Bed Degradation and Sediment Export from the Missouri River after Dam Construction and River Training: Significance to Lower Mississippi River Sediment Loads

Science.gov (United States)

Blum, M. D.; Viparelli, E.; Sulaiman, Z. A.; Pettit, B. S.

2016-12-01

More than 40,000 dams have been constructed in the Mississippi River drainage basin, which has had a dramatic impact on suspended sediment load for the Mississippi delta. The most significant dams were constructed in the 1950s on the Missouri River in South Dakota, after which total suspended loads for the lower Mississippi River, some 2500 km downstream, were cut in half: gauging station data from the Missouri-Mississippi system show significant load reductions immediately after dam closure, followed by a continued downward trend since that time. The delta region is experiencing tremendous land loss in response to acceleration of global sea-level rise, and load reductions of this magnitude may place severe limits on mitigation efforts. Here we examine sediment export from the Missouri system due to bed scour. The US Army Corps of Engineers has compiled changes in river stage at constant discharge for 8 stations between the lowermost dam at Yankton, South Dakota and the Missouri-Mississippi confluence at St. Louis (a distance of 1250 river km), for the period 1930-2010, which we have updated to 2015. These data show two general reaches of significant bed degradation. The first extends from the last major dam at Yankton, South Dakota downstream 300 km to Omaha, Nebraska, where degradation in response to the dam exceeds 3 m. The second reach, with >2.5 m of degradation, occurs in and around Kansas City, Missouri, and has been attributed to river training activities. The reach between Omaha and Kansas City, as well as the lower Missouri below Kansas City, show River due to bed scour following dam construction and river training. This number equates to 20-25 million tons per year, which is sufficient to account for 30% of the total Missouri River load, and 15% of the total post-dam annual sediment load for the lower Mississippi River. For perspective, the quantity of sediment exported from the Missouri River due to bed scour is greater than the total load for all

Characterization of Suspended-Sediment Loading to and from John Redmond Reservoir, East-Central Kansas, 2007-2008

Science.gov (United States)

Lee, Casey J.; Rasmussen, Patrick P.; Ziegler, Andrew C.

2008-01-01

Storage capacity in John Redmond Reservoir is being lost to sedimentation more rapidly than in other federal impoundments in Kansas. The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, initiated a study to characterize suspended-sediment loading to and from John Redmond Reservoir from February 21, 2007, through February 21, 2008. Turbidity sensors were installed at two U.S. Geological Survey stream gages upstream (Neosho River near Americus and the Cottonwood River near Plymouth) and one stream gage downstream (Neosho River at Burlington) from the reservoir to compute continuous, real-time (15-minute) measurements of suspended-sediment concentration and loading. About 1,120,000 tons of suspended-sediment were transported to, and 100,700 tons were transported from John Redmond Reservoir during the study period. Dependent on the bulk density of sediment stored in the reservoir, 5.0 to 1.4 percent of the storage in the John Redmond conservation pool was lost during the study period, with an average deposition of 3.4 to 1.0 inches. Nearly all (98-99 percent) of the incoming sediment load was transported during 9 storms which occurred 25 to 27 percent of the time. The largest storm during the study period (peak-flow recurrence interval of about 4.6-4.9 years) transported about 37 percent of the sediment load to the reservoir. Suspended-sediment yield from the unregulated drainage area upstream from the Neosho River near Americus was 530 tons per square mile, compared to 400 tons per square mile upstream from the Cottonwood River near Plymouth. Comparison of historical (1964-78) to current (2007) sediment loading estimates indicate statistically insignificant (99 percent) decrease in sediment loading at the Neosho River at Burlington. Ninety-percent confidence intervals of streamflow-derived estimates of total sediment load were 7 to 21 times larger than turbidity-derived estimates. Results from this study can be used by natural resource

Effects of feeding and organism loading rate on PCB accumulation by Lumbriculus variegatus in sediment bioaccumulation testing

Science.gov (United States)

Sediment bioaccumulation test methods published by USEPA and ASTM in 2000 specify that the Lumbriculus variegatus, a freshwater oligochaete, should not be fed during the 28-day exposure and recommends an organism loading rate of total organic carbon in sediment to organism dry we...

The application of backpropagation neural network method to estimate the sediment loads

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Ari Gunawan Taufik

2017-01-01

Full Text Available Nearly all formulations of conventional sediment load estimation method were developed based on a review of laboratory data or data field. This approach is generally limited by local so it is only suitable for a particular river typology. From previous studies, the amount of sediment load tends to be non-linear with respect to the hydraulic parameters and parameter that accompanies sediment. The dominant parameter is turbulence, whereas turbulence flow velocity vector direction of x, y and z. They were affected by water bodies in 3D morphology of the cross section of the vertical and horizontal. This study is conducted to address the non-linear nature of the hydraulic parameter data and sediment parameter against sediment load data by applying the artificial neural network (ANN method. The method used is the backpropagation neural network (BPNN schema. This scheme used for projecting the sediment load from the hydraulic parameter data and sediment parameters that used in the conventional estimation of sediment load. The results showed that the BPNN model performs reasonably well on the conventional calculation, indicated by the stability of correlation coefficient (R and the mean square error (MSE.

Transport of phosphorus, wash load and suspended sediment in the River Varde A in southwest Jutland, Denmark

DEFF Research Database (Denmark)

Thodsen, Hans; Hasholt, Bent; Pejrup, Morten

2004-01-01

Total phosphorus (TP) concentrations, suspended sediment concentrations (SSC) and wash load have been measured at three river monitoring stations in the River Varde Angstrom system since 1998. This provides the possibility of studying the link between SSC and wash load and concentrations of TP...... at the end of a small impoundment. Transport rates at the upstream stations were 57% higher for suspended sediment and 27% higher for wash load than at the downstream station, while transport of TP was the same. This indicates that phosphorus is transported adhered to the finest grain size fractions that do...

Suspended sediment load in the tidal zone of an Indonesian river

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F. A. Buschman

2012-11-01

Full Text Available Forest clearing for reasons of timber production, open pit mining and the establishment of oil palm plantations generally results in excessively high sediment loads in tropical rivers. The increasing sediment loads pose a threat to coastal marine ecosystems, such as coral reefs. This study presents observations of suspended sediment loads in the Berau River (Kalimantan, Indonesia, which debouches into a coastal ocean that is a preeminent center of coral diversity. The Berau River is relatively small and drains a mountainous, still relatively pristine basin that receives abundant rainfall. In the tidal zone of the Berau River, flow velocity was measured over a large part of the river width using a horizontal acoustic Doppler current profiler (HADCP. Surrogate measurements of suspended sediment concentration were taken with an optical backscatter sensor (OBS. Averaged over the 6.5 weeks covered by the benchmark survey period, the suspended sediment load was estimated at 2 Mt yr⁻¹. Based on rainfall-runoff modeling though, the river discharge peak during the survey was supposed to be moderate and the yearly averaged suspended sediment load is most likely somewhat higher than 2 Mt yr⁻¹. The consequences of ongoing clearing of rainforest were explored using a plot-scale erosion model. When rainforest, which still covered 50–60% of the basin in 2007, is converted to production land, soil loss is expected to increase with a factor between 10 and 100. If this soil loss is transported seaward as suspended sediment, the increase in suspended sediment load in the Berau River would impose a severe stress on this global hotspot of coral reef diversity.

Quantifying uncertainty on sediment loads using bootstrap confidence intervals

Science.gov (United States)

Slaets, Johanna I. F.; Piepho, Hans-Peter; Schmitter, Petra; Hilger, Thomas; Cadisch, Georg

2017-01-01

Load estimates are more informative than constituent concentrations alone, as they allow quantification of on- and off-site impacts of environmental processes concerning pollutants, nutrients and sediment, such as soil fertility loss, reservoir sedimentation and irrigation channel siltation. While statistical models used to predict constituent concentrations have been developed considerably over the last few years, measures of uncertainty on constituent loads are rarely reported. Loads are the product of two predictions, constituent concentration and discharge, integrated over a time period, which does not make it straightforward to produce a standard error or a confidence interval. In this paper, a linear mixed model is used to estimate sediment concentrations. A bootstrap method is then developed that accounts for the uncertainty in the concentration and discharge predictions, allowing temporal correlation in the constituent data, and can be used when data transformations are required. The method was tested for a small watershed in Northwest Vietnam for the period 2010-2011. The results showed that confidence intervals were asymmetric, with the highest uncertainty in the upper limit, and that a load of 6262 Mg year-1 had a 95 % confidence interval of (4331, 12 267) in 2010 and a load of 5543 Mg an interval of (3593, 8975) in 2011. Additionally, the approach demonstrated that direct estimates from the data were biased downwards compared to bootstrap median estimates. These results imply that constituent loads predicted from regression-type water quality models could frequently be underestimating sediment yields and their environmental impact.

Sediment load estimation in the Mellegue catchment, Algeria

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Selmi Kaouther

2016-12-01

Full Text Available Soil erosion by water and the impact of sediment transport on lakes and streams, can seriously degrade soil and create problems for both agricultural land and water quality. The present study has been carried out to assess suspended sediment yield in Mellegue catchment, northeast of Algeria. Regression analysis was used to establish a relationship between the instantaneous water discharge (Q and the instantaneous suspended sediment concentration (C based on all recorded data and seasonal ratings for the period 1970–2003. The regression technique used in this paper involved a division of data into discharge – based classes, the mean concentrations and discharges of which are used to develop power regressions, according to single and season ratings, through log-transformation. Sediment loads estimated by stratified rating curves reduced underestimations to a range from 2 to 4%. The mean annual sediment yield during the 34 years of the study period was 589.23 t·km−2·y−1. Sediment transport is dominated by fall rainstorms accounting for 41% of the annual load. The big supply of sediment during this season confirms the intense geomorphic work by fall storms caused by high intensity rainfall and low vegetation cover.

Loads of nitrate, phosphorus, and total suspended solids from Indiana watersheds

Science.gov (United States)

Bunch, Aubrey R.

2016-01-01

Transport of excess nutrients and total suspended solids (TSS) such as sediment by freshwater systems has led to degradation of aquatic ecosystems around the world. Nutrient and TSS loads from Midwestern states to the Mississippi River are a major contributor to the Gulf of Mexico Hypoxic Zone, an area of very low dissolved oxygen concentration in the Gulf of Mexico. To better understand Indiana’s contribution of nutrients and TSS to the Mississippi River, annual loads of nitrate plus nitrite as nitrogen, total phosphorus, and TSS were calculated for nine selected watersheds in Indiana using the load estimation model, S-LOADEST. Discrete water-quality samples collected monthly by the Indiana Department of Environmental Management’s Fixed Stations Monitoring Program from 2000–2010 and concurrent discharge data from the U. S. Geological Survey streamflow gages were used to create load models. Annual nutrient and TSS loads varied across Indiana by watershed and hydrologic condition. Understanding the loads from large river sites in Indiana is important for assessing contributions of nutrients and TSS to the Mississippi River Basin and in determining the effectiveness of best management practices in the state. Additionally, evaluation of loads from smaller upstream watersheds is important to characterize improvements at the local level and to identify priorities for reduction.

Monitoring to assess progress toward meeting the Assabet River, Massachusetts, phosphorus total maximum daily load - Aquatic macrophyte biomass and sediment-phosphorus flux

Science.gov (United States)

Zimmerman, Marc J.; Qian, Yu; Yong Q., Tian

2011-01-01

In 2004, the Total Maximum Daily Load (TMDL) for Total Phosphorus in the Assabet River, Massachusetts, was approved by the U.S. Environmental Protection Agency. The goal of the TMDL was to decrease the concentrations of the nutrient phosphorus to mitigate some of the instream ecological effects of eutrophication on the river; these effects were, for the most part, direct consequences of the excessive growth of aquatic macrophytes. The primary instrument effecting lower concentrations of phosphorus was to be strict control of phosphorus releases from four major wastewatertreatment plants in Westborough, Marlborough, Hudson, and Maynard, Massachusetts. The improvements to be achieved from implementing this control were lower concentrations of total and dissolved phosphorus in the river, a 50-percent reduction in aquatic-plant biomass, a 30-percent reduction in episodes of dissolved oxygen supersaturation, no low-flow dissolved oxygen concentrations less than 5.0 milligrams per liter, and a 90-percent reduction in sediment releases of phosphorus to the overlying water. In 2007, the U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, initiated studies to evaluate conditions in the Assabet River prior to the upgrading of wastewater-treatment plants to remove more phosphorus from their effluents. The studies, completed in 2008, implemented a visual monitoring plan to evaluate the extent and biomass of the floating macrophyte Lemna minor (commonly known as lesser duckweed) in five impoundments and evaluated the potential for phosphorus flux from sediments in impounded and free-flowing reaches of the river. Hydrologically, the two study years 2007 and 2008 were quite different. In 2007, summer streamflows, although low, were higher than average, and in 2008, the flows were generally higher than in 2007. Visually, the effects of these streamflow differences on the distribution of Lemna were obvious. In 2007, large amounts of

Contribution of River Mouth Reach to Sediment Load of the Yangtze River

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C. Wang

2015-01-01

Full Text Available This paper examined the sediment gain and loss in the river mouth reach of the Yangtze River by considering sediment load from the local tributaries, erosion/accretion of the river course, impacts of sand mining, and water extraction. A quantitative estimation of the contribution of the river mouth reach to the sediment load of the Yangtze River was conducted before and after impoundment of the Three Gorges Dam (TGD in 2003. The results showed that a net sediment load loss of 1.78 million ton/yr (Mt/yr occurred from 1965 to 2002 in the study area. The contribution of this reach to the sediment discharge into the sea is not as high as what was expected before the TGD. With impoundment of the TGD, channel deposition (29.90 Mt/yr and a net sediment loss of 30.89 Mt/yr occurred in the river mouth reach from 2003 to 2012. The river mouth reach has acted as a sink but not a source of sediment since impoundment of the TGD, which has exacerbated the decrease in sediment load. Technologies should be advanced to measure changes in river channel morphology, as well as in water and sediment discharges at the river mouth reach.

Suspended sediment load in the tidal zone of an Indonesian River

NARCIS (Netherlands)

Buschman, F.A.; Hoitink, A.J.F.; Jong, S.M. de; Hoekstra, P.; Hidayat, H.; Sassi, M. G.

2012-01-01

Forest clearing for reasons of timber production, open pit mining and the establishment of oil palm plantations generally results in excessively high sediment loads in tropical rivers. The increasing sediment loads pose a threat to coastal marine ecosystems, such as coral reefs. This

Rate of Loaded Sediments in Honda Bay, Puerto Princesa City, Palawan, Philippines

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Joel Becira

2006-06-01

Full Text Available A study in Honda Bay, Puerto Princesa City, Palawan, Philippines was conducted to determine and compare the rate of loaded sediments of and among six sites in Honda Bay and during two seasons, and to discuss sedimentation rate in relation to selected environmental parameters commencing on April 2003 to November 2003.Results showed that the Babuyan River significantly contributed to the amounts of sediments being loaded to Honda Bay, Puerto Princesa City of which the amount of sediments loaded between the two sampling season and among the six sampling events had no significant difference. Sediment's color and texture affirmed the land-based activities in Babuyan and Mauyon watersheds, which eventually carried into the Bay during storm weather condition.The amount of trapped sediments in all stations is probably affected by the river's discharge capacity and the river's water velocity, although the duration sediment traps were mounted could also affect the measurement of sedimentation rate.

Suspended sediment load in the tidal zone of an Indonesian river

NARCIS (Netherlands)

Buschman, F. A.; Hoitink, A. J. F.; de Jong, S. M.; Hoekstra, P.; Hidayat, H.; Sassi, M. G.

2012-01-01

Forest clearing for reasons of timber production, open pit mining and the establishment of oil palm plantations generally results in excessively high sediment loads in tropical rivers. The increasing sediment loads pose a threat to coastal marine ecosystems, such as coral reefs. This study presents

Improved estimates of filtered total mercury loadings and total mercury concentrations of solids from potential sources to Sinclair Inlet, Kitsap County, Washington

Science.gov (United States)

Paulson, Anthony J.; Conn, Kathleen E.; DeWild, John F.

2013-01-01

. Studies of groundwater in the other two fill areas were conducted under worst-case higher high tidal conditions. A December 2011 study found that concentrations of filtered total mercury in the well in the fill area on the eastern boundary of the Bremerton naval complex were less than or equal to 11 nanograms per liter, indicating that releases from the eastern area were unlikely. In addition, concentrations of total mercury of solids were low (systems on the complex in a manner that precluded this bias confirmed that suspended-solids concentrations and total mercury concentrations of suspended solids varied considerably during pumping cycles. These new data result in revised estimates of solids loadings from the dry docks. Although most of the solids discharged by the dry docks seem to be recycled Operable Unit B Marine sediment, a total of about 3.2 metric tons of solids per year containing high concentrations of total mercury were estimated to be discharged by the two dry dock systems. A simple calculation, in which solids (from dry docks, the steam plant, and tidal flushing of the largest stormwater drain) are widely dispersed throughout Operable Unit B Marine, suggests that Bremerton naval complex solids would likely have little effect on Operable Unit B Marine sediments because of high concentrations of mercury already present in the sediment.

Temporal and spatial distributions of sediment total organic carbon in an estuary river.

Science.gov (United States)

Ouyang, Y; Zhang, J E; Ou, L-T

2006-01-01

Understanding temporal and spatial distributions of naturally occurring total organic carbon (TOC) in sediments is critical because TOC is an important feature of surface water quality. This study investigated temporal and spatial distributions of sediment TOC and its relationships to sediment contaminants in the Cedar and Ortega Rivers, Florida, USA, using three-dimensional kriging analysis and field measurement. Analysis of field data showed that large temporal changes in sediment TOC concentrations occurred in the rivers, which reflected changes in the characteristics and magnitude of inputs into the rivers during approximately the last 100 yr. The average concentration of TOC in sediments from the Cedar and Ortega Rivers was 12.7% with a maximum of 22.6% and a minimum of 2.3%. In general, more TOC accumulated at the upper 1.0 m of the sediment in the southern part of the Ortega River although the TOC sedimentation varied with locations and depths. In contrast, high concentrations of sediment contaminants, that is, total polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), were found in sediments from the Cedar River. There was no correlation between TOC and PAHs or PCBs in these river sediments. This finding is in contradiction to some other studies which reported that the sorption of hydrocarbons is highly related to the organic matter content of sediments. This discrepancy occurred because of the differences in TOC and hydrocarbon source input locations. It was found that more TOC loaded into the southern part of the Ortega River, while almost all of the hydrocarbons entered into the Cedar River. This study suggested that the locations of their input sources as well as the land use patterns should also be considered when relating hydrocarbons to sediment TOC.

Response of Vallisneria natans to Increasing Nitrogen Loading Depends on Sediment Nutrient Characteristics

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Jiao Gu

2016-11-01

Full Text Available High nitrogen (N loading may contribute to recession of submerged macrophytes in shallow lakes; yet, its influences vary depending on environmental conditions. In August 2013, we conducted a 28-day factorial-designed field mesocosm experiment in Lake Taihu at the Taihu Laboratory for Lake Ecosystem Research (TLLER to examine the effects of high N loading on the growth of Vallisneria natans in systems with contrasting sediment types. We ran the experiments with two levels of nutrient loading—present-day external nutrient loading (average P: 5 μg·L−1·day−1, N: 130 μg·L−1·day−1 and P: 5 μg·L−1·day−1, and with three times higher N loading (N: 390 μg·L−1·day−1 and used sediment with two contrasting nutrient levels. V. natans growth decreased significantly with increasing N loading, the effect being dependent, however, on the nutrient status of the sediment. In low nutrient sediment, relative growth rates, leaf biomass and root biomass decreased by 11.9%, 18.2% and 23.3%, respectively, at high rather than low N loading, while the decline was larger (44.0%, 32.7% and 41.8%, respectively when using high nutrient sediment. The larger effect in the nutrient-rich sediment may reflect an observed higher shading of phytoplankton and excess nutrient accumulation in plant tissue, though potential toxic effects of the high-nutrient sediment may also have contributed. Our study confirms the occurrence of a negative effect of increasing N loading on submerged plant growth in shallow nutrient-enriched lakes and further shows that this effect is augmented when the plants grow in nutrient-rich sediment. External N control may, therefore, help to protect or restore submerged macrophytes, especially when the sediment is enriched with nutrients and organic matter.

Partitioning of trace metals in the chemical fractions of bed-load sediments of Nahr-Ibrahim river, Lebanon

International Nuclear Information System (INIS)

Korfali, Samira I.; Davies, Brian E.

1999-01-01

Full text.Sediments are the ultimate sink of trace elements. The total metal analysis may only give information concerning possible enrichment of metals. The analysis of metal partitioning in the different chemical components of sediments (exchangeable, carbonate, easily reducible, moderately reducible, organic and residual); give a detailed information on the way in which these metals are bound to sediments, their mobilization capacity and their ability to affect water quality under different environmental conditions. The studied river basin is dominated by limestone formation, the enrichment of metals in the carbonate sediment fraction is a high probability. The objective of the study was to determine the percentage of the total metal content (Fe, Mn, Zn, Cu and Pb) in the six chemical fractions of the bed load sediments of Nahr-Ibrahim river during the dry season and verify the role of carbonate for metal sediment deposition. Bed load sediments were sampled at five locations 13Km stretch, upstream from river mouth at two dates, August and October 1996. the dried samples were sieved into three mechanical fractions (1180-250 μm, 250-75 μm and <75 μm). A sequential chemical extraction was carried on each sized sample sediment, Fe, Mn, Zn, Cu and Pb were determined on the extracts by AAS. The reported data showed that Fe in mainly in the residual fraction, Mn in the residual and carbonate fraction, Zn in the residual, carbonate and Fe oxide fraction, Cu in the residual, carbonate and organic fraction, Pb in the carbonate fraction. The carbonate fraction in sediments played the major common role for metal sediment deposition

Exploring the role of flood transience in coarse bed load sediment transport

Science.gov (United States)

Phillips, C. B.; Singer, M. B.; Hill, K. M.; Paola, C.

2015-12-01

The rate of bed load transport under steady flow is known to vary both spatially and temporally due to various hydrologic and granular phenomena. Grain size distributions and riverbed properties (packing, imbrication, etc.) are known to affect flux for a particular value of applied flow stress, while hydrology is mainly assumed to control the magnitude of the applied bed stress above the threshold for bed material entrainment. The prediction of bed load sediment transport in field settings is further complicated by the inherent transience in flood hydrology, but little is known about how such flood transience influences bed load flux over a range of applied bed stress. Here we investigate the role of flood transience for gravel bed load transport through controlled laboratory experiments in a 28 m long 0.5 meter wide flume. We explore transient flow as the combination of unsteady and intermittent flow, where unsteady flow varies in magnitude over a given duration, and intermittent flow is characterized by turning the flow on and off. We systematically vary these details of flood hydrographs from one experiment to the next, and monitor the bed load as it varies with water discharge in real time by measuring sediment flux and tracking particles. We find that even with a narrow unimodal grain size distribution and constant sediment supply we observe hysteresis in bed load flux, different thresholds for entrainment and distrainment for the rising and falling limbs of a flood, and a threshold of entrainment that can vary one flood hydrograph to the next. Despite these complex phenomena we find that the total bed load transported for each flood plots along a linear trend with the integrated excess stress, consistent with prior field results. These results suggest that while the effects of transient flow and the shape of the hydrograph are measurable, they are second-order compared to the integrated excess stress.

Environmental impact of aquaculture-sedimentation and nutrient loadings from shrimp culture of the southeast coastal region of the Bay of Bengal.

Science.gov (United States)

Das, Biplob; Khan, Yusuf Sharif Ahmed; Das, Pranab

2004-01-01

Nutrient loadings were measured for surface seawater and bottom sediments of semi-intensive and improved extensive shrimp culture pond, adjacent estuary, and fallow land in the south-east coastal region of Bangladesh during August, 2000-January, 2001 to evaluate the impact of shrimp culture. The mean levels of nutrients found in the pond surface water were 108.780 mg/L for CaCO3, 0.526 mg/L for NH4+ -N, 3.075 wt% for organic carbon, 7.00 mg/L for PO4-P, 5.57 mg/L for NO3-N, and 7.33 mg/L for chlorophyll-a. The maximum mean value of H2S (0.232 mg/L) was found in estuarine water. Nutrients loading were found to be decreased with distance from the shrimp farm discharge unit in estuarine water. The mean level of organic matter, total nitrogen, and organic carbon were found in higher concentrations in sediments of cultured pond compared to bottom soil of adjacent fallow land at the same elevation. Extractable Ca values were found in higher concentration (550.33 ppt) in adjacent fallow land, as the shrimps for molting in shrimp ponds use extractable Ca. The relation between seawater H2S value and sediment pH (r = - 0.94); sediment organic carbon and sediment pH values (r = -0.76), sediment total nitrogen and sediment pH (r = -0.74) were found to be highly negatively correlated. Whereas the relation between seawater H2S value and sediment total nitrogen (r = 0.92), water NH4+ -N and sediment pH (r = 0.66) were found to be positively correlated. The results revealed that load of nutrients at eutrophic level in estuarine water, and decrease of soil pH; leading to acid sulphate soil formation indicates a negative impact of shrimp culture.

Sediment and Fecal Indicator Bacteria Loading in a Mixed Land Use Watershed: Contributions from Suspended and Bed Load Transport

Science.gov (United States)

Water quality studies that quantify sediment and fecal bacteria loading commonly focus on suspended contaminants transported during high flows. Fecal contaminants in bed sediments are typically ignored and need to be considered because of their potential to increase pathogen load...

Historical polycyclic aromatic and petrogenic hydrocarbon loading in Northern Central Gulf of Mexico shelf sediments.

Science.gov (United States)

Overton, E B; Ashton, B M; Miles, M S

2004-10-01

The distribution of selected hydrocarbons within ten dated sediment cores taken from the Mississippi River Bight off coastal Louisiana suggests a chronic contaminant loading from several sources including the river itself, oil and gas exploration in the central Gulf of Mexico (GOM) shelf area, and natural geologic hydrocarbon seeps. Data were grouped as either total polycyclic aromatic hydrocarbons (PAH's), which were indicative of pyrogenic PAH's; or estimated total hopanes (indicative of petrogenic hydrocarbons). The total PAH concentrations and estimated total hopanes begin increasing above background levels (approximately 200 ng g(-1)) after the 1950s. The distribution of these hydrocarbons and hopanes within the dated sediment cores suggests that the Mississippi River is a regional source of pyrogenic PAH's, and that the hopanes are from natural geologic hydrocarbon seeps, oil and gas exploration in the GOM, or both.

Estimating sediment discharge: Appendix D

Science.gov (United States)

Gray, John R.; Simões, Francisco J. M.

2008-01-01

Sediment-discharge measurements usually are available on a discrete or periodic basis. However, estimates of sediment transport often are needed for unmeasured periods, such as when daily or annual sediment-discharge values are sought, or when estimates of transport rates for unmeasured or hypothetical flows are required. Selected methods for estimating suspended-sediment, bed-load, bed- material-load, and total-load discharges have been presented in some detail elsewhere in this volume. The purposes of this contribution are to present some limitations and potential pitfalls associated with obtaining and using the requisite data and equations to estimate sediment discharges and to provide guidance for selecting appropriate estimating equations. Records of sediment discharge are derived from data collected with sufficient frequency to obtain reliable estimates for the computational interval and period. Most sediment- discharge records are computed at daily or annual intervals based on periodically collected data, although some partial records represent discrete or seasonal intervals such as those for flood periods. The method used to calculate sediment- discharge records is dependent on the types and frequency of available data. Records for suspended-sediment discharge computed by methods described by Porterfield (1972) are most prevalent, in part because measurement protocols and computational techniques are well established and because suspended sediment composes the bulk of sediment dis- charges for many rivers. Discharge records for bed load, total load, or in some cases bed-material load plus wash load are less common. Reliable estimation of sediment discharges presupposes that the data on which the estimates are based are comparable and reliable. Unfortunately, data describing a selected characteristic of sediment were not necessarily derived—collected, processed, analyzed, or interpreted—in a consistent manner. For example, bed-load data collected with

An Analytic Equation Partitioning Climate Variation and Human Impacts on River Sediment Load

Science.gov (United States)

Zhang, J.; Gao, G.; Fu, B.

2017-12-01

Spatial or temporal patterns and process-based equations could co-exist in hydrologic model. Yet, existing approaches quantifying the impacts of those variables on river sediment load (RSL) changes are found to be severely limited, and new ways to evaluate the contribution of these variables are thus needed. Actually, the Newtonian modeling is hardly achievable for this process due to the limitation of both observations and knowledge of mechanisms, whereas laws based on the Darwinian approach could provide one component of a developed hydrologic model. Since that streamflow is the carrier of suspended sediment, sediment load changes are documented in changes of streamflow and suspended sediment concentration (SSC) - water discharge relationships. Consequently, an analytic equation for river sediment load changes are proposed to explicitly quantify the relative contributions of climate variation and direct human impacts on river sediment load changes. Initially, the sediment rating curve, which is of great significance in RSL changes analysis, was decomposed as probability distribution of streamflow and the corresponding SSC - water discharge relationships at equally spaced discharge classes. Furthermore, a proposed segmentation algorithm based on the fractal theory was used to decompose RSL changes attributed to these two portions. Additionally, the water balance framework was utilized and the corresponding elastic parameters were calculated. Finally, changes in climate variables (i.e. precipitation and potential evapotranspiration) and direct human impacts on river sediment load could be figured out. By data simulation, the efficiency of the segmentation algorithm was verified. The analytic equation provides a superior Darwinian approach partitioning climate and human impacts on RSL changes, as only data series of precipitation, potential evapotranspiration and SSC - water discharge are demanded.

Increasing precision of turbidity-based suspended sediment concentration and load estimates.

Science.gov (United States)

Jastram, John D; Zipper, Carl E; Zelazny, Lucian W; Hyer, Kenneth E

2010-01-01

Turbidity is an effective tool for estimating and monitoring suspended sediments in aquatic systems. Turbidity can be measured in situ remotely and at fine temporal scales as a surrogate for suspended sediment concentration (SSC), providing opportunity for a more complete record of SSC than is possible with physical sampling approaches. However, there is variability in turbidity-based SSC estimates and in sediment loadings calculated from those estimates. This study investigated the potential to improve turbidity-based SSC, and by extension the resulting sediment loading estimates, by incorporating hydrologic variables that can be monitored remotely and continuously (typically 15-min intervals) into the SSC estimation procedure. On the Roanoke River in southwestern Virginia, hydrologic stage, turbidity, and other water-quality parameters were monitored with in situ instrumentation; suspended sediments were sampled manually during elevated turbidity events; samples were analyzed for SSC and physical properties including particle-size distribution and organic C content; and rainfall was quantified by geologic source area. The study identified physical properties of the suspended-sediment samples that contribute to SSC estimation variance and hydrologic variables that explained variability of those physical properties. Results indicated that the inclusion of any of the measured physical properties in turbidity-based SSC estimation models reduces unexplained variance. Further, the use of hydrologic variables to represent these physical properties, along with turbidity, resulted in a model, relying solely on data collected remotely and continuously, that estimated SSC with less variance than a conventional turbidity-based univariate model, allowing a more precise estimate of sediment loading, Modeling results are consistent with known mechanisms governing sediment transport in hydrologic systems.

Seasonal Variations and Yearly Trend Evaluations of Sedimentation Loads: A Case Study at Chalok River, Terengganu, Malaysia

Directory of Open Access Journals (Sweden)

Aida Soraya Shamsuddin

2014-01-01

Full Text Available The aims of this study were to determine the relationship between seasonal variations (wet and dry periods on sedimentation loads and to identify the yearly trend of sedimentation loads at Chalok River, Terengganu, Malaysia from 2003 to 2008. It was found that wet and dry periods influenced the transportation of suspended sediment into the river significantly. The highest suspended sediment loads at Chalok River occurred during the wet period when the intensity of rainfall is high. Besides, the rainfall, water level, stream flow and suspended sediment loads also were analysed using Spearman correlation to identify their relationships. The results showed significant positive relationship between suspended sediment loads with rainfall (r = 0.664, p< 0.05, water level (r = 0.923, p< 0.05 and stream flow (r = 0.919, p< 0.05. Multiple linear regressions revealed 63% of high suspended sediment loads at Chalok River can be explained by rainfall, water level and stream flow. The trends of rainfall, water level, stream flow and suspended sediment loads were analysed by using Mann-Kendall trend test where the results showed that there is a significant increasing trend for suspended sediment loads but no significant increase trend for rainfall, water level and stream flow over the studied periods. It is evident that the evaluations conducted in this study are useful in providing better understanding and reliable conclusion on the basis of seasonal variations and other environmental variables that affect the sedimentations loads in the river. Such effort provides holistic information for effective and wise management policy of river basin management in the future.

Characterization of suspended solids and total phosphorus loadings from small watersheds in Wisconsin

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Danz, Mari E.; Corsi, Steven R.; Graczyk, David J.; Bannerman, Roger T.

2010-01-01

Knowledge of the daily, monthly, and yearly distribution of contaminant loadings and streamflow can be critical for the successful implementation and evaluation of water-quality management practices. Loading data for solids (suspended sediment and total suspended solids) and total phosphorus and streamflow data for 23 watersheds were summarized for four ecoregions of Wisconsin: the Driftless Area Ecoregion, the Northern Lakes and Forests Ecoregion, the North Central Hardwoods Ecoregion, and the Southeastern Wisconsin Till Plains Ecoregion. The Northern Lakes and Forests and the North Central Hardwoods Ecoregions were combined into one region for analysis due to a lack of sufficient data in each region. Urban watersheds, all located in the Southeastern Wisconsin Till Plains, were analyzed separately from rural watersheds as the Rural Southeastern Wisconsin Till Plains region and the Urban Southeastern Wisconsin Till Plains region. Results provide information on the distribution of loadings and streamflow between base flow and stormflow, the timing of loadings and streamflow throughout the year, and information regarding the number of days in which the majority of the annual loading is transported. The average contribution to annual solids loading from stormflow periods for the Driftless Area Ecoregion was 84 percent, the Northern Lakes and Forests/North Central Hardwoods region was 71 percent, the Rural Southeastern Wisconsin Till Plains region was 70 percent, and the Urban Southeastern Wisconsin Till Plains region was 90 percent. The average contributions to annual total phosphorus loading from stormflow periods were 72, 49, 61, and 76 percent for each of the respective regions. The average contributions to annual streamflow from stormflow periods are 20, 23, 31, and 50 percent for each of the respective regions. In all regions, the most substantial loading contributions for solids were in the late winter (February through March), spring (April through May), and

Impacts of Declining Mississippi River Sediment Load on Subaqueous Delta Front Sedimentation and Geomorphology

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Maloney, J. M.; Bentley, S. J.; Xu, K.; Georgiou, I. Y.; Miner, M. D.

2016-02-01

The Mississippi River delta system is undergoing unprecedented changes due to the effects of climate change and anthropogenic alterations to the river and its delta. Since the 1950s, the suspended sediment load of the Mississippi River has decreased by approximately 50% due to the construction of >50,000 dams in the Mississippi basin. The impact of this decreased sediment load has been observed in subaerial environments, but the impact on sedimentation and geomorphology of the subaqueous delta front has yet to be examined. To identify historic trends in sedimentation patterns, we compiled bathymetric datasets, including historical charts, industry and academic surveys, and NOAA data, collected between 1764 and 2009. Sedimentation rates are variable across the delta front, but are highest near the mouth of Southwest Pass, which carries the largest percentage of Mississippi River flow and sediment into the Gulf of Mexico. The progradation rate of Southwest Pass (measured at the 10 m depth contour) has slowed from 67 m/yr between 1764 and 1940 to 26 m/yr between 1940 and 1979, with evidence of further deceleration from 1979-2009. Decreased rates of progradation are also observed at South Pass and Pass A Loutre, with the 10 m contour retreating at rates >20 m/yr at both passes. Advancement of the delta front also decelerated in deeper water (15-90 m) offshore from Southwest Pass. In this area, from 1940-1979, depth contours advanced seaward 30 m/yr, but rates declined from 1979-2005. Furthermore, over the same area, the sediment accumulation rate decreased by 81% for the same period. The Mississippi River delta front appears to be entering a phase of decline, which will likely be accelerated by future upstream management practices. This decline has implications for offshore ecosystems, biogeochemical cycling, pollutant dispersal, mudflow hazard, and the continued use of the delta as an economic and population center.

Application of dimensionless sediment rating curves to predict suspended-sediment concentrations, bedload, and annual sediment loads for rivers in Minnesota

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Ellison, Christopher A.; Groten, Joel T.; Lorenz, David L.; Koller, Karl S.

2016-10-27

Consistent and reliable sediment data are needed by Federal, State, and local government agencies responsible for monitoring water quality, planning river restoration, quantifying sediment budgets, and evaluating the effectiveness of sediment reduction strategies. Heightened concerns about excessive sediment in rivers and the challenge to reduce costs and eliminate data gaps has guided Federal and State interests in pursuing alternative methods for measuring suspended and bedload sediment. Simple and dependable data collection and estimation techniques are needed to generate hydraulic and water-quality information for areas where data are unavailable or difficult to collect.The U.S. Geological Survey, in cooperation with the Minnesota Pollution Control Agency and the Minnesota Department of Natural Resources, completed a study to evaluate the use of dimensionless sediment rating curves (DSRCs) to accurately predict suspended-sediment concentrations (SSCs), bedload, and annual sediment loads for selected rivers and streams in Minnesota based on data collected during 2007 through 2013. This study included the application of DSRC models developed for a small group of streams located in the San Juan River Basin near Pagosa Springs in southwestern Colorado to rivers in Minnesota. Regionally based DSRC models for Minnesota also were developed and compared to DSRC models from Pagosa Springs, Colorado, to evaluate which model provided more accurate predictions of SSCs and bedload in Minnesota.Multiple measures of goodness-of-fit were developed to assess the effectiveness of DSRC models in predicting SSC and bedload for rivers in Minnesota. More than 600 dimensionless ratio values of SSC, bedload, and streamflow were evaluated and delineated according to Pfankuch stream stability categories of “good/fair” and “poor” to develop four Minnesota-based DSRC models. The basis for Pagosa Springs and Minnesota DSRC model effectiveness was founded on measures of goodness

Declining sediment loads from Redwood Creek and the Klamath River, north coastal California

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Randy D. Klein; Jeffrey K. Anderson

2012-01-01

River basin sediment loads are affected by several factors, with flood magnitude and watershed erosional stability playing dominant and dynamic roles. Long-term average sediment loads for northern California river basins have been computed by several researchers by several methods. However, characterizing the dynamic nature of climate and watershed stability requires...

Turbidity-controlled suspended sediment sampling for runoff-event load estimation

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Jack Lewis

1996-01-01

Abstract - For estimating suspended sediment concentration (SSC) in rivers, turbidity is generally a much better predictor than water discharge. Although it is now possible to collect continuous turbidity data even at remote sites, sediment sampling and load estimation are still conventionally based on discharge. With frequent calibration the relation of turbidity to...

Trends in suspended-sediment loads and concentrations in the Mississippi River Basin, 1950–2009

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Heimann, David C.; Sprague, Lori A.; Blevins, Dale W.

2011-01-01

Trends in loads and concentrations of suspended sediment and suspended sand generally were downward for stations within the Mississippi River Basin during the 60-, 34-, and 12-year periods analyzed. Sediment transport in the lower Mississippi River has historically been, and continues to be, most closely correlative to sediment contributions from the Missouri River, which generally carried the largest annual suspended-sediment load of the major Mississippi River subbasins. The closure of Fort Randall Dam in the upper Missouri River in 1952 was the single largest event in the recorded historical decline of suspended-sediment loads in the Mississippi River Basin. Impoundments on tributaries and sediment reductions as a result of implementation of agricultural conservation practices throughout the basin likely account for much of the remaining Mississippi River sediment transport decline. Scour of the main-stem channel downstream from the upper Missouri River impoundments is likely the largest source of suspended sand in the lower Missouri River. The Ohio River was second to the Missouri River in terms of sediment contributions, followed by the upper Mississippi and Arkansas Rivers. Declines in sediment loads and concentrations continued through the most recent analysis period (1998–2009) at available Mississippi River Basin stations. Analyses of flow-adjusted concentrations of suspended sediment indicate the recent downward temporal changes generally can be explained by corresponding decreases in streamflows.

The impact of a hydroelectric power plant on the sediment load in downstream water bodies, Svartisen, northern Norway.

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Bogen, J; Bønsnes, T E

2001-02-05

When the Svartisen hydroelectric power plant was put into operation, extensive sediment pollution was observed in the downstream fjord area. This paper discusses the impact of the power plant and the contribution from various sources of sediment. Computation of the sediment load was based on samples collected one to four times per day. Grain size distribution analyses of suspended sediments were carried out and used as input in a routing model to study the movement of sediments through the system. Suspended sediment delivered to the fjord before the power station was constructed was measured as 8360 metric tons as an annual mean for a 12-year period. During the years 1995-1996 when the power plant was operating, the total suspended load through the power station was measured as 32609 and 30254 metric tons, respectively. Grain size distribution analyses indicate a major change in the composition of the sediments from 9% clay before the power plant was operative to 50-60% clay afterwards. This change, together with the increase in sediment load, is believed to be one of the main causes of the drastic reduction in secchi depths in the fjord. The effect of the suspended sediment load on the fjord water turbidity was evaluated by co-plotting secchi depth and power station water discharge. Measurements during 1995 and 1996 showed that at the innermost of these locations the water failed to attain the minimum requirement of 2 m secchi depth. In later years secchi depths were above the specified level. In 1997 and 1998 the conditions improved. At the more distal locality, the conditions were acceptable with only a few exceptions. A routing model was applied to data acquired at a location 2 km from the power station in order to calculate the contributions from various sediment sources. This model indicated that the contribution from reservoir bed erosion dominated in 1994 but decreased significantly in 1995. Future operation of the power station will mostly take place with

Suspended-sediment loads in the lower Stillaguamish River, Snohomish County, Washington, 2014–15

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Anderson, Scott A.; Curran, Christopher A.; Grossman, Eric E.

2017-08-03

Continuous records of discharge and turbidity at a U.S. Geological Survey (USGS) streamgage in the lower Stillaguamish River were paired with discrete measurements of suspended-sediment concentration (SSC) in order to estimate suspended-sediment loads over the water years 2014 and 2015. First, relations between turbidity and SSC were developed and used to translate the continuous turbidity record into a continuous estimate of SSC. Those concentrations were then used to predict suspended-sediment loads based on the current discharge record, reported at daily intervals. Alternative methods were used to in-fill a small number of days with either missing periods of turbidity or discharge records. Uncertainties in our predictions at daily and annual time scales were estimated based on the parameter uncertainties in our turbidity-SSC regressions. Daily loads ranged from as high as 121,000 tons during a large autumn storm to as low as –56 tons, when tidal return flow moved more sediment upstream than river discharge did downstream. Annual suspended-sediment loads for both water years were close to 1.4 ± 0.2 million tons.

Identifying the Correlation between Water Quality Data and LOADEST Model Behavior in Annual Sediment Load Estimations

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Youn Shik Park

2016-08-01

Full Text Available Water quality samples are typically collected less frequently than flow since water quality sampling is costly. Load Estimator (LOADEST, provided by the United States Geological Survey, is used to predict water quality concentration (or load on days when flow data are measured so that the water quality data are sufficient for annual pollutant load estimation. However, there is a need to identify water quality data requirements for accurate pollutant load estimation. Measured daily sediment data were collected from 211 streams. Estimated annual sediment loads from LOADEST and subsampled data were compared to the measured annual sediment loads (true load. The means of flow for calibration data were correlated to model behavior. A regression equation was developed to compute the required mean of flow in calibration data to best calibrate the LOADEST regression model coefficients. LOADEST runs were performed to investigate the correlation between the mean flow in calibration data and model behaviors as daily water quality data were subsampled. LOADEST calibration data used sediment concentration data for flows suggested by the regression equation. Using the mean flow calibrated by the regression equation reduced errors in annual sediment load estimation from −39.7% to −10.8% compared to using all available data.

Get In and Get Out: Assessing Stream Sediment Loading from Short Duration Forest Harvest Operations and Rapid Haul Road Decommissioning.

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Corrigan, A.; Silins, U.; Stone, M.

2016-12-01

Best management practices (BMPs) and associated erosion control measures for mitigating sediment impacts from forestry roads and road-stream crossings are well documented. While rapid road decommissioning after forestry operations may serve to limit broader impacts on sediment production in high value headwater streams, few studies have evaluated the combined effects of accelerated harvest operations and rapid retirement of logging roads and road-stream crossings on stream sediment. The objectives of this study were to evaluate the initial impacts of these strategies on fine sediment loading and fate during a short duration harvesting operation in 3 headwater sub-catchments in the southwestern Rocky Mountains of Alberta, Canada. A multi-pronged sampling approach (ISCOs, event focused grab sampling, continuous wash load sampling, and stream bed sediment intrusion measurements) was used to measure sediment loading and deposition in streambeds upstream and downstream of road-stream bridge crossings during harvest operations (2015) and after road and bridge crossing retirement (2016). Sediment production from forestry roads was generally much lower than has been reported from other studies in similar settings. Average total suspended solids (TSS) downstream of the bridge crossings were actually lower (-3.28 g/L; -0.704 g/L) than upstream of two bridge crossings while in-stream sediment sources contributed to elevated sediment downstream of a third road-stream crossing. Minimal in stream sediment impacts from forest harvest and road-stream crossings was likely a reflection of combined factors including a) employment of erosion control BMPs to roads and bridge crossings, b) rapid decommissioning of roads and crossings to limit exposure of linear land disturbance features, and c) drier El Niño climatic conditions during the study.

Climate-scale modelling of suspended sediment load in an Alpine catchment debris flow (Rio Cordon-northeastern Italy)

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Diodato, Nazzareno; Mao, Luca; Borrelli, Pasquale; Panagos, Panos; Fiorillo, Francesco; Bellocchi, Gianni

2018-05-01

Pulsing storms and prolonged rainfall can drive hydrological damaging events in mountain regions with soil erosion and debris flow in river catchments. The paper presents a parsimonious model for estimating climate forcing on sediment loads in an Alpine catchment (Rio Cordon, northeastern Italian Alps). Hydroclimatic forcing was interpreted by the novel CliSMSSL (Climate-Scale Modelling of Suspended Sediment Load) model to estimate annual sediment loads. We used annual data on suspended-solid loads monitored at an experimental station from 1987 to 2001 and on monthly precipitation data. The quality of sediment load data was critically examined, and one outlying year was identified and removed from further analyses. This outlier revealed that our model underestimates exceptionally high sediment loads in years characterized by a severe flood event. For all other years, the CliSMSSL performed well, with a determination coefficient (R2) equal to 0.67 and a mean absolute error (MAE) of 129 Mg y-1. The calibrated model for the period 1986-2010 was used to reconstruct sediment loads in the river catchment for historical times when detailed precipitation records are not available. For the period 1810-2010, the model results indicate that the past centuries have been characterized by large interannual to interdecadal fluctuations in the conditions affecting sediment loads. This paper argues that climate-induced erosion processes in Alpine areas and their impact on environment should be given more attention in discussions about climate-driven strategies. Future work should focus on delineating the extents of these findings (e.g., at other catchments of the European Alpine belt) as well as investigating the dynamics for the formation of sediment loads.

Regime Shift Identification of Runoff and Sediment Loads in the Yellow River Basin, China

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Fei Wang

2014-10-01

Full Text Available Runoff and sediment loads have exhibited significant changes over the past six decades in the Yellow River Basin, China. The current study evaluates the changing trends and regime shifts in runoff and sediment loads at both the annual and monthly time scales. The associated spatial and temporal variations are analyzed by a sequential t-test analysis of the regime shifts (STARS approach and the “breaks for additive seasonal and trend” (BFAST model using hydrological data at eight stations from the 1950s to 2011. Both runoff and sediment loads exhibit significant declines (p < 0.05, except in the upper reaches of the river near the Tangnaihai station. The regime shifts detected by the STARS approach are not completely consistent with the results from the BFAST method. In most cases, the regime shifts occurred in 1969 and 1986, due to the construction of large reservoirs. Climate change and other human activities, such as large-scale soil and water conservation measures, can result in abrupt changes in hydrological series at some stations. The trapping effects of reservoirs not only cause regime shifts of runoff and sediment loads, but also adjust their inter-annual and seasonal distributions. Various soil and water conservation measures are responsible for the significant reduction in runoff and sediment loads in the mid-lower reaches of the Yellow River Basin. In addition, water withdrawals from both river runoff and ground water play a critical role in the changing trends in runoff and indirectly alter the sediment loads. The findings provide a good reference for the effective promotion of climate change adaptation, water resources planning and river basin management.

Analysis of Sedimentation in Wonogiri Reservoir

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Tri Joko Inti Budi Santosa

2016-01-01

Full Text Available The Wonogiri reservoir which has 730 million cubic meters of total storage, 90 square kilometers of water area, and 1260 square kilometers of catchment area, is located in the Wonogiri Regency, Central Java Province. It was first established in 1981 and began its operation in 1982 with the expectation that it would last for about 100 years. Today (2002 the reservoir has got a serious problem of sedimentation. The sedimentation is so large that it would decrease the capacity storage of the reservoir and would shorten the length of operation. Therefore, it is necessary to predict the sediment that comes into the reservoir. This research would be based on the total sediment calculation of the sedimentation, through some methods, such as echo sounding measured data, land erosion (USLE, the calculation of the sediment in rivers. This research calculates the sediment capacities based on the water flow data and the sediment rating curves in rivers of Keduang, Tirtomoyo, Temon, upstream reach of Bengawan Solo, Alang, and Wuryantoro. The suspended load was calculated based on the sediment rating curves, whereas the bed load was computed as the percentage of the suspended load. The sum of both calculation results would be the total sediment. The calculation result showed that the total sediment which has come into the reservoir is 6.68 million cubic meters per year. As a comparison, the writer noted that the former researcher using echo sounding method done by the Faculty of Geography of the Universitas Gadjah Mada in 1985, it found that the total sediment capacity which came into the reservoir was 6.60 million cubic meters per year or 5.40 mm per year of sheet erosion. The other research using echo sounding method done by JICA in 2000 found that the total sediment which had come into the reservoir was 4.50 million cubic meters per year or 3.50 mm per year of sheet erosion. By knowing the results of calculation of the total sediment, we can learn that

Sediment load trends in the Magdalena River basin (1980-2010): Anthropogenic and climate-induced causes

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Restrepo, Juan D.; Escobar, Heber A.

2018-02-01

The Colombian Andes and its main river basin, the Magdalena, have witnessed dramatic changes in land cover and further forest loss during the last three decades. For the Magdalena River, human activities appear to have played a more prominent role compared to rainfall (climate change) to mobilize sediment. However, environmental authorities in Colombia argue that climate change is the main trigger of erosion and floods experienced during the last decade. Here we present the first regional exercise addressing the following: (1) what are the observed trends of sediment load in the northern Andes during the last three decades? and (2) are sediment load trends in agreement with tendencies in land use change and climate (e.g., precipitation)? We perform Mann-Kendall tests on sediment load series for 21 main tributary systems during the 1980-2010 period. These gauging stations represent 77% of the whole Magdalena basin area. The last decade has been a period of increased pulses in sediment transport as seen by the statistical significant trends in load. Overall, six subcatchments, representing 55% of the analyzed Magdalena basin area, have witnessed increasing trends in sediment load. Also, some major tributaries have experienced changes in their interannual mean sediment flux during the mid- 1990s and 2005. Further analysis of land cover change (e.g., deforestation) indicates that the basin has undergone considerable change. Forest cover decreased by 40% over the period of study, while the area under agriculture and pasture cover (agricultural lands 1 and 2) increased by 65%. The highest peak of forest loss on record in the Magdalena basin, 5106 km2 or 24% of the combined deforestation in Colombia, occurred during the 2005-2010 period. In contrast, Mann-Kendall tests on rainfall series for 61 stations reveal that precipitation shows no regional signs of increasing trends. Also, increasing trends in sediment load match quite well with the marked increase in forest

Continuous measurements of suspended sediment loads using dual frequency acoustic Doppler profile signals

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Antonini, Alessandro; Guerrero, Massimo; Rüther, Nils; Stokseth, Siri

2016-04-01

A huge thread to Hydropower plants (HPP) is incoming sediments in suspension from the rivers upstream. The sediments settle in the reservoir and reduce the effective head as well as the volume and reduce consequently the lifetime of the reservoir. In addition are the fine sediments causing severe damages to turbines and infrastructure of a HPP. For estimating the amount of in-coming sediments in suspension and the consequent planning of efficient counter measures, it is essential to monitor the rivers within the catchment of the HPP for suspended sediments. This work is considerably time consuming and requires highly educated personnel and is therefore expensive. Surrogate-indirect methods using acoustic and optic devices have bee developed since the last decades that may be efficiently applied for the continuous monitoring of suspended sediment loads. The presented study proposes therefore to establish a research station at a cross section of a river which is the main tributary to a reservoir of a HPP and equip this station with surrogate as well as with common method of measuring suspended load concentrations and related flow discharge and level. The logger at the research station delivers data automatically to a server. Therefore it is ensured that also large flood events are covered. Data during flood are of high interest to the HPP planners since they carried the most part of the sediment load in a hydrological year. Theses peaks can hardly be measured with common measurement methods. Preliminary results of the wet season 2015/2016 are presented. The data gives insight in the applicable range, in terms of scattering particles concentration-average size and corresponding flow discharge and level, eventually enabling the study of suspended sediment load-water flow correlations during peak events. This work is carried out as part of a larger research project on sustainable hydro power plants exposed to high sediment yield, SediPASS. SediPASS is funded by the

USING ARTIFICIAL NEURAL NETWORKS (ANNs FOR SEDIMENT LOAD FORECASTING OF TALKHEROOD RIVER MOUTH

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Vahid Nourani

2009-01-01

Full Text Available Without a doubt the carried sediment load by a river is the most important factor in creating and formation of the related Delta in the river mouth. Therefore, accurate forecasting of the river sediment load can play a significant role for study on the river Delta. However considering the complexity and non-linearity of the phenomenon, the classic experimental or physical-based approaches usually could not handle the problem so well. In this paper, Artificial Neural Network (ANN as a non-linear black box interpolator tool is used for modeling suspended sediment load which discharges to the Talkherood river mouth, located in northern west Iran. For this purpose, observed time series of water discharge at current and previous time steps are used as the model input neurons and the model output neuron will be the forecasted sediment load at the current time step. In this way, various schemes of the ANN approach are examined in order to achieve the best network as well as the best architecture of the model. The obtained results are also compared with the results of two other classic methods (i.e., linear regression and rating curve methods in order to approve the efficiency and ability of the proposed method.

