitates a more rounded policy framework that has flexibility to accommodate multiple social drivers, and one that can accommodate an "ecosystem improvement" rather than single species improvement. Not every spot in the landscape is equally valuable for specific societal values. Areas of high activity may provide the resilience capacity necessary to prevent catastrophic changes. In times of ecological instability, ecosystem resilience is of paramount importance in maintaining essential ecosystem services. Hot spots of biogeochemical cycling will occur where unique situations arise, such as areas of surface and groundwater interaction, creating spots of localized, high activity. In order to understand the systems' potential to support various habitat niches in the large scale, the identification of specific hot spots or hot moments is necessary. A basal understanding of the concurrent biogeochemical cycles enables the subsequent predictions of the alternative ecosystem responses. This study aims to understand the where and why of hot spots in selected catchments in southeastern Australia and Midwestern United States. The ecosystem response to changes in the catchment will be generated based on various biotic parameters, with the ultimate goal of incorporation into a policy framework at the catchment scale.

Welti, N.; Lockington, D.; Jakeman, T.; Hunt, R.

2012-04-01

294

Similarity Analysis between near surface soil moisture and streamflow during recession events in an alpine catchment  

NASA Astrophysics Data System (ADS)

Spatial and temporal variability of near surface soil moisture is important for understanding streamflow generation in high altitude mountain catchments since antecedent soil moisture plays an important role in the timing of runoff. For relatively small to medium sized catchments, the spatial variability of near surface soil moisture is hard to capture with remote sensing techniques and distributed point measurements are needed. Linking local measurements of soil moisture with integrating catchment scale streamflow measurements remains a great challenge in hydrological modeling. Since 2008, an alpine watershed of 20.4 km2 has been intensively monitored in the Swiss Alps, with a deployment of a network of wireless meteorological stations, measuring soil moisture along with other meteorological forcings. The discharge is monitored at three different sites. We present some preliminary results from a statistical analysis linking the spatial variation of the soil moisture, measured at 20 and 40 cm, with the variation of the streamflow in the particular case of recession events. A classic parameterization of recession events relating the variation of the discharge dQ-dt to the discharge Q by |dQ-dt|? Q? is used and transposed to soil moisture data. The parameterized soil moisture variation is then partitioned into runoff and evapotranspiration leading to better knowledge of local processes at the hillslope scale.

Mutzner, Raphael; Weijs, Steven V.; Rinaldo, Andrea; Parlange, Marc B.

2013-04-01

295

A 1000-year history of large floods in the Upper Ganga catchment, central Himalaya, India  

NASA Astrophysics Data System (ADS)

Determining the frequency, magnitude and causes of large floods over long periods in the flood-prone Himalaya is important for estimating the likelihood of future floods. A thousand year record (with some information from 2600 years ago) of the frequency and some estimates of velocities and discharges of large floods has been reconstructed in the Upper Ganga catchment, India, using written reports, litho-stratigraphy and sedimentology, and dated by optical and radiocarbon methods. In the Upper Ganga catchment rainfall triggers large landslides that dam rivers and release large amounts of water when they burst, thereby amplifying the effects of rainfall. The large floods in the catchment may be the result of landslide dam bursts rather than glacial lake bursts, and these are likely to continue and possibly worsen as the monsoon intensifies over the next century. However preliminary information suggests that the recent devastating flood of June 2013 was the result of heavy rainfall not landslide dam bursts. The frequency record is non-random and shows a high frequency between AD 1000 and AD 1300 (omitting uncertainties), then a low frequency until a cluster of floods occurred about 200 years ago, then increased frequency. This temporal pattern is like but not identical with that in Peninsular India, and both appear to be the result of variations in the monsoon.

Wasson, R. J.; Sundriyal, Y. P.; Chaudhary, Shipra; Jaiswal, Manoj K.; Morthekai, P.; Sati, S. P.; Juyal, Navin

2013-10-01

296

Application of Swat (Soil and Water Assessment Tool) to Four Nested Grassland Catchments  

NASA Astrophysics Data System (ADS)

The process of monitoring and modelling the physical and chemical dynamics of stream catchments has become a major issue of priority with hydrologists worldwide over the past few years. There is now a growing concern for the decline in stream water quality as a result of excess phosphorus concentrations and consequently much emphasis is presently being placed on the implementation of models to trace and predict the paths of surface and subsurface flow which assist in agri-chemical transport. One such model is SWAT (the soil and water assessment tool) (Arnold et al., 1998) which was developed to allow continuous-time simulations with a high level of spatial detail by permitting the division of a catchment area into grid cells. The primary objective of this particular study was to apply and test the latest version of SWAT (version 2000) to estimate flow, and phosphorus loadings for the Dripsey Catchment stream network. Similar studies carried out in the past have generally been implemented on large river basins. The area of interest concerned in this case however is much smaller consisting of four nested grassland catchments (15ha, 25ha, 2km2 and 15km2). Field instrumentation includes flow and water quality monitoring stations (i.e.both discrete and composite samples) at four sites in addition to a meteorological station located in the most upland site (15ha) for measuring rainfall, temperature, wind speed, radiation and soil moisture. The Nash-Sutcliffe coefficient for model validation revealed that the predicted average daily flow and phosphorus loading fell reasonably well within the range of measured values.

