Sources of suspended sediment in the Lower Roanoke River, NC

NASA Astrophysics Data System (ADS)

Jalowska, A. M.; McKee, B. A.; Rodriguez, A. B.; Laceby, J. P.

2015-12-01

The Lower Roanoke River, NC, extends 220 km from the fall line to the bayhead delta front in the Albemarle Sound. The Lower Roanoke is almost completely disconnected from the upper reaches by a series of dams, with the furthest downstream dam located at the fall line. The dams effectively restrict the suspended sediment delivery from headwaters, making soils and sediments from the Lower Roanoke River basin, the sole source of suspended sediment. In flow-regulated rivers, bank erosion, especially mass wasting, is the major contributor to the suspended matter. Additional sources of the suspended sediment considered in this study are river channel, surface soils, floodplain surface sediments, and erosion of the delta front and prodelta. Here, we examine spatial and temporal variations in those sources. This study combined the use of flow and grain size data with a sediment fingerprinting method, to examine the contribution of surface and subsurface sediments to the observed suspended sediment load along the Lower Roanoke River. The fingerprinting method utilized radionuclide tracers 210Pb (natural atmospheric fallout), and 137Cs (produced by thermonuclear bomb testing). The contributions of surface and subsurface sources to the suspended sediment were calculated with 95% confidence intervals using a Monte-Carlo numerical mixing model. Our results show that with decreasing river slope and changing hydrography along the river, the contribution of surface sediments increases and becomes a main source of sediments in the Roanoke bayhead delta. At the river mouth, the surface sediment contribution decreases and is replaced by sediments eroded from the delta front and prodelta. The area of high surface sediment contribution is within the middle and upper parts of the delta, which are considered net depositional. Our study demonstrates that floodplains, often regarded to be a sediment sink, are also a sediment source, and they should be factored into sediment, carbon and nutrient budgets.

Use of carboxylated microspheres to assess transport potential of Cryptosporidium parvum oocysts at the Russian River water supply facility, Sonoma County, California

USGS Publications Warehouse

Metge, D.W.; Harvey, R.W.; Anders, R.; Rosenberry, D.O.; Seymour, D.; Jasperse, James

2007-01-01

Carboxylated microspheres were employed as surrogates to assess the transport potential of Cryptosporidium parvumoocysts during forced- and natural-gradient tests conducted in July and October 2004. The tests involved poorly-sorted, near-surface sediments where groundwater is pumped from an alluvial aquifer underlying the Russian River, Sonoma County, CA. In an off channel infiltration basin and within the river, a mixture (2-, 3-, and 5- ??m diameters) of fluorescently-labeled carboxylated microspheres and bromide tracers were used in two injection and recovery test to assess sediment removal efficiency for the microspheres. Bottom sediments varied considerably in their filtration efficiency for Cryptosporidium.

Embryotoxicity and genotoxicity evaluation of sediments from Yangtze River estuary using zebrafish (Danio rerio) embryos.

PubMed

Li, Qian; Chen, Ling; Liu, Li; Wu, Lingling

2016-03-01

Sediments function both as a sink and a source of pollutants in aquatic ecosystems and may impose serious effects on benthic organisms and human health. As one of the largest estuaries in the world, the Yangtze River estuary suffers from abundant wastewater from the coastal cities. In this study, the zebrafish (Danio rerio) embryos were employed in the fish embryo test and a comet assay to evaluate the embryotoxicity and genotoxicity of the sediments from the Yangtze River estuary, respectively. Results showed that the sediments from the Yangtze River estuary significantly increased mortality, induced development abnormalities, and reduced hatching rate and heart rate of zebrafish embryos after 96 h of exposure. Significant genotoxicity was observed in the samples relative to the controls. Relatively low-level embryotoxicity and genotoxicity of sediments were found in the Yangtze River compared with other river systems. Toxic responses were also discussed in relation to the analyzed organic contaminants in sediments. More attention should be paid to non-priority pollutant monitoring in the Yangtze River estuary.

Predicting the distribution of bed material accumulation using river network sediment budgets

NASA Astrophysics Data System (ADS)

Wilkinson, Scott N.; Prosser, Ian P.; Hughes, Andrew O.

2006-10-01

Assessing the spatial distribution of bed material accumulation in river networks is important for determining the impacts of erosion on downstream channel form and habitat and for planning erosion and sediment management. A model that constructs spatially distributed budgets of bed material sediment is developed to predict the locations of accumulation following land use change. For each link in the river network, GIS algorithms are used to predict bed material supply from gullies, river banks, and upstream tributaries and to compare total supply with transport capacity. The model is tested in the 29,000 km2 Murrumbidgee River catchment in southeast Australia. It correctly predicts the presence or absence of accumulation in 71% of river links, which is significantly better performance than previous models, which do not account for spatial variability in sediment supply and transport capacity. Representing transient sediment storage is important for predicting smaller accumulations. Bed material accumulation is predicted in 25% of the river network, indicating its importance as an environmental problem in Australia.

The dominant erosion processes supplying fine sediment to three major rivers in tropical Australia, the Daly (NT), Mitchell (Qld) and Flinders (Qld) Rivers

NASA Astrophysics Data System (ADS)

Caitcheon, Gary G.; Olley, Jon M.; Pantus, Francis; Hancock, Gary; Leslie, Christopher

2012-05-01

The tropics of northern Australia have received relatively little attention with regard to the impact of soil erosion on the many large river systems that are an important part of Australia's water resource, especially given the high potential for erosion when long dry seasons are followed by intense wet season rain. Here we use 137Cs concentrations to determine the erosion processes supplying sediment to two major northern Australian Rivers; the Daly River (Northern Territory), and the Mitchell River (Queensland). We also present data from five sediment samples collected from a 100 km reach of the Cloncurry River, a major tributary of the Flinders River (Queensland). Concentrations of 137Cs in the surface soil and subsurface (channel banks and gully) samples were used to derive 'best fit' probability density functions describing their distributions. These modelled distributions are then used to estimate the relative contribution of these two components to the river sediments. Our results are consistent with channel and gully erosion being the dominant source of sediment, with more than 90% of sediment transported along the main stem of these rivers originating from subsoil. We summarize the findings of similar studies on tropical Australian rivers and conclude that the primary source of sediment delivered to these systems is gully and channel bank erosion. Previously, as a result of catchment scale modelling, sheet-wash and rill erosion was considered to be the major sediment source in these rivers. Identifying the relative importance of sediment sources, as shown in this paper, will provide valuable information for land management planning in the region. This study also reinforces the importance of testing model predictions before they are used to target investment in remedial action.

Static renewal tests using Anodonta imbecillis (freshwater mussels). Anodonta imbecillis QA test 4, Clinch River-Environmental Restoration Program (CR-ERP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

1994-12-31

Toxicity testing of split whole sediment samples using juvenile freshwater mussels (Anodonta imbecillis) was conducted by TVA to provide a quality assurance mechanism for test organisms quality and overall performance of the test being conducted by CR-ERP personnel as part of the CR-ERP biomonitoring study of Clinch River sediments. Testing of sediment samples collected September 8 from Poplar Creek Miles 6.0 and 1.0 was conducted September 13--22, 1994. Results from this test showed no toxicity (survival effects) to fresh-water mussels during a 9-day exposure to the sediments. Attachments to this report include: Chain of custody form -- original; Toxicity testmore » bench sheets; Ammonia analysis request and results; and Meter calibration log sheets.« less

Comparison of single extraction procedures and the application of an index for the assessment of heavy metal bioavailability in river sediments.

PubMed

Sakan, Sanja; Popović, Aleksandar; Škrivanj, Sandra; Sakan, Nenad; Đorđević, Dragana

2016-11-01

Metals in sediments are present in different chemical forms which affect their ability to transfer. The objective of this body of work was to compare different extraction methods for the bioavailability evaluation of some elements, such as Ba, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, V and Zn from Serbian river sediments. A bioavailability risk assessment index (BRAI) was used for the quantification of heavy metal bioavailability in the sediments. Actual and potential element availability was assessed by single extractions with mild (CaCl 2 and CH 3 COONH 4 ) and acidic (CH 3 COOH) extractants and complexing agents (EDTA). Aqua regia extraction was used for the determination of the pseudo-total element content in river sediments. In different single extraction tests, higher extraction of Cd, Cu, Zn and Pb was observed than for the other elements. The results of the single extraction tests revealed that there is a considerable chance of metal leaching from the sediments assessed in this study. When the BRAI was applied, the results showed a high risk of heavy metal bioavailability in Serbian river sediments.

Variation of nonylphenol-degrading gene abundance and bacterial community structure in bioaugmented sediment microcosm.

PubMed

Wang, Zhao; Yang, Yuyin; Sun, Weimin; Dai, Yu; Xie, Shuguang

2015-02-01

Nonylphenol (NP) can accumulate in river sediment. Bioaugmentation is an attractive option to dissipate heavy NP pollution in river sediment. In this study, two NP degraders were isolated from crude oil-polluted soil and river sediment. Microcosms were constructed to test their ability to degrade NP in river sediment. The shift in the proportion of NP-degrading genes and bacterial community structure in sediment microcosms were characterized using quantitative PCR assay and terminal restriction fragment length polymorphism analysis, respectively. Phylogenetic analysis indicated that the soil isolate belonged to genus Stenotrophomonas, while the sediment isolate was a Sphingobium species. Both of them could almost completely clean up a high level of NP in river sediment (150 mg/kg NP) in 10 or 14 days after inoculation. An increase in the proportion of alkB and sMO genes was observed in sediment microcosms inoculated with Stenotrophomonas strain Y1 and Sphingobium strain Y2, respectively. Moreover, bioaugmentation using Sphingobium strain Y2 could have a strong impact on sediment bacterial community structure, while inoculation of Stenotrophomonas strain Y1 illustrated a weak impact. This study can provide some new insights towards NP biodegradation and bioremediation.

The response of source-bordering aeolian dunefields to sediment-supply changes 1: Effects of wind variability and river-valley morphodynamics

USGS Publications Warehouse

Sankey, Joel B.; Kasprak, Alan; Caster, Joshua; East, Amy; Fairley, Helen C.

2018-01-01

Source-bordering dunefields (SBDs), which are primarily built and maintained with river-derived sediment, are found in many large river valleys and are currently impacted by changes in sediment supply due to climate change, land use changes, and river regulation. Despite their importance, a physically based, applied approach for quantifying the response of SBDs to changes in sediment supply does not exist. To address this knowledge gap, here we develop an approach for quantifying the geomorphic responses to sediment-supply alteration based on the interpretation of dunefield morphodynamics from geomorphic change detection and wind characteristics. We use the approach to test hypotheses about the response of individual dunefields to variability in sediment supply at three SBDs along the Colorado River in Grand Canyon, Arizona, USA during the 11 years between 2002 and 2013 when several river floods rebuilt some river sandbars and channel margin deposits that serve as sediment source areas for the SBDs. We demonstrate that resupply of fluvially sourced aeolian sediment occurred at one of the SBDs, but not at the other two, and attribute this differential response to site-specific variability in geomorphology, wind, and sediment source areas. The approach we present is applied in a companion study to shorter time periods with high-resolution topographic data that bracket individual floods in order to infer the resupply of fluvially sourced aeolian sediment to SBDs by managed river flows. Such an applied methodology could also be useful for measuring sediment connectivity and anthropogenic alterations of connectivity in other coupled fluvial-aeolian environments.

The response of source-bordering aeolian dunefields to sediment-supply changes 1: Effects of wind variability and river-valley morphodynamics

NASA Astrophysics Data System (ADS)

Sankey, Joel B.; Kasprak, Alan; Caster, Joshua; East, Amy E.; Fairley, Helen C.

2018-06-01

Source-bordering dunefields (SBDs), which are primarily built and maintained with river-derived sediment, are found in many large river valleys and are currently impacted by changes in sediment supply due to climate change, land use changes, and river regulation. Despite their importance, a physically based, applied approach for quantifying the response of SBDs to changes in sediment supply does not exist. To address this knowledge gap, here we develop an approach for quantifying the geomorphic responses to sediment-supply alteration based on the interpretation of dunefield morphodynamics from geomorphic change detection and wind characteristics. We use the approach to test hypotheses about the response of individual dunefields to variability in sediment supply at three SBDs along the Colorado River in Grand Canyon, Arizona, USA during the 11 years between 2002 and 2013 when several river floods rebuilt some river sandbars and channel margin deposits that serve as sediment source areas for the SBDs. We demonstrate that resupply of fluvially sourced aeolian sediment occurred at one of the SBDs, but not at the other two, and attribute this differential response to site-specific variability in geomorphology, wind, and sediment source areas. The approach we present is applied in a companion study to shorter time periods with high-resolution topographic data that bracket individual floods in order to infer the resupply of fluvially sourced aeolian sediment to SBDs by managed river flows. Such an applied methodology could also be useful for measuring sediment connectivity and anthropogenic alterations of connectivity in other coupled fluvial-aeolian environments.

Toxicity of bed sediments from the Niagara River Area of Concern and tributaries, New York, to Chironomus dilutus and Hyalella azteca, 2014-15

USGS Publications Warehouse

George, Scott D.; Baldigo, Barry P.; Duffy, Brian T.

2016-09-20

The Niagara River was designated as an Area of Concern in 1987 on both the United States and Canadian sides of the international boundary line because past industrial discharges and hazardous waste sites had caused extensive degradation of aquatic habitats. The degradation of the “benthos”, or the benthic macroinvertebrate community, was identified as one of seven beneficial use impairments caused by contaminated bed sediments. The U.S. Geological Survey and the New York State Department of Environmental Conservation, in cooperation with the U.S. Environmental Protection Agency, conducted a study in 2014 and 2015 to gather more extensive data on (a) the toxicity of bed sediments and (b) the status of macroinvertebrate communities on the main stem and tributaries of the Niagara River. This report addresses the first component of that study (toxicity of bed sediments), and summarizes results from laboratory toxicity tests that compare the survival and growth of two macroinvertebrate species between bed sediments from study sites and laboratory controls. Sediment toxicity was negligible at most sites, however poor performance of one or both test species in bed sediments from several tributary sites suggests that the quality of sediments may be adversely affecting benthic macroinvertebrate communities in some tributaries to the Niagara River.

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 water; (3) to develop site-specific thresholds for toxicity of Zn and Cu in stream water; and (4) to develop models of the contributions of Cu and Zn to toxicity of stream water, which may be used to characterize toxicity before and after planned remediation efforts. We evaluated the toxicity of metal-contaminated sediments by conducting sediment toxicity tests with two species of benthic invertebrates, the midge, Chironomus tentans. and the amphipod, Hyalella azteca. Laboratory toxicity tests with both taxa, exposed to fine stream-bed sediments collected in September 1997, showed some evidence of sediment toxicity, as survival of midge larvae in sediments from Cement Creek (C48) and lower Mineral Creek (M34), and growth of amphipods in sediments from these sites and three Animas River sites (A68, Animas at Silverton; A72, Animas below Silverton, and A73, Animas at Elk Park) were significantly reduced compared to a reference site, South Mineral Creek (SMC) . Amphipods were also exposed to site water and fine stream-bed sediment, separately and in combination, during the late summer low flow period (August-September) of 1998. In these studies, stream water, with no sediment present, from all five sites tested (same sites as above, except C48) caused 90% to 100% mortality of amphipods. In contrast, significant reductions in survival of amphipods occurred at two sites (A72 and SMC) in exposures with field-collected sediment plus stream water, and at only one site (A72) in exposures with sediments and clean overlying water. Concentrations of Zn, Pb, Cu, and Cd were high in both sediment and pore water (interstitial water) from most sites tested, but greatest sediment toxicity was apparently associated with greater concentrations of Fe and/or Al in sediments. These results suggest that fine stream-bed sediments of the more contaminated stream reaches of the upper Animas River watershed are toxic to benthic invertebrates, but that these impacts are less serious than tox

Model testing of radioactive contamination by 90Sr, 137Cs and 239,240Pu of water and bottom sediments in the Techa River (Southern Urals, Russia).

PubMed

Kryshev, I I; Boyer, P; Monte, L; Brittain, J E; Dzyuba, N N; Krylov, A L; Kryshev, A I; Nosov, A V; Sanina, K D; Zheleznyak, M I

2009-03-15

This paper presents results of testing models for the radioactive contamination of river water and bottom sediments by (90)Sr, (137)Cs and (239,240)Pu. The scenario for the model testing was based on data from the Techa River (Southern Urals, Russia), which was contaminated as a result of discharges of liquid radioactive waste into the river. The endpoints of the scenario were model predictions of the activity concentrations of (90)Sr, (137)Cs and (239,240)Pu in water and bottom sediments along the Techa River in 1996. Calculations for the Techa scenario were performed by six participant teams from France (model CASTEAUR), Italy (model MARTE), Russia (models TRANSFER-2, CASSANDRA, GIDRO-W) and Ukraine (model RIVTOX), all using different models. As a whole, the radionuclide predictions for (90)Sr in water for all considered models, (137)Cs for MARTE and TRANSFER-2, and (239,240)Pu for TRANSFER-2 and CASSANDRA can be considered sufficiently reliable, whereas the prediction for sediments should be considered cautiously. At the same time the CASTEAUR and RIVTOX models estimate the activity concentrations of (137)Cs and (239,240)Pu in water more reliably than in bottom sediments. The models MARTE ((239,240)Pu) and CASSANDRA ((137)Cs) evaluated the activity concentrations of radionuclides in sediments with about the same agreement with observations as for water. For (90)Sr and (137)Cs the agreement between empirical data and model predictions was good, but not for all the observations of (239,240)Pu in the river water-bottom sediment system. The modelling of (239,240)Pu distribution proved difficult because, in contrast to (137)Cs and (90)Sr, most of models have not been previously tested or validated for plutonium.

Data on sediment quality and concentrations of polychlorinated biphenyls from the Lower Neponset River, Massachusetts, 2002-03

USGS Publications Warehouse

Breault, Robert F.; Cooke, Matthew G.; Merrill, Michael

2004-01-01

The U.S. Geological Survey, in cooperation with the Massachusetts Executive Office of Environmental Affairs Department of Fish and Game Riverways Program, and the U.S. Environmental Protection Agency, studied sediment and water quality in the lower Neponset River, which is a tributary to Boston Harbor. Grab and core samples of sediment were tested for elements and organic compounds including polyaromatic hydrocarbons, organochlorine pesticides, and polychlorinated biphenyls. Physical properties of sediment samples, including grain size, were also measured. Selected sediment-core samples were tested for reactive sulfides and metals by means of the toxicity characteristic leaching procedure, which are sediment-disposal-related tests. Water quality, with respect to polychlorinated biphenyl contamination, was determined by testing samples collected by PISCES passive-water-column samplers for polychlorinated biphenyl congeners. Total concentrations of polychlorinated biphenyls were calculated by congener and by Aroclor.

Static renewal tests using Anodonta imbecillis (freshwater mussels). Anodonta imbecillis QA test 3, Clinch River-Environmental Restoration Program (CR-ERP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

1994-12-31

Toxicity testing of split whole sediment samples using juvenile freshwater mussels (Anodonta imbecillis) was conducted by TVA to provide a quality assurance mechanism for test organism quality and overall performance of the test being conducted by CR-ERP personnel as part of the CR-ERP biomonitoring study of Clinch River sediments. Testing of sediment samples collected May 5 from Poplar Creek Miles 6.0 and 2.9 was conducted from May 10--19, 1994. Results from this test showed no toxicity (survival effects) to fresh-water mussels during a 9-day exposure to the sediments. Attachments to this report include: Chain of custody form -- original; Toxicitymore » test bench sheets; Ammonia analysis request and results; Meter calibration log sheets; and Training documentation forms.« less

Static renewal tests using Anodonta imbecillis (freshwater mussels). Anodonta imbecillis QA test 2, Clinch River-Environmental Restoration Program (CR-ERP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

1993-12-31

Toxicity testing of split whole sediment samples using juvenile freshwater mussels (Anodonta imbecillis) was conducted by TVA to provide a quality assurance mechanism for test organism quality and overall performance of the test being conducted by CR-ERP personnel as part of the CR-ERP biomonitoring study of Clinch River sediments. Testing of sediment samples collected August 14 from Poplar Creek Miles 6.0 and 4.3 was conducted from August 24--September 2, 1993. Results from this test showed no toxicity (survival effects) to fresh-water mussels during a 9-day exposure to the sediments. Attachments to this report include: Chain of custody form -- original;more » Toxicity test bench sheets and statistical analyses; and Ammonia analysis request and results.« less

Fine sediment trapping in river lateral cavities

NASA Astrophysics Data System (ADS)

Juez, C.; Maechler, G.; Schleiss, A. J.; Franca, M. J.

2016-12-01

River restoration is nowadays a major issue in the field of hydraulics. The natural course and geometry of the rivers have been artificially changed by human activities for different purposes (land gaining, flood protection, agriculture). From a morphologic point of view, channelized rivers often display a straight path and monotonous river banks. This is in contradiction with natural morphology, where a high diversity can be found across the channel path (meanders) and the banks (pools, riffles). One way to restore rivers consist of transforming the artificial banks by adding macro-roughness elements in the lateral river banks (also called cavities and lateral embayments). The creation of irregularities on the banks causes new flow patterns that diversify the river habitat. However, these lateral cavities may be also responsible of the change of the river morphology, since they may trap the fine sediments travelling within the water. This is particularly important in glacier-fed streams such as the upper Rhone River in Switzerland. These are charged with fine sediments resulting from the erosion of the underlying glaciers bottom. The creation of lateral cavities may affect the sediment and morphological equilibrium of the river since these may trap sediments. This work aims to study the influence of the lateral cavities on the transport of fine sediments in the main channel. A set of laboratory experiments were done which covered a wide range of rectangular cavity configurations. Key parameters such as the flow discharge, the aspect ratio of the cavities and the initial sediment concentration were tested. Surface PIV, sediment samples and turbidity temporal records were collected during the experiments. The trapping efficiency of the cavities and the associated flow patterns were analyzed. The resulting conclusions provide a useful information for the future design of river restoration projects.