Concentrations, loads, and yields of nutrients and suspended sediment in the South Pacolet, North Pacolet, and Pacolet Rivers, northern South Carolina and southwestern North Carolina, October 2005 to September 2009

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Journey, Celeste A.; Caldwell, Andral W.; Feaster, Toby D.; Petkewich, Mattew D.; Bradley, Paul M.

2011-01-01

The U.S. Geological Survey, in cooperation with Spartanburg Water, evaluated the concentrations, loads, and yields of suspended sediment, dissolved ammonia, dissolved nitrate plus nitrite, total organic nitrogen, total nitrogen, dissolved orthophosphate, dissolved phosphorus, and total phosphorus at sites in the South Pacolet, North Pacolet, and Pacolet Rivers in northern South Carolina and southwestern North Carolina from October 1, 2005, to September 30, 2009 (water years 2006 to 2009). Nutrient and sediment loads and yields also were computed for the intervening subbasin of the Pacolet River not represented by the South and North Pacolet River Basins. Except for a few outliers, the majority of the measurements of total nitrogen concentrations were well below the U.S. Environmental Protection Agency recommended guideline of 0.69 milligram per liter for streams and rivers in the nutrient ecoregion IX, which includes the study area within the Pacolet River Basin. Dissolved orthophosphate, dissolved phosphorus, and total phosphorus concentrations were significantly lower at the South Pacolet River site compared to the North Pacolet and Pacolet River sites. About 90 percent of the total phosphorus concentrations at the South Pacolet River site were below the U.S. Environmental Protection Agency recommended guideline of 0.37 milligram per liter, and more than 75 percent of the total phosphorus concentrations at the North Pacolet and Pacolet River sites were above that guideline. At all sites, minimum annual nutrient loads for the estimation period were observed during water year 2008 when severe drought conditions were present. An estimated mean annual total nitrogen load of 37,770 kilograms per year and yield of 2.63 kilograms per hectare per year were determined for the South Pacolet River site for the estimation period. The North Pacolet River site had a mean annual total nitrogen load of 65,890 kilograms per year and yield of 2.19 kilograms per hectare per year

A novel method for sampling the suspended sediment load in the tidal environment using bi-directional time-integrated mass-flux sediment (TIMS) samplers

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Elliott, Emily A.; Monbureau, Elaine; Walters, Glenn W.; Elliott, Mark A.; McKee, Brent A.; Rodriguez, Antonio B.

2017-12-01

Identifying the source and abundance of sediment transported within tidal creeks is essential for studying the connectivity between coastal watersheds and estuaries. The fine-grained suspended sediment load (SSL) makes up a substantial portion of the total sediment load carried within an estuarine system and efficient sampling of the SSL is critical to our understanding of nutrient and contaminant transport, anthropogenic influence, and the effects of climate. Unfortunately, traditional methods of sampling the SSL, including instantaneous measurements and automatic samplers, can be labor intensive, expensive and often yield insufficient mass for comprehensive geochemical analysis. In estuaries this issue is even more pronounced due to bi-directional tidal flow. This study tests the efficacy of a time-integrated mass sediment sampler (TIMS) design, originally developed for uni-directional flow within the fluvial environment, modified in this work for implementation the tidal environment under bi-directional flow conditions. Our new TIMS design utilizes an 'L' shaped outflow tube to prevent backflow, and when deployed in mirrored pairs, each sampler collects sediment uniquely in one direction of tidal flow. Laboratory flume experiments using dye and particle image velocimetry (PIV) were used to characterize the flow within the sampler, specifically, to quantify the settling velocities and identify stagnation points. Further laboratory tests of sediment indicate that bidirectional TIMS capture up to 96% of incoming SSL across a range of flow velocities (0.3-0.6 m s-1). The modified TIMS design was tested in the field at two distinct sampling locations within the tidal zone. Single-time point suspended sediment samples were collected at high and low tide and compared to time-integrated suspended sediment samples collected by the bi-directional TIMS over the same four-day period. Particle-size composition from the bi-directional TIMS were representative of the array of

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

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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 (PYangtze 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.

Temporal variability in the suspended sediment load and streamflow of the Doce River

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Oliveira, Kyssyanne Samihra Santos; Quaresma, Valéria da Silva

2017-10-01

Long-term records of streamflow and suspended sediment load provide a better understanding of the evolution of a river mouth, and its adjacent waters and a support for mitigation programs associated with extreme events and engineering projects. The aim of this study is to investigate the temporal variability in the suspended sediment load and streamflow of the Doce River to the Atlantic Ocean, between 1990 and 2013. Streamflow and suspended sediment load were analyzed at the daily, seasonal, and interannual scales. The results showed that at the daily scale, Doce River flood events are due to high intensity and short duration rainfalls, which means that there is a flashy response to rainfall. At the monthly and season scales, approximately 94% of the suspended sediment supply occurs during the wet season. Extreme hydrological events are important for the interannual scale for Doce River sediment supply to the Atlantic Ocean. The results suggest that a summation of anthropogenic interferences (deforestation, urbanization and soil degradation) led to an increase of extreme hydrological events. The findings of this study shows the importance of understanding the typical behavior of the Doce River, allowing the detection of extreme hydrological conditions, its causes and possible environmental and social consequences.

Computing time-series suspended-sediment concentrations and loads from in-stream turbidity-sensor and streamflow data

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Rasmussen, Patrick P.; Gray, John R.; Glysson, G. Doug; Ziegler, Andrew C.

2010-01-01

Over the last decade, use of a method for computing suspended-sediment concentration and loads using turbidity sensors—primarily nephelometry, but also optical backscatter—has proliferated. Because an in- itu turbidity sensor is capa le of measuring turbidity instantaneously, a turbidity time series can be recorded and related directly to time-varying suspended-sediment concentrations. Depending on the suspended-sediment characteristics of the measurement site, this method can be more reliable and, in many cases, a more accurate means for computing suspended-sediment concentrations and loads than traditional U.S. Geological Survey computational methods. Guidelines and procedures for estimating time s ries of suspended-sediment concentration and loading as a function of turbidity and streamflow data have been published in a U.S. Geological Survey Techniques and Methods Report, Book 3, Chapter C4. This paper is a summary of these guidelines and discusses some of the concepts, s atistical procedures, and techniques used to maintain a multiyear suspended sediment time series.

Sediment and Hydraulic Measurements with Computed Bed Load on the Missouri River, Sioux City to Hermann, 2014

Science.gov (United States)

2017-05-01

ER D C /C HL T R- 17 -8 Sediment and Hydraulic Measurements with Computed Bed Load on the Missouri River , Sioux City to Hermann, 2014...Hydraulic Measurements with Computed Bed Load on the Missouri River , Sioux City to Hermann, 2014 David Abraham, Marielys Ramos-Villanueva, Thad Pratt...Engineers, Omaha and Kansas City Districts, in quantifying sediment bed load and suspended load at several sites on the Missouri River for the

Near-Bed Monitoring of Suspended Sediment during a Major Flood Event Highlights Deficiencies in Existing Event-Loading Estimates

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Alistair Grinham

2018-01-01

Full Text Available Rates of fluvial sediment discharge are notoriously difficult to quantify, particularly during major flood events. Measurements are typically undertaken using event stations requiring large capital investment, and the high cost tends to reduce the spatial coverage of monitoring sites. This study aimed to characterise the near-bed suspended sediment dynamics during a major flood event using a low-cost approach. Monitoring nodes consisted of a total suspended sediment (TSS logger, a single stage sampler, and a time-lapse camera for a total cost of less than US$420. Seven nodes were deployed across an elevation gradient on the stream bank of Laidley Creek, Queensland, Australia, and two of these nodes successfully characterised the near-bed suspended sediment dynamics across a major flood event. Near-bed TSS concentrations were closely related to stream flow, with the contribution of suspended bed material dominating the total suspended load during peak flows. Observed TSS concentrations were orders of magnitude higher than historical monitoring data for this site collected using the State government event station. This difference was attributed to the event station pump inlet screening the suspended bed material prior to sample collection. The ‘first flush’ phenomenon was detected and attributed to a local resuspension of muddy crusts immediately upstream of the study site. This low-cost approach will provide an important addition to the existing monitoring of fluvial sediment discharge during flood events.

The effects of Hurricane Hugo on suspended-sediment loads, Lago Loiza Basin, Puerto Rico

Science.gov (United States)

Gellis, A.

1993-01-01

In the two main tributaries that enter Lago Loiza, Rio Grande de Loiza and Rio Gurabo, 99 600 tonnes of suspended sediment was transported by 58.2??106 m3 of runoff in a 48 h period. The storm-average suspended-sediment concentration in the Rio Grande de Loiza for Hurricane Hugo was 2290 mgl-1, the second lowest for the 12 storms that have been monitored at this site. In Rio Gurabo the storm-average suspended-sediment concentration was 1420 mg l -1, the sixth lowest recorded out of 15 monitored storms. In Quebrada Salvatierra, a small tributary to Rio Grande de Loiza, suspended-sediment concentrations were as low as 33 mg l-1 during peak runoff of 20m3s-1. Normally the suspended-sediment concentrations at this discharge are 300 mg l-1. Hurricane force winds seem to be the most important factor contributing to the lower than expected suspended-sediment loads. High winds caused vegetation and debris to be dislodged and displaced. Debris accumulated on hillslopes and in small channels, blocked bridges and formed debris dams. These dams caused local backwater effects that reduced stream velocities and decreased suspended-sediment loads. -from Author

Contemporary and historical trace metal loadings to the sediments of four lakes of the Lake Washington drainage. Completion report

International Nuclear Information System (INIS)

Spyridakis, D.E.; Barnes, R.S.

1978-01-01

Contemporary and historical loadings of lead, zinc, and copper to the profundal sediments of Lakes Washington, Sammamish, Chester Morse, and Findley were determined using chemical analysis and 210 Pb dating of sediment cores. Elemental sedimentation rates, a cross product of the sedimentation rate, and sediment concentration of a given element, were corrected for natural background concentrations and rates, and extrapolated across established sediment accumulating areas to give a conservative estimate of the pollutional trace metal loadings to each lake. The resulting chronological loadings appeared consistent with the known cultural history of the individual watersheds. Substantial alterations in sedimentation rates were noted in all lakes where deforestation, road building, suburbanization or urbanization had occurred in the lake's watershed. The quantities, elemental ratios and pollutional histories of copper, lead and zinc in the lake sediments indicate that aeolian inputs are the dominant source of trace metal pollution to the lake sediments at the present time

Variability and Trend Detection in the Sediment Load of the Upper Indus River

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Sardar Ateeq-Ur-Rehman

2017-12-01

Full Text Available Water reservoirs planned or constructed to meet the burgeoning energy and irrigation demands in Pakistan face a significant loss of storage capacity due to heavy sediment load from the upper Indus basin (UIB. Given their importance and the huge investment, assessments of current UIB sediment load and possible future changes are crucial for informed decisions on planning of optimal dams’ operation and ensuring their prolonged lifespan. In this regard, the daily suspended sediment loads (SSLs and their changes are analyzed for the meltwater-dominated zone up to the Partab Bridge and the whole UIB up to Besham Qila, which is additionally influenced by monsoonal rainfall. The gaps between intermittent suspended sediment concentration (SSC samples are filled by wavelet neural networks (WA-ANNs using discharges for each site. The temporal dynamics of SSLs and discharges are analyzed using a suite of three non-parametric trend tests while the slope is identified using Sen’s slope estimator. We found disproportional spatio-temporal trends between SSLs and discharges caused primarily by intra-annual shifts in flows, which can lead to increased trap efficiency in planned reservoirs, especially upstream of Besham Qila. Moreover, a discernible increase in SSLs recorded at Partab Bridge during summer is being deposited downstream in the river channel. This is due to a decrease in river transport capacity in the monsoonal zone. These findings will not only help to identify these morphological problems, but also accurately anticipate the spatio-temporal changes in the sediment budget of the upper Indus River. Our results will help improve reservoir operational rules and sediment management strategies for existing and 30,000-MW planned dams in the UIB.

Combining caesium-137 measurements and suspended sediment load data to investigate the sediment response of a small catchment in southern Italy

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P. Porto

2015-03-01

Full Text Available A long-term measurement programme was operated in southern Italy during the 1960s and 1970s, to provide information on the suspended sediment yields from the main river basins. Information obtained for the rivers of Calabria suggests that suspended sediment yields in this area are relatively low. However, there is evidence that the intensity of land degradation within the upstream catchments is substantially higher than suggested by the values of specific sediment yield and there is a need to explore the relationship between on-site soil loss and downstream sediment yield more closely. Monitoring time-integrated erosion rates over large areas has traditionally required extensive long-term measurement programmes employing experimental plots. The fallout radionuclide caesium-137 (137Cs offers an alternative means of documenting medium-term rates of soil loss. This paper describes the use of 137Cs measurements and the available sediment load data to explore the links between soil erosion, sediment redistribution and storage, and sediment output for a medium-scale (41.3 km2 catchment in Calabria. Data available from a sediment load monitoring programme undertaken at the catchment outlet during 1962–1977 have been used to estimate the longer-term catchment sediment yield. This estimate has been combined with information provided by the 137Cs measurements, to establish a medium-term sediment budget for the catchment. The results provided by the 137Cs measurements indicate that the catchment is subject to much higher rates of soil loss and land degradation than suggested by its specific sediment yield. These findings are consistent with the results obtained for other catchments in Calabria for which both 137Cs derived erosion rates and measured sediment yields are available.

Phosphorus and suspended sediment load estimates for the Lower Boise River, Idaho, 1994-2002

Science.gov (United States)

Donato, Mary M.; MacCoy, Dorene E.

2004-01-01

The U.S. Geological Survey used LOADEST, newly developed load estimation software, to develop regression equations and estimate loads of total phosphorus (TP), dissolved orthophosphorus (OP), and suspended sediment (SS) from January 1994 through September 2002 at four sites on the lower Boise River: Boise River below Diversion Dam near Boise, Boise River at Glenwood Bridge at Boise, Boise River near Middleton, and Boise River near Parma. The objective was to help the Idaho Department of Environmental Quality develop and implement total maximum daily loads (TMDLs) by providing spatial and temporal resolution for phosphorus and sediment loads and enabling load estimates made by mass balance calculations to be refined and validated. Regression models for TP and OP generally were well fit on the basis of regression coefficients of determination (R2), but results varied in quality from site to site. The TP and OP results for Glenwood probably were affected by the upstream wastewater-treatment plant outlet, which provides a variable phosphorus input that is unrelated to river discharge. Regression models for SS generally were statistically well fit. Regression models for Middleton for all constituents, although statistically acceptable, were of limited usefulness because sparse and intermittent discharge data at that site caused many gaps in the resulting estimates. Although the models successfully simulated measured loads under predominant flow conditions, errors in TP and SS estimates at Middleton and in TP estimates at Parma were larger during high- and low-flow conditions. This shortcoming might be improved if additional concentration data for a wider range of flow conditions were available for calibrating the model. The average estimated daily TP load ranged from less than 250 pounds per day (lb/d) at Diversion to nearly 2,200 lb/d at Parma. Estimated TP loads at all four sites displayed cyclical variations coinciding with seasonal fluctuations in discharge

Data Used in Analyses of Trends, and Nutrient and Suspended-Sediment Loads for Streams in the Southeastern United States, 1973-2005

Science.gov (United States)

Staub, Erik L.; Peak, Kelly L.; Tighe, Kirsten C.; Sadorf, Eric M.; Harned, Douglas A.

2010-01-01

Water-quality data from selected surface-water monitoring sites in the Southeastern United States were assessed for trends in concentrations of nutrients, suspended sediment, and major constituents and for in-stream nutrient and suspended-sediment loads for the period 1973-2005. The area of interest includes river basins draining into the southern Atlantic Ocean, the Gulf of Mexico, and the Tennessee River-drainage basins in Hydrologic Regions 03 (South Atlantic - Gulf) and 06 (Tennessee). This data assessment is related to studies of several major river basins as part of the U.S. Geological Survey National Water-Quality Assessment Program, which was designed to assess national water-quality trends during a common time period (1993-2004). Included in this report are data on which trend tests could be performed from 44 U.S. Geological Survey National Water Information System (NWIS) sampling sites. The constituents examined include major ions, nutrients, and suspended sediment; the physical properties examined include pH, specific conductance, dissolved oxygen, and streamflow. Also included are data that were tested for trends from an additional 290 sites from the U.S. Environmental Protection Agency Storage and Retrieval (STORET) database. The trend analyses of the STORET data were limited to total nitrogen and total phosphorus concentrations. Data from 48 U.S. Geological Survey NWIS sampling sites with sufficient water-quality and continuous streamflow data for estimating nutrient and sediment loads are included. The methods of data compilation and modification used prior to performing trend tests and load estimation are described. Results of the seasonal Kendall trend test and the Tobit trend test are given for the 334 monitoring sites, and in-stream load estimates are given for the 48 monitoring sites. Basin characteristics are provided, including regional landscape variables and agricultural nutrient sources (annual variations in cropping and fertilizer use

Annual suspended-sediment loads in the Colorado River near Cisco, Utah, 1930-82

Science.gov (United States)

Thompson, K.R.

1985-01-01

The Colorado River upstream of gaging station 09180500 near Cisco, Utah, drains about 24,100 square miles in Utah and Colorado. Altitudes in the basin range from 12,480 feet near the headwaters to 4,090 feet at station 09180500. The average annual precipitation for 1894-1982 near the station was 7.94 inches. The average annual precipitation near the headwaters often exceeds 50 inches. Rocks ranging in age from Precambrian to Holocene are exposed in the drainage basin upstream from station 09180500. Shale, limestone, siltstone, mudstone, and sandstone probably are the most easily eroded rocks in the basin, and they contribute large quantities of sediment to the Colorado River. During 1930-82, the U.S. Geological Survey collected records of fluvial sediment at station 09180500. Based on these records, the mean annual suspended-sediment load was 11,390,000 tone, ranging from 2,038,000 tons in water year 1981 to 35,700,000 tons in water year 1938. The minimum daily load of 14 tons was on August 22, 1960, and the maximum daily load of 2,790,000 tons was on October 14, 1941. (USGS)

Contaminatiom of sediment loads of the Waterwork Ružín I. by heavy metals in relation to mining sludge basins

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Brehuv Ján

2000-09-01

Full Text Available From the results of monitoring of the quality of surface water in the Hnilec and Hornád rivers and their tributaries followed that in addition to industrial toxic substances, it were the heavy metals from localities of former and still continuing mining, treatment or metallurgic activities that significantly influence a long-term polution. The subsequent project showed a need to monitor the impact of anthropogenic activity, namely on the Waterwork (VD Ružín I. It was a task of our institution to judge the quality of sediment loads in the waterwork area.The first samples of sediment loads of the waterwork were taken in 1994. The sampling process then continued on the same places in following years. The special methods of sampling of sediment loads (sediments from the waterwork bed were worked out depending on the locality of sampling. The total analysis of obtained air-dried samples was caried out using the AAS method. The heavy metals were also analysed. In the consent with standards and requiremnts of the co-ordinator of task, the sediment deposits were assessed in consent with Decree of the Ministry of Land Managment of the Slovak Republik 531/1994-540 on the highest admissible values of harmful subsatances in land.Comparing the results of sampling we have observed that the critical values have been achieved in case of Cu. Its high values were found in the branches of Hnilec and Hornád rivers, as well sa in the branch of Opátka. The increased contents of Co are in Beliansky and Opatsky branches, at the inflow of Hnilec and Folkmarsky brook into the waterwork. The position of Hg is interesting, as it was the main contaminating element of The Hornad river and its sediments in the past. Hg is not currently present at significant quantities.The vertical sampling was also carried out in the course of research. It was proved that the content of contaminating elements in sediments of waterwork originates in the industrial activity perfomed 15

Linkage between speciation of Cd in mangrove sediment and its bioaccumulation in total soft tissue of oyster from the west coast of India.

Science.gov (United States)

Chakraborty, Parthasarathi; Ramteke, Darwin; Gadi, Subhadra Devi; Bardhan, Pratirupa

2016-05-15

This study established a mechanistic linkage between Cd speciation and bioavailability in mangrove system from the west coast of India. High bioaccumulation of Cd was found in the oyster (Crassostrea sp.) even at low Cd loading in the bottom sediment. Bioaccumulation of Cd in the oyster gradually increased with the increasing concentrations of water soluble, exchangeable and carbonate/bicarbonate forms of Cd in the sediments. Fe/Mn oxyhydroxide phase was found to control Cd bioavailability in the sediment system. Cd-associated with sedimentary organic matter was bioavailable and organic ligands in the sediments were poor chelating agents for Cd. This study suggests that bioaccumulation of Cd in oyster (Crassostrea sp.) depends not on the total Cd concentration but on the speciation of Cd in the system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dramatic decreases in runoff and sediment load in the Huangfuchuan Basin of the Middle Yellow River, China: historical records and future projections

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LI, E.; Li, D.; Wang, Y.; Fu, X.

2017-12-01

The Yellow River is well known for its high sediment load and serious water shortage. The long-term averaged sediment load is about 1.6´103 million tons per year, resulting in aggrading and perched lower reaches. In recent years, however, dramatic decreases in runoff and sediment load have been observed. The annual sediment load has been less than 150 million tons in the last ten years. Extrapolation of this trend into the future would motivate substantial change in the management strategies of the Lower Yellow River. To understand the possible trend and its coevolving drivers, we performed a case study of the Huangfuchuang River, which is a tributary to the Middle Yellow River, with a drainage area of 3246 km2 and an annual precipitation of 365 mm. Statistical analysis of historical data from 1960s to 2015 showed a significantly decreasing trend in runoff and sediment load since 1984. As potential drivers, the precipitation does not show an obvious change in annual amount, while the vegetation cover and the number of check dams have been increased gradually as a result of the national Grain for Green project. A simulation with the Soil and Water Assessment Tool (SWAT) reproduced the historical evolution processes, and showed that human activities dominated the reduction in runoff and sediment load, with a contribution of around 80%. We then projected the runoff and sediment load for the next 50 years (2016-2066), considering typical scenarios of climate change and accounting for vegetation cover development subject to climate conditions and storage capacity loss of check dams due to sediment deposition. The differences between the projected trend and the historical record were analyzed, so as to highlight the coevolving processes of climate, vegetation, and check dam retention on a time scale of decades. Keywords: Huangfuchuan River Basin, sediment load, vegetation cover, check dams, annual precipitation, SWAT.

Multiple stressor effects on marine infauna: responses of estuarine taxa and functional traits to sedimentation, nutrient and metal loading

KAUST Repository

Ellis, Joanne

2017-09-14

Sedimentation, nutrients and metal loading to coastal environments are increasing, associated with urbanization and global warming, hence there is a growing need to predict ecological responses to such change. Using a regression technique we predicted how maximum abundance of 20 macrobenthic taxa and 22 functional traits separately and interactively responded to these key stressors. The abundance of most taxa declined in response to sedimentation and metal loading while a unimodal response was often associated with nutrient loading. Optimum abundances for both taxa and traits occurred at relatively low stressor levels, highlighting the vulnerability of estuaries to increasing stressor loads. Individual taxa were more susceptible to stress than traits, suggesting that functional traits may be less sensitive for detecting changes in ecosystem health. Multiplicative effects were more common than additive interactions. The observed sensitivity of most taxa to increasing sedimentation and metal loading and the documented interaction effects between multiple stressors have important implications for understanding and managing the ecological consequences of eutrophication, sedimentation and contaminants on coastal ecosystems.

Variations of Runoff and Sediment Load in the Middle and Lower Reaches of the Yangtze River, China (1950-2013).

Science.gov (United States)

Li, Na; Wang, Lachun; Zeng, Chunfen; Wang, Dong; Liu, Dengfeng; Wu, Xutong

2016-01-01

On the basis of monthly runoff series obtained in 1950-2013 and annual sediment load measured in 1956--2013 at five key hydrological stations in the middle and lower reaches of the Yangtze River basin, this study used the Mann-Kendall methods to identify trend and abrupt changes of runoff and sediment load in relation to human activities. The results were as follows: (1) The annual and flood season runoffs showed significant decreasing trends at Yichang station, and showed slight downward trends at Hankou and Datong stations, while the abrupt changes of dry season runoff at Yichang, Hankou and Datong stations occurred in about 2007 and the change points were followed by significant increasing trends. The construction of the Three Gorges Dam, which began to operate in 2003, influenced the variations of runoff in the mainstream of Yangtze River, but the effect weakened with the distance along the downstream direction from TGD. (2) Since the 1990s, annual sediment loads at Yichang, Hankou, and Datong stations have been decreasing significantly, and after 2002, the annual sediment load at Yichang dropped below that of Hankou and Datong. The dams and deforestation/forestation contributed to the significant decreasing trend of the sediment load. In addition, the Three Gorges Dam aggravated the downward trend and caused the erosion of the riverbed and riverbanks in the middle and lower reaches. (3) The runoff and sediment load flowing from Dongting Lake into the mainstream of the Yangtze River showed significant decreasing trends at Chenglingji station after 1970s, and in contrast, slight increase in the sediment flow from Poyang Lake to the mainstream of the Yangtze River at Hukou station were detected over the post-TGD period (2003-2013). The result of the study will be an important foundation for watershed sustainable development of the Yangtze River under the human activities.

Variations of Runoff and Sediment Load in the Middle and Lower Reaches of the Yangtze River, China (1950-2013)

Science.gov (United States)

Li, Na; Wang, Lachun; Zeng, Chunfen; Wang, Dong; Liu, Dengfeng; Wu, Xutong

2016-01-01

On the basis of monthly runoff series obtained in 1950–2013 and annual sediment load measured in 1956–-2013 at five key hydrological stations in the middle and lower reaches of the Yangtze River basin, this study used the Mann-Kendall methods to identify trend and abrupt changes of runoff and sediment load in relation to human activities. The results were as follows: (1) The annual and flood season runoffs showed significant decreasing trends at Yichang station, and showed slight downward trends at Hankou and Datong stations, while the abrupt changes of dry season runoff at Yichang, Hankou and Datong stations occurred in about 2007 and the change points were followed by significant increasing trends. The construction of the Three Gorges Dam, which began to operate in 2003, influenced the variations of runoff in the mainstream of Yangtze River, but the effect weakened with the distance along the downstream direction from TGD. (2) Since the 1990s, annual sediment loads at Yichang, Hankou, and Datong stations have been decreasing significantly, and after 2002, the annual sediment load at Yichang dropped below that of Hankou and Datong. The dams and deforestation/forestation contributed to the significant decreasing trend of the sediment load. In addition, the Three Gorges Dam aggravated the downward trend and caused the erosion of the riverbed and riverbanks in the middle and lower reaches. (3) The runoff and sediment load flowing from Dongting Lake into the mainstream of the Yangtze River showed significant decreasing trends at Chenglingji station after 1970s, and in contrast, slight increase in the sediment flow from Poyang Lake to the mainstream of the Yangtze River at Hukou station were detected over the post-TGD period (2003–2013). The result of the study will be an important foundation for watershed sustainable development of the Yangtze River under the human activities. PMID:27479591

Variations of Runoff and Sediment Load in the Middle and Lower Reaches of the Yangtze River, China (1950-2013.

Directory of Open Access Journals (Sweden)

Na Li

Full Text Available On the basis of monthly runoff series obtained in 1950-2013 and annual sediment load measured in 1956--2013 at five key hydrological stations in the middle and lower reaches of the Yangtze River basin, this study used the Mann-Kendall methods to identify trend and abrupt changes of runoff and sediment load in relation to human activities. The results were as follows: (1 The annual and flood season runoffs showed significant decreasing trends at Yichang station, and showed slight downward trends at Hankou and Datong stations, while the abrupt changes of dry season runoff at Yichang, Hankou and Datong stations occurred in about 2007 and the change points were followed by significant increasing trends. The construction of the Three Gorges Dam, which began to operate in 2003, influenced the variations of runoff in the mainstream of Yangtze River, but the effect weakened with the distance along the downstream direction from TGD. (2 Since the 1990s, annual sediment loads at Yichang, Hankou, and Datong stations have been decreasing significantly, and after 2002, the annual sediment load at Yichang dropped below that of Hankou and Datong. The dams and deforestation/forestation contributed to the significant decreasing trend of the sediment load. In addition, the Three Gorges Dam aggravated the downward trend and caused the erosion of the riverbed and riverbanks in the middle and lower reaches. (3 The runoff and sediment load flowing from Dongting Lake into the mainstream of the Yangtze River showed significant decreasing trends at Chenglingji station after 1970s, and in contrast, slight increase in the sediment flow from Poyang Lake to the mainstream of the Yangtze River at Hukou station were detected over the post-TGD period (2003-2013. The result of the study will be an important foundation for watershed sustainable development of the Yangtze River under the human activities.

Analysis of Fluvial Sediment Discharges into Kubanni Reservoir ...

African Journals Online (AJOL)

User

The predominant sandy-clay sediment in the reservoir has an estimated total sediment load ... NIGERIAN JOURNAL OF TECHNOLOGY, VOL. 29 NO 2, JUNE ... the upper limit of application is 1-5gl !1 ... Laursen, Modified Einstein Procedure,.

Rainfall erosivity and sediment load over the Poyang Lake Basin under variable climate and human activities since the 1960s

Science.gov (United States)

Gu, Chaojun; Mu, Xingmin; Gao, Peng; Zhao, Guangju; Sun, Wenyi; Yu, Qiang

2018-03-01

Accelerated soil erosion exerts adverse effects on water and soil resources. Rainfall erosivity reflects soil erosion potential driven by rainfall, which is essential for soil erosive risk assessment. This study investigated the spatiotemporal variation of rainfall erosivity and its impacts on sediment load over the largest freshwater lake basin of China (the Poyang Lake Basin, abbreviate to PYLB). The spatiotemporal variations of rainfall erosivity from 1961 to 2014 based on 57 meteorological stations were detected using the Mann-Kendall test, linear regression, and kriging interpolation method. The sequential t test analysis of regime shift (STARS) was employed to identify the abrupt changes of sediment load, and the modified double mass curve was used to assess the impacts of rainfall erosivity variability on sediment load. It was found that there was significant increase (P change-points were identified in both 1985 and 2003. It was found that take annual rainfall erosivity as the explanatory variables of the double mass curves is more reasonable than annual rainfall and erosive rainfall. The estimation via the modified double mass curve demonstrated that compared with the period before change-point (1961-1984), the changes of rainfall erosivity increased 8.0 and 2.1% of sediment load during 1985-2002 and 2003-2014, respectively. Human activities decreased 50.2 and 69.7% of sediment load during the last two periods, which indicated effects of human activities on sediment load change was much larger than that of rainfall erosivity variability in the PYLB.

Analysis of Fluvial Sediment Discharges into Kubanni Reservoir ...

African Journals Online (AJOL)

The sediment discharges into the Kubanni Reservoir (KR) has been measured and analysed in this study. The predominant sandy-clay sediment in the reservoir has an estimated total sediment load of 20,387,000 kg/year. The depth and area coverage of the reservoir was surveyed using a defined distributed grid line ...

Effects of nutrient loading on the carbon balance of coastal wetland sediments

Science.gov (United States)

Morris, J.T.; Bradley, P.M.

1999-01-01

Results of a 12-yr study in an oligotrophic South Carolina salt marsh demonstrate that soil respiration increased by 795 g C m-2 yr-1 and that carbon inventories decreased in sediments fertilized with nitrogen and phosphorus. Fertilized plots became net sources of carbon to the atmosphere, and sediment respiration continues in these plots at an accelerated pace. After 12 yr of treatment, soil macroorganic matter in the top 5 cm of sediment was 475 g C m-2 lower in fertilized plots than in controls, which is equivalent to a constant loss rate of 40 g C m-2 yr-1. It is not known whether soil carbon in fertilized plots has reached a new equilibrium or continues to decline. The increase in soil respiration in the fertilized plots was far greater than the loss of sediment organic matter, which indicates that the increase in soil respiration was largely due to an increase in primary production. Sediment respiration in laboratory incubations also demonstrated positive effects of nutrients. Thus, the results indicate that increased nutrient loading of oligotrophic wetlands can lead to an increased rate of sediment carbon turnover and a net loss of carbon from sediments.

Geomorphic evolution of the Le Sueur River, Minnesota, USA, and implications for current sediment loading

Science.gov (United States)

Gran, K.B.; Belmont, P.; Day, S.S.; Jennings, C.; Johnson, Aaron H.; Perg, L.; Wilcock, P.R.

2009-01-01

There is clear evidence that the Minnesota River is the major sediment source for Lake Pepin and that the Le Sueur River is a major source to the Minnesota River. Turbidity levels are high enough to require management actions. We take advantage of the well-constrained Holocene history of the Le Sueur basin and use a combination of remote sensing, fi eld, and stream gauge observations to constrain the contributions of different sediment sources to the Le Sueur River. Understanding the type, location, and magnitude of sediment sources is essential for unraveling the Holocene development of the basin as well as for guiding management decisions about investments to reduce sediment loads. Rapid base-level fall at the outlet of the Le Sueur River 11,500 yr B.P. triggered up to 70 m of channel incision at the mouth. Slope-area analyses of river longitudinal profi les show that knickpoints have migrated 30-35 km upstream on all three major branches of the river, eroding 1.2-2.6 ?? 109 Mg of sediment from the lower valleys in the process. The knick zones separate the basin into an upper watershed, receiving sediment primarily from uplands and streambanks, and a lower, incised zone, which receives additional sediment from high bluffs and ravines. Stream gauges installed above and below knick zones show dramatic increases in sediment loading above that expected from increases in drainage area, indicating substantial inputs from bluffs and ravines.

Total Sediment Thickness of the World's Oceans & Marginal Seas

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A digital total-sediment-thickness database for the world's oceans and marginal seas has been compiled by the NOAA National Geophysical Data Center (NGDC). The data...

Determination of total arsenic in streams and sediments from Obuasi gold mines

International Nuclear Information System (INIS)

Serfor Armah, Yaw

1994-03-01

In this work streams and sediments of Obuasi, a major gold mining town in Ghana were analysed. In addition to the total arsenic the parameters determined included the levels of Pe, Al, Nn and Au and nutrients. Leaching of arsenic from the sediment was also carried out to ascertain the rate at which As will be removed from the sediment to acceptable levels. Results indicate that in spite of the newly installed Arsenic Recovery Plant (ARP) which is able to remove about 90% of the arsenic dusts, the streams in the area remain heavily polluted with arsenic. In the water Total Arsenic values range between 0.13 - 20.00ppm. The sediments are also polluted to a depth of at least 30cm with values ranging from 15.38 - 50.00ppm. Contrary to expectations, the gold concentration in both the water and sediment are too low and may not be suitable for exploration. The leaching results show that very little amount of arsenic was leached from the sediments. Even after 20 weeks of continuous leaching less than 1% of As had been leached. This was attributed to the ability of arsenic to form sparingly soluble compounds with Fe, Al, Mn etc in the sediment environment. (au)

Mud, models, and managers: Reaching consensus on a watershed strategy for sediment load reduction

Science.gov (United States)

Wilcock, P. R.; Cho, S. J.; Gran, K.; Belmont, P.; Hobbs, B. F.; Heitkamp, B.; Marr, J. D.

2017-12-01

Agricultural nonpoint source sediment pollution is a leading cause of impairment of U.S. waters. Sediment sources are often on private land, such that solutions require not only considerable investment, but broad acceptance among landowners. We present the story of a participatory modeling exercise whose goal was to develop a consensus strategy for reducing sediment loading from the Greater Blue Earth River Basin, a large (9,200 km2) watershed in southern Minnesota dominated by row crop agriculture. The Collaborative for Sediment Source Reduction was a stakeholder group of farmers, industry representatives, conservation groups, and regulatory agencies. We used a participatory modeling approach to promote understanding of the problem, to define the scope of solutions acceptable to farmers, to develop confidence in a watershed model, and to reach consensus on a watershed strategy. We found that no existing watershed model could provide a reliable estimate of sediment response to management actions and developed a purpose-built model that could provide reliable, transparent, and fast answers. Because increased stream flow was identified as an important driver of sediment loading, the model and solutions included both hydrologic and sediment transport components. The model was based on an annual sediment budget with management actions serving to proportionally reduce both sediment sources and sediment delivery. Importantly, the model was developed in collaboration with stakeholders, such that a shared understanding emerged regarding of the modeling challenges and the reliability of information used to strongly constrain model output. The simplicity of the modeling approach supported stakeholder engagement and understanding, thereby lowering the social barrier between expert modeler and concerned stakeholder. The consensus strategy focused on water storage higher in the watershed in order to reduce river discharge and the large supply of sediment from near

Trend of suspended sediment load in the Velika Morava River in the period 1967-2007

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Mustafić Sanja

2014-01-01

Full Text Available The paper is concerned with identifying changes in the time series of discharge (Q, suspended sediment concentration (SSC and sediment load (Qs of the Velika Morva River. The catchment area on farthest hydrological profile Ljubičevski most on Velika Morava River is approximately 35,496 km2. In this profile were carried out daily measurements of flow and concetration of silt in the period from 1967 to 2007. Average perennial transport of suspended sediment is 2.57ˣ106 t (72.4 t/km2/yr and ranged from 0.17ˣ106 t (4.8 t/km2/yr to 10.02ˣ106 t (282.2 t/km2/yr. Trends determined for Q, SSC and Qs are statistically obtained using the non-parametric Mann-Kendall test. Results of Mann-Kendall test show that Q has a slight declining trend of annual values which do not show statistical significance. Decline in trendline SSC and Qs is a significant at the level of 0.01. Calculating the standardized regression coefficients, it was found that the relative impact of SSC on sediment load is 3.1 time higher than the impact of discharge. From 1967 to 2007 the average decrease in sediment load at the mouth of the Velika Morava into the Danube was 3.1 t/km2/yr. [Projekat Ministarstva nauke Republike Srbije, br. 43007: The Research on Climate Change Influences on Environment: Influence Monitoring, Adaptation and Mitigation, subproject No. 9: Torrential Floods Frequency, Soil and Water Degradation as the Consequence of Global Changes

Early warning indicators for river nutrient and sediment loads in tropical seagrass beds: a benchmark from a near-pristine archipelago in Indonesia.

Science.gov (United States)

van Katwijk, M M; van der Welle, M E W; Lucassen, E C H E T; Vonk, J A; Christianen, M J A; Kiswara, W; al Hakim, I Inayat; Arifin, A; Bouma, T J; Roelofs, J G M; Lamers, L P M

2011-07-01

In remote, tropical areas human influences increase, potentially threatening pristine seagrass systems. We aim (i) to provide a bench-mark for a near-pristine seagrass system in an archipelago in East Kalimantan, by quantifying a large spectrum of abiotic and biotic properties in seagrass meadows and (ii) to identify early warning indicators for river sediment and nutrient loading, by comparing the seagrass meadow properties over a gradient with varying river influence. Abiotic properties of water column, pore water and sediment were less suitable indicators for increased sediment and nutrient loading than seagrass properties. Seagrass meadows strongly responded to higher sediment and nutrient loads and proximity to the coast by decreasing seagrass cover, standing stock, number of seagrass species, changing species composition and shifts in tissue contents. Our study confirms that nutrient loads are more important than water nutrient concentrations. We identify seagrass system variables that are suitable indicators for sediment and nutrient loading, also in rapid survey scenarios with once-only measurements. Copyright © 2011 Elsevier Ltd. All rights reserved.

Estimation of Streamflow and Fluvial Sediment Loads in the White Volta Basin under Future Climate Change

Science.gov (United States)

Lumor, M.; Amisigo, B. A.

2015-12-01

The White Volta Basin is one of the major sub-catchments of the Volta Basin of West Africa, covers an estimated 106,000 km2 and is shared between Burkina Faso and Ghana. The basin currently faces many challenges such as flooding, drought, high temporal and spatial variation of rainfall, deforestation, land degradation, climate change and high population growth rate. These challenges put pressure on the quantity and quality of the water resources in the basin. Current infrastructure developments in the basin have already impacted on the hydrological cycle, and future development plans potentially pose a threat to the sustainability of the resources if not appropriately managed. Information on runoff and sediment loads is a very important requirement for sustainable management of the water resources in the basin. This study therefore seeks to assess runoff and sediment loads in the White Volta Basin using the Soil Water Assessment Tool (SWAT) and provide understanding of how climate change impacts on future runoff and sediment loads in the basin.The model was calibrated for the period 1991 to 2003 and validated for the period 2004 to 2013.The model was also validated at one gauging station on the main river and another on a tributary. Analysis of the water balance of the basin shows that 4.90% of the simulated mean annual precipitation is converted to surface runoff while 84.37% evapotranspires. The results also show that the White Volta Basin contributes approximately 5.68x106tonnes/yr of sediment load into the Volta Lake. The calibrated model was used to simulate the water balance for the present time slice (1975-2005) as the basis for comparing with the future (2025-2055) water balance in the WhiteVolta Basin. The results show that annual surface runoff and sediment loads could increase by 56% and 70% respectively. A projected reduction by 0.54% in actual evapotranspiration is however estimated for the selected time period in the basin.

Chemical fractionation of lake sediments to determine the effects of land-use change on nutrient loading

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Heathwaite, A. L.

1994-07-01

Lake studies allow contemporary sediment and nutrient dynamics to be placed in a historical context in order that trends and rates of change in catchment inputs may be calculated. Here, a synthesis of the temporal information contained in catchment and lake sediment records is attempted. A chemical fractionation technique is used to isolate the different sediment sources contained in the lake core, and 210Pb dates provide an accurate record of changes in lake sediment sources over the past 100 years. The extent to which land-use records, collated from agricultural census returns, and process-based studies of sediment and nutrient export from different catchment land uses can be used to explain the trends observed in the lake sediments is examined. Sediment influx to the study lake has increased from less than 2 mm year -1 prior to the Second World War to over 10 mm year -1 at present. The source of the sediment is largely unaltered and unweathered allochthonous material eroded from the catchment. Land-use records suggest that the intensification of agriculture, characterized by a shift towards arable land immediately postwar, followed by an increase in the area of temporary grass in the 1960s, may be the cause of accelerated catchment erosion; both land-use changes would have increased the area of ploughed land in the catchment. An increase in the number of cattle and sheep in the catchment from around 2000 and 6000, respectively, in the 1940s, to a peak of nearly 7000 cattle and over 15 000 sheep in the 1980s, provides a further source of sediment and nutrients. Livestock are grazed on permanent grassland which is commonly located on steep hillslopes and in riparian zones where saturation-excess surface runoff may be an important hydrological pathway. Rainfall simulation experiments show that surface runoff from heavily grazed grassland has a high suspended sediment, ammonium-nitrogen and particulate phosphorus load. The combined effect of the long-term increase

A Satellite Imagery Approach to Monitor Turbidity and Total Suspended Sediments in Green Bay, WI

Science.gov (United States)

Khazaei, B.; Hamidi, S.; Hosseiny, S. M. H.; Ekhtari, N.

2017-12-01

Fox River is a major source of land-based pollutants, nutrients, and sediment that flows into the southern Green Bay (GB). GB supplies one-third of the total nutrient loading to Lake Michigan. This can play a significant role in the biological functioning of the Bay and development of managerial scenarios. To name a few, it can degrade the quality of the aquatic life, add to the costs for treatment processes, and reduce coastal quality. Water quality evaluation is a time consuming and costly process. Spaceborne imagery data provides a cheap and valuable source of information as an alternative for field monitoring of the water resources. Sediment is an optically active variable; hence; remote sensing techniques can be utilized to estimate Total Suspended Sediments (TSS) and Turbidity (TU) of water. In this study, we developed relationships between remote sensing imagery data with daily in situ measurements of TSS and TU in the summers of 2011 to 2014. Surface reflectance (SR) values obtained from Band 1 of MYD09GQ dataset-a level 2 product of MODerate Resolution Imaging Spectroradiometer (MODIS). This band covers SR between 620 and 670nm, in which, the wavelength is sensitive to mineral suspended matters most. After elimination of days with cloud contamination, 118 pairs of data remained for analysis. Several possible functions were tested and exponential function was the best estimator of the SR-TSS and SR-TU relationships with R2 values of 0.8269 and 0.8688, respectively. We then used 2014 data to validate the proposed functions. The model was able to estimate TSS and TU with NRMSE values of 0.36 and 0.30. It indicates that the model can be well-applied to predict TSS and TU within a reasonable margin of error. Then, equations were used to map the spatiotemporal dynamics of sediment in GB. Area of the plume ranges between 12 to 180 km2 while 50% of the time the area of the turbid plume is more than 106 km2. Expectedly, the concentration of sediment is much higher

Use of sediment rating curves and optical backscatter data to characterize sediment transport in the Upper Yuba River watershed, California, 2001-03

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Curtis, Jennifer A.; Flint, Lorraine E.; Alpers, Charles N.; Wright, Scott A.; Snyder, Noah P.

2006-01-01

Sediment transport in the upper Yuba River watershed, California, was evaluated from October 2001 through September 2003. This report presents results of a three-year study by the U.S. Geological Survey, in cooperation with the California Ecosystem Restoration Program of the California Bay-Delta Authority and the California Resources Agency. Streamflow and suspended-sediment concentration (SSC) samples were collected at four gaging stations; however, this report focuses on sediment transport at the Middle Yuba River (11410000) and the South Yuba River (11417500) gaging stations. Seasonal suspended-sediment rating curves were developed using a group-average method and non-linear least-squares regression. Bed-load transport relations were used to develop bed-load rating curves, and bed-load measurements were collected to assess the accuracy of these curves. Annual suspended-sediment loads estimated using seasonal SSC rating curves were compared with previously published annual loads estimated using the Graphical Constituent Loading Analysis System (GCLAS). The percent difference ranged from -85 percent to +54 percent and averaged -7.5 percent. During water year 2003 optical backscatter sensors (OBS) were installed to assess event-based suspended-sediment transport. Event-based suspended-sediment loads calculated using seasonal SSC rating curves were compared with loads calculated using calibrated OBS output. The percent difference ranged from +50 percent to -369 percent and averaged -79 percent. The estimated average annual sediment yield at the Middle Yuba River (11410000) gage (5 tons/mi2) was significantly lower than that estimated at the South Yuba River (11417500) gage (14 tons/mi2). In both rivers, bed load represented 1 percent or less of the total annual load throughout the project period. Suspended sediment at the Middle Yuba River (11410000) and South Yuba River (11417500) gages was typically greater than 85 percent silt and clay during water year 2003, and

Phosphorus and nitrogen loading depths in fluvial sediments following manure spill simulations

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Manure spills that enter streams can devastate the aquatic ecosystem. The depth of nitrogen (N) and phosphorus (P) loading in fluvial sediments following a manure spill have not been documented. Thus, the objectives of this study were (i) to determine the depth of N and P contamination as a result o...

Sediment transport and capacity change in three reservoirs, Lower Susquehanna River Basin, Pennsylvania and Maryland, 1900-2012

Science.gov (United States)

Langland, Michael J.

2015-01-01

The U.S. Geological Survey (USGS) has conducted numerous sediment transport studies in the Susquehanna River and in particular in three reservoirs in the Lower Susquehanna River Basin to determine sediment transport rates over the past century and to document changes in storage capacity. The Susquehanna River is the largest tributary to Chesapeake Bay and transports about one-half of the total freshwater input and substantial amounts of sediment and nutrients to the bay. The transported loads are affected by deposition in reservoirs (Lake Clarke, Lake Aldred, and Conowingo Reservoir) behind three hydropower dams. The geometry and texture of the deposited sediments in each reservoir upstream from the three dams has been a subject of research in recent decades. Particle size deposition and sediment scouring processes are part of the reservoir dynamics. A Total Maximum Daily Load (TMDL) for nitrogen, phosphorus, and sediment was established for Chesapeake Bay to attain water-quality standards. Six states and the District of Columbia agreed to reduce loads to the bay and to meet load allocation goals for the TMDL. The USGS has been estimating annual sediment loads at the Susquehanna River at Marietta, Pennsylvania (above Lake Clarke), and Susquehanna River at Conowingo, Maryland (below Conowingo Reservoir), since the mid-1980s to predict the mass balance of sediment transport through the reservoir system. Using streamflow and sediment data from the Susquehanna River at Harrisburg, Pennsylvania (upstream from the reservoirs), from 1900 to 1981, sediment loads were greatest in the early to mid-1900s when land disturbance activities from coal production and agriculture were at their peak. Sediment loads declined in the 1950s with the introduction of agricultural soil conservation practices. Loads were dominated by climatic factors in the 1960s (drought) and 1970s (very wet) and have been declining since the 1980s through 2012. The USGS developed a regression equation to

Sediment transport in two mediterranean regulated rivers.

Science.gov (United States)

Lobera, G; Batalla, R J; Vericat, D; López-Tarazón, J A; Tena, A

2016-01-01

Mediterranean climate is characterized by highly irregular rainfall patterns with marked differences between wet and dry seasons which lead to highly variable hydrological fluvial regimes. As a result, and in order to ensure water availability and reduce its temporal variability, a high number of large dams were built during the 20th century (more than 3500 located in Mediterranean rivers). Dams modify the flow regime but also interrupt the continuity of sediment transfer along the river network, thereby changing its functioning as an ecosystem. Within this context, the present paper aims to assess the suspended sediment loads and dynamics of two climatically contrasting Mediterranean regulated rivers (i.e. the Ésera and Siurana) during a 2-yr period. Key findings indicate that floods were responsible for 92% of the total suspended sediment load in the River Siurana, while this percentage falls to 70% for the Ésera, indicating the importance of baseflows on sediment transport in this river. This fact is related to the high sediment availability, with the Ésera acting as a non-supply-limited catchment due to the high productivity of the sources (i.e. badlands). In contrast, the Siurana can be considered a supply-limited system due to its low geomorphic activity and reduced sediment availability, with suspended sediment concentration remaining low even for high magnitude flood events. Reservoirs in both rivers reduce sediment load up to 90%, although total runoff is only reduced in the case of the River Ésera. A remarkable fact is the change of the hydrological character of the River Ésera downstream for the dam, shifting from a humid mountainous river regime to a quasi-invariable pattern, whereas the Siurana experiences the opposite effect, changing from a flashy Mediterranean river to a more constant flow regime below the dam. Copyright © 2015 Elsevier B.V. All rights reserved.

How have the river discharges and sediment loads changed in the Changjiang River basin downstream of the Three Gorges Dam?

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Guo, Leicheng; Su, Ni; Zhu, Chunyan; He, Qing

2018-05-01

Streamflow and sediment loads undergo remarkable changes in worldwide rivers in response to climatic changes and human interferences. Understanding their variability and the causes is of vital importance regarding river management. With respect to the Changjiang River (CJR), one of the largest river systems on earth, we provide a comprehensive overview of its hydrological regime changes by analyzing long time series of river discharges and sediment loads data at multiple gauge stations in the basin downstream of Three Gorges Dam (TGD). We find profound river discharge reduction during flood peaks and in the wet-to-dry transition period, and slightly increased discharges in the dry season. Sediment loads have reduced progressively since 1980s owing to sediment yield reduction and dams in the upper basin, with notably accelerated reduction since the start of TGD operation in 2003. Channel degradation occurs in downstream river, leading to considerable river stage drop. Lowered river stages have caused a 'draining effect' on lakes by fostering lake outflows following TGD impoundments. The altered river-lake interplay hastens low water occurrence inside the lakes which can worsen the drought given shrinking lake sizes in long-term. Moreover, lake sedimentation has decreased since 2002 with less sediment trapped in and more sediment flushed out of the lakes. These hydrological changes have broad impacts on river flood and drought occurrences, water security, fluvial ecosystem, and delta safety.

Reservoir Sedimentation and Upstream Sediment Sources: Perspectives and Future Research Needs on Streambank and Gully Erosion

Science.gov (United States)

Fox, G. A.; Sheshukov, A.; Cruse, R.; Kolar, R. L.; Guertault, L.; Gesch, K. R.; Dutnell, R. C.

2016-05-01

The future reliance on water supply and flood control reservoirs across the globe will continue to expand, especially under a variable climate. As the inventory of new potential dam sites is shrinking, construction of additional reservoirs is less likely compared to simultaneous flow and sediment management in existing reservoirs. One aspect of this sediment management is related to the control of upstream sediment sources. However, key research questions remain regarding upstream sediment loading rates. Highlighted in this article are research needs relative to measuring and predicting sediment transport rates and loading due to streambank and gully erosion within a watershed. For example, additional instream sediment transport and reservoir sedimentation rate measurements are needed across a range of watershed conditions, reservoir sizes, and geographical locations. More research is needed to understand the intricate linkage between upland practices and instream response. A need still exists to clarify the benefit of restoration or stabilization of a small reach within a channel system or maturing gully on total watershed sediment load. We need to better understand the intricate interactions between hydrological and erosion processes to improve prediction, location, and timing of streambank erosion and failure and gully formation. Also, improved process-based measurement and prediction techniques are needed that balance data requirements regarding cohesive soil erodibility and stability as compared to simpler topographic indices for gullies or stream classification systems. Such techniques will allow the research community to address the benefit of various conservation and/or stabilization practices at targeted locations within watersheds.

Quantifying the anthropogenic and climatic contributions to changes in water discharge and sediment load into the sea: A case study of the Yangtze River, China.

