Science.gov

Sample records for affected rivers due

  1. Morphological Changes of River Due To Constructed Structures Case study : Sephidrood river

    NASA Astrophysics Data System (ADS)

    Motiee, H.; Darakhani, J.

    2003-04-01

    Permanent rivers will reach to their steady equilibrium with the adjacent nature after long time. This stability will survive untill human being interfere it, which in turn may result in a chaos condition of the river. Severe changes in riverbed as well as riverbanks may occur due to different reasons such as economical development, population growth, need for more sand and construction materials and sediment removal from reservoirs. Main factors governing the river morphology are as follows: 1. Obtaining sand and clay from river 2. Construction of structures on the river 3. Intruding the river banks Sefid-Rud is one of the most important rivers, which flows in north of IRAN in Gilan province. It passes through the Gilan great watershed and reaches to the Caspian Sea in the North of the country. The catchment with an area of 59400 km2 is one of the most fertile basins in the world and the river plays an important role in economic improvement of the region. Its average annual discharge is 125 cms and the river length is 765 km, which extends from Zagross ranges to the Caspian Sea. During 1954 to 1960 a large dam was constructed some 125 km upstream of its enlet to the sea. It is a multipurpose, 106-m high buttress dam, which has significant impacts on the river morphology. Major purposes for construction of Sefid-Rud reservoir dam are: - Flood control in order to prevent the scouring of Sefid-Rud river banks - Full supply of irrigation water demands for downstream rice-cultivated lands - Hydropower energy production The Sefid-Rud River has reached to its stable condition due to different reasons such as geological and alluvial formations, hydrological characteristics of the basin as well as hydraulic conditions of the river. But variable conditions of some of these factors have resulted in a sudden change of river morphology, especially in some reaches. Normally, the river reactions to external natural variations and/or intrusion to river geometry, exhibit as

  2. Global-scale analysis of river flow alterations due to water withdrawals and reservoirs

    NASA Astrophysics Data System (ADS)

    Döll, P.; Fiedler, K.; Zhang, J.

    2009-12-01

    Global-scale information on natural river flows and anthropogenic river flow alterations is required to identify areas where aqueous ecosystems are expected to be strongly degraded. Such information can support the identification of environmental flow guidelines and a sustainable water management that balances the water demands of humans and ecosystems. This study presents the first global assessment of the anthropogenic alteration of river flow regimes, in particular of flow variability, by water withdrawals and dams/reservoirs. Six ecologically relevant flow indicators were quantified using an improved version of the global water model WaterGAP. WaterGAP simulated, with a spatial resolution of 0.5 degree, river discharge as affected by human water withdrawals and dams around the year 2000, as well as naturalized discharge without this type of human interference. Compared to naturalized conditions, long-term average global discharge into oceans and internal sinks has decreased by 2.7% due to water withdrawals, and by 0.8% due to dams. Mainly due to irrigation, long-term average river discharge and statistical low flow Q90 (monthly river discharge that is exceeded in 9 out of 10 months) have decreased by more than 10% on one sixth and one quarter of the global land area (excluding Antarctica and Greenland), respectively. Q90 has increased significantly on only 5% of the land area, downstream of reservoirs. Due to both water withdrawals and reservoirs, seasonal flow amplitude has decreased significantly on one sixth of the land area, while interannual variability has increased on one quarter of the land area mainly due to irrigation. It has decreased on only 8% of the land area, in areas downstream of reservoirs where consumptive water use is low. The impact of reservoirs is likely underestimated by our study as small reservoirs are not taken into account. Areas most affected by anthropogenic river flow alterations are the Western and Central USA, Mexico, the

  3. Acidification of floodplains due to river level decline during drought.

    PubMed

    Mosley, Luke M; Palmer, David; Leyden, Emily; Cook, Freeman; Zammit, Benjamin; Shand, Paul; Baker, Andrew; W Fitzpatrick, Rob

    2014-06-01

    A severe drought from 2007 to 2010 resulted in the lowest river levels (1.75 m decline from average) in over 90 years of records at the end of the Murray-Darling Basin in South Australia. Due to the low river level and inability to apply irrigation, the groundwater depth on the adjacent agricultural flood plain also declined substantially (1-1.5 m) and the alluvial clay subsoils dried and cracked. Sulfidic material (pH>4, predominantly in the form of pyrite, FeS2) in these subsoils oxidised to form sulfuric material (pH<4) over an estimated 3300 ha on 13 floodplains. Much of the acidity in the deeply cracked contaminated soil layers was in available form (in pore water and on cation exchange sites), with some layers having retained acidity (iron oxyhydroxysulfate mineral jarosite). Post drought, the rapid raising of surface and ground water levels mobilised acidity in acid sulfate soil profiles to the floodplain drainage channels and this was transported back to the river via pumping. The drainage water exhibited low pH (2-5) with high soluble metal (Al, Co, Mn, Fe, Mn, Ni, and Zn) concentrations, in exceedance of guidelines for ecosystem protection. Irrigation increased the short-term transport of acidity, however loads were generally greater in the non-irrigation (winter) season when rainfall is highest (0.0026 tonnes acidity/ha/day) than in the irrigation (spring-summer) season (0.0013 tonnes acidity/ha/day). Measured reductions in groundwater acidity and increases in pH have been observed over time but severe acidification persisted in floodplain sediments and waters for over two years post-drought. Results from 2-dimensional modelling of the river-floodplain hydrological processes were consistent with field measurements during the drying phase and illustrated how the declining river levels led to floodplain acidification. A modelled management scenario demonstrated how river level stabilisation and limited irrigation could have prevented, or greatly lessened

  4. Acidification of floodplains due to river level decline during drought.

    PubMed

    Mosley, Luke M; Palmer, David; Leyden, Emily; Cook, Freeman; Zammit, Benjamin; Shand, Paul; Baker, Andrew; W Fitzpatrick, Rob

    2014-06-01

    A severe drought from 2007 to 2010 resulted in the lowest river levels (1.75 m decline from average) in over 90 years of records at the end of the Murray-Darling Basin in South Australia. Due to the low river level and inability to apply irrigation, the groundwater depth on the adjacent agricultural flood plain also declined substantially (1-1.5 m) and the alluvial clay subsoils dried and cracked. Sulfidic material (pH>4, predominantly in the form of pyrite, FeS2) in these subsoils oxidised to form sulfuric material (pH<4) over an estimated 3300 ha on 13 floodplains. Much of the acidity in the deeply cracked contaminated soil layers was in available form (in pore water and on cation exchange sites), with some layers having retained acidity (iron oxyhydroxysulfate mineral jarosite). Post drought, the rapid raising of surface and ground water levels mobilised acidity in acid sulfate soil profiles to the floodplain drainage channels and this was transported back to the river via pumping. The drainage water exhibited low pH (2-5) with high soluble metal (Al, Co, Mn, Fe, Mn, Ni, and Zn) concentrations, in exceedance of guidelines for ecosystem protection. Irrigation increased the short-term transport of acidity, however loads were generally greater in the non-irrigation (winter) season when rainfall is highest (0.0026 tonnes acidity/ha/day) than in the irrigation (spring-summer) season (0.0013 tonnes acidity/ha/day). Measured reductions in groundwater acidity and increases in pH have been observed over time but severe acidification persisted in floodplain sediments and waters for over two years post-drought. Results from 2-dimensional modelling of the river-floodplain hydrological processes were consistent with field measurements during the drying phase and illustrated how the declining river levels led to floodplain acidification. A modelled management scenario demonstrated how river level stabilisation and limited irrigation could have prevented, or greatly lessened

  5. Acidification of floodplains due to river level decline during drought

    NASA Astrophysics Data System (ADS)

    Mosley, Luke M.; Palmer, David; Leyden, Emily; Cook, Freeman; Zammit, Benjamin; Shand, Paul; Baker, Andrew; W. Fitzpatrick, Rob

    2014-06-01

    A severe drought from 2007 to 2010 resulted in the lowest river levels (1.75 m decline from average) in over 90 years of records at the end of the Murray-Darling Basin in South Australia. Due to the low river level and inability to apply irrigation, the groundwater depth on the adjacent agricultural flood plain also declined substantially (1-1.5 m) and the alluvial clay subsoils dried and cracked. Sulfidic material (pH > 4, predominantly in the form of pyrite, FeS2) in these subsoils oxidised to form sulfuric material (pH < 4) over an estimated 3300 ha on 13 floodplains. Much of the acidity in the deeply cracked contaminated soil layers was in available form (in pore water and on cation exchange sites), with some layers having retained acidity (iron oxyhydroxysulfate mineral jarosite). Post drought, the rapid raising of surface and ground water levels mobilised acidity in acid sulfate soil profiles to the floodplain drainage channels and this was transported back to the river via pumping. The drainage water exhibited low pH (2-5) with high soluble metal (Al, Co, Mn, Fe, Mn, Ni, and Zn) concentrations, in exceedance of guidelines for ecosystem protection. Irrigation increased the short-term transport of acidity, however loads were generally greater in the non-irrigation (winter) season when rainfall is highest (0.0026 tonnes acidity/ha/day) than in the irrigation (spring-summer) season (0.0013 tonnes acidity/ha/day). Measured reductions in groundwater acidity and increases in pH have been observed over time but severe acidification persisted in floodplain sediments and waters for over two years post-drought. Results from 2-dimensional modelling of the river-floodplain hydrological processes were consistent with field measurements during the drying phase and illustrated how the declining river levels led to floodplain acidification. A modelled management scenario demonstrated how river level stabilisation and limited irrigation could have prevented, or greatly

  6. Global-scale analysis of river flow alterations due to water withdrawals and reservoirs

    NASA Astrophysics Data System (ADS)

    Döll, P.; Fiedler, K.; Zhang, J.

    2009-07-01

    Global-scale information on natural river flows and anthropogenic river flow alterations is required to identify areas where aqueous ecosystems are expected to be strongly degraded. Such information can support the identification of environmental flow guidelines and a sustainable water management that balances the water demands of humans and ecosystems. This study presents the first global assessment of the anthropogenic alteration of river flow regimes by water withdrawals and dams, focusing in particular on the change of flow variability. Six ecologically relevant flow indicators were quantified using an improved version of the global water model WaterGAP. WaterGAP simulated, with a spatial resolution of 0.5 degree, river discharge as affected by human water withdrawals and dams, as well as naturalized discharge without this type of human interference. Mainly due to irrigation, long-term average river discharge and statistical low flow Q90 (monthly river discharge that is exceeded in 9 out of 10 months) have decreased by more than 10% on one sixth and one quarter of the global land area (excluding Antarctica and Greenland), respectively. Q90 has increased significantly on only 5% of the land area, downstream of reservoirs. Due to both water withdrawals and dams, seasonal flow amplitude has decreased significantly on one sixth of the land area, while interannual variability has increased on one quarter of the land area mainly due to irrigation. It has decreased on only 8% of the land area, in areas with little consumptive water use that are downstream of dams. Areas most affected by anthropogenic river flow alterations are the western and central USA, Mexico, the western coast of South America, the Mediterranean rim, Southern Africa, the semi-arid and arid countries of the Near East and Western Asia, Pakistan and India, Northern China and the Australian Murray-Darling Basin, as well as some Arctic rivers. Due to a large number of uncertainties related e.g. to the

  7. Reduction of livelihood risk for river bank erosion affected villagers

    NASA Astrophysics Data System (ADS)

    Majumder, S. Sen; Fox, D. M.; Chakrabari, S.; Bhandari, G.

    2014-12-01

    Bank erosion process of the Ganga River created a serious livelihood risk for the villagers situated on left bank of the river in Malda district of the State of West Bengal, India since last four decades. Due to the erosion of agriculture land by the river, most of the villagers having agriculture as their only means of livelihood became jobless suddenly. Presently they are living in a miserable condition. One of the main objectives of this paper is to find out an alternative means of livelihood for the victims to improve their miserable socio-economic condition. It has been found from field survey that some erosion affected villagers have started to live and practice agriculture temporarily on the riverine islands (large and stable since thirteen years) as these islands have very fertile soil. If the re-emerged land plots can again be demarcated on the newly formed islands and distributed among the landless people to practice agriculture over there, then it will be a useful alternative livelihood strategy for the victims. The demarcation of re-emerged plots can be achieved by georeferencing the cadastral maps and then overlaying the plots on the present river course. In the present study area geo-referencing process of the cadastral maps became a serious issue as the study area has been very dynamic in terms of land cover and land use. Most of the villages were lost into the river course. Thus the common permanent features, required for geo-referencing, shown in the cadastral maps (surveyed during 1954-1962) were not found in the present satellite images. The second important objective of the present study is to develop a proper methodology for geo-referencing the cadastral maps of this area. The Spatial Adjustment Transformation and Automatic Digitization tools of Arc GIS were used to prepare geo-referenced plot maps. In Projective Transformation method the geometrically corrected block maps having village boundaries were used as source file. Then the

  8. River channel morphology and hydraulics properties due to introduction of plant basket hydraulic structures for river channel management

    NASA Astrophysics Data System (ADS)

    Kałuża, Tomasz; Radecki-Pawlik, Artur; Plesiński, Karol; Walczak, Natalia; Szoszkiewicz, Krzysztof; Radecki-Pawlik, Bartosz

    2016-04-01

    In the present time integrated water management is directly connected with management and direct works in river channels themselves which are taking into account morphological processes in rivers and improve flow conditions. Our work focused on the hydraulic and hydrodynamic consequences upon the introduction of the concept of the improvement of the hydromorphological conditions of the Flinta River in a given reach following river channel management concept. Based on a comprehensive study of the hydromorphological state of the river, four sections were selected where restoration measures can efficiently improve river habitat conditions in the river. For each section a set of technical and biological measures were proposed and implemented in practice. One of the proposed solutions was to construct plant basket hydraulic structures (PBHS) within the river channel, which are essentially plant barriers working as sediment traps, changing river channel morphology and are in line with concepts of Water Framework Directive. These relatively small structures work as crested weirs and unquestionably change the channel morphology. Along our work we show the results of three-year long (2013-2015) systematic measurements that provided information on the morphological consequences of introducing such structures into a river channel. Our main conclusions are as follows: 1. Plant basket hydraulic structures cause changes in hydrodynamic conditions and result in sediment accumulation and the formation of river backwaters upstream and downstream the obstacle; 2. The introduced plant basket hydraulic structures cause plant debris accumulation which influences the hydrodynamic flow conditions; 3. The installation of plant basket hydraulic structures on the river bed changes flow pattern as well as flow hydrodynamic conditions causing river braiding process; 4. The erosion rate below the plant basket hydraulic structures is due to the hydraulic work conditions of the PBHS and its

  9. Reduced sediment transport in the Yellow River due to anthropogenic changes

    NASA Astrophysics Data System (ADS)

    Wang, Shuai; Fu, Bojie; Piao, Shilong; Lü, Yihe; Ciais, Philippe; Feng, Xiaoming; Wang, Yafeng

    2016-01-01

    The erosion, transport and redeposition of sediments shape the Earth’s surface, and affect the structure and function of ecosystems and society. The Yellow River was once the world’s largest carrier of fluvial sediment, but its sediment load has decreased by approximately 90% over the past 60 years. The decline in sediment load is due to changes in water discharge and sediment concentration, which are both influenced by regional climate change and human activities. Here we use an attribution approach to analyse 60 years of runoff and sediment load observations from the traverse of the Yellow River over China’s Loess Plateau -- the source of nearly 90% of its sediment load. We find that landscape engineering, terracing and the construction of check dams and reservoirs were the primary factors driving reduction in sediment load from the 1970s to 1990s, but large-scale vegetation restoration projects have also reduced soil erosion from the 1990s onwards. We suggest that, as the ability of existing dams and reservoirs to trap sediments declines in the future, erosion rates on the Loess Plateau will increasingly control the Yellow River’s sediment load.

  10. Does river restoration affect diurnal and seasonal changes to surface water quality? A study along the Thur River, Switzerland.

    PubMed

    Chittoor Viswanathan, Vidhya; Molson, John; Schirmer, Mario

    2015-11-01

    Changes in river water quality were investigated along the lower reach of the Thur River, Switzerland, following river restoration and a summer storm event. River restoration and hydrological storm events can each cause dramatic changes to water quality by affecting various bio-geochemical processes in the river, but have to date not been well documented, especially in combination. Evaluating the success of river restoration is often restricted in large catchments due to a lack of high frequency water quality data, which are needed for process understanding. These challenges were addressed in this study by measuring water quality parameters including dissolved oxygen (DO), temperature, pH, electrical conductivity (EC), nitrate and dissolved organic carbon (DOC) with a high temporal frequency (15 min-1h) over selected time scales. In addition, the stable isotopes of water (δD and δ(18)O-H2O) as well as those of nitrate (δ(15)N-NO3(-) and δ(18)O-NO3(-)) were measured to follow changes in water quality in response to the hydrological changes in the river. To compare the spatial distribution of pre- and post-restoration water quality, the sampling stations were chosen upstream and downstream of the restored section. The diurnal and seasonal changes were monitored by conducting 24-hour campaigns in three seasons (winter, summer and autumn) in 2012 and 2013. The amplitude of the diurnal changes of the various observed parameters showed significant seasonal and spatial variability. Biological processes--mainly photosynthesis and respiration--were found to be the major drivers of these diurnal cycles. During low flow in autumn, a reduction of nitrate (attributed to assimilation by autotrophs) in the pre-dawn period and a production of DOC during the daytime (attributed to photosynthesis) were observed downstream of the restored site. Further, a summer storm event was found to override the influence of these biological processes that control the diurnal changes. High

  11. Does river restoration affect diurnal and seasonal changes to surface water quality? A study along the Thur River, Switzerland.

    PubMed

    Chittoor Viswanathan, Vidhya; Molson, John; Schirmer, Mario

    2015-11-01

    Changes in river water quality were investigated along the lower reach of the Thur River, Switzerland, following river restoration and a summer storm event. River restoration and hydrological storm events can each cause dramatic changes to water quality by affecting various bio-geochemical processes in the river, but have to date not been well documented, especially in combination. Evaluating the success of river restoration is often restricted in large catchments due to a lack of high frequency water quality data, which are needed for process understanding. These challenges were addressed in this study by measuring water quality parameters including dissolved oxygen (DO), temperature, pH, electrical conductivity (EC), nitrate and dissolved organic carbon (DOC) with a high temporal frequency (15 min-1h) over selected time scales. In addition, the stable isotopes of water (δD and δ(18)O-H2O) as well as those of nitrate (δ(15)N-NO3(-) and δ(18)O-NO3(-)) were measured to follow changes in water quality in response to the hydrological changes in the river. To compare the spatial distribution of pre- and post-restoration water quality, the sampling stations were chosen upstream and downstream of the restored section. The diurnal and seasonal changes were monitored by conducting 24-hour campaigns in three seasons (winter, summer and autumn) in 2012 and 2013. The amplitude of the diurnal changes of the various observed parameters showed significant seasonal and spatial variability. Biological processes--mainly photosynthesis and respiration--were found to be the major drivers of these diurnal cycles. During low flow in autumn, a reduction of nitrate (attributed to assimilation by autotrophs) in the pre-dawn period and a production of DOC during the daytime (attributed to photosynthesis) were observed downstream of the restored site. Further, a summer storm event was found to override the influence of these biological processes that control the diurnal changes. High

  12. Man versus Rivers: the lost equilibrium of the Tisza River due to engineering works

    NASA Astrophysics Data System (ADS)

    Kiss, Timea; Fiala, Károly

    2016-04-01

    The direct and indirect human impacts alter the catchment and the channel characteristics, which will result in further hydro-morphological alterations of rivers. The modified fluvial environment will create new hydrological hazards for the society, so for the successful and sustainable hazard and risk management it is important to evaluate the equilibrium and sensitivity of rivers. The aim of the paper is to evaluate the hydrological and morphological effects of engineering works along the Tisza River, Hungary. Based on the trends of the different fluvial processes the equilibrium of the river will be evaluated to ground further engineering works. The Tisza River, was one of the first systematically regulated rivers in Europe. In the late 19th century artificial cut-offs were made, shortening the river by ca. 30%. The hydrology and the morphology of the Tisza adapted to this, as the channel became temporarily wider and deeper (by 20-25%). The cut-offs had an effect on the channel for ca. 60-70 years. Simultaneously, artificial levees were built, thus the overbank floodplain aggradation became more intensive (from 0.02-0.07 cm/y to 0.3-0.8 mm/y). The floodplain aggradation became higher by 2-4 times since 1970's, as the vegetation became denser. However, in the 21st c. the floodplain vegetation became so uncontrollably dense, that the pattern and rate of accumulation changed again, and now it is limited just to the banks. So the levee could be considered as continuous disturbing factor, besides, the unmanaged floodplain vegetation appeared as a new disturbing force accelerating the processes. In the 20th century revetments were constructed to stop the lateral migration of the channel. This resulted in channel distortion, as it became sharper and the cross-sectional area decreased by 28%. As revetments were constructed along ca. 51% of the channel, the meandering channel forms became replaced features characteristic in incising rivers, for example point

  13. Sele coastal plain flood risk due to wave storm and river flow interaction

    NASA Astrophysics Data System (ADS)

    Benassai, Guido; Aucelli, Pietro; Di Paola, Gianluigi; Della Morte, Renata; Cozzolino, Luca; Rizzo, Angela

    2016-04-01

    -critical simulation, the boundary condition is a known downstream WSE, in this case the elevated water level due to wave setup, wind setup and inverted barometer, while the upstream boundary condition consisted in WSE corresponding to river discharges associated to different return periods. The results of the simulations evidence, for the last 10 kilometers of the river, the burst of critical inundation scenarios even with moderate flow discharge, if associated with concurrent storm surge which increase the water level at the river mouth, obstructing normal flow discharge.

  14. Sediment transport due to extreme events: The Hudson River estuary after tropical storms Irene and Lee

    USGS Publications Warehouse

    Ralston, David K.; Warner, John C.; Geyer, W. Rockwell; Wall, Gary R.

    2013-01-01

    Tropical Storms Irene and Lee in 2011 produced intense precipitation and flooding in the U.S. Northeast, including the Hudson River watershed. Sediment input to the Hudson River was approximately 2.7 megaton, about 5 times the long-term annual average. Rather than the common assumption that sediment is predominantly trapped in the estuary, observations and model results indicate that approximately two thirds of the new sediment remained trapped in the tidal freshwater river more than 1 month after the storms and only about one fifth of the new sediment reached the saline estuary. High sediment concentrations were observed in the estuary, but the model results suggest that this was predominantly due to remobilization of bed sediment. Spatially localized deposits of new and remobilized sediment were consistent with longer term depositional records. The results indicate that tidal rivers can intercept (at least temporarily) delivery of terrigenous sediment to the marine environment during major flow events.

  15. The performance of the Hydromorphological Index of Diversity (HMID) in a hydropower affected meandering river

    NASA Astrophysics Data System (ADS)

    Stähly, Severin; Bourqui, Pierre; Franca, Mario J.; Robinson, Christopher; Schleiss, Anton J.

    2016-04-01

    More than half of the Swiss electricity is produced by hydropower. Large price fluctuations cause severe hydropeaking flow regimes due to corresponding production fluctuations, which undisputedly have a negative impact on aquatic biota. Water diversion due to dams on the other hand imposes downstream residual flow regimes. The absence of flood events and regular sediment supply disrupts sediment dynamics and disconnects floodplains, which are habitats of high value, from its main channel. The residual-flow controlled reach at the Sarine river in western Switzerland is the subject of the present study. The Sarine meanders strongly and the river reach under analysis has a bed incision of locally more than 100 m. Its incision provokes the isolation of the river which is consequently minimally touched by human structures and shows a natural geomorphology. Since the construction of a dam upstream this reach in 1948, aiming at the water abstraction to hydropower, vegetation could establish and the active floodplain decreased its area, as airborne images show. Nevertheless, it is classified as a floodplain of national importance and it has been under protection since 1992. It is supposed to be a valuable habitat for a wide range of organisms. The Hydromorphological Index of Diversity (HMID) is a simple tool for quantifying the habitat richness in a river reach, taking into account the mean values and the variation of water depth and flow velocity. For channelized rivers, HMID values from up to 5 are expected, while morphological pristine sites with a high spatial variability of water depth and velocity show values of 9 or higher. For the residual flow of the Sarine River, flow depth and velocity were measured using ADCP and ADV. The results are compared with a nearby natural reference river and the outcome of a 2D numerical simulation. Finally, the behaviour and limitations of the HMID, in a hydropower affected river, are discussed. In the close future an artificial flood

  16. Flow regulation and river fragmentation in large basins due to global dam development (Invited)

    NASA Astrophysics Data System (ADS)

    Grill, G. O.; Lehner, B.

    2013-12-01

    Dam construction has recently received new interest as an alternative and renewable source of energy, especially in developing countries, and as a means to provide water security in regions with naturally variable water flows. On the other hand, the negative effects from increased fragmentation of the world's large rivers through hydropower and irrigation dams is a matter of great concern for ecologists and conservationists. The main negative effects of dams result from their role as a barrier for migratory fish species, as well as the alteration of the natural flow regime owing to artificial water release schedules. While the trade-offs between these antagonistic effects are usually assessed locally by conducting environmental impact assessments at and in the vicinity of the construction site, the cumulative effects of multiple dams located in the same basin are generally neglected in such plans. To address the cumulative effects at the scale of large river networks, we developed a new impact assessment approach by combining state-of-the-art global scale hydrographic (HydroSHEDS) and hydrological models (WaterGAP) with a river routing scheme (HydroROUT). This combination enables modelers to simulate scenarios for historic, current and future conditions that allow for comparisons between the large river basins of the world. We derive indices that can describe the relative impact of individual and multiple dams regarding flow alteration and habitat fragmentation at a global scale. Our model also allows for the application of tailor-made weighting schemes to include information of eco-hydrological classifications, as well as species richness and diversity. Furthermore, we include natural barriers such as waterfalls, and examine their effect on river network connectivity. Results for the Greater Mekong Region show that ecosystem connectivity and flow alteration are most strongly affected by dams located at the mainstream rivers, particularly for basins where the main

  17. Trace metals in sediments of a Mediterranean estuary affected by human activities (Acheloos river estuary, Greece).

    PubMed

    Dassenakis, M; Degaita, A; Scoullos, M

    1995-05-19

    Trace metals were studied in the sediments of the ecologically, economically and scientifically important estuary of the Acheloos river, in western Greece. Human activities (dams, agriculture, traffic, etc.) influence the estuarine system of Acheloos and in combination with the hydrological, mineralogical and morphological characteristics of the estuary affect the chemical behaviour and the distribution patterns of trace metals in its sediments. The large scale disturbance of the system is imminent in the near future as it is planned to divert approximately 50% of the river water. A study of the distribution patterns of trace metals revealed that in the estuary there are zones with different metal levels. The concentrations of most metals (Al, Fe, Cu, Ni, Zn) are elevated in three of these zones (upstream, sill, seawards). A different behaviour was observed for Mn due to its association with carbonates that were observed in significant concentrations throughout the estuarine zone. A sequential extraction procedure, applied to the sediments, indicated low percentages of easily exchangeable metals, increased mobility of Cu and Zn and increased association of Ni, Cr and Fe with the aluminosilicate lattice. Although the river is not considered to be heavily polluted, some metals have shown an enrichment in the surface sediments as a result of general anthropogenic activities not derived from point sources.

  18. Are discontinuous rating curves in sand bedded rivers due to bedform transitions or bed scour?

    NASA Astrophysics Data System (ADS)

    Yousfi, Y. M.; Sklar, L. S.; Dawdy, D. R.

    2013-12-01

    Estimating discharge from flow stage in sand-bedded rivers is complicated by non-monotonic relationships between gauge height and discharge. These discontinuous rating curves have an enigmatic region where stage decreases while discharge increases, such that the same stage is apparently associated with two possible discharges. Previous work has shown that this can occur due to changes in bed configuration that reduce roughness and increase flow conveyance. An alternative explanation is that the increase in conveyance is due to enhanced bed scour and changes in cross-section geometry. Here we investigate these two hypotheses using discharge gauge measurements from the San Juan River at Shiprock, New Mexico. We focus on the snowmelt hydrograph of 1941, for which the gauge operator made a unique set of notations indicating the presence of sand boils and sand waves. We use these field observations to calibrate a site-specific model for the flow conditions that create dune, plane and anti-dune bed configurations. For each gauged discharge, we back-calculate cross-section average roughness coefficients and flow conveyance area. From these data we evaluate the relative contribution of changes in bed configuration and cross-section geometry to the observed discontinuities in the stage-discharge relationship. The outcome of this analysis will be useful in modeling flow, and reducing errors in estimating discharge, in large sand-bedded rivers.

  19. Long-term changes to flood conditions due to varying management strategies, Rock River, WI

    NASA Astrophysics Data System (ADS)

    Fredrick, K. C.

    2015-12-01

    The Rock River is a 300-mile tributary of the Mississippi River in southern Wisconsin. Its source is a protected migratory bird habitat called the Horicon National Wildlife Refuge. Below the refuge, the Rock River flows through mostly rural, agricultural areas, with wide floodplain of mixed land use. Between the dam at Horicon and a hydroelectric dam in Watertown, WI, lie the townships of Lebanon, Ashippun, and Ixonia. These rural townships boast productive agricultural lands of mostly corn, soybeans, and alfalfa. Large portions of their land are within the floodplain, underlain by vast expanses of outwash sands and gravels, glaciolacustrine deposits, and tills. Throughout the region, spring floods are common from snowmelt and spring rain. These annual floods may be exacerbated by frozen ground and slow infiltration, making it an accepted part of life for residents. Over the last 8 years, and possibly as many as 20, this segment of the Rock River has seen an increase in flooding both in periodicity and retention of flood waters. Due to the delicate habitat of the wildlife refuge and the commissioned hydroelectric installation at the upper dam in Watertown, the residents and local governments of the Lebanon/Ashippun/Ixonia segment of the river have mostly been left to their own devices to monitor and manage flood events. Lebanon Township has been recording water levels for several years. Recent events at the hydroelectric plant seem to indicate that it may be playing a more important role in the flooding. High water events and flood retention do not correlate well with precipitation for the region. It appears that releases at the dam, or periods of water retention, are driving the long flooding periods upstream. Negative impacts to the region from the flooding include property damage, loss of arable land, and environmental effects.

  20. Morphological impact of river below dam due to reservoir desiltation operation in Taiwan

    NASA Astrophysics Data System (ADS)

    Wang, H. W.; Lee, F. Z.; Lai, J. S.; Huang, C. C.; Kang, S. Y.

    2014-12-01

    The morphological impact of river below dams due to such reservoir desiltation operation was considered and Shihmen reservoir was adopted to discuss such issue due to the new sediment venting tunnel was implemented from 2013 in this study. The Shihmen reservoir had a natural drainage area of 762.4 km2 and located at the northern Taiwan. Due to serious sediment deposition problem from 2004 induced by Typhoon AERE, the stratified withdraw facility was built at dam site to avoid the lack of public water and the one of venting tunnel of power plant was designed to vent turbidity current (Fig. 1(a)). In 2013, the sediment venting tunnel was first operated during Typhoon Soulik and abundant sediment was released to the downstream river. The 2D numerical model with sediment transport consideration was adopted to investigate morphological impact of downstream river, especially at Jiangzicui area in Fig. 1(b). Due to ecological wet land, flood diversion work and ferry boat transportation were concentrated in this area, the sediment transportation and morphological impact is important to be realized. The Fig. 1(b) shows the original morphological bed form before sediment releasing from sediment venting tunnel and Fig. 1(c) shows the simulation results after sediment releasing from sediment venting. It seems 0.2 m morphological changing due to this operation. Fig. 1(d) is the field morphological survey after Typhoon Soulik and comparison to Fig. 1 (b), not significantly deposition or erosion is observed. According to the grain size of released sediment from Shihmen reservoir, d50 is approximately 10 μm and it is belonged to fine sediment. Therefore, the released sediment is classified clay and for the morphological impact is not significantly. So, morphological impact of downstream river below Shihmen dam due to reservoir desiltation operation is unapparent after Typhoon Soulik at Jiangzicui area. Keywords: venting tunnel, turbid current, morphological impact, 2D numerical

  1. Simulation and control of morphological changes due to dam removal in the Sandy River, Oregon, USA

    NASA Astrophysics Data System (ADS)

    Ding, Y.; Altinakar, M. S.

    2015-03-01

    A one-dimensional channel evolution simulation model (CCHE1D) is applied to assess morphological changes in a reach of the Sandy River, Oregon, USA, due to the Marmot Dam removal in 2007. Sediment transport model parameters (e.g. sediment transport capacity, bed roughness coefficient) were calibrated using observed bed changes after the dam removal. The validated model is then applied to assess long-term morphological changes in response to a 10-year hydrograph selected from historical storm water records. The long-term assessment of sedimentation gives a reasonable prediction of morphological changes, expanding erosion in reservoir and growing deposition immediately downstream of the dam site. This prediction result can be used for managing and planning river sedimentation after dam removal. A simulation-based optimization model is also applied to determine the optimal sediment release rates during dam-removal that will minimize the morphological changes in the downstream reaches.

  2. Factors affecting detectability of river otters during sign surveys

    USGS Publications Warehouse

    Jeffress, Mackenzie R.; Paukert, Craig P.; Sandercock, Brett K.; Gipson, Philip S.

    2011-01-01

    Sign surveys are commonly used to study and monitor wildlife species but may be flawed when surveys are conducted only once and cover short distances, which can lead to a lack of accountability for false absences. Multiple observers surveyed for river otter (Lontra canadensis) scat and tracks along stream and reservoir shorelines at 110 randomly selected sites in eastern Kansas from January to April 2008 and 2009 to determine if detection probability differed among substrates, sign types, observers, survey lengths, and near access points. We estimated detection probabilities (p) of river otters using occupancy models in Program PRESENCE. Mean detection probability for a 400-m survey was highest in mud substrates (p = 0.60) and lowest in snow (p = 0.18) and leaf litter substrates (p = 0.27). Scat had a higher detection probability (p = 0.53) than tracks (p = 0.18), and experienced observers had higher detection probabilities (p < 0.71) than novice observers (p < 0.55). Detection probabilities increased almost 3-fold as survey length increased from 200 m to 1,000 m, and otter sign was not concentrated near access points. After accounting for imperfect detection, our estimates of otter site occupancy based on a 400-m survey increased >3-fold, providing further evidence of the potential negative bias that can occur in estimates from sign surveys when imperfect detection is not addressed. Our study identifies areas for improvement in sign survey methodologies and results are applicable for sign surveys commonly used for many species across a range of habitats.

  3. Imbalance of Nature due to Contaminant Loads in the Culiacan River Watershed, Sinaloa, México

    NASA Astrophysics Data System (ADS)

    García Páez, F.; Ley-Aispuro, E.

    2013-05-01

    The Culiacan River discharges runoff from a large agricultural watershed into the wetlands at Ensenada de Pabellones ranked as a priority marine region of Mexico due to its high biodiversity and the economic importance of its fishing resources. This research estimated potential contaminant loads for BOD5, TSS, N and P from stormwater runoff and associated land use in the watershed. Previous studies had demonstrated the imbalance of nature due to land use change causing contamination by heavy metals, pesticides, sediment, phosphorus and eutrophication (Lopez and Osuna, 2002; Green and Paez, 2004, Gonzalez et al., 2006; Osuna et al., 2007). The methodology included: Characterizing the watershed according to land use, soil, vegetation, annual runoff and population density by sub-watershed; estimating the potential contaminant load and annual average concentrations of contaminants using the PLOAD program, comparing the result with monitored contaminant concentrations; and identifying the impact of pollutant loads in the watershed and coastal ecosystems and proposing management strategies to reduce or reverse the imbalance of nature caused by contamination in the Culiacan River watershed. Calculated contaminant loads in tonne/year were 13,682.4 of BOD5; 503,621.8 of TSS; 5,975.7 of N and 1,789.1 of P. The Tamazula and Humaya rivers watersheds provide 72% of the total load of BOD5, 68.5% of TSS, 77.6% of N and 62.7% of P discharged to the wetlands. Monitored results include: 89% of temperature observations were above 21°C, which is stressful to aquatic life due to a subsequent decrease in dissolved oxygen; 100% of the observations of P exceeded the ecological criteria for water quality; 71.5% of the observations for DO from 2001 to 2011, were above the ecological criteria for protection of aquatic life and 91.5% met the criteria for use in drinking water; 100% of the observations for BOD5 values remained in the range of Excellent to Good; 22% of the observations for the

  4. Landscape changes as a factor affecting the course and consequences of extreme floods in the Otava river basin, Czech Republic.

    PubMed

    Langhammer, Jakub; Vilímek, Vít

    2008-09-01

    The paper presents the analysis of anthropogenical modifications of the landscape in relation to the course and consequences of floods. The research was conducted in the Otava river basin which represents the core zone of the extreme flood in August 2002 in Central Europe. The analysis was focused on the key indicators of landscape modification potentially affecting the runoff process - the long-term changes of land-use, changes of land cover structure, land drainage, historical shortening of the river network and the modifications of streams and floodplains. The information on intensity and spatial distribution of modifications was derived from different data sources--historical maps, available GIS data, remote sensing and field mapping. The results revealed a high level of spatial diversity of anthropogenical modifications in different parts of the river basin. The intensive modifications in most of indicators were concentrated in the lowland region of the river basin due to its agricultural use; however important changes were also recorded in the headwater region of the basin. The high spatial diversity of the modifications may result in their varying effect on the course and consequences of floods in different parts of the river basin. This effect is demonstrated by the cluster analysis based on the matrix of indicators of stream and floodplain modification, physiogeographical characteristics and geomorphological evidences of the flood in August 2002, derived from the individual thematic layers using GIS.

  5. The grain size gap and abrupt gravel-sand transitions in rivers due to suspension fallout

    NASA Astrophysics Data System (ADS)

    Lamb, Michael P.; Venditti, Jeremy G.

    2016-04-01

    Median grain sizes on riverbeds range from boulders in uplands to silt in lowlands; however, rivers with ~1-5 mm diameter bed sediment are rare. This grain size gap also marks an abrupt transition between gravel- and sand-bedded reaches that is unlike any other part of the fluvial network. Abrupt gravel-sand transitions have been attributed to rapid breakdown or rapid transport of fine gravel, or a bimodal sediment supply, but supporting evidence is lacking. Here we demonstrate that rivers dramatically lose the ability to transport sand as wash load where bed shear velocity drops below ~0.1 m/s, forcing an abrupt transition in bed-material grain size. Using thresholds for wash load and initial motion, we show that the gap emerges only for median bed-material grain sizes of ~1-5 mm due to Reynolds number dependencies in suspension transport. The grain size gap, therefore, is sensitive to material properties and gravity, with coarser gaps predicted on Mars and Titan.

  6. Factors affecting overall satisfaction with a river recreation experience

    NASA Astrophysics Data System (ADS)

    Herrick, Theresa A.; McDonald, Cary D.

    1992-03-01

    Visitor satisfaction has been a consistently stated goal of outdoor recreation management. Recreation resource managers provide opportunities for the visiting public with the anticipation of satisfying the needs of the visitors. Management efforts are often evaluated in terms of visitor satisfaction. In the recent decade, a multiple satisfactions approach has been the primary research paradigm guiding visitor satisfaction research. This paradigm has focused primarily upon behavioral-type dimensions such as crowding, goal attainment, and resource impacts resulting from behavior. The purpose of this study was to examine the importance of a setting dimension relative to behavioral-type dimensions for explaining differences in visitor satisfaction. A sample of 895 river visitors were sent a questionnaire in the mail; 682 were returned for a 76.2% response rate. Regression analysis indicated the setting dimension was ranked as one of the most important dimensions for explaining differences in visitor satisfaction. Other dimensions considered included group behavior, perceived crowding, parking, past experience, encounters, use levels, and time waiting. Implications for management are discussed.

  7. Estimating salinity intrusion effects due to climate change on the Lower Savannah River Estuary

    USGS Publications Warehouse

    Conrads, Paul A.; Roehl, Edwin A.; Daamen, Ruby C.; Cook, John B.; Sexton, Charles T.; Tufford, Daniel L.; Carbone, Gregory J.; Dow, Kristin

    2010-01-01

    The ability of water-resource managers to adapt to future climatic change is especially challenging in coastal regions of the world. The East Coast of the United States falls into this category given the high number of people living along the Atlantic seaboard and the added strain on resources as populations continue to increase, particularly in the Southeast. Increased temperatures, changes in regional precipitation regimes, and potential increased sea level may have a great impact on existing hydrological systems in the region. The Savannah River originates at the confluence of the Seneca and Tugaloo Rivers, near Hartwell, Ga., and forms the state boundary between South Carolina and Georgia. The J. Strom Thurmond Dam and Lake, located 238 miles upstream from the Atlantic Ocean, is responsible for most of the flow regulation that affects the Savannah River from Augusta, Ga., to the coast. The Savannah Harbor experiences semi-diurnal tides of two low and two high tides in a 24.8-hour period with pronounced differences in tidal range between neap and spring tides occurring on a 14-day and 28-day lunar cycle. Salinity intrusion results from the interaction of three principal forces - streamflow, mean tidal water levels, and tidal range. To analyze, model, and simulate hydrodynamic behaviors at critical coastal streamgages in the Lower Savannah River Estuary, data-mining techniques were applied to over 15 years of hourly streamflow, coastal water-quality, and water-level data. Artificial neural network (ANN) models were trained to learn the variable interactions that cause salinity intrusions. Streamflow data from the 9,850 square-mile Savannah River Basin were input into the model as time-delayed variables. Tidal inputs to the models were obtained by decomposing tidal water-level data into a “periodic” signal of tidal range and a “chaotic” signal of mean water levels. The ANN models were able to convincingly reproduce historical behaviors and generate

  8. Climatic and anthropogenic factors affecting river discharge to the global ocean, 1951-2000

    USGS Publications Warehouse

    Milliman, John D.; Farnsworth, K.L.; Jones, P.D.; Xu, K.H.; Smith, L.C.

    2008-01-01

    During the last half of the 20th century, cumulative annual discharge from 137 representative rivers (watershed areas ranging from 0.3 to 6300 ?? 103??km2) to the global ocean remained constant, although annual discharge from about one-third of these rivers changed by more than 30%. Discharge trends for many rivers reflected mostly changes in precipitation, primarily in response to short- and longer-term atmospheric-oceanic signals; with the notable exception of the Parana, Mississippi, Niger and Cunene rivers, few of these "normal" rivers experienced significant changes in either discharge or precipitation. Cumulative discharge from many mid-latitude rivers, in contrast, decreased by 60%, reflecting in large part impacts due to damming, irrigation and interbasin water transfers. A number of high-latitude and high-altitude rivers experienced increased discharge despite generally declining precipitation. Poorly constrained meteorological and hydrological data do not seem to explain fully these "excess" rivers; changed seasonality in discharge, decreased storage and/or decreased evapotranspiration also may play important roles. ?? 2008 Elsevier B.V. All rights reserved.

  9. Sediment Metal Concentration Survey Along the Mine-Affected Molonglo River, NSW, Australia.

    PubMed

    Wadige, Chamani P M Marasinghe; Taylor, Anne M; Krikowa, Frank; Maher, William A

    2016-04-01

    Metal concentrations were measured in sediments of the mine-affected Molonglo River to determine current metal concentrations and distribution along the river. Compared with an uncontaminated site at 6.5 km upstream of the Captains Flat mine, sediments collected from the river at ≤12.5 km distance below the mine had a significantly higher percentage of finely divided silt and clay with higher concentrations of cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn). The measured metal concentrations in the mine affected sites of the river were in the following order: Zn = 697-6818 > Pb = 23-1796 > Cu = 10-628 > Cd = 0.13-8.7 µg/g dry mass. The highest recorded metal concentrations were Cd at 48, Cu at 45, Pb at 240, and Zn at 81 times higher than the background concentrations of these metals in the river sediments. A clear sediment metal-contamination gradient from the mine site to 63 km downstream was established for Cd, Cu, Pb, and Zn in the river sediments. Compared with sediment metal concentrations before a major flood in 2010, only Zn concentrations increased. For all of the mine-affected sites studied, Cd and Zn concentrations exceeded the (ANZECC/ARMCANZ, Australian and New Zealand guidelines for fresh and marine water quality. Australian and New Zealand Environment and Conservation Council/Agriculture and Resource Management Council of Australia and New Zealand, 2000) interim sediment-quality guidelines low values for Cd (1.5 µg/g dry mass) and the high value for Zn (410 µg/g dry mass). Existing metal loads in the riverbed sediments may still be adversely affecting the river infauna. PMID:26795293

  10. Scale-dependent factors affecting North American river otter distribution in the midwest

    USGS Publications Warehouse

    Jeffress, Mackenzie R.; Paukert, C.P.; Whittier, Joanna B.; Sandercock, B.K.; Gipson, P.S.

    2011-01-01

    The North American river otter (Lontra canadensis) is recovering from near extirpation throughout much of its range. Although reintroductions, trapping regulations and habitat improvements have led to the reestablishment of river otters in the Midwest, little is known about how their distribution is influenced by local- and landscape-scale habitat. We conducted river otter sign surveys from Jan. to Apr. in 2008 and 2009 in eastern Kansas to assess how local- and landscape-scale habitat factors affect river otter occupancy. We surveyed three to nine 400-m stretches of stream and reservoir shorelines for 110 sites and measured local-scale variables (e.g., stream order, land cover types) within a 100 m buffer of the survey site and landscape-scale variables (e.g., road density, land cover types) for Hydrological Unit Code 14 watersheds. We then used occupancy models that account for the probability of detection to estimate occupancy as a function of these covariates using Program PRESENCE. The best-fitting model indicated river otter occupancy increased with the proportion of woodland cover and decreased with the proportion of cropland and grassland cover at the local scale. Occupancy also increased with decreased shoreline diversity, waterbody density and stream density at the landscape scale. Occupancy was not affected by land cover or human disturbance at the landscape scale. Understanding the factors and scale important to river otter occurrence will be useful in identifying areas for management and continued restoration. ?? 2011, American Midland Naturalist.

  11. Factors affecting nutrient trends in major rivers of the Chesapeake Bay Watershed

    USGS Publications Warehouse

    Sprague, Lori A.; Langland, M.J.; Yochum, S.E.; Edwards, R.E.; Blomquist, J.D.; Phillips, S.W.; Shenk, G.W.; Preston, S.D.

    2000-01-01

    Trends in nutrient loads and flow-adjusted concentrations in the major rivers entering Chesapeake Bay were computed on the basis of water-quality data collected between 1985 and 1998 at 29 monitoring stations in the Susquehanna, Potomac, James, Rappahannock, York, Patuxent, and Choptank River Basins. Two computer models?the Chesapeake Bay Watershed Model (WSM) and the U.S. Geological Survey?s 'Spatially Referenced Regressions on Watershed attributes' (SPARROW) Model?were used to help explain the major factors affecting the trends. Results from WSM simulations provided information on temporal changes in contributions from major nutrient sources, and results from SPARROW model simulations provided spatial detail on the distribution of nutrient yields in these basins. Additional data on nutrient sources, basin characteristics, implementation of management practices, and ground-water inputs to surface water were analyzed to help explain the trends. The major factors affecting the trends were changes in nutrient sources and natural variations in streamflow. The dominant source of nitrogen and phosphorus from 1985 to 1998 in six of the seven tributary basins to Chesapeake Bay was determined to be agriculture. Because of the predominance of agricultural inputs, changes in agricultural nutrient sources such as manure and fertilizer, combined with decreases in agricultural acreage and implementation of best management practices (BMPs), had the greatest impact on the trends in flow-adjusted nutrient concentrations. Urban acreage and population, however, were noted to be increasing throughout the Chesapeake Bay Watershed, and as a result, delivered loads of nutrients from urban areas increased during the study period. Overall, agricultural nutrient management, in combination with load decreases from point sources due to facility upgrades and the phosphate detergent ban, led to downward trends in flow-adjusted nutrient concentrations atmany of the monitoring stations in the

  12. The risk of river pollution due to washout from contaminated floodplain water bodies during high floods

    NASA Astrophysics Data System (ADS)

    Lyubimova, Tatyana; Lepikhin, Anatoly; Parshakova, Yanina; Tiunov, Alexey

    2016-04-01

    Today, the potential impact of extremely high floods, which in the last years have become a rather frequent weather-related disaster, is the problem of primary concern. In studies of the potential impact of floods the emphasis is placed first of all on the estimation of possible flood zones and the analysis of the flow regimes in these zones. However, in some cases the hydrochemical parameters related to changes in the chemical composition of water are more important than the hydraulic parameters. It is generally believed that the higher is the flow rate, the more intensive is the process of dissolution, i.e. the lower is the concentration of limiting contaminants in water. However, this statement is valid provided that flooding does not activate new sources of water pollution such as contaminated floodplain water bodies located in the vicinity of water supply systems. Being quite reliable and safe at small and moderate discharges, in the case of extremely high level of river waters they become intensive sources of water pollution, essentially limiting the water consumption schedule for downstream water consumers. It should be noted that compared to the well-studied mechanisms of waste discharge due to failure of hydraulic engineering structures by flood waves, the mechanisms of pollutant washout from the contaminated floodplain water bodies by the flood waves is still poorly understood. We analyze the impacts of such weather-related events on the quality of water in the water intake system, taking as an example, the section of the Vyatka River located in the Prikamskaya lowland of the Russian Federation. The risk of river pollution due to washout from the contaminated floodplain water bodies during high floods is studied by hydrodynamical modeling in the framework of combined approach using one-, two- and three-dimensional hydrodynamic models are implemented and by in situ measurements. It is shown that during high floods the removal of pollutants from the

  13. Integrated Hatchery Operations : Existing Policy Affecting Hatcheries in the Columbia River Basin, 1992 Annual Report.

    SciTech Connect

    Shelldrake, Tom

    1993-05-01

    Collected together in this document is relevant laws and policy of the US Fish and Wildlife Service, Washington State Department of Wildlife, Oregon State, Washington Department of Fisheries, and Idaho Department of Fish and Game as they affect hatcheries in the Columbia River Basin.

  14. RECONSTRUCTION OF INDIVIDUAL DOSES DUE TO MEDICAL EXPOSURES FOR MEMBERS OF THE TECHA RIVER COHORT

    SciTech Connect

    Shagina, N. B.; Golikov, V.; Degteva, M. O.; Vorobiova, M. I.; Anspaugh, L. R.; Napier, Bruce A.

    2012-11-01

    Purpose: To describe a methodology for reconstruction of doses due to medical exposures for members of the Techa River Cohort (TRC) who received diagnostic radiation at the clinic of the Urals Research Center for Radiation Medicine (URCRM) in 1952–2005. To calculate doses of medical exposure for the TRC members and compare with the doses that resulted from radioactive contamination of the Techa River. Material and Methods: Reconstruction of individual medical doses is based on data on x-ray diagnostic procedures available for each person examined at the URCRM clinics and values of absorbed dose in 12 organs per typical x-ray procedure calculated with the use of a mathematical phantom. Personal data on x-ray diagnostic examinations have been complied in the computerized “Registry of x-ray diagnostic procedures.” Sources of information are archival registry books from the URCRM x-ray room (available since 1956) and records on x-ray diagnostic procedures in patient-case histories (since 1952). The absorbed doses for 12 organs of interest have been evaluated per unit typical x-ray procedure with account taken of the x-ray examination parameters characteristic for the diagnostic machines used at the URCRM clinics. These parameters have been evaluated from published data on technical characteristics of the x-ray diagnostic machines used at the URCRM clinics in 1952–1988 and taken from the x-ray room for machines used at the URCRM in 1989–2005. Absorbed doses in the 12 organs per unit typical x-ray procedure have been calculated with use of a special computer code, EDEREX, developed at the Saint-Petersburg Research Institute of Radiation Hygiene after Professor P.V. Ramzaev. Individual accumulated doses of medical exposure have been calculated with a computer code, MEDS (Medical Exposure Dosimetry System), specifically developed at the URCRM. Results: At present, the “Registry of x-ray diagnostic procedures” contains information on individual x

  15. Factors affecting pesticide occurrence and transport in a large Midwestern river basin

    USGS Publications Warehouse

    Crawford, Charles G.

    2001-01-01

    Several factors affect the occurrence and transport of pesticides in surface waters of the 29,400 km2 White River Basin in Indiana. A relationship was found between pesticide use and the average annual concentration of that pesticide in the White River, although this relationship varies for different classes of pesticides. About one percent of the mass applied of each of the commonly used agricultural herbicides was transported from the basin via the White River. Peak pesticide concentrations were typically highest in late spring or early summer and were associated with periods of runoff following application. Concentrations of diazinon were higher in an urban basin than in two agricultural basins, corresponding to the common use of this insecticide on lawns and gardens in urban areas. Concentrations of atrazine, a corn herbicide widely used in the White River Basin, were higher in an agricultural basin with permeable, well-drained soils, than in an agricultural basin with less permeable, more poorly drained soils. Although use of butylate and cyanazine was comparable in the White River Basin between 1992 and 1994, concentrations in the White River of butylate, which is incorporated into soil, were substantially less than for cyanazine, which is typically applied to the soil surface.

  16. Deforestation offsets water balance changes due to climate variability in the Xingu River in eastern Amazonia

    NASA Astrophysics Data System (ADS)

    Panday, Prajjwal K.; Coe, Michael T.; Macedo, Marcia N.; Lefebvre, Paul; Castanho, Andrea D. de Almeida

    2015-04-01

    Deforestation reduced forest cover in Brazil's Xingu River Basin (XB; area: 510,000 km2) from 90% of the basin in the 1970s to 75% in the 2000s. Such large-scale land cover changes can substantially alter regional water budgets, but their influence can be difficult to isolate from that of natural climate variability. In this study, we estimate changes to the XB water balance from the 1970s to the 2000s due to climate variations and deforestation, using a combination of long-term observations of rainfall and discharge; satellite-based estimates of evapotranspiration (MODIS) and surface water storage (GRACE); and numerical modeling estimates (IBIS) of water budget components (evapotranspiration, soil moisture, and discharge). Model simulations over this period suggest that climate variations alone accounted for a -82 mm decrease (mean per unit area) in annual discharge (-14%, from 8190 m3 s-1 to 7806 m3 s-1), due to a -2% decrease in precipitation and +3% increase in evapotranspiration. Deforestation alone caused a +34 mm increase in annual discharge (+6%), as a result of a -3% decrease in evapotranspiration and +1% increase in soil moisture across the XB. Climate variability and land cover change thus had opposite effects on the XB water balance, with climate effects masking deforestation-induced changes to the water budget. Protected areas, which cover 55% of the basin, have helped to mitigate the effects of past deforestation on water recycling in the Xingu. However, our results suggest that continued deforestation outside protected areas could trigger changes of sufficient magnitude to offset climate variability.

  17. The nucleoporin Nup153 affects spindle checkpoint activity due to an association with Mad1

    PubMed Central

    Shimi, Takeshi

    2010-01-01

    The nucleoporin Nup153 is known to play pivotal roles in nuclear import and export in interphase cells and as the cell transitions into mitosis, Nup153 is involved in nuclear envelope breakdown. In this study, we demonstrate that the interaction of Nup153 with the spindle assembly checkpoint protein Mad1 is important in the regulation of the spindle checkpoint. Overexpression of human Nup153 in HeLa cells leads to the appearance of multinucleated cells and induces the formation of multipolar spindles. Importantly, it causes inactivation of the spindle checkpoint due to hypophosphorylation of Mad1. Depletion of Nup153 using RNA interference results in the decline of Mad1 at nuclear pores during interphase and more significantly causes a delayed dissociation of Mad1 from kinetochores in metaphase and an increase in the number of unresolved midbodies. In the absence of Nup153 the spindle checkpoint remains active. In vitro studies indicate direct binding of Mad1 to the N-terminal domain of Nup153. Importantly, Nup153 binding to Mad1 affects Mad1's phosphorylation status, but not its ability to interact with Mad2. Our data suggest that Nup153 levels regulate the localization of Mad1 during the metaphase/anaphase transition thereby affecting its phoshorylation status and in turn spindle checkpoint activity and mitotic exit. PMID:21327106

  18. Potential water quality changes due to corn expansion in the Upper Mississippi River Basin.

    PubMed

    Secchi, Silvia; Gassman, Philip W; Jha, Manoj; Kurkalova, Lyubov; Kling, Catherine L

    2011-06-01

    While biofuels may yield renewable fuel benefits, there could be downsides in terms of water quality and other environmental stressors, particularly if corn is relied upon exclusively as the feedstock. The consequences of increased corn production will depend importantly on where (and how) the additional corn is grown, which, in turn, depends on the characteristics of land and its associated profitability. Previous work has relied on rules of thumb for allocating land to increased acreage based on historical land use or other heuristics. Here, we advance our understanding of these phenomena by describing a modeling system that links an economics-driven land use model with a watershed-based water quality model for the Upper Mississippi River Basin (UMRB). This modeling system is used to assess the water quality changes due to increased corn acreage, which is associated with higher relative corn prices. We focus on six scenarios based on six realistic pairs of corn and soybean prices which correspond to a scale of decreasing soybean to corn price ratio. These price-driven land use changes provide estimates of the water quality effects that current biofuel policies may have in the UMRB. Our analysis can help evaluate the costs and environmental consequences associated with implementation strategies for the biofuel mandates of the new energy bill. The amounts of total N and P delivered to the outlet of the UMRB (located at Grafton, Illinois, USA) rise as corn production becomes more intensive in the region. Our results indicate that a 14.4% in corn acreage in the watershed due to corn intensification in the most economically profitable locations would result in a 5.4% increase in total nitrogen loads and in a 4.1% increase in total phosphorus loads at Grafton. Our most aggressive scenario, driven by high but not out of reach crop prices, results in about a 57% increase in corn acreage with a corresponding 18.5% increase in N and 12% increase in P. These are somewhat

  19. Channel morphodynamics and habitat recovery in a river reach affected by gravel-mining (River Ésera, Ebro basin)

    NASA Astrophysics Data System (ADS)

    Lopez-Tarazon, J. A.; Lobera, G.; Andrés-Doménech, I.; Martínez-Capel, F.; Muñoz-Mas, R.; Vallés, F.; Tena, A.; Vericat, D.; Batalla, R. J.

    2012-04-01

    Physical processes in rivers are the result of the interaction between flow regime and hydraulics, morphology, sedimentology and sediment transport. The frequency and magnitude of physical disturbance (i.e. bed stability) control habitat integrity and, consequently, ecological diversity of a particular fluvial system. Most rivers experience human-induced perturbations that alter such hydrosedimentary equilibrium, thus affecting the habitat of aquatic species. A dynamic balance may take long time to be newly attained. Within this context, gravel mining is well known to affect channel characteristics mostly at the local scale, but its effect may also propagate downstream and upstream. Sedimentary forms are modified during extraction and habitat features are reduced or even eliminated. Effects tend to be most acute in contrasted climatic environments, such as the Mediterranean areas, in which climatic and hydrological variability maximises effects of impacts and precludes short regeneration periods. Present research focuses on the evolution of a river reach, which has experienced an intense gravel extraction. The selected area is located in the River Ésera (Ebro basin), where interactions between morphodynamics and habitat recovery are examined. Emphasis is put on monitoring sedimentary, morphological and hydraulic variables to later compare pre (t0) and post (t1, t2... tn) extraction situations. Methodology for all time monitoring steps (i.e. ti) includes: i) characterization of grain size distribution at all of the different hydromorphological units within the reach; ii) description of channel morphology (together with changes before and after floods) by means of close-range aerial photographs, which are taken with a digital camera attached to a 1m3 helium balloon (i.e. BLIMP); and iii) determination of flow parameters from 2D hydraulic modelling that is based on detailed topographical data obtained from Leica® GNSS/GPS and robotic total station, and River

  20. How does floodplain width affect floodplain river ecology? A preliminary exploration using simulations

    NASA Astrophysics Data System (ADS)

    Power, Mary E.; Parker, Gary; Dietrich, William E.; Sun, Adrian

    1995-09-01

    Hydraulic food chain models allow us to explore the linkages of river discharge regimes and river-floodplain morphology to the structure and dynamics of modeled food webs. Physical conditions (e.g. depth, width, velocity) that vary with river discharge affect the performance (birth, growth, feeding, movement, or death rates) of organisms or trophic groups. Their performances in turn affect their impacts on food webs and ecosystems in channel and floodplain habitats. Here we explore the impact of floodplain width (modeled as 1 ×, 10× and 40× the channel width) on a food web with two energy sources (detritus and vegetation), invertebrates that consume these, a size structured fish population which consumes invertebrates and in which larger fish cannibalize small fish, and birds which feed on large fish. Hydraulic linkages to trophic dynamics are assumed to be mediated in three ways: birds feed efficiently only in shallow water; plant carrying capacity varies non-linearly with water velocity, and mobile and drifting organisms are diluted and concentrated with spillover of river discharge to the floodplain, and its reconfinement to the channel. Aspects of this model are based on field observations of Junk and Bailey from the Amazon, of Sparks from the Mississippi, and on our observations of the Fly River in Papua New Guinea. The model produced several counter-intuitive results. Biomass of invertebrates and fish increased with floodplain width, but much more rapidly from 1 × to 10 × floodplains than from 10 × to 40 × floodplains. For birds, maximum biomass occurred on the 10× floodplain. Initially high bird biomass on the 40 × floodplain declined to extinction over time, because although favorable fishing conditions (shallow water) were most prolonged on the widest floodplain, this advantage was more than offset by the greater dilution of prey after spillover. Bird predation on large fish sometimes increased their biomass, by reducing cannibalism and thereby

  1. Flood Deposition Patterns and Channel Migration due to a 10-year flood event: the case of the Indus River flood 2010

    NASA Astrophysics Data System (ADS)

    Kettner, A. J.; Syvitski, J. P.; Overeem, I.; Brakenridge, G. R.

    2013-12-01

    Fluvial geomorphological processes evolve the landscape and are often referred to as processes that act for hundred to thousands of years before making a noticeable change in landforms. For the Indus River, landscape evolution has been intensified due to human interference. Failure in repairing its levees from previous floods led in July 2010 during a not exceptional discharge event (~10 year recurrence interval) to a large avulsion and flooding disaster that caused ~2,000 fatalities. Examining pre- and post flood maps by analyzing MODIS and ASTER-A1 data allowed us to determine the extent of sandy flood deposits and to quantify channel migration patterns. The typical pattern of inner bend deposition (due to helical flow) and outer bend erosion were less pronounced. We hypothesize that when flow exceeds bankfull conditions, deposition is more uniform and no longer constrained by the streambed geometry. We observe that the inner and the outer river bend receive similar amounts of sandy deposits (43% versus 57% respectively). Crevasse splaying was widespread and appeared to occur as a flow stripping process again both upon the point bars as well as in river outer bends. Channel activity (defined as the areal shift of the pre- and post river centerline), sinuosity, slope and lateral sediment deposition were determined for 50km river stretches. Analyzes reveal that flood deposits extend generally less than 2 km from the main channel axis. Furthermore, channel activity correlates negatively with channel sinuosity and lateral distance of sediment deposition and positively with slope. The river channel migrated over 100's of meters during the July 2010 flood event. Lateral migration averaged ~340m along a 1000km stretch of the Indus River over a period of just 52 days. Although this discharge event was not exceptional, lateral migration was significant and deposition impacts the active river floodplain. Remarkably, most sediments are deposited downstream the large

  2. Benzene dynamics and biodegradation in alluvial aquifers affected by river fluctuations.

    PubMed

    Batlle-Aguilar, J; Morasch, B; Hunkeler, D; Brouyère, S

    2014-01-01

    The spatial distribution and temporal dynamics of a benzene plume in an alluvial aquifer strongly affected by river fluctuations was studied. Benzene concentrations, aquifer geochemistry datasets, past river morphology, and benzene degradation rates estimated in situ using stable carbon isotope enrichment were analyzed in concert with aquifer heterogeneity and river fluctuations. Geochemistry data demonstrated that benzene biodegradation was on-going under sulfate reducing conditions. Long-term monitoring of hydraulic heads and characterization of the alluvial aquifer formed the basis of a detailed modeled image of aquifer heterogeneity. Hydraulic conductivity was found to strongly correlate with benzene degradation, indicating that low hydraulic conductivity areas are capable of sustaining benzene anaerobic biodegradation provided the electron acceptor (SO4 (2-) ) does not become rate limiting. Modeling results demonstrated that the groundwater flux direction is reversed on annual basis when the river level rises up to 2 m, thereby forcing the infiltration of oxygenated surface water into the aquifer. The mobilization state of metal trace elements such as Zn, Cd, and As present in the aquifer predominantly depended on the strong potential gradient within the plume. However, infiltration of oxygenated water was found to trigger a change from strongly reducing to oxic conditions near the river, causing mobilization of previously immobile metal species and vice versa. MNA appears to be an appropriate remediation strategy in this type of dynamic environment provided that aquifer characterization and targeted monitoring of redox conditions are adequate and electron acceptors remain available until concentrations of toxic compounds reduce to acceptable levels.

  3. Initial Sediment Transport Model of the Mining-Affected Aries River Basin, Romania

    USGS Publications Warehouse

    Friedel, Michael J.; Linard, Joshua I.

    2008-01-01

    The Romanian government is interested in understanding the effects of existing and future mining activities on long-term dispersal, storage, and remobilization of sediment-associated metals. An initial Soil and Water Assessment Tool (SWAT) model was prepared using available data to evaluate hypothetical failure of the Valea Sesei tailings dam at the Rosia Poieni mine in the Aries River basin. Using the available data, the initial Aries River Basin SWAT model could not be manually calibrated to accurately reproduce monthly streamflow values observed at the Turda gage station. The poor simulation of the monthly streamflow is attributed to spatially limited soil and precipitation data, limited constraint information due to spatially and temporally limited streamflow measurements, and in ability to obtain optimal parameter values when using a manual calibration process. Suggestions to improve the Aries River basin sediment transport model include accounting for heterogeneity in model input, a two-tier nonlinear calibration strategy, and analysis of uncertainty in predictions.

  4. Occurrence of perchloroethylene in surface water and fish in a river ecosystem affected by groundwater contamination.

    PubMed

    Wittlingerová, Zdena; Macháčková, Jiřina; Petruželková, Anna; Zimová, Magdalena

    2016-03-01

    Long-term monitoring of the content of perchloroethylene (PCE) in a river ecosystem affected by groundwater contamination was performed at a site in the Czech Republic. The quality of surface water was monitored quarterly between 1994 and 2013, and fish were collected from the affected ecosystem to analyse the content of PCE in their tissue in 1998, 2011 and 2012. Concentrations of PCE (9-140 μg/kg) in the tissue of fish collected from the contaminated part of the river were elevated compared to the part of the river unaffected by the contamination (ND to 5 μg/kg PCE). The quality of surface water has improved as a result of groundwater remediation during the evaluated period. Before the remedial action, PCE concentrations ranged from 30 to 95 μg/L (1994-1997). Following commencement of remedial activities in September 1997, a decrease in the content of PCE in the surface water to 7.3 μg/L (1998) and further to 1 μg/L (2011) and 1.1 μg/L (2012) led to a progressive decrease in the average concentration of PCE in the fish muscle tissue from 79 μg/kg (1998) to 24 (2011) and 30 μg/kg (2012), respectively. It was determined that the bioconcentration of PCE does not have a linear dependence because the decrease in contamination in the fish muscle tissue is not directly proportional to the decrease in contamination in the river water. The observed average bioconcentration factors were 24 and 28 for the lower concentrations of PCE and 11 for the higher concentrations of PCE in the river. In terms of age, length and weight of the collected fish, weight had the greatest significance for bioconcentration, followed by the length, with age being evaluated as a less significant factor.

  5. Linking river, floodplain, and vadose zone hydrology to improve restoration of a coastal river affected by saltwater intrusion.

    PubMed

    Kaplan, D; Muñoz-Carpena, R; Wan, Y; Hedgepeth, M; Zheng, F; Roberts, R; Rossmanith, R

    2010-01-01

    Floodplain forests provide unique ecological structure and function, which are often degraded or lost when watershed hydrology is modified. Restoration of damaged ecosystems requires an understanding of surface water, groundwater, and vadose (unsaturated) zone hydrology in the floodplain. Soil moisture and porewater salinity are of particular importance for seed germination and seedling survival in systems affected by saltwater intrusion but are difficult to monitor and often overlooked. This study contributes to the understanding of floodplain hydrology in one of the last bald cypress [Taxodium distichum (L.) Rich.] floodplain swamps in southeast Florida. We investigated soil moisture and porewater salinity dynamics in the floodplain of the Loxahatchee River, where reduced freshwater flow has led to saltwater intrusion and a transition to salt-tolerant, mangrove-dominated communities. Twenty-four dielectric probes measuring soil moisture and porewater salinity every 30 min were installed along two transects-one in an upstream, freshwater location and one in a downstream tidal area. Complemented by surface water, groundwater, and meteorological data, these unique 4-yr datasets quantified the spatial variability and temporal dynamics of vadose zone hydrology. Results showed that soil moisture can be closely predicted based on river stage and topographic elevation (overall Nash-Sutcliffe coefficient of efficiency = 0.83). Porewater salinity rarely exceeded tolerance thresholds (0.3125 S m(-1)) for bald cypress upstream but did so in some downstream areas. This provided an explanation for observed vegetation changes that both surface water and groundwater salinity failed to explain. The results offer a methodological and analytical framework for floodplain monitoring in locations where restoration success depends on vadose zone hydrology and provide relationships for evaluating proposed restoration and management scenarios for the Loxahatchee River.

  6. Downstream changes of water quality in a lowland river due to groundwater inflows.

    NASA Astrophysics Data System (ADS)

    Zieba, Damian; Bar-Michalczyk, Dominika; Kania, Jarosław; Malina, Grzegorz; Michalczyk, Tomasz; Rozanski, Kazimierz; Witczak, Stanislaw; Wachniew, Przemyslaw; Zurek, Anna J.

    2016-04-01

    The Kocinka catchment (ca. 250 km2) in southern Poland receives substantial inflows of groundwater from a major fissured-carbonate aquifer polluted with nitrates originating from agriculture and domestic sewage. The 40 km long Kocinka river reveals large spatial variations in physical and chemical water properties with large downstream changes of nitrate concentrations. Detailed longitudinal surveys of such water characteristics as nitrate concentration, water temperature, pH, electric conductivity, stable isotopic composition, tritium concentration were performed in order to identify and quantify groundwater inflows. The river gains groundwater down to the 25 km from the source and a looses water further downstream. The subsequent increase and decrease of nitrate concentration in the upper and middle reaches of the river are caused by inflows of the, respectively, polluted and non-polluted groundwaters. The range of such changes can be even five-fold while the drop of nitrate concentration along the semi natural, 18 km long, lower reach where the river is well connected to its riparian and hyporheic zones nitrate loss is of the order of 10%. More significant nitrate losses were observed in the dammed reaches and in a small reservoir in the upper part of the river. Results of the study have implications for identification of measures that can be undertaken to reduce nitrate export from the catchment. Because of the role of groundwater in river runoff reduction of nitrate loads to the aquifer should be primary objective. Acknowledgements. The work was carried out as part of the BONUS Soils2Sea project on groundwater system (http:/www.soils2sea.eu) financed by the European Commission 7 FP contract 226536 and the statutory funds of the AGH University of Science and Technology (project No.11.11.140.026 and 11.11.220.01).

  7. Regional processes affecting dissolved organic material in the Sacramento-San Joaquin River system

    NASA Astrophysics Data System (ADS)

    Bergamaschi, B. A.

    2005-05-01

    The Central Valley of California, USA, is drained primarily by the Sacramento and San Joaquin River System into a delta that interacts tidally with the San Francisco Bay estuary. We use historical data along with molecular and isotopic tracers to determine the impact of land use, water impoundments, and diversions on dissolved organic material (DOM) concentration and quality. River-borne DOM supports two thirds of the heterotrophic demand of the estuary, lowers the quality of drinking water diversions from the delta, and affects the transport and methylation of mercury. DOM concentration in the rivers and delta varies by over a factor of 6 throughout the year, with a peak in early spring. Our previous results indicated that the delta DOM contribution to the estuary varies seasonally, supplying from 10 percent to 50 percent of the DOM exported by the river system into the estuary, with the greatest contribution occurring during winter and spring. Recent results using molecular source indicators suggest the DOM is largely added by local aquatic production rather than by terrestrial inputs, and is substantially altered by the heterotrophic microbial community. The molecular and isotopic results suggest that water management and land use significantly impact the timing and composition of DOM.

  8. LAND USE CHANGE DUE TO URBANIZATION FOR THE NEUSE RIVER BASIN

    EPA Science Inventory

    The Urban Growth Model (UGM) was applied to analysis of land use change in the Neuse River Basin as part of a larger project for estimating the regional and broader impact of urbanization. UGM is based on cellular automation (CA) simulation techniques developed at the University...

  9. Detection of changes in design discharges due to river engineering works by multilinear flow routing

    NASA Astrophysics Data System (ADS)

    Szolgay, J.; Danáčová, M.; Šúrek, P.

    2009-04-01

    The attenuation of flood waves on alluvial reaches of rivers was often influenced by engineering works carried out mostly during the last century. This study presents a framework that can be used for estimation of changes in design floods in consequence of these works by detecting changes in the travel-time vs. peak discharge relationship and implementing them into a conceptual hydrologic flood routing model. The applicability of the methodology is demonstrated on two case studies on the Morava and Danube Rivers in Slovakia. First empirical data on the travel time of the flood peaks were collected from a set of flood waves from periods before and after the river engineering works had been completed. The patterns observed in the travel-time vs. peak-discharge relationships from both periods were analysed. Next, a multilinear conceptual flow routing model was fitted to larger floods from both periods. The discrete state space representation of the Kalinin-Miljukov model was used as the basis for a multilinear discrete cascade flood routing model of the river reaches studied. The time distribution scheme of the model inputs was employed in the setup of the model. The travel-time parameter of the multilinear model was allowed to vary with the input discharge into the river reach according to a piecewise linear relationship. The shape and parameters of that relationship were estimated by optimisation on the flood waves from the pre- and post-river training periods with the help of a genetic algorithm using the performance of the multilinear model as the optimization criterion. The resulting travel-time vs. discharge relationships were compared against those detected in the empirical data. It was shown that changes in the flood peak travel-times detected by the genetic optimisation of the performance of the multilinear model on a small number of floods exhibit the same tendencies as found in the empirical data. Since the changes detected in the attenuation of floods

  10. Geomorphic Framework to assess changes to aquatic habitat due to flow regulation and channel and floodplain alteration, Cedar River, Washington

    USGS Publications Warehouse

    Gendaszek, Andrew S.; Magirl, Christopher S.; Czuba, Christiana R.; Konrad, Christopher P.; Little, Rand

    2010-01-01

    Flow regulation, bank armoring, and floodplain alteration since the early 20th century have contributed to significant changes in the hydrologic regime and geomorphic processes of the Cedar River in Washington State. The Cedar River originates in the Cascade Range, provides drinking water to the Seattle metropolitan area, and supports several populations of anadromous salmonids. Flow regulation currently has limited influence on the magnitude, duration, and timing of high-flow events, which affect the incubation of salmonids as well as the production and maintenance of their habitat. Unlike structural changes to the channel and floodplain, flow regulation may be modified in the short-term to improve the viability of salmon populations. An understanding of the effects of flow regulation on those populations must be discerned over a range of scales from individual floods that affect the size of individual year classes to decadal high flow regime that influences the amount and quality of channel and off-channel habitat available for spawning and rearing. We present estimates of reach-scale sediment budgets and changes to channel morphology derived from historical orthoimagery, specific gage analyses at four long-term streamflow-gaging stations to quantify trends in aggradation, and hydrologic statistics of the magnitude and duration of peak streamflows. These data suggest a gradient of channel types from unconfined, sediment-rich segments to confined, sediment-poor segments that are likely to have distinct responses to high flows. Particle-size distribution data and longitudinal water surface and streambed profiles for the 56 km downstream of Chester Morse Lake measured in 2010 show the spatial extent of preferred salmonid habitat along the Cedar River. These historical and current data constitute a geomorphic framework to help assess different river management scenarios for salmonid habitat and population viability. PDF version of a presentation on changes to aquatic

  11. Bioaccumulation of mercury in benthic communities of a river ecosystem affected by mercury mining.

    PubMed

    Zizek, Suzana; Horvat, Milena; Gibicar, Darija; Fajon, Vesna; Toman, Mihael J

    2007-05-15

    The presence of mercury in the river Idrijca (Slovenia) is mainly due to 500 years of mercury mining in this region. In order to understand the cycling of mercury in the Idrijca ecosystem it is crucial to investigate the role of biota. This study is part of an ongoing investigation of mercury biogeochemistry in the river Idrijca, focusing on the accumulation and speciation of mercury in the lower levels of the food chain, namely filamentous algae, periphyton and macroinvertebrates. Mercury analysis and speciation in the biota and in water were performed during the spring, summer and autumn seasons at four locations on the river, representing different degrees of mercury contamination. Total (THg) and methyl mercury (MeHg) were measured. The results showed that the highest THg concentrations in biota correlate well with THg levels in sediments and water. The level of MeHg is spatially and seasonally variable, showing higher values at the most contaminated sites during the summer and autumn periods. The percentage of Hg as MeHg increases with the trophic level from water (0.1-0.8%), algae (0.5-1.3%), periphyton (1.6-8.8%) to macroinvertebrates (0.1-100%), which indicates active transformation, accumulation and magnification of mercury in the benthic organism of this heavily contaminated torrential river.

  12. [Spatial-temporal distributions of dissolved inorganic carbon and its affecting factors in the Yellow River estuary].