Horgan, F. M.

2002-12-01

297

Sediment yield model implementation based on check dam infill stratigraphy in a semiarid Mediterranean catchment  

NASA Astrophysics Data System (ADS)

Soil loss and sediment transport in Mediterranean areas are driven by complex non-linear processes which have been only partially understood. Distributed models can be very helpful tools for understanding the catchment-scale phenomena which lead to soil erosion and sediment transport. In this study, a modelling approach is proposed to reproduce and evaluate erosion and sediment yield processes in a Mediterranean catchment (Rambla del Poyo, Valencia, Spain). Due to the lack of sediment transport records for model calibration and validation, a detailed description of the alluvial stratigraphy infilling a check dam that drains a 12.9 km2 sub-catchment was used as indirect information of sediment yield data. These dam infill sediments showed evidences of at least 15 depositional events (floods) over the time period 1990-2009. The TETIS model, a distributed conceptual hydrological and sediment model, was coupled to the Sediment Trap Efficiency for Small Ponds (STEP) model for reproducing reservoir retention, and it was calibrated and validated using the sedimentation volume estimated for the depositional units associated with discrete runoff events. The results show relatively low net erosion rates compared to other Mediterranean catchments (0.136 Mg ha-1 yr-1), probably due to the extensive outcrops of limestone bedrock, thin soils and rather homogeneous vegetation cover. The simulated sediment production and transport rates offer model satisfactory results, further supported by in-site palaeohydrological evidences and spatial validation using additional check dams, showing the great potential of the presented data assimilation methodology for the quantitative analysis of sediment dynamics in ungauged Mediterranean basins.

Bussi, G.; Rodríguez-Lloveras, X.; Francés, F.; Benito, G.; Sánchez-Moya, Y.; Sopeña, A.

2013-08-01

298

An evaluation of catchment-scale phosphorus mitigation using load apportionment modelling.  

PubMed

Functional relationships between phosphorus (P) discharge and concentration mechanisms were explored using a load apportionment model (LAM) developed for use in a freshwater catchment in Ireland with fourteen years of data (1995-2008). The aim of model conceptualisation was to infer changes in point and diffuse sources from catchment P loading during P mitigation, based upon a dataset comprising geospatial and water quality data from a 256km(2) lake catchment in an intensively farmed drumlin region of the midlands of Ireland. The model was calibrated using river total P (TP), molybdate reactive P (MRP) and runoff data from seven subcatchments. Temporal and spatial heterogeneity of P sources existed within and between subcatchments; these were attributed to differences in agricultural intensity, soil type and anthropogenically-sourced effluent P loading. Catchment rivers were sensitive to flow regime, which can result in eutrophication of rivers during summer and lake enrichment from frequent flood events. For one sewage impacted river, the LAM estimated that point sourced P contributed up to of 90% of annual MRP load delivered during a hydrological year and in this river point P sources dominated flows up to 92% of days. In the other rivers, despite diffuse P forming a majority of the annual P exports, point sources of P dominated flows for up to 64% of a hydrological year. The calibrated model demonstrated that lower P export rates followed specific P mitigation measures. The LAM estimated up to 80% decreases in point MRP load after enhanced P removal at waste water treatments plants in urban subcatchments and the implementation of septic tank and agricultural bye-laws in rural subcatchments. The LAM approach provides a way to assess the long-term effectiveness of further measures to reduce P loadings in EU (International) River Basin Districts and subcatchments. PMID:21429559

Greene, S; Taylor, D; McElarney, Y R; Foy, R H; Jordan, P

2011-05-01

299

Characterisation of dispersion mechanisms in an urban catchment using a deterministic spatially distributed direct hydrograph travel time model  

NASA Astrophysics Data System (ADS)