Science.gov (United States)

Zhao, Yifei; Zou, Xinqing; Gao, Jianhua; Xu, Xinwanghao; Wang, Chenglong; Tang, Dehao; Wang, Teng; Wu, Xiaowei

2015-12-01

Based on data from the Datong hydrological station and 147 meteorological stations, the influences of climate change and human activities on temporal changes in water discharge and sediment load were examined in the Yangtze River basin from 1953 to 2010. The Mann-Kendall test, abrupt change test (Mann-Kendall and cumulative anomaly test), and Morlet wavelet method were employed to analyze the water discharge and sediment load data measured at the Datong hydrological station. The results indicated that the annual mean precipitation and water discharge exhibited decreasing trends of -0.0064 mm/10 yr and -1.41×10(8) m3/yr, respectively, and that the water sediment load showed a significant decreasing trend of -46.5×10(6) t/yr. Meanwhile, an abrupt change in the water discharge occurred in 2003. The sediment load also exhibited an abrupt change in 1985. From 1970 to 2010, the climate change and human activities contributed 72% and 28%, respectively, to the water discharge reduction. The human-induced decrease in the sediment load was 914.03×10(6) t/yr during the 1970s and 3301.79×10(6) t/yr during the 2000s. The contribution from human activities also increased from 71% to 92%, especially in the 1990s, when the value increased to 92%. Climate change and human activities contributed 14% and 86%, respectively, to the sediment load reduction. Inter-annual variations in water discharge and sediment load were affected by climate oscillations and human activities. The effect of human activities on the sediment load was considerably greater than those on water discharge in the Yangtze River basin. Copyright © 2015 Elsevier B.V. All rights reserved.

Biochemical ripening of dredged sediments. Part 2. Degradation of polycyclic aromatic hydrocarbons and total petroleum hydorcarbons in slurried and consolidated sediments

NARCIS (Netherlands)

Vermeulen, J.; Gool, van M.P.M.; Mentink, G.H.; Joziasse, J.; Bruning, H.; Grotenhuis, J.T.C.

2007-01-01

Ripening of polycyclic aromatic hydrocarbons (PAH) and total petroleum hydrocarbons (TPH) polluted dredged sediment can be considered as a bioremediation technique. Aerobic biodegradation of PAH and TPH was studied in five previously anaerobic-slurried sediments during a 350-d laboratory incubation

Discharge and sediment loads at the Kings River Experimental Forest in the Southern Sierra Nevada of California

Science.gov (United States)

S.M. Eagan; C.T. Hunsaker; C.R. Dolanc; M.E. Lynch; C.R. Johnson

2007-01-01

The Kings River Experimental Watershed (KREW) is now in its third year of data collection on eight small perennial watersheds. We are collecting meteorology, stream discharge, sediment load, water chemistry, shallow soil water chemistry, vegetation, macro-invertebrate, stream microclimate, and air quality data. This paper primarily examines discharge and sediment data...

Comparison of depth-averaged concentration and bed load flux sediment transport models of dam-break flow

Directory of Open Access Journals (Sweden)

Jia-heng Zhao

2017-10-01

Full Text Available This paper presents numerical simulations of dam-break flow over a movable bed. Two different mathematical models were compared: a fully coupled formulation of shallow water equations with erosion and deposition terms (a depth-averaged concentration flux model, and shallow water equations with a fully coupled Exner equation (a bed load flux model. Both models were discretized using the cell-centered finite volume method, and a second-order Godunov-type scheme was used to solve the equations. The numerical flux was calculated using a Harten, Lax, and van Leer approximate Riemann solver with the contact wave restored (HLLC. A novel slope source term treatment that considers the density change was introduced to the depth-averaged concentration flux model to obtain higher-order accuracy. A source term that accounts for the sediment flux was added to the bed load flux model to reflect the influence of sediment movement on the momentum of the water. In a one-dimensional test case, a sensitivity study on different model parameters was carried out. For the depth-averaged concentration flux model, Manning's coefficient and sediment porosity values showed an almost linear relationship with the bottom change, and for the bed load flux model, the sediment porosity was identified as the most sensitive parameter. The capabilities and limitations of both model concepts are demonstrated in a benchmark experimental test case dealing with dam-break flow over variable bed topography.

Importance of measuring discharge and sediment transport in lesser tributaries when closing sediment budgets

Science.gov (United States)

Griffiths, Ronald E.; Topping, David J.

2017-11-01

Sediment budgets are an important tool for understanding how riverine ecosystems respond to perturbations. Changes in the quantity and grain size distribution of sediment within river systems affect the channel morphology and related habitat resources. It is therefore important for resource managers to know if a river reach is in a state of sediment accumulation, deficit or stasis. Many sediment-budget studies have estimated the sediment loads of ungaged tributaries using regional sediment-yield equations or other similar techniques. While these approaches may be valid in regions where rainfall and geology are uniform over large areas, use of sediment-yield equations may lead to poor estimations of loads in regions where rainfall events, contributing geology, and vegetation have large spatial and/or temporal variability. Previous estimates of the combined mean-annual sediment load of all ungaged tributaries to the Colorado River downstream from Glen Canyon Dam vary by over a factor of three; this range in estimated sediment loads has resulted in different researchers reaching opposite conclusions on the sign (accumulation or deficit) of the sediment budget for particular reaches of the Colorado River. To better evaluate the supply of fine sediment (sand, silt, and clay) from these tributaries to the Colorado River, eight gages were established on previously ungaged tributaries in Glen, Marble, and Grand canyons. Results from this sediment-monitoring network show that previous estimates of the annual sediment loads of these tributaries were too high and that the sediment budget for the Colorado River below Glen Canyon Dam is more negative than previously calculated by most researchers. As a result of locally intense rainfall events with footprints smaller than the receiving basin, floods from a single tributary in semi-arid regions can have large (≥ 10 ×) differences in sediment concentrations between equal magnitude flows. Because sediment loads do not

78 FR 13874 - Watershed Modeling To Assess the Sensitivity of Streamflow, Nutrient, and Sediment Loads to...

Science.gov (United States)

2013-03-01

... EPA's policy to include all comments it receives in the public docket without change and to make the... Modeling To Assess the Sensitivity of Streamflow, Nutrient, and Sediment Loads to Climate Change and Urban... Loads to Climate Change and Urban Development in 20 U.S. Watersheds (EPA/600/R-12/058). EPA also is...

Guidelines and Procedures for Computing Time-Series Suspended-Sediment Concentrations and Loads from In-Stream Turbidity-Sensor and Streamflow Data

Science.gov (United States)

Rasmussen, Patrick P.; Gray, John R.; Glysson, G. Douglas; Ziegler, Andrew C.

2009-01-01

In-stream continuous turbidity and streamflow data, calibrated with measured suspended-sediment concentration data, can be used to compute a time series of suspended-sediment concentration and load at a stream site. Development of a simple linear (ordinary least squares) regression model for computing suspended-sediment concentrations from instantaneous turbidity data is the first step in the computation process. If the model standard percentage error (MSPE) of the simple linear regression model meets a minimum criterion, this model should be used to compute a time series of suspended-sediment concentrations. Otherwise, a multiple linear regression model using paired instantaneous turbidity and streamflow data is developed and compared to the simple regression model. If the inclusion of the streamflow variable proves to be statistically significant and the uncertainty associated with the multiple regression model results in an improvement over that for the simple linear model, the turbidity-streamflow multiple linear regression model should be used to compute a suspended-sediment concentration time series. The computed concentration time series is subsequently used with its paired streamflow time series to compute suspended-sediment loads by standard U.S. Geological Survey techniques. Once an acceptable regression model is developed, it can be used to compute suspended-sediment concentration beyond the period of record used in model development with proper ongoing collection and analysis of calibration samples. Regression models to compute suspended-sediment concentrations are generally site specific and should never be considered static, but they represent a set period in a continually dynamic system in which additional data will help verify any change in sediment load, type, and source.

Total mercury concentrations in surface water and sediments from Danube Delta lakes

Directory of Open Access Journals (Sweden)

TEODOROF Liliana

2007-10-01

Full Text Available The samples were collected from surface water and sediments of Danube Delta lakes, during april and may 2006. The sediments were digested with nitric acid, and the surface water with real aqua, at Microwave Oven Anton Paar and analised at FIMS 400 Perkin Elmer. The results show that the total mercury is compared with the maximum allowed limits according with Normative 161/2006.

Internal loading of phosphorus in a sedimentation pond of a treatment wetland: effect of a phytoplankton crash.

Science.gov (United States)

Palmer-Felgate, Elizabeth J; Mortimer, Robert J G; Krom, Michael D; Jarvie, Helen P; Williams, Richard J; Spraggs, Rachael E; Stratford, Charlie J

2011-05-01

Sedimentation ponds are widely believed to act as a primary removal process for phosphorus (P) in nutrient treatment wetlands. High frequency in-situ P, ammonium (NH(4)(+)) and dissolved oxygen measurements, alongside occasional water quality measurements, assessed changes in nutrient concentrations and productivity in the sedimentation pond of a treatment wetland between March and June. Diffusive equilibrium in thin films (DET) probes were used to measure in-situ nutrient and chemistry pore-water profiles. Diffusive fluxes across the sediment-water interface were calculated from the pore-water profiles, and dissolved oxygen was used to calculate rates of primary productivity and respiration. The sedimentation pond was a net sink for total P (TP), soluble reactive P (SRP) and NH(4)(+) in March, but became subject to a net internal loading of TP, SRP and NH(4)(+) in May, with SRP concentrations increasing by up to 41μM (1300μl(-1)). Reductions in chlorophyll a and dissolved oxygen concentrations also occurred at this time. The sediment changed from a small net sink of SRP in March (average diffusive flux: -8.2μmolm(-2)day(-1)) to a net source of SRP in June (average diffusive flux: +1324μmolm(-2)day(-1)). A diurnal pattern in water column P concentrations, with maxima in the early hours of the morning, and minima in the afternoon, occurred during May. The diurnal pattern and release of SRP from the sediment were attributed to microbial degradation of diatom biomass, causing reduction of the dissolved oxygen concentration and leading to redox-dependent release of P from the sediment. In June, 2.7mol-Pday(-1) were removed by photosynthesis and 23mol-Pday(-1) were supplied by respiration in the lake volume. SRP was also released through microbial respiration within the water column, including the decomposition of algal matter. It is imperative that consideration to internal recycling is given when maintaining sedimentation ponds, and before the installation of new

Soft-sediment deformations (convolute lamination and load structures) in turbidites as indicators of flow reflections against bounding slopes

Science.gov (United States)

Tinterri, Roberto; Muzzi Magalhaes, Pierre; Tagliaferri, Alessio; Cunha, Rogerio S.; Laporta, Michele

2015-04-01

Soft-sediment deformations, such as convolute laminations, load structures and water escapes are very rapid deformations that occur in unconsolidated sediments near the depositional surface during or shortly after deposition and before significant diagenesis. These types of deformations develop when primary stratifications are deformed by a system of driving forces, while the sediment is temporarily in a weakened state due to the action of a deformation mechanism know as liquidization. This deformation occurs if the applied stress exceeds the sediment strength, either through an increase in the applied stress or through a temporary reduction in sediment strength. Liquidization mechanisms can be triggered by several agents, such as seismic shaking, rapid sedimentation with high-fallout rates or cyclic-pressure variations associated with storm waves or breaking waves. Consequently, soft-sediment deformations can be produced by different processes and form ubiquitous sedimentary structures characterizing many sedimentary environments. However, even though these types of structures are relatively well-known in terms of geometry and sedimentary characteristics, many doubts arise when the understanding of deformation and trigger mechanisms is attempted. As stressed also by the recent literature, the main problem lies in the fact that the existing approaches for the identification of triggering agents rely on criteria that are not diagnostic or not applicable to outcrop-based studies, because they are not always based on detailed facies analysis related to a paleoenvironmental-context approach. For this reason, this work discusses the significance of particular types of soft-sediment deformations that are very common in turbidite deposits, namely convolute laminations and load structures, especially on the basis of a deep knowledge of the stratigraphic framework and geological setting in which these structures are inserted. More precisely, detailed facies analyses of the

Fluvial sediment transport in a glacier-fed high-mountain river (Riffler Bach, Austrian Alps)

Science.gov (United States)

Morche, David; Weber, Martin; Faust, Matthias; Schuchardt, Anne; Baewert, Henning

2017-04-01

High-alpine environments are strongly affected by glacier retreat since the Little Ice Age (LIA). Due to ongoing climate change the hydrology of proglacial rivers is also influenced. It is expected that the growing proportions of snow melt and rainfall events will change runoff characteristics of proglacial rivers. Additionally, the importance of paraglacial sediment sources in recently deglaciating glacier forefields is increasing, while the role of glacial erosion is declining. Thus complex environmental conditions leading to a complex pattern of fluvial sediment transport in partly glaciated catchments of the European Alps. Under the umbrella of the joint PROSA-project the fluvial sediment transport of the river Riffler Bach (Kaunertal, Tyrol, Austria) was studied in 3 consecutive ablation seasons in order to quantify sediment yields. In June 2012 a probe for water level and an automatic water sampler (AWS) were installed at the outlet of the catchment (20km2). In order to calculate annual stage-discharge-relations by the rating-curve approach, discharge (Q) was repeatedly measured with current meters and by salt dilution. Concurrent to the discharge measurements bed load was collected using a portable Helley-Smith sampler. Bed load samples were weighted and sieved in the laboratory to gain annual bed load rating curves and grain size distributions. In total 564 (2012: 154, 2013: 209, 2014: 201) water samples were collected and subsequently filtered to quantify suspended sediment concentrations (SSC). Q-SSC-relations were calculated for single flood events due to the high variability of suspended sediment transport. The results show a high inter- and intra-annual variability of solid fluvial sediment transport, which can be explained by the characteristics of suspended sediment transport. Only 13 of 22 event-based Q-SSC-relations show causal dependency. In 2012, during a period with multiple pluvial-induced peak discharges most sediment was transported. On the

Selective leaching studies of deep-sea sediments loaded with americium, neptunium and plutonium

International Nuclear Information System (INIS)

Cole, T.G.; Higgo, J.J.W.; Cronan, D.S.; Rees, L.V.C.

1984-07-01

A series of selective leaching experiments were undertaken to investigate the solid phase speciation and distribution of americium, neptunium and plutonium which had been experimentally loaded onto different marine sediment types. The chemical leaches employed showed rather poor selectivity but certain trends were evident. Adsorption was not by ion exchange. Americium showed a preferential affinity for carbonate and plutonium for organic matter. Neptunium appeared to have no preferential affinities. Americium was sorbed by acetic acid residues (CaCO 3 removed) and by unleached carbonate-rich sediments with equal efficiency. This indicates that it is able to diversify its solid phase affinity/distribution depending upon which solid phases are available. (author)

Sediment and Nutrient Contributions from Subsurface Drains and Point Sources to an Agricultural Watershed

Directory of Open Access Journals (Sweden)

Bonnie Ball Coelho

2010-03-01

Full Text Available Excess sediment and nutrients in surface waters can threaten aquatic life. To determine the relative importance of subsurface drainage as a pathway for movement of sediment and nutrients to surface waters, loading from various tile systems was compared to that from sewage treatment plants (STP within the same watershed. Movement through tiles comprised 1 to 8% of estimated total (overland plus tile annual sediment loading from the respective areas drained by the tile. Load during the growing season from five closed drain- age systems without surface inlets averaged 5 kg sediment/ha, 0.005 kg dissolved reactive P (DRP/ha, 0.003 kg NH4-N/ha, and 3.8 kg NO3-N/ha; and from two open drainage systems with surface inlets averaged 14 kg sediment/ha, 0.03 kg DRP/ha, 0.04 kg NH4-N/ha, and 3.1 kg NO3-N/ha. The eight STP contributed about 44 530 kg suspended sediments, 3380 kg total P, 1340 kg NH4-N, and 116 900 kg NO3-N to the watershed annually. Drainage systems added less NH4-N and P, but more NO3-N and suspended solids to surface waters than STP. Tile drainage pathways for NO3-N, STP in the case of P, and overland pathways for sediment are indicated as targets to control loading in artificially drained agricultural watersheds.

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

Science.gov (United States)

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

Enhanced sediment loading facilitates point bar growth and accelerates bank erosion along a modelled meander bend on the Sacramento River, USA

Science.gov (United States)

Ahmed, J.; Constantine, J. A.; Hales, T. C.

2017-12-01

Meandering channels provide a conduit through which sediment and water is routed from the uplands to the sea. Alluvial material is periodically stored and transported through the channel network as permitted by the prevailing hydrologic conditions. The lowlands are typically characterised by accumulations of sediment attached to the inner banks of meander bends (point bars). These bedforms have been identified as important for facilitating a link between in-stream sediment supplies and channel dynamism. A 2D curvilinear hydrodynamic model (MIKE 21C) was used to perform a number of experiments in which the sediment load was adjusted to investigate how changes in alluvial material fluxes affect the development of point bars and the resultant patterns of bank erosion. A doubling of the sediment load caused a longitudinal increase in the bar in the upstream direction and caused a coeval doubling of the transverse channel slope at the meander apex. The upstream growth of the point bar was accompanied by an increase in length over which lateral migration took place at the outer bank. The magnitude of outer bank erosion was 9-times greater for the high-sediment simulation. These results suggest that enhanced sediment loads (potentially the result of changes in land use or climate) can trigger greater rates of bank erosion and channel change through the sequestration of alluvial material on point bars, which encourage high-velocity fluid deflection towards the outer bank of the meander. This controls riparian habitat development and exchanges of sediment and nutrients across the channel-floodplain interface.

Estimating sediment loads in an intra-Apennine catchments: balance between modeling and monitoring

Science.gov (United States)

Pelacani, Samanta; Cassi, Paola; Borselli, Lorenzo

2010-05-01

an 8 time increase in suspended sediment load. Furthermore, the fine-grained (Gis and field numerical assessment. Catena 75 (3): 268-277.

Observed runoff, jokulhlaups and suspended sediment load from the Greenland ice at Kangerlussuaq, West Greenland, 2007 and 2008

Energy Technology Data Exchange (ETDEWEB)

Mernild, Sebastian Haugard [Los Alamos National Laboratory; Hasholt, Bent [UNIV OF COPENHAGEN

2009-01-01

This study fills the gap in hydrologic measurements of runoff exiting a part of the Greenland Ice Sheet (GrIS), the Kangerlussuaq drainage area, West Greenland. The observations are of value for obtaining knowledge about the terrestrial freshwater and sediment output from part of the GrIS and the strip of land between the GrIS and the ocean, in the context of varying ice sheet surface melt and influx entering the ocean. High-resolution stage, discharge and suspended sediment load show a decrease in runoff of {approx} 25% and in sediment load of {approx} 40% from 2007 to 2008 in response to a decrease in the summer accumulated number of positive degree days. During the 2007 and 2008 runoff season, joekulhlaups are observed at Kangerlussuaq, drained from an ice-dammed lake at the margin of the GrIS.

Total and methyl mercury, moisture, and porosity in Lake Michigan surficial sediment

Data.gov (United States)

U.S. Environmental Protection Agency — Total and methyl mercury, moisture content (%), and porosity were measured in Lake Michigan sediment by the U.S. Environmental Protection Agency/Office of Research...

Total mercury in water, sediments, and animals along the Indian Coast

Digital Repository Service at National Institute of Oceanography (India)

Sanzgiri, S.; Mesquita, A.; Kureishy, T.W.

Total mercury (Hg) in water, sediments and animals along the coast of India is estimated. Water samples were collected on board of R.V. Gaveshani.The zooplankton samples were collected by Indian Ocean Standard Net and Heron Tranter nets of 500 mesh...

Modeling river total bed material load discharge using artificial intelligence approaches (based on conceptual inputs)

Science.gov (United States)

Roushangar, Kiyoumars; Mehrabani, Fatemeh Vojoudi; Shiri, Jalal

2014-06-01

This study presents Artificial Intelligence (AI)-based modeling of total bed material load through developing the accuracy level of the predictions of traditional models. Gene expression programming (GEP) and adaptive neuro-fuzzy inference system (ANFIS)-based models were developed and validated for estimations. Sediment data from Qotur River (Northwestern Iran) were used for developing and validation of the applied techniques. In order to assess the applied techniques in relation to traditional models, stream power-based and shear stress-based physical models were also applied in the studied case. The obtained results reveal that developed AI-based models using minimum number of dominant factors, give more accurate results than the other applied models. Nonetheless, it was revealed that k-fold test is a practical but high-cost technique for complete scanning of applied data and avoiding the over-fitting.

Vertical distribution of total carbon, nitrogen and phosphorus in sediments of Drug Spring Lake, Wudalianchi

Science.gov (United States)

Zeng, Ying; Yang, Chen

2018-02-01

The content of total organic carbon, total nitrogen and total phosphorus in sediments of Drug Spring Lake was detected and their vertical distribution characteristic was analysed. Results showed that there were significant changes to the content of total organic carbon, total nitrogen and total phosphorus in different depth of the columnar sediments. Their highest content both appeared in the interval of 10cm to 25cm corresponding to the period of 1980s to 1990s, when the tourism of Wudalianchi scenic area began to develop. It reflected the impact of human activities on the Drug Spring Lake. That means the regulation was still not enough, although a series of pollution control measures adopted by the government in recent years had initial success.

Sediment transport during the snow melt period in a Mediterranean high mountain catchment

Energy Technology Data Exchange (ETDEWEB)

Alvera, B.; Lana-Renault, N.; Garcia-Ruiz, J. M.

2009-07-01

Transport of suspended sediment and solutes during the snow melt period (May-June, 2004) in the Izas catchment (Central Pyrenees) was studied to obtain a sediment balance and to assess the annual importance of sediment transport. The results showed that most sediment was exported in the form of solutes (75,6% of the total); 24.4% was exported as suspended sediment and no bed load was recorded. Sediment transport during the snow melt period represented 42.7% of the annual sediment yield. (Author) 7 refs.

Sediment transport during the snow melt period in a Mediterranean high mountain catchment

International Nuclear Information System (INIS)

Alvera, B.; Lana-Renault, N.; Garcia-Ruiz, J. M.

2009-01-01

Transport of suspended sediment and solutes during the snow melt period (May-June, 2004) in the Izas catchment (Central Pyrenees) was studied to obtain a sediment balance and to assess the annual importance of sediment transport. The results showed that most sediment was exported in the form of solutes (75,6% of the total); 24.4% was exported as suspended sediment and no bed load was recorded. Sediment transport during the snow melt period represented 42.7% of the annual sediment yield. (Author) 7 refs.

Sedimentation, sediment quality, and upstream channel stability, John Redmond Reservoir, east-central Kansas, 1964-2009

Science.gov (United States)

Juracek, Kyle E.

2010-01-01

A combination of available bathymetric-survey information, bottom-sediment coring, and historical streamgage information was used to investigate sedimentation, sediment quality, and upstream channel stability for John Redmond Reservoir, east-central Kansas. Ongoing sedimentation is reducing the ability of the reservoir to serve several purposes including flood control, water supply, and recreation. The total estimated volume and mass of bottom sediment deposited between 1964 and 2009 in the conservation pool of the reservoir was 1.46 billion cubic feet and 55.8 billion pounds, respectively. The estimated sediment volume occupied about 41 percent of the conservation-pool, water-storage capacity of the reservoir. Water-storage capacity in the conservation pool has been lost to sedimentation at a rate of about 1 percent annually. Mean annual net sediment deposition since 1964 in the conservation pool of the reservoir was estimated to be 1.24 billion pounds per year. Mean annual net sediment yield from the reservoir basin was estimated to be 411,000 pounds per square mile per year Information from sediment cores shows that throughout the history of John Redmond Reservoir, total nitrogen concentrations in the deposited sediment generally were uniform indicating consistent nitrogen inputs to the reservoir. Total phosphorus concentrations in the deposited sediment were more variable than total nitrogen indicating the possibility of changing phosphorus inputs to the reservoir. As the principal limiting factor for primary production in most freshwater environments, phosphorus is of particular importance because increased inputs can contribute to accelerated reservoir eutrophication and the production of algal toxins and taste-and-odor compounds. The mean annual net loads of total nitrogen and total phosphorus deposited in the bottom sediment of the reservoir were estimated to be 2,350,000 pounds per year and 1,030,000 pounds per year, respectively. The estimated mean annual

RECENT DYNAMICS (1975 - 2012 OF COŞUŞTEA RIVER'S SUSPENDED SEDIMENT LOAD AT CORCOVA HYDROMETRIC STATION

Directory of Open Access Journals (Sweden)

Gabriela Adina MOROȘANU

2016-03-01

Full Text Available This paper aims to assess, from a statistical standpoint, the solid discharge at Corcova hydrometric station for the recent period between 1975 and 2012. The Corcova hydrometric station is located in the lowermost sector of the Coşuştea River Basin, at a distance of 2 km north-west from its confluence with Motru River. The usefulness of this study results from the endeavor to determine the years and months when the river presents an accumulation potential due to a higher transmission rate of the suspended sediment load. The statistical techniques applied in this study made use of the monthly, as well as the annual averages, minimum and maximum values of suspended sediment loads, in order to obtain the multiannual trends, seasonal and monthly differences. Thus, by using the Mann-Kendall test, the statistical distributions and frequency analysis, we could notice that the average solid discharge decreased in the last decades during the winter period, while between April and November, average solid discharge rose slightly, with a greater significance in May. Conversely, minimum solid discharge values were likely to indicate the years and months when the river’s solid intake was low, with the potential for bank erosion. The minimum values of suspended sediment loads showed little variation from year to year in all months, except for May and June, based on the influence of the peak liquid discharge on the potential erosion and sediment transport of Cosustea river. As a general conclusion, the most important aspects turned out to be the variations in April - June period, an interval well known for flash floods and high waters records, as well as for rapid changes in average, minimum and maximum solid flows.

Rainfall, runoff and sediment transport in a Mediterranean mountainous catchment.

Science.gov (United States)

Tuset, J; Vericat, D; Batalla, R J

2016-01-01

The relation between rainfall, runoff, erosion and sediment transport is highly variable in Mediterranean catchments. Their relation can be modified by land use changes and climate oscillations that, ultimately, will control water and sediment yields. This paper analyses rainfall, runoff and sediment transport relations in a meso-scale Mediterranean mountain catchment, the Ribera Salada (NE Iberian Peninsula). A total of 73 floods recorded between November 2005 and November 2008 at the Inglabaga Sediment Transport Station (114.5 km(2)) have been analysed. Suspended sediment transport and flow discharge were measured continuously. Rainfall data was obtained by means of direct rain gauges and daily rainfall reconstructions from radar information. Results indicate that the annual sediment yield (2.3 t km(-1) y(-1) on average) and the flood-based runoff coefficients (4.1% on average) are low. The Ribera Salada presents a low geomorphological and hydrological activity compared with other Mediterranean mountain catchments. Pearson correlations between rainfall, runoff and sediment transport variables were obtained. The hydrological response of the catchment is controlled by the base flows. The magnitude of suspended sediment concentrations is largely correlated with flood magnitude, while sediment load is correlated with the amount of direct runoff. Multivariate analysis shows that total suspended load can be predicted by integrating rainfall and runoff variables. The total direct runoff is the variable with more weight in the equation. Finally, three main hydro-sedimentary phases within the hydrological year are defined in this catchment: (a) Winter, where the catchment produces only water and very little sediment; (b) Spring, where the majority of water and sediment is produced; and (c) Summer-Autumn, when little runoff is produced but significant amount of sediments is exported out of the catchment. Results show as land use and climate change may have an important

Rainfall-induced runoff from exposed streambed sediments: an important source of water pollution.

Science.gov (United States)

Frey, S K; Gottschall, N; Wilkes, G; Grégoire, D S; Topp, E; Pintar, K D M; Sunohara, M; Marti, R; Lapen, D R

2015-01-01

When surface water levels decline, exposed streambed sediments can be mobilized and washed into the water course when subjected to erosive rainfall. In this study, rainfall simulations were conducted over exposed sediments along stream banks at four distinct locations in an agriculturally dominated river basin with the objective of quantifying the potential for contaminant loading from these often overlooked runoff source areas. At each location, simulations were performed at three different sites. Nitrogen, phosphorus, sediment, fecal indicator bacteria, pathogenic bacteria, and microbial source tracking (MST) markers were examined in both prerainfall sediments and rainfall-induced runoff water. Runoff generation and sediment mobilization occurred quickly (10-150 s) after rainfall initiation. Temporal trends in runoff concentrations were highly variable within and between locations. Total runoff event loads were considered large for many pollutants considered. For instance, the maximum observed total phosphorus runoff load was on the order of 1.5 kg ha. Results also demonstrate that runoff from exposed sediments can be a source of pathogenic bacteria. spp. and spp. were present in runoff from one and three locations, respectively. Ruminant MST markers were also present in runoff from two locations, one of which hosted pasturing cattle with stream access. Overall, this study demonstrated that rainfall-induced runoff from exposed streambed sediments can be an important source of surface water pollution. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Groundwater and Human Controls on the Suspended Sediment Load of Na Borges River, Mallorca (Spain)

Science.gov (United States)

Estrany, J.; Garcia, C.

2009-04-01

Groundwater dominance has important effects on the hydrological and geomorphological characteristics of river systems. Low suspended sediment concentrations and high water clarity are expected because significant inputs of sediment-free spring water dilute the suspended sediment generated by storms. However, in many Mediterranean temporary rivers, groundwater dominance is characterised by seasonal alternations of influent and effluent discharge involving significant variability on the sediment transport regimes. Such areas are often subject to soil and water conservation practices over the centuries that have reduced the sediment contribution from agricultural fields and favour subsurface flow to rivers. Moreover, urbanisation during the twentieth century has changed the catchment hydrology and altered basic river processes due to its ‘flashy' regime. In this context, we monitored suspended sediment fluxes by means of three nested sub-catchments during a two-year period in the Na Borges River, a lowland agricultural catchment (319 km2) on the island of Mallorca (Balearic Islands) managed and therefore modified since Roman Age by agricultural soil and water conservation practices and recently by urbanisation. The suspended sediment concentration (SSC) was lower when the base flow index (i.e., relative proportion of baseflow compared to stormflow, BFI) was higher. Considering the high variability of the Mediterranean climate, a significant scatter of daily average SSC between sites and seasonally was observed, ranging between 22 to 54 mg l-1 for the total study period. The maximum instantaneous peak surpassed 6,000 mg l-1, recorded at downstream site based on the sediment supplied when there was no baseflow and the rainfall intensity was remarkable. At the other sites, peak concentrations did not exceed 2,000 mg l-1 because groundwater plays a more significant role. Furthermore, strong seasonal contrasts explain the high SSC coefficient of variation, which is

Contributions of a Strengthened Early Holocene Monsoon and Sediment Loading to Present-Day Subsidence of the Ganges-Brahmaputra Delta

Science.gov (United States)

Karpytchev, M.; Ballu, V.; Krien, Y.; Becker, M.; Goodbred, S.; Spada, G.; Calmant, S.; Shum, C. K.; Khan, Z.

2018-02-01

The contribution of subsidence to relative sea level rise in the Ganges-Brahmaputra delta (GBD) is largely unknown and may considerably enhance exposure of the Bengal Basin populations to sea level rise and storm surges. This paper focuses on estimating the present-day subsidence induced by Holocene sediment in the Bengal Basin and by oceanic loading due to eustatic sea level rise over the past 18 kyr. Using a viscoelastic Earth model and sediment deposition history based on in situ measurements, results suggest that massive sediment influx initiated in the early Holocene under a strengthened South Asian monsoon may have contributed significantly to the present-day subsidence of the GBD. We estimate that the Holocene loading generates up to 1.6 mm/yr of the present-day subsidence along the GBD coast, depending on the rheological model of the Earth. This rate is close to the twentieth century global mean sea level rise (1.1-1.7 mm/yr). Thus, past climate change, by way of enhanced sedimentation, is impacting vulnerability of the GBD populations.

Runoff and Sediment load of the Yan River, China: changes over the last 60 yr

NARCIS (Netherlands)

Wang, F.; Mu, X.; Hessel, R.; Zhang, W.; Ritsema, C.J.; Li, R.

2013-01-01

Runoff and sediment load changes are affected by climate change and human activities in an integrated way. Historical insight into these effects can not only improve the knowledge of river processes, but also promote more effective land and water management. In this study, we looked at runoff and

Modeling the Response of Primary Production and Sedimentation to Variable Nitrate Loading in the Mississippi River Plume

National Research Council Canada - National Science Library

Green, Rebecca E; Breed, Greg A; Dagg, Michael J; Lohrenz, Steven E

2008-01-01

...% reduction in annual nitrogen discharge into the Gulf of Mexico. We developed an ecosystem model for the Mississippi River plume to investigate the response of organic matter production and sedimentation to variable nitrate loading...

Suspended sediment measurements and calculation of the particle load at HPP Fieschertal

Science.gov (United States)

Felix, D.; Albayrak, I.; Abgottspon, A.; Boes, R. M.

2016-11-01

In the scope of a research project on hydro-abrasive erosion of Pelton turbines, a field study was conducted at the high-head HPP Fieschertal in Valais, Switzerland. The suspended sediment mass concentration (SSC) and particle size distribution (PSD) in the penstock have been continuously measured since 2012 using a combination of six measuring techniques. The SSC was on average 0.52 g/l and rose to 50 g/l in a major flood event in July 2012. The median particle size d 50 was usually 15 pm, rising up to 100 μm when particles previously having settled in the headwater storage tunnel were re-suspended at low water levels. The annual suspended sediment loads (SSL) varied considerably depending on flood events. Moreover, so-called particle loads (PLs) according to the relevant guideline of the International Electrotechnical Commission (IEC 62364) were calculated using four relations between particle size and the relative abrasion potential. For the investigated HPP, the time series of the SSL and the PLs had generally similar shapes over the three years. The largest differences among the PLs were observed during re-suspension events when the particles were considerably coarser than usual. Further investigations on the effects of particle sizes on hydroabrasive erosion of splitters and cut-outs of coated Pelton turbines are recommended.

Modeling transport of nutrients & sediment loads into Lake Tahoe under climate change

Science.gov (United States)

Riverson, John; Coats, Robert; Costa-Cabral, Mariza; Dettinger, Mike; Reuter, John; Sahoo, Goloka; Schladow, Geoffrey

2013-01-01

The outputs from two General Circulation Models (GCMs) with two emissions scenarios were downscaled and bias-corrected to develop regional climate change projections for the Tahoe Basin. For one model—the Geophysical Fluid Dynamics Laboratory or GFDL model—the daily model results were used to drive a distributed hydrologic model. The watershed model used an energy balance approach for computing evapotranspiration and snowpack dynamics so that the processes remain a function of the climate change projections. For this study, all other aspects of the model (i.e. land use distribution, routing configuration, and parameterization) were held constant to isolate impacts of climate change projections. The results indicate that (1) precipitation falling as rain rather than snow will increase, starting at the current mean snowline, and moving towards higher elevations over time; (2) annual accumulated snowpack will be reduced; (3) snowpack accumulation will start later; and (4) snowmelt will start earlier in the year. Certain changes were masked (or counter-balanced) when summarized as basin-wide averages; however, spatial evaluation added notable resolution. While rainfall runoff increased at higher elevations, a drop in total precipitation volume decreased runoff and fine sediment load from the lower elevation meadow areas and also decreased baseflow and nitrogen loads basin-wide. This finding also highlights the important role that the meadow areas could play as high-flow buffers under climatic change. Because the watershed model accounts for elevation change and variable meteorological patterns, it provided a robust platform for evaluating the impacts of projected climate change on hydrology and water quality.

Environmental Monitoring, Water Quality - Total Maximum Daily Load (TMDL)

Data.gov (United States)

NSGIC Education | GIS Inventory — The Clean Water Act Section 303(d) establishes the Total Maximum Daily Load (TMDL) program. The purpose of the TMDL program is to identify sources of pollution and...

Effects of changes in nutrient loading and composition on hypoxia dynamics and internal nutrient cycling of a stratified coastal lagoon

Science.gov (United States)

Zhu, Yafei; McCowan, Andrew; Cook, Perran L. M.

2017-10-01

The effects of changes in catchment nutrient loading and composition on the phytoplankton dynamics, development of hypoxia and internal nutrient dynamics in a stratified coastal lagoon system (the Gippsland Lakes) were investigated using a 3-D coupled hydrodynamic biogeochemical water quality model. The study showed that primary production was equally sensitive to changed dissolved inorganic and particulate organic nitrogen loads, highlighting the need for a better understanding of particulate organic matter bioavailability. Stratification and sediment carbon enrichment were the main drivers for the hypoxia and subsequent sediment phosphorus release in Lake King. High primary production stimulated by large nitrogen loading brought on by a winter flood contributed almost all the sediment carbon deposition (as opposed to catchment loads), which was ultimately responsible for summer bottom-water hypoxia. Interestingly, internal recycling of phosphorus was more sensitive to changed nitrogen loads than total phosphorus loads, highlighting the potential importance of nitrogen loads exerting a control over systems that become phosphorus limited (such as during summer nitrogen-fixing blooms of cyanobacteria). Therefore, the current study highlighted the need to reduce both total nitrogen and total phosphorus for water quality improvement in estuarine systems.

Effects of changes in nutrient loading and composition on hypoxia dynamics and internal nutrient cycling of a stratified coastal lagoon

Directory of Open Access Journals (Sweden)

Y. Zhu

2017-10-01

Full Text Available The effects of changes in catchment nutrient loading and composition on the phytoplankton dynamics, development of hypoxia and internal nutrient dynamics in a stratified coastal lagoon system (the Gippsland Lakes were investigated using a 3-D coupled hydrodynamic biogeochemical water quality model. The study showed that primary production was equally sensitive to changed dissolved inorganic and particulate organic nitrogen loads, highlighting the need for a better understanding of particulate organic matter bioavailability. Stratification and sediment carbon enrichment were the main drivers for the hypoxia and subsequent sediment phosphorus release in Lake King. High primary production stimulated by large nitrogen loading brought on by a winter flood contributed almost all the sediment carbon deposition (as opposed to catchment loads, which was ultimately responsible for summer bottom-water hypoxia. Interestingly, internal recycling of phosphorus was more sensitive to changed nitrogen loads than total phosphorus loads, highlighting the potential importance of nitrogen loads exerting a control over systems that become phosphorus limited (such as during summer nitrogen-fixing blooms of cyanobacteria. Therefore, the current study highlighted the need to reduce both total nitrogen and total phosphorus for water quality improvement in estuarine systems.

A field studies and modeling approach to develop organochlorine pesticide and PCB total maximum daily load calculations: Case study for Echo Park Lake, Los Angeles, CA

Energy Technology Data Exchange (ETDEWEB)

Vasquez, V.R., E-mail: vrvasquez@ucla.edu [Environmental Science and Engineering Program, University of California, Los Angeles, Los Angeles, CA 90095-1496 (United States); Curren, J., E-mail: janecurren@yahoo.com [Environmental Science and Engineering Program, University of California, Los Angeles, Los Angeles, CA 90095-1496 (United States); Lau, S.-L., E-mail: simlin@ucla.edu [Department of Civil and Environmental Engineering, University of California, Los Angeles, Los Angeles, CA 90095-1496 (United States); Stenstrom, M.K., E-mail: stenstro@seas.ucla.edu [Department of Civil and Environmental Engineering, University of California, Los Angeles, Los Angeles, CA 90095-1496 (United States); Suffet, I.H., E-mail: msuffet@ucla.edu [Environmental Science and Engineering Program, University of California, Los Angeles, Los Angeles, CA 90095-1496 (United States)

2011-09-01

Echo Park Lake is a small lake in Los Angeles, CA listed on the USA Clean Water Act Section 303(d) list of impaired water bodies for elevated levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in fish tissue. A lake water and sediment sampling program was completed to support the development of total maximum daily loads (TMDL) to address the lake impairment. The field data indicated quantifiable levels of OCPs and PCBs in the sediments, but lake water data were all below detection levels. The field sediment data obtained may explain the contaminant levels in fish tissue using appropriate sediment-water partitioning coefficients and bioaccumulation factors. A partition-equilibrium fugacity model of the whole lake system was used to interpret the field data and indicated that half of the total mass of the pollutants in the system are in the sediments and the other half is in soil; therefore, soil erosion could be a significant pollutant transport mode into the lake. Modeling also indicated that developing and quantifying the TMDL depends significantly on the analytical detection level for the pollutants in field samples and on the choice of octanol-water partitioning coefficient and bioaccumulation factors for the model. - Research highlights: {yields} Fugacity model using new OCP and PCB field data supports lake TMDL calculations. {yields} OCP and PCB levels in lake sediment were found above levels for impairment. {yields} Relationship between sediment data and available fish tissue data evaluated. {yields} Model provides approximation of contaminant sources and sinks for a lake system. {yields} Model results were sensitive to analytical detection and quantification levels.

Assessing effects of changing land use practices on sediment loads in Panther Creek, north coastal California

Science.gov (United States)

Madej, Mary Ann; Bundros, Greg; Klein, Randy

2011-01-01

Revisions to the California Forest Practice Rules since 1974 were intended to increase protection of water quality in streams draining timber harvest areas. The effects of improved timber harvesting methods and road designs on sediment loading are assessed for the Panther Creek basin, a 15.4 km2 watershed in Humboldt County, north coastal California. We compute land use statistics, analyze suspended sediment discharge rating curves, and compare sediment yields in Panther Creek to a control (unlogged) stream, Little Lost Man Creek. From 1978 to 2008, 8.2 km2 (over half the watershed) was clearcut and other timber management activities (thinning, selection cuts, and so forth) affected an additional 5.9 km2. Since 1984, 40.7 km of streams in harvest units received riparian buffer strip protection. Between 2000 and 2009, 22 km of roads were upgraded and 9.7 km were decommissioned, reducing potential sediment production by an estimated 40,000 m3. Road density is currently 3.1 km/km2. Sediment rating curves from 2005 to 2010 indicate a decrease in suspended sediment concentrations when compared to the pre-1996 period, although Panther Creek still has a higher sediment yield on a per unit area basis than the control stream.

Initial Quantification of Suspended Sediment Loads for Three Alaska North Slope Rivers

Directory of Open Access Journals (Sweden)

Erica Lamb

2016-09-01

Full Text Available This study provides an initial assessment of suspended sediment transport in three rivers on the Alaska North Slope. From 2011 to 2013, the Anaktuvuk (69°27′51.00′′ N, 151°10′07.00′′ W, Chandler (69°17′0.30′′ N, 151°24′16.14′′ W, and Itkillik (68°51′59.46′′ N, 150°2′24.00′′ W Rivers were monitored for a variety of hydrologic, meteorologic, and sedimentologic characteristics. Watershed response to summer precipitation events was examined for each river. Bed sediment grain-size distribution was calculated using a photographic grid technique. Mean sediment diameters were 27.1 and 41.5 mm (Samples A and B for the Chandler, 35.8 mm for the Anaktuvuk, and 65.0 mm for the Itkillik. Suspended sediment rating curves were developed for each river. Suspended sediment discharge was analyzed. In 2011 and 2013, most of the total annual suspended sediment transport occurred during spring melt and widespread rainfall events, respectively. The results show that each river reacts differently to environmental inputs such as rain and basin characteristics.

Quantification of Suspended Sediment Load by Double Correlation in the Watershed of Chellif (Algeria

Directory of Open Access Journals (Sweden)

Bouchelkia Hamid

2014-07-01

Full Text Available The sediment transport in rivers in Algeria is very high. However, it is poorly quantified in some wadis because of the absence and the shortage of data especially the concentration of fine particles and also the unavailability of gauging stations. To fill this gap, a technique for estimating sediment yield, based on data recorded at the gauging station has been developed. The estimation of suspended sediment yield was conducted by a statistical analysis with double correlation on average daily flow and solid concentrations. The results obtained by applying this model to the watershed Chellif are very encouraging because the correlation coefficients of the found models are between 61% and 91% for the first correlation and between 86% and 97% for the second correlation. The estimated quantity of suspended sediment load is between 2.35 and 4.12 million tonnes per year, it appears important; This is due to the vulnerability of the Chellif basin facing erosion, the importance of its area and the importance of fluid flows in wadi Cheliff and its torrential regime. Mention here some of the results and their significance to the study.

Effect Of Environmental Load On The Toxicity Of Bottom Sediments

Directory of Open Access Journals (Sweden)

Šestinová Oľga

2015-06-01

Full Text Available This study is devoted to Ecotoxicity tests, Terrestrial Plant Test (modification of OECD 208, Phytotoxkit microbiotest on Sinapis alba and chronic tests of Earthworm (Eisenia veneta, modification of OECD Guidelines for the testing of chemicals 317, Bioaccumulation in Terrestrial Oligochaetes on polluted sediments. Earthworms can accelerate the removal of contaminants from soil. The study materials are river sediments, which were obtained from a monitoring station - the Water reservoir the Ružín No.1 particularly, the river Hornád, Hnilec and sample from sludge bed Rudňany. The samples of sediment were used to assess of the potential phytotoxic effect of heavy metals on higher plants. Total mortality was established in earthworms using chronic toxicity test after 7 and 28 exposure days. Based on the phytotoxicity testing, phytotoxic effects of the metals contaminated sediments from the sludge bed Rudňany on S. alba seeds was observed. The largest concentration differences were recorded in the sample R7 after 7 days earthworms exposure. The earthworms mortality was not influenced by sediment neither after 7 nor 28 exposure days The spectra of samples H, HO and R showed broad peak at 1 419 - 1 512 cm−1 characteristic for carbonate radical. In the spectra of the samples (R and R7 the vibration of C-H groups at 2 926 and 2 921 cm−1, respectively were also observed, demonstrating the presence of organic matter. Our research will continue with determination of metals concentration in earthworms.

Using AnnAGNPS to Predict the Effects of Tile Drainage Control on Nutrient and Sediment Loads for a River Basin.

Science.gov (United States)

Que, Z; Seidou, O; Droste, R L; Wilkes, G; Sunohara, M; Topp, E; Lapen, D R

2015-03-01

Controlled tile drainage (CTD) can reduce pollutant loading. The Annualized Agricultural Nonpoint Source model (AnnAGNPS version 5.2) was used to examine changes in growing season discharge, sediment, nitrogen, and phosphorus loads due to CTD for a ∼3900-km agriculturally dominated river basin in Ontario, Canada. Two tile drain depth scenarios were examined in detail to mimic tile drainage control for flat cropland: 600 mm depth (CTD) and 200 mm (CTD) depth below surface. Summed for five growing seasons (CTD), direct runoff, total N, and dissolved N were reduced by 6.6, 3.5, and 13.7%, respectively. However, five seasons of summed total P, dissolved P, and total suspended solid loads increased as a result of CTD by 0.96, 1.6, and 0.23%. The AnnAGNPS results were compared with mass fluxes observed from paired experimental watersheds (250, 470 ha) in the river basin. The "test" experimental watershed was dominated by CTD and the "reference" watershed by free drainage. Notwithstanding environmental/land use differences between the watersheds and basin, comparisons of seasonal observed and predicted discharge reductions were comparable in 100% of respective cases. Nutrient load comparisons were more consistent for dissolved, relative to particulate water quality endpoints. For one season under corn crop production, AnnAGNPS predicted a 55% decrease (CTD) in dissolved N from the basin. AnnAGNPS v. 5.2 treats P transport from a surface pool perspective, which is appropriate for many systems. However, for assessment of tile drainage management practices for relatively flat tile-dominated systems, AnnAGNPS may benefit from consideration of P and particulate transport in the subsurface. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Total and available metal contents in sediments by synchrotron radiation total reflection X-ray fluorescence

International Nuclear Information System (INIS)

Moreira, Silvana; Sobrinho, Gilmar A.; Jesus, Edgar F.O. de; Lopes, Ricardo T.

2002-01-01

In this work the total and available contents of Al, Si, Cl, K, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Ba, Ce and Pb in sediments from river Atibaia were determined by Synchrotron Radiation Total Reflection X-Ray Fluorescence technique. The detection limits for K series varies from 200 ng.mL -1 for Al to 2 ng.mL -1 for Zn while for L series the value varies from 20 ng.mL -1 for Ba to 10 ng.mL -1 for Pb. The samples were submitted to two different processes, in order to obtain the total and biological available metal contents. The information about metal content is a important parameter for a correct evaluation about the hydrologic cycle in Piracicaba basin. All the measure were carried out at the National Synchrotron Light Laboratory, Campinas, SP, Brazil, using a white beam for excitation. (author)

Multiple stressor effects on marine infauna: responses of estuarine taxa and functional traits to sedimentation, nutrient and metal loading

KAUST Repository

Ellis, Joanne; Clark, D.; Atalah, J.; Jiang, W.; Taiapa, C.; Patterson, M.; Sinner, J.; Hewitt, J.

2017-01-01

loading and the documented interaction effects between multiple stressors have important implications for understanding and managing the ecological consequences of eutrophication, sedimentation and contaminants on coastal ecosystems.

Estimating risks for water-quality exceedances of total-copper from highway and urban runoff under predevelopment and current conditions with the Stochastic Empirical Loading and Dilution Model (SELDM)

Science.gov (United States)

Granato, Gregory E.; Jones, Susan C.; Dunn, Christopher N.; Van Weele, Brian

2017-01-01

The stochastic empirical loading and dilution model (SELDM) was used to demonstrate methods for estimating risks for water-quality exceedances of event-mean concentrations (EMCs) of total-copper. Monte Carlo methods were used to simulate stormflow, total-hardness, suspended-sediment, and total-copper EMCs as stochastic variables. These simulations were done for the Charles River Basin upstream of Interstate 495 in Bellingham, Massachusetts. The hydrology and water quality of this site were simulated with SELDM by using data from nearby, hydrologically similar sites. Three simulations were done to assess the potential effects of the highway on receiving-water quality with and without highway-runoff treatment by a structural best-management practice (BMP). In the low-development scenario, total copper in the receiving stream was simulated by using a sediment transport curve, sediment chemistry, and sediment-water partition coefficients. In this scenario, neither the highway runoff nor the BMP effluent caused concentration exceedances in the receiving stream that exceed the once in three-year threshold (about 0.54 percent). In the second scenario, without the highway, runoff from the large urban areas in the basin caused exceedances in the receiving stream in 2.24 percent of runoff events. In the third scenario, which included the effects of the urban runoff, neither the highway runoff nor the BMP effluent increased the percentage of exceedances in the receiving stream. Comparison of the simulated geometric mean EMCs with data collected at a downstream monitoring site indicates that these simulated values are within the 95-percent confidence interval of the geometric mean of the measured EMCs.

A Hydrograph-Based Sediment Availability Assessment: Implications for Mississippi River Sediment Diversion

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Timothy Rosen

2014-03-01

Full Text Available The Mississippi River Delta Plain has undergone substantial land loss caused by subsidence, relative sea-level rise, and loss of connectivity to the Mississippi River. Many restoration projects rely on diversions from the Mississippi River, but uncertainty exists about the timing and the amount of actually available sediment. This study examined long-term (1980–2010 suspended sediment yield as affected by different hydrologic regimes to determine actual suspended sediment availability and how this may affect diversion management. A stage hydrograph-based approach was employed to quantify total suspended sediment load (SSL of the lower Mississippi River at Tarbert Landing during three river flow conditions: Peak Flow Stage (stage = 16.8 m, discharge >32,000 m3 s−1, High Flow Stage (stage = 14.6 m, discharge = 25,000–32,000 m3 s−1, and Intermediate Flow Stage (Stage = 12.1 m, discharge = 18,000–25,000 m3 s−1. Suspended sediment concentration (SSC and SSL were maximized during High Flow and Intermediate Flow Stages, accounting for approximately 50% of the total annual sediment yield, even though duration of the stages accounted for only one-third of a year. Peak Flow Stage had the highest discharge, but significantly lower SSC (p < 0.05, indicating that diversion of the river at this stage would be less effective for sediment capture. The lower Mississippi River showed significantly higher SSC (p < 0.0001 and SSL (p < 0.0001 during the rising than the receding limb. When the flood pulse was rising, Intermediate Flow and High Flow Stages showed greater SSC and SSL than Peak Flow Stage. Together, Intermediate Flow and High Flow Stages on the rising limb annually discharged 28 megatonnes over approximately 42 days, identifying this to be the best period for sediment capture and diversion.

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

Science.gov (United States)

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

2013-01-01

The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers, Fort Worth District; City of Corpus Christi; Guadalupe-Blanco River Authority; San Antonio River Authority; and San Antonio Water System, developed, calibrated, and tested a Hydrological Simulation Program-FORTRAN (HSPF) watershed model to simulate streamflow and suspended-sediment concentrations and loads during 1958-2010 in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary in south Texas. Data available to simulate suspended-sediment concentrations and loads consisted of historical sediment data collected during 1942-82 in the study area and suspended-sediment concentration data collected periodically by the USGS during 2006-7 and 2010 at three USGS streamflow-gaging stations (08211000 Nueces River near Mathis, Tex. [the Mathis gage], 08211200 Nueces River at Bluntzer, Tex. [the Bluntzer gage], and 08211500 Nueces River at Calallen, Tex. [the Calallen gage]), and at one ungaged location on a Nueces River tributary (USGS station 08211050 Bayou Creek at Farm Road 666 near Mathis, Tex.). The Mathis gage is downstream from Wesley E. Seale Dam, which was completed in 1958 to impound Lake Corpus Christi. Suspended-sediment data collected before and after completion of Wesley E. Seale Dam provide insights to the effects of the dam and reservoir on suspended-sediment loads transported by the lower Nueces River downstream from the dam to the Nueces Estuary. Annual suspended-sediment loads at the Nueces River near the Mathis, Tex., gage were considerably lower for a given annual mean discharge after the dam was completed than before the dam was completed.