    PubMed

    Guo, Xing-Sen; Lü, Ying-Chun; Sun, Zhi-Gao; Wang, Chuan-Yuan; Zhao, Quan-Sheng

    2015-02-01

    Estuary is an important area contributing to the global carbon cycle. In order to analyze the spatial-temporal distribution characteristics of the dissolved inorganic carbon (DIC) in the surface water of Yellow River estuary. Samples were collected in spring, summer, fall, winter of 2013, and discussed the correlation between the content of DIC and environmental factors. The results show that, the DIC concentration of the surface water in Yellow River estuary is in a range of 26.34-39.43 mg x L(-1), and the DIC concentration in freshwater side is higher than that in the sea side. In some areas where the salinity is less than 15 per thousand, the DIC concentration appears significant losses-the maximum loss is 20.46%. Seasonal distribution of performance in descending order is spring, fall, winter, summer. Through principal component analysis, it shows that water temperature, suspended solids, salinity and chlorophyll a are the main factors affecting the variation of the DIC concentration in surface water, their contribution rate is as high as 83% , and alkalinity, pH, dissolved organic carbon, dissolved oxygen and other factors can not be ignored. The loss of DIC in the low area is due to the calcium carbonate sedimentation. DIC presents a gradually increasing trend, which is mainly due to the effects of water retention time, temperature, outside input and environmental conditions.

  13. Integrated uncertainty assessment of hydrological responses due to land cover change in a large river basin including feedback effects

    NASA Astrophysics Data System (ADS)

    Kumar, R.; Samaniego-Eguiguren, L. E.; Coskun, M.

    2010-12-01

    parameter sets'' which can represent the observed hydrologic behavior of a basin under an acceptable range. Using the ensemble of the integrated model runs generated by a sequential Monte Carlo simulation, the magnitude of the effects of the hydrological consequences of land cover change was assessed in a probabilistic way. The proposed approach was tested in a south German river basin of approximately 14~000 km2 which has endured a rapid land cover changes in the past four decades. Preliminary results of the study indicated that simple feedback rules for changes in transition probability of land cover status affect the local conditions of soil-water availability. However, marginal effects were noticed for the peak flow characteristics (e.g. frequency, magnitude and duration of high flows) which are mainly governed by the extreme meteorological conditions. Our current investigations also tries to account for climate change in the proposed approach, and we hope to report some results in due time.

  14. Response of the turbidity maximum zone in the Yangtze River Estuary due to human activities during the dry season.

    PubMed

    Chen, Xiaofeng; Shen, Zhenyao; Yang, Ye

    2016-09-01

    The interaction between a river and the sea results in a turbidity maximum zone (TMZ) within the estuary, which has a great impact on the local ecosystem. In the Yangtze River Estuary, the magnitude and extent of the TMZ vary with water discharge. In this study, the cumulative human activity altered the water discharge regime from the river to the estuary. In the post-Three Gorges Dam (TGD) period, water discharge increased by 35.10 % at Datong in February compared with that in the pre-TGD period. The effects of water discharge variation on the characteristics of the TMZ were analyzed during spring and neap tidal periods using the three-dimensional environmental fluid dynamic code (EFDC) model. The area of the TMZ decreased by 3.11 and 17.39 % during neap and spring tides, respectively. In addition, the upper limit of the TMZ moved 11.68 km seaward during neap tide, whereas the upper limit of the TMZ in the upstream and downstream areas moved seaward 9.65 and 2.34 km, respectively, during spring tide. These findings suggest that the area and location of the TMZ are more sensitive to upstream runoff during spring tide than during neap tide. These changes in the TMZ will impact the biochemical processes in the Yangtze River Estuary. In the foreseeable future, the distribution characteristic of TMZ will inevitably change due to variations in the Yangtze River discharge resulting from new human activities (i.e., new dams), which are being constructed upstream in the Yangtze River system.

  15. Response of the turbidity maximum zone in the Yangtze River Estuary due to human activities during the dry season.

    PubMed

    Chen, Xiaofeng; Shen, Zhenyao; Yang, Ye

    2016-09-01

    The interaction between a river and the sea results in a turbidity maximum zone (TMZ) within the estuary, which has a great impact on the local ecosystem. In the Yangtze River Estuary, the magnitude and extent of the TMZ vary with water discharge. In this study, the cumulative human activity altered the water discharge regime from the river to the estuary. In the post-Three Gorges Dam (TGD) period, water discharge increased by 35.10 % at Datong in February compared with that in the pre-TGD period. The effects of water discharge variation on the characteristics of the TMZ were analyzed during spring and neap tidal periods using the three-dimensional environmental fluid dynamic code (EFDC) model. The area of the TMZ decreased by 3.11 and 17.39 % during neap and spring tides, respectively. In addition, the upper limit of the TMZ moved 11.68 km seaward during neap tide, whereas the upper limit of the TMZ in the upstream and downstream areas moved seaward 9.65 and 2.34 km, respectively, during spring tide. These findings suggest that the area and location of the TMZ are more sensitive to upstream runoff during spring tide than during neap tide. These changes in the TMZ will impact the biochemical processes in the Yangtze River Estuary. In the foreseeable future, the distribution characteristic of TMZ will inevitably change due to variations in the Yangtze River discharge resulting from new human activities (i.e., new dams), which are being constructed upstream in the Yangtze River system. PMID:27287491

  16. Dissolved barium behavior in Louisiana Shelf waters affected by the Mississippi/Atchafalaya River mixing zone

    NASA Astrophysics Data System (ADS)

    Joung, DongJoo; Shiller, Alan M.

    2014-09-01

    In order to better understand the constraints on the use of barium as a coastal paleo-freshwater tracer, we surveyed the dissolved Ba distribution in Louisiana Shelf waters, including the Mississippi (MR) and Atchafalaya (AR) River plumes, during May and November 2008, and June/July 2009, which represent high, low and intermediate river discharges, respectively. Dissolved Ba was found dominantly in the <0.02 μm fraction, with no significant contribution from the 0.02-0.45 μm colloidal size fraction. Although apparent non-conservative surface water Ba behavior was observed during all three sampling periods, there were significant differences among the distribution patterns. River-seawater mixing experiments were supportive of substantial desorptive Ba addition only during the high discharge survey. At other times, input of Ba-enriched shelf bottom water as well as river endmember variability contributed to the apparent non-conservative behavior. During at least two of our surveys (high and intermediate river discharge), shelf bottom waters were significantly enriched in dissolved Ba relative to surface waters. While the cause of this enrichment (e.g., submarine groundwater discharge, dissolution/diffusion from the sediment, and/or an anthropogenic source such as drilling muds) could not be determined, we did observe that bottom Ba enrichment correlated with diminishing dissolved oxygen during summertime shelf bottom water hypoxia. Another interesting observation was Ba depletion in some high-salinity surface waters associated with a diatom bloom during June/July 2009. In addition, different Ba concentrations in the MR and AR appear related to inputs to the AR from the Red River as well as from the wetlands in the Atchafalaya River Basin. Overall, our study of the Ba distribution in Louisiana Shelf waters implies that the seasonal variation of the surface water Ba-salinity relationship could lead to a considerable uncertainty in salinity prediction when using Ba as

  17. Simulated long-term changes in river discharge and soil moisture due to global warming

    USGS Publications Warehouse

    Manabe, S.; Milly, P.C.D.; Wetherald, R.

    2004-01-01

    By use of a coupled ocean atmosphere-land model, this study explores the changes of water availability, as measured by river discharge and soil moisture, that could occur by the middle of the 21st century in response to combined increases of greenhouse gases and sulphate aerosols based upon the "IS92a" scenario. In addition, it presents the simulated change in water availability that might be realized in a few centuries in response to a quadrupling of CO2 concentration in the atmosphere. Averaging the results over extended periods, the radiatively forced changes, which are very similar between the two sets of experiments, were successfully extracted. The analysis indicates that the discharges from Arctic rivers such as the Mackenzie and Ob' increase by up to 20% (of the pre-Industrial Period level) by the middle of the 21st century and by up to 40% or more in a few centuries. In the tropics, the discharges from the Amazonas and Ganga-Brahmaputra rivers increase substantially. However, the percentage changes in runoff from other tropical and many mid-latitude rivers are smaller, with both positive and negative signs. For soil moisture, the results of this study indicate reductions during much of the year in many semiarid regions of the world, such as the southwestern region of North America, the northeastern region of China, the Mediterranean coast of Europe, and the grasslands of Australia and Africa. As a percentage, the reduction is particularly large during the dry season. From middle to high latitudes of the Northern Hemisphere, soil moisture decreases in summer but increases in winter.

  18. Factors affecting condition of flannelmouth suckers in the Colorado River, Grand Canyon, Arizona

    USGS Publications Warehouse

    Paukert, C.; Rogers, R.S.

    2004-01-01

    The impoundment of the Colorado River by Glen Canyon Dam, Arizona, in 1963 created a highly regulated environment in the Grand Canyon that altered the native fish populations, including the flannelmouth sucker Catostomus latipinnis. Flannelmouth suckers were sampled from 1991 to 2001 to determine seasonal, annual, and spatial trends in fish condition (i.e., relative weight [Wr]). Mean Wr peaked during the prespawn and spawning periods and was lowest in summer and fall, but it was never lower than 93. Condition was variable throughout the Grand Canyon but was typically greatest at intermediate distances from Glen Canyon Dam, possibly because of the increased number of warmwater tributaries in this reach. Flannelmouth sucker condition in September was positively correlated with Glen Canyon Dam discharge during summer (June-August); this result may be due to the larger euphotic zone and greater macroinvertebrate abundance observed during higher water flows. Increased dam discharge that stimulates river productivity may provide benefits for this native fish.

  19. Assessment of doses to the offspring of the Techa River cohort due to intakes of radionuclides by the mother.

    PubMed

    Degteva, M O; Tolstykh, E I; Vorobiova, M I

    2003-01-01

    The Techa River was contaminated as a result of radioactive releases by the Mayak plutonium production facility in 1949-1956. The residents of riverside communities were exposed to internal irradiation from radionuclides ingested mainly with river water, and also to external gamma irradiation resulting from shoreline and flood-plain contamination. The most important role in population exposure was played by (89,90)Sr and 137Cs. The persons born after the onset of the contamination have been identified as the 'Techa River Offspring Cohort' (TROC). The TROC has the potential to provide direct data on health effects in progeny that resulted from exposure of a general population to chronic radiation. This report describes the results of the calculation of fetal doses due to intakes of radionuclides by their mothers. Particular attention has been given to fetal dose from 90Sr because this nuclide is the most significant in terms of population dose for the Techa River. The comparison of the fetal bone marrow doses evaluated using different approaches proposed in the literature has shown a large dispersal in dose values. The main cause of this is the difference in model assumptions simplifying some developmental aspects of fetal haematopoiesis and bone formation. This paper presents an analysis of these basic assumptions that could be useful for further improvements in fetal dosimetry.

  20. Wetland loss due to land use change in the Lower Paraná River Delta, Argentina.

    PubMed

    Sica, Y V; Quintana, R D; Radeloff, V C; Gavier-Pizarro, G I

    2016-10-15

    Wetland loss is a global concern because wetlands are highly diverse ecosystems that provide important goods and services, thus threatening both biodiversity and human well-being. The Paraná River Delta is one of the largest and most important wetland ecosystems of South America, undergoing expanding cattle and forestry activities with widespread water control practices. To understand the patterns and drivers of land cover change in the Lower Paraná River Delta, we quantified land cover changes and modeled associated factors. We developed land cover maps using Landsat images from 1999 and 2013 and identified main land cover changes. We quantified the influence of different socioeconomic (distance to roads, population centers and human activity centers), land management (area within polders, cattle density and years since last fire), biophysical variables (landscape unit, elevation, soil productivity, distance to rivers) and variables related to extreme system dynamics (flooding and fires) on freshwater marsh conversion with Boosted Regression Trees. We found that one third of the freshwater marshes of the Lower Delta (163,000ha) were replaced by pastures (70%) and forestry (18%) in only 14years. Ranching practices (represented by cattle density, area within polders and distance to roads) were the most important factors responsible for freshwater marsh conversion to pasture. These rapid and widespread losses of freshwater marshes have potentially large negative consequences for biodiversity and ecosystem services. A strategy for sustainable wetland management will benefit from careful analysis of dominant land uses and related management practices, to develop an urgently needed land use policy for the Lower Delta. PMID:27369090

  1. Wetland loss due to land use change in the Lower Paraná River Delta, Argentina.

    PubMed

    Sica, Y V; Quintana, R D; Radeloff, V C; Gavier-Pizarro, G I

    2016-10-15

    Wetland loss is a global concern because wetlands are highly diverse ecosystems that provide important goods and services, thus threatening both biodiversity and human well-being. The Paraná River Delta is one of the largest and most important wetland ecosystems of South America, undergoing expanding cattle and forestry activities with widespread water control practices. To understand the patterns and drivers of land cover change in the Lower Paraná River Delta, we quantified land cover changes and modeled associated factors. We developed land cover maps using Landsat images from 1999 and 2013 and identified main land cover changes. We quantified the influence of different socioeconomic (distance to roads, population centers and human activity centers), land management (area within polders, cattle density and years since last fire), biophysical variables (landscape unit, elevation, soil productivity, distance to rivers) and variables related to extreme system dynamics (flooding and fires) on freshwater marsh conversion with Boosted Regression Trees. We found that one third of the freshwater marshes of the Lower Delta (163,000ha) were replaced by pastures (70%) and forestry (18%) in only 14years. Ranching practices (represented by cattle density, area within polders and distance to roads) were the most important factors responsible for freshwater marsh conversion to pasture. These rapid and widespread losses of freshwater marshes have potentially large negative consequences for biodiversity and ecosystem services. A strategy for sustainable wetland management will benefit from careful analysis of dominant land uses and related management practices, to develop an urgently needed land use policy for the Lower Delta.

  2. Non-Native Student's Communication Is Affected Due to the Lack of Pragmatic Competence

    ERIC Educational Resources Information Center

    Latha, V. G.; Rajan, Premalatha

    2012-01-01

    This paper aims at focusing how the lack of pragmatic competence affects student's communication in L2 (Second language) at tertiary level. The city based Indian students learn English which is their second language from 3 years onwards whereas the rural based students learn English only from 6 years onwards. This exposure of the L2 shows the…

  3. Factors affecting chick provisioning by Caspian Terns nesting in the Columbia River estuary

    USGS Publications Warehouse

    Anderson, S.K.; Roby, D.D.; Lyons, Donald E.; Collis, K.

    2005-01-01

    We investigated factors affecting chick provisioning by radio-tagged Caspian Terns (Sterna caspia) nesting in a large colony on East Sand Island in the Columbia River estuary during 2001. Caspian Tern predation on juvenile salmonids (Oncorhynchus spp.) in the estuary prompted resource managers to relocate ca. 9,000 pairs of terns nesting on Rice Island (river km 34) to East Sand Island (river km 8), where terns were expected to consume fewer salmonids in favor of marine forage fishes. This study investigated factors influencing foraging success, diet composition, and overall reproductive success at the managed Caspian Tern colony. Our results indicated that daytime colony attendance by nesting terns averaged 64% and decreased throughout the chick-rearing period, while duration of foraging trips averaged 47 min and increased during the same period; these seasonal changes were more strongly related to date than chick age. Average meal delivery rates to 2-chick broods (0.88 meals h-1) were 2.6 times greater than to 1-chick broods (0.33 meals h-1). Parents delivered more juvenile salmonids to chicks during ebb tides than flood tides, but meal delivery rates to the nest remained constant, suggesting diet composition tracks relative availability of prey species. Foraging trips resulting in delivery of juvenile salmonids averaged 68% longer than foraging trips for schooling marine forage fishes, indicating higher availability of marine prey near the colony. High availability of marine forage fish in the Columbia River estuary during 2001 was apparently responsible for high colony attendance, short foraging trips, high chick meal delivery rates, and high nesting success of Caspian Terns on East Sand Island.

  4. Form drag in rivers due to small-scale natural topographic features: 2. Irregular sequences

    USGS Publications Warehouse

    Kean, J.W.; Smith, J.D.

    2006-01-01

    The size, shape, and spacing of small-scale topographic features found on the boundaries of natural streams, rivers, and floodplains can be quite variable. Consequently, a procedure for determining the form drag on irregular sequences of different-sized topographic features is essential for calculating near-boundary flows and sediment transport. A method for carrying out such calculations is developed in this paper. This method builds on the work of Kean and Smith (2006), which describes the flow field for the simpler case of a regular sequence of identical topographic features. Both approaches model topographic features as two-dimensional elements with Gaussian-shaped cross sections defined in terms of three parameters. Field measurements of bank topography are used to show that (1) the magnitude of these shape parameters can vary greatly between adjacent topographic features and (2) the variability of these shape parameters follows a lognormal distribution. Simulations using an irregular set of topographic roughness elements show that the drag on an individual element is primarily controlled by the size and shape of the feature immediately upstream and that the spatial average of the boundary shear stress over a large set of randomly ordered elements is relatively insensitive to the sequence of the elements. In addition, a method to transform the topography of irregular surfaces into an equivalently rough surface of regularly spaced, identical topographic elements also is given. The methods described in this paper can be used to improve predictions of flow resistance in rivers as well as quantify bank roughness.

  5. Form drag in rivers due to small-scale natural topographic features: 1. Regular sequences

    USGS Publications Warehouse

    Kean, J.W.; Smith, J.D.

    2006-01-01

    Small-scale topographic features are commonly found on the boundaries of natural rivers, streams, and floodplains. A simple method for determining the form drag on these features is presented, and the results of this model are compared to laboratory measurements. The roughness elements are modeled as Gaussian-shaped features defined in terms of three parameters: a protrusion height, H; a streamwise length scale, ??; and a spacing between crests, ??. This shape is shown to be a good approximation to a wide variety of natural topographic bank features. The form drag on an individual roughness element embedded in a series of identical elements is determined using the drag coefficient of the individual element and a reference velocity that includes the effects of roughness elements further upstream. In addition to calculating the drag on each element, the model determines the spatially averaged total stress, skin friction stress, and roughness height of the boundary. The effects of bank roughness on patterns of velocity and boundary shear stress are determined by combining the form drag model with a channel flow model. The combined model shows that drag on small-scale topographic features substantially alters the near-bank flow field. These methods can be used to improve predictions of flow resistance in rivers and to form the basis for fully predictive (no empirically adjusted parameters) channel flow models. They also provide a foundation for calculating the near-bank boundary shear stress fields necessary for determining rates of sediment transport and lateral erosion.

  6. The variation of riverbed material due to tropical storms in Shi-Wen River, Taiwan.

    PubMed

    Lin, Chin-Ping; Wang, Yu-Min; Tfwala, Samkele S; Chen, Ching-Nuo

    2014-01-01

    Taiwan, because of its location, is a flood prone region and is characterised by typhoons which brings about two-thirds to three quarters of the annual rainfall amount. Consequently, enormous flows result in rivers and entrain some fractions of the grains that constitute the riverbed. Hence, the purpose of the study is to quantify the impacts of these enormous flows on the distribution of grain size in riverbeds. The characteristics of riverbed material prior to and after the typhoon season are compared in Shi-Wen River located at southern Taiwan. These include grain size variation, bimodality, and roughness coefficient. A decrease (65%) and increase (50%) in geometric mean size of grains were observed for subsurface and surface bed material, respectively. Geometric standard deviation decreased in all sites after typhoon. Subsurface material was bimodal prior to typhoons and polymodal after. For surface material, modal class is in the gravel class, while after typhoons it shifts towards cobble class. The reduction in geometric mean resulted to a decrease in roughness coefficient by up to 30%. Finally, the relationship of Shields and Froude numbers are studied and a change in the bed form to antidunes and transition form is observed, respectively.

  7. Form drag in rivers due to small-scale natural topographic features: 2. Irregular sequences

    NASA Astrophysics Data System (ADS)

    Kean, Jason W.; Smith, J. Dungan

    2006-12-01

    The size, shape, and spacing of small-scale topographic features found on the boundaries of natural streams, rivers, and floodplains can be quite variable. Consequently, a procedure for determining the form drag on irregular sequences of different-sized topographic features is essential for calculating near-boundary flows and sediment transport. A method for carrying out such calculations is developed in this paper. This method builds on the work of Kean and Smith (2006), which describes the flow field for the simpler case of a regular sequence of identical topographic features. Both approaches model topographic features as two-dimensional elements with Gaussian-shaped cross sections defined in terms of three parameters. Field measurements of bank topography are used to show that (1) the magnitude of these shape parameters can vary greatly between adjacent topographic features and (2) the variability of these shape parameters follows a lognormal distribution. Simulations using an irregular set of topographic roughness elements show that the drag on an individual element is primarily controlled by the size and shape of the feature immediately upstream and that the spatial average of the boundary shear stress over a large set of randomly ordered elements is relatively insensitive to the sequence of the elements. In addition, a method to transform the topography of irregular surfaces into an equivalently rough surface of regularly spaced, identical topographic elements also is given. The methods described in this paper can be used to improve predictions of flow resistance in rivers as well as quantify bank roughness.

  8. Form drag in rivers due to small-scale natural topographic features: 1. Regular sequences

    NASA Astrophysics Data System (ADS)

    Kean, Jason W.; Smith, J. Dungan

    2006-12-01

    Small-scale topographic features are commonly found on the boundaries of natural rivers, streams, and floodplains. A simple method for determining the form drag on these features is presented, and the results of this model are compared to laboratory measurements. The roughness elements are modeled as Gaussian-shaped features defined in terms of three parameters: a protrusion height, H; a streamwise length scale, σ; and a spacing between crests, λ. This shape is shown to be a good approximation to a wide variety of natural topographic bank features. The form drag on an individual roughness element embedded in a series of identical elements is determined using the drag coefficient of the individual element and a reference velocity that includes the effects of roughness elements further upstream. In addition to calculating the drag on each element, the model determines the spatially averaged total stress, skin friction stress, and roughness height of the boundary. The effects of bank roughness on patterns of velocity and boundary shear stress are determined by combining the form drag model with a channel flow model. The combined model shows that drag on small-scale topographic features substantially alters the near-bank flow field. These methods can be used to improve predictions of flow resistance in rivers and to form the basis for fully predictive (no empirically adjusted parameters) channel flow models. They also provide a foundation for calculating the near-bank boundary shear stress fields necessary for determining rates of sediment transport and lateral erosion.

  9. The chemical composition of rivers and snow affected by the 2014/2015 Bárðarbunga eruption, Iceland

    NASA Astrophysics Data System (ADS)

    Galeczka, Iwona; Sigurdsson, Gunnar; Eiriksdottir, Eydis Salome; Oelkers, Eric H.; Gislason, Sigurdur R.

    2016-04-01

    The 2014/15 Bárðarbunga volcanic eruption was the largest in Iceland for more than 200 years. This eruption released into the atmosphere on average 60,000 tonnes/day of SO2, 30,000 tonnes/day of CO2, and 500 tonnes/day of HCl affecting the chemical composition of rain, snow, and surface water. The interaction of these volcanic gases with natural waters, decreases fluid pH and accelerates rock dissolution. This leads to the enhanced release of elements, including toxic metals such as aluminium, to these waters. River monitoring, including spot and continuous osmotic sampling, shows that although the water conductivity was relatively stable during the volcanic unrest, the dissolution of volcanic gases increased the SO4, F, and Cl concentrations of local surface waters by up to two orders of magnitude decreasing the carbon alkalinity. In addition the concentration of SiO2, Ca, Mg, Na and trace metals rose considerably due to the water-molten lava and hot solid lava interaction. The presence of pristine lava and acidic gases increased the average chemical denudation rate, calculated based on Na flux, within Jökulsá á Fjöllum catchment by a factor of two compared to the background flux. Melted snow samples collected at the eruption site were characterised by a strong dependence of the pH on SO4, F and Cl and metal concentrations, indicating that volcanic gases and aerosols acidified the snow. Protons balanced about half of the negatively charged anions; the rest was balanced by water-soluble salts and aerosols containing a variety of metals including Al, Fe, Na, Ca, and Mg. The concentrations of F, Al, Fe, Mn, Cd, Cu, and Pb in the snowmelt water surpassed drinking- and surface water standards. Snowmelt-river water mixing calculations indicate that low alkalinity surface waters, such as numerous salmon rivers in East Iceland, will be more affected by polluted snowmelt waters than high alkalinity spring and glacier fed rivers.

  10. The uncertainty of assessments of the water balance components of river basins due to the climate noise

    NASA Astrophysics Data System (ADS)

    Gusev, Yeugeniy; Semenov, Vladimir; Nasonova, Olga; Kovalev, Evgeny

    2016-04-01

    , simulations of the water balance components were performed by SWAP with 6-hour time step for 33 years (from 1980 to 2012) using the corrected meteorological fields. The simulated 45 evolutions of the water balance components of the river basins allowed us to estimate their average trajectories (which showed a good agreement with observations) and their uncertainty on different time scales (annual and monthly) due to climate noise. The obtained results showed that monthly uncertainties for all water balance components are higher than annual ones. Besides that the larger a river basin, the less the uncertainties in the estimates of the water balance components. In addition, the spectral densities of the water balance components were calculated for the river basins. It was shown that a river basin filters high-frequency components of precipitation (corresponding to synoptic or some more scale) during the transformation of precipitation into evapotranspiration and especially into river runoff.

  11. Mercury accumulation in sediment and fish from rivers affected by alluvial gold mining in the Brazilian Madeira River basin, Amazon.

    PubMed

    Reuther, R

    1994-09-01

    The degree and distribution of mercury (Hg) accumulation in sediment and fish from a tributary affected by alluvial small-scale gold mining in the Madeira River/Amazon is studied, in relation to a reference site. The results obtained so far agree well with previous studies and confirm that a tremendous contamination of main food web compartments occurs in these highly exposed, but vulnerable tropical waters. An essential part of the released metallic Hg may still exist as macroscopic liquid Hg drops in the sediment. Both global (0.4 mg/kg of Hg) and local (0.1 mg/kg of Hg) background sediment values as well as safety levels for fish (0.5 mg/kg of Hg) are considerably exceeded by a factor of up to 25, 100, and 4, respectively, and give rise to serious concern, not least with regard to the formation of the very toxic monomethyl-Hg. It is further discussed that atmospheric transport and deposition of Hg in water reservoirs built for hydroelectric power generation may act as critical pathways for longterm Hg accumulation, even in unexposed riverine systems.

  12. Do predator-prey relationships on the river bed affect fine sediment ingress?

    NASA Astrophysics Data System (ADS)

    Mathers, Kate; Rice, Stephen; Wood, Paul

    2016-04-01

    Ecosystem engineers are organisms that alter their physical environment and thereby influence the flow of resources through ecosystems. In rivers, several ecosystem engineers are also important geomorphological agents that modify fluvial sediment dynamics. By altering channel morphology and bed material characteristics, such modifications can affect the availability of habitats for other organisms, with implications for ecosystem health and wider community composition. In this way geomorphological and ecological systems are intimately interconnected. This paper focuses on one element of this intricate abiotic-biotic coupling: the interaction between fine sediment ingress into the river bed and the predator-prey relationships of aquatic organisms living on and in the river bed. Signal crayfish (Pacifastacus leniusculus) have been shown to modify fine sediment fluxes in rivers, but their effect on fine sediment ingress into riverbeds remains unclear. Many macroinvertebrate taxa have adapted avoidance strategies to avoid predation by crayfish, with one example being the freshwater shrimp (Gammarus pulex) which relies on open interstitial spaces within subsurface sediments as a refuge from crayfish predation. Fine sedimentation that fills gravelly frameworks may preclude access to those spaces, therefore leaving freshwater shrimp susceptible to predation. Ex-situ experiments were conducted which sought to examine: i) if freshwater shrimps and signal crayfish, alone and in combination, influenced fine sediment infiltration rates; and ii) whether modifications to substratum composition, specifically the introduction of fine sediment, modified predator-prey interactions. The results demonstrate that crayfish are significant geomorphic agents and that fine sediment ingress rates were significantly enhanced in their presence compared to control conditions or the presence of only freshwater shrimps. The combination of both organisms (i.e. allowing the interaction between

  13. Soils affected by heavy metals due to old mining on perudic conditions

    NASA Astrophysics Data System (ADS)

    Garrigo, Jordi; Elustondo, David; Laheras, Ester; Oiarzabal, Maite; Jaume, Bech

    2010-05-01

    The aim of this work is to assess the actual status of the soils of a natural environment surrounding an abandoned mine (exploited since the Roman Age) where Pb, Zn, Fe and Cu were obtained. The study has been carried out in the Aitzondo valley (Guipuzkoa, North of Iberian Peninsula), which cross the exploited mountainous area with middle temperatures and perudic soil moisture regime Soils in the valley are polygenic, acids, very washed and sometimes show redoximorphic features and have undergone a great mobilization of trace metals due to these physical-chemical characteristics that enhance the heavy metals solubility and mobility. The analysis of soil surface samples shows a punctual and intense pollution at Meazuri area (where the mine is located) and another more dispersal and wide pollution due to the parent material (Palaeozoic shales). The main soil type of the area has been characterized by means of the performance of a soil and six surface samples have been collected along an altitudinal transect, which goes down from 460 to 75 meters. Both profile and surface samples have been analysed for suitable parameters due to their repercussion in mobility and fixation of some heavy metals (organic matter, clay content…). Total (Na, K, Mg, Ca, Al, Fe, Mn, Ti, Cd, Cr) and extractable fraction (using NH4Ac-EDTA pH=4.65, as extracting agent, have been analysed. Trace elements Cd, Cr, Cu, Ni, Pb and Zn have been measured. On summary, the soils studied are characterized by high levels of trace metals inherited from the parent material whose composition shows a great metallic richness. Hence, values of trace metals are very high even in remote areas where there has not been anthropic influence. Besides, the physical-chemical properties (acidity, base saturation, organic matter) have enhanced the mobility of trace metals. The anthropogenic activity (mining activity) has caused an increase in values of several metals, reaching, in some cases, concentrations above the

  14. Real-time Monitoring Network to Characterize Anthropogenic and Natural Events Affecting the Hudson River, NY

    NASA Astrophysics Data System (ADS)

    Islam, M. S.; Bonner, J. S.; Fuller, C.; Kirkey, W.; Ojo, T.

    2011-12-01

    transition region between fresh and saline water, captured the occurrence of strong precipitation event on the Hudson river as indicated by reduced water column salinity levels in the water column. Despite the large influx of freshwater and suspended solids originating as precipitation runoff, tidal forces dominated the net water transport and coincident suspended particle load. Such information is crucial to track the particle-driven contaminant movement in the water column. Both the FRVP and MRUP have been deployed in an active Poly-Chlorinated Biphenyls Superfund site to characterize the fundamental sediment transport mechanisms affecting remedial dredging operations. A potential application of this monitoring system is in the development of an adaptive remedial operation, where activity would be adjusted to maintain conditions within threshold limits based on real time environmental observations. Further, observational REON data can be integrated with water quality and hydrodynamic models that can be used to evaluate episodic events and their subsequent impacts to the Hudson River.

  15. Heavy metals in potable groundwater of mining-affected river catchments, northwestern Romania.

    PubMed

    Bird, Graham; Macklin, Mark G; Brewer, Paul A; Zaharia, Sorin; Balteanu, Dan; Driga, Basarab; Serban, Mihaela

    2009-12-01

    Groundwater, accessed using wells and municipal springs, represents the major source of potable water for the human population outside of major urban areas in northwestern Romania, a region with a long history of metal mining and metallurgy. The magnitude and spatial distribution of metal contamination in private-supply groundwater was investigated in four mining-affected river catchments in Maramureş and Satu Mare Counties through the collection of 144 groundwater samples. Bedrock geology, pH and Eh were found to be important controls on the solubility of metals in groundwater. Peak metal concentrations were found to occur in the Lapuş catchment, where metal levels exceed Dutch target and intervention values in up to 49% and 14% of samples, respectively. A 700 m wide corridor in the Lapuş catchment on either side of the main river channel was identified in which peak Cd (31 μg l(-1)), Cu (50 μg l(-1)), Pb (50 μg l(-1)) and Zn (3,000 μg l(-1)) concentrations were found to occur. Given the generally similar bedrock geologies, lower metal levels in other catchments are believed to reflect differences in the magnitude of metal loading to the local environment from both metal mining and other industrial and municipal sources. Sampling of groundwater in northwestern Romania has indicated areas of potential concern for human health, where heavy metal concentrations exceed accepted environmental quality guidelines. The presence of elevated metal levels in groundwater also has implications for the implementation of the EU Water Framework Directive (WFD) and achieving 'good' status for groundwater in this part of the Danube River Basin District (RBD).

  16. Groundwater contributions to metal transport in a small river affected by mining and smelting waste.

    PubMed

    Coynel, Alexandra; Schäfer, Jörg; Dabrin, Aymeric; Girardot, Naïg; Blanc, Gérard

    2007-08-01

    The Riou Mort watershed, strongly affected by former coal mining and Zn ore treatment, has been the major source of the historical polymetallic pollution of the Lot-Garonne-Gironde fluvial-estuarine system. Two decades after the end of ore treatment, the former industrial area still contributes important amounts of metals/metalloids from various, partly unidentified, sources to the downstream river system. This study presents the high spatial variability of metal/metalloid (Cd, Zn, As, Sb, U, V) concentrations in water and suspended particulate matter (SPM) from eight observation sites during a short, intense flood event. Despite important dilution effects, the observed concentration levels at the different sites suggested additional Cd and Zn inputs, probably from polluted groundwater. This formerly unknown metal source was then localized and characterized by sampling water and SPM along two longitudinal profiles during different hydrological situations. Groundwater inputs of "truly dissolved" (<0.02 microm) Cd and Zn occurred along approximately 200 m, contributing 43% and 28% to the total annual (2004) Cd and Zn fluxes in the Riou Mort River. The estimated groundwater concentrations of Cd and Zn (2500-6700 and 83,000-170,000 microg l(-1), respectively) in the source zone were consistent with values measured in samples from the near aquifer (5400-13,000 and 200,000-400,000 microg l(-1)). The present work induced concrete remediation actions (pumping and treatment of the polluted groundwater), that are expected to strongly reduce dissolved Cd and Zn emissions into the Riou Mort River.

  17. Effects of combined sewer overflow and stormwater on indicator bacteria concentrations in the Tama River due to the high population density of Tokyo Metropolitan area.

    PubMed

    Ham, Young-Sik; Kobori, Hiromi; Takasago, Masahisa

    2009-05-01

    The indicator bacteria (standard plate count, total coliform, and fecal coliform bacteria) concentrations have been investigated using six ambient habitats (population density, percent sewer penetration, stream flow rate (m(3)/sec), percent residential area, percent forest area and percent agricultural area) in the Tama River basin in Tokyo, Japan during June 2003 to January 2005. The downstream and tributary Tama River showed higher concentrations of TC and FC bacteria than the upstream waters, which exceeded an environmental quality standard for rivers and a bathing water quality criterion. It was estimated that combined sewer overflow (CSO) and stormwater effluents contributed -4-23% to the indicator bacteria concentrations of the Tama River. The results of multiple regression analyses show that the indicator bacteria concentrations of Tama River basin are significantly affected by population density. It is concluded that the Tama River received a significant bacterial contamination load originating from the anthropogenic source.

  18. Water quality and processes affecting dissolved oxygen concentrations in the Blackwater River, Canaan Valley, West Virginia

    USGS Publications Warehouse

    Waldron, M.C.; Wiley, J.B.

    1996-01-01

    The water quality and environmental processes affecting dissolved oxygen were determined for the Blackwater River in Canaan Valley, West Virginia. Canaan Valley is oval-shaped (14 miles by 5 miles) and is located in the Allegheny Mountains at an average elevation of 3,200 feet above sea level. Tourism, population, and real estate development have increased in the past two decades. Most streams in Canaan Valley are a dilute calcium magnesium bicarbonate-type water. Streamwater typicaly was soft and low in alkalinity and dissolved solids. Maximum values for specific conductance, hardness, alkalinity, and dissolved solids occurred during low-flow periods when streamflow was at or near baseflow. Dissolved oxygen concentrations are most sensitive to processes affecting the rate of reaeration. The reaeration is affected by solubility (atmospheric pressure, water temperature, humidity, and cloud cover) and processes that determine stream turbulence (stream depth, width, velocity, and roughness). In the headwaters, photosynthetic dissolved oxygen production by benthic algae can result in supersaturated dissolved oxygen concentrations. In beaver pools, dissolved oxygen consumption from sediment oxygen demand and carbonaceous biochemical oxygen demand can result in dissolved oxygen deficits.

  19. Verification of Precipitation Enhancement due to Winter Orographic Cloud Seeding in the Payette River Basin of Western Idaho

    NASA Astrophysics Data System (ADS)

    Holbrook, V. P.; Kunkel, M. L.; Blestrud, D.

    2013-12-01

    The Idaho Power Company (IPCo) is a hydroelectric based utility serving eastern Oregon and most of southern Idaho. Snowpack is critical to IPCo operations and the company has invested in a winter orographic cloud seeding program for the Payette, Boise, and Upper Snake River basins to augment the snowpack. IPCo and the National Center for Atmospheric Research (NCAR) are in the middle of a two-year study to determine precipitation enhancement due to winter orographic cloud seeding in the Payette River basin. NCAR developed a cloud seeding module, as an enhancement to the Weather Research and Forecast (WRF) model, that inputs silver iodide released from both ground based and/or aircraft generators. The cloud seeding module then increases the precipitation as a function of the cloud seeding. The WRF model used for this program is run at the University of Arizona with a resolution of 1.8 kilometers using Thompson microphysics and Mellor-Yamada-Janic boundary layer scheme. Two different types of verification schemes to determine precipitation enhancement is being used for this program; model versus model and model versus precipitation gauges. In the model versus model method, a control model run uses NCAR developed criteria to identify the best times to operate cloud or airborne seeding generators and also establishes the baseline precipitation. The model is then rerun with the cloud seeding module turned on for the time periods determined by the control run. The precipitation enhancement due to cloud seeding is then the difference in precipitation between the control and seeding model runs. The second verification method is to use the model forecast precipitation in the seeded and non-seeded areas, compare against observed precipitation (from mainly SNOTEL gauges), and determine the precipitation enhancement due to cloud seeding. Up to 15 SNOTEL gauges in or near the Payette River basin along with 14 IPCo high resolution rain gauges will be used with this target

  20. Hydrologic alteration affects aquatic plant assemblages in an arid-land river

    USGS Publications Warehouse

    Vinson, Mark; Hestmark, Bennett; Barkworth, Mary E.

    2014-01-01

    We evaluated the effects of long-term flow alteration on primary-producer assemblages. In 1962, Flaming Gorge Dam was constructed on the Green River. The Yampa River has remained an unregulated hydrologically variable river that joins the Green River 100 km downstream from Flaming Gorge Dam. In the 1960s before dam construction only sparse occurrences of two macroalgae, Cladophora and Chara, and no submerged vascular plants were recorded in the Green and Yampa rivers. In 2009–2010, aquatic plants were abundant and widespread in the Green River from the dam downstream to the confluence with the Yampa River. The assemblage consisted of six vascular species, Elodea canadensis, Myriophyllum sibiricum, Nasturtium officinale,Potamogeton crispus, Potamogeton pectinatus, and Ranunculus aquatilis, the macroalgae Chara and Cladophora, and the bryophyte, Amblystegium riparium. In the Green River downstream from the Yampa River, and in the Yampa River, only sparse patches of Chara and Cladophora growing in the splash zone on boulders were collected. We attribute the observed changes in the Green River to an increase in water transparency and a reduction in suspended and bed-load sediment and high flow disturbances. The lack of hydrophyte colonization downstream from the confluence with the Yampa River has implications for understanding tributary amelioration of dam effects and for designing more natural flow-regime schedules downstream from large dams.

  1. Incipient motion in gravel bed rivers due to energetic turbulent flow events

    NASA Astrophysics Data System (ADS)

    Valyrakis, Manousos

    2013-04-01

    This contribution reviews recent developments and contributions in the field of incipient motion and entrainment of coarse sediment grains due to the action of near bed turbulent flows. Specifically, traditional shear based spatio-temporally averaged concepts and instantaneous stress tensor criteria are contrasted to the newly proposed flow event based impulse and energy criteria. The energy criterion, suggests that only sufficiently energetic turbulent events can remove a particle from its resting position on the bed surface and result on its entrainment downstream. While the impulse and energy criteria are interconnected through the energy-impulse equation, the later appears to be more versatile and appropriate for generalising to sediment transport. These flow event based criteria have a sound physical basis for describing the intermittent character of particle entrainment as inherited by near boundary turbulence at near threshold conditions. These criteria can be derived from fundamental laws of physics such as Newtonian classical mechanics and the Lagrange equations respectively. The energetic events that are capable of performing geomorphic work at the scale of individual particles are shown to follow a power law, meaning that more energetic events (capable of removing larger stones) are expected to occur less frequently. In addition, this paper discusses the role of the coefficient of energy transfer efficiency introduced in the energy equation for particle entrainment. A preliminary investigation from analysis of a series of mobile grain flume experiments illustrates that different signatures of turbulence or sequence of flow structures may have different effectiveness towards particle transport. Characteristic cases of specific energetic flow events and the associated particle response are shown and classified with regard to the time required for complete entrainment. Finally these findings are commented with respect to the implications for sediment

  2. Morphodynamics of rivers strongly affected by monsoon precipitation: Review of depositional style and forcing factors

    NASA Astrophysics Data System (ADS)

    Plink-Björklund, Piret

    2015-06-01

    Rivers that receive significant amounts of their surface water supply from monsoon precipitation characteristically experience seasonal floods, and display seasonally highly variable discharge, controlled by the monsoon trough passage and its related cyclones. The intense summer rainfall causes high-magnitude floods, whereas rivers only transmit a low base flow during the dry winters. For many rivers in the sub-humid to arid subtropics, bordering the monsoon domain, the monsoon rain is also the main source of surface water recharge. However, such rivers may receive monsoon rain and transmit discharge only during abnormal or strengthened monsoon seasons. This annual discharge variability or range, as compared to the mean annual discharge, distinguishes the monsoonal and subtropical rivers from the rivers in equatorial tropics and temperate perennial precipitation zones, where the annual range is relatively small compared to the annual mean discharge. This review explores the effects of this seasonal and yearly variable rainfall, and the resultant highly peaked discharge pattern on river morphodynamics, and presents a comparison of modern and ancient monsoonal and subtropical river deposits. The field datasets and literature analyses discussed herein provide recognition criteria for monsoon-controlled river deposits, by documenting the diversity of the sedimentary facies, macroforms (bar forms), and architectural elements common in ancient and modern monsoon-controlled rivers. The review demonstrates that seasonal and inter-annual precipitation range is a key control on river morphodynamics, and resultant sedimentary facies characteristics, rather than the specific climate zone or average annual precipitation.

  3. Modelling evolution of air dose rates in river basins in Fukushima Prefecture affected by sediment-sorbed radiocesium redistribution

    NASA Astrophysics Data System (ADS)

    Malins, A.; Sakuma, K.; Nakanishi, T.; Kurikami, H.; Machida, M.; Kitamura, A.; Yamada, S.

    2015-12-01

    The radioactive 134Cs and 137Cs isotopes deposited over Fukushima Prefecture by the Fukushima Daiichi nuclear disaster are the predominant radiological concern for the years following the accident. This is because the energetic gamma radiation they emit on decay constitutes the majority of the elevated air dose rates that now afflict the region. Therefore, we developed a tool for calculating air dose rates from arbitrary radiocesium spatial distributions across the land surface and depth profiles within the ground. As cesium is strongly absorbed by clay soils, its primary redistribution mechanism within Fukushima Prefecture is by soil erosion and water-borne sediment transport. Each year between 0.1~1% of the total radiocesium inventory in the river basins neighboring Fukushima Daiichi is eroded from the land surface and enters into water courses, predominantly during typhoon storms. Although this is a small amount in relative terms, in absolute terms it corresponds to terabecquerels of 134Cs and 137Cs redistribution each year and this can affect the air dose rate at locations of high erosion and sediment deposition. This study inputs the results of sediment redistribution simulations into the dose rate evaluation tool to calculate the locations and magnitude of air dose rate changes due to radiocesium redistribution. The dose rate calculations are supported by handheld survey instrument results taken within the Prefecture.

  4. The risk of river pollution due to washout from contaminated floodplain water bodies during periods of high magnitude floods

    NASA Astrophysics Data System (ADS)

    Lyubimova, T.; Lepikhin, A.; Parshakova, Ya.; Tiunov, A.

    2016-03-01

    The risk of river pollution due to washout (removal of pollutants) from contaminated floodplain water bodies (floodplain lakes and quarries whose origin is related to the large-scale mining of nonmetallic building materials in the floodplain zone) during high magnitude flood periods is analyzed using a combination of one-, two- and three-dimensional hydrodynamic modeling and in situ measurements. The modeling performed for the floodplain water bodies contaminated by N compounds shows that during large magnitude floods washout occurs. The washout process consists of two stages: an initial rapid stage lasting about two hours during which the upper (3-4 m thick) layer is washed out, followed by a second stage when the concentration of NH4-N in the floodplain water body remains nearly constant. The maximum contaminant concentration in the river in the vicinity of a water intake for drinking water located 21 km downstream is attained about 9 h from the beginning of the flood; concentration of NH4-N can reach values several times larger than acceptable concentration guidelines. The initial primary peak in contaminant concentration at the water intake is followed by a slight decrease in contaminant concentration; a second peak related to the contaminant transport through the inundated floodplain subsequently occurs, after which the concentration slowly decreases, reaching acceptable values after 30-40 h. Contaminated floodplain water bodies located near drinking water supply systems are not significant sources of contamination during small and moderate floods, but during high magnitude floods, they can become sources of water pollution. Operational measures that can decrease potential health risks are discussed.

  5. Uncertainty in flow and sediment projections due to future climate scenarios for the 3S Rivers in the Mekong Basin

    NASA Astrophysics Data System (ADS)

    Shrestha, Bikesh; Cochrane, Thomas A.; Caruso, Brian S.; Arias, Mauricio E.; Piman, Thanapon

    2016-09-01

    Reliable projections of discharge and sediment are essential for future water and sediment management plans under climate change, but these are subject to numerous uncertainties. This study assessed the uncertainty in flow and sediment projections using the Soil and Water Assessment Tool (SWAT) associated with three Global Climate Models (GCMs), three Representative Concentration Pathways (RCPs) and three model parameter (MP) sets for the 3S Rivers in the Mekong River Basin. The uncertainty was analyzed for the short term future (2021-2040 or 2030s) and long term future (2051-2070 or 2060s) time horizons. Results show that dominant sources of uncertainty in flow and sediment constituents vary spatially across the 3S basin. For peak flow, peak sediment, and wet seasonal flows projection, the greatest uncertainty sources also vary with time horizon. For 95% low flows and for seasonal and annual flow projections, GCM and MP were the major sources of uncertainty, whereas RCPs had less of an effect. The uncertainty due to RCPs is large for annual sediment load projections. While model parameterization is the major source of uncertainty in the short term (2030s), GCMs and RCPs are the major contributors to uncertainty in flow and sediment projections in the longer term (2060s). Overall, the uncertainty in sediment load projections is larger than the uncertainty in flow projections. In general, our results suggest the need to investigate the major contributing sources of uncertainty in large basins temporally and at different scales, as this can have major consequences for water and sediment management decisions. Further, since model parameterization uncertainty can play a significant role for flow and sediment projections, there is a need to incorporate hydrological model parameter uncertainty in climate change studies and efforts to reduce the parameter uncertainty as much as possible should be considered through a careful calibration and validation process.

  6. Satellite-based investigation of flood-affected rice cultivation areas in Chao Phraya River Delta, Thailand

    NASA Astrophysics Data System (ADS)

    Son, N. T.; Chen, C. F.; Chen, C. R.; Chang, L. Y.

    2013-12-01

    The occurrence of catastrophic floods in Thailand in 2011 caused significant damage to rice agriculture. This study investigated flood-affected rice cultivation areas in the Chao Phraya River Delta (CRD) rice bowl, Thailand using time-series moderate resolution imaging spectroradiometer (MODIS) data. The data were processed for 2008 (normal flood year) and 2011, comprising four main steps: (1) data pre-processing to construct time-series MODIS vegetation indices (VIs), to filter noise from the time-series VIs by the empirical mode decomposition (EMD), and to mask out non-agricultural areas in respect to water-related cropping areas; (2) flood-affected area classification using the unsupervised linear mixture model (ULMM); (3) rice crop classification using the support vector machines (SVM); and (4) accuracy assessment of flood and rice crop mapping results. The comparisons between the flood mapping results and the ground reference data indicated an overall accuracy of 97.9% and Kappa coefficient of 0.62 achieved for 2008, and 95.7% and 0.77 for 2011, respectively. These results were reaffirmed by close agreement (R2 > 0.8) between comparisons of the two datasets at the provincial level. The crop mapping results compared with the ground reference data revealed that the overall accuracies and Kappa coefficients obtained for 2008 were 88.5% and 0.82, and for 2011 were 84.1% and 0.76, respectively. A strong correlation was also found between MODIS-derived rice area and rice area statistics at the provincial level (R2 > 0.7). Rice crop maps overlaid on the flood-affected area maps showed that approximately 16.8% of the rice cultivation area was affected by floods in 2011 compared to 4.9% in 2008. A majority of the flood-expanded area was observed for the double-cropped rice (10.5%), probably due to flood-induced effects to the autumn-summer and rainy season crops. Information achieved from this study could be useful for agricultural planners to mitigate possible impacts

  7. Identification of key factors affecting the water pollutant concentration in the sluice-controlled river reaches of the Shaying River in China via statistical analysis methods.

    PubMed

    Dou, Ming; Zhang, Yan; Zuo, Qiting; Mi, Qingbin

    2015-08-01

    The construction of sluices creates a strong disturbance in water environmental factors within a river. The change in water pollutant concentrations of sluice-controlled river reaches (SCRRs) is more complex than that of natural river segments. To determine the key factors affecting water pollutant concentration changes in SCRRs, river reaches near the Huaidian Sluice in the Shaying River of China were selected as a case study, and water quality monitoring experiments based on different regulating modes were implemented in 2009 and 2010. To identify the key factors affecting the change rates for the chemical oxygen demand of permanganate (CODMn) and ammonia nitrogen (NH3-N) concentrations in the SCRRs of the Huaidian Sluice, partial correlation analysis, principal component analysis and principal factor analysis were used. The results indicate four factors, i.e., the inflow quantity from upper reaches, opening size of sluice gates, water pollutant concentration from upper reaches, and turbidity before the sluice, which are the common key factors for the CODMn and NH3-N concentration change rates. Moreover, the dissolved oxygen before a sluice is a key factor for the permanganate concentration from CODMn change rate, and the water depth before a sluice is a key factor for the NH3-N concentration change rate. Multiple linear regressions between the water pollutant concentration change rate and key factors were established via multiple linear regression analyses, and the quantitative relationship between the CODMn and NH3-N concentration change rates and key affecting factors was analyzed. Finally, the mechanism of action for the key factors affecting the water pollutant concentration changes was analyzed. The results reveal that the inflow quantity from upper reaches, opening size of sluice gates, permanganate concentration from CODMn from upper reaches and dissolved oxygen before the sluice have a negative influence and the turbidity before the sluice has a positive

  8. [Spatiotemporal variation characteristics and related affecting factors of actual evapotranspiration in the Hun-Taizi River Basin, Northeast China].

    PubMed

    Feng, Xue; Cai, Yan-Cong; Guan, De-Xin; Jin, Chang-Jie; Wang, An-Zhi; Wu, Jia-Bing; Yuan, Feng-Hui

    2014-10-01

    Based on the meteorological and hydrological data from 1970 to 2006, the advection-aridity (AA) model with calibrated parameters was used to calculate evapotranspiration in the Hun-Taizi River Basin in Northeast China. The original parameter of the AA model was tuned according to the water balance method and then four subbasins were selected to validate. Spatiotemporal variation characteristics of evapotranspiration and related affecting factors were analyzed using the methods of linear trend analysis, moving average, kriging interpolation and sensitivity analysis. The results showed that the empirical parameter value of 0.75 of AA model was suitable for the Hun-Taizi River Basin with an error of 11.4%. In the Hun-Taizi River Basin, the average annual actual evapotranspiration was 347.4 mm, which had a slightly upward trend with a rate of 1.58 mm · (10 a(-1)), but did not change significantly. It also indicated that the annual actual evapotranspiration presented a single-peaked pattern and its peak value occurred in July; the evapotranspiration in summer was higher than in spring and autumn, and it was the smallest in winter. The annual average evapotranspiration showed a decreasing trend from the northwest to the southeast in the Hun-Taizi River Basin from 1970 to 2006 with minor differences. Net radiation was largely responsible for the change of actual evapotranspiration in the Hun-Taizi River Basin. PMID:25796880

  9. Geographic information science: Contribution to understanding salt and sodium affected soils in the Senegal River Valley

    NASA Astrophysics Data System (ADS)

    Ndiaye, Ramatoulaye

    The Senegal River valley and delta (SRVD) are affected by long term climate variability. Indicators of these climatic shifts include a rainfall deficit, warmer temperatures, sea level rise, floods, and drought. These shifts have led to environmental degradation, water deficits, and profound effects on human life and activities in the area. Geographic Information Science (GIScience), including satellite-based remote sensing methods offer several advantages over conventional ground-based methods used to map and monitor salt-affected soil (SAS) features. This study was designed to assess the accuracy of information on soil salinization extracted from Landsat satellite imagery. Would available imagery and GIScience data analysis enable an ability to discriminate natural soil salinization from soil sodication and provide an ability to characterize the SAS trend and pattern over 30 years? A set of Landsat MSS (June 1973 and September 1979), Landsat TM (November 1987, April 1994 and November 1999) and ETM+ (May 2001 and March 2003) images have been used to map and monitor salt impacted soil distribution. Supervised classification, unsupervised classification and post-classification change detection methods were used. Supervised classifications of May 2001 and March 2003 images were made in conjunction field data characterizing soil surface chemical characteristics that included exchange sodium percentage (ESP), cation exchange capacity (CEC) and the electrical conductivity (EC). With this supervised information extraction method, the distribution of three different types of SAS (saline, saline-sodic, and sodic) was mapped with an accuracy of 91.07% for 2001 image and 73.21% for 2003 image. Change detection results confirmed a decreasing trend in non-saline and saline soil and an increase in saline-sodic and sodic soil. All seven Landsat images were subjected to the unsupervised classification method which resulted in maps that separate SAS according to their degree of

  10. Analysis on radiocesium concentration in rivers that have catchment areas affected by the fallout from Fukushima Daiichi Nuclear Power Plant

    NASA Astrophysics Data System (ADS)

    Taniguchi, Keisuke; Yoshimura, Kazuya; Sakaguchi, Aya; Yamamoto, Masayoshi; Onda, Yuichi

    2014-05-01

    Due to Fukushima Daiichi Nuclear Power Plant accident, radioactive materials including Cs-134 and Cs-137 were widely distributed in surrounded area. The radiocesiums have been transported in river networks. This study showed the monitoring results of radiocesium concentration in river waters and suspended sediments in Abukuma river basin and smaller coastal river catchments. The monitoring started at 6 sites from June 2011. Subsequently, additional 24 monitoring sites were installed between October 2012 and January 2013. Flow and turbidity (for calculation of suspended sediment concentration) were measured at each site, while suspended sediments and river water were collected every one or half month to measure Cs-134 and Cs-137 activity concentrations by gamma spectrometry. Activity concentrations of Cs-134 and Cs- 137 on suspended sediments were generally decreasing at all sites. The decreasing rate changed lower at about one year later from the accident. Activity concentration in river waters also showed the same tendency although there are only few data within 1 year from the accident. Activity concentrations measured at the same day are proportional to the mean catchment inventory. Therefore, the activity concentration can be normalized by the mean catchment inventory. The normalized activity can be fitted to following double exponential function: [At] = 1.551 exp (-5.265t) + 0.069 exp (-0.266 t), where t [year] is the time from the accident. There is no time evolution of Kd between suspended sediments and river water. Instead, Kd was varied spatially. Although the reason of the spatial variation is not clear for now, geology of the catchment (i.e. mineral composition of suspended particles) seems to relate to the variation.

  11. Mercury Contamination in an Indicator Fish Species from Andean Amazonian Rivers Affected by Petroleum Extraction.

    PubMed

    Webb, Jena; Coomes, Oliver T; Mainville, Nicolas; Mergler, Donna

    2015-09-01

    Elevated mercury (Hg) concentrations in fish from Amazonia have been associated with gold-mining, hydroelectric dams and deforestation but few studies consider the role of petroleum extraction. Hg levels were determined in fish samples collected in three river basins in Ecuador and Peru with contrasting petroleum exploitation and land-use characteristics. The non-migratory, piscivorous species, Hoplias malabaricus, was used as a bioindicator. The rate of Hg increase with body weight for this species was significantly higher on the Corrientes River, near the site of a recent oil spill, than on the other two rivers. In the absence of substantial deforestation and other anthropogenic sources in the Corrientes River basin, this finding suggests that oil contamination in Andean Amazonia may have a significant impact on Hg levels in fish. PMID:26205230

  12. Mercury Contamination in an Indicator Fish Species from Andean Amazonian Rivers Affected by Petroleum Extraction.

    PubMed

    Webb, Jena; Coomes, Oliver T; Mainville, Nicolas; Mergler, Donna

    2015-09-01

    Elevated mercury (Hg) concentrations in fish from Amazonia have been associated with gold-mining, hydroelectric dams and deforestation but few studies consider the role of petroleum extraction. Hg levels were determined in fish samples collected in three river basins in Ecuador and Peru with contrasting petroleum exploitation and land-use characteristics. The non-migratory, piscivorous species, Hoplias malabaricus, was used as a bioindicator. The rate of Hg increase with body weight for this species was significantly higher on the Corrientes River, near the site of a recent oil spill, than on the other two rivers. In the absence of substantial deforestation and other anthropogenic sources in the Corrientes River basin, this finding suggests that oil contamination in Andean Amazonia may have a significant impact on Hg levels in fish.

  13. Elevated cadmium concentrations in potato tubers due to irrigation with river water contaminated by mining in Potosí, Bolivia.

    PubMed

    Oporto, Carla; Vandecasteele, Carlo; Smolders, Erik

    2007-01-01

    Risk of cadmium (Cd) in the human food chain in Cd-contaminated areas is often limited by phytotoxicity from zinc (Zn) that is associated with the Cd contamination. A semiarid area, 60 km downstream of a tin mine in Bolivia, was surveyed where irrigation with Cd-contaminated river water (65-240 microg Cd L(-1)) has increased median soil Cd to 20 mg kg(-1) while median soil Zn was only about 260 mg kg(-1). Cadmium concentrations in potato tubers increased from background values (0.05 mg kg(-1) dry wt.) in soils irrigated with spring water to a median value of 1.2 mg kg(-1) dry wt. in the affected area. Median concentration of Cd in soil solutions was 27 microg L(-1) and exceeded the corresponding value of Zn almost twofold. Soil-extractable chloride ranged from 40 to 1600 mg Cl(-) kg(-1) and was positively correlated with soil total Cd. Increasing soil solution Cl(-) decreased the solid-liquid distribution coefficient of Cd in soil. Soil total Cd explained 64% of the variation of tuber Cd concentration while only 3% of the variation was explained by soil extractable Cl(-) (n = 49). The estimated dietary Cd intake from potato consumption by the local population is about 100 microg d(-1) which exceeds the WHO recommended total daily intake. It is concluded that the food chain risk of Cd in the irrigation water of the semiarid area is aggravated by the association with Cl(-) and, potentially, by the relatively large Cd/Zn ratio. PMID:17596627

  14. Sulfate migration in a river affected by acid mine drainage from the Dabaoshan mining area, South China.

    PubMed

    Chen, Meiqin; Lu, Guining; Guo, Chuling; Yang, Chengfang; Wu, Jingxiong; Huang, Weilin; Yee, Nathan; Dang, Zhi

    2015-01-01

    Sulfate, a major component of acid mine drainage (AMD), its migration in an AMD-affected river which located at the Dabaoshan mine area of South China was investigated to pursue the remediation strategy. The existing factors of relatively low pH values of 2.8-3.9, high concentrations of SO4(2-) (∼1940 mg L(-1)) and Fe(3+) (∼112 mg L(-1)) facilitated the precipitation of schwertmannite (Fe8O8(OH)6SO4·nH2O) in the upstream river. Geochemical model calculations implied the river waters were supersaturated, creating the potential for precipitation of iron oxyhydroxides. These minerals evolved from schwertmannite to goethite with the increasing pH from 2.8 to 5.8 along the river. The concentration of heavy metals in river waters was great reduced as a result of precipitation effects. The large size of the exchangeable sulfate pool suggested that the sediments had a strong capacity to bind SO4(2-). The XRD results indicated that schwertmannite was the predominant form of sulfate-bearing mineral phases, which was likely to act as a major sulfate sink by incorporating water-borne sulfate into its internal structure and adsorbing it onto its surface. The small size of reduced sulfur pools and strong oxidative status in the surface sediments further showed that SO4(2-) shifting from water to sediment in form of sulfate reduction was not activated. In short, precipitation of sulfate-rich iron oxyhydroxides and subsequent SO4(2-) adsorption on these minerals as well as water dilution contributed to the attenuation of SO4(2-) along the river waters. PMID:25189685

  15. Sulfate migration in a river affected by acid mine drainage from the Dabaoshan mining area, South China.

    PubMed

    Chen, Meiqin; Lu, Guining; Guo, Chuling; Yang, Chengfang; Wu, Jingxiong; Huang, Weilin; Yee, Nathan; Dang, Zhi

    2015-01-01

    Sulfate, a major component of acid mine drainage (AMD), its migration in an AMD-affected river which located at the Dabaoshan mine area of South China was investigated to pursue the remediation strategy. The existing factors of relatively low pH values of 2.8-3.9, high concentrations of SO4(2-) (∼1940 mg L(-1)) and Fe(3+) (∼112 mg L(-1)) facilitated the precipitation of schwertmannite (Fe8O8(OH)6SO4·nH2O) in the upstream river. Geochemical model calculations implied the river waters were supersaturated, creating the potential for precipitation of iron oxyhydroxides. These minerals evolved from schwertmannite to goethite with the increasing pH from 2.8 to 5.8 along the river. The concentration of heavy metals in river waters was great reduced as a result of precipitation effects. The large size of the exchangeable sulfate pool suggested that the sediments had a strong capacity to bind SO4(2-). The XRD results indicated that schwertmannite was the predominant form of sulfate-bearing mineral phases, which was likely to act as a major sulfate sink by incorporating water-borne sulfate into its internal structure and adsorbing it onto its surface. The small size of reduced sulfur pools and strong oxidative status in the surface sediments further showed that SO4(2-) shifting from water to sediment in form of sulfate reduction was not activated. In short, precipitation of sulfate-rich iron oxyhydroxides and subsequent SO4(2-) adsorption on these minerals as well as water dilution contributed to the attenuation of SO4(2-) along the river waters.

  16. Factors affecting stranding of juvenile salmonids by wakes from ship passage in the Lower Columbia River

    SciTech Connect

    Pearson, Walter H.; Skalski, John R.

    2011-09-01

    The effects of deep-draft vessel traffic in confined riverine channels on shorelines and fish are of widespread concern. In the Pacific Northwest of the United States, wakes and subsequent beach run-up from ships transiting the Lower Columbia River have been observed to strand juvenile salmon and other fish. As part of a before-and-after study to assess stranding effects that may be associated with channel deepening, we measured 19 co-variables from observations of 126 vessel passages at three low-slope beaches and used multiple logistic regression to discern the significant factors influencing the frequency of stranding. Subyearling Chinook salmon were 82% of the fish stranded over all sites and seasons. Given a low-slope beach, stranding frequencies for juvenile salmon were significantly related to river location, salmon density in the shallows, a proxy for ship kinetic energy, tidal height, and two interactions. The beach types selected for our study do not include all the beach types along the Lower Columbia River so that the stranding probabilities described here cannot be extrapolated river-wide. A more sophisticated modeling effort, informed by additional field data, is needed to assess salmon losses by stranding for the entire lower river. Such modeling needs to include river-scale factors such as beach type, berms, proximity to navigation channel, and perhaps, proximity to tributaries that act as sources of out-migrating juvenile salmon. At both river and beach scales, no one factor produces stranding; rather interactions among several conditions produce a stranding event and give stranding its episodic nature.

  17. Colon cancer metastasis in mouse liver is not affected by hypercoagulability due to Factor V Leiden mutation

    PubMed Central

    Klerk, CPW; Smorenburg, SM; Spek, CA; Van Noorden, CJF

    2007-01-01

    Abstract Clinical trials have shown life-prolonging effects of antithrombotics in cancer patients, but the molecular mechanisms remain unknown due to the multitude of their effects. We investigated in a mouse model whether one of the targets of antithrombotic therapy, fibrin deposition, stimulates tumour development. Fibrin may provide either protection of cancer cells in the circulation against mechanical stress and the immune system, or form a matrix for tumours and/or angiogenesis in tumours to develop. Mice homozygous for Factor V Leiden (FVL), a mutation in one of the coagulation factors that facilitates fibrin formation, were used to investigate whether hypercoagulability affects tumour development in an experimental metastasis model. Liver metastases of colon cancer were induced in mice with the FVL mutation and wild-type littermates. At day 21, number and size of tumours at the liver surface, fibrin/fibrinogen distribution, vessel density and the presence of newly formed vessels in tumours were analysed. Number and size of tumours did not differ between mice with and without the FVL mutation. Fibrin/fibrinogen was found in the cytoplasm of hepatocytes and cancer cells, in blood vessels in liver and tumour tissue and diffusely distributed outside vessels in tumours, indicating leaky vessels. Vessel density and angiogenesis varied widely between tumours, but a pre-dominance for vessel-rich or vessel-poor tumours or vessel formation could not be found in either genotype. In conclusion, the FVL mutation has no effect on the development of secondary tumours of colon cancer in livers of mice. Fibrin deposition and thus inhibition of fibrin formation by anticoagulants do not seem to affect tumour development in this model. PMID:17635646

  18. Hydrological regulations, land use and a mud volcano affecting the sediment and carbon load of the tropical Brantas River, Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Jennerjahn, Tim; Jänen, Ingo

    2014-05-01

    Intensive human uses of the coastal zone and increasing extreme events are more and more endangering the integrity of coastal ecosystems during the Anthropocene. This is of particular importance in SE Asia where large parts of the population live in the coastal zone and economically depend on its resources. Intensive tectonic activity in the circum-Pacific 'Ring of fire' exposes the region to extreme natural events like volcano eruptions, earthquakes and occasionally following tsunamis. The Indonesian island of Java is a prime example in this respect because of its location on an active continental margin and a population density >1,000 inhabitants km-2. Its second largest river, the Brantas, empties into the shallow Madura Strait through two major branches, the Wonokromo and the Porong, the latter being responsible for 80 % of the discharge. Major land use in the catchment is agriculture (61 %) and the hydrology and sediment load of the river is regulated by 8 large dams and numerous weirs. The estuarine lowlands in the prograding delta were once covered by mangroves which were to a large extent replaced by aquaculture ponds. The eruption of a mud volcano near the Porong in 2006 added another factor affecting the amount and composition of the dissolved and particulate river loads. Concentrations of total suspended sediments (TSM) and particulate organic carbon (POC) displayed large seasonal variations in the Brantas before its diversion into the Porong and the Wonokromo as well as in the latter two with maxima during the wet season (Nov-April). High concentrations in the Porong during both seasons were mainly due to the constantly high input from the mud volcano. Favourable weathering conditions and agriculture as the predominant land use are responsible for high erosion rates of 4-14 mm yr-1 in the catchment. The 8 major dams and numerous weirs built between the 1970s and the 1990s retain a large amount of that sediment leading to an overall low sediment yield of

  19. Estimating changes in carbon burial on the western US coastal shelf due to anthropogenic influences on river exports

    NASA Astrophysics Data System (ADS)

    Sauer, M.; Bergamaschi, B. A.; Smith, R. A.; Zhu, Z.; Shih, J.

    2012-12-01

    Flux of nutrients and sediments to the coastal zone varies in response to land-use modification, reservoir construction, management action and population change. It is anticipated that future changes in the flux of these components in response to climate and terrestrial processes will affect carbon (C) burial in the coastal ocean. Coastal oceans store appreciable amounts of C as a result of river inflows: coastal primary production is enhanced by inputs of terrestrially derived nutrients, and C burial is controlled by terrestrial sediment supply. Assessing the capacity and changes to coastal C preservation, therefore, requires estimation of (1) riverine nutrient and sediment delivery to the coastal ocean, and (2) the enhanced C production and sediment deposition in the coastal ocean. The United States Geological Survey (USGS) has embarked on a congressionally-mandated nationwide effort to assess the future effects of climate and land use and land cover change (LULC) on C storage. The USGS has developed alternative scenarios for changes in US LULC from 2006 to 2100 based on the Intergovernmental Panel on Climate Change (IPCC) climate, economic, and demographic scenarios (Sohl et al 2012). These spatially-detailed scenarios provide inputs to national-scale SPARROW watershed models of total nitrogen, total phosphorus, total organic C (TOC), and suspended sediment (Smith et al 1997; Schwarz et al, 2006). The watershed models, in turn, provide inputs of nutrients, TOC, and sediment to a coupled model of coastal transport, production, and sedimentation. This coastal modelling component includes particulate C sedimentation and burial estimated as functions of bathymetry and pycnocline depth (Armstrong, et al 2002; Dunne et al 2007). River borne fluxes of TOC to US Pacific coastal waters under baseline conditions (1992) were 1.59 TgC/yr. Projected future (2050) fluxes under a regionally-downscaled LULC scenario aligned with the IPCC A2 scenario were similar (1.61TgC/yr). C

  20. Changes in the number and timing of days of ice-affected flow on northern New England rivers, 1930-2000

    USGS Publications Warehouse

    Hodgkins, G.A.; Dudley, R.W.; Huntington, T.G.

    2005-01-01

    Historical dates of ice-affected flows for 16 rural, unregulated rivers in northern New England, USA were analyzed. The total annual days of ice-affected flow decreased significantly (p < 0.1) over the 20th century at 12 of the 16 rivers. On average, for the nine longest-record rivers, the total annual days of ice-affected flow decreased by 20 days from 1936 to 2000, with most of the decrease occurring from the 1960s to 2000. Four of the 16 rivers had significantly later first dates of ice-affected flow in the fall. Twelve of the 16 rivers had significantly earlier last dates of ice-affected flow in the spring. On average, the last dates became earlier by 11 days from 1936 to 2000 with most of the change occurring from the 1960s to 2000. The total annual days of ice-affected flow were significantly correlated with November through April air temperatures (r = -0.70) and with November through April precipitation (r = -0.52). The last spring dates were significantly correlated with March through April air temperatures (r = -0.73) and with January through April precipitation (r = -0.37). March mean river flows increased significantly at 13 of the 16 rivers in this study. ?? Springer 2005.

  1. Patients affected by premature ejaculation due to glans hypersensitivity refuse circumcision as a potential definite treatment for their problem.

    PubMed

    Gallo, L

    2014-05-01

    The diagnosis of premature ejaculation (PE) was based on a score > 8 at the PEDT five-item questionnaire. Local anaesthetic treatment (LAT) was the first-line therapy. Subjects who obtained a normalisation of EPDT score (≤8) were considered responders to LAT and even affected by lifelong PE due glans hypersensitivity. We proposed to patients not completely satisfied with LAT to undergo circumcision as a potential definitive treatment for PE. All patients received exhaustive information about potential benefits, limitations and complications. In case of refusal, each man was asked for the reasons of his choice. A total of 152 patients were recruited. Hundred and twenty-four patients among 152 (81.6%) positively responded to LAT. Among the 124 LAT responders, 21 (17%) were completely satisfied. The remaining 103 men experienced adverse reactions. It was proposed to such patients if they would be interested to a definitive form of treatment to resolve their problem. All the patients responded positively to this question. Only four patients among them (3.9%) accepted. The remaining 99 (96.1%) refused providing the following reasons of their choice: absence of guarantees 82.8%; irreversibility of the procedure creating a permanent body alteration 75.7%; costs of the procedure 12.1%; fear of potential complications 7%.

  2. The thermal consequences of river-level variations in an urban groundwater body highly affected by groundwater heat pumps.

    PubMed

    García-Gil, Alejandro; Vázquez-Suñe, Enric; Schneider, Eduardo Garrido; Sánchez-Navarro, José Ángel; Mateo-Lázaro, Jesús

    2014-07-01

    The extensive implementation of ground source heat pumps in urban aquifers is an important issue related to groundwater quality and the future economic feasibility of existent geothermal installations. Although many cities are in the immediate vicinity of large rivers, little is known about the thermal river-groundwater interaction at a kilometric-scale. The aim of this work is to evaluate the thermal impact of river water recharges induced by flood events into an urban alluvial aquifer anthropogenically influenced by geothermal exploitations. The present thermal state of an urban aquifer at a regional scale, including 27 groundwater heat pump installations, has been evaluated. The thermal impacts of these installations in the aquifer together with the thermal impacts from "cold" winter floods have also been spatially and temporally evaluated to ensure better geothermal management of the aquifer. The results showed a variable direct thermal impact from 0 to 6 °C depending on the groundwater-surface water interaction along the river trajectory. The thermal plumes far away from the riverbed also present minor indirect thermal impacts due to hydraulic gradient variations.

  3. Factors Affecting the Survival of Upstream Migrant Adult Salmonids in the Columbia River Basin : Recovery Issues for Threatened and Endangered Snake River Salmon : Technical Report 9 of 11.

    SciTech Connect

    Dauble, Dennis D.; Mueller, Robert P.

    1993-06-01

    The Bonneville Power Administration (BPA) is developing conservation planning documentation to support the National Marine Fisheries Service`s (NMFS) recovery plan for Columbia Basin salmonid stocks that are currently listed under the Endangered Species Act (ESA). Information from the conservation planning documentation will be used as a partial scientific basis for identifying alternative conservation strategies and to make recommendations toward conserving, rebuilding, and ultimately removing these salmon stocks from the list of endangered species. This report describes the adult upstream survival study, a synthesis of biological analyses related to conditions affecting the survival of adult upstream migrant salmonids in the Columbia River system. The objective of the adult upstream survival study was to analyze existing data related to increasing the survival of adult migrant salmonids returning to the Snake River system. The fate and accountability of each stock during its upstream migration period and the uncertainties associated with measurements of escapement and survival were evaluated. Operational measures that affected the survival of adult salmon were evaluated including existing conditions, augmented flows from upstream storage release, and drawdown of mainstem reservoirs. The potential impacts and benefits of these measures to each ESA stock were, also described based on considerations of species behavior and run timing.

  4. Factors affecting temporal and spatial variations of Arsenic (III) and (V) in the geothermally impacted Jemez river, NM.

    NASA Astrophysics Data System (ADS)

    Hansson, L.

    2015-12-01

    Arsenic (As) in surface waters and groundwater is of global concern due to its potential negative impact on human health and eco systems. Due to the high leaching capacity of hot waters, geothermal waters in areas with As-rich bedrock, often contain high concentrations of As. This water can reach the surface through fractures and cracks that manifest through diffuse seeps and hot springs. The Soda Dam area in the Jemez Mountains of northwestern NM, with frequent hot springs and seeps, has long been of interest due to the hot spring's high discharge (1500L/s) of geothermal waters into the Jemez River. Although the species of As highly controls its mobility and toxicity, previous studies have focused exclusively on the total amounts of As in the waters, while little is known about the species occurring along the river. We collected water and "sediment" from 14 sites along the Jemez river to study factors governing spatial and temporal variations of As in hot springs and river water; the interrelationship between As(III) and As(V) and to calculate mass flows during the summer monsoon months of 2015. We found that As(V) is the dominant species along the river stretch of interest except for in the hot springs. As(III) occurs at all sites, and the fraction of total As(III) varies both on a spatial and temporal scale, ranging between 1-7 % upstream of Soda Dam, and 12 - 21 % below it. We also found that hot spring water in the beginning of the southwest monsoon season only contains As(III), but further into the season explicitly As(V), possibly due to a heavy rainfall occurring two days before sampling. The fraction of As(III) correlates well with alkalinity (R2 =0.98-0.59) and temperature (R2 = 0.86-0.46) although differently at different sampling occasions. Since As(III) is generally more toxic and mobile in water than As(V), our results emphasizes that risks associated with As may change over the season due to season-related changes in As speciation.

  5. The effect of controlled floods on decadal-scale changes in channel morphology and fine sediment storage in a debris-fan affected river canyon

    NASA Astrophysics Data System (ADS)

    Mueller, E. R.; Grams, P. E.; Schmidt, J. C.