The link between stream network structure and hydrologic response for natural basins has been extensively studied. It is well known that stream network organization and flow dynamics in the reaches combine to shape the hydrologic response of natural basins. Geomorphologic dispersion and hydrodynamic dispersion along with hillslope processes control to a large extent the overall variance of the hydrograph, particularly under the assumption of constant celerity throughout the basin. In addition, a third mechanism referred as to kinematic dispersion becomes relevant when considering spatial variations of celerity. On contrary, the link between the drainage network structure and overall urban terrain, and the hydrologic response in urban catchments has been much less studied. In particular, the characterization of the different dispersion mechanisms within urban areas remains to be better understood. In such areas artificial elements are expected to contribute to the total dispersion due to the variety of geometries and the spatial distribution of imperviousness. This work quantifies the different dispersion mechanisms in an urban catchment, focusing on their relevance and the spatial scales involved. For this purpose we use the Urban Morpho-climatic Instantaneous Unit Hydrograph model, a deterministic spatially distributed direct hydrograph travel time model, which computes travel times in hillslope, pipe, street and channel cells using formulations derived from kinematic wave theory. The model was applied to the Aubeniere catchment, located in Nantes, France. Unlike stochastic models, this deterministic model allows the quantification of dispersion mechanism at the local scale (i.e. the grid-cell). We found that kinematic dispersion is more relevant for small storm events, whereas geomorphologic dispersion becomes more significant for larger storms, as the mean celerity within the catchment increases. In addition, the total dispersion relates to the drainage area in a power law fashion. The kinematic dispersion is dominant until a threshold of 1 km2, where the geomorphologic dispersion becomes more important. Overall hillslopes are responsible for most of the dispersion, while the channels tend to counteract the increase of the geomorphologic dispersion with a negative kinematic dispersion. Finally, a simplification of the catchment structure in terms of the Horton-Strahler classification confirms the results above mentioned, and showed that geomorphologic dispersion is mostly due to high order elements. Overall the results obtained compared well to those hardly found in the literature, and validate the suitability of the U-McIUH model for simulating flow accumulation and hydrograph generation in urban catchments.

Rossel, F.; Gironas, J. A.

2012-12-01

300

Estimating net anthropogenic nitrogen inputs (NANI) in the Lake Dianchi basin of China  

NASA Astrophysics Data System (ADS)

Net anthropogenic nitrogen inputs (NANI) with components of atmospheric N deposition, synthetic N fertilizer, agricultural N fixation and N in net food and feed imports from 15 catchments in the Lake Dianchi basin were determined over an 11-year period (2000-2010). The 15 catchments range in size from 44 km2 to 316 km2 with an average of 175 km2. To reduce uncertainty from scale change methodology, results from data extraction by area-weighting and land use-weighting methods were compared. Results show that the methodology for extrapolating data from the county scale to watersheds has a great influence on NANI computation for catchments in the Lake Dianchi basin, and that estimates of NANI between the two methods have an average difference of 30% on a catchment basis, while a smaller difference (15%) was observed on the whole Lake Dianchi basin basis. The riverine N export has a stronger linear relationship with NANI computed by the land use-weighting method, which we believe is more reliable. Overall, nitrogen inputs assessed by the NANI approach for the Lake Dianchi basin are 9900 kg N km-2 yr-1, ranging from 6600 to 28 000 kg N km-2 yr-1 among the 15 catchments. Synthetic N fertilizer is the largest component of NANI in most subwatersheds. On average, riverine flux of nitrogen in catchments of the Lake Dianchi basin averages 83% of NANI, far higher than generally observed in North America and Europe. Saturated N sinks and a limited capacity for denitrification in rivers may be responsible for this high percentage of riverine N export. Overall, the NANI methodology should be applicable in small watersheds when sufficiently detailed data are available to estimate its components.

Gao, W.; Howarth, R. W.; Hong, B.; Swaney, D. P.; Guo, H. C.

2014-08-01

301

Estimating net anthropogenic nitrogen inputs (NANI) in the Lake Dianchi Basin of China  

NASA Astrophysics Data System (ADS)

Net anthropogenic nitrogen inputs (NANI) with components of atmospheric N deposition, synthetic N fertilizer, agricultural N fixation and N in net food and feed imports from 15 catchments in Lake Dianchi Basin were determined over an 11 year period (2000-2010). The 15 catchments range in size from 44 km2 to 316 km2 with an average of 175 km2. To reduce uncertainty from scale change methodology, results from data extracting by area-weighting and land use-weighting methods were compared. Results show that methodology for extrapolating data from county scale to watersheds has a great influence on NANI computation for catchments in the Lake Dianchi Basin, and estimates of NANI between two methods have an average difference of 30% on catchments basis while a smaller difference (15%) was observed on the whole Lake Dianchi Basin basis. The riverine N export has stronger linear relationship with NANI computed by land use-weighting method, which we believe is more reliable. Overall, nitrogen inputs assessed by the NANI approach for the Lake Dianchi Basin are 9900 kg N km-2 yr-1, ranging from 6600 to 28 000 kg N km-2 yr-1 among the 15 catchments. Synthetic N fertilizer is the largest component of NANI in most subwatersheds. On average, riverine flux of nitrogen in catchments of the Lake Dianchi Basin averages 83% of NANI, far higher than generally observed in North America and Europe. Saturated N sinks and limited capacity for denitrification in rivers may be responsible for this high percent of riverine N export. A negative intercept observed in the linear relationship between NANI and riverine N export suggests the influence of pollution control measures on N flux in small watershed. The NANI methodology should be applicable in small watersheds when sufficiently detailed data are available to estimate its components.