Surface Sediment Analysis on Petroleum Hydrocarbon and Total Organic Carbon from Coastal Area of Papar to Tuaran, Sabah

International Nuclear Information System (INIS)

Siti Aishah Mohd Ali; Payus, C.; Masni Mohd Ali

2015-01-01

Total petroleum hydrocarbons (TPH) and total organic carbon (TOC) were investigated in surface sediments along coastal area of Papar to Tuaran, Sabah. Surface sediment samples were collected in 24 different stations in each area by using Ponar grab sampler. Samples were extracted for TPH using standard method sediment/ sludge APHA 5520E and analyzed using UV/VIS spectrophotometer while for TOC method analysis using United Nations Environment Programme (UNEP)/ MAP Athens (2006). The range of TPH concentrations in surface sediments were recorded at 0.24 - 20.65 mg/ kg dw Miri crude oil equivalents, meanwhile the TOC percentage ranged from 0.03 - 4.02 %. In the mean time, the statistical analysis by Pearson correlation showed a positive correlation with coefficient, r = 0.790 which showing the TPH concentrations significantly have influence on the TOC accumulations in the surface sediment. (author)

Water Quality Assessment and Total Maximum Daily Loads Information (ATTAINS)

Data.gov (United States)

U.S. Environmental Protection Agency — The Water Quality Assessment TMDL Tracking And Implementation System (ATTAINS) stores and tracks state water quality assessment decisions, Total Maximum Daily Loads...

Groundwater control on the suspended sediment load in the Na Borges River, Mallorca, Spain

Science.gov (United States)

Estrany, Joan; Garcia, Celso; Batalla, Ramon J.

2009-05-01

, creating a minimum of wet conditions in the catchment to activate hydrological pathways and deliver sediment to the drainage network. The BFI is also related to sediment delivery processes, as the loads are higher with lower BFI, corroborating the fact that most sediment movement is caused by stormflow and its related factors. Overall, suspended sediment yields were very low (i.e., < 1 t km - 2 yr - 1 ) at all measuring sites. Such values are the consequence of the limited sediment delivery attributable to soil conservation practices, low surface runoff coefficients and specific geomorphic features of groundwater-dominated rivers, such as low drainage density, low gradient, steep valley walls and flat valley floors.

Nutrient, suspended sediment, and trace element loads in the Blackstone River Basin in Massachusetts and Rhode Island, 2007 to 2009

Science.gov (United States)

Zimmerman, Marc J.; Waldron, Marcus C.; DeSimone, Leslie A.

2015-01-01

Nutrients, suspended sediment, and trace element loads in the Blackstone River and selected tributaries were estimated from composite water-quality samples in order to better understand the distribution and sources of these constituents in the river basin. The flow-proportional composite water-quality samples were collected during sequential 2-week periods at six stations along the river’s main stem, at three stations on tributaries, and at four wastewater treatment plants in the Massachusetts segment of the basin from June 2007 to September 2009. Samples were collected at an additional station on the Blackstone River near the mouth in Pawtucket, Rhode Island, from September 2008 to September 2009. The flow-proportional composite samples were used to estimate average daily loads during the sampling periods; annual loads for water years 2008 and 2009 also were estimated for the monitoring station on the Blackstone River near the Massachusetts-Rhode Island border. The effects of hydrologic conditions and net attenuation of nitrogen were investigated for loads in the Massachusetts segment of the basin. Sediment resuspension and contaminant loading dynamics were evaluated in two Blackstone River impoundments, the former Rockdale Pond (a breached impoundment) and Rice City Pond.

Estimating suspended sediment yield, sedimentation controls and impacts in the Mellah Catchment of Northern Algeria

International Nuclear Information System (INIS)

Khanchoul, Kamel; Assassi Fella; Altschul, Robert

2009-01-01

This paper is an assessment of the suspended sediment yield in the Mellah Catchment of northern Algeria. We use discharge-sediment load relationships to explore the variability of water discharge and sediment load, and to investigate the impact of geomorphic factors disturbance on erosion and sedimentation. Suspended sediment load was analyzed in the Mellah Catchment (550 squre kms ) which was controlled by a gauging station to measure discharge and sediment transport. The relations between daily mean sediment concentration and daily mean water discharge were analyzed to develop sediment rating curves. For storms with no water samples, a sediment rating curve was developed. The technique involves stratification of data into discharge-based classes, the mean of which are used to fit a rating curve according to single flow data and season to provide various rating relationships. The mean annual sediment yield during the 24 years of the study period was 562 T km -2 in the Mellah Catchment. This drainage basin had high rainfall and runoff, the erosion was high. The high sediment yield in the Mellah basin could be explained by a high percentage of sparse grassland and cultivation developed on shallow marly silty-clayey soils with steep slopes often exceeding 12%. Almost all suspended sediment loads are transported during storm events that mainly occur in the winter and spring heavy and medium downpours. The scarceness of these events leads to a very large interseasonal variability of the wadi sediment fluxes. The negative impacts of this enhanced sediment mobility are directly felt in the western part of the basin which shows many mass movements, bank and gully erosion because cultivated areas are often bared during autumnal brief flash floods and furrowed downslope during the winter season. (author)

Geochemical Model And Normalization For Heavy Metals In The Bottom Sediments, Dubai, UAE.

OpenAIRE

El Sammak, A.A. [عمرو عبدالعزيز السماك

1999-01-01

Dubai creek can be considered as the focal point of Dubai. It has great importance for trading and aesthetic values. Total and leachable heavy metals (Cd, Co, Ni, Pb and Zn), organic carbon and total carbonate were studied in the bottom sediments of the creek. Pollution Load Index, statistical analysis, were used in order to quantify the pollution load as well as to discriminate the data into significant groups. Normalization of the data using organic carbon and total carbonate was done in or...

Understanding Sediment Sources, Pathways, and Sinks in Regional Sediment Management: Application of Wash Load and Bed-Material Load Concept

National Research Council Canada - National Science Library

Biedenham, David S; Hubbard, Lisa C; Thome, Colin R; Watson, Chester C

2006-01-01

... through the fluvial system for sediments derived from various bed, bank, gully, and catchment sources thereby providing a reliable analytical foundation for effective regional sediment management...

Sediment supply versus local hydraulic controls on sediment transport and storage in a river with large sediment loads

Science.gov (United States)

Dean, David; Topping, David; Schmidt, John C.; Griffiths, Ronald; Sabol, Thomas

2016-01-01

The Rio Grande in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, undergoes rapid geomorphic changes as a result of its large sediment supply and variable hydrology; thus, it is a useful natural laboratory to investigate the relative importance of flow strength and sediment supply in controlling alluvial channel change. We analyzed a suite of sediment transport and geomorphic data to determine the cumulative influence of different flood types on changing channel form. In this study, physically based analyses suggest that channel change in the Rio Grande is controlled by both changes in flow strength and sediment supply over different spatial and temporal scales. Channel narrowing is primarily caused by substantial deposition of sediment supplied to the Rio Grande during tributary-sourced flash floods. Tributary floods have large suspended-sediment concentrations, occur for short durations, and attenuate rapidly downstream in the Rio Grande, depositing much of their sediment in downstream reaches. Long-duration floods on the mainstem have the capacity to enlarge the Rio Grande, and these floods, released from upstream dams, can either erode or deposit sediment in the Rio Grande depending upon the antecedent in-channel sediment supply and the magnitude and duration of the flood. Geomorphic and sediment transport analyses show that the locations and rates of sand erosion and deposition during long-duration floods are most strongly controlled by spatial changes in flow strength, largely through changes in channel slope. However, spatial differences in the in-channel sediment supply regulate sediment evacuation or accumulation over time in long reaches (greater than a kilometer).

The effect of sediment loading in Fennoscandia and the Barents Sea during the last glacial cycle on glacial isostatic adjustment observations

Directory of Open Access Journals (Sweden)

W. van der Wal

2017-09-01

Full Text Available Models for glacial isostatic adjustment (GIA routinely include the effects of meltwater redistribution and changes in topography and coastlines. Since the sediment transport related to the dynamics of ice sheets may be comparable to that of sea level rise in terms of surface pressure, the loading effect of sediment deposition could cause measurable ongoing viscous readjustment. Here, we study the loading effect of glacially induced sediment redistribution (GISR related to the Weichselian ice sheet in Fennoscandia and the Barents Sea. The surface loading effect and its effect on the gravitational potential is modeled by including changes in sediment thickness in the sea level equation following the method of Dalca et al. (2013. Sediment displacement estimates are estimated in two different ways: (i from a compilation of studies on local features (trough mouth fans, large-scale failures, and basin flux and (ii from output of a coupled ice–sediment model. To account for uncertainty in Earth's rheology, three viscosity profiles are used. It is found that sediment transport can lead to changes in relative sea level of up to 2 m in the last 6000 years and larger effects occurring earlier in the deglaciation. This magnitude is below the error level of most of the relative sea level data because those data are sparse and errors increase with length of time before present. The effect on present-day uplift rates reaches a few tenths of millimeters per year in large parts of Norway and Sweden, which is around the measurement error of long-term GNSS (global navigation satellite system monitoring networks. The maximum effect on present-day gravity rates as measured by the GRACE (Gravity Recovery and Climate Experiment satellite mission is up to tenths of microgal per year, which is larger than the measurement error but below other error sources. Since GISR causes systematic uplift in most of mainland Scandinavia, including GISR in GIA models

Loads of suspended sediment and nutrients from local nonpoint sources to the tidal Potomac River and Estuary, Maryland and Virginia, 1979-81 water years

Science.gov (United States)

Hickman, R. Edward

1987-01-01

Loads of suspended sediment, phosphorus, nitrogen, biochemical oxygen demand, and dissolved silica discharged to the tidal Potomac River and Estuary during the !979-81 water years from three local nonpoint sources have been calculated. The loads in rain falling directly upon the tidal water surface and from overflows of the combined sewer system of the District of Columbia were determined from available information. Loads of materials in the streamflow from local watersheds draining directly to the tidal Potomac River and Estuary downstream from Chain Bridge in Washington, D.C., were calculated from samples of streamflow leaving five monitored watersheds. Average annual yields of substances leaving three urban watersheds (Rock Creek and the Northwest and Northeast Branches of the Anacostia River) and the rural Saint Clements Creek watershed were calculated either by developing relationships between concentration and streamflow or by using the mean of measured concentrations. Yields calculated for the 1979-81 water years are up to 2.3 times period-of-record yields because of greater than average streamflow and stormflow during this 3-year period. Period-of-record yields of suspended sediment from the three urban watersheds and the Saint Clements Creek watershed do not agree with yields reported by other studies. The yields from the urban watersheds are 17 to 51 percent of yields calculated using sediment-concentration data collected during the 1960-62 water years. Previous studies suggest that this decrease is at least partly due to the imposition of effective sediment controls at construction sites and to the construction of two multipurpose reservoirs. The yield calculated for the rural Saint Clements Creek watershed is at least twice the yields calculated for other rural watersheds, a result that may be due to most of the samples of this stream being taken during the summer of the 1981 water year, a very dry period. Loads discharged from all local tributary

Hydraulic, water-quality, and temperature performance of three types of permeable pavement under high sediment loading conditions

Science.gov (United States)

Selbig, William R.; Buer, Nicolas

2018-05-11

Three permeable pavement surfaces - asphalt (PA), concrete (PC), and interlocking pavers (PIP) - were evaluated side-by-side to measure changes to the infiltrative capacity and water quality of stormwater runoff originating from a conventional asphalt parking lot in Madison, Wisconsin. During the 24-month monitoring period (2014-16), all three permeable pavements resulted in statistically significant reductions in the cumulative load of solids (total suspended solids and suspended sediment), total phosphorus, Escherichia coli (E. coli), and Enterococci. Most of the removal occurred through capture and retention in the void spaces of each permeable surface and aggregate base. The largest reduction in total suspended solids was for PC at 80 percent, followed by PIP and PA at 69 and 65 percent, respectively. Reductions (generally less than 50 percent) in total phosphorus also were observed, which might have been tempered by increases in the dissolved fraction observed in PIP and PA. Conversely, PC results indicated a slight reduction in dissolved phosphorus but failed to meet statistical significance. E. coli and Enterococci were reduced by about 80 percent for PC, almost twice the amount observed for PIP and PA.Results for the PIP and PC surfaces initially indicated higher pollutant load reduction than results for the PA surface. The efficiency of PIP and PC surfaces capturing sediment, however, led to a decline in infiltration rates that resulted in more runoff flowing over, not through, the permeable surface. This result led to a decline in treatment until the permeable surface was partially restored through maintenance practices, to which PIP responded more dramatically than PC or PA. Conversely, the PA surface was capable of infiltrating most of the influent runoff volume during the monitoring period and, thus, continued to provide some level of treatment. The combined effect of underdrain and overflow drainage resulted in similar pollutant treatment for all

Improvements in Quantifying Bank Erosion for Sediment Budgets within the Chesapeake Bay Watershed by Integrating Structure-From-Motion Photogrammetry

Science.gov (United States)

Bell, J. M.; Cashman, M. J.; Nibert, L.; Jackson, S.

2017-12-01

Fine sediment is a major source of pollution due to its ability to attenuate light, smother habitat, and sorb and transport nutrients, such as phosphorus and nitrogen. Piedmont streams in the Mid-Atlantic region of the United States are frequently characterized as incised with steep, highly erodible banks of legacy sediment that can contribute to high sediment loads. Multiple sediment fingerprinting studies in this region have demonstrated that stream banks can contribute a large proportion of the total sediment load, but stream banks are frequently overlooked in sediment delivery models and Total Maximum Daily Load allocations. The direct quantification of bank erosion is therefore essential to producing accurate sediment budgets, which are needed to inform the targeted mitigation and remediation of degraded fluvial systems. This study contrasts the use of traditional bank pin measurements, structure-from-motion photogrammetric techniques, and aerial LIDAR at sites within Maryland, USA. Bank pin measurements, representing only single points in space, were found to be highly variable with subjective initial placement often missing nearby, large-scale bank failures. In contrast, photogrammetric techniques, using structure-from-motion, were able to capture a more spatially-complete streambank profile. Using a Nikon D810 camera, bank scans were able to reconstruct banks with a RMSE as low as 0.1mm and repeat scan alignment resolution of bank-erosion over multi-year timescales. Future work will include difference mapping channel features at watershed scales. This photogrammetric approach of quantifying geomorphic change, when coupled with bank-sediment bulk density, has promise to accurately quantify volumetric change as well as sediment loads originating from bank erosion, and may provide valuable data of the quantification of bank erosion for incorporation into regional sediment models.

Assessing sedimentation rates at Usumacinta and Grijalva river basin (Southern Mexico) using OSL and suspended sediment load analysis: A study from the Maya Classic Period

Science.gov (United States)

Munoz-Salinas, E.; Castillo, M.; Sanderson, D.; Kinnaird, T.; Cruz-Zaragoza, E.

2013-12-01

Studying sedimentation rates on floodplains is key to understanding environmental changes occurred through time in river basins. The Usumacinta and Grijalva rivers flow most of their travel through the southern part of Mexico, forming a large river basin, crossing the states of Chiapas and Tabasco. The Usumacinta-Grijalva River Basin is within the 10 major rivers of North America, having a basin area of ~112 550 km2. We use the OSL technique for dating two sediment profiles and for obtaining luminescence signals in several sediment profiles located in the streambanks of the main trunk of the Usumacinta and Grijalva rivers. We also use mean annual values of suspended sediment load spanning ~50 years to calculate the sedimentation rates. Our OSL dating results start from the 4th Century, when the Maya Civilization was at its peak during the Classic Period. Sedimentation rates show a notable increase at the end of the 19th Century. The increase of the sedimentation rates seems to be related to changes in land uses in the Sierra Madre de Chiapas and Altos de Chiapas, based on deforestation and land clearing for developing new agrarian and pastoral activities. We conclude that the major environmental change in the basin of the Usumacinta and Grijalva Rivers since the Maya Classic Period was generated since the last Century as a result of an intense anthropogenic disturbance of mountain rain forest in Chiapas.

Impact of total organic carbon (in sediments) and dissolved organic carbon (in overlying water column) on Hg sequestration by coastal sediments from the central east coast of India

Digital Repository Service at National Institute of Oceanography (India)

Chakrabortya, P.; Sharma, B.M.; Babu, P.V.R.; Yao, K.M.; Jaychandran, S.

, 1991; Liu et al., 2006; Tack and Verloo, 1995). Mercury accumulates in sediment globally from many physical, chemical, biological, geological and anthropogenic environmental processes. Thus, sediment can be a good indicator of water quality of a...-Black method (Schumacher, 2002). This method has been widely used for the determination of total organic carbon in the soil and sediments. 3.0 Results and discussion The general description and texture analysis of the studied sediments are presented...

Assessing effects of changing land use practices on sediment loads in Panther Creek, north coastal California

Science.gov (United States)

Mary Ann Madej; Greg Bundros; Randy Klein

2012-01-01

Revisions to the California Forest Practice Rules since 1974 were intended to increase protection of water quality in streams draining timber harvest areas. The effects of improved timber harvesting methods and road designs on sediment loading are assessed for the Panther Creek basin, a 15.4 km2 watershed in Humboldt County, north coastal...

Summary of sediment data from the Yampa river and upper Green river basins, Colorado and Utah, 1993-2002

Science.gov (United States)

Elliott, John G.; Anders, Steven P.

2004-01-01

The water resources of the Upper Colorado River Basin have been extensively developed for water supply, irrigation, and power generation through water storage in upstream reservoirs during spring runoff and subsequent releases during the remainder of the year. The net effect of water-resource development has been to substantially modify the predevelopment annual hydrograph as well as the timing and amount of sediment delivery from the upper Green River and the Yampa River Basins tributaries to the main-stem reaches where endangered native fish populations have been observed. The U.S. Geological Survey, in cooperation with the Colorado Division of Wildlife and the U.S. Fish and Wildlife Service, began a study to identify sediment source reaches in the Green River main stem and the lower Yampa and Little Snake Rivers and to identify sediment-transport relations that would be useful in assessing the potential effects of hydrograph modification by reservoir operation on sedimentation at identified razorback spawning bars in the Green River. The need for additional data collection is evaluated at each sampling site. Sediment loads were calculated at five key areas within the watershed by using instantaneous measurements of streamflow, suspended-sediment concentration, and bedload. Sediment loads were computed at each site for two modes of transport (suspended load and bedload), as well as for the total-sediment load (suspended load plus bedload) where both modes were sampled. Sediment loads also were calculated for sediment particle-size range (silt-and-clay, and sand-and-gravel sizes) if laboratory size analysis had been performed on the sample, and by hydrograph season. Sediment-transport curves were developed for each type of sediment load by a least-squares regression of logarithmic-transformed data. Transport equations for suspended load and total load had coefficients of determination of at least 0.72 at all of the sampling sites except Little Snake River near

Sediment transport in the lower Snake and Clearwater River Basins, Idaho and Washington, 2008–11

Science.gov (United States)

Clark, Gregory M.; Fosness, Ryan L.; Wood, Molly S.

2013-01-01

/L), and the Middle Fork Clearwater River at Kooskia, Idaho (15 mg/L). The largest measured concentrations of suspended sediment (3,300 and 1,400 mg/L) during a rain-on-snow event in January 2011 were from samples collected at the Potlatch River near Spalding, Idaho, and the Palouse River at Hooper, Washington, respectively. Generally, samples collected from agricultural watersheds had a high percentage of silt and clay-sized suspended sediment, whereas samples collected from forested watersheds had a high percentage of sand. During water years 2009–11, Lower Granite Reservoir received about 10 million tons of suspended sediment from the combined loads of the Snake and Clearwater Rivers. The Snake River accounted for about 2.97 million tons per year (about 89 percent) of the total suspended sediment, 1.48 million tons per year (about 90 percent) of the suspended sand, and about 1.52 million tons per year (87 percent) of the suspended silt and clay. Of the suspended sediment transported to Lower Granite Reservoir, the Salmon River accounted for about 51 percent of the total suspended sediment, about 56 percent of the suspended sand, and about 44 percent of the suspended silt and clay. About 6.2 million tons (62 percent) of the sediment contributed to Lower Granite Reservoir during 2009–11 entered during water year 2011, which was characterized by an above average winter snowpack and sustained spring runoff. A comparison of historical data collected from the Snake River near Anatone with data collected during this study indicates that concentrations of total suspended sediment and suspended sand in the Snake River were significantly smaller during water years 1972–79 than during 2008–11. Most of the increased sediment content in the Snake River is attributable to an increase of sand-size material. During 1972–79, sand accounted for an average of 28 percent of the suspended-sediment load; during 2008–11, sand accounted for an average of 48 percent. Historical data

Importance of Dissolved Neutral Hg-Sulfides, Energy Rich Organic Matter and total Hg Concentrations for Methyl Mercury Production in Sediments

Science.gov (United States)

Drott, A.; Skyllberg, U.

2007-12-01

Methyl mercury (MeHg) is the mercury form that biomagnifies to the greatest extent in aquatic food webs. Therefore information about factors determining MeHg concentrations is critical for accurate risk assessment of contaminated environments. The concentration of MeHg in wetlands and sediments is the net result of: 1) methylation rates, 2) demethylation rates, and 3) input/output processes. In this study, the main controls on Hg methylation rates and total concentrations of MeHg, were investigated at eight sites in Sweden with sediments that had been subjected to local Hg contamination either as Hg(0), or as phenyl-Hg. Sediments were selected to represent a gradient in total Hg concentration, temperature climate, salinity, primary productivity, and organic C content and quality. Most sediments were high in organic matter content due to wood fibre efflux from pulp and paper industry. The pore water was analysed for total Hg, MeHg, DOC, H2S(aq), pH, DOC, Cl and Br. The chemical speciation of Hg(II) and MeHg in pore water was calculated using equilibrium models. Potential methylation and demethylation rates in sediments were determined in incubation experiments at 23° C under N2(g) for 48 h, after addition of isotopically enriched 201Hg(II) and Me204Hg. In all surface (0-20 cm) sediments there was a significant (pdetermined specific potential methylation rate constant (Km, day-1) and % MeHg (concentrations of MeHg normalized to total Hg) in the sediment. This indicates that MeHg production overruled degradation and input/output processes of MeHg in surface sediments, and that % MeHg in surface sediments may be used as a proxy for net production of MeHg. To our knowledge, these are the first data showing significant positive relationships between short term (48 h) MeHg production and longer term accumulation of MeHg, across a range of sites with different properties (1). If MeHg was not normalized to total Hg, the relationship was not significant. For sub-sets of

Contributions of human activities to suspended-sediment yield during storm events from a steep, small, tropical watershed, American Samoa

Science.gov (United States)

Messina, A. T.; Biggs, T. W.

2014-12-01

Anthropogenic watershed disturbance by agriculture, deforestation, roads, and urbanization can alter the timing, composition, and mass of sediment loads to adjacent coral reefs, causing enhanced sediment stress on corals near the outlets of impacted watersheds like Faga'alu, American Samoa. To quantify the increase in sediment loading to the adjacent priority coral reef experiencing sedimentation stress, suspended-sediment yield (SSY) from undisturbed and human-disturbed portions of a small, steep, tropical watershed was measured during baseflow and storm events of varying magnitude. Data on precipitation, discharge, turbidity, and suspended-sediment concentration (SSC) were collected over three field campaigns and continuous monitoring from January 2012 to March 2014, which included 88 storm events. A combination of paired- and nested-watershed study designs using sediment budget, disturbance ratio, and sediment rating curve methodologies was used to quantify the contribution of human-disturbed areas to total SSY. SSC during base- and stormflows was significantly higher downstream of an open-pit aggregate quarry, indicating the quarry is a key sediment source requiring sediment discharge mitigation. Comparison of event-wise SSY from the upper, undisturbed watershed, and the lower, human-disturbed watershed showed the Lower watershed accounted for more than 80% of total SSY on average, and human activities have increased total sediment loading to the coast by approximately 200%. Four storm characteristics were tested as predictors of event SSY using Pearson's and Spearman's correlation coefficients. Similar to mountainous watersheds in semi-arid and temperate watersheds, SSY from both the undisturbed and disturbed watersheds had the highest correlation with event maximum discharge, Qmax (Pearson's R=0.88 and 0.86 respectively), and were best fit by a power law relationship. The resulting model of event-SSY from Faga'alu is being incorporated as part of a larger

From agricultural intensification to conservation: sediment transport in the Raccoon River, Iowa, 1916-2009.

Science.gov (United States)

Jones, Christopher S; Schilling, Keith E

2011-01-01

Fluvial sediment is a ubiquitous pollutant that negatively affects surface water quality and municipal water supply treatment. As part of its routine water supply monitoring, the Des Moines Water Works (DMWW) has been measuring turbidity daily in the Raccoon River since 1916. For this study, we calibrated daily turbidity readings to modern total suspended solid (TSS) concentrations to develop an estimation of daily sediment concentrations in the river from 1916 to 2009. Our objectives were to evaluate long-term TSS patterns and trends, and relate these to changes in climate, land use, and agricultural practices that occurred during the 93-yr monitoring period. Results showed that while TSS concentrations and estimated sediment loads varied greatly from year to year, TSS concentrations were much greater in the early 20th century despite drier conditions and less discharge, and declined throughout the century. Against a backdrop of increasing discharge in the Raccoon River and widespread agricultural adaptations by farmers, sediment loads increased and peaked in the early 1970s, and then have slowly declined or remained steady throughout the 1980s to present. With annual sediment load concentrated during extreme events in the spring and early summer, continued sediment reductions in the Raccoon River watershed should be focused on conservation practices to reduce rainfall impacts and sediment mobilization. Overall, results from this study suggest that efforts to reduce sediment load from the watershed appear to be working. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Discharge, sediment, and water chemistry in Clear Creek, western Nevada, water years 2013–16

Science.gov (United States)

Huntington, Jena M.; Riddle, Daniel J.; Paul, Angela P.

2018-05-01

Clear Creek is a small stream that drains the eastern Carson Range near Lake Tahoe, flows roughly parallel to the Highway 50 corridor, and discharges to the Carson River near Carson City, Nevada. Historical and ongoing development in the drainage basin is thought to be affecting Clear Creek and its sediment-transport characteristics. Previous studies from water years (WYs) 2004 to 2007 and from 2010 to 2012 evaluated discharge, selected water-quality parameters, and suspended-sediment concentrations, loads, and yields at three Clear Creek sampling sites. This report serves as a continuation of the data collection and analyses of the Clear Creek discharge regime and associated water-chemistry and sediment concentrations and loads during WYs 2013–16.Total annual sediment loads ranged from 870 to 5,300 tons during WYs 2004–07, from 320 to 1,770 tons during WYs 2010–12, and from 50 to 200 tons during WYs 2013–16. Ranges in annual loads during the three study periods were not significantly different; however, total loads were greater during 2004–07 than they were during 2013–16. Annual suspended-sediment loads in WYs 2013–16 showed no significant change since WYs 2010–12 at sites 1 (U.S. Geological Survey reference site 10310485; Clear Creek above Highway 50, near Spooner Summit, Nevada) or 2 (U.S. Geological Survey streamgage 10310500; Clear Creek above Highway 50, near Spooner Summit, Nevada), but significantly lower loads at site 3 (U.S. Geological Survey site 10310518; Clear Creek at Fuji Park, at Carson City, Nevada), supporting the theory of sediment deposition between sites 2 and 3 where the stream gradient becomes more gradual. Currently, a threshold discharge of about 3.3 cubic feet per second is required to mobilize streambed sediment (bedload) from site 2 in Clear Creek. Mean daily discharge was significantly lower in 2010–12 than in 2004–07 and also significantly lower in 2013–16 than in 2010–12. During this study, lower bedload, and

A Synopsis of Technical Issues for Monitoring Sediment in Highway and Urban Runoff

Science.gov (United States)

Bent, Gardner C.; Gray, John R.; Smith, Kirk P.; Glysson, G. Douglas

2000-01-01

processing raw sediment samples (including homogenization and subsampling) for subsequent analysis for total suspended solids or suspended-sediment concentration often increase variance and may introduce bias. Processing artifacts can be substantial if the methods used are not appropriate for the concentrations and particle-size distributions present in the samples collected. Analytical methods for determining sediment concentrations include the suspended-sediment concentration and the total suspended solids methods. Although the terms suspended-sediment concentration and total suspended solids are often used interchangeably to describe the total concentration of suspended solid-phase material, the analytical methods differ and can produce substantially different results. The total suspended solids method, which commonly is used to produce highway- and urban-runoff sediment data, may not be valid for studies of runoff water quality. Studies of fluvial and highway-runoff sediment data indicate that analyses of samples by the total suspended solids method tends to under represent the true sediment concentration, and that relations between total suspended solids and suspended-sediment concentration are not transferable from site to site even when grain-size distribution information is available. Total suspended solids data used to calculate suspended-sediment loads in highways and urban runoff may be fundamentally unreliable. Consequently, use of total suspended solids data may have adverse consequences for the assessment, design, and maintenance of sediment-removal best management practices. Therefore, it may be necessary to analyze water samples using the suspended-sediment concentration method. Data quality, comparability, and utility are important considerations in collection, processing, and analysis of sediment samples and interpretation of sediment data for highway- and urban-runoff studies. Results from sediment studies must be comparable and readily transf

Total mercury in water and sediment from Honda Bay area in Palawan

International Nuclear Information System (INIS)

Kapauan, A.F.; Kapauan, P.A.; Tan, E.O.; Verceluz, F.P.

1980-01-01

This project is intended to pinpoint the sources of mercury contamination from the Honda Bay area in Palawan. Sampling sites were pinpointed which water and sediment samples were to be taken and kept in virgin polyethylene liter bottles. Analytical procedures were applied. The results of the analysis for total mercury content vary cosiderably from ml, less than 0.003 ng/9 to high of 0.419 ng/g with a considerable number of the sample going above the 0.100 ng/g level. Sediment samples also gave similar results, from a low of 0.004 ng/g to value higher than 2 ng/g round the jetty. It can be concluded, therefore, that the area surveyed is contaminated with mercury but not severely so. (author)

The economics of using prophylactic antibiotic-loaded bone cement in total knee replacement.

Science.gov (United States)

Gutowski, C J; Zmistowski, B M; Clyde, C T; Parvizi, J

2014-01-01

The rate of peri-prosthetic infection following total joint replacement continues to rise, and attempts to curb this trend have included the use of antibiotic-loaded bone cement at the time of primary surgery. We have investigated the clinical- and cost-effectiveness of the use of antibiotic-loaded cement for primary total knee replacement (TKR) by comparing the rate of infection in 3048 TKRs performed without loaded cement over a three-year period versus the incidence of infection after 4830 TKRs performed with tobramycin-loaded cement over a later period of time of a similar duration. In order to adjust for confounding factors, the rate of infection in 3347 and 4702 uncemented total hip replacements (THR) performed during the same time periods, respectively, was also examined. There were no significant differences in the characteristics of the patients in the different cohorts. The absolute rate of infection increased when antibiotic-loaded cement was used in TKR. However, this rate of increase was less than the rate of increase in infection following uncemented THR during the same period. If the rise in the rate of infection observed in THR were extrapolated to the TKR cohort, 18 additional cases of infection would have been expected to occur in the cohort receiving antibiotic-loaded cement, compared with the number observed. Depending on the type of antibiotic-loaded cement that is used, its cost in all primary TKRs ranges between USD $2112.72 and USD $112 606.67 per case of infection that is prevented.

Distribution of total phosphorus in the shelf sediments off the west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Murty, P.S.N.; Reddy, C.V.G.; Varadachari, V.V.R.

The total phosphorus content in the sediment samples collected from different stations on the continental shelf along five sections normal to the coast near Bombay, Karwar, Mangalore, Cochin and Alleppey has been determined and the distribution...

Quantifying modern erosion rates and river-sediment contamination in the Bolivian Andes

Science.gov (United States)

Vezzoli, Giovanni; Ghielmi, Giacomo; Mondaca, Gonzalo; Resentini, Alberto; Villarroel, Elena Katia; Padoan, Marta; Gentile, Paolo

2013-08-01

We use petrographic, mineralogical and geochemical data on modern river sediments of the Tupiza basin in the Bolivian Andes to investigate the relationships among human activity, heavy-metal contamination of sediments and modern erosion rates in mountain fluvial systems. Forward mixing model was used to quantify the relative contributions from each main tributary to total sediment load of the Tupiza River. The absolute sediment load was estimated by using the Pacific Southwest Inter Agency Committee model (PSIAC, 1968) after two years of geological field surveys (2009; 2010), together with data obtained from the Instituto Nacional del Agua public authority (INA, 2007), and suspended-load data from Aalto et al. (2006). Our results indicate that the sediment yield in the drainage basin is 910 ± 752 ton/km2year and the mean erosion rate is 0.40 ± 0.33 mm/year. These values compare well with erosion rates measured by Insel et al. (2010) using 10Be cosmogenic radionuclide concentrations in Bolivian river sediments. More than 40% of the Tupiza river load is produced in the upper part of the catchment, where highly tectonized and weathered rocks are exposed and coupled with sporadic land cover and intense human activity (mines). In the Rio Chilco basin strong erosion of upland valleys produce an increase of erosion (˜10 mm/year) and the influx of large amounts of sediment by mass wasting processes. The main floodplain of the Tupiza catchment represents a significant storage site for the heavy metals (˜657 ton/year). Fluvial sediments contain zinc, lead, vanadium, chromium, arsenic and nickel. Since the residence time of these contaminants in the alluvial plain may be more than 100 years, they may represent a potential source of pollution for human health.

Impacts of reforestation upon sediment load and water outflow in the Lower Yazoo River Watershed, Mississippi

Science.gov (United States)

Ying Ouyang; Theodor D. Leininger; Matt Moran

2013-01-01

Among the world’s largest coastal and river basins, the Lower Mississippi River Alluvial Valley (LMRAV)is one of the most disturbed by human activities. This study ascertained the impacts of reforestation on water outflow attenuation (i.e., water flow out of the watershed outlet) and sediment load reduction in the Lower Yazoo River Watershed (LYRW) within the LMRAV...

Continuous monitoring of sediment and nutrients in the Illinois River at Florence, Illinois, 2012-13

Science.gov (United States)

Terrio, Paul J.; Straub, Timothy D.; Domanski, Marian M.; Siudyla, Nicholas A.

2015-01-01

The Illinois River is the largest river in Illinois and is the primary contributing watershed for nitrogen, phosphorus, and suspended-sediment loading to the upper Mississippi River from Illinois. In addition to streamflow, the following water-quality constituents were monitored at the Illinois River at Florence, Illinois (U.S. Geological Survey station number 05586300), during May 2012–October 2013: phosphate, nitrate, turbidity, temperature, specific conductance, pH, and dissolved oxygen. The objectives of this monitoring were to (1) determine performance capabilities of the in-situ instruments; (2) collect continuous data that would provide an improved understanding of constituent characteristics during normal, low-, and high-flow periods and during different climatic and land-use seasons; (3) evaluate the ability to use continuous turbidity as a surrogate constituent to determine suspended-sediment concentrations; and (4) evaluate the ability to develop a regression model for total phosphorus using phosphate, turbidity, and other measured parameters. Reliable data collection was achieved, following some initial periods of instrument and data-communication difficulties. The resulting regression models for suspended sediment had coefficient of determination (R2) values of about 0.9. Nitrate plus nitrite loads computed using continuous data were found to be approximately 8 percent larger than loads computed using traditional discrete-sampling based models. A regression model for total phosphorus was developed by using historic orthophosphate data (important during periods of low flow and low concentrations) and historic suspended-sediment data (important during periods of high flow and higher concentrations). The R2of the total phosphorus regression model using orthophosphorus and suspended sediment was 0.8. Data collection and refinement of the regression models is ongoing.

Partitioning sediment flux by provenance and tracing erosion patterns in Taiwan

Science.gov (United States)

Resentini, Alberto; Goren, Liran; Castelltort, Sébastien; Garzanti, Eduardo

2017-07-01

We critically evaluate the potential and limitations of an alternative way to calculate erosion rates based on petrographic and mineralogical fingerprints of fluvial sediments coupled with gauged sediment fluxes. Our approach allows us to apportion sediment loads to different lithological units, and consequently to discriminate erosion rates in different tectonic domains within each catchment. Our provenance data on modern Taiwanese sands indicate focused erosion in the Backbone Range and Tananao Complex of the retrowedge. Lower rates are inferred for the northern part of the island characterized by tectonic extension and for the western foothills in the prowedge. The principal factor of uncertainty affecting our estimates is the inevitably inaccurate evaluation of total sediment load, because only the suspended flux was measured. Another is the assumption that suspended load and bed load are derived from the same sources in fixed proportions. Additional errors are caused by the insufficiently precise definition of lithologically similar compositional end-members and by the temporal variability of sediment composition at the outlet of each catchment related to the spatial variability of erosional processes and triggering agents such as earthquakes, typhoons, and landslides. To evaluate the robustness of our findings, we applied a morphometric technique based on the stream-power model. The results obtained are broadly consistent, with local discrepancies ascribed to poorly constrained assumptions and choices of scaling parameters. Our local erosion estimates are consistent with GPS uplift rates measured on a decadal timescale and generally higher than basin-wide results inferred from cosmogenic-nuclide and thermochronology data.

Increasing runoff and sediment load from the Greenland ice sheet at kangerlussuaq (Sonder Stromfjord) in a 30-year perspective, 1979-2008

Energy Technology Data Exchange (ETDEWEB)

Mernild, Sebastian Haugard [Los Alamos National Laboratory; Liston, Glen [COLORADO STATE UNIV.; Hasholt, Bent [UNIV OF COPENGAGEN; Steffen, Konrad [UNIV OF COLORADO; Van Den Broeke, Michiel [UTRECHT UNIV; Mcgrath, Daniel [UNIV OF COLORADO; Yde, Jacob [UNIV OF AARHUS

2009-01-01

This observation and modeling study provides insights into runoff and sediment load exiting the Watson River drainage basin, Kangerlussuaq, West Greenland during a 30 year period (1978/79-2007/08) when the climate experienced increasing temperatures and precipitation. The 30-year simulations quantify the terrestrial freshwater and sediment output from part of the Greenland Ice Sheet (GrIS) and the land between the GrIS and the ocean, in the context of global warming and increasing GrIS surface melt. We used a snow-evolution modeling system (SnowModel) to simulate the winter accumulation and summer ablation processes, including runoff and surface mass balance (SMB), of the Greenland ice sheet. Observed sediment concentrations were related to observed runoff, producing a sediment-load time series. To a large extent, the SMB fluctuations could be explained by changes in net precipitation (precipitation minus evaporation and sublimation), with 8 out of 30 years having negative SMB, mainly because of relatively low annual net precipitation. The overall trend in net precipitation and runoff increased significantly, while 5MB increased insignificantly throughout the simulation period, leading to enhanced precipitation of 0.59 km{sup 3} w.eq. (or 60%), runoff of 0.43 km{sup 3} w.eq (or 54%), and SMB of 0.16 km3 w.eq. (or 86%). Runoff rose on average from 0.80 km{sup 3} w.eq. in 1978/79 to 1.23 km{sup 3} w.eq. in 2007/08. The percentage of catchment oudet runoff explained by runoff from the GrIS decreased on average {approx} 10%, indicating that catchment runoff throughout the simulation period was influenced more by precipitation and snowmelt events, and less by runoff from the GrIS. Average variations in the increasing Kangerlussuaq runoff from 1978/79 through 2007/08 seem to follow the overall variations in satellite-derived GrIS surface melt, where 64% of the variations in simulated runoff were explained by regional melt conditions on the GrIS. Throughout the simulation

Chemical and physical characteristics of water and sediment in Scofield Reservoir, Carbon County, Utah

Science.gov (United States)

Waddell, Kidd M.; Darby, D.W.; Theobald, S.M.

1985-01-01

.1 milligrams per liter as nitrogen. The load of total nitrogen contributed by each stream was about proportional to the quantity of water contributed by the respective stream.For the combined inflow of Fish, Pondtown, and Mud Creeks, the discharge-weighted average concentration of total phosphorus was 0.06 milligram per liter as phosphorus. Percentages of the total phosphorus load contributed by Mud and Pondtown Creeks were significantly larger than their percentages of the total inflow. During October 1, 1979-August 31, 1980, Fish Creek contributed 72 percent of the inflowing water but only 60 percent of the total phosphorus load, Mud Creek contributed 16 percent of the total inflow but 24 percent of the total phosphorus load, and Pondtown Creek contributed 6 percent of the total inflow and 16 percent of the load of total phosphorus.Eccles Canyon is a major contributor of nutrients to Mud Creek, and most of the nutrient load occurs in the form of suspended organic material. During the snowmelt period, concentrations of total nitrogen and phosphorus were as much as 21 and 4.3 milligrams per liter at the gaging station in Eccles Canyon. The unusually large concentrations of nitrogen and phosphorus probably have resulted from flushing of residual debris from the canyon about 27.3 acres of forested land were cleared during 1979 for fire protection around new mine portals and for road rights-of-way.The concentrations of trace metals in the sediments near the inflow of Mud Creek are not greatly different from those in the middle of the reservoir, which suggests that sediments related to coal mining either have not affected the trace-metal concentrations in the sediments or, particularly for the fine-grained sediments, have been uniformly distributed over the reservoir bottom. The concentration of total extractable mercury in the sediments ranged from 0.08 to 0.20 part per million near the inflow of Mud Creek and from 0.08 to 0.46 part per million at a site near the middle of the

Landscape planning for agricultural nonpoint source pollution reduction III: Assessing phosphorus and sediment reduction potential

Science.gov (United States)

Diebel, M.W.; Maxted, J.T.; Robertson, Dale M.; Han, S.; Vander Zanden, M. J.

2009-01-01

Riparian buffers have the potential to improve stream water quality in agricultural landscapes. This potential may vary in response to landscape characteristics such as soils, topography, land use, and human activities, including legacies of historical land management. We built a predictive model to estimate the sediment and phosphorus load reduction that should be achievable following the implementation of riparian buffers; then we estimated load reduction potential for a set of 1598 watersheds (average 54 km2) in Wisconsin. Our results indicate that land cover is generally the most important driver of constituent loads in Wisconsin streams, but its influence varies among pollutants and according to the scale at which it is measured. Physiographic (drainage density) variation also influenced sediment and phosphorus loads. The effect of historical land use on present-day channel erosion and variation in soil texture are the most important sources of phosphorus and sediment that riparian buffers cannot attenuate. However, in most watersheds, a large proportion (approximately 70%) of these pollutants can be eliminated from streams with buffers. Cumulative frequency distributions of load reduction potential indicate that targeting pollution reduction in the highest 10% of Wisconsin watersheds would reduce total phosphorus and sediment loads in the entire state by approximately 20%. These results support our approach of geographically targeting nonpoint source pollution reduction at multiple scales, including the watershed scale. ?? 2008 Springer Science+Business Media, LLC.

Comparison of total and cold-extractable uranium in stream sediments of the southwestern Karoo supergroup, South Africa

International Nuclear Information System (INIS)

Jakob, W.R.O.; Smit, M.C.B.; Murphy, G.C.

1979-01-01

In order to evaluate the usefullness of cold-extractable uranium as a tool of uranium prospecting in stream sediments of the southwestern Karoo, South Africa, ten orientation studies were conducted near known mineralisation jointly by the Atomic Energy Board and the Geological Survey of South Africa. These indicate that the topography determines the nature of the dispersion. In areas of moderate to high relief the total uranium content of the stream sediment gives dispersion trains up to about 500 m from the mineralisation, and peak-to-background ratios of about 3. The use of cold-extractable uranium doubles the length of the dispersion, and peak-to-background ratios are greater than 10 and may be as high as 35. In areas of low relief, the total uranium content of the sediment gives low anomalies, with short dispersion downstream. Cold-extractable uranium gives anomalies 500-1 000 m from the mineralisation. This is interpreted to be due to the longer residence time of the clay minerals in the stream. In order to test the applicability of cold-extractable uranium on a regional scale, 720 samples were collected at a density of one sample per square kilometre. Statistical treatment of the data shows the U content of the stream sediments, to be log-normally distributed. For cold-extractable uranium, polymodal distributions, apparently representing background and anomalous samples, can be separated with a high rate of success, and meaningful threshold values can be assigned. This is not the case for the total uranium content of the stream sediments [af

The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study

DEFF Research Database (Denmark)

Bonaglia, Stefano; Hylén, Astrid; Rattray, Jane E.

2017-01-01

Given the increasing impacts of human activities on global nitrogen (N) cycle, investigations on N transformation processes in the marine environment have drastically increased in the last years. Benthic N cycling has mainly been studied in anthropogenically impacted estuaries and coasts, while its...... sediments worldwide (range 34–344 µmol N m−2 d−1). Anammox accounted for 18–26 % of the total N2 production. Absence of free hydrogen sulfide and low concentrations of dissolved iron in sediment pore waters suggested that denitrification and DNRA were driven by organic matter oxidation rather than...... chemolithotrophy. DNRA was as important as denitrification at a shallow, coastal station situated in the northern Bothnian Bay. At this pristine and fully oxygenated site, ammonium regeneration through DNRA contributed more than one third to the total dissolved nitrogen (TDN) diffusing from the sediment...

Characteristics of Sediment Transportation in Two Contrasting Oak Forested Watersheds in the Lesser Central Himalaya, India

Science.gov (United States)

Qazi, N. U. Q.; Bruijnzeel, S., Sr.; Rai, S. P., Sr.

2015-12-01

Sediment transfer from mountainous areas to lowland areas is one of the most important geomorphological processes globally with the bulk of the sediment yield from such areas typically deriving from mass wastage processes. This study presents monthly, seasonal and annual variations in sediment transport (both suspended load and bedload) as well as dissolved loads over three consecutive water years (2008-2011) for two small forested watersheds with contrasting levels of forest disturbance in the Lesser Himalaya of Northwest India. Seasonal and annual suspended sediment yields were strongly influenced by amounts of rainfall and streamflow and showed a 10-63 fold range between wet and dry years. Of the annual load, some 93% was produced on average during the monsoon season (June-September). Sediment production by the disturbed forest catchment was 1.9-fold (suspended sediment) to 5.9-fold (bedload) higher than that for the well-stocked forest catchment. By contrast, dissolved loads varied much less between years, seasons (although minimal during the dry summer season), and degree of forest disturbance. Total mechanical denudation rates were 1.6 times and 4.6 times larger than chemical denudation rates for the little disturbed and the heavily disturbed forest catchment, respectively whereas overall denudation rates were estimated at 0.69 and 1.04 mm per 1000 years, respectively.

Sediment Budgets and Sources Inform a Novel Valley Bottom Restoration Practice Impacted by Legacy Sediment: The Big Spring Run, PA, Restoration Experiment

Science.gov (United States)

Walter, R. C.; Merritts, D.; Rahnis, M. A.; Gellis, A.; Hartranft, J.; Mayer, P. M.; Langland, M.; Forshay, K.; Weitzman, J. N.; Schwarz, E.; Bai, Y.; Blair, A.; Carter, A.; Daniels, S. S.; Lewis, E.; Ohlson, E.; Peck, E. K.; Schulte, K.; Smith, D.; Stein, Z.; Verna, D.; Wilson, E.

2017-12-01

Big Spring Run (BSR), a small agricultural watershed in southeastern Pennsylvania, is located in the Piedmont Physiographic Province, which has the highest nutrient and sediment yields in the Chesapeake Bay watershed. To effectively reduce nutrient and sediment loading it is important to monitor the effect of management practices on pollutant reduction. Here we present results of an ongoing study, begun in 2008, to understand the impact of a new valley bottom restoration strategy for reducing surface water sediment and nutrient loads. We test the hypotheses that removing legacy sediments will reduce sediment and phosphorus loads, and that restoring eco-hydrological functions of a buried Holocene wetland (Walter & Merritts 2008) will improve surface and groundwater quality by creating accommodation space to trap sediment and process nutrients. Comparisons of pre- and post-restoration gage data show that restoration lowered the annual sediment load by at least 118 t yr-1, or >75%, from the 1000 m-long restoration reach, with the entire reduction accounted for by legacy sediment removal. Repeat RTK-GPS surveys of pre-restoration stream banks verified that >90 t yr-1 of suspended sediment was from bank erosion within the restoration reach. Mass balance calculations of 137Cs data indicate 85-100% of both the pre-restoration and post-restoration suspended sediment storm load was from stream bank sources. This is consistent with trace element data which show that 80-90 % of the pre-restoration outgoing suspended sediment load at BSR was from bank erosion. Meanwhile, an inventory of fallout 137Cs activity from two hill slope transects adjacent to BSR yields average modern upland erosion rates of 2.7 t ha-1 yr-1 and 5.1 t ha-1 yr-1, showing modest erosion on slopes and deposition at toe of slopes. We conclude that upland farm slopes contribute little soil to the suspended sediment supply within this study area, and removal of historic valley bottom sediment effectively

Sediment and nutrient modeling for TMDL development and implementation

OpenAIRE

Borah, D. K.; Yagow, G.; Saleh, A.; Barnes, P. L.; Rosenthal, W.; Krug, E. C.; Hauck, L. M.

2006-01-01

At present, there are over 34,000 impaired waters and over 58,000 associated impairments officially listed in the U.S. Nutrients and sediment are two of the most common pollutants included in the list. States are required to identify and list those waters within their boundaries that are not meeting standards, to prioritize them, and to develop Total Maximum Daily Loads (TMDLs) for the pollutants of concern. Models are used to support development of TMDLs, typically to estimate source loading...

Influence of turbulence on bed load sediment transport

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Chua, L.; Cheng, N. S.

2003-01-01

This paper summarizes the results of an experimental study on the influence of an external turbulence field on the bedload sediment transport in an open channel. The external turbulence was generated by: (1) with a horizontal pipe placed halfway through the depth, h; (2) with a series of grids......-bed experiments and the ripple-covered-bed experiments. In the former case, the flow in the presence of the turbulence generator was adjusted so that the mean bed shear stress was the same as in the case without the turbulence generator in order to single out the effect of the external turbulence on the sediment...... correlated with the sediment transport rate. The sediment transport increases markedly with increasing turbulence level....

Sediment transport dynamics in the Central Himalaya: assessing during monsoon the erosion processes signature in the daily suspended load of the Narayani river

Science.gov (United States)

Morin, Guillaume; Lavé, Jérôme; Lanord, Christian France; Prassad Gajurel, Ananta

2017-04-01

The evolution of mountainous landscapes is the result of competition between tectonic and erosional processes. In response to the creation of topography by tectonics, fluvial, glacial, and hillslope denudation processes erode topography, leading to rock exhumation and sediment redistribution. When trying to better document the links between climate, tectonic, or lithologic controls in mountain range evolution, a detailed understanding of the influence of each erosion process in a given environment is fundamental. At the scale of a whole mountain range, a systematic survey and monitoring of all the geomorphologic processes at work can rapidly become difficult. An alternative approach can be provided by studying the characteristics and temporal evolution of the sediments exported out of the range. In central Himalaya, the Narayani watershed presents contrasted lithologic, geochemical or isotopic signatures of the outcropping rocks as well as of the erosional processes: this particular setting allows conducting such type of approach by partly untangling the myopic vision of the spatial integration at the watershed scale. Based on the acquisition and analysis of a new dataset on the daily suspended load concentration and geochemical characteristics at the mountain outlet of one of the largest Himalayan rivers (drainage area = 30000 km2) bring several important results on Himalayan erosion, and on climatic and process controls. 1. Based on discrete depth sampling and on daily surface sampling of suspended load associated to flow characterization through ADCP measurements, we were first able to integrate sediment flux across a river cross-section and over time. We estimate for 2010 year an equivalent erosion rate of 1.8 +0.35/-0.2 mm/yr, and over the last 15 years, using past sediment load records from the DHM of Nepal, an equivalent erosion rate of 1.6 +0.3/-0.2 mm/yr. These rates are also in close agreement with the longer term ( 500 yrs) denudation rates of 1.7 mm

Water Discharge and Sediment Load Changes in China: Change Patterns, Causes, and Implications

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Chong Jiang

2015-10-01

Full Text Available In this research, monthly hydrological and daily meteorological data were collected across China for the period 1956–2012. Modified Mann–Kendall tests, double mass curve analysis, and correlation statistics were performed to identify the long-term trends and interrelation of the hydrometeorological variables and to examine the influencing factors of streamflow and sediment. The results are as follows: (1 In the last 60 years, the streamflow in northern China has shown different decreasing trends. For the southern rivers, the streamflow presented severe fluctuations, but the declining trend was insignificant. For the streamflow in western China, an increasing trend was shown. (2 In the northern rivers, the streamflow was jointly controlled by the East Asian monsoon and westerlies. In the southern rivers, the runoff was mainly influenced by the Tibet–Qinghai monsoon, the South Asian monsoon, and westerlies. (3 Sediment loads in the LCRB (Lancang River Basin and YZRB (Yarlung Zangbo River Basin did not present significant change trends, although other rivers showed different degrees of gradual reduction, particularly in the 2000s. (4 Underlying surface and precipitation changes jointly influenced the streamflow in eastern rivers. The water consumption for industrial and residential purposes, soil and water conservation engineering, hydraulic engineering, and underlying surface changes induced by other factors were the main causes of streamflow and sediment reduction.

Characterization of Dredged Sediments from Santander Bay

International Nuclear Information System (INIS)

Cortes, M.; Ibanez, R.; Viguri, J.R.; Irabien, A.