    2013-12-01

    In 2011, a large magnitude flow release from Flaming Gorge Reservoir resulted in the third highest recorded discharge of the Green River downstream from Flaming Gorge Dam subsequent to its closure in 1963. Following this event, we made measurements of channel geometry, tracer gravel displacement, and sandbar sedimentology at four long-term monitoring reaches within the Canyon of Lodore in Dinosaur National Monument, Colorado. Here we integrate these data with nearly two decades of channel monitoring at these sites, encompassing five controlled floods, and providing a coarse resolution, but coherent, picture of channel response and changes in fine sediment storage in a canyon-bound river. We discuss these results in the context of long-term monitoring of controlled flood response along the Colorado River in Marble and Grand Canyons, Arizona. In Canyon of Lodore, moderate, short-duration controlled floods have had little effect on channel morphology or fine sediment storage. Alternatively, higher magnitude floods approaching the pre-dam mean annual flood, such as in 1999 and 2011, tended to be long duration and scoured fine sediment from the channel bed, in some places up to 5 m, while building eddy sandbars to within a meter of flood stage. This resulted in a net export of sediment from the monitored reaches. Between floods, eddy sand bars erode and the pools fill with fine sediment. We have observed only minor erosion or reworking of gravel bars and channel margin deposits stabilized by vegetation encroachment. The Green River in Canyon of Lodore is a scaled-down version of the Colorado River in debris fan-affected Marble and Grand Canyons. Both rivers now exist in varying degrees of sediment deficit due to upstream reservoirs. Coarse sediment from debris fans and hillslopes limits vertical incision and channel migration, focusing the post-dam geomorphic response to sediment imbalance on fine sediment located in eddy sandbars, pools, and channel margin deposits. In

  6. Biophysical processes affecting DOM dynamics at the Arno river mouth (Tyrrhenian Sea).

    PubMed

    Retelletti Brogi, S; Gonnelli, M; Vestri, S; Santinelli, C

    2015-02-01

    Dissolved organic carbon (DOC) and optical properties (absorption and fluorescence) of chromophoric dissolved organic matter (CDOM) were measured in October 2012, at the Arno river mouth and in a coastal station close to it. The data reported indicates that the Arno river represents an important source of DOC and CDOM to this coastal area, with a total DOC flux of 11.23-12.04 · 10(9)g C · y(-1). Moving from the river to the sea, CDOM absorption and fluorescence decreased, while the spectral slope increased, suggesting a change in the molecular properties of CDOM. Mineralization experiments were carried out in order to investigate the main processes of DOM removal and/or transformation in riverine and coastal water. DOC removal rates were 20 μM · month(-1) in the river and 3 μM · month(-1) in the seawater, while CDOM was released during the first 30 days and removed in the following 40 days. PMID:25463937

  7. Geomorphic change along a gravel bed river affected by volcanic eruption: Rio Blanco - Volcan Chaiten (South Chile)

    NASA Astrophysics Data System (ADS)

    Picco, Lorenzo; Ravazzolo, Diego; Ulloa, Hector; Iroumé, Andres; Aristide Lenzi, Mario

    2014-05-01

    Gravel bed rivers are environments shaped by the balance of flow, sediment regimes, large wood (LW) and vegetation. Geomorphic changes are response to fluctuations and changes of runoff and sediment supply involving mutual interactions among these factors. Typically, many natural disasters (i.e. debris flows, floods and forest fires) can affect the river basin dynamics. Explosive volcanic eruptions present, instead, the potential of exerting severe impacts as, for example, filling river valleys or changing river network patterns thanks to massive deposition of tephra and volcanic sediment all over the main channel and over the basin. These consistent impacts can strongly affect both hydrology and sediment transport dynamics, all over the river system, producing huge geomorphic changes. During the last years there has been a consistent increase in the survey technologies that permit to monitor geomorphic changes and to estimate sediment budgets through repeat topographic surveys. The calculation of differences between subsequent DEMs (difference of DEMs, DoD) is a commonly applied method to analyze and quantify these dynamics. Typically the higher uncertainty values are registered in areas with higher topographic variability and lower point density. This research was conducted along a ~ 2.2 km-long sub-reach of the Blanco River (Southern Chile), a fourth-order stream that presents a mainly rainfall regime with winter peak flows. The May 2008 Chaitén volcanic eruption strongly affected the entire Rio Blanco basin. The entire valley was highly exposed to the pyroclastic and fluvial flows, which affected directly a consistent area of evergreen forests. Extreme runoff from the upper Blanco catchment aggraded the channel and deposited up to several meters of tephra, alluvium, and LW along the entire river system. Aims of this contribution are to define and quantify the short term evolution of the Blanco River after the big eruption event and a subsequent consistent

  8. Evaluation of Metal Toxicity in Streams Affected by Abandoned Mine Lands, Upper Animas River Watershed, Colorado

    USGS Publications Warehouse

    Besser, John M.; Allert, Ann L.; Hardesty, Douglas K.; Ingersoll, Christopher G.; May, Thomas W.; Wang, Ning; Leib, Kenneth J.

    2001-01-01

    Acid drainage from abandoned mines and from naturally-acidic rocks and soil in the upper Animas River watershed of Colorado generates elevated concentrations of acidity and dissolved metals in stream waters and deposition of metal-contaminated particulates in streambed sediments, resulting in both toxicity and habitat degradation for stream biota. High concentrations of iron (Fe), aluminum (Al), zinc (Zn), copper (Cu), cadmium (Cd), and lead (Pb) occur in acid streams draining headwaters of the upper Animas River watershed, and high concentrations of some metals, especially Zn, persist in circumneutral reaches of the Animas River and Mineral Creek, downstream of mixing zones of acid tributaries. Seasonal variation of metal concentrations is reflected in variation in toxicity of stream water. Loadings of dissolved metals to the upper Animas River and tributaries are greatest during summer, during periods of high stream discharge from snowmelt and monsoonal rains, but adverse effects on stream biota may be greater during winter low-flow periods, when stream flows are dominated by inputs of groundwater and contain greatest concentrations of dissolved metals. Fine stream-bed sediments of the upper Animas River watershed also contain elevated concentrations of potentially toxic metals. Greatest sediment metal concentrations occur in the Animas River upstream from Silverton, where there are extensive deposits of mine and mill tailings, and in mixing zones in the Animas River and lower Mineral Creek, where precipitates of Fe and Al oxides also contain high concentrations of other metals. This report summarizes the findings of a series of toxicity studies in streams of the upper Animas River watershed, conducted on-site and in the laboratory between 1998 and 2000. The objectives of these studies were: (1) to determine the relative toxicity of stream water and fine stream-bed sediments to fish and invertebrates; (2) to determine the seasonal range of toxicity in stream

  9. Factors affecting route selection and survival of steelhead kelts at Snake River dams in 2012 and 2013

    SciTech Connect

    Harnish, Ryan A.; Colotelo, Alison H. A.; Li, Xinya; Fu, Tao; Ham, Kenneth D.; Deng, Zhiqun; Green, Ethan D.

    2015-03-31

    In 2012 and 2013, Pacific Northwest National Laboratory (PNNL) conducted a study that summarized the passage route proportions and route-specific survival rates of steelhead kelts that passed through Federal Columbia River Power System (FCRPS) dams. To accomplish this, a total of 811 steelhead kelts were tagged with Juvenile Salmon Acoustic Telemetry System (JSATS) transmitters. Acoustic receivers, both autonomous and cabled, were deployed throughout the FCRPS to monitor the downstream movements of tagged kelts. Kelts were also tagged with passive integrated transponder tags to monitor passage through juvenile bypass systems (JBS) and detect returning fish. The current study evaluated data collected in 2012 and 2013 to identify environmental, temporal, operational, individual, and behavioral variables that were related to forebay residence time, route of passage, and survival of steelhead kelts at FCRPS dams on the Snake River. Multiple approaches, including 3-D tracking, bivariate and multivariable regression modeling, and decision tree analyses were used to identify the environmental, temporal, operational, individual, and behavioral variables that had the greatest effect on forebay residence time, route of passage, and route-specific and overall dam passage survival probabilities for tagged kelts at Lower Granite (LGR), Little Goose (LGS), and Lower Monumental (LMN) dams. In general, kelt behavior and discharge appeared to work independently to affect forebay residence times. Kelt behavior, primarily approach location, migration depth, and “searching” activities in the forebay, was found to have the greatest influence on their route of passage. The condition of kelts was the single most important factor affecting their survival. The information gathered in this study may be used by dam operators and fisheries managers to identify potential management actions to improve in-river survival of kelts or collection methods for kelt reconditioning programs to aid

  10. Mercury pollution on district of Dimembe river system North Sulawesi, Indonesia, due to traditional gold mining activities

    NASA Astrophysics Data System (ADS)

    Ayhuan, D.; Atteng, O.; Dondokambey, A.; Randuk, M.

    2003-05-01

    Mercury contamination caused by the amalgamation of gold in small scale gold mining is a environmental problem. Small-scale gold mining (SSGM) is common in mineral endowed developing countries. It offers an important means of livehood and has served as a safety net in times of natural calamities or economic distress. In north Sulawesi Province alone, approximately 22,000 small-scale gold miners were active in 1998, and produced an estimated 10 tonnes of gold bullion. Activities of traditional / illegal gold mining (PETI) in Dimembe of district, which is located in Minahasa Regency, North Sulawesi Province. The major environmental concern associated with PETI in mercury pollution from processing of gold-bearing ore. In both the inorganic and organic forms, mercury is one of the most toxic substances to humans. One of the environmental pollution is water pollution on district of Dimembe river system that is probably caused by the use of mercury (Hg) in processing mine ore. This mercury is used in an iron rolling vessel, wllich is called tromol. Mercury concentration at employed in this operation reaches 1 kg out of 30 kg ore. Sampling stage was conducted at Warat river, downstream Taiawaan river, Merut river and Kadumut river on late April 2002 by BAPEDALDA team together with Health Laboratory staff. Material which were sampled was water. Sampling methods carried out were bottle sample immersed about 10 cm below the water surface. The analysis method used was mercury analyzer. The analysis result show that total concentration of mercury range from 1. 69 to 25. 54 ppb. This concentration is closed to Water Quality Standard IV Class that is 0.005 mg/L (Regulation Government No. 82/2001). The result of this research indicate that the district of Dimembe river system in the gold mining area have been contaminated by mercury.

  11. Reconnaissance Study of Water Quality in the Mining-Affected Aries River Basin, Romania

    USGS Publications Warehouse

    Friedel, Michael J.; Tindall, James A.; Sardan, Daniel; Fey, David L.; Poputa, G.L.

    2008-01-01

    The Aries River basin of western Romania has been subject to mining activities as far back as Roman times. Present mining activities are associated with the extraction and processing of various metals including Au, Cu, Pb, and Zn. To understand the effects of these mining activities on the environment, this study focused on three objectives: (1) establish a baseline set of physical parameters, and water- and sediment-associated concentrations of metals in river-valley floors and floodplains; (2) establish a baseline set of physical and chemical measurements of pore water and sediment in tailings; and (3) provide training in sediment and water sampling to personnel in the National Agency for Mineral Resources and the Rosia Poieni Mine. This report summarizes basin findings of physical parameters and chemistry (sediment and water), and ancillary data collected during the low-flow synoptic sampling of May 2006.

  12. Trace metal distribution in pristine permafrost-affected soils of the Lena River Delta and its Hinterland, Northern Siberia, Russia

    NASA Astrophysics Data System (ADS)

    Antcibor, I.; Zubrzycki, S.; Eschenbach, A.; Kutzbach, L.; Bol'shiyanov, D.; Pfeiffer, E.-M.

    2013-02-01

    Soils are an important compartment of ecosystems and have the ability to immobilize chemicals preventing their movement to other environment compartments. Predicted climatic changes together with other anthropogenic influences on Arctic terrestrial environments may affect biogeochemical processes enhancing leaching and migration of trace elements in permafrost-affected soils. This is especially important since the Arctic ecosystems are considered to be very sensitive to climatic changes as well as to chemical contamination. This study characterizes background levels of trace metals in permafrost-affected soils of the Lena River Delta and its hinterland in northern Siberia (73.5° N-69.5° N) representing a remote region far from evident anthropogenic trace metal sources. Investigations on total element contents of iron (Fe), arsenic (As), manganese (Mn), zinc (Zn), nickel (Ni), copper (Cu), lead (Pb), cadmium (Cd), cobalt (Co) and mercury (Hg) in different soil types developed in different geological parent materials have been carried out. The highest concentrations of the majority of the measured elements were observed in soils belonging to ice-rich permafrost sediments formed during the Pleistocene (ice-complex) in the Lena River Delta region. Correlation analyses of trace metal concentrations and soil chemical and physical properties at a Holocene estuarine terrace and two modern floodplain levels in the southern-central Lena River Delta (Samoylov Island) showed that the main factors controlling the trace metal distribution in these soils are organic matter content, soil texture and contents of iron and manganese-oxides. Principal Component Analysis (PCA) revealed that soil oxides play a significant role in trace metal distribution in both top and bottom horizons. Occurrence of organic matter contributes to Cd binding in top soils and Cu binding in bottom horizons. Observed ranges of the background concentrations of the majority of trace elements were similar to

  13. Time changes in suspended sediment radiocesium concentration in rivers in Fukushima affected by the Fukushima Daiichi NPP accident

    NASA Astrophysics Data System (ADS)

    Onda, Y.

    2015-12-01

    Due to Fukushima Daiichi Nuclear Power Plant accident, radioactive materials including Cs-134 and Cs-137 were widely distributed in surrounded area. The radiocesium deposited in Fukushima area have been transported in river networks. The monitoring started at 6 sites from June 2011. Subsequently, additional 24 monitoring sites were installed between October 2012 and January 2013. Flow and turbidity (for calculation of suspended sediment concentration) were measured at each site, while suspended sediments and river water were collected every one or half month to measure Cs-134 and Cs-137 activity concentrations by gamma spectrometry. Our monitoring result data demonstrated that the Cs-137 activity concentration in sediment eroded from the runoff-erosion plot, has been almost constant for the past 3 years, however the Cs-137 concentration of suspended sediment from the forested catchment showed a slight decrease through with time. On the other hand, the suspended sediment from paddy fields and those in river water from large catchments exhibited rapid decrease in Cs-137 activity concentration with time. The decreasing trend of Cs-137 activity concentration was fitted using a two-component exponential model. Differences in the exponential reduction rates of the model were compared and discussed with respect to various land uses and catchment scales. Such analysis can provide important insights into the future prediction of radiocesium wash-off from catchments with different land uses.

  14. Measurement error affects risk estimates for recruitment to the Hudson River stock of striped bass.

    PubMed

    Dunning, Dennis J; Ross, Quentin E; Munch, Stephan B; Ginzburg, Lev R

    2002-06-01

    We examined the consequences of ignoring the distinction between measurement error and natural variability in an assessment of risk to the Hudson River stock of striped bass posed by entrainment at the Bowline Point, Indian Point, and Roseton power plants. Risk was defined as the probability that recruitment of age-1+ striped bass would decline by 80% or more, relative to the equilibrium value, at least once during the time periods examined (1, 5, 10, and 15 years). Measurement error, estimated using two abundance indices from independent beach seine surveys conducted on the Hudson River, accounted for 50% of the variability in one index and 56% of the variability in the other. If a measurement error of 50% was ignored and all of the variability in abundance was attributed to natural causes, the risk that recruitment of age-1+ striped bass would decline by 80% or more after 15 years was 0.308 at the current level of entrainment mortality (11%). However, the risk decreased almost tenfold (0.032) if a measurement error of 50% was considered. The change in risk attributable to decreasing the entrainment mortality rate from 11 to 0% was very small (0.009) and similar in magnitude to the change in risk associated with an action proposed in Amendment #5 to the Interstate Fishery Management Plan for Atlantic striped bass (0.006)--an increase in the instantaneous fishing mortality rate from 0.33 to 0.4. The proposed increase in fishing mortality was not considered an adverse environmental impact, which suggests that potentially costly efforts to reduce entrainment mortality on the Hudson River stock of striped bass are not warranted.

  15. Trace metal distribution in pristine permafrost-affected soils of the Lena River delta and its hinterland, northern Siberia, Russia

    NASA Astrophysics Data System (ADS)

    Antcibor, I.; Eschenbach, A.; Zubrzycki, S.; Kutzbach, L.; Bolshiyanov, D.; Pfeiffer, E.-M.

    2014-01-01

    Soils are an important compartment of ecosystems and have the ability to buffer and immobilize substances of natural and anthropogenic origin to prevent their movement to other environment compartments. Predicted climatic changes together with other anthropogenic influences on Arctic terrestrial environments may affect biogeochemical processes enhancing leaching and migration of trace elements in permafrost-affected soils. This is especially important since Arctic ecosystems are considered to be highly sensitive to climatic changes as well as to chemical contamination. This study characterises background levels of trace metals in permafrost-affected soils of the Lena River delta and its hinterland in northern Siberia (73.5-69.5° N), representing a remote region far from evident anthropogenic trace metal sources. Investigations on the element content of iron (Fe), arsenic (As), manganese (Mn), zinc (Zn), nickel (Ni), copper (Cu), lead (Pb), cadmium (Cd), cobalt (Co), and mercury (Hg) in different soil types developed in different geological parent materials have been carried out. The highest median concentrations of Fe and Mn were observed in soils belonging to ice-rich permafrost sediments formed during the Pleistocene (ice-complex) while the highest median values of Ni, Pb and Zn were found in soils of both the ice-complex and the Holocene estuarine terrace of the Lena River delta region, as well as in the southernmost study unit of the hinterland area. Detailed observations of trace metal distribution on the micro scale showed that organic matter content, soil texture and iron-oxide contents influenced by cryogenic processes, temperature, and hydrological regimes are the most important factors determining the metal abundance in permafrost-affected soils. The observed range of trace element background concentrations was similar to trace metal levels reported for other pristine northern areas.

  16. Drawdown changes affected by flow rate and location of pumping wells near a river

    NASA Astrophysics Data System (ADS)

    Chen, S. N.; Shu, L. C.

    2016-08-01

    Riverside groundwater exploitation is one of the main means of utilizing groundwater resources. This paper describes the impact of drawdown conditions with changes in the river flow and pumping well locations, and analyzes the interaction between the groundwater and surface water. Based on long-term hydrological gauging data, abundant hydrogeological test data, and the numerical simulation results for a typical well field of the Qinbei Power Plant, this paper presents three different cases of pumping well locations and four different cases of river flow rates. Finally, the abovementioned cases are integrated into 12 extraction groups and the drawdown conditions are calculated for each group. The results show that, for a given set of flow rate conditions, a location set in a recharge zone exhibited the maximum drawdown, while a location in a transition zone had the second-largest drawdown, and a location in a discharge zone had the minimum drawdown. In addition, assuming the same locations for the pumping wells, the drawdown change from small to large corresponded to 100%, 75%, 50%, and 25% of the original flow. This paper provides a foundation for future study of the calculation of riverside groundwater exploration with changes in the flow rate and well locations.

  17. Dramatic beach and nearshore morphological changes due to extreme flooding at a wave-dominated river mouth

    USGS Publications Warehouse

    Barnard, P.L.; Warrick, J.A.

    2010-01-01

    Record flooding on the Santa Clara River of California (USA) during January 2005 injected ∼ 5 million m3 of littoral-grade sediment into the Santa Barbara Littoral Cell, approximately an order of magnitude more than both the average annual river loads and the average annual alongshore littoral transport in this portion of the cell. This event appears to be the largest sediment transport event on record for a Southern California river. Over 170 m of local shoreline (mean high water (MHW)) progradation was observed as a result of the flood, followed by 3 years of rapid local shoreline recession. During this post-flood stage, linear regression-determined shoreline change rates are up to −45 m a− 1 on the subaerial beach (MHW) and − 114 m a− 1 on the submarine delta (6 m isobath). Starting approximately 1 km downdrift of the river mouth, shoreline progradation persisted throughout the 3-year post-flood monitoring period, with rates up to + 19 m a− 1. Post-flood bathymetric surveys show nearshore (0 to 12 m depth) erosion on the delta exceeding 400 m3/m a− 1, more than an order of magnitude higher than mean seasonal cross-shore sediment transport rates in the region. Changes were not constant with depth, however; sediment accumulation and subsequent erosion on the delta were greatest at − 5 to − 8 m, and accretion in downdrift areas was greatest above –2 m. Thus, this research shows that the topographic bulge (or “wave”) of sediment exhibited both advective and diffusive changes with time, although there were significant variations in the rates of change with depth. The advection and diffusion of the shoreline position was adequately reproduced with a simple “one line” model, although these modeling techniques miss the important cross-shore variations observed in this area. This study illustrates the importance of understanding low-frequency, high volume coastal discharge events for understanding short- and long-term sediment supply, littoral

  18. A geomorphic framework to assess changes to aquatic habitat due to flow regulation and channel and floodplain alteration of the Cedar River, Washington

    NASA Astrophysics Data System (ADS)

    Gendaszek, A. S.; Magirl, C. S.; Barnas, C. R.; Konrad, C. P.; Little, R.

    2010-12-01

    Flow regulation, bank armoring, and floodplain alteration since the early 20th century have contributed to significant changes in the hydrologic regime and geomorphic processes of the Cedar River in Washington State. The Cedar River originates in the Cascade Range, provides drinking water to the Seattle metropolitan area, and supports several populations of anadromous salmonids. Flow regulation currently has limited influence on the magnitude, duration, and timing of high-flow events, which affect the incubation of salmonids as well as the production and maintenance of their habitat. Unlike structural changes to the channel and floodplain, flow regulation may be modified in the short-term to improve the viability of salmon populations. An understanding of the effects of flow regulation on those populations must be discerned over a range of scales from individual floods that affect the size of individual year classes to decadal high flow regime that influences the amount and quality of channel and off-channel habitat available for spawning and rearing. We present estimates of reach-scale sediment budgets and changes to channel morphology derived from historical orthoimagery, specific gage analyses at four long-term streamflow-gaging stations to quantify trends in aggradation, and hydrologic statistics of the magnitude and duration of peak streamflows. These data suggest a gradient of channel types from unconfined, sediment-rich segments to confined, sediment-poor segments that are likely to have distinct responses to high flows. Particle-size distribution data and longitudinal water surface and streambed profiles for the 56 km downstream of Chester Morse Lake measured in 2010 show the spatial extent of preferred salmonid habitat along the Cedar River. These historical and current data constitute a geomorphic framework to help assess different river management scenarios for salmonid habitat and population viability.

  19. The fate of arsenic in sediments formed at a river confluence affected by acid mine drainage

    NASA Astrophysics Data System (ADS)

    Guerra, P. A.; Pasten, P. A.; Pizarro, G.; Simonson, K.; Escauriaza, C. R.; Gonzalez, C.; Bonilla, C.

    2012-12-01

    Fluvial confluences receiving acid mine drainage may play a critical role in a watershed as a suite of interactions between chemistry and hydrodynamics occur, determining the fate of toxic contaminants like arsenic. Solid reactive phases of iron and/or aluminum oxi-hydroxides may form or transform, ranging from iron oxide nanoparticles that aggregate and form floccules that are transported in the suspended load up to gravel and arsenic-rich rock coatings. In order to further understand the role of reactive fluvial confluences, we have studied the mixing between the Caracarani River (flow=170-640 L/s, pH 8, conductivity 1.5 mS/cm, total As<0.1 mg/L and total Fe< 5 mg/L) and the Azufre River (flow=45-245 L/s, pH<2, conductivity > 10 mS/cm, total As>2 mg/L, total Fe=35-125 mg/L), located in the Lluta watershed in northern Chile. This site is an excellent natural laboratory located in a water-scarce area, where the future construction of a dam has prompted the attention of decision makers and scientists interested in weighing the risks derived by the accumulation of arsenic-rich sediments. Suspended sediments (> 0.45 μm), riverbed sediments, and coated rocks were collected upstream and downstream from the confluence. Suspended sediments >0.45 μm and riverbed sediments were analyzed by total reflection x-ray fluorescence for metals, while coated river bed rocks were analyzed by chemical extractions and a semi-quantitative approach through portable x-ray fluorescence. Water from the Caracarani and Azufre rivers were mixed in the laboratory at different ratios and mixing velocities aiming to characterize the effect of the chemical-hydrodynamic environment where arsenic solids were formed at different locations in the confluence. Despite a wide range of iron and arsenic concentrations in the suspended sediments from the field (As=1037 ± 1372 mg/kg, Fe=21.0 ± 24.5 g/kg), we found a rather narrow As/Fe ratio, increasing from 36.5 to 55.2 mgAs/kgFe when the bulk water p

  20. How run-of-river operation affects hydropower generation and value.

    PubMed

    Jager, Henriette I; Bevelhimer, Mark S

    2007-12-01

    Regulated rivers in the United States are required to support human water uses while preserving aquatic ecosystems. However, the effectiveness of hydropower license requirements nationwide has not been demonstrated. One requirement that has become more common is "run-of-river" (ROR) operation, which restores a natural flow regime. It is widely believed that ROR requirements (1) are mandated to protect aquatic biota, (2) decrease hydropower generation per unit flow, and (3) decrease energy revenue. We tested these three assumptions by reviewing hydropower projects with license-mandated changes from peaking to ROR operation. We found that ROR operation was often prescribed in states with strong water-quality certification requirements and migratory fish species. Although benefits to aquatic resources were frequently cited, changes were often motivated by other considerations. After controlling for climate, the overall change in annual generation efficiency across projects because of the change in operation was not significant. However, significant decreases were detected at one quarter of individual hydropower projects. As expected, we observed a decrease in flow during peak demand at 7 of 10 projects. At the remaining projects, diurnal fluctuations actually increased because of operation of upstream storage projects. The economic implications of these results, including both producer costs and ecologic benefits, are discussed. We conclude that regional-scale studies of hydropower regulation, such as this one, are long overdue. Public dissemination of flow data, license provisions, and monitoring data by way of on-line access would facilitate regional policy analysis while increasing regulatory transparency and providing feedback to decision makers.

  1. Patterns in atmospheric circulation affect emission sources contributing to nitrogen deposition in the Columbia River Gorge, Pacific Northwest USA

    NASA Astrophysics Data System (ADS)

    Anderson, S. M.; Chung, S. H.; Welker, J. M.; Harlow, B.; Evans, R. D.

    2014-12-01

    The Columbia River Gorge separating Oregon and Washington provides an ideal setting to investigate how atmospheric circulation patterns determine types of emission sources contributing to atmospheric deposition. Up-gorge and down-gorge atmospheric circulation patterns each provide a different suite of emission sources. Up-gorge airflow originates in the Portland-Vancouver metro area dominated by urban and industrial sources. Down-gorge patterns originate in the Columbia River basin, which is dominated by agricultural production. We tested the dependence of emission sources contributing to atmospheric deposition on circulation patterns by measuring the isotopic composition of nitrate (NO3-) in 2003-2004 precipitation samples from the WA98-Columbia River Gorge NADP & USNIP site. Circulation patterns were determined using back-trajectory analysis with the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model using the archived EDAS meteorological dataset. We observed a significant difference (P=0.01) between up-gorge and down-gorge patterns with mean δ15N-NO3- of +1.8 and -2.1‰ for up- and down-gorge, respectively. The differences observed between these two patterns is likely tied to the different emission sources of N found in these different geographic areas. The lower δ15N of down-gorge sources is due to the large amount of agricultural production in the Columbia River basin. Observed values for the up-gorge patterns likely result from industrial and fossil fuel emissions of NOx, the precursor of deposited NO3-, in the Portland-Vancouver area. The significantly greater amount of NO3- in precipitation from up-gorge patterns (0.72 mg/L) compared to down-gorge patterns (0.36 mg/L, P=0.01) supports the influence of urban sources rather than relatively clean marine air which characteristically has low amounts of NO3-. No significant differences are found in δ18Onitrate or Δ17Onitrate between the two patterns, suggesting that atmospheric chemistry

  2. Temporal dynamics of groundwater-dissolved inorganic carbon beneath a drought-affected braided stream: Platte River case study

    NASA Astrophysics Data System (ADS)

    Boerner, Audrey R.; Gates, John B.

    2015-05-01

    Impacts of environmental changes on groundwater carbon cycling are poorly understood despite their potentially high relevance to terrestrial carbon budgets. This study focuses on streambed groundwater chemistry during a period of drought-induced river drying and consequent disconnection between surface water and groundwater. Shallow groundwater underlying vegetated and bare portions of a braided streambed in the Platte River (Nebraska, USA) was monitored during drought conditions in summer 2012. Water temperature and dissolved inorganic carbon (dominated by HCO3-) in streambed groundwater were correlated over a 3 month period coinciding with a decline in river discharge from 35 to 0 m3 s-1. Physical, chemical, and isotopic parameters were monitored to investigate mechanisms affecting the HCO3- trend. Equilibrium thermodynamic modeling suggests that an increase of pCO2 near the water table, coupled with carbonate mineral weathering, can explain the trend. Stronger temporal trends in Ca2+ and Mg2+ compared to Cl- are consistent with carbonate mineral reequilibria rather than evaporative concentration as the primary mechanism of the increased HCO3-. Stable isotope trends are not apparent, providing further evidence of thermodynamic controls rather than evaporation from the water table. A combination of increased temperature and O2 in the dewatered portion of the streambed is the most likely driver of increased pCO2 near the water table. Results of this study highlight potential linkages between surface environmental changes and groundwater chemistry and underscore the need for high-resolution chemical monitoring of alluvial groundwater in order to identify environmental change impacts.

  3. Factors affecting post-control reinvasion by seed of an invasive species, Phragmites australis, in the central Platte River, Nebraska.

    USGS Publications Warehouse

    Galatowitsch, Susan M.; Larson, Diane L.; Larson, Jennifer L.

    2016-01-01

    Invasive plants, such as Phragmites australis, can profoundly affect channel environments of large rivers by stabilizing sediments and altering water flows. Invasive plant removal is considered necessary where restoration of dynamic channels is needed to provide critical habitat for species of conservation concern. However, these programs are widely reported to be inefficient. Post-control reinvasion is frequent, suggesting increased attention is needed to prevent seed regeneration. To develop more effective responses to this invader in the Central Platte River (Nebraska, USA), we investigated several aspects of Phragmites seed ecology potentially linked to post-control reinvasion, in comparison to other common species: extent of viable seed production, importance of water transport, and regeneration responses to hydrology. We observed that although Phragmites seed does not mature until very late in the ice-free season, populations produce significant amounts of viable seed (>50 % of filled seed). Most seed transported via water in the Platte River are invasive perennial species, although Phragmites abundances are much lower than species such as Lythrum salicaria, Cyperus esculentus and Phalaris arundinacea. Seed regeneration of Phragmites varies greatly depending on hydrology, especially timing of water level changes. Flood events coinciding with the beginning of seedling emergence reduced establishment by as much as 59 % compared to flood events that occurred a few weeks later. Results of these investigations suggest that prevention of seed set (i.e., by removal of flowering culms) should be a priority in vegetation stands not being treated annually. After seeds are in the seedbank, preventing reinvasion using prescribed flooding has a low chance of success given that Phragmites can regenerate in a wide variety of hydrologic microsites.

  4. Factors Affecting the Occurrence and Distribution of Pesticides in the Yakima River Basin, Washington, 2000

    USGS Publications Warehouse

    Johnson, Henry M.

    2007-01-01

    The Yakima River Basin is a major center of agricultural production. With a cultivated area of about 450,000 ha (hectares), the region is an important producer of tree fruit, grapes, hops, and dairy products as well as a variety of smaller production crops. To control pest insects, weeds, and fungal infections, about 146 pesticide active ingredients were applied in various formulations during the 2000 growing season. Forty-six streams or drains in the Yakima River Basin were sampled for pesticides in July and October of 2000. Water samples also were collected from 11 irrigation canals in July. The samples were analyzed for 75 of the pesticide active ingredients applied during the 2000 growing season - 63 percent of the pesticides were detected. An additional 14 pesticide degradates were detected, including widespread occurrence of 2 degradates of DDT. The most frequently detected herbicide was 2,4-D, which was used on a variety of crops and along rights-of-way. It was detected in 82 percent of the samples collected in July. The most frequently detected insecticide was azinphos-methyl, which was used primarily on tree fruit. It was detected in 37 percent of the samples collected in July. All occurrences of azinphos-methyl exceeded the Environmental Protection Agency recommended chronic concentration for the protection of aquatic organisms. More than 90 percent of the July samples and 79 percent of the October samples contained two or more pesticides, with a median of nine in July and five in October. The most frequently occurring herbicides in mixtures were atrazine, 2,4-D, and the degradate deethylatrazine. The most frequently occurring insecticides in mixtures were azinphos-methyl, carbaryl, and p,p'-DDE (a degradate of DDT). A greater number of pesticides and higher concentrations were found in July than in October, reflecting greater usage and water availability for transport during the summer growing and irrigation season. Most of the samples collected in

  5. Selected characteristics of stormflow and base flow affected by land use and cover in the Chickahominy River basin, Virginia, 1989-91

    USGS Publications Warehouse

    Focazio, M.J.; Cooper, R.E.

    1995-01-01

    The Chickahominy River is the principal source of raw-water supply managed by the Department of Public Utilities, City of Newport News. Selected characteristics of stormflow and base flow, and major land use and cover factors that affect the distribution, movement, and quality of water of the nontidal Chickahominy River were monitored at three continuous-record stations and two partial-record stations. The stations are located in areas that drain urban, residential, and rural land uses.

  6. Computer Simulation of Stress-Strain State of Pipeline Section Affected by Abrasion Due to Mechanical Impurities

    NASA Astrophysics Data System (ADS)

    Burkov, P. V.; Afanas’ev, R. G.; Burkova, S. P.

    2016-04-01

    The paper presents the effect of abrasive wear of the pipeline section occurred due to mechanical impurities in the transported gas flow. The approaches to the detection of the maximum specific wear of the pipeline wall and the geometry of abrasion are the main problems of computer simulation described in this paper.

  7. Satellite and ground detection of very dense smoke clouds produced on the islands of the Paraná river delta that affected a large region in Central Argentina

    NASA Astrophysics Data System (ADS)

    Ipiña, A.; Salum, G. M.; Crinó, E.; Piacentini, R. D.

    2012-03-01

    Intense fires were produced on the Paraná river delta islands, Argentina, during most part of 2008, by a combination of an exceptionally dry period and the farmers' use of a fire land-cleaning technique. In April 2008, those fires significantly affected the nearby regions and their inhabitants, from Rosario city to Buenos Aires mega-city. In this work we present satellite as well as ground Aerosol Optical Depth (AOD) at 550 nm data obtained during the propagation of pollution clouds to the central zone of Argentina. The highest value (1.18) was registered at Buenos Aires by atmospheric remote sensing, using the satellite instrument MODIS/Terra on April 18th 2008 at 10:35 local time (= UT - 3 h). On the same day, ground air quality detectors also measured in this city the highest Total Suspended Particle (TSP) value of the month, 2.02 mg/m3. The AOD(550) daily variation at Rosario Astronomical Observatory, which is located near the Paraná riverside, was derived by combining solar ultraviolet erythemal irradiance data (measured with a YES biometre) with model calculations. On April 25th 2008, from 12:00 to 15:30 local time, a rather high and constant AOD(550) value was registered, with a mean value of (0.90 ± 0.21). Cities located on the side of the Rosario-Buenos Aires highway (San Nicolás, Baradero and San Pedro) were also affected, showing a mean AOD(550) between the Rosario and Buenos Aires values. The particulate matter was collected with gridded samplers placed on the Paraná river islands as well as at the Rosario Observatory. They were analysed with a Scanning Electron Microscope (SEM) and mainly showed a biological origin. Even if normally large particles travel small distances from the source, organic aerosol in the range of 40-100 μm and complex asymmetric structures were registered several kilometres away from the aerosol sources on the islands. Another event of intense UV index attenuation (98.6%) occurred on September 18th 2008, due to very dense

  8. Assessment of water quality and factors affecting dissolved oxygen in the Sangamon River, Decatur to Riverton, Illinois, summer 1982

    USGS Publications Warehouse

    Schmidt, A.R.; Stamer, J.K.

    1987-01-01

    Water quality and processes that affect the dissolved-oxygen concentration in a 45.9 mile reach of the Sangamon River from Decatur to Riverton, Illinois, were determined from data collected during low-flow periods in the summer of 1982. Relations among dissolved oxygen, water discharge, biochemical oxygen demand, ammonia and nitrite plus nitrate concentrations, and photosynthetic-oxygen production were simulated using a one-dimensional, steady-state computer model. Average dissolved oxygen concentrations ranged from 8.0 milligrams per liter at the upstream end of the study reach at Decatur to 5.2 milligrams per liter 12.2 miles downstream. Ammonia concentrations ranged from 45 milligrams per liter at the mouth of Stevens Creek (2.6 miles downstream from Decatur) to 0.03 milligram per liter at the downstream end of the study reach. Un-ionized ammonia concentrations exceeded the maximum concentration specified in the State water quality standard (0.04 milligram per liter) throughout most of the study reach. Model simulations indicated that oxidation of ammonia to form nitrite plus nitrate was the most significant process leading to low dissolved oxygen concentrations in the river. (USGS)

  9. Changes in the Synechococcus Assemblage Composition at the Surface of the East China Sea Due to Flooding of the Changjiang River.

    PubMed

    Chung, Chih-Ching; Gong, Gwo-Ching; Huang, Chin-Yi; Lin, Jer-Young; Lin, Yun-Chi

    2015-10-01

    The aim of this study was to elucidate how flooding of the Changjiang River affects the assemblage composition of phycoerythrin-rich (PE-rich) Synechococcus at the surface of the East China Sea (ECS). During non-flooding summers (e.g., 2009), PE-rich Synechococcus usually thrive at the outer edge of the Changjiang River diluted water coverage (CDW; salinity ≤31 PSU). In the summer of 2010, a severe flood occurred in the Changjiang River basin. The plentiful freshwater injection resulted in the expansion of the CDW over half of the ECS and caused PE-rich cells to show a uniform distribution pattern, with decreased abundance compared with the non-flooding summer. The phylogenetic diversity of 16S rRNA gene sequences indicated that the flooding event also shifted the picoplankton community composition from being dominated by Synechococcus, mainly attributed to the clade II lineage, to various orders of heterotrophic bacteria, including Actinobacteria, Flavobacteria, α-Proteobacteria, and γ-Proteobacteria. As an increasing number of studies have proposed that global warming might result in more frequent floods, combining this perspective with the information obtained from our previous [1] and this studies yield a more comprehensive understanding of the relationship between the composition of the marine Synechococcus assemblage and global environmental changes.

  10. Changes in the Synechococcus Assemblage Composition at the Surface of the East China Sea Due to Flooding of the Changjiang River.

    PubMed

    Chung, Chih-Ching; Gong, Gwo-Ching; Huang, Chin-Yi; Lin, Jer-Young; Lin, Yun-Chi

    2015-10-01

    The aim of this study was to elucidate how flooding of the Changjiang River affects the assemblage composition of phycoerythrin-rich (PE-rich) Synechococcus at the surface of the East China Sea (ECS). During non-flooding summers (e.g., 2009), PE-rich Synechococcus usually thrive at the outer edge of the Changjiang River diluted water coverage (CDW; salinity ≤31 PSU). In the summer of 2010, a severe flood occurred in the Changjiang River basin. The plentiful freshwater injection resulted in the expansion of the CDW over half of the ECS and caused PE-rich cells to show a uniform distribution pattern, with decreased abundance compared with the non-flooding summer. The phylogenetic diversity of 16S rRNA gene sequences indicated that the flooding event also shifted the picoplankton community composition from being dominated by Synechococcus, mainly attributed to the clade II lineage, to various orders of heterotrophic bacteria, including Actinobacteria, Flavobacteria, α-Proteobacteria, and γ-Proteobacteria. As an increasing number of studies have proposed that global warming might result in more frequent floods, combining this perspective with the information obtained from our previous [1] and this studies yield a more comprehensive understanding of the relationship between the composition of the marine Synechococcus assemblage and global environmental changes. PMID:25851446

  11. Projected changes in atmospheric rivers affecting Europe in CMIP5 models

    NASA Astrophysics Data System (ADS)

    Ramos, Alexandre M.; Tomé, Ricardo; Trigo, Ricardo M.; Liberato, Margarida L. R.; Pinto, Joaquim G.

    2016-09-01

    Atmospheric Rivers (ARs) are elongated bands of high water vapor concentration extending to the midlatitudes, which can be associated with intense precipitation and floods over continental areas. We analyze ARs reaching Europe in simulations from six Coupled Model Intercomparison Project Phase 5 (CMIP5) global climate models (GCMs) to quantify possible changes during the current century, with emphasis in five western European prone coastal areas. ARs are represented reasonably well in GCMs for recent climate conditions (1980-2005). Increased vertically integrated horizontal water transport is found for 2074-2099 (RCP4.5 and RCP8.5) compared to 1980-2005, while the number of ARs is projected to double on average for the same period. These changes are robust between models and are associated with higher air temperatures and thus enhanced atmospheric moisture content, together with higher precipitation associated with extratropical cyclones. This suggests an increased risk of intense precipitation and floods along the Atlantic European Coasts from the Iberian Peninsula to Scandinavia.

  12. Human health risk assessment via drinking water pathway due to metal contamination in the groundwater of Subarnarekha River Basin, India.

    PubMed

    Giri, Soma; Singh, Abhay Kumar

    2015-03-01

    Groundwater samples were collected from 30 sampling sites throughout the Subarnarekha River Basin for source apportionment and risk assessment studies. The concentrations of As, Ba, Cd, Cr, Co, Cu, Fe, Mn, Mo, Ni, Se, Sr, V and Zn were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The results demonstrated that concentrations of the metals showed significant spatial variation with some of the metals like As, Mn, Fe, Cu and Se exceeding the drinking water standards at some locations. Principal component analysis (PCA) outcome of four factors that together explained 84.99 % of the variance with >1 initial eigenvalue indicated that both innate and anthropogenic activities are contributing factors as source of metal in groundwater of Subarnarekha River Basin. Risk of metals on human health was then evaluated using hazard quotients (HQ) and cancer risk by ingestion for adult and child, and it was indicated that Mn was the most important pollutant leading to non-carcinogenic concerns. The carcinogenic risk of As for adult and child was within the acceptable cancer risk value of 1 × 10(-4). The largest contributors to chronic risks were Mn, Co and As. Considering the geometric mean concentration of metals, the hazard index (HI) for adult was above unity. Considering all the locations, the HI varied from 0.18 to 11.34 and 0.15 to 9.71 for adult and child, respectively, suggesting that the metals posed hazard by oral intake considering the drinking water pathway.

  13. Heavy metal contamination of agricultural soils affected by mining activities around the Ganxi River in Chenzhou, Southern China.

    PubMed

    Ma, Li; Sun, Jing; Yang, Zhaoguang; Wang, Lin

    2015-12-01

    Heavy metal contamination attracted a wide spread attention due to their strong toxicity and persistence. The Ganxi River, located in Chenzhou City, Southern China, has been severely polluted by lead/zinc ore mining activities. This work investigated the heavy metal pollution in agricultural soils around the Ganxi River. The total concentrations of heavy metals were determined by inductively coupled plasma-mass spectrometry. The potential risk associated with the heavy metals in soil was assessed by Nemerow comprehensive index and potential ecological risk index. In both methods, the study area was rated as very high risk. Multivariate statistical methods including Pearson's correlation analysis, hierarchical cluster analysis, and principal component analysis were employed to evaluate the relationships between heavy metals, as well as the correlation between heavy metals and pH, to identify the metal sources. Three distinct clusters have been observed by hierarchical cluster analysis. In principal component analysis, a total of two components were extracted to explain over 90% of the total variance, both of which were associated with anthropogenic sources. PMID:26547321

  14. Heavy metal contamination of agricultural soils affected by mining activities around the Ganxi River in Chenzhou, Southern China.

    PubMed

    Ma, Li; Sun, Jing; Yang, Zhaoguang; Wang, Lin

    2015-12-01

    Heavy metal contamination attracted a wide spread attention due to their strong toxicity and persistence. The Ganxi River, located in Chenzhou City, Southern China, has been severely polluted by lead/zinc ore mining activities. This work investigated the heavy metal pollution in agricultural soils around the Ganxi River. The total concentrations of heavy metals were determined by inductively coupled plasma-mass spectrometry. The potential risk associated with the heavy metals in soil was assessed by Nemerow comprehensive index and potential ecological risk index. In both methods, the study area was rated as very high risk. Multivariate statistical methods including Pearson's correlation analysis, hierarchical cluster analysis, and principal component analysis were employed to evaluate the relationships between heavy metals, as well as the correlation between heavy metals and pH, to identify the metal sources. Three distinct clusters have been observed by hierarchical cluster analysis. In principal component analysis, a total of two components were extracted to explain over 90% of the total variance, both of which were associated with anthropogenic sources.

  15. Evaluation of in-situ calibration of Chemcatcher passive samplers for 322 micropollutants in agricultural and urban affected rivers.

    PubMed

    Moschet, Christoph; Vermeirssen, Etiënne L M; Singer, Heinz; Stamm, Christian; Hollender, Juliane

    2015-03-15

    In a large field study, the in-situ calibration of the Chemcatcher(®) passive sampler - styrenedivinylbenzene (SDB) covered by a polyether sulfone (PES) membrane - was evaluated for 322 polar organic micropollutants. Five rivers with different agricultural and urban influences were monitored from March to July 2012 with two methods i) two-week time-proportional composite water samples and ii) two-week passive sampler deployment. All substances - from different substance classes with logKow -3 to 5, and neutral, anionic, cationic, and zwitterionic species - were analyzed by liquid-chromatography high-resolution tandem mass spectrometry. This study showed that SDB passive samplers are well-suited for the qualitative screening of polar micropollutants because the number of detected substances was similar (204 for SDB samples vs. 207 for composite water samples), limits of quantification were comparable (median: 1.3 ng/L vs. 1.6 ng/L), and the handling in the field and laboratory is fast and easy. The determination of in-situ calibrated sampling rates (field Rs) was possible for 88 compounds where the R(2) from the regression (water concentration vs. sampled mass on SDB disk) was >0.75. Substances with moderately fluctuating river concentrations such as pharmaceuticals showed much better correlations than substances with highly fluctuating concentrations such as pesticides (R(2) > 0.75 for 93% and 60% of the investigated substances, respectively). Flow velocity (0.05-0.8 m/s) and temperature (5-20 °C) did not have an evident effect on the field Rs. It was observed that ionic species had significantly lower field Rs than neutral species. Due to the complexity of the different transport processes, a correlation between determined field Rs and logDow could only predict Rs with large uncertainties. We conclude that only substances with relatively constant river concentrations can be quantified accurately in the field by passive sampling if substance-specific Rs are

  16. Shifts in vegetation affect organic carbon quality in a coastal marsh along the Hudson River Estuary

    NASA Astrophysics Data System (ADS)

    Zhang, A. H.; Corbett, J. E.; Tfaily, M. M.; Martin, I.; Ho, L.; Sun, E.; Sevilla, L.; Vincent, S.; Newton, R.; Peteet, D. M.

    2015-12-01

    To better understand carbon storage in coastal salt marshes, samples were collected from Piermont Marsh, NY (40 ̊00' N, 73 ̊55'W) located within the Hudson River Estuary. Porewater from three different vegetation sites was analyzed to compare the quality of the dissolved organic carbon. Sites contained either native or invasive vegetation with variations in live plant root depth. Porewater was taken from 0-3m in 50cm intervals, and sites were dominated either by invasive Phragmites australis, native Eleocharis , or native mixed vegetation (Spartina patens, Scirpus, and Typha angustifolia). Sites dominated by invasive Phragmites australis were found to have lower dissolved organic carbon (DOC) concentrations, lower cDOM absorption values, and more labile organic carbon compounds. The molecular composition of the DOC was determined with Fourier Transform Ion Cyclotron Mass Spectrometry (FT-ICR-MS). Labile DOC components were defined as proteins, carbohydrates, and amino sugars while recalcitrant DOC components were defined as lipids, unsaturated hydrocarbons, lignins, tannins, and condensed hydrocarbons. For the Phragmites, Eleocharis, and mixed vegetation sites, average DOC concentrations with depth were found to be 1.71 ± 1.06, 4.64 ± 1.73, and 4.62 ± 3.5 (mM), respectively and cDOM absorption values with depth were found to be 13.22 ± 4.81, 49.42 ± 10.8, and 35.74 ± 17.49 (m-1). Additionally, DOC concentrations increased with depth in the mixed vegetation and Eleocharis sites, but remained relatively constant in the Phragmites site. The percent of labile compounds in the surface samples were found to be 19.02, 14.64, and 14.07% for the Phragmites, Eleocharis, and mixed vegetation sites, respectively. These findings suggest that sites dominated by Phragmites may have more reactive DOC substrates than sites dominated by native vegetation. These results indicate that the carbon storage in marshes invaded by Phragmites would be expected to decrease over time.

  17. Tropical cyclone rainfall structure affecting indochina peninsula and lower mekong river basin (LMB)

    NASA Astrophysics Data System (ADS)

    CHHIN, Rattana; Joko Trilaksono, Nurjanna; Wahyu Hadi, Tri

    2016-08-01

    Indochina Peninsula is located in between Bay of Bengal (BoB) and South-China Sea (SCS). This region is affected frequently from Tropical Cyclones (TCs) formed in North Indian Ocean (NIO), South-China Sea (SCS), and North West Pacific Ocean (NWP). This research analyzed the structure of the rainfall over Indochina Peninsula and its relationships with TCs from the aforementioned sources. Principle Component Analysis (PCA) was performed to investigate the dominant rainfall area produced from those TCs. Spatial and Temporal structures of rainfall from the TCs is analyzed to understand their propagation. The results show that the dominant TC rainfall area covers Central Vietnam which contributed around 25% to total rainfall in the region. However, the contribution of this TC rainfall over LMB is likely less than 20% where Laos's territory receives highest contribution (20%). Furthermore, from the three source areas, TCs formed in SCS produce the highest rain rate when they develop into typhoon intensity stage of Joint Typhoon Warning Center (JTWC)’s scale. The average duration of TC rainfall over Indochina Peninsula is 81.28 hours, and over LMB is 66.22 hours. Thus, same as other regions in the Indochina Peninsula, LMB is affected by TC rainfall with considerable scales both spatially and temporally that may lead to significant hydrometeorological hazards.

  18. Metal mobility in river and sea sediments affected by mine drainage (Sestri Levante, Italy)

    NASA Astrophysics Data System (ADS)

    Consani, Sirio; Capello, Marco; Cutroneo, Laura; Vagge, Greta; Zuccarelli, Andrea; Carbone, Cristina

    2016-04-01

    The Gromolo Torrent is a metal-polluted Apennine streamflow located near Sestri Levante (Liguria, Italy). It springs from the Monte Rocca Grande (850 m a.s.l.), and flows for 11.5 km through the Gromolo Valley before flowing into the Ligurian Sea. Inside the Gromolo basin is located the abandoned Fe-Cu mine of Libiola, which was the most important sulfide deposit of the Ligurian Apennines. In this mining site, extensive Acid Mine Drainage (AMD) processes are active, both inside the mine tunnels and in the sulfide rich waste-rock dumps; the solutions generated are characterised by low pH values and high amounts of dissolved SO42-, Fe, and other chemical elements such as Cu, Zn, Pb, Al, Co, and Ni. Moreover, exstensively precipitation of Fe and Cu-rich secondary minerals occurs both as soft crusts inside the mine adits and as loose suspensions associated with overland flow of mine drainage. AMD waters flowed into the uncontaminated Gromolo Torrent where abundant precipitation of amorphous Fe(III)-oxy-hydroxides occurred. The marine study area is characterised by the presence of the headland of Sestri Levante with two bays, the western one named "Baia delle Favole". The dynamics of the area is dominated by a permanent north-westward off-shore current flowing approximately along isobath, and an eastward counter-current along the north coast with a resulting drift of the coastal materials from the West to Est towards "Baia delle Favole". The bottom sediment are principally characterised by coarse materials, mostly consisting of fine sand, with a percentage of the fine sediment increasing inside the bay, where the dynamics is low. The aims of this work are to 1) evaluate the metal mobility of colloidal river precipitates for about 7 km up to its mouth in the Ligurian Sea; 2) verify the contamination state of the marine bottom sediments off the mouth of the Gromolo Torrent ("Baia delle Favole" of Sestri Levante), and 3) identify the main sources and diffusion ways of

  19. New approach to mudflow formation as a 3D-process of interaction for surface water and groundwater due to base alimentation in the river basin

    NASA Astrophysics Data System (ADS)

    Trifonova, Tatiana; Arakelian, Mileta; Arakelian, Sergei

    2013-04-01

    ). Ground water is accumulated in the crack area; the mechanism of this 3D-process is connected with the inner (deep) pressure, as well as with capillary forces. For that, a certain area, called a mudflow gate, is being created in the river channel. This zone is the origin of an intensive ground feeding of the mudflow pulse (due to the pressure difference). It results in a sudden release of the ground water bringing in essential contribution to the surface phenomena. These processes are basic for forming a river basin, and have a permanent influence on the drainage network functioning. 4. Within the framework of this conception, as an example, we give a brief analysis of the possible reasons for the recent catastrophic flood in the town of Krimsk, Russia (July, 2012).

  20. Large wood budget assessment along a gravel bed river affected by volcanic eruption: the Rio Blanco study case (Chile).

    NASA Astrophysics Data System (ADS)

    Oss-Cazzador, Daniele; Iroume, Andres; Lenzi, Mario; Picco, Lorenzo

    2016-04-01

    Wood in riverine environments exerts different functions on ecological and geomorphic settings, influencing morphological processes, and increasing risks for sensitive structures. Large wood (LW) is defined as wood material, dead or alive, larger than 10 cm in diameter and 1 m in length. Natural hazards can strongly increase the presence of LW in waterways and flood events can transport it affecting the ecosystem and landscape. This study aims to increase the knowledge of wood budget, considering the effects of two subsequent slight flood events along a sub-reach of the Rio Blanco gravel bed river , in Chilean Patagonia, strongly affected by the eruption of Chaiten volcano in 2008. The volcanic eruption affected almost 3,5 km 2 of evergreen forest on the southern (left) bank, because of primary direct effects from pyroclastic density currents and lahar-floods that caused deposition up to 8 m of reworked tephra, alluvium, and wood on floodplains and terrace along the Rio Blanco. After the eruption, there was a considerable increase of LW into the main channel: into the bankfull channel, volume exceeds 100 m 3 /ha. Field surveys were carried out in January and March 2015, before and after two slight flood events (Recurrence Intervals lower than 1 year). The pre-event phase permitted to detect and analyze the presence of LW into the study area, along a 80 m-long reach of Rio Blanco (7500 m 2 . Every LW element was manually measured and described, a numbered metal tag was installed, and the position was recorded by GPS device. In January, there was a total amount of 113 m 3 /ha, 90% accumulated in LW jams (WJ) and 10% as single logs. The LW was characterized by mean dimensions of 3,36 m height, 0,25 m diameter and 0,26 m 3 volume, respectively. The WJ are characterized by wide range of dimension: volume varies from 0,28 m 3 to 672 m 3 , length from 1,20 m to 56 m, width from 0,40 m to 8,70 m and height from 0,20 m to 3 m, respectively. After the flood events, field

  1. Radium-226 and low pH in groundwater due to oxidation of authigenic pyrite; Savannah River Site, South Carolina

    SciTech Connect

    KUBILIUS, WALTER

    2005-12-21

    The origin of elevated radium-226 in groundwater beneath a sanitary landfill at the Savannah River Site (SRS) was investigated. Nearly one hundred monitoring wells are developed in the Steed Pond Aquifer (SPA), which consists of 100-150 ft of Coastal Plain sand, iron oxides, and minor clay. Wells screened in the upper and middle portions of the aquifer have average Ra-226 between 0.5 and 2.5 pCi/L, and average pHs above 4.7. However, wells screened near the base of the aquifer exhibit higher average Ra-226 concentrations of 2.5 to 4.6 pCi/L, with some measurements exceeding the MCL of 5 pCi/L, and show average pHs of 4.1 to 4.7. These wells are not downgradient of the landfill, and are not impacted by landfill leachate. The Crouch Branch Confining Unit (CBCU) underlies the aquifer, and is composed partly of reduced gray/brown clay with lignite and authigenic pyrite. Gamma ray logs show that the SPA has low gamma counts, but the CBCU is consistently elevated. Groundwater with high radium/low pH also contains elevated sulfate concentrations. pH calculations indicate that sulfate is in the form of sulfuric acid. A model for the origin of elevated Ra-226 levels in deeper SPA wells envisions infiltration of oxygenated SPA groundwater into reduced pyritic CBCU sediments, with consequent oxidative pyrite dissolution, and acidification of groundwater. Then, naturally occurring CBCU radium dissolves, and mixes into the Steed Pond Aquifer.

  2. Global River Flood Exposure Assessment Under Climate Change: How Many Asians Are Affected By Flood in the Future?

    NASA Astrophysics Data System (ADS)

    Kwak, Y.; Iwami, Y.

    2014-12-01

    Physical exposure assessment in this study shows a methodological possibility to be used as a preliminary case study based on a global approach for flood risk assessment consisting of hazard, exposure, and vulnerability. The purpose of this preliminary study is to estimate potential flood inundation areas as a hazard (both present and future condition), and flood exposure change over the Asia region with consideration of climate change impacts. A flood hazard was characterized by inundation area at the high-resolution of 500 m, location (lowland around rivers), and probability (floods with the 50-year return period). This study introduced a new approach to moderate the global flood hazard and the exposure calculation with significant limitations of current models for continental-scale flood risk assessment by using the flood inundation depth (FID) model based on Manning's steady, uniform flow resistance formula in extreme case during 25-year simulations based on the global BTOP distributed hydrological model using precipitations from the MRI-AGCM 3.2S with SRES A1B emissions scenarios for present-day (daily data from 1980 to 2004), and end-of-the-21st century (daily data from 2075 to 2099). It effectively simplified the complexity between hydrological and topological variables in a flood risk-prone area with assumption of the effects of natural or artificial levees. Exposure was obtained by combining the hazards at the same resolution to identify affected population by calculating with urbanization ratio and population change ratio of Asian countries from a distributed data of global population (Landscan by the Oak Ridge National Laboratory). As a result of the physical exposure assessment from present to the end-of-the-21st century, potential hazards area and affected population are projected to increase 4.2 % (approximately 75,900 km2) and 3.4 % (approximately 35.1 million people) respectively, because Asian population increases about 43% in the future. We found

  3. How do long-term development and periodical changes of river-floodplain systems affect the fate of contaminants? Results from European rivers.

    PubMed

    Lair, G J; Zehetner, F; Fiebig, M; Gerzabek, M H; van Gestel, C A M; Hein, T; Hohensinner, S; Hsu, P; Jones, K C; Jordan, G; Koelmans, A A; Poot, A; Slijkerman, D M E; Totsche, K U; Bondar-Kunze, E; Barth, J A C

    2009-12-01

    In many densely populated areas, riverine floodplains have been strongly impacted and degraded by river channelization and flood protection dikes. Floodplains act as buffers for flood water and as filters for nutrients and pollutants carried with river water and sediment from upstream source areas. Based on results of the EU-funded "AquaTerra" project (2004-2009), we analyze changes in the dynamics of European river-floodplain systems over different temporal scales and assess their effects on contaminant behaviour and ecosystem functioning. We find that human-induced changes in the hydrologic regime of rivers have direct and severe consequences on nutrient cycling and contaminant retention in adjacent floodplains. We point out the complex interactions of contaminants with nutrient availability and other physico-chemical characteristics (pH, organic matter) in determining ecotoxicity and habitat quality, and draw conclusions for improved floodplain management.

  4. How do long-term development and periodical changes of river-floodplain systems affect the fate of contaminants? Results from European rivers.

    PubMed

    Lair, G J; Zehetner, F; Fiebig, M; Gerzabek, M H; van Gestel, C A M; Hein, T; Hohensinner, S; Hsu, P; Jones, K C; Jordan, G; Koelmans, A A; Poot, A; Slijkerman, D M E; Totsche, K U; Bondar-Kunze, E; Barth, J A C

    2009-12-01

    In many densely populated areas, riverine floodplains have been strongly impacted and degraded by river channelization and flood protection dikes. Floodplains act as buffers for flood water and as filters for nutrients and pollutants carried with river water and sediment from upstream source areas. Based on results of the EU-funded "AquaTerra" project (2004-2009), we analyze changes in the dynamics of European river-floodplain systems over different temporal scales and assess their effects on contaminant behaviour and ecosystem functioning. We find that human-induced changes in the hydrologic regime of rivers have direct and severe consequences on nutrient cycling and contaminant retention in adjacent floodplains. We point out the complex interactions of contaminants with nutrient availability and other physico-chemical characteristics (pH, organic matter) in determining ecotoxicity and habitat quality, and draw conclusions for improved floodplain management. PMID:19604610

  5. Significant cooling effect on the surface due to soot particles over Brahmaputra River Valley region, India: An impact on regional climate.

    PubMed

    Tiwari, S; Kumar, R; Tunved, P; Singh, S; Panicker, A S

    2016-08-15

    Black carbon (BC) is an important atmospheric aerosol constituent that affects the climate by absorbing (directly) the sunlight and modifying cloud characteristics (indirectly). Here, we present first time yearlong measurements of BC and carbon monoxide (CO) from an urban location of Guwahati located in the Brahmaputra River valley (BRV) in the northeast region of India from 1st July 2013 to 30th June 2014. Daily BC concentrations varied within the range of 2.86 to 11.56μgm(-3) with an annual average of 7.17±1.89μgm(-3), while, CO varied from 0.19 to 1.20ppm with a mean value of 0.51±0.19ppm during the study period. The concentrations of BC (8.37μgm(-3)) and CO (0.67ppm) were ~39% and ~55% higher during the dry months (October to March) than the wet months (April to September) suggesting that seasonal changes in meteorology and emission sources play an important role in controlling these species. The seasonal ΔBC/ΔCO ratios were highest (lowest) in the pre-monsoon (winter) 18.1±1.4μgm(-3)ppmv(-1) (12.6±2.2μgm(-3)ppmv(-1)) which indicate the combustion of biofuel/biomass as well as direct emissions from fossil fuel during the pre-monsoon season. The annual BC emission was estimated to be 2.72Gg in and around Guwahati which is about 44% lower than the mega city 'Delhi' (4.86Gg). During the study period, the annual mean radiative forcing (RF) at the top of the atmosphere (TOA) for clear skies of BC was +9.5Wm(-2), however, the RF value at the surface (SFC) was -21.1Wm(-2) which indicates the net warming and cooling effects, respectively. The highest RF at SFC was in the month of April (-30Wm(-2)) which is coincident with the highest BC mass level. The BC atmospheric radiative forcing (ARF) was +30.16 (annual mean) Wm(-2) varying from +23.1 to +43.8Wm(-2). The annual mean atmospheric heating rate (AHR) due to the BC aerosols was 0.86Kday(-1) indicates the enhancement in radiation effect over the study region. The Weather Research and Forecasting model

  6. Significant cooling effect on the surface due to soot particles over Brahmaputra River Valley region, India: An impact on regional climate.

    PubMed

    Tiwari, S; Kumar, R; Tunved, P; Singh, S; Panicker, A S

    2016-08-15

    Black carbon (BC) is an important atmospheric aerosol constituent that affects the climate by absorbing (directly) the sunlight and modifying cloud characteristics (indirectly). Here, we present first time yearlong measurements of BC and carbon monoxide (CO) from an urban location of Guwahati located in the Brahmaputra River valley (BRV) in the northeast region of India from 1st July 2013 to 30th June 2014. Daily BC concentrations varied within the range of 2.86 to 11.56μgm(-3) with an annual average of 7.17±1.89μgm(-3), while, CO varied from 0.19 to 1.20ppm with a mean value of 0.51±0.19ppm during the study period. The concentrations of BC (8.37μgm(-3)) and CO (0.67ppm) were ~39% and ~55% higher during the dry months (October to March) than the wet months (April to September) suggesting that seasonal changes in meteorology and emission sources play an important role in controlling these species. The seasonal ΔBC/ΔCO ratios were highest (lowest) in the pre-monsoon (winter) 18.1±1.4μgm(-3)ppmv(-1) (12.6±2.2μgm(-3)ppmv(-1)) which indicate the combustion of biofuel/biomass as well as direct emissions from fossil fuel during the pre-monsoon season. The annual BC emission was estimated to be 2.72Gg in and around Guwahati which is about 44% lower than the mega city 'Delhi' (4.86Gg). During the study period, the annual mean radiative forcing (RF) at the top of the atmosphere (TOA) for clear skies of BC was +9.5Wm(-2), however, the RF value at the surface (SFC) was -21.1Wm(-2) which indicates the net warming and cooling effects, respectively. The highest RF at SFC was in the month of April (-30Wm(-2)) which is coincident with the highest BC mass level. The BC atmospheric radiative forcing (ARF) was +30.16 (annual mean) Wm(-2) varying from +23.1 to +43.8Wm(-2). The annual mean atmospheric heating rate (AHR) due to the BC aerosols was 0.86Kday(-1) indicates the enhancement in radiation effect over the study region. The Weather Research and Forecasting model

  7. Potential mitigation approach to minimize salinity intrusion in the Lower Savannah River Estuary due to reduced controlled releases from Lake Thurmond

    USGS Publications Warehouse

    Conrads, Paul A.; Greenfield, James M.

    2010-01-01

    The Savannah River originates at the confluence of the Seneca and Tugaloo Rivers, near Hartwell, Ga. and forms the State boundary between South Carolina and Georgia. The J. Strom Thurmond Dam and Lake, located 187 miles upstream from the coast, is responsible for most of the flow regulation that affects the Savannah River from Augusta to the coast. The Savannah Harbor experiences semi-diurnal tides of two high and two low tides in a 24.8-hour period with pronounced differences in tidal range between neap and spring tides occurring on a 14-day and 28-day lunar cycle. The Savannah National Wildlife Refuge is located in the Savannah River Estuary. The tidal freshwater marsh is an essential part of the 28,000-acre refuge and is home to a diverse variety of wildlife and plant communities. The Southeastern U.S. experienced severe drought conditions in 2008 and if the conditions had persisted in Georgia and South Carolina, Thurmond Lake could have reached an emergency operation level where outflow from the lake is equal to the inflow to the lake. To decrease the effect of the reduced releases on downstream resources, a stepped approach was proposed to reduce the flow in increments of 500 cubic feet per second (ft3/s) intervals. Reduced flows from 3,600 ft3/s to 3,100 ft3/s and 2,600 ft3/s were simulated with two previously developed models of the Lower Savannah River Estuary to evaluate the potential effects on salinity intrusion. The end of the previous drought (2002) was selected as the baseline condition for the simulations with the model. Salinity intrusion coincided with the 28-day cycle semidiurnal tidal cycles. The results show a difference between the model simulations of how the salinity will respond to the decreased flows. The Model-to-Marsh Decision Support System (M2MDSS) salinity response shows a large increase in the magnitude (> 6.0 practical salinity units, psu) and duration (3-4 days) of the salinity intrusion with extended periods (21 days) of tidal

  8. Factors Affecting Route Selection and Survival of Steelhead Kelts at Snake River Dams in 2012 and 2013

    SciTech Connect

    Harnish, Ryan A.; Colotelo, Alison HA; Li, Xinya; Ham, Kenneth D.; Deng, Zhiqun

    2014-12-01

    turbines. The side of the river in which kelts approached the dam and dam operations also affected route of passage. Dam operations and the size and condition of kelts were found to have the greatest effect on route-specific survival probabilities for fish that passed via the spillway at LGS. That is, longer kelts and those in fair condition had a lower probability of survival for fish that passed via the spillway weir. The survival of spillway weir- and deep-spill passed kelts was positively correlated with the percent of the total discharge that passed through turbine unit 4. Too few kelts passed through the traditional spill, JBS, and turbine units to evaluate survival through these routes. The information gathered in this study describes Snake River steelhead kelt passage behavior, rates, and distributions through the FCRPS as well as provide information to biologists and engineers about the dam operations and abiotic conditions that are related to passage and survival of steelhead kelts.

  9. The upside-down river: Reservoirs, algal blooms, and tributaries affect temporal and spatial patterns in nitrogen and phosphorus in the Klamath River, USA

    NASA Astrophysics Data System (ADS)

    Oliver, Allison A.; Dahlgren, Randy A.; Deas, Michael L.

    2014-11-01

    The Klamath River, located in Oregon/California of the Northwestern U.S., is highly impounded and also experiences large seasonal algal blooms and impaired water quality. We investigated nitrogen (N) and phosphorus (P) constituents for one year (2010-2011) across 193 km of the Klamath River at sites above and below reservoirs and major tributaries to determine the influence of these features on longitudinal and temporal trends in concentrations, loads, and N:P ratios. In general, the headwater lake (Upper Klamath Lake) and reservoirs appeared to be the dominant influence on water quality and nutrient dynamics in the upper river, whereas tributaries appeared to exert stronger influence in the lower river. Overall, high nutrients and poor water quality at upstream sites were ameliorated downstream, however the downstream reductions in N were much greater relative to P. Seasonality appeared to play a major role in the overall appearance and magnitude of longitudinal trends. The greatest upstream-downstream differences occurred during periods of time following large algal blooms in the upper portion of the river. Overall, the amount and composition of N appeared to be strongly driven by algal blooms and biogeochemical conditions such as low oxygen, high pH and warm temperatures in the upper portion of the river, whereas P was more strongly driven by seasonal hydrology. The spatiotemporal influence of reservoirs and tributaries on nutrient flux and nutrient ratios may have significant implications for aquatic communities and ecosystem health. Nutrient objectives should be considered when designing restoration, management, and monitoring objectives for projects involving habitat suitability for anadromous fish and potential dam removal.

  10. Factors affecting the occurrence of saugers in small, high-elevation rivers near the western edge of the species' natural distribution

    USGS Publications Warehouse

    Amadio, C.J.; Hubert, W.A.; Johnson, K.; Oberlie, D.; Dufek, D.

    2005-01-01

    Factors affecting the occurrence of saugers Sander canadensis were studied throughout the Wind River basin, a high-elevation watershed (> 1,440 m above mean sea level) on the western periphery of the species' natural distribution in central Wyoming. Adult saugers appeared to have a contiguous distribution over 170 km of streams among four rivers in the watershed. The upstream boundaries of sauger distribution were influenced by summer water temperatures and channel slopes in two rivers and by water diversion dams that created barriers to upstream movement in the other two rivers. Models that included summer water temperature, maximum water depth, habitat type (pool or run), dominant substrate, and alkalinity accounted for the variation in sauger occurrence across the watershed within the areas of sauger distribution. Water temperature was the most important basin-scale habitat feature associated with sauger occurrence, and maximum depth was the most important site-specific habitat feature. Saugers were found in a larger proportion of pools than runs in all segments of the watershed and occurred almost exclusively in pools in upstream segments of the watershed. Suitable summer water temperatures and deep, low-velocity habitat were available to support saugers over a large portion of the Wind River watershed. Future management of saugers in the Wind River watershed, as well as in other small river systems within the species' native range, should involve (1) preserving natural fluvial processes to maintain the summer water temperatures and physical habitat features needed by saugers and (2) assuring that barriers to movement do not reduce upstream boundaries of populations.

  11. First data on the uranium content in water of the Yenisei River basin in the area affected by the operation of Rosatom plants

    NASA Astrophysics Data System (ADS)

    Bolsunovskii, A. Ya.; Zhizhaev, A. M.; Saprykin, A. I.; Degermendzhi, A. G.; Rubailo, A. I.

    2011-07-01

    This study is devoted to investigating the content of uranium isotopes in water of the Yenisei River and its tributaries within the territories affected by the operation of Rosatom plants (mining chemical combine, and electrochemical plant). Long-term monitoring of the 238U content by mass spectrometry carried out in two institutes of the Siberian Branch of the Russian Academy of Sciences first revealed the multiple excess of 238U over the background content in different areas of the Yenisei River basin, such as the region of the Yenisei River near the effluents of the mining and chemical combine (MCC), and the territories of the Bol'shaya Tel' and Kan rivers. In these regions, the 238U content in water reaches 2.1-4.0 μg/l, which exceeds its content upstream from the MCC (0.3-0.6 μg/l) by almost an order of magnitude. The studies of the isotopic composition of uranium in water samples, which were carried out at the Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, showed the presence of a technogenic isotope of uranium 236U in the samples from the Bolshaya Tel' River and revealed the deviation of the isotope ratio 238U/235U (167 ± 3 and 177 ± 3) from the equilibrium natural ratio (238U/235U = 138). These facts attest to the technogenic origin of part of the uranium in water of the Bol'shaya Tel' River connected with the activity of MCC. The excess uranium content in the Kan River requires additional studies to ascertain the fraction of uranium of technogenic origin connected with the activity of the electrochemical plant (ECP) (Fig. 1, Table 4).

  12. Preliminary estimate of possible flood elevations in the Columbia River at Trojan Nuclear Power Plant due to failure of debris dam blocking Spirit Lake, Washington

    USGS Publications Warehouse

    Kresch, D.L.; Laenen, Antonius

    1984-01-01

    Failure of the debris dam, blocking the outflow of Spirit Lake near Mount St. Helens, could result in a mudflow down the Toutle and Cowlitz Rivers into the Columbia River. Flood elevations at the Trojan Nuclear Power Plant on the Columbia River, 5 mi upstream from the Cowlitz River, were simulated with a hydraulic routing model. The simulations are made for four Columbia River discharges in each of two scenarios, one in which Columbia River floods coincide with a mudflow and the other in which Columbia River floods follow a mudflow sediment deposit upstream from the Cowlitz River. In the first scenario, Manning 's roughness coefficients for clear water and for mudflow in the Columbia River are used; in the second scenario only clear water coefficients are used. The grade elevation at the power plant is 45 ft above sea level. The simulated elevations exceed 44 ft if the mudflow coincides with a Columbia River discharge that has a recurrence interval greater than 10 years (610,000 cu ft/sec); the mudflow is assumed to extend downstream from the Cowlitz River to the mouth of the Columbia River, and Manning 's roughness coefficients for a mudflow are used. The simulated elevation is 32 ft if the mudflow coincides with a 100-yr flood (820,000 cu ft/sec) and clear-water Manning 's coefficients are used throughout the entire reach of the Columbia River. The elevations exceed 45 ft if a flow exceeding the 2-yr peak discharge in the Columbia River (410,000 cu ft/sec) follows the deposit of 0.5 billion cu yd of mudflow sediment upstream of the Cowlitz River before there has been any appreciable scour or dredging of the deposit. In this simulation it is assumed that: (1) the top of the sediment deposited in the Columbia River is at an elevation of 30 ft at the mouth of the Cowlitz River, (2) the surface elevation of the sediment deposit decreases in an upstream direction at a rate of 2.5 ft/mi, and (3) clear water Manning 's coefficients apply to the entire modeled reach of

  13. Upstream factors affecting Tualatin River algae—Tracking the 2008 Anabaena algae bloom to Wapato Lake, Oregon

    USGS Publications Warehouse

    Rounds, Stewart A.; Carpenter, Kurt D.; Fesler, Kristel J.; Dorsey, Jessica L.

    2015-01-01

    The results and insights derived from this study can be used to enhance future monitoring and data collection strategies designed to improve water quality and plankton models and better predict dissolved-oxygen concentrations in the lower Tualatin River.

  14. Upstream factors affecting Tualatin River algae—Tracking the 2008 Anabaena algae bloom to Wapato Lake, Oregon

    USGS Publications Warehouse

    Rounds, Stewart A.; Carpenter, Kurt D.; Fesler, Kristel J.; Dorsey, Jessica L.

    2015-12-17

    The results and insights derived from this study can be used to enhance future monitoring and data collection strategies designed to improve water quality and plankton models and better predict dissolved-oxygen concentrations in the lower Tualatin River.

  15. Geomorphological and geotechnical issues affecting the seismic slope stability of the Duwamish River Delta, Port of Seattle, Washington

    USGS Publications Warehouse

    Kayen, Robert E.; Barnhardt, Walter A.; Palmer, Stephen P.

    1999-01-01

    Young Holocene deposits of the Duwamish River valley underlie a highly developed transportation-industrial corridor, extending from the City of Kent to the Elliott Bay-Harbor Island marine terminal facilities. The deposits have been shaped by relative sea-level rise, but also by episodic volcanism and seismicity. A geologic and geotechnical investigation of these river-mouth deposits indicates high initial liquefaction susceptibility during earthquakes, and possibly the potential for unlimited-strain disintegrative flow failure of the delta front.

  16. Physicochemical Characteristics of the Hyporheic Zone Affect Redd Site Selection of Chum and Fall Chinook Salmon, Columbia River.

    SciTech Connect

    Geist, David R.

    2001-10-01

    Chum salmon (Oncorhynchus keta) may historically have been the most abundant species of Columbia River salmon, contributing as much as 50% of the total biomass of all salmon in the Pacific Ocean prior to the 1940's (Neave 1961). By the 1950's, however, run sizes to the Columbia River dropped dramatically and in 1999 the National Marine Fisheries Service (NMFS) listed Columbia River chum salmon as threatened under the Endangered Species Act (ESA; NMFS 1999). Habitat degradation, water diversions, harvest, and artificial propagation are the major human-induced factors that have contributed to the species decline (NMFS 1998). Columbia River chum salmon spawn exclusively in the lower river below Bonneville Dam, including an area near Ives Island. The Ives Island chum salmon are part of the Columbia River evolutionary significant unit (ESU) for this species, and are included in the ESA listing. In addition to chum salmon, fall chinook salmon (O. tshawytscha) also spawn at Ives Island. Spawning surveys conducted at Ives Island over the last several years show that chum and fall chinook salmon spawned in clusters in different locations (US Fish and Wildlife Service and Washington Department of Fish and Wildlife, unpublished data). The presence of redd clusters suggested that fish were selecting specific habitat features within the study area (Geist and Dauble 1998). Understanding the specific features of these spawning areas is needed to quantify the amount of habitat available to each species so that minimum flows can be set to protect fish and maintain high quality habitat.

  17. Water discharge affects Atlantic salmon Salmo salar smolt production: a 27 year study in the River Orkla, Norway.

    PubMed

    Hvidsten, N A; Diserud, O H; Jensen, A J; Jensås, J G; Johnsen, B O; Ugedal, O

    2015-01-01

    A model that explains 48% of the annual variation in Atlantic salmon Salmo salar smolt production in the River Orkla, Norway, has been established. This variation could be explained by egg deposition, minimum daily discharge during the previous winter and minimum weekly discharge during the summer 3 years before smolt migration. All coefficients in the model were positive, which indicates that more eggs and higher minimum discharge levels during the winter before smolt migration and the summer after hatching benefit smolt production. Hence, when the spawning target of the river is reached, the minimum levels of river discharge, in both winter and summer, are the main bottlenecks for the parr survival, and hence for smolt production. The River Orkla was developed for hydropower production in the early 1980s by the construction of four reservoirs upstream of the river stretch accessible to S. salar. Although no water has been removed from the catchment, the dynamics of water flow has been altered, mainly by increasing discharges during winter and reducing spring floods. In spite of the higher than natural winter discharges, minimum winter discharge is still a determinant of smolt production. Hence, in regulated rivers, the maintenance of discharges to ensure that they are as high as possible during dry periods is an important means of securing high S. salar smolt production.