Gao, W.; Howarth, R. W.; Hong, B.; Swaney, D. P.; Guo, H. C.

2014-03-01

302

Long-term annual groundwater storage trends in Australian catchments  

NASA Astrophysics Data System (ADS)

The period of direct groundwater storage measurements is often too short to allow reliable inferences of groundwater storage trends at catchment scales. However, as groundwater storage sustains low flows in catchments during dry periods, groundwater storage can also be estimated indirectly from daily streamflow based on hydraulic groundwater theory; this idea was applied herein to 17 selected Australian catchments to examine their long-term (half a century or longer) groundwater storage trends. On average, over past 45 years, groundwater storage exhibited negative trends in all the selected catchments, except in the Katherine River catchment located in the Northern Territory. These negative trends persisted over longer periods, close to 100 years in some catchments and the strongest decreasing trend of 0.241 mm per year was observed in the Barron River catchment in New South Wales. However, groundwater storage exhibited different trends over the different shorter periods. Thus, while during the period of 1997-2007, 15 out of the 17 catchments showed negative trends in groundwater storage, during the period of 1980-2000, 12 out of the 17 catchments exhibited positive trends in groundwater storage; this underscores the fact that record lengths of one or even two decades are inadequate to derive meaningful trends. Strong consistencies in the trends exist across most catchments, indicating that groundwater storage is affected by large-scale climate factors.

Zhang, Lu; Brutsaert, Wilfried; Crosbie, Russell; Potter, Nick

2014-12-01

303

Quantitative Generalizations for Catchment Sediment Yield Following Plantation Logging  

NASA Astrophysics Data System (ADS)

While there is a reasonably clear qualitative understanding of the impact of forest plantations on sediment yield, there is a lack of quantitative generalizations. Such generalizations would be helpful for estimating the impacts of proposed forestry operations and would aid the spread of knowledge amongst both relevant professionals and new students. This study therefore analyzed data from the literature to determine the extent to which quantitative statements can be established. The research was restricted to the impact of plantation logging on catchment sediment yield as a function of ground disturbance in the years immediately following logging, in temperate countries, and does not consider landslides consequent upon tree root decay. Twelve paired catchment studies incorporating pre- and post-logging measurements of sediment yield were identified, resulting in forty-three test catchments (including 14 control catchments). Analysis yielded the following principal conclusions: 1) Logging generally provokes maximum annual sediment yields of less than a few hundred t km-2 yr-1; best management practice can reduce this below 100 t km-2 yr-1. 2) At both the annual and event scales, the sediment yield excess of a logged catchment over a control catchment is within one order of magnitude, except with severe ground disturbance. 3) There is no apparent relationship between sediment yield impact and the proportion of catchment logged. The effect depends on which part of the catchment is altered and on its connectivity to the stream network. 4) The majority of catchments delivered their maximum sediment yield in the first two years after logging. The logging impacts were classified in terms of the absolute values of specific sediment yield, the values relative to those in the control catchments for the same period and the values relative both to the control catchment and the pre-logging period. Most studies have been for small catchments (< 10 km2) and temperate regions; the impact at large catchment scales and in tropical regions requires further research.

Bathurst, James; Iroume, Andres

2014-05-01

304

Attributes for NHDPlus Catchments (Version 1.1)for the Conterminous United States: Contact Time, 2002  

USGS Publications Warehouse

This data set represents the average contact time, in units of days, compiled for every catchment of NHDPlus for the conterminous United States. Contact time, as described in Wolock and others (1989), is the baseflow residence time in the subsurface. The source data set was the U.S. Geological Survey's (USGS) 1-kilometer grid for the conterminous United States (D.M. Wolock, U.S. Geological Survey, written commun., 2008). The grid was created using a method described by Wolock and others (1997a; see equation 3). In the source data set, the contact time was estimated from 1-kilometer resolution elevation data (Verdin and Greenlee, 1996 ) and STATSGO soil characteristics (Wolock, 1997b). The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States. The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, contains NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus Production Units 4, 5, 7 and 9. MRB4, covering the Missouri River basins, contains NHDPlus Production Units 10-lower and 10-upper. MRB5, covering the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins, contains NHDPlus Production Units 8, 11 and 12. MRB6, covering the Rio Grande, Colorado and Great Basin River basins, contains NHDPlus Production Units 13, 14, 15 and 16. MRB7, covering the Pacific Northwest River basins, contains NHDPlus Production Unit 17. MRB8, covering California River basins, contains NHDPlus Production Unit 18.