1999-01-01

The purpose of this study is the physico- chemical characterisation of Santander Bay (North Spain) inter-tidal sediments, with the determination of levels of selected organic compounds pollution. A sampling strategy has been developed based on characteristic parameters of the study. The physico-chemical seasonal characterisation of sediments has been performed by determination of waster content, Ph, density, humidity, lost on ignition (LOI), particle size distribution, and chemical analysis of three categories of organic compounds (VOCs,EOX and PAHs) selected for its ubiquity, persistence and high potential of environmental hazard. The EOX analysis give a picture of the total load of organo halogen compounds in the estuarine area and the VOC and ph values obtained, allow the characterization of sediments in two areas in function of the closeness to the urban and industrial activities

Constituent concentrations, loads, and yields to Beaver Lake, Arkansas, water years 1999-2008

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Bolyard, Susan E.; De Lanois, Jeanne L.; Green, W. Reed

2010-01-01

Beaver Lake is a large, deep-storage reservoir used as a drinking-water supply and considered a primary watershed of concern in the State of Arkansas. As such, information is needed to assess water quality, especially nutrient enrichment, nutrient-algal relations, turbidity, and sediment issues within the reservoir system. Water-quality samples were collected at three main inflows to Beaver Lake: the White River near Fayetteville, Richland Creek at Goshen, and War Eagle Creek near Hindsville. Water-quality samples collected over the period represented different flow conditions (from low to high). Constituent concentrations, flow-weighted concentrations, loads, and yields from White River, Richland Creek, and War Eagle Creek to Beaver Lake for water years 1999-2008 were documented for this report. Constituents include total ammonia plus organic nitrogen, dissolved nitrite plus nitrate nitrogen, dissolved orthophosphorus (soluble reactive phosphorus), total phosphorus, total nitrogen, dissolved organic carbon, total organic carbon, and suspended sediment. Linear regression models developed by computer program S-LOADEST were used to estimate loads for each constituent for the 10-year period at each station. Constituent yields and flow-weighted concentrations for each of the three stations were calculated for the study. Constituent concentrations and loads and yields varied with time and varied among the three tributaries contributing to Beaver Lake. These differences can result from differences in precipitation, land use, contributions of nutrients from point sources, and variations in basin size. Load and yield estimates varied yearly during the study period, water years 1999-2008, with the least nutrient and sediment load and yields generally occurring in water year 2006, and the greatest occurring in water year 2008, during a year with record amounts of precipitation. Flow-weighted concentrations of most constituents were greatest at War Eagle Creek near Hindsville

Comparison of total Hg results in sediment samples from Rio Grande reservoir determine by NAA and CV AAS

International Nuclear Information System (INIS)

Franklin, Robson L.

2011-01-01

The Rio Grande reservoir is located in the Metropolitan area of Sao Paulo and it is used for recreation purposes and as source water for drinking water production. During the last decades has been detected mercury contamination in the sediments of this reservoir, mainly in the eastern part, near the main affluent of the reservoir, in the Rio Grande da Serra and Ribeirao Pires counties. In the present study bottom sediment samples were collected in four different sites into four sampling campaigns during the period of September 2008 to January 2010. The samples were dried at room temperature, ground and passed through a 2 mm sieve. Total Hg determination in the sediment samples was carried out by two different analytical techniques: neutron activation analysis (NAA) and cold vapor atomic absorption spectrometry (CV AAS). The methodology validation, in terms of precision and accuracy, was performed by reference materials, and presented a recovery of 83 to 108%. The total Hg results obtained by both analytical techniques ranged from 3 to 71 mg kg-1 and were considered similar by statistical analysis, even though NAA technique furnishes the total concentration while CV AAS using the 3015 digestion procedure characterizes only the bioavailable Hg. These results confirm that both analytical techniques were suitable to detect the Hg concentration levels in the Rio Grande sediments studied. The Hg levels in the sediment of the Rio Grande reservoir confirm the anthropogenic origin for this element in this ecosystem. (author)

Determining the sources of fine-grained sediment using the Sediment Source Assessment Tool (Sed_SAT)

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Gorman Sanisaca, Lillian E.; Gellis, Allen C.; Lorenz, David L.

2017-07-27

A sound understanding of sources contributing to instream sediment flux in a watershed is important when developing total maximum daily load (TMDL) management strategies designed to reduce suspended sediment in streams. Sediment fingerprinting and sediment budget approaches are two techniques that, when used jointly, can qualify and quantify the major sources of sediment in a given watershed. The sediment fingerprinting approach uses trace element concentrations from samples in known potential source areas to determine a clear signature of each potential source. A mixing model is then used to determine the relative source contribution to the target suspended sediment samples.The computational steps required to apportion sediment for each target sample are quite involved and time intensive, a problem the Sediment Source Assessment Tool (Sed_SAT) addresses. Sed_SAT is a user-friendly statistical model that guides the user through the necessary steps in order to quantify the relative contributions of sediment sources in a given watershed. The model is written using the statistical software R (R Core Team, 2016b) and utilizes Microsoft Access® as a user interface but requires no prior knowledge of R or Microsoft Access® to successfully run the model successfully. Sed_SAT identifies outliers, corrects for differences in size and organic content in the source samples relative to the target samples, evaluates the conservative behavior of tracers used in fingerprinting by applying a “Bracket Test,” identifies tracers with the highest discriminatory power, and provides robust error analysis through a Monte Carlo simulation following the mixing model. Quantifying sediment source contributions using the sediment fingerprinting approach provides local, State, and Federal land management agencies with important information needed to implement effective strategies to reduce sediment. Sed_SAT is designed to assist these agencies in applying the sediment fingerprinting

Predicting future land cover change and its impact on streamflow and sediment load in a trans-boundary river basin

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J. Wang

2018-06-01

Full Text Available Sediment load can provide very important perspective on erosion of river basin. The changes of human-induced vegetation cover, such as deforestation or afforestation, affect sediment yield process of a catchment. We have already evaluated that climate change and land cover change changed the historical streamflow and sediment yield, and land cover change is the main factor in Red river basin. But future streamflow and sediment yield changes under potential future land cover change scenario still have not been evaluated. For this purpose, future scenario of land cover change is developed based on historical land cover changes and land change model (LCM. In addition, future leaf area index (LAI is simulated by ecological model (Biome-BGC based on future land cover scenario. Then future scenarios of land cover change and LAI are used to drive hydrological model and new sediment rating curve. The results of this research provide information that decision-makers need in order to promote water resources planning efforts. Besides that, this study also contributes a basic framework for assessing climate change impacts on streamflow and sediment yield that can be applied in the other basins around the world.

Statistically extracted fundamental watershed variables for estimating the loads of total nitrogen in small streams

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Kronholm, Scott C.; Capel, Paul D.; Terziotti, Silvia

2016-01-01

Accurate estimation of total nitrogen loads is essential for evaluating conditions in the aquatic environment. Extrapolation of estimates beyond measured streams will greatly expand our understanding of total nitrogen loading to streams. Recursive partitioning and random forest regression were used to assess 85 geospatial, environmental, and watershed variables across 636 small (monitoring may be beneficial.

Responses of streamflow and sediment load to climate change and human activity in the Upper Yellow River, China: a case of the Ten Great Gullies Basin.

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Liu, Tong; Huang, He Qing; Shao, Mingan; Yao, Wenyi; Gu, Jing; Yu, Guoan

2015-01-01

Soil erosion and land desertification are the most serious environmental problems globally. This study investigated the changes in streamflow and sediment load from 1964 to 2012 in the Ten Great Gullies area of the Upper Yellow River. Tests for gradual trends (Mann-Kendall test) and abrupt changes (Pettitt test) identify that significant declines in streamflow and sediment load occurred in 1997-1998 in two typical gullies. A comparison of climatic variability before and after the change points shows no statistically significant trends in annual precipitation and potential evapotranspiration. Human activities have been very active in the region and during 1990-2010, 146.01 and 197.62 km2 of land were converted, respectively, to forests and grassland, with corresponding increases of 87.56 and 77.05%. In addition, a large number of check dams have been built up in the upper reaches of the ten gullies. These measures were likely responsible for the significant decline in the annual streamflow and sediment load over the last 49 years.

Geochemical loading of suspended sediment carried by large monsoonal rivers in Burma

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Robinson, R. A.; Tipper, E.; Bird, M. I.; Oo, N.

2013-12-01

The Irrawaddy and Salween rivers of Burma drain the most rapidly exhuming region in the Himalayas, the eastern syntaxis zone. These monsoonal rivers have catchment areas of 0.413 x 106 km2 and 0.272 x 106 km2, respectively, and approximately 95% of the Irrawaddy catchment lies within Burma, while the catchment of the Salween flows through China, Thailand and Burma. They are long rivers (~2000 and ~2800 km) which have steep and narrow bedrock gorges along much of their length, and different amounts of floodplain in their lower reaches. These rivers have been less studied than other large Asian systems because of political instability in Burma and restricted access. Based on available historical data, and field work in 2005-2008, Robinson et al. (2007) estimated that the Irrawaddy is likely to be the 3rd largest river globally in terms of sediment load and when the Irrawaddy and Salween estimated fluxes are combined, they together contribute 4.6 Mt/yr of particulate organic carbon (POC) and an additional 1.1Mt/yr of dissolved organic carbon (DOC) to the ocean. When estimated yields of total organic carbon are calculated, the Irrawaddy-Salween system ranks alongside the Amazon as one of the largest yields of organic carbon, and is higher than the yield for the Ganges-Brahmaptura (Bird et al., 2008). Here we present preliminary geochemical data for water and sediment from the Irrawaddy and Salween rivers, and demonstrate the variability in elemental concentrations of water between the rivers and the summer and winter monsoon seasons, and differences in suspended sediment geochemistry as a function of water depth. The variability and magnitude of weathering products carried by such significant systems need to be quantified in order to understand their contribution to global element cycling (Tipper et al., 2006) and sedimentary depocentres. Our data highlight that further study of the geochemistry of such large rivers will significantly improve our understanding of the

Sedimentation and occurrence and trends of selected nutrients, other chemical constituents, and cyanobacteria in bottom sediment, Clinton Lake, northeast Kansas, 1977-2009

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Juracek, Kyle E.

2011-01-01

A combination of available bathymetric-survey information and bottom-sediment coring was used to investigate sedimentation and the occurrence of selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 25 trace elements, cyanobacterial akinetes, and the radionuclide cesium-137 in the bottom sediment of Clinton Lake, northeast Kansas. The total estimated volume and mass of bottom sediment deposited from 1977 through 2009 in the conservation (multi-purpose) pool of the reservoir was 438 million cubic feet and 18 billion pounds, respectively. The estimated sediment volume occupied about 8 percent of the conservation-pool, water-storage capacity of the reservoir. Sedimentation in the conservation pool has occurred about 70 percent faster than originally projected at the time the reservoir was completed. Water-storage capacity in the conservation pool has been lost to sedimentation at a rate of about 0.25 percent annually. Mean annual net sediment deposition since 1977 in the conservation pool of the reservoir was estimated to be 563 million pounds per year. Mean annual net sediment yield from the Clinton Lake Basin was estimated to be 1.5 million pounds per square mile per year. Typically, the bottom sediment sampled in Clinton Lake was at least 99 percent silt and clay. The mean annual net loads of total nitrogen and total phosphorus deposited in the bottom sediment of Clinton Lake were estimated to be 1.29 million pounds per year and 556,000 pounds per year, respectively. The estimated mean annual net yields of total nitrogen and total phosphorus from the Clinton Lake Basin were 3,510 pounds per square mile per year and 1,510 pounds per square mile per year, respectively. Throughout the history of Clinton Lake, total nitrogen concentrations in the deposited sediment generally were uniform and indicated consistent inputs to the reservoir over time. Likewise, total phosphorus concentrations in the deposited sediment generally were uniform

Climate Change on Discharge and Sedimentation of River Awara, Nigeria

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Philipa O. Idogho

2014-07-01

Full Text Available The dynamics of variation in effect of climate change on discharges and sedimentation mechanism of River Awara is investigated using 14-year data of rainfall (mm, discharges (m 3 /s, temperature ( 0 c and sediment load (t. Surface runoff (mm was computed using Water Balance Equation and some other empirical iteration based on the observed rainfall and temperature over a period of time. Analysis of Paired Sample reveals the relationship between tested hydrological variables: Rainfall-Runoff; Runoff-Sediment load; and DischargeSediment load are significant at 0.95 level of confidence interval. Logarithm calibration curve further illustrates that Rainfall-Runoff and Runoff-Sediment have coefficient values (R 2 of 0.996 and 0.822 respectively. Analytical iteration shows that the intensity and duration of precipitation determine the magnitude of river, generation of surface runoff and sedimentation rate. Increase in rainfall depth by 100 mm within the 14-year has resulted to serious erodobility and erositivity around River Awara. Cumulative average sediment load ratio of 0.46 has significantly reduced the reservoir capacity of the river by 10%. 78% of total annual surface runoff is lost to ocean; since reservoir capacity has been silted up which in turns reduces the volume of water that could be held for storage, treatment and distribution for its intended purposes. Comparative physics-based output indicates that temperature increase of 0.7 0 c between 1997 and 2004, due to internal processes of the Earth and some human activities. It is however projected that temperature will rise by 0.9 0 c by the end of 2015. Projected rise in temperature will adversely affect hydrological cycle and complicate already scarce-water resources due to intensive evapotranspiration, infiltration and reduction in stream flow. Holistic integration using bottom-up mechanism needs to be applied to address this constraint. Dredging of river Awara is very important to enhance

Topographic filtering simulation model for sediment source apportionment

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Cho, Se Jong; Wilcock, Peter; Hobbs, Benjamin

2018-05-01

We propose a Topographic Filtering simulation model (Topofilter) that can be used to identify those locations that are likely to contribute most of the sediment load delivered from a watershed. The reduced complexity model links spatially distributed estimates of annual soil erosion, high-resolution topography, and observed sediment loading to determine the distribution of sediment delivery ratio across a watershed. The model uses two simple two-parameter topographic transfer functions based on the distance and change in elevation from upland sources to the nearest stream channel and then down the stream network. The approach does not attempt to find a single best-calibrated solution of sediment delivery, but uses a model conditioning approach to develop a large number of possible solutions. For each model run, locations that contribute to 90% of the sediment loading are identified and those locations that appear in this set in most of the 10,000 model runs are identified as the sources that are most likely to contribute to most of the sediment delivered to the watershed outlet. Because the underlying model is quite simple and strongly anchored by reliable information on soil erosion, topography, and sediment load, we believe that the ensemble of simulation outputs provides a useful basis for identifying the dominant sediment sources in the watershed.

Analysis of heavy metals in road-deposited sediments.

Science.gov (United States)

Herngren, Lars; Goonetilleke, Ashantha; Ayoko, Godwin A

2006-07-07

Road-deposited sediments were analysed for heavy metal concentrations at three different landuses (residential, industrial, commercial) in Queensland State, Australia. The sediments were collected using a domestic vacuum cleaner which was proven to be highly efficient in collecting sub-micron particles. Five particle sizes were analysed separately for eight heavy metal elements (Zn, Fe, Pb, Cd, Cu, Cr, Al and Mn). At all sites, the maximum concentration of the heavy metals occurred in the 0.45-75 microm particle size range, which conventional street cleaning services do not remove efficiently. Multicriteria decision making methods (MCDM), PROMETHEE and GAIA, were employed in the data analysis. PROMETHEE, a non-parametric ranking analysis procedure, was used to rank the metal contents of the sediments sampled at each site. The most polluted site and particle size range were the industrial site and the 0.45-75 microm range, respectively. Although the industrial site displayed the highest metal concentrations, the highest heavy metal loading coincided with the highest sediment load, which occurred at the commercial site. GAIA, a special form of principal component analysis, was applied to determine correlations between the heavy metals and particle size ranges and also to assess possible correlation with total organic carbon (TOC). The GAIA-planes revealed that irrespective of the site, most of the heavy metals are adsorbed to sediments below 150 microm. A weak correlation was found between Zn, Mn and TOC at the commercial site. This could lead to higher bioavailability of these metals through complexation reactions with the organic species in the sediments.

Floodplains as a source of fine sediment in grazed landscapes: Tracing the source of suspended sediment in the headwaters of an intensively managed agricultural landscape

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Yu, Mingjing; Rhoads, Bruce L.

2018-05-01

The flux of fine sediment within agricultural watersheds is an important factor determining the environmental quality of streams and rivers. Despite this importance, the contributions of sediment sources to suspended sediment loads within intensively managed agricultural watersheds remain poorly understood. This study assesses the provenance of fine suspended sediment in the headwater portion of a river flowing through an agricultural landscape in Illinois. Sediment source samples were collected from five sources: croplands, forested floodplains, grasslands, upper grazed floodplains, and lower grazed floodplains. Event-based and aggregated suspended sediment samples were collected from the stream at the watershed outlet. Quantitative geochemical fingerprinting techniques and a mixing model were employed to estimate the relative contributions of sediment from the five sources to the suspended sediment loads. To account for possible effects of small sample sizes, the analysis was repeated with only two sources: grazed floodplains and croplands/grasslands/forested floodplains. Results based on mean values of tracers indicate that the vast majority of suspended sediment within the stream (>95%) is derived from erosion of channel banks and the soil surface within areas of grazed floodplains. Uncertainty analysis based on Monte Carlo simulations indicates that mean values of tracer properties, which do not account for sampling variability in these properties, probably overestimate contributions from the two major sources. Nevertheless, this analysis still supports the conclusion that floodplain erosion accounts for the largest percentage of instream sediment (≈55-75%). Although grazing occurs over only a small portion of the total watershed area, grazed floodplains, which lie in close proximity to the stream channel, are an important source of sediment in this headwater steam system. Efforts to reduce fluxes of fine sediment in this intensively managed landscape should

Automated Measurement for Sensitivity Analysis of Runoff-Sediment Load at Varying Surface Gradients

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Imanogor P.A.

2015-07-01

Full Text Available Direct measurement of surface runoff is often associated with errors and inaccuracies which results to unreliable hydrological data. An automatic Runoff-meter using tipping buckets arrangement calibrated to tip 0.14 liter of runoff water per tip with an accuracy of ± 0.001 litre was used to measure surface runoff from a steel bounded soil tray of dimension (1200 mm X 900 mm X 260 mm filled with sand loamy to the depth of 130 mm and inclined at angle (0 0 , 5 0 ,12 0 and 15 0 horizontal to the instrument. The effect of varying angles of inclination on runoff intensity, sediment loss rate and sediment loss is significant at 5 % confidence level, while surface runoff is not significant at 5 % confidence level. Total highest sediment loss of 458.2 g and 313.4 g were observed at angle 15 0 and 12 0 respectively. Total surface runoff of 361.5 mm and 445.8 mm were generated at inclined angle of 0 0 and 5 0 , while at angle 12 0 and 15 0 , 564.3 mm and 590.0 mm of surface runoff were generated. In addition, runoff intensity and sediment loss rate were highest at angle 15 0 , while the lowest values of 1.5mm/min and 5.43 g/min were obtained at angle of inclination 5 0 . The results showed that strong relationship existed among the hydrological variables as a result of subjecting the steel bounded soil tray to different angles of inclination. Such results would provide useful data for the running of physics-based deterministic model of surface runoff and erosion which will be useful for the design of hydrological structures, land use planning and management.

Distribution of surficial sediment in Long Island Sound and adjacent waters: Texture and total organic carbon

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Poppe, L.J.; Knebel, H.J.; Mlodzinska, Z.J.; Hastings, M.E.; Seekins, B.A.

2000-01-01

The surficial sediment distribution within Long Island Sound has been mapped and described using bottom samples, photography, and sidescan sonar, combined with information from the geologic literature. The distributions of sediment type and total organic carbon (TOC) reveal several broad trends that are largely related to the sea-floor geology, the bathymetry, and the effects of modern tidal- and wind-driven currents. Sediment types are most heterogeneous in bathymetrically complex and shallow nearshore areas; the heterogeneity diminishes and the texture fines with decreasing bottom-current energy. Lag deposits of gravel and gravelly sand dominate the surficial sediment texture in areas where bottom currents are the strongest (such as where tidal flow is constricted) and where glacial till crops out at the sea floor. Sand is the dominant sediment type in areas characterized by active sediment transport and in shallow areas affected by fine-grained winnowing. Silty sand and sand-silt-clay mark transitions within the basin from higher- to lower-energy environments, suggesting a diminished hydraulic ability to sort and transport sediment. Clayey silt and silty clay are the dominant sediment types accumulating in the central and western basins and in other areas characterized by long-term depositional environments. The amount of TOC in the sediments of Long Island Sound varies inversely with sediment grain size. Concentrations average more than 1.9% (dry weight) in clayey silt, but are less than 0.4% in sand. Generally, values for TOC increase both toward the west in the Sound and from the shallow margins to the deeper parts of the basin floor. Our data also suggest that TOC concentrations can vary seasonally.

Watershed and discharge influences on the phase distribution and tributary loading of total mercury and methylmercury into Lake Superior

International Nuclear Information System (INIS)

Babiarz, Christopher; Hoffmann, Stephen; Wieben, Ann; Hurley, James; Andren, Anders; Shafer, Martin; Armstrong, David

2012-01-01

Knowledge of the partitioning and sources of mercury are important to understanding the human impact on mercury levels in Lake Superior wildlife. Fluvial fluxes of total mercury (Hg T ) and methylmercury (MeHg) were compared to discharge and partitioning trends in 20 sub-basins having contrasting land uses and geological substrates. The annual tributary yield was correlated with watershed characteristics and scaled up to estimate the basin-wide loading. Tributaries with clay sediments and agricultural land use had the largest daily yields with maxima observed near the peak in water discharge. Roughly 42% of Hg T and 57% of MeHg was delivered in the colloidal phase. Tributary inputs, which are confined to near-shore zones of the lake, may be more important to the food-web than atmospheric sources. The annual basin-wide loading from tributaries was estimated to be 277 kg yr −1 Hg T and 3.4 kg yr −1 MeHg (5.5 and 0.07 mg km −2 d −1 , respectively). - Highlights: ► The highest mercury yields occurred during spring melt except in forested watersheds. ► Roughly half of the mercury yield occurred in the colloidal phase. ► About 277 kg of Hg T and 3.4 kg of MeHg were delivered annually via tributaries. ► Whole-water MeHg loading was roughly equivalent to the estimated atmospheric loading. ► Watersheds with peat, loam or sandy soils deliver more MeHg than those with clays. - Tributary inputs, which are confined to the near-shore zones of Lake Superior, provide more mercury to these sensitive aquatic habitats than direct atmospheric deposition.

Estimating sediment and caesium-137 fluxes in the Ribble Estuary through time-series airborne remote sensing

International Nuclear Information System (INIS)

Wakefield, R.; Tyler, A.N.; McDonald, P.; Atkin, P.A.; Gleizon, P.; Gilvear, D.

2011-01-01

High spatial and temporal resolution airborne imagery were acquired for the Ribble Estuary, North West England in 1997 and 2003, to assess the application of time-series airborne remote sensing to quantify total suspended sediment and radionuclide fluxes during a flood and ebb tide sequence. Concomitant measurements of suspended particulate matter (SPM) and water column turbidity were obtained during the time-series image acquisition for the flood and ebb tide sequence on the 17th July 2003 to verify the assumption of a vertically well mixed estuary and thus justifying the vertical extrapolation of spatially integrated estimate of surface SPM. The 137 Cs activity concentrations were calculated from a relatively stable relationship between SPM and 137 Cs for the Ribble Estuary. Total estuary wide budgets of sediment and 137 Cs were obtained by combining the image-derived estimates of surface SPM and 137 Cs with estimates of water volume from a two-dimensional hydrodynamic model (VERSE) developed for the Ribble Estuary. These indicate that around 10,000 tonnes of sediment and 2.72 GBq of 137 Cs were deposited over the tidal sequence monitored in July 2003. This compared favourably with bed height elevation change estimated from field work. An uncertainty analysis on the total sediment and 137 Cs flux yielded a total budget of the order of 40% on the final estimate. The results represent a novel approach to providing a spatially integrated estimate of the total net sediment and radionuclide flux in an intertidal environment over a flood and ebb tide sequence. - Research highlights: → This paper provides a rare insight into the next flux of sediment and associated radionuclide loading into an estuary over and ebb and flood tide sequence. → The paper uses high temporal resolution airborne imagery coupled with concomitant sampling to convert total suspended sediment flux to 137 Cs loading. → For the estuary and date studied, it is estimate that an 10,000 tonnes of

Temporal changes in TBT pollution in water, sediment, and oyster from Jinhae Bay after the total ban in South Korea.

Science.gov (United States)

Kim, Nam Sook; Hong, Sang Hee; Yim, Un Hyuk; Shin, Kyung-Hoon; Shim, Won Joon

2014-09-15

Temporal change in tributyltin (TBT) levels in Jinhae Bay, which has various TBT sources, was investigated in water, sediments, and oysters from 2003 to 2013 after its total ban in South Korea. The seawater TBT levels decreased over 500-fold from 1995/97 to 2008/09. The oyster TBT levels were about fourfold lower in 2012/13 than in 1995/97. However, the sediment TBT levels did not significantly change, even 10 years after the partial TBT ban on small ships and 7 years after the total TBT ban on all oceangoing vessels in Korea. The total ban of TBT use effectively reduced water and oyster TBT levels in Jinhae Bay, but TBT levels in water, oysters, and sediment remained above the global environmental quality standards established to protect marine organisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Composition and Environmental Effects of LFOM and HFOM in "Incense-Ash" Sediments of West Lake, Hangzhou, China].

Science.gov (United States)

Li, Jing; Zhu, Guang-wei; Zhu, Meng-yuan; Gong, Zhi-jun; Xu, Hai; Yang, Gui-jun

2015-06-01

To understand the organic matter pollution characteristic and its relationship with nitrogen, phosphorus and other nutrients in sediments of high organic matter type of urban shallow lakes, the organic matter content, light fraction organic matter (LFOM), heavy fraction organic matter (HFOM), and nitrogen and phosphorus contents were investigated in eight different regions of West Lake, Hangzhou. The results showed that, the organic matter content of the west lake sediment was 28-251 g x kg(-1), belonging to typical high organic matter sediment. The difference of organic matter content in different lake sediments was very big. The sediments located at the input site of water diversion engineering had significantly lower organic content than the rest regions. The LFOM content of West Lake sediment ranged 0.57-9.17 g x kg(-1), which averagely occupied 2.83% of the total organic matter, and the HFOM content ranged 5.35-347.41 g x kg(-1), which occupied more than 90% of the total organic matter. Compared to other shallow lakes located in China, sediments of West Lake had significantly high percentage of HFOM/LFOM ratio. But the HFOM content was obviously on the high side, reflecting the west lake as an urban lake with a long history, as well as high organic matter pollution load and sediment humification degree. Both the content and the ratio of LFOM/HFOM in sediment were related to nitrogen and phosphorus contents in sediment. This suggested that the composition of organic matter in West Lake sediments had potential control ability for the internal loading of N and P of the lake.

Transport of sediments, carbon and nutrients in areas of reforestation and grassland based on simulated rainfall

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Adilson Pinheiro

2013-08-01

Full Text Available The objective of this study was to evaluate the soil losses, as well as carbon and chemical samples in runoff through areas of pine (Pinus taeda, eucalyptus (Eucalyptus dunni and a consortium of pasture with oat (Avena stringosa and ryegrass (Lolium multiflorium in the Fragosos river basin, in Concordia, SC. For this, rainfall simulations with mean intensities of 94 mm h-1 were conducted in September and November 2011, in plots of 1 m2 established in the three areas. Runoff, loads carried of the sediment, and carbon and chemical concentrations were quantified in the experiment. The results showed that the concentrations of sediment and organic carbon were higher in the eucalyptus area. The largest concentrations of chemicals for all areas were nitrate, calcium, magnesium and potassium. Total carbon, organic carbon, sediment and nitrate were transported in higher loads in the eucalyptus area. With the exception of nitrate and chloride, the chemical loads carried were higher in the pasture area.

Satellite Derived Water Quality Observations Are Related to River Discharge and Nitrogen Loads in Pensacola Bay, Florida

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John C. Lehrter

2017-09-01

Full Text Available Relationships between satellite-derived water quality variables and river discharges, concentrations and loads of nutrients, organic carbon, and sediments were investigated over a 9-year period (2003–2011 in Pensacola Bay, Florida, USA. These analyses were conducted to better understand which river forcing factors were the primary drivers of estuarine variability in several water quality variables. Remote sensing reflectance time-series data were retrieved from the MEdium Resolution Imaging Spectrometer (MERIS and used to calculate monthly and annual estuarine time-series of chlorophyll a (Chla, colored dissolved organic matter (CDOM, and total suspended sediments (TSS. Monthly MERIS Chla varied from 2.0 mg m−3 in the lower region of the bay to 17.2 mg m−3 in the upper bay. MERIS CDOM and TSS exhibited similar patterns with ranges of 0.51–2.67 (m−1 and 0.11–8.9 (g m−3. Variations in the MERIS-derived monthly and annual Chla, CDOM, and TSS time-series were significantly related to monthly and annual river discharge and loads of nitrogen, organic carbon, and suspended sediments from the Escambia and Yellow rivers. Multiple regression models based on river loads (independent variables and MERIS Chla, CDOM, or TSS (dependent variables explained significant fractions of the variability (up to 62% at monthly and annual scales. The most significant independent variables in the regressions were river nitrogen loads, which were associated with increased MERIS Chla, CDOM, and TSS concentrations, and river suspended sediment loads, which were associated with decreased concentrations. In contrast, MERIS water quality variations were not significantly related to river total phosphorus loads. The spatially synoptic, nine-year satellite record expanded upon the spatial extent of past field studies to reveal previously unseen system-wide responses to river discharge and loading variation. The results indicated that variations in Pensacola Bay Chla

An update of the sediment fluxes investigation in the Rio Cordon (Italy after 25 years of monitoring

Directory of Open Access Journals (Sweden)

Lorenzo Picco

2012-12-01

Full Text Available Quantification of bed-load transport in high-gradient mountain streams is important, but the field data needed to test transport models are scarce and difficult to obtain. In the present study, we describe the experimental station for monitoring water and sediment fluxes built in 1985 on the Rio Cordon, a small step-pool channel in the eastern Italian Alps. The measuring station consists of an inclined frame that separates fine from coarse sediments (D>20 mm, which are continuously measured by a series of ultrasonic sensors fitted above a storage area. The acquired 25-year dataset, which comprises a high-magnitude/ low-recurrence flood event, has allowed a magnitude-frequency analysis of bed-load volumes to be performed. Results from a combined frequency analysis of peak water discharge and total bed-load volumes are presented. In addition, the integration between the sediment transport dataset and the repeated surveys of sediment sources and of channel changes allowed us to assess the geomorphological effectiveness of different flood events. Despite the importance of the experimental station for making these bed-load observations possible, its maintenance costs are not low and these may have an impact on its future existence. At the same time, improving current instrumentation and future installations with novel technology would make the station an ideal location for calibrating surrogate techniques for sediment transport monitoring.

Kinematic evaluation of patients with total and reverse shoulder arthroplasty during rehabilitation exercises with different loads.

Science.gov (United States)

de Toledo, Joelly Mahnic; Loss, Jefferson Fagundes; Janssen, Thomas W; van der Scheer, Jan W; Alta, Tjarco D; Willems, W Jaap; Veeger, DirkJan H E J

2012-10-01

Following shoulder arthroplasty, any well-planned rehabilitation program should include muscle strengthening. However, it is not always clear how different external loads influence shoulder kinematics in patients with shoulder prostheses. The objective of this study was to describe shoulder kinematics and determine the contribution of the scapulothoracic joint to total shoulder motion of patients with total and reverse shoulder arthroplasties and of healthy individuals during rehabilitation exercises (anteflexion and elevation in the scapular plane) using different loading conditions (without external load, 1 kg and elastic resistance). Shoulder motions were measured using an electromagnetic tracking device. A force transducer was used to record force signals during loaded conditions using elastic resistance. Statistical comparisons were made using a three-way repeated-measures analysis of variance with a Bonferroni post hoc testing. The scapula contributed more to movement of the arm in subjects with prostheses compared to healthy subjects. The same applies for loaded conditions (1 kg and elastic resistance) relative to unloaded tasks. For scapular internal rotation, upward rotation and posterior tilt no significant differences among groups were found during both exercises. Glenohumeral elevation angles during anteflexion were significantly higher in the total shoulder arthroplasty group compared to the reverse shoulder arthroplasty group. Differences in contribution of the scapula to total shoulder motion between patients with different types of arthroplasties were not significant. However, compared to healthy subjects, they were. Furthermore, scapular kinematics of patients with shoulder arthroplasty was influenced by implementation of external loads, but not by the type of load. Copyright © 2012 Elsevier Ltd. All rights reserved.

Preliminary studies of the total cation exchange capacity of sediments from two North Atlantic study sites

International Nuclear Information System (INIS)

Hydes, D.J.; Hill, N.C.; Clarke, H.; Carpenter, M.S.N.

1983-01-01

Initially four different methods of measuring total cation exchange capacity were compared. There were two chemical methods (ammonium saturation with displacement into seawater, and barium saturation followed by replacement with magnesium) and two radiochemical methods (sodium-22 and caesium-134 saturation). The barium-magnesium and sodium-22 methods were then applied to sediment samples from Core D10164Pound1K from the Nares Fracture Valley, and Core D10554Pound11K from the eastern flank of the Great Meteor Rise. The material at site 10164 is a pelagic clay whereas at site 10554 it is carbonate ooze. The total cation exchange capacities (T.C.E.C.) of samples from the two sites are similar when measured by the sodium-22 method, the mean for Core 10164 was 21.7 meq/100g and 24.4 meq/100g for Core 10554. However for Core 10554 the barium-magnesium method gives a mean of 42.8 meq/100g. The difference in T.C.E.C. measured by the two methods appears to be due to the high calcite content of core 10554 sediment. Measured exchange capacities are lower than in coastal sediments. In deep sea sediments organic matter either makes a very small contribution to the T.C.E.C. (core 10164) or actually blocks exchange sites (Core 10554). Amorphous oxides of iron and manganese contribute between 20 and 50% of the T.C.E.C. (author)

Influences of channelization on discharge of suspended sediment and wetland vegetation in Kushiro Marsh, northern Japan

Science.gov (United States)

Nakamura, Futoshi; Sudo, Tadashi; Kameyama, Satoshi; Jitsu, Mieko

1997-03-01

The effects of wetlands on hydrology, water quality, and wildlife habitat are internationally recognized. Protecting the remaining wetlands is one of the most important environmental issues in many countries. However wetlands in Japan have been gradually shrinking due to agricultural development and urbanization, which generally lowers the groundwater level and introduces suspended sediment and sediment-associated nutrients into wetlands. We examined the influences of channelization on discharge of suspended sediment and wetland vegetation in Hokkaido, northern Japan. The impact of river channelization was confirmed not only by the sediment budgets but also by river aggradation or degradation after the channelization and by the resultant vegetational changes. The budgets of suspended sediment demonstrated that wash load was the predominant component accounting for 95% of the total suspended load delivered into the wetland. This suspended sediment was primarily transported into the wetland by flooding associated with heavy rainfall. Twenty-three percent of the wash load and 63% of the suspended bed material load were deposited in the channelized reach, which produced aggradation of about 2 m at the end of the reach. A shorting of the length of the channel, due to channelization of a meandering river, steepened the slope and enhanced the stream power to transport sediment. This steepening shifted the depositional zones of fine sediment 5 km downstream and aggraded the riverbed. Development of the watershed may increase not only the water discharge but also the amount of suspended sediments. The aggradation reduced the carrying capacity of the channel and caused sediment ladened water to flood over the wetlands. The fine sediment accumulated on the wetlands gradually altered the edaphic conditions and wetland vegetation. A low percentage (10 to 15%) of organic contents of wetlands' soil is more evidence indicating that the present condition is far different from

Sediment filtration can reduce the N load of the waste water discharge - a full-scale lake experiment

Science.gov (United States)

Aalto, Sanni L.; Saarenheimo, Jatta; Karvinen, Anu; Rissanen, Antti J.; Ropponen, Janne; Juntunen, Janne; Tiirola, Marja

2016-04-01

European commission has obliged Baltic states to reduce nitrate load, which requires high investments on the nitrate removal processes and may increase emissions of greenhouse gases, e.g. N2O, in the waste water treatment plants. We used ecosystem-scale experimental approach to test a novel sediment filtration method for economical waste water N removal in Lake Keurusselkä, Finland between 2014 and 2015. By spatially optimizing the waste water discharge, the contact area and time of nitrified waste water with the reducing microbes of the sediment was increased. This was expected to enhance microbial-driven N transformation and to alter microbial community composition. We utilized 15N isotope pairing technique to follow changes in the actual and potential denitrification rates, nitrous oxide formation and dissimilatory nitrate reduction to ammonium (DNRA) in the lake sediments receiving nitrate-rich waste water input and in the control site. In addition, we investigated the connections between observed process rates and microbial community composition and functioning by using next generation sequencing and quantitative PCR. Furthermore, we estimated the effect of sediment filtration method on waste water contact time with sediment using the 3D hydrodynamic model. We sampled one year before the full-scale experiment and observed strong seasonal patterns in the process rates, which reflects the seasonal variation in the temperature-related mixing patterns of the waste water within the lake. During the experiment, we found that spatial optimization enhanced both actual and potential denitrification rates of the sediment. Furthermore, it did not significantly promote N2O emissions, or N retention through DNRA. Overall, our results indicate that sediment filtration can be utilized as a supplemental or even alternative method for the waste water N removal.

Variability of bed mobility in natural, gravel-bed channels and adjustments to sediment load at local and reach scales

Science.gov (United States)

Thomas E. Lisle; Jonathan M. Nelson; John Pitlick; Mary Ann Madej; Brent L. Barkett

2000-01-01

Abstract - Local variations in boundary shear stress acting on bed-surface particles control patterns of bed load transport and channel evolution during varying stream discharges. At the reach scale a channel adjusts to imposed water and sediment supply through mutual interactions among channel form, local grain size, and local flow dynamics that govern bed mobility...

Geomorphic analysis of the river response to sedimentation downstream of Mount Rainier, Washington

Science.gov (United States)

Czuba, Jonathan A.; Magirl, Christopher S.; Czuba, Christiana R.; Curran, Christopher A.; Johnson, Kenneth H.; Olsen, Theresa D.; Kimball, Halley K.; Gish, Casey C.

2012-01-01

from the mountain indicates that rockfalls, glaciers, debris flows, and main-stem flooding act sequentially to deliver sediment from Mount Rainier to river reaches in the Puget Lowland over decadal time scales. Greater-than-normal runoff was associated with cool phases of the Pacific Decadal Oscillation. Streamflow-gaging station data from four unregulated rivers directly draining Mount Rainier indicated no statistically significant trends of increasing peak flows over the course of the 20th century. The total sediment load of the upper Nisqually River from 1945 to 2011 was determined to be 1,200,000±180,000 tonnes/yr. The suspended-sediment load in the lower Puyallup River at Puyallup, Washington, was 860,000±300,000 tonnes/yr between 1978 and 1994, but the long-term load for the Puyallup River likely is about 1,000,000±400,000 tonnes/yr. Using a coarse-resolution bedload transport relation, the long-term average bedload was estimated to be about 30,000 tonnes/yr in the lower White River near Auburn, Washington, which was four times greater than bedload in the Puyallup River and an order of magnitude greater than bedload in the Carbon River. Analyses indicate a general increase in the sediment loads in Mount Rainier rivers in the 1990s and 2000s relative to the time period from the 1960s to 1980s. Data are insufficient, however, to determine definitively if post-1990 increases in sediment production and transport from Mount Rainier represent a statistically significant increase relative to sediment-load values typical from Mount Rainier during the entire 20th century. One-dimensional river-hydraulic and sediment-transport models simulated the entrainment, transport, attrition, and deposition of bed material. Simulations showed that bed-material loads were largest for the Nisqually River and smallest for the Carbon River. The models were used to simulate how increases in sediment supply to rivers transport through the river systems and affect lowland reaches. For

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

Science.gov (United States)

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.

Factors influencing storm-generated suspended-sediment concentrations and loads in four basins of contrasting land use, humid-tropical Puerto Rico

Science.gov (United States)

A. C. Gellis; NO-VALUE

2013-01-01

The significant characteristics controlling the variability in storm-generated suspended-sediment loads and concentrations were analyzed for four basins of differing land use (forest, pasture, cropland, and urbanizing) in humid-tropical Puerto Rico. Statistical analysis involved stepwise regression on factor scores. The explanatory variables were attributes of flow,...

Use of antibiotic-loaded cement in total knee arthroplasty.

OpenAIRE

Hinarejos Gómez, Pedro Angel; Guirro Castellnou, Pau; Puig Verdié, Luís; Torres Claramunt, Raúl; Leal Blanquet, Joan; Sánchez Soler, JF.; Monllau García, Juan Carlos

2015-01-01

Bone cement has the capacity to release antibiotic molecules if any antibiotic is included in it, and these elution properties are improved as cement porosity is increased. In vitro studies have shown high local antibiotic concentration for many hours or few days after its use. Antibiotic loaded bone cement (ALBC) is helpful when treating an infection in total knee arthroplasty (TKA) revision surgery. The purpose of this paper was to review the evidence for the routine use of ALBC in TKA in t...

Characterization of sediment transport upstream and downstream from Lake Emory on the Little Tennessee River near Franklin, North Carolina, 2014–15

Science.gov (United States)

Huffman, Brad A.; Hazell, William F.; Oblinger, Carolyn J.

2017-09-06

suspended-sediment load at the downstream site was about 28,300 short tons greater than the upstream site over the study period.As expected, high-flow events (the top 5 percent of daily mean flows) accounted for the majority of the sediment load; 80 percent at the upstream site and 90 percent at the downstream site. A similar relation between turbidity (the top 5 percent of daily mean turbidity) and high loads was also noted. In general, when instantaneous streamflows at the upstream site exceeded 5,000 cubic feet per second, increased daily loads were computed at the downstream site. During low to moderate flows, estimated suspended-sediment loads were lower at the downstream site when compared to the upstream site, which suggests that sediment deposition may be occurring in the intervening reach during those conditions. During the high-flow events, the estimated suspended-sediment loads were higher at the downstream site; however, it is impossible to say with certainty whether the increase in loading was due to scouring of lake sediment, contributions from the additional source area, model error, or a combination of one or more of these factors. The computed loads for a one-week period (December 24–31, 2015), during which the two largest high-flow events of the study period occurred, were approximately 52 percent of the 2015 annual sediment load (36 percent of 2-year load) at the upstream site and approximately 72 percent of the 2015 annual sediment load (57 percent of 2-year load) at the downstream site. Six bedload samples were collected during three events; two high-flow events and one base-flow event. The contribution of bedload to the total sediment load was determined to be insignificant for sampled flows. In general, streamflows for long-term streamgages in the study area were below normal for the majority of the study period; however, flows during the last 3 months of the study period were above normal, including the extreme events during the last week of the

Understanding transport pathways in a river system - Monitoring sediments contaminated by an incident

Science.gov (United States)

Dietrich, S.; Kleisinger, C.; Hillebrand, G.; Claus, E.; Schwartz, R.; Carls, I.; Winterscheid, A.; Schubert, B.

2016-12-01

Experiments to trace transport of sediments and suspended particulate matter on a river scale are an expensive and difficult venture, since it causes a lot of official requirements. In spring 2015, polychlorinated biphenyls (PCB) were released during restoration works at a bridge in the upper part of the Elbe River, near the Czech-German border. In this study, the particle-bound PCB-transport is applied as a tracer for monitoring transport pathways of suspended solids (SS) along a whole river stretch over 700 km length. The incident was monitored by concentration measurements of seven indicator PCB congeners along the inland part of the Elbe River as well as in the Elbe estuary. Data from 15 monitoring stations (settling tanks) as well as from two longitudinal campaigns (grab samples) along the river in July and August 2015 are considered. The total PCB load is calculated for all stations on the basis of monthly contaminant concentrations and daily suspended sediment concentrations. Monte-Carlo simulations assess the uncertainties of the calculated load. 1D water levels and GIS analysis were used to locate temporal storage areas for the SS. It is shown that the ratio of high versus low chlorinated PCB congeners is a suitable tracer to distinguish the PCB load of the incident from the long-term background signal. Furthermore, the reduction of total PCB load within the upper Elbe indicates that roughly 24% of the SS were transported with the water by wash load. Approximately 600 km downstream of the incident site, the PCB-marked wash load was first identified in July 2015. PCB load transported intermittently in suspension was detected roughly 400 km downstream of the incident site by August 2015. In the Elbe Estuary, PCB-marked SS were only found upstream of the steep slope of water depth (approx. 4 to 15 m) within Hamburg harbor that acts as a major sediment sink. Here, SS from the inland Elbe are mixed with lowly contaminated marine material, which may mask the

Sediment deposition and trends and transport of phosphorus and other chemical constituents, Cheney Reservoir watershed, south-central Kansas

Science.gov (United States)

Mau, D.P.

2001-01-01

Sediment deposition, water-quality trends, and mass transport of phosphorus, nitrogen, selected trace elements, and selected pesticides within the Cheney Reservoir watershed in south-central Kansas were investigated using bathymetric survey data and reservoir bottom-sediment cores. Sediment loads in the reservoir were investigated by comparing 1964 topographic data to 1998 bathymetric survey data. Approximately 7,100 acre-feet of sediment deposition occurred in Cheney Reservoir from 1965 through 1998. As of 1998, sediment had filled 27 percent of the reservoir's inactive conservation storage pool, which is less than the design estimate of 34 percent. Mean annual sediment deposition was 209 acre-feet per year, or 0.22 acre-feet per year per square mile, and the mean annual sediment load was 453 million pounds per year. During the 3-year period from 1997 through 1999, 23 sediment cores were collected from the reservoir, and subsamples were analyzed for nutrients (phosphorus and nitrogen species), selected trace elements, and selected organic pesticides. Mean concentrations of total phosphorus in reservoir bottom sediment ranged from 94 milligrams per kilogram at the upstream end of the reservoir to 710 milligrams per kilogram farther downstream near the reservoir dam. The mean concentration for all sites was 480 milligrams per kilogram. Total phosphorus concentrations were greatest when more silt- and clay-sized particles were present. The implications are that if anoxic conditions (inadequate oxygen) occur near the dam, phosphorus could be released from the sediment and affect the drinking-water supply. Analysis of selected cores also indicates that total phosphorus concentrations in the reservoir sediment increased over time and were probably the result of nonpoint-source activities in the watershed, such as increased fertilizer use and livestock production. Mean annual phosphorus loading to Cheney Reservoir was estimated to be 226,000 pounds per year on the basis

Resuspended contaminated sediments cause sublethal stress to oysters: A biomarker differentiates total suspended solids and contaminant effects.

Science.gov (United States)

Edge, Katelyn J; Dafforn, Katherine A; Simpson, Stuart L; Ringwood, Amy H; Johnston, Emma L

2015-06-01

Resuspended contaminated sediments represent an important route of contaminant exposure for aquatic organisms. During resuspension events, filter-feeding organisms are exposed to contaminants, in both the dissolved form (at the gills) and the particulate form (in the digestive system). In addition, these organisms must manage the physical stress associated with an increase in total suspended solids (TSS). To date, few studies have experimentally compared the contributions to biological stress of contaminated and clean suspended solids. The authors mixed field-collected sediments (cellular biomarkers (lysosomal membrane stability, lipid peroxidation, and glutathione) were measured to evaluate sublethal toxicity. Lysosomal membrane stability was the most sensitive biomarker for distinguishing effects from resuspended contaminated sediments, as increasing amounts of contaminated TSS increased lysosomal membrane destabilization. The authors' results illustrate the importance of considering contaminant exposures from resuspended sediments when assessing the toxicity of contaminants to aquatic organisms. © 2015 SETAC.

The relative contribution of near-bed vs. intragravel horizontal transport to fine sediment accumulation processes in river gravel beds

Science.gov (United States)

Casas-Mulet, Roser; Lakhanpal, Garima; Stewardson, Michael J.

2018-02-01

Understanding flow-sediment interactions is important for comprehending river functioning. Fine sediment accumulation processes, in particular, have key implications for ecosystem health. However, the amount of fines generated by intragravel flows and later accumulated in gravel streambeds may have been underestimated, as the hydraulic-related driving transport mechanisms in play are not clearly identified. Specifically, the relative contribution of fines from upper vs. lower sediment layers in gravel beds is not well understood. By recreating flooded and dewatered conditions in an experimental flume filled with natural sediment, we estimated such contributions by observing and collecting intragravel transported fines that were later accumulated into a void in the middle of the sediment matrix. Near-bed transport in the upper sediment layers (named Brinkman load) during flooded conditions accounted for most (90%) of the accumulated fines. Intragravel transport in the lower sediment layers (named Interstitial load) was the sole source of transport and accumulation during dewatered conditions with steeper hydraulic gradients. Interstitial load accounted for 10% of the total transport during flooded conditions. Although small, such estimations demonstrate that hydraulic-gradient transport in the lower sediment layers occurs in spite of the contradicting analytical assessments. We provide a case study to challenge the traditional approaches of assessing intragravel transport, and a useful framework to understand the origin and relative contribution of fine sediment accumulation in gravel beds. Such knowledge will be highly useful for the design of monitoring programs aiding river management, particularly in regulated rivers.

Fine sediment in pools: An index of how sediment is affecting a stream channel

Science.gov (United States)

Tom Lisle; Sue Hilton

1991-01-01

One of the basic issues facing managers of fisheries watersheds is how inputs of sediment affect stream channels. In some cases we can measure and even roughly predict effects of land use on erosion and delivery of sediment from hillslopes to streams. But we are at a loss about how a given increase in sediment load will affect channel morphology, flow conditions, and...

Tropical Cyclones as a Driver of Global Sediment Flux

Science.gov (United States)

Leyland, J.; Darby, S. E.; Cohen, S.

2017-12-01

The world's rivers deliver 19 billion tonnes of sediment to the coastal zone annually. The sediment supplied to the coastal zone is of significant importance for a variety of reasons, for example in acting as a vector for nutrients as well as in supplying sediment to coastal landforms such as deltas and beaches that can buffer those landforms from erosion and flooding. A greater understanding of the factors governing sediment flux to the oceans is therefore a key research gap. The non-linear relationship between river discharge and sediment flux implies that the global sediment flux may be disproportionately driven by large floods. Indeed, in our recent empirical research we have demonstrated that changes in the track locations, frequency and intensity of tropical storms in recent decades exert a significant control on the sediment flux emanating from the Mekong River. Since other large rivers potentially affected by tropical storms are known to make a significant contribution to the global sediment flux, this raises the question of the extent to which such storms play a significant role in controlling sediment loads at the global scale. In this paper we address that question by employing a global hydrological model (WBMsed) in order to predict runoff and sediment load forced by recent historical climate scenarios `with' and `without' tropical cyclones. We compare the two scenarios to (i) make the first estimate of the global contribution of sediment load forced by tropical storms; (ii) evaluate how that contribution has varied in recent decades and to (iii) explore variations in tropical-storm driven sediment loads in selected major river basins that are significantly affected by such storms.

Multiple time scale analysis of sediment and runoff changes in the Lower Yellow River

Directory of Open Access Journals (Sweden)

K. Chi

2018-06-01

Full Text Available Sediment and runoff changes of seven hydrological stations along the Lower Yellow River (LYR (Huayuankou Station, Jiahetan Station, Gaocun Station, Sunkou Station, Ai Shan Station, Qikou Station and Lijin Station from 1980 to 2003 were alanyzed at multiple time scale. The maximum value of monthly, daily and hourly sediment load and runoff conservations were also analyzed with the annually mean value. Mann–Kendall non-parametric mathematics correlation test and Hurst coefficient method were adopted in the study. Research results indicate that (1 the runoff of seven hydrological stations was significantly reduced in the study period at different time scales. However, the trends of sediment load in these stations were not obvious. The sediment load of Huayuankou, Jiahetan and Aishan stations even slightly increased with the runoff decrease. (2 The trends of the sediment load with different time scale showed differences at Luokou and Lijin stations. Although the annually and monthly sediment load were broadly flat, the maximum hourly sediment load showed decrease trend. (3 According to the Hurst coefficients, the trend of sediment and runoff will be continue without taking measures, which proved the necessary of runoff-sediment regulation scheme.

Waste Load Allocation Based on Total Maximum Daily Load Approach Using the Charged System Search (CSS Algorithm

Directory of Open Access Journals (Sweden)

Elham Faraji

2016-03-01

Full Text Available In this research, the capability of a charged system search algorithm (CSS in handling water management optimization problems is investigated. First, two complex mathematical problems are solved by CSS and the results are compared with those obtained from other metaheuristic algorithms. In the last step, the optimization model developed by the CSS algorithm is applied to the waste load allocation in rivers based on the total maximum daily load (TMDL concept. The results are presented in Tables and Figures for easy comparison. The study indicates the superiority of the CSS algorithm in terms of its speed and performance over the other metaheuristic algorithms while its precision in water management optimization problems is verified.

Evaluation of Sediment Trap Efficiency in an Estuarine Environment

National Research Council Canada - National Science Library

Stoddard, Daniel

2001-01-01

.... A second trap of same dimensions was also incorporated 420 m upstream. Trap efficiency was calculated as a sediment removal ratio, or the percentage by which influent sediment load to the trap is reduced in the effluent load from the trap...

Magnetic susceptibility as a simple tracer for fluvial sediment source ascription during storm events.

Science.gov (United States)

Rowntree, Kate M; van der Waal, Bennie W; Pulley, Simon

2017-06-01

Sediment tracing using a single tracer, low frequency magnetic susceptibility (X lf ), was used to apportion suspended sediment to geologically defined source areas and to interpret sediment source changes during flood events in the degraded catchment of the Vuvu River, a headwater tributary of the Mzimbubu River, South Africa. The method was tested as a simple tool for use by catchment managers concerned with controlling erosion. The geology of the 58 km 2 catchment comprises two distinct formations: basalt in the upper catchment with a characteristically high magnetic susceptibility and shales with a low magnetic susceptibility in the lower catchment. Application of an unmixing model incorporating a Monte Carlo uncertainty analysis showed that X lf provided a means to assign the proportion of each geological province contributing to the river's sediment load. Grab water samples were collected at ten-minute intervals during flood events for subsequent analysis of suspended sediment concentration and the magnetic susceptibility of the filtered sediment. Two floods are presented in detail, the first represents a significant event at the start of the wet season (max. discharge 32 m 3  s -1 ); the second was a smaller flood (max discharge 14 m 3  s -1 ) that occurred a month later. Suspended sediment concentrations during the twelve monitored events showed a characteristic decline over the wet season. The main source of suspended sediment was shown to be from the mudstones in the lower catchment, which contributed 86% of the total measured load. The sediment dynamics during the two floods monitored in detail were quite different from each other. In the first the sediment concentration was high (11 g L -1 ), peaking after the flood peak. The X lf value increased during the event, indicating that contribution to the sediment load from basalt in the upper catchment increased during the recession limb. In the second, smaller flood the sediment peak (6 g L -1

Sediment acoustic index method for computing continuous suspended-sediment concentrations

Science.gov (United States)

Landers, Mark N.; Straub, Timothy D.; Wood, Molly S.; Domanski, Marian M.