  18. Water discharge affects Atlantic salmon Salmo salar smolt production: a 27 year study in the River Orkla, Norway.

    PubMed

    Hvidsten, N A; Diserud, O H; Jensen, A J; Jensås, J G; Johnsen, B O; Ugedal, O

    2015-01-01

    A model that explains 48% of the annual variation in Atlantic salmon Salmo salar smolt production in the River Orkla, Norway, has been established. This variation could be explained by egg deposition, minimum daily discharge during the previous winter and minimum weekly discharge during the summer 3 years before smolt migration. All coefficients in the model were positive, which indicates that more eggs and higher minimum discharge levels during the winter before smolt migration and the summer after hatching benefit smolt production. Hence, when the spawning target of the river is reached, the minimum levels of river discharge, in both winter and summer, are the main bottlenecks for the parr survival, and hence for smolt production. The River Orkla was developed for hydropower production in the early 1980s by the construction of four reservoirs upstream of the river stretch accessible to S. salar. Although no water has been removed from the catchment, the dynamics of water flow has been altered, mainly by increasing discharges during winter and reducing spring floods. In spite of the higher than natural winter discharges, minimum winter discharge is still a determinant of smolt production. Hence, in regulated rivers, the maintenance of discharges to ensure that they are as high as possible during dry periods is an important means of securing high S. salar smolt production. PMID:25418585

  19. Comparison of two methods for estimating discharge and nutrient loads from Tidally affected reaches of the Myakka and Peace Rivers, West-Central Florida

    USGS Publications Warehouse

    Levesque, V.A.; Hammett, K.M.

    1997-01-01

    The Myakka and Peace River Basins constitute more than 60 percent of the total inflow area and contribute more than half the total tributary inflow to the Charlotte Harbor estuarine system. Water discharge and nutrient enrichment have been identified as significant concerns in the estuary, and consequently, it is important to accurately estimate the magnitude of discharges and nutrient loads transported by inflows from both rivers. Two methods for estimating discharge and nutrient loads from tidally affected reaches of the Myakka and Peace Rivers were compared. The first method was a tidal-estimation method, in which discharge and nutrient loads were estimated based on stage, water-velocity, discharge, and water-quality data collected near the mouths of the rivers. The second method was a traditional basin-ratio method in which discharge and nutrient loads at the mouths were estimated from discharge and loads measured at upstream stations. Stage and water-velocity data were collected near the river mouths by submersible instruments, deployed in situ, and discharge measurements were made with an acoustic Doppler current profiler. The data collected near the mouths of the Myakka River and Peace River were filtered, using a low-pass filter, to remove daily mixed-tide effects with periods less than about 2 days. The filtered data from near the river mouths were used to calculate daily mean discharge and nutrient loads. These tidal-estimation-method values were then compared to the basin-ratio-method values. Four separate 30-day periods of differing streamflow conditions were chosen for monitoring and comparison. Discharge and nutrient load estimates computed from the tidal-estimation and basin-ratio methods were most similar during high-flow periods. However, during high flow, the values computed from the tidal-estimation method for the Myakka and Peace Rivers were consistently lower than the values computed from the basin-ratio method. There were substantial

  20. Simulations of groundwater-surface water interaction and particle movement due to the effect of weir construction in the sub-watershed of the river Labe in the town of Děčín.

    PubMed

    Matula, S; Mekonnen, G B; Báťková, K; Nešetřil, K

    2014-11-01

    Steady- and transient-state simulations of groundwater flow and particle movement in the sub-watershed of the river Labe in Děčín town was carried out using Visual MODFLOW software. The simulations were performed for calibration and for the scenarios that the change in the water level of the river Labe was undergoing. Steady-state simulation was carried out for the sake of calibration of model outputs. For transient simulation, two different scenarios were considered in order to investigate the response of the aquifer system to the stresses applied on surface water of the river. The simulation results have shown that the surface water and groundwater interactions, and the subsequent particle movement were affected by the stresses applied on the surface water in the river Labe. The first scenario involved the rapid recharge of surface water to the aquifer in the vicinity of the river while particles still move towards the river at the places far away from the river. At the end of the second scenario, particles still tend to move towards the river slowly and finally tend to stay within the aquifer as equilibrium of hydraulic gradient is reached between the surface and groundwater levels. The time series graphs of hydraulic heads at all observation wells show that the groundwater level in the surrounding aquifer rises significantly as a result of recharges from the river. The local water balance of the study area was calculated and expressed as the rates of water entering and leaving the system. At the end of the second scenario, the difference between the rate of flow into and out of the model area was 0.73 m(3) day(-1).

  1. Natural and anthropogenic factors affecting the groundwater quality in the Nandong karst underground river system in Yunan, China.

    PubMed

    Jiang, Yongjun; Wu, Yuexia; Groves, Chris; Yuan, Daoxian; Kambesis, Pat

    2009-10-13

    The Nandong Underground River System (NURS) is located in a typical karst agriculture dominated area in the southeast Yunnan Province, China. Groundwater plays an important role for social and economical development in the area. However, with the rapid increase in population and expansion of farm land, groundwater quality has degraded. 42 groundwater samples collected from springs in the NURS showed great variation of chemical compositions across the study basin. With increased anthropogenic contamination in the area, the groundwater chemistry has changed from the typical Ca-HCO(3) or Ca (Mg)-HCO(3) type in karst groundwater to the Ca-Cl (+NO(3)) or Ca (Mg)-Cl (+NO(3)), and Ca-Cl (+NO(3)+SO(4)) or Ca (Mg)-Cl (+NO(3)+SO(4)) type, indicating increases in NO(3)(-), Cl(-) and SO(4)(2-) concentrations that were caused most likely by human activities in the region. This study implemented the R-mode factor analysis to investigate the chemical characteristics of groundwater and to distinguish the natural and anthropogenic processes affecting groundwater quality in the system. The R-mode factor analysis together with geology and land uses revealed that: (a) contamination from human activities such as sewage effluents and agricultural fertilizers; (b) water-rock interaction in the limestone-dominated system; and (c) water-rock interaction in the dolomite-dominated system were the three major factors contributing to groundwater quality. Natural dissolution of carbonate rock (water-rock interaction) was the primary source of Ca(2+) and HCO(3)(-) in groundwater, water-rock interaction in dolomite-dominated system resulted in higher Mg(2+) in the groundwater, and human activities were likely others sources. Sewage effluents and fertilizers could be the main contributor of Cl(-), NO(3)(-), SO(4)(2-), Na(+) and K(+) to the groundwater system in the area. This study suggested that both natural and anthropogenic processes contributed to chemical composition of groundwater in the

  2. Natural and anthropogenic factors affecting the groundwater quality in the Nandong karst underground river system in Yunan, China.

    PubMed

    Jiang, Yongjun; Wu, Yuexia; Groves, Chris; Yuan, Daoxian; Kambesis, Pat

    2009-10-13

    The Nandong Underground River System (NURS) is located in a typical karst agriculture dominated area in the southeast Yunnan Province, China. Groundwater plays an important role for social and economical development in the area. However, with the rapid increase in population and expansion of farm land, groundwater quality has degraded. 42 groundwater samples collected from springs in the NURS showed great variation of chemical compositions across the study basin. With increased anthropogenic contamination in the area, the groundwater chemistry has changed from the typical Ca-HCO(3) or Ca (Mg)-HCO(3) type in karst groundwater to the Ca-Cl (+NO(3)) or Ca (Mg)-Cl (+NO(3)), and Ca-Cl (+NO(3)+SO(4)) or Ca (Mg)-Cl (+NO(3)+SO(4)) type, indicating increases in NO(3)(-), Cl(-) and SO(4)(2-) concentrations that were caused most likely by human activities in the region. This study implemented the R-mode factor analysis to investigate the chemical characteristics of groundwater and to distinguish the natural and anthropogenic processes affecting groundwater quality in the system. The R-mode factor analysis together with geology and land uses revealed that: (a) contamination from human activities such as sewage effluents and agricultural fertilizers; (b) water-rock interaction in the limestone-dominated system; and (c) water-rock interaction in the dolomite-dominated system were the three major factors contributing to groundwater quality. Natural dissolution of carbonate rock (water-rock interaction) was the primary source of Ca(2+) and HCO(3)(-) in groundwater, water-rock interaction in dolomite-dominated system resulted in higher Mg(2+) in the groundwater, and human activities were likely others sources. Sewage effluents and fertilizers could be the main contributor of Cl(-), NO(3)(-), SO(4)(2-), Na(+) and K(+) to the groundwater system in the area. This study suggested that both natural and anthropogenic processes contributed to chemical composition of groundwater in the

  3. Natural and anthropogenic factors affecting the groundwater quality in the Nandong karst underground river system in Yunan, China

    NASA Astrophysics Data System (ADS)

    Jiang, Yongjun; Wu, Yuexia; Groves, Chris; Yuan, Daoxian; Kambesis, Pat

    2009-10-01

    The Nandong Underground River System (NURS) is located in a typical karst agriculture dominated area in the southeast Yunnan Province, China. Groundwater plays an important role for social and economical development in the area. However, with the rapid increase in population and expansion of farm land, groundwater quality has degraded. 42 groundwater samples collected from springs in the NURS showed great variation of chemical compositions across the study basin. With increased anthropogenic contamination in the area, the groundwater chemistry has changed from the typical Ca-HCO 3 or Ca (Mg)-HCO 3 type in karst groundwater to the Ca-Cl (+ NO 3) or Ca (Mg)-Cl (+ NO 3), and Ca-Cl (+ NO 3 + SO 4) or Ca (Mg)-Cl (+ NO 3 + SO 4) type, indicating increases in NO 3-, Cl - and SO 42- concentrations that were caused most likely by human activities in the region. This study implemented the R-mode factor analysis to investigate the chemical characteristics of groundwater and to distinguish the natural and anthropogenic processes affecting groundwater quality in the system. The R-mode factor analysis together with geology and land uses revealed that: (a) contamination from human activities such as sewage effluents and agricultural fertilizers; (b) water-rock interaction in the limestone-dominated system; and (c) water-rock interaction in the dolomite-dominated system were the three major factors contributing to groundwater quality. Natural dissolution of carbonate rock (water-rock interaction) was the primary source of Ca 2+ and HCO 3- in groundwater, water-rock interaction in dolomite-dominated system resulted in higher Mg 2+ in the groundwater, and human activities were likely others sources. Sewage effluents and fertilizers could be the main contributor of Cl -, NO 3-, SO 42-, Na + and K + to the groundwater system in the area. This study suggested that both natural and anthropogenic processes contributed to chemical composition of groundwater in the NURS, human activities

  4. Survey context and question wording affects self reported annoyance due to road traffic noise: a comparison between two cross-sectional studies

    PubMed Central

    2012-01-01

    Background Surveys are a common way to measure annoyance due to road traffic noise, but the method has some draw-backs. Survey context, question wording and answer alternatives could affect participation and answers and could have implications when comparing studies and/or performing pooled analyses. The aim of this study was to investigate the difference in annoyance reporting due to road traffic noise in two types of surveys of which one was introduced broadly and the other with the clearly stated aim of investigating noise and health. Methods Data was collected from two surveys carried out in the municipality of Malmö, southern Sweden in 2007 and 2008 (n = 2612 and n = 3810). The first survey stated an aim of investigating residential environmental exposure, especially noise and health. The second survey was a broad public health survey stating a broader aim. The two surveys had comparable questions regarding noise annoyance, although one used a 5-point scale and the other a 4-point scale. We used geographic information systems (GIS) to assess the average road and railway noise (LAeq,24h) at the participants' residential address. Logistic regression was used to calculate odds ratios for annoyance in relation to noise exposure. Results Annoyance at least once a week due to road traffic noise was significantly more prevalent in the survey investigating environment and health compared to the public health survey at levels > 45 dB(A), but not at lower exposure levels. However no differences in annoyance were found when comparing the extreme alternatives "never" and "every day". In the study investigating environment and health, "Noise sensitive" persons were more likely to readily respond to the survey and were more annoyed by road traffic noise compared to the other participants in that survey. Conclusions The differences in annoyance reporting between the two surveys were mainly due to different scales, suggesting that extreme alternatives are to prefer before

  5. The potential for chromium to affect the fertilization process of Chinook salmon (Oncorhynchus tshawytscha) in the Hanford Reach of the Columbia River, Washington, USA

    USGS Publications Warehouse

    Farag, A.M.; Harper, D.D.; Cleveland, L.; Brumbaugh, W.G.; Little, E.E.

    2006-01-01

    The Hanford Nuclear Reservation in south central Washington was claimed by the federal government as a site for the production of plutonium. During the course of production and operation of the facilities at Hanford, radionuclides and chromium were discharged directly into the river and also contaminated the groundwater. This study was designed to assess the effects of chromium (Cr) on Chinook salmon (Oncorhynchus tshawytscha) fertilization under exposure conditions similar to those of the Hanford Reach of the Columbia River. Chinook salmon gametes were exposed to aqueous Cr concentrations ranging from 0 to 266 ??g Cr l-1. The current ambient water-quality criteria (AWQC) established for the protection of aquatic life (United States Environmental Protection Agency [USEPA] 1986) is 11 ??g Cr l-1. Cr has been measured in pore water from bottom sediments of the Columbia River at concentrations >600 ??g Cr l-1. Under exposure conditions designed to closely mimic events that occur in the river, the fertilization of Chinook salmon eggs was not affected by concentrations of Cr ranging from 11 to 266 ??g Cr l-1. Data suggest that the instantaneous nature of fertilization likely limits the potential effects of Cr on fertilization success. As a result, the current AWQC of 11 ??g Cr l-1 is most likely protective of Chinook salmon fertilization. ?? 2006 Springer Science+Business Media, Inc.

  6. Introduced species and abiotic factors affect longitudinal variation in small fish assemblages in the Wind River watershed, Wyoming

    USGS Publications Warehouse

    Lionberger, P.S.; Hubert, W.A.

    2007-01-01

    We assessed longitudinal variation in small fish assemblages in the Wind River watershed upstream from Boysen Reservoir, Wyoming and into the reservoir. Twenty-six species were found in the study area, and 12 of the species were believed to have been introduced since settlement by Europeans. Additions and losses of fish species occurred with downstream progression, especially the addition of introduced species. Introduced species increased from 25% of the total number of species in the upper-most river segment (31.5-35.3 km upstream from the reservoir), to 46% in the river segment immediately upstream from the reservoir, to 48% in the reservoir. The most abundant species in the riverine portion of the watershed was the introduced sand shiner (Notropis stramineus). The results suggest that cyprinid species introduced to the upstream watershed and Boysen Reservoir are influencing small fish assemblages upstream from the reservoir and may be impacting native fishes, particularly native cyprinids.

  7. The Damping of Large Sediment Input Signals due to Attrition, Channel Morphologic Change, and Storage: the Fly River Watershed, Papua New Guinea

    NASA Astrophysics Data System (ADS)

    Dietrich, W. E.; Cui, Y.; Parker, G.; Moi, A.

    2001-12-01

    A key goal in watershed-scale sediment routing research is the quantification of the mechanisms that control the downstream dispersion of uplands sediment pulses. The release of over a billion tonnes of sediment at a mine site into a headwater tributary of the Fly River in Papua New Guinea during the past 15 years has created an extraordinary opportunity to document how the downstream fluvial system responds to increased load and to develop and test sediment routing models for predicting this response along a 700 km canyon river to lowland floodplain system. Pre-mining, the receiving tributary, the Ok Tedi river (which drains mountains reaching elevations of nearly 4000m), cascaded down a rapidly declining slope from bouldery canyon bound reaches through vegetated island bars reaches, breaking out onto a widening foothills plain where it abruptly decreased in slope and transformed to a downstream fining sand bedded meandering channel bordered by floodplains up to 14 km in width. Tailings of sand and silt constituted about one-third of the mine related load, with the rest of the sediment being a rocky waste and landslide materials. Three distinct depositional zones developed: a prograding debris fan which gave way to a downstream tapering wedge of braided gravel , which in turn abruptly shifted to a sand bedded reach, forming a separate downstream tapering wedge of aggradation. The debris flow reach caused massive channel incision and hillslope erosion upslope of the fan; aggradation in the gravel reach caused bed surface fining, considerable channel widening and elimination of vegetated island bars; and the aggradation in the sand bedded reach induced chronic flooding (which led to forest dieoff), accelerated channel migration (due to bar growth), levee growth, plugging of tie channels and massive infusion of sediment onto the floodplain. The largest aggradational response in the system was just below the mine and just downstream of the gravel-sand transition. For

  8. Conditions and processes affecting sand resources at archeological sites in the Colorado River corridor below Glen Canyon Dam, Arizona

    USGS Publications Warehouse

    East, Amy E.; Collins, Brian D.; Sankey, Joel B.; Corbett, Skye C.; Fairley, Helen C.; Caster, Joshua

    2016-05-17

    We conclude that most of the river-corridor archeological sites are at elevated risk of net erosion under present dam operations. In the present flow regime, controlled floods do not simulate the magnitude or frequency of natural floods, and are not large enough to deposit sand at elevations that were flooded at annual to decadal inte

  9. Potential Factors Affecting Survival Differ by Run-Timing and Location: Linear Mixed-Effects Models of Pacific Salmonids (Oncorhynchus spp.) in the Klamath River, California

    PubMed Central

    Quiñones, Rebecca M.; Holyoak, Marcel; Johnson, Michael L.; Moyle, Peter B.

    2014-01-01

    Understanding factors influencing survival of Pacific salmonids (Oncorhynchus spp.) is essential to species conservation, because drivers of mortality can vary over multiple spatial and temporal scales. Although recent studies have evaluated the effects of climate, habitat quality, or resource management (e.g., hatchery operations) on salmonid recruitment and survival, a failure to look at multiple factors simultaneously leaves open questions about the relative importance of different factors. We analyzed the relationship between ten factors and survival (1980–2007) of four populations of salmonids with distinct life histories from two adjacent watersheds (Salmon and Scott rivers) in the Klamath River basin, California. The factors were ocean abundance, ocean harvest, hatchery releases, hatchery returns, Pacific Decadal Oscillation, North Pacific Gyre Oscillation, El Niño Southern Oscillation, snow depth, flow, and watershed disturbance. Permutation tests and linear mixed-effects models tested effects of factors on survival of each taxon. Potential factors affecting survival differed among taxa and between locations. Fall Chinook salmon O. tshawytscha survival trends appeared to be driven partially or entirely by hatchery practices. Trends in three taxa (Salmon River spring Chinook salmon, Scott River fall Chinook salmon; Salmon River summer steelhead trout O. mykiss) were also likely driven by factors subject to climatic forcing (ocean abundance, summer flow). Our findings underscore the importance of multiple factors in simultaneously driving population trends in widespread species such as anadromous salmonids. They also show that the suite of factors may differ among different taxa in the same location as well as among populations of the same taxa in different watersheds. In the Klamath basin, hatchery practices need to be reevaluated to protect wild salmonids. PMID:24866173

  10. Potential factors affecting survival differ by run-timing and location: linear mixed-effects models of Pacific salmonids (Oncorhynchus spp.) in the Klamath River, California.

    PubMed

    Quiñones, Rebecca M; Holyoak, Marcel; Johnson, Michael L; Moyle, Peter B

    2014-01-01

    Understanding factors influencing survival of Pacific salmonids (Oncorhynchus spp.) is essential to species conservation, because drivers of mortality can vary over multiple spatial and temporal scales. Although recent studies have evaluated the effects of climate, habitat quality, or resource management (e.g., hatchery operations) on salmonid recruitment and survival, a failure to look at multiple factors simultaneously leaves open questions about the relative importance of different factors. We analyzed the relationship between ten factors and survival (1980-2007) of four populations of salmonids with distinct life histories from two adjacent watersheds (Salmon and Scott rivers) in the Klamath River basin, California. The factors were ocean abundance, ocean harvest, hatchery releases, hatchery returns, Pacific Decadal Oscillation, North Pacific Gyre Oscillation, El Niño Southern Oscillation, snow depth, flow, and watershed disturbance. Permutation tests and linear mixed-effects models tested effects of factors on survival of each taxon. Potential factors affecting survival differed among taxa and between locations. Fall Chinook salmon O. tshawytscha survival trends appeared to be driven partially or entirely by hatchery practices. Trends in three taxa (Salmon River spring Chinook salmon, Scott River fall Chinook salmon; Salmon River summer steelhead trout O. mykiss) were also likely driven by factors subject to climatic forcing (ocean abundance, summer flow). Our findings underscore the importance of multiple factors in simultaneously driving population trends in widespread species such as anadromous salmonids. They also show that the suite of factors may differ among different taxa in the same location as well as among populations of the same taxa in different watersheds. In the Klamath basin, hatchery practices need to be reevaluated to protect wild salmonids. PMID:24866173

  11. The influence of controlled floods on fine sediment storage in debris fan-affected canyons of the Colorado River basin

    NASA Astrophysics Data System (ADS)

    Mueller, Erich R.; Grams, Paul E.; Schmidt, John C.; Hazel, Joseph E.; Alexander, Jason S.; Kaplinski, Matt

    2014-12-01

    Prior to the construction of large dams on the Green and Colorado Rivers, annual floods aggraded sandbars in lateral flow-recirculation eddies with fine sediment scoured from the bed and delivered from upstream. Flows greater than normal dam operations may be used to mimic this process in an attempt to increase time-averaged sandbar size. These controlled floods may rebuild sandbars, but sediment deficit conditions downstream from the dams restrict the frequency that controlled floods produce beneficial results. Here, we integrate complimentary, long-term monitoring data sets from the Colorado River in Marble and Grand Canyons downstream from Glen Canyon dam and the Green River in the Canyon of Lodore downstream from Flaming Gorge dam. Since the mid-1990s, several controlled floods have occurred in these canyon rivers. These controlled floods scour fine sediment from the bed and build sandbars in eddies, thus increasing channel relief. These changes are short-lived, however, as interflood dam operations erode sandbars within several months to years. Controlled flood response and interflood changes in bed elevation are more variable in Marble Canyon and Grand Canyon, likely reflecting more variable fine sediment supply and stronger transience in channel bed sediment storage. Despite these differences, neither system shows a trend in fine-sediment storage during the period in which controlled floods were monitored. These results demonstrate that controlled floods build eddy sandbars and increase channel relief for short interflood periods, and this response may be typical in other dam-influenced canyon rivers. The degree to which these features persist depends on the frequency of controlled floods, but careful consideration of sediment supply is necessary to avoid increasing the long-term sediment deficit.

  12. The influence of controlled floods on fine sediment storage in debris fan-affected canyons of the Colorado River basin

    USGS Publications Warehouse

    Mueller, Erich R.; Grams, Paul E.; Schmidt, John C.; Hazel, Joseph E.; Alexander, Jason S.; Kaplinski, Matt

    2014-01-01

    Prior to the construction of large dams on the Green and Colorado Rivers, annual floods aggraded sandbars in lateral flow-recirculation eddies with fine sediment scoured from the bed and delivered from upstream. Flows greater than normal dam operations may be used to mimic this process in an attempt to increase time-averaged sandbar size. These controlled floods may rebuild sandbars, but sediment deficit conditions downstream from the dams restrict the frequency that controlled floods produce beneficial results. Here, we integrate complimentary, long-term monitoring data sets from the Colorado River in Marble and Grand Canyons downstream from Glen Canyon dam and the Green River in the Canyon of Lodore downstream from Flaming Gorge dam. Since the mid-1990s, several controlled floods have occurred in these canyon rivers. These controlled floods scour fine sediment from the bed and build sandbars in eddies, thus increasing channel relief. These changes are short-lived, however, as interflood dam operations erode sandbars within several months to years. Controlled flood response and interflood changes in bed elevation are more variable in Marble Canyon and Grand Canyon, likely reflecting more variable fine sediment supply and stronger transience in channel bed sediment storage. Despite these differences, neither system shows a trend in fine-sediment storage during the period in which controlled floods were monitored. These results demonstrate that controlled floods build eddy sandbars and increase channel relief for short interflood periods, and this response may be typical in other dam-influenced canyon rivers. The degree to which these features persist depends on the frequency of controlled floods, but careful consideration of sediment supply is necessary to avoid increasing the long-term sediment deficit.

  13. Mercury bioaccumulation in fish in a region affected by historic gold mining; the South Yuba River, Deer Creek, and Bear River watersheds, California, 1999

    USGS Publications Warehouse

    May, Jason T.; Hothem, Roger L.; Alpers, Charles N.; Law, Matthew A.

    2000-01-01

    Mercury that was used historically for gold recovery in mining areas of the Sierra Nevada continues to enter local and downstream water bodies, including the Sacramento Delta and the San Francisco Bay of northern California. Methylmercury is of particular concern because it is the most prevalent form of mercury in fish and is a potent neurotoxin that bioaccumulates at successive trophic levels within food webs. In April 1999, the U.S. Geological Survey, in cooperation with several other agencies the Forest Service (U.S. Department of Agriculture), the Bureau of Land Management, the U.S. Environmental Protection Agency, the California State Water Resources Control Board, and the Nevada County Resource Conservation District began a pilot investigation to characterize the occurrence and distribution of mercury in water, sediment, and biota in the South Yuba River, Deer Creek, and Bear River watersheds of California. Biological samples consisted of semi-aquatic and aquatic insects, amphibians, bird eggs, and fish. Fish were collected from 5 reservoirs and 14 stream sites during August through October 1999 to assess the distribution of mercury in these watersheds. Fish that were collected from reservoirs included top trophic level predators (black basses, Micropterus spp.) intermediate trophic level predators [sunfish (blue gill, Lepomis macrochirus; green sunfish, Lepomis cyanellus; and black crappie, Poxomis nigromaculatus)] and benthic omnivores (channel catfish, Ictularus punctatus). At stream sites, the species collected were upper trophic level salmonids (brown trout, Salmo trutta) and upper-to-intermediate trophic level salmonids (rainbow trout, Oncorhynchus mykiss). Boneless and skinless fillet portions from 161 fish were analyzed for total mercury; 131 samples were individual fish, and the remaining 30 fish were combined into 10 composite samples of three fish each of the same species and size class. Mercury concentrations in samples of black basses

  14. Analyses of potential factors affecting survival of juvenile salmonids volitionally passing through turbines at McNary and John Day Dams, Columbia River

    USGS Publications Warehouse

    Beeman, John; Hansel, Hal; Perry, Russell; Hockersmith, Eric; Sandford, Ben

    2011-01-01

    This report describes analyses of data from radio- or acoustic-tagged juvenile salmonids passing through hydro-dam turbines to determine factors affecting fish survival. The data were collected during a series of studies designed to estimate passage and survival probabilities at McNary (2002-09) and John Day (2002-03) Dams on the Columbia River during controlled experiments of structures or operations at spillways. Relatively few tagged fish passed turbines in any single study, but sample sizes generally were adequate for our analyses when data were combined from studies using common methods over a series of years. We used information-theoretic methods to evaluate biological, operational, and group covariates by creating models fitting linear (all covariates) or curvilinear (operational covariates only) functions to the data. Biological covariates included tag burden, weight, and water temperature; operational covariates included spill percentage, total discharge, hydraulic head, and turbine unit discharge; and group covariates included year, treatment, and photoperiod. Several interactions between the variables also were considered. Support of covariates by the data was assessed by comparing the Akaike Information Criterion of competing models. The analyses were conducted because there was a lack of information about factors affecting survival of fish passing turbines volitionally and the data were available from past studies. The depth of acclimation, tag size relative to fish size (tag burden), turbine unit discharge, and area of entry into the turbine intake have been shown to affect turbine passage survival of juvenile salmonids in other studies. This study indicates that turbine passage survival of the study fish was primarily affected by biological covariates rather than operational covariates. A negative effect of tag burden was strongly supported in data from yearling Chinook salmon at John Day and McNary dams, but not for subyearling Chinook salmon or

  15. Data Assimilation of AIRS Water Vapor Profiles: Impact on Precipitation Forecasts for Atmospheric River Cases Affecting the Western of the United States

    NASA Technical Reports Server (NTRS)

    Blankenship, Clay; Zavodsky, Bradley; Jedlovec, Gary; Wick, Gary; Neiman, Paul

    2013-01-01

    Atmospheric rivers are transient, narrow regions in the atmosphere responsible for the transport of large amounts of water vapor. These phenomena can have a large impact on precipitation. In particular, they can be responsible for intense rain events on the western coast of North America during the winter season. This paper focuses on attempts to improve forecasts of heavy precipitation events in the Western US due to atmospheric rivers. Profiles of water vapor derived from from Atmospheric Infrared Sounder (AIRS) observations are combined with GFS forecasts by a three-dimensional variational data assimilation in the Gridpoint Statistical Interpolation (GSI). Weather Research and Forecasting (WRF) forecasts initialized from the combined field are compared to forecasts initialized from the GFS forecast only for 3 test cases in the winter of 2011. Results will be presented showing the impact of the AIRS profile data on water vapor and temperature fields, and on the resultant precipitation forecasts.

  16. QMRAcatch - faecal microbial quality of water resources in a river-floodplain area affected by urban sources and recreational visitors

    NASA Astrophysics Data System (ADS)

    Derx, Julia; Schijven, Jack; Sommer, Regina; Kirschner, Alexander; Farnleitner, Andreas H.; Blaschke, Alfred Paul

    2016-04-01

    QMRAcatch, a tool to simulate microbial water quality including infection risk assessment, was previously developed and successfully tested at a Danube river site (Schijven et al. 2015). In the tool concentrations of target faecal microorganisms and viruses (TMVs) are computed at a point of interest (PI) along the main river and the floodplain river at daily intervals for a one year period. Even though faecal microbial pathogen concentrations in water resources are usually below the sample limit of detection, this does not ensure, that the water quality complies with a certain required health based target. The aim of this study was therefore to improve the predictability of relevant human pathogenic viruses, i.e. enterovirus and norovirus, in the studied river/floodplain area. This was done by following an innovative calibration strategy based on human-associated microbial source tracking (MST) marker data which were determined following the HF183 TaqMan assay (Green et al. 2011). The MST marker is strongly associated with human faeces and communal sewage, occurring there in numbers by several magnitudes higher than for human enteric pathogens (Mayer et al 2015). The calibrated tool was then evaluated with measured enterovirus concentrations at the PI and in the floodplain river. In the simulation tool the discharges of 5 wastewater treatment plants (WWTPs) were considered with point discharges along a 200 km reach of the Danube river. The MST marker and target virus concentrations at the PI at a certain day were computed based on the concentrations of the previous day, plus the wastewater concentrations times the WWTP discharge divided by the river discharge. A ratio of the river width was also considered, over which the MST marker and virus particles have fully mixed with river water. In the tool, the excrements from recreational visitors frequenting the floodplain area every day were assumed to be homogeneously distributed in the area. A binomial distributed

  17. QMRAcatch - faecal microbial quality of water resources in a river-floodplain area affected by urban sources and recreational visitors

    NASA Astrophysics Data System (ADS)

    Derx, Julia; Schijven, Jack; Sommer, Regina; Kirschner, Alexander; Farnleitner, Andreas H.; Blaschke, Alfred Paul

    2016-04-01

    QMRAcatch, a tool to simulate microbial water quality including infection risk assessment, was previously developed and successfully tested at a Danube river site (Schijven et al. 2015). In the tool concentrations of target faecal microorganisms and viruses (TMVs) are computed at a point of interest (PI) along the main river and the floodplain river at daily intervals for a one year period. Even though faecal microbial pathogen concentrations in water resources are usually below the sample limit of detection, this does not ensure, that the water quality complies with a certain required health based target. The aim of this study was therefore to improve the predictability of relevant human pathogenic viruses, i.e. enterovirus and norovirus, in the studied river/floodplain area. This was done by following an innovative calibration strategy based on human-associated microbial source tracking (MST) marker data which were determined following the HF183 TaqMan assay (Green et al. 2011). The MST marker is strongly associated with human faeces and communal sewage, occurring there in numbers by several magnitudes higher than for human enteric pathogens (Mayer et al 2015). The calibrated tool was then evaluated with measured enterovirus concentrations at the PI and in the floodplain river. In the simulation tool the discharges of 5 wastewater treatment plants (WWTPs) were considered with point discharges along a 200 km reach of the Danube river. The MST marker and target virus concentrations at the PI at a certain day were computed based on the concentrations of the previous day, plus the wastewater concentrations times the WWTP discharge divided by the river discharge. A ratio of the river width was also considered, over which the MST marker and virus particles have fully mixed with river water. In the tool, the excrements from recreational visitors frequenting the floodplain area every day were assumed to be homogeneously distributed in the area. A binomial distributed

  18. Feeding habits and habitats preferences affecting mercury bioaccumulation in 37 subtropical fish species from Wujiang River, China.

    PubMed

    Li, Sixin; Zhou, Lianfeng; Wang, Hongjun; Liang, Youguang; Chang, Jianbo; Xiong, Meihua; Zhang, Yichao; Hu, Juxiang

    2009-02-01

    The present study is the first to report the total mercury concentration of 37 fish species collected from Wujiang River, which is the largest branch on the southern bank of Yangtze River, China and proposed for hydropower development. Total mercury concentrations varied among the 37 subtropical species examined. We found higher mercury concentrations in carnivorous species demonstrating greater mercury bioaccumulation in species with more predatory feeding habits. There is no significant difference between fish grouped by habitat preference and feeding habit. However, carnivorous species preferring benthic positions had higher total mercury concentrations than others suggesting that mercury accumulation is related to the interaction of feeding habit and habitat preference. In our study, fish that are bottom living and feed on other fish or aquatic animals are more likely at high risk of mercury exposure. Additional mercury contamination and future impoundment may raise mercury concentration in fish in the Wujiang causing concern for human health and ecological impacts.

  19. Conditions and processes affecting sand resources at archeological sites in the Colorado River corridor below Glen Canyon Dam, Arizona

    USGS Publications Warehouse

    East, Amy E.; Collins, Brian D.; Sankey, Joel B.; Corbett, Skye C.; Fairley, Helen C.; Caster, Joshua

    2016-05-17

    We conclude that most of the river-corridor archeological sites are at elevated risk of net erosion under present dam operations. In the present flow regime, controlled floods do not simulate the magnitude or frequency of natural floods, and are not large enough to deposit sand at elevations that were flooded at annual to decadal intervals in predam time. For archeological sites that depend upon river-derived sand, we infer elevated erosion risk owing to a combination of reduced sand supply (both fluvial and aeolian) through (1) the lower-than-natural flood magnitude, frequency, and sediment supply of the controlled-flooding protocol; (2) reduction of open, dry sand area available for wind redistribution under current normal (nonflood) dam operations, which do not include flows as low as natural seasonal low flows and do include substantial daily flow fluctuations; and (3) impeded aeolian sand entrainment and transport owing to increased riparian vegetation growth in the absence of larger, more-frequent floods. If dam operations were to increase the supply of sand available for windblown transport—for example, through larger floods, sediment augmentation, or increased fluvial sandbar exposure by low flows—and also decrease riparian vegetation, the prevalence of active aeolian sand could increase over time, and the propensity for unmitigated gully erosion could decrease. Although the evolution of river-corridor landscapes and archeological sites has been altered fundamentally by the lack of large, sediment-rich floods (flows on the order of 5,000 m3/s), some combination of sediment-rich flows above 1,270 m3/s, seasonal flows below 226 m3/s, and riparian-vegetation removal might increase the preservation potential for sand-dependent archeological resources in the Colorado River corridor.

  20. Reservoir stratification affects methylmercury levels in river water, plankton, and fish downstream from Balbina hydroelectric dam, Amazonas, Brazil.

    PubMed

    Kasper, Daniele; Forsberg, Bruce R; Amaral, João H F; Leitão, Rafael P; Py-Daniel, Sarah S; Bastos, Wanderley R; Malm, Olaf

    2014-01-21

    The river downstream from a dam can be more contaminated by mercury than the reservoir itself. However, it is not clear how far the contamination occurs downstream. We investigated the seasonal variation of methylmercury levels in the Balbina reservoir and how they correlated with the levels encountered downstream from the dam. Water, plankton, and fishes were collected upstream and at sites between 0.5 and 250 km downstream from the dam during four expeditions in 2011 and 2012. Variations in thermal stratification of the reservoir influenced the methylmercury levels in the reservoir and in the river downstream. Uniform depth distributions of methylmercury and oxygen encountered in the poorly stratified reservoir during the rainy season collections coincided with uniformly low methylmercury levels along the river downstream from the dam. During dry season collections, the reservoir was strongly stratified, and anoxic hypolimnion water with high methylmercury levels was exported downstream. Methylmercury levels declined gradually to 200 km downstream. In general, the methylmercury levels in plankton and fishes downstream from the dam were higher than those upstream. Higher methylmercury levels observed 200-250 km downstream from the dam during flooding season campaigns may reflect the greater inflow from tributaries and flooding of natural wetlands that occurred at this time.

  1. Factors Affecting the Reproduction, Recruitment, Habitat, and Population Dynamics of Pallid Sturgeon and Shovelnose Sturgeon in the Missouri River

    USGS Publications Warehouse

    Korschgen, Carl E.

    2007-01-01

    For more than a hundred years, human activities have modified the natural forces that control the Missouri River and its native fish fauna. While the ecological effects of regulation and channel engineering are understood in general, the current understanding is not sufficient to guide river restoration and management. The U.S. Geological Survey (USGS) is in the third year of a multiagency research effort to determine the ecological requirements for reproduction and survival of the endangered pallid sturgeon (Scaphirhynchus albus) and shovelnose sturgeon (Scaphirhynchus platorhynchus) in the Missouri River. The multidisciplinary research strategy includes components of behavior, physiology, habitat use, habitat availability, and population modeling of all life stages. Shovelnose sturgeon are used to design the strategy because they are closely related to the pallid sturgeon and are often used as a surrogate species to develop new research tools or to examine the effects of management actions or environmental variables on sturgeon biology and habitat use. During fiscal years 2005 and 2006, the U.S. Army Corps of Engineers (USACE) provided funds to USGS for tasks associated with the Comprehensive Sturgeon Research Program (CSRP) and for tasks associated with evaluation of the Sturgeon Response to Flow Modifications (SRFM). Because work activities of CSRP and SRFM are so integrated, we are providing information on activities that have been consolidated at the task level. These task activities represent chapters in this report.

  2. Land degradation due to erosion in public perception. Case study: Secaşul Mare river basin settlements (Transylvanian Depression, Romania).

    PubMed

    Costea, Marioara; Tăuşan, Ioan

    2016-04-01

    According to the International Decade for Natural Disaster Reduction (IDNDR 1990-1999), the risk indicates potential losses due to particular natural phenomenon, and these could be reduced by improving of prevention and education. People perceive these losses differently depending on phenomenon occurrence, severity, and impact in time. Starting from this idea, this research presents public perception on land degradation through erosion in a small area from the central part of Romania (south-west of Transylvanian Depression). The research was based on a questionnaire consisting of 16 questions. The items were structured by issues: awareness assessment regarding hazard and risk phenomena, assessment of type of property and land use, assessment of knowledge and information on the possible production of negative effects by natural phenomena, and evaluation of land owners' attitudes towards the occurrence of erosion on their land. Results reveal that the public perception on erosion is weak. This process is perceived as insignificant due to lack of phenomenon knowledge and especially because of scarcity preoccupation in land's quality monitoring. Even though the owned lands are affected by erosion forms, the owners are not aware of the phenomenon that generates them. Material damages caused by erosion, loss of soil quality, and land fertility decrease are less perceived because the economic losses fill only at long term. This perception leads to underestimating erosion risk compared to other natural phenomena and to a passive attitude towards this particular phenomenon.

  3. Land degradation due to erosion in public perception. Case study: Secaşul Mare river basin settlements (Transylvanian Depression, Romania).

    PubMed

    Costea, Marioara; Tăuşan, Ioan

    2016-04-01

    According to the International Decade for Natural Disaster Reduction (IDNDR 1990-1999), the risk indicates potential losses due to particular natural phenomenon, and these could be reduced by improving of prevention and education. People perceive these losses differently depending on phenomenon occurrence, severity, and impact in time. Starting from this idea, this research presents public perception on land degradation through erosion in a small area from the central part of Romania (south-west of Transylvanian Depression). The research was based on a questionnaire consisting of 16 questions. The items were structured by issues: awareness assessment regarding hazard and risk phenomena, assessment of type of property and land use, assessment of knowledge and information on the possible production of negative effects by natural phenomena, and evaluation of land owners' attitudes towards the occurrence of erosion on their land. Results reveal that the public perception on erosion is weak. This process is perceived as insignificant due to lack of phenomenon knowledge and especially because of scarcity preoccupation in land's quality monitoring. Even though the owned lands are affected by erosion forms, the owners are not aware of the phenomenon that generates them. Material damages caused by erosion, loss of soil quality, and land fertility decrease are less perceived because the economic losses fill only at long term. This perception leads to underestimating erosion risk compared to other natural phenomena and to a passive attitude towards this particular phenomenon. PMID:26960766

  4. Intense secondary aerosol formation due to strong atmospheric photochemical reactions in summer: observations at a rural site in eastern Yangtze River Delta of China.

    PubMed

    Wang, Dongfang; Zhou, Bin; Fu, Qingyan; Zhao, Qianbiao; Zhang, Qi; Chen, Jianmin; Yang, Xin; Duan, Yusen; Li, Juan

    2016-11-15

    High pollution episodes of PM2.5 and O3 were frequently observed at a rural site (N31.0935º, E120.978°) in eastern Yangtze River Delta (YRD) in summer. To study the impacts of photochemical reactions on secondary aerosol formation in this region, we performed real-time measurements of the mass concentration and composition of PM2.5, particle size distribution (13.6~736.5 nm), concentrations of gas pollutants including O3, SO2, NO2, CO, non-methane hydrocarbons (NMHC)), and nitrate radical in 2013. During the sampling period, the average concentration of PM2.5 was 76.1 (± 16.5) μg/m(3), in which secondary aerosol species including sulfate, nitrate, ammonium, and secondary organic aerosol (SOA) accounted for ~ 62%. Gas-phase oxidation of SO2 was mainly responsible for a fast increase of sulfate (at 1.70 μg/m(3)/h) in the morning. Photochemical production of nitric acid was intense during daytime, but particulate nitrate concentration was low in the afternoon due to high temperature. At night, nitrate was mainly formed through the hydrolysis of NO3 and/or N2O5. The correlations among NMHC, Ox (= O3 + NO2), and SOA suggested that a combination of high emission of hydrocarbons and active photochemical reactions led to the rapid formation of SOA. In addition, several new particle formation and fast growth events were observed despite high ambient aerosol loading. Since the onset of new particle events was accompanied by a rapid increase of H2SO4 and SOA, enhanced formation of sulfate and SOA driven by photochemical oxidation likely promoted the formation and growth of new particles. Together, our results demonstrated that strong atmospheric photochemical reactions enhanced secondary aerosols formation and led to the synchronous occurrence of high concentrations of PM2.5 and O3 in a regional scale. These findings are important for better understanding the air pollution in summer in YRD. PMID:27418517

  5. Fragmentation and thermal risks from climate change interact to affect persistence of native trout in the Colorado River basin.

    PubMed

    Roberts, James J; Fausch, Kurt D; Peterson, Douglas P; Hooten, Mevin B

    2013-05-01

    Impending changes in climate will interact with other stressors to threaten aquatic ecosystems and their biota. Native Colorado River cutthroat trout (CRCT; Oncorhynchus clarkii pleuriticus) are now relegated to 309 isolated high-elevation (>1700 m) headwater stream fragments in the Upper Colorado River Basin, owing to past nonnative trout invasions and habitat loss. Predicted changes in climate (i.e., temperature and precipitation) and resulting changes in stochastic physical disturbances (i.e., wildfire, debris flow, and channel drying and freezing) could further threaten the remaining CRCT populations. We developed an empirical model to predict stream temperatures at the fragment scale from downscaled climate projections along with geomorphic and landscape variables. We coupled these spatially explicit predictions of stream temperature with a Bayesian Network (BN) model that integrates stochastic risks from fragmentation to project persistence of CRCT populations across the upper Colorado River basin to 2040 and 2080. Overall, none of the populations are at risk from acute mortality resulting from high temperatures during the warmest summer period. In contrast, only 37% of populations have a ≥90% chance of persistence for 70 years (similar to the typical benchmark for conservation), primarily owing to fragmentation. Populations in short stream fragments <7 km long, and those at the lowest elevations, are at the highest risk of extirpation. Therefore, interactions of stochastic disturbances with fragmentation are projected to be greater threats than warming for CRCT populations. The reason for this paradox is that past nonnative trout invasions and habitat loss have restricted most CRCT populations to high-elevation stream fragments that are buffered from the potential consequences of warming, but at risk of extirpation from stochastic events. The greatest conservation need is for management to increase fragment lengths to forestall these risks.

  6. Fragmentation and thermal risks from climate change interact to affect persistence of native trout in the Colorado River basin

    USGS Publications Warehouse

    Roberts, James J.; Fausch, Kurt D.; Peterson, Douglas P.; Hooten, Mevin B.

    2013-01-01

    Impending changes in climate will interact with other stressors to threaten aquatic ecosystems and their biota. Native Colorado River cutthroat trout (CRCT; Oncorhynchus clarkii pleuriticus) are now relegated to 309 isolated high-elevation (>1700 m) headwater stream fragments in the Upper Colorado River Basin, owing to past nonnative trout invasions and habitat loss. Predicted changes in climate (i.e., temperature and precipitation) and resulting changes in stochastic physical disturbances (i.e., wildfire, debris flow, and channel drying and freezing) could further threaten the remaining CRCT populations. We developed an empirical model to predict stream temperatures at the fragment scale from downscaled climate projections along with geomorphic and landscape variables. We coupled these spatially explicit predictions of stream temperature with a Bayesian Network (BN) model that integrates stochastic risks from fragmentation to project persistence of CRCT populations across the upper Colorado River basin to 2040 and 2080. Overall, none of the populations are at risk from acute mortality resulting from high temperatures during the warmest summer period. In contrast, only 37% of populations have a greater than or equal to 90% chance of persistence for 70 years (similar to the typical benchmark for conservation), primarily owing to fragmentation. Populations in short stream fragments <7 km long, and those at the lowest elevations, are at the highest risk of extirpation. Therefore, interactions of stochastic disturbances with fragmentation are projected to be greater threats than warming for CRCT populations. The reason for this paradox is that past nonnative trout invasions and habitat loss have restricted most CRCT populations to high-elevation stream fragments that are buffered from the potential consequences of warming, but at risk of extirpation from stochastic events. The greatest conservation need is for management to increase fragment lengths to forestall these

  7. Factors affecting food chain transfer of mercury in the vicinity of the Nyanza site, Sudbury River, Massachusetts

    USGS Publications Warehouse

    Haines, T.A.; May, T.W.; Finlayson, R.T.; Mierzykowski, S.E.

    2003-01-01

    The influence of the Nyanza Chemical Waste Dump Superfund Site on the Sudbury River, Massachusetts, was assessed by analysis of sediment, fish prey organisms, and predator fish from four locations in the river system. Whitehall Reservoir is an impoundment upstream of the site, and Reservoir #2 is an impoundment downstream of the site. Cedar Street is a flowing reach upstream of the site, and Sherman Bridge is a flowing reach downstream of the site. Collections of material for analysis were made three times, in May, July, and October. Sediment was analyzed for acid-volatile sulfide (AVS), simultaneously-extracted (SEM) metals (As, Cd, Cr, Hg, Pb, Sb, Zn), and total recoverable Hg. The dominant predatory fish species collected at all sites, largemouth bass (Micropterus salmoides), was analyzed for the same suite of metals as sediment. Analysis of stomach contents of bass identified small fish (yellow perch Perca flavescens, bluegill Lepomis macrochirus, and pumpkinseed Lepomis gibbosus), crayfish, and dragonfly larvae as the dominant prey organisms. Samples of the prey were collected from the same locations and at the same times as predator fish, and were analyzed for total and methyl mercury. Results of AVS and SEM analyses indicated that sediments were not toxic to aquatic invertebrates at any site. The SEM concentrations of As, Cd, and Cr were significantly higher at Reservoir #2 than at the reference sites, and SEM As and Cd were significantly higher at Sherman Bridge than at Cedar St. Sediment total Hg was elevated only at Reservoir #2. Hg was higher at site-influenced locations in all fish species except brown bullhead (Ameiurus nebulosus). Cd was higher in bluegill, black crappie (Pomoxis nigromaculatus), and brown bullhead, and Cr was higher in largemouth bass fillet samples but not in whole-body samples. There were no seasonal differences in sediment or prey organism metals, but some metals in some fish species did vary over time in an inconsistent manner

  8. Hydrological modeling of a watershed affected by acid mine drainage (Odiel River, SW Spain). Assessment of the pollutant contributing areas

    NASA Astrophysics Data System (ADS)

    Galván, L.; Olías, M.; Cánovas, C. R.; Sarmiento, A. M.; Nieto, J. M.

    2016-09-01

    The Odiel watershed drains materials belonging to the Iberian Pyrite Belt, where significant massive sulfide deposits have been mined historically. As a result, a huge amount of sulfide-rich wastes are deposited in the watershed, which suffer from oxidation, releasing acidic lixiviates with high sulfate and metal concentrations. In order to reliably estimate the metal loadings along the watershed a complete series of discharge and hydrochemical data are essential. A hydrological model was performed with SWAT (Soil and Water Assessment Tool) to solve the scarcity of gauge stations along the watershed. The model was calibrated and validated from daily discharge data (from 1980 to 2010) at the outlet of the watershed, river inputs into an existent reservoir, and a flow gauge station close to the northern area of the watershed. Discharge data obtained from the hydrological model, together with analytical data, allowed the estimation of the dissolved pollutant load delivered annually by the Odiel River (e.g. 9140 t of Al, 2760 t of Zn). The pollutant load is influenced strongly by the rainfall regime, and can even double during extremely rainy years. Around 50% of total pollution comes from the Riotinto Mining District, so the treatment of Riotinto lixiviates reaching the Odiel watershed would reduce the AMD (Acid Mine Drainages) in a remarkable way, improving the water quality downstream, especially in the reservoir of Alcolea, currently under construction. The information obtained in this study will allow the optimization of remediation efforts in the watershed, in order to improve its water quality.

  9. Impact of AIRS Thermodynamic Profiles on Precipitation Forecasts for Atmospheric River Cases Affecting the Western United States

    NASA Technical Reports Server (NTRS)

    Zavodsky, Bradley T.; Jedlovec, Gary J.; Blakenship, Clay B.; Wick, Gary A.; Neiman, Paul J.

    2013-01-01

    This project is a collaborative activity between the NASA Short-term Prediction Research and Transition (SPoRT) Center and the NOAA Hydrometeorology Testbed (HMT) to evaluate a SPoRT Advanced Infrared Sounding Radiometer (AIRS: Aumann et al. 2003) enhanced moisture analysis product. We test the impact of assimilating AIRS temperature and humidity profiles above clouds and in partly cloudy regions, using the three-dimensional variational Gridpoint Statistical Interpolation (GSI) data assimilation (DA) system (Developmental Testbed Center 2012) to produce a new analysis. Forecasts of the Weather Research and Forecasting (WRF) model initialized from the new analysis are compared to control forecasts without the additional AIRS data. We focus on some cases where atmospheric rivers caused heavy precipitation on the US West Coast. We verify the forecasts by comparison with dropsondes and the Cooperative Institute for Research in the Atmosphere (CIRA) Blended Total Precipitable Water product.

  10. Does water level affect benthic macro-invertebrates of a marginal lake in a tropical river-reservoir transition zone?

    PubMed

    Zerlin, R A; Henry, R

    2014-05-01

    Benthic macro-invertebrates are important components of freshwater ecosystems which are involved in ecological processes such as energy transfer between detritus and consumers and organic matter recycling. The aim of this work was to investigate the variation in organism richness, diversity and density of benthic fauna during the annual cycle in Camargo Lake, a lake marginal to Paranapanema River, southeast Brazil. The correlation of environmental factors with community attributes of the macro-benthic fauna was assessed. Since Camargo Lake is connected to the river, we tested the hypothesis that water level variation is the main regulating factor of environmental variables and of the composition and abundance of benthic macro-invertebrates. The results indicated that lake depth varied with rainfall, being the highest at the end of the rising water period and the lowest at the beginning of this period. The sediment granulometry was more heterogeneous at the bottom of the lake by the end of the high water period. The benthic macro-invertebrate fauna was composed by 15 taxa. The Diptera order was represented by seven taxa and had greater richness in relation to other taxa. This group was responsible for 60% of the total abundance of organisms, followed by Ephemeroptera (22%) and Anellida (16%). Significant differences were observed over time in total richness and, in density of Narapa bonettoi, Chaoborus, Ablabesmyia gr. annulata, Chironomus gigas, Larsia fittkau, and Procladius sp. 2. Total taxa richness correlated negatively with water pH, transparency, conductivity, and bottom water oxygen. Higher positive correlations were found between the densities of some taxa and bottom water oxygen, conductivity and very fine sand, silt + clay of sediment, while negative correlations were recorded with organic matter, and fine, medium and coarse sand, bottom water temperature, mean temperature and rainfall. The significant temporal difference in water level was associated

  11. Generalized results of individualized exposure doses reconstruction for the subjects of Ukrainian State Register of persons, affected due to Chernobyl accident.

    PubMed

    Likhtarov, I A; Kovgan, L M; Masiuk, S V; Ivanova, O M; Chepurny, M I; Boyko, Z N; Gerasymenko, V B; Tereshchenko, S A; Kravchenko, I G; Kortushin, G I; Marcenjyk, O D; Gubina, I G

    2015-12-01

    Since 2007, the department of dosimetry of NRCRM has been working for to supply the Ukrainian State Register (SRU) of persons affected due to Chernobyl accident by exposure doses estimations. As of now, the individualization of doses has been performed for nine raions located in Kyiv, Zhytomyr, Rivne and Chernihiv oblasts. The structure of raion-specific models used for the reconstruction of individualized doses was described in detail in the previous 19-th issue of this journal (2014). The choice conditions for persons from the SRU using which for each raion there was formed a contingent of persons for whom the dose could be reconstructed. During the period of 2007-2015, the individualized dose was reconstructed for 244226 persons in 9 raions, representing ~ 58% of all registered in the SRU inhabitants of the raions. The calculation results were transferred to the SRU in formats adapted to the common database structure of the SRU. For each person who satisfied the conditions of selection there were estimated: (1) possible absorbed internal exposure dose of the thyroid by radioiodine in 1986 (assuming that the person in 1986 lived in the same village and was enlisted in the SRU); (2) annual doses of external, internal and total exposure of the whole body for a period of observation in the SRU; (3) total exposure dose of whole body accumulated during the period of observation in the SRU; (4) the total cumulative dose of feasible exposure during the period since 1986 till the decision to be registered in the SRU. There are presented the generalized results of the SRU subjects distribution for different raions in dependence on intervals of doses accumulated at different periods after the accident. The raion matrix tables show the dynamics of accumulation of doses by the SRU subjects both for their stay on the account and for the period of their possible residence registration in the settlement since 1986. The directions for further research to be implemented for

  12. Water quality changes in floodplain lakes due to the Amazon River flood pulse: Lago Grande de Curuaí (Pará).

    PubMed

    Affonso, A G; Barbosa, C; Novo, E M L M

    2011-08-01

    Assurance of water quality for human consumption is essential for public health policies. In the Amazon floodplain, the seasonal water level variation causes periodic flooding of marginal areas that are usually used for settlements, agriculture and livestock. Therefore, the exchange of materials between the terrestrial and aquatic ecosystem affects the proportion of suspended and dissolved components in water and its physical-chemical characteristics, and consequently the quality of the water used by local people. Following this approach, the aim of this study is to evaluate changes in water quality in Lago Grande de Curuaí floodplain, Óbidos, Pará in response to the flood pulse, during one hydrological year from 2003 to 2004, based on water use classes (according to National Water Agency 357/2005 resolution) using chlorophyll-a and dissolved oxygen concentration as parameters and the eutrophication index. Ordinary kriging was applied to interpolate chlorophyll-a and dissolved oxygen and to predict values at non sampled locations. Each location was then classified according to water use acceptable parameters and to Carlson Trophic State Index modified by Toledo to map lake water classes and trophic status. The result showed that Lago Grande de Curuaí floodplain is a supereutrophic system, with levels of dissolved oxygen and chlorophyll-a not suitable for human supply during the receding water phase. These areas are located near the riverine communities, which can cause health problems due to the presence of potentially toxic algae. Therefore, monitoring water quality in Amazon lakes is essential to ensure the availability has appropriate quality for human and animal supplies.

  13. Water quality, sediment, and soil characteristics near Fargo-Moorhead urban areas as affected by major flooding of the Red River of the North.

    PubMed

    Guy, A C; Desutter, T M; Casey, F X M; Kolka, R; Hakk, H

    2012-01-01

    Spring flooding of the Red River of the North (RR) is common, but little information exits on how these flood events affect water and overbank sediment quality within an urban area. With the threat of the spring 2009 flood in the RR predicted to be the largest in recorded history and the concerns about the flooding of farmsteads, outbuildings, garages, and basements, the objectives of this study, which focused on Fargo, ND, and Moorhead, MN, were to assess floodwater quality and to determine the quantity and quality of overbank sediment deposited after floodwaters recede and the quality of soil underlying sediment deposits. 17β-Estradiol was detected in 9 of 24 water samples, with an average concentration of 0.61 ng L. Diesel-range organics were detected in 8 of 24 samples, with an average concentration of 80.0 μg L. The deposition of sediment across locations and transects ranged from 2 to 10 kg m, and the greatest mass deposition of chemicals was closest to the river channel. No gasoline-range organics were detected, but diesel-range organics were detected in 26 of the 27 overbank sediment samples (maximum concentration, 49.2 mg kg). All trace elements detected in the overbank sediments were within ranges for noncontaminated sites. Although flooding has economic, social, and environmental impacts, based on the results of this study, it does not appear that flooding in the RR in F-M led to decreased quality of water, sediment, or soil compared with normal river flows or resident soil.

  14. Dynamics and sources of reduced sulfur, humic substances and dissolved organic carbon in a temperate river system affected by agricultural practices.

    PubMed

    Marie, Lauriane; Pernet-Coudrier, Benoît; Waeles, Matthieu; Gabon, Marine; Riso, Ricardo

    2015-12-15

    Although reduced organic sulfur substances (RSS) as well as humic substances (HS) are widely suspected to play a role in, for example, metal speciation or used as a model of dissolved organic carbon (DOC) in laboratory studies, reports of their quantification in natural waters are scarce. We have examined the dynamics and sources of reduced sulfur, HS and DOC over an annual cycle in a river system affected by agricultural practices. The new differential pulse cathodic stripping voltammetry was successfully applied to measure glutathione-like compounds (GSHs), thioacetamide-like compounds (TAs) and the liquid chromatography coupled to organic detector to analyze HS and DOC at high frequency in the Penzé River (NW France). The streamflow-concentration patterns, principal components analysis and flux analysis allowed discrimination of the source of each organic compound type. Surprisingly, the two RSS and HS detected in all samples, displayed different behavior. As previously shown, manuring practice is the main source of DOC and HS in this watershed where agricultural activity is predominant. The HS were then transferred to the river systems via runoff, particularly during the spring and autumn floods, which are responsible of >60% of the annual flux. TAs had a clear groundwater source and may be formed underground, whereas GSHs displayed two sources: one aquagenic in spring and summer probably linked to the primary productivity and a second, which may be related to bacterial degradation. High sampling frequency allowed a more accurate assessment of the flux values which were 280 tC y(-1) for DOC representing 20 kg C ha(-1) y(-1). HS, TAs and GSHs fluxes represented 60, 13, and 4% of the total annual DOC export, respectively.

  15. Dynamics and sources of reduced sulfur, humic substances and dissolved organic carbon in a temperate river system affected by agricultural practices.

    PubMed

    Marie, Lauriane; Pernet-Coudrier, Benoît; Waeles, Matthieu; Gabon, Marine; Riso, Ricardo

    2015-12-15

    Although reduced organic sulfur substances (RSS) as well as humic substances (HS) are widely suspected to play a role in, for example, metal speciation or used as a model of dissolved organic carbon (DOC) in laboratory studies, reports of their quantification in natural waters are scarce. We have examined the dynamics and sources of reduced sulfur, HS and DOC over an annual cycle in a river system affected by agricultural practices. The new differential pulse cathodic stripping voltammetry was successfully applied to measure glutathione-like compounds (GSHs), thioacetamide-like compounds (TAs) and the liquid chromatography coupled to organic detector to analyze HS and DOC at high frequency in the Penzé River (NW France). The streamflow-concentration patterns, principal components analysis and flux analysis allowed discrimination of the source of each organic compound type. Surprisingly, the two RSS and HS detected in all samples, displayed different behavior. As previously shown, manuring practice is the main source of DOC and HS in this watershed where agricultural activity is predominant. The HS were then transferred to the river systems via runoff, particularly during the spring and autumn floods, which are responsible of >60% of the annual flux. TAs had a clear groundwater source and may be formed underground, whereas GSHs displayed two sources: one aquagenic in spring and summer probably linked to the primary productivity and a second, which may be related to bacterial degradation. High sampling frequency allowed a more accurate assessment of the flux values which were 280 tC y(-1) for DOC representing 20 kg C ha(-1) y(-1). HS, TAs and GSHs fluxes represented 60, 13, and 4% of the total annual DOC export, respectively. PMID:26278374

  16. Sediment Budgeting in Dam-Affected Rivers: Assessing the Influence of Damming, Tributaries, and Alluvial Valley Sediment Storage on Sediment Regimes

    NASA Astrophysics Data System (ADS)

    Wilcox, A. C.; Dekker, F. J.; Riebe, C. S.

    2014-12-01

    Although sediment supply is recognized as a fundamental driver of fluvial processes, measuring how dams affect sediment regimes and incorporating such knowledge into management strategies remains challenging. To determine the influences of damming, tributary supply, and valley morphology and sediment storage on downstream sediment supply in a dryland river, the Bill Williams River (BWR) in western Arizona, we measured basin erosion rates using cosmogenic nuclide analysis of beryllium-10 (10Be) at sites upstream and downstream of a dam along the BWR, as well as from tributaries downstream of the dam. Riverbed sediment mixing calculations were used to test if the dam, which blocks sediment supply from the upper 85% of the basin's drainage area, increases the proportion of tributary sediment to residual upstream sediment in mainstem samples downstream of the dam. Erosion rates in the BWR watershed are more than twice as large in the upper catchment (136 t km-2 yr-1) than in tributaries downstream of Alamo Dam (61 t km-2 yr-1). Tributaries downstream of the dam have little influence on mainstem sediment dynamics. The effect of the dam on reducing sediment supply is limited, however, because of the presence of large alluvial valleys along the mainstem BWR downstream of the dam that store substantial sediment and mitigate supply reductions from the upper watershed. These inferences, from our 10Be derived erosion rates and mixing calculations, are consistent with field observations of downstream changes in bed material size, which suggest that sediment-deficit conditions are restricted to a 10 km reach downstream of the dam, and limited reservoir bathymetry data. Many studies have suggested that tributary sediment inputs downstream of dams play a key role in mitigating dam-induced sediment deficits, but here we show that in a dryland river with ephemeral tributaries, sediment stored in alluvial valleys can also play a key role and in some cases trumps the role of

  17. Exposure of inshore corals to suspended sediments due to wave-resuspension and river plumes in the central Great Barrier Reef: A reappraisal

    NASA Astrophysics Data System (ADS)

    Orpin, Alan R.; Ridd, Peter V.

    2012-09-01

    Suspended sediment in the coastal zone is an important limiting factor for the growth and health of inshore coral reefs. The Great Barrier Reef (GBR) lagoon receives sediment from a number of tropical rivers and the physical and biological effects of riverine discharge and turbidity within the lagoon are of considerable scientific and public interest. Published data from two inshore regions of the GBR are reviewed herein to evaluate the relative influence of river plumes and wave resuspension on suspended sediment concentration (SSC) around coral communities over a range of timescales. Data from Cleveland Bay and from other sites near the mouth of the Tully River show that wave resuspension is the most dominant mechanism controlling SSC at inshore reefs. At many nearshore areas today fine-grained bed sediment is abundant, consistent with millennial-scale geological evidence of sediment dispersal prior to European settlement and catchment impacts. Flocculation, particle settling and dilution occurs within the river plume, and riverine sediment concentrations at reefs directly attributable to individual flood inputs is significantly reduced, suggesting that the plume component is a relatively small contribution to the total suspended sediment mass balance over inter-annual timescales. Resuspension events can generate higher ambient SSC than that measured in flood waters (e.g. Tully River). In addition, while visually spectacular, satellite and aerial images offer limited quantitative information of total sediment load carried by hypopycnal plumes, as many of these plumes may contain algal blooms but relatively low concentrations of suspended sediment (ca. <5 mg/l). Nonetheless, the cumulative effect of sediment-laden plumes may be a vector for other adsorbed contaminants of potential ecological concern, but coral smothering by hypopycnal plumes alone appears an unlikely impact particularly at inner- and middle-shelf reefs exposed to high wave energy and resuspension

  18. Factors that affect molecular weight distribution of Suwannee river fulvic acid as determined by electrospray ionization/mass spectrometry

    USGS Publications Warehouse

    Rostad, C.E.; Leenheer, J.A.

    2004-01-01

    Effects of methylation, molar response, multiple charging, solvents, and positive and negative ionization on molecular weight distributions of aquatic fulvic acid were investigated by electrospray ionization/mass spectrometry. After preliminary analysis by positive and negative modes, samples and mixtures of standards were derivatized by methylation to minimize ionization sites and reanalyzed.Positive ionization was less effective and produced more complex spectra than negative ionization. Ionization in methanol/water produced greater response than in acetonitrile/water. Molar response varied widely for the selected free acid standards when analyzed individually and in a mixture, but after methylation this range decreased. After methylation, the number average molecular weight of the Suwannee River fulvic acid remained the same while the weight average molecular weight decreased. These differences are probably indicative of disaggregation of large aggregated ions during methylation. Since the weight average molecular weight decreased, it is likely that aggregate formation in the fulvic acid was present prior to derivatization, rather than multiple charging in the mass spectra. ?? 2004 Elsevier B.V. All rights reserved.

  19. Seasonal and interannual variability of sea-air CO2 fluxes in the tropical Atlantic affected by the Amazon River plume

    NASA Astrophysics Data System (ADS)

    Ibánhez, J. Severino P.; Diverrès, Denis; Araujo, Moacyr; Lefèvre, Nathalie

    2015-10-01

    CO2 fugacities obtained from a merchant ship sailing from France to French Guyana were used to explore the seasonal and interannual variability of the sea-air CO2 exchange in the western tropical North Atlantic (TNA; 5-14°N, 41-52°W). Two distinct oceanic water masses were identified in the area associated to the main surface currents, i.e., the North Brazil Current (NBC) and the North Equatorial Current (NEC). The NBC was characterized by permanent CO2 oversaturation throughout the studied period, contrasting with the seasonal pattern identified in the NEC. The NBC retroflection was the main contributor to the North Equatorial Counter Current (NECC), thus spreading into the central TNA, the Amazon River plume, and the CO2-rich waters probably originated from the equatorial upwelling. Strong CO2 undersaturation was associated to the Amazon River plume. Total inorganic carbon drawdown due to biological activity was estimated to be 154 µmol kg-1 within the river plume. As a consequence, the studied area acted as a net sink of atmospheric CO2 (from -72.2 ± 10.2 mmol m-2 month-1 in February to 14.3 ± 4.5 mmol m-2 month-1 in May). This contrasted with the net CO2 efflux estimated by the main global sea-air CO2 flux climatologies. Interannual sea surface temperature changes in the TNA caused by large-scale climatic events could determine the direction and intensity of the sea-air CO2 fluxes in the NEC. Positive temperature anomalies observed in the TNA led to an almost permanent CO2 outgassing in the NEC in 2010.

  20. Factors affecting domestic water consumption in rural households upon access to improved water supply: insights from the Wei River Basin, China.

    PubMed

    Fan, Liangxin; Liu, Guobin; Wang, Fei; Geissen, Violette; Ritsema, Coen J

    2013-01-01

    Comprehensively understanding water consumption behavior is necessary to design efficient and effective water use strategies. Despite global efforts to identify the factors that affect domestic water consumption, those related to domestic water use in rural regions have not been sufficiently studied, particularly in villages that have gained access to improved water supply. To address this gap, we investigated 247 households in eight villages in the Wei River Basin where three types of improved water supply systems are implemented. Results show that domestic water consumption in liters per capita per day was significantly correlated with water supply pattern and vegetable garden area, and significantly negatively correlated with family size and age of household head. Traditional hygiene habits, use of water appliances, and preference for vegetable gardening remain dominant behaviors in the villages with access to improved water supply. Future studies on rural domestic water consumption should pay more attention to user lifestyles (water appliance usage habits, outdoor water use) and cultural backgrounds (age, education).

  1. Natural and anthropogenic factors affecting the structure of the benthic macroinvertebrate community in an effluent-dominated reach of the Santa Cruz River, AZ

    USGS Publications Warehouse

    Boyle, T.P.; Fraleigh, H.D.

    2003-01-01

    This study provides an assessment of the ecological conditions of a 46-km effluent-dominated stream section of the Santa Cruz River in the vicinity of the International Waste Water Treatment Plant, Nogales, AZ. We associated changes in the structure of the macroinvertebrate community to natural and anthropogenic chemical and physical variables using multivariate analysis. The analysis shows that biological criteria for effluent-dominated streams can be established using macroinvertebrate community attributes only with an understanding of the contribution of three classes of variables on the community structure: (1) low flow hydrological discharge as affected by groundwater withdrawals, treatment plant discharge, and subsurface geomorphology; (2) chemical composition of the treatment plant discharge and natural dilution; and (3) naturally produced floods resulting from seasonality of precipitation. ?? 2003 Elsevier Science Ltd. All rights reserved.

  2. [Distribution characteristics of dissolved oxygen and its affecting factors in the Pearl River Estuary during the summer of the extremely drought hydrological year 2011].

    PubMed

    Ye, Feng; Huang, Xiao-ping; Shi, Zhen; Liu, Qing-xi

    2013-05-01

    More and more attention has focused on assessing impacts of extreme hydrologic events on estuarine ecosystem under the background of climate change. Based on a summer cruise conducted in the Pearl River Estuary in 2011 (extreme drought event), we have investigated the spatial distribution of dissolved oxygen (DO) and its relationships to water column stability, nutrient concentrations, and organic matter; besides, the major reason which caused the oxygen depletion was discussed. Under the influence of the extreme drought event, low bottom water dissolved oxygen was apparent in regions characterized by great depths, with an oxygen minimum value of 1.38 mg x L(-1). Statistical analysis shows significant correlations among deltaDO, deltaT, deltaS and deltaPOC. A comparison was conducted to show the mechanisms of oxygen depletion during the summers of 1999, 2009 and 2011, respectively. The result indicates that prolonged residence time of water due to the extremely low discharge and the subsequently decomposition of organic substance are major factors causing the formation of hypoxia during the summer drought in 2011. Despite the changing nutrient and organic matter regime in the Pearl River Estuary, there was no apparent trend in the minimum values of DO over the past 2 decades.

  3. Soil freezing and thawing processes affected by the different landscapes in the middle reaches of Heihe River Basin, Gansu, China

    NASA Astrophysics Data System (ADS)

    Yi, Jun; Zhao, Ying; Shao, Ming'an; Zhang, Jianguo; Cui, Lele; Si, Bingcheng

    2014-11-01

    An understanding of soil freezing and thawing processes in seasonally frozen soil is important for many agricultural and environmental issues, especially under different landscapes in terms of land use and climate change. In this study, sandy soil behavior under soil freezing and thawing cycles were investigated under three typical landscapes (i.e., farmland, forest, and desert) in the middle reaches of the Heihe River Basin, Northwest China, from December 2011 to May 2012. Both Neutron Moisture Meter and Time Domain Reflectometry techniques were used to investigate the total soil water content (TSWC) and liquid soil water content (LSWC), respectively, and further based on to calculate soil ice content (SIC) and ice ratio (IR). The partition TSWC into LSWC and SIC at different depths is shown to be corresponded well with soil temperature, frost depth and groundwater dynamics, provided a vigorous basis for augmenting the limited data on soil water redistribution in seasonally frozen soils under natural conditions of different landscapes. The greatest freezing cycles were observed for the farmland, characterized with the deepest frost depths (106 cm), the highest IR (>0.9), and the largest upward heat fluxes (120 W m-2), followed by the forest, and then the desert. These differences were primarily attributed to landscape-dependent initial soil water content, soil surface cover and groundwater levels, with marginal effect being attributed to soil physical properties. Profiled water redistribution upon soil freezing and thawing was obviously observed in the moist forest, but neither in the wettest farmland or in the driest desert. The soil frozen processes had a beneficial effect on soil water conservation with reduced evaporation and seepage, and high water content maintained, which could be useful for plant germination in the following spring.

  4. Assessment of committed effective dose due to the ingestion of (210)Po and (210)Pb in consumed Lebanese fish affected by a phosphate fertilizer plant.

    PubMed

    Aoun, M; El Samad, O; Bou Khozam, R; Lobinski, R

    2015-02-01

    Ingestion of radionuclides through seafood intake is a one of the sources contributing to the internal effective dose in the human organism. In order to evaluate the internal exposure and potential risks due to (210)Po and (210)Pb associated with fish consumption, these radionuclides were measured in commonly consumed fish species from a clean area and an area subjected to the impact of a Lebanese phosphate fertilizer plant. The highest concentration of (210)Pb was 98.7 Bq/kg fresh weight while (210)Po activity concentrations varied from 3.6 Bq/kg to 140 Bq/kg. A supplementary radiation exposure was detected; the highest committed effective dose due to (210)Po and (210)Pb was found to be 1110 μSv/y and 450 μSv/y, respectively. Moreover, the average mortality and morbidity risks due to the fish consuming were estimated.

  5. Assessment of committed effective dose due to the ingestion of (210)Po and (210)Pb in consumed Lebanese fish affected by a phosphate fertilizer plant.

    PubMed

    Aoun, M; El Samad, O; Bou Khozam, R; Lobinski, R

    2015-02-01

    Ingestion of radionuclides through seafood intake is a one of the sources contributing to the internal effective dose in the human organism. In order to evaluate the internal exposure and potential risks due to (210)Po and (210)Pb associated with fish consumption, these radionuclides were measured in commonly consumed fish species from a clean area and an area subjected to the impact of a Lebanese phosphate fertilizer plant. The highest concentration of (210)Pb was 98.7 Bq/kg fresh weight while (210)Po activity concentrations varied from 3.6 Bq/kg to 140 Bq/kg. A supplementary radiation exposure was detected; the highest committed effective dose due to (210)Po and (210)Pb was found to be 1110 μSv/y and 450 μSv/y, respectively. Moreover, the average mortality and morbidity risks due to the fish consuming were estimated. PMID:25461512

  6. Assessing water source and channel type as factors affecting benthic macroinvertebrate and periphyton assemblages in the highly urbanized Santa Ana River Basin, California

    USGS Publications Warehouse

    Burton, C.A.; Brown, L.R.; Belitz, K.

    2005-01-01

    The Santa Ana River basin is the largest stream system in Southern California and includes a densely populated coastal area. Extensive urbanization has altered the geomorphology and hydrology of the streams, adversely affecting aquatic communities. We studied macroinvertebrate and periphyton assemblages in relation to two categorical features of the highly engineered hydrologic system-water source and channel type. Four water sources were identified-natural, urban-impacted groundwater, urban runoff, and treated wastewater. Three channel types were identified-natural, channelized with natural bottom, and concrete-lined. Nineteen sites, covering the range of these two categorical features, were sampled in summer 2000. To minimize the effects of different substrate types among sites, artificial substrates were used for assessing macroinvertebrate and periphyton assemblages. Physical and chemical variables and metrics calculated from macroinvertebrate and periphyton assemblage data were compared among water sources and channel types using analysis of variance and multiple comparison tests. Macroinvertebrate metrics exhibiting significant (P < 0.05) differences between water sources included taxa and Ephemeroptera-Plecoptera-Trichoptera richness, relative richness and abundance of nonchironomid dipterans, orthoclads, oligochaetes, and some functional-feeding groups such as parasites and shredders. Periphyton metrics showing significant differences between water sources included blue-green algae biovolume and relative abundance of nitrogen heterotrophic, eutrophic, motile, and pollution-sensitive diatoms. The relative abundance of trichopterans, tanytarsini chironomids, noninsects, and filter feeders, as well as the relative richness and abundance of diatoms, were significantly different between channel types. Most physical variables were related to channel type, whereas chemical variables and some physical variables (e.g., discharge, velocity, and channel width) were

  7. Characteristics of streams and aquifers and processes affecting the salinity of water in the upper Colorado River basin, Texas

    USGS Publications Warehouse

    Slade, R.M.; Buszka, P.M.