Suspended sediment in the St. Francis River at St. Francis, Arkansas, 1986-95

USGS Publications Warehouse

Green, W. Reed; Barks, C. Shane; Hall, Alan P.

2000-01-01

Daily suspended-sediment concentrations were analyzed from the St. Francis River at St. Francis, Arkansas during 1986 through 1995. Suspended-sediment particle size distribution was measured in selected samples from 1978 through 1998. These data are used to assess changes in suspended-sediment concentrations and loads through time. Suspended-sediment concentrations were positively related to discharge. At higher flows, percent silt-clay was negatively related to discharge. Nonparametric trend analysis (Mann-Kendall test) of suspended-sediment concentration over the period of record indicated a slight decrease in concentration. Flow-adjusted residuals of suspended-sediment concentration also decreased slightly through the same period. No change was identified in annual suspended-sediment load or annual flow-weighted concentration. Continued monitorig of daily-suspended-sediment concentrations at this site and others, and similar data analysis at other sites where data are available will provide a better understanding of sediment transport withint the St. Francis River.

Morphodynamic Assessment of West Bay Sediment Diversion: A Land Building Analogue for the Lower Mississippi River Delta

NASA Astrophysics Data System (ADS)

Khadka, A. K.; Meselhe, E. A.; Allison, M. A.; Yuill, B.

2016-12-01

Wetlands of the Mississippi River Deltaic Plain have undergone enormous land loss in the last century due to natural and anthropogenic factors such as subsidence and canal building. After years of feasibility research, Lower Mississippi River (LMR) diversions have been authorized as a tool to build and sustain regional wetlands. To this end, the West Bay sediment diversion (WBD), located on the west bank of the Mississippi River at river kilometer 7.6 above Head of Passes, was constructed in 2003 with a project goal of building 4,000 hectares of wetlands in the estuarine receiving . This sediment diversion serves as splay analogue to calibrate predictive morphologic models that are being used to test the effects of proposed land building sediment diversions in the LMR. We developed a two-dimensional Delft3D model for the WBD area which includes the main channel of the Mississippi River, the diversion cut, and the receiving basin. The model is extensively calibrated and validated for hydrodynamics and morphodynamics in the main river stem, diversion cut and receiving basin using an array of field observations. The model provides quantitative information on the capture efficiency and grain size of LMR sediment diverted through the diversion. Further, the model provides insights into the morphological evolution and sediment capture efficiency of the receiving basin with diversion operation. Sensitivity tests were performed to examine the impacts of dominant drivers (wind, wave and sediment retention islands) on land building processes. The calibrated WBD model is helpful to establish appropriate parameterizations (e.g., substrate design) for the development of future numerical models designed to investigate the morphological response of receiving basins to the proposed diversions located along the LMR and in similar deltaic environments. Keywords: Numerical Modeling, Morphodynamics, Sediment Diversions, Lower Mississippi River, Delft3D,

Studying toxicity

USGS Publications Warehouse

Elkus, A.; LeBlanc, L.; Kim, C.; Van Beneden, R.; Mayer, G.

2006-01-01

With funding from the George Mitchell Center for the Environment at the University of Maine, a team of scientists used a simple laboratory-based sediment resuspension design, and two well-established aquatic toxicology models, fathead minnows (Pimephales promelas) and zebrafish (Danio rerio), to evaluate if resuspension of Penobscot river sediment significantly elevates the toxicity of river water and to provide preliminary information on the types of chemicals likely to desorb during resuspension. The group collected sediments from two sites with known chemical contamination downstream of the Great Works and Veazie dams. The sediments were examined to determine the dynamics of PAH desorption and degradation under different resuspension frequencies. The scientists used clarified water from resuspension experiments for toxicity tests with the water-flea Ceriodaphnia dubia, and other aquatic test organisms to infer toxicity from sediments from northern California rivers. Data from the study will help ascertain whether metals and/or xenoestrogens are present in the desorption water and give insight into possible avenues of sediment remediation.

Toxicity and bioavailability of metals in the Missouri River adjacent to a lead refinery

USGS Publications Warehouse

Chapman, Duane C.; Allert, Ann L.; Fairchild, James F.; May, Thomas W.; Schmitt, Christopher J.; Callahan, Edward V.

2001-01-01

This study is an evaluation of the potential environmental impacts of contaminated groundwater from the ASARCO metals refining facility adjacent to the Missouri River in Omaha, Nebraska. Surface waters, sediments, and sediment pore waters were collected from the Burt-Izard drain, which transects the facility, and from the Missouri River adjacent to the facility. Groundwater was also collected from the facility. Waters and sediments were analyzed for inorganic contaminants, and the toxicity of the waters was evaluated with the Ceriodaphnia dubia 7-day test. Concentrations of several elemental contaminants were highly elevated in the groundwater, but not in river sediment pore waters. Lead concentrations were moderately elevated in whole sediment at one site, but lead concentrations in pore waters were low due to apparent sequestration by acid-volatile sulfides. The groundwater sample was highly toxic to C. dubia, causing 100% mortality. Even at the lowest groundwater concentration tested (6.25%) C. dubia survival was reduced; however, at that concentration, reproduction was not significantly different from upstream porewater reference samples. Sediment pore waters were not toxic, except reproduction in pore water collected from one downstream site was somewhat reduced. The decrease in reproduction could not be attributed to measured elemental contaminants.

Sediment-contact fish embryo toxicity assay with Danio rerio to assess particle-bound pollutants in the Tietê River Basin (São Paulo, Brazil).

PubMed

Rocha, Paula Suares; Bernecker, Conny; Strecker, Ruben; Mariani, Carolina Fiorillo; Pompêo, Marcelo Luiz Martins; Storch, Volker; Hollert, Henner; Braunbeck, Thomas

2011-10-01

The Tietê River and its tributary Pinheiros River receive a highly complex organic and inorganic pollutants load from sanitary sewage and industrial sources, as well as agricultural and agroindustrial activities. The aim of the present study was to evaluate the embryotoxic and teratogenic effects of sediments from selected locations in the Tietê River Basin by means of the sediment contact embryo toxicity assay with Danio rerio, in order to provide a comprehensive and realistic insight into the bioavailable hazard potential of these sediment samples. Lethal and sub-lethal effects were recorded, and high embryo toxicity could be found in the samples not only in the vicinity of the megacity São Paulo (Billings reservoir and Pinheiros River samples), but also downstream (in the reservoirs Barra Bonita, Promissão and Três Irmãos). Results confirm that most toxicity is due to the discharges of the metropolitan area of São Paulo. However, they also indicate additional sources of pollutants along the river course, probably from industrial, agricultural and agroindustrial residues, which contribute to the degradation of each area. The sediment contact fish embryo test showed to be powerful tool to detect embryo toxicity in sediments, not only by being a sensitive method, but also for taking into account bioavailability. This test provides an ecological highly realistic and relevant exposure scenario, and should therefore be added in ecotoxicological sediment quality assessments. Copyright © 2011 Elsevier Inc. All rights reserved.

Effects of contaminants in dredge material from the Lower Savannah River

USGS Publications Warehouse

Winger, P.V.; Lasier, P.J.; White, D.H.; Seginak, J.T.

2000-01-01

Contaminants entering aquatic systems from agricultural, industrial, and municipal activities are generally sequestered in bottom sediments. The environmental significance of contaminants associated with sediments dredged from Savannah Harbor, Georgia, USA, are unknown. To evaluate potential effects of contaminants in river sediments and sediments dredged and stored in upland disposal areas on fish and wildlife species, solid-phase sediment and sediment pore water from Front River, Back River, an unnamed Tidal Creek on Back River, and Middle River of the distributary system of the lower Savannah River were tested for toxicity using the freshwater amphipod Hyalella azteca. In addition, bioaccumulation of metals from sediments collected from two dredge-disposal areas was determined using the freshwater oligochaete Lumbriculus variegatus. Livers from green-winged teals (Anas crecca) and lesser yellowlegs (Tringa flavipes) foraging in the dredge-spoil areas and raccoons (Procyon lotor) from the dredge-disposal/river area and an upland site were collected for metal analyses. Survival of H. azteca was not reduced in solid-phase sediment exposures, but was reduced in pore water from several locations receiving drainage from dredge-disposal areas. Basic water chemistry (ammonia, alkalinity, salinity) was responsible for the reduced survival at several sites, but PAHs, metals, and other unidentified factors were responsible at other sites. Metal residues in sediments from the Tidal Creek and Middle River reflected drainage or seepage from adjacent dredge-disposal areas, which could potentially reduce habitat quality in these areas. Trace metals increased in L. variegatus exposed in the laboratory to dredge-disposal sediments; As, Cu, Hg, Se, and Zn bioaccumulated to concentrations higher than those in the sediments. Certain metals (Cd, Hg, Mo, Se) were higher in livers of birds and raccoons than those in dredge-spoil sediments suggesting bioavailability. Cadmium, Ct, Hg, Pb, and Se in livers from raccoons collected near the river and dredge-disposal areas were significantly higher than those of raccoons from the upland control site. Evidence of bioaccumulation from laboratory and field evaluations and concentrations in sediments from dredge-disposal areas and river channels demonstrated that some metals in the dredge-disposal areas are mobile and biologically available. Drainage from dredge-disposal areas may be impacting habitat quality in the river, and fish and wildlife that feed and nest in the disposal area pm the lower Savannah River may be at risk from metal contamination.

The use of innovative screening-level techniques for the bioassessment of estuarine sediments at U.S. Army Aberdeen Proving Ground, MD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neubauer, R.J.; Thebeau, L.; Paul, J.

1994-12-31

The US Army Aberdeen Proving Ground (APG) is a primarily undeveloped installation on the upper Chesapeake bay in Maryland. The bush and Gunpowder Rivers are two sub-estuaries that run through the installation before emptying into the Chesapeake Bay. Past activities at EA APG include pilot-scale chemical agent manufacturing, munitions testing, smoke/incendiary manufacturing, domestic and rubble landfilling, and disposal of chemical warfare agents as well as other materials. It was determined that if contamination of the Gunpowder River exists from these previous activities on EA APG it was most likely to be found in the sediments. The initial phase was tomore » conduct a sediment survey of the river to determine the spatial distribution of sediment types and the suitability of the benthos for the proposed methodologies. The second phase was to combine innovative screening-level investigative methodologies as well as sediment chemical and physical analyses into one survey of the benthos and sediments of the Gunpowder River. This phase used the Microtox luminescent bioassay and Daphnia magna IQ Toxicity Test, Surface and Profile Image (SPI) photography, analysis of sediment physical characteristics, and limited chemical analysis to identify locations that warrant a more focused investigation.« less

Simulation of relationship between river discharge and sediment yield in the semi-arid river watersheds

NASA Astrophysics Data System (ADS)

Khaleghi, Mohammad Reza; Varvani, Javad

2018-02-01

Complex and variable nature of the river sediment yield caused many problems in estimating the long-term sediment yield and problems input into the reservoirs. Sediment Rating Curves (SRCs) are generally used to estimate the suspended sediment load of the rivers and drainage watersheds. Since the regression equations of the SRCs are obtained by logarithmic retransformation and have a little independent variable in this equation, they also overestimate or underestimate the true sediment load of the rivers. To evaluate the bias correction factors in Kalshor and Kashafroud watersheds, seven hydrometric stations of this region with suitable upstream watershed and spatial distribution were selected. Investigation of the accuracy index (ratio of estimated sediment yield to observed sediment yield) and the precision index of different bias correction factors of FAO, Quasi-Maximum Likelihood Estimator (QMLE), Smearing, and Minimum-Variance Unbiased Estimator (MVUE) with LSD test showed that FAO coefficient increases the estimated error in all of the stations. Application of MVUE in linear and mean load rating curves has not statistically meaningful effects. QMLE and smearing factors increased the estimated error in mean load rating curve, but that does not have any effect on linear rating curve estimation.

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.

Heavy metals relationship with water and size-fractionated sediments in rivers using canonical correlation analysis (CCA) case study, rivers of south western Caspian Sea.

PubMed

Vosoogh, Ali; Saeedi, Mohsen; Lak, Raziyeh

2016-11-01

Some pollutants can qualitatively affect aquatic freshwater such as rivers, and heavy metals are one of the most important pollutants in aquatic fresh waters. Heavy metals can be found in the form of components dissolved in these waters or in compounds with suspended particles and surface sediments. It can be said that heavy metals are in equilibrium between water and sediment. In this study, the amount of heavy metals is determined in water and different sizes of sediment. To obtain the relationship between heavy metals in water and size-fractionated sediments, a canonical correlation analysis (CCA) was utilized in rivers of the southwestern Caspian Sea. In this research, a case study was carried out on 18 sampling stations in nine rivers. In the first step, the concentrations of heavy metals (Cu, Zn, Cr, Fe, Mn, Pb, Ni, and Cd) were determined in water and size-fractionated sediment samples. Water sampling sites were classified by hierarchical cluster analysis (HCA) utilizing squared Euclidean distance with Ward's method. In addition, for interpreting the obtained results and the relationships between the concentration of heavy metals in the tested river water and sample sediments, canonical correlation analysis (CCA) was utilized. The rivers were grouped into two classes (those having no pollution and those having low pollution) based on the HCA results obtained for river water samples. CCA results found numerous relationships between rivers in Iran's Guilan province and their size-fractionated sediments samples. The heavy metals of sediments with 0.038 to 0.125 mm size in diameter are slightly correlated with those of water samples.

Sediment toxicity in Savannah Harbor

USGS Publications Warehouse

Winger, P.V.; Lasier, P.J.

1995-01-01

Savannah Harbor, located near the mouth of the Savannah River, Georgia and South Carolina, is impacted by industrial and municipal effluents. Potential release of contaminants stored in harbor sediments through dredging and shipping operations requires that contaminated areas be identified for proper management of the system and protection of wildlife resources. During 1991, Hyalella azteca were exposed in 10-d static-renewal toxicity tests to pore-water and solid-phase sediment samples collected from 26 sites within Savannah Harbor. Pore-water toxicity was more pronounced than that for solidphase sediment. Toxicity and reduced leaf consumption demonstrated impaired sediment quality at specific sites within Savannah Harbor and Back River. Factors responsible for the decreased sediment quality were ammonia, alkalinity, and metal concentrations (cadmium, chromium, lead, molybdenum, and nickel). Elevated concentrations of metals and toxicities in Back River sediments indicated impacts from adjacent dredge-spoil areas.

Flood Plain Lakes Along the Elbe River - a Forgotten Risk

NASA Astrophysics Data System (ADS)

Heise, Susanne

2014-05-01

Flood Plain Lakes Along the Elbe River - a Forgotten Risk Introduction: Along the German part of the Elbe River, more than 1000 "side structures" form potential sinks of contaminated sediment. They are mostly remains of previous river courses which have been cut off by natural causes or anthropogenic alterations of the river (oxbow lakes), or are floodplain lakes that were formed during high water conditions. These water bodies sometimes have a small opening towards the Elbe, or are hydrodynamically connected only in situations of high discharges. High discharges in the Elbe River, however, are mainly responsible for transporting historic contaminants along with suspended matter from former historic sources in the middle Elbe downstream. As these may settle when the current dies down at the end of a high discharge period, side structures have been under suspicion to have accumulated contaminated material over the last decades. Until this study was conducted, nothing was known about erodibility and contamination of sediment in these lakes even though they could have a large impact on the Elbe River itself: A preliminary investigation showed that the total surface of side structures in the Elbe floodplain adds up to about 50 km2. In case that deposited sediment is contaminated and only the upper 20 cm are prone to resuspension and transport during flooding, 10 Mio m3 of contaminated sediment could potentially be added to the contaminant load during a high water event. This study was carried out to evaluate the risk from these side structures for the environmental quality of the Elbe River. Methods: 15 side structures were investigated. Sediment cores were taken on 1 to 3 locations per water body in order to obtain the following information: • Depth of sediment layer • Erodibility of surface sediment, measured immediately after sampling - using the "Gust Microcosm", • Eroded mass at over-critical shear stress, measured in the lab by eroding a sediment core for one hour and collecting the suspended sediment matter. • Chemical contamination • Ecotoxicological effects Results and Discussion All side structures that were sampled exceeded the national quality guidelines for sediments which have been set by the International Commission for the Protection of the Elbe. In some cases very high concentrations were reached such as 1300 µg/kg dw for p,p-DDD, up to 61 mg/kg for Hg and 39 mg/kg for Cd. Erodibility varied a lot with critical shear stresses of less than 1 cm/s to more than 2 cm/s. Ecotoxicological data were also very different between side structures and sampling locations, but partly indicating very high inhibitions. Methanol extracts of sediments on all locations were screened using the luminescence bacteria test with Vibrio fischeri. Selected sediemt samples were tested applying the sediment contact test with Arthrobacter globiformes and the algae growth inhibition test with Pseudokirchneriella subcapitata. An integrated evaluation of all information led to a classification of 7 sites out of 15 to be of high risk, 7 to be of medium risk and only one site to be of low risk for the environmental quality of the Elbe River.

Wood and Sediment Dynamics in River Corridors

NASA Astrophysics Data System (ADS)

Wohl, E.; Scott, D.

2015-12-01

Large wood along rivers influences entrainment, transport, and storage of mineral sediment and particulate organic matter. We review how wood alters sediment dynamics and explore patterns among volumes of instream wood, sediment storage, and residual pools for dispersed pieces of wood, logjams, and beaver dams. We hypothesized that: volume of sediment per unit area of channel stored in association with wood is inversely proportional to drainage area; the form of sediment storage changes downstream; sediment storage correlates most strongly with wood load; and volume of sediment stored behind beaver dams correlates with pond area. Lack of data from larger drainage areas limits tests of these hypotheses, but analyses suggest a negative correlation between sediment volume and drainage area and a positive correlation between wood and sediment volume. The form of sediment storage in relation to wood changes downstream, with wedges of sediment upstream from jammed steps most prevalent in small, steep channels and more dispersed sediment storage in lower gradient channels. Use of a published relation between sediment volume, channel width, and gradient predicted about half of the variation in sediment stored upstream from jammed steps. Sediment volume correlates well with beaver pond area. Historically more abundant instream wood and beaver populations likely equated to greater sediment storage within river corridors. This review of the existing literature on wood and sediment dynamics highlights the lack of studies on larger rivers.

Prediction of Suspended Sediment in Rivers Using Artificial Neural Networks: Implications for Development of Sediment Budgets

NASA Astrophysics Data System (ADS)

Hamshaw, S. D.; Underwood, K.; Rizzo, D.; Wemple, B. C.; Dewoolkar, M.

2013-12-01

Over 1,000 river miles in Vermont are either impaired or stressed by excessive sedimentation. The higher streamflows and incised river channels have resulted in increased bed and bank erosion. As the climate in Vermont is expected to feature greater and more frequent precipitation events and winter rainfall, the potential for increased sediment loading from erosion processes in the watershed and along the channel are high and a major concern for water resource managers. Typical sediment monitoring comprises periodic sampling during storm events and is often limited to gauged streams with flow data. Continuous turbidity monitoring enhances our understanding of river dynamics by offering high-resolution, temporal measurements to better quantify the total sediment loading occurring during and between storm events. Artificial neural networks, that mimic learning patterns of the human brain, have been effective at predicting flow in small, ungauged rivers using local climate data. This study advances this technology by using an ANN algorithm known as a counter-propagation neural network (CPNN) to predict discharge and suspended sediment in small streams. The first distributed network of continuous turbidity sensors (DTS-12) was deployed in Vermont in the Mad River Watershed, located in Central Vermont. The Mad River and five tributaries were selected as a test bed because seven years of periodic turbidity sampling data are available, it represents a range of watershed characteristics, and because the watershed is also being used for hydrologic model development using the Distributed-Hydrology-Soils-Vegetation Model (DHSVM). Comparison with the DHSVM simulations will allow estimation of the most-likely sources of sediment from the entire watershed and individual subwatersheds. In addition, recent field studies have commenced the quantification of erosion occurring from unpaved roads and streambanks in the same watershed. Periodic water quality sampling during storm events enabled turbidity versus TSS relationships to be established. Sub-watersheds with monitored turbidity and stage also have 15-minute precipitation, soil moisture and air and water temperature data being collected. Stage sensors and theoretical rating curves developed using HEC-RAS and calibrated with discharge measurements are used to validate the flow predictions from the CPNN. The real-time turbidity data are used to train and test the suspended sediment predictions from the CPNN network at each site. The turbidity data are also used to train the CPNN on a subset of tributaries and test on the remaining subwatersheds. Reasonable estimates of suspended sediment discharged from the tributaries and the main stem of the Mad River are calculated and compared enabling a more accurate foundation for building a sediment budget. Results of this study will assist managers in prioritizing mitigation projects to reduce impacts of sediment loading.

Use of surrogate technologies to estimate suspended sediment in the Clearwater River, Idaho, and Snake River, Washington, 2008-10

USGS Publications Warehouse

Wood, Molly S.; Teasdale, Gregg N.