2016-07-11

Suspended-sediment characteristics can be computed using acoustic indices derived from acoustic Doppler velocity meter (ADVM) backscatter data. The sediment acoustic index method applied in these types of studies can be used to more accurately and cost-effectively provide time-series estimates of suspended-sediment concentration and load, which is essential for informed solutions to many sediment-related environmental, engineering, and agricultural concerns. Advantages of this approach over other sediment surrogate methods include: (1) better representation of cross-sectional conditions from large measurement volumes, compared to other surrogate instruments that measure data at a single point; (2) high temporal resolution of collected data; (3) data integrity when biofouling is present; and (4) less rating curve hysteresis compared to streamflow as a surrogate. An additional advantage of this technique is the potential expansion of monitoring suspended-sediment concentrations at sites with existing ADVMs used in streamflow velocity monitoring. This report provides much-needed standard techniques for sediment acoustic index methods to help ensure accurate and comparable documented results.

Grazing management effects on sediment, phosphorus, and pathogen loading of streams in cool-season grass pastures.

Science.gov (United States)

Schwarte, Kirk A; Russell, James R; Kovar, John L; Morrical, Daniel G; Ensley, Steven M; Yoon, Kyoung-Jin; Cornick, Nancy A; Cho, Yong Il

2011-01-01

Erosion and runoff from pastures may lead to degradation of surface water. A 2-yr grazing study was conducted to quantify the effects of grazing management on sediment, phosphorus (P), and pathogen loading of streams in cool-season grass pastures. Six adjoining 12.1-ha pastures bisected by a stream in central Iowa were divided into three treatments: continuous stocking with unrestricted stream access (CSU), continuous stocking with restricted stream access (CSR), and rotational stocking (RS). Rainfall simulations on stream banks resulted in greater ( CSR pastures. Bovine enterovirus was shed by an average of 24.3% of cows during the study period and was collected in the runoff of 8.3 and 16.7% of runoff simulations on bare sites in CSU pastures in June and October of 2008, respectively, and from 8.3% of runoff simulations on vegetated sites in CSU pastures in April 2009. Fecal pathogens (bovine coronavirus [BCV], bovine rotavirus group A, and O157:H7) shed or detected in runoff were almost nonexistent; only BCV was detected in feces of one cow in August of 2008. Erosion of cut-banks was the greatest contributor of sediment and P loading to the stream; contributions from surface runoff and grazing animals were considerably less and were minimized by grazing management practices that reduced congregation of cattle by pasture streams. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Estimating concentrations of fine-grained and total suspended sediment from close-range remote sensing imagery

Science.gov (United States)

Mosbrucker, Adam; Spicer, Kurt R.; Christianson, Tami; Uhrich, Mark A.

2015-01-01

data range among sensors. Of greatest interest to many programs is a hysteresis in the relationship between turbidity and SSC, attributed to temporal variation of particle size distribution (Landers and Sturm, 2013; Uhrich et al., 2014). This phenomenon causes increased uncertainty in regression-estimated values of SSC, due to changes in nephelometric reflectance off the varying grain sizes in suspension (Uhrich et al., 2014). Here, we assess the feasibility and application of close-range remote sensing to quantify SSC and particle size distribution of a disturbed, and highly-turbid, river system. We use a consumer-grade digital camera to acquire imagery of the river surface and a depth-integrating sampler to collect concurrent suspended-sediment samples. We then develop two empirical linear regression models to relate image spectral information to concentrations of fine sediment (clay to silt) and total suspended sediment. Before presenting our regression model development, we briefly summarize each data-acquisition method.

Tracing cohesive sediment transportation at river mouths around Tokyo, Japan by Cesium originated from Fukushima Daiichi Power Plant

Science.gov (United States)

koibuchi, Y.

2012-12-01

Sediment transport at river mouths, which consists of suspended-load and bed-load, has not been fully understood, since bed-load transport of cohesive sand is difficult to observe. Especially, the impact of sediment transport on the total amount of fine-grained cohesive sediment has not been elucidated. Cesium-134 and cesium-137 were spread from the Fukushima Daiichi Nuclear Power Plant (FDNPP) after the earthquake of March 11 of 2011, and attached to the fine-grained sand on the land. The contaminated sand flowed into the river mouths through the rivers possibly due to the complex physical processes in estuarine areas. To evaluate the fine-grained sediment transport around Tokyo and Tokyo Bay, field observations were carried out utilizing radionuclide originated from FDNPP as an effective tracer. The cohesive sediment transport at three different river mouths around Tokyo was successfully quantified. The cohesive sediment transport deposited in the estuary was found to be greatly dependent on the land use, geometry, river discharge and salinity. In addition,the transport driven by the rainfall was minute, and its behavior was quite different from suspended solids. Although further field observations of radionuclide are necessary, it is clear that fine-grained sediment in the bay from rivers already settled on the river mouth by aggregation. The settled sand will not move even in rainfall events. Consequently, the transport of radionuclide to the Pacific Ocean may not occur.; Cesium distribution around Tokyo Bay ; Cesium Concentration in Edogawa river

An exploratory study of using external fluid loading on a vibrating tube for measuring suspended sediment concentration in water

International Nuclear Information System (INIS)

Hsu, Y-S; Hwang, Y-F; Huang, J H

2008-01-01

This paper presents an exploratory study of using external fluid loading on a vibrating tube for measuring the suspended sediment concentration (SSC) in bodies of water such as rivers and reservoirs. This new measuring concept provides an opportunity for an automated on-site monitoring of the conditions in a body of water by taking the fluid sample instantaneously in the area surrounding the vibrating tube. The physical properties of the fluid sample are those of the fluid that naturally flows around the tube, and are more representative of those of the water with SSC to be measured. The theoretical analysis presented in this paper shows that the resonance frequencies of an immersed vibrating tube change significantly with mass density variations that normally occur in bodies of water with suspended sediment. These changes are sensitive enough to have a possible 1% resolution of the measured fluid density. The signal processing issues are discussed, and a schematic of a conceptual measuring setup is proposed. Based on the theoretical analyses and other measurement issues presented in the paper, using the loading by external fluid on a vibrating tube is feasible for measuring the SSC in water bodies

Continental Shelf Sediments of Sarawak, Malaysian Borneo

Science.gov (United States)

Masron, Tarmiji; Rumpet, Richard; Musel, Jamil

2017-01-01

Sediment distributions in deep sea influence the benthic community structure and thus play an important role in shaping the marine ecosystem. Several studies on sediment characteristics had been conducted in South China Sea (SCS), but only limited to coastal areas of regions within SCS territories. Therefore, this study was carried out to analyze the benthic sediment profile in an area beyond 12 nautical miles off the coast of Sarawak, southern SCS. Sediment samples were collected from 31 stations, comprising three depth ranges: (I) 20–50 m, (II) 50–100 m, and (III) 100–200 m. The total organic matter (TOM) contents were determined and subjected to dry and wet sieving methods for particle size analysis. TOM contents in the deep area (>50 m) were significantly higher (p = 0.05) and positively correlated (r = 0.73) with silt-clay fraction. About 55% and 82% of stations in strata II and III, respectively, were dominated by silt-clay fractions (50 m) tend to be poorly sorted, very fine skewed, and platykurtic. Unlike data obtained 20 years ago which reported high content of silt-clay (58%), this study recorded a lower content (35%); therefore, changes in sediment load had been observed in southern SCS. PMID:29075660

Sediment supply to beaches

DEFF Research Database (Denmark)

Aagaard, Troels

2014-01-01

Many beaches have been built by an onshore supply of sand from the shoreface, and future long-term coastal evolution critically depends on cross-shore sediment exchange between the upper and the lower shorefaces. Even so, cross-shore sediment supply remains poorly known in quantitative terms...... and this reduces confidence in predictions of long-term shoreline change. In this paper, field measurements of suspended sediment load and cross-shore transport on the lower shoreface are used to derive a model for sediment supply from the lower to the upper shoreface at large spatial and temporal scales. Data...

Fluvial sediment supply to a mega-delta reduced by shifting tropical-cyclone activity.

Science.gov (United States)

Darby, Stephen E; Hackney, Christopher R; Leyland, Julian; Kummu, Matti; Lauri, Hannu; Parsons, Daniel R; Best, James L; Nicholas, Andrew P; Aalto, Rolf

2016-11-10

The world's rivers deliver 19 billion tonnes of sediment to the coastal zone annually, with a considerable fraction being sequestered in large deltas, home to over 500 million people. Most (more than 70 per cent) large deltas are under threat from a combination of rising sea levels, ground surface subsidence and anthropogenic sediment trapping, and a sustainable supply of fluvial sediment is therefore critical to prevent deltas being 'drowned' by rising relative sea levels. Here we combine suspended sediment load data from the Mekong River with hydrological model simulations to isolate the role of tropical cyclones in transmitting suspended sediment to one of the world's great deltas. We demonstrate that spatial variations in the Mekong's suspended sediment load are correlated (r = 0.765, P sediment load reaching the delta is delivered by runoff generated by rainfall associated with tropical cyclones. Furthermore, we estimate that the suspended load to the delta has declined by 52.6 ± 10.2 megatonnes over recent years (1981-2005), of which 33.0 ± 7.1 megatonnes is due to a shift in tropical-cyclone climatology. Consequently, tropical cyclones have a key role in controlling the magnitude of, and variability in, transmission of suspended sediment to the coast. It is likely that anthropogenic sediment trapping in upstream reservoirs is a dominant factor in explaining past, and anticipating future, declines in suspended sediment loads reaching the world's major deltas. However, our study shows that changes in tropical-cyclone climatology affect trends in fluvial suspended sediment loads and thus are also key to fully assessing the risk posed to vulnerable coastal systems.

Measuring hypoxia induced metal release from highly contaminated estuarine sediments during a 40 day laboratory incubation experiment

Energy Technology Data Exchange (ETDEWEB)

Banks, Joanne L., E-mail: jlbanks@student.unimelb.edu.au [Department of Zoology, University of Melbourne, Victoria, 3010 Australia (Australia); Ross, D. Jeff, E-mail: Jeff.Ross@utas.edu.au [Institute of Marine and Antarctic Studies, Nubeena Crescent, Taroona, Tasmania, 7053 Australia (Australia); Keough, Michael J., E-mail: mjkeough@unimelb.edu.au [Department of Zoology, University of Melbourne, Victoria, 3010 Australia (Australia); Eyre, Bradley D., E-mail: bradley.eyre@scu.edu.au [Centre for Coastal Biogeochemistry, School of Environmental Science and Management, Southern Cross University, PO Box 157, Lismore, NSW, 2480 Australia (Australia); Macleod, Catriona K., E-mail: Catriona.Macleod@utas.edu.au [Institute of Marine and Antarctic Studies, Nubeena Crescent, Taroona, Tasmania, 7053 Australia (Australia)

2012-03-15

Nutrient inputs to estuarine and coastal waters worldwide are increasing and this in turn is increasing the prevalence of eutrophication and hypoxic and anoxic episodes in these systems. Many urbanised estuaries are also subject to high levels of anthropogenic metal contamination. Environmental O{sub 2} levels may influence whether sediments act as sinks or sources of metals. In this study we investigated the effect of an extended O{sub 2} depletion event (40 days) on fluxes of trace metals (and the metalloid As) across the sediment-water interface in sediments from a highly metal contaminated estuary in S.E. Tasmania, Australia. We collected sediments from three sites that spanned a range of contamination and measured total metal concentration in the overlying water using sealed core incubations. Manganese and iron, which are known to regulate the release of other divalent cations from sub-oxic sediments, were released from sediments at all sites as hypoxia developed. In contrast, the release of arsenic, cadmium, copper and zinc was comparatively low, most likely due to inherent stability of these elements within the sediments, perhaps as a result of their refractory origin, their association with fine-grained sediments or their being bound in stable sulphide complexes. Metal release was not sustained due to the powerful effect of metal-sulphide precipitation of dissolved metals back into sediments. The limited mobilisation of sediment bound metals during hypoxia is encouraging, nevertheless the results highlight particular problems for management in areas where hypoxia might occur, such as the release of metals exacerbating already high loads or resulting in localised toxicity. - Highlights: Black-Right-Pointing-Pointer Metal contaminated sediments exposed to long-term hypoxia released Mn and Fe pulses. Black-Right-Pointing-Pointer As flux increased under anoxic conditions Cd, Cu and Zn fluxes occurred only during the first week of hypoxia. Black

Transport and deposition of asbestos-rich sediment in the Sumas River, Whatcom County, Washington

Science.gov (United States)

Curran, Christopher A.; Anderson, Scott W.; Barbash, Jack E.; Magirl, Christopher S.; Cox, Stephen E.; Norton, Katherine K.; Gendaszek, Andrew S.; Spanjer, Andrew R.; Foreman, James R.

2016-02-08

Heavy sediment loads in the Sumas River of Whatcom County, Washington, increase seasonal turbidity and cause locally acute sedimentation. Most sediment in the Sumas River is derived from a deep-seated landslide of serpentinite that is located on Sumas Mountain and drained by Swift Creek, a tributary to the Sumas River. This mafic sediment contains high amounts of naturally occurring asbestiform chrysotile. A known human-health hazard, asbestiform chrysotile comprises 0.25–37 percent, by mass, of the total suspended sediment sampled from the Sumas River as part of this study, which included part of water year 2011 and all of water years 2012 and 2013. The suspended-sediment load in the Sumas River at South Pass Road, 0.6 kilometers (km) downstream of the confluence with Swift Creek, was 22,000 tonnes (t) in water year 2012 and 49,000 t in water year 2013. The suspended‑sediment load at Telegraph Road, 18.8 km downstream of the Swift Creek confluence, was 22,000 t in water year 2012 and 27,000 t in water year 2013. Although hydrologic conditions during the study were wetter than normal overall, the 2-year flood peak was only modestly exceeded in water years 2011 and 2013; runoff‑driven geomorphic disturbance to the watershed, which might have involved mass wasting from the landslide, seemed unexceptional. In water year 2012, flood peaks were modest, and the annual streamflow was normal. The fact that suspended-sediment loads in water year 2012 were equivalent at sites 0.6 and 18.8 km downstream of the sediment source indicates that the conservation of suspended‑sediment load can occur under normal hydrologic conditions. The substantial decrease in suspended-sediment load in the downstream direction in water year 2013 was attributed to either sedimentation in the intervening river reach, transfer to bedload as an alternate mode of sediment transport, or both.The sediment in the Sumas River is distinct from sediment in most other river systems because of the

Total Antioxidant Capacity and Total Oxidant Status in Saliva of Periodontitis Patients in Relation to Bacterial Load

Science.gov (United States)

Zhang, Taowen; Andrukhov, Oleh; Haririan, Hady; Müller-Kern, Michael; Liu, Shutai; Liu, Zhonghao; Rausch-Fan, Xiaohui

2016-01-01

The detection of salivary biomarkers has a potential application in early diagnosis and monitoring of periodontal inflammation. However, searching sensitive salivary biomarkers for periodontitis is still ongoing. Oxidative stress is supposed to play an important role in periodontitis progression and tissue destruction. In this cross-sectional study, we investigated total antioxidant capacity (TAC) and total oxidant status (TOS) in saliva of periodontitis patients compared to healthy controls and their relationship with periodontopathic bacteria and periodontal disease severity. Unstimulated saliva was collected from 45 patients with generalized severe periodontitis and 37 healthy individuals and the TAC/TOS were measured. In addition, salivary levels of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Fusobacterium nucleatum in saliva were measured. Salivary TAC was lower in periodontitis patients compared to healthy controls. Moreover, a significant negative correlation of salivary TAC with clinical attachment loss was observed in periodontitis patients. No significant difference in the salivary TOS was observed between periodontitis patients and healthy controls. Bacterial load was enhanced in periodontitis patients and exhibited correlation with periodontal disease severity but not with salivary TAC/TOS. Our data suggest that changes in antioxidant capacity in periodontitis patients are not associated with increased bacterial load and are probably due to a dysregulated immune response. PMID:26779448

Total antioxidant capacity and total oxidant status in saliva of periodontitis patients in relation to bacterial load

Directory of Open Access Journals (Sweden)

Taowen eZhang

2016-01-01

Full Text Available The detection of salivary biomarkers has a potential application in early diagnosis and monitoring of periodontal inflammation. However, searching sensitive salivary biomarkers for periodontitis is still ongoing. Oxidative stress is supposed to play an important role in periodontitis progression and tissue destruction. In this cross-sectional study, we investigated total antioxidant capacity (TAC and total oxidant status (TOS in saliva of periodontitis patients compared to healthy controls and their relationship with periodontopathic bacteria and periodontal disease severity. Unstimulated saliva was collected from 45 patients with generalized severe periodontitis and 37 healthy individuals and the TAC/TOS were measured. In addition, salivary levels of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Fusobacterium nucleatum in saliva were measured. Salivary TAC was lower in periodontitis patients compared to healthy controls. Moreover, a significant negative correlation of salivary TAC with clinical attachment loss was observed in periodontitis patients. No significant difference in the salivary TOS was observed between periodontitis patients and healthy controls. Bacterial load was enhanced in periodontitis patients and exhibited correlation with periodontal disease severity but not with salivary TAC/TOS. Our data suggest that changes in antioxidant capacity in periodontitis patients are not associated with increased bacterial load and are probably due to a dysregulated immune response.

Comparison of Toxicity of Sediments from Rivers with Different Levels of Anthropogenic Load (Middle Volga Region, Russia Based on Elutriate and Whole Sediment Tests

Directory of Open Access Journals (Sweden)

N.Yu. Stepanova

2016-09-01

Full Text Available Description of chemical characteristics and toxicity testing of whole sediment and elutri-ate have been performed with 35 samples taken during the monitoring of rivers in the Middle Volga region (Tatarstan, Russia in 2013. The locations analyzed are sites associated with agriculture, forestry, and petroleum hydrocarbons (oil production. The toxicity tests include: (1 Chlorella vulgaris (algal elutriate test, (2 Paramecium caudatum (ciliate elutriate test, (3 Daphnia magna (cladoceran whole sediment toxicity test, and (4 Heterocypris incongruens (ostracod whole sediment toxicity test. The concentrations of metals in 43% of sediment samples have been found to exceed probable effect concentration sediment quality guidelines (SQGs. However, the concentrations of polycyclic aromatic hydrocarbons (PAHs and organochlorine pesticides have turned out to be below SQGs in most sites. The correlation analysis has shown metal toxicity to daphnid reproduction and ostracod growth (R2 = 0.34–0.64 and ammonia (R2 = 0.49–0.54. A higher percentage of samples have shown toxicity in the whole sediment tests (86% compared to the elutriate tests (54%. A total of 91% of samples have demonstrated toxicity for at least one species. Toxicity has been most frequently observed for daphnid reproduction (83% of samples and ostracod growth (56% of samples compared to daphnid (23% survival, ostracod (11% survival, and ciliate reproduction (54% or algal growth (54%. The most polluted sediments have been registered in the area of oil production. The comparison of toxicity of the samples from different types of areas has indicated that 100% of samples from the oil production area, 94% of samples from the agricultural area, and 50% of samples from the forest area were toxic to at least one test organism.

Distinguishing the impacts of human activities and climate variability on runoff and sediment load change based on paired periods with similar weather conditions

NARCIS (Netherlands)

Wang, Fei; Hessel, Rudi; Mu, Xingmin; Maroulis, Jerry; Zhao, Guangju; Geissen, Violette; Ritsema, Coen

2015-01-01

Runoff and sediment loads from river basin are largely affected by the interplay of climate variability and human activities within the basin. However, distinguishing the impacts of climate variability and human activities would vastly improve our knowledge of water resources, climate variability

Seasonal and spatial distributions of tributyltin in surface sediment of the Tolka Estuary, Dublin, Ireland

Energy Technology Data Exchange (ETDEWEB)

Buggy, Conor J. [Department of Biotechnology, Dublin City University, Glasnevin, Dublin (Ireland); Tobin, John M. [Department of Biotechnology, Dublin City University, Glasnevin, Dublin (Ireland)]. E-mail: john.tobin@dcu.ie

2006-09-15

Aquatic pollution by tributyltin (TBT) is of concern because of its high toxicity to marine life. TBT loadings of estuarine sediments may remain elevated because of long flushing times in estuaries due to their enclosed physicality. The Tolka Estuary, Co. Dublin, Ireland, is a typical Irish urban estuary. It has a significant pollution loading. The results of 12 months' analysis of TBT spatial and temporal distributions in this estuary are presented in this paper. Data from a total of 10 sample points are presented. The concentrations of TBT in the sediment were analysed using differential pulse polarography. Significant seasonal and spatial trends in TBT distribution were observed over the 12-month period. TBT concentrations ranged from 0.1 ppb in winter to 8.6 ppb in summer with a 1.5 ppb average. Organic matter (OM) concentrations of sediment exhibited similar seasonal trends and a positive correlation between OM and TBT distributions was observed. - TBT concentrations varied with seasons and correlated well with organic matter.

Seasonal and spatial distributions of tributyltin in surface sediment of the Tolka Estuary, Dublin, Ireland

International Nuclear Information System (INIS)

Buggy, Conor J.; Tobin, John M.

2006-01-01

Aquatic pollution by tributyltin (TBT) is of concern because of its high toxicity to marine life. TBT loadings of estuarine sediments may remain elevated because of long flushing times in estuaries due to their enclosed physicality. The Tolka Estuary, Co. Dublin, Ireland, is a typical Irish urban estuary. It has a significant pollution loading. The results of 12 months' analysis of TBT spatial and temporal distributions in this estuary are presented in this paper. Data from a total of 10 sample points are presented. The concentrations of TBT in the sediment were analysed using differential pulse polarography. Significant seasonal and spatial trends in TBT distribution were observed over the 12-month period. TBT concentrations ranged from 0.1 ppb in winter to 8.6 ppb in summer with a 1.5 ppb average. Organic matter (OM) concentrations of sediment exhibited similar seasonal trends and a positive correlation between OM and TBT distributions was observed. - TBT concentrations varied with seasons and correlated well with organic matter

A simple approach to estimate daily loads of total, refractory, and labile organic carbon from their seasonal loads in a watershed.

Science.gov (United States)

Ouyang, Ying; Grace, Johnny M; Zipperer, Wayne C; Hatten, Jeff; Dewey, Janet

2018-05-22

Loads of naturally occurring total organic carbons (TOC), refractory organic carbon (ROC), and labile organic carbon (LOC) in streams control the availability of nutrients and the solubility and toxicity of contaminants and affect biological activities through absorption of light and complex metals with production of carcinogenic compounds. Although computer models have become increasingly popular in understanding and management of TOC, ROC, and LOC loads in streams, the usefulness of these models hinges on the availability of daily data for model calibration and validation. Unfortunately, these daily data are usually insufficient and/or unavailable for most watersheds due to a variety of reasons, such as budget and time constraints. A simple approach was developed here to calculate daily loads of TOC, ROC, and LOC in streams based on their seasonal loads. We concluded that the predictions from our approach adequately match field measurements based on statistical comparisons between model calculations and field measurements. Our approach demonstrates that an increase in stream discharge results in increased stream TOC, ROC, and LOC concentrations and loads, although high peak discharge did not necessarily result in high peaks of TOC, ROC, and LOC concentrations and loads. The approach developed herein is a useful tool to convert seasonal loads of TOC, ROC, and LOC into daily loads in the absence of measured daily load data.

Mercury in sediment, water, and fish in a managed tropical wetland-lake ecosystem.

Science.gov (United States)

Malczyk, Evan A; Branfireun, Brian A

2015-08-15

Mercury pollution has not been well documented in the inland lakes or fishes of Mexico, despite the importance of freshwater fish as a source of protein in local diets. Total mercury and methylmercury in waters, sediments, and the commercial fish catch were investigated in Lake Zapotlán, Mexico. Concentrations of total and methylmercury were very high in runoff and wastewater inputs, but very low in sediments and surface waters of the open water area of the lake. Concentrations of total mercury in tilapia and carp were very low, consistent with the low concentrations in lake water and sediments. Particle settling, sorption, the biogeochemical environment, and/or bloom dilution are all plausible explanations for the significant reductions in both total mercury and methylmercury. Despite very high loading of mercury, this shallow tropical lake was not a mercury-impaired ecosystem, and these findings may translate across other shallow, alkaline tropical lakes. Importantly, the ecosystem services that seemed to be provided by peripheral wetlands in reducing mercury inputs highlight the potential for wetland conservation or restoration in Mexico. Copyright © 2015. Published by Elsevier B.V.

Impacts of Rainfall and Land Use on Sediment Regime in a Semi-Arid Region: Case Study of the Wuqi Catchment in the Upper Beiluo River Basin, China

NARCIS (Netherlands)

Zhu, J.; Gao, P.; Geissen, V.; Maroulis, J.; Ritsema, C.J.; Mu, X.; Zhao, G.

2015-01-01

The middle reaches of the Yellow River Basin transport the vast majority of sediment (>85% of the basin's total available sediment load), which has had profound effects on the characteristics of the middle and lower reaches of the Yellow River. With recent land use and land cover change, the

Concentrations and loads of suspended sediment-associated pesticides in the San Joaquin River, California and tributaries during storm events

Science.gov (United States)

Hladik, M.L.; Domagalski, Joseph L.; Kuivila, K.M.

2009-01-01

Current-use pesticides associated with suspended sediments were measured in the San Joaquin River, California and its tributaries during two storm events in 2008. Nineteen pesticides were detected: eight herbicides, nine insecticides, one fungicide and one insecticide synergist. Concentrations for the herbicides (0.1 to 3000 ng/g; median of 6.1 ng/g) were generally greater than those for the insecticides (0.2 to 51 ng/g; median of 1.5 ng/g). Concentrations in the tributaries were usually greater than in the mainstem San Joaquin River and the west side tributaries were higher than the east side tributaries. Estimated instantaneous loads ranged from 1.3 to 320 g/day for herbicides and 0.03 to 53 g/day for insecticides. The greatest instantaneous loads came from the Merced River on the east side. Instantaneous loads were greater for the first storm of 2008 than the second storm in the tributaries while the instantaneous loads within the San Joaquin River were greater during the second storm. Pesticide detections generally reflected pesticide application, but other factors such as physical-chemical properties and timing of application were also important to pesticide loads.

Using remotely sensed imagery to estimate potential annual pollutant loads in river basins.

Science.gov (United States)

He, Bin; Oki, Kazuo; Wang, Yi; Oki, Taikan

2009-01-01

Land cover changes around river basins have caused serious environmental degradation in global surface water areas, in which the direct monitoring and numerical modeling is inherently difficult. Prediction of pollutant loads is therefore crucial to river environmental management under the impact of climate change and intensified human activities. This research analyzed the relationship between land cover types estimated from NOAA Advanced Very High Resolution Radiometer (AVHRR) imagery and the potential annual pollutant loads of river basins in Japan. Then an empirical approach, which estimates annual pollutant loads directly from satellite imagery and hydrological data, was investigated. Six water quality indicators were examined, including total nitrogen (TN), total phosphorus (TP), suspended sediment (SS), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Dissolved Oxygen (DO). The pollutant loads of TN, TP, SS, BOD, COD, and DO were then estimated for 30 river basins in Japan. Results show that the proposed simulation technique can be used to predict the pollutant loads of river basins in Japan. These results may be useful in establishing total maximum annual pollutant loads and developing best management strategies for surface water pollution at river basin scale.

Increased terrestrial to ocean sediment and carbon fluxes in the northern Chesapeake Bay associated with twentieth century land alteration

Science.gov (United States)

Saenger, C.; Cronin, T. M.; Willard, D.; Halka, J.; Kerhin, R.

2008-01-01

We calculated Chesapeake Bay (CB) sediment and carbon fluxes before and after major anthropogenic land clearance using robust monitoring, modeling and sedimentary data. Four distinct fluxes in the estuarine system were considered including (1) the flux of eroded material from the watershed to streams, (2) the flux of suspended sediment at river fall lines, (3) the burial flux in tributary sediments, and (4) the burial flux in main CB sediments. The sedimentary maximum in Ambrosia (ragweed) pollen marked peak land clearance (~1900 a.d.). Rivers feeding CB had a total organic carbon (TOC)/total suspended solids of 0.24??0.12, and we used this observation to calculate TOC fluxes from sediment fluxes. Sediment and carbon fluxes increased by 138-269% across all four regions after land clearance. Our results demonstrate that sediment delivery to CB is subject to significant lags and that excess post-land clearance sediment loads have not reached the ocean. Post-land clearance increases in erosional flux from watersheds, and burial in estuaries are important processes that must be considered to calculate accurate global sediment and carbon budgets. ?? 2008 Coastal and Estuarine Research Federation.

Measuring hypoxia induced metal release from highly contaminated estuarine sediments during a 40 day laboratory incubation experiment

International Nuclear Information System (INIS)

Banks, Joanne L.; Ross, D. Jeff; Keough, Michael J.; Eyre, Bradley D.; Macleod, Catriona K.

2012-01-01

Nutrient inputs to estuarine and coastal waters worldwide are increasing and this in turn is increasing the prevalence of eutrophication and hypoxic and anoxic episodes in these systems. Many urbanised estuaries are also subject to high levels of anthropogenic metal contamination. Environmental O 2 levels may influence whether sediments act as sinks or sources of metals. In this study we investigated the effect of an extended O 2 depletion event (40 days) on fluxes of trace metals (and the metalloid As) across the sediment–water interface in sediments from a highly metal contaminated estuary in S.E. Tasmania, Australia. We collected sediments from three sites that spanned a range of contamination and measured total metal concentration in the overlying water using sealed core incubations. Manganese and iron, which are known to regulate the release of other divalent cations from sub-oxic sediments, were released from sediments at all sites as hypoxia developed. In contrast, the release of arsenic, cadmium, copper and zinc was comparatively low, most likely due to inherent stability of these elements within the sediments, perhaps as a result of their refractory origin, their association with fine-grained sediments or their being bound in stable sulphide complexes. Metal release was not sustained due to the powerful effect of metal-sulphide precipitation of dissolved metals back into sediments. The limited mobilisation of sediment bound metals during hypoxia is encouraging, nevertheless the results highlight particular problems for management in areas where hypoxia might occur, such as the release of metals exacerbating already high loads or resulting in localised toxicity. - Highlights: ► Metal contaminated sediments exposed to long-term hypoxia released Mn and Fe pulses. ► As flux increased under anoxic conditions Cd, Cu and Zn fluxes occurred only during the first week of hypoxia. ► Flux of these metals from 3 sites was not related to total sediment metal

Using spatially detailed water-quality data and solute-transport modeling to improve support total maximum daily load development

Science.gov (United States)

Walton-Day, Katherine; Runkel, Robert L.; Kimball, Briant A.

2012-01-01

Spatially detailed mass-loading studies and solute-transport modeling using OTIS (One-dimensional Transport with Inflow and Storage) demonstrate how natural attenuation and loading from distinct and diffuse sources control stream water quality and affect load reductions predicted in total maximum daily loads (TMDLs). Mass-loading data collected during low-flow from Cement Creek (a low-pH, metal-rich stream because of natural and mining sources, and subject to TMDL requirements) were used to calibrate OTIS and showed spatially variable effects of natural attenuation (instream reactions) and loading from diffuse (groundwater) and distinct sources. OTIS simulations of the possible effects of TMDL-recommended remediation of mine sites showed less improvement to dissolved zinc load and concentration (14% decrease) than did the TMDL (53-63% decrease). The TMDL (1) assumed conservative transport, (2) accounted for loads removed by remediation by subtracting them from total load at the stream mouth, and (3) did not include diffuse-source loads. In OTIS, loads were reduced near their source; the resulting concentration was decreased by natural attenuation and increased by diffuse-source loads during downstream transport. Thus, by not including natural attenuation and loading from diffuse sources, the TMDL overestimated remediation effects at low flow. Use of the techniques presented herein could improve TMDLs by incorporating these processes during TMDL development.

Field experimental observations of highly graded sediment plumes

DEFF Research Database (Denmark)

Hjelmager Jensen, Jacob; Saremi, Sina; Jimenez, Carlos

2015-01-01

A field experiment in the waters off the south-eastern coast of Cyprus was carried out to study near-field formation of sediment plumes from dumping. Different loads of sediment were poured into calm and limpid waters one at the time from just above the sea surface. The associated plumes......-bed positions gives unique insight into the dynamics of the descending plume and near-field dispersion processes, and enables good understanding of flow and sediment transport processes involved from-release-to-deposition of the load in a non-scaled environment. The high resolution images and footages...... are available through the link provided herein. Observations support the development of a detailed multi-fractional sediment plume model....

Biological treatment of PAH-contaminated sediments in a Sequencing Batch Reactor

International Nuclear Information System (INIS)

Chiavola, Agostina; Baciocchi, Renato; Gavasci, Renato

2010-01-01

The technical feasibility of a sequential batch process for the biological treatment of sediments contaminated by polycyclic aromatic hydrocarbons (PAHs) was evaluated through an experimental study. A bench-scale Sediment Slurry Sequencing Batch Reactor (SS-SBR) was fed with river sediments contaminated by a PAH mixture made by fluorene, anthracene, pyrene and crysene. The process performance was evaluated under different operating conditions, obtained by modifying the influent organic load, the feed composition and the hydraulic residence time. Measurements of the Oxygen Uptake Rates (OURs) provided useful insights on the biological kinetics occurring in the SS-SBR, suggesting the minimum applied cycle time-length of 7 days could be eventually halved, as also confirmed by the trend observed in the volatile solid and total organic carbon data. The removal efficiencies gradually improved during the SS-SBR operation, achieving at the end of the study rather constant removal rates above 80% for both 3-rings PAHs (fluorene and anthracene) and 4-ring PAHs (pyrene and crysene) for an inlet total PAH concentration of 70 mg/kg as dry weight (dw).

Total Weight and Axle Loads of Truck Units in the Transport of Timber Depending on the Timber Cargo

Directory of Open Access Journals (Sweden)

Grzegorz Trzciński

2018-03-01

Full Text Available When transporting timber, the high variability of species, assortments and moisture content of the wood raw material does not allow the weight of the transported timber to be precisely determined. This often contributes to the excessive weight loading of the entire truck unit. The aim of the research is to present the variability of the total weight of truck units with wood cargoes (GVW—gross vehicle weight depending on the weight of the empty unit and the transported timber load, as well as to analyze the changes in GVW, unit loads of wood and load on individual truck unit axles depending on the season. This study analyzes the total weight of truck units for 376 transports of Scots pine timber at different times of the year. The total weight of the truck units depends on the weight of an empty unit and the weight of the load. GVW was determined by using a weighbridge to weigh the vehicles and then the empty unit after unloading. The weight of the load was obtained as the difference between GVW and the tare. It was found that GVW differed significantly depending on the truck unit used, ranging from 43.60–58.80 Mg, often exceeding permissible limits for public roads. The individual axle loads for various truck units were also analyzed. The obtained results indicate that these loads are more equally distributed in the case of five-axle trucks compared to six-axle ones.

Gis Approach to Estimation of the Total Phosphorous Transfer in the Pilica River Lowland Catchment

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Magnuszewski Artur

2014-09-01

Full Text Available In this paper, the Pilica River catchment (central Poland is analyzed with a focus on understanding the total phosphorous transfer along the river system which also contains the large artificial Sulejów Reservoir. The paper presents a GIS method for estimating the total phosphorous (TP load from proxy data representing sub-catchment land use and census data. The modelled load of TP is compared to the actual transfer of TP in the Pilica River system. The results shows that the metrics of connectivity between river system and dwelling areas as well as settlement density in the sub-catchments are useful predictors of the total phosphorous load. The presence of a large reservoir in the middle course of the river can disrupt nutrient transport along a river continuum by trapping and retaining suspended sediment and its associated TP load. Analysis of the indirect estimation of TP loads with the GIS analysis can be useful for identifying beneficial reservoir locations in a catchment. The study has shown that the Sulejów Reservoir has been located in a subcatchment with a largest load of the TP, and this feature helps determine the problem of reservoir eutrphication

Estimation of sediment sources using selected chemical tracers in the Perry lake basin, Kansas, USA

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Juracek, K.E.; Ziegler, A.C.

2009-01-01

The ability to achieve meaningful decreases in sediment loads to reservoirs requires a determination of the relative importance of sediment sources within the contributing basins. In an investigation of sources of fine-grained sediment (clay and silt) within the Perry Lake Basin in northeast Kansas, representative samples of channel-bank sources, surface-soil sources (cropland and grassland), and reservoir bottom sediment were collected, chemically analyzed, and compared. The samples were sieved to isolate the phosphorus), organic and total carbon, 25 trace elements, and the radionuclide cesium-137 (137Cs). On the basis of substantial and consistent compositional differences among the source types, total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), and 137Cs were selected for use in the estimation of sediment sources. To further account for differences in particle-size composition between the sources and the reservoir bottom sediment, constituent ratio and clay-normalization techniques were used. Computed ratios included TOC to TN, TOC to TP, and TN to TP. Constituent concentrations (TN, TP, TOC) and activities (137Cs) were normalized by dividing by the percentage of clay. Thus, the sediment-source estimations involved the use of seven sediment-source indicators. Within the Perry Lake Basin, the consensus of the seven indicators was that both channel-bank and surface-soil sources were important in the Atchison County Lake and Banner Creek Reservoir subbasins, whereas channel-bank sources were dominant in the Mission Lake subbasin. On the sole basis of 137Cs activity, surface-soil sources contributed the most fine-grained sediment to Atchison County Lake, and channel-bank sources contributed the most fine-grained sediment to Banner Creek Reservoir and Mission Lake. Both the seven-indicator consensus and 137Cs indicated that channel-bank sources were dominant for Perry Lake and that channel-bank sources increased in importance with distance

Spatial and temporal variations in landscape evolution: historic and longer-term sediment flux through global catchments

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Covault, Jacob A.; Craddock, William H.; Romans, Brian W.; Fildani, Andrea; Gosai, Mayur

2013-01-01

Sediment generation and transport through terrestrial catchments influence soil distribution, geochemical cycling of particulate and dissolved loads, and the character of the stratigraphic record of Earth history. To assess the spatiotemporal variation in landscape evolution, we compare global compilations of stream gauge–derived () and cosmogenic radionuclide (CRN)–derived (predominantly 10Be; ) denudation of catchments (mm/yr) and sediment load of rivers (Mt/yr). Stream gauges measure suspended sediment loads of rivers during several to tens of years, whereas CRNs provide catchment-integrated denudation rates at 102–105-yr time scales. Stream gauge–derived and CRN-derived sediment loads in close proximity to one another (temporary storage of sediment in flood plains can provide stream gauge–based sediment loads and denudation rates that are applicable over longer periods than the durations of gauge measurements. The buffering capacity of catchments also has implications for interpreting the stratigraphic record; delayed sediment transfer might complicate the stratigraphic record of external forcings and catchment modification.

Accelerated Rates of Nitrogen Cycling and N2O Production in Salt Marsh Sediments due to Long-Term Fertilization

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Peng, X.; Ji, Q.; Angell, J.; Kearns, P.; Bowen, J. L.; Ward, B. B.

2014-12-01

Intensified sedimentary production of nitrous oxide (N2O), one of the most potent greenhouse gases, is one of the many possible environmental consequences of elevated nitrogen (N) loading into estuarine ecosystems. This study investigates the response to over 40 years of fertilization of nitrogen removal processes in the sediments of the Great Sippewissett Marsh in Falmouth, MA. Sediment slurries were incubated (1.5 hr) with trace amounts (fertilized sediments (0.89 nmol hr-1 g-1 wet weight) was 30-fold higher than in unfertilized sediments. The ratio of N2O to N2 production was also significantly higher in fertilized sediments (2.9%) than in unfertilized sediments (1.2%). This highlights the disproportionally large effect of long-term fertilization on N2O production in salt marsh sediments. The reduced oxygen level and higher ammonium concentrations in situ probably contributed to the significant rise in N2O production as a result of long-term fertilization. When detected, anammox and coupled nitrification-denitrification accounted for 10% and 14% of the total N2 production in fertilized sediments (30.5 nmol hr-1 g-1 wet weight), respectively, whereas neither was detected in unfertilized sediments. Thus these experiments indicate that N loading has important effects on multiple N cycle processes that result in N loss and N2O production.

A GUIDED SWAT MODEL APPLICATION ON SEDIMENT YIELD MODELING IN PANGANI RIVER BASIN: LESSONS LEARNT

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Preksedis Marco Ndomba

2008-12-01

Full Text Available The overall objective of this paper is to report on the lessons learnt from applying Soil and Water Assessment Tool (SWAT in a well guided sediment yield modelling study. The study area is the upstream of Pangani River Basin (PRB, the Nyumba Ya Mungu (NYM reservoir catchment, located in the North Eastern part of Tanzania. It should be noted that, previous modeling exercises in the region applied SWAT with preassumption that inter-rill or sheet erosion was the dominant erosion type. In contrast, in this study SWAT model application was guided by results of analysis of high temporal resolution of sediment flow data and hydro-meteorological data. The runoff component of the SWAT model was calibrated from six-years (i.e. 1977–1982 of historical daily streamflow data. The sediment component of the model was calibrated using one-year (1977–1988 daily sediment loads estimated from one hydrological year sampling programme (between March and November, 2005 rating curve. A long-term period over 37 years (i.e. 1969–2005 simulation results of the SWAT model was validated to downstream NYM reservoir sediment accumulation information. The SWAT model captured 56 percent of the variance (CE and underestimated the observed daily sediment loads by 0.9 percent according to Total Mass Control (TMC performance indices during a normal wet hydrological year, i.e., between November 1, 1977 and October 31, 1978, as the calibration period. SWAT model predicted satisfactorily the long-term sediment catchment yield with a relative error of 2.6 percent. Also, the model has identified erosion sources spatially and has replicated some erosion processes as determined in other studies and field observations in the PRB. This result suggests that for catchments where sheet erosion is dominant SWAT model may substitute the sediment-rating curve. However, the SWAT model could not capture the dynamics of sediment load delivery in some seasons to the catchment outlet.

A GUIDED SWAT MODEL APPLICATION ON SEDIMENT YIELD MODELING IN PANGANI RIVER BASIN: LESSONS LEARNT

Directory of Open Access Journals (Sweden)

Preksedis M. Ndomba

2008-01-01

Full Text Available The overall objective of this paper is to report on the lessons learnt from applying Soil and Water Assessment Tool (SWAT in a well guided sediment yield modelling study. The study area is the upstream of Pangani River Basin (PRB, the Nyumba Ya Mungu (NYM reservoir catchment, located in the North Eastern part of Tanzania. It should be noted that, previous modeling exercises in the region applied SWAT with preassumption that inter-rill or sheet erosion was the dominant erosion type. In contrast, in this study SWAT model application was guided by results of analysis of high temporal resolution of sediment flow data and hydro-meteorological data. The runoff component of the SWAT model was calibrated from six-years (i.e. 1977¿1982 of historical daily streamflow data. The sediment component of the model was calibrated using one-year (1977-1988 daily sediment loads estimated from one hydrological year sampling programme (between March and November, 2005 rating curve. A long-term period over 37 years (i.e. 1969-2005 simulation results of the SWAT model was validated to downstream NYM reservoir sediment accumulation information. The SWAT model captured 56 percent of the variance (CE and underestimated the observed daily sediment loads by 0.9 percent according to Total Mass Control (TMC performance indices during a normal wet hydrological year, i.e., between November 1, 1977 and October 31, 1978, as the calibration period. SWAT model predicted satisfactorily the long-term sediment catchment yield with a relative error of 2.6 percent. Also, the model has identified erosion sources spatially and has replicated some erosion processes as determined in other studies and field observations in the PRB. This result suggests that for catchments where sheet erosion is dominant SWAT model may substitute the sediment-rating curve. However, the SWAT model could not capture the dynamics of sediment load delivery in some seasons to the catchment outlet.

Floodplains as a source of fine sediment in grazed landscapes: tracing the source of suspended sediment in the headwaters of an intensively managed agricultural landscape

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Yu, M.; Rhoads, B. L.; Stumpf, A.

2017-12-01

The flux of fine sediment within agricultural watersheds is an important factor determining the environmental quality of streams and rivers. Despite this importance, the contributions of sediment sources to suspended sediment loads within intensively managed agricultural watersheds remain poorly understood. This study assesses the provenance of fine suspended sediment in the headwater portion of a river flowing through an agricultural landscape in Illinois. Sediment source samples were collected from five potential sources: streambanks, forested floodplain, grassland, and grazed floodplains. Event-based and aggregated suspended sediment samples were collected from the stream at the watershed outlet. Quantitative geochemical fingerprinting techniques and a mixing model were employed to estimate the relative contributions of sediment from five potential sources to the suspended sediment loads. Organic matter content, trace elements, and fallout radionuclides were used as potential tracers. Principal Component analysis was employed to complement the results and Monte Carlo random sampling routine was used to test the uncertainty in estimated contributions of sources to in-stream sediment loads. Results indicate that the majority of suspended sediment is derived from streambanks and grazed floodplains. Erosion of the floodplain both by surface runoff and by streambank erosion from lateral channel migration contributes to the production of fine sediment within the stream system. These results suggest that human activities, in this case grazing, have converted portions of floodplains, normally net depositional environments, into sources of fine sediments. Efforts to reduce fluxes of fine sediment in this intensively managed landscape should focus on degraded floodplain surfaces and eroding channel banks within heavily grazed reaches of the stream.

Influence of land use configurations on river sediment pollution.

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Liu, An; Duodu, Godfred O; Goonetilleke, Ashantha; Ayoko, Godwin A

2017-10-01

Land use is an influential factor in river sediment pollution. However, land use type alone is found to be inadequate to explain pollutant contributions to the aquatic environment since configurations within the same land use type such as land cover and development layout could also exert an important influence. Consequently, this paper discusses a research study, which consisted of an in-depth investigation into the relationship between land use type and river sediment pollution by introducing robust parameters that represent configurations within the primary land use types. Urban water pollutants, namely, nutrients, total carbon, polycyclic aromatic hydrocarbons and metals were investigated in the study. The outcomes show that higher patch density and more diverse land use development forms contribute relatively greater pollutant loads to receiving waters and consequently leading to higher sediment pollution. The study outcomes are expected to contribute essential knowledge for creating robust management strategies to minimise waterway pollution and thereby protect the health of aquatic ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sediment Buffering and Transport in the Holocene Indus River System

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Clift, P. D.; Giosan, L.; Henstock, T.; Tabrez, A. R.; Vanlaningham, S.; Alizai, A. H.; Limmer, D. R.; Danish, M.

2009-12-01

Submarine fans are the largest sediment bodies on Earth and potentially hold records of erosion that could be used to assess the response of continents to changing climate in terms of both physical erosion and chemical weathering. However, buffering between the mountain sources and the abyssal plain may make detailed correlation of climate and erosion records difficult. We investigated the nature of sediment transport in the Indus drainage in SW Asia. Through trenching in the flood plain, drilling in the delta and new seismic and coring data from the shelf and canyon we can now constrain sediment transport from source to sink since the Last Glacial Maximum (LGM). The Indus was affected by intensification of the summer monsoon during the Early Holocene and subsequent weakening since ca. 8 ka. Sediment delivery to the delta was very rapid at 12-8 ka, but slowed along with the weakening monsoon. At the LGM erosion in the Karakoram dominated the supply of sandy material, while the proportion of Lesser Himalayan flux increased with strengthening summer rainfall after 12 ka. Total load also increased at that time. Since 5 ka incision of rivers into the upper parts of the flood plain has reworked Lower Holocene sediments, although the total flux slowed. Coring in the Indus canyon shows that sediment has not reached the lower canyon since ca. 7 ka, but that sedimentation has recently been very rapid in the head of the canyon. We conclude that variations in sealevel and terrestrial climate have introduced a lag of at least 7 k.y. into the deep sea fan record and that monsoon strength is a primary control on whether sediment is stored or released in the flood plain.

Protecting the Green Behind the Gold: Catchment-Wide Restoration Efforts Necessary to Achieve Nutrient and Sediment Load Reduction Targets in Gold Coast City, Australia

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Waltham, Nathan J.; Barry, Michael; McAlister, Tony; Weber, Tony; Groth, Dominic

2014-10-01

The Gold Coast City is the tourist center of Australia and has undergone rapid and massive urban expansion over the past few decades. The Broadwater estuary, in the heart of the City, not only offers an array of ecosystems services for many important aquatic wildlife species, but also supports the livelihood and lifestyles of residents. Not surprisingly, there have been signs of imbalance between these two major services. This study combined a waterway hydraulic and pollutant transport model to simulate diffuse nutrient and sediment loads under past and future proposed land-use changes. A series of catchment restoration initiatives were modeled in an attempt to define optimal catchment scale restoration efforts necessary to protect and enhance the City's waterways. The modeling revealed that for future proposed development, a business as usual approach to catchment management will not reduce nutrient and sediment loading sufficiently to protect the community values. Considerable restoration of upper catchment tributaries is imperative, combined with treatment of stormwater flow from intensively developed sub-catchment areas. Collectively, initiatives undertaken by regulatory authorities to date have successfully reduced nutrient and sediment loading reaching adjoining waterways, although these programs have been ad hoc without strategic systematic planning and vision. Future conservation requires integration of multidisciplinary science and proactive management driven by the high ecological, economical, and community values placed on the City's waterways. Long-term catchment restoration and conservation planning requires an extensive budget (including political and societal support) to handle ongoing maintenance issues associated with scale of restoration determined here.

Sediment Transport Model for a Surface Irrigation System

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Damodhara R. Mailapalli

2013-01-01

Full Text Available Controlling irrigation-induced soil erosion is one of the important issues of irrigation management and surface water impairment. Irrigation models are useful in managing the irrigation and the associated ill effects on agricultural environment. In this paper, a physically based surface irrigation model was developed to predict sediment transport in irrigated furrows by integrating an irrigation hydraulic model with a quasi-steady state sediment transport model to predict sediment load in furrow irrigation. The irrigation hydraulic model simulates flow in a furrow irrigation system using the analytically solved zero-inertial overland flow equations and 1D-Green-Ampt, 2D-Fok, and Kostiakov-Lewis infiltration equations. Performance of the sediment transport model was evaluated for bare and cropped furrow fields. The results indicated that the sediment transport model can predict the initial sediment rate adequately, but the simulated sediment rate was less accurate for the later part of the irrigation event. Sensitivity analysis of the parameters of the sediment module showed that the soil erodibility coefficient was the most influential parameter for determining sediment load in furrow irrigation. The developed modeling tool can be used as a water management tool for mitigating sediment loss from the surface irrigated fields.

Suspended sediment and sediment-associated contaminants in San Francisco Bay

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Schoellhamer, D.H.; Mumley, T.E.; Leatherbarrow, J.E.

2007-01-01

Water-quality managers desire information on the temporal and spatial variability of contaminant concentrations and the magnitudes of watershed and bed-sediment loads in San Francisco Bay. To help provide this information, the Regional Monitoring Program for Trace Substances in the San Francisco Estuary (RMP) takes advantage of the association of many contaminants with sediment particles by continuously measuring suspended-sediment concentration (SSC), which is an accurate, less costly, and more easily measured surrogate for several trace metals and organic contaminants. Continuous time series of SSC are collected at several sites in the Bay. Although semidiurnal and diurnal tidal fluctuations are present, most of the variability of SSC occurs at fortnightly, monthly, and semiannual tidal time scales. A seasonal cycle of sediment inflow, wind-wave resuspension, and winnowing of fine sediment also is observed. SSC and, thus, sediment-associated contaminants tend to be greater in shallower water, at the landward ends of the Bay, and in several localized estuarine turbidity maxima. Although understanding of sediment transport has improved in the first 10 years of the RMP, determining a simple mass budget of sediment or associated contaminants is confounded by uncertainties regarding sediment flux at boundaries, change in bed-sediment storage, and appropriate modeling techniques. Nevertheless, management of sediment-associated contaminants has improved greatly. Better understanding of sediment and sediment-associated contaminants in the Bay is of great interest to evaluate the value of control actions taken and the need for additional controls. ?? 2007 Elsevier Inc. All rights reserved.

Spatiotemporal distribution and mass loadings of perfluoroalkyl substances in the Yangtze River of China.

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Pan, Chang-Gui; Ying, Guang-Guo; Zhao, Jian-Liang; Liu, You-Sheng; Jiang, Yu-Xia; Zhang, Qian-Qian

2014-09-15

A systematic investigation into contamination profiles of eighteen perfluoroalkyl substances (PFASs) in both surface water and sediments of Yangtze River was carried out by using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in summer and winter of 2013. The total concentrations of the PFASs in the water and sediment of Yangtze River ranged from 2.2 to 74.56 ng/L and 0.05 to 1.44 ng/g dry weights (dw), respectively. The PFAS concentrations were correlated to some selected water quality parameters such as pH, total phosphorus (TP), total nitrogen (TN) and conductivity in water, and some sediment properties, such as total organic carbon (TOC), TP, and TN in sediment. The monitoring results for the water and sediment samples showed no obvious seasonal variations. Among the selected 18 PFASs, perfluorooctanoic acid (PFOA) was the dominant PFAS compound found both in water and sediment for the two seasons with its maximum concentration of 18.03 ng/L in water and 0.72 ng/g in sediment, followed by perfluorobutane sulfonic acid (PFBS) with its maximum concentration of 41.9 ng/L in water in Wuhan, whereas the lowest concentrations of PFASs were observed at Poyang lake. The annual loadings of PFOA, perfluorohexanoic acid (PFHxA), PFBS, perfluorooctane sulfonic acid (PFOS) and the total PFASs in the Yangtze River were 6.8 tons, 2.2 tons, 8.2 tons, 0.88 tons, and 20.7 tons, respectively. Wuhan and Er'zhou of Hubei contributed the most amounts of PFASs into the Yangtze River. A correlation was found between some PFASs, for example PFBS and PFOS, which suggests that both of these PFASs originate from common sources in the region. Copyright © 2014 Elsevier B.V. All rights reserved.