    1994-01-01

    The chemical characteristics of the saline water in streams and shallow aquifers in the study area were compared to characteristics of water that would result from the probable processes affecting the salinity of water, such as evapotranspiration, mineral dissolution, and mixing of water from streams and shallow-aquifer water with brines from deep aquifers. Dissolution of halite or mixing with deep-aquifer water was the most common cause of increased salinity in 48.0 percent of 77 water samples from shallow aquifers, as classified using salt-norm analysis; the second most common cause was the weathering and dissolution of sulfur-bearing minerals. Mixing with water from soil-mineral dissolution was classified as the principal source of chloride in 28.4 percent of 67 water samples from shallow aquifers with nitrate determinations. Trace-species/chloride ratios indicated that mixing with water from deep aquifers in rocks of the Pennsylvanian System was the principal source of chloride in 24.4 percent of 45 shallow-aquifer samples lacking nitrate determinations.

  8. Clay mineralogical evidence of a bioclimatically-affected soil, Rouge River basin, South-Central Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Mahaney, W. C.

    2015-01-01

    Holocene soils in drainage basins of South-Central Ontario, Canada, are generally Fluvisols (Entisols) in floodplains transitioning to Brunisols (Inceptisols), Luvisols (Alfisols) and Podzols (Spodosols) in older terraces and in the glaciated tableland. A single landslide sourced from the highest fluvial terrace in the Rouge basin, with a rubble drop of ~ 12 m emplaced a lobe-shaped mass of reworked stream gravel, glaciolacustrine sediment and till, emplaced approximately 6 m above mean water level at a height roughly equivalent to previously dated mid-Holocene terraces and soils. Clay mineralogy of the soil formed in this transported regolith produced the usual semi-detrital/pedogenic distribution of 1:1 (Si:Al = 1:1), 2:1 and 2:1:1 clay minerals as well as primary minerals consisting of plagioclase feldspar, quartz, mica and calcite. Unexpectedly, the presence of moderate amounts of Ca-smectite in the Bk and Ck horizons, relative to a clay-mineral depleted parent material (Cuk), argues for a soil hydrological change affecting the wetting depth in the deposit. The presence of the uncommon 'maidenhair fern' (Adiantum pedantum) in the mass wasted deposit, a plant capable of high evapotranspiration, is interpreted as producing a bioclimatic disruption limiting soil water penetration to near root depth (wetting depth), thus producing a clay mineral anomaly.

  9. Factors affecting the decision to hospitalise children admitted to the emergency department due to non-fatal suicide attempts by pills

    PubMed Central

    Gokalp, Gamze; Anil, Murat; Bal, Alkan; Bicilioglu, Yuksel; Kamit Can, Fulya; Anil, Ayse Berna

    2016-01-01

    Objective: Suicide attempts (SAs) in the paediatric age group represent an important cause of morbidity and mortality. Our aim was to examine the factors affecting the decision to hospitalize children with a diagnosis of non-fatal SA by pills. Methods: Children <18 years of age admitted with SA by pills during 2014 were evaluated retrospectively. Patients were divided into two groups: Group-I comprised hospitalised patients and Group-II included those who were discharged from the PED. These two groups were compared in terms of clinical and demographic characteristics recorded upon PED admission. Results: A total of 196 patients were included in the study. The number of pills taken for self-poisoning in Group-I (median: 20 pills) was higher than that in Group-II (median: 12 pills) (p < 0.001), and the rate of pathological findings during the first paediatric psychiatric consultation was higher in Group-I (91.1%) than in the Group-II (54.8%) (p < 0.001). Conclusion: Factors affecting the disposition decision in cases of children who performed non-fatal SA via pills included the amount of medication taken for the suicide attempt and the presence of psychiatric disorders, as determined by a paediatric psychiatrist during the acute phase. PMID:27375723

  10. Challenges of river basin management: Current status of, and prospects for, the River Danube from a river engineering perspective.

    PubMed

    Habersack, Helmut; Hein, Thomas; Stanica, Adrian; Liska, Igor; Mair, Raimund; Jäger, Elisabeth; Hauer, Christoph; Bradley, Chris

    2016-02-01

    In the Danube River Basin multiple pressures affect the river system as a consequence of river engineering works, altering both the river hydrodynamics and morphodynamics. The main objective of this paper is to identify the effects of hydropower development, flood protection and engineering works for navigation on the Danube and to examine specific impacts of these developments on sediment transport and river morphology. Whereas impoundments are characterised by deposition and an excess of sediment with remobilisation of fine sediments during severe floods, the remaining five free flowing sections of the Danube are experiencing river bed erosion of the order of several centimetres per year. Besides the effect of interruption of the sediment continuum, river bed degradation is caused by an increase in the sediment transport capacity following an increase in slope, a reduction of river bed width due to canalisation, prohibition of bank erosion by riprap or regressive erosion following base level lowering by flood protection measures and sediment dredging. As a consequence, the groundwater table is lowered, side-arms are disconnected, instream structures are lost and habitat quality deteriorates affecting the ecological status of valuable floodplains. The lack of sediments, together with cutting off meanders, leads also to erosion of the bed of main arms in the Danube Delta and coastal erosion. This paper details the causes and effects of river engineering measures and hydromorphological changes for the Danube. It highlights the importance of adopting a basin-wide holistic approach to river management and demonstrates that past management in the basin has been characterised by a lack of integration. To-date insufficient attention has been paid to the wide-ranging impacts of river engineering works throughout the basin: from the basin headwaters to the Danube Delta, on the Black Sea coast. This highlights the importance of new initiatives that seek to advance knowledge

  11. Challenges of river basin management: Current status of, and prospects for, the River Danube from a river engineering perspective.

    PubMed

    Habersack, Helmut; Hein, Thomas; Stanica, Adrian; Liska, Igor; Mair, Raimund; Jäger, Elisabeth; Hauer, Christoph; Bradley, Chris

    2016-02-01

    In the Danube River Basin multiple pressures affect the river system as a consequence of river engineering works, altering both the river hydrodynamics and morphodynamics. The main objective of this paper is to identify the effects of hydropower development, flood protection and engineering works for navigation on the Danube and to examine specific impacts of these developments on sediment transport and river morphology. Whereas impoundments are characterised by deposition and an excess of sediment with remobilisation of fine sediments during severe floods, the remaining five free flowing sections of the Danube are experiencing river bed erosion of the order of several centimetres per year. Besides the effect of interruption of the sediment continuum, river bed degradation is caused by an increase in the sediment transport capacity following an increase in slope, a reduction of river bed width due to canalisation, prohibition of bank erosion by riprap or regressive erosion following base level lowering by flood protection measures and sediment dredging. As a consequence, the groundwater table is lowered, side-arms are disconnected, instream structures are lost and habitat quality deteriorates affecting the ecological status of valuable floodplains. The lack of sediments, together with cutting off meanders, leads also to erosion of the bed of main arms in the Danube Delta and coastal erosion. This paper details the causes and effects of river engineering measures and hydromorphological changes for the Danube. It highlights the importance of adopting a basin-wide holistic approach to river management and demonstrates that past management in the basin has been characterised by a lack of integration. To-date insufficient attention has been paid to the wide-ranging impacts of river engineering works throughout the basin: from the basin headwaters to the Danube Delta, on the Black Sea coast. This highlights the importance of new initiatives that seek to advance knowledge

  12. Longitudinal Variability of Phosphorus Fractions in Sediments of a Canyon Reservoir Due to Cascade Dam Construction: A Case Study in Lancang River, China

    PubMed Central

    Liu, Qi; Liu, Shiliang; Zhao, Haidi; Deng, Li; Wang, Cong; Zhao, Qinghe; Dong, Shikui

    2013-01-01

    Dam construction causes the accumulation of phosphorus in the sediments of reservoirs and increases the release rate of internal phosphorus (P) loading. This study investigated the longitudinal variability of phosphorus fractions in sediments and the relationship between the contents of phosphorus fractions and its influencing factors of the Manwan Reservoir, Lancang River, Yunnan Province, China. Five sedimentary phosphorus fractions were quantified separately: loosely bound P (ex-P); reductant soluble P (BD-P); metal oxide-bound P (NaOH-P); calcium-bound P (HCl-P), and residual-P. The results showed that the total phosphorus contents ranged from 623 to 899 µg/g and were correlated positively with iron content in the sediments of the reservoir. The rank order of P fractions in sediments of the mainstream was HCl-P>NaOH-P>residual-P>BD-P>ex-P, while it was residual-P>HCl-P>NaOH-P>BD-P>ex-P in those of the tributaries. The contents of bio-available phosphorus in the tributaries, including ex-P, BD-P and NaOH-P, were significantly lower than those in the mainstream. The contents of ex-P, BD-P, NaOH-P showed a similar increasing trend from the tail to the head of the Manwan Reservoir, which contributed to the relatively higher content of bio-available phosphorus, and represents a high bio-available phosphorus releasing risk within a distance of 10 km from Manwan Dam. Correlation and redundancy analyses showed that distance to Manwan Dam and the silt/clay fraction of sediments were related closely to the spatial variation of bio-available phosphorus. PMID:24386180

  13. Geomorphology and River Dynamics of the Lower Copper River, Alaska

    USGS Publications Warehouse

    Brabets, Timothy P.; Conaway, Jeffrey S.

    2009-01-01

    Located in south-central Alaska, the Copper River drains an area of more than 24,000 square miles. The average annual flow of the river near its mouth is 63,600 cubic feet per second, but is highly variable between winter and summer. In the winter, flow averages approximately 11,700 cubic feet per second, and in the summer, due to snowmelt, rainfall, and glacial melt, flow averages approximately 113,000 cubic feet per second, an order of magnitude higher. About 15 miles upstream of its mouth, the Copper River flows past the face of Childs Glacier and enters a large, broad, delta. The Copper River Highway traverses this flood plain, and in 2008, 11 bridges were located along this section of the highway. The bridges cross several parts of the Copper River and in recent years, the changing course of the river has seriously damaged some of the bridges. Analysis of aerial photography from 1991, 1996, 2002, 2006, and 2007 indicates the eastward migration of a channel of the Copper River that has resulted in damage to the Copper River Highway near Mile 43.5. Migration of another channel in the flood plain has resulted in damage to the approach of Bridge 339. As a verification of channel change, flow measurements were made at bridges along the Copper River Highway in 2005-07. Analysis of the flow measurements indicate that the total flow of the Copper River has shifted from approximately 50 percent passing through the bridges at Mile 27, near the western edge of the flood plain, and 50 percent passing through the bridges at Mile 36-37 to approximately 5 percent passing through the bridges at Mile 27 and 95 percent through the bridges at Mile 36-37 during average flow periods. The U.S. Geological Survey's Multi-Dimensional Surface-Water Modeling System was used to simulate water-surface elevation and velocity, and to compute bed shear stress at two areas where the Copper River is affecting the Copper River Highway. After calibration, the model was used to examine the

  14. Prediction and characterization of heat-affected zone formation in tin-bismuth alloys due to nickel-aluminum multilayer foil reaction

    SciTech Connect

    Hooper, R. J.; Davis, C. G.; Johns, P. M.; Adams, D. P.; Hirschfeld, D.; Nino, J. C.; Manuel, M. V.

    2015-06-26

    Reactive multilayer foils have the potential to be used as local high intensity heat sources for a variety of applications. In this study, most of the past research effort concerning these materials have focused on understanding the structure-property relationships of the foils that govern the energy released during a reaction. To improve the ability of researchers to more rapidly develop technologies based on reactive multilayer foils, a deeper and more predictive understanding of the relationship between the heat released from the foil and microstructural evolution in the neighboring materials is needed. This work describes the development of a numerical model for the purpose of predicting heat affected zone size in substrate materials. The model is experimentally validated using a commercially available Ni-Al multilayer foils and alloys from the Sn-Bi binary system. To accomplish this, phenomenological models for predicting the variation of physical properties (i.e., thermal conductivity, density, and heat capacity) with temperature and composition in the Sn-Bi system were utilized using literature data.

  15. Delaware estuary situation reports: Sea-level rise. How could a potential rise in sea level due to global warming affect Delaware. Technical report

    SciTech Connect

    Washburn, P.M.

    1991-01-01

    Our atmosphere is largely transparent to the solar radiation that warms the Earth's surface. But rather than allowing all the warmth to be radiated back into space, clouds and certain gases naturally present in the atmosphere act remarkably like glass in a greenhouse, retaining part of the heat by absorption and reradiation. Although human beings are not the primary cause of the greenhouse effect, many of our activities may enhance it, thereby altering global climate. Scientists who believe the climate balance will shift toward warmer temperatures see rising sea levels as a major consequence of such a change. The intent of the report is to inform the reader of how a rise in sea level may affect the state of Delaware, if predictions of global warming prove correct. Those responsible for managing our natural resources and developed communities should neither ignore nor overreact to potential scenarios for climate warming or sea-level rise. Instead, they should be aware of the range of possibilities for the years ahead as a basis for precautionary action.

  16. Prediction and characterization of heat-affected zone formation in tin-bismuth alloys due to nickel-aluminum multilayer foil reaction

    DOE PAGES

    Hooper, R. J.; Davis, C. G.; Johns, P. M.; Adams, D. P.; Hirschfeld, D.; Nino, J. C.; Manuel, M. V.

    2015-06-26

    Reactive multilayer foils have the potential to be used as local high intensity heat sources for a variety of applications. In this study, most of the past research effort concerning these materials have focused on understanding the structure-property relationships of the foils that govern the energy released during a reaction. To improve the ability of researchers to more rapidly develop technologies based on reactive multilayer foils, a deeper and more predictive understanding of the relationship between the heat released from the foil and microstructural evolution in the neighboring materials is needed. This work describes the development of a numerical modelmore » for the purpose of predicting heat affected zone size in substrate materials. The model is experimentally validated using a commercially available Ni-Al multilayer foils and alloys from the Sn-Bi binary system. To accomplish this, phenomenological models for predicting the variation of physical properties (i.e., thermal conductivity, density, and heat capacity) with temperature and composition in the Sn-Bi system were utilized using literature data.« less

  17. Somatostatin analogues do not affect calcium metabolism in patients with acromegaly and primary hyperparathyroidism [corrected] due to MEN 1-like syndrome.

    PubMed

    Bogazzi, F; Lombardi, M; Russo, D; Sardella, C; Raggi, F; Brogioni, S; Cetani, F; Ceccarelli, C; Mariani, G; Basolo, F; Martino, E

    2011-02-01

    Patients with clinical features of MEN 1 without mutations in the menin gene fulfill the criteria of MEN1-like syndrome. Primary hyperparathyroidism (PHP) is the most frequent clinical finding in both syndromes and is usually treated by surgery. However, PHP has been reported to respond to somatostatin analogues (SSA) in MEN 1 patients. 7 patients with PHP in the context of MEN 1-like syndrome (and absence of mutations in the menin gene) were enrolled in the study and treated with SSA for 6 months for the non-PHP disease before parathyroidectomy. Serum ionized calcium, phosphorus, and PTH concentrations, and 24-h urinary calcium and phosphorus excretion were measured before and after SSA therapy. Mean serum ionized calcium, phosphorus, and PTH concentrations did not significantly change after a 6-month course with SSA. SSA scintigraphy did not reveal uptake in the neck region corresponding to the parathyroid adenoma identified at surgery and confirmed at histology. However, immunohistochemistry revealed SS-type 2A receptor in parathyroid tissue samples of 6 out of 7 patients. SSA therapy does not affect calcium-phosphorus metabolism in patients with MEN 1-like syndrome, suggesting that the drug has no role in controlling PHP in these subset of patients.

  18. Carbon Dioxide Emissions as Affected by Alternative Long-Term Irrigation and Tillage Management Practices in the Lower Mississippi River Valley

    PubMed Central

    Smith, S. F.; Brye, K. R.

    2014-01-01

    Ensuring the sustainability of cultivated soils is an ever-increasing priority for producers in the Lower Mississippi River Valley (LMRV). As groundwater sources become depleted and environmental regulations become more strict, producers will look to alternative management practices that will ensure the sustainability and cost-effectiveness of their production systems. This study was conducted to assess the long-term (>7 years) effects of irrigation (i.e., irrigated and dryland production) and tillage (conventional and no-tillage) on estimated carbon dioxide (CO2) emissions from soil respiration during two soybean (Glycine max L.) growing seasons from a wheat- (Triticum aestivum L.-) soybean, double-cropped production system in the LMRV region of eastern Arkansas. Soil surface CO2 fluxes were measured approximately every two weeks during two soybean growing seasons. Estimated season-long CO2 emissions were unaffected by irrigation in 2011 (P > 0.05); however, during the unusually dry 2012 growing season, season-long CO2 emissions were 87.6% greater (P = 0.044) under irrigated (21.9 Mg CO2 ha−1) than under dryland management (11.7 Mg CO2 ha−1). Contrary to what was expected, there was no interactive effect of irrigation and tillage on estimated season-long CO2 emissions. Understanding how long-term agricultural management practices affect soil respiration can help improve policies for soil and environmental sustainability. PMID:25371912

  19. Carbon dioxide emissions as affected by alternative long-term irrigation and tillage management practices in the lower Mississippi River Valley.

    PubMed

    Smith, S F; Brye, K R

    2014-01-01

    Ensuring the sustainability of cultivated soils is an ever-increasing priority for producers in the Lower Mississippi River Valley (LMRV). As groundwater sources become depleted and environmental regulations become more strict, producers will look to alternative management practices that will ensure the sustainability and cost-effectiveness of their production systems. This study was conducted to assess the long-term (>7 years) effects of irrigation (i.e., irrigated and dryland production) and tillage (conventional and no-tillage) on estimated carbon dioxide (CO2) emissions from soil respiration during two soybean (Glycine max L.) growing seasons from a wheat- (Triticum aestivum L.-) soybean, double-cropped production system in the LMRV region of eastern Arkansas. Soil surface CO2 fluxes were measured approximately every two weeks during two soybean growing seasons. Estimated season-long CO2 emissions were unaffected by irrigation in 2011 (P > 0.05); however, during the unusually dry 2012 growing season, season-long CO2 emissions were 87.6% greater (P = 0.044) under irrigated (21.9 Mg CO2 ha(-1)) than under dryland management (11.7 Mg CO2 ha(-1)). Contrary to what was expected, there was no interactive effect of irrigation and tillage on estimated season-long CO2 emissions. Understanding how long-term agricultural management practices affect soil respiration can help improve policies for soil and environmental sustainability.

  20. Hypoxaemia affects male reproduction: a case study of how to differentiate between primary and secondary hypoxic testicular toxicity due to chemical exposure.

    PubMed

    Bomhard, Ernst M; Gelbke, Heinz-Peter

    2013-07-01

    Classification for fertility is based on two conditions, namely on evidence of an adverse effect on sexual function and fertility and that the effect is not secondary to other toxic effects. To decide on an adverse effect is a relatively simple day-to-day decision in toxicology but whether this effect is secondary often leads to serious controversy. As the seminiferous epithelium operates on the verge of hypoxia, oxygen deficit can lead to secondary impairment of testicular function. This is well known from healthy mountaineers exposing themselves to high altitude. They have reduced blood oxygen content that goes in parallel with impairment of testicular function and this effect remains for some time in spite of a compensatory polycythaemia. Similar findings are described for experimental animals exposed to hypobaric oxygen/high altitude. In addition, testicular function is affected in severe diseases in humans associated with systemic oxygen deficit like chronic obstructive pulmonary disease, sickle cell disease or beta-thalassaemia as well as in transgenic animals simulating haemolytic anaemia or sickle cell disease. The problem of insufficient oxygen supply as the underlying cause for testicular impairment has received relatively little attention in toxicology, mainly because blood oxygen content is generally not measured in these animal experiments. The difficulties associated with the decision whether testicular toxicity is primary or secondary to hypoxia are exemplified by the results of inhalation studies with nickel subsulphide and gallium arsenide (GaAs). Both of these particulate substances lead to severe lung toxicity that might impair oxygen uptake, but testicular toxicity is only observed with GaAs. This may first be explained by different effects on the blood: nickel subsulphide inhalation leads to a compensatory erythropoiesis that may mitigate pulmonary lack of oxygen uptake. In contrast, GaAs exposure is associated with microcytic haemolytic

  1. Geochemical distribution of arsenic, cadmium, lead and zinc in river sediments affected by tailings in Zimapán, a historical polymetalic mining zone of México

    NASA Astrophysics Data System (ADS)

    Espinosa, Erik; Armienta, María Aurora; Cruz, Olivia; Aguayo, Alejandra; Ceniceros, Nora

    2009-10-01

    In the historical mining zone of Zimapán, México, unprotected tailings deposits are supplying contaminants to the local fluvial system. This research was conducted to assess the environmental hazard of these wastes and river sediments by determining the input, transport and seasonal variability of arsenic, cadmium, lead and zinc, and their speciation by an operationally defined scheme of decreasing lability: F1, fraction soluble in deionized water; F2, associated to carbonates; F3, oxides and hydroxides of iron; F4, sulfides and organic matter; F5, residual. Higher total concentrations of Cd, Pb and Zn were present in sediments in the dry season regarding the rainy season. In the dry season, As and Pb were principally associated with the more stable F3 and F5 fractions, whereas Cd was in F2 and F5, and Zn in F3, F2 and F5. In the rainy season the association was mainly F3 for As, while F2 and F3 contained most Cd, Pb and Zn. This fractionation indicates that the environmental hazard of Cd, Pb and Zn enhances upon a pH decrease due to their proportion in the carbonatic fraction, and shows a mobility increase during the rainy season.

  2. Assessment of the water self-purification capacity on a river affected by organic pollution: application of chemometrics in spatial and temporal variations.

    PubMed

    González, S Oliva; Almeida, C A; Calderón, M; Mallea, M A; González, P

    2014-09-01

    Water pollution caused by organic matter is a major global problem which requires continuous evaluation. Multivariate statistical analysis was applied to assess spatial and temporal changes caused by natural and anthropogenic phenomena along Potrero de los Funes River. Cluster analysis (CA), principal component analysis (PCA) and analysis of variance (ANOVA) were applied to a data set collected throughout a period of 3 years (2010-2012), which monitored 22 physical, chemical and biological parameters. Content of dissolved oxygen in water and biochemical oxygen demand in a watercourse are indicators of pollution caused by organic matter. For this reason, the Streeter-Phelps model was used to evaluate the water self-purification capacity. Hierarchical cluster analysis grouped the sampling sites based on the similarity of water quality characteristics. PCA resulted in two latent factors explaining 75.2 and 17.6 % of the total variance in water quality data sets. Multidimensional ANOVA suggested that organic pollution is mainly due to domestic wastewater run-offs and anthropogenic influence as a consequence of increasing urbanization and tourist influx over the last years. Besides, Streeter-Phelps parameters showed a low reaeration capacity before dam with low concentration of dissolved oxygen. Furthermore, self-purification capacity loss was correlated with the decrease of the Benthic Index. This measurement suggested that biological samplings complement the physical-chemical analysis of water quality.

  3. Does trans-10, cis-12 conjugated linoleic acid affect the intermediary glucose and energy expenditure of dairy cows due to repartitioning of milk component synthesis?

    PubMed

    Benninghoff, Jens; Metzger-Petersen, Katrin; Tröscher, Arnulf H A; Südekum, Karl-Heinz

    2015-11-01

    The overall goal of this study was to evaluate if intermediary energy metabolism of cows fed with trans-10, cis-12 conjugated linoleic acid (CLA) was modified such that milk-energy compounds were produced with less intermediary energy expenditure as compared to control cows. Published data on supplemented CLA were assembled. The extent was calculated to which the trans-10, cis-12 CLA isomer has an impact on glucose and energy conversion in the mammary gland by modifying glucose equivalent supply and energy required for fatty acid (FA) and fat synthesis, and if this will eventually lead to an improved glucose and energy status of CLA-supplemented high-yielding dairy cows. A possible relationship between CLA supplementation level and milk energy yield response was also studied. Calculations were conducted separately for orally and abomasally administered CLA and based on energy required for supply of glucose equivalents, i.e. lactose, glycerol and NADPH2. Further, modifications of milk FA profile due to CLA supplementation were considered when energy expenditures for FA and fat synthesis were quantified. Differences in yields between control and CLA groups were transformed into glucose energy equivalents. Only abomasal infusion (r(2) = 0.31) but not oral CLA administration (r(2) = 0.11) supplementation to dairy cow diets resulted in less glucose equivalent energy. Modifications of milk FA profiles also saved energy but the relationship with CLA supplementation was weaker for abomasal infusion (r(2) = 0.06) than oral administration (r(2) = 0.38). On average, 10 g/d of abomasally infused trans-10, cis-12 CLA saved 1.1 to 2.3 MJ net energy expressed as glucose equivalents, whereas both positive and negative values were observed when the trans-10, cis-12 CLA was fed to the cows. This study revealed a weak to moderate dose-dependent relationship between the amount of trans-10, cis-12 CLA administered and the amount of energy in glucose equivalents and energy for the

  4. Does trans-10, cis-12 conjugated linoleic acid affect the intermediary glucose and energy expenditure of dairy cows due to repartitioning of milk component synthesis?

    PubMed

    Benninghoff, Jens; Metzger-Petersen, Katrin; Tröscher, Arnulf H A; Südekum, Karl-Heinz

    2015-11-01

    The overall goal of this study was to evaluate if intermediary energy metabolism of cows fed with trans-10, cis-12 conjugated linoleic acid (CLA) was modified such that milk-energy compounds were produced with less intermediary energy expenditure as compared to control cows. Published data on supplemented CLA were assembled. The extent was calculated to which the trans-10, cis-12 CLA isomer has an impact on glucose and energy conversion in the mammary gland by modifying glucose equivalent supply and energy required for fatty acid (FA) and fat synthesis, and if this will eventually lead to an improved glucose and energy status of CLA-supplemented high-yielding dairy cows. A possible relationship between CLA supplementation level and milk energy yield response was also studied. Calculations were conducted separately for orally and abomasally administered CLA and based on energy required for supply of glucose equivalents, i.e. lactose, glycerol and NADPH2. Further, modifications of milk FA profile due to CLA supplementation were considered when energy expenditures for FA and fat synthesis were quantified. Differences in yields between control and CLA groups were transformed into glucose energy equivalents. Only abomasal infusion (r(2) = 0.31) but not oral CLA administration (r(2) = 0.11) supplementation to dairy cow diets resulted in less glucose equivalent energy. Modifications of milk FA profiles also saved energy but the relationship with CLA supplementation was weaker for abomasal infusion (r(2) = 0.06) than oral administration (r(2) = 0.38). On average, 10 g/d of abomasally infused trans-10, cis-12 CLA saved 1.1 to 2.3 MJ net energy expressed as glucose equivalents, whereas both positive and negative values were observed when the trans-10, cis-12 CLA was fed to the cows. This study revealed a weak to moderate dose-dependent relationship between the amount of trans-10, cis-12 CLA administered and the amount of energy in glucose equivalents and energy for the

  5. [Factors affecting the participation of bacteria of the genus Bdellovibrio in the self-purification processes in the Syr Darya River].

    PubMed

    Lambina, V A; Ledova, L A; Kutliev, D K

    1983-01-01

    The effect of season, temperature and abundance of microflora on the interrelations between bdellovibrions and host-bacteria in the syr Daryo river compared with the Oka has been studied. These factors and composition of allochthonic gram-negative bacteria in the river influence on the abundance of Bdellovibrio and extent its participation in the self-purification of basins.

  6. In vivo induction of antioxidant response and oxidative stress associated with genotoxicity and histopathological alteration in two commercial fish species due to heavy metals exposure in northern India (Kali) river.

    PubMed

    Fatima, Mahino; Usmani, Nazura; Firdaus, Fakiha; Zafeer, Mohammad Faraz; Ahmad, Shafeeque; Akhtar, Kafil; Dawar Husain, S M; Ahmad, Mir Hilal; Anis, Ehraz; Mobarak Hossain, M

    2015-01-01

    Heavy metals can significantly bioaccumulate in fish tissues. The step wise mechanism of heavy metal toxicities on fish health is still limited. The present study assessed the tissue-specific antioxidant response and oxidative stress biomarkers of commercially important fish species namely, Channa striatus and Heteropneustes fossilis inhabiting Kali River of northern India where heavy-metal load is beyond the World Health Organisation - maximum permissible limits. Heavy metals chromium (Cr), nickel (Ni), lead (Pb) and cadmium (Cd) were elevated in both fish species compared to recommended values of the Federal Environmental Protection Agency (FEPA), 1999 for edible fishes. Reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CATA) activities in all tissues (brachial, neural, renal and hepatic) were altered. Cellular lipid and protein compromisation in both fishes induced by heavy metals was determined by lipid peroxidation (LPO) and protein carbonylation (PC) assays. Micronucleus (MN) test of erythrocytes and comet assay of liver cells confirmed genotoxicity. Histopathology of the liver, kidney and brain of affected fishes was distorted significantly with its reference fishes thereby affecting the quality and quantity of these fish stocks. This raises a serious concern as these fishes are consumed by the local population which would ultimately affect human health. PMID:26191657

  7. In vivo induction of antioxidant response and oxidative stress associated with genotoxicity and histopathological alteration in two commercial fish species due to heavy metals exposure in northern India (Kali) river.

    PubMed

    Fatima, Mahino; Usmani, Nazura; Firdaus, Fakiha; Zafeer, Mohammad Faraz; Ahmad, Shafeeque; Akhtar, Kafil; Dawar Husain, S M; Ahmad, Mir Hilal; Anis, Ehraz; Mobarak Hossain, M

    2015-01-01

    Heavy metals can significantly bioaccumulate in fish tissues. The step wise mechanism of heavy metal toxicities on fish health is still limited. The present study assessed the tissue-specific antioxidant response and oxidative stress biomarkers of commercially important fish species namely, Channa striatus and Heteropneustes fossilis inhabiting Kali River of northern India where heavy-metal load is beyond the World Health Organisation - maximum permissible limits. Heavy metals chromium (Cr), nickel (Ni), lead (Pb) and cadmium (Cd) were elevated in both fish species compared to recommended values of the Federal Environmental Protection Agency (FEPA), 1999 for edible fishes. Reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CATA) activities in all tissues (brachial, neural, renal and hepatic) were altered. Cellular lipid and protein compromisation in both fishes induced by heavy metals was determined by lipid peroxidation (LPO) and protein carbonylation (PC) assays. Micronucleus (MN) test of erythrocytes and comet assay of liver cells confirmed genotoxicity. Histopathology of the liver, kidney and brain of affected fishes was distorted significantly with its reference fishes thereby affecting the quality and quantity of these fish stocks. This raises a serious concern as these fishes are consumed by the local population which would ultimately affect human health.

  8. Biogeochemical factors affecting the distribution, speciation, and transport of Hg species in the Deûle and Lys Rivers (Northern France).

    PubMed

    Daye, Mirna; Kadlecova, Milada; Ouddane, Baghdad

    2015-02-01

    The Deûle River is a highly polluted River by heavy metals caused by the historical discharges of ore minerals from the former ore smelter "Metaleurop." The potential mercury (Hg) pollution in the Deûle River implicates the importance of Hg distribution study in the river. As well as to configure the different biogeochemical factors that control the distribution and the potential transport of Hg to distant places. Four different sites were studied as follows: D-A (Deûle River, a site located upstream the river), D-B (Deûle River, a site located near a Zn, Pb, Cu, and Ni smelter that closed in 2003), L-C (Lys River, a site located upstream the confluence of the Deûle River with Lys River), and L-D (downstream the rivers confluence). Different Hg analyses were performed including total mercury in sediment (HgTS), methylmercury (MeHg) in sediment, total mercury in pore water (HgTPW), total mercury in surface water (HgTD), and total suspended particulate Hg in water (HgTP). HgTS decreases downstream from the Deûle River sites with a mean value of 11 ± 0.34 mg/kg to Lys River site (L-D) with a mean value of 0.53 ± 0.02 mg/kg at the confluence. The unaffected side of the Lys River, localized before the confluence (L-C), is characterized by low HgTS of an average value of 0.042 ± 0.003 mg/kg and high % MeHg reaching 4.2 %. Whereas, the highly contaminated Deûle sites are designated by low % MeHg with an average value of 0.053 %. Low pristine environments like that found in L-C site with more favorable biogeochemical conditions of lower concentrations of HgTS, sulfides, and Corg host more active biotic methylation than that of the highly polluted Deûle sites with high concentrations of HgTS and sulfides concentrations. Methylation in D-B (the closet site to Metaleurop smelter) is an old and recent methylation activity that has contributed to MeHg accumulation in the sediments as opposed to the exclusive recent events of methylation in Lys sites. Me

  9. Development of river flood model in lower reach of urbanized river basin

    NASA Astrophysics Data System (ADS)

    Yoshimura, Kouhei; Tajima, Yoshimitsu; Sanuki, Hiroshi; Shibuo, Yoshihiro; Sato, Shinji; Lee, SungAe; Furumai, Hiroaki; Koike, Toshio

    2014-05-01

    Japan, with its natural mountainous landscape, has demographic feature that population is concentrated in lower reach of elevation close to the coast, and therefore flood damage with large socio-economic value tends to occur in low-lying region. Modeling of river flood in such low-lying urbanized river basin is complex due to the following reasons. In upstream it has been experienced urbanization, which changed land covers from natural forest or agricultural fields to residential or industrial area. Hence rate of infiltration and runoff are quite different from natural hydrological settings. In downstream, paved covers and construct of sewerage system in urbanized areas affect direct discharges and it enhances higher and faster flood peak arrival. Also tidal effect from river mouth strongly affects water levels in rivers, which must be taken into account. We develop an integrated river flood model in lower reach of urbanized areas to be able to address above described complex feature, by integrating model components: LSM coupled distributed hydrological model that models anthropogenic influence on river discharges to downstream; urban hydrological model that simulates run off response in urbanized areas; Saint Venant's equation approximated river model that integrates upstream and urban hydrological models with considering tidal effect from downstream. These features are integrated in a common modeling framework so that model interaction can be directly performed. The model is applied to the Tsurumi river basin, urbanized low-lying river basin in Yokohama and model results show that it can simulate water levels in rivers with acceptable model errors. Furthermore the model is able to install miscellaneous water planning constructs, such as runoff reduction pond in urbanized area, flood control field along the river channel, levee, etc. This can be a useful tool to investigate cost performance of hypothetical water management plan against impact of climate change in

  10. Factors affecting the geochemistry of a thick, subbituminous coal bed in the Powder River Basin: volcanic, detrital, and peat-forming processes

    USGS Publications Warehouse

    Crowley, S.S.; Ruppert, L.F.; Belkin, H.E.; Stanton, R.W.; Moore, T.A.

    1993-01-01

    The inorganic geochemistry and mineralogy of three cores from the Anderson-Dietz 1 coal bed, a 15.2-m-thick subbituminous coal bed in the Tongue River Member (Paleocene) of the Fort Union Formation, were examined (1) to determine if the cores could be correlated by geochemical composition alone over a total distance of 2 km and (2) to identify the major factors that influenced the geochemistry of the coal bed. Chemical data (46 elements on a coal-ash basis) for 81 coal samples and 4 carbonaceous rock samples, with most samples representing a 0.6-m-thick (2-ft) interval of core, were grouped into compositional clusters by means of cluster analysis. Seven major clusters were produced; two of these clusters can be used to correlate the coal bed throughout the study area. Data from scanning electron and optical microscope analyses indicate that several factors influenced the geochemistry of the Anderson-Dietz 1 coal bed. The majority of mineral grains in the coal bed are interpreted to be detrital (water borne); evidence includes the presence of rounded to subrounded quartz grains having two-phase, aqueous fluid inclusions characteristic of hydrothermal or low-to-moderate grade metamorphic quartz. These quartz grains are found throughout the coal bed but are most abundant in samples from the midpart of the bed, which was influenced by detrital input associated with the deposition of the clastic rocks that form the split between the Anderson and Dietz 1 coal beds 900 m to the east of the study area. In addition to the detrital minerals mentioned above, volcanic ash that was fluvially transported to the sites of peat deposition or possibly deposited as air-fall volcanic ash also affected the geochemistry of the coal bed. For example, crandallite(?), a mineral reported to form as an alteration product of volcanic ash, is found in seven samples from the coal bed. The presence of quartz grains containing silicate-melt inclusions in eight samples from the coal bed

  11. TDS-Eh graph analysis: a new water quality index and rural water supply implications of a river affected by mining in south-eastern Nigeria

    NASA Astrophysics Data System (ADS)

    Ezekwe, I. C.; Aisubeogun, A. O.; Chima, G. N.; Odubo, E.

    2012-03-01

    The Ivo River Basin of south-eastern Nigeria is a water scarce and mining region, which suffers from water scarcity. The influence of mining activities on the quality of the Ivo River and its capacity for community water supply was investigated. Also the efficacy of TDS-Eh graph in explaining water quality was presented. Results indicated that the TDS-Eh graph highlights subtle chemical relationships which control water quality and provide a simple but generic pollution index for rapid water quality assessment. It was also discovered that the Ivo River could become an adequate alternative to groundwater as a source of rural water supply in the study area with an estimated average daily discharge of 6726000 L and a rural population of less than 200000 persons. The Ivo River meets the WHO drinking water standards in 20 physicochemical water quality parameters (pH, temperature, conductivity, turbidity, salinity, TDS, Eh, alkalinity, chloride, nitrate, sulfate, phosphate, calcium, magnesium, iron, manganese, zinc, lead and cadmium) analyzed and can therefore (with little treatment) provide up to 133.4% of average community water demand and 83.8% of maximum community water demand. The impact of mining on Ivo River quality was found to have been moderated by the presence of carbonate rocks which may have enhanced the precipitation of heavy metals from the river.

  12. Hydrological Signature From River-Floodplain Interactions

    NASA Astrophysics Data System (ADS)

    Paiva, R. C. D.; Fleischmann, A. S.; Collischonn, W.; Sorribas, M.; Pontes, P. R.

    2015-12-01

    Understanding river-floodplain hydraulic processes is fundamental to promote comprehension of related water paths, biogeochemicalcyclesand ecosystems. Large river basins around the globe present enormous developed floodplains, which strongly affect flood waves and water dynamics. Since most of these river-floodplain interactions are not monitored, it is interesting to develop strategies to understand such processes through characteristic hydrological signatures, e.g. hydrographs. We studied observed hydrographs from large South American rivers and found that in several cases rivers with extensive wetlands present a particular hydrograph shape, with slower rising limb in relation to the receding one, due to storage effects and the associated decrease of wave celerity with stage. A negative asymmetry in the hydrograph is generated, which is higher when more water flows through floodplains upstream of the observed point. Finally, we studied the Amazon basin using gauged information and simulation results from the MGB-IPH regional hydrological model. Major rivers with larger wetland areas (e.g. Purus, Madeira and Juruá) were identified with higher negative asymmetry in their hydrographs. The hydrodynamic model was run in scenarios with and without floodplains, and results supported that floodplain storage affects hydrographs in creating a negative asymmetry, besides attenuating peaks, increasing hydrograph smoothness and increasing minimum flows. Finally, different wetland types could be distinguished with hydrograph shape, e.g. differing wetlands fed by local rainfall from wetlands due to overbank flow (floodplains). These metrics and concepts on hydrograph features have great potential to infer about river-floodplain processes from large rivers and wetland systems.

  13. Water geochemistry of the Qiantangjiang River, East China: Chemical weathering and CO2 consumption in a basin affected by severe acid deposition

    NASA Astrophysics Data System (ADS)

    Liu, Wenjing; Shi, Chao; Xu, Zhifang; Zhao, Tong; Jiang, Hao; Liang, Chongshan; Zhang, Xuan; Zhou, Li; Yu, Chong

    2016-09-01

    The chemical composition of the Qiantangjiang River, the largest river in Zhejiang province in eastern China, was measured to understand the chemical weathering of rocks and the associated CO2 consumption and anthropogenic influences within a silicate-dominated river basin. The average total dissolved solids (TDS, 113 mg l-1) and total cation concentration (TZ+, 1357 μeq l-1) of the river waters are comparable with those of global major rivers. Ca2+ and HCO3- followed by Na2+ and SO42-, dominate the ionic composition of the river water. There are four major reservoirs (carbonates, silicates, atmospheric and anthropogenic inputs) contributing to the total dissolved load of the investigated rivers. The dissolved loads of the rivers are dominated by both carbonate and silicate weathering, which together account for about 76.3% of the total cationic load origin. The cationic chemical weathering rates of silicate and carbonate for the Qiantangjiang basin are estimated to be approximately 4.9 ton km-2 a-1 and 13.9 ton km-2 a-1, respectively. The calculated CO2 consumption rates with the assumption that all the protons involved in the weathering reaction are provided by carbonic acid are 369 × 103 mol km-2 a-1 and 273 × 103 mol km-2 a-1 by carbonate and silicate weathering, respectively. As one of the most severe impacted area by acid rain in China, H2SO4 from acid precipitation is also an important proton donor in weathering reactions. When H2SO4 is considered, the CO2 consumption rates for the river basin are estimated at 286 × 103 mol km-2 a-1 for carbonate weathering and 211 × 103 mol km-2 a-1 for silicate weathering, respectively. The results highlight that the drawdown effect of CO2 consumption by carbonate and silicate weathering can be largely overestimated if the role of sulfuric acid is ignored, especially in the area heavily impacted by acid deposition like Qiantangjiang basin. The actual CO2 consumption rates (after sulfuric acid weathering effect

  14. On the Use of Hydrological Models and Satellite Data to Study the Water Budget of River Basins Affected by Human Activities: Examples from the Garonne Basin of France

    NASA Astrophysics Data System (ADS)

    Martin, Eric; Gascoin, Simon; Grusson, Youen; Murgue, Clément; Bardeau, Mélanie; Anctil, François; Ferrant, Sylvain; Lardy, Romain; Le Moigne, Patrick; Leenhardt, Delphine; Rivalland, Vincent; Sánchez Pérez, José-Miguel; Sauvage, Sabine; Therond, Olivier

    2016-03-01

    Natural and anthropogenic forcing factors and their changes significantly impact water resources in many river basins around the world. Information on such changes can be derived from fine scale in situ and satellite observations, used in combination with hydrological models. The latter need to account for hydrological changes caused by human activities to correctly estimate the actual water resource. In this study, we consider the catchment area of the Garonne river (in France) to investigate the capabilities of space-based observations and up-to-date hydrological modeling in estimating water resources of a river basin modified by human activities and a changing climate. Using the ISBA-MODCOU and SWAT hydrological models, we find that the water resources of the Garonne basin display a negative climate trend since 1960. The snow component of the two models is validated using the moderate-resolution imaging spectroradiometer snow cover extent climatology. Crop sowing dates based on remote sensing studies are also considered in the validation procedure. Use of this dataset improves the simulated evapotranspiration and river discharge amounts when compared to conventional data. Finally, we investigate the benefit of using the MAELIA multi-agent model that accounts for a realistic agricultural and management scenario. Among other results, we find that changes in crop systems have significant impacts on water uptake for agriculture. This work constitutes a basis for the construction of a future modeling framework of the sociological and hydrological system of the Garonne river region.

  15. Morphological, hydrological, biogeochemical and ecological changes and challenges in river restoration - the Thur River case study

    NASA Astrophysics Data System (ADS)

    Schirmer, M.; Luster, J.; Linde, N.; Perona, P.; Mitchell, E. A. D.; Barry, D. A.; Hollender, J.; Cirpka, O. A.; Schneider, P.; Vogt, T.; Radny, D.; Durisch-Kaiser, E.

    2014-06-01

    River restoration can enhance river dynamics, environmental heterogeneity and biodiversity, but the underlying processes governing the dynamic changes need to be understood to ensure that restoration projects meet their goals, and adverse effects are prevented. In particular, we need to comprehend how hydromorphological variability quantitatively relates to ecosystem functioning and services, biodiversity as well as ground- and surface water quality in restored river corridors. This involves (i) physical processes and structural properties, determining erosion and sedimentation, as well as solute and heat transport behavior in surface water and within the subsurface; (ii) biogeochemical processes and characteristics, including the turnover of nutrients and natural water constituents; and (iii) ecological processes and indicators related to biodiversity and ecological functioning. All these aspects are interlinked, requiring an interdisciplinary investigation approach. Here, we present an overview of the recently completed RECORD (REstored CORridor Dynamics) project in which we combined physical, chemical, and biological observations with modeling at a restored river corridor of the perialpine Thur River in Switzerland. Our results show that river restoration, beyond inducing morphologic changes that reshape the river bed and banks, triggered complex spatial patterns of bank infiltration, and affected habitat type, biotic communities and biogeochemical processes. We adopted an interdisciplinary approach of monitoring the continuing changes due to restoration measures to address the following questions: How stable is the morphological variability established by restoration? Does morphological variability guarantee an improvement in biodiversity? How does morphological variability affect biogeochemical transformations in the river corridor? What are some potential adverse effects of river restoration? How is river restoration influenced by catchment-scale hydraulics

  16. Physicochemical characteristics of the hyporheic zone affect redd site selection of chum salmon and fall chinook salmon in the Columbia River

    SciTech Connect

    Geist, David R. ); Hanrahan, Timothy P. ); Arntzen, Evan V. ); McMichael, Geoffrey A. ); Murray, Christopher J. ); Chien, Yi-Ju )

    2002-11-01

    Chum salmon Oncorhynchus keta and fall chinook salmon O. tshawytscha spawned at different locations in the vicinity of Ives Island, Washington, a side channel to the Columbia River downstream of Bonneville Dam. We hypothesized that measurements of water depth, substrate size, and water velocity alone would not explain the separation in spawning areas and began a 2-year investigation of physicochemical characteristics of the hyporheic zone. We found that chum salmon spawned in upwelling water that was significantly warmer than the surrounding river water. In contrast, fall chinook salmon constructed redds at downwelling sites where there was no difference in temperature between the river and its bed. Understanding the specific features that are important for chum salmon and fall chinook salmon redd site selection at Ives Island will be useful to resource managers attempting to maximize available spawning habitat for these species within the constraints imposed by other water resource needs.

  17. Signal crayfish as zoogeomorphic agents: diel patterns of fine sediment suspension in a crayfish-affected river and the implications for fine sediment fluxes and dynamics

    NASA Astrophysics Data System (ADS)

    Rice, Stephen; Johnson, Matthew; Reeds, Jake; Longstaff, Holly; Extence, Chris

    2013-04-01

    The signal crayfish (Pacifasticus leniusculus) is a formidable invasive species that has had a deleterious impact on native freshwater fauna across Europe. We contend that the impact of this animal extends beyond ecology into geomorphology and hypothesise that crayfish are significant agents of fine sediment recruitment and mobilisation, with potentially profound impacts on water quality, substrate quality and fine sediment fluxes. Building on pioneering work by colleagues at Queen Mary University, London this poster considers the role of crayfish in fine sediment suspension in a lowland, gravel-bed river. The hypothesis that nocturnal increases in crayfish activity are associated with a greater frequency of sediment suspension events and increases in ambient turbidity, is tested. Strong diel fluctuations in water turbidity were recorded at several sites on the Brampton Arm of the River Nene in England, a river heavily populated by signal crayfish, during August and September 2012. With the exception of three summer flood events, stage measurements during the same period were essentially flat, ruling out a hydraulic cause for overnight rises in turbidity. Water samples collected at midnight and at midday at one site confirm this diel pattern for suspended sediment concentration. Higher mean turbidity values overnight are associated with an increase in the magnitude and frequency of isolated turbidity spikes or events and this is consistent with crayfish nocturnalism. In particular, we suspect that turbidity events are caused by the construction and maintenenance of burrows and by interactions between crayfish and the river bed while foraging, fighting and avoiding each other. Tying the diel SSC signal directly to crayfish activity proved difficult, but several lines of argument presented here suggest that crayfish are the most likely cause of the diel pattern. These results provide substantial support for the idea that signal crayfish are important zoogeomorphic

  18. Sediment Dynamics Affecting the Threatened Santa Ana Sucker in the Highly-modified Santa Ana River and Inset Channel, Southern California, USA

    NASA Astrophysics Data System (ADS)

    Minear, J. T.; Wright, S. A.

    2015-12-01

    In this study, we investigate the sediment dynamics of the low-flow channel of the Santa Ana River that is formed by wastewater discharges and contains some of the last remaining habitat of the Santa Ana Sucker (Catostomus santaanae). The Santa Ana River is a highly-modified river draining the San Bernardino Mountains and Inland Empire metropolitan area east of Los Angeles. Home to over 4 million people, the watershed provides habitat for the federally-threatened Santa Ana Sucker, which presently reside within the mainstem Santa Ana River in a reach supported by year-round constant discharges from water treatment plants. The nearly constant low-flow wastewater discharges and infrequent runoff events create a small, approximately 8 m wide, inset channel within the approximately 300 m wide mainstem channel that is typically dry except for large flood flows. The sediment dynamics within the inset channel are characterized by constantly evolving bed substrate and sediment transport rates, and occasional channel avulsions. The sediment dynamics have large influence on the Sucker, which rely on coarse-substrate (gravel and cobble) for their food production. In WY 2013 through the present, we investigated the sediment dynamics of the inset channel using repeat bathymetric and substrate surveys, bedload sampling, and discharge measurements. We found two distinct phases of the inset channel behavior: 1. 'Reset' flows, where sediment-laden mainstem discharges from upstream runoff events result in sand deposition in the inset channel or avulse the inset channel onto previously dry riverbed; and 2. 'Winnowing' flows, whereby the sand within the inset channel is removed by clear-water low flows from the wastewater treatment plant discharges. Thus, in contrast to many regulated rivers where high flows are required to flush fine sediments from the bed (for example, downstream from dams), in the Santa Ana River the low flows from wastewater treatment plants serve as the flushing

  19. Meteorological characteristics and overland precipitation impacts of atmospheric rivers affecting the West coast of North America based on eight years of SSM/I satellite observations

    USGS Publications Warehouse

    Neiman, P.J.; Ralph, F.M.; Wick, G.A.; Lundquist, J.D.; Dettinger, M.D.

    2008-01-01

    The pre-cold-frontal low-level jet within oceanic extratropical cyclones represents the lower-tropospheric component of a deeper corridor of concentrated water vapor transport in the cyclone warm sector. These corridors are referred to as atmospheric rivers (ARs) because they are narrow relative to their length scale and are responsible for most of the poleward water vapor transport at midlatitudes. This paper investigates landfalling ARs along adjacent north- and south-coast regions of western North America. Special Sensor Microwave Imager (SSM/ I) satellite observations of long, narrow plumes of enhanced integrated water vapor (IWV) were used to detect ARs just offshore over the eastern Pacific from 1997 to 2005. The north coast experienced 301 AR days, while the south coast had only 115. Most ARs occurred during the warm season in the north and cool season in the south, despite the fact that the cool season is climatologically wettest for both regions. Composite SSM/I IWV analyses showed landfalling wintertime ARs extending northeastward from the tropical eastern Pacific, whereas the summertime composites were zonally oriented and, thus, did not originate from this region of the tropics. Companion SSM/I composites of daily rainfall showed significant orographic enhancement during the landfall of winter (but not summer) ARs. The NCEP-NCAR global reanalysis dataset and regional precipitation networks were used to assess composite synoptic characteristics and overland impacts of landfalling ARs. The ARs possess strong vertically integrated horizontal water vapor fluxes that, on average, impinge on the West Coast in the pre-cold-frontal environment in winter and post-cold-frontal environment in summer. Even though the IWV in the ARs is greater in summer, the vapor flux is stronger in winter due to much stronger flows associated with more intense storms. The landfall of ARs in winter and north-coast summer coincides with anomalous warmth, a trough offshore, and

  20. Magnitude and frequency analysis on river width widening caused by Typhoon Morakot in the Kaoping River watershed, Taiwan

    NASA Astrophysics Data System (ADS)

    Yang, S. Y.; Jan, C. D.; Wang, Y. C.

    2014-12-01

    Active evolving rivers are some of the most dynamic and sensitive parts of landscapes. From geologic and geomorphic perspectives, a stable river channel can adjust its width, depth, and slope to prevent significant aggradation or degradation caused by external triggers, e.g., hydrologic events caused by typhoon storms. In particular, the processes of lateral riverbank erosion play a majorly important role in forming horizontal river geomorphology, dominating incised river widens and meanders. Sediment materials produced and mobilized from riverbanks can also be substantial sediment supplying into river channel networks, affecting watershed sediment yield. In Taiwan, the geological and climatic regimes usually combine to generate severely lateral erosion and/or riverbed deposition along river channels, causing the significant change in river width. In the August of 2009, Typhoon Morakot brought severe rainfall of about 2000 mmin Southern Taiwan during three days at the beginning of Aug. 5, leading to significant changes in geomorphic system. Here we characterized river width widening (including Cishan, Laonong, and Ilao Rivers) in the Kaoping River watershed after Typhoon Morakot disturbance interpreted through a power law. On the basis of a temporal pair (2008 and 2009) of Formosat-II (Formosa satellite II) images analysis, the river channels were digitalized within geographic information system (GIS), and river widths were extracted per 100 m along the rivers, then differentiating the adjustment of river width before and after Typhoon Morkot. The river width adjusted from -83 m (contracting) to 1985 m (widening), with an average of 170 m. The noncumulative frequency-magnitude distribution for river width adjustment caused by Typhoon Morakot in the study area satisfies a power-law relation with a determined coefficient (r2) of 0.95, over the range from 65 m to 2373m in the study area. Moreover, the value of the power-law exponent is equal to -2.09. This pattern

  1. Changes in channel geometry of six eruption-affected tributaries of the Lewis River, 1980-82, Mount St. Helens, Washington

    USGS Publications Warehouse

    Martinson, H.A.; Finneran, S.D.; Topinka, L.J.

    1984-01-01

    The May 18, 1980, eruption of Mount St. Helens generated a lateral blast, lahars and tephra deposits that altered tributary channels in the Lewis River drainage basin. In order to assess potential flood hazards, study channel adjustments, and construct a sediment budget for the perturbed drainages on the east and southeast flanks of the volcano, channel cross sections were monumented and surveyed on Pine Creek, Muddy River, and Smith Creek during September and October of 1980. Additional cross sections were monumented and surveyed on Swift Creek, Bean Creek, and Clearwater Creek during the summer of 1981. The network of 88 channel cross sections has been resurveyed annually. Selected cross sections have been surveyed more frequently, following periods of higher flow. The repetitive cross-section surveys provide measurements of bank erosion or accretion and of channel erosion or aggradation. The report presents channel cross-section profiles constructed from the survey data collected during water years 1980-82. (USGS)

  2. Pesticides in surface water of the Yakima River basin, Washington, 1999-2000; their occurrence and an assessment of factors affecting concentrations and loads

    USGS Publications Warehouse

    Ebbert, James C.; Embrey, Sandra S.

    2002-03-19

    Pesticide losses, defined as the ratio of the amount discharged from a basin from May 1999 through January 2000 divided by the amount applied during 1999, were estimated for Moxee and Granger Drains and the Yakima River at Kiona. Losses ranged from less than 0.01 to 1.5 percent of pesticides applied and are comparable to those observed (0.01 to 2.2 percent) in irrigated agricultural basins in the Central Columbia Plateau of Washington State.

  3. Key Fish and Wildlife Species and Habitats in the Columbia River Basin Potentially Affected in a Cumulative Manner by Hydroelectric Development, 1985 Final Report.

    SciTech Connect

    Stull, Elizabeth Ann

    1985-09-30

    This final report summarizes the results of Task 1, which was the development of a list of key fish and wildlife species and habitat types that could potentially be impacted by hydroelectric development in a cumulative manner. Information developed in Task 1 is to be utilized in other tasks to identify specific pathways of cumulative effects, to assess current cumulative impact assessment methodologies, and to recommend alternative approaches for use in the Columbia River Basin. 58 refs., 17 tabs.

  4. The Western Ghat as the water tower of the South Indian Rivers : a stable isotope investigation on the origin of water and factors affecting the water cycle.

    NASA Astrophysics Data System (ADS)

    Lambs, Luc; Tripti, Muguli; Balakrishna, Keshava

    2014-05-01

    The long stretch (1600 km) of Ghats on the western side (Western Ghats) of Peninsular India separates relatively wetter west coast from drier eastern coast. The western and eastern sides of the Ghats are having distinct isotopic signatures indicating unequal distribution of the moisture sources. South India is characterized by having moisture source for southwest monsoon from Arabian Sea and northeast monsoon from Bay of Bengal. The wetter side of Peninsular region is covered by combination of evergreen tropical forest and grass lands, termed as Shola Forests which support higher vapor recycling process. Very few isotopic studies have been undertaken in these areas, except few places, mainly along the coast lines. This study presents the stable isotope results on rivers and groundwater of the Western Ghats covering Agumbe (Karnataka) to Ooty (Tamil Nadu) and its west coast river basins as observed for the three year period. The stable isotope results on the surface, subsurface and deep water pools show that the mean d18O value range from -4 o to -2 o on the west slope, and from -5 o to -4 o on the east slope, with quite no altitude or amount effect up to 2000 m asl. The more depleted values are found only in higher elevation, like the Doddabeta in the Nilgiri (2637m), with d18O close to -9 o which is exceptional for a tropical area. The hills on the west slope of the Western Ghats as well as in the mountainous Shola forest exhibit strong water vapor recycling as evidenced by high d-excess values. On the contrary on the eastern slope, the drier condition and the numerous impoundments and river damming support strong evaporation process. Thus, the study identifies the profound effect of tropical vegetation and anthropogenic factors on the recharge functioning of river and groundwater pools in Southern India.

  5. How does conversion of natural tropical rainforest ecosystems affect soil bacterial and fungal communities in the Nile river watershed of Uganda?

    PubMed

    Alele, Peter O; Sheil, Douglas; Surget-Groba, Yann; Lingling, Shi; Cannon, Charles H

    2014-01-01

    Uganda's forests are globally important for their conservation values but are under pressure from increasing human population and consumption. In this study, we examine how conversion of natural forest affects soil bacterial and fungal communities. Comparisons in paired natural forest and human-converted sites among four locations indicated that natural forest soils consistently had higher pH, organic carbon, nitrogen, and calcium, although variation among sites was large. Despite these differences, no effect on the diversity of dominant taxa for either bacterial or fungal communities was detected, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Composition of fungal communities did generally appear different in converted sites, but surprisingly, we did not observe a consistent pattern among sites. The spatial distribution of some taxa and community composition was associated with soil pH, organic carbon, phosphorus and sodium, suggesting that changes in soil communities were nuanced and require more robust metagenomic methods to understand the various components of the community. Given the close geographic proximity of the paired sampling sites, the similarity between natural and converted sites might be due to continued dispersal between treatments. Fungal communities showed greater environmental differentiation than bacterial communities, particularly according to soil pH. We detected biotic homogenization in converted ecosystems and substantial contribution of β-diversity to total diversity, indicating considerable geographic structure in soil biota in these forest communities. Overall, our results suggest that soil microbial communities are relatively resilient to forest conversion and despite a substantial and consistent change in the soil environment, the effects of conversion differed widely among sites. The substantial difference in soil chemistry, with generally lower nutrient quantity in converted sites, does bring

  6. How Does Conversion of Natural Tropical Rainforest Ecosystems Affect Soil Bacterial and Fungal Communities in the Nile River Watershed of Uganda?

    PubMed Central

    Alele, Peter O.; Sheil, Douglas; Surget-Groba, Yann; Lingling, Shi; Cannon, Charles H.

    2014-01-01

    Uganda's forests are globally important for their conservation values but are under pressure from increasing human population and consumption. In this study, we examine how conversion of natural forest affects soil bacterial and fungal communities. Comparisons in paired natural forest and human-converted sites among four locations indicated that natural forest soils consistently had higher pH, organic carbon, nitrogen, and calcium, although variation among sites was large. Despite these differences, no effect on the diversity of dominant taxa for either bacterial or fungal communities was detected, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Composition of fungal communities did generally appear different in converted sites, but surprisingly, we did not observe a consistent pattern among sites. The spatial distribution of some taxa and community composition was associated with soil pH, organic carbon, phosphorus and sodium, suggesting that changes in soil communities were nuanced and require more robust metagenomic methods to understand the various components of the community. Given the close geographic proximity of the paired sampling sites, the similarity between natural and converted sites might be due to continued dispersal between treatments. Fungal communities showed greater environmental differentiation than bacterial communities, particularly according to soil pH. We detected biotic homogenization in converted ecosystems and substantial contribution of β-diversity to total diversity, indicating considerable geographic structure in soil biota in these forest communities. Overall, our results suggest that soil microbial communities are relatively resilient to forest conversion and despite a substantial and consistent change in the soil environment, the effects of conversion differed widely among sites. The substantial difference in soil chemistry, with generally lower nutrient quantity in converted sites, does bring

  7. How does conversion of natural tropical rainforest ecosystems affect soil bacterial and fungal communities in the Nile river watershed of Uganda?

    PubMed

    Alele, Peter O; Sheil, Douglas; Surget-Groba, Yann; Lingling, Shi; Cannon, Charles H

    2014-01-01

    Uganda's forests are globally important for their conservation values but are under pressure from increasing human population and consumption. In this study, we examine how conversion of natural forest affects soil bacterial and fungal communities. Comparisons in paired natural forest and human-converted sites among four locations indicated that natural forest soils consistently had higher pH, organic carbon, nitrogen, and calcium, although variation among sites was large. Despite these differences, no effect on the diversity of dominant taxa for either bacterial or fungal communities was detected, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Composition of fungal communities did generally appear different in converted sites, but surprisingly, we did not observe a consistent pattern among sites. The spatial distribution of some taxa and community composition was associated with soil pH, organic carbon, phosphorus and sodium, suggesting that changes in soil communities were nuanced and require more robust metagenomic methods to understand the various components of the community. Given the close geographic proximity of the paired sampling sites, the similarity between natural and converted sites might be due to continued dispersal between treatments. Fungal communities showed greater environmental differentiation than bacterial communities, particularly according to soil pH. We detected biotic homogenization in converted ecosystems and substantial contribution of β-diversity to total diversity, indicating considerable geographic structure in soil biota in these forest communities. Overall, our results suggest that soil microbial communities are relatively resilient to forest conversion and despite a substantial and consistent change in the soil environment, the effects of conversion differed widely among sites. The substantial difference in soil chemistry, with generally lower nutrient quantity in converted sites, does bring

  8. Individual-based model of young-of-the-year striped bass population dynamics. II. Factors affecting recruitment in the Potomac River, Maryland

    SciTech Connect

    Cowan, J.H. ); Rose, K.A. ); Rutherford, E.S.; Houde, E.D. )

    1993-05-01

    An individual-based model of the population dynamics of young-of-the-year striped bass Morone saxatilis in the Potomac River, Maryland, was used to test the hypothesis that historically high recruitment variability can be explained by changes in environmental and biological factors that result in relatively small changes in growth and mortality rates of striped bass larvae. The four factors examined were (1) size distribution of female parents, (2) zooplankton prey density during the development of striped bass larvae, (3) density of completing larval white perch M. americana, and (4) temperature during larval development. Simulation results suggest that variations in female size and in prey for larvae alone could cause 10-fold variability in recruitment. But no single factor alone caused changes in vital rates of age-0 fish that could account for the 145-fold variability in the Potomac River index of juvenile recruitment. However, combined positive or negative effects of two or more factors resulted in more than a 150-fold simulated recruitment variability, suggesting that combinations of factors can account for the high observed annual variability in striped bass recruitment success. Higher cumulative mortality of feeding larvae and younger life stages than of juveniles was common to all simulations. supporting the contention that striped bass year-class strength is determined prior to metamorphosis. 76 refs., 7 figs., 4 tabs.

  9. Channel geometry and hydrologic data for six eruption-affected tributaries of the Lewis River, Mount St. Helens, Washington, water years 1983-84

    USGS Publications Warehouse

    Martinson, H.A.; Hammond, H.E.; Mast, W.W.; Mango, P.D.

    1986-01-01

    The May 18, 1980, eruption of Mount St. Helens generated a lateral blast, lahars, and tephra deposits that altered stream channels in the Lewis River drainage basin. In order to assess potential flood hazards, monitor channel adjustments, and construct a sediment budget for disturbed drainages on the east and southeast flanks of the volcano, channel cross sections were monumented and surveyed on Pine Creek, Muddy River, and Smith Creek during September and October of 1980. Additional cross sections were monumented and surveyed on Swift Creek, Bean Creek , and Clearwater Creek during 1981. This network of channel cross sections has been resurveyed annually. Selected cross sections have been surveyed more frequently, following periods of higher flow. Longitudinal stream profiles of the low-water thalweg and (or) water surfaces were surveyed periodically for selected short reaches of channel. Corresponding map views for these reaches were constructed using the survey data and aerial photographs. This report presents plots of channel cross-section profiles, longitudinal stream profiles, and channel maps constructed from survey data collected during water years 1983-84. (USGS)

  10. Perspective view of east face, looking due south, with train ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Perspective view of east face, looking due south, with train on bridge. - Pittsburgh, Fort Wayne & Chicago Railway, Beaver River Bridge, Spanning Beaver River along line of Second Avenue, New Brighton, Beaver County, PA

  11. Rivers as Political Boundaries: Peru and its Dynamic Borders

    NASA Astrophysics Data System (ADS)

    Abad, J. D.; Escobar, C.; Garcia, A. M. P.; Ortals, C.; Frias, C. E.; Vizcarra, J.

    2014-12-01

    Rivers, although inherently dynamic, have been chosen as political boundaries since the beginning of colonization for several reasons. Such divisions were chosen namely for their defensive capabilities and military benefits, and because they were often the first features mapped out by explorers. Furthermore, rivers were indisputable boundaries that did not require boundary pillars or people to guard them. However, it is important to understand the complexities of a river as a boundary. All rivers inevitably change over time through processes such as accretion, deposition, cut-off, or avulsion, rendering a political boundary subject to dispute. Depending upon the flow, size, and surrounding land, a river will migrate differently than others. As these natural features migrate one country loses land while another gains land leading to tension between legal rigidity and fluid dynamism. This in turn can manifest in social disruption due to cultural differences, political upheaval, or conflict risk as a result of scarce water resources. The purpose of this research is to assess the temporal and spatial variability of the political boundaries of Peru that follow rivers. Peru shares borders with Colombia, Brazil, Bolivia, Chile, and Ecuador. A large part of its northern border with Colombia follows the Putumayo River and later the Amazon River. Part of its eastern border with Brazil follows the Yavari River and later the Yaquirana River. These rivers are natural features used as political boundaries yet they differ in how each migrates. By means of a spatial and temporal analysis of satellite images it was possible to obtain erosion and deposition areas for the Putumayo River, the portion of the Amazon River that is part of the Peruvian boundary, the Yavari River, and the Yaquirana River. The erosion and deposition areas were related to land distribution among Peru, Colombia, and Brazil. By examining the Digital Elevation Model one can see how the altitude of the

  12. Techniques and equipment required for precise stream gaging in tide-affected fresh-water reaches of the Sacramento River, California

    USGS Publications Warehouse

    Smith, Winchell

    1971-01-01

    Current-meter measurements of high accuracy will be required for calibration of an acoustic flow-metering system proposed for installation in the Sacramento River at Chipps Island in California. This report presents an analysis of the problem of making continuous accurate current-meter measurements in this channel where the flow regime is changing constantly in response to tidal action. Gaging-system requirements are delineated, and a brief description is given of the several applicable techniques that have been developed by others. None of these techniques provides the accuracies required for the flowmeter calibration. A new system is described--one which has been assembled and tested in prototype and which will provide the matrix of data needed for accurate continuous current-meter measurements. Analysis of a large quantity of data on the velocity distribution in the channel of the Sacramento River at Chipps Island shows that adequate definition of the velocity can be made during the dominant flow periods--that is, at times other than slack-water periods--by use of current meters suspended at elevations 0.2 and 0.8 of the depth below the water surface. However, additional velocity surveys will be necessary to determine whether or not small systematic corrections need be applied during periods of rapidly changing flow. In the proposed system all gaged parameters, including velocities, depths, position in the stream, and related times, are monitored continuously as a boat moves across the river on the selected cross section. Data are recorded photographically and transferred later onto punchcards for computer processing. Computer programs have been written to permit computation of instantaneous discharges at any selected time interval throughout the period of the current meter measurement program. It is anticipated that current-meter traverses will be made at intervals of about one-half hour over periods of several days. Capability of performance for protracted

  13. Variation of dissolved organic carbon transported by two Chinese rivers: The Changjiang River and Yellow River.

    PubMed

    Liu, Dong; Pan, Delu; Bai, Yan; He, Xianqiang; Wang, Difeng; Zhang, Lin

    2015-11-15

    Real-time monitoring of riverine dissolved organic carbon (DOC) and the associated controlling factors is essential to coastal ocean management. This study was the first to simulate the monthly DOC concentrations at the Datong Hydrometric Station for the Changjiang River and at the Lijin Hydrometric Station for the Yellow River from 2000 to 2013 using a multilayer back-propagation neural network (MBPNN), along with basin remote-sensing products and river in situ data. The average absolute error between the modeled values and in situ values was 9.98% for the Changjiang River and 10.84% for the Yellow River. As an effect of water dilution, the variations of DOC concentrations in the two rivers were significantly negatively affected by discharge, with lower values reported during the wet season. Moreover, vegetation growth status and agricultural activities, represented by the gross primary product (GPP) and cropland area percent (CropPer) in the river basin, respectively, also significantly affected the DOC concentration in the Changjiang River, but not the Yellow River. The monthly riverine DOC flux was calculated using modeled DOC concentrations. In particular, the riverine DOC fluxes were affected by discharge, with 71.06% being reported for the Changjiang River and 90.71% for the Yellow River. Over the past decade, both DOC concentration and flux in the two rivers have not shown significant changes.

  14. Variation of dissolved organic carbon transported by two Chinese rivers: The Changjiang River and Yellow River.

    PubMed

    Liu, Dong; Pan, Delu; Bai, Yan; He, Xianqiang; Wang, Difeng; Zhang, Lin

    2015-11-15

    Real-time monitoring of riverine dissolved organic carbon (DOC) and the associated controlling factors is essential to coastal ocean management. This study was the first to simulate the monthly DOC concentrations at the Datong Hydrometric Station for the Changjiang River and at the Lijin Hydrometric Station for the Yellow River from 2000 to 2013 using a multilayer back-propagation neural network (MBPNN), along with basin remote-sensing products and river in situ data. The average absolute error between the modeled values and in situ values was 9.98% for the Changjiang River and 10.84% for the Yellow River. As an effect of water dilution, the variations of DOC concentrations in the two rivers were significantly negatively affected by discharge, with lower values reported during the wet season. Moreover, vegetation growth status and agricultural activities, represented by the gross primary product (GPP) and cropland area percent (CropPer) in the river basin, respectively, also significantly affected the DOC concentration in the Changjiang River, but not the Yellow River. The monthly riverine DOC flux was calculated using modeled DOC concentrations. In particular, the riverine DOC fluxes were affected by discharge, with 71.06% being reported for the Changjiang River and 90.71% for the Yellow River. Over the past decade, both DOC concentration and flux in the two rivers have not shown significant changes. PMID:26404069

  15. Human activities impact on mountain river channels (case study of Kamchatka peninsula rivers)

    NASA Astrophysics Data System (ADS)

    Ermakova, Aleksandra S.

    2010-05-01

    Human-induced driving factors along with natural environmental changes greatly impact on fluvial regime of rivers. On mountain and semi-mountain territories these processes are developed in the most complicated manner due to man-made activities diversity throughout river basins. Besides these processes are significantly enhanced because of the disastrous natural processes (like volcanic and mud-flow activity) frequent occurrences in mountainous regions. On of the most striking example on the matter is Kamchatka peninsula which is located at the North-West part of Russian Federation. This paper contributes to the study of human activities impact on fluvial systems in this volcanic mountain region. Human effects on rivers directly alter channel morphology and deformations, dynamics of water and sediment movement, aquatic communities or indirectly affect streams by altering the movement of water and sediment into the channel. In case study of Kamchatka peninsula human activities affect fluvial systems through engineering works including construction of bridges, dams and channel diversions and placer mining. These processes are characterized by spatial heterogeneity because of irregular population distribution. Due to specific natural conditions of the peninsula the most populated areas are the valleys of big rivers (rivers Kamchatka, Avacha, Bistraya (Bolshaya), etc) within piedmont and plain regions. These rivers are characterized by very unstable channels. Both with man-made activities this determines wide range of fluvial system changes. Firstly bridges construction leads to island and logjam formation directly near their piers and intensification of channels patterns shifts. Furthermore rivers of the peninsula are distinguished for high water flow velocities and water rate. Incorrect bridge constructions both with significant channel deformations lead to the destructions of the bridges themselves due to intensive bank erosion. Secondly, intensive water flow

  16. Comparison of the lipid properties of healthy and pansteatitis-affected African sharptooth catfish, Clarias gariepinus (Burchell), and the role of diet in pansteatitis outbreaks in the Olifants River in the Kruger National Park, South Africa.

    PubMed

    Huchzermeyer, K D A; Osthoff, G; Hugo, A; Govender, D

    2013-11-01

    Pansteatitis has been identified in wild populations of sharptooth catfish, Clarias gariepinus (Burchell), and Nile crocodiles, Crocodylus niloticus Laurenti, inhabiting the same waters in the Olifants River Gorge in the Kruger National Park, South Africa. Mesenteric and pectoral fat tissue was investigated microscopically and by fatty acid analysis in healthy and pansteatitis-affected catfish from both captive and wild populations. Variation in fatty acid composition between pectoral and mesenteric fat was noted. Composition of mesenteric fat differed between fish from various localities as a result of differences in diet. Pansteatitis in the captive population, resulting from ingestion of high amounts of dietary oxidized fat, reflected higher levels of unsaturated fatty acids within the mesenteric fat. Mesenteric fat of pansteatitis-affected wild catfish was characterized by an increase in moisture content, a decrease in fat content and a decrease in stearic and linoleic acids. The n-3 to n-6 fatty acid ratio of mesenteric fat was higher in pansteatitis-affected wild catfish than in healthy catfish from the same locality, reflecting higher polyunsaturated fat intake by pansteatitis-affected fish. The possible role of alien, invasive, phytoplankton-feeding silver carp, Hypophthalmichthys molitrix (Valenciennes), in the aetiology of pansteatitis in both catfish and crocodiles in the Olifants Gorge is discussed.

  17. Hydrogeochemical characteristics of the Tinto and Odiel Rivers (SW Spain). Factors controlling metal contents.

    PubMed

    Cánovas, C R; Olías, M; Nieto, J M; Sarmiento, A M; Cerón, J C

    2007-02-01

    The Tinto and Odiel Rivers are strongly affected by acid mine drainage (AMD) due to the intense sulphide mining developed in their basins over the past 5000 years. In this study the results obtained from a weekly sampling in both rivers, before their mouth in the Ría of Huelva, over three and a half years of control are analysed. In the Tinto River, the concentrations of sulphates, Al, Cd, Co, Li and Zn are double to those of the Odiel as a consequence of lower dilution. However, the concentration of Fe in the Odiel River is 20 times lower, since the precipitation of Fe oxyhydroxysulphates caused by neutralisation processes is more intense. Lower As, Cr, Cu and Pb concentrations are also found in the Odiel River as, to a greater or lesser extent, they are sorbed and/or coprecipitated with Fe. Other elements such as Be, Mn, Ni and Mg show similar values in both systems, which is ascribed to lithological factors. The seasonal evolution of contaminants is typical of rivers affected by AMD, reaching a maximum in autumn due to the dissolution of evaporitic salts precipitated during the summer. Nevertheless, in the Tinto River, Ca, Na and Sr show a strong increase during the summer, probably due to a greater water interaction with marly materials, through which the last reach of the river flows. Barium has a different behaviour from the rest of the metals and its concentration seems to be controlled by the solubility of barite. Iron, As and Pb show different behaviours in both rivers, those for Fe and As possibly linked to the prevalence of different dissolved species of Fe. The different Pb pattern is probably due to the control of Pb solubility by anglesite or other minerals rich in Pb in the Tinto River. PMID:17207846

  18. Dynamics of nitrifying bacterial communities in the Seine river and estuary as affected by changes in the treatment of Paris wastewater : a comparison of 2001-2003 vs 2012-2013 periods

    NASA Astrophysics Data System (ADS)

    Aissa Grouz, Najla; Billen, Gilles; Garnier, Josette; Mercier, Benjamin; Martinez, Anun

    2014-05-01

    The major branch of the Seine river from the confluence with the Marne river to the entrance of the estuary is deeply affected by the release of wastewater from the huge Paris agglomeration. In the first years of 2000, the largest part of the effluents were still discharged at the Seine-Aval (Achères) treatment plant with only a standard, low residence time, activated sludge treatment, thus releasing a high ammonium load. NH4 concentration as high as 7 mgN/l were frequently observed downstream from Paris agglomeration. Cébron et al. (2003, 2005) and Garnier et al. 2007 described in details how this massive reduced nitrogen concentrations triggered the growth of nitrifying bacteria, already present in the upstream Seine and Marne rivers, but also brought in large amount by the effluents of the wastewater treatment plant themselves. The decrease of ammonium concentration was slow, however, and was only completed 200 km downstream, in the upper estuarine area, where it causes a severe oxygen deficiency. Since 2007, important changes occurred in the treatment of nitrogen in the Parisian wastewater purification plants. In 2007, the Seine-Aval plant treated up to 90% of the ammonium contained in wastewater through nitrification, and 30% of the total supply of nitrates is treated by denitrification. These modifications have of course favorably affected the water quality of the Seine river: ammonium concentrations are reduced by a factor of 5 and the area of oxygen depletion in the upstream estuary is no more observed. However, nitrites, still released in the effluents, are a matter of concern for the water quality of the Seine downstream from Paris. Using measurements of potential microbial activities carried out with the same experimental protocol for the 2000-2003 and 2012-2013 periods, we here examine and model the dynamics of ammonium oxidizing and nitrite oxidizing microbial populations before and after the implementation of nitrification treatment of Paris

  19. Rapid river classification using GIS-delineated functional process zones

    EPA Science Inventory

    Traditional classification of rivers does not take into consideration how rivers function within the ecosystem. Using factors such as hydrology and geomorphology that directly affect ecosystem structure and function, provides a means of classifying river systems into hydrogeomorp...