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

305

Estimation of predictive hydrologic uncertainty using quantile regression and UNEEC methods and their comparison on contrasting catchments  

NASA Astrophysics Data System (ADS)

In operational hydrology, estimation of predictive uncertainty of hydrological models used for flood modelling is essential for risk based decision making for flood warning and emergency management. In the literature, there exists a variety of methods analyzing and predicting uncertainty. However, case studies comparing performance of these methods, most particularly predictive uncertainty methods, are limited. This paper focuses on two predictive uncertainty methods that differ in their methodological complexity: quantile regression (QR) and UNcertainty Estimation based on local Errors and Clustering (UNEEC), aiming at identifying possible advantages and disadvantages of these methods (both estimating residual uncertainty) based on their comparative performance. We test these two methods on several catchments (from UK) that vary in its hydrological characteristics and models. Special attention is given to the errors for high flow/water level conditions. Furthermore, normality of model residuals is discussed in view of clustering approach employed within the framework of UNEEC method. It is found that basin lag time and forecast lead time have great impact on quantification of uncertainty (in the form of two quantiles) and achievement of normality in model residuals' distribution. In general, uncertainty analysis results from different case studies indicate that both methods give similar results. However, it is also shown that UNEEC method provides better performance than QR for small catchments with changing hydrological dynamics, i.e. rapid response catchments. We recommend that more case studies of catchments from regions of distinct hydrologic behaviour, with diverse climatic conditions, and having various hydrological features be tested.

Dogulu, N.; López López, P.; Solomatine, D. P.; Weerts, A. H.; Shrestha, D. L.

2014-09-01

306

Influences on the establishment and dominance of vegetation in stormwater infiltration basins.  

PubMed

Infiltration basins are widely used in urban environments as a technique for managing and reducing the volume of stormwater. These basins can be spontaneously colonized by wild plants, which can be used as bioindicators of edaphic characteristics. As the basins are anthropogenic environments, the description of plant biodiversity allows the determination of which species colonize such environments and identification of the relationships between plants, basin type and operation. Nineteen infiltration basins were selected according to their catchment types (industrial, urban, agricultural). The dominant species were identified and sampled. Rumex sp., Taraxacum sp. and Artemisia sp. are the three types most represented (88, 61 and 55% respectively of the basins studied). Their families and their respective orders are those most commonly found (Caryophyllales, Asterales and Polygonaceae, Asteraceae). Poaceae is the family grouping with the largest number of different species (11). Although each species occupies only 1 or 2 basins, plants of this family occupy 61% of the basins. Although the catchment characteristics of the 19 basins do not play a direct role in the diversity of plant families, they can influence the presence or absence of certain species. Thus, these plants can be used as bio-indicators of basin soil and operating characteristics, such as sediment depths, inundation frequency and duration. PMID:24355843

Bedell, J-P; Mourier, B; Provot, J; Winiarski, T

2013-01-01

307

Examination of the Relationship Between Plot Scale Soil Properties and Catchment Scale Streamflow Recession Properties  

NASA Astrophysics Data System (ADS)

This work explores the empirical relationship between streamflow recession data from USGS stream gauges and high-resolution SSURGO soil data. The exploration of connections between streamflow recession and soil properties tests the general hypothesis that a relationship exists between plot scale soils data integrated across a catchment and catchment scale streamflow recession parameters. A dataset has been assembled using USGS HCDN watersheds for which SSURGO data is available across the continental United States. Tague and Grant (2004) have shown a linear relationship between streamflow recession parameters and a geologic classification based on the age of the underlying volcanic bedrock for Cascade streams in Oregon. Using a similar approach at a national scale, the research presented is aimed at improving the understanding of streamflow generation processes in different watersheds as well as the implications of using a priori parameters developed with high resolution soil data for distributed hydrologic modeling and prediction in ungauged basins. Watershed specific results elucidate the dominant factors controlling the hydrologic response in the different watersheds, such as geology (as a function of soil properties), slope/elevation, and soil properties identify landscape types. Overall results show that there is clustering of streamflow recession parameters based on regional climate and topography. References [1] Tague, C. and G.E. Grant, (2004), A Geological Framework for Interpreting the Low-Flow Regimes of Cascade Streams, Willamette River Basin, Oregon, Water Resources Research, 40(4)

Bandaragoda, C.; Tarboton, D.

2006-05-01

308

Assessment of catchment scale connectivity in different catchments using measured suspended sediment output  

NASA Astrophysics Data System (ADS)

Recent developments in hydrology and geomorphology include the connectivity principle, which describes how different elements in a landscape are connected and how water and matter moves between these elements. So far, studies on connectivity have been mainly of a conceptual nature and have been done on a small scale, while studies that map, quantitatively establish relations, and model water and sediment transport in connectivity are rare. In this study we established a relation between change in connectivity within four catchments and the time of year by using suspended sediment data. The data were collected for four catchments in Navarra, Spain of which two catchments are dominated by forest and pasture, while the other two catchments are dominated by agriculture and have no forest. Data were collected during a 13 year period; 4 samples were taken a day at 6 hour intervals which were mixed to obtain a daily average suspended sediment concentration. This was then converted into daily suspended sediment output using the measured total daily discharge. The effect of precipitation on the sediment output data was minimized by using an antecedent precipitation index (API), which consists of the precipitation of the current day added by the precipitation of the previous 14 days, where the influence of the previous days decays exponentially with time. The daily total suspended sediment output was divided by the API, to obtain a measure for sediment output independent of precipitation. This sediment output then serves as a measure for the connectivity within the catchment. The connectivity of the four catchments throughout the years will be compared to each other and we hypothesise that the two catchments dominated by forests and pastures will change only slightly throughout the year, whereas we expect to see large differences in connectivity in the two agricultural catchments. The agricultural catchments are likely to display a highly varying connectivity throughout the seasons due to changes in vegetation cover of the fields throughout the year, whereas daily variations will likely be small due to a slowly changing connectivity.