2013-01-01

Elevated levels of fluvial sediment can reduce the biological productivity of aquatic systems, impair freshwater quality, decrease reservoir storage capacity, and decrease the capacity of hydraulic structures. The need to measure fluvial sediment has led to the development of sediment surrogate technologies, particularly in locations where streamflow alone is not a good estimator of sediment load because of regulated flow, load hysteresis, episodic sediment sources, and non-equilibrium sediment transport. An effective surrogate technology is low maintenance and sturdy over a range of hydrologic conditions, and measured variables can be modeled to estimate suspended-sediment concentration (SSC), load, and duration of elevated levels on a real-time basis. Among the most promising techniques is the measurement of acoustic backscatter strength using acoustic Doppler velocity meters (ADVMs) deployed in rivers. The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, Walla Walla District, evaluated the use of acoustic backscatter, turbidity, laser diffraction, and streamflow as surrogates for estimating real-time SSC and loads in the Clearwater and Snake Rivers, which adjoin in Lewiston, Idaho, and flow into Lower Granite Reservoir. The study was conducted from May 2008 to September 2010 and is part of the U.S. Army Corps of Engineers Lower Snake River Programmatic Sediment Management Plan to identify and manage sediment sources in basins draining into lower Snake River reservoirs. Commercially available acoustic instruments have shown great promise in sediment surrogate studies because they require little maintenance and measure profiles of the surrogate parameter across a sampling volume rather than at a single point. The strength of acoustic backscatter theoretically increases as more particles are suspended in the water to reflect the acoustic pulse emitted by the ADVM. ADVMs of different frequencies (0.5, 1.5, and 3 Megahertz) were tested to target various sediment grain sizes. Laser diffraction and turbidity also were tested as surrogate technologies. Models between SSC and surrogate variables were developed using ordinary least-squares regression. Acoustic backscatter using the high frequency ADVM at each site was the best predictor of sediment, explaining 93 and 92 percent of the variability in SSC and matching sediment sample data within +8.6 and +10 percent, on average, at the Clearwater River and Snake River study sites, respectively. Additional surrogate models were developed to estimate sand and fines fractions of suspended sediment based on acoustic backscatter. Acoustic backscatter generally appears to be a better estimator of suspended sediment concentration and load over short (storm event and monthly) and long (annual) time scales than transport curves derived solely from the regression of conventional sediment measurements and streamflow. Changing grain sizes, the presence of organic matter, and aggregation of sediments in the river likely introduce some variability in the model between acoustic backscatter and SSC.

Ecotoxicological bioassays of sediment leachates in a river bed flanked by decommissioned pesticide plants in Nantong City, East China.

PubMed

Zhou, Yan; Wang, Fenghe; Wan, Jinzhong; He, Jian; Li, Qun; Qiang Chen; Gao, Jay; Lin, Yusuo; Zhang, Shengtian

2017-03-01

Traditionally, the toxicity of river contaminants is analyzed chemically or physically through river bed sediments. The biotoxicity of polluted sediment leachates has not caught our attention. This study aims to overcome this deficiency through a battery of biotests which were conducted to monitor comprehensive toxicity of sediment leachates for the Yaogang River in East Jiangsu Province of China, which is in close proximity to former pesticide plants. The general physical and chemical parameters of major pollutants were analyzed from river bed sediments collected at five strategic locations. The ecotoxicity analyses undertaken include overall fish (adult zebrafish) acute toxicity, luminescent bacteria (Vibrio fischeri) bioassay, and zebrafish embryo toxicity assay. Compared with the control group, sediment leachates increased the lethality, inhibited the embryos hatching and induced development abnormalities of zebrafish embryos, and inhibited the luminescence of V. fischeri. The results show that sediment leachates may assume various toxic effects, depending on the test organism. This diverse toxicity to aquatic organisms reflects their different sensitivity to sediment leachates. It is found clearly that V. fischeri was the organism which was characterized by the highest sensitivity to the sediment leachates. The complicated toxicity of leachates was not caused by one single factor but by multiple pollutants together. This indicates the need of estimations of sediment leachate not only taking into account chemical detection but also of applying the biotests to the problem. Thus, multigroup bioassays are necessary to realistically evaluate river ecological risks imposed by leachates.

CROSS-INDUCTION OF PYRENE AND PHENANTHRENE IN MYCOBACTERIUM SP. ISOLATED FROM POLYCYCLIC AROMATIC HYDROCARBON CONTAMINATED RIVER SEDIMENTS

EPA Science Inventory

A polycyclic aromatic hydrocarbon (PAH)-degrading culture enriched from contaminated river sediments and a Mycobacterium sp. isolated from the enrichment were tested to investigate the possible synergistic and antagonistic interactions affecting the degradation of pyrene in the p...

Seasonal Variations in Water-Quality, Antibiotic Residues, Resistant Bacteria and Antibiotic Resistance Genes of Escherichia coli Isolates from Water and Sediments of the Kshipra River in Central India.

PubMed

Diwan, Vishal; Hanna, Nada; Purohit, Manju; Chandran, Salesh; Riggi, Emilia; Parashar, Vivek; Tamhankar, Ashok J; Stålsby Lundborg, Cecilia

2018-06-17

To characterize the seasonal variation, over one year, in water-quality, antibiotic residue levels, antibiotic resistance genes and antibiotic resistance in Escherichia coli isolates from water and sediment of the Kshipra River in Central India. Water and sediment samples were collected from seven selected points from the Kshipra River in the Indian city of Ujjain in the summer, rainy season, autumn and winter seasons in 2014. Water quality parameters (physical, chemical and microbiological) were analyzed using standard methods. High-performance liquid chromatography⁻tandem mass spectrometry was used to determine the concentrations of antibiotic residues. In river water and sediment samples, antibiotic resistance and multidrug resistance patterns of isolated E. coli to 17 antibiotics were tested and genes coding for resistance and phylogenetic groups were detected using multiplex polymerase chain reaction. One-way analysis of variance (ANOVA) and Fisher tests were applied to determine seasonal variation. In river water, seasonal variation was significantly associated with various water quality parameters, presence of sulfamethoxazole residues, bacteria resistant to ampicillin, cefepime, meropenem, amikacin, gentamicin, tigecycline, multidrug resistance and CTX-M-1 gene. The majority of the Extended Spectrum Beta-Lactamase (ESBL)-producing E. coli isolates from river water and sediment in all different seasons belonged to phylogenetic group A or B1. Antibiotic pollution, resistance and resistance genes in the Kshipra River showed significant seasonal variation. Guidelines and regulatory standards are needed to control environmental dissemination of these “pollutants” in this holy river.

Changing trends of rainfall and sediment fluxes in the Kinta River catchment, Malaysia

NASA Astrophysics Data System (ADS)

Ismail, W. R.; Hashim, M.

2015-03-01

The Kinta River, draining an area of 2566 km2, originates in the Korbu Mountain in Perak, Malaysia, and flows through heterogeneous, mixed land uses ranging from extensive forests to mining, rubber and oil palm plantations, and urban development. A land use change analysis of the Kinta River catchment was carried out together with assessment of the long-term trend in rainfall and sediment fluxes. The Mann-Kendall test was used to examine and assess the long-term trends in rainfall and its relationship with the sediment discharge trend. The land use analysis shows that forests, water bodies and mining land declined whilst built and agricultural land use increased significantly. This has influenced the sediment flux of the catchment. However, most of the rainfall stations and river gauging stations are experiencing an increasing trends, except at Kinta river at Tg. Rambutan. Sediment flux shows a net erosion for the period from 1961 to 1969. The total annual sediment discharge in the Kinta River catchment was low with an average rate of 1,757 t/km2/year. From 1970 to 1985, the annual sediment yield rose to an average rate of 4062 t/km2/year. Afterwards, from 1986 to 1993, the total annual sediment discharge decreased to an average rate of 1,306 t/km2/year and increased back during the period 1994 to 2000 to 2109 t/km2/year. From 2001 to 2006 the average sediment flux rate declined to 865 t/km2/year. The decline was almost 80% from the 1970s. High sediment flux in the early 1970s is partly associated with reduced tin mining activities in the area. This decreasing trend in sediment delivery leaving the Kinta River catchment is expected to continue dropping in the future.

Trace metals and persistent organic pollutants in sediments from river-reservoir systems in Democratic Republic of Congo (DRC): Spatial distribution and potential ecotoxicological effects.

PubMed

Mwanamoki, Paola M; Devarajan, Naresh; Thevenon, Florian; Birane, Niane; de Alencastro, Luiz Felippe; Grandjean, Dominique; Mpiana, Pius T; Prabakar, Kandasamy; Mubedi, Josué I; Kabele, Christophe G; Wildi, Walter; Poté, John

2014-09-01

This paper discusses the occurrence and spatial distribution of metals and persistent organic pollutants (POPs: including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), Polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) in sediments from a river-reservoir system. Surface sediments were sampled from thirteen sites of the Congo River Basin and Lake Ma Vallée, both situated in the vicinity of the capital city Kinshasa (Congo Democratic Republic). Sediment qualities were evaluated using toxicity test based on exposing Ostracods to the sediment samples. The highest metal concentrations were observed in sediments subjected to anthropogenic influences, urban runoff and domestic and industrial wastewaters, discharge into the Congo River basin. Ostracods exposed to the sediments resulted in 100% mortality rates after 6d of incubation, indicating the ultimate toxicity of these sediments as well as potential environmental risks. The POPs and PAHs levels in all sediment samples were low, with maximum concentration found in the sediments (area of pool Malebo): OCP value ranged from 0.02 to 2.50 with ∑OCPs: 3.3μgkg(-1); PCB ranged from 0.07 to 0.99 with Total PCBs (∑7×4.3): 15.31μgkg(-1); PAH value ranged from 0.12 to 9.39 with ∑PAHs: 63.89μgkg(-1). Our results indicate that the deterioration of urban river-reservoir water quality result mainly from urban stormwater runoff, untreated industrial effluents which discharge into the river-reservoirs, human activities and uncontrolled urbanization. This study represents useful tools incorporated to evaluate sediment quality in river-reservoir systems which can be applied to similar aquatic environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Geochemical characteristics of Heavy metals of river sediment from the main rivers at Texas, USA.

NASA Astrophysics Data System (ADS)

Matsumoto, I.; Hoffman, D.; MacAlister, J.; Ishiga, H.

2008-12-01

Trinity River is one of the biggest rivers which flows through Dallas and Fort Worth two big cities of USA and are highly populated. Trinity river drains into the Gulf of Mexico. Sediment samples collected from various points along the upper and lower streams were subjected to content analysis and elution analysis (using liquate (flow) out test) on the heavy metals like Cd, CN, Pb, Cr, As, Hg, Ni, Zn and Cu from the river sediment for the purpose of environment assessment. A total of 22 sample points were identified from upper stream to lower stream and samples were collected such that almost the whole stream length of Trinity River is covered. Results show that heavy metal content through out the river stream is below the recommended limits posing no immediate environmental threat. However, the experimental results show clear impact of human population in bigger cities on heavy metal concentrations in the river sediments as compared to smaller cities with low human population. It could be seen from the analysis that all the heavy metals show relatively high content and high elution value in Dallas and Fort Worth. As we move away from the big cities, the value of content and elution of sediment decreased by natural dilution effect by the river. And we also present the data of the Colorado and San Antonio rivers.

Deposition and flux of sediment from the Po River, Italy: An idealized and wintertime numerical modeling study

USGS Publications Warehouse

Bever, A.J.; Harris, C.K.; Sherwood, C.R.; Signell, R.P.

2009-01-01

Recent studies of sediment dynamics and clinoform development in the northern Adriatic Sea focused on winter 2002-2003 and provided the data and motivation for development of a detailed sediment-transport model for the area near the Po River delta. We used both idealized test cases and more realistic simulations to improve our understanding of seasonal sediment dynamics there. We also investigated the relationship between physical processes and the observed depositional products; e.g. the accumulation of sediment very near the Po River distributary mouths. Sediment transport near the Po River was evaluated using a three-dimensional ocean model coupled to sediment-transport calculations that included wave- and current-induced resuspension, suspended-sediment transport, multiple grain classes, and fluvial input from the Po River. High-resolution estimates from available meteorological and wave models were used to specify wind, wave, and meteorological forcing. Model results indicated that more than half of the discharged sediment remained within 15??km of the Po River distributary mouths, even after two months of intensive reworking by winter storms. During floods of the Po River, transport in the middle to upper water column dominated sediment fluxes. Otherwise, sediment fluxes from the subaqueous portion of the delta were confined to the bottom few meters of the water column, and correlated with increases in current speed and wave energy. Spatial and temporal variation in wind velocities determined depositional patterns and the directions of sediment transport. Northeasterly Bora winds produced relatively more eastward transport, while southwesterly Sirocco winds generated fluxes towards both the north and the south. Eastward transport accounted for the majority of the sediment exported from the subaqueous delta, most likely due to the frequent occurrence of Bora conditions. Progradation of the Po River delta into the Adriatic Sea may restrict the formation of the Western Adriatic Coastal Current, increasing sediment retention at the Po delta and reducing the supply of sediment to the Apennine margin. A positive morphodynamic feedback may therefore be present whereby the extension of the delta into the Adriatic increases sediment accumulation at the delta and facilitates further progradation. ?? 2009 Elsevier B.V.

Assessing contamination in Great Lakes sediments using benthic invertebrate communities and the sediment quality triad approach

USGS Publications Warehouse

Canfield, Timothy J.; Dwyer, F. James; Fairchild, James F.; Haverland, Pamela S.; Ingersoll, Christopher G.; Kemble, Nile E.; Mount, David R.; La Point, Thomas W.; Burton, G. Allen; Swift, M. C.

1996-01-01

Sediments in many Great Lakes harbors and tributary rivers are contaminated. As part of the USEPA's Assessment and Remediation of Contaminated Sediment (ARCS) program, a number of studies were conducted to determine the nature and extent of sediment contamination in Great Lakes Areas of Concern (AOC). This paper describes the composition of benthic invertebrate communities in contaminated sediments and is one in a series of papers describing studies conducted to evaluate sediment toxicity from three AOC's (Buffalo River, NY; Indiana Harbor, IN; Saginaw River, MI), as part of the ARCS Program. Oligochaeta (worms) and Chironomidae (midge) comprised over 90% of the benthic invertebrate numbers in samples collected from depositional areas. Worms and midge consisted of taxa identified as primarily contaminant tolerant organisms. Structural deformities of mouthparts in midge larvae were pronounced in many of the samples. Good concurrence was evident between measures of laboratory toxicity, sediment contaminant concentration, and benthic invertebrate community composition in extremely contaminated samples. However, in moderately contaminated samples, less concordance was observed between the benthos community composition and either laboratory toxicity test results or sediment contaminant concentration. Laboratory sediment toxicity tests may better identify chemical contamination in sediments than many commonly used measures of benthic invertebrate community composition. Benthic measures may also reflect other factors such as habitat alteration. Evaluation of non-contaminant factors are needed to better interpret the response of benthic invertebrates to sediment contamination.

Background Radioactivity in River and Reservoir Sediments near Los Alamos, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.G.McLin; D.W. Lyons

2002-05-05

As part of its continuing Environmental Surveillance Program, regional river and lake-bottom sediments have been collected annually by Los Alamos National Laboratory (the Laboratory) since 1974 and 1979, respectively. These background samples are collected from three drainage basins at ten different river stations and five reservoirs located throughout northern New Mexico and southern Colorado. Radiochemical analyses for these sediments include tritium, strontium-90, cesium-137, total uranium, plutonium-238, plutonium-239,-240, americium-241, gross alpha, gross beta, and gross gamma radioactivity. Detection-limit radioactivity originates as worldwide fallout from aboveground nuclear weapons testing and satellite reentry into Earth's atmosphere. Spatial and temporal variations in individual analytemore » levels originate from atmospheric point-source introductions and natural rate differences in airborne deposition and soil erosion. Background radioactivity values on sediments reflect this variability, and grouped river and reservoir sediment samples show a range of statistical distributions that appear to be analyte dependent. Traditionally, both river and reservoir analyte data were blended together to establish background levels. In this report, however, we group background sediment data according to two criteria. These include sediment source (either river or reservoir sediments) and station location relative to the Laboratory (either upstream or downstream). These grouped data are statistically evaluated through 1997, and background radioactivity values are established for individual analytes in upstream river and reservoir sediments. This information may be used to establish the existence and areal extent of trace-level environmental contamination resulting from historical Laboratory research activities since the early 1940s.« less

Evaluation of PCB bioaccumulation by Lumbriculus variegatus in field-collected sediments

EPA Science Inventory

Sediment bioaccumulation tests with Lumbriculus variegatus were performed on polychlorinated biphenyl (PCBs) contaminated sediment samples from the Hudson, Grasse, and Fox Rivers Superfund sites with concurrent measurement of PCB concentrations in sediment interstitial water. Th...

Testing laser-based sensors for continuous in situ monitoring of suspended sediment in the Colorado River, Arizona

USGS Publications Warehouse

Melis, T.S.; Topping, D.J.; Rubin, D.M.; Bogen, J.; Fergus, T.; Walling, D.

2003-01-01

High-resolution monitoring of sand mass balance in the Colorado River below Glen Canyon Dam, Arizona, USA, is needed for environmental management. In the Grand Canyon, frequent collection of suspended-sediment samples from cableways is logistically complicated, costly and provides limited spatial and temporal resolution. In situ laser sensors were tested in the Colorado River as an alternative method for monitoring the river's suspended transport. LISST data were collected at a fixed-depth, near-shore site while isokinetic measurements were simultaneously made from a nearby cableway. Diurnal variations in LISST grain size and concentration data compared well with depth-integrated, cross-section data. Tbe LISST was also successfully used to electronically trigger an ISCO 6712 pump sampler to provide continuous monitoring during periods when suspended concentrations exceeded the LISST's measurement range. Initial results indicate that the LISST can provide useful high-resolution suspended-sediment data within the Colorado River, when optics are maintained on a weekly basis.

A Pilot-scale Benthic Microbial Electrochemical System (BMES) for Enhanced Organic Removal in Sediment Restoration

NASA Astrophysics Data System (ADS)

Li, Henan; Tian, Yan; Qu, Youpeng; Qiu, Ye; Liu, Jia; Feng, Yujie

2017-01-01

A benthic microbial electrochemical systems (BMES) of 195 L (120 cm long, 25 cm wide and 65 cm height) was constructed for sediment organic removal. Sediment from a natural river (Ashi River) was used as test sediments in the present research. Three-dimensional anode (Tri-DSA) with honeycomb structure composed of carbon cloth and supporting skeleton was employed in this research for the first time. The results demonstrated that BMES performed good in organic-matter degradation and energy generation from sediment and could be considered for river sediments in situ restoration as novel method. Community analysis from the soil and anode using 16S rDNA gene sequencing showed that more electrogenic functional bacteria was accumulated in anode area when circuit connected than control system.

Influence of Aroclor 1242 concentration on polychlorinated biphenyl biotransformations in Hudson River test tube microcosms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fish, K.M.

1996-08-01

PCBs are a family of compounds sold with various levels of chlorination and under different trade names. They have accumulated in soils, sediments, and biota, raising concerns about possible health risks. The upper Hudson River was contaminated with Aroclor 1242. This study examines the influence of Aroclor concentration on PCB biotransformations in the upper Hudson River sediment. 6 refs., 3 figs.

Reconstructing Sediment Supply, Transport and Deposition Behind the Elwha River Dams

NASA Astrophysics Data System (ADS)

Beveridge, C.

2017-12-01

The Elwha River watershed in Olympic National Park of Washington State, USA is predominantly a steep, mountainous landscape where dominant geomorphic processes include landslides, debris flows and gullying. The river is characterized by substantial variability of channel morphology and fluvial processes, and alternates between narrow bedrock canyons and wider alluvial reaches for much of its length. Literature suggests that the Elwha watershed is topographically and tectonically in steady state. The removal of the two massive hydropower dams along the river in 2013 marked the largest dam removal in history. Over the century long lifespan of the dams, approximately 21 million cubic meters of sediment was impounded behind them. Long term erosion rates documented in this region and reservoir sedimentation data give unprecedented opportunities to test watershed sediment yield models and examine dominant processes that control sediment yield over human time scales. In this study, we aim to reconstruct sediment supply, transport and deposition behind the Glines Canyon Dam (most upstream dam) over its lifespan using a watershed modeling approach. We developed alternative models of varying complexity for sediment production and transport at the network scale driven by hydrologic forcing. We simulate sediment supply and transport in tributaries upstream of the dam. The modeled sediment supply and transport dynamics are based on calibrated formulae (e.g., bedload transport is simulated using Wilcock-Crowe 2003 with modification based on observed bedload transport in the Elwha River). Observational data that aid in our approach include DEM, channel morphology, meteorology, and streamflow and sediment (bedload and suspended load) discharge. We aim to demonstrate how the observed sediment yield behind the dams was influenced by upstream transport supply and capacity limitations, thereby demonstrating the scale effects of flow and sediment transport processes in the Elwha River watershed.

Sediment toxicity testing with the amphipod Ampelisca abdita in Calcasieu Estuary, Louisiana

USGS Publications Warehouse

Redmond, M.S.; Crocker, P.A.; McKenna, K.M.; Petrocelli, E.A.; Scott, K.J.; Demas, C.R.

1996-01-01

Discharges from chemical and petrochemical manufacturing facilities have contaminated portions of Louisiana's Calcasieu River estuary with a variety of organic and inorganic contaminants. As part of a special study, sediment toxicity testing was conducted to assess potential impact to the benthic community. Ten-day flow-through sediment toxicity tests with the amphipod Ampelisca abdita revealed significant toxicity at 68% (26 of 38) of the stations tested. A. abdita mortality was highest in the effluent-dominated bayous, which are tributaries to the Calcasieu River. Mortality was correlated with total heavy metal and total organic compound concentrations in the sediments. Ancillary experiments showed that sediment interstitial water salinity as low as 2.5 o/o-o did not significantly affect A. abdita's, response in the flow-through system; sediment storage for 7 weeks at 4??C did not significantly affect toxicity. Sediment toxicity to A. abdita was more prevalent than receiving water toxicity using three short-term chronic bioassays. Results suggest that toxicity testing using this amphipod is a valuable tool when assessing sediments containing complex contaminant mixtures and for assessing effects of pollutant loading over time. In conjunction with chemical analyses, the testing indicated that the effluent-dominated, brackish bayous (Bayou d'Inde and Bayou Verdine) were the portions of the estuary most impacted by toxicity.

Assessment of pathogen levels in stream water column and bed sediment of Merced River Watershed in California

NASA Astrophysics Data System (ADS)

Vaddella, V. K.; Pandey, P.; Biswas, S.; Lewis, D. J.