  20. Hydrology of the Po River: looking for changing patterns in river discharge

    NASA Astrophysics Data System (ADS)

    Montanari, A.

    2012-05-01

    Scientists and public administrators are devoting increasing attention to the Po River, in Italy, in view of concerns related to the impact of increasing urbanisation and exploitation of water resources. A better understanding of the hydrological regime of the river is necessary to improve water resources management and flood protection. In particular, the analysis of the effects of hydrological and climatic change is crucial for planning sustainable development and economic growth. An extremely interesting issue is to inspect to what extent river flows can be naturally affected by the occurrence of long periods of water abundance or scarcity, which can be erroneously interpreted as irreversible changes due to human impact. In fact, drought and flood periods alternatively occurred in the recent past in the form of long term cycles. This paper presents advanced graphical and analytical methods to gain a better understanding of the temporal distribution of the Po River discharge. In particular, we present an analysis of river flow variability and memory properties to better understand natural patterns and in particular long term changes, which may affect the future flood risk and availability of water resources.

  1. [Health assessment of river ecosystem in Haihe River Basin, China].

    PubMed

    Hao, Li-Xia; Sun, Ran-Hao; Chen, Li-Ding

    2014-10-01

    With the development of economy, the health of river ecosystem is severely threatened because of the increasing effects of human activities on river ecosystem. In this paper, the authors assessed the river ecosystem health in aspects of chemical integrity and biological integrity, using the criterion in water quality, nutrient, and benthic macroinvertebrates of 73 samples in Haihe River Basin. The research showed that the health condition of river ecosystem in Haihe River Basin was bad overall since the health situation of 72. 6% of the samples was "extremely bad". At the same time, the health situation in Haihe River Basin exhibited obvious regional gathering effect. We also found that the river water quality was closely related to human activities, and the eutrophication trend of water body was evident in Haihe River Basin. The biodiversity of the benthic animal was low and lack of clean species in the basin. The indicators such as ammonia nitrogen, total nitrogen and total phosphorus were the key factors that affected the river ecosystem health in Haihe River Basin, so the government should start to curb the deterioration of river ecosystem health by controlling these nutrients indicators. For river ecosystem health assessment, the multi-factors comprehensive evaluation method was superior to single-factor method.

  2. Multi-scale Factors Affecting the Distribution of the Critically Imperiled Crayfish, Orconectes williamsi, in the Upper White River Drainage of Missouri, USA

    NASA Astrophysics Data System (ADS)

    Westhoff, J. T.; Distefano, R. J.; Guyot, J. A.; McManus, M. G.

    2005-05-01

    Orconectes williamsi is known from only a few locations in the upper White River drainage of Missouri and Arkansas. We implemented a stratified (by stream order) random survey to sample for this crayfish in Missouri in 2003-04. Survey objectives were twofold. First, we estimated the overall proportion of stream order segments (segments of streams between points where stream order changes) in the drainage harboring O. williamsi, and then estimated the proportion of first, second and third (or larger) order stream segments harboring this crayfish. Second, we obtained means or ratio estimators (point estimates) and 95 % confidence limits (interval estimates) for 62 environmental variables and conducted overall contrasts of those estimates between segments that did and did not harbor O. williamsi. For significant overall contrasts, we then conducted contrasts partitioned by stream order. We detected O. williamsi at an overall proportion of 0.34 of 50 sampled segments, with no difference between first and second order stream segments. Variables exhibiting differences between segments that did and did not harbor O. williamsi included bankfull width:bankfull depth ratio, wetted width:wetted depth ratio, macrophyte abundance, elevation, and stream connectivity. Results will be used to drive future sampling and conservation efforts.

  3. Heavy metals in waters and suspended sediments affected by a mine tailing spill in the upper San Lorenzo River, Northwestern México.

    PubMed

    Páez-Osuna, F; Bojórquez-Leyva, H; Bergés-Tiznado, M; Rubio-Hernández, O A; Fierro-Sañudo, J F; Ramírez-Rochín, J; León-Cañedo, J A

    2015-05-01

    Concentrations of arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), mercury (Hg), silver (Ag) and zinc (Zn) were evaluated in water and suspended sediments of the upper waters of San Lorenzo River in NW Mexico following a mine tailing spill. Except As (6.64-35.9 µg L(-1)), dissolved metal concentrations were low (Ag <0.06-0.22; Cd 0.01-0.34; Cu 4.71-10.2; Hg 0.02-0.24; Pb <0.15-0.65; Zn 86-1,080 µg L(-1)) and were less than the upper limits established by UNEP (Water quality for ecosystem and human health, 2nd edn. United Nations Environment Programme Global Environment Monitoring System/Water Programme, Burlington, 2008), EPA (2014) and the Mexican regulation (NOM 1994). In contrast, the suspended metal concentrations were high (As 91.4-130; Ag 22.1-531; Cd 3.14-6.30; Cu 65-123; Hg 0.47-1.09; Pb 260-818; Zn 742-1,810 mg kg(-1)) and most of samples exceeded the probable effect level of the Canadian Sediment Quality Guidelines for the Protection of Aquatic Life.

  4. Assessing bioavailability levels of metals in effluent-affected rivers: effect of Fe(III) and chelating agents on the distribution of metal speciation.

    PubMed

    Han, Shuping; Naito, Wataru; Masunaga, Shigeki

    2016-01-01

    To assess the effects of Fe(III) and anthropogenic ligands on the bioavailability of Ni, Cu, Zn, and Pb, concentrations of bioavailable metals were measured by the DGT (diffusive gradients in thin films) method in some urban rivers, and were compared with concentrations calculated by a chemical equilibrium model (WHAM 7.0). Assuming that dissolved Fe(III) (<0.45 μm membrane filtered) was in equilibrium with colloidal iron oxide, the WHAM 7.0 model estimated that bioavailable concentrations of Ni, Cu, and Zn were slightly higher than the corresponding values estimated assuming that dissolved Fe(III) was absent. In contrast, lower levels of free Pb were predicted by the WHAM 7.0 model when dissolved Fe(III) was included. Estimates showed that most of the dissolved Pb was present as colloidal iron-Pb complex. Ethylene-diamine-tetra-acetic acid (EDTA) concentrations at sampling sites were predicted from the relationship between EDTA and the calculated bioavailable concentration of Zn. When both colloidal iron and predicted EDTA concentrations were included in the WHAM 7.0 calculations, dissolved metals showed a strong tendency to form EDTA complexes, in the order Ni > Cu > Zn > Pb. With the inclusion of EDTA, bioavailable concentrations of Ni, Cu, and Zn predicted by WHAM 7.0 were different from those predicted considering only humic substances and colloidal iron. PMID:27533864

  5. Human impacts on river ice regime in the Carpathian Basin

    NASA Astrophysics Data System (ADS)

    Takács, Katalin; Nagy, Balázs; Kern, Zoltán

    2014-05-01

    examples from the Carpathian Basin represent some of the most common human impacts (engineering regulation, hydropower usage, water pollution), disturbing natural river ice regimes of mid-latitude rivers with densely populated or dynamically growing urban areas along their courses. In addition simple tests are also introduced to detect not only the climatic, but also the effect of anthropogenic impacts on river ice regime. As a result of river regulation on River Danube at Budapest a vanishing trend in river ice phenomena could be detected in the Danube records. The average ice-affected season shortened from 40 to 27 days, the average ice-covered season reduced greatly, from 27 to 7 days. In historical times the ice jams on the River Danube caused many times ice floods. The relative frequency of the break-up jam also decreased; moreover no ice flood occurred over the past 50 years. The changes due to hydropower usage are different upstream and downstream to the damming along the river. On Raba River upstream of the Nick dam at Ragyogóhíd, the ice-affected and ice-covered seasons were lengthened by 4 and 9 days, in contrast, downstream of the dam, the length of the ice-covered season was shortened by 7 days, and the number of ice-affected days decreased by 8 days at Árpás. During the observation period at Budapest on Danube River, the temperature requirements for river ice phenomena occurrence changed. Nowadays, much lower temperatures are needed to create the same ice phenomena compared to the start of the observations. For ice appearance, the mean winter air temperature requirements decreased from +2.39 °C to +1.71 °C. This investigation focused on anthropogenic effects on river ice regime, eliminating the impact of climatic conditions. Different forms of anthropogenic effects cause in most cases, a shorter length of ice-affected seasons and decreasing frequency of ice phenomena occurrence. Rising winter temperatures result the same changes in river ice regime

  6. Biotic interactions and sunlight affect persistence of fecal indicator bacteria and microbial source tracking genetic markers in the upper Mississippi river.

    PubMed

    Korajkic, Asja; McMinn, Brian R; Shanks, Orin C; Sivaganesan, Mano; Fout, G Shay; Ashbolt, Nicholas J

    2014-07-01

    The sanitary quality of recreational waters that may be impacted by sewage is assessed by enumerating fecal indicator bacteria (FIB) (Escherichia coli and enterococci); these organisms are found in the gastrointestinal tracts of humans and many other animals, and hence their presence provides no information about the pollution source. Microbial source tracking (MST) methods can discriminate between different pollution sources, providing critical information to water quality managers, but relatively little is known about factors influencing the decay of FIB and MST genetic markers following release into aquatic environments. An in situ mesocosm was deployed at a temperate recreational beach in the Mississippi River to evaluate the effects of ambient sunlight and biotic interactions (predation, competition, and viral lysis) on the decay of culture-based FIB, as well as molecularly based FIB (Entero1a and GenBac3) and human-associated MST genetic markers (HF183 and HumM2) measured by quantitative real-time PCR (qPCR). In general, culturable FIB decayed the fastest, while molecularly based FIB and human-associated genetic markers decayed more slowly. There was a strong correlation between the decay of molecularly based FIB and that of human-associated genetic markers (r(2), 0.96 to 0.98; P < 0.0001) but not between culturable FIB and any qPCR measurement. Overall, exposure to ambient sunlight may be an important factor in the early-stage decay dynamics but generally was not after continued exposure (i.e., after 120 h), when biotic interactions tended to be the only/major influential determinant of persistence. PMID:24747902

  7. Cadmium contamination of soil and crops is affected by intercropping and rotation systems in the lower reaches of the Minjiang River in south-western China.

    PubMed

    Liu, Yang; Liu, Kai; Li, Yong; Yang, Wanqin; Wu, Fuzhong; Zhu, Peng; Zhang, Jian; Chen, Lianghua; Gao, Shun; Zhang, Li

    2016-06-01

    Cadmium (Cd) accumulation and pollution in arable soils are particularly serious in the lower reaches of the Minjiang River in southwest of China. In this study, the remediation efficiency of Cd contamination in arable soils, the distribution pattern of Cd concentration in crops, and the food safety to humans of three typical cropping systems (S1: maize + sweet potato-Chinese cabbage, S2: maize + ginger-stem mustard, and S3: rice) were investigated and evaluated. After 1-year rotation, the percentage of Cd extracted by crops from the plough soil layer was observed in three system fields with the trend of S1 (2.30 %) > S2 (1.16 %) > S3 (0.21 %) and Cd extraction amount in crops was maximum in sweet potato, then in maize. The same kind of crop had the same pattern of Cd distribution in organs, and the edible parts generally accumulated less Cd amount than the inedible parts. Further, the grain crops were found to possibly be suitable one for using as phytoaccumulators of Cd contamination for farmlands. Direct consumption of these crops from the three systems would pose a high health risk to local inhabitants since it would result in the monthly intake of Cd (247 μg kg(-1) body weight) being nearly 10 times higher than the recommended tolerable monthly intake (RTMI) (25 μg kg(-1) body weight), resulting mainly from the consumption of vegetables rather than the grains, which would be potentially reduced by these foods being consumed by livestock firstly.

  8. Biotic Interactions and Sunlight Affect Persistence of Fecal Indicator Bacteria and Microbial Source Tracking Genetic Markers in the Upper Mississippi River

    PubMed Central

    McMinn, Brian R.; Shanks, Orin C.; Sivaganesan, Mano; Fout, G. Shay; Ashbolt, Nicholas J.

    2014-01-01

    The sanitary quality of recreational waters that may be impacted by sewage is assessed by enumerating fecal indicator bacteria (FIB) (Escherichia coli and enterococci); these organisms are found in the gastrointestinal tracts of humans and many other animals, and hence their presence provides no information about the pollution source. Microbial source tracking (MST) methods can discriminate between different pollution sources, providing critical information to water quality managers, but relatively little is known about factors influencing the decay of FIB and MST genetic markers following release into aquatic environments. An in situ mesocosm was deployed at a temperate recreational beach in the Mississippi River to evaluate the effects of ambient sunlight and biotic interactions (predation, competition, and viral lysis) on the decay of culture-based FIB, as well as molecularly based FIB (Entero1a and GenBac3) and human-associated MST genetic markers (HF183 and HumM2) measured by quantitative real-time PCR (qPCR). In general, culturable FIB decayed the fastest, while molecularly based FIB and human-associated genetic markers decayed more slowly. There was a strong correlation between the decay of molecularly based FIB and that of human-associated genetic markers (r2, 0.96 to 0.98; P < 0.0001) but not between culturable FIB and any qPCR measurement. Overall, exposure to ambient sunlight may be an important factor in the early-stage decay dynamics but generally was not after continued exposure (i.e., after 120 h), when biotic interactions tended to be the only/major influential determinant of persistence. PMID:24747902

  9. Cadmium contamination of soil and crops is affected by intercropping and rotation systems in the lower reaches of the Minjiang River in south-western China.

    PubMed

    Liu, Yang; Liu, Kai; Li, Yong; Yang, Wanqin; Wu, Fuzhong; Zhu, Peng; Zhang, Jian; Chen, Lianghua; Gao, Shun; Zhang, Li

    2016-06-01

    Cadmium (Cd) accumulation and pollution in arable soils are particularly serious in the lower reaches of the Minjiang River in southwest of China. In this study, the remediation efficiency of Cd contamination in arable soils, the distribution pattern of Cd concentration in crops, and the food safety to humans of three typical cropping systems (S1: maize + sweet potato-Chinese cabbage, S2: maize + ginger-stem mustard, and S3: rice) were investigated and evaluated. After 1-year rotation, the percentage of Cd extracted by crops from the plough soil layer was observed in three system fields with the trend of S1 (2.30 %) > S2 (1.16 %) > S3 (0.21 %) and Cd extraction amount in crops was maximum in sweet potato, then in maize. The same kind of crop had the same pattern of Cd distribution in organs, and the edible parts generally accumulated less Cd amount than the inedible parts. Further, the grain crops were found to possibly be suitable one for using as phytoaccumulators of Cd contamination for farmlands. Direct consumption of these crops from the three systems would pose a high health risk to local inhabitants since it would result in the monthly intake of Cd (247 μg kg(-1) body weight) being nearly 10 times higher than the recommended tolerable monthly intake (RTMI) (25 μg kg(-1) body weight), resulting mainly from the consumption of vegetables rather than the grains, which would be potentially reduced by these foods being consumed by livestock firstly. PMID:26323960

  10. Landscape characteristics affecting streams in urbanizing regions of the Delaware River Basin (New Jersey, New York, and Pennsylvania, U.S.)

    USGS Publications Warehouse

    Riva-Murray, K.; Riemann, R.; Murdoch, P.; Fischer, J.M.; Brightbill, R.

    2010-01-01

    Widespread and increasing urbanization has resulted in the need to assess, monitor, and understand its effects on stream water quality. Identifying relations between stream ecological condition and urban intensity indicators such as impervious surface provides important, but insufficient information to effectively address planning and management needs in such areas. In this study we investigate those specific landscape metrics which are functionally linked to indicators of stream ecological condition, and in particular, identify those characteristics that exacerbate or mitigate changes in ecological condition over and above impervious surface. The approach used addresses challenges associated with redundancy of landscape metrics, and links landscape pattern and composition to an indicator of stream ecological condition across a broad area of the eastern United States. Macroinvertebrate samples were collected during 2000-2001 from forty-two sites in the Delaware River Basin, and landscape data of high spatial and thematic resolution were obtained from photointerpretation of 1999 imagery. An ordination-derived 'biotic score' was positively correlated with assemblage tolerance, and with urban-related chemical characteristics such as chloride concentration and an index of potential pesticide toxicity. Impervious surface explained 56% of the variation in biotic score, but the variation explained increased to as high as 83% with the incorporation of a second land use, cover, or configuration metric at catchment or riparian scales. These include land use class-specific cover metrics such as percent of urban land with tree cover, forest fragmentation metrics such as aggregation index, riparian metrics such as percent tree cover, and metrics related to urban aggregation. Study results indicate that these metrics will be important to monitor in urbanizing areas in addition to impervious surface. ?? 2010 US Government.

  11. ALPHA ATTENUATION DUE TO DUST LOADING

    SciTech Connect

    Dailey, A; Dennis Hadlock, D

    2007-08-09

    Previous studies had been done in order to show the attenuation of alpha particles in filter media. These studies provided an accurate correction for this attenuation, but there had not yet been a study with sufficient results to properly correct for attenuation due to dust loading on the filters. At the Savannah River Site, filter samples are corrected for attenuation due to dust loading at 20%. Depending on the facility the filter comes from and the duration of the sampling period, the proper correction factor may vary. The objective of this study was to determine self-absorption curves for each of three counting instruments. Prior work indicated significant decreases in alpha count rate (as much as 38%) due to dust loading, especially on filters from facilities where sampling takes place over long intervals. The alpha count rate decreased because of a decrease in the energy of the alpha. The study performed resulted in a set of alpha absorption curves for each of three detectors. This study also took into account the affects of the geometry differences in the different counting equipment used.

  12. THE CONFIGURATION AND THE FORMING PROCESS OF RIVER CHANNEL INFLUENCED BY RIVER CROSSING STRUCTURES AND GRAVEL MINING

    NASA Astrophysics Data System (ADS)

    Harada, Daisuke; Chibana, Takeyoshi; Yamashita, Kimiko

    In many Japanese gravel-bed rivers, during these 30 years, river morphology has changed from single channel to compound channel, and the black locust has been rapidly spreading its habitat in the flood channel. It is said that this change has been caused by past gravel mining and the construction of river-crossing structures. This study aims to reveal how these human impacts affected and altered the river configuration. Previous study pointed out that theriver slope is determined by the size of sediment and the flow condition. In the Tama River, however, it was pointed out that the loss of cobbles and boulders due to gravel mining made the riverbed slope in low flow channel milder than before and formed compound channel. The low flow channel width was narrowest just downstream of a river-crossing structure but increased in the flow direction and was largest upstream of the next structure. This situation was also seen in other gravel-bed rivers, and its ecosystem was strongly related to the height of the weir and the length between a structure and a structure. In the upstream area of the alluvial fan of the Tama river, in 1968, when gravel mining had finished, bedrock was exposed in a lot of places due to gravel mining. This bedrock was firstly eroded just downstream of each structure, and the erosion progressed in the flow direction. This erosion formed low flow channel, and in its flood channel, the suitable condition for the black locust, which was revealed in this paper, was formed during several heavy floods and caused sudden expansion of blacklocust. On the other hand, from the upstream of the next structure, deposited sediment has formed gravel-bed river toward upstream direction. As a result, boundary of eroded channel and gravel-bed channel was formed between the structures.

  13. Evolution of river dolphins.

    PubMed Central

    Hamilton, H.; Caballero, S.; Collins, A. G.; Brownell, R. L.

    2001-01-01

    The world's river dolphins (Inia, Pontoporia, Lipotes and Platanista) are among the least known and most endangered of all cetaceans. The four extant genera inhabit geographically disjunct river systems and exhibit highly modified morphologies, leading many cetologists to regard river dolphins as an unnatural group. Numerous arrangements have been proposed for their phylogenetic relationships to one another and to other odontocete cetaceans. These alternative views strongly affect the biogeographical and evolutionary implications raised by the important, although limited, fossil record of river dolphins. We present a hypothesis of river dolphin relationships based on phylogenetic analysis of three mitochondrial genes for 29 cetacean species, concluding that the four genera represent three separate, ancient branches in odontocete evolution. Our molecular phylogeny corresponds well with the first fossil appearances of the primary lineages of modern odontocetes. Integrating relevant events in Tertiary palaeoceanography, we develop a scenario for river dolphin evolution during the globally high sea levels of the Middle Miocene. We suggest that ancestors of the four extant river dolphin lineages colonized the shallow epicontintental seas that inundated the Amazon, Paraná, Yangtze and Indo-Gangetic river basins, subsequently remaining in these extensive waterways during their transition to freshwater with the Late Neogene trend of sea-level lowering. PMID:11296868

  14. Factors affecting the occurrence of Escherichia coli O157 contamination in irrigation ponds on produce farms in the Suwannee River Watershed.

    PubMed

    Gu, Ganyu; Luo, Zhiyao; Cevallos-Cevallos, Juan M; Adams, Paige; Vellidis, George; Wright, Anita; van Bruggen, Ariena H C

    2013-03-01

    Outbreaks of enteritis caused by Escherichia coli O157 associated with fresh produce have resulted in questions about the safety of irrigation water; however, associated risks have not been systematically evaluated. In this study, the occurrence and distribution of the human pathogen E. coli O157 from vegetable irrigation ponds within the Suwannee River Watershed in Georgia were investigated, and the relationship to environmental factors was analyzed. Surface and subsurface water samples were collected monthly from 10 vegetable irrigation ponds from March 2011 to February 2012. Escherichia coli O157 was isolated from enriched filtrates on CHROMagar and sorbitol MacConkey agar media and confirmed by an agglutination test. Presence of virulence genes stx1, stx2 , and eae was tested by polymerase chain reaction. In addition, 27 environmental variables of the sampled ponds were measured. Denaturing gradient gel electrophoresis was conducted for the analysis of bacterial communities in the water samples. Biserial correlation coefficients were calculated to evaluate the log10 colony-forming unit per millilitre correlations between the environmental factors and the occurrence of E. coli O157. Stepwise and canonical discriminant analyses were used to determine the factors that were associated with the presence and absence of E. coli O157 in water samples. All 10 ponds were positive for E. coli O157 some of the time, mainly in summer and fall of 2011. The temporal distribution of this bacterium differed among the 10 ponds. Temperature, rainfall, populations of fecal coliform, and culturable bacteria were positively correlated with the occurrence of E. coli O157 (P < 0.05), while the total nitrogen concentration, oxidation-reduction potential, and dissolved oxygen concentration were negatively correlated with the occurrence of this pathogen (P < 0.05). Temperature and rainfall were the most important factors contributing to the discrimination between samples with and without

  15. Impact of heatwaves on river water temperature in Switzerland

    NASA Astrophysics Data System (ADS)

    Siviglia, Annunziato; Piccolroaz, Sebastiano; Toffolon, Marco

    2015-04-01

    Air temperature records show that multi-day heatwaves are becoming more frequent in Europe during summer months. Future projections depict scenarios in which this trend could be even more probable, likely bringing to severe impacts on human, economic, and natural environment. In this work, we analyse the correlation between daily averaged anomalies of air temperature and river water temperature considering a database of 15 Swiss rivers covering a period of 30 years (1984-2013). We find that the response of the natural rivers is strongly correlated with air temperature, while anthropogenic impacted rivers affected by hydro- and thermo-peaking (due to hypolimnetic release of water from reservoirs) tend to show a null or very mild dependence, especially during summer months. In all cases, the response is approximately linear, thus allowing for a clear distinction between the two types of rivers on the basis of the proportionality coefficient. We specifically focus on the two most intense heatwaves (June-August 2003 and July 2006) that produced severe effects in the European Alpine region, and show that the alteration of the river thermal behaviour due to hydropower production may mitigate the effects of these extreme events.

  16. Hydro-geomorphic Modeling of the Impacts of Dam Removal on Ecosystem Services on the White Salmon River, WA

    NASA Astrophysics Data System (ADS)

    Bunn, J. T.

    2010-12-01

    By agreement between PacifiCorp and the Federal Energy Regulatory Commission, Condit Dam on the White Salmon River in Washington State is slated to be removed in 2011, to restore anadromous salmon habitat. Our study predicts changes in hydraulics and sedimentation from dam removal on the White Salmon River in order to assess the significance of such changes to ecosystem services provided by the river. We analyzed river users’ focus-group surveys to identify relationships between physical features of the river and ecosystem services valued by users of the White Salmon River. We used HEC-RAS and numeric solutions of sediment transport morphodynamics to predict changes to water velocity, criticality of flow, water surface width, water depth, and sediment balance at various points along the river for current conditions and for after the dam has been removed and river dynamics have stabilized. Our results indicate that several identified services are likely to be affected by hydraulic changes or sedimentation after dam removal. In general, our models suggest that the river will have more whitewater, the greater part of re-exposed river channel will be bedrock, water surface width will narrow in high demand recreation areas, and sediment is likely to accumulate significantly at the river mouth. Our analysis of use by members of the focus group suggests that the experience of whitewater boaters (kayakers in particular) is likely to be enhanced, but that general leisure and fishing uses may be impaired due to decreased accessibility.

  17. Processes affecting δ34S and δ18O values of dissolved sulfate in alluvium along the Canadian River, central Oklahoma, USA

    USGS Publications Warehouse

    Tuttle, Michele L.W.; Breit, George N.; Cozzarelli, Isabelle M.

    2009-01-01

    The δ34S and δ18O values for dissolved sulfate in groundwater are commonly used in aquifer studies to identify sulfate reservoirs and describe biogeochemical processes. The utility of these data, however, often is compromised by mixing of sulfate sources within reservoirs and isotope fractionation during sulfur redox cycling. Our study shows that, after all potential sulfate sources are identified and isotopically characterized, the δ34SSO4 and δ18OSO4 values differentiate processes such as sulfate-source mixing, sulfide oxidation, barite dissolution, and organosulfur decomposition. During bacterial reduction of sulfate, the values reflect kinetic sulfur isotope fractionation and exchange of oxygen isotopes between sulfate and water. Detailed analysis of the chemistry (Cl and SO4 concentrations) and isotopic composition (δ2HH2Oand δ18OH2O) of groundwater in an alluvial aquifer in Central Oklahoma, USA allowed the identification of five distinct end members that supply water to the aquifer (regional groundwater flowing into the study area, river water, leachate from a closed landfill that operated within the site, rain, and surface runoff). The δ34SSO4 and δ18OSO4 values in each end member differentiated three sources of sulfate: sulfate dissolved from Early to Late Permian rocks within the drainage basin (δ34SSO4 = 8–12‰ and δ18OSO4 = 10‰), iron sulfides oxidized by molecular oxygen during low water-table levels (δ34SSO4 = − 16‰ and δ18OSO4 = 10‰), and organosulfur compounds (predominately ester sulfates) from decomposition of vegetation on the surface and from landfill trash buried in the alluvium (δ34SSO4 = 8‰ and δ18OSO4 = 6‰). During bacterial reduction of these sulfate sources, similar isotope fractionation processes are recorded in the parallel trends of increasing δ34SSO4 and δ18OSO4 values. When extensive reduction occurs, the kinetic sulfur isotope fractionation (estimated by εH2S–SO4 = − 23

  18. Water resource management in river oases along the Tarim River in North-West of China

    NASA Astrophysics Data System (ADS)

    Kliucininkaite, Lina; Disse, Markus

    2013-04-01

    Tarim River is one of the longest inland rivers in the world. It flows its water in the northern part of the Taklamakan desert in Xinjiang, North-west of China, which is a very hostile region due its climatic conditions and particularly due to low precipitation and very high evaporation rates. During the past five decades intensive exploitation of water resources, mainly by agricultural activities, has changed the temporal and spatial distribution of them and caused serious environmental problems in the Tarim River Basin. The support measures for oasis management along the Tarim River under climatic and societal changes became the overarching goal of this research. The temperature has risen by nearly 1° C over the past 50 years in the Tarim River Basin so more water was available in the mountainous areas of Xinjiang, leading to an increasing trend of the headstream discharges of the Tarim Basin. Aksu, Hotan and Yarkant Rivers are three tributaries of the Tarim River, as well as its main water suppliers. However, under the condition of water increase with the volume of 25×108 m3 in headstreams in recent 10 years, the water to the mainstream has increased less than 108 m3 (in Alar hydrological station), which is less than 3% of the increased water volume of runoff. Moreover, the region is one of the biggest cotton and other cash crops producers in China. In addition, expansion of urban and, in particular, of irrigation areas have caused higher water consumption at different parts of the river, leading to severe ecological effects on rural areas, especially in the lower reaches. Moreover, it also highly affects groundwater level and quality. The aim of this research is to support decision makers, planners and engineers to find right measures in the area for the further development of the region, as well as adaptation to changing climate. Different scenarios for water resource management, as well as water distribution and allocation in a more efficient and water

  19. Sediment dynamics within the intertidal floodplain of the lower Amazon River

    NASA Astrophysics Data System (ADS)

    Fricke, A. T.; Nittrouer, C. A.; Ogston, A. S.; Nowacki, D. J.; Asp, N. E.; Souza Filho, P. W.

    2014-12-01

    Tidal influence extends ~800 kilometers upstream of the Amazon River mouth, producing semidiurnal oscillations in water elevation and slowing or reversing the flow of the world's largest river. This tidally influenced reach, known as the tidal river, is flanked by an expansive intertidal floodplain, and includes confluences with two large tributaries, the Xingu and Tapajós. The relative magnitude of the seasonal and tidal signals changes along the length of the tidal river, yielding diverse floodplain environments that span a range of seasonal and tidal influence. Near the upstream limit of tides, natural levees isolate the river from the floodplain during low to moderate flows, while in the lower tidal river, natural levees are absent and river-floodplain exchange is dominated by the tides rather than seasonal variation in river stage. This difference between fluvial and tidal systems strongly affects the nature of sediment exchange between the channel and floodplain, including frequency, duration, and depth of inundation. Here we present data on the impact of this fluvial-tidal continuum on sedimentary processes in the floodplain and resultant depositional signatures. Changes in levee prominence, grain size, and sediment accumulation combine to produce the distinct morphologies of floodplain lakes, intertidal backswamps, and intertidal flats. In addition to sediment accumulation on the periodically exposed floodplain, Amazon River sediment accumulates within the drowned tributary confluences of the Xingu and Tapajós Rivers. Here seasonal and tidal changes in water temperature, discharge, and suspended-sediment concentration drive barotropic and baroclinic flows that transport Amazon River sediment into tributary basins. These findings help to constrain the fate of sediment within the ungauged Amazon tidal river, and will help in understanding the response of the lower Amazon River to changes in accommodation space associated with rising sea level, and changes

  20. River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons.

    PubMed

    Corsi, Steven R; De Cicco, Laura A; Lutz, Michelle A; Hirsch, Robert M

    2015-03-01

    Chloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49 years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230 mg/L by an average of more than 100 individual days per year during 2006-2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period. PMID:25514764

  1. River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons.

    PubMed

    Corsi, Steven R; De Cicco, Laura A; Lutz, Michelle A; Hirsch, Robert M

    2015-03-01

    Chloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49 years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230 mg/L by an average of more than 100 individual days per year during 2006-2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period.

  2. River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons

    USGS Publications Warehouse

    Corsi, Steven R.; DeCicco, Laura A.; Lutz, Michelle A.; Hirsch, Robert M.

    2014-01-01

    Chloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49 years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230 mg/L by an average of more than 100 individual days per year during 2006–2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period.

  3. Residential Preferences for River Network Improvement: An Exploration of Choice Experiments in Zhujiajiao, Shanghai, China

    NASA Astrophysics Data System (ADS)

    Che, Yue; Li, Wen; Shang, Zhaoyi; Liu, Chen; Yang, Kai

    2014-09-01

    River networks have both ecological and social benefits for urban development. However, river networks have suffered extensive destruction as a result of urbanization and industrialization, especially in China. River restoration is a growth business but suffers poor efficiency due to a lack of social understanding. Assessing the benefits of river system restoration and recognizing public preferences are critical for effective river ecosystem restoration and sustainable river management. This study used a choice experiment with a multinomial logit model and a random parameter logit model to assess respondents' cognitive preferences regarding attributes of river networks, and their possible sources of heterogeneity. Results showed that riverfront condition was the attribute most preferred by respondents, while stream morphology was the least preferred. Results also illustrated that the current status of each of three river network attributes was not desirable, and respondents would prefer a river network with a "branch pattern," that is "limpid with no odor," and "accessible with vegetation." Estimated willingness to pay was mainly affected by household monthly income, residential location, and whether respondents had household members engaged in a water protection career. The assessment results can provide guidance and a reference for managers, sponsors, and researchers.

  4. An approach for assessing cumulative effects in a model river, the Athabasca River basin.

    PubMed

    Squires, Allison J; Westbrook, Cherie J; Dubé, Monique G

    2010-01-01

    Novel approaches addressing aquatic cumulative effects over broad temporal and spatial scales are required to track changes and assist with sustainable watershed management. Cumulative effects assessment (CEA) requires the assessment of changes due to multiple stressors both spatially and temporally. The province of Alberta, Canada, is currently experiencing significant economic growth as well as increasing awareness of water dependencies. There has been an increasing level of industrial, urban, and other land-use related development (pulp and paper mills, oil sands developments, agriculture, and urban development) within the Athabasca River basin. Much of the historical water quantity and quality data for this basin have not been integrated or analyzed from headwaters to mouth, which affects development of a holistic, watershed-scale CEA. The main objectives of this study were 1) to quantify spatial and temporal changes in water quantity and quality over the entire Athabasca River mainstem across historical (1966–1976) and current day (1996–2006) time periods and 2) to evaluate the significance of any changes relative to existing benchmarks (e.g., water quality guidelines). Data were collected from several federal, provincial, and nongovernment sources. A 14% to 30% decrease in discharge was observed during the low flow period in the second time period in the lower 3 river reaches with the greatest decrease occurring at the mouth of the river. Dissolved Na, sulfate, chloride, and total P concentrations in the second time period were greater than, and in some cases double, the 90th percentiles calculated from the first time period in the lower part of the river. Our results show that significant changes have occurred in both water quantity and quality between the historical and current day Athabasca River basin. It is known that, in addition to climatic changes, rivers which undergo increased agricultural, urban, and industrial development can experience

  5. The evolution of the Shiwanghe River valley in response to the Yellow River incision in the Hukou area, Shaanxi, China

    NASA Astrophysics Data System (ADS)

    Qiu, Wei-Li; Zhang, Jia-Fu; Wang, Xiao-Yan; Guo, Yu-Jie; Zhuang, Mao-Guo; Fu, Xiao; Zhou, Li-Ping

    2014-06-01

    Tributary response to mainstream incision is an important landscape evolution process. The objective of this study is to examine tributary valley evolution in response to mainstream incision. The Shiwanghe River, a tributary of the Yellow River in the Hukou area, was chosen for a case study. The terraces and knickpoints of the Shiwanghe River were investigated and correlated to those of the mainstream. Optically stimulated luminescence (OSL) was applied to date fluvial terraces. Longitudinal profiles of river and terraces were used to analyze valley evolution. The terrace sequence of the Shiwanghe River near their confluence is almost identical to the Yellow River terraces at the Hukou area. This suggests that terrace formations of the tributary and the mainstream are synchronous, and influenced by similar factors. But the formation age of the same tributary terrace varies from downstream to the upper reaches of the river valley. For such terraces, their formation should be controlled by knickpoint migration. A sudden drop in base-level caused by the Yellow River incision would trigger the formation of a knickpoint in the tributary. A new terrace would be formed as the knickpoint propagated upstream throughout the tributary valley. Due to the different erodibility of bedrock, a set of interbedded sandstone and shale, the major knickpoint would disassemble into a cluster of small ones during its propagation. The age of terrace formation with various valley segments depends on knickpoint migration rate and distance from the confluence. Vertical incision of the Yellow River results in knickpoint recession of its tributaries. The migration rate of knickpoints was affected by climate, lithologic variation, and, to some extent, structural control.

  6. Impact of dam construction on river banks evolution and sediment dynamics. A case study from the Po River (Italy).

    NASA Astrophysics Data System (ADS)

    Maselli, V.; Pellegrini, C.; Crose, L.; Del Bianco, F.; Mercorella, A.

    2014-12-01

    Rivers draining densely populated landscapes are extremely impacted by modern human engineering: armored beds, artificial levees and dams modified natural fluvial dynamics, and consequently, the evolution of alluvial plains, deltas and coastal environments. Dams, in particular, segmented the longitudinal continuity of the river and reduced (or even interrupted) the export of sediment toward the sea. Here we investigate the impact of the Isola Serafini dam on the upstream portion of the Po River (Italy) influenced by backwater, by using an integrated approach of aerial and satellite images, longitudinal cross-sections, grain size analysis, backscatter data and multibeam bathymetry. The analysis of aerial photographs, acquired every 10 yr since the dam construction in 1960, and of longitudinal cross-sections, allows understanding how the river adjusts its profile in response to the backwater and quantifying areas of net river banks erosion and deposition in meanders. The drowning of the reaches influenced by backwater reduced the progradation of point bars and promoted the deposition of fine grained sediments, as highlighted by grain size analysis on surficial sediment sampled across and along the river course. Calibrated back-scatter data with grain-size distributions of two selected meanders, under the backwater effect and beyond, show how sands are progressively replaced by fine-grained sediments in the meander belt and in the river axis, mainly reflecting the reduction of flow velocity, inferred also by river bed roughness. The understanding of river and sediment dynamics under the influence of backwater due to dam construction is useful when studying pristine systems in which natural backwater affects their evolution, as in the case of the formation of standing water bodies during the drowning of an incised valley.

  7. Critical pollution levels in Umguza River, Zimbabwe

    NASA Astrophysics Data System (ADS)

    Chinyama, A.; Ncube, R.; Ela, W.

    2016-06-01

    In most countries worldwide regulatory bodies set effluent discharge limits into rivers and other natural water bodies. These limits specify the maximum permissible concentration of defined pollutants that may be discharged into the water body. This limit is conceptually based on the self-purification (assimilative) capacity of the receiving water. However, this self-purification constant is itself a function of the water's pollutant loading. Umguza River situated south west of Zimbabwe, is fed by tributaries that drain an urban catchment and as such is prone to pollution due to human activities in the catchment. This study investigated the levels of pollution in Umguza River that would affect its self-purification capacity. This was achieved by characterising the spatial distribution of a selected range of water quality parameters as well as determining the self-purification capacity of a stretch of the river. Critical pollutant concentrations were determined for some of the parameters that showed high values along the stretch. The selected parameters of interest were dissolved oxygen, suspended solids, phosphates, nitrates, COD, turbidity, ammonia, pH, alkalinity and temperature. The study was carried out from January 2014 to April 2014. The self-purification capacity was determined using a formula that compares the mass flux of a pollutant upstream and downstream of the selected stretch of the river. Statistical analysis was used to establish relationships between the pollutants and the self-purification capacity of the river. The study found that the levels of ammonia and phosphates were very high compared to the regulated limits (2 mg/l vs 0.5 mg/l; and 8 mg/l vs 0.5 mg/l respectively). It was also found that the self-purification capacity varied significantly across pollutants. It was therefore concluded that a critical pollutant concentration exists above which the river completely loses its natural ability to assimilate and decrease its pollutant load over

  8. Water temperature controls in low arctic rivers

    NASA Astrophysics Data System (ADS)

    King, Tyler V.; Neilson, Bethany T.; Overbeck, Levi D.; Kane, Douglas L.

    2016-06-01

    Understanding the dynamics of heat transfer mechanisms is critical for forecasting the effects of climate change on arctic river temperatures. Climate influences on arctic river temperatures can be particularly important due to corresponding effects on nutrient dynamics and ecological responses. It was hypothesized that the same heat and mass fluxes affect arctic and temperate rivers, but that relative importance and variability over time and space differ. Through data collection and application of a river temperature model that accounts for the primary heat fluxes relevant in temperate climates, heat fluxes were estimated for a large arctic basin over wide ranges of hydrologic conditions. Heat flux influences similar to temperate systems included dominant shortwave radiation, shifts from positive to negative sensible heat flux with distance downstream, and greater influences of lateral inflows in the headwater region. Heat fluxes that differed from many temperate systems included consistently negative net longwave radiation and small average latent heat fluxes. Radiative heat fluxes comprised 88% of total absolute heat flux while all other heat fluxes contributed less than 5% on average. Periodic significance was seen for lateral inflows (up to 26%) and latent heat flux (up to 18%) in the lower and higher stream order portions of the watershed, respectively. Evenly distributed lateral inflows from large scale flow differencing and temperatures from representative tributaries provided a data efficient method for estimating the associated heat loads. Poor model performance under low flows demonstrated need for further testing and data collection to support the inclusion of additional heat fluxes.

  9. Natural and anthropogenic factors controlling the dissolved organic carbon concentrations and fluxes in a large tropical river, India.

    PubMed

    Balakrishna, K; Kumar, Itta Arun; Srinikethan, G; Mugeraya, Gopal

    2006-11-01

    Carbon studies in tropical rivers have gained significance since it was realized that a significant chunk of anthropogenic CO(2) emitted into the atmosphere returns to the biosphere, that is eventually transported by the river and locked up in coastal sediments for a few thousand years. Carbon studies are also significant because dissolved organic carbon (DOC) is known to complex the toxic trace metals in the river and carry them in the dissolved form. For the first time, this work has made an attempt to study the variations in DOC concentrations in space and time for a period of 19 months, and estimate their fluxes in the largest peninsular Indian river, the Godavari at Rajahmundry. Anthropogenic influence on DOC concentrations possibly from the number of bathing ghats along the banks and domestic sewage discharge into the river are evident during the pre-monsoon of 2004 and 2005. The rise in DOC concentrations at the onset of monsoon could be due to the contributions from flood plains and soils from the river catchment. Spatial variations highlighted that the DOC concentrations in the river are affected more by the anthropogenic discharges in the downstream than in the upstream. The discharge weighted DOC concentrations in the Godavari river is 3-12 times lower than Ganga-Brahmaputra, Indus and major Chinese rivers. The total carbon fluxes from the Godavari into the Bay of Bengal is insignificant (0.5%) compared to the total carbon discharges by major rivers of the world into oceans.

  10. Long-term natural remediation process in textile dye-polluted river sediment driven by bacterial community changes.

    PubMed

    Ito, Tsukasa; Adachi, Yusuke; Yamanashi, Yu; Shimada, Yosuke

    2016-09-01

    The textile and dyeing industries are major sources of environmental water pollution all over the world. The textile wastewater effluents discharged into rivers often appear dark red-purple in color due to azo dyes, which can be transformed into carcinogenic aromatic amines. The chemicals used in dyeing are not readily degraded in nature and thus precipitate in river sediment. However, little is known about how dyeing chemicals affect river sediment and river water or how long they persist because they are difficult to monitor. To assess undetectable dyes and byproducts in river sediments, we evaluated the potential of river sediment bacteria to degrade dyes and aromatic amines. We describe the natural remediation of river sediment long-contaminated by textile dyeing effluent. After cessation of wastewater discharge, the dye-degradation potential decreased, and the aromatic amine-degradation potential increased initially and then declined over time. The changes in degradation potential were consistent with changes in the sediment bacterial community. The transition occurred on the order of years. Our data strongly suggest that dyes remained in the river sediment and that aromatic amines were produced even in transparent- and no longer colored-river water, but these chemicals were degraded by the changing sediment bacteria. Time-course monitoring of the degradation activities of key bacteria thus enables assessment of the fate of dye pollutants in river sediments.

  11. Long-term natural remediation process in textile dye-polluted river sediment driven by bacterial community changes.

    PubMed

    Ito, Tsukasa; Adachi, Yusuke; Yamanashi, Yu; Shimada, Yosuke

    2016-09-01

    The textile and dyeing industries are major sources of environmental water pollution all over the world. The textile wastewater effluents discharged into rivers often appear dark red-purple in color due to azo dyes, which can be transformed into carcinogenic aromatic amines. The chemicals used in dyeing are not readily degraded in nature and thus precipitate in river sediment. However, little is known about how dyeing chemicals affect river sediment and river water or how long they persist because they are difficult to monitor. To assess undetectable dyes and byproducts in river sediments, we evaluated the potential of river sediment bacteria to degrade dyes and aromatic amines. We describe the natural remediation of river sediment long-contaminated by textile dyeing effluent. After cessation of wastewater discharge, the dye-degradation potential decreased, and the aromatic amine-degradation potential increased initially and then declined over time. The changes in degradation potential were consistent with changes in the sediment bacterial community. The transition occurred on the order of years. Our data strongly suggest that dyes remained in the river sediment and that aromatic amines were produced even in transparent- and no longer colored-river water, but these chemicals were degraded by the changing sediment bacteria. Time-course monitoring of the degradation activities of key bacteria thus enables assessment of the fate of dye pollutants in river sediments. PMID:27232990

  12. Natural and anthropogenic factors controlling the dissolved organic carbon concentrations and fluxes in a large tropical river, India.

    PubMed

    Balakrishna, K; Kumar, Itta Arun; Srinikethan, G; Mugeraya, Gopal

    2006-11-01

    Carbon studies in tropical rivers have gained significance since it was realized that a significant chunk of anthropogenic CO(2) emitted into the atmosphere returns to the biosphere, that is eventually transported by the river and locked up in coastal sediments for a few thousand years. Carbon studies are also significant because dissolved organic carbon (DOC) is known to complex the toxic trace metals in the river and carry them in the dissolved form. For the first time, this work has made an attempt to study the variations in DOC concentrations in space and time for a period of 19 months, and estimate their fluxes in the largest peninsular Indian river, the Godavari at Rajahmundry. Anthropogenic influence on DOC concentrations possibly from the number of bathing ghats along the banks and domestic sewage discharge into the river are evident during the pre-monsoon of 2004 and 2005. The rise in DOC concentrations at the onset of monsoon could be due to the contributions from flood plains and soils from the river catchment. Spatial variations highlighted that the DOC concentrations in the river are affected more by the anthropogenic discharges in the downstream than in the upstream. The discharge weighted DOC concentrations in the Godavari river is 3-12 times lower than Ganga-Brahmaputra, Indus and major Chinese rivers. The total carbon fluxes from the Godavari into the Bay of Bengal is insignificant (0.5%) compared to the total carbon discharges by major rivers of the world into oceans. PMID:16738757

  13. Interplay between ecology and geomorphology in river systems

    NASA Astrophysics Data System (ADS)

    Muneepeerakul, R.; Rodriguez-Iturbe, I.

    2005-12-01

    It can be shown by a simple single-species model that disturbance may increase plant population if its intrinsic growth rate is sufficiently high. It does so when the population that controls propagule production is differentiated from the one that limits propagule establishment and only the latter is affected by the disturbance. In river systems, dispersal already causes similar differentiation, while disturbance is also present and heterogeneous. Consequently, the dynamics of plants in the production and transportation zones of a river system are expected to differ from the mean-field system and from each other. These issues are studied through a structured metapopulation model. The random nature of growth rate and disturbance due to hydrological fluctuation and the non-monotonic response to disturbance of plant population are likely to have important consequences on ecological and geomorphic evolution and patterns of river networks.

  14. Effect of environmental parameters on the inactivation of the waterborne pathogen Campylobacter in a Mediterranean river.

    PubMed

    Rodríguez, S; Araujo, R

    2012-03-01

    Campylobacter is a major waterborne pathogen that can be found in rivers of the Mediterranean area. Characteristics of these rivers change throughout the seasons due to variations in environmental parameters. As these variations may affect water survival of Campylobacter, we analyzed it in the Llobregat River using three approaches whose complexity increase progressively: (i) river water microcosms in the laboratory subjected to varying temperatures; (ii) in situ experiments carried out in the river, in which bacteria were exposed to varying levels of environmental parameters; and (iii) monitoring of thermotolerant Campylobacter in the river over two years. Campylobacter was quantified using the most probable number (MPN) method. The results showed that an increase in water temperature accelerates Campylobacter inactivation, measured as the loss of culturability. In situ experiments revealed that inactivation rates were also affected by sunlight, but not by pH, oxygen concentration or water conductivity. These observations are supported by the seasonality detected in Llobregat River. Campylobacter inactivation was fastest in spring and summer, when temperature and solar radiation were at their highest. The results highlight the importance of considering the inactivation rates in natural conditions to improve the monitoring of this pathogen and thus evaluate properly the health risk associated to water. PMID:22361705

  15. The rivers of civilization

    NASA Astrophysics Data System (ADS)

    Macklin, Mark G.; Lewin, John

    2015-04-01

    The hydromorphic regimes that underpinned Old World river-based civilizations are reviewed in light of recent research. Notable Holocene climatic changes varied from region to region, whilst the dynamics of floodplain environments were equally diverse, with river channel changes significantly affecting human settlement. There were longer-term trends in Holocene hydroclimate and multi-centennial length 'flood-rich' and 'flood-poor' episodes. These impacted on five identified flooding and settlement scenarios: (i) alluvial fans and aprons; (ii) laterally mobile rivers; (iii) rivers with well-developed levees and flood basins; (iv) river systems characterised by avulsions and floodouts; and (v) large river-fed wetlands. This gave a range of changes that were either more or less regular or incremental from year-to-year (and thus potentially manageable) or catastrophic. The latter might be sudden during a flood event or a few seasons (acute), or over longer periods extending over many decades or even centuries (chronic). The geomorphic and environmental impacts of these events on riparian societies were very often irreversible. Contrasts are made between allogenic and autogenic mechanism for imposing environmental stress on riverine communities and a distinction is made between channel avulsion and contraction responses. Floods, droughts and river channel changes can precondition as well as trigger environmental crises and societal collapse. The Nile system currently offers the best set of independently dated Holocene fluvial and archaeological records, and the contrasted effects of changing hydromorphological regimes on floodwater farming are examined. The persistence of civilizations depended essentially on the societies that maintained them, but they were also understandably resilient in some environments (Pharaonic Egypt in the Egyptian Nile), appear to have had more limited windows of opportunity in others (the Kerma Kingdom in the Nubian Nile), or required

  16. Comprehensive Evaluation of Plasma 7-Ketocholesterol and Cholestan-3β,5α,6β-Triol in an Italian Cohort of Patients Affected by Niemann-Pick Disease due to NPC1 and SMPD1 Mutations.

    PubMed

    Romanello, Milena; Zampieri, Stefania; Bortolotti, Nadia; Deroma, Laura; Sechi, Annalisa; Fiumara, Agata; Parini, Rossella; Borroni, Barbara; Brancati, Francesco; Bruni, Amalia; Russo, Cinzia V; Bordugo, Andrea; Bembi, Bruno; Dardis, Andrea

    2016-04-01

    Niemann-Pick C disease (NPCD) is a rare autosomal recessive neurovisceral disorder with a heterogeneous clinical presentation. Cholestan-3β,5α,6β-triol and 7-ketocholesterol have been proposed as biomarkers for the screening of NPCD. In this work, we assessed oxysterols levels in a cohort of Italian patients affected by NPCD and analyzed the obtained results in the context of the clinical, biochemical and molecular data. In addition, a group of patients affected by Niemann-Pick B disease (NPBD) were also analyzed. NPC patients presented levels of both oxysterols way above the cut off value, except for 5 siblings presenting the variant biochemical phenotype who displayed levels of 3β,5α,6β-triol below or just above the cut-off value; 2 of them presented also normal levels of 7-KC. Both oxysterols were extremely high in a patient presenting the neonatal systemic lethal phenotype. All NPB patients showed increased oxysterols levels. In conclusion, the reported LC-MS/MS assay provides a robust non-invasive screening tool for NPCD. However, false negative results can be obtained in patients expressing the variant biochemical phenotype. These data strengthen the concept that the results should always be interpreted in the context of the patients' clinical picture and filipin staining and/or genetic studies might still be undertaken in patients with normal levels of oxysterols if symptoms are highly suggestive of NPCD. Both oxysterols are significantly elevated in NPB patients; thus a differential diagnosis should always be performed in patients presenting isolated hepatosplenomegaly, a common clinical sign of both NPCD and NPBD.

  17. Dual nitrate isotopes in the Dutch and German Wadden Sea and its tributary rivers

    NASA Astrophysics Data System (ADS)

    Sanders, Tina; Wiese, Philipp; Dähnke, Kirstin

    2016-04-01

    The Dutch and German Wadden Sea is threatened by the river-induced eutrophication due to riverine nitrate. Despite reduction of nutrient inputs to rivers in the past decades, nitrate inputs remain problematic, also because the estuary of one of the main contributing rivers, the Elbe River, has now developed from a net nitrate sink to a nitrate source. During a sampling campaign in August 2014 we measured nitrate concentration and dual isotope signatures in the Wadden Sea and in two contributing rivers, the Ems and the Elbe River. Our goal was to assess individual riverine contributions and turnover mechanisms of nitrate in the estuaries and the Wadden Sea itself using dual nitrate isotopes as fingerprint signatures. Nitrate concentration in the Ems River and Estuary twice exceeded that of the Elbe River. δ15N and δ18O of nitrate nevertheless showed that denitrification was active in the Ems estuary, removing nitrate, whereas nitrification produced new nitrate in the Elbe Estuary. Surprisingly, Wadden Sea samples appeared not to be entirely dominated by these two riverine source signatures. This suggests that additional turnover mechanisms in the Wadden Sea itself or inputs of nitrate from the open North Sea additionally affect the isotope composition of nitrate in the Dutch and German Wadden Sea.

  18. Columbia River Component Data Evaluation Summary Report

    SciTech Connect

    C.S. Cearlock

    2006-08-02

    The purpose of the Columbia River Component Data Compilation and Evaluation task was to compile, review, and evaluate existing information for constituents that may have been released to the Columbia River due to Hanford Site operations. Through this effort an extensive compilation of information pertaining to Hanford Site-related contaminants released to the Columbia River has been completed for almost 965 km of the river.

  19. Mercury Loads in the South River and Simulation of Mercury Total Maximum Daily Loads (TMDLs) for the South River, South Fork Shenandoah River, and Shenandoah River: Shenandoah Valley, Virginia

    USGS Publications Warehouse

    Eggleston, Jack

    2009-01-01

    Due to elevated levels of methylmercury in fish, three streams in the Shenandoah Valley of Virginia have been placed on the State's 303d list of contaminated waters. These streams, the South River, the South Fork Shenandoah River, and parts of the Shenandoah River, are downstream from the city of Waynesboro, where mercury waste was discharged from 1929-1950 at an industrial site. To evaluate mercury contamination in fish, this total maximum daily load (TMDL) study was performed in a cooperative effort between the U.S. Geological Survey, the Virginia Department of Environmental Quality, and the U.S. Environmental Protection Agency. The investigation focused on the South River watershed, a headwater of the South Fork Shenandoah River, and extrapolated findings to the other affected downstream rivers. A numerical model of the watershed, based on Hydrological Simulation Program-FORTRAN (HSPF) software, was developed to simulate flows of water, sediment, and total mercury. Results from the investigation and numerical model indicate that contaminated flood-plain soils along the riverbank are the largest source of mercury to the river. Mercury associated with sediment accounts for 96 percent of the annual downstream mercury load (181 of 189 kilograms per year) at the mouth of the South River. Atmospherically deposited mercury contributes a smaller load (less than 1 percent) as do point sources, including current discharge from the historic industrial source area. In order to determine how reductions of mercury loading to the stream could reduce methylmercury concentrations in fish tissue below the U.S. Environmental Protection Agency criterion of 0.3 milligrams per kilogram, multiple scenarios were simulated. Bioaccumulation of mercury was expressed with a site-specific exponential relation between aqueous total mercury and methylmercury in smallmouth bass, the indicator fish species. Simulations indicate that if mercury loading were to decrease by 98.9 percent from 189

  20. 78 FR 79434 - Sabine River Authority of Texas and Sabine River Authority, State of Louisiana; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-30

    ... Energy Regulatory Commission Sabine River Authority of Texas and Sabine River Authority, State of...) for the project. The existing project is located on the Sabine River between river mile (RM) 147 and RM 279, affecting lands and waters in Panola, Shelby, Sabine, and Newton Counties, Texas, and De...

  1. Arctic River organic matter transport

    NASA Astrophysics Data System (ADS)

    Raymond, Peter; Gustafsson, Orjan; Vonk, Jorien; Spencer, Robert; McClelland, Jim

    2016-04-01

    Arctic Rivers have unique hydrology and biogeochemistry. They also have a large impact on the Arctic Ocean due to the large amount of riverine inflow and small ocean volume. With respect to organic matter, their influence is magnified by the large stores of soil carbon and distinct soil hydrology. Here we present a recap of what is known of Arctic River organic matter transport. We will present a summary of what is known of the ages and sources of Arctic River dissolved and particulate organic matter. We will also discuss the current status of what is known about changes in riverine organic matter export due to global change.

  2. Chemical weathering and associated carbon-dioxide consumption in a tropical river basin (Swarna River), Southwestern India

    NASA Astrophysics Data System (ADS)

    Muguli, T.; Gurumurthy, G. P.; Balakrishna, K.; Audry, S.; Riotte, J.; Braun, J.; Chadaga, M.; Shankar HN, U.

    2013-12-01

    Chemical weathering in river basins forms the key process to study the global climate change on a long term scale due to its association with the carbon sequestration. Water samples from a west flowing tropical river (Swarna River) of Southern India were collected for a period of two years to study the chemical weathering process and to quantify the weathering and associated carbon-dioxide consumption rates in the river basin. In addition, the major ion chemistry of Swarna River is studied for the first time on a spatial and temporal (monthly) scale to decipher the factors (lithology, precipitation/ discharge, temperature, slope and physical weathering) controlling the chemical weathering process. Swarna River originates in Western Ghats at an altitude of 1100 m above mean sea level and flows westwards draining Peninsular Gneiss and Dharwar Schist to join the Arabian Sea near Udupi. The river basin receives annual rainfall of 4500 mm and experiences warm climate with average temperature of 30°C. Major ion composition and radiogenic strontium isotopic composition measured in the Swarna river water reflects the influence of silicate rocks in the basin. The river water chemistry is found to be least affected by anthropogenic impact; however, the effect of evaporation is observed on few samples during the peak dry season. The atmospheric inputs and carbonate contributions to the river water are corrected to estimate the silicate weathering rate (SWR) and the associated carbon-dioxide consumption rate (CCR) using local rainwater and bed rock composition respectively. The SWR and CCR in the Swarna river basin are estimated to be 46 tons/km2/yr and 4.4 x 10^5 mol/km2/yr respectively. This estimation is observed to be relatively higher than the recently reported SWR and CCR in the adjacent larger Nethravati river basin (Gurumurthy et al., 2012). The increased rate could be attributed to the relatively higher precipitation in the Swarna river basin than the lithological

  3. Salinity and flow relations and effects of reduced flow in the Chassahowitzka River and Homosassa River estuaries, southwest Florida

    USGS Publications Warehouse

    Yobbi, D.K.; Knochenmus, L.A.

    1989-01-01

    The Chassahowitzka and Homosassa Rivers Florida, are spring-fed streams flowing into the Gulf of Mexico that may be affected by future development of groundwaters. Reduction of streamflow may cause an upstream movement of saltwater in the rivers. Data on flow, tide, and salinity define the physical characteristics of both estuaries. Vertical and longitudinal salinity profiles indicate that the estuaries are reasonably well mixed for the streamflow and high-tide conditions observed during the study. Estimates of the daily maximum upstream locations of the vertically averaged 3-ppt and 5-ppt salinities in the Chassahowitzka River and the vertically averaged 2-ppt and 5-ppt salinities in the Homosassa River are described by multiple linear regression analysis using daily mean streamflow of each river and high-tide stage of the gulf. For the vertically averaged 3-ppt and 2-ppt salinities, the square of the correlation coefficient for the predictive equations ranged from 0.77 to 0.85. For the vertically averaged 5-ppt salinities, the square of the correlation coefficient for the predictive equations ranged from 0.73 to 0.88. Upstream movement of salt-water due to pumping 40 million gal/day from a well field near the headwater springs of the Chassahowitzka and Homosassa Rivers was determined. Pumping at this rate from the Chassahowitzka River would cause a 15% reduction of average spring flow, resulting in an upstream movement of both the vertically averaged 3-ppt and 5-ppt of about 0.3 mile. In the Homosassa River, pumping would cause a 13% reduction of average spring flow, resulting in an upstream movement of both the vertically averaged 2-ppt and 5-ppt salinities of about 0.1 mile. (USGS)

  4. Precipitation and river water chemistry of the Piracicaba River basin, southeast Brazil.

    PubMed

    Williams, M R; Filoso, S; Martinelli, L A; Lara, L B; Camargo, P B

    2001-01-01

    Annual precipitation and river water volumes and chemistry were measured from 1995 to 1998 in a mesoscale agricultural area of southeast Brazil. Precipitation was mildly acidic and solute concentrations were higher in the west than in the east of the basin. Combustion products from biomass burning, automobile exhaust, and industry typically accumulate in the atmosphere from March until October and are responsible for seasonal differences observed in precipitation chemistry. In river waters, the volume-weighted mean (VWM) concentrations of major solutes at 10 sites across the basin were generally lower at upriver than at downriver sampling sites for most solutes. Mass balances for major solutes indicate that, as a regional entity, the Piracicaba River basin was a net sink of H+, PO4(3-), and NH4+, and a net source of other solutes. The main stem of the Piracicaba River had a general increase in solute concentrations from upriver to downriver sampling sites. In contrast, NO3- and NH4+ concentrations increased in the mid-reach sampling sites and decreased due to immobilization or utilization in the mid-reach reservoir, and there was denitrification immediately downriver of this reservoir. Compared with tributaries of the Chesapeake Bay estuary, the Piracicaba River is affected more by point-source inputs of raw sewage and industrial wastes than nonpoint agricultural runoff high in N and P. Inputs of N and C are responsible for a degradation of water quality at downriver sampling sites of the Piracicaba River drainage, and water quality could be considerably improved by augmenting sewage treatment.

  5. The effect of discharge and water quality of the Alafia River, Hillsborough River, and the Tampa Bypass Canal on nutrient loading to Hillsborough Bay, Florida

    USGS Publications Warehouse

    Stoker, Y.E.; Levesque, V.A.; Woodham, W.M.

    1996-01-01

    Techniques to measure discharge and nutrient loads in the tidally affected portions of two major rivers tributary to Tampa Bay, the Alafia River and the Hillsborough River, were developed and tested. Discharge, water quality, and total phosphorus and total nitrogen loads for the period April 1, 1991, through March 31, 1992, were evaluated and compared with discharge,water quality, and loads at long-term, nontidal gages in the basins. Long-term discharge and water-quality characteristics at selected sites in the Alafia river and Hillsborough River basins were evaluated. A long-term, decreasing trend in annual-mean discharge was observed for discharges at the Alafia River, Sulphur Springs, and Hillsborough River. Low-flow and high-flow characteristics in the Alafia River and Hillsborough River have changed as well. The decreasing trend in the Alafia River discharges is not due to deficient rainfall but probably is due to decreased ground-water inflow to the river because of long-term declines in the potentiometric surface of the Upper Floridan aquifer. Daily-mean discharges at the mouth of the Alafia River were more variable than discharges at the long-term gage upstream. Daily-mean discharge near the mouth of the river was negative at times, indicating a net loss of water from the river. Daily-mean discharge from the Hillsborough River was minimal from Apil to May 1991, and from late September 1991 to March 1992. During these periods, discharge from Sulphur Springs was a major source of freshwater to the tidally affected reach of the river. Concentrations of total phosphorus and orthophosphorus in the Alafia River above Lithia Springs were the greatest in the 1960's and have generally declined since then. Total nitrogen concentrations have been declining since about 1981. However, increases in nitrate plus nitrite nitrogen concentrations are occurring in Lithia Springs, a second-magnitude spring that flows into the Alafia River. Specific conductance of water

  6. River water quality modelling under drought situations - the Turia River case

    NASA Astrophysics Data System (ADS)

    Paredes-Arquiola, Javier; Macián, Javier; Pedro-Monzonís, María; Belda, Edgar; Momblanch, Andrea; Andreu, Joaquín

    2016-10-01

    Drought and water shortage effects are normally exacerbated due to collateral impacts on water quality, since low streamflow affects water quality in rivers and water uses depend on it. One of the most common problems during drought conditions is maintaining a good water quality while securing the water supply to demands. This research analyses the case of the Turia River Water Resource System located in Eastern Spain. Its main water demand comes as urban demand from Valencia City, which intake is located in the final stretch of the river, where streamflow may become very low during droughts. As a result, during drought conditions concentrations of pathogens and other contaminants increase, compromising the water supply to Valencia City. In order to define possible solutions for the above-mentioned problem, we have developed an integrated model for simulating water management and water quality in the Turia River Basin to propose solutions for water quality problems under water scarcity. For this purpose, the Decision Support System Shell AQUATOOL has been used. The results demonstrate the importance of applying environmental flows as a measure of reducing pollutant's concentration depending on the evolution of a drought event and the state of the water resources system.

  7. Water quality of the Tlikakila River and five major tributaries to Lake Clark, Lake Clark National Park and Preserve, Alaska, 1999-2001

    USGS Publications Warehouse

    Brabets, Timothy P.

    2002-01-01

    The Tlikakila River Basin, located in Lake Clark National Park and Preserve, drains an area of 622 square miles. This watershed comprises about 21 percent of the Lake Clark Basin, making it one of the major tributaries to Lake Clark. Due to a sharp decline in sockeye salmon population and the lack of hydrologic data, the Tlikakila River and five other major tributaries to Lake Clark were studied during the summer runoff months (May through September) from 1999 through 2001 as part of a cooperative study with the National Park Service. Measurements of pH and dissolved oxygen concentrations of the Tlikakila River are within acceptable limits for fish survival. Water temperatures at the measurement site reach 0 ?C during the winter and this part of the Tlikakila River may not be suitable for fish. Water temperatures are within acceptable limits for fish during the summer months. The Tlikakila River is a calcium bicarbonate type water with a low buffering capacity. Concentrations of un-ionized ammonia are well below the recommended value of 0.02 mg/L for fish propagation. Annual transport of suspended sediment by the Tlikakila River into Lake Clark ranged from 0.4 to 1.5 million tons during 1999?2001. The fine sediment from the Tlikakila River disperses through the lake over the summer, affecting light transmissivity. Most runoff from the Tlikakila River occurs from mid-to-late May through September. Average discharge for these months during 1999?2001 was 6,600 ft?/s. Total annual inflow to Lake Clark from the Tlikakila River ranged from 32 to 45 percent of the total inflow. The relatively high proportion of inflow is due to the presence of glaciers, which comprise 36 percent of the watershed. Monthly measurements of flow, field water-quality parameters, alkalinity, and suspended sediment were collected on the remaining five tributaries to Lake Clark: the Chokotonk River, Currant Creek, the Kijik River, the Tanalian River and the Chulitna River. Similar to the

  8. Herbicide and nutrient transport from an irrigation district into the South Saskatchewan River.

    PubMed

    Cessna, A J; Elliott, J A; Tollefson, L; Nicholaichuk, W

    2001-01-01

    Pesticides and nutrients can be transported from treated agricultural land in irrigation runoff and thus can affect the quality of receiving waters. A 3-yr study was carried out to assess possible detrimental effects on the downstream water quality of the South Saskatchewan River due to herbicide and plant nutrient inputs via drainage water from an irrigation district. Automated water samplers and flow monitors were used to intensively sample the drainage water and to monitor daily flows in two major drainage ditches, which drained approximately 40% of the flood-irrigated land within the irrigation district. Over three years, there were no detectable inputs of ethalfluralin into the river and those of trifluralin were less than 0.002% of the amount applied to flood-irrigated fields. Inputs of MCPA, bromoxynil, dicamba and mecoprop were 0.06% or less of the amounts applied, whereas that for clopyralid was 0.31%. The relatively higher input (1.4%) of 2,4-D to the river was probably due its presence in the irrigation water. Corresponding inputs of P (as total P) and N (as nitrate plus ammonia) were 2.2 and 1.9% of applied fertilizer, respectively. Due to dilution of the drainage water in the river, maximum daily herbicide (with the exception of 2,4-D) and nutrient loadings to the river would not have resulted in significant concentration increases in the river water. There was no consistent remedial effect on herbicides entering the river due to passage of the drainage water through a natural wetland. In contrast, a considerable portion of the nutrients entering the river originated from the wetland.

  9. Cross-shelf transport and dispersion due to baroclinic instabilities

    NASA Astrophysics Data System (ADS)

    Thyng, Kristen; Hetland, Robert

    2014-05-01

    The dominant forcing mechanisms for the circulation in the northwestern Gulf of Mexico are largely determined by location relative to the shelf break. On the inner shelf, the flow is mostly controlled by the wind and on the outer shelf is affected by the mesoscale loop-current eddies. However, in the summer, baroclinic instabilities can develop along the boundary of the mid-shelf river plume front, leading to large eddies (~50 km length scale) that can reach across the entire shelf and strongly affect the local flow field. These instabilities advect fresher water toward the shelf edge and pull denser water back toward the coast. The details of how the flow crosses between these two regimes is of interest because it controls the flux of river-borne biogeochemical properties to the deep ocean, as well as for the potential onshore transport of oil from offshore spills. We approach this problem using a high resolution numerical model of the Texas-Louisiana shelf run using the Regional Ocean Modeling System (ROMS) and a Lagrangian particle tracking model (TRACMASS). By initializing drifters at the sources of fresh water (the Atchafalaya and Mississippi rivers) in the numerical model, we are able to explicitly track its trajectory through the numerical domain in time. These trajectories can then be used to characterize the cross-shelf transport and lateral dispersion due to the instabilities caused by the presence of the fresher water. We expect the transport and dispersion to be enhanced when compared with these quantities at other times of the year when the instabilities are not present, as well as with other regions of the shelf break that are farther from the plume edge area. Additionally, an idealized numerical model of a shelf break with both horizontal and vertical density gradients has been run through relevant parameter spaces to examine the range of baroclinic instabilities. Drifters are run in these simulations for comparison of transport and dispersion with

  10. River restoration

    NASA Astrophysics Data System (ADS)

    Wohl, Ellen; Angermeier, Paul L.; Bledsoe, Brian; Kondolf, G. Mathias; Macdonnell, Larry; Merritt, David M.; Palmer, Margaret A.; Poff, N. Leroy; Tarboton, David

    2005-10-01

    River restoration is at the forefront of applied hydrologic science. However, many river restoration projects are conducted with minimal scientific context. We propose two themes around which a research agenda to advance the scientific basis for river restoration can be built. First, because natural variability is an inherent feature of all river systems, we hypothesize that restoration of process is more likely to succeed than restoration aimed at a fixed end point. Second, because physical, chemical, and biological processes are interconnected in complex ways across watersheds and across timescales, we hypothesize that restoration projects are more likely to be successful in achieving goals if undertaken in the context of entire watersheds. To achieve restoration objectives, the science of river restoration must include (1) an explicit recognition of the known complexities and uncertainties, (2) continued development of a theoretical framework that enables us to identify generalities among river systems and to ask relevant questions, (3) enhancing the science and use of restoration monitoring by measuring the most effective set of variables at the correct scales of measurement, (4) linking science and implementation, and (5) developing methods of restoration that are effective within existing constraints. Key limitations to river restoration include a lack of scientific knowledge of watershed-scale process dynamics, institutional structures that are poorly suited to large-scale adaptive management, and a lack of political support to reestablish delivery of the ecosystem amenities lost through river degradation. This paper outlines an approach for addressing these shortcomings.

  11. Mississippi River

    Atmospheric Science Data Center

    2014-05-15

    article title:  Mississippi River Flooding during Spring 2001     ... the mighty river has flooded many times. The largest flood recorded in the lower valley occurred in 1927 and the largest in the upper Mississippi in 1993. In April 2001 another flooding event in the upper Mississippi was recorded by the Multi-angle Imaging ...

  12. Amazon River

    Atmospheric Science Data Center

    2013-04-17

    ... River originates in the Peruvian Andes as tiny mountain streams that eventually combine to form one of the world's mightiest rivers. ... Earth's discharge into the oceans. Millions of cubic feet of water empty into the Atlantic every second, and the effluent is transported ...

  13. Groundwater Discharge and Salinity Sources to an Impaired Major River in a Semi-Arid Coastal Region: Nueces River, Texas

    NASA Astrophysics Data System (ADS)

    Murgulet, V.; Murgulet, D.; Hay, R.

    2015-12-01

    Nueces River, an impaired stream located on the South Texas Gulf coast area, has shown water quality degradation due to to increased salinity levels in areas adjacent to the Calallen saltwater reservoir dam. This study investigates the role of submarine groundwater discharge in delivering increased salt contents to the river and how the subsurface hydrology is affected by the presence of a salt barrier (i.e. saltwater dam) which separates the tidal and non-tidal parts of the Nueces river basin. Thus, a combination of resistivity profiling and elemental and stable isotope geochemistry methods has been applied to portions of the river located downstream (tidal) and upstream (non-tidal) of the dam. Preliminary data show that salinity levels gradually increases at the river bank indicating that groundwater is likely a source of solutes to the river in the upper, non-tidal portion. The presence of vertical upwelling of conductive groundwater plumes is also revealed by marine resistivity profiles collected along the river. Different sampling during the spring and summer of 2014 show higher concentration values of major ions (i.e., calcium, magnesium, sodium, potassium, chloride, etc.) and salinity of pore water for the upstream river at several locations while it remains relatively constant for bottom- and surface water. In addition, because the groundwater and porewater have slightly lower pH values, a shift to more acidic surface water accompanied by some increases in dissolved major ion concentrations and salinity suggest that groundwater might represent a source of increased salt content in the upper portion of the river. On the other hand, downstream dissolved major ion concentrations generally decrease in pore- and bottom water from spring to summer and are correlated with decreases in salinity while surface water becomes more saline with an increase in major ions. Therefore, these preliminary data indicate different hydrology systems of the two portions of the

  14. The economic value of Trinity River water

    USGS Publications Warehouse

    Douglas, A.J.; Taylor, J.G.

    1999-01-01

    The Trinity River, largest tributary of the Klamath River, has its head-waters in the Trinity Alps of north-central California. After the construction of Trinity Dam in 1963, 90% of the Trinity River flow at Lewiston was moved to the Sacramento River via the Clear Creek Tunnel, a manmade conduit. Hydropower is produced at four installations along the route of Trinity River water that is diverted to the Sacramento River, and power production at three of these installations would diminish if no Trinity River water were diverted to the Sacramento River. After Trinity River water reaches the Sacramento River, it flows toward the Sacramento-San Joaquin Delta and San Francisco Bay. Trinity River water is pumped via Bureau of Reclamation canals and pumps to the northern San Joaquin Valley, where it is used for irrigated agriculture. The social cost of putting more water down the Trinity River is the sum of the value of the foregone consumer surplus from hydropower production as well as the value of the foregone irrigation water. Sharply diminished instream flows have also severely affected the size and robustness of Trinity River salmon, steelhead, shad and sturgeon runs. Survey data were used to estimate the non-market benefits of augmenting Trinity River instream flows by letting more water flow down the Trinity and moving less water to the Sacramento River. Preservation benefits for Trinity River instream flows and fish runs are $803 million per annum for the scenario that returns the most water down the Trinity River, a value that greatly exceeds the social cost estimate.The Trinity River, largest tributary of the Klamath River, has its headwaters in the Trinity Alps of north-central California. After the construction of Trinity Dam in 1963, 90% of the Trinity River flow at Lewiston was moved to the Sacramento River via the Clear Creek Tunnel, a manmade conduit. Hydropower is produced at four installations along the route of Trinity River water that is diverted to the

  15. Sediment-quality assessment of the Lower Oconee River

    USGS Publications Warehouse

    Lasier, P.J.; Winger, P.V.; Shelton, J.L.; Bogenrieder, K.J.

    2004-01-01

    Sediment quality was assessed at multiple sites in the lower Oconee River, GA to identify contaminants potentially affecting the survival of an endemic ?At-Risk? species of fish, the robust redhorse (Moxostoma robustum). Five major tributaries that drain urban and agricultural watersheds enter this stretch of river and several carry permitted municipal and industrial effluents containing Cd, Cu, and Zn. Sediments for chemical analyses and toxicity tests with Hyalella azteca (Amphipoda) were collected at 12 locations that included sites above and below the major tributaries. Compared to national data bases and to the nearby Apalachicola-Chattahoochee-Flint watershed, sediments from the Oconee River had elevated concentrations of Cr, Cu, Hg and Zn. Zinc concentrations showed a marked increase in sediment downstream of the confluence of Buffalo Creek demonstrating contributions from permitted municipal and industrial effluents discharged to that tributary. When exposed to these sediments, growth of H. azteca was significantly reduced. Amphipod growth was also reduced when exposed to sediments collected from another site due to toxicity from Cr. Sediments in the lower Oconee River appear to be impaired due to metal contamination and could pose a threat to organisms, such as the robust redhorse, that are closely associated with this matrix during their life cycle.

  16. Linking channel hydrology with riparian wetland accretion in tidal rivers

    USGS Publications Warehouse

    Ensign, Scott H.; Noe, Gregory B.; Hupp, Cliff R.

    2014-01-01

    The hydrologic processes by which tide affects river channel and riparian morphology within the tidal freshwater zone are poorly understood, yet are fundamental to predicting the fate of coastal rivers and wetlands as sea level rises. We investigated patterns of sediment accretion in riparian wetlands along the non-tidal through oligohaline portion of two coastal plain rivers in Maryland, U.S.A., and how flow velocity, water level, and suspended sediment concentration (SSC) in the channel may have contributed to those patterns. Sediment accretion was measured over a one year period using artificial marker horizons, channel hydrology was measured over a one month period using acoustic Doppler current profilers, and SSC was predicted from acoustic backscatter. Riparian sediment accretion was lowest at the non-tidal sites (mean and standard deviation = 8 ± 8 mm yr-1), highest at the upstream tidal freshwater forested wetlands (TFFW) (33 ± 28 mm yr-1), low at the midstream TFFW (12 ± 9 mm yr-1), and high at the oligohaline (fresh-to-brackish) marshes (19 ± 8 mm yr-1). Channel maximum flood and ebb velocity was 2-fold faster at the oligohaline than tidal freshwater zone on both tidal rivers, corresponding with the differences in in-channel SSC: the oligohaline zone's SSC was more than double the tidal freshwater zone's, and was greater than historical SSC at the non-tidal gages. The tidal wave characteristics differed between rivers, leading to significantly greater in-channel SSC during floodplain inundation in the weakly convergent than the strongly convergent tidal river. Overall sediment accretion was higher in the embayed river likely due to a single storm discharge and associated sedimentation.