Masselink, Rens; Keesstra, Saskia; Seeger, Manuel

2014-05-01

309

Collaborative Catchment-Scale Water Quality Management using Integrated Wireless Sensor Networks  

NASA Astrophysics Data System (ADS)

Electronics and Computer Science, University of Southampton, United Kingdom Summary The challenge of improving water quality (WQ) is a growing global concern [1]. Poor WQ is mainly attributed to poor water management and outdated agricultural activities. We propose that collaborative sensor networks spread across an entire catchment can allow cooperation among individual activities for integrated WQ monitoring and management. We show that sharing information on critical parameters among networks of water bodies and farms can enable identification and quantification of the contaminant sources, enabling better decision making for agricultural practices and thereby reducing contaminants fluxes. Motivation and results Nutrient losses from land to water have accelerated due to agricultural and urban pursuits [2]. In many cases, the application of fertiliser can be reduced by 30-50% without any loss of yield [3]. Thus information about nutrient levels and trends around the farm can improve agricultural practices and thereby reduce water contamination. The use of sensor networks for monitoring WQ in a catchment is in its infancy, but more applications are being tested [4]. However, these are focussed on local requirements and are mostly limited to water bodies. They have yet to explore the use of this technology for catchment-scale monitoring and management decisions, in an autonomous and dynamic manner. For effective and integrated WQ management, we propose a system that utilises local monitoring networks across a catchment, with provision for collaborative information sharing. This system of networks shares information about critical events, such as rain or flooding. Higher-level applications make use of this information to inform decisions about nutrient management, improving the quality of monitoring through the provision of richer datasets of catchment information to local networks. In the full paper, we present example scenarios and analyse how the benefits of collaborative information sharing can have a direct influence on agricultural practice. We apply a nutrient management scheme to a model of an example catchment with several individual networks. The networks are able to correlate catchment events to events within their zone of influence, allowing them to adapt their monitoring and control strategy in light of wider changes across the catchment. Results indicate that this can lead to significant reductions in nutrient losses (up to 50%) and better reutilization of nutrients amongst farms, having a positive impact on catchment scale water quality and fertilizer costs. 1. EC, E.C., Directive 2000/60/EC establishing a framework for Community action in the field of water policy, 2000. 2. Rivers, M., K. Smettem, and P. Davies. Estimating future scenarios for farm-watershed nutrient fluxes using dynamic simulation modelling-Can on-farm BMPs really do the job at the watershed scale? in Proc.29th Int.Conf System Dynamics Society, 2011. 2010. Washington 3. Liu, C., et al., On-farm evaluation of winter wheat yield response to residual soil nitrate-N in North China Plain. Agronomy Journal, 2008. 100(6): p. 1527-1534. 4. Kotamäki, N., et al., Wireless in-situ sensor network for agriculture and water monitoring on a river basin scale in Southern Finland: Evaluation from a data user's perspective. Sensors, 2009. 9(4): p. 2862-2883.

Zia, Huma; Harris, Nick; Merrett, Geoff

2013-04-01

310

A fingerprinting mixing model approach to generate uniformly representative solutions for distributed contributions of sediment sources in a Pyrenean drainage basin  

NASA Astrophysics Data System (ADS)