2014-12-01

Mitigating pathogen levels in surface water is crucial for protecting public health. According to the U.S. Environmental Protection Agency (US EPA), approximately 480,000 km of rivers/streams are contaminated in the U.S., and a major cause of contamination is elevated levels of pathogen/pathogen indicator. Many of past studies showed considerably higher pathogen levels in sediment bed than that of the stream water column in rivers. In order to improve the understanding of pathogen levels in rivers in California, we carried out an extensive pathogen monitoring study in four different watersheds (Bear Creek, Ingalsbe, Maxwell, and Yosemite watersheds) of Merced River. Stream water and streambed sediment samples were collected from 17 locations. Pathogen levels (E. coli O157:H7, Salmonella spp., and Listeria monocytogenes) were enumerated in streambed sediment and water column. In addition, the impacts of heat stress on pathogen survival were assessed by inoculating pathogens into the water and sediment samples for understanding the pathogen survival in stream water column and streambed sediment. The pathogen enumeration (in water column and sediment bed) results indicated that the E. coli O157:H7, Salmonella spp. and Listeria monocytogenes levels were non-detectable in the water column and streambed sediment. The results of heat stress (50◦ C for 180 minutes) test indicated a pathogen decay at one order of magnitude (108 cfu/ml to 107 cfu/ml). Nonetheless, higher pathogen levels (1.13 × 107 cfu/ml) after the heat stress study showed potential pathogen survival at higher temperature. Preliminary results of this study would help in understanding the impacts of elevated temperature on pathogen in stream environment. Further studies are required to test the long-term heat-stress impacts on pathogen survival.

Comparison. US P-61 and Delft sediment samplers

USGS Publications Warehouse

Beverage, Joseph P.; Williams, David T.

1990-01-01

The Delft Bottle (DB) is a flow-through device designed by the Delft Hydraulic Laboratory (DHL), The Netherlands, to sample sand-sized sediment suspended in streams. The US P-61 sampler was designed by the Federal Interagency Sedimentation Project (FISP) at the St. Anthony Falls Hydraulic Laboratory, Minneapolis, Minnesota, to collect suspended sediment from deep, swift rivers. The results of two point-sampling tests in the United States, the Mississippi River near Vicksburg, Mississippi, in 1983 and the Colorado River near Blythe, California, in 1984, are provided in this report. These studies compare sand-transport rates, rather than total sediment-transport rates, because fine material washes through the DB sampler. In the United States, the commonly used limits for sand-sized material are 0.062 mm to 2.00 mm (Vanoni 1975).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

Toxicity testing of split whole sediment samples using juvenile freshwater mussels (Anodonta imbecillis) was conducted by TVA to provide a quality assurance mechanism for test organism quality and overall performance of the test being conducted by CR-ERP personnel as part of the CR-ERP biomonitoring study of Clinch River sediments. Testing of sediment samples collected September 8 from Poplar Creek Miles 6.0 and 1.0 was conducted September 13-22, 1994. Results from this test showed no toxicity (survival effects) to fresh-water mussels during a 9-day exposure to the sediments.

Integrated assessment of contaminated sediments in the lower Fox River and Green Bay, Wisconsin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ankley, G.T.; Lodge, K.; Call, D.J.

Samples of sediment and biota were collected from sites in the lower Fox River and southern Green Bay to determine existing or potential impacts of sediment-associated contaminants on different ecosystem components of this Great Lakes area of concern. Evaluation of benthos revealed a relatively depauperate community, particularly at the lower Fox River sites. Sediment pore water and bulk sediments from several lower Fox River sites were toxic to a number of test species including Pimephales promelas, Ceriodaphnia dubia, Hexagenia limbata, Selenastrum capricornutum, and Photobacterium phosphorum. An important component of the observed toxicity appeared to be due to ammonia. Evaluation ofmore » three bullhead (Ictalurus) species from the lower Fox River revealed an absence of preneoplastic or neoplastic liver lesions, and the Salmonella typhimurium bioassay indicated relatively little mutagenicity in sediment extracts. Apparent adverse reproductive effects were noted in two species of birds nesting along the lower Fox River and on a confined disposal facility for sediments near the mouth of the river, and there were measurable concentrations of potentially toxic 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), and planar polychlorinated biphenyls (PCBs) both in the birds and in sediments from several of the study sites. Based on toxic equivalency factors and the results of an in vitro bioassay with H4IIE rat hepatoma cells, it appeared that the majority of potential toxicity of the PCB/PCDF/PCDD mixture in biota from the lower Fox River/Green Bay system was due to the planar PCBs. The results of these studies are discussed in terms of an integrated assessment focused on providing data for remedial action planning.« less

Assessing natural and anthropogenic influences on water discharge and sediment load in the Yangtze River, China.

PubMed

Zhao, Yifei; Zou, Xinqing; Liu, Qing; Yao, Yulong; Li, Yali; Wu, Xiaowei; Wang, Chenglong; Yu, Wenwen; Wang, Teng

2017-12-31

The water discharge and sediment load of rivers are changing substantially under the impacts of climate change and human activities, becoming a hot issue in hydro-environmental research. In this study, the water discharge and sediment load in the mainstream and seven tributaries of the Yangtze River were investigated by using long-term hydro-meteorological data from 1953 to 2013. The non-parametric Mann-Kendall test and double mass curve (DMC) were used to detect trends and abrupt change-points in water discharge and sediment load and to quantify the effects of climate change and human activities on water discharge and sediment load. The results are as follows: (1) the water discharge showed a non-significant decreasing trend at most stations except Hukou station. Among these, water discharge at Dongting Lake and the Min River basin shows a significant decreasing trend with average rates of -13.93×10 8 m 3 /year and -1.8×10 8 m 3 /year (P<0.05), respectively. However, the sediment load exhibited a significant decreasing trend in all tributaries of the Yangtze River. (2) No significant abrupt change-points were detected in the time series of water discharge for all hydrological stations. In contrast, significant abrupt change-points were detected in sediment load, most of these changes appeared in the late 1980s. (3) The water discharge was mainly influenced by precipitation in the Yangtze River basin, whereas sediment load was mainly affected by climate change and human activities; the relative contribution ratios of human activities were above 70% for the Yangtze River. (4) The decrease of sediment load has directly impacted the lower Yangtze River and the delta region. These results will provide a reference for better resource management in the Yangtze River Basin. Copyright © 2017 Elsevier B.V. All rights reserved.

Recent (1995-1998) Canadian research on contemporary processes of river erosion and sedimentation, and river mechanics

NASA Astrophysics Data System (ADS)

Ashmore, P.; Conly, F. M.; Deboer, D.; Martin, Y.; Petticrew, E.; Roy, A.

2000-06-01

Canadian research on contemporary erosion and sedimentation processes covers a wide range of scales, processes, approaches and environmental problems. This review of recent research focuses on the themes of sediment yield, land-use impact, fine-sediment transport, bed material transport and river morphology and numerical modelling of fluvial landscape development.Research on sediment yield and denudation has confirmed that Canadian rivers are often dominated by riparian sediment sources. Studies of the effects of forestry on erosion, in-stream sedimentation and habitat are prominent, including major field experimental studies in coastal and central British Columbia. Studies of fine-sediment transport mechanisms have focused on the composition of particles and the dynamics of flocculation. In fluvial dynamics there have been important contributions to problems of turbulence-scale flow structure and entrainment processes, and the characteristics of bedload transport in gravel-bed rivers. Although much of the work has been empirical and field-based, results of numerical modelling of denudational processes and landscape development also have begun to appear.The nature of research in Canada is driven by the progress of the science internationally, but also by the nature of the Canadian landscape, its history and resource exploitation. Yet knowledge of Canadian rivers is still limited, and problems of, for example, large pristine rivers or rivers in cold climates, remain unexplored. Research on larger scale issues of sediment transfer or the effects of hydrological change is now hampered by reductions in national monitoring programmes. This also will make it difficult to test theory and assess modelling results. Monitoring has been replaced by project- and issues-based research, which has yielded some valuable information on river system processes and opened opportunities for fluvial scientists. However, future contributions will depend on our ability to continue with fundamental fluvial science while fulfilling the management agenda.

Concentration and transport of chlordane and nonachlor associated with suspended sediment in the Mississippi River, May 1988 to June 1990

USGS Publications Warehouse

Rostad, C.E.

1997-01-01

Technical chlordane, a formerly widely used organochlorine pesticide, has become widespread in the environment. The distribution of technical chlordane in riverine environments may be due in part to resuspension and aqueous transport of contaminated bed sediment. To test this hypothesis, the Mississippi River was sampled for suspended sediment five times over a two- year period, at up to 17 sites from St. Louis to below New Orleans, including major tributaries. The ratio of chlordane to nonachlor concentrations averaged 3.6 during May-June 1988 for the Mississippi River below its confluence with the Ohio River. During March-April 1989, the ratio was 0.6, suggesting weathered technical chlordane contributions to the suspended sediment. During June 1989, the ratio averaged 1.1, indicating some input of less weathered technical chlordane. During February-March and May-June 1990, the ratios again shifted, from 0.8 to 1.3. This shifting ratio is likely due to resuspension of weathered technical chlordane associated with bed sediment during spring runoff. Annual transport by suspended sediment from the Mississippi River to the Gulf of Mexico was estimated to be 110 kg of chlordane and 100 kg of nonachlor.

Sediment-stabilizing and Destabilizing Ecoengineering Species from River to Estuary: the Case of the Scheldt System

NASA Astrophysics Data System (ADS)

Selakovic, S.; Cozzoli, F.; Leuven, J.; Van Braeckel, A.; Speybroeck, J.; Kleinhans, M. G.; Bouma, T.

2017-12-01

Interactions between organisms and landscape forming processes play an important role in evolution of coastal landscapes. In particular, biota has a strong potential to interact with important geomorphological processes such as sediment dynamics. Although many studies worked towards quantifying the impact of different species groups on sediment dynamics, information has been gathered on an ad hoc base. Depending on species' traits and distribution, functional groups of ecoengineering species may have differential effects on sediment deposition and erosion. We hypothesize that the spatial distributions of sediment-stabilizing and destabilizing species across the channel and along the whole salinity gradient of an estuary partly determine the planform shape and channel-shoal morphology of estuaries. To test this hypothesis, we analyze vegetation and macrobenthic data taking the Scheldt river-estuarine continuum as model ecosystem. We identify species traits with important effects on sediment dynamics and use them to form functional groups. By using linearized mixed modelling, we are able to accurately describe the distributions of the different functional groups. We observe a clear distinction of dominant ecosystem engineering functional groups and their potential effects on the sediment in the river-estuarine continuum. The first results of longitudinal cross section show the highest effects of stabilizing plant species in riverine and sediment bioturbators in weak polyhaline part of continuum. The distribution of functional groups in transverse cross sections shows dominant stabilizing effect in supratidal zone compared to dominant destabilizing effect in the lower intertidal zone. This analysis offers a new and more general conceptualization of distributions of sediment stabilizing and destabilizing functional groups and their potential impacts on sediment dynamics, shoal patterns, and planform shapes in river-estuarine continuum. We intend to test this in future modelling and experiments.

Mycobacterium avium subsp. paratuberculosis in Lake Catchments, in River Water Abstracted for Domestic Use, and in Effluent from Domestic Sewage Treatment Works: Diverse Opportunities for Environmental Cycling and Human Exposure

PubMed Central

Pickup, R. W.; Rhodes, G.; Bull, T. J.; Arnott, S.; Sidi-Boumedine, K.; Hurley, M.; Hermon-Taylor, J.

2006-01-01

Mycobacterium avium subsp. paratuberculosis from infected animals enters surface waters and rivers in runoff from contaminated pastures. We studied the River Tywi in South Wales, United Kingdom, whose catchment comprises 1,100 km2 containing more than a million dairy and beef cattle and more than 1.3 million sheep. The River Tywi is abstracted for the domestic water supply. Between August 2002 and April 2003, 48 of 70 (68.8%) twice-weekly river water samples tested positive by IS900 PCR. In river water, the organisms were associated with a suspended solid which was depleted by the water treatment process. Disposal of contaminated slurry back onto the land established a cycle of environmental persistence. A concentrate from 100 liters of finished water tested negative, but 1 of 54 domestic cold water tanks tested positive, indicating the potential for these pathogens to access domestic outlets. In the separate English Lake District region, with hills up to 980 m, tests for M. avium subsp. paratuberculosis in the high hill lakes and sediments were usually negative, but streams and sediments became positive lower down the catchment. Sediments from 9 of 10 major lakes receiving inflow from these catchments were positive, with sediment cores indicating deposition over at least 40 to 50 years. Two of 12 monthly 1-liter samples of effluent and a single 100-liter sample from the Ambleside sewage treatment works were positive for M. avium subsp. paratuberculosis. Since Lake Ambleside discharges into Lake Windermere, which is available for domestic supply, there is a potential for these organisms to cycle within human populations. PMID:16751517

Assessing condition of macroinvertebrate communities and sediment toxicity in the St. Lawrence River at Massena Area-of-Concern

USGS Publications Warehouse

Duffy, Brian T.; Baldigo, Barry P.; Smith, Alexander J.; George, Scott D.; David, Anthony M.

2016-01-01

In 1972, the USA and Canada agreed to restore the chemical, physical, and biological integrity of the Great Lakes ecosystem under the first Great Lakes Water Quality Agreement. In subsequent amendments, part of the St. Lawrence River at Massena, New York and segments of three tributaries, were designated as an Area of Concern (AOC) due to the effects of polychlorinated biphenyls (PCBs), lead and copper contamination, and habitat degradation and resulting impairment to several beneficial uses. Because sediments have been largely remediated, the present study was initiated to evaluate the current status of the benthic macroinvertebrate (benthos) beneficial use impairment (BUI). Benthic macroinvertebrate communities and sediment toxicity tests using Chironomus dilutus were used to test the hypotheses that community condition and sediment toxicity at AOC sites were not significantly different from those of adjacent reference sites. Grain size was found to be the main driver of community composition and macroinvertebrate assemblages, and bioassessment metrics did not differ significantly between AOC and reference sites of the same sediment class. Median growth of C. dilutus and its survival in three of the four river systems did not differ significantly in sediments from AOC and reference sites. Comparable macroinvertebrate assemblages and general lack of toxicity across most AOC and reference sites suggest that the quality of sediments should not significantly impair benthic macroinvertebrate communities in most sites in the St. Lawrence River AOC.

(210)Pb and compositional data of sediments from Rondonian lakes, Madeira River basin, Brazil.

PubMed

Bonotto, Daniel Marcos; Vergotti, Marcelo

2015-05-01

Gold exploration has been intensive in Brazilian Amazon over the last 40 years, where the use of mercury as an amalgam has caused abnormal Hg concentrations in water bodies. Special attention has been directed to Madeira River due to fact it is a major tributary of Amazon River and that since 1986, gold exploration has been officially permitted along a 350km sector of the river. The (21)(0)Pb method has been used to date sediments taken from nine lakes situated in Madeira River basin, Rondônia State, and to verify where anthropogenic Hg might exist due to gold exploitation in Madeira River. Activity profiles of excess (21)(0)Pb determined in the sediment cores provided a means to evaluate the sedimentation rates using a Constant Flux: Constant Sedimentation (CF:CS) and Constant Rate of Supply (CRS) of unsupported/excess (21)(0)Pb models. A significant relationship was found between the CF:CS sedimentation rates and the mean values of the CRS sedimentation rates (Pearson correlation coefficient r=0.59). Chemical data were also determined in the sediments for identifying possible relationships with Hg occurring in the area. Significant values were found in statistical correlation tests realized among the Hg, major oxides and Total Organic Carbon (TOC) content in the sediments. The TOC increased in the sediment cores accompanied by a loss on ignition (LOI) increment, whereas silica decreased following a specific surface area raising associated to the TOC increase. The CRS model always provided ages within the permitted range of the (21)(0)Pb-method in the studied lakes, whereas the CF:CS model predicted two values above 140 years. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identification of water soluble and particle bound compounds causing sublethal toxic effects. A field study on sediments affected by a chlor-alkali industry.

PubMed

Bosch, Carme; Olivares, Alba; Faria, Melissa; Navas, Jose M; del Olmo, Iván; Grimalt, Joan O; Piña, Benjamín; Barata, Carlos

2009-08-13

A combination of cost effective sublethal Daphnia magna feeding tests, yeast- and cell culture-based bioassays and Toxicity Identification Evaluation (TIE) procedures was used to characterize toxic compounds within sediments collected in a river area under the influence of the effluents from a chlor-alkali industry (Ebro River, NE Spain). Tests were designed to measure and identify toxic compounds in the particulate and filtered water fractions of sediment elutriates. The combined use of bioassays responding to elutriates and dioxin-like compounds evidenced the existence of three major groups of hazardous contaminants in the most contaminated site: (A) metals such as cadmium and mercury bound to sediment fine particles that could be easily resuspended and moved downstream, (B) soluble compounds (presumably, lye) able to alkalinize water to toxic levels, and (C) organochlorine compounds with high dioxin-like activity. These results provided evidence that elutriate D. magna feeding responses can be used as surrogate assays for more tedious chronic whole sediment tests, and that the incorporation of such tests in sediment TIE procedures may improve the ability to identify the toxicity of particle-bound and water-soluble contaminants in sediments.

Wildfire vs. Agricultural Operations: A Tale of Overprinted Disturbance Regimes

NASA Astrophysics Data System (ADS)

Gray, A. B.; Pasternack, G. B.; Watson, E. B.; Warrick, J. A.; Hatten, J. A.; Goni, M. A.

2016-12-01

Punctuated disturbances, such as wildfire, compete with interdecadal scale changes to land surfaces, such as shifting agricultural practices, resulting in complex trends in the suspended sediment transport dynamics of watersheds. A powerful, though data intensive approach to identifying dominant disturbance regimes is the application of retrospective forensic analysis, whereby time series of major factors potentially affecting watershed expression are investigated. In the test case, a decreasing trend in discharge corrected suspended sediment concentrations was found in the lower Salinas River, California between 1967 and 2011. Event to decadal scale patterns in sediment production in the Salinas River have been found to be largely controlled by antecedent hydrologic conditions, but decreasing suspended sediment concentrations over the last 15 years of the record departed from those expected from hydro-climatic forcing. Sediment production from the mountainous headwaters of the central California Coast Ranges, which are drained in part by the Salinas River, is known to be dominated by the interaction of wildfire and large rainfall/runoff events. However, the decreasing trend in Salinas River suspended sediment concentrations run contrary to increases in the watershed's effective burn area over time. The departure from hydrologic and wildfire forcing on suspended sediment concentration patterns was found to coincide with a rapid conversion of irrigation practices from sprinkler and furrow to subsurface drip irrigation. Changes in agricultural operations appear to have decreased sediment supply to the Salinas River over late 20th to early 21st century; obscuring the influence of wildfire on suspended sediment production.

Sources of suspended-sediment loads in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary, south Texas, 1958–2010

USGS Publications Warehouse

Ockerman, Darwin J.; Heitmuller, Franklin T.; Wehmeyer, Loren L.

2013-01-01

During 2010, additional suspended-sediment data were collected during selected runoff events to provide new data for model testing and to help better understand the sources of suspended-sediment loads. The model was updated and used to estimate and compare sediment yields from each of 64 subwatersheds comprising the lower Nueces River watershed study area for three selected runoff events: November 20-21, 2009, September 7-8, 2010, and September 20-21, 2010. These three runoff events were characterized by heavy rainfall centered near the study area and during which minimal streamflow and suspended-sediment load entered the lower Nueces River upstream from Wesley E. Seale Dam. During all three runoff events, model simulations showed that the greatest sediment yields originated from the subwatersheds, which were largely cropland. In particular, the Bayou Creek subwatersheds were major contributors of suspended-sediment load to the lower Nueces River during the selected runoff events. During the November 2009 runoff event, high suspended-sediment concentrations in the Nueces River water withdrawn for the City of Corpus Christi public-water supply caused problems during the water-treatment process, resulting in failure to meet State water-treatment standards for turbidity in drinking water. Model simulations of the November 2009 runoff event showed that the Bayou Creek subwatersheds were the primary source of suspended-sediment loads during that runoff event.

A TOXICITY ASSESSMENT APPROACH FOR THE EVALUATION OF IN-SITU BIOREMEDIATION OF PAH CONTAMINATED SEDIMENTS

EPA Science Inventory

Freshwater and marine sediment toxicity test were used to measure baseline toxicity of sediment samples collected from New York/New Jersey Harbor (NY/NJH) and East River (ER) (PAH contaminated) sediments and to determine the effectiveness of the developed biotreatment strategies ...

River mouth morphodynamics - Examples from small, mountainous rivers (Invited)

NASA Astrophysics Data System (ADS)

Warrick, J. A.

2013-12-01

Small, high-sediment yield rivers are known to discharge massive amounts of sediment to the world's oceans. Because of these high rates of sediment discharge, many of these small rivers provide important sources of sediment to littoral cells, such as those along the west coasts of North and South America. Sediment discharge from these small watersheds is commonly ephemeral and dominated by infrequent high flow. Thus, the morphodynamic states of these river mouths will vary with time, often being 'wave dominated' for the majority of the year and then changing to 'river dominated' during river sediment discharge events. Here I will provide a summary of recent observations of the morphodynamics of river mouths along California that reveal that sediment dispersal and deposition patterns vary owing to the sediment transport processes at the river mouths, which are influenced by the buoyancy of the river discharge. During low rates of sediment discharge and low river sediment concentrations, sediment dispersal will occur in hypopycnal (positively buoyant) plumes and sand deposition will be close to the river mouth. These conditions commonly result in transfer of sand from the river delta to the littoral cell during the first 1-2 years following the river discharge event. During high rates of sediment discharge and high river sediment concentrations, river discharge may form hyperpycnal (negatively buoyant) plumes and disperse sand to deeper portions of the continental shelf, where transfer back to the littoral cell may take decades or may not occur. High-resolution bathymetry from southern California provides several examples of sand dispersal by hyperpycnal plumes to regions of the inner and middle continental shelf. Thus, sediment dispersal from river mouths influences coastal morphodynamics, morphology, and the rates and timing of sediment supply to littoral cells.