Chemical and physical properties of the surface sea sediments at the Olkiluoto offshore, South-Western Finland

International Nuclear Information System (INIS)

Lahdenperae, A.-M.; Keskinen, A.

2011-11-01

Due to land uplift, the present sea sediments near Olkiluoto will be future land areas, and thus important for the transport of possible releases from nuclear waste repositories at the site. Coastal areas are the transition zones between land and sea, and also potential sites for deep groundwater discharge. The geochemical properties of the surface sediments at the Olkiluoto sea area are summarised in this report. Thirteen sediment samples were cored during the R/V Geomari cruise in autumn 2008. In addition, surface sediment samples from six transects, altogether 57 cores, were taken near the Olkiluoto shoreline by diving in the summer of 2008. The analysis procedure included pH, moisture, dry matter, ash and LOI contents, grain size distribution, carbon and nitrogen analyses and the total concentrations of thirtythree elements. The lateral and vertical distribution of element concentrations, especially heavy metals, is caused by variations in transport and sedimentation patterns of particulate matter, in the occurrence of migration processes and bonding types. The distribution pattern in most of the elements is strongly linked to that of organic matter, carbon and fine-grained material contents. The sediments are strongly enriched by some of the studied elements possibly due to anthropogenic load, while others are only moderately or slightly present. However, the source of different natural and anthropogenic loads is not easy to point out. (orig.)

Assessing Sediment Yield and the Effect of Best Management Practices on Sediment Yield Reduction for Tutuila Island, American Samoa

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Leta, O. T.; Dulai, H.; El-Kadi, A. I.

2017-12-01

Upland soil erosion and sedimentation are the main threats for riparian and coastal reef ecosystems in Pacific islands. Here, due to small size of the watersheds and steep slope, the residence time of rainfall runoff and its suspended load is short. Fagaalu bay, located on the island of Tutuila (American Samoa) has been identified as a priority watershed, due to degraded coral reef condition and reduction of stream water quality from heavy anthropogenic activity yielding high nutrients and sediment loads to the receiving water bodies. This study aimed to estimate the sediment yield to the Fagaalu stream and assess the impact of Best Management Practices (BMP) on sediment yield reduction. For this, the Soil and Water Assessment Tool (SWAT) model was applied, calibrated, and validated for both daily streamflow and sediment load simulation. The model also estimated the sediment yield contributions from existing land use types of Fagaalu and identified soil erosion prone areas for introducing BMP scenarios in the watershed. Then, three BMP scenarios, such as stone bund, retention pond, and filter strip were treated on bare (quarry area), agricultural, and shrub land use types. It was found that the bare land with quarry activity yielded the highest annual average sediment yield of 133 ton per hectare (t ha-1) followed by agriculture (26.1 t ha-1) while the lowest sediment yield of 0.2 t ha-1 was estimated for the forested part of the watershed. Additionally, the bare land area (2 ha) contributed approximately 65% (207 ha) of the watershed's sediment yield, which is 4.0 t ha-1. The latter signifies the high impact as well as contribution of anthropogenic activity on sediment yield. The use of different BMP scenarios generally reduced the sediment yield to the coastal reef of Fagaalu watershed. However, treating the quarry activity area with stone bund showed the highest sediment yield reduction as compared to the other two BMP scenarios. This study provides an estimate

Sediment loads and transport at constructed chutes along the Missouri River - Upper Hamburg Chute near Nebraska City, Nebraska, and Kansas Chute near Peru, Nebraska

Science.gov (United States)

Densmore, Brenda K.; Rus, David L.; Moser, Matthew T.; Hall, Brent M.; Andersen, Michael J.

2016-02-04

estimate streamflow within each chute. The sampling design was developed to understand the suspended-sediment differences within each chute and between the chute and the Missouri River main channel during discrete sampling. The sampling design also allowed for site-specific surrogate relations between SSC and turbidity to be developed, which could be used to compute real-time estimates of SSC and sediment loads within the chutes. Real-time estimates of SSC and sediment loads enable a better understanding of sediment transport within the chutes during times when physical samples are not collected, including periods of high flow.

Variation in flow and suspended sediment transport in a montane river affected by hydropeaking and instream mining

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Béjar, M.; Vericat, D.; Batalla, R. J.; Gibbins, C. N.

2018-06-01

The temporal and spatial variability of water and sediment loads of rivers is controlled by a suite of factors whose individual effects are often difficult to disentangle. While land use changes and localised human activities such as instream mining and hydropeaking alter water and sediment transfer, tributaries naturally contribute to discharge and sediment load of mainstem rivers, and so may help compensate upstream anthropogenic factors. The work presented here aimed to assess water and the sediment transfer in a river reach affected by gravel extraction and hydropeaking, set against a backdrop of changes to the supply of water and sediment from tributaries. Discharge and suspended sediment transport were monitored during two average hydrological years at three cross-sections along a 10-km reach of the upper River Cinca, in the Southern Pyrenees. Water and sediment loads differed substantially between the reaches. The upper reach showed a largely torrential discharge regime, controlled mainly by floods, and had high but variable water and sediment loads. The middle reach was influenced markedly by hydropeaking and tributary inflows, which increased its annual water yield four-fold. Suspended sediment load in this reach increased by only 25% compared to upstream, indicating that dilution predominated. In the lowermost section, while discharge remained largely unaltered, sediment load increased appreciably as a result of changes to sediment availability from instream mining and inputs from tributaries. At the reach scale, snowmelt and summer and autumn thunderstorms were responsible for most of the water yield, while flood flows determined the magnitude and transport of the sediment load. The study highlights that a combination of natural and human factors control the spatial and temporal transfer of water and sediment in river channels and that, depending on their geographic location and effect-size, can result in marked variability even over short downstream

Sediment sources in the Upper Severn catchment: a fingerprinting approach

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A. L. Collins

1997-01-01

Full Text Available Suspended sediment sources in the Upper Severn catchment are quantified using a composite fingerprinting technique combining statistically-verified signatures with a multivariate mixing model. Composite fingerprints are developed from a suite of diagnostic properties comprising trace metal (Fe, Mn, AI, heavy metal (Cu, Zn, Pb, Cr, Co, Ni, base cation (Na, Mg, Ca, K, organic (C, N, radiometric (137Cs, 210Pb, and other (total P determinands. A numerical mixing model, to compare the fingerprints of contemporary catchment source materials with those of fluvial suspended sediment in transit and those of recent overbank floodplain deposits, provides a means of quantifying present and past sediment sources respectively. Sources are classified in terms of eroding surface soils under different land uses and channel banks. Eroding surface soils are the most important source of the contemporary suspended sediment loads sampled at the Institute of Hydrology flow gauging stations at Plynlimon and at Abermule. The erosion of forest soils, associated with the autumn and winter commercial activities of the Forestry Commission, is particularly evident. Reconstruction of sediment provenance over the recent past using a sediment core from the active river floodpiain at Abermule, in conjunction with a 137Cs chronology, demonstrates the significance of recent phases of afforestation and deforestation for accelerated catchment soil erosion.

Suspended sediment, turbidity, and stream water temperature in the Sauk River Basin, western Washington, water years 2012-16

Science.gov (United States)

Jaeger, Kristin L.; Curran, Christopher A.; Anderson, Scott W.; Morris, Scott T.; Moran, Patrick W.; Reams, Katherine A.

2017-11-01

The Sauk River is a federally designated Wild and Scenic River that drains a relatively undisturbed landscape along the western slope of the North Cascade Mountain Range, Washington, which includes the glaciated volcano, Glacier Peak. Naturally high sediment loads characteristic of basins draining volcanoes like Glacier Peak make the Sauk River a dominant contributor of sediment to the downstream main stem river, the Skagit River. Additionally, the Sauk River serves as important spawning and rearing habitat for several salmonid species in the greater Skagit River system. Because of the importance of sediment to morphology, flow-conveyance, and ecosystem condition, there is interest in understanding the magnitude and timing of suspended sediment and turbidity from the Sauk River system and its principal tributaries, the White Chuck and Suiattle Rivers, to the Skagit River.Suspended-sediment measurements, turbidity data, and water temperature data were collected at two U.S. Geological Survey streamgages in the upper and middle reaches of the Sauk River over a 4-year period extending from October 2011 to September 2015, and at a downstream location in the lower river for a 5-year period extending from October 2011 to September 2016. Over the collective 5-year study period, mean annual suspended-sediment loads at the three streamgages on the upper, middle, and lower Sauk River streamgages were 94,200 metric tons (t), 203,000 t, and 940,000 t streamgages, respectively. Fine (smaller than 0.0625 millimeter) total suspended-sediment load averaged 49 percent at the upper Sauk River streamgage, 42 percent at the middle Sauk River streamgage, and 34 percent at the lower Sauk River streamgage.

An improved method for quantitatively measuring the sequences of total organic carbon and black carbon in marine sediment cores

Science.gov (United States)

Xu, Xiaoming; Zhu, Qing; Zhou, Qianzhi; Liu, Jinzhong; Yuan, Jianping; Wang, Jianghai

2018-01-01

Understanding global carbon cycle is critical to uncover the mechanisms of global warming and remediate its adverse effects on human activities. Organic carbon in marine sediments is an indispensable part of the global carbon reservoir in global carbon cycling. Evaluating such a reservoir calls for quantitative studies of marine carbon burial, which closely depend on quantifying total organic carbon and black carbon in marine sediment cores and subsequently on obtaining their high-resolution temporal sequences. However, the conventional methods for detecting the contents of total organic carbon or black carbon cannot resolve the following specific difficulties, i.e., (1) a very limited amount of each subsample versus the diverse analytical items, (2) a low and fluctuating recovery rate of total organic carbon or black carbon versus the reproducibility of carbon data, and (3) a large number of subsamples versus the rapid batch measurements. In this work, (i) adopting the customized disposable ceramic crucibles with the microporecontrolled ability, (ii) developing self-made or customized facilities for the procedures of acidification and chemothermal oxidization, and (iii) optimizing procedures and carbon-sulfur analyzer, we have built a novel Wang-Xu-Yuan method (the WXY method) for measuring the contents of total organic carbon or black carbon in marine sediment cores, which includes the procedures of pretreatment, weighing, acidification, chemothermal oxidation and quantification; and can fully meet the requirements of establishing their highresolution temporal sequences, whatever in the recovery, experimental efficiency, accuracy and reliability of the measurements, and homogeneity of samples. In particular, the usage of disposable ceramic crucibles leads to evidently simplify the experimental scenario, which further results in the very high recovery rates for total organic carbon and black carbon. This new technique may provide a significant support for

Anomalous South Pacific lithosphere dynamics derived from new total sediment thickness estimates off the West Antarctic margin

Science.gov (United States)

Wobbe, Florian; Lindeque, Ansa; Gohl, Karsten

2014-12-01

Paleotopographic models of the West Antarctic margin, which are essential for robust simulations of paleoclimate scenarios, lack information on sediment thickness and geodynamic conditions, resulting in large uncertainties. A new total sediment thickness grid spanning the Ross Sea-Amundsen Sea-Bellingshausen Sea basins is presented and is based on all the available seismic reflection, borehole, and gravity modeling data offshore West Antarctica. This grid was combined with NGDC's global 5 arc minute grid of ocean sediment thickness (Whittaker et al., 2013) and extends the NGDC grid further to the south. Sediment thickness along the West Antarctic margin tends to be 3-4 km larger than previously assumed. The sediment volume in the Bellingshausen, Amundsen, and Ross Sea basins amounts to 3.61, 3.58, and 2.78 million km3, respectively. The residual basement topography of the South Pacific has been revised and the new data show an asymmetric trend over the Pacific-Antarctic Ridge. Values are anomalously high south of the spreading ridge and in the Ross Sea area, where the topography seems to be affected by persistent mantle processes. In contrast, the basement topography offshore Marie Byrd Land cannot be attributed to dynamic topography, but rather to crustal thickening due to intraplate volcanism. Present-day dynamic topography models disagree with the presented revised basement topography of the South Pacific, rendering paleotopographic reconstructions with such a limited dataset still fairly uncertain.

Impact assessment of rainfall-vegetation on sedimentation and predicting erosion-prone region by GIS and RS

Directory of Open Access Journals (Sweden)

Mahboob Alam

2016-03-01

Full Text Available Water reservoirs are facing universal sedimentation problems worldwide. Land covers, whether natural or manmade, eventually change, and the vegetation cover and rainfall have a great effect on the sediment load. Traditional techniques for analysing this problem are time-consuming and spatially limited. Remote sensing (RS provides a convenient way to observe land cover changes, and geographic information system (GIS provides tools for geographic analysis. This study demonstrates a GIS-based methodology for calculating the impact of vegetation and rainfall on the sediment load using remotely sensed data. Moderate resolution imaging spectroradiometer data were used to observe temporal changes in the vegetation-cover area of the watershed surface. The total drainage area for the reservoir was calculated from shuttle radar topographic mission data. The annual rainfall amount was used to compute the annual available rainwater for the watershed, and the impact of the annual available rainwater on the vegetation-covered area was determined. In addition, areas that were adding sedimentation to the reservoir were identified. An inverse relationship between the rainfall and vegetation cover was observed, clearly showing the triggering of erosion.

Molecular diagnosis of bacterial vaginosis: Does adjustment for total bacterial load or human cellular content improve diagnostic performance?

Science.gov (United States)

Plummer, E L; Garland, S M; Bradshaw, C S; Law, M G; Vodstrcil, L A; Hocking, J S; Fairley, C K; Tabrizi, S N

2017-02-01

We investigated the utility of quantitative PCR assays for diagnosis of bacterial vaginosis and found that while the best model utilized bacterial copy number adjusted for total bacterial load (sensitivity=98%, specificity=93%, AUC=0.95[95%CI=0.93,0.97]), adjusting for total bacterial or human cell load did not consistently increase the diagnostic performance of the assays. Copyright © 2017 Elsevier B.V. All rights reserved.

Modeling the Effects of Reservoir Releases on the Bed Material Sediment Flux of the Colorado River in western Colorado and eastern Utah

Science.gov (United States)

Pitlick, J.; Bizzi, S.; Schmitt, R. J. P.

2017-12-01

Warm-water reaches of the upper Colorado River have historically provided important habitat for four endangered fishes. Over time these habitats have been altered or lost due to reductions in peak flows and sediment loads caused by reservoir operations. In an effort to reverse these trends, controlled reservoir releases are now used to enhance sediment transport and restore channel complexity. In this presentation, we discuss the development of a sediment routing model designed to assess how changes in water and sediment supply can affect the mass balance of sediment. The model is formulated for ten reaches of the Colorado River spanning 250 km where values of bankfull discharge, width, and reach-average slope have been measured. Bed surface grain size distributions (GSDs) have also been measured throughout the study area; these distributions are used as a test of the model, not as input, except as an upstream boundary condition. In modeling fluxes and GSDs, we assume that the bed load transport capacity is determined by local hydraulic conditions and bed surface grain sizes. Estimates of the bankfull bed load transport capacity in each reach are computed for 14 size fractions of the surface bed material, and the fractional transport rates are summed to get the total transport capacity. In the adjacent reach, fluxes of each size fraction from upstream are used to determine the mean grain size, and the fractional transport capacity of that reach. Calculations proceed downstream and illustrate how linked changes in discharge, shear stress and mean grain size affect (1) the total bed load transport capacity, and (2) the size distribution of the bed surface sediment. The results show that model-derived GSDs match measured GSDs very closely, except for two reaches in the lower part of the study area where slope is affected by uplift associated with salt diapirs; here the model significantly overestimates the transport capacity in relation to the supply. Except for these

Internal loading of phosphorus in western Lake Erie

Science.gov (United States)

Matisoff, Gerald; Kaltenberg, Eliza M.; Steely, Rebecca L.; Hummel, Stephanie K.; Seo, Jinyu; Gibbons, Kenneth J.; Bridgeman, Thomas B.; Seo, Youngwoo; Behbahani, Mohsen; James, William F.; Johnson, Laura; Doan, Phuong; Dittrich, Maria; Evans, Mary Anne; Chaffin, Justin D.

2016-01-01

This study applied eight techniques to obtain estimates of the diffusive flux of phosphorus (P) from bottom sediments throughout the western basin of Lake Erie. The flux was quantified from both aerobic and anaerobic incubations of whole cores; by monitoring the water encapsulated in bottom chambers; from pore water concentration profiles measured with a phosphate microelectrode, a diffusive equilibrium in thin films (DET) hydrogel, and expressed pore waters; and from mass balance and biogeochemical diagenetic models. Fluxes under aerobic conditions at summertime temperatures averaged 1.35 mg P/m2/day and displayed spatial variability on scales as small as a centimeter. Using two different temperature correction factors, the flux was adjusted to mean annual temperature yielding average annual fluxes of 0.43–0.91 mg P/m2/day and a western basin-wide total of 378–808 Mg P/year as the diffusive flux from sediments. This is 3–7% of the 11,000 Mg P/year International Joint Commission (IJC) target load for phosphorus delivery to Lake Erie from external sources. Using these average aerobic fluxes, the sediment contributes 3.0–6.3 μg P/L as a background internal contribution that represents 20–42% of the IJC Target Concentration of 15 μg P/L for the western basin. The implication is that this internal diffusive recycling of P is unlikely to trigger cyanobacterial blooms by itself but is sufficiently large to cause blooms when combined with external loads. This background flux may be also responsible for delayed response of the lake to any decrease in the external loading.

Estimation of Constituent Concentrations, Loads, and Yields in Streams of Johnson County, Northeast Kansas, Using Continuous Water-Quality Monitoring and Regression Models, October 2002 through December 2006

Science.gov (United States)

Rasmussen, Teresa J.; Lee, Casey J.; Ziegler, Andrew C.

2008-01-01

Johnson County is one of the most rapidly developing counties in Kansas. Population growth and expanding urban land use affect the quality of county streams, which are important for human and environmental health, water supply, recreation, and aesthetic value. This report describes estimates of streamflow and constituent concentrations, loads, and yields in relation to watershed characteristics in five Johnson County streams using continuous in-stream sensor measurements. Specific conductance, pH, water temperature, turbidity, and dissolved oxygen were monitored in five watersheds from October 2002 through December 2006. These continuous data were used in conjunction with discrete water samples to develop regression models for continuously estimating concentrations of other constituents. Continuous regression-based concentrations were estimated for suspended sediment, total suspended solids, dissolved solids and selected major ions, nutrients (nitrogen and phosphorus species), and fecal-indicator bacteria. Continuous daily, monthly, seasonal, and annual loads were calculated from concentration estimates and streamflow. The data are used to describe differences in concentrations, loads, and yields and to explain these differences relative to watershed characteristics. Water quality at the five monitoring sites varied according to hydrologic conditions; contributing drainage area; land use (including degree of urbanization); relative contributions from point and nonpoint constituent sources; and human activity within each watershed. Dissolved oxygen (DO) concentrations were less than the Kansas aquatic-life-support criterion of 5.0 mg/L less than 10 percent of the time at all sites except Indian Creek, which had DO concentrations less than the criterion about 15 percent of the time. Concentrations of suspended sediment, chloride (winter only), indicator bacteria, and pesticides were substantially larger during periods of increased streamflow. Suspended-sediment

Long-term Sediment Accumulation in Mid-channel Bars of the Upper Reach of the Lower Mississippi River.

Science.gov (United States)

Wang, B.; Xu, Y. J.

2016-02-01

A recent study reported that about 44% of the total Mississippi River suspended load reaching the Old River Control Structure (ORCS) was trapped upstream of the Gulf of Mexico by overbank storage and channel bed aggradation. Considering an average annual sediment load of 120 million metric tons passing ORCS to the Mississippi River main channel, the trapped sediment load would be equivalent to annually rebuilding 44-km2 coastal land of 1 meter in depth, assuming a sedimentation bulk density of 1.2 tons m-3. No study has yet demonstrated such a high sediment accumulation rate within the confined river channel or on a floodplain area that surrounds the only unleeved stretch ( 30-km long) of the Lower Mississippi River downstream of ORCS. In this study, we utilized satellite images taken from 1983 to 2013 and analyzed changes in surface area of nine major mid-channel and point bars over a 130-km river reach from ORCS to Baton Rouge. Using river stage records and the estimated surface areas, we developed a stage - surface area rating curve for each of the bars and estimated changes in bar volume over time. We found that more than half of the bars have grown, while the others have shrunken in the past three decades. As a whole, there was a substantial net gain of surface area and volume accretion. Sediment trapping was most prevalent during the spring floods, especially during the period from 2007 to 2011 when two large floods occurred. This paper presents the channel morphological change and sediment accumulation rates under different flow conditions, and discusses their implications for the current understanding and practices of the Mississippi River sediment diversion.

Sediment Transport Capacity and Channel Processes in a Humid Tropical Montane River - Rio Pacuare, Costa Rica

Science.gov (United States)

Lind, P.; McDowell, P. F.

2017-12-01

Investigating sediment transport capacity as well as the spatial and temporal variations of sediment flux are critical component of river research, especially for applications in resource management and conservation, hazards assessment and planning, and riverine ecology. The bedload fraction of sediment transported through montane rivers often defines channel and bed form processes. It is understood that humid tropical montane rivers are capable of producing some of the largest quantities of sediment per unit drainage area. Bedload flux reported on a few Southeast Asian humid tropical montane rivers show that bedload constituted 16-75% of the total sediment load - this is notably higher than the generally accepted 10% of a channel's sediment load. However, to date almost all of the research done on sediment transport in humid tropical systems has focused on suspended load. This study presents annual bedload transport rate estimates for six field sites distributed within 45 river kilometers (Rkm) of the montane portion of the Rio Pacuare, located in the Talamanca Mountains of Costa Rica. This research reveals that flows capable of mobilizing the D84 occur on average at least once but often multiple times a year in this river system. The Rio Pacuare has a sufficient supply of sediment to meet its high transport capacity needs. As a result, large active bars composed of imbricated boulders define channel form at moderate and low flows throughout the study area. Differences in the magnitude, as well as the spatial and temporal variations of sediment flux at each field site are discussed in relation to stream power, and annual/inter-annual precipitation patterns. A unique mix of field and remote sensing techniques were applied to address these questions and to overcome some of the challenges of tropical river research. For example, due to the large grain size and high stream energy, grain mobilization and validation of modeled shear stress requirements for transport

A reassessment of the suspended sediment load in the Madeira River basin from the Andes of Peru and Bolivia to the Amazon River in Brazil, based on 10 years of data from the HYBAM monitoring programme

Science.gov (United States)

Vauchel, Philippe; Santini, William; Guyot, Jean Loup; Moquet, Jean Sébastien; Martinez, Jean Michel; Espinoza, Jhan Carlo; Baby, Patrice; Fuertes, Oscar; Noriega, Luis; Puita, Oscar; Sondag, Francis; Fraizy, Pascal; Armijos, Elisa; Cochonneau, Gérard; Timouk, Franck; de Oliveira, Eurides; Filizola, Naziano; Molina, Jorge; Ronchail, Josyane

2017-10-01

The Madeira River is the second largest tributary of the Amazon River. It contributes approximately 13% of the Amazon River flow and it may contribute up to 50% of its sediment discharge to the Atlantic Ocean. Until now, the suspended sediment load of the Madeira River was not well known and was estimated in a broad range from 240 to 715 Mt yr-1. Since 2002, the HYBAM international network developed a new monitoring programme specially designed to provide more reliable data than in previous intents. It is based on the continuous monitoring of a set of 11 gauging stations in the Madeira River watershed from the Andes piedmont to the confluence with the Amazon River, and discrete sampling of the suspended sediment concentration every 7 or 10 days. This paper presents the results of the suspended sediment data obtained in the Madeira drainage basin during 2002-2011. The Madeira River suspended sediment load is estimated at 430 Mt yr-1 near its confluence with the Amazon River. The average production of the Madeira River Andean catchment is estimated at 640 Mt yr-1 (±30%), the corresponding sediment yield for the Andes is estimated at 3000 t km-2 yr-1 (±30%), and the average denudation rate is estimated at 1.20 mm yr-1 (±30%). Contrary to previous results that had mentioned high sedimentation rates in the Beni River floodplain, we detected no measurable sedimentation process in this part of the basin. On the Mamoré River basin, we observed heavy sediment deposition of approximately 210 Mt yr-1 that seem to confirm previous studies. But while these studies mentioned heavy sedimentation in the floodplain, we showed that sediment deposition occurred mainly in the Andean piedmont and immediate foreland in rivers (Parapeti, Grande, Pirai, Yapacani, Chimoré, Chaparé, Secure, Maniqui) with discharges that are not sufficiently large to transport their sediment load downstream in the lowlands.

Sediment contributions from floodplains and legacy sediments to Piedmont streams of Baltimore County, Maryland

Science.gov (United States)

Donovan, Mitchell; Miller, Andrew; Baker, Matthew; Gellis, Allen

2015-04-01

Disparity between watershed erosion rates and downstream sediment delivery has remained an important theme in geomorphology for many decades, with the role of floodplains in sediment storage as a common focus. In the Piedmont Province of the eastern USA, upland deforestation and agricultural land use following European settlement led to accumulation of thick packages of overbank sediment in valley bottoms, commonly referred to as legacy deposits. Previous authors have argued that legacy deposits represent a potentially important source of modern sediment loads following remobilization by lateral migration and progressive channel widening. This paper seeks to quantify (1) rates of sediment remobilization from Baltimore County floodplains by channel migration and bank erosion, (2) proportions of streambank sediment derived from legacy deposits, and (3) potential contribution of net streambank erosion and legacy sediments to downstream sediment yield within the Mid-Atlantic Piedmont. We calculated measurable gross erosion and deposition rates within the fluvial corridor along 40 valley segments from 18 watersheds with drainage areas between 0.18 and 155 km2 in Baltimore County, Maryland. We compared stream channel and floodplain morphology from lidar-based digital elevation data collected in 2005 with channel positions recorded on 1:2400 scale topographic maps from 1959-1961 in order to quantify 44-46 years of channel change. Sediment bulk density and particle size distributions were characterized from streambank and channel deposit samples and used for volume to mass conversions and for comparison with other sediment sources. Average annual lateral migration rates ranged from 0.04 to 0.19 m/y, which represented an annual migration of 2.5% (0.9-4.4%) channel width across all study segments, suggesting that channel dimensions may be used as reasonable predictors of bank erosion rates. Gross bank erosion rates varied from 43 to 310 Mg/km/y (median = 114) and were

40 CFR 130.7 - Total maximum daily loads (TMDL) and individual water quality-based effluent limitations.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Total maximum daily loads (TMDL) and individual water quality-based effluent limitations. 130.7 Section 130.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS WATER QUALITY PLANNING AND MANAGEMENT § 130.7 Total...

Study of polluted water mixing on sediment of Lahore canal

International Nuclear Information System (INIS)

Asim, M.

2016-01-01

People living in societies along the canals which pass through the urban areas, are adding domestic and industrial waste water and wastes into them like Lahore canal. This untreated industrial and municipal waste and contaminated water may become a risk to irrigation water quality and sediment moving in it in the form of suspended load. The results disclose that as suspended sediment concentration increases the pH value drops. Consequently it can be established from results that they are inversely related to each other but this behaviour is generally due to effect of rain water runoff. The suspended sediment content was at its highest during monsoon season. Similarly pH values varied considerably from limit of 6.5-8.4. Other water quality chemical parameters did not stray from their recommended limits. The dumping of waste water from pipes did not have any major effect on the water quality of the canal due to its less percentage to the total canal discharge. (author)

Human impact on erosion patterns and sediment transport in the Yangtze River

NARCIS (Netherlands)

Sun, Xilin; Li, Chang'an; Kuiper, K. F.; Zhang, Zengjie; Gao, Jianhua; Wijbrans, J. R.

2016-01-01

Sediment load in rivers is an indicator of erosional processes in the upstream river catchments. Understanding the origin and composition of the sediment load can help to assess the influence of natural processes and human activities on erosion. Tectonic uplift, precipitation and run-off, hill

Total petroleum hydrocarbons in sediments from the coastline and mangroves of the northern Persian Gulf.

Science.gov (United States)

Mohebbi-Nozar, Seyedeh Laili; Zakaria, Mohamad Pauzi; Ismail, Wan Ruslan; Mortazawi, Mohammad Seddiq; Salimizadeh, Maryam; Momeni, Mohammad; Akbarzadeh, Gholamali

2015-06-15

To provide baseline information for the marine ecosystem of Hormozgan province, the distribution of petroleum hydrocarbons was evaluated in 52 stations involved in the mangrove and coastline ecosystem. Coastline sampling sites included areas facing harbor, river, domestic and industrial discharge. Sediment samples were analyzed based on ultraviolet fluorescence spectroscopy. Petroleum hydrocarbons showed narrow variations ranging from non-detectable (ND) to 1.71 and from 0.2 to 0.63μg/g dry weight for coastline and mangrove sediments, respectively. The detected concentrations for total petroleum hydrocarbons were lower than guideline values for ecological risk. Furthermore, the minimum environmental risk was confirmed by background levels for the Persian Gulf, the Sea of Oman, and detected values for reference areas. The results were regarded as background data in the studied area, and, considering the rapid expansion of activities related to the petroleum industry in Hormozgan province, the continuous monitoring of pollutants is recommended. Copyright © 2015 Elsevier Ltd. All rights reserved.

Reduced phosphorus retention by anoxic bottom sediments after the remediation of an industrial acidified lake area: Indications from P, Al, and Fe sediment fractions.

Science.gov (United States)

Nürnberg, Gertrud K; Fischer, Rachele; Paterson, Andrew M

2018-06-01

Formerly acidified lakes and watersheds can become more productive when recovering from acidity, especially when exposed to anthropogenic disturbance and increased nutrient loading. Occasional toxic cyanobacterial blooms and other signs of eutrophication have been observed for a decade in lakes located in the Sudbury, Ontario, mining area that was severely affected by acid deposition before the start of smelter emission reductions in the 1970s. Oligotrophic Long Lake and its upstream lakes have been exposed to waste water input and development impacts from the City of Greater Sudbury and likely have a legacy of nutrient enrichment in their sediment. Based on observations from other published studies, we hypothesized that P, which was previously adsorbed by metals liberated during acidification caused by the mining activities, is now being released from the sediment as internal P loading contributing to increased cyanobacteria biomass. Support for this hypothesis includes (1) lake observations of oxygen depletion and hypolimnetic anoxia and slightly elevated hypolimnetic total P concentration and (2) P, Al, and Fe fractionation of two sediment layers (0-5, 5-10 cm), showing elevated concentrations of TP and iron releasable P (BD-fraction), decreased concentrations in fractions associated with Al, and fraction ratios indicating decreased sediment adsorption capacity. The comparison with two moderately enriched lakes within 200 km distance, but never directly affected by mining operations, supports the increasing similarity of Long Lake surficial sediment adsorption capacity with that of unaffected lakes. There is cause for concern that increased eutrophication including the proliferation of cyanobacteria of formerly acidic lakes is wide-spread and occurs wherever recovery coincides with anthropogenic disturbances and physical changes related to climate change. Copyright © 2018 Elsevier B.V. All rights reserved.

Sediment Budget in the Taiwan Strait with High Fluvial Sediment Inputs from Mountainous Rivers: New Observations and Synthesis

Directory of Open Access Journals (Sweden)

Shuh-Ji Kao

2008-01-01

Full Text Available The shallow Taiwan Strait at the southern opening of the East China Sea (ECS receives abundant sediments from turbid mountainous rivers in Taiwan. The volume of sediment is among the highest sediment yields on the global surface. This large amount of sediment discharged from modern Taiwan (range: 175 - 380 Mt y-1 based on 50-yr data is comparable to that discharged from Changjaing (500 Mt y-1-decreasing in recent decades, underscoring the importance of sediment budget in the Taiwan Strait and sediment flux from Taiwan into the ECS.We documented fluvial mud and sand concentrations during flash flooding with our observations indicating that fluvial materials in Taiwan¡¦s rivers are chiefly composed of mud (> 70 and up to 98 . By contrast, sand fraction dominates (> 85 for most stations surface sediments in the Taiwan Strait. Super typhoon Herb alone delivered 130 Mt of sediments from Choshui, the largest river in Taiwan, yet only insignificant amounts of mud were found at the river mouth six months later. The actions of waves, tides, and currents apparently prevent the deposition of fine grained sediments. Assuming sand occupied 30 (the maximum of the 60 Mt y-1 total sediment input from major western Taiwanese rivers, our annual budget estimate shows that the amount of sand input (18 5 Mt y-1 is comparable to the burial output of sand (12 10 Mt y-1. However, mud burial (6 5 Mt y-1 in the strait is far below the estimated mud input (42 11 Mt y-1, resulting in a significant shortfall. Hydrodynamic conditions were synthesized to explain the distribution pattern of limited mud patches in the strait and to reveal potential pathways by which fine-grain sediment transportation takes place in the seas surrounding Taiwan. A significant shortfall in the mud budget in the Taiwan Strait suggests that ~85 of the fluvial mud left the strait. Alternatively, the 50-year modern sediment flux data used in this study reflects exacerbated sediment flux due to human

DEVELOPING AN EXCELLENT SEDIMENT RATING CURVE FROM ONE HYDROLOGICAL YEAR SAMPLING PROGRAMME DATA: APPROACH

Directory of Open Access Journals (Sweden)

Preksedis M. Ndomba

2008-01-01

Full Text Available This paper presents preliminary findings on the adequacy of one hydrological year sampling programme data in developing an excellent sediment rating curve. The study case is a 1DD1 subcatchment in the upstream of Pangani River Basin (PRB, located in the North Eastern part of Tanzania. 1DD1 is the major runoff-sediment contributing tributary to the downstream hydropower reservoir, the Nyumba Ya Mungu (NYM. In literature sediment rating curve method is known to underestimate the actual sediment load. In the case of developing countries long-term sediment sampling monitoring or conservation campaigns have been reported as unworkable options. Besides, to the best knowledge of the authors, to date there is no consensus on how to develop an excellent rating curve. Daily-midway and intermittent-cross section sediment samples from Depth Integrating sampler (D-74 were used to calibrate the subdaily automatic sediment pumping sampler (ISCO 6712 near bank point samples for developing the rating curve. Sediment load correction factors were derived from both statistical bias estimators and actual sediment load approaches. It should be noted that the ongoing study is guided by findings of other studies in the same catchment. For instance, long term sediment yield rate estimated based on reservoir survey validated the performance of the developed rating curve. The result suggests that excellent rating curve could be developed from one hydrological year sediment sampling programme data. This study has also found that uncorrected rating curve underestimates sediment load. The degreeof underestimation depends on the type of rating curve developed and data used.

An ecological function and services approach to total maximum daily load (TMDL) prioritization.

Science.gov (United States)

Hall, Robert K; Guiliano, David; Swanson, Sherman; Philbin, Michael J; Lin, John; Aron, Joan L; Schafer, Robin J; Heggem, Daniel T

2014-04-01

Prioritizing total maximum daily load (TMDL) development starts by considering the scope and severity of water pollution and risks to public health and aquatic life. Methodology using quantitative assessments of in-stream water quality is appropriate and effective for point source (PS) dominated discharge, but less so in watersheds with mostly nonpoint source (NPS) related impairments. For NPSs, prioritization in TMDL development and implementation of associated best management practices should focus on restoration of ecosystem physical functions, including how restoration effectiveness depends on design, maintenance and placement within the watershed. To refine the approach to TMDL development, regulators and stakeholders must first ask if the watershed, or ecosystem, is at risk of losing riparian or other ecologically based physical attributes and processes. If so, the next step is an assessment of the spatial arrangement of functionality with a focus on the at-risk areas that could be lost, or could, with some help, regain functions. Evaluating stream and wetland riparian function has advantages over the traditional means of water quality and biological assessments for NPS TMDL development. Understanding how an ecosystem functions enables stakeholders and regulators to determine the severity of problem(s), identify source(s) of impairment, and predict and avoid a decline in water quality. The Upper Reese River, Nevada, provides an example of water quality impairment caused by NPS pollution. In this river basin, stream and wetland riparian proper functioning condition (PFC) protocol, water quality data, and remote sensing imagery were used to identify sediment sources, transport, distribution, and its impact on water quality and aquatic resources. This study found that assessments of ecological function could be used to generate leading (early) indicators of water quality degradation for targeting pollution control measures, while traditional in-stream water

A Regional Survey of River-plume Sedimentation on the Mississippi River Delta Front

Science.gov (United States)

Courtois, A. J.; Bentley, S. J.; Xu, K.; Georgiou, I. Y.; Maloney, J. M.; Miner, M. D.; Chaytor, J. D.; Smith, J.

2017-12-01

Many studies of the Mississippi River and Delta (MRD) have shown historic declines in sediment load reaching the main river distributaries over the last few decades. Recent studies also reported that 50% of the suspended load during floods is sequestered within the delta. While the impact of declining sediment load on wetland loss is well documented, submarine sedimentary processes on the delta front during this recent period of declining sediment load are understudied. To better understand modern sediment dispersal and deposition across the Mississippi River Delta Front, 31 multicores were collected in June 2017 from locations extending offshore from Southwest Pass, South Pass, and Pass a Loutre (the main river outlets) in water depths of 25-280 m. Core locations were selected based on multibeam bathymetry and morphology collected by the USGS in May 2017; the timing of collection coincided with the end of annual peak discharge on the Mississippi River. This multi-agency survey is the first to study delta-front sedimentary processes regionally with such a wide suite of tools. Target locations for coring included the dominant depositional environments: mudflow lobes, gullies, and undisturbed prodelta. Cores were subsampled at 2 cm intervals and analyzed for Beryllium-7 activity via gamma spectrometry; in such settings, Be-7 can be used as a tracer of sediment recently delivered from fluvial origin. Results indicate a general trend of declining Be-7 activity with increasing distance from source, and in deeper water. Inshore samples near Southwest Pass show the deepest penetration depth of Be-7 into the sediment (24-26 cm), which is a preliminary indicator of rapid seasonal sedimentation. Nearshore samples from South Pass exhibited similar Be-7 penetration depths, with results near Pass a Loutre to 14-16 cm depth. Be-7 remains detectable to 2 cm in water 206 m deep, approximately 20 km from South Pass. Sediment dispersal remains impressive offshore from all three

Greywater characterization and loadings - Physicochemical treatment to promote onsite reuse.

Science.gov (United States)

Noutsopoulos, C; Andreadakis, A; Kouris, N; Charchousi, D; Mendrinou, P; Galani, A; Mantziaras, I; Koumaki, E

2018-06-15

Greywater is the wastewater produced in bathtubs, showers, hand basins, kitchen sinks, dishwashers and laundry machines. Segregation of greywater and blackwater and on site greywater treatment in order to promote its reuse for toilet flushing and/or garden irrigation is an interesting option especially in water deficient areas. The objective of this study was to characterize the different greywater sources in Greek households and to evaluate the performance of alternative physicochemical treatment systems to treat several types of greywater. Based on the results average daily greywater production was equal to 98 L per person per day and accounts for approximately 70-75% of the total household wastewater production (135 L per person per day). Among the different sources, laundry and kitchen sink are the main contributors to the total greywater load of organic carbon, suspended solids and surfactants, whereas dishwasher and bathroom greywater are the main sources of phosphorus and endocrine disrupting chemicals respectively. Depending on sources, greywater accounts for as low as 15% of the total wastewater load of organic carbon (in the case of light greywater sources), to as high as 74% of the total load organic load (in the case of the heavy greywater sources). On the other hand, the nutrients load of greywater is limited. The application of a physical treatment system consisting of coagulation, sedimentation, sand filtration, granular activated carbon filtration and disinfection can provide for a final effluent with high quality characteristics for onsite reuse, especially when treating light greywater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Physical and chemical characteristics including total and geochemical forms of phosphorus in sediment from the top 30 centimeters of cores collected in October 2006 at 26 sites in Upper Klamath Lake, Oregon

Science.gov (United States)

Simon, Nancy S.; Ingle, Sarah N.

2011-01-01

μThis study of phosphorus (P) cycling in eutrophic Upper Klamath Lake (UKL), Oregon, was conducted by the U.S. Geological Survey in cooperation with the U.S. Bureau of Reclamation. Lakebed sediments from the upper 30 centimeters (cm) of cores collected from 26 sites were characterized. Cores were sampled at 0.5, 1.5, 2.5, 3.5, 4.5, 10, 15, 20, 25, and 30 cm. Prior to freezing, water content and sediment pH were determined. After being freeze-dried, all samples were separated into greater than 63-micron (μm) particle-size (coarse) and less than 63-μm particle-size (fine) fractions. In the surface samples (0.5 to 4.5 cm below the sediment water interface), approximately three-fourths of the particles were larger than 63-μm. The ratios of the coarse particle-size fraction (>63 μm) and the fine particle-size fraction (determination of total concentrations of aluminum (Al), calcium (Ca), carbon (C), iron (Fe), poorly crystalline Fe, nitrogen (N), P, and titanium (Ti). Total Fe concentrations were the largest in sediment from the northern portion of UKL, Howard Bay, and the southern portion of the lake. Concentrations of total Al, Ca, and Ti were largest in sediment from the northern, central, and southernmost portions of the lake and in sediment from Howard Bay. Concentrations of total C and N were largest in sediment from the embayments and in sediment from the northern arm and southern portion of the lake in the general region of Buck Island. Concentrations of total C were larger in the greater than 63-μm particle-size fraction than in the less than 63-μm particle-size fraction. Sediments were sequentially extracted to determine concentrations of inorganic forms of P, including loosely sorbed P, P associated with poorly crystalline Fe oxides, and P associated with mineral phases. The difference between the concentration of total P and sum of the concentrations of inorganic forms of P is referred to as residual P. Residual P was the largest fraction of P in all

Best Management Practices for sediment control in a Mediterranean agricultural watershed

Science.gov (United States)

Abdelwahab, Ossama M. M.; Bingner, Ronald L.; Milillo, Fabio; Gentile, Francesco

2015-04-01

Soil erosion can lead to severe destruction of agricultural sustainability that affects not only productivity, but the entire ecosystem in the neighboring areas. Sediments transported together with the associated nutrients and chemicals can significantly impact downstream water bodies. Various conservation and management practices implemented individually or integrated together as a system can be used to reduce the negative impacts on agricultural watersheds from soil erosion. Hydrological models are useful tools for decision makers when selecting the most effective combination of management practices to reduce pollutant loads within a watershed system. The Annualized Agricultural Non-point Source (AnnAGNPS) pollutant loading management model can be used to analyze the effectiveness of diverse management and conservation practices that can control or reduce the impact of soil erosion processes and subsequent sediment loads in agricultural watersheds. A 506 km2 Mediterranean medium-size watershed (Carapelle) located in Apulia, Southern Italy was used as a case study to evaluate the model and best management practices (BMPs) for sediment load control. A monitoring station located at the Ordona bridge has been instrumented to continuously monitor stream flow and suspended sediment loads. The station has been equipped with an ultrasound stage meter and a stage recorder to monitor stream flow. An infrared optic probe was used to measure suspended sediment concentrations (Gentile et al., 2010 ). The model was calibrated and validated in the Carapelle watershed on an event basis (Bisantino et al., 2013), and the validated model was used to evaluate the effectiveness of BMPs on sediment reduction. Various management practices were investigated including evaluating the impact on sediment load of: (1) converting all cropland areas into forest and grass covered conditions; (2) converting the highest eroding cropland areas to forest or grass covered conditions; and (3

Lumbriculus variegatus loading study

Data.gov (United States)

U.S. Environmental Protection Agency — Results from sediment bioaccumulation tests with Lumbriculus variegatus with evaluating the effects of organism loading density. This dataset is associated with the...

Estimated suspended-sediment loads and yields in the French and Brandywine Creek Basins, Chester County, Pennsylvania, water years 2008-09

Science.gov (United States)

Sloto, Ronald A.; Olson, Leif E.

2011-01-01

Turbidity and suspended-sediment concentration data were collected by the U.S. Geological Survey (USGS) at four stream stations--French Creek near Phoenixville, West Branch Brandywine Creek near Honey Brook, West Branch Brandywine Creek at Modena, and East Branch Brandywine Creek below Downingtown--in Chester County, Pa. Sedimentation and siltation is the leading cause of stream impairment in Chester County, and these data are critical for quantifying sediment transport. This study was conducted by the USGS in cooperation with the Chester County Water Resources Authority and the Chester County Health Department. Data from optical turbidity sensors deployed at the four stations were recorded at 15- or 30-minute intervals by a data logger and uploaded every 1 to 4 hours to the USGS database. Most of the suspended-sediment samples were collected using automated samplers. The use of optical sensors to continuously monitor turbidity provided an accurate estimate of sediment fluctuations without the collection and analysis costs associated with intensive sampling during storms. Turbidity was used as a surrogate for suspended-sediment concentration (SSC), which is a measure of sedimentation and siltation. Regression models were developed between SSC and turbidity for each of the monitoring stations using SSC data collected from the automated samplers and turbidity data collected at each station. Instantaneous suspended-sediment loads (SSL) were computed from time-series turbidity and discharge data for the 2008 and 2009 water years using the regression equations. The instantaneous computations of SSL were summed to provide daily, storm, and water year annual loads. The annual SSL contributed from each basin was divided by the upstream drainage area to estimate the annual sediment yield. For all four basins, storms provided more than 96 percent of the annual SSL. In each basin, four storms generally provided over half the annual SSL each water year. Stormflows with the

Fourier transform infrared spectroscopy, a new method for rapid determination of total organic and inorganic carbon and biogenic silica concentration in lake sediments

DEFF Research Database (Denmark)

Rosén, Peter; Vogel, Hendrik; Cunningham, Laura

2010-01-01

We demonstrate the use of Fourier transform infrared spectroscopy (FTIRS) to make quantitative measures of total organic carbon (TOC), total inorganic carbon (TIC) and biogenic silica (BSi) concentrations in sediment. FTIRS is a fast and cost-effective technique and only small sediment samples...... varied between r = 0.84-0.99 for TOC, r = 0.85-0.99 for TIC, and r = 0.68-0.94 for BSi. Because FTIR spectra contain information on a large number of both inorganic and organic components, there is great potential for FTIRS to become an important tool in paleolimnology....

Formation and development of a breaker bar under regular waves. Part 2: Sediment transport and morphology

DEFF Research Database (Denmark)

Jacobsen, Niels Gjøl; Fredsøe, Jørgen

2014-01-01

In Part 2 of this work, the hydrodynamic model described in Part 1 is applied for the simulation of sediment transport and the associated morphological development of breaker bars. The sediment description is split into bed load and suspended load, and like the hydrodynamics the sediment transport...

Climate Change Impacts on Sediment Quality of Subalpine Reservoirs: Implications on Management

Directory of Open Access Journals (Sweden)

Marziali Laura

2017-09-01

Full Text Available Reservoirs are characterized by accumulation of sediments where micropollutants may concentrate, with potential toxic effects on downstream river ecosystems. However, sediment management such as flushing is needed to maintain storage capacity. Climate change is expected to increase sediment loads, but potential effects on their quality are scarcely known. In this context, sediment contamination by trace elements (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn and organics (Polycyclic Aromatic Hydrocarbons PAHs, Polychlorinated Biphenyls PCBs and C > 12 hydrocarbons was analyzed in 20 reservoirs located in Italian Central Alps. A strong As and a moderate Cd, Hg and Pb enrichment was emphasized by Igeo, with potential ecotoxicological risk according to Probable Effect Concentration quotients. Sedimentation rate, granulometry, total organic carbon (TOC and altitude resulted as the main drivers governing pollutant concentrations in sediments. According to climate change models, expected increase of rainfall erosivity will enhance soil erosion and consequently the sediment flow to reservoirs, potentially increasing coarse grain fractions and thus potentially diluting pollutants. Conversely, increased weathering may enhance metal fluxes to reservoirs. Increased vegetation cover will potentially result in higher TOC concentrations, which may contrast contaminant bioavailability and thus toxicity. Our results may provide elements for a proper management of contaminated sediments in a climate change scenario aiming at preserving water quality and ecosystem functioning.

Application of 2-D sediment model to fluctuating backwater area of Yangtze River

Directory of Open Access Journals (Sweden)

Yong Fan

2009-09-01

Full Text Available Based on the characteristics of backflow, a two-dimensional mathematical model of sediment movement was established. The complexity of the watercourse boundary at the confluence of the main stream and the tributary was dealt with using a boundary-fitting orthogonal coordinate system. The basic equation of the two-dimensional total sediment load model, the numerical calculation format, and key problems associated with using the orthogonal curvilinear coordinate system were discussed. Water and sediment flow in the Chongqing reach of the Yangtze River were simulated. The calculated water level, flow velocity distribution, amount of silting and scouring, and alluvial distribution are found to be in agreement with the measured data, which indicates that the numerical model and calculation method are reasonable. The model can be used for calculation of flow in a relatively complicated river network.

Sediment transport to and from small impoundments in northeast Kansas, March 2009 through September 2011

Science.gov (United States)

Foster, Guy M.; Lee, Casey J.; Ziegler, Andrew C.

2012-01-01

The U.S. Geological Survey, in cooperation with the Kansas Water Office, investigated sediment transport to and from three small impoundments (average surface area of 0.1 to 0.8 square miles) in northeast Kansas during March 2009 through September 2011. Streamgages and continuous turbidity sensors were operated upstream and downstream from Atchison County, Banner Creek, and Centralia Lakes to study the effect of varied watershed characteristics and agricultural practices on sediment transport in small watersheds in northeast Kansas. Atchison County Lake is located in a predominantly agricultural basin of row crops, with wide riparian buffers along streams, a substantial amount of tile drainage, and numerous small impoundments (less than 0.05 square miles; hereafter referred to as “ponds”). Banner Creek Lake is a predominantly grassland basin with numerous small ponds located in the watershed, and wide riparian buffers along streams. Centralia Lake is a predominantly agricultural basin of row crops with few ponds, few riparian buffers along streams, and minimal tile drainage. Upstream from Atchison County, Banner Creek, and Centralia Lakes 24, 38, and 32 percent, respectively, of the total load was transported during less than 0.1 percent (approximately 0.9 days) of the time. Despite less streamflow in 2011, larger sediment loads during that year indicate that not all storm events transport the same amount of sediment; larger, extreme storms during the spring may transport much larger sediment loads in small Kansas watersheds. Annual sediment yields were 360, 400, and 970 tons per square mile per year at Atchison County, Banner, and Centralia Lake watersheds, respectively, which were less than estimated yields for this area of Kansas (between 2,000 and 5,000 tons per square mile per year). Although Centralia and Atchison County Lakes had similar percentages of agricultural land use, mean annual sediment yields upstream from Centralia Lake were about 2.7 times

LOADING SIMULATION PROGRAM C

Science.gov (United States)

LSPC is the Loading Simulation Program in C++, a watershed modeling system that includes streamlined Hydrologic Simulation Program Fortran (HSPF) algorithms for simulating hydrology, sediment, and general water quality

Sediment phosphorus speciation and mobility under dynamic redox conditions

Science.gov (United States)

Parsons, Chris T.; Rezanezhad, Fereidoun; O'Connell, David W.; Van Cappellen, Philippe

2017-07-01

Anthropogenic nutrient enrichment has caused phosphorus (P) accumulation in many freshwater sediments, raising concerns that internal loading from legacy P may delay the recovery of aquatic ecosystems suffering from eutrophication. Benthic recycling of P strongly depends on the redox regime within surficial sediment. In many shallow environments, redox conditions tend to be highly dynamic as a result of, among others, bioturbation by macrofauna, root activity, sediment resuspension and seasonal variations in bottom-water oxygen (O2) concentrations. To gain insight into the mobility and biogeochemistry of P under fluctuating redox conditions, a suspension of sediment from a hypereutrophic freshwater marsh was exposed to alternating 7-day periods of purging with air and nitrogen gas (N2), for a total duration of 74 days, in a bioreactor system. We present comprehensive data time series of bulk aqueous- and solid-phase chemistry, solid-phase phosphorus speciation and hydrolytic enzyme activities demonstrating the mass balanced redistribution of P in sediment during redox cycling. Aqueous phosphate concentrations remained low ( ˜ 2.5 µM) under oxic conditions due to sorption to iron(III) oxyhydroxides. During anoxic periods, once nitrate was depleted, the reductive dissolution of iron(III) oxyhydroxides released P. However, only 4.5 % of the released P accumulated in solution while the rest was redistributed between the MgCl2 and NaHCO3 extractable fractions of the solid phase. Thus, under the short redox fluctuations imposed in the experiments, P remobilization to the aqueous phase remained relatively limited. Orthophosphate predominated at all times during the experiment in both the solid and aqueous phase. Combined P monoesters and diesters accounted for between 9 and 16 % of sediment particulate P. Phosphatase activities up to 2.4 mmol h-1 kg-1 indicated the potential for rapid mineralization of organic P (Po), in particular during periods of aeration when the

Response of a macrotidal estuary to changes in anthropogenic mercury loading between 1850 and 2000.

Science.gov (United States)

Sunderland, Elsie M; Dalziel, John; Heyes, Andrew; Branfireun, Brian A; Krabbenhoft, David P; Gobas, Frank A P C

2010-03-01

Methylmercury (MeHg) bioaccumulation in marine food webs poses risks to fish-consuming populations and wildlife. Here we develop and test an estuarine mercury cycling model for a coastal embayment of the Bay of Fundy, Canada. Mass budget calculations reveal that MeHg fluxes into sediments from settling solids exceed losses from sediment-to-water diffusion and resuspension. Although measured methylation rates in benthic sediments are high, rapid demethylation results in negligible net in situ production of MeHg. These results suggest that inflowing fluvial and tidal waters, rather than coastal sediments, are the dominant MeHg sources for pelagic marine food webs in this region. Model simulations show water column MeHg concentrations peaked in the 1960s and declined by almost 40% by the year 2000. Water column MeHg concentrations respond rapidly to changes in mercury inputs, reaching 95% of steady state in approximately 2 months. Thus, MeHg concentrations in pelagic organisms can be expected to respond rapidly to mercury loading reductions achieved through regulatory controls. In contrast, MeHg concentrations in sediments have steadily increased since the onset of industrialization despite recent decreases in total mercury loading. Benthic food web MeHg concentrations are likely to continue to increase over the next several decades at present-day mercury emissions levels because the deep active sediment layer in this system contains a large amount of legacy mercury and requires hundreds of years to reach steady state with inputs.