Spanish Pyrenean reservoirs are under pressure from high sediment yields in contributing catchments. Sediment fingerprinting approaches offer potential to quantify the contribution of different sediment sources, evaluate catchment erosion dynamics and develop management plans to tackle the reservoir siltation problems. The drainage basin of the Barasona reservoir (1509 km2), located in the Central Spanish Pyrenees, is an alpine-prealpine agroforest basin supplying sediments to the reservoir at an annual rate of around 350 t km-2 with implications for reservoir longevity. The climate is mountain type, wet and cold, with both Atlantic and Mediterranean influences. Steep slopes and the presence of deep and narrow gorges favour rapid runoff and large floods. The ability of geochemical fingerprint properties to discriminate between the sediment sources was investigated by conducting the nonparametric Kruskal-Wallis H-test and a stepwise discriminant function analysis (minimization of Wilk's lambda). This standard procedure selects potential fingerprinting properties as optimum composite fingerprint to characterize and discriminate between sediment sources to the reservoir. Then the contribution of each potential sediment source was assessed by applying a Monte Carlo mixing model to obtain source proportions for the Barasona reservoir sediment samples. The Monte Carlo mixing model was written in C programming language and designed to deliver a user-defined number possible solutions. A Combinatorial Principals method was used to identify the most probable solution with associated uncertainty based on source variability. The unique solution for each sample was characterized by the mean value and the standard deviation of the generated solutions and the lower goodness of fit value applied. This method is argued to guarantee a similar set of representative solutions in all unmixing cases based on likelihood of occurrence. Soil samples for the different potential sediment sources of the drainage basin were compared with samples from the reservoir using a range of different fingerprinting properties (i.e. mass activities of environmental radionuclides, elemental composition and magnetic susceptibility) analyzed in the < 63 ?m sediment fraction. In this case, the 100 best results from 106 generated iterations were selected obtaining a goodness of fit higher than 0.76. The preliminary results using this new data processing methodology for samples collected in the reservoir allowed us to identify cultivated fields and badlands as main potential sources of sediments to the reservoir. These findings support the appropriate use of the fingerprinting methodology in a Spanish Pyrenees basin, which will enable us to better understand the basin sediment production of the Barasona reservoir.

Palazón, Leticia; Gaspar, Leticia; Latorre, Borja; Blake, Will; Navas, Ana

2014-05-01

311

Land use control of nitrate export behavior across catchments  

NASA Astrophysics Data System (ADS)

Nutrient exports from catchments and their temporal and spatial variability significantly affect downstream water quality and ecosystem health. There is hence a need to better understand and classify catchment nutrient export dynamics in order to reproduce catchment functions (such as nutrient mobilization and retention) and predict the response of these functions to changing boundary conditions. However, the complexity of catchment structure and the multitude of the processes involved challenge this objective. One approach to meet this challenge is a top-down, data-driven analysis of integrated catchment responses, such as discharge and solute concentration time series. For top-down analysis, different catchments are compared to identify key variables governing catchment response. We conducted a multi-catchment study applying top-down methods to analyze nitrate concentration and discharge time series from streams draining nine catchments in central Germany. The studied catchments, ranging from "pristine" mountains to agriculturally-managed lowlands, span gradients in land use, geology, and climatic conditions. We hypothesized that land use type is the main control on stream nitrate concentrations and catchment export behaviour, with more chemostatic export behaviour occurring in catchments with higher percentages of agricultural land use due to the presence of large nitrate stocks that effectively function as an unlimited nitrate storage. Consistent with this hypothesis we found that median nitrate concentrations were positively correlated with the percentage of agricultural land use in the different catchments despite differences in catchment climatic and geological conditions. Magnitude and direction of concentration-discharge relationship was evaluated using the slope b of the linear regression of log nitrate concentrations vs. log discharge as a metric for export behaviour. All catchments exhibited a positive slope b indicating concentrations increase with increasing discharge. The slope b was positively correlated with the percentage of agricultural land being artificially drained, which suggested that a higher share of drained agricultural land within the catchments results in a more dynamic export behaviour. Thus, a high percentage of agricultural land use, and subsequent higher nitrate input and storage, does not necessarily lead to chemostatic export conditions. While median concentrations were a function of agricultural land use, concentration dynamics and export behaviour were controlled by the presence of artificial drainage as the dominant input pathway of nitrate to surface waters. These results illustrate that it is feasible to use a multi-catchment top-down analysis to evaluate both dominant controls of nutrient export and the importance of land management on nutrient dynamics in the receiving surface waters.

Musolff, Andreas; Schmidt, Christian; Selle, Benny; Fleckenstein, Jan H.

2014-05-01

312

Similarity and scale in catchment storm response  

NASA Technical Reports Server (NTRS)

Until recently, very little progress had been made in understanding the relationship between small-scale variability of topography, soil, and rainfalls and the storm response seen at the catchment scale. The work reviewed here represents the first attempt at a systematic theoretical framework for such understanding in the context of surface runoff generation by different processes. The parameterization of hydrological processes over a range of scales is examined, and the concept of the 'representative elementary area' (REA) is introduced. The REA is a fundamental scale for catchment modeling at which continuum assumptions can be applied for the spatially variable controls and parameters, and spatial patterns no longer have to be considered explicitly. The investigation of scale leads into the concept of hydrologic similarity in which the effects of the environmental controls on runoff generation and flood frequency response be investigated independently of catchment scale. The paper reviews the authors' initial results and hopefully will motivate others to also investigate the issues of hydrologic scale and similarity.