Nitrate removal in deep sediments of a nitrogen-rich river network: A test of a conceptual model

USGS Publications Warehouse

Stelzer, Robert S.; Bartsch, Lynn

2012-01-01

Many estimates of nitrogen removal in streams and watersheds do not include or account for nitrate removal in deep sediments, particularly in gaining streams. We developed and tested a conceptual model for nitrate removal in deep sediments in a nitrogen-rich river network. The model predicts that oxic, nitrate-rich groundwater will become depleted in nitrate as groundwater upwelling through sediments encounters a zone that contains buried particulate organic carbon, which promotes redox conditions favorable for nitrate removal. We tested the model at eight sites in upwelling reaches of lotic ecosystems in the Waupaca River Watershed that varied by three orders of magnitude in groundwater nitrate concentration. We measured denitrification potential in sediment core sections to 30 cm and developed vertical nitrate profiles to a depth of about 1 m with peepers and piezometer nests. Denitrification potential was higher, on average, in shallower core sections. However, core sections deeper than 5 cm accounted for 70%, on average, of the depth-integrated denitrification potential. Denitrification potential increased linearly with groundwater nitrate concentration up to 2 mg NO3-N/L but the relationship broke down at higher concentrations (> 5 mg NO3-N/L), a pattern that suggests nitrate saturation. At most sites groundwater nitrate declined from high concentrations at depth to much lower concentrations prior to discharge into the surface water. The profiles suggested that nitrate removal occurred at sediment depths between 20 and 40 cm. Dissolved oxygen concentrations were much higher in deep sediments than in pore water at 5 cm sediment depth at most locations. The substantial denitrification potential in deep sediments coupled with the declines in nitrate and dissolved oxygen concentrations in upwelling groundwater suggest that our conceptual model for nitrate removal in deep sediments is applicable to this river network. Our results suggest that nitrate removal rates can be high in deep sediments of upwelling stream reaches, which may have implications for efforts to understand and quantify nitrogen transport and removal at larger scales.

Fish embryo tests with Danio rerio as a tool to evaluate surface water and sediment quality in rivers influenced by wastewater treatment plants using different treatment technologies.

PubMed

Thellmann, Paul; Köhler, Heinz-R; Rößler, Annette; Scheurer, Marco; Schwarz, Simon; Vogel, Hans-Joachim; Triebskorn, Rita

2015-11-01

In order to evaluate surface water and the sediment quality of rivers connected to wastewater treatment plants (WWTPs) with different treatment technologies, fish embryo tests (FET) with Danio rerio were conducted using native water and sediment samples collected upstream and downstream of four WWTPs in Southern Germany. Two of these WWTPs are connected to the Schussen River, a tributary of Lake Constance, and use a sand filter with final water purification by flocculation. The two others are located on the rivers Schmiecha and Eyach in the area of the Swabian Alb and were equipped with a powdered activated carbon stage 20 years ago, which was originally aimed at reducing the release of stains from the textile industry. Several endpoints of embryo toxicity including mortality, malformations, reduced hatching rate, and heart rate were investigated at defined time points of embryonic development. Higher embryotoxic potentials were found in water and sediments collected downstream of the WWTPs equipped with sand filtration than in the sample obtained downstream of both WWTPs upgraded with a powdered activated carbon stage.

Water quality assessment in the "German River of the years 2014/2015": how a case study on the impact of a storm water sedimentation basin displayed impairment of fish health in the Argen River (Southern Germany).

PubMed

Thellmann, Paul; Kuch, Bertram; Wurm, Karl; Köhler, Heinz-R; Triebskorn, Rita

2017-01-01

The present work investigates the impact of discharges from a storm water sedimentation basin (SSB) receiving runoff from a connected motorway in southern Germany. The study lasted for almost two years and was aimed at assessing the impact of the SSB on the fauna of the Argen River, which is a tributary of Lake Constance. Two sampling sites were examined up- and downstream of the SSB effluent. A combination of different diagnostic methods (fish embryo test with the zebrafish, histopathology, micronucleus test) was applied to investigate health impairment and genotoxic effects in indigenous fish as well as embryotoxic potentials in surface water and sediment samples of the Argen River, respectively, in samples of the SSB effluent. In addition, sediment samples from the Argen River and tissues of indigenous fish were used for chemical analyses of 33 frequently occurring pollutants by means of gas chromatography. Furthermore, the integrity of the macrozoobenthos community and the fish population were examined at both investigated sampling sites. The chemical analyses revealed a toxic burden with trace substances (originating from traffic and waste water) in fish and sediments from both sampling sites. Fish embryo tests with native sediment and surface water samples resulted in various embryotoxic effects in exposed zebrafish embryos (Fig. 1). In addition, the health condition of the investigated fish species (e.g., severe alterations in the liver and kidney) provided clear evidence of water contamination at both Argen River sites (Fig. 2). At distinct points in time, some parameters (fish development, kidney and liver histopathology) indicated stronger effects at the sampling site downstream of the SSB effluent than at the upstream site. Our results clearly showed that the SSB cannot be assigned as the main source of pollutants that are released into the investigated Argen River section. Moreover, we showed that there is moderate background pollution with substances originating from waste waters and traffic which still should be taken seriously, particularly with regard to the impairment of fish health at both investigated field sites. Since the Argen is a tributary of Lake Constance, our results call for a management plan to ensure and improve the river's ecological stability.

Effect of eco-remediation using planted floating bed system on nutrients and heavy metals in urban river water and sediment: a field study in China.

PubMed

Ning, Daliang; Huang, Yong; Pan, Ruisong; Wang, Fayuan; Wang, Hui

2014-07-01

To investigate the effect of the eco-remediation on nutrients and heavy metals in river water and sediment, a field study was carried out in a site of a 2-year eco-remediation mainly using planted floating bed system in an urban river in China. Before remediation, the tested properties of water and sediment in the will-be remediated area were not different from the control area, except higher concentrations of chemical oxygen demand (COD) and total nitrogen (TN) in the river water. After remediation, the remediation area showed effective removal of in-stream nutrients and elevation of dissolved oxygen and transparency. Compared to the control area, the remediation area had higher concentration of nitrate and lower concentrations of COD, ammonium, Mn and hexavalent Cr in the river water after a 2-year remediation. The remediation area also showed higher concentrations of organic carbon, TN, nitrate, sulfate, Fe, Cu, Pb and Zn in the sediment than in the control area. Accordingly, special attention should be paid to the ecological risk of heavy metals in sediments and plants in river eco-remediation projects especially in rivers polluted by heavy metals, although the metals were lower than the level of considerable ecological risk in this study. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantifying hyporheic exchange in a karst stream using 222Rn

NASA Astrophysics Data System (ADS)

Khadka, M. B.; Martin, J. B.; Kurz, M. J.

2013-12-01

The hyporheic zone is a critical interface between groundwater and river water environments and is characterized by steep biogeochemical gradients. Understanding how this interface affects solute transport, nutrient cycling and contaminant attenuation is essential for better water resource management of streams. However, this understanding is constrained due to difficulty associated with quantification of exchange of water through the hyporheic zone. We tested a radon (222Rn) method to estimate the hyporheic water residence time and exchange rate in the bottom sediment of the spring-fed Ichetucknee River, north-central Florida. The river, which flows over the top of the unconfined karstic Floridan Aquifer, is characterized by a broad bedrock channel partially in-filled with unconsolidated sediments. Radon (222Rn) activity in the pore waters of the channel sediments differs from the amount expected from sediment production and decay. Although most radon in streams originates from sources in bottom sediments, the Ichetucknee River water has 222Rn activities (251×5 PCi/L) that are nearly twice that of the pore water (128×15 PCi/L). The river water 222Rn activity is consistent with that of the source springs, suggesting the source of Rn in the river is from deep within the aquifer rather than bottom sediments and that the excess 222Rn in the pore water results from hyporheic exchange. Profiles of radon concentrations with depth through the sediments show that the mixing of stream water and pore water extends 35-45 cm below the sediment and water interface. Based on a model that integrates the excess radon with depth, we estimate the water exchange rate to be between 1.1 and 1.6 cm/day with an average value of 1.3×0.2 cm/day. Water that exchanges across the sediment-water interface pumps oxygen into the sediments, thereby enhancing organic carbon remineralization, as well as the production of NH4+ and PO43- and their fluxes from sediments to the stream. As opposed to conventional in-stream tracer injection method which estimates exchange between the stream and both the hyporheic zone and the surface transient storage zone, the 222Rn approach measures the water exchange between stream and hyporheic sediments only. Although the present method is tested on a spring-fed karst stream, it has potential for any freshwater system (e.g. wetland, lake) where distinct radon activity and production between surface water and underlying sediments occur.

Legacy sediment storage in New England river valleys: anthropogenic processes in a postglacial landscape

NASA Astrophysics Data System (ADS)

Snyder, N. P.; Johnson, K. M.; Waltner, M.; Hopkins, A. J.; Dow, S.; Ames, E.; Merritts, D. J.; Walter, R. C.; Rahnis, M. A.

2016-12-01

Walter and Merritts (2008, and subsequent papers) show that legacy sediment associated with deposition in millponds is a common feature in river valleys of the Mid-Atlantic Piedmont region, with 1-5 m of fine sand and silt overlying Holocene soil and Pleistocene periglacial deposits. For this project, we seek to test the hypothesis that these field relationships are seen in New England, a formerly glaciated region with similar history and intensity of forest clearing and milldam construction during the 17-19th centuries. We study three watersheds, using field observations of bank stratigraphy, radiocarbon dating, and mapping of terraces and floodplains using lidar digital elevation models and other GIS datasets. The 68 km2 South River watershed in western Massachusetts exhibits the most extensive evidence for legacy sediment storage. We visited 17 historic dam sites in the watershed and found field evidence for fine sand and silt legacy sediment storage at 14, up to 2.2 m thick. In the 558 km2 Sheepscot River watershed in coastal Maine, we visited 12 historic dam sites, and found likely legacy sediment at six, up to 2.3 m thick. In the 171 km2 upper Charles River watershed in eastern Massachusetts, we investigated 14 dam sites, and found legacy sediment at two, up to 1.8 m thick. Stratigraphically, we identified the base of legacy sediment from a change in grain size to gravel at most sites, or to Pleistocene marine clay at some Sheepscot River sites. In the Sheepscot River, we observed cut timbers underlying historic sediment at several locations, likely associated with sawmill activities. Only at the Charles River were we able to radiocarbon date the underlying gravel (1281-1391 calibrated CE). At no site did we find a buried Holocene soil, in contrast to the field relations commonly observed in the Mid-Atlantic region. This may indicate that the New England sites have eroded to the pre-historic river bed, not floodplain surfaces. We attribute the variation in thickness and presence of legacy sediment at the New England sites to the existence or absence of upstream sediment supply in the form of thick (>5 m) glacial deposits. Of the three study watersheds, the South River has the most extensive glacial sediments, having been occupied by one or more ice-dammed lakes during the late Pleistocene, and the most legacy sediment storage.

Sediment quality in the north coastal basin of Massachusetts, 2003

USGS Publications Warehouse

Breault, Robert F.; Ashman, Mary S.; Heath, Douglas

2004-01-01

The U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, completed a reconnaissance-level study of bottom-sediment quality in selected lakes, rivers, and estuaries in the North Coastal Basin of Massachusetts. Bottom-sediment grab samples were collected from 20 sites in the North River, Lake Quannapowitt, Saugus River, Mill River, Shute Brook, Sea Plane Basin, Pines River, and Bear Creek. The samples were tested for various types of potentially harmful contaminants? including 33 elements, 17 polyaromatic hydrocarbons (PAHs), 22 organochlorine pesticides, and 7 polychlorinated biphenyl (PCB) mixtures (Aroclors)?to benthic organisms (bottom-dwelling) and humans. The results were compared among sampling sites, to background concentrations, and to concen-trations measured in other urban rivers, and sediment-quality guidelines were used to predict toxicity at the sampling sites to benthic organisms and humans. Because there are no standards for human toxicity for aquatic sediment, standards for contaminated upland soil were used. Contaminant concentrations measured in sediment collected from the North Coastal Basin generally were equal to or greater than concentrations in sediment from uncontaminated rivers throughout New England. Contaminants in North Coastal Basin sediment with elevated concentrations (above back-ground levels) included arsenic, chromium, copper, lead, nickel, and zinc, some of the PAHs, dichlorodiphenyltrichloro-ethane (DDT) and its metabolites, and dieldrin. No PCBs were measured above the detection limits. Measured concentrations of arsenic, chromium, and lead were also generally greater than those measured in other urban rivers throughout the conter-minous United States. With one exception (arsenic), local con-centrations measured in sediment samples collected from the North Coastal Basin were lower than concentrations measured in sediment collected from two of three urban rivers draining to Boston Harbor. The probable toxicity to benthic organisms ranged from about 33 to 91 percent across the study area. Of the elements analyzed, antimony, arsenic, beryllium, and lead exceeded the soil standards for risk to human health. Of the PAHs analyzed, four also exceeded soil standards. Organochlorine pesticide concentrations, however, were not high enough relative to the soil standards to pose a risk to human health. Some trace element and some organic compound concentrations in bottom sediment may be toxic to aquatic organisms and may pose a risk to human health.

Effect of human activities on overall trend of sedimentation in the lower Yellow River, China.

PubMed

Jiongxin, Xu

2004-05-01

The Yellow River has been intensively affected by human activities, particularly in the past 50 years, including soil-water conservation in the upper and middle drainage basin, flood protection in the lower reaches, and flow regulation and water diversion in the whole drainage basin. All these changes may impact sedimentation process of the lower Yellow River in different ways. Assessing these impacts comprehensively is important for more effective environmental management of the drainage basin. Based on the data of annual river flow, sediment load, and channel sedimentation in the lower Yellow River between 1950 and 1997, the purpose of this paper is to analyze the overall trend of channel sedimentation rate at a time scale of 50 years, and its formative cause. It was found in this study that erosion control measures and water diversion have counteractive impacts on sedimentation rate in the lower Yellow River. Although both annual river flow and sediment decreased, there was no change in channel sedimentation rate. A regression analysis indicated that the sedimentation in the lower Yellow River decreased with the sediment input to the lower Yellow River but increased with the river flow input. In the past 30-40 years, the basin-wide practice of erosion and sediment control measures resulted in a decline in sediment supply to the Yellow River; at the same time, the human development of water resources that required river flow regulation and water diversion caused great reduction in river flow. The former may reduce the sedimentation in the lower Yellow River, but the reduction of river flow increased the sedimentation. When their effects counterbalanced each other, the overall trend of channel sedimentation in the lower Yellow River remained unchanged. This fact may help us to better understand the positive and negative effects of human activities in the Yellow River basin and to pay more attention to the negative effect of the development of water resources. The results of this study demonstrate that, if the overuse of river water cannot be controlled, the reduction of channel sedimentation in the lower Yellow River cannot be realized through the practice of erosion and sediment control measures.

Modal analysis of annual runoff volume and sediment load in the Yangtze river-lake system for the period 1956-2013.

PubMed

Chen, Huai; Zhu, Lijun; Wang, Jianzhong; Fan, Hongxia; Wang, Zhihuan

2017-07-01

This study focuses on detecting trends in annual runoff volume and sediment load in the Yangtze river-lake system. Times series of annual runoff volume and sediment load at 19 hydrological gauging stations for the period 1956-2013 were collected. Based on the Mann-Kendall test at the 1% significance level, annual sediment loads in the Yangtze River, the Dongting Lake and the Poyang Lake were detected with significantly descending trends. The power spectrum estimation indicated predominant oscillations with periods of 8 and 20 years are embedded in the runoff volume series, probably related to the El Niño Southern Oscillation (2-7 years) and Pacific Decadal Oscillation (20-30 years). Based on dominant components (capturing more than roughly 90% total energy) extracted by the proper orthogonal decomposition method, total change ratios of runoff volume and sediment load during the last 58 years were evaluated. For sediment load, the mean CRT value in the Yangtze River is about -65%, and those in the Dongting Lake and the Poyang Lake are -92.2% and -87.9% respectively. Particularly, the CRT value of the sediment load in the channel inflow of the Dongting Lake is even -99.7%. The Three Gorges Dam has intercepted a large amount of sediment load and decreased the sediment load downstream.

Radiocesium decontamination of a riverside in Fukushima, Japan.

PubMed

Nishikiori, Tatsuhiro; Suzuki, Satoshi

2017-10-01

Extensive decontamination measures have been implemented in the area affected by the Fukushima Dai-ichi nuclear disaster. Typical decontamination measures, such as removing topsoil of several centimeters in depth, are not suitable for rivers where contaminated sediments have been deposited. A decontamination measure was tested that considered the spatial distribution of radiocesium at the lower part of a tributary of the Abukuma River in Fukushima. The radiocesium distribution in the flood channel was vertically and horizontally highly heterogeneous. In some parts, the activity concentration was high (>10 kBq/kg for 137 Cs) even at depths of 25 cm in the sediment. This may be due to plant growth in the flood channel favoring the deposition of sediment with high activity concentration. On the basis of the radiocesium distribution, the flood channel sediment was removed to a depth of 15-35 cm, which accumulated the most radiocesium (>3.0 kBq/kg for the sum of 134 Cs and 137 Cs). The upper 5 cm of soil was removed from the dike slopes. The river bed was not decontaminated because the activity concentration was low (<1 kBq/kg) in the river bed sediment and because the water shields gamma rays emitted from the sediment. The test decontamination measure reduced the air dose rate by a factor of approximately two, demonstrating the effectiveness of our measures. Annual external doses were calculated for when this part of the dike and the flood channel is used for commuting to school and outdoor education. The doses during the activities at the test site accounted for only 1-2% of the value during daily life in the surrounding area, indicating that radiation exposure during riverside activities is limited. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Sensitivity Analysis of Triggers and Mechanisms of Mass Movements in Fjords

NASA Astrophysics Data System (ADS)

Overeem, I.; Lintern, G.; Hill, P.

2016-12-01

Fjords are characterized by rapid sedimentation as they typically drain glaciated river catchments with high seasonal discharges and large sediment evacuation rates. For this reason, fjords commonly experience submarine mass movements; failures of the steep delta front that trigger tsunamis, and turbidity currents or debris flows. Repeat high-resolution bathymetric surveys, and in-situ process measurements collected in fjords in British Columbia, Canada, indicate that mass movements occur many times per year in some fjords and are more rare and of larger magnitude in other fjords. We ask whether these differences can be attributed to river discharge characteristics or to grainsize characteristics of the delivered sediment. To test our ideas, we couple a climate-driven river sediment transport model, HydroTrend, and a marine sedimentation model, Sedflux2D, to explore the triggers of submarine failures and mechanisms of subsequent turbidity and debris flows. HydroTrend calculates water and suspended sediment transport on a daily basis based on catchment characteristics, glaciated area, lakes and temperature and precipitation regime. Sedflux uses the generated river time-series to simulate delta plumes, failures and mass movements with separate process models. Model uncertainty and parameter sensitivity are assessed using Dakota Tools, which allows for a systematic exploration of the effects of river basin characteristics and climate scenarios on occurrence of hyperpycnal events, delta front sedimentation rate, submarine pore pressure, failure frequency and size, and run-out distances. Preliminary simulation results point to the importance of proglacial lakes and lakes abundance in the river basin, which has profound implications for event-based sediment delivery to the delta apex. Discharge-sediment rating curves can be highly variable based on these parameters. Distinction of turbidity currents and debris flows was found to be most sensitive to both earthquake frequency and delta front grainsize. As a first step we compare these model experiments against field data from the Squamish River and Delta in Howe Sound, BC.

Dating sediment cores from Hudson River marshes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robideau, R.; Bopp, R.F.

1993-03-01

There are several methods for determining sediment accumulation rates in the Hudson River estuary. One involves the analysis of the concentration of certain radionuclides in sediment core sections. Radionuclides occur in the Hudson River as a result of: natural sources, fallout from nuclear weapons testing and low level aqueous releases from the Indian Point Nuclear Power Facility. The following radionuclides have been studied in the authors work: Cesium-137, which is derived from global fallout that started in the 1950's and has peaked in 1963. Beryllium-7, a natural radionuclide with a 53 day half-life and found associated with very recently depositedmore » sediments. Another useful natural radionuclide is Lead-210 derived from the decay of Radon-222 in the atmosphere. Lead-210 has a half-life of 22 years and can be used to date sediments up to about 100 years old. In the Hudson River, Cobalt-60 is a marker for Indian Point Nuclear Reactor discharges. The author's research involved taking sediment core samples from four sites in the Hudson River Estuarine Research Reserve areas. These core samples were sectioned, dried, ground and analyzed for the presence of radionuclides by the method of gamma-ray spectroscopy. The strength of each current pulse is proportional to the energy level of the gamma ray absorbed. Since different radionuclides produce gamma rays of different energies, several radionuclides can be analyzed simultaneously in each of the samples. The data obtained from this research will be compared to earlier work to obtain a complete chronology of sediment deposition in these Reserve areas of the river. Core samples may then by analyzed for the presence of PCB's, heavy metals and other pollutants such as pesticides to construct a pollution history of the river.« less

Effects of sediment-bound zinc contamination on early life stages of the mummichog (Fundulus heteroclitus L.) in the Christina watershed, Delaware, U.S.A.

PubMed

Guy, Christopher Paul; Pinkney, Alfred Eli; Taylor, Malcolm Herbert

2006-05-01

During the last century, the Christina River, the major estuarine river system in New Castle County (DE, USA), has received loadings of organic and inorganic chemicals, primarily from manufacturing facilities. Among the most abundant chemicals is zinc, which has accumulated in sediments at concentrations as high as 5,440 mg/kg. We studied the possible effects of zinc on early life stages of the mummichog (Fundulus heteroclitus), a resident species in the river and watershed. We conducted three different types of exposures. The first was a 96-h median lethal concentration (LC50) test with larvae exposed to waterborne zinc. The second was a larval exposure with zinc-spiked sediments (obtained from the relatively uncontaminated Magothy River in Anne Arundel County, MD, USA). The third was an embryo-larval exposure with Christina River sediments having a gradient of zinc concentrations. The average 96-h LC50 with newly hatched yolk sac larvae was 970 lig/L. In the larval tests, the average 7- and 21-d LC50s were 1154 and 1012 mg/kg, respectively. In the embryo-larval test, no significant difference was found in survival at concentrations between 38.8 and 1098 mg/kg. However, significant reductions were observed in condition factor at concentrations of 582, 799, and 1098 mg/kg. We calculated an average no-observed-effects concentration of 579 mg/kg and an average lowest-observed-effects concentration of 849 mg/kg for larval survival. Based on these results, we suggest that zinc in the Christina River may be affecting early life stages of the mummichog.