SALMONELLA SPECIE AND TOTAL VIABLE BACTERIAL LOAD IN ROASTED CHICKENS SOLD IN JOS-NIGERIA

OpenAIRE

Carol Okoli; Okonji M.C; Ugoh S.C; Okolo S.N; Okoli A.C; Alu A.J

2007-01-01

The study was to investigate for the presence of Salmonella specie and total viable aerobic bacterial load in roasted chickens sold in Jos. The study was carried out on twenty five chicken samples. No salmonella specie was isolated from the samples. However, other bacterial organisms were isolates, viz: 9(36%) of the samples yielded E.coli; 5(20%) yielded Citobacter species; 3(12%) yielded Proteus species and 6(24%) yielded Klebsiella species while 2(8%) showed no growth. An average total via...

Estimation of Ravine Sediment production using MIKE 11 model, in the lower Le Sueur Watershed, Minnesota

Science.gov (United States)

Azmera, L. A.; Miralles-Wilhelm, F. R.; Melesse, A. M.; Belmont, P.; Jennings, C. E.; Thomas, A.; Khalif, F.

2008-12-01

A study of sediment dynamics in the Le Sueur River basin, southern Minnesota has been initiated with the goal of developing an integrated sediment budget. Preliminary analysis of the sediment load to the Minnesota River has shown that the Le Sueur River contributes substantial amount of the sediment transport and deposition. Many deeply incised ravines exist, especially towards the lower Le Sueur River. The ravines are believed to be one of the major sediment producing sources in the river basin. Hence the ravine sediment production should be accounted for in the sediment budget. This study concentrates on the hydrology of the ravines and evaluates the sediment budget at the ravine scale. Field observations from summer 2008 show that most of the bluffs along the main stem of both ravines are actively eroding. Also, landsliding of the steep ravine valley walls and rapid incision of the fluvial channels within the ravine are producing sediment. Several large fill terraces are present along the main stem, towards the mouth of the ravines. Recent incision through these extensive fill terraces may be another sediment producing source. Sediment storage in the ravines also occurs, behind woody debris jams as well as in locations where local baselevel has been raised by the insertion of a culvert. The sediment budget of the ravines would be quantified as the difference between the storage of sediment and the sum of sediments loads derived from the uplands, as well as the bluffs and terraces inside the ravines. Primary locations of major bluffs, terraces, gullies and drainage tiles in the gauged ravines were mapped using GPS. A database of major bluff, terraces, and drainage tiles was built in ArcGIS. Sediment samples from ravine heads, bluffs, terraces and ravine mouth were collected to study the grain size distribution and stratigraphy of major bluffs along the ravines. Sediment transport in the ravines will be modeled using MIKE 11 (DHI group), a dynamic, one

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

Science.gov (United States)

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.

Application of Long Distance Conveyance (LDC) of Dredged Sediments to Louisiana Coastal Restoration

Science.gov (United States)

2011-01-01

generally use some type of bucket for digging the sediment, then hoist or boom the load to the surface. Most common hydraulic methods use a centrifugal...sediment. The loaded bucket is hoisted to the surface and side dumped into a transportation unit, or into the disposal site. Transportation units are...Conveyance (LDC) of Dredged Sediments to Louisiana Coastal Restoration Timothy Welp Coastal and Hydraulics Laboratory U.S. Army Engineer Research

Total and species-specific quantitative analyses of trace elements in sediment by isotope dilution inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Inagaki, Kazumi; Takatsu, Akiko; Yarita, Takashi; Okamoto, Kensaku; Chiba, Koichi

2009-01-01

Isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) is one of the reliable methods for total and species-specific quantitative analysis of trace elements. However, several technical problems (e.g. spectral interference caused from sample constituents) should be overcome to obtain reliable analytical results when environmental samples are analyzed by ID-ICP-MS. In our laboratory, various methods based on ID-ICP-MS have been investigated for reliable quantitative analyses of trace elements in environmental samples. In this paper, coprecipitate separation/ID-ICP-MS for the determination of trace elements in sediment, cation exchange disk filtration/ID-ICP-MS for the determination of selenium in sediment, species-specific ID-ICP-MS using 118 Sn/labeled organotin compounds for the determination of butyltins and phenyltins, and the application of the ID-ICP-MS methods to the certification of sediment reference materials are described. (author)

A computational parametric study on edge loading in ceramic-on-ceramic total hip joint replacements.

Science.gov (United States)

Liu, Feng; Feng, Li; Wang, Junyuan

2018-07-01

Edge loading in ceramic-on-ceramic total hip joint replacement is an adverse condition that occurs as the result of a direct contact between the head and the cup rim. It has been associated with translational mismatch in the centres of rotation of the cup and head, and found to cause severe wear and early failure of the implants. Edge loading has been considered in particular in relation to dynamic separation of the cup and head centres during a gait cycle. Research has been carried out both experimentally and computationally to understand the mechanism including the influence of bearing component positioning on the occurrence and severity of edge loading. However, it is experimentally difficult to measure both the load magnitude and duration of edge loading as it occurs as a short impact within the tight space of hip joints. Computationally, a dynamic contact model, for example, developed using the MSC ADAMS software for a multi-body dynamics simulation can be particularly useful for calculating the loads and characterising the edge loading. The aim of the present study was to further develop the computational model, and improve the predictions of contact force and the understanding of mechanism in order to provide guidance on design and surgical factors to avoid or to reduce edge loading and wear. The results have shown that edge loading can be avoided for a low range of translational mismatch in the centres of rotation of the cup and head during gait at the level of approximately 1.0 mm for a cup at 45° inclination, keeping a correct cup inclination at 45° is important to reduce the edge loading severity, and edge loading can be avoided for a certain range of translational mismatch of the cup and head centres with an increased swing phase load. Copyright © 2018 Elsevier Ltd. All rights reserved.

Spatial and temporal variations of loads and sources of total and dissolved Phosphorus in a set of rivers (Western France).

Science.gov (United States)

Legeay, Pierre-Louis; Moatar, Florentina; Gascuel-Odoux, Chantal; Gruau, Gérard

2015-04-01

In intensive agricultural regions with important livestock farming, long-term land application of Phosphorus (P) both as chemical fertilizer and animal wastes, have resulted in elevated P contents in soils. Since we know that high P concentrations in rivers is of major concern, few studies have been done at to assess the spatiotemporal variability of P loads in rivers and apportionment of point and nonpoint source in total loads. Here we focus on Brittany (Western France) where even though P is a great issue in terms of human and drinking water safety (cyano-toxins), environmental protection and economic costs for Brittany with regards to the periodic proliferations of cyanobacteria that occur every year in this region, no regional-scale systematic study has been carried out so far. We selected a set of small rivers (stream order 3-5) with homogeneous agriculture and granitic catchment. By gathering data from three water quality monitoring networks, covering more than 100 measurements stations, we provide a regional-scale quantification of the spatiotemporal variability of dissolved P (DP) and total P (TP) interannual loads from 1992 to 2012. Build on mean P load in low flows and statistical significance tests, we developed a new indicator, called 'low flow P load' (LFP-load), which allows us to determine the importance of domestic and industrial P sources in total P load and to assess their spatiotemporal variability compared to agricultural sources. The calculation and the map representation of DP and TP interannual load variations allow identification of the greatest and lowest P contributory catchments over the study period and the way P loads of Brittany rivers have evolved through time. Both mean DP and TP loads have been divided by more than two over the last 20 years. Mean LFDP-load decreased by more than 60% and mean LFTP-load by more than 45% on average over the same period showing that this marked temporal decrease in total load is largely due to the

Significance of flow clustering and sequencing on sediment transport: 1D sediment transport modelling

Science.gov (United States)

Hassan, Kazi; Allen, Deonie; Haynes, Heather

2016-04-01

This paper considers 1D hydraulic model data on the effect of high flow clusters and sequencing on sediment transport. Using observed flow gauge data from the River Caldew, England, a novel stochastic modelling approach was developed in order to create alternative 50 year flow sequences. Whilst the observed probability density of gauge data was preserved in all sequences, the order in which those flows occurred was varied using the output from a Hidden Markov Model (HMM) with generalised Pareto distribution (GP). In total, one hundred 50 year synthetic flow series were generated and used as the inflow boundary conditions for individual flow series model runs using the 1D sediment transport model HEC-RAS. The model routed graded sediment through the case study river reach to define the long-term morphological changes. Comparison of individual simulations provided a detailed understanding of the sensitivity of channel capacity to flow sequence. Specifically, each 50 year synthetic flow sequence was analysed using a 3-month, 6-month or 12-month rolling window approach and classified for clusters in peak discharge. As a cluster is described as a temporal grouping of flow events above a specified threshold, the threshold condition used herein is considered as a morphologically active channel forming discharge event. Thus, clusters were identified for peak discharges in excess of 10%, 20%, 50%, 100% and 150% of the 1 year Return Period (RP) event. The window of above-peak flows also required cluster definition and was tested for timeframes 1, 2, 10 and 30 days. Subsequently, clusters could be described in terms of the number of events, maximum peak flow discharge, cumulative flow discharge and skewness (i.e. a description of the flow sequence). The model output for each cluster was analysed for the cumulative flow volume and cumulative sediment transport (mass). This was then compared to the total sediment transport of a single flow event of equivalent flow volume

A doubling of microphytobenthos biomass coincides with a tenfold increase in denitrifier and total bacterial abundances in intertidal sediments of a temperate estuary.

Directory of Open Access Journals (Sweden)

Helen Decleyre

Full Text Available Surface sediments are important systems for the removal of anthropogenically derived inorganic nitrogen in estuaries. They are often characterized by the presence of a microphytobenthos (MPB biofilm, which can impact bacterial communities in underlying sediments for example by secretion of extracellular polymeric substances (EPS and competition for nutrients (including nitrogen. Pyrosequencing and qPCR was performed on two intertidal surface sediments of the Westerschelde estuary characterized by a two-fold difference in MPB biomass but no difference in MPB composition. Doubling of MPB biomass was accompanied by a disproportionately (ten-fold increase in total bacterial abundances while, unexpectedly, no difference in general community structure was observed, despite significantly lower bacterial richness and distinct community membership, mostly for non-abundant taxa. Denitrifier abundances corresponded likewise while community structure, both for nirS and nirK denitrifiers, remained unchanged, suggesting that competition with diatoms for nitrate is negligible at concentrations in the investigated sediments (appr. 1 mg/l NO3-. This study indicates that MPB biomass increase has a general, significantly positive effect on total bacterial and denitrifier abundances, with stimulation or inhibition of specific bacterial groups that however do not result in a re-structured community.

Mixture design and treatment methods for recycling contaminated sediment

International Nuclear Information System (INIS)

Wang, Lei; Kwok, June S.H.; Tsang, Daniel C.W.; Poon, Chi-Sun

2015-01-01

Graphical abstract: - Highlights: • Contaminated sediment can be recycled as fill material for site formation. • Thermal pretreatment of sediment permits non-load-bearing block application. • CO 2 curing enhances strength and reduces carbon footprint. • Inclusion of granular wastes reinforces the solidified sediment matrix. • Sediment blocks are useful resources for construction use. - Abstract: Conventional marine disposal of contaminated sediment presents significant financial and environmental burden. This study aimed to recycle the contaminated sediment by assessing the roles and integration of binder formulation, sediment pretreatment, curing method, and waste inclusion in stabilization/solidification. The results demonstrated that the 28-d compressive strength of sediment blocks produced with coal fly ash and lime partially replacing cement at a binder-to-sediment ratio of 3:7 could be used as fill materials for construction. The X-ray diffraction analysis revealed that hydration products (calcium hydroxide) were difficult to form at high sediment content. Thermal pretreatment of sediment removed 90% of indigenous organic matter, significantly increased the compressive strength, and enabled reuse as non-load-bearing masonry units. Besides, 2-h CO 2 curing accelerated early-stage carbonation inside the porous structure, sequestered 5.6% of CO 2 (by weight) in the sediment blocks, and acquired strength comparable to 7-d curing. Thermogravimetric analysis indicated substantial weight loss corresponding to decomposition of poorly and well crystalline calcium carbonate. Moreover, partial replacement of contaminated sediment by various granular waste materials notably augmented the strength of sediment blocks. The metal leachability of sediment blocks was minimal and acceptable for reuse. These results suggest that contaminated sediment should be viewed as useful resources

Mixture design and treatment methods for recycling contaminated sediment

Energy Technology Data Exchange (ETDEWEB)

Wang, Lei; Kwok, June S.H.; Tsang, Daniel C.W., E-mail: dan.tsang@polyu.edu.hk; Poon, Chi-Sun

2015-02-11

Graphical abstract: - Highlights: • Contaminated sediment can be recycled as fill material for site formation. • Thermal pretreatment of sediment permits non-load-bearing block application. • CO{sub 2} curing enhances strength and reduces carbon footprint. • Inclusion of granular wastes reinforces the solidified sediment matrix. • Sediment blocks are useful resources for construction use. - Abstract: Conventional marine disposal of contaminated sediment presents significant financial and environmental burden. This study aimed to recycle the contaminated sediment by assessing the roles and integration of binder formulation, sediment pretreatment, curing method, and waste inclusion in stabilization/solidification. The results demonstrated that the 28-d compressive strength of sediment blocks produced with coal fly ash and lime partially replacing cement at a binder-to-sediment ratio of 3:7 could be used as fill materials for construction. The X-ray diffraction analysis revealed that hydration products (calcium hydroxide) were difficult to form at high sediment content. Thermal pretreatment of sediment removed 90% of indigenous organic matter, significantly increased the compressive strength, and enabled reuse as non-load-bearing masonry units. Besides, 2-h CO{sub 2} curing accelerated early-stage carbonation inside the porous structure, sequestered 5.6% of CO{sub 2} (by weight) in the sediment blocks, and acquired strength comparable to 7-d curing. Thermogravimetric analysis indicated substantial weight loss corresponding to decomposition of poorly and well crystalline calcium carbonate. Moreover, partial replacement of contaminated sediment by various granular waste materials notably augmented the strength of sediment blocks. The metal leachability of sediment blocks was minimal and acceptable for reuse. These results suggest that contaminated sediment should be viewed as useful resources.

Leaching tendencies of uranium and regulated trace metals from the Hanford Site 300 Area North Process Pond sediments

International Nuclear Information System (INIS)

Serne, R.J.; LeGore, V.L.; Mattigod, S.V.

1994-09-01

Data are presented that address the leaching tendencies and the total chemical composition of metals in feed materials and soil-washed fines generated by Alternative Remediation Technology, Inc. during a pilot-scale soil physical separation test performed at the 300 Area North Process Pond (Facility 316-2) on the Hanford Site in the spring of 1994. Four 300 Area North Process Pond sediments and one sediment from outside the pond's fenced area were leach-tested using the Toxicity Characteristic Leach Procedure (TCLP) and other modified US Environmental Protection Agency and American Society for Testing and Materials protocols. Finally, leachate from the most contaminated sediment was used to load the Hanford sediment obtained outside the facility to evaluate the potential for contaminant adsorption onto natural sediments. The sediment characterization, leach, and adsorption results will be used in the evaluation of remedial alternatives in the 300-FF-1 Operable Unit Remedial Investigation/Feasibility Study

Sediment contributions from floodplains and legacy sediments to Piedmont streams of Baltimore County, Maryland

Science.gov (United States)

Donovan, Mitchell; Miller, Andrew; Baker, Matthew; Gellis, Allen C.

2015-01-01

Disparity between watershed erosion rates and downstream sediment delivery has remained an important theme in geomorphology for many decades, with the role of floodplains in sediment storage as a common focus. In the Piedmont Province of the eastern USA, upland deforestation and agricultural land use following European settlement led to accumulation of thick packages of overbank sediment in valley bottoms, commonly referred to as legacy deposits. Previous authors have argued that legacy deposits represent a potentially important source of modern sediment loads following remobilization by lateral migration and progressive channel widening. This paper seeks to quantify (1) rates of sediment remobilization from Baltimore County floodplains by channel migration and bank erosion, (2) proportions of streambank sediment derived from legacy deposits, and (3) potential contribution of net streambank erosion and legacy sediments to downstream sediment yield within the Mid-Atlantic Piedmont.We calculated measurable gross erosion and deposition rates within the fluvial corridor along 40 valley segments from 18 watersheds with drainage areas between 0.18 and 155 km2 in Baltimore County, Maryland. We compared stream channel and floodplain morphology from lidar-based digital elevation data collected in 2005 with channel positions recorded on 1:2400 scale topographic maps from 1959–1961 in order to quantify 44–46 years of channel change. Sediment bulk density and particle size distributions were characterized from streambank and channel deposit samples and used for volume to mass conversions and for comparison with other sediment sources.Average annual lateral migration rates ranged from 0.04 to 0.19 m/y, which represented an annual migration of 2.5% (0.9–4.4%) channel width across all study segments, suggesting that channel dimensions may be used as reasonable predictors of bank erosion rates. Gross bank erosion rates varied from 43 to 310 Mg/km/y (median = 114) and

Ephemeral seafloor sedimentation during dam removal: Elwha River, Washington

Science.gov (United States)

Foley, Melissa M.; Warrick, Jonathan

2017-01-01

The removal of the Elwha and Glines Canyon dams from the Elwha River in Washington, USA, resulted in the erosion and transport of over 10 million m3 of sediment from the former reservoirs and into the river during the first two years of the dam removal process. Approximately 90% of this sediment was transported through the Elwha River and to the coast at the Strait of Juan de Fuca. To evaluate the benthic dynamics of increased sediment loading to the nearshore, we deployed a tripod system in ten meters of water to the east of the Elwha River mouth that included a profiling current meter and a camera system. With these data, we were able to document the frequency and duration of sedimentation and turbidity events, and correlate these events to physical oceanographic and river conditions. We found that seafloor sedimentation occurred regularly during the heaviest sediment loading from the river, but that this sedimentation was ephemeral and exhibited regular cycles of deposition and erosion caused by the strong tidal currents in the region. Understanding the frequency and duration of short-term sediment disturbance events is instrumental to interpreting the ecosystem-wide changes that are occurring in the nearshore habitats around the Elwha River delta.

Ephemeral seafloor sedimentation during dam removal: Elwha River, Washington

Science.gov (United States)

Foley, Melissa M.; Warrick, Jonathan A.

2017-11-01

The removal of the Elwha and Glines Canyon dams from the Elwha River in Washington, USA, resulted in the erosion and transport of over 10 million m3 of sediment from the former reservoirs and into the river during the first two years of the dam removal process. Approximately 90% of this sediment was transported through the Elwha River and to the coast at the Strait of Juan de Fuca. To evaluate the benthic dynamics of increased sediment loading to the nearshore, we deployed a tripod system in ten meters of water to the east of the Elwha River mouth that included a profiling current meter and a camera system. With these data, we were able to document the frequency and duration of sedimentation and turbidity events, and correlate these events to physical oceanographic and river conditions. We found that seafloor sedimentation occurred regularly during the heaviest sediment loading from the river, but that this sedimentation was ephemeral and exhibited regular cycles of deposition and erosion caused by the strong tidal currents in the region. Understanding the frequency and duration of short-term sediment disturbance events is instrumental to interpreting the ecosystem-wide changes that are occurring in the nearshore habitats around the Elwha River delta.

Relation of nutrient concentrations, nutrient loading, and algal production to changes in water levels in Kabetogama Lake, Voyageurs National Park, northern Minnesota, 2008-09

Science.gov (United States)

Christensen, Victoria G.; Maki, Ryan P.; Kiesling, Richard L.

2011-01-01

Nutrient enrichment has led to excessive algal growth in Kabetogama Lake, Voyageurs National Park, northern Minnesota. Water- and sediment-quality data were collected during 2008-09 to assess internal and external nutrient loading. Data collection was focused in Kabetogama Lake and its inflows, the area of greatest concern for eutrophication among the lakes of Voyageurs National Park. Nutrient and algal data were used to determine trophic status and were evaluated in relation to changes in Kabetogama Lake water levels following changes to dam operation starting in 2000. Analyses were used to estimate external nutrient loading at inflows and assess the potential contribution of internal phosphorus loading. Kabetogama Lake often was mixed vertically, except for a few occasionally stratified areas, including Lost Bay in the northeastern part of Kabetogama Lake. Stratification, combined with larger bottom-water nutrient concentrations, larger sediment phosphorus concentrations, and estimated phosphorus release rates from sediment cores indicate that Lost Bay may be one of several areas that may be contributing substantially to internal loading. Internal loading is a concern because nutrients may cause excessive algal growth including potentially toxic cyanobacteria. The cyanobacterial hepatotoxin, microcystin, was detected in 7 of 14 cyanobacterial bloom samples, with total concentrations exceeding 1.0 microgram per liter, the World Health Organization's guideline for finished drinking water for the congener, microcystin-LR. Comparisons of the results of this study to previous studies indicate that chlorophyll-a concentrations and trophic state indices have improved since 2000, when the rules governing dam operation changed. However, total-phosphorus concentrations have not changed significantly since 2000.

Sediment budget for a polluted Hawaiian reef using hillslope monitoring and process mapping (Invited)

Science.gov (United States)

Stock, J. D.; Rosener, M.; Schmidt, K. M.; Hanshaw, M. N.; Brooks, B. A.; Tribble, G.; Jacobi, J.

2010-12-01

Pollution from coastal watersheds threatens the ecology of the nearshore, including tropical reefs. Suspended sediment concentrations off the reefs of Molokai, Hawaii, chronically exceed a toxic 10 mg/L, threatening reef ecosystems. We hypothesize that historic conversion of hillslope processes from soil creep to overland flow increased both magnitude and frequency of erosion. To create a process sediment budget, we used surficial and ecological mapping, hillslope and stream gages, and novel sensors to locate, quantify and model the generation of fine sediments polluting the reef. Ecological and geomorphic mapping from LiDAR and multi-spectral imagery located overland flow areas with vegetation cover below a threshold preventing erosion. Here, feral goat grazing exposed volcanic soils whose low matrix hydraulic conductivities (1-25 mm/hour) promote Horton overland flow. We instrumented steep, barren hillslopes with soil moisture sensors, overland flow meters, Parshal flumes, ISCO sediment samplers, and a rain gage and conducted repeat Tripod LiDAR and infiltration tests. To characterize soil resistance to overland flow erosion, we used a Cohesive Strength Meter (CSM) to simulate water stress. At the 13.5 km 2 watershed mouth we used a USGS stream gage with an ISCO sediment sampler to estimate total load. Over 3 years, storms triggered overland flow during rainfall intensities above 10-15 mm/hr. Overland flow meters indicate such flows can be up to 3 cm deep, with a tendency to deepen downslope. CSM tests indicate that these depths are insufficient to erode soils where vegetation is dense, but far above threshold values of 2-3 mm for bare soils. Sediment ratings curves for both hillslope and downstream catchment gages show clock-wise hysteresis during the first intense storms in the fall, becoming linear later in the season. During fall storms, sediment concentration is often 10X higher at a given stage. Revised annual lowering rates from experimental hillslopes are

Decadal-scale export of nitrogen, phosphorus, and sediment from the Susquehanna River basin, USA: Analysis and synthesis of temporal and spatial patterns.

Science.gov (United States)

Zhang, Qian; Ball, William P; Moyer, Douglas L

2016-09-01

The export of nitrogen (N), phosphorus (P), and suspended sediment (SS) is a long-standing management concern for the Chesapeake Bay watershed, USA. Here we present a comprehensive evaluation of nutrient and sediment loads over the last three decades at multiple locations in the Susquehanna River basin (SRB), Chesapeake's largest tributary watershed. Sediment and nutrient riverine loadings, including both dissolved and particulate fractions, have generally declined at all sites upstream of Conowingo Dam (non-tidal SRB outlet). Period-of-record declines in riverine yield are generally smaller than those in source input, suggesting the possibility of legacy contributions. Consistent with other watershed studies, these results reinforce the importance of considering lag time between the implementation of management actions and achievement of river quality improvement. Whereas flow-normalized loadings for particulate species have increased recently below Conowingo Reservoir, those for upstream sites have declined, thus substantiating conclusions from prior studies about decreased reservoir trapping efficiency. In regard to streamflow effects, statistically significant log-linear relationships between annual streamflow and annual constituent load suggest the dominance of hydrological control on the inter-annual variability of constituent export. Concentration-discharge relationships revealed general chemostasis and mobilization effects for dissolved and particulate species, respectively, both suggesting transport-limitation conditions. In addition to affecting annual export rates, streamflow has also modulated the relative importance of dissolved and particulate fractions, as reflected by its negative correlations with dissolved P/total P, dissolved N/total N, particulate P/SS, and total N/total P ratios. For land-use effects, period-of-record median annual yields of N, P, and SS all correlate positively with the area fraction of non-forested land but negatively with

Decadal-scale export of nitrogen, phosphorus, and sediment from the Susquehanna River basin, USA: Analysis and synthesis of temporal and spatial patterns

Science.gov (United States)

Zhang, Qian; Ball, William P.; Moyer, Douglas

2016-01-01

The export of nitrogen (N), phosphorus (P), and suspended sediment (SS) is a long-standing management concern for the Chesapeake Bay watershed, USA. Here we present a comprehensive evaluation of nutrient and sediment loads over the last three decades at multiple locations in the Susquehanna River basin (SRB), Chesapeake's largest tributary watershed. Sediment and nutrient riverine loadings, including both dissolved and particulate fractions, have generally declined at all sites upstream of Conowingo Dam (non-tidal SRB outlet). Period-of-record declines in riverine yield are generally smaller than those in source input, suggesting the possibility of legacy contributions. Consistent with other watershed studies, these results reinforce the importance of considering lag time between the implementation of management actions and achievement of river quality improvement. Whereas flow-normalized loadings for particulate species have increased recently below Conowingo Reservoir, those for upstream sites have declined, thus substantiating conclusions from prior studies about decreased reservoir trapping efficiency. In regard to streamflow effects, statistically significant log-linear relationships between annual streamflow and annual constituent load suggest the dominance of hydrological control on the inter-annual variability of constituent export. Concentration-discharge relationships revealed general chemostasis and mobilization effects for dissolved and particulate species, respectively, both suggesting transport-limitation conditions. In addition to affecting annual export rates, streamflow has also modulated the relative importance of dissolved and particulate fractions, as reflected by its negative correlations with dissolved P/total P, dissolved N/total N, particulate P/SS, and total N/total P ratios. For land-use effects, period-of-record median annual yields of N, P, and SS all correlate positively with the area fraction of non-forested land but negatively with

Thermally induced motion of marine sediments resulting from disposal of radioactive wastes

International Nuclear Information System (INIS)

Chavez, P.F.; Dawson, P.R.

1981-01-01

Coupled creep and heat transfer calculations have been performed to assess the sensitivity of heat load, viscosity, and canister density on the motion of waste canisters buried in marine sediments. Results indicate that no upward movement is predicted for heat loads remaining within the metallurgical and geochemical constraints placed on the temperature of sediments near the canister for the times analyzed. Upward movement of the canister is again not observed in calculations involving reasonable variations of the sediment viscosity and canister density. Maximum effective deviatoric stress levels due to thermally induced differential body forces are significantly less than the sediment's short term peak strength

The release of dissolved phosphorus from lake sediments

NARCIS (Netherlands)

Boers, P.C.M.

1991-01-01

Chapter 1. Introduction: Eutrophication is one of the world's major water quality problems. Attempts to alleviate eutrophication of lakes have involved the control of phosphorus loadings. In such cases, an internal loading of phosphorus from the sediments may

Estimates of Radionuclide Loading to Cochiti Lake from Los Alamos Canyon Using Manual and Automated Sampling

Energy Technology Data Exchange (ETDEWEB)

McLean, Christopher T. [Univ. of New Mexico, Albuquerque, NM (United States)

2000-07-01

Los Alamos National Laboratory has a long-standing program of sampling storm water runoff inside the Laboratory boundaries. In 1995, the Laboratory started collecting the samples using automated storm water sampling stations; prior to this time the samples were collected manually. The Laboratory has also been periodically collecting sediment samples from Cochiti Lake. This paper presents the data for Pu-238 and Pu-239 bound to the sediments for Los Alamos Canyon storm water runoff and compares the sampling types by mass loading and as a percentage of the sediment deposition to Cochiti Lake. The data for both manual and automated sampling are used to calculate mass loads from Los Alamos Canyon on a yearly basis. The automated samples show mass loading 200- 500 percent greater for Pu-238 and 300-700 percent greater for Pu-239 than the manual samples. Using the mean manual flow volume for mass loading calculations, the automated samples are over 900 percent greater for Pu-238 and over 1800 percent greater for Pu-239. Evaluating the Pu-238 and Pu-239 activities as a percentage of deposition to Cochiti Lake indicates that the automated samples are 700-1300 percent greater for Pu- 238 and 200-500 percent greater for Pu-239. The variance was calculated by two methods. The first method calculates the variance for each sample event. The second method calculates the variances by the total volume of water discharged in Los Alamos Canyon for the year.

Pesticide load dynamics during stormwater flow events in Mediterranean coastal streams: Alexander stream case study.

Science.gov (United States)

Topaz, Tom; Egozi, Roey; Eshel, Gil; Chefetz, Benny

2018-06-01

Cultivated land is a major source of pesticides, which are transported with the runoff water and eroded soil during rainfall events and pollute riverine and estuarine environments. Common ecotoxicological assessments of riverine systems are mainly based on water sampling and analysis of only the dissolved phase, and address a single pesticide's toxicological impact under laboratory conditions. A clear overview of mixtures of pesticides in the adsorbed and dissolved phases is missing, and therefore the full ecotoxicological impact is not fully addressed. The aim of this study was to characterize and quantify pesticide concentrations in both suspended sediment and dissolved phases, to provide a better understanding of pesticide-load dynamics during storm events in coastal streams in a Mediterranean climate. High-resolution sampling campaigns of seven flood events were conducted during two rainy seasons in Alexander stream, Israel. Samples of suspended sediments were separated from the solution and both media were analyzed separately for 250 pesticides. A total of 63 pesticides were detected; 18 and 16 pesticides were found solely in the suspended sediments and solution, respectively. Significant differences were observed among the pesticide groups: only 7% of herbicide, 20% of fungicide and 42% of insecticide load was transported with the suspended sediments. However, in both dissolved and adsorbed phases, a mix of pesticides was found which were graded from "mobile" to "non-mobile" with varied distribution coefficients. Diuron, and tebuconazole were frequently found in large quantities in both phases. Whereas insecticide and fungicide transport is likely governed by application time and method, the governing factor for herbicide load was the magnitude of the stream discharge. The results show a complex dynamic of pesticide load affected by excessive use of pesticides, which should be taken into consideration when designing projects to monitor riverine and estuarine

Harmonize input selection for sediment transport prediction

Science.gov (United States)

Afan, Haitham Abdulmohsin; Keshtegar, Behrooz; Mohtar, Wan Hanna Melini Wan; El-Shafie, Ahmed

2017-09-01

In this paper, three modeling approaches using a Neural Network (NN), Response Surface Method (RSM) and response surface method basis Global Harmony Search (GHS) are applied to predict the daily time series suspended sediment load. Generally, the input variables for forecasting the suspended sediment load are manually selected based on the maximum correlations of input variables in the modeling approaches based on NN and RSM. The RSM is improved to select the input variables by using the errors terms of training data based on the GHS, namely as response surface method and global harmony search (RSM-GHS) modeling method. The second-order polynomial function with cross terms is applied to calibrate the time series suspended sediment load with three, four and five input variables in the proposed RSM-GHS. The linear, square and cross corrections of twenty input variables of antecedent values of suspended sediment load and water discharge are investigated to achieve the best predictions of the RSM based on the GHS method. The performances of the NN, RSM and proposed RSM-GHS including both accuracy and simplicity are compared through several comparative predicted and error statistics. The results illustrated that the proposed RSM-GHS is as uncomplicated as the RSM but performed better, where fewer errors and better correlation was observed (R = 0.95, MAE = 18.09 (ton/day), RMSE = 25.16 (ton/day)) compared to the ANN (R = 0.91, MAE = 20.17 (ton/day), RMSE = 33.09 (ton/day)) and RSM (R = 0.91, MAE = 20.06 (ton/day), RMSE = 31.92 (ton/day)) for all types of input variables.

Turbidity threshold sampling for suspended sediment load estimation

Science.gov (United States)

Jack Lewis; Rand Eads

2001-01-01

Abstract - The paper discusses an automated procedure for measuring turbidity and sampling suspended sediment. The basic equipment consists of a programmable data logger, an in situ turbidimeter, a pumping sampler, and a stage-measuring device. The data logger program employs turbidity to govern sample collection during each transport event. Mounting configurations and...

Increased sediment load during a large-scale dam removal changes nearshore subtidal communities.

Directory of Open Access Journals (Sweden)

Stephen P Rubin

Full Text Available The coastal marine ecosystem near the Elwha River was altered by a massive sediment influx-over 10 million tonnes-during the staged three-year removal of two hydropower dams. We used time series of bathymetry, substrate grain size, remotely sensed turbidity, scuba dive surveys, and towed video observations collected before and during dam removal to assess responses of the nearshore subtidal community (3 m to 17 m depth. Biological changes were primarily driven by sediment deposition and elevated suspended sediment concentrations. Macroalgae, predominantly kelp and foliose red algae, were abundant before dam removal with combined cover levels greater than 50%. Where persistent sediment deposits formed, macroalgae decreased greatly or were eliminated. In areas lacking deposition, macroalgae cover decreased inversely to suspended sediment concentration, suggesting impacts from light reduction or scour. Densities of most invertebrate and fish taxa decreased in areas with persistent sediment deposition; however, bivalve densities increased where mud deposited over sand, and flatfish and Pacific sand lance densities increased where sand deposited over gravel. In areas without sediment deposition, most invertebrate and fish taxa were unaffected by increased suspended sediment or the loss of algae cover associated with it; however, densities of tubeworms and flatfish, and primary cover of sessile invertebrates increased suggesting benefits of increased particulate matter or relaxed competition with macroalgae for space. As dam removal neared completion, we saw evidence of macroalgal recovery that likely owed to water column clearing, indicating that long-term recovery from dam removal effects may be starting. Our results are relevant to future dam removal projects in coastal areas and more generally to understanding effects of increased sedimentation on nearshore subtidal benthic communities.

Increased sediment load during a large-scale dam removal changes nearshore subtidal communities

Science.gov (United States)

Rubin, Stephen P.; Miller, Ian M.; Foley, Melissa M.; Berry, Helen D.; Duda, Jeffrey J.; Hudson, Benjamin; Elder, Nancy E.; Beirne, Matthew M.; Warrick, Jonathan; McHenry, Michael L.; Stevens, Andrew; Eidam, Emily; Ogston, Andrea; Gelfenbaum, Guy R.; Pedersen, Rob

2017-01-01

The coastal marine ecosystem near the Elwha River was altered by a massive sediment influx—over 10 million tonnes—during the staged three-year removal of two hydropower dams. We used time series of bathymetry, substrate grain size, remotely sensed turbidity, scuba dive surveys, and towed video observations collected before and during dam removal to assess responses of the nearshore subtidal community (3 m to 17 m depth). Biological changes were primarily driven by sediment deposition and elevated suspended sediment concentrations. Macroalgae, predominantly kelp and foliose red algae, were abundant before dam removal with combined cover levels greater than 50%. Where persistent sediment deposits formed, macroalgae decreased greatly or were eliminated. In areas lacking deposition, macroalgae cover decreased inversely to suspended sediment concentration, suggesting impacts from light reduction or scour. Densities of most invertebrate and fish taxa decreased in areas with persistent sediment deposition; however, bivalve densities increased where mud deposited over sand, and flatfish and Pacific sand lance densities increased where sand deposited over gravel. In areas without sediment deposition, most invertebrate and fish taxa were unaffected by increased suspended sediment or the loss of algae cover associated with it; however, densities of tubeworms and flatfish, and primary cover of sessile invertebrates increased suggesting benefits of increased particulate matter or relaxed competition with macroalgae for space. As dam removal neared completion, we saw evidence of macroalgal recovery that likely owed to water column clearing, indicating that long-term recovery from dam removal effects may be starting. Our results are relevant to future dam removal projects in coastal areas and more generally to understanding effects of increased sedimentation on nearshore subtidal benthic communities.

A chronology of the PY608E-PC sediment core (Lake Pumoyum Co, southern Tibetan Plateau) based on radiocarbon dating of total organic carbon

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Takahiro, E-mail: twatanabe@geo.kankyo.tohoku.ac.jp [Graduate School of Environmental Studies, Tohoku University, 6-6-20 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 (Japan); Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan); Nakamura, Toshio [Center for Chronological Research, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601 (Japan); Matsunaka, Tetsuya [School of Marine Science and Technology, Tokai University, 3-20-1 Orido, Shimizu, Shizuoka 424-0902 (Japan); Nara, Fumiko Watanabe [Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan); Zhu Liping; Wang Junbo [Institute of Tibetan Plateau Research, Chinese Academy of Science, No. 18 Shuangqing Road, Haidian District, Beijing 100085 (China); Kakegawa, Takeshi [Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan); Nishimura, Mitsugu [School of Marine Science and Technology, Tokai University, 3-20-1 Orido, Shimizu, Shizuoka 424-0902 (Japan)

2013-01-15

Paleoclimatic records from the Tibetan Plateau provide important clues for understanding the Asian monsoon and Asian climate systems. To reconstruct climatic and environmental changes in the southern Tibetan Plateau, a 3.77-m-long sediment core (PY608E-PC) was taken from the southeastern part of Lake Pumoyum Co in August 2006. Because terrestrial plant residues are extremely rare in this core, we performed radiocarbon dating on the total organic carbon fraction. We also estimated the old carbon effect and radiocarbon reservoir age of the total organic carbon fraction. Using these estimates, we propose a new radiocarbon chronology for past climatic changes from ca. 12,500 to 700 cal BP. The linear sedimentation rate of the core was founded to be constant at 32.0 cm/kyr, indicating stable sedimentation conditions in Lake Pumoyum Co from the period of the Younger Dryas to the Holocene.

A chronology of the PY608E–PC sediment core (Lake Pumoyum Co, southern Tibetan Plateau) based on radiocarbon dating of total organic carbon

International Nuclear Information System (INIS)

Watanabe, Takahiro; Nakamura, Toshio; Matsunaka, Tetsuya; Nara, Fumiko Watanabe; Zhu Liping; Wang Junbo; Kakegawa, Takeshi; Nishimura, Mitsugu

2013-01-01

Paleoclimatic records from the Tibetan Plateau provide important clues for understanding the Asian monsoon and Asian climate systems. To reconstruct climatic and environmental changes in the southern Tibetan Plateau, a 3.77-m-long sediment core (PY608E–PC) was taken from the southeastern part of Lake Pumoyum Co in August 2006. Because terrestrial plant residues are extremely rare in this core, we performed radiocarbon dating on the total organic carbon fraction. We also estimated the old carbon effect and radiocarbon reservoir age of the total organic carbon fraction. Using these estimates, we propose a new radiocarbon chronology for past climatic changes from ca. 12,500 to 700 cal BP. The linear sedimentation rate of the core was founded to be constant at 32.0 cm/kyr, indicating stable sedimentation conditions in Lake Pumoyum Co from the period of the Younger Dryas to the Holocene.

Sediment quality and ecorisk assessment factors for a major river system

International Nuclear Information System (INIS)

Johnson, V.G.; Wagner, J.J.; Cutshall, N.H.

1993-08-01

Sediment-related water quality and risk assessment parameters for the Columbia River were developed using heavy metal loading and concentration data from Lake Roosevelt (river km 1120) to the mouth and adjacent coastal zone. Correlation of Pb, Zn, Hg, and Cd concentrations in downstream sediments with refinery operations in British Columbia suggest that solutes with K d 's > 10 5 reach about 1 to 5 μg/g per metric ton/year of input. A low-suspended load (upriver avg. <10 mg/L) and high particle-surface reactivity account for the high clay-fraction contaminant concentrations. In addition, a sediment exposure path was demonstrated based on analysis of post-shutdown biodynamics of a heavy metal radiotracer. The slow decline in sediment was attributed to resuspension, bioturbation, and anthropogenic disturbances. The above findings suggest that conservative sediment quality criteria should be used to restrict additional contaminant loading in the upper drainage basin. The issuance of an advisory for Lake Roosevelt, due in part to Hg accumulation in large sport fish, suggests more restrictive controls are needed. A monitoring strategy for assessing human exposure potential and the ecological health of the river is proposed

Assessing sediment contamination using six toxicity assays

OpenAIRE

Allen G. BURTON Jr.; Carolyn ROWLAND; Renato BAUDO; Monica BELTRAMI

2001-01-01

An evaluation of sediment toxicity at Lake Orta, Italy was conducted to compare a toxicity test battery of 6 assays and to evaluate the extent of sediment contamination at various sediment depths. Lake Orta received excessive loadings of copper and ammonia during the 1900’s until a large remediation effort was conducted in 1989-90 using lime addition. Since that time, the lake has shown signs of a steady recovery of biological communities. The study results showed acute toxicity still exists ...

Characterization of water and lake sediments in Laguna de Bay

International Nuclear Information System (INIS)

San Diego, Cherry Ann; Francisco, Pattrice Armynne; Navoa, Joshua Antonio; Johnson, Bryan; Dave, Harshil; Cryer, Karl; Panemanglor, Rajeev; Rama, Mariecar; Sucgang, Raymond J.

2011-01-01

In this work we studied elemental distributions of trace elements, dissolved oxygen and microbiological allotment (total plate count, Coliform, and E. coli) in sediment and surface water from 3 sites in Laguna de Bay. The measured parameters were associated with the quality of the water and to anthropogenic and geogenic processes taking place in the lake. In all cases sediment samples were collected and analyzed for elemental composition using an X-ray fluorescence technique. Water samples were collected and analyzed for nitrate, chloride, and sulfate ions using selective electrodes. Bicarbonate ions in the lake water were determined by titration. The microbial load (total plate count, total coliform and E,. Coli) were determined using Simplate. Field parameters such as pH and conductivity were likewise measured. Preliminary assumptions suggest that proximity to anthropogenic sources has substantially contributed to the combined loads of major ions pollution in the lake. Laguna de Bay is classified as Class C (DENR Administrative Order No. 34). For all the sites, the conductivity of the water were considerably elevated, which ranged from 929 to 933 uS/cm; Site 1 water exceeded the permissible range for pH for Class C water which is 6.5 to 8.5 for the support and rearing of fish. None of the lake waters exceeded the limits for the ions, chloride (set at 350 mg/L) and nitrate (set at 10 mg/L), for Class C water criteria. All the sites meet the dissolved oxygen, DO, criterion for Class C waters which is set at 5 mg/L. In terms of microbiological load, Site 1 had the least most probable number per ml of water, MPN/ml: total plate count (6720), Coliform (less that detection limit) and E. coli (less than LLD); Site 3 was the most contaminated: total plate count (greater than 70,000), Coliform(48768) and E. Coli (23808). X-ray fluorescence analyses of sediments allowed the determination of elements Na, Mg, Al, P, Si, Cl, K. Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Br, Rb

A suspended sediment yield predictive equation for river basins in ...

African Journals Online (AJOL)

The fit was found to be better than those relating mean annual specific suspended sediment yield to basin area or runoff only. Since many stream gauging stations in the country have no records on fluvial sediment, the empirical equation can be used to obtain preliminary estimates of expected sediment load of streams for ...

Knee Joint Loads and Surrounding Muscle Forces during Stair Ascent in Patients with Total Knee Replacement

Science.gov (United States)

Rasnick, Robert; Standifird, Tyler; Reinbolt, Jeffrey A.; Cates, Harold E.

2016-01-01

Total knee replacement (TKR) is commonly used to correct end-stage knee osteoarthritis. Unfortunately, difficulty with stair climbing often persists and prolongs the challenges of TKR patents. Complete understanding of loading at the knee is of great interest in order to aid patient populations, implant manufacturers, rehabilitation, and future healthcare research. Musculoskeletal modeling and simulation approximates joint loading and corresponding muscle forces during a movement. The purpose of this study was to determine if knee joint loadings following TKR are recovered to the level of healthy individuals, and determine the differences in muscle forces causing those loadings. Data from five healthy and five TKR patients were selected for musculoskeletal simulation. Variables of interest included knee joint reaction forces (JRF) and the corresponding muscle forces. A paired samples t-test was used to detect differences between groups for each variable of interest (pknee extension moment and muscle forces during the loading response phase indicates the presence of deficits in TKR in quadriceps muscle force production during stair ascent. This result combined with greater flexor muscle forces resulted in similar compressive JRF during loading response between groups. PMID:27258086

Simulation of contaminated sediment transport in White Oak Creek basin

International Nuclear Information System (INIS)

Bao, Y.; Clapp, R.B.; Brenkert, A.L.; Moore, T.D.; Fontaine, T.A.

1995-01-01

This paper presents a systematic approach to management of the contaminated sediments in the White Oak Creek watershed at Oak Ridge National Laboratory near Oak Ridge, Tennessee. The primary contaminant of concern is radioactive cesium-137 ( 137 Cs), which binds to soil and sediment particles. The key components in the approach include an intensive sampling and monitoring system for flood events; modeling of hydrological processes, sediment transport, and contaminant flux movement; and a decision framework with a detailed human health risk analysis. Emphasis is placed on modeling of watershed rainfall-runoff and contaminated sediment transport during flooding periods using the Hydrologic Simulation Program- Fortran (HSPF) model. Because a large number of parameters are required in HSPF modeling, the major effort in the modeling process is the calibration of model parameters to make simulation results and measured values agree as closely as possible. An optimization model incorporating the concepts of an expert system was developed to improve calibration results and efficiency. Over a five-year simulation period, the simulated flows match the observed values well. Simulated total amount of sediment loads at various locations during storms match with the observed values within a factor of 1.5. Simulated annual releases of 137 Cs off-site locations match the data within a factor of 2 for the five-year period. The comprehensive modeling approach can provide a valuable tool for decision makers to quantitatively analyze sediment erosion, deposition, and transport; exposure risk related to radionuclides in contaminated sediment; and various management strategies

Proactive Semantic Interference is Associated with Total and Regional Abnormal Amyloid Load in Non-Demented Community-Dwelling Elders: A Preliminary Study.

Science.gov (United States)

Loewenstein, David A; Greig, Maria T; Curiel, Rosie; Rodriguez, Rosemarie; Wicklund, Meredith; Barker, Warren W; Hidalgo, Jacqueline; Rosado, Marian; Duara, Ranjan

2015-12-01

To evaluate the relationship between susceptibility to proactive semantic interference (PSI) and retroactive semantic interference (RSI) and brain amyloid load in non-demented elders. 27 participants (11 cognitively normal [CN] with subjective memory complaints, 8 CN without memory complaints, and 8 with mild cognitive impairment [MCI]) underwent complete neurological and neuropsychological evaluations. Participants also received the Semantic Interference Test (SIT) and AV-45 amyloid PET imaging. High levels of association were present between total amyloid load, regional amyloid levels, and the PSI measure (in the entire sample and a subsample excluding MCI subjects). RSI and other memory measures showed much weaker associations or no associations with total and regional amyloid load. No associations between amyloid levels and non-memory performance were observed. In non-demented individuals, vulnerability to PSI was highly associated with total and regional beta-amyloid load and may be an early cognitive marker of brain pathology. Copyright © 2015 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

Human deforestation outweighs future climate change impacts of sedimentation on coral reefs

NARCIS (Netherlands)

Maina, J.; de Moel, H.; Zinke, J.; Madin, J.S.; McClanahan, T.K.; Vermaat, J.E.

2013-01-01

Near-shore coral reef systems are experiencing increased sediment supply due to conversion of forests to other land uses. Counteracting increased sediment loads requires an understanding of the relationship between forest cover and sediment supply, and how this relationship might change in the

Distribution and partitioning of heavy metals in estuarine sediment cores and implications for the use of sediment quality standards

Directory of Open Access Journals (Sweden)

K. L. Spencer

2002-01-01

Full Text Available Total metal concentrations in surface sediments and historically contaminated sediments were determined in sediment cores collected from three estuaries (Thames, Medway and Blackwater in south-east England. The partitioning behaviour of metals in these sediments was also determined using a sequential extraction scheme. These data were then compared with sediment quality values (SQVs to determine the potential ecotoxicological risk to sediment dwelling organisms. When total metal concentrations in surface sediments are examined, no risk to biota in any of the estuaries is indicated. However, when historically contaminated sediments at depth are also considered, risks to biota are apparent and are greatest for the Thames, followed by the Medway and then the Blackwater. This suggests that regulatory authorities should examine vertical metal profiles, particularly in estuaries that are experiencing low sediment accumulation rates where historically contaminated sediments are in the shallow sub-surface zone and where erosion or dredging activities may take place. When metal partitioning characteristics are also considered, the risk to biota is comparable for the Medway and the Blackwater with the potentially bioavailable fraction presenting no ecotoxicological risk. Conversely, over 70% of metals are labile in the Thames Estuary sediments and toxic effects are probable. This suggests that the application of SQVs using total sediment metal concentrations may over- or under-estimate the risk to biota in geochemically dissimilar estuarine sediments. Keywords: sediment quality values, estuarine sediments, metal contamination, partitioning, sequential extraction

Human deforestation outweighs future climate change impacts of sedimentation on coral reefs.

Science.gov (United States)

Maina, Joseph; de Moel, Hans; Zinke, Jens; Madin, Joshua; McClanahan, Tim; Vermaat, Jan E

2013-01-01

Near-shore coral reef systems are experiencing increased sediment supply due to conversion of forests to other land uses. Counteracting increased sediment loads requires an understanding of the relationship between forest cover and sediment supply, and how this relationship might change in the future. Here we study this relationship by simulating river flow and sediment supply in four watersheds that are adjacent to Madagascar's major coral reef ecosystems for a range of future climate change projections and land-use change scenarios. We show that by 2090, all four watersheds are predicted to experience temperature increases and/or precipitation declines that, when combined, result in decreases in river flow and sediment load. However, these climate change-driven declines are outweighed by the impact of deforestation. Consequently, our analyses suggest that regional land-use management is more important than mediating climate change for influencing sedimentation of Malagasy coral reefs.

First-order control of syntectonic sedimentation on crustal-scale structure of mountain belts

Science.gov (United States)

Erdős, Zoltán.; Huismans, Ritske S.; van der Beek, Peter

2015-07-01

The first-order characteristics of collisional mountain belts and the potential feedback with surface processes are predicted by critical taper theory. While the feedback between erosion and mountain belt structure has been fairly extensively studied, less attention has been given to the potential role of synorogenic deposition. For thin-skinned fold-and-thrust belts, recent studies indicate a strong control of syntectonic deposition on structure, as sedimentation tends to stabilize the thin-skinned wedge. However, the factors controlling basement deformation below fold-and-thrust belts, as evident, for example, in the Zagros Mountains or in the Swiss Alps, remain largely unknown. Previous work has suggested that such variations in orogenic structure may be explained by the thermotectonic "age" of the deforming lithosphere and hence its rheology. Here we demonstrate that sediment loading of the foreland basin area provides an additional control and may explain the variable basement involvement in orogenic belts. When examining the role of sedimentation, we identify two end-members: (1) sediment-starved orogenic systems with thick-skinned basement deformation in an axial orogenic core and thin-skinned deformation in the bordering forelands and (2) sediment-loaded orogens with thick packages of synorogenic deposits, derived from the axial basement zone, deposited on the surrounding foreland fold-and-thrust belts, and characterized by basement deformation below the foreland. Using high-resolution thermomechanical models, we demonstrate a strong feedback between deposition and crustal-scale thick-skinned deformation. Our results show that the loading effects of syntectonic sediments lead to long crustal-scale thrust sheets beneath the orogenic foreland and explain the contrasting characteristics of sediment-starved and sediment-loaded orogens, showing for the first time how both thin- and thick-skinned crustal deformations are linked to sediment deposition in these

Sediment tolerance mechanisms identified in sponges using advanced imaging techniques

Directory of Open Access Journals (Sweden)

Brian W. Strehlow

2017-11-01

Full Text Available Terrestrial runoff, resuspension events and dredging can affect filter-feeding sponges by elevating the concentration of suspended sediments, reducing light intensity, and smothering sponges with sediments. To investigate how sponges respond to pressures associated with increased sediment loads, the abundant and widely distributed Indo-Pacific species Ianthella basta was exposed to elevated suspended sediment concentrations, sediment deposition, and light attenuation for 48 h (acute exposure and 4 weeks (chronic exposure. In order to visualise the response mechanisms, sponge tissue was examined by 3D X-ray microscopy and scanning electron microscopy (SEM. Acute exposures resulted in sediment rapidly accumulating in the aquiferous system of I. basta, although this sediment was fully removed within three days. Sediment removal took longer (>2 weeks following chronic exposures, and I. basta also exhibited tissue regression and a smaller aquiferous system. The application of advanced imaging approaches revealed that I. basta employs a multilevel system for sediment rejection and elimination, containing both active and passive components. Sponges responded to sediment stress through (i mucus production, (ii exclusion of particles by incurrent pores, (iii closure of oscula and pumping cessation, (iv expulsion of particles from the aquiferous system, and (v tissue regression to reduce the volume of the aquiferous system, thereby entering a dormant state. These mechanisms would result in tolerance and resilience to exposure to variable and high sediment loads associated with both anthropogenic impacts like dredging programs and natural pressures like flood events.

Mercury and methylmercury concentrations and loads in the Cache Creek watershed, California

Energy Technology Data Exchange (ETDEWEB)

Domagalski, Joseph L.; Alpers, Charles N.; Slotton, Darell G.; Suchanek, Thomas H.; Ayers, Shaun M

2004-07-05

Concentrations and loads of total mercury and methylmercury were measured in streams draining abandoned mercury mines and in the proximity of geothermal discharge in the Cache Creek watershed of California during a 17-month period from January 2000 through May 2001. Rainfall and runoff were