Wood, Eric F.; Sivapalan, Murugesu; Beven, Keith

1993-01-01

313

Chemical weathering and runoff chemistry in a steep headwater catchment  

Microsoft Academic Search

We present here deductions about the location, rate, and mechanisms of chemical weathering in a small catchment based on a catchment-scale sprinkling experiment. In this experiment demineralized water was applied at an approximately steady rate in the CB1 catchment in the Oregon Coast Range to reach and maintain a quasi-steady discharge for a period of 4 days. Because of nearly

Suzanne Prestrud Anderson; William E. Dietrich

2001-01-01

314

Investigation of water pollution in the Yalvac basin into Egirdir Lake, Turkey  

Microsoft Academic Search

The aim of this study is to understand the effects of pollution of anthropogenic origin on water quality in Yalvac Basin,\\u000a part of the Egirdir Lake catchment. Surface discharge from the basin to the lake is 63 m3\\/year and underground discharge is 114 m3\\/year. Possible water pollution is categorized into domestic, industrial and agricultural origin. Domestic and industrial\\u000a wastewaters, including effluents from

I. Iskender Soyaslan; Remzi Karagüzel

2008-01-01

315

Geochemical techniques on contaminated sediments-river basin view  

Microsoft Academic Search

The big flood in the upper Elbe River catchment area has revealed a wide spectrum of problems with contaminated sediments.\\u000a So far, an effective strategy for managing contaminated sediments on a river basin scale is still missing and it seems that\\u000a not much has been learned from the lessons received during the last decade.\\u000a \\u000a In the following overview, special emphasis

Ulrich Förstner

2003-01-01

316

Flood design recipes vs. reality: can predictions for ungauged basins be trusted?  

NASA Astrophysics Data System (ADS)

Despite the great scientific and technological advances in flood hydrology, everyday engineering practices still follow simplistic approaches, such as the rational formula and the SCS-CN method combined with the unit hydrograph theory that are easy to formally implement in ungauged areas. In general, these "recipes" have been developed many decades ago, based on field data from few experimental catchments. However, many of them have been neither updated nor validated across all hydroclimatic and geomorphological conditions. This has an obvious impact on the quality and reliability of hydrological studies, and, consequently, on the safety and cost of the related flood protection works. Preliminary results, based on historical flood data from Cyprus and Greece, indicate that a substantial revision of many aspects of flood engineering procedures is required, including the regionalization formulas as well as the modelling concepts themselves. In order to provide a consistent design framework and to ensure realistic predictions of the flood risk (a key issue of the 2007/60/EU Directive) in ungauged basins, it is necessary to rethink the current engineering practices. In this vein, the collection of reliable hydrological data would be essential for re-evaluating the existing "recipes", taking into account local peculiarities, and for updating the modelling methodologies as needed.

Efstratiadis, A.; Koussis, A. D.; Koutsoyiannis, D.; Mamassis, N.

2013-12-01

317

Evolution of a trench-slope basin within the Cascadia subduction margin: the Neogene Humboldt Basin, California  

USGS Publications Warehouse

The Neogene Humboldt (Eel River) Basin is located along the north-eastern margin of the Pacific Ocean within the Cascadia subduction zone. This sedimentary basin originated near the base of the accretionary prism in post-Eocene time. Subduction processes since that time have elevated strata in the south-eastern portion of the basin above sea level. High-resolution chronostratigraphic data from the onshore portion of the Humboldt Basin enable correlation of time-equivalent lithofacies across the palaeomargin, reconstruction of slope-basin evolution, and preliminary delineation of climatic and tectonic influence on lithological variation. -from Author

McCrory, P.A.

1995-01-01

318

Importance of diffuse pollution control in the Patzcuaro Lake Basin in Mexico  

Microsoft Academic Search

In the catchment area of the Lake Patzcuaro in Central Mexico (933 km2) the apportionments of erosion, sediment, nutrients and pathogen coming from thirteen micro basins were estimated with the purpose of identifying critical areas in which best management practices need to be implemented in order to reduce their contribution to the lake pollution and eutrophication. The ArcView Generalized Watershed

Marco Mijangos Carro; Jorge Izurieta Dávila; Antonieta Gómez Balandra; Rubén Hernández López; Rubén Huerto Delgadillo; Javier Sánchez Chávez; Luís Bravo Inclán

2008-01-01

319

Metaphor in Natural Resource Gaming: Insights from the RIVER BASIN GAME  

ERIC Educational Resources Information Center

The RIVER BASIN GAME is a dialogue tool for decision makers and water users tested in Tanzania and Nigeria. It comprises a physical representation of a river catchment. A central channel flows between an upper watershed and a downstream wetland and has on it several intakes into irrigation systems. Glass marbles, representing water, roll down the…

Lankford, Bruce; Watson, Drennan

2007-01-01

320

Quantifying transient erosion of orogens with detrital thermochronology from syntectonic basin deposits  

E-print Network

. In simulations with transient erosion, the estimation of erosion rates from a detrital record using assumptionQuantifying transient erosion of orogens with detrital thermochronology from syntectonic basin, illustrates how the transient catchment averaged erosion history can be quantified with detrital

Rahl, Jeffrey M.