Bioavailability of sediment-associated mercury to Hexagenia mayflies in a contaminated floodplain river

USGS Publications Warehouse

Naimo, T.J.; Wiener, J.G.; Cope, W.G.; Bloom, N.S.

2000-01-01

We examined the bioavailability of mercury in sediments from the contaminated Sudbury River (Massachusetts, U.S.A.). Mayfly nymphs (Hexagenia) were exposed in four 21-day bioaccumulation tests to contaminated and reference sediments (treatments) from reservoirs, flowing reaches, palustrine wetlands, and a riverine lake. Mean total mercury (Sigma Hg) ranged from 880 to 22 059 ng.g dry weight(-1) in contaminated sediments and from 90 to 272 ng.g(-1) in reference sediments. Mean final concentrations of methyl mercury (MeHg) in test water were greatest (8-47 ng Hg.L-1) in treatments with contaminated wetland sediments, which had mean Sigma Hg ranging from 1200 to 2562 ng.g(-1). In mayflies, final mean concentrations of MeHg were highest in treatments with contaminated wetland sediments (122-183 ng Hg.g(-1)), intermediate in treatments with contaminated sediments from reservoirs, flowing reaches, and a riverine lake (75-127 ng Hg.g(-1)), and lowest in treatments with reference sediments (32-41 ng Hg.g(-1)). We conclude that the potential entry of MeHg into the benthic food chain was greater in contaminated palustrine wetlands than in the contaminated reservoirs, which had the most contaminated sediments.

Gene expression profiling to characterize sediment toxicity – a pilot study using Caenorhabditis elegans whole genome microarrays

PubMed Central

Menzel, Ralph; Swain, Suresh C; Hoess, Sebastian; Claus, Evelyn; Menzel, Stefanie; Steinberg, Christian EW; Reifferscheid, Georg; Stürzenbaum, Stephen R

2009-01-01

Background Traditionally, toxicity of river sediments is assessed using whole sediment tests with benthic organisms. The challenge, however, is the differentiation between multiple effects caused by complex contaminant mixtures and the unspecific toxicity endpoints such as survival, growth or reproduction. The use of gene expression profiling facilitates the identification of transcriptional changes at the molecular level that are specific to the bio-available fraction of pollutants. Results In this pilot study, we exposed the nematode Caenorhabditis elegans to three sediments of German rivers with varying (low, medium and high) levels of heavy metal and organic contamination. Beside chemical analysis, three standard bioassays were performed: reproduction of C. elegans, genotoxicity (Comet assay) and endocrine disruption (YES test). Gene expression was profiled using a whole genome DNA-microarray approach to identify overrepresented functional gene categories and derived cellular processes. Disaccharide and glycogen metabolism were found to be affected, whereas further functional pathways, such as oxidative phosphorylation, ribosome biogenesis, metabolism of xenobiotics, aging and several developmental processes were found to be differentially regulated only in response to the most contaminated sediment. Conclusion This study demonstrates how ecotoxicogenomics can identify transcriptional responses in complex mixture scenarios to distinguish different samples of river sediments. PMID:19366437

Evaluation of dredged material proposed for ocean disposal from Bronx River Project Area, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gruendell, B.D.; Gardiner, W.W.; Antrim, L.D.

1996-12-01

The objective of the Bronx River project was to evaluate proposed dredged material from the Bronx River project area in Bronx, New York, to determine its suitability for unconfined ocean disposal at the Mud Dump Site. Bronx River was one of five waterways that the US Army Corps of Engineers-New York District (USAGE-NYD) requested the Battelle Marine Sciences Laboratory (MSL) to sample and to evaluate for dredging and disposal. Sediment samples were submitted for physical and chemical analyses, chemical analyses of dredging site water and elutriate, benthic and water-column acute toxicity tests, and bioaccumulation studies. Fifteen individual sediment core samplesmore » collected from the Bronx River project area were analyzed for grain size, moisture content, and total organic carbon (TOC). One composite sediment sample, representing the entire reach of the area proposed for dredging, was analyzed for bulk density, specific gravity, metals, chlorinated pesticides, polychlorinated biphenyl (PCB) congeners, polynuclear aromatic hydrocarbons (PAH), and 1,4- dichlorobenzene. Dredging site water and elutriate water, which was prepared from the suspended-particulate phase (SPP) of the Bronx River sediment composite, were analyzed for metals, pesticides, and PCBS.« less

Field and flume investigations of the effects of logjams and woody debris on streambed morphology

NASA Astrophysics Data System (ADS)

Leung, V.; Montgomery, D. R.; McHenry, M. L.

2014-12-01

Interactions among wood debris, fluid flow and sediment transport in rivers are first-order controls on channel morphodynamics, affecting streambed morphology, sediment transport, sediment storage and aquatic habitat. Woody debris increases the hydraulic and topographic complexity in rivers, leading to a greater diversity of aquatic habitats and an increase in the number of large pools that are important fish habitat and breeding grounds. In the past decade, engineered logjams have become an increasingly used tool in river management for simultaneously decreasing the rate of riverbank migration and improving aquatic habitat. Sediment deposits around woody debris build up riverbanks and counteract bank migration caused by erosion. Previous experiments on flow visualization around model woody debris suggest the amount of sediment scour and deposition are primarily related to the presence of roots and the obstructional area of the woody debris. We present the results of fieldwork and sediment transport experiments of streambed morphology around stationary woody debris. Field surveys on the Hoh River and the Elwha River, WA, measure the local streambed morphology around logjams and individual pieces of woody debris. We quantified the amount of local scour and dam-removal related fine sediment deposition around natural and engineered logjams of varying sizes and construction styles, located in different geomorphic settings. We also quantified the amount of local scour around individual pieces of woody debris of varying sizes, geometries and orientations relative to flow. The flume experiments tested the effects of root geometry and log orientation of individual stationary trees on streambed morphology. The flume contained a deformable sediment bed of medium sand. We find that: 1) the presence of roots on woody debris leads to greater areas of both sediment scour and deposition; and 2) the amount of sediment scour and deposition are related to the wood debris cross-sectional area, oriented orthogonal to flow. A better understanding of the underlying sediment physics and hydraulics around naturally occurring woody debris in rivers can provide guidance and criteria for use in river restoration and engineering as well as scientific insights into a complex interdisciplinary problem.

Subsoil erosion dominates the supply of fine sediment to rivers draining into Princess Charlotte Bay, Australia.

PubMed

Olley, Jon; Brooks, Andrew; Spencer, John; Pietsch, Timothy; Borombovits, Daniel

2013-10-01

The Laura-Normanby River (catchment area: 24,350 km(2)), which drains into Princess Charlotte Bay, has been identified in previous studies as the third largest contributor of sediment to the Great Barrier Reef World Heritage Area. These catchment scale modelling studies also identified surface soil erosion as supplying >80% of the sediment. Here we use activity concentrations of the fallout radionuclides (137)Cs and (210)Pbex to test the hypothesis that surface soil erosion dominates the supply of fine (<10 μm) sediment in the river systems draining into Princess Charlotte Bay. Our results contradict these previous studies, and are consistent with channel and gully erosion being the dominant source of fine sediment in this catchment. The hypothesis that surface soil erosion dominates the supply of fine sediment to Princess Charlotte Bay is rejected. River sediment samples were collected using both time-integrated samplers and sediment drape deposits. We show that there is no detectable difference in (137)Cs and (210)Pbex activity concentrations between samples collected using these two methods. Two methods were also used to collect samples to characterise (137)Cs and (210)Pbex concentrations in sediment derived from surface soil erosion; sampling of surface-wash deposits and deployment of surface runoff traps that collected samples during rain events. While there was no difference in the (137)Cs activity concentrations for samples collected using these two methods, (210)Pbex activity concentrations were significantly higher in the samples collected using the runoff traps. The higher (210)Pbex concentrations are shown to be correlated with loss-on-ignition (r(2) = 0.79) and therefore are likely to be related to higher organic concentrations in the runoff trap samples. As a result of these differences we use a three end member mixing model (channel/gully, hillslope surface-wash and hillslope runoff traps) to determine the relative contribution from surface soil erosion. Probability distributions for (137)Cs and (210)Pbex concentrations were determined for each of the end members, with these distributions then used to estimate the surface soil contribution to each of the collected river sediment samples. The mean estimate of contribution of surface derived sediment for all river samples (n = 70) is 16 ± 2%. This study reinforces the importance of testing model predictions before they are used to target investment in remedial action and adds to the body of evidence that the primary source of sediment delivered to tropical river systems is derived from subsoil erosion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Suspended-sediment loads from major tributaries to the Missouri River between Garrison Dam and Lake Oahe, North Dakota, 1954-98

USGS Publications Warehouse

Macek-Rowland, Kathleen M.

2000-01-01

Annual suspended-sediment loads for water years 1954 through 1998 were estimated for the major tributaries in the Missouri River Basin between Garrison Dam and Lake Oahe in North Dakota and for the Missouri River at Garrison Dam and the Missouri River at Bismarck, N. Dak.  The major tributaries are the Knife River, Turtle Creek, Painted Woods Creek, Square Butte Creek, Burnt Creek, Heart River, and Apple Creek.  Sediment and streamflow data used to estimate the suspended-sediment loads were from selected U.S. Geological Survey streamflow-gaging stations located within each basin.  Some of the stations had no sediment data available and limited continuous streamflow data for water years 1954 through 1998.  Therefore, data from nearby streamflow-gaging stations were assumed for the calculations. The Heart River contributed the largest amount of suspended sediment to the Missouri River for 1954-98.  Annual suspended-sediment loads in the Heart River near Mandan ranged from less than 1 to 40 percent of the annual suspended-sediment load in the Missouri River. The Knife River contributed the second largest amount of suspended sediment to the Missouri River.  Annual suspended-sediment loads in the Knife River at Hazen ranged from less than 1 to 19 percent of the annual suspended-sediment load in the Missouri River.  Apple Creek, Turtle Creek, Painted Woods Creek, Square Butte Creek, and Burnt Creek all contributed 2 percent or less of the annual suspended-sediment load in the Missouri River.  The Knife River and the Heart River also had the largest average suspended-sediment yields for the seven tributaries.  The yield for the Knife River was 91.1 tons per square mile, and the yield for the Heart River was 133 tons per square mile.  The remaining five tributaries had yields of less than 24 tons per square mile based on total drainage area. 

Laboratory and field measurements of upwelled radiance and reflectance spectra of suspended James River sediments near Hopewell, Virginia

NASA Technical Reports Server (NTRS)

Whilock, C. H.; Witte, W. G.; Gurganus, E. A.; Usry, J. W.

1978-01-01

Spectral reflectance characteristics of suspended Bermuda Hundred and Bailey Bay bottom sediments taken from the Hopewell, Va., area were measured in the laboratory for water mixture total suspended solids concentrations between 4 and 173 parts per million. Field spectral reflectance measurements were made of the James River waters near Bermuda Hundred on two occasions. The results of these tests indicate that both Bermuda Hundred and Bailey Bay suspended sediments produce their strongest reflectance in the green and red regions of the spectrum.

Trends in the suspended-sediment yields of coastal rivers of northern California, 1955–2010

USGS Publications Warehouse

Warrick, J.A.; Madej, Mary Ann; Goñi, M. A.; Wheatcroft, R.A.

2013-01-01

Time-dependencies of suspended-sediment discharge from six coastal watersheds of northern California – Smith River, Klamath River, Trinity River, Redwood Creek, Mad River, and Eel River – were evaluated using monitoring data from 1955 to 2010. Suspended-sediment concentrations revealed time-dependent hysteresis and multi-year trends. The multi-year trends had two primary patterns relative to river discharge: (i) increases in concentration resulting from both land clearing from logging and the flood of record during December 1964 (water year 1965), and (ii) continual decreases in concentration during the decades following this flood. Data from the Eel River revealed that changes in suspended-sediment concentrations occurred for all grain-size fractions, but were most pronounced for the sand fraction. Because of these changes, the use of bulk discharge-concentration relationships (i.e., “sediment rating curves”) without time-dependencies in these relationships resulted in substantial errors in sediment load estimates, including 2.5-fold over-prediction of Eel River sediment loads since 1979. We conclude that sediment discharge and sediment discharge relationships (such as sediment rating curves) from these coastal rivers have varied substantially with time in response to land use and climate. Thus, the use of historical river sediment data and sediment rating curves without considerations for time-dependent trends may result in significant errors in sediment yield estimates from the globally-important steep, small watersheds.

10Be constrains the sediment sources and sediment yields to the Great Barrier Reef from the tropical Barron River catchment, Queensland, Australia

NASA Astrophysics Data System (ADS)

Nichols, K. K.; Bierman, P. R.; Rood, D. H.

2014-12-01

Estimates of long-term, background sediment generation rates place current and future sediment fluxes to the Great Barrier Reef in context. Without reliable estimates of sediment generation rates and without identification of the sources of sediment delivered to the reef prior to European settlement (c. 1850), determining the necessity and effectiveness of contemporary landscape management efforts is difficult. Using the ~2100-km2 Barron River catchment in Queensland, Australia, as a test case, we use in situ-produced 10Be to derive sediment generation rate estimates and use in situ and meteoric 10Be to identify the source of that sediment, which enters the Coral Sea near Cairns. Previous model-based calculations suggested that background sediment yields were up to an order of magnitude lower than contemporary sediment yields. In contrast, in situ 10Be data indicate that background (43 t km-2 y-1) and contemporary sediment yields (~45 t km-2 y-1) for the Barron River are similar. These data suggest that the reef became established in a sediment flux similar to what it receives today. Since western agricultural practices increased erosion rates, large amounts of sediment mobilized from hillslopes during the last century are probably stored in Queensland catchments and will eventually be transported to the coast, most likely in flows triggered by rare but powerful tropical cyclones that were more common before European settlement and may increase in strength as climate change warms the south Pacific Ocean. In situ and meteoric 10Be concentrations of Coral Sea beach sand near Cairns are similar to those in rivers on the Atherton Tablelands, suggesting that most sediment is derived from the extensive, low-gradient uplands rather than the steep, more rapidly eroding but beach proximal escarpment.

Implementation of sediment dynamics in a global integrated assessment model for an improved simulation of nutrient retention and transfers in surface freshwaters

NASA Astrophysics Data System (ADS)

Vilmin, L.; Beusen, A.; Mogollón, J.; Bouwman, L.

2017-12-01

Sediment dynamics play a significant role in river biogeochemical functioning. They notably control the transfer of particle-bound nutrients, have a direct influence on light availability for primary production, and particle accumulation can affect oxic conditions of river beds. In the perspective of improving our current understanding of large scale nutrient fluxes in rivers, it is hence necessary to include these dynamics in global models. In this scope, we implement particle accumulation and remobilization in a coupled global hydrology-nutrient model (IMAGE-GNM), at a spatial resolution of 0.5°. The transfer of soil loss from natural and agricultural lands is simulated mechanistically, from headwater streams to estuaries. First tests of the model are performed in the Mississippi river basin. At a yearly time step for the period 1978-2000, the average difference between simulated and measured suspended sediment concentrations at the most downstream monitoring station is 25%. Sediment retention is estimated in the different Strahler stream orders, in lakes and reservoirs. We discuss: 1) the distribution of sediment loads to small streams, which has a significant effect on transfers through watersheds and larger scale river fluxes and 2) the potential effect of damming on the fate of particle-bound nutrients. These new developments are crucial for future assessments of large scale nutrient and carbon fluxes in river systems.

Chemical and ecotoxicological analyses of sediments and elutriates of contaminated rivers due to e-waste recycling activities using a diverse battery of bioassays.

PubMed

Wang, F; Leung, A O W; Wu, S C; Yang, M S; Wong, M H

2009-07-01

A multi-trophic, multi-exposure phase assessment approach was applied to characterize the toxicity of sediments collected from two rivers in Guiyu, China, an e-waste recycling centre. Elutriate toxicity tests (bacterium Vibrio fischeri and microalga Selenastrum capricornutum) and whole sediment toxicity test (crustacean Heterocypris incongruens) showed that most sediments exhibited acute toxicity, due to elevated heavy metals and PAHs levels, and low pH caused by uncontrolled acid discharge. The survival rates of crustaceans were negatively (p < 0.05) correlated with total PAHs in sediments (411-1755 mg kg(-1)); EC50s of V. fischeri on the elutriates were significantly correlated with elutriate pH (p < 0.01). Significant (p < 0.05) correlations between the induction of hepatic metallothionein in tilapia (Oreochromis mossambicus) and metal concentrations (Cu, Zn, Pb) in sediments were also observed, when fish were fed with diets containing sediment. The results showed that uncontrolled e-waste recycling activities may bring adverse effects to local aquatic ecosystem.

Suspended-sediment concentrations, bedload, particle sizes, surrogate measurements, and annual sediment loads for selected sites in the lower Minnesota River Basin, water years 2011 through 2016

USGS Publications Warehouse

Groten, Joel T.; Ellison, Christopher A.; Hendrickson, Jon S.

2016-12-20

Accurate measurements of fluvial sediment are important for assessing stream ecological health, calculating flood levels, computing sediment budgets, and managing and protecting water resources. Sediment-enriched rivers in Minnesota are a concern among Federal, State, and local governments because turbidity and sediment-laden waters are the leading impairments and affect more than 6,000 miles of rivers in Minnesota. The suspended sediment in the lower Minnesota River is deleterious, contributing about 75 to 90 percent of the suspended sediment being deposited into Lake Pepin. The Saint Paul District of the U.S. Army Corps of Engineers and the Lower Minnesota River Watershed District collaborate to maintain a navigation channel on the lower 14.7 miles of the Minnesota River through scheduled dredging operations. The Minnesota Pollution Control Agency has adopted a sediment-reduction strategy to reduce sediment in the Minnesota River by 90 percent by 2040.The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, the Minnesota Pollution Control Agency, and the Lower Minnesota River Watershed District, collected suspended-sediment, bedload, and particle-size samples at five sites in the lower Minnesota River Basin during water years 2011 through 2014 and surrogate measurements of acoustic backscatter at one of these sites on the lower Minnesota River during water years 2012 through 2016 to quantify sediment loads and improve understanding of sediment-transport relations. Annual sediment loads were computed for calendar years 2011 through 2014.Data collected from water years 2011 through 2014 indicated that two tributaries, Le Sueur River and High Island Creek, had the highest sediment yield and concentrations of suspended sediment. These tributaries also had greater stream gradients than the sites on the Minnesota River. Suspended fines were greater than suspended sand at all sites in the study area. The range of median particle sizes matched the range for stream gradients from greatest to smallest. Bedload ranged from 3 to 20 percent of the total load at the Le Sueur River, Minnesota River at Mankato, and High Island Creek and was less than 1 percent of the total load at the Minnesota River near Jordan and at Fort Snelling State Park. The reach of the Minnesota River between Mankato and Jordan is a major source of sediment, with the sediment yield at Jordan being two and a half times greater than at Mankato. Between Jordan and Fort Snelling, the sediment yield decreases substantially, which indicates that the Minnesota River in this reach is a sink for sediment. Surrogate measurements (acoustic backscatter) collected with suspended-sediment concentration data from water years 2012 through 2016 from the Minnesota River at Fort Snelling State Park indicated strong relations between the acoustic backscatter and suspended-sediment concentrations. These results point to the dynamic nature of sediment aggradation, degradation, and transport in the Minnesota River Basin. The analyses described in this report will improve the understanding of sediment-transport relations and sediment budgets in the Minnesota River Basin.

Maximum Flow Efficiency in an Anabranching River, Magela Creek, Northern Australia

NASA Astrophysics Data System (ADS)

Jansen, J. D.; Nanson, G. C.

2002-12-01

In this field- and laboratory-based study, we demonstrate that the development of anabranching channels in some rivers increases the conveyance of sediment and water, compared with a single channel at the same flow discharge. That is, under certain conditions, anabranching channels exhibit greater sediment transporting capacity per unit available stream power. Anabranching is a globally widespread river pattern noted in diverse physiographic, hydrologic and sedimentologic environments, and recent efforts have sought to unravel controls on their origin and maintenance. It is widely held that most rivers form a single-channel in order to minimise boundary roughness while conveying water and sediment, but do all rivers show a tendency to develop a single channel? And if so, what factors lead to long-term anabranching? The observation that anabranching commonly develops in environments where water and sediment conveyance is maintained with little or no recourse to increasing energy slope prompted the hypothesis that rivers may adopt a multiple channel pattern in order to optimise their efficiency where they cannot otherwise increase slope. It is reasoned that development of a system of multiple channels reduces total flow width and raises mean flow depth, thereby maximising sediment transport per unit area of the channel bed and maintaining or enhancing water and sediment throughput. In testing the hypothesis we present: (1) results of a field experiment in which hydraulic variables and bedload discharge are measured and compared for single-channel versus multichannel reaches of the same river (Magela Creek, northern Australia); (2) comparison of these field results with bedload transport modelling via well known bedload equations; and (3) results of an experimental flume study comparing hydraulic variables and sediment flux in single-channel versus divided flow. Magela Creek is representative of several anabranching systems draining the Alligators Rivers Region of monsoonal northern Australia. We investigate the dynamics of flows up to four-times bankfull discharge and find that at high flowstage hydraulic variables interact in a complicated manner that precludes conventional hydraulic geometry analytical methods. The complex trends among hydraulic variables reflect the differential and stage-dependent interactions between bank vegetation and channel roughness. Abrupt decline in overbank velocity promotes proximal sedimentation in the form of vertically-accreting islands, levees and sand splays - mechanisms of sediment sequestration that may eventually lead to channel avulsion and creation of new channels. Given that river pattern reveals much about river dynamics, the prevalence of anabranching - particularly among the world's largest rivers - invites the speculation that a fundamental physical principle may underpin the widespread adoption of anabranching; it may be the most efficient means of transmitting large water and sediment discharges in alluvial rivers. However, just as different equilibrium states are expected to exist in braiding, meandering and straight rivers, we anticipate that other anabranching rivers may differ in their efficiency. Moreover, the development of sediment and water flux imbalances between anabranches is a highly likely outcome of their independent functioning. Channel atrophy coupled with in-channel sedimentation lies at the heart of channel avulsion and abandonment processes and therefore is central to the anabranching pattern.

Assessment of the Efficiency of Sediment Deposition Reduction in the Zengwen River Watershed in Taiwan

NASA Astrophysics Data System (ADS)

Wu, M.; Tan, H. N.; Lo, W. C.; Tsai, C. T.

2015-12-01

The river upstream of watersheds in Taiwan is very steep, where soil and rock are often unstable so that the river watershed typically has the attribute of high sand yield and turbid runoff due to the excessive erosion in the heavy rainfall seasons. If flood water overflows the river bank, it would lead to a disaster in low-altitude plains. When flood retards or recesses, fine sediment would deposit. Over recent decades, many landslides arise in the Zengwen river watershed due to climate changes, earthquakes, and typhoons. The rocks and sands triggered by these landslides would move to the river channel through surface runoff, which may induce sediment disasters and also render an impact on the stability and sediment transport of the river channel. The risk of the sediment disaster could be reduced by implementing dredging works. However, because of the nature of the channel, the dredged river sections may have sediment depositions back; thus, causing an impact on flood safety. Therefore, it is necessary to evaluate the effectiveness of dredged works from the perspectives of hydraulic, sediment transport, and flood protection to achieve the objective of both disaster prevention and river bed stability. We applied the physiographic soil erosion-deposition (PSED) model to simulate the sediment yield, the runoff, and sediment transport rate of the Zengwen river watershed corresponding to one-day rainstorms of the return periods of 25, 50, and 100 year. The potential of sediment deposition and erosion in the river sections of the Zengwen river could be simulated by utilizing the alluvial river-movable bed two dimensional (ARMB-2D) model. The results reveal that the tendency for the potential of river sediment deposition and erosion obtained from these two models is agreeable. Furthermore, in order to evaluate the efficiency of sediment deposition reduction, two quantized values, the rate of sediment deposition reduction and the ratio of sediment deposition reduction were utilized. According to the simulation results obtained from the PESD and ARMB-2D models, the river sections with severe sediment depositions and high efficiency of sediment deposition reduction will be referred to as the dredging-to-be areas.

Regional Sediment Management (RSM) Modeling Tools: Integration of Advanced Sediment Transport Tools into HEC-RAS

DTIC Science & Technology

2014-06-01

Integration of Advanced Sediment Transport Tools into HEC-RAS by Paul M. Boyd and Stanford A. Gibson PURPOSE: This Coastal and Hydraulics Engineering...Technical Note (CHETN) summarizes the development and initial testing of new sediment transport and modeling tools developed by the U.S. Army Corps...sediment transport within the USACE HEC River Analysis System (HEC-RAS) software package and to determine its applicability to Regional Sediment

The influence of the macro-sediment from the mountainous area to the river morphology in Taiwan

NASA Astrophysics Data System (ADS)

Chen, S. C.; Wu, C.; Shih, P.

2012-12-01

Chen, Su-Chin scchen@nchu.edu.tw Wu, Chun-Hung* chwu@mail.nchu.edu.tw Dept. Soil & Water Conservation, National Chung Hsing University, Taichung, Taiwan. The Chenyulan River was varied changed with the marco-sediment yielded source area, Shenmu watershed, with 10 debris flow events in the last decade, in Central Taiwan. Multi-term DEMs, the measurement data of the river topographic profile and aerial photos are adopted to analyze the decade influences of the marco-sediment to the river morphology in Chenyulan River. The changes of river morphology by observing the river pattern, calculating the multi-term braided index, and estimating the distribution of sediment deposition and main channel in the river. The response for the macro-sediment from the mountainous areas into the river in the primary stage is the increase in river width, the depth of sediment deposition and volume of sediment transport. The distribution of sediment deposition from upstream landslide and river bank erosion along the river dominates the change of river morphology in the primary stage. The river morphology achieves stable gradually as the river discharge gradually decreases in the later stage. Both of the braided index and the volume of sediment transport decrease, and the river flow maintains in a main channel instead of the braided pattern in this stage. The decade sediment deposition depth is estimated as > 0.5 m, especially > 3.5 m in the sections closed to the sediment-yield source areas, the mean river width increases 15%, and the sediment with a total volume of 8×107 tons has been transported in last decade in Chenyulan River. The river morphology in Chenyulan River maintains a short-term stable, i.e. 2 or 3 years, and changes again because of the flooding events with a large amount of sediment caused by frequently heavy rainfall events in Taiwan. Furthermore, the response of river morphology in Chenyulan River due to the heavy rainfall with a total precipitation of around 860 mm in 3 days in 2009 Typhoon Morakot is also discussed in the study. A extreme river discharge with the return period of 100 year transported the macro sediment with the total volume of around 3.2×107 m3 in 8 days during 2009 Typhoon Morakot, and it also resulted in 18.1% increase of the mean river width and 4 m increase of the mean scouring depth in Chenyulan River, especially the mean increase of 50 m in river width resulted from the total sediment volume of 1.9×107 m3 deposited within 8 km from the sediment-yielded area, i.e. Shenmu watershed. Furthermore, the distribution of sediment deposition in a narrow pass is also discussed in the research. Sediment deposited apparently in the upstream of a narrow pass and also results in the disordered river patterns. The high velocity flow due to the contraction of the river width in the narrow pass section also leads to the headwater erosion in the upstream of the narrow pass section. Contrarily, the unapparent sediment deposition in the downstream of the narrow pass section brings about the stable main channel and swinging flow patterns from our decade observation.

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 tributaries.

Bioavailability, ecotoxicity, and geological characteristics of trace lead in sediments from two sites on Negro River, Uruguay, South America.

PubMed

Míguez, Diana M; Huertas, Raquel; Carrara, María V; Carnikián, Agustín; Bouvier, María E; Martínez, María J; Keel, Karen; Pioda, Carolina; Darré, Elena; Pérez, Ramiro; Viera, Santiago; Massa, Enrique

2012-04-01

Bioassays of two sites along the Rio Negro in Uruguay indicate ecotoxicity, which could be attributable to trace concentrations of lead in river sediments. Monthly samples at two sites at Baygorria and Bonete locations were analyzed for both particle size and lead. Lead was determined by atomic spectrometry in river water and sediment and particle size by sieving and sedimentation. Data showed that Baygorria's sediments have greater percentage of clay than Bonete's (20.4 and 5.8%, respectively). Lead was measurable in Baygorria's sediments, meanwhile in Bonete's, it was always below the detection limit. In water samples, lead was below detection limit at both sites. Bioassays using sub-lethal growth and survival test with Hyalella curvispina amphipod, screening with bioluminescent bacteria Photobacterium leiognathi, and acute toxicity bioassay with Pimephales promelas fish indicated toxicity at Baygorria, with much less effect at Bonete. Even though no lethal effects could be demonstrated, higher sub-lethal toxicity was found in samples from Baygorria site, showing a possible concentration of the contaminant in the clay fraction.

Laboratory Alluvial Rivers

NASA Astrophysics Data System (ADS)

Devauchelle, O.; Abramian, A.; Seizilles, G.; Lajeunesse, E.

2015-12-01

By which physical mechanisms does a river select its shape and size? We investigate this question using small laboratory rivers formed by laminar flows.In its simplest form, this experiment consists in a flow of glycerol over a uniform layer of plastic sediments. After a few hours, a channel forms spontaneously, and eventually reaches a stable geometry. This equilibrium state corresponds accurately to the force balance proposed by Henderson (1961).If we impose a sediment discharge at the inlet of the experiment, the river adjusts to this boundary condition by widening its channel. Observation suggests that this new equilibrium results from the balance between gravity, which pulls the entrained grains towards the center of the channel, and bedload diffusion, which returns them towards the banks. This balance explains why experimental rivers get wider and shallower as their sediment load increases.However, to test quantitatively this theory against observation, we need to evaluate independently the effect of transverse slope on bedload transport. We propose to use an instability generated by bedload diffusion to do so.

Dispersal of river sediment in the Southern California Bight

USGS Publications Warehouse

Warrick, J.A.; Farnsworth, K.L.

2009-01-01

The rivers of Southern California deliver episodic pulses of water, sediment, nutrients, and pollutants to the region's coastal waters. Although river-sediment dispersal is observed in positively buoyant (hypopycnal) turbid plumes extending tens of kilometers from river mouths, very little of the river sediment is found in these plumes. Rather, river sediment settles quickly from hypopycnal plumes to the seabed, where transport is controlled by bottom-boundary layer processes, presumably including fluid-mud (hyperpycnal) gravity currents. Here we investigate the geographical patterns of river-sediment dispersal processes by examining suspended-sediment concentrations and loads and the continental shelf morphology offshore river mouths. Throughout Southern California, river sediment is discharged at concentrations adequately high to induce enhanced sediment settling, including negative buoyancy. The rivers draining the Western Transverse Range produce suspended-sediment concentrations that are orders of magnitude greater than those in the urbanized region and Peninsular Range to the south, largely due to differences in sediment yield. The majority of sediment discharge from the Santa Clara River and Calleguas Creek occurs above the theoretical negative buoyancy concentration (>40 g/l). These rivers also produce event sediment loading as great as the Eel River, where fluid-mud gravity currents are observed. The continental shelf of Southern California has variable morphology, which influences the ability to transport via gravity currents. Over half of the rivers examined are adjacent to shelf slopes greater than 0.01, which are adequately steep to sustain auto-suspending gravity currents across the shelf, and have little (<10 m) Holocene sediment accumulation. Shelf settings of the Ventura, Santa Clara, and Tijuana Rivers are very broad and low sloped (less than 0.004), which suggests that fluid-mud gravity currents could transport across these shelves, albeit slowly (??10 cm/s) and only with adequate wave-generated shear stress and sediment loading. Calleguas Creek is unique in that it discharges directly into a steepsloped canyon (greater than 0.1) that should allow for violent auto-suspending gravity currents. In light of this, only one shelf setting-the Santa Clara and Ventura-has considerable Holocene sediment accumulation (exceeding 60 m), and here we show that the morphology of this shelf is very similar to an equilibrium shape predicted by gravity-current sediment transport. Thus, we conclude that a wide distribution of river-shelf settings occur in the Southern California Bight, which will directly influence sediment dispersal processes-both dilute suspended and gravity-current transport-and sediment-accumulation patterns. ?? 2009 The Geological Society of America.

The natural sediment regime in rivers: broadening the foundation for ecosystem management

USGS Publications Warehouse

Wohl, Ellen E.; Bledsoe, Brian P.; Jacobson, Robert B.; Poff, N. LeRoy; Rathburn, Sara L.; Walters, David M.; Wilcox, Andrew C.

2015-01-01

Water and sediment inputs are fundamental drivers of river ecosystems, but river management tends to emphasize flow regime at the expense of sediment regime. In an effort to frame a more inclusive paradigm for river management, we discuss sediment inputs, transport, and storage within river systems; interactions among water, sediment, and valley context; and the need to broaden the natural flow regime concept. Explicitly incorporating sediment is challenging, because sediment is supplied, transported, and stored by nonlinear and episodic processes operating at different temporal and spatial scales than water and because sediment regimes have been highly altered by humans. Nevertheless, managing for a desired balance between sediment supply and transport capacity is not only tractable, given current geomorphic process knowledge, but also essential because of the importance of sediment regimes to aquatic and riparian ecosystems, the physical template of which depends on sediment-driven river structure and function.

Evaluation of Intake Efficiencies and Associated Sediment-Concentration Errors in US D-77 Bag-Type and US D-96-Type Depth-Integrating Suspended-Sediment Samplers

NASA Astrophysics Data System (ADS)

Sabol, T. A.; Topping, D. J.; Griffiths, R. E.

2011-12-01

Accurate measurements of suspended-sediment concentration require suspended-sediment samplers to operate isokinetically with an intake-efficiency of 1.0 ± 0.10. Results from 1940s Federal Interagency Sedimentation Project (FISP) laboratory experiments show that when the intake efficiency does not equal 1.0, suspended-sediment samplers either under- or oversample sediment relative to water, leading to biases in suspended-sediment concentration. The majority of recent FISP sampler development and testing has been conducted under uniform flow conditions using flume and slack-water tow tests, with little testing in actual turbulent rivers. Recent work has focused on the hydraulic characteristics and intake efficiencies of these samplers, without field investigations of the accuracy of the suspended-sediment data collected with these samplers. When depth-integrating suspended-sediment samplers are deployed under the non-uniform and turbulent conditions that exist in rivers, multiple factors may contribute to departures from isokinetic sampling. This introduces errors into the suspended-sediment data that may not be predictable on the basis of flume and tow tests alone. This study (1) evaluates the intake efficiencies of the older US D-77 bag-type and newer, FISP-approved US D-96 samplers at multiple river cross sections under a range of flow conditions; (2) examines if water temperature and sampling duration explain measured differences in intake efficiency between samplers and between laboratory and field tests; (3) models and predicts the directions and magnitudes of errors in measured suspended-sand concentration; and (4) determines if the relative differences in suspended-sediment concentration in a variety of size classes are consistent with the differences expected on the basis of the 1940s FISP-laboratory experiments. Results indicate that under river conditions, the intake efficiency of the US D-96 sampler is superior to that of the US D-77 bag-type sampler and the overall performance of the US D-96 sampler is closer to the FISP-acceptable range of isokinetic operation. These results are in contrast with FISP-conducted flume tests that show that both the US D-77 bag-type and US D-96 samplers operate isokinetically in the laboratory. Our results show that a major problem with both samplers is the large time-dependent decrease in intake efficiency that likely arises from an inability of the filling bag to displace water in the flooded sampler cavity at the rate required for isokinetic sampling. Predicted errors in suspended-sand concentration measurements made with the US D-96 sampler are much smaller than those made with the US D-77 bag-type sampler, especially when the effects of water temperature and sampling duration are taken into account. Biases in the concentrations in each size class measured using the US D-77 bag-type relative to the US D-96 samplers are as expected and consistent with the results from the 1940s FISP laboratory experiments.

Modelling geomorphic responses to human perturbations: Application to the Kander river, Switzerland

NASA Astrophysics Data System (ADS)

Ramirez, Jorge; Zischg, Andreas; Schürmann, Stefan; Zimmermann, Markus; Weingartner, Rolf; Coulthard, Tom; Keiler, Margreth

2017-04-01

Before 1714 the Kander river (Switzerland) flowed into the Aare river causing massive flooding and for this reason the Kander river was deviated (Kander correction) to lake Thun. The Kander correction was a pioneering hydrological project and induced a major human change to the landscape, but had unintended hydrological and geomorphic impacts that cascaded upstream and downstream. For example doubling the catchment area of Lake Thun, which gave rise to major flood problems, cessation of direct sediment delivery to the Aare, and sediment flux to lake Thun forming the Kander delta. More importantly the Kander correction shortened the Kander river and substantially increased the slope and bed shear of the Kander upstream from the correction. Consequently impacts of the correction cascaded upstream as a migrating knickpoint and eroded the river channel at unprecedented rates. Today we may have at our disposal the theoretical and empirical foundations to foresee the consequences of human intervention into natural systems. One method to investigate such geomorphic changes are numerical models that estimate the evolution of rivers by simulating the movement of water and sediment. Although much progress has been made in the development of these geomorphic models, few models have been tested in circumstances with rare perturbations and extreme forcings. As such, it remains uncertain if geomorphic models are useful and stable in extreme situations that include large movements of sediment and water. Here, in this study, we use historic maps and documents to develop a detailed geomorphic model of the Kander river starting in the year 1714. We use this model to simulate the extreme geomorphic events that preceded the deviation of the Kander river into Lake Thun and simulate changes to the river until conditions become relatively stable. We test our model by replicating long term impacts to the river that include 1) rates of incision within the correction, 2) knickpoint migration, and 3) delta formation in Lake Thun. In doing this we build confidence in the model and gain understanding of how the river system responded to anthropogenic perturbations.

Simulation of hydrologic conditions and suspended-sediment loads in the San Antonio River Basin downstream from San Antonio, Texas, 2000-12

USGS Publications Warehouse

Banta, J. Ryan; Ockerman, Darwin J.

2014-01-01

Suspended sediment in rivers and streams can play an important role in ecological health of rivers and estuaries and consequently is an important issue for water-resource managers. To better understand suspended-sediment loads and transport in a watershed, the U.S. Geological Survey (USGS), in cooperation with the San Antonio River Authority, developed a Hydrological Simulation Program—FORTRAN model to simulate hydrologic conditions and suspended-sediment loads during 2000–12 for four watersheds, which comprise the overall study area in the San Antonio River Basin (hereinafter referred to as the “USGS–2014 model”). The study area consists of approximately 2,150 square miles encompassing parts of Bexar, Guadalupe, Wilson, Karnes, DeWitt, Goliad, Victoria, and Refugio Counties. The USGS–2014 model was calibrated for hydrology and suspended sediment for 2006–12. Overall, model-fit statistics and graphic evaluations from the calibration and testing periods provided multiple lines of evidence indicating that the USGS–2014 model simulations of hydrologic and suspended-sediment conditions were mostly “good” to “very good.” Model simulation results indicated that approximately 1,230 tons per day of suspended sediment exited the study area and were delivered to the Guadalupe River during 2006–12, of which approximately 62 percent originated upstream from the study area. Sample data and simulated model results indicate that most of the suspended-sediment load in the study area consisted of silt- and clay-sized particles (less than 0.0625 millimeters). The Cibolo Creek watershed was the largest contributor of suspended sediment from the study area. For the entire study area, open/developed land and cropland exhibited the highest simulated soil erosion rates; however, the largest contributions of sediment (by land-cover type) were pasture and forest/rangeland/shrubland, which together composed approximately 80 percent of the land cover of the study area and generated about 70 percent of the suspended-sediment load from the study area.

Toxicity of sediment cores collected from the Ashtabula River in northeastern Ohio, USA, to the amphipod Hyalella azteca

USGS Publications Warehouse

Ingersoll, C.G.; Kemble, N.E.; Kunz, J.L.; Brumbaugh, W.G.; MacDonald, D.D.; Smorong, D.

2009-01-01

This study was conducted to support a Natural Resource Damage Assessment and Restoration project associated with the Ashtabula River in Ohio. The objective of the study was to evaluate the chemistry and toxicity of 50 sediment samples obtained from five cores collected from the Ashtabula River (10 samples/core, with each 10-cm-diameter core collected to a total depth of about 150 cm). Effects of chemicals of potential concern (COPCs) measured in the sediment samples were evaluated by measuring whole-sediment chemistry and whole-sediment toxicity in the sediment samples (including polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], organochlorine pesticides, and metals). Effects on the amphipod Hyalella azteca at the end of a 28-day sediment toxicity test were determined by comparing survival or length of amphipods in individual sediment samples in the cores to the range of responses of amphipods exposed to selected reference sediments that were also collected from the cores. Mean survival or length of amphipods was below the lower limit of the reference envelope in 56% of the sediment samples. Concentrations of total PCBs alone in some samples or concentrations of total PAHs alone in other samples were likely high enough to have caused the reduced survival or length of amphipods (i.e., concentrations of PAHs or PCBs exceeded mechanistically based and empirically based sediment quality guidelines). While elevated concentrations of ammonia in pore water may have contributed to the reduced length of amphipods, it is unlikely that the reduced length was caused solely by elevated ammonia (i.e., concentrations of ammonia were not significantly correlated with the concentrations of PCBs or PAHs and concentrations of ammonia were elevated both in the reference sediments and in the test sediments). Results of this study show that PAHs, PCBs, and ammonia are the primary COPCs that are likely causing or substantially contributing to the toxicity to sediment-dwelling organisms. ?? 2009 US Government.

Tracing the sources and cycling of phosphorus in river sediments using oxygen isotopes: Methodological adaptations and first results from a case study in France.

PubMed

Pistocchi, Chiara; Tamburini, Federica; Gruau, Gerard; Ferhi, André; Trevisan, Dominique; Dorioz, Jean-Marcel

2017-03-15

An essential aspect of eutrophication studies is to trace the ultimate origin of phosphate ions (P-PO 4 ) associated with the solid phase of river sediments, as certain processes can make these ions available for algae. However, this is not a straightforward task because of the diversity of allochthonous and autochthonous sources that can supply P-PO 4 to river sediments as well as the existence of in-stream processes that can change the speciation of these inputs and obscure the original sources. Here, we present the results of a study designed to explore the potentials, limitations and conditions for the use of the oxygen isotope composition of phosphate (δ 18 Op) extracted from river sediments for this type of tracing. We first tested if the method commonly applied to soils to purify P-PO 4 and to measure their δ 18 Op concentrations could be adapted to sediments. We then applied this method to a set of sediments collected in a river along a gradient of anthropogenic pressure and compared their isotopic signatures with those from samples that are representative of the potential P-PO 4 inputs to the river system (soils and riverbank material). The results showed that following some adaptations, the purification method could be successfully transposed to river sediments with a high level of P-PO 4 purification (>97%) and high δ 18 Op measurement repeatability and accuracy (<0.4‰). The values for the potential allochthonous sources varied from 11.8 to 18.3‰, while the δ 18 Op value for the river sediments ranged from 12.2 to 15.8‰. Moreover, a sharp increase (>3‰) in the sediment δ 18 Op value immediately downstream from the discharge point revealed the strong impact of municipal wastewater. The calculation of the theoretical equilibrium δ 18 O p values using the river water temperature and δ 18 O w showed that the downstream sediments were in equilibrium, which was not the case for the upstream sediments. This difference could be related to the contrast between the short residence time of the transfer system in the catchment head, which can preserve the isotopic variability of the source materials, and the longer residence times and higher P bioavailability in the lower catchment, possibly fostering the recycling of P-PO 4 by the biota and the equilibration of the oxygen isotope signature in P-PO 4 . These results demonstrate the potential of the isotopic approach to assess the sources and in-stream turnover of sedimentary P in river systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Polynuclear Aromatic Hydrocarbons and Toxicity of Sediments from the Elizabeth River, Hampton Roads, Virginia

DTIC Science & Technology

1984-10-01

solid phase experiment, the shrimp were exposed to high (35 ppt) or law (10 ppt) salinities for 24 hours to test osmoregulation capacities. The...of sediments from these stations are rather low. Significant osmoregulation and, to a lesser degree, respiration effects were observed during the tests

Evaluating the Effects of Constriction by Levees on a Dynamic Gravel-Bed River through Morphological Sediment Budgeting and Bed Mobility Studies, Snake River, WY

NASA Astrophysics Data System (ADS)

Leonard, C.; Legleiter, C. J.