  17. Linking channel hydrology with riparian wetland accretion in tidal rivers

    NASA Astrophysics Data System (ADS)

    Ensign, Scott H.; Noe, Gregory B.; Hupp, Cliff R.

    2014-01-01

    hydrologic processes by which tide affects river channel and riparian morphology within the tidal freshwater zone are poorly understood yet are fundamental to predicting the fate of coastal rivers and wetlands as sea level rises. We investigated patterns of sediment accretion in riparian wetlands along the nontidal through oligohaline portion of two coastal plain rivers in Maryland, U.S., and how flow velocity, water level, and suspended sediment concentration (SSC) in the channel may have contributed to those patterns. Sediment accretion was measured over a 1 year period using artificial marker horizons, channel hydrology was measured over a 1 month period using acoustic Doppler current profilers, and SSC was predicted from acoustic backscatter. Riparian sediment accretion was lowest at the nontidal sites (mean and standard deviation = 8 ± 8 mm yr-1), highest at the upstream tidal freshwater forested wetlands (TFFW) (33 ± 28 mm yr-1), low at the midstream TFFW (12 ± 9 mm yr-1), and high at the oligohaline (fresh-to-brackish) marshes (19 ± 8 mm yr-1). Channel maximum flood and ebb velocity was twofold faster at the oligohaline than tidal freshwater zone on both tidal rivers, corresponding with the differences in in-channel SSC: The oligohaline zone's SSC was more than double the tidal freshwater zone's and was greater than historical SSC at the nontidal gages. The tidal wave characteristics differed between rivers, leading to significantly greater in-channel SSC during floodplain inundation in the weakly convergent than the strongly convergent tidal river. High sediment accretion at the upstream TFFW was likely due to high river discharge following a hurricane.

  18. [An ecological compensation standard based on water environmental capacity of Kouhe River, Liaoning Province, China].

    PubMed

    Hou, Chun-fang; Cheng, Quan-guo; Li, Ye

    2015-08-01

    Kouhe River water pollution caused by industry, agriculture and life sewage, not only reduced the water use function, but also directly affected the quality of Qinghe River. Due to the lack of effective management of water resources, the irrational use and water environment pollution occurred in Kouhe River basin. In this paper, in order to maintain the sustainable development of Kouhe River basin, taking Xifeng County and Kaiyuan City as two control units, COD as pollution factor, the water environmental capacity of Kouhe River basin was calculated. Combined with water quality monitoring data, river environment functional zone, pollution census data and the recovery cost of COD, an ecological compensation standard was determined. When the guarantee rates were 50%, 75%, and the average flow of the driest month in recent 10 years, the corresponding compensation standards of Xifeng County to downstream Kaiyuan City were 390.9 x 10(4), 448.6 x 10(4) and 514 x 10(4) yuan · a(-1), respectively. The river basin ecological compensation mechanism was put forward which should include ecological compensation fund raising, allocation and supervision. PMID:26685611

  19. Application of Water Quality Model of Jordan River to Evaluate Climate Change Effects on Eutrophication

    NASA Astrophysics Data System (ADS)

    Van Grouw, B.

    2015-12-01

    The Jordan River is a 51 mile long freshwater stream in Utah that provides drinking water to more than 50% of Utah's population. The various point and nonpoint sources introduce an excess of nutrients into the river. This excess induces eutrophication that results in an inhabitable environment for aquatic life and is expected to be exacerbated due to climate change. Adaptive measures must be evaluated based on predictions of climate variation impacts on eutrophication and ecosystem processes in the Jordan River. A Water Quality Analysis Simulation Program (WASP) model was created to analyze the data results acquired from a Total Maximum Daily Load (TMDL) study conducted on the Jordan River. Eutrophication is modeled based on levels of phosphates and nitrates from point and nonpoint sources, temperature, and solar radiation. It will simulate the growth of phytoplankton and periphyton in the river. This model will be applied to assess how water quality in the Jordan River is affected by variations in timing and intensity of spring snowmelt and runoff during drought in the valley and the resulting effects on eutrophication in the river.

  20. River Times.

    ERIC Educational Resources Information Center

    Auldridge, Teresa; And Others

    The James River is one of the most precious resources of Virginia. It was the site of the first permanent English settlement in the New World; the power of the water at the Fall Zone was a major factor in the development of Richmond; and the river served as a primary transportation route to the West via the Kanawha Canal. Both the water itself and…

  1. Changes in chemical quality of the Arkansas River in Oklahoma and Arkansas (1946-52)

    USGS Publications Warehouse

    Dover, T.B.; Geurin, J.W.

    1953-01-01

    Systematic chemical quality-of-water investigations have been carried on in both Oklahoma and Arkansas by the Geological Survey in cooperation with State and Federal agencies during the past several years. Results of the Survey's quality-of-water investigations are usually published in the annual Water-Supply Papers. However, as the Geological Survey has made no sediment investigations in the Arkansas River Basin in Oklahoma and Arkansas, the published data do not include information on sediment concentrations or loads. This report attempts to summarize information collected to date in the Arkansas River Basin of the two States, and to show as clearly as possible from present information how the chemical quality of water in the Arkansas River changes downstream from the Oklahoma-Kansas State line to its confluence with the Mississippi River, and how it is affected by tributary inflows. Additional information is being collected and further studies are planned. Hence, the conclusions reached herein may be modified by more adequate information at a later date. The Arkansas River enters Oklahoma near Newkirk on the northern boundary just east of the 97th meridian, crosses the State in a general southeasterly direction flowing past Tulsa, enters Arkansas at its western boundary north of the 35th parallel near Fort Smith, still flowing in a general southeasterly direction past Little Rock near the center of the State, and empties into the Mississippi River east of Dumas. The Arkansas River is subject to many types of pollution downstream from the Oklahoma-Kansas State line, and its inferior quality along with an erratic flow pattern has caused it to be largely abandoned as a source of municipal and industrial water supply. At the present time, the Arkansas River is not directly used as a source of public supply in any part of the basin in either Oklahoma or Arkansas. In general, the river water increases in chemical concentration downstream from the Oklahoma-Kansas State

  2. Oblique perspective of portal, due north. Bridge has gable roof ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Oblique perspective of portal, due north. Bridge has gable roof clad with wood shingles and has board and batten siding. - Watson Mill Bridge, Spanning South Fork Broad River, Watson Mill Road, Watson Mill Bridge State Park, Comer, Madison County, GA

  3. Methane Emission from Tropical Rivers

    NASA Astrophysics Data System (ADS)

    Sawakuchi, H. O.; Rasera, M. F. F. L.; Krusche, A. V.; Ballester, M. V. R.

    2012-04-01

    Inland water is already known as an important source of methane to atmosphere. Methane is produced in anaerobic environments usually find in lakes and floodplain bottom sediment. It is the main reason that almost all information regarding methane flux come from this environments. However, while floodplain dries during low water season reducing methanogenesis, rivers keep the capacity to emit methane throughout the year. Here we present preliminary results of CH4 flux measurements done in 6 large tropical rivers within the Amazon basin. We measured 17 areas using floating chamber during dry (low water) season, between September and November of 2011, in Amazon river mainstem, Araguaia, Xingu, Tapajós, Madeira, and Negro Rivers. Measured fluxes of all rivers ranged from 59.3 to 2974.4 mmol m-2 yr-1. Geomorphologic structure of channels is one important factor that contributes to this high heterogeneity due to development of low flow velocity depositional settings allowing formation of anoxic zones in rivers. Hydraulic and sediment barriers in the confluence of river channels promote the generation of natural dams which function as a trap for the suspension load favoring the deposition of organic rich muds. This kind of environment is very different from common river channels and has a stronger potential of methane emission. Average values of our flux measurements for this two river environments show that depositional areas can have much higher fluxes than the main channel, 1089.6 and 163.1 mmol m-2 yr-1, respectively. Hence, CH4 flux from these depositional zones is similar to some tropical floodplain lakes and reservoirs. Although the low flux from channel, the area covered by water is very large resulting in a significant contribution to the regional methane emission to the atmosphere. Moreover, mapping the area of these depositional river zones will give us a better idea of the magnitude of methane flux from tropical rivers.

  4. Osmium in the rivers

    SciTech Connect

    Sharma, M. |; Wasserburg, G.J.

    1997-12-01

    There is a large uncertainty in our understanding of the behavior of osmium during weathering and transport into deep oceans and the osmium budget of the oceans. The problem stems chiefly from the lack of osmium data on the dissolved load in the rivers and in the estuaries. In this study, the concentration and isotopic composition of osmium have been determined in three North American rivers (the Mississippi, the Columbia, and the Connecticut) and one river draining central Europe and flowing into the Baltic Sea (the Vistula). Osmium concentration in the Mississippi and the Vistula is about 45 femto mol kg{sup -1}; it is about 14 and 15 femto mol kg{sup -1} for the Connecticut and the Columbia, respectively. The {sup 187}Os/{sup 186}Os ratios estimated for the Mississippi and the Vistula are 10.4 and 10.7, respectively. For the Connecticut and the Columbia {sup 187}Os/{sup 186}Os = 8.8 and 14.4, respectively. Of all the rivers examined, the Mississippi is by far the largest, supplying {approximately}1.6% of the total annual world river flow. Its osmium isotopic composition is identical to the upper Mississippi valley loesses indicating (1) congruent dissolution of the bedrock and (2) little or no impact of anthropogenic sources on the osmium isotopic composition of the dissolved load. The latter observation indicates that the upper limit of the anthropogenic input in the dissolved osmium load of the Mississippi outflow is about 250 g yr{sup -1}. While the osmium concentration of the Vistula is high the isotopic composition does not appear to have been affected by substantial pollution. The river data can be used to put limits on the mean residence time of osmium in the oceans ({bar {tau}}{sub Os}) and on the osmium budget of the oceans. 17 refs., 1 fig., 1 tab.

  5. Extreme river response to climate-induced aggradation in a forested, montane basin, Carbon River, Mount Rainier National Park, Washington, United States

    NASA Astrophysics Data System (ADS)

    Beyeler, J. D.; Rossi, R. K.; Kennard, P. M.; Beason, S. R.

    2013-12-01

    Climate change is drastically affecting the alpine landscape of Mount Rainier, encouraging glacial retreat, changes in snowpack thickness and longevity, and sediment delivery to downstream fluvial systems, leading to an extremely transport limited system and aggradation of the river valleys. River aggradation encourages devastating interactions between the pro-glacial braided fluvial systems and streamside floodplain ecosystems, in most places occupied by old-growth conifer forests. Current aggradation rates of the channels, bordered by late seral stage riparian forests, inhibit floodplain development, leading to an inverted relationship between perched river channels and lower-elevation adjacent floodplains. This disequilibrium creates a steeper gradient laterally towards the floodplains, rather than downstream; promoting flooding of streamside forest, removal and burial of vegetation with coarse alluvium, incision of avulsion channels, tree mortality, wood recruitment to channels, and ultimately widening the alluviated valley towards the glacially carved hillslopes. Aggradation and loss of streamside old-growth forest poses a significant problem to park infrastructure (e.g. roads, trails, and campgrounds) due to flood damage with as frequent as a two-year event. Other park rivers, the White River and Tahoma Creek, characterize two end-member cases. Despite an extremely perched channel, the White River is relatively stable; experiencing small avulsions while the old-growth streamside forest has remained mostly intact. These relatively small avulsions however severely impact park infrastructure, causing extensive flood damage and closure of the heavily trafficked state highway. Conversely debris flows on Tahoma Creek destroyed the streamside forest and migration across the valley is uninhibited. Mature streamside forests tend to oppose avulsions, sieving wood at the channel margins, promoting sediment deposition and deflection of erosive flows. Our study seeks to

  6. The Brahmaputra tale of tectonics and erosion: Early Miocene river capture in the Eastern Himalaya

    NASA Astrophysics Data System (ADS)

    Bracciali, Laura; Najman, Yani; Parrish, Randall R.; Akhter, Syed H.; Millar, Ian

    2015-04-01

    The Himalayan orogen provides a type example on which a number of models of the causes and consequences of crustal deformation are based and it has been suggested that it is the site of a variety of feedbacks between tectonics and erosion. Within the broader orogen, fluvial drainages partly reflect surface uplift, different climatic zones and a response to crustal deformation. In the eastern Himalaya, the unusual drainage configuration of the Yarlung Tsangpo-Brahmaputra River has been interpreted either as antecedent drainage distorted by the India-Asia collision (and as such applied as a passive strain marker of lateral extrusion), latest Neogene tectonically-induced river capture, or glacial damming-induced river diversion events. Here we apply a multi-technique approach to the Neogene paleo-Brahmaputra deposits of the Surma Basin (Bengal Basin, Bangladesh) to test the long-debated occurrence and timing of river capture of the Yarlung Tsangpo by the Brahmaputra River. We provide U-Pb detrital zircon and rutile, isotopic (Sr-Nd and Hf) and petrographic evidence consistent with river capture of the Yarlung Tsangpo by the Brahmaputra River in the Early Miocene. We document influx of Cretaceous-Paleogene zircons in Early Miocene sediments of the paleo-Brahmaputra River that we interpret as first influx of material from the Asian plate (Transhimalayan arc) indicative of Yarlung Tsangpo contribution. Prior to capture, the predominantly Precambrian-Paleozoic zircons indicate that only the Indian plate was drained. Contemporaneous with Transhimalayan influx reflecting the river capture, we record arrival of detrital material affected by Cenozoic metamorphism, as indicated by rutiles and zircons with Cenozoic U-Pb ages and an increase in metamorphic grade of detritus as recorded by petrography. We interpret this as due to a progressively increasing contribution from the erosion of the metamorphosed core of the orogen. Whole rock Sr-Nd isotopic data from the same samples

  7. Water quality analysis of River Yamuna using water quality index in the national capital territory, India (2000-2009)

    NASA Astrophysics Data System (ADS)

    Sharma, Deepshikha; Kansal, Arun

    2011-12-01

    River Yamuna, in the national capital territory (NCT), commonly called Delhi (India), has been subjected to immense degradation and pollution due to the huge amount of domestic wastewater entering the river. Despite the persistent efforts in the form of the Yamuna Action Plan phase I and II (YAP) (since 1993 to date), the river quality in NCT has not improved. The restoration of river water quality has been a major challenge to the environmental managers. In the present paper, water quality index (WQI) was estimated for the River Yamuna within the NCT to study the aftereffects of the projects implemented during YAP I and II. The study was directed toward the use of WQI to describe the level of pollution in the river for a period of 10 years (2000-2009). The study also identifies the critical pollutants affecting the river water quality during its course through the city. The indices have been computed for pre-monsoon, monsoon and post-monsoon season at four locations, namely Palla, ODRB, Nizamuddin and Okhla in the river. It was found that the water quality ranged from good to marginal category at Palla and fell under poor category at all other locations. BOD, DO, total and fecal coliforms and free ammonia were found to be critical parameters for the stretch.

  8. River bed Elevation Changes and Increasing Flood Hazards in the Nisqually River at Mount Rainier National Park, Washington

    NASA Astrophysics Data System (ADS)

    Halmon, S.; Kennard, P.; Beason, S.; Beaulieu, E.; Mitchell, L.

    2006-12-01

    Mount Rainier, located in Southwestern Washington, is the most heavily glaciated volcano of the Cascade Mountain Range. Due to the large quantities of glaciers, Mount Rainier also has a large number of braided rivers, which are formed by a heavy sediment load being released from the glaciers. As sediment builds in the river, its bed increases, or aggrades,its floodplain changes. Some contributions to a river's increased sediment load are debris flows, erosion, and runoff, which tend to carry trees, boulders, and sediment downstream. Over a period of time, the increased sediment load will result in the river's rise in elevation. The purpose of this study is to monitor aggradation rates, which is an increase in height of the river bed, in one of Mount Rainier's major rivers, the Nisqually. The studied location is near employee offices and visitor attractions in Longmire. The results of this study will also provide support to decision makers regarding geological hazard reduction in the area. The Nisqually glacier is located on the southern side of the volcano, which receives a lot of sunlight, thus releasing large amounts of snowmelt and sediment in the summer. Historical data indicate that several current features which may contribute to future flooding, such as the unnatural uphill slope to the river, which is due to a major depositional event in the late 1700s where 15 ft of material was deposited in this area. Other current features are the glaciers surrounding the Nisqually glacier, such as the Van Trump and Kaultz glaciers that produced large outbursts, affecting the Nisqually River and the Longmire area in 2001, 2003, and 2005. In an effort to further explore these areas, the research team used a surveying device, total station, in the Nisqually River to measure elevation change and angles of various positions within ten cross sections along the Longmire area. This data was then put into GIS for analyzation of its current sediment level and for comparison to

  9. Environmental Impact Assessment of Sand Mining from the Small Catchment Rivers in the Southwestern Coast of India: A Case Study

    NASA Astrophysics Data System (ADS)

    Sreebha, Sreedharan; Padmalal, Damodaran

    2011-01-01

    In the past few decades, the demand for construction grade sand is increasing in many parts of the world due to rapid economic development and subsequent growth of building activities. This, in many of the occasions, has resulted in indiscriminate mining of sand from instream and floodplain areas leading to severe damages to the river basin environment. The case is rather alarming in the small catchment rivers like those draining the southwestern coast of India due to limited sand resources in their alluvial reaches. Moreover, lack of adequate information on the environmental impact of river sand mining is a major lacuna challenging regulatory efforts in many developing countries. Therefore, a scientific assessment is a pre-requisite in formulating management strategies in the sand mining-hit areas. In this context, a study has been made as a case to address the environmental impact of sand mining from the instream and floodplain areas of three important rivers in the southwestern coast of India namely the Chalakudy, Periyar and Muvattupuzha rivers, whose lowlands host one of the fast developing urban-cum-industrial centre, the Kochi city. The study reveals that an amount of 11.527 million ty-1 of sand (8.764 million ty-1 of instream sand and 2.763 million ty-1 of floodplain sand) is being mined from the midland and lowland reaches of these rivers for construction of buildings and other infrastructural facilities in Kochi city and its satellite townships. Environmental Impact Assessment (EIA) carried out as a part of this investigation shows that the activities associated with mining and processing of sands have not only affected the health of the river ecosystems but also degraded its overbank areas to a large extent. Considering the degree of degradation caused by sand mining from these rivers, no mining scenario may be opted in the deeper zones of the river channels. Also, a set of suggestions are made for the overall improvement of the rivers and its

  10. Nutrient chemistry of River Pinios (Thessalia, Greece).

    PubMed

    Bellos, D; Sawidis, T; Tsekos, I

    2004-03-01

    The impact of human activities with 3-year monitoring on the fluctuation of nutrients along the Pinios River and its tributaries were studied. Their seasonal variations throughout the years 1996-1998 were also presented. High temperatures, from June to August, cause a restriction of the water flow, an enhancement of nutrient concentration with the subsequent increase of eutrophication. High concentrations of nutrients were observed first in winter (wet period), caused by leaching of fertilizers from terrestrial systems after heavy rainfall, later during the warm months due to low water flow of the river, and at last in autumn when plant organisms began to decompose. The intensive algal and macrophyte growth (spring, summer) resulted in severe depletion of nutrients. Organic carbon showed no seasonal trend but its values were high near the estuaries. Nitrate fluxes were high at the initial station (sources) and the Titarisios tributary, whereas nitrites and ammonium were low. In contrary, the Kalentzis tributary with relatively low nitrate values showed increased values of nitrite ammonium or total nitrogen. On the other hand, the Enipeas tributary showed high SO4 values. Phosphates are remarkably present mainly after the city of Larissa, where sewage and industrial discharges occur. None of the nutrients measured in the Pinios River and its tributaries showed a clear seasonal cycle of concentration. Concentrations of nutrients and organic carbon increased as a consequence of anthropogenic inputs, particularly point discharges from sewage treatment plants (i.e. showing distinct, but variable, concentration peaks), as well as diffuse urban and/or agricultural runoff over long areas during storm events. The agricultural management, the urban pollution, mainly from Larissa City, and the climate conditions in the catchment basin (Thessalia Plain) of Pinios River and its tributaries greatly affect the chemical composition of their waters. PMID:14664870

  11. Nutrient chemistry of River Pinios (Thessalia, Greece).

    PubMed

    Bellos, D; Sawidis, T; Tsekos, I

    2004-03-01

    The impact of human activities with 3-year monitoring on the fluctuation of nutrients along the Pinios River and its tributaries were studied. Their seasonal variations throughout the years 1996-1998 were also presented. High temperatures, from June to August, cause a restriction of the water flow, an enhancement of nutrient concentration with the subsequent increase of eutrophication. High concentrations of nutrients were observed first in winter (wet period), caused by leaching of fertilizers from terrestrial systems after heavy rainfall, later during the warm months due to low water flow of the river, and at last in autumn when plant organisms began to decompose. The intensive algal and macrophyte growth (spring, summer) resulted in severe depletion of nutrients. Organic carbon showed no seasonal trend but its values were high near the estuaries. Nitrate fluxes were high at the initial station (sources) and the Titarisios tributary, whereas nitrites and ammonium were low. In contrary, the Kalentzis tributary with relatively low nitrate values showed increased values of nitrite ammonium or total nitrogen. On the other hand, the Enipeas tributary showed high SO4 values. Phosphates are remarkably present mainly after the city of Larissa, where sewage and industrial discharges occur. None of the nutrients measured in the Pinios River and its tributaries showed a clear seasonal cycle of concentration. Concentrations of nutrients and organic carbon increased as a consequence of anthropogenic inputs, particularly point discharges from sewage treatment plants (i.e. showing distinct, but variable, concentration peaks), as well as diffuse urban and/or agricultural runoff over long areas during storm events. The agricultural management, the urban pollution, mainly from Larissa City, and the climate conditions in the catchment basin (Thessalia Plain) of Pinios River and its tributaries greatly affect the chemical composition of their waters.

  12. South Asia river flow projections and their implications for water resources

    NASA Astrophysics Data System (ADS)

    Mathison, C.; Wiltshire, A. J.; Falloon, P.; Challinor, A. J.

    2015-06-01

    South Asia is a region with a large and rising population and a high dependance on industries sensitive to water resource such as agriculture. The climate is hugely variable with the region relying on both the Asian Summer Monsoon (ASM) and glaciers for its supply of fresh water. In recent years, changes in the ASM, fears over the rapid retreat of glaciers and the increasing demand for water resources for domestic and industrial use, have caused concern over the reliability of water resources both in the present day and future for this region. The climate of South Asia means it is one of the most irrigated agricultural regions in the world, therefore pressures on water resource affecting the availability of water for irrigation could adversely affect crop yields and therefore food production. In this paper we present the first 25 km resolution regional climate projections of river flow for the South Asia region. ERA-Interim, together with two global climate models (GCMs), which represent the present day processes, particularly the monsoon, reasonably well are downscaled using a regional climate model (RCM) for the periods; 1990-2006 for ERA-Interim and 1960-2100 for the two GCMs. The RCM river flow is routed using a river-routing model to allow analysis of present day and future river flows through comparison with river gauge observations, where available. In this analysis we compare the river flow rate for 12 gauges selected to represent the largest river basins for this region; Ganges, Indus and Brahmaputra basins and characterize the changing conditions from east to west across the Himalayan arc. Observations of precipitation and runoff in this region have large or unknown uncertainties, are short in length or are outside the simulation period, hindering model development and validation designed to improve understanding of the water cycle for this region. In the absence of robust observations for South Asia, a downscaled ERA-Interim RCM simulation provides a

  13. The impact of river restoration on the water quality of the surface water and groundwater in an Alpine catchment.

    NASA Astrophysics Data System (ADS)

    Chittoor Viswanathan, V.; Schirmer, M.

    2012-04-01

    The importance of river restoration projects can only be realized upon evaluating their success or failure in a region mainly with regards to water quality, ecological adaptations and flood mitigation. The Thur catchment in North eastern Switzerland is chosen as the study area. The water quality along the entire river reach (with the corresponding groundwater monitoring wells) will be analyzed with regard to the existing land use and a comparison shall be made with the water quality in the restored river sections of the river. A restored river section at Niederneunforn has been heavily monitored as part of the RECORD project and this data shall be vital for the present work. The water quality changes are to be observed by relating to some of the basic parameters like pH, electrical conductivity, dissolved oxygen, total organic carbon (TOC), total inorganic carbon (TIC) , the concentration of ions like chloride, nitrate, nitrite, ortho-phosphate, ammonium and calcium. These are to be measured in both the surface and the groundwater upstream and downstream of the restored section in the study river. Both long-term monitoring as well as localized water sampling campaigns are planned as part of the study. Use of the stable isotopes of oxygen and nitrogen is to be done to trace the possible sources of contamination in the river reach. This study shall aim to answer the following questions: 1. What are the diurnal and seasonal water quality changes in the Thur river; upstream and downstream of the restored section? 2. Are there any links between the different water quality parameters and how does the restored section influence these links? 3. How does the water quality change from the river to the groundwater (due to the recharge) between the restored and the unrestored river sections? 4. How does the land use in the catchment affect / alter the water quality in the river? -Is there high pollutant load from a particular waste water treatment or more agricultural runoff

  14. Late Quaternary stream piracy and strath terrace formation along the Belle Fourche and lower Cheyenne Rivers, South Dakota and Wyoming

    USGS Publications Warehouse

    Stamm, John F.; Hendricks, Robert R.; Sawyer, J. Foster; Mahan, Shannon; Zaprowski, Brent J.; Geibel, Nicholas M.; Azzolini, David C.

    2013-01-01

    Stream piracy substantially affected the geomorphic evolution of the Missouri River watershed and drainages within, including the Little Missouri, Cheyenne, Belle Fourche, Bad, and White Rivers. The ancestral Cheyenne River eroded headward in an annular pattern around the eastern and southern Black Hills and pirated the headwaters of the ancestral Bad and White Rivers after ~ 660 ka. The headwaters of the ancestral Little Missouri River were pirated by the ancestral Belle Fourche River, a tributary to the Cheyenne River that currently drains much of the northern Black Hills. Optically stimulated luminescence (OSL) dating techniques were used to estimate the timing of this piracy event at ~ 22–21 ka. The geomorphic evolution of the Cheyenne and Belle Fourche Rivers is also expressed by regionally recognized strath terraces that include (from oldest to youngest) the Sturgis, Bear Butte, and Farmingdale terraces. Radiocarbon and OSL dates from fluvial deposits on these terraces indicate incision to the level of the Bear Butte terrace by ~ 63 ka, incision to the level of the Farmingdale terrace at ~ 40 ka, and incision to the level of the modern channel after ~ 12–9 ka. Similar dates of terrace incision have been reported for the Laramie and Wind River Ranges. Hypothesized causes of incision are the onset of colder climate during the middle Wisconsinan and the transition to the full-glacial climate of the late-Wisconsinan/Pinedale glaciation. Incision during the Holocene of the lower Cheyenne River is as much as ~ 80 m and is 3 to 4 times the magnitude of incision at ~ 63 ka and ~ 40 ka. The magnitude of incision during the Holocene might be due to a combined effect of three geomorphic processes acting in concert: glacial isostatic rebound in lower reaches (~ 40 m), a change from glacial to interglacial climate, and adjustments to increased watershed area resulting from piracy of the ancestral headwaters of the Little Missouri River.

  15. Developing a simplified river landscape assessment model: examples from the Chungkang and Touchien rivers, Taiwan.

    PubMed

    Chen, Shiang-Yuarn; Lin, Jen-Yang

    2007-04-01

    Currently, river landscape evaluations cannot be conducted by the general public, due to their lack of professional training. However, consulting professionals is time consuming and costly. The research conducted addresses both problems by (1) developing suitable criteria for assessing river environments, and (2) formulating a strategy for using the proposed criteria, thereby creating an effective method for river management by non-professionals. This research was carried out, in accordance with Visual Resource Management theory, at 12 survey sites along the ChungKang River. The landscape quality sequences acquired were then evaluated using a revised and simplified assessment model. The same process was repeated on the Touchien River to verify its feasibility. This research developed both specific criteria as well a method for evaluating river landscapes, which can be employed by non-professional river project managers. Ultimately, the aim of this research is to develop and promote sustainable river resource management.

  16. Assessing Summer and Fall Chinook Salmon Restoration in the Upper Clearwater River and Principal Tributaries, 1994 Annual Report.

    SciTech Connect

    Arnsberg, Billy D.; Statler, David P.

    1995-08-01

    This is the first annual report of a five year study to assess summer and fall chinook salmon restoration potential in the upper Clearwater River and principal tributaries, Salmon, Grande Ronde, and Imnaha Rivers. During 1994, the authors focused primarily on assessing water temperatures and spawning habitat in the upper Clearwater River and principal tributaries. Water temperature analysis indicated a colder temperature regime in the upper Clearwater River above the North Fork Clearwater River confluence during the winter as compared to the lower Clearwater. This was due to warm water releases from Dworshak Reservoir on the North Fork moderating temperatures in the lower Clearwater River. Thermal temperature unit analysis and available literature suggest a 75% survival threshold level may be anticipated for chinook salmon egg incubation if spawning would occur by November 1 in the upper Clearwater River. Warm water upwelling in historic summer and fall chinook spawning areas may result in increased incubation survivals and will be tested in the future. The authors observed a total of 37 fall chinook salmon redds in the Clearwater River subbasin. They observed 30 redds in the mainstem Clearwater below the North Fork Clearwater River confluence and seven redds in the North Fork Clearwater River. No redds were observed in the South Fork Clearwater, Middle Fork Clearwater, or Selway Rivers. They observed one fall chinook salmon redd in the Salmon River. They recovered 10 fall chinook salmon carcasses in the Clearwater River to obtain biological measurements and to document hatchery contribution to spawning. Unseasonably high and cold Dworshak Dam releases coinciding with early juvenile fall chinook salmon rearing in the lower Clearwater River may be influencing selective life history traits including growth, smolt development, outmigration timing, behavior, and could be directly affecting survival. During July 1994, discharges from Dworshak Dam increased from a

  17. An ensemble-based reanalysis approach for estimating river bathymetry from the upcoming SWOT mission

    NASA Astrophysics Data System (ADS)

    Yoon, Y.; Durand, M. T.; Merry, C. J.; Clark, E.; Alsdorf, D. E.

    2011-12-01

    In spite of the critical role of river discharge in land surface hydrology, global gauging networks are sparse and even have been in decline. Over the past decade, researchers have been trying to better estimate river discharge using remote sensing techniques to complement the existing in-situ gage networks. The upcoming Surface Water and Ocean Topography (SWOT) mission will directly provide simultaneous spatial mapping of inundation area (A) and inland water surface elevation (WSE) data (i.e., river, lakes, wetlands, and reservoirs), both temporally (dh/dt) and spatially (dh/dx), with the Ka-band Radar INterferometer (KaRIN). With these observations, the SWOT mission will provide the measurements of water storage changes in terrestrial surface water bodies. However, because the SWOT will measure WSE, not the true depth to the river bottom, the cross section channel bathymetry will not be fully measured. Thus, estimating bathymetry is important in order to produce accurate estimates of river discharge from the SWOT data. In previous work, a local ensemble Kalman filter (LEnKF) was used to estimate the river bathymetry, given synthetic SWOT observations and WSE predictions by the LISFLOOD-FP hydrodynamic model. However, the accuracy of river bathymetry was highly affected by the severe bias of boundary inflows due to the mathematical relationship for the assimilation. The bias in model is not accounted for the data assimilation. Here, we focus on correcting the forecast bias for the LEnKF scheme to result in the improvement of river bathymetry estimates. To correct the forecast bias and improve the accuracy, we combined the LEnKF scheme with continuity and momentum equations. To evaluate the reanalysis approach, the error of bathymetry was evaluated by comparing with the true value and previous work. In addition, we examined the sensitivity to the bathymetry estimate for estimating the river discharge.

  18. Water Quality and Streamflow of the Indian River, Sitka, Alaska, 2001-02

    USGS Publications Warehouse

    Neal, Edward J.; Brabets, Timothy P.; Frenzel, Steven A.

    2004-01-01

    The Indian River Basin, located near Sitka Alaska, drains an area of 12.3 square miles. This watershed is an important natural resource of Sitka National Historic Park. At the present time, the watershed faces possible development on large tracts of private land upstream of the park that could affect the water quality of Indian River. Due to this concern, a study was conducted cooperatively with the National Park Service. The approach was to examine the water quality of the Indian River in the upper part of the watershed where no development has occurred and in the lower part of the basin where development has taken place. Measurements of pH, water temperature, and dissolved oxygen concentrations of the Indian River were within acceptable ranges for fish survival. The Indian River is calcium bicarbonate type water with a low buffering capacity. Concentrations of dissolved ions and nutrients generally were low and exhibited little variation between the two study sites. Analysis of bed sediment trace element concentrations at both sampling sites indicates the threshold effect concentration was exceeded for arsenic, chromium, copper, nickel, and zinc; while the probable effect concentration was exceeded by arsenic, chromium and nickel. However, due to relatively large amounts of organic carbon present in the bed sediments, the potential toxicity from trace elements is low. Discharge in the Indian River is typical of coastal southeast Alaska streams where low flows generally are in late winter and early spring and greater flows are during the wetter fall months. Alaska Department of Fish and Game has established instream flow reservations on the lower 2.5 miles of the Indian River. Discharge data indicate minimum flow requirements were not achieved during 236 days of the study period. Natural low flows are frequently below the flow reservations, but diversions resulted in flow reservations not being met a total of 140 days. Thirty-five algae species were identified

  19. Water-quality conditions near the confluence of the Snake and Boise Rivers, Canyon County, Idaho

    USGS Publications Warehouse

    Wood, Molly S.; Etheridge, Alexandra

    2011-01-01

    Total Maximum Daily Loads (TMDLs) have been established under authority of the Federal Clean Water Act for the Snake River-Hells Canyon reach, on the border of Idaho and Oregon, to improve water quality and preserve beneficial uses such as public consumption, recreation, and aquatic habitat. The TMDL sets targets for seasonal average and annual maximum concentrations of chlorophyll-a at 14 and 30 micrograms per liter, respectively. To attain these conditions, the maximum total phosphorus concentration at the mouth of the Boise River in Idaho, a tributary to the Snake River, has been set at 0.07 milligrams per liter. However, interactions among chlorophyll-a, nutrients, and other key water-quality parameters that may affect beneficial uses in the Snake and Boise Rivers are unknown. In addition, contributions of nutrients and chlorophyll-a loads from the Boise River to the Snake River have not been fully characterized. To evaluate seasonal trends and relations among nutrients and other water-quality parameters in the Boise and Snake Rivers, a comprehensive monitoring program was conducted near their confluence in water years (WY) 2009 and 2010. The study also provided information on the relative contribution of nutrient and sediment loads from the Boise River to the Snake River, which has an effect on water-quality conditions in downstream reservoirs. State and site-specific water-quality standards, in addition to those that relate to the Snake River-Hells Canyon TMDL, have been established to protect beneficial uses in both rivers. Measured water-quality conditions in WY2009 and WY2010 exceeded these targets at one or more sites for the following constituents: water temperature, total phosphorus concentrations, total phosphorus loads, dissolved oxygen concentration, pH, and chlorophyll-a concentrations (WY2009 only). All measured total phosphorus concentrations in the Boise River near Parma exceeded the seasonal target of 0.07 milligram per liter. Data collected

  20. Longitudinal dispersion in vegetated rivers with stochastic flows

    NASA Astrophysics Data System (ADS)

    Tealdi, S.; Camporeale, C.; Perucca, E.; Ridolfi, L.

    2010-05-01

    Longitudinal dispersion is one of the most important transport processes in fluvial ecosystems. It affects the transport of chemicals, nutrients, seeds, and wood debris along a river. The focus of this work is on the impact of riparian vegetation on the dispersion coefficient. The investigation considers stochastic forcing due to the river discharge randomness and its interplay with vegetation dynamics. A stochastic bio-hydrodynamical model is proposed and the probability distribution of the dispersion coefficient is obtained. The model allows one to elucidate the influence of (i) the vegetation characteristics, (ii) the probabilistic structure of the discharge time series, and (iii) the hydraulic characteristics of the transect. The work demonstrates the high variability of dispersion coefficients and the remarkable impact of riparian vegetation when medium/high discharges flow.

  1. Mississippi River

    Atmospheric Science Data Center

    2014-05-15

    article title:  Spring Flooding on the Mississippi     ... to melt and the Wapsipinicon River was 52 centimeters above flood stage at De Witt, Iowa (between Clinton and Davenport). By mid-April ... slightly below the level reached in the record-setting flood of 1993. MISR was built and is managed by NASA's Jet Propulsion ...

  2. Knowledge River

    ERIC Educational Resources Information Center

    Berry, John N., III

    2004-01-01

    One of the most promising of all diversity initiatives in library and information studies (LIS) is Knowledge River (KR) at the School of Information Resources and Library Science (SIRLS) at the University of Arizona, Tucson. Created and directed by Patricia A. Tarin, the program has already recruited some 42 students into the profession, 20 of…

  3. Niger River

    Atmospheric Science Data Center

    2013-04-15

    ... third largest river in Africa, the Niger, forms an inland delta in central Mali. This Multi-angle Imaging SpectroRadiometer (MISR) image ... the region as it appears after the rainy season, when the delta is flooded. The image covers an area measuring about 400 kilometers x 450 ...

  4. Nitrogen and phosphorus in the Upper Mississippi River: Transport, processing, and effects on the river ecosystem

    USGS Publications Warehouse

    Houser, J.N.; Richardson, W.B.

    2010-01-01

    Existing research on nutrients (nitrogen and phosphorus) in the Upper Mississippi River (UMR) can be organized into the following categories: (1) Long-term changes in nutrient concentrations and export, and their causes; (2) Nutrient cycling within the river; (3) Spatial and temporal patterns of river nutrient concentrations; (4) Effects of elevated nutrient concentrations on the river; and (5) Actions to reduce river nutrient concentrations and flux. Nutrient concentration and flux in the Mississippi River have increased substantially over the last century because of changes in land use, climate, hydrology, and river management and engineering. As in other large floodplain rivers, rates of processes that cycle nitrogen and phosphorus in the UMR exhibit pronounced spatial and temporal heterogeneity because of the complex morphology of the river. This spatial variability in nutrient processing creates clear spatial patterns in nutrient concentrations. For example, nitrate concentrations generally are much lower in off-channel areas than in the main channel. The specifics of in-river nutrient cycling and the effects of high rates of nutrient input on UMR have been less studied than the factors affecting nutrient input to the river and transport to the Gulf of Mexico, and important questions concerning nutrient cycling in the UMR remain. Eutrophication and resulting changes in river productivity have only recently been investigated the UMR. These recent studies indicate that the high nutrient concentrations in the river may affect community composition of aquatic vegetation (e. g., the abundance of filamentous algae and duckweeds), dissolved oxygen concentrations in off-channel areas, and the abundance of cyanobacteria. Actions to reduce nutrient input to the river include changes in land-use practices, wetland restoration, and hydrological modifications to the river. Evidence suggests that most of the above methods can contribute to reducing nutrient concentration in

  5. A study on the applicability of the ecosystem model on water quality prediction in urban river outer moats of Yedo Castle, Nihonbashi River

    NASA Astrophysics Data System (ADS)

    Kakinuma, Daiki; Tsushima, Yuki; Ohdaira, Kazunori; Yamada, Tadashi

    2015-04-01

    The objective of the study is to elucidate the waterside environment in the outer moats of Yedo Castle and the downstream of Nihonbashi River in Tokyo. Scince integrated sewage system has been installed in the area around the outer moats of Yedo Castle and the Nihon River basin, when rainfall exceeds more than the sewage treatment capacity, overflowed untreated wastewater is released into the moats and the river. Because the moats is a closed water body, pollutants are deposited to the bottom without outflowing. While reeking offensive odors due to the decomposition, blue-green algae outbreaks affected by the residence time and eluted nutrient causes problems. Scince the Nihonbashi River is a typical tidal river in urban area, the water pollution problems in the river is complicated. This study clarified the characteristics of the water quality in terms of dissolved oxygen saturation through on-site observations. In particular, dissolved oxygen saturation in summer, it is clarified that variations from a supersaturated state due to the variations of horizontal insolation intensity and water temperature up to hypoxic water conditions in the moats. According to previous studies on the water quality of Nihonbashi River, it is clarified that there are three types of variations of dissolved oxygen which desided by rainfall scale. The mean value of dissolved oxygen saturation of all layers has decreased by about 20% at the spring tide after dredging, then it recoveres gradually and become the value before dredging during about a year. Further more, in places where sewage inflows, it is important to developed a ecosystem medel and the applicability of the model. 9 variables including cell quota (intracellular nutrients of phytoplankton) of phosphorus and nitrogen with considerring the nitrification of ammonia nitrogen are used in the model. This model can grasp the sections (such as oxygen production by photosynthesis of phytoplankton, oxygen consumption by respiration of

  6. Manganese oxidation model for rivers

    USGS Publications Warehouse

    Hess, Glen W.; Kim, Byung R.; Roberts, Philip J.W.

    1989-01-01

    The presence of manganese in natural waters (>0.05 mg/L) degrades water-supply quality. A model was devised to predict the variation of manganese concentrations in river water released from an impoundment with the distance downstream. The model is one-dimensional and was calibrated using dissolved oxygen, biochemical oxygen demand, pH, manganese, and hydraulic data collected in the Duck River, Tennessee. The results indicated that the model can predict manganese levels under various conditions. The model was then applied to the Chattahoochee River, Georgia. Discrepancies between observed and predicted may be due to inadequate pH data, precipitation of sediment particles, unsteady flow conditions in the Chattahoochee River, inaccurate rate expressions for the low pH conditions, or their combinations.

  7. PCBs in the Harlem River

    NASA Astrophysics Data System (ADS)

    Wang, J.

    2012-12-01

    Polychlorinated biphenyls (PCBs) are persistent, toxic and bioaccumulated contaminants of great environmental concern. PCB is a tracer of wastewater, stormwater and CSOs inputs; PCBs contamination of fish is a main environmental concern for the Harlem River. PCBs in the Harlem River are from combined sewer overflows (CSOs), stormwater runoff, wastewater, as well as upper Hudson GE (General Electric at Fort Edward)'s release. PCBs affect human health mostly from contaminated fish consumption. Many research focused on PCBs in the Hudson River and New York/New Jersey Harbor. However, PCBs source, transport and environmental impact in the Harlem River-a natural straight that connects the Hudson River and the East River, had not been well studied. In this research, water sample were collected from the Harlem River and analyzed PCBs by HR GC/MS (High resolution gas chromatography mass spectrophotometer). Preliminary results showed that certain PCBs congeners in the water column. Results also indicated that nutrients (phosphorus and ammonia) as well as bacteria levels exceeded EPA standards: Total phosphorus-10μg/L, total nitrogen-0.38mg/L; E.Coli-126 MPN/100ml, Enterococcus- 104MPN/100ml, Fecal Coliform-200 MPN/100ml. This research is under process, and more results could give further detail in near future. This research will help improve water quality of the Harlem River, improve environmental health and raise environmental awareness.SO tank Nutrient and bacterial levels of selected sites in the Harlem RiverCSO: Combined Sewer OverflowWWTP: Waste Water Treatment Plant

  8. Surveying of morphological variations in estuarine Nyband River

    NASA Astrophysics Data System (ADS)

    Ghobadi-Bistooni, S.; Ershadi, C.

    2009-04-01

    Rivers estuary in aspect of ecological and morphological is very sensitive in coastal zones. This area can affect from human activities and these activities have direct effective on natural state of these area. There for, overall aim of this work is steady on development of this coastal area and thus, it is investigated the morphological and sedimentation mechanism in estuarine area. For this case study, area is limited (27°11'NL ; 56°19'EL), begin from Genu mountains in southern parts of Iran and pass from mid of Bandar Abbas city and in final ends to north of Persian Gulf. There were some physical variations in this estuarine area of Nyband River due to human activities. These variations include: fixing the banks, Jetty break water in near of estuary and recently sealing the bed bottom of river and building of bridge. A numerical program was used for analysis this hydrodynamic and sediment condition. This result compares with field data for evaluation of the numerical analysis. Also, the aero photographical document in past decade was prepared for surveying morphological variations. For this purpose, the GIS (ARCVIEW) was used and finally, the effect of the human activities, such as building of new structure, on morphology of river was investigated.

  9. The River Mondego terraces at the Figueira da Foz coastal area (western central Portugal): Geomorphological and sedimentological characterization of a terrace staircase affected by differential uplift and glacio-eustasy

    NASA Astrophysics Data System (ADS)

    Ramos, Anabela M.; Cunha, Pedro P.; Cunha, Lúcio S.; Gomes, Alberto; Lopes, Fernando C.; Buylaert, Jan-Pieter; Murray, Andrew S.

    2012-09-01

    A geomorphological and sedimentological characterization of the River Mondego terraces in the Figueira da Foz coastal area, Portugal, is presented. The relief is dominated by a Pliocene a marine sandy unit ~ 10-15 m thick, reaching ~ 250 m a.s.l., that covers a shore platform surface. The River Mondego has incised into the Pliocene relief and its long drainage evolution is recorded within a series of inset river terrace landforms. These river terraces are better preserved on the right-hand (northern) bank, where they form a staircase developed against the uplifted Serra da Boa Viagem structure. A set of five river terraces, represented by sedimentary deposits or erosional straths, are identified, namely: T1 at 128-125 m; T2 at 101-90 m; T3 at 70-60 m; T4 at 29-24 m; T5 at 11-10 m a.s.l. Some luminescence dating ages were obtained from the river terrace deposits: > 390 ka from the middle of T4; > 170 ka from the top of T4; ~ 120 ka from the base of T5; ~ 109 ka from T5 (average age for three samples); and 53 ± 3 ka from a colluvium at 35 m a.s.l. Some differences in altitude of the uppermost sedimentary unit and of the terraces are here interpreted as resulting from vertical displacements of active faults during the Quaternary. The main tectonic structure is the WNW-ESE trending Quiaios fault, responsible for the regional tilting towards SW. Other probably active faults and tectonic lineaments trend NNW-SSE to N-S, NNE-SSW to NE-SW and WNW-ESE. This study reports a long-term uplift rate of 0.004-0.055 m/ka for the last 3.6 Ma, but 0.017-0.118 m/ka for the last ~ 1.8 Ma (using as references, respectively, the base and the surface of the uppermost sedimentary unit). The facies associations that characterize the older terrace deposits (T1 and T2) consist of poorly sorted fluvial sandy-gravels and silts, but also some colluvium at the top of each terrace. The younger terraces (T3, T4 and T5) show better developed sedimentary structures and less sedimentary matrix; the

  10. Channel-conveyance capacity, channel change, and sediment transport in the lower Puyallup, White, and Carbon Rivers, western Washington

    USGS Publications Warehouse

    Czuba, Jonathan A.; Czuba, Christiana R.; Magirl, Chistopher S.; Voss, Frank D.

    2010-01-01

    -conveyance capacity was the White River between R Street Bridge and the Lake Tapps return, a reach affected by recent flooding. Conveyance capacity also decreased in sections of the Puyallup River. Conveyance capacity was mostly unchanged along other study reaches. Bedload transport was simulated throughout the entire river network and consistent with other observations and analyses, the hydraulic model showed that the upper Puyallup and White Rivers tended to accumulate sediment. Accuracy of the bedload-transport modeling, however, was limited due to a scarcity of sediment-transport data sets from the Puyallup system, mantling of sand over cobbles in the lower Puyallup and White Rivers, and overall uncertainty in modeling sediment transport in gravel-bedded rivers. Consequently, the output results from the model were treated as more qualitative in value, useful in comparing geomorphic trends within different river reaches, but not accurate in producing precise predictions of mass of sediment moved or deposited. The hydraulic model and the bedload-transport component were useful for analyzing proposed river-management options, if surveyed cross sections adequately represented the river-management site and proposed management options. The hydraulic model showed that setback levees would provide greater flood protection than gravel-bar scalping after the initial project construction and for some time thereafter, although the model was not accurate enough to quantify the length of time of the flood protection. The greatest hydraulic benefit from setback levees would be a substantial increase in the effective channel-conveyance area. By widening the distance between levees, the new floodplain would accommodate larger increases in discharge with relatively small incremental increases in stage. Model simulation results indicate that the hydraulic benefit from a setback levee also would be long-lived and would effectively compensate for increased deposition within the setback reach

  11. Mercury in the Mackenzie River delta and estuary: concentrations and fluxes during open-water conditions.

    PubMed

    Graydon, Jennifer A; Emmerton, Craig A; Lesack, Lance F W; Kelly, Erin N

    2009-04-01

    Estimates of mercury (Hg) loadings to the Arctic Ocean from circumpolar rivers have not considered biogeochemical changes that occur when river water is temporarily stored in large deltas (delta effect). There are also few data describing Hg changes across the freshwater-saltwater transition zone (FSTZ) of these rivers. We assessed temporal changes in unfiltered total mercury (THg) and methylmercury (MeHg) concentrations during open-water 2004 in the Mackenzie River upstream of the Mackenzie River delta, and in 6 floodplain lakes across an elevation gradient. These data were used to calculate Hg fluxes from the Mackenzie River and to evaluate a delta effect on Hg using an estimate of delta river water storage and a mixing analysis. Mean THg concentrations were highest in river water (9.17+/-5.51 ng/L) and decreased up the lake elevation gradient. Mean MeHg concentrations were highest in lakes periodically connected to the river (0.213+/-0.122 ng/L) and MeHg concentrations in elevated lakes showed a mid-summer peak. Results from the mixing analysis showed that the delta effect may be large enough to affect Hg loadings to the Arctic Ocean. THg concentrations exiting the delta (10.2 ng/L) were 16% lower than those entering (12.1 ng/L), whereas MeHg showed little change. We calculated 2.5-month (open-water) THg and MeHg fluxes from the Mackenzie River of 1208 and 8.4 kg. These fluxes are similar in magnitude to previous annual estimates in the arctic literature suggesting that previously published annual Hg fluxes from the Mackenzie River may be large underestimates. We also assessed changes in Mackenzie River water THg and MeHg concentrations as it crossed the FSTZ during an open-water cruise. THg decreased non-conservatively across the estuary from 3.8-0.6 ng/L, possibly due to mixing and particle settling. MeHg concentrations were variable and near detection. Our results show that the Mackenzie River estuary is a dynamic environment and may have important controls

  12. Decreased fish diversity found near marble industry effluents in River Barandu, Pakistan.

    PubMed

    Mulk, Shahi; Korai, Abdul Latif; Azizullah, Azizullah; Khattak, Muhammad Nasir Khan

    2016-01-01

    In a recently published study we observed that effluents from marble industry affected physicochemical characteristics of River Barandu in District Buner, Pakistan. These changes in water quality due to marble effluents may affect fish community. The present study was therefore conducted to evaluate the impacts of marble industry effluents on fish communities in River Barandu using abundance, richness, diversity and evenness of fish species as end point criteria. The fish samples were collected by local fishermen on monthly basis from three selected sites (upstream, effluents/industrial, and downstream sites). During the study period, a total of 18 fish species were found belonging to 4 orders, 5 families and 11 genera. The Cyprinidae was observed to be the dominant family at all the three selected sites. Lower abundance and species diversity was observed at the industrial (22%) and downstream sites (33%) as compared to the upstream site (45%). Effluents of marble industry were associated with lower abundance of species in River Barandu. It is recommended that industries should be shifted away from the vicinity of river and their effluents must be treated before discharging to prevent further loss of fish abundance and diversity in the River.

  13. Long-term changes in mercury concentrations in fish from the middle Savannah River.

    PubMed

    Paller, M H; Littrell, James W

    2007-09-01

    Total mercury levels were measured in largemouth bass (Micropterus salmoides), "sunfish" (Lepomis spp.), and "catfish" (primarily Ameiurus spp. and Ictalurus punctatus) from 1971 to 2004 in the middle Savannah River (river km 191 to 302), which drains the coastal plain of the southeastern U.S. Total mercury concentrations were higher in largemouth bass (overall mean of 0.55 mg/kg from 1971 to 2004), a piscivorous (trophic level 4) species than in the other taxa (means of 0.22-0.26 mg/kg), but temporal trends were generally similar among taxa. Mercury levels were highest in 1971 but declined over the next 10 years due to the mitigation of point source industrial pollution. Mercury levels in fish began to increase in the 1980s as a likely consequence of mercury inputs from tributaries and associated wetlands where mercury concentrations were significantly elevated in water and fish. Mercury levels in Savannah River fish decreased sharply in 2001-2003 coincident with a severe drought in the Savannah River basin, but returned to previous levels in 2004 with the resumption of normal precipitation. Regression models showed that mercury levels in fish changed significantly over time and were affected by river discharge. Mercury levels in Savannah River fish were only slightly lower in 2004 (0.3 to 0.8 mg/kg) than in 1971 (0.4 to 1.0 mg/kg) despite temporal changes during the intervening years.

  14. LONG-TERM CHANGES IN MERCURY CONCENTRATIONS IN FISH FROM THE MIDDLE SAVANNAH RIVER

    SciTech Connect

    Paller, M; Bill Littrell, B

    2007-01-02

    Total mercury levels were measured in largemouth bass (Micropterus salmoides), ''sunfishes'' (Lepomis spp)., and ''catfish'' (primarily Ameiurus spp.) from 1971 to 2004 in the middle reaches of the Savannah River, which drains the coastal plain of the southeastern U.S. Mercury levels were highest in 1971 but declined over the next ten years due to the mitigation of point sources of industrial pollution. Mercury levels began to increase in the 1980s as a possible consequence of mercury inputs from tributaries and associated wetlands where mercury concentrations were significantly elevated in water and fish. Mercury levels in Savannah River fish decreased sharply in 2001-2003 coincident with a severe drought in the Savannah River basin, but returned to previous levels in 2004 with the resumption of normal precipitation. Regression models showed that mercury levels in Savannah River fish changed significantly over time and were affected by river discharge. Despite temporal changes, there was little overall difference in Savannah River fish tissue mercury levels between 1971 and 2004.

  15. Detection of solar dimming and brightening effects on Northern Hemisphere river flow

    NASA Astrophysics Data System (ADS)

    Gedney, N.; Huntingford, C.; Weedon, G. P.; Bellouin, N.; Boucher, O.; Cox, P. M.

    2014-11-01

    Anthropogenic aerosols in the atmosphere have the potential to affect regional-scale land hydrology through solar dimming. Increased aerosol loading may have reduced historical surface evaporation over some locations, but the magnitude and extent of this effect is uncertain. Any reduction in evaporation due to historical solar dimming may have resulted in an increase in river flow. Here we formally detect and quantify the historical effect of changing aerosol concentrations, via solar radiation, on observed river flow over the heavily industrialized, northern extra-tropics. We use a state-of-the-art estimate of twentieth century surface meteorology as input data for a detailed land surface model, and show that the simulations capture the observed strong inter-annual variability in runoff in response to climatic fluctuations. Using statistical techniques, we identify a detectable aerosol signal in the observed river flow both over the combined region, and over individual river basins in Europe and North America. We estimate that solar dimming due to rising aerosol concentrations in the atmosphere around 1980 led to an increase in river runoff by up to 25% in the most heavily polluted regions in Europe. We propose that, conversely, these regions may experience reduced freshwater availability in the future, as air quality improvements are set to lower aerosol loading and solar dimming.

  16. Characterizing a December 2005 density current event in the Chicago River, Chicago, Illinois

    USGS Publications Warehouse

    Garcia, C.M.; Jackson, P.R.; Oberg, K.A.; Johnson, K.K.; Garcia, M.H.

    2007-01-01

    During the winter months, the Chicago River in Chicago, Illinois is subject to bi-directional flows, and density currents are thought to be responsible for these flow variations. This paper presents detailed field measurements using three acoustic Doppler current profiler instruments and simultaneous water-quality measurements made during December 2005. Observations indicate that the formation of density currents within the Chicago River and density differences are mostly due to salinity differences between the North Branch and the main stem of the Chicago River, whereas temperature difference does not appreciably affect the creation of density currents. Sources of higher water temperature, conductivity, and salinity values should be addressed in future studies. ?? 2007 ASCE.

  17. Assessment of hydraulic fish habitat condition using integrated toolkit: a case study of the Geum river basin, Republic of Korea.

    PubMed

    Park, Sangyoung; Kim, Jeongkon; Ko, Ick Hwan; Arthington, Angela; Jones, Gary; Yum, Kyung Taek

    2010-01-01

    Artificial changes of rivers, including construction and operation of dams, inevitably lead to physical and ecological changes throughout waterways and their floodplains. In this study, a conceptual model coupled with integrated numerical modeling is presented for hydraulic fish habitat assessment of the Geum River basin, Republic of Korea. Based on the major events which might have affected the ecological system, a conceptual model was formulated to guide desktop and field studies, modeling and scenario evaluations. The result of hydraulic fish habitat assessment indicated that the construction of the Daecheong Multipurpose Dam (DMD) in the Geum River basin has altered flow magnitudes and reduced the river's flow variability. Changes are evident in the magnitude of medium and small flows and the river experiences increased low flows during the dry season. Black shiner, an endangered fish species in Korea, was selected and analyzed to explore relationships between flow regime change by dams and changes to its preferred habitats. As a result, fewer sensitive riffle-benthic species were observed in the reaches downstream of DMD due to the reduction of suitable habitat conditions such as riffle-pool sequences. The proposed conceptual model and integrated toolkit would allow river managers to isolate the physical and biological effects associated with dam operation and could be useful for developing river management strategies.

  18. Assessment of groundwater input and water quality changes impacting natural vegetation in the Loxahatchee River and floodplain ecosystem, Florida

    USGS Publications Warehouse

    Orem, William H.; Swarzenski, Peter W.; McPherson, Benjamin F.; Hedgepath, Marion; Lerch, Harry E.; Reich, Christopher; Torres, Arturo E.; Corum, Margo D.; Roberts, Richard E.

    2007-01-01

    The Loxahatchee River and Estuary are small, shallow, water bodies located in southeastern Florida. Historically, the Northwest Branch (Fork) of the Loxahatchee River was primarily a freshwater system. In 1947, the river inlet at Jupiter was dredged for navigation and has remained permanently open since that time. Drainage patterns within the basin have also been altered significantly due to land development, road construction (e.g., Florida Turnpike), and construction of the C-18 and other canals. These anthropogenic activities along with sea level rise have resulted in significant adverse impacts on the ecosystem over the last several decades, including increased saltwater encroachment and undesired vegetation changes in the floodplain. The problem of saltwater intrusion and vegetation degradation in the Loxahatchee River may be partly induced by diminished freshwater input, from both surface water and ground water into the River system. The overall objective of this project was to assess the seasonal surface water and groundwater interaction and the influence of the biogeochemical characteristics of shallow groundwater and porewater on vegetation health in the Loxahatchee floodplain. The hypothesis tested are: (1) groundwater influx constitutes a significant component of the overall flow of water into the Loxahatchee River; (2) salinity and other chemical constituents in shallow groundwater and porewater of the river floodplain may affect the distribution and health of the floodplain vegetation.

  19. Hydrologic linkages between a climate oscillation, river flows, growth, and wood Δ13C of male and female cottonwood trees.

    PubMed

    Rood, Stewart B; Ball, Deborah J; Gill, Karen M; Kaluthota, Sobadini; Letts, Matthew G; Pearce, David W

    2013-05-01

    To investigate climatic influence on floodplain trees, we analysed interannual correspondences between the Pacific Decadal Oscillation (PDO), river and groundwater hydrology, and growth and wood (13)C discrimination (Δ(13)C) of narrowleaf cottonwoods (Populus angustifolia) in a semi-arid prairie region. From the Rocky Mountain headwaters, river discharge (Q) was coordinated with the PDO (1910-2008: r(2) = 0.46); this pattern extended to the prairie and was amplified by water withdrawal for irrigation. Floodplain groundwater depth was correlated with river stage (r(2) = 0.96), and the cottonwood trunk basal area growth was coordinated with current- and prior-year Q (1992-2008: r(2) = 0.51), increasing in the mid-1990s, and decreasing in 2000 and 2001. Annual Δ(13)C decreased during low-flow years, especially in trees that were higher or further from the river, suggesting drought stress and stomatal closure, and male trees were more responsive than females (-0.86 versus -0.43‰). With subsequently increased flows, Δ(13)C increased and growth recovered. This demonstrated the linkages between hydroclimatic variation and cottonwood ecophysiology, and we conclude that cottonwoods will be vulnerable to drought from declining river flows due to water withdrawal and climate change. Trees further from the river could be especially affected, leading to narrowing of floodplain forests along some rivers.

  20. The effect of channel shape, bed morphology, and shipwrecks on flow velocities in the Upper St. Clair River

    USGS Publications Warehouse

    Czuba, Jonathan A.; Oberg, Kevin; Best, Jim; Parsons, Daniel R.

    2009-01-01

    In the Great Lakes of North America, the St. Clair River is the major outlet of Lake Huron and conveys water to Lake St. Clair which then flows to Lake Erie. One major topic of interest is morphological change in the St. Clair River and its impact on water levels in the Upper Great Lakes and connecting channel flows. A combined multibeam echosounder (MBES) bathymetric survey and acoustic Doppler current profiler (ADCP) flow survey of the outlet of Lake Huron and the Upper St. Clair River was conducted July 21 – 25, 2008. This paper presents how channel morphology and shipwrecks affect the flow in the Upper St. Clair River. The river is most constricted at the Blue Water Bridge near Port Huron, Michigan, with water velocities over 2 ms-1 for a flow of 5,200 m3s-1. Downstream of this constriction, the river flows around a bend and expands creating a large recirculation zone along the left bank due to flow separation. This recirculation zone reduces the effective channel width, and thus increases flow velocities to over 2 ms-1 in this region. The surveys reveal several shipwrecks on the bed of the St. Clair River, which possess distinct wakes in their flow velocity downstream of the wrecks. The constriction and expansion of the channel, combined with forcing of the flow by bed topography, initiates channel-scale secondary flow, creating streamwise vortices that maintain coherence downstream over a distance of several channel widths.

  1. Implications of Historic River Channel Modifications on Contemporary Restoration Opportunities

    NASA Astrophysics Data System (ADS)

    Hanrahan, T. P.

    2013-12-01

    Identifying contemporary river management and restoration opportunities relies on understanding how river ecosystems respond to historic forcing from natural events and human impacts. Over the past 70 years, the Big Wood River in central Idaho, USA, has experienced significant engineered channel modifications and realignment, as well as natural changes in channel location and riverbank instability. Understanding the effects of these historic conditions on contemporary river characteristics and processes was needed to inform river management and restoration planning. A geomorphic assessment along 16 km of the Big Wood River was completed in order to understand the physical characteristics and processes upstream, within, and downstream of a 3 km long project reach. This evaluation included analysis of the longitudinal profile, planform pattern, cross-section dimensions, cross-section hydraulics, riverbed and riverbank materials, sediment transport conditions, and large roughness elements such as boulders and large wood material. As a result of residential and highway encroachment along the river corridor, river channel modifications (bank revetments, grade-control drop structures, training channels, sediment traps) have been implemented in attempts to limit the vertical and lateral channel adjustments that would negatively affect infrastructure along the river corridor. These river channel modifications have interrupted the geomorphic processes of the Big Wood River, and have initiated the need for ongoing maintenance of in-channel structures and new efforts at river restoration. Future river ecosystem response along this reach of the Big Wood River will be constrained as a result of river channel and floodplain modifications throughout the valley.

  2. Quaternary Morphodynamics for two large rivers: the Fly River, PNG, and the Mekong River, Cambodia.

    NASA Astrophysics Data System (ADS)

    Aalto, R. E.; Lauer, J. W.; Darby, S. E.; Goni, M. A.; Dietrich, W. E.

    2014-12-01

    During glacial marine transgressions, sediment & carbon are deposited due to the infilling of lowland fluvial systems, material that is then largely removed during ensuing regressions. Measuring & modelling these processes would help quantify the amount, timing, & preservation of these materials, providing insight into the morphodynamics of lowland fluvial systems in response to sea level change. We investigated the infilling dynamics of the Fly and Strickland Rivers, Papua New Guinea. Field data include: 14C dated deep cores recording base level evolution over the Holocene, sonar imaging of floodbasin stratigraphy, and the observations of blocked valley lakes and weathered erosional remnants from LGM conditions. Similar research was conducted on the Mekong River, Cambodia, where we have imaged basin fill stratigraphy and recorded the extent of blocked valley lakes. Such field data provide tantalizing empirical glimpses into the landscapes & flux buffering exhibited by large tropical rivers during glacial-interglacial transitions. We upscale our observations by modelling river system evolution, employing a GpU Lowland Landscape Evolution Model (GULLEM) to predict the evolution of the entire basin. A novel & powerful (>10 Tflops on an inexpensive computer) simulator, GULLEM models morphodynamics and estimates the accommodation space subsequently infilled during marine transgressions by representing a range of geomorphic processes, including: river & tributary incision, non-linear diffusion, sea level and isostatic change, hydraulic geometry, tectonic deformation, sediment production, transport & deposition, & tracking of the resulting stratigraphy. GULLEM's vectorized approach allows for massively parallel operation on GPUs (Graphics Processing Unit), making it practical to model coupled fluvial-landscape evolution for complex lowland river systems over large temporal and spatial scales. Our combined approach affords estimates for the timing and budgets of sediment

  3. Linking River Management-Induced Perturbations of Hydrologic and Sediment Regimes to Geomorphic Processes Along a Highly-Dynamic Gravel-Bed River: Snake River, WY.

    NASA Astrophysics Data System (ADS)

    Leonard, C.; Legleiter, C. J.

    2015-12-01

    Encroachment of human development onto river floodplains creates a need to stabilize rivers and provide flood protection. Structural interventions, such as levees, often perturb hydrologic and sediment regimes and thus can initiate morphological responses. An understanding of how human activities affect river morphodynamics and trigger channel change is needed to anticipate future river responses and facilitate effective restoration. This study examines approximately 66 km of the Snake River, WY, USA, and links sediment transport processes to channel form and behavior by developing a morphological sediment budget that spans both a natural, unconfined reach and a reach confined by artificial levees. Sediment transport rates are inferred from the morphological sediment budget and a bed mobility study is used to estimate entrainment thresholds that allow us to link the hydrological regime during the sediment budget period to the observed channel changes. Results indicate that lateral constriction by levees triggers a positive feedback mechanism by incising the bed, focusing flow energy, thus increasing transport capacity, and leading to armoring of the bed. In other systems, armoring promotes widening of the channel but in this case levees prevent widening and the channel instead migrates across the braidplain rapidly, producing further erosion of bars and vegetated islands that is expressed as negative net volumetric changes and increased sediment transport rates. Furthermore, decreased slopes and reduced discharges due to dam regulation in the upstream unconfined reach cause gravel sheets to stall on bars and in other areas of storage, creating a spatial discontinuity in sediment conveyance downstream, and thus contributing to the sediment deficit within the leveed reach.

  4. Optical water quality in rivers

    NASA Astrophysics Data System (ADS)

    Julian, J. P.; Doyle, M. W.; Powers, S. M.; Stanley, E. H.; Riggsbee, J. A.

    2008-10-01

    Optical water quality (OWQ) governs the quantity and quality of light in aquatic ecosystems, and thus spatiotemporal changes in OWQ affect many biotic and abiotic processes. Despite the fundamental role of light in rivers, studies on riverine OWQ have been limited and mostly descriptive. Here we provide a comprehensive, quantitative analysis of the controls and spatiotemporal dynamics of riverine OWQ, focusing on the inherent optical properties (IOPs), which are those that are only affected by water constituents and not by changes in the solar radiation field. First, we briefly review the constituents attenuating light in rivers. Second, we develop a new method for partitioning (light) beam attenuation into its constituent fractions. This method distinguishes between absorption and scattering by dissolved and particulate constituents, and further isolates particulates into mineral and organic components. Third, we compare base flow IOPs between four rivers with vastly different physical characteristics to illustrate intersite variability. Fourth, we analyze the spatial and temporal patterns of IOPs for the four rivers. Fifth, we quantify a longitudinal water clarity budget for one of the rivers. Finally, available data are synthesized to identify general spatial trends robust across broad geographic areas. Temporal trends in IOPs were largely dictated by storm frequency, while spatial trends were largely dictated by channel network configuration. Generally, water clarity decreased with increasing discharge primarily owing to greater scattering by particulates and secondarily to greater absorption by chromophoric dissolved organic matter. Water clarity also generally decreased longitudinally along the river owing to increased particulate inputs from tributaries; however, for pear-shaped, dendritic basins, water clarity reached a minimum at ˜70% of the channel length and then increased. By illustrating the controls and spatiotemporal variability of riverine OWQ

  5. Flooding on Elbe River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Heavy rains in Central Europe over the past few weeks have led to some of the worst flooding the region has witnessed in more than a century. The floods have killed more than 100 people in Germany, Russia, Austria, Hungary, and the Czech Republic and have led to as much as $20 billion in damage. This false-color image of the Elbe River and its tributaries was taken on August 20, 2002, by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite. The floodwaters that inundated Dresden, Germany, earlier this week have moved north. As can be seen, the river resembles a fairly large lake in the center of the image just south of the town of Wittenberg. Flooding was also bad further downriver in the towns of Maqgdeburge and Hitzacker. Roughly 20,000 people were evacuated from their homes in northern Germany. Fifty thousand troops, border police, and technical assistance workers were called in to combat the floods along with 100,000 volunteers. The floodwaters are not expected to badly affect Hamburg, which sits on the mouth of the river on the North Sea. Credit:Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  6. A study of the management strategies for river aeolian dust inhibition at the estuary of Zhuo-shui River

    NASA Astrophysics Data System (ADS)

    Tsai, S. F.; Lin, C. Y.

    2014-12-01

    With the characteristics of humidity in summer and drought in winter, there existing lots of bare lands due to the decline of water level cause large amounts of aeolian dust and environmental deterioration during the monsoon seasons in central Taiwan. How to adopt effective measures to inhibit the damage of dust is an essential issue. This study selected the serious dust-affected section of Zhuo-shui river (bridge Zi-qiang to Xi-bin) to delineate the areas of potential aeolian dust occurrence, explore the relationship between elevation and water level determined from return period analysis, submit the countermeasures for dust inhibition at the bare lands and/or cultivated areas, and address the responsibilities of related authority offices for dust prevention by means of literature review. The return period of inundation for the areas of potential aeolian dust occurrence is 1.1 years. Engineering of dust prevention with highly unit price are not recommended due to could be destroyed annually. The deposition sites of a river are usually located at the convex bank, which with silt texture and high salinity are not suitable for cultivation, are delineated as the areas of potential aeolian dust occurrence. Besides technology consideration in dust prevention, this study also examined the related articles of river management to integrate a comprehensive vision for better riverside environment and air quality.

  7. Monitor well responses at the Raft River, Idaho, Geothermal Site

    SciTech Connect

    Skiba, P.A.; Allman, D.W.

    1984-05-01

    Effects of geothermal fluid production and injection on overlying ground-water aquifers have been studied at the Raft River Geothermal Site in southcentral Idaho. Data collected from 13 monitor wells indicate a complex fractured and porous media controlled ground-water flow system affected by natural recharge and discharge, irrigation withdrawal, and geothermal withdrawal and injection. The monitor wells are completed in aquifers and aquitards overlying the principal geothermal aquifers. Potentiometric heads and water quality are significantly affected by natural upward geothermal leakage via faults and matrix seepage. No significant change in water quality data has been observed, but potentiometric head changes resulted due to geothermal resource testing and utilization. Long-term hydrographs for the wells exhibit three distinct patterns, with superimposed responses due to geothermal pumping and injection. Well hydrographs typical of the Shallow aquifer exhibit effects of natural recharge and irrigation withdrawals. For selected wells, pressure declines due to injection and pressure buildup associated with pumping are observed. The latter effect is presumably due to the elastic deformation of geologic material overlying the stressed aquifers. A second distinct pattern occurs in two wells believed to be hydraulically connected to the underlying Intermediate aquifer via faults. These wells exhibit marked buildup effects due to injection as well as responses typical of the Shallow aquifer. The third pattern is demonstrated by three monitor wells near the principal production wells. This group of wells exhibits no seasonal potentiometric head fluctuations. Fluctuations which do occur are due to injection and pumpage. The three distinct hydrograph patterns are composites of the potentiometric head responses occurring in the various aquifers underlying the Raft River Site.

  8. Basin-scale characterization of river hydromorphology by map derived information: A case study on the Red River (Sông Hông), Vietnam

    NASA Astrophysics Data System (ADS)

    Schmitt, R. J.; Bizzi, S.; Castelletti, A.

    2012-12-01

    The understanding of river hydromorphological processes has been recognized in the last decades as a priority of modern catchment management, since fluvial geomorphic processes shape physical habitat, affect river infrastructures and influence freshwater ecological processes. Characterization of river hydromorphological features is commonly location specific and highly demanding in terms of field-works, resource and expertise required. Therefore, its routine application at regional or national scales, although an urgent need of catchment management, is infeasible at present. Recently available high-resolution data, such as DEM or LIDAR, opens up novel potential for basin-wide analysis of fluvial processes at limited effort and cost. Specifically, in this study we assess the feasibility of characterizing river hydromorphology from specific map derived geomorphic controls namely: channel gradient, bankfull flow, specific stream power, and degree of channel confinement. The river network, extracted from a digital elevation model and validated with available network shape-files and optical satellite imagery, available flow gauging stations and GIS processing allow producing continuous values of geomorphic drivers defined over given length segments at catchment or regional scales. This generic framework was applied to the Red River (Sông Hông) basin, the second largest basin (87,800 km2) in Vietnam. Besides its economic importance, the river since few years is experiencing severe river bed incisions due to the building of new dams in the upstream part of the catchment and sand mining in the surrounding of the capital city Hanoi. In this context, characterized by an high developing rate, current efforts to increase water productivity by infrastructure and management measures require a thorough understanding of fluvial system and, in particular, of the basin-wide river hydromorphology. The framework proposed has allowed producing high-dimensional samples of spatially

  9. Affective Learning.

    ERIC Educational Resources Information Center

    Brown, Charles T.

    This paper addresses itself to the question, "What does feeling have to do with knowing?" Two movements in affective education are discussed which have come into focus in recent years and which attempt to define the relationship between knowing and feeling. The first, a conscious application of the role of arousal in learning, emphasizes arousal…

  10. Rapid, Human-Induced Siltation of the Macro-Tidal Ord River Estuary, Western Australia

    NASA Astrophysics Data System (ADS)

    Wolanski, E.; Moore, K.; Spagnol, S.; D'Adamo, N.; Pattiaratchi, C.

    2001-11-01

    Field studies on the sediment dynamics of the two arms of Cambridge Gulf, tropical Western Australia, were undertaken. The system is macro-tidal with 8 m tides. The West Arm is the estuary of the Durack and Pentecost rivers, which are largely untouched by human activities. The East Arm is the estuary of the Ord River affected by land clearing which started 100 years ago, and by two river dams constructed 30 years ago. Prior to damming of the Ord River, the natural flow in all rivers was highly seasonal, characterized by small, at times negligible, flow during the dry season, which lasts eight months, and occasional river floods during the wet season, which lasts four months. The river flow has been regulated in the East Arm as a result of damming; this resulted in suppressing large river floods. The salinity intrusion length has decreased by about 50% in the East Arm following river damming. The East Arm has silted measurably over the last 30 years, with the stream cross-sectional area decreasing by about 50%. Field and numerical studies suggest that this is due to the dam-induced suppression of large river floods, which has in turn allowed a greater amount of tidal pumping of sediment into the East Arm from Cambridge Gulf. Since tidal pumping is increasing as the system is silting, the East Arm appears to now be geomorphologically unstable as a result of human activities. Numerical studies suggest it may take as little as 100 years for the Ord River to reach a new equilibrium. Modelling suggests that this equilibrium may be characterized by a salinity intrusion length half that before damming, a channel width and depth reduced by 70%, and a much stronger tidal asymmetry characterized by an increasing size of the tidal bore. The West Arm appears to be at equilibrium since there has been no net loss or gain of sediment for the last 111 years. Tidal dynamics and river floods appear responsible for self-scouring this channel.

  11. Variability of Ecosystem State in Rivers Containing Natural Dams: A Chemical Analysis

    NASA Astrophysics Data System (ADS)

    Reynolds, Z. A.