2014-12-01

High-energy gravel-bed rivers are subject to a range of management practices used to control the system's dynamic behavior. The Snake River, near Jackson, WY, offers an opportunity to study the morphological effects of management practices through a comparison of a reach confined by levees to an unmanaged reach just upstream within Grand Teton National Park (GTNP). I hypothesize that levees have reduced sediment supply by disconnecting the river from its banks and increased transport capacity by increasing flow velocity. Together, these effects accentuate the sediment deficit in the leveed reach. To test this I am developing a morphological sediment budget from GTNP to Wilson, WY, using LiDAR data from 2007 and 2012. This analysis will yield insight as to how sediment transport varies between the relatively natural reach in GTNP and the leveed reach downstream. A problem inherent to morphological budgets is the inability to decipher when change occurs within the budget timeframe. To combat this, a partial mobility study was executed using 300 PIT tagged gravels within the leveed reach. Gravels were relocated to decipher how bed mobility and sediment transport varied with grain size under a range of hydraulic conditions. These results are then used to estimate a critical discharge representing the inception of bed motion and geomorphic change. The critical discharge will be used to reconstruct the timing of bed mobility based on streamflow records and thus deconvolve when morphological change occurred during the sediment budget period. I further hypothesize that a greater imbalance between transport capacity and sediment supply in the leveed reach causes the bed to armor, resulting in larger critical shear stresses and implying that the bed will be mobilized only during greater discharge events. To test this hypothesis I will measure armor ratios within the leveed reach and examine how bed mobility differs between the two reaches by comparing the results of our partial mobility study to a previous tracer study within GTNP.

Characterization and modeling of sediment settling, consolidation, and suspension to optimize coastal Louisiana restoration

NASA Astrophysics Data System (ADS)

Sha, X.; Xu, K.; Bentley, S. J.; Robichaux, P. A.

2018-04-01

Many research efforts have been undertaken over many decades in the field of Louisiana coastal restoration, but long-term experiments for sediment suspension and consolidation in diversion-receiving basins are still limited, despite significance of this topic to ongoing restoration strategies. Sediment samples were collected from two active diversions on the Mississippi River: West Bay, a semi-enclosed bay located on the Mississippi River Delta and fed by the West Bay Diversion, and from Big Mar pond, a receiving basin of the Caernarvon freshwater diversion from the lower Mississippi River, Louisiana, USA. A dual-core Gust Erosion Microcosm System was used to measure time-series (0.5, 1, 2, 3, 4, 5, and 6-months after initial settling) erodibility at seven shear stress regimes (0.01-0.60 Pa) using experimental cores prepared with two initial sediment concentrations (60 and 120 kg m-3). A 230-cm tall settling column with nine sampling ports was used to measure the consolidation rates for initial sediment concentrations ranging from fluid mud (10 kg m-3) to dredge effluent (120 kg m-3), in combination with two levels of salinity (1 and 5). The erodibility of West Bay sediment decreased with increasing time of consolidation. The critical shear stress for resuspension increased from 0.2 Pa after 2 months to 0.45 Pa after 4 months of consolidation. The consolidation rates were inversely and exponentially related to initial sediment concentrations. Consolidation tests in salinity of 1 generally settled faster than that in salinity of 5, and consolidation tests with low sediment concentration tests generally settled faster than high-concentration tests. An exponential coefficient was added in the Sanford (2008) model to better predict the consolidation profile of both rapid early settling and slow self-weight consolidation processes. Our study suggests that enclosed basin, low salinity, relatively low sediment concentration and minimized disturbance for 4 months all favor of mud deposition and retention, and these factors should be considered in the design of coastal restoration projects such as dredging effluent placements and sediment diversions.

Rapid formation of hyperpycnal sediment gravity currents offshore of a semi-arid California river

USGS Publications Warehouse

Warrick, J.A.; Xu, Jie; Noble, M.A.; Lee, H.J.

2008-01-01

Observations of sediment dispersal from the Santa Clara River of southern California during two moderately sized river discharge events suggest that river sediment rapidly formed a negatively buoyant (hyperpycnal) bottom plume along the seabed within hours of peak discharge. An array of acoustic and optical sensors were placed at three stations 1 km from the Santa Clara River mouth in 10-m water depth during January-February 2004. These combined observations suggest that fluid mud concentrations of suspended sediment (>10 g/l) and across-shore gravity currents (???5 cm/s) were observed in the lower 20-40 cm of the water column 4-6 h after discharge events. Gravity currents were wave dominated, rather than auto-suspending, and appeared to consist of silt-to-clay sized sediment from the river. Sediment mass balances suggest that 25-50% of the discharged river sediment was transported by these hyperpycnal currents. Sediment settling purely by flocs (???1 mm/s) cannot explain the formation of the observed hyperpycnal plumes, therefore we suggest that some enhanced sediment settling from mixing, convective instabilities, or diverging plumes occurred that would explain the formation of the gravity currents. These combined results provide field evidence that high suspended-sediment concentrations from rivers (>1 g/l) may rapidly form hyperpycnal sediment gravity currents immediately offshore of river mouths, and these pathways can explain a significant portion of the river-margin sediment budget. The fate of this sediment will be strongly influenced by bathymetry, whereas the fate of the remaining sediment will be much more influenced by ocean currents.

Development and Testing of Physically-Based Methods for Filling Gaps in Remotely Sensed River Data

DTIC Science & Technology

2011-09-30

Filling Gaps in Remotely Sensed River Data Jonathan M. Nelson US Geological Survey National Research Program Geomorphology and Sediment Transport...the research work carried out under this grant are to develop and test two methods for filling in gaps in remotely sensed river data. The first...information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215

Multiscale Modeling of Radioisotope Transfers in Watersheds, Rivers, Reservoirs and Ponds of Fukushima Prefecture

NASA Astrophysics Data System (ADS)

Zheleznyak, M.; Kivva, S.; Nanba, K.; Wakiyama, Y.; Konoplev, A.; Onda, Y.; Gallego, E.; Papush, L.; Maderych, V.

2015-12-01

The highest densities of the radioisotopes in fallout from the Fukushima Daiichi NPP in March 2011 were measured at the north eastern part of Fukushima Prefecture. The post-accidental aquatic transfer of cesium -134/137 includes multiscale processes: wash-off from the watersheds in solute and with the eroded soil, long-range transport in the rivers, deposition and resuspension of contaminated sediments in reservoirs and floodplains. The models of EU decision support system RODOS are used for predicting dynamics of 137Cs in the Fukushima surface waters and for assessing efficiency of the remediation measures. The transfer of 137Cs through the watershed of Niida River was simulated by DHSVM -R model that includes the modified code of the distributed hydrological and sediment transport model DHSVM (Lettenmayer, Wigmosta et al.) and new module of radionuclide transport. DHSMV-R was tested by modelling the wash-off from the USLE experimental plots in Fukushima prefecture. The model helps to quantify the influence of the differentiators of Fukushima and Chernobyl watersheds, - intensity of extreme precipitation and steepness of watershed, on the much higher values of the ratio "particulated cesium /soluted cesium" in Fukushima rivers than in Chernobyl rivers. Two dimensional model COASTOX and three dimensional model THREETOX are used to simulate the fate of 137Cs in water and sediments of reservoirs in the Manogawa River, Otagawa River, Mizunashigawa River, which transport 137Cs from the heavy contaminated watersheds to the populated areas at the Pacific coast. The modeling of the extreme floods generated by typhoons shows the resuspension of the bottom sediments from the heavy contaminated areas in reservoirs at the mouths of inflowing rivers at the peaks of floods and then re-deposition of 137Cs downstream in the deeper areas. The forecasts of 137Cs dynamics in bottom sediments of the reservoirs were calculated for the set of the scenarios of the sequences of the high floods of the next years. MOIRA -LAKE model of long term radioisotopes transfer in water, bottom sediment and fish was used for the assessments of the efficiency of the bottom sediment dredging for the remediation of the irrigation ponds at Okuma town.

Sediment oxygen demand in the Saddle River and Salem River watersheds, New Jersey, July-August 2008

USGS Publications Warehouse

Heckathorn, Heather A.; Gibs, Jacob

2010-01-01

Many factors, such as river depth and velocity, biochemical oxygen demand, and algal productivity, as well as sediment oxygen demand, can affect the concentration of dissolved oxygen in the water column. Measurements of sediment oxygen demand, in conjunction with those of other water-column water-quality constituents, are useful for quantifying the mechanisms that affect in-stream dissolved-oxygen concentrations. Sediment-oxygen-demand rates are also needed to develop and calibrate a water-quality model being developed for the Saddle River and Salem River Basins in New Jersey to predict dissolved-oxygen concentrations. This report documents the methods used to measure sediment oxygen demand in the Saddle River and Salem River watersheds along with the rates of sediment oxygen demand that were obtained during this investigation. In July and August 2008, sediment oxygen demand was measured in situ in the Saddle River and Salem River watersheds. In the Saddle River Basin, sediment oxygen demand was measured twice at two sites and once at a third location; in the Salem River Basin, sediment oxygen demand was measured three times at two sites and once at a third location. In situ measurements of sediment oxygen demand in the Saddle River and Salem River watersheds ranged from 0.8 to 1.4 g/m2d (grams per square meter per day) and from 0.6 to 7.1 g/m2d at 20 degrees Celsius, respectively. Except at one site in this study, rates of sediment oxygen demand generally were low. The highest rate of sediment oxygen demand measured during this investigation, 7.1 g/m2d, which occurred at Courses Landing in the Salem River Basin, may be attributable to the consumption of oxygen by a large amount of organic matter (54 grams per kilogram as organic carbon) in the streambed sediments or to potential error during data collection. In general, sediment oxygen demand increased with the concentration of organic carbon in the streambed sediments. Repeated measurements made 6 to 7 days apart at the same site locations resulted in similar values.

Conceptual model of sediment processes in the upper Yuba River watershed, Sierra Nevada, CA

USGS Publications Warehouse

Curtis, J.A.; Flint, L.E.; Alpers, Charles N.; Yarnell, S.M.

2005-01-01

This study examines the development of a conceptual model of sediment processes in the upper Yuba River watershed; and we hypothesize how components of the conceptual model may be spatially distributed using a geographical information system (GIS). The conceptual model illustrates key processes controlling sediment dynamics in the upper Yuba River watershed and was tested and revised using field measurements, aerial photography, and low elevation videography. Field reconnaissance included mass wasting and channel storage inventories, assessment of annual channel change in upland tributaries, and evaluation of the relative importance of sediment sources and transport processes. Hillslope erosion rates throughout the study area are relatively low when compared to more rapidly eroding landscapes such as the Pacific Northwest and notable hillslope sediment sources include highly erodible andesitic mudflows, serpentinized ultramafics, and unvegetated hydraulic mine pits. Mass wasting dominates surface erosion on the hillslopes; however, erosion of stored channel sediment is the primary contributor to annual sediment yield. We used GIS to spatially distribute the components of the conceptual model and created hillslope erosion potential and channel storage models. The GIS models exemplify the conceptual model in that landscapes with low potential evapotranspiration, sparse vegetation, steep slopes, erodible geology and soils, and high road densities display the greatest hillslope erosion potential and channel storage increases with increasing stream order. In-channel storage in upland tributaries impacted by hydraulic mining is an exception. Reworking of stored hydraulic mining sediment in low-order tributaries continues to elevate upper Yuba River sediment yields. Finally, we propose that spatially distributing the components of a conceptual model in a GIS framework provides a guide for developing more detailed sediment budgets or numerical models making it an inexpensive way to develop a roadmap for understanding sediment dynamics at a watershed scale.

Impact of seasonal variation on Escherichia coli concentrations in the riverbed sediments in the Apies River, South Africa.

PubMed

Abia, Akebe Luther King; Ubomba-Jaswa, Eunice; Momba, Maggy Ndombo Benteke

2015-12-15

Many South Africans living in resource-poor settings with little or no access to pipe-borne water still rely on rivers as alternative water sources for drinking and other purposes. The poor microbial quality of such water bodies calls for appropriate monitoring. However, routine monitoring only takes into consideration the microbial quality of the water column, and does not include monitoring of the riverbed sediments for microbial pollution. This study sought to investigate the microbial quality of riverbed sediments in the Apies River, Gauteng Province, South Africa, using Escherichia coli as a faecal indicator organism and to investigate the impact of seasonal variation on its abundance. Weekly samples were collected at 10 sampling sites on the Apies River between May and August 2013 (dry season) and between January and February 2014 (wet season). E. coli was enumerated using the Colilert®-18 Quanti-Tray® 2000 system. All sites tested positive for E. coli. Wastewater treatment work effluents had the highest negative impact on the river water quality. Seasonal variations had an impact on the concentration of E. coli both in water and sediments with concentrations increasing during the wet season. A strong positive correlation was observed between temperature and the E. coli concentrations. We therefore conclude that the sediments of the Apies River are heavily polluted with faecal indicator bacteria and could also harbour other microorganisms including pathogens. The release of such pathogens into the water column as a result of the resuspension of sediments due to extreme events like floods or human activities could increase the health risk of the populations using the untreated river water for recreation and other household purposes. There is therefore an urgent need to reconsider and review the current South African guidelines for water quality monitoring to include sediments, so as to protect human health and other aquatic lives. Copyright © 2015 Elsevier B.V. All rights reserved.

Distribution of heavy metals and environmental assessment of surface sediment of typical estuaries in eastern China.

PubMed

Bi, Shipu; Yang, Yuan; Xu, Chengfen; Zhang, Yong; Zhang, Xiaobo; Zhang, Xianrong

2017-08-15

Estuary sediment is a major pollutant enrichment medium and is an important biological habitat. This sediment has attracted the attention of the marine environmental scientists because it is a more stable and effective medium than water for monitoring regional environmental quality conditions and trends. Based on a large amount of measurement data, we analyzed the concentrations, distribution, and sources of seven heavy metals (As, Cd, Cr, Cu, Hg, Pb, and Zn) in the surface sediment of typical estuaries that empty into the sea in eastern China: the Liaohe River Estuary, Yellow River Estuary, Yangtze River Estuary, Minjiang River Estuary, and Pearl River Estuary. The heavy metal concentrations in the sediments vary considerably from one estuary to the next. The Liaohe River Estuary sediment contains elevated levels of Cd, Hg, and Zn. The Yellow River Estuary sediment contains elevated levels of As. The sediments in the Yangtze River and Minjiang River estuaries contain elevated levels of Cd and Cu and of Pb and Zn, respectively. The sediment in the Pearl River Estuary contains elevated levels of all seven heavy metals. We used the Nemerow index method to assess the environment quality. The heavy metal pollution in the Liaohe River and Pearl River estuaries is more severe than that in the other estuaries. Additional work indicates that the heavy metal pollution in the Liaohe River and Pearl River estuaries is caused mainly by human activity. Copyright © 2017. Published by Elsevier Ltd.

A data reconnaissance on the effect of suspended-sediment concentrations on dissolved-solids concentrations in rivers and tributaries in the Upper Colorado River Basin

USGS Publications Warehouse

Tillman, Fred D.; Anning, David W.

2014-01-01

The Colorado River is one of the most important sources of water in the western United States, supplying water to over 35 million people in the U.S. and 3 million people in Mexico. High dissolved-solids loading to the River and tributaries are derived primarily from geologic material deposited in inland seas in the mid-to-late Cretaceous Period, but this loading may be increased by human activities. High dissolved solids in the River causes substantial damages to users, primarily in reduced agricultural crop yields and corrosion. The Colorado River Basin Salinity Control Program was created to manage dissolved-solids loading to the River and has focused primarily on reducing irrigation-related loading from agricultural areas. This work presents a reconnaissance of existing data from sites in the Upper Colorado River Basin (UCRB) in order to highlight areas where suspended-sediment control measures may be useful in reducing dissolved-solids concentrations. Multiple linear regression was used on data from 164 sites in the UCRB to develop dissolved-solids models that include combinations of explanatory variables of suspended sediment, flow, and time. Results from the partial t-test, overall likelihood ratio, and partial likelihood ratio on the models were used to group the sites into categories of strong, moderate, weak, and no-evidence of a relation between suspended-sediment and dissolved-solids concentrations. Results show 68 sites have strong or moderate evidence of a relation, with drainage areas for many of these sites composed of a large percentage of clastic sedimentary rocks. These results could assist water managers in the region in directing field-scale evaluation of suspended-sediment control measures to reduce UCRB dissolved-solids loading.

The internal strength of rivers: autogenic processes in control of the sediment load (Tana River, Kenya)

NASA Astrophysics Data System (ADS)

Geeraert, Naomi; Ochieng Omengo, Fred; Tamooh, Fredrick; Paron, Paolo; Bouillon, Steven; Govers, Gerard

2014-05-01

The construction of sediment rating curves for monitoring stations is a widely used technique to budget sediment fluxes. Changes in the relationship between discharge and sediment concentrations over time are often attributed to human-induced changes in catchment characteristics, such as land use change, dam construction or soil conservation measures and many models have been developed to quantitatively link catchment characteristics and river sediment load. Conversely, changes in river sediment fluxes are often interpreted as indications of major changes in the catchment. By doing so, autogenic processes, taking place within the river channel, are overlooked despite the increasing awareness of their importance. We assessed the role of autogenic processes on the sediment load of Tana River (Kenya). The Tana river was impacted by major dam construction between 1968 and 1988, effectively blocking at least 80% of the sediment transfer from the highlands to the lower river reaches. However, a comparison of pre-dam sediment fluxes at Garissa (located 250 km downstream of the dams) with recent measurements shows that sediment fluxes have not changed significantly. This suggests that most of the sediment in the post-dam period has to originate from inside the alluvial plain of the river, as tributaries downstream of the dams are scarce and intermittent. Several observations are consistent with this hypothesis. We observed that, during the wet season, sediment concentrations rapidly increased below the dams and are not controlled by inputs from tributaries. Also, sediment concentrations were high at the beginning of the wet season, which can be attributed to channel adjustment to the higher discharges. The river sediment does not contain significant amounts of 137Cs or 210Pbxs, suggesting that sediments are not derived from topsoil erosion. Furthermore, we observed a counter clockwise hysteresis during individual events which can be explained by the fact that sediment mobilised within the river during a given event travels slower than the water. The highly dynamic behaviour of the river is further demonstrated by the rapid changes in river cross-section at Garissa and meander migration rates of several m y-1. In order to estimate a time frame for which changes in sediment inputs will be reflected in the sediment concentration at Garissa a single box model was developed. Results indicate that the effects of sediment blockage by the dams will only be visible after several hundreds to perhaps thousands of years. This clearly shows that autogenic processes are dominant in the lower Tana River and that, therefore, changes in sediment delivery cannot be detected in the sediment discharge record. More generally, understanding and interpreting the dynamics of such river systems requires that autogenic processes are correctly accounted for.

A comparative study of the flux and fate of the Mississippi and Yangtze river sediments

NASA Astrophysics Data System (ADS)

Xu, K.; Yang, S. L.

2015-03-01

Large rivers play a key role in delivering water and sediment into the global oceans. Large-river deltas and associated coastlines are important interfaces for material fluxes that have a global impact on marine processes. In this study, we compare water and sediment discharge from Mississippi and Yangtze rivers by assessing: (1) temporal variation under varying climatic and anthropogenic impacts, (2) delta response of the declining sediment discharge, and (3) deltaic lobe switching and Holocene sediment dispersal patterns on the adjacent continental shelves. Dam constructions have decreased both rivers' sediment discharge significantly, leading to shoreline retreat along the coast. The sediment dispersal of the river-dominated Mississippi Delta is localized but for the tide-dominated Yangtze Delta is more diffuse and influenced by longshore currents. Sediment declines and relative sea level rises have led to coastal erosion, endangering the coasts of both rivers.

Bed load transport and boundary roughness changes as competing causes of hysteresis in the relationship between river discharge and seismic amplitude recorded near a steep mountain stream

NASA Astrophysics Data System (ADS)

Roth, Danica L.; Finnegan, Noah J.; Brodsky, Emily E.; Rickenmann, Dieter; Turowski, Jens M.; Badoux, Alexandre; Gimbert, Florent

2017-05-01

Hysteresis in the relationship between bed load transport and river stage is a well-documented phenomenon with multiple known causes. Consequently, numerous studies have interpreted hysteresis in the relationship between seismic ground motion near rivers and some measure of flow strength (i.e., discharge or stage) as the signature of bed load transport. Here we test this hypothesis in the Erlenbach stream (Swiss Prealps) using a metric to quantitatively compare hysteresis in seismic data with hysteresis recorded by geophones attached beneath steel plates within the streambed, a well-calibrated proxy for direct sediment transport measurements. We find that while both the geophones and seismometers demonstrate hysteresis, the magnitude and direction of hysteresis are not significantly correlated between these data, indicating that the seismic signal at this site is primarily reflecting hysteresis in processes other than sediment transport. Seismic hysteresis also does not correlate significantly with the magnitude of sediment transport recorded by the geophones, contrary to previous studies' assumptions. We suggest that hydrologic sources and changes in water turbulence, for instance due to evolving boundary conditions at the bed, rather than changes in sediment transport rates, may sometimes contribute to or even dominate the hysteresis observed in seismic amplitudes near steep mountain rivers.