    2015-12-01

    Flooding, and the resulting economic damage to roads and property, is associated with natural dams such as beaver dams or log jams. For this reason, humans often remove natural dams; however, river reaches with natural dams provide very different ecosystem services in comparison with free-flowing river reaches. Therefore, the goal of this project is to assess the differences in ecosystem state between these different river reach types in the northeastern United States. We focused on differences in basic chemistry (e.g., dissolved oxygen, pH, temperature, and organic carbon) to assess the impact of natural dams on river ecosystem state. Study sites include rivers in the White Mountains and southeastern New Hampshire at locations with beaver dams, beaver ponds, beaver meadows, log jams, and free-flowing reaches. Dissolved oxygen, ORP, pH, temperature, and conductivity were measured in the field with a YSI Professional Plus meter. Water samples were collected for subsequent laboratory analysis of total organic carbon with a Shimadzu TOC-L. Preliminary results show that the chemistry of river water varies with feature type. Most significantly, dissolved oxygen concentrations are highest in free-flowing reaches and lowest in beaver ponds. Although beaver ponds are often associated with lower pH, due the increased concentration of organic acids, some beaver ponds can increase pH when compared to free-flowing reaches on the same river. Early results also show that water chemistry returns quickly to the chemistry typical of the free-flowing river reaches after being altered by a natural dam. Overall, natural dams create a river system that has more heterogeneity, and therefore has opportunities to provide more ecosystem functions, than a purely free-flowing river; this can increase the number of supported instream and riparian species. By increasing the understanding of how natural dams affect the chemistry of river water, river engineers can improve their decisions on how

  12. Additional challenges for uncertainty analysis in river engineering

    NASA Astrophysics Data System (ADS)

    Berends, Koen; Warmink, Jord; Hulscher, Suzanne

    2016-04-01

    The management of rivers for improving safety, shipping and environment requires conscious effort on the part of river managers. River engineers design hydraulic works to tackle various challenges, from increasing flow conveyance to ensuring minimal water depths for environmental flow and inland shipping. Last year saw the completion of such large scale river engineering in the 'Room for the River' programme for the Dutch Rhine River system, in which several dozen of human interventions were built to increase flood safety. Engineering works in rivers are not completed in isolation from society. Rather, their benefits - increased safety, landscaping beauty - and their disadvantages - expropriation, hindrance - directly affect inhabitants. Therefore river managers are required to carefully defend their plans. The effect of engineering works on river dynamics is being evaluated using hydraulic river models. Two-dimensional numerical models based on the shallow water equations provide the predictions necessary to make decisions on designs and future plans. However, like all environmental models, these predictions are subject to uncertainty. In recent years progress has been made in the identification of the main sources of uncertainty for hydraulic river models. Two of the most important sources are boundary conditions and hydraulic roughness (Warmink et al. 2013). The result of these sources of uncertainty is that the identification of single, deterministic prediction model is a non-trivial task. This is this is a well-understood problem in other fields as well - most notably hydrology - and known as equifinality. However, the particular case of human intervention modelling with hydraulic river models compounds the equifinality case. The model that provides the reference baseline situation is usually identified through calibration and afterwards modified for the engineering intervention. This results in two distinct models, the evaluation of which yields the effect of

  13. Topsoil structure as an indicator of river restoration success

    NASA Astrophysics Data System (ADS)

    Bullinger-Weber, Géraldine; Le Bayon, Renée.-Claire; Verrecchia, Eric; Guenat, Claire

    2010-05-01

    Braided rivers were in the past one of the most typical landscapes of Swiss alpine and pre-alpine valleys. However since the middle of the 19th century, this landscape has progressively disappeared, largely due to the development of flood protection structures and water exploitation for reasons of energy and food security. In the last 20 years, the number of river restoration projects aiming to re-establish the structure and ecological functions of floodplains has increased. Nowadays, there is a lack of methodology to evaluate the success of these projects. As alluvial soils exhibit characteristics of both sediment transport and deposition, and in situ pedogenesis, we propose to use soil as an indicator of success of river restoration. Indeed, the soil morphology reflects the efficiency of the fluvial dynamic and consequently affects the diversity and characteristics of terrestrial habitats. The effects of river widening on changes of soil morphology and especially on the humus structure are studied, by comparing a restored river area and an embanked area. The study site, named Schäuffäuli, is located along the Thur River (TG/ZH, Switzerland) and has mainly been restored in 2002. Different methods are used: soil profile descriptions, humus characterisation based on porosity measurements (porosimeter and polished slabs), structural stability (calculation of MWD), amount of organic carbon, and total nitrogen in the different sizes of soil aggregates. A complete linkage clustering applied to the soil profile dataset (110 soil profile descriptions based on field morphological characteristics) allows the identification of 8 different morphological groups. We demonstrate that river widening deeply modifies the soil morphology, especially close to the river. The frequency of thick soils as well as soils with hydromorphic features decreases while bare soils appear close to the riverbed. Some soils, under mature forest, are not modified by the river widening. Along a

  14. Balancing hydropower production and river bed incision in operating a run-of-river hydropower scheme along the River Po

    NASA Astrophysics Data System (ADS)

    Denaro, Simona; Dinh, Quang; Bizzi, Simone; Bernardi, Dario; Pavan, Sara; Castelletti, Andrea; Schippa, Leonardo; Soncini-Sessa, Rodolfo

    2013-04-01

    Water management through dams and reservoirs is worldwide necessary to support key human-related activities ranging from hydropower production to water allocation, and flood risk mitigation. Reservoir operations are commonly planned in order to maximize these objectives. However reservoirs strongly influence river geomorphic processes causing sediment deficit downstream, altering the flow regime, leading, often, to process of river bed incision: for instance the variations of river cross sections over few years can notably affect hydropower production, flood mitigation, water supply strategies and eco-hydrological processes of the freshwater ecosystem. The river Po (a major Italian river) has experienced severe bed incision in the last decades. For this reason infrastructure stability has been negatively affected, and capacity to derive water decreased, navigation, fishing and tourism are suffering economic damages, not to mention the impact on the environment. Our case study analyzes the management of Isola Serafini hydropower plant located on the main Po river course. The plant has a major impact to the geomorphic river processes downstream, affecting sediment supply, connectivity (stopping sediment upstream the dam) and transport capacity (altering the flow regime). Current operation policy aims at maximizing hydropower production neglecting the effects in term of geomorphic processes. A new improved policy should also consider controlling downstream river bed incision. The aim of this research is to find suitable modeling framework to identify an operating policy for Isola Serafini reservoir able to provide an optimal trade-off between these two conflicting objectives: hydropower production and river bed incision downstream. A multi-objective simulation-based optimization framework is adopted. The operating policy is parameterized as a piecewise linear function and the parameters optimized using an interactive response surface approach. Global and local

  15. Streamflow and nutrient data for the Yazoo River below Steele Bayou near Long Lake, Mississippi, 1996-2000

    USGS Publications Warehouse

    Runner, Michael S.; Turnipseed, D. Phil; Coupe, Richard H.

    2002-01-01

    Increased nutrient loading to the Gulf of Mexico from off-continent flux has been identified as contributing to the increase in the areal extent of the low dissolved-oxygen zone that develops annually off the Louisiana and Texas coast. The proximity of the Yazoo River Basin in northwestern Mississippi to the Gulf of Mexico, and the intensive agricultural activities in the basin have led to speculation that the Yazoo River Basin contributes a disproportionate amount of nitrogen and phosphorus to the Mississippi River and ultimately to the Gulf of Mexico. An empirical measurement of the flux of nitrogen and phosphorus from the Yazoo Basin has not been possible due to the hydrology of the lower Yazoo River Basin. Streamflow for the Yazoo River below Steele Bayou is affected by backwater from the Mississippi River. Flow at the gage is non-uniform and varying, with bi-directional and reverse flows possible. Streamflow was computed by using remote sensing and acoustic and conventional discharge and velocity measurement techniques. Streamflow from the Yazoo River for the 1996-2000 period accounted for 2.8 percent of the flow of the Mississippi River for the same period. Water samples from the Yazoo River were collected from February 1996 through December 2000 and were analyzed for total nitrogen, nitrate, total phosphorus, and orthophosphorus as part of the U.S. Geological Survey National Water-Quality Assessment Program. These data were used to compute annual loads of nitrogen and phosphorus discharged from the Yazoo River for the period 1996-2000. Annual loads of nitrogen and phosphorus were calculated by two methods. The first method used multivariate regression and the second method multiplied the mean annual concentration by the total annual flow. Load estimates based on the product of the mean annual concentration and the total annual flow were within the 95 percent confidence interval for the load calculated by multivariate regression in 10 of 20 cases. The Yazoo

  16. [Dermatomycoses due to dermatophytes].

    PubMed

    Piérard, G E

    2016-03-01

    Dermatophytoses are frequent skin diseases. They are caused by anthropophilic, zoophilic or geophilic agents from the Trichophyton, Microsporum and Epidermophyton genus. The clinical aspects distinguish diverse tinea on the scalp, distinct tinea of glabrous skin corresponding to lesions on the body, face, large folds as well as on palms and soles. Nails are also affected by dermatophytes. According to the involved area, the antifungal treatments are adapted to the nature and location of the fungus. PMID:27311247

  17. Evaluating Water Quality in the Lovros River (Greece), Using Biotic Indices based on Invertebrate Communities.

    ERIC Educational Resources Information Center

    Koussouris, Theodore; And Others

    1990-01-01

    Presented is a survey of a river including physiochemical measurements and river fauna observations. It is shown that the self-purification gradient of river water quality and the possible ecological disturbances due to pollutants entering the river create an unpredictable pattern of recovery. (CW)

  18. Columbia River Impact Evaluation Plan

    SciTech Connect

    Weiss, S.G.

    1994-03-01

    A preliminary impact evaluation was conducted to assess the adequacy of existing data and proposed data collection programs for evaluating cumulative health and environmental impacts to the Columbia River due to past practices at the Hanford Site. The results of this evaluation were used to develop this plan to ensure collection of sufficient data for adequate characterization of the Columbia River along the 100 Area for CERCLA purposes. The evaluation used to develop the plan is not a risk assessment; the plan presented here is only a mechanism to collect additional data to support a future risk assessment.

  19. Canoeing the Murray River (Australia) as Environmental Education: A Tale of Two Rivers

    ERIC Educational Resources Information Center

    Stewart, Alistair

    2004-01-01

    The Murray River, lying at the heart of Australia's largest catchment, is used extensively in outdoor education programs in south-eastern Australia. Since European settlement the river's ecological health has declined considerably due to activities such as damming for irrigation and clearing of native vegetation. Colonial notions of how the river…

  20. Malheur River Wildlife Mitigation Project, Annual Report 2003.

    SciTech Connect

    Ashley, Paul

    2004-01-01

    Hydropower development within the Columbia and Snake River Basins has significantly affected riparian, riverine, and adjacent upland habitats and the fish and wildlife species dependent upon them. Hydroelectric dams played a major role in the extinction or major loss of both anadromous and resident salmonid populations and altered instream and adjacent upland habitats, water quality, and riparian/riverine function. Hydroelectric facility construction and inundation directly affected fish and wildlife species and habitats. Secondary and tertiary impacts including road construction, urban development, irrigation, and conversion of native habitats to agriculture, due in part to the availability of irrigation water, continue to affect wildlife and fish populations throughout the Columbia and Snake River Basins. Fluctuating water levels resulting from facility operations have created exposed sand, cobble, and/or rock zones. These zones are generally devoid of vegetation with little opportunity to re-establish riparian plant communities. To address the habitat and wildlife losses, the United States Congress in 1980 passed the Pacific Northwest Electric Power Planning and Conservation Act (Act) (P.L. 96-501), which authorized the states of Idaho, Montana, Oregon, and Washington to create the Northwest Power Planning Council (Council). The Act directed the Council to prepare a program in conjunction with federal, state, and tribal wildlife resource authorities to protect, mitigate, and enhance fish and wildlife species affected by the construction, inundation and operation of hydroelectric dams in the Columbia River Basin (NPPC 2000). Under the Columbia Basin Fish and Wildlife Program (Program), the region's fish and wildlife agencies, tribes, non-government organizations (NGOs), and the public propose fish and wildlife projects that address wildlife and fish losses resulting from dam construction and subsequent inundation. As directed by the Council, project proposals are

  1. Human due diligence.

    PubMed

    Harding, David; Rouse, Ted

    2007-04-01

    Most companies do a thorough job of financial due diligence when they acquire other companies. But all too often, deal makers simply ignore or underestimate the significance of people issues in mergers and acquisitions. The consequences are severe. Most obviously, there's a high degree of talent loss after a deal's announcement. To make matters worse, differences in decision-making styles lead to infighting; integration stalls; and productivity declines. The good news is that human due diligence can help companies avoid these problems. Done early enough, it helps acquirers decide whether to embrace or kill a deal and determine the price they are willing to pay. It also lays the groundwork for smooth integration. When acquirers have done their homework, they can uncover capability gaps, points of friction, and differences in decision making. Even more important, they can make the critical "people" decisions-who stays, who goes, who runs the combined business, what to do with the rank and file-at the time the deal is announced or shortly thereafter. Making such decisions within the first 30 days is critical to the success of a deal. Hostile situations clearly make things more difficult, but companies can and must still do a certain amount of human due diligence to reduce the inevitable fallout from the acquisition process and smooth the integration. This article details the steps involved in conducting human due diligence. The approach is structured around answering five basic questions: Who is the cultural acquirer? What kind of organization do you want? Will the two cultures mesh? Who are the people you most want to retain? And how will rank-and-file employees react to the deal? Unless an acquiring company has answered these questions to its satisfaction, the acquisition it is making will be very likely to end badly.

  2. The influence of extreme river discharge conditions on the quality of suspended particulate matter in Rivers Meuse and Rhine (The Netherlands).

    PubMed

    Hamers, Timo; Kamstra, Jorke H; van Gils, Jos; Kotte, Marcel C; van Hattum, Albertus G M

    2015-11-01

    compete with thyroid hormone to bind to TTR, possibly due to the presence of fycotoxins. Meanwhile concentrations of polychlorobiphenyls (PCBs) in SPM were also increased. Very high River Meuse discharges on the other hand corresponded to increased androgenic and AhR agoniztic responses, which coincided with increased PAH levels and PAH-related in vivo risk estimates (i.e. multi-substance potentially affected fraction of species; msPAF). In River Rhine, very high discharges also corresponded to increasing androgenic potencies in SPM. Concentrations and corresponding msPAF values of PAHs (and metals), however, decreased with very high discharges in River Rhine in contrast to River Meuse. Mutagenicity was observed for SPM extracts from River Rhine collected during all discharge conditions, except during regular discharge. Aggregated toxicity index values, which were useful to identify toxicity profiles deviating from the generally observed pattern, did not correlate with river discharges, probably due to opposite effects of discharge conditions on different bioassay responses. In conclusion, SPM quality and related in vivo risk estimates changed during very low or very high discharge conditions but the changes were specific for the different toxic endpoints and pollutants in the different rivers. Moreover, bioassay responses to a series of consecutively collected samples from River Rhine during the Christmas flood of 1993 indicated that SPM quality is variable within a single episode of extreme discharge.

  3. Sediment budget analysis from Landslide debris and river channel change during the extreme event - example of Typhoon Morakot at Laonong river, Taiwan

    NASA Astrophysics Data System (ADS)

    Chang, Kuo-Jen; Huang, Yu-Ting; Huang, Mei-Jen; Chiang, Yi-Lin; Yeh, En-Chao; Chao, Yu-Jui

    2014-05-01

    Taiwan, due to the high seismicity and high annual rainfall, numerous landslides triggered every year and severe impacts affect the island. Typhoon Morakot brought extreme and long-time rainfall for Taiwan in August 2009. It further caused huge loss of life and property in central and southern Taiwan. Laonong River is the largest tributary of Gaoping River. It's length is 137 km, and the basin area is 1373 km2. More than 2000mm rainfall brought and maximum rainfall exceeded 100mm/hr in the region by Typhoon Morakot in Aug, 2009. Its heavy rains made many landslides and debris flew into the river and further brought out accumulation and erosion on river banks of different areas. It caused severe disasters within the Laonong River drainage. In the past, the study of sediment blockage of river channel usually relies on field investigation, but due to inconvenient transportation, topographical barriers, or located in remote areas, etc. the survey is hardly to be completed sometimes. In recent years, the rapid development of remote sensing technology improves image resolution and quality significantly. Remote sensing technology can provide a wide range of image data, and provide essential and precious information. Furthermore, although the amount of sediment transportation can be estimated by using data such as rainfall, river flux, and suspended loads, the situation of large debris migration cannot be studied via those data. However, landslides, debris flow and river sediment transportation model in catchment area can be evaluated easily through analyzing the digital terrain model (DTM) . The purpose of this study is to investigate the phenomenon of river migration and to evaluate the amount of migration along Laonong River by analyzing the DEM before and after the typhoon Morakot. The DEMs are built by using the aerial images taken by digital mapping camera (DMC) and by airborne digital scanner 40 (ADS 40) before and after typhoon event. The results show that lateral

  4. Perfluoroalkyl substances in the Ebro and Guadalquivir river basins (Spain).

    PubMed

    Lorenzo, María; Campo, Julián; Farré, Marinella; Pérez, Francisca; Picó, Yolanda; Barceló, Damià

    2016-01-01

    Mediterranean rivers are characteristically irregular with changes in flow and located in high population density areas. This affects the concentration of pollutants in the aquatic environments. In this study, the occurrence and sources of 21 perfluoroalkyl substances (PFASs) were determined in water, sediment and biota of the Ebro and Guadalquivir river basins (Spain). In water samples, of 21 analytes screened, 11 were found in Ebro and 9 in Guadalquivir. In both basins, the most frequents were PFBA, PFPeA and PFOA. Maximum concentration was detected for PFBA, up to 251.3 ng L(-1) in Ebro and 742.9 ng L(-1) in Guadalquivir. Regarding the sediments, 8 PFASs were detected in the samples from Ebro and 9 in those from Guadalquivir. The PFASs most frequently detected were PFBA, PFPeA, PFOA and PFOS. Maximum concentration in Ebro samples was, in dry weight, for PFOA (32.3 ng g(-1)) and in Guadalquivir samples for PFBA (63.8 ng g(-1)). For biota, 12 PFASs were detected in fish from the Ebro River and only one (PFOS) in that from Guadalquivir. In the Ebro basin, the most frequents were PFBA, PFHxA, PFOA, PFBS, PFOS and PFOSA. Maximum concentration in Ebro samples was, in wet weight, for PFHxA with 1280.2 ng g(-1), and in Guadalquivir samples for PFOS with 79.8 ng g(-1). These compounds were detected in the whole course of the rivers including the upper parts. In some points contamination was due to point sources mostly related to human activities (e.g. ski resorts, military camps, urban areas.). However, there are also some areas clearly affected by diffuse sources as atmospheric deposition. PMID:26250865

  5. Degradation of Terrace Risers: Analysis of Hillslope Diffusion due to Physical, Biological and Climatic Processes

    NASA Astrophysics Data System (ADS)

    Clarke, B. A.; Burbank, D. A.

    2005-12-01

    River-cut terrace risers form at a known initial geometry. Their subsequent degradation, from down-slope transport of sediment, is an aggregate of hillslope processes, mainly attributed to particle-by-particle gravitational unraveling and biological disturbances. This study examines the ability of linear, non-linear, and geometric models to quantify terrace degradation through time and accurately depict the resulting geomorphic form. In addition to the physical processes, the effects of microclimate, due to slope aspect and inclination, strongly affect local degradation rates. By comparing terraces risers from the Ohau River in the McKenzie Basin, New Zealand, where there are no native burrowing mammals, to terraces from Grand Teton National Park, North America, we can compare factors affecting hillslope diffusion and perhaps isolate localized effects on degradation rates and terrace profile form due to burrowing mammals and microclimate. Preliminary analysis of terrace profiles in both regions reveals asymmetric slope and curvature profiles between the upper and lower portion of the terrace risers, as well as correlations between diffusion rates and terrace height. Analysis of profile slope and curvature suggests a non-linear relation between sediment flux and gradient, and imply a heterogeneous diffusion coefficient over the length of individual profiles, caused by varying intensities of dominant transport processes. Initial results suggest that increases in sediment transport rates due to burrowing mammals are minimal. Increases in sediment flux due to burrowing mammals are masked by more dominant gravitational unraveling processes and the effect of terrace height and microclimate. Additionally, the diffusion coefficient, which controls the efficiency of degradation, may vary over the length of the profile, thus creating distinct asymmetries in slope and curvature. Through the analysis of terraces of known age, the results of this study are used to back

  6. Osmium in the rivers

    NASA Astrophysics Data System (ADS)

    Sharma, M.; Wasserburg, G. J.

    1997-12-01

    There is a large uncertainty in our understanding of the behavior of osmium during weathering and transport into deep oceans and the osmium budget of the oceans. The problem stems chiefly from the lack of osmium data on the dissolved load in the rivers and in the estuaries. In this study, the concentration and isotopic composition of osmium have been determined in three North American rivers (the Mississippi, the Columbia, and the Connecticut) and one river draining central Europe and flowing into the Baltic Sea (the Vistula). Osmium concentration in the Mississippi and the Vistula is about 45 femto mol kg -1; it is about 14 and 15 femto mol kg -1 for the Connecticut and the Columbia, respectively. The 187Os/186Os ratios estimated for the Mississippi and the Vistula are 10.4 and 10.7, respectively. For the Connecticut and the Columbia 187Os/186Os = 8.8 and 14.4 , respectively. Of all the rivers examined, the Mississippi is by far the largest, supplying ˜1.6% of the total annual world river flow. Its osmium isotopic composition is identical to the upper Mississippi valley loesses (Esser and Turekian, 1993a) indicating (1) congruent dissolution of the bedrock and (2) little or no impact of anthropogenic sources on the osmium isotopic composition of the dissolved load. The latter obserbation indicates that the upper limit of the anthropogenic input in the dissolved osmium load of the Mississippi outflow is about 250 g yr -1. While the osmium concentration of the Vistula is high the isotopic composition does not appear to have been affected by substantial pollution. The river data can be used to put limits on the mean residence time of osmium in the oceans ( overlineτOs) and on the osmium budget of the oceans. If the bulk river influx of dissolved osmium into the oceans is similar to that of the Mississippi, we get a value for the net riverine inflow of osmium of 1680 mol yr -1. If there were no sequestering of osmium in the estuaries, this would give a value of

  7. Mouth of the Ob River, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite shows the cause and effect of the large-scale seasonal flooding experienced on rivers throughout Siberia each year. Because many Siberian rivers flow from south to north, they flood regularly in the spring as meltwater from southern latitudes backs up against the still-frozen northern reaches of the rivers.These images show the Ob' River on the western edge of the Central Siberian Plateau. The images from June 20, 2002, show the mouth of the Ob' River (large river at left) where it empties into Kara Sea. In the false-color image, Vegetation appears in bright green, water appears dark blue or black, and ice appears bright blue. The ice is still choking the river's outlet to the sea.The effect of this ice block on the more southern stretches of the river can be seen in the images captured on June 17. In the false-color image, water is black, vegetation is in shades of gold and green, and clouds are pale orange. In the northernmost portion of the Ob' visible in this image (the Ob' runs southeast to northwest in the image), what is normally a fine mesh of braided streams and branches of the river channel has become almost a lake in places. The flood waters have engorged the river to 52 kilometers (32 miles) wide in places. Rivers can back up for hundreds of miles, and cause devastating flooding for towns and villages along the banks. Often, explosives are dropped into ice jams in an effort to free the river and give the flood waters a chance to escape. The spring and summer floods of 2002 have proven to be quite severe and perhaps as many as 100,000 people have been affected across the country. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  8. Explore the impacts of river flow and quality on biodiversity for water resources management by AI techniques

    NASA Astrophysics Data System (ADS)

    Chang, Fi-John; Tsai Tsai, Wen-Ping; Chang, Li-Chiu

    2016-04-01

    Water resources development is very challenging in Taiwan due to her diverse geographic environment and climatic conditions. To pursue sustainable water resources development, rationality and integrity is essential for water resources planning. River water quality and flow regimes are closely related to each other and affect river ecosystems simultaneously. This study aims to explore the complex impacts of water quality and flow regimes on fish community in order to comprehend the situations of the eco-hydrological system in the Danshui River of northern Taiwan. To make an effective and comprehensive strategy for sustainable water resources management, this study first models fish diversity through implementing a hybrid artificial neural network (ANN) based on long-term observational heterogeneity data of water quality, stream flow and fish species in the river. Then we use stream flow to estimate the loss of dissolved oxygen based on back-propagation neural networks (BPNNs). Finally, the non-dominated sorting genetic algorithm II (NSGA-II) is established for river flow management over the Shihmen Reservoir which is the main reservoir in this study area. In addition to satisfying the water demands of human beings and ecosystems, we also consider water quality for river flow management. The ecosystem requirement takes the form of maximizing fish diversity, which can be estimated by the hybrid ANN. The human requirement is to provide a higher satisfaction degree of water supply while the water quality requirement is to reduce the loss of dissolved oxygen in the river among flow stations. The results demonstrate that the proposed methodology can offer diversified alternative strategies for reservoir operation and improve reservoir operation strategies for producing downstream flows that could better meet both human and ecosystem needs as well as maintain river water quality. Keywords: Artificial intelligence (AI), Artificial neural networks (ANNs), Non

  9. Ganges River Delta

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Ganges River forms an extensive delta where it empties into the Bay of Bengal. The delta is largely covered with a swamp forest known as the Sunderbans, which is home to the Royal Bengal Tiger. It is also home to most of Bangladesh, one of the world's most densely populated countries. Roughly 120 million people live on the Ganges Delta under threat of repeated catastrophic floods due to heavy runoff of meltwater from the Himalayas, and due to the intense rainfall during the monsoon season. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on February 28, 2000. This is a false-color composite image made using green, infrared, and blue wavelengths. Image provided by the USGS EROS Data Center Satellite Systems Branch

  10. Valleywide patterns of posteruption erosion and deposition in the South Fork Toutle River, Washington—evidence of valley morphology and hillslope-channel coupling affecting sediment supply, storage, and delivery

    NASA Astrophysics Data System (ADS)

    Major, J. J.; Mark, L.

    2009-12-01

    Following the May 1980 eruption of Mount St. Helens, greatly elevated sediment loads issued from river valleys heavily impacted by the eruption. The extraordinary sediment loads resulted chiefly from erosion of thick deposits of fresh volcanic sediment. Within 5 years of the eruption, loads from some basins returned to pre-eruption levels, whereas in others they remain elevated after nearly 3 decades. In the South Fork Toutle (SFT) River basin on the volcano’s west flank, sediment loads remain highly variable and commonly are equivalent to or exceed those measured in the early 1980s. To gain insights on the sources of the sediment loads, their longevity, and the causes of their anomalously high variability compared to neighboring basins, we examined vertical topographic changes among a time-series of digital elevation models (DEMs; RMSE ˜3m) made from aerial photographs and lidar of the 50-km-long valley. The DEMs represent posteruption conditions in June 1980, 2000, and 2003. Our examination reveals patterns of erosion and deposition that appear to be controlled by valley morphology and hillslope-channel coupling. Between 1980 and 2000, erosion and deposition were focused in alternating reach-scale hotspots (˜3 km long). Within 15 km of the summit, long-term net channel deposition predominated, but sandwiched a 3-km-long reach of intense erosion. Net deposition proximal to the volcano was likely the result of persistent sediment influx from the high, steep flanks of the volcano, composed of unconsolidated, readily erodible sediment prone to mass wasting. Reach-scale deposition downstream of reach-scale erosion occurred in reaches of valley expansion, in valley embayments, and where channels abutted steep hillslopes. In the valley’s distal 10 km, where the channel is less directly connected to hillslopes, where hillslope sediment sources capable of channel replenishment are more limited, and where sediment removal outpaced upstream sediment input, long

  11. Effects of Reduced Summer Precipitation on Productivity and Forage Quality of Floodplain Meadows at the Elbe and the Rhine River

    PubMed Central

    Ludewig, Kristin; Donath, Tobias W.; Zelle, Bianka; Eckstein, R. Lutz; Mosner, Eva; Otte, Annette; Jensen, Kai

    2015-01-01

    Background Floodplain meadows along rivers are semi-natural habitats and depend on regular land use. When used non-intensively, they offer suitable habitats for many plant species including rare ones. Floodplains are hydrologically dynamic ecosystems with both periods of flooding and of dry conditions. In German floodplains, dry periods may increase due to reduced summer precipitation as projected by climate change scenarios. Against this background, the question arises, how the forage quantity and quality of these meadows might change in future. Methods We report results of two field trials that investigated effects of experimentally reduced summer precipitation on hay quantity and quality of floodplain meadows at the Rhine River (2011-2012) and at two Elbe tributaries (2009-2011). We measured annual yield, the amount of hay biomass, and contents of crude protein, crude fibre, energy, fructan, nitrogen, phosphorus, and potassium. Results The annual yield decreased under precipitation reduction at the Rhine River. This was due to reduced productivity in the second cut hay at the Rhine River in which, interestingly, the contents of nitrogen and crude protein increased. The first cut at the Rhine River was unaffected by the treatments. At the Elbe tributaries, the annual yield and the hay quantity and quality of both cuts were only marginally affected by the treatments. Conclusion We conclude that the yield of floodplain meadows may become less reliable in future since the annual yield decreased under precipitation reduction at the Rhine River. However, the first and agriculturally more important cut was almost unaffected by the precipitation reduction, which is probably due to sufficient soil moisture from winter/spring. As long as future water levels of the rivers will not decrease during spring, at least the use of the hay from the first cut of floodplain meadows appears reliable under climate change. PMID:25950730

  12. Conceptualizing and Communicating River Restoration

    NASA Astrophysics Data System (ADS)

    Jacobosn, R. B.

    2007-12-01

    River restoration increasingly involves collaboration with stakeholders having diverse values and varying technical understanding. In cases where river restoration proceeds through collaborative processes, scientists are required to communicate complex understanding about riverine ecosystem processes to broad audiences. Of particular importance is communication of uncertainties in predictions of ecosystem responses to restoration actions, and how those uncertainties affect monitoring and evaluation strategies. I present a relatively simple conceptual model of how riverine ecosystems operate. The model, which has been used to conceptualize and communicate various river-restoration and management processes in the Lower Missouri River, emphasizes a) the interdependencies of driving regimes (for example, flow, sediment, and water quality), b) the filtering effect of management history, c) the typical hierarchical nature of information about how ecosystems operate, and d) how scientific understanding interacts with decision making. I provide an example of how the conceptual model has been used to illustrate the effects of extensive channel re-engineering of the Lower Missouri River which is intended to mitigate the effects of channelization and flow regulation on aquatic and flood-plain ecosystems. The conceptual model illustrates the logic for prioritizing investments in monitoring and evaluation, interactions among ecosystem components, tradeoffs between ecological and social-commercial benefits, and the feedback loop necessary for successful adaptive management.

  13. Detection of major river bed changes in the River Ebro (north-eastern Spain)

    NASA Technical Reports Server (NTRS)

    Espejo, R.; Torrent, J.; Roquero, C.

    1973-01-01

    The application or ERTS-1 data to determine the major river bed changes of the Ebro River in northeastern Spain is discussed. Image quality was good enough to permit a clear identification of the river course and bands MSS 5 and 7 proved to be the most useful for this purpose. Reflectance for band 5 was high due to the high sediment content of the water and sufficed to identify the river. Features like bodies of water related to old channels and depressions were only apparent in band 7.

  14. Spatiotemporal characteristics of organic contaminant concentrations and ecological risk assessment in the Songhua River, China

    EPA Science Inventory

    To control source pollution and improve water quality, an understanding of the spatiotemporal characteristics of organic contaminant concentrations in affected receiving waters is necessary. The Songhua River in northeast China is the country's third-largest domestic river and lo...

  15. Turbidity and Total Suspended Solids on the Lower Cache River Watershed, AR.

    PubMed

    Rosado-Berrios, Carlos A; Bouldin, Jennifer L

    2016-06-01

    The Cache River Watershed (CRW) in Arkansas is part of one of the largest remaining bottomland hardwood forests in the US. Although wetlands are known to improve water quality, the Cache River is listed as impaired due to sedimentation and turbidity. This study measured turbidity and total suspended solids (TSS) in seven sites of the lower CRW; six sites were located on the Bayou DeView tributary of the Cache River. Turbidity and TSS levels ranged from 1.21 to 896 NTU, and 0.17 to 386.33 mg/L respectively and had an increasing trend over the 3-year study. However, a decreasing trend from upstream to downstream in the Bayou DeView tributary was noted. Sediment loading calculated from high precipitation events and mean TSS values indicate that contributions from the Cache River main channel was approximately 6.6 times greater than contributions from Bayou DeView. Land use surrounding this river channel affects water quality as wetlands provide a filter for sediments in the Bayou DeView channel.

  16. Spatiotemporal characteristics of organic contaminant concentrations and ecological risk assessment in the Songhua River, China.

    PubMed

    Wang, Ce; Cyterski, Mike; Feng, Yujie; Gao, Peng; Sun, Qingfang

    2015-11-01

    To control source pollution and improve water quality, an understanding of the spatiotemporal characteristics of organic contaminant concentrations in affected receiving waters is necessary. The Songhua River in northeast China is the country's third-largest domestic river and loadings of organic contaminants along an industrialized section have made it the focal point of a national pollution reduction plan. In addition to water quality issues, management of the Songhua River basin must also address local economic development, aquatic ecosystem sustainability and political relationships with Russia. In three periods spanning 2006 to 2010, eight polycyclic aromatic hydrocarbons (PAHs) and eight phenols were measured in surface waters at ten monitoring sites along the river. A generalized linear model (GLM) was used to characterize water quality at different sites and time periods. Chemical concentrations of the organic compounds showed significant sinusoidal seasonal patterns and the concentrations declined significantly from 2006 to 2010, possibly due to management practices designed to control water pollution. A critical body residue analysis showed that water concentrations measured during the winter of 2007 across all monitoring sites, but especially at S1-Shaokou and S2-Songhuajiangcun, presented a high risk for fish species. The spatiotemporal characteristics of water quality and estimated ecological risks shown here add to the body of knowledge to develop policies on industrial output and pollution management strategies for the Songhua River basin. PMID:26442573

  17. Chlorinated and polycyclic aromatic hydrocarbons in riverine and estuarine sediments from Pearl River Delta, China.

    PubMed

    Mai, Bi-Xian; Fu, Jia-Mo; Sheng, Guo-Ying; Kang, Yue-Hui; Lin, Zheng; Zhang, Gan; Min, Yu-Shuan; Zeng, Eddy Y

    2002-01-01

    Spatial distribution of chlorinated hydrocarbons [chlorinated pesticides (CPs) and polychlorinated biphenyls (PCBs)] and polycyclic aromatic hydrocarbons (PAHs) was measured in riverine and estuarine sediment samples from Pearl River Delta, China, collected in 1997. Concentrations of CPs of the riverine sediment samples range from 12 to 158 ng/g, dry weight, while those of PCBs range from 11 to 486 ng/g. The CPs concentrations of the estuarine sediment samples are in the range 6-1658 ng/g, while concentrations of PCBs are in the range 10-339 ng/g. Total PAH concentration ranges from 1168 to 21,329 ng/g in the riverine sediment samples, whereas the PAH concentration ranges from 323 to 14,812 ng/g in the sediment samples of the Estuary. Sediment samples of the Zhujiang River and Macao harbor around the Estuary show the highest concentrations of CPs, PCBs, and PAHs. Possible factors affecting the distribution patterns are also discussed based on the usage history of the chemicals, hydrologic condition, and land erosion due to urbanization processes. The composition of PAHs is investigated and used to assess petrogenic, combustion and naturally derived PAHs of the sediment samples of the Pearl River Delta. In addition, the concentrations of a number of organic compounds of the Pearl River Delta samples indicate that sediments of the Zhujiang river and Macao harbor are most likely to pose biological impairment.

  18. Turbidity and Total Suspended Solids on the Lower Cache River Watershed, AR.

    PubMed

    Rosado-Berrios, Carlos A; Bouldin, Jennifer L

    2016-06-01

    The Cache River Watershed (CRW) in Arkansas is part of one of the largest remaining bottomland hardwood forests in the US. Although wetlands are known to improve water quality, the Cache River is listed as impaired due to sedimentation and turbidity. This study measured turbidity and total suspended solids (TSS) in seven sites of the lower CRW; six sites were located on the Bayou DeView tributary of the Cache River. Turbidity and TSS levels ranged from 1.21 to 896 NTU, and 0.17 to 386.33 mg/L respectively and had an increasing trend over the 3-year study. However, a decreasing trend from upstream to downstream in the Bayou DeView tributary was noted. Sediment loading calculated from high precipitation events and mean TSS values indicate that contributions from the Cache River main channel was approximately 6.6 times greater than contributions from Bayou DeView. Land use surrounding this river channel affects water quality as wetlands provide a filter for sediments in the Bayou DeView channel. PMID:27073112

  19. Hydrochemical aspects of major Pacific and caribbean rivers of colombia hydrochemical aspects of major Pacific and caribbean rivers of colombia

    NASA Astrophysics Data System (ADS)

    Restrepo, J. D.

    2003-04-01

    dissolved solids (TDS) in the Colombian rivers. Values of solute concentrations show that the Sinú and Magdalena have the highest dissolved solute content followed by the El Dique canal and Patía River. The estimates of dissolved materials exported to the Caribbean and Pacific basins are mainly controlled by water discharge. Thus, the Magdalena transports 30 x 106 t yr-1 of dissolved materials into the Caribbean. It is of the same magnitude as the Orinoco (30.5 x 106 t yr-1), ten times lower than that of the Amazon (259 x 106 t yr-1), and similar to the Parana River (38.3 x 106 t yr-1). The specific transport rate is highest in the Sinú basin, 167 t km-2 yr-1, followed by that of the Magdalena with 117 t km-2 yr-1. The more diluted rivers on the Pacific basins, Mira and Patía, have values ranging between 31 and 90 t km-2 yr-1. In Colombia, pristine fluvial systems like those draining the Pacific basins have much less PO4-3 and NO3- loads when compared to the Caribbean rivers. The Magdalena and Atrato rivers are by far the Colombian systems which contribute the highest P and N fluxes to the sea, with total phosphate and nitrate fluxes up to 186 x 103 t yr-1 and 47 x 103 t yr-1, respectively. Many causes are responsible for these high nutrient loads, including massive sewage collection in cities and towns for NH4+ and PO4-3, mainly in the Magdalena basin, and also due to fertilization of banana plantations in the lower course of the Atrato River. Many Colombian rivers, including the larger Magdalena, are affected by deforestation and rapid changes in land use, thus accelerating the transfer of particulate and dissolved organic and inorganic matter, from the river basins to the sea. Due to the magnitude of fluvial fluxes to the oceans from the Colombian rivers, the fluctuations of dissolved and suspended loads need to be monitored for a period of at least 10 years, in order to be able to quantify the influences of man’s activities and assess global climate

  20. [Affective dependency].

    PubMed

    Scantamburlo, G; Pitchot, W; Ansseau, M

    2013-01-01

    Affective dependency is characterized by emotional distress (insecure attachment) and dependency to another person with a low self-esteem and reassurance need. The paper proposes a reflection on the definition of emotional dependency and the confusion caused by various denominations. Overprotective and authoritarian parenting, cultural and socio-environmental factors may contribute to the development of dependent personality. Psychological epigenetic factors, such as early socio-emotional trauma could on neuronal circuits in prefronto-limbic regions that are essential for emotional behaviour.We also focus on the interrelations between dependent personality, domestic violence and addictions. The objective for the clinician is to propose a restoration of self-esteem and therapeutic strategies focused on autonomy.

  1. [Affective dependency].

    PubMed

    Scantamburlo, G; Pitchot, W; Ansseau, M

    2013-01-01

    Affective dependency is characterized by emotional distress (insecure attachment) and dependency to another person with a low self-esteem and reassurance need. The paper proposes a reflection on the definition of emotional dependency and the confusion caused by various denominations. Overprotective and authoritarian parenting, cultural and socio-environmental factors may contribute to the development of dependent personality. Psychological epigenetic factors, such as early socio-emotional trauma could on neuronal circuits in prefronto-limbic regions that are essential for emotional behaviour.We also focus on the interrelations between dependent personality, domestic violence and addictions. The objective for the clinician is to propose a restoration of self-esteem and therapeutic strategies focused on autonomy. PMID:23888587

  2. Modeling power-plant impacts on multipopulation systems: application of loop analysis to the Hudson River white perch population

    SciTech Connect

    Barnthouse, L.W.

    1981-12-01

    The white perch population of the Hudson River suffers unusually high mortality due to impingement and entrainment at power plants. The long-term consequences of this mortality for the Hudson River ecosystem depend in part on interactions between the white perch population and its prey, competitors, and predators, many of which are themselves subject to mortality at power plants. Size multipopulation models were analyzed, using a technique known as loop analysis, to determine how patterns of interaction affect population responses to stress and to identify the parameters that have the greatest influence on those responses. These theoretical results, together with information on life history and vulnerability to power plants for Hudson River fish and macroinvertebrate populations, were used to assess the likely effects of power plant mortality on the white perch population and its prey, competitors, and predators. The results suggest that effects of interactions with other populations are insufficient to offset the effects of entrainment and impingement on the Hudson River white perch population. The results also suggest that if mortality imposed by power plants does cause a substantial decline in the white perch population, then piscivore populations in the Hudson River should not be noticeably affected, a complementary increase in the abundance of competitors that are relatively invulnerable to power plants should occur, and a shift in the distribution of biomass within the white perch population toward the older age classes should occur.

  3. Rhenium and Molybdenum in Rivers and Estuaries.

    NASA Astrophysics Data System (ADS)

    Walker, B. D.; Peucker-Ehrenbrink, B.

    2004-12-01

    Due to their redox-sensitive nature, the geochemical cycles of Re and Mo are linked to the global organic carbon cycle. Reducing sediments constitute a globally important sink and weathering of organic-rich sediments is responsible for a large portion of the Re and - to a lesser extent - Mo flux to the oceans (Colodner et al., 1993; Jaffe et al., 2002). Riverine concentrations of Re and Mo are a function of the river basin lithology, but are also likely to be affected by anthropogenic contributions (Colodner et al., 1995). Current estimates of global natural riverine Re flux are restricted to single analyses of four major rivers, which characterize only 23%\\ of the global freshwater flux (Colodner et al., 1993). Annual variability of Re and Mo concentrations in rivers has not been studied. A single study of Re concentrations along the salinity gradient of the Amazon shelf is suggestive of conservative mixing, but scatter in the data do not allow to exclude the possibility of Re addition in the low-salinity end of the profile (Colodner et al., 1993). Careful evaluation of samples from the Hudson River estuary using a variety of extraction techniques indicates that spike-sample equilibration was not fully achieved using commonly used methods. We have therefore developed a simple, clean and efficient method of extracting Re from filtered water samples. Our method utilizes syringe filtration, prolonged heating to achieve spike-sample equilibration, batch equilibration with TEVA resin, and extraction of Re and Mo using syringe filtration. Rhenium concentrations in the Hudson, Housatonic and Connecticut rivers are 38 pM, 6.6 pM and 14 pM, respectively, much higher than the estimated global average of 2.1 pM (Colodner et al., 1993). Molybdenum concentrations are 4.6 nM, 5.5 nM, 7.8 nM, respectively. These rivers drain basins of Precambrian basement as well as predominantly Paleozoic sediments and have been substantially urbanized. Data for a salinity profile along the

  4. ENVIRONMENTAL AUDITING: The Fish Fauna of the Doubs River Prior to Completion of the Rhine-Rhone Connection

    PubMed

    Fruget; Centofanti

    1998-01-01

    / The part of the Doubs River between Montbeliard and Dole (France), i.e., downstream from the confluence with the Allan River, will be affected by the Rhine- Rhone connection project. In order to improve the understanding of the Doubs ichthyofauna, aquatic environments of the Doubs were sampled by electrofishing. Fish diversity and the presence of some rheophilic species demonstrated the good ecological quality of some stretches of the Doubs. This quality was due to alternating areas with very diversified aquatic environments (riffles, islands and side-arms, backwaters) and a considerable range of flow velocities. The differences in the structure of the fish communities of the different types of aquatic environments were more qualitative (fish species) than quantitative (number of species and number of fish). However, the mean number of fish was statistically lower in the canals (Freycinet canal and channelized part of the Allan River) than in the main course and in the backwaters. The natural parts of the Doubs (unnavigable reaches) showed the most diversified environmental structure and had the most rheophilic fish communities. Thus, the rheophilic species were well represented, but they proved also the most vulnerable to river regulation. However, the most abundant fishes throughout the Doubs River were generalists with no special requirements for food sources or spawning substrate.KEY WORDS: Fish communities; Regulation; Restoration; Floodplain; Large ship canal; Doubs River

  5. Significant human impact on the flux and δ(34)S of sulfate from the largest river in North America.

    PubMed

    Killingsworth, Bryan A; Bao, Huiming

    2015-04-21

    Riverine dissolved sulfate (SO4(2-)) flux and sulfur stable isotope composition (δ(34)S) yield information on the sources and processes affecting sulfur cycling on different spatial and temporal scales. However, because pristine preindustrial natural baselines of riverine SO4(2-) flux and δ(34)S cannot be directly measured, anthropogenic impact remains largely unconstrained. Here we quantify natural and anthropogenic SO4(2-) flux and δ(34)S for North America's largest river, the Mississippi, by means of an exhaustive source compilation and multiyear monitoring. Our data and analysis show that, since before industrialization to the present, Mississippi River SO4(2-) has increased in flux from 7.0 to 27.8 Tg SO4(2-) yr(-1), and in mean δ(34)S from -5.0‰, within 95% confidence limits of -14.8‰ to 4.1‰ (assuming normal distribution for mixing model input parameters), to -2.7 ± 1.6‰, reflecting an impressive footprint of bedrocks particular to this river basin and human activities. Our first-order modern Mississippi River sulfate partition is 25 ± 6% natural and 75% ± 6% anthropogenic sources. Furthermore, anthropogenic coal usage is implicated as the dominant source of modern Mississippi River sulfate, with an estimated 47 ± 5% and 13% of total Mississippi River sulfate due to coal mining and burning, respectively. PMID:25803121

  6. Colloids in the River Inn

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Baumann, Thomas

    2014-05-01

    In the light of an increasing number of technical applications using nanoparticles and reports of adverse effects of engineered nanoparticles, research on the occurrence and stability of particles in all compartments has to be intensified. Colloids in river water represent the geologic setting, environmental conditions, and the anthropogenic use in its catchment. The river not only acts as a sink for nanoparticles but also as the source term due to exchange in the hyporheic zone and in bank filtration setups. The concentration, size distribution and elemental composition of particles in the River Inn were studied from the source in the Swiss Alps to the river mouth at Passau. Samples were collected after each tributary from a sub-catchment and filtered on-site. The elemental composition was determined after acid digestion with ICP/MS. SEM/EDX analyses provided morphological and elemental information for single particles. A complementary chemical analysis of the river water was performed to assess the geochemical stability of indvidual particles. Particles in the upper, rural parts mainly reveal changes in the geological setting of the tributary catchments. Not unexpectedly, particles originating from crystalline rocks, were more stable than particles originating from calcareous rocks. Anthropogenic and industrial influences increase in the lower parts. This went together with a change of the size distribution, an increase of the number of organic particles, and a decrease of the microfauna. Interestingly, specific leisure activities in a sub-catchment, like extensive downhill skiing, manifest itself in the particle composition.

  7. Factors Affecting Internal Blast

    NASA Astrophysics Data System (ADS)

    Granholm, R. H.; Sandusky, H. W.; Felts, J. E.

    2007-12-01

    Internal blast refers to explosion effects in confined spaces, which are dominated by the heat output of the explosive. Theoretical temperatures and pressures may not be reached due to heat losses and incomplete gas mixing. Gas mixing can have the largest effect, potentially reducing peak quasi-static pressure by a factor of two due to lack of thermal equilibrium between products and atmosphere in the space, separate from the effect of incomplete combustion of excess fuel when that atmosphere is air. Chamber and test geometry affect gas mixing, which has been inferred through temperature and pressure measurements and compared to calculations. Late-time combustion is observed for TNT compared to HMX.

  8. Relating river geomorphology to the abundance of periphyton in New Zealand rivers

    NASA Astrophysics Data System (ADS)

    Hoyle, Jo; Hicks, Murray; Kilroy, Cathy

    2013-04-01

    Aquatic plants (including both periphyton and macrophytes) are a natural component of stream and river systems. However, abundant growth of instream plants can have detrimental impacts on the values of rivers. For example, periphyton in rivers provides basal resources for food webs and provides an important ecological service by removing dissolved nutrients and contaminants from the water column. However, high abundance of periphyton can have negative effects on habitat quality, water chemistry and biodiversity, and can reduce recreation and aesthetic values. The abundance of periphyton in rivers is influenced by a number of factors, but two key factors can be directly influenced by human activities: flow regimes and nutrient concentrations. Establishing quantitative relationships between periphyton abundance and these factors has proven to be difficult but remains an urgent priority due to the need to manage the ecological impacts of water abstraction and eutrophication of rivers worldwide. This need is particularly strong in New Zealand, where there is increasing demand for water for industry, power generation and agriculture. However, we currently have limited ability to predict the effects of changes in the mid-range flow regime on the presence/absence, abundance and composition of aquatic plants. Current water allocation limits are based on simple flow statistics, such as multiples of the median flow, but these are regional averages and can be quite unreliable on a site-specific basis. This stems largely from our limited ability to transform flow data into ecologically meaningful physical processes that directly affect plants (e.g., drag, abrasion, bed movement). The research we will present examines whether geomorphic variables, such as frequency of bed movement, are useful co-predictors in periphyton abundance-flow relationships. We collected topographic survey data and bed sediment data for 20 study reaches in the Manawatu-Wanganui region of New Zealand

  9. An extensive reef system at the Amazon River mouth.

    PubMed

    Moura, Rodrigo L; Amado-Filho, Gilberto M; Moraes, Fernando C; Brasileiro, Poliana S; Salomon, Paulo S; Mahiques, Michel M; Bastos, Alex C; Almeida, Marcelo G; Silva, Jomar M; Araujo, Beatriz F; Brito, Frederico P; Rangel, Thiago P; Oliveira, Braulio C V; Bahia, Ricardo G; Paranhos, Rodolfo P; Dias, Rodolfo J S; Siegle, Eduardo; Figueiredo, Alberto G; Pereira, Renato C; Leal, Camille V; Hajdu, Eduardo; Asp, Nils E; Gregoracci, Gustavo B; Neumann-Leitão, Sigrid; Yager, Patricia L; Francini-Filho, Ronaldo B; Fróes, Adriana; Campeão, Mariana; Silva, Bruno S; Moreira, Ana P B; Oliveira, Louisi; Soares, Ana C; Araujo, Lais; Oliveira, Nara L; Teixeira, João B; Valle, Rogerio A B; Thompson, Cristiane C; Rezende, Carlos E; Thompson, Fabiano L

    2016-04-01

    Large rivers create major gaps in reef distribution along tropical shelves. The Amazon River represents 20% of the global riverine discharge to the ocean, generating up to a 1.3 × 10(6)-km(2) plume, and extensive muddy bottoms in the equatorial margin of South America. As a result, a wide area of the tropical North Atlantic is heavily affected in terms of salinity, pH, light penetration, and sedimentation. Such unfavorable conditions were thought to imprint a major gap in Western Atlantic reefs. We present an extensive carbonate system off the Amazon mouth, underneath the river plume. Significant carbonate sedimentation occurred during lowstand sea level, and still occurs in the outer shelf, resulting in complex hard-bottom topography. A permanent near-bottom wedge of ocean water, together with the seasonal nature of the plume's eastward retroflection, conditions the existence of this extensive (~9500 km(2)) hard-bottom mosaic. The Amazon reefs transition from accretive to erosional structures and encompass extensive rhodolith beds. Carbonate structures function as a connectivity corridor for wide depth-ranging reef-associated species, being heavily colonized by large sponges and other structure-forming filter feeders that dwell under low light and high levels of particulates. The oxycline between the plume and subplume is associated with chemoautotrophic and anaerobic microbial metabolisms. The system described here provides several insights about the responses of tropical reefs to suboptimal and marginal reef-building conditions, which are accelerating worldwide due to global changes. PMID:27152336

  10. Water stress in global transboundary river basins: significance of upstream water use on downstream stress

    NASA Astrophysics Data System (ADS)

    Munia, H.; Guillaume, J. H. A.; Mirumachi, N.; Porkka, M.; Wada, Y.; Kummu, M.

    2016-01-01

    Growing population and water demand have increased pressure on water resources in various parts of the globe, including many transboundary river basins. While the impacts of upstream water use on downstream water availability have been analysed in many of these international river basins, this has not been systematically done at the global scale using coherent and comparable datasets. In this study, we aim to assess the change in downstream water stress due to upstream water use in the world’s transboundary river basins. Water stress was first calculated considering only local water use of each sub-basin based on country-basin mesh, then compared with the situation when upstream water use was subtracted from downstream water availability. We found that water stress was generally already high when considering only local water use, affecting 0.95-1.44 billion people or 33%-51% of the population in transboundary river basins. After accounting for upstream water use, stress level increased by at least 1 percentage-point for 30-65 sub-basins, affecting 0.29-1.13 billion people. Altogether 288 out of 298 middle-stream and downstream sub-basin areas experienced some change in stress level. Further, we assessed whether there is a link between increased water stress due to upstream water use and the number of conflictive and cooperative events in the transboundary river basins, as captured by two prominent databases. No direct relationship was found. This supports the argument that conflicts and cooperation events originate from a combination of different drivers, among which upstream-induced water stress may play a role. Our findings contribute to better understanding of upstream-downstream dynamics in water stress to help address water allocation problems.

  11. Water Stress in Global Transboundary River Basins: Significance of Upstream Water Use on Downstream Stress

    NASA Technical Reports Server (NTRS)

    Munia, H.; Guillaume, J. H. A.; Mirumachi, N.; Porkka,M.; Wada, Yoshihide; Kummu, M.

    2016-01-01

    Growing population and water demand have increased pressure on water resources in various parts of the globe, including many transboundary river basins. While the impacts of upstream water use on downstream water availability have been analyzed in many of these international river basins, this has not been systematically done at the global scale using coherent and comparable datasets. In this study, we aim to assess the change in downstream water stress due to upstream water use in the world's transboundary river basins. Water stress was first calculated considering only local water use of each sub-basin based on country-basin mesh, then compared with the situation when upstream water use was subtracted from downstream water availability. Wefound that water stress was generally already high when considering only local water use, affecting 0.95-1.44 billion people or 33%-51% of the population in transboundary river basins. After accounting for upstream water use, stress level increased by at least 1 percentage-point for 30-65 sub-basins, affecting 0.29-1.13 billion people. Altogether 288 out of 298 middle-stream and downstream sub-basin areas experienced some change in stress level. Further, we assessed whether there is a link between increased water stress due to upstream water use and the number of conflictive and cooperative events in the transboundary river basins, as captured by two prominent databases. No direct relationship was found. This supports the argument that conflicts and cooperation events originate from a combination of different drivers, among which upstream-induced water stress may play a role. Our findings contribute to better understanding of upstream-downstream dynamics in water stress to help address water allocation problems.

  12. Seeing the landscape for the trees: Metrics to guide riparian shade management in river catchments

    NASA Astrophysics Data System (ADS)

    Johnson, Matthew F.; Wilby, Robert L.

    2015-05-01

    Rising water temperature (Tw) due to anthropogenic climate change may have serious consequences for river ecosystems. Conservation and/or expansion of riparian shade could counter warming and buy time for ecosystems to adapt. However, sensitivity of river reaches to direct solar radiation is highly heterogeneous in space and time, so benefits of shading are also expected to be site specific. We use a network of high-resolution temperature measurements from two upland rivers in the UK, in conjunction with topographic shade modeling, to assess the relative significance of landscape and riparian shade to the thermal behavior of river reaches. Trees occupy 7% of the study catchments (comparable with the UK national average) yet shade covers 52% of the area and is concentrated along river corridors. Riparian shade is most beneficial for managing Tw at distances 5-20 km downstream from the source of the rivers where discharge is modest, flow is dominated by near-surface hydrological pathways, there is a wide floodplain with little landscape shade, and where cumulative solar exposure times are sufficient to affect Tw. For the rivers studied, we find that approximately 0.5 km of complete shade is necessary to off-set Tw by 1°C during July (the month with peak Tw) at a headwater site; whereas 1.1 km of shade is required 25 km downstream. Further research is needed to assess the integrated effect of future changes in air temperature, sunshine duration, direct solar radiation, and downward diffuse radiation on Tw to help tree planting schemes achieve intended outcomes.

  13. Contrasting discharge computation methods in riverine and tidal-affected flows in Mississippi

    USGS Publications Warehouse

    Turnipseed, D.P.

    2004-01-01

    Recent advancements in acoustic science have improved the measurement of real-time flow conditions in complex open-channel flow systems with dynamic channel geometry, velocity distribution and direction, and other gradually varying hydraulic characteristics. In the lower Pascagoula River Basin, a drainage area of about 9,500 square miles in Mississippi, riverine and tidal-affected river reaches exist that exhibit fairly steady flows during and after rainfall runoff events, and unsteady flows during low flow, tidal-affected events. Fairly steady flows can be computed usually within 5 percent by using methods developed by the USGS. Accurate measurement and computation of varied, non-uniform open-channel hydraulic streamflow conditions have historically been difficult or impossible. Acoustic and conventional methodologies to measure velocity in an open-channel riverine and tidal-affected reach have been combined to compute continuous discharge during varied, nonuniform flows by using the relations of stage and area in concert with average velocity and index velocity. Due to the unique flow characteristics on the lower Pascagoula River in Mississippi, an independent means of computing high flows based on conventional methods of a log regression of stage and discharge for a range of stages was also used. The two methods were contrasted and had good correlation. Copyright ASCE 2004.

  14. Occurrence and distribution of hexabromocyclododecane in sediments from seven major river drainage basins in China.

    PubMed

    Li, Honghua; Shang, Hongtao; Wang, Pu; Wang, Yawei; Zhang, Haidong; Zhang, Qinghua; Jiang, Guibin

    2013-01-01

    The concentrations and geographical distribution of hexabromocyclododecane (HBCD) were investigated in 37 composite surface sediments from seven major river drainage basins in China, including Yangtze River, Yellow River, Pearl River, Liaohe River, Haihe River, Tarim River and Ertix River. The detection frequency of HBCD was 54%, with the concentrations ranged from below limit of detection (LOD) to 206 ng/g dry weight. In general, the geographical distribution showed increasing trends from the upper reaches to the lower reaches of the rivers and from North China to Southeast China. Compared to other regions in the world, the average concentration of HBCD in sediments from Yangtze River drainage basin was at relatively high level, whereas those from other six river drainage basins were at lower or similar level. The highest HBCD concentration in sediment from Yangtze River Delta and the highest detection frequency of HBCD in Pearl River drainage basins suggested that the industrial and urban activities could evidently affect the HBCD distribution. HBCD diastereoisomer profiles showed that gamma-HBCD dominated in most of the sediment samples, followed by alpha- and beta-HBCD, which was consistent with those in the commercial HBCD mixtures. Further risk assessment reflected that the average inventories of HBCD were 18.3, 5.87, 3.92, 2.50, 1.77 ng/cm2 in sediments from Pearl River, Haihe River, Tarim River, Yellow River and Yangtze River, respectively. PMID:23586301

  15. Occurrence and distribution of hexabromocyclododecane in sediments from seven major river drainage basins in China.

    PubMed

    Li, Honghua; Shang, Hongtao; Wang, Pu; Wang, Yawei; Zhang, Haidong; Zhang, Qinghua; Jiang, Guibin

    2013-01-01

    The concentrations and geographical distribution of hexabromocyclododecane (HBCD) were investigated in 37 composite surface sediments from seven major river drainage basins in China, including Yangtze River, Yellow River, Pearl River, Liaohe River, Haihe River, Tarim River and Ertix River. The detection frequency of HBCD was 54%, with the concentrations ranged from below limit of detection (LOD) to 206 ng/g dry weight. In general, the geographical distribution showed increasing trends from the upper reaches to the lower reaches of the rivers and from North China to Southeast China. Compared to other regions in the world, the average concentration of HBCD in sediments from Yangtze River drainage basin was at relatively high level, whereas those from other six river drainage basins were at lower or similar level. The highest HBCD concentration in sediment from Yangtze River Delta and the highest detection frequency of HBCD in Pearl River drainage basins suggested that the industrial and urban activities could evidently affect the HBCD distribution. HBCD diastereoisomer profiles showed that gamma-HBCD dominated in most of the sediment samples, followed by alpha- and beta-HBCD, which was consistent with those in the commercial HBCD mixtures. Further risk assessment reflected that the average inventories of HBCD were 18.3, 5.87, 3.92, 2.50, 1.77 ng/cm2 in sediments from Pearl River, Haihe River, Tarim River, Yellow River and Yangtze River, respectively.

  16. Assessing the Impacts of Reservoir Regulations and Climate Variability on the Peace River Runoff and Peace-Athabasca-Delta Using a Distributed Hydrological Model

    NASA Astrophysics Data System (ADS)

    Javid, H.; Davison, B.; Princz, D. G.; Rokaya, P.; Sapriza, G.; Wheater, H. S.; Morales-Marin, L. A.; Lindenschmidt, K. E.

    2015-12-01

    Cold region river catchments functioning is permanently altered locally by the anthropogenic changes and at large scale by the climate changes. Anthropogenic changes are represented particularly by reservoirs that affect the hydrology, and thus the ecology and geomorphology of the river catchments. The Peace River Basin and Peace-Athabasca-Delta (PAD), in western Canada have been experiencing similar kind of anthropogenic changes and shifts in the hydrological regime due to the regulation of Peace River in 1960's. Since then, ice jam floods have reduced in the region, which are a very important source for replenishment of the PAD perched basins. The previous studies have regarded regulation and climate change to have equal contribution on the drying of PAD. In this study, a physically based and distributed model, MESH (Modélisation Environmentale Communautaire), that couples the Canadian Land Surface Scheme model (CLASS) and hydrological routing model (WATFLOOD), has been used to generate the runoff of Peace River under the natural flow scenario from 1970 to 2010. The reduced ice jam flooding of the PAD is mainly due to the higher freeze up stage in the lower reaches of the Peace River and declining peak flows in the spring. The former is caused by the release of water in the winter for hydropower generation and the latter is due to the filling of reservoir in the spring. Although climate variability has caused decline in summer streamflows for most of the Peace River and the PAD tributaries, as identified by the observed runoff data analysis, it is shown that the spring flows and its occurrence time would still be good enough to cause mechanical breakup of ice and overbank flooding of the PAD, if the Peace River flow was not regulated. Our results are based on the long term observed runoff analysis and the unregulated streamflows simulated by a state of the art physically based model developed by the Environment Canada.

  17. Sediment transport patterns and climate change: the downstream Tuul River case study, Northern Mongolia.

    NASA Astrophysics Data System (ADS)

    Pietroń, Jan; Jarsjö, Jerker

    2014-05-01

    Ongoing changes in the Central Asian climate including increasing temperatures can influence the hydrological regimes of rivers and the waterborne transport of sediments. Changes in the latter, especially in combination with adverse human activities, may severely impact water quality and aquatic ecosystems. However, waterborne transport of sediments is a result of complex processes and varies considerably between, and even within, river systems. There is therefore a need to increase our general knowledge about sediment transport under changing climate conditions. The Tuul River, the case site of this study, is located in the upper part of the basin of the Selenga River that is the main tributary to Lake Baikal, a UNESCO World Heritage Site. Like many other rivers located in the steppes of Northern Mongolia, the Tuul River is characterized by a hydrological regime that is not disturbed by engineered structures such as reservoirs and dams. However, the water quality of the downstream Tuul River is increasingly affected by adverse human activities - including placer gold mining. The largest contribution to the annual river discharge occurs during the relatively warm period in May to August. Typically, there are numerous rainfall events during this period that cause considerable river flow peaks. Parallel work has furthermore shown that due to climate change, the daily variability of discharge and numbers of peak flow events in the Tuul River Basin has increased during the past 60 years. This trend is expected to continue. We here aim at increasing our understanding of future sediment transport patterns in the Tuul River, specifically considering the scenario that peak flow events may become more frequent due to climate change. We use a one-dimensional sediment transport model of the downstream reach of the river to simulate natural patterns of sediment transport for a recent hydrological year. In general, the results show that sediment transport varies considerably

  18. Detection of Area Changes in River Mouthbars at the Mekong River Delta using ALOS/PALSAR data

    NASA Astrophysics Data System (ADS)

    Tanaka, A.; Uehara, K.; Tamura, T.; Saito, Y.

    2011-12-01

    Projected sea-level rise by the year 2100 would be ~1m recently and its negative impact on the coastal zone has been pointed out, particularly for mega-deltas in Asia by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC, 2007). The relative sea-level rise varies with specific conditions and processes over broad spatial and temporal scales. Therefore, long-term monitoring of geomorphological changes in coastal areas over wide areas is of highly interest and importance for coastal management. However, due to limited data availability and accessibility in developing countries, there is not enough systematic coastal monitoring. The Mekong River Delta is one of typical mega-deltas in Asia, which has a low-lying wide delta-plain located in Cambodia to South Vietnam. Sediment and water discharges of the Mekong River are controlled by the monsoon with high and low discharge in summer (wet season) and winter (dry season), respectively. Therefore, technologies such as SAR (Synthetic Aperture Radar) not affected by the cloud conditions offer potential for monitoring in the monsoon Asia region. In this study, ALOS (Advanced Land Observing Satellite) PALSAR (Phased Array type L-band SAR) data acquired over a period from December 2006 to January 2011 are analyzed to investigate the relation between the sea level and the shape of mouthbars in the Mekong River. Level-1.0 PALSAR data were processed, coregistered, and geocoded to make SAR backscatter intensity images. River mouthbars with strong backscatter, which is surrounded by the water with weak backscatter, are successfully extracted using a histogram thresholding algorithm. Estimated areas of river mouthbars, which are located at the central part of the delta and openly faced to the South China Sea, gradually increase on an annual time scale. These river mouthbars are growing to the seaward. Besides this overall increasing trend, seasonal variations of areas are observed; these correlate with

  19. The assemblage characteristics of benthic macroinvertebrates in the Yalutsangpo River, the highest major river in the world

    NASA Astrophysics Data System (ADS)

    Xu, Mengzhen; Wang, Zhaoyin; Pan, Baozhu; Yu, Guoan

    2014-09-01

    Aquatic ecosystems of highland rivers are different from those of low altitude rivers because of the specific topography and environmental parameters associated with high altitudes. Yalutsangpo, the upper course of the Brahmaputra River, is the highest major river in the world, flowing from west to east across Tibet, China and pouring into India. Macroinvertebrates were sampled from Yalutsangpo and its tributaries, the Lhasa, Niyang, and Parlong Tsangpo Rivers, from October 2009 to June 2010, to study characters of the highland aquatic ecosystem. Altogether, 110 macroinvertebrate taxa belonging to 57 families and 102 genera were identified from the basin. The biodiversity and composition of macroinvertebrate assemblages were strongly affected by altitude gradients. Local diversity represented by taxa richness and the improved Shannon-Wiener index were high at altitudes of 3,300-3,700 m, among which suitability of habitat was higher due to the better integrated environmental conditions of water temperature, dissolved oxygen, and aquatic vegetation, etc. Macroinvertebrates were grouped into shredders, scrapers, predators, collector-filterers, and collector-gatherers according to their feeding behaviors. It was found that the distributions of the functional feeding groups varied with habitat altitudes. Shredders were present at altitudes of 2,900-4,400 m, while scrapers mainly inhabited altitudes of 3,500-4,500 m, and collector-filterers preferred 3,500-4,000 m. Even though the local taxa richness was not high at each site, the taxonomic composition and density of the assemblages varied greatly among the different sites, resulting in much higher regional diversity compared to the lowland river with similar flow and substrate conditions. The regional cumulative taxa richness of Yalutsangpo decreased and more families were lost as the altitude increased. However, some families that were newly present as the altitude increased were essential for sustaining the high

  20. South Fork Holston River basin 1988 biomonitoring

    SciTech Connect

    Saylor, C.F.; Ahlstedt, S.A.

    1990-06-01

    There is concern over the effects of shifts in land use use practices on the aquatic fauna of streams in the South Fork Holston River basin in northwestern North Carolina and southwestern Virginia. Trout reproduction has noticeably declined in the Watauga River subbasin. The Watauga River and Elk River subbasins have been subjected to commercial and resort development. The Middle fork Holston River and the upper South Fork Holston River subbasins have been affected by agricultural and mining activities, respectively (Cox, 1986). To aid reclamation and management of the South Fork Holston basin, Tennessee Valley Authority (TVA) biologists conducted biomonitoring--including index of biotic integrity and macroinvertebrate sampling--on the Middle Fork Holston, South Fork Holston, Watauga, and Elk Rivers to assess cumulative impairment related to changes in habitat and pollutant loading in these subbasins. Biomonitoring can detect environmental degradation, help document problem areas, and assist in development of strategies for managing water quality. This report discusses the methods and materials and results of the biomonitoring of South Fork Holston River Basin. 13 refs., 5 figs., 12 tabs.

  1. Yazoo River Basin (Lower Mississippi River) Hydrologic Observatory

    NASA Astrophysics Data System (ADS)

    Cheng, A.; Davidson, G.; Altinakar, M.; Holt, R.

    2004-12-01

    The proposed Yazoo River Basin Hydrologic Observatory consists of the 34,000 square km Yazoo River watershed in northwestern Mississippi and a 320 km segment of the Mississippi River separated from the watershed by a manmade levee. Discharge from the basin flows from the Yazoo River into the Mississippi River north of Vicksburg, MS. Major streams within the basin include the Yazoo, Tallahatchie, Yalobusha, Coldwater, Yocona, and Big Sunflower Rivers. Four large flood control reservoirs (Arkabutla, Enid, Sardis, and Grenada) and two national forests (Delta and Holly Springs) are also located within the basin. The watershed is divided between upland forested hills and intensively cultivated lowlands. The lowland area, locally known as the "Delta", lies on the ancestral floodplain of the Mississippi River. Flooding by the Mississippi River was once a common event, but is now limited by the levee system. Abundant wetlands occupy abandoned stream channels throughout the Delta. The Yazoo River Basin has many unique features that make it an attractive site for an Hydrologic Observatory. Example features and issues of scientific interest include: 1) Extensive system of levees which have altered recharge to the regional aquifer, shifted population centers, and created backwater flooding areas. 2) Abundant wetlands with a century-long history of response to agricultural sediment and chemical fluxes. 3) Erosion of upland streams, and stream sediment loads that are the highest in the nation. 4) Groundwater mining in spite of abundant precipitation due to a regional surface clay layer that limits infiltration. 5) A history of agricultural Best Management Practices enabling evaluation of the effectiveness of such measures. 6) Large scale catfish farming with heavy reliance on groundwater. 7) Near enough to the Gulf coast to be impacted by hurricane events. 8) Already existing network of monitoring stations for stream flow, sediment-load, and weather, including complete coverage

  2. Tracing the Carbon Cycle in a Small Boreal Catchment of a Groundwater Dominated River Using the Isotopic Composition of Dissolved Inorganic Carbon

    NASA Astrophysics Data System (ADS)

    Niinikoski, P. I. A.; Karhu, J.

    2015-12-01

    Understanding the carbon cycle in river systems is particularly important in fragile catchments with agriculture, urbanization, water purification facilities and other possible contamination sources. The isotopic composition and concentration of dissolved inorganic carbon (DIC) has been used to determine carbon sinks and sources in river systems. The Vantaanjoki River, in southern Finland, is located in one of the most densely populated areas in Finland. Previous studies have shown the river having a considerable amount of groundwater - surface water interaction which leads to local groundwater being vulnerable to any contaminants released into the river. The catchment of the river has six water purification facilities, and during times of high discharge some of the waste water is released into the river without treatment. Other possible sources of contamination are urban areas, agriculture and a saw mill. In this study the isotopic composition of DIC was studied, along with the concentration of DIC in the river water, to determine the major influences in carbon balance in the river water, to see if human induced changes in the environment are affecting the carbon cycle. The highest δ13CDIC values were found in the summer, and the lowest ones in the spring. Locations of the water purification facilities or fields along the flow path did not show on the δ13CDIC values, nor in the DIC contents of the water. Similar trends in δ13CDIC values related to the variations between warm and cold seasons have been reported in other studies as well and are likely due to organic material forming and decaying in and around the river channel.

  3. Sediment transport in two mediterranean regulated rivers.

    PubMed

    Lobera, G; Batalla, R J; Vericat, D; López-Tarazón, J A; Tena, A

    2016-01-01

    Mediterranean climate is characterized by highly irregular rainfall patterns with marked differences between wet and dry seasons which lead to highly variable hydrological fluvial regimes. As a result, and in order to ensure water availability and reduce its temporal variability, a high number of large dams were built during the 20th century (more than 3500 located in Mediterranean rivers). Dams modify the flow regime but also interrupt the continuity of sediment transfer along the river network, thereby changing its functioning as an ecosystem. Within this context, the present paper aims to assess the suspended sediment loads and dynamics of two climatically contrasting Mediterranean regulated rivers (i.e. the Ésera and Siurana) during a 2-yr period. Key findings indicate that floods were responsible for 92% of the total suspended sediment load in the River Siurana, while this percentage falls to 70% for the Ésera, indicating the importance of baseflows on sediment transport in this river. This fact is related to the high sediment availability, with the Ésera acting as a non-supply-limited catchment due to the high productivity of the sources (i.e. badlands). In contrast, the Siurana can be considered a supply-limited system due to its low geomorphic activity and reduced sediment availability, with suspended sediment concentration remaining low even for high magnitude flood events. Reservoirs in both rivers reduce sediment load up to 90%, although total runoff is only reduced in the case of the River Ésera. A remarkable fact is the change of the hydrological character of the River Ésera downstream for the dam, shifting from a humid mountainous river regime to a quasi-invariable pattern, whereas the Siurana experiences the opposite effect, changing from a flashy Mediterranean river to a more constant flow regime below the dam.

  4. Silicon biogeochemical processes in a large river (Cauvery, India)

    NASA Astrophysics Data System (ADS)

    Kameswari Rajasekaran, Mangalaa; Arnaud, Dapoigny; Jean, Riotte; Sarma Vedula, V. S. S.; Nittala, S. Sarma; Sankaran, Subramanian; Gundiga Puttojirao, Gurumurthy; Keshava, Balakrishna; Cardinal, Damien

    2016-04-01

    Silicon (Si), one of the key nutrients for diatom growth in ocean, is principally released during silicate weathering on continents and then exported by rivers. Phytoplankton composition is determined by the availability of Si relative to other nutrients, mainly N and P, which fluxes in estuarine and coastal systems are affected by eutrophication due to land use and industrialization. In order to understand the biogeochemical cycle of Si and its supply to the coastal ocean, we studied a tropical monsoonal river from Southern India (Cauvery) and compare it with other large and small rivers. Cauvery is the 7th largest river in India with a basin covering 85626 sq.km. The major part of the basin (˜66%) is covered by agriculture and inhabited by more than 30 million inhabitants. There are 96 dams built across the basin. As a consequence, 80% of the historical discharge is diverted, mainly for irrigation (Meunier et al. 2015). This makes the Cauvery River a good example of current anthropogenic pressure on silicon biogeochemical cycle. We measured amorphous silica contents (ASi) and isotopic composition of dissolved silicon (δ30Si-DSi) in the Cauvery estuary, including freshwater end-member and groundwater as well as along a 670 km transect along the river course. Other Indian rivers and estuaries have also been measured, including some less impacted by anthropogenic pressure. The average Cauvery δ30Si signature just upstream the estuary is 2.21±0.15 ‰ (n=3) which is almost 1‰ heavier than the groundwater isotopic composition (1.38±0.03). The δ30Si-DSi of Cauvery water is also almost 1‰ heavier than the world river supply to the ocean estimated so far and 0.4‰ heavier than other large Indian rivers like Ganges (Frings et al 2015) and Krishna. On the other hand, the smaller watersheds (Ponnaiyar, Vellar, and Penna) adjacent to Cauvery also display heavy δ30Si-DSi. Unlike the effect of silicate weathering, the heavy isotopic compositions in the river

  5. Landscape level influence: aquatic primary production in the Colorado River of Glen and Grand canyons

    NASA Astrophysics Data System (ADS)

    Yard, M. D.; Kennedy, T.; Yackulic, C. B.; Bennett, G. E.

    2012-12-01

    Irregular features common to canyon-bound regions intercept solar incidence (photosynthetic photon flux density [PPFD: μmol m-2 s-1]) and can affect ecosystem energetics. The Colorado River in Grand Canyon is topographically complex, typical of most streams and rivers in the arid southwest. Dam-regulated systems like the Colorado River have reduced sediment loads, and consequently increased water transparency relative to unimpounded rivers; however, sediment supply from tributaries and flow regulation that affects erosion and subsequent sediment transport, interact to create spatial and temporal variation in optical conditions in this river network. Solar incidence and suspended sediment loads regulate the amount of underwater light available for aquatic photosynthesis in this regulated river. Since light availability is depth dependent (Beer's law), benthic algae is often exposed to varying levels of desiccation or reduced light conditions due to daily flow regulation, additional factors that further constrain aquatic primary production. Considerable evidence suggests that the Colorado River food web is now energetically dependent on autotrophic production, an unusual condition since large river foodwebs are typically supported by allochthonous carbon synthesized and transported from terrestrial environments. We developed a mechanistic model to account for these regulating factors to predict how primary production might be affected by observed and alternative flow regimes proposed as part of ongoing adaptive management experimentation. Inputs to our model include empirical data (suspended sediment and temperature), and predictive relationships: 1) solar incidence reaching the water surface (topographic complexity), 2) suspended sediment-light extinction relationships (optical properties), 3) unsteady flow routing model (stage-depth relationship), 4) channel morphology (photosynthetic area), and 5) photosynthetic-irradiant response for dominant algae (Cladophora

  6. Impact of Cryosphere Hydrological Changes on the River Runoff in the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Yang, D.

    2015-12-01

    The Tibetan Plateau is the headwaters of many major rivers in Asia, the change in streamflow is significant for social and economic development and natural ecology in the middle and lower reaches. Located in the alpine region, streamflow in the plateau is mainly affected by the cryosphere hydrological processes. Due to global warming in recent decades, the Tibetan Plateau is experiencing glaciers shrinking and permafrost degradation. Accelerated glacier melt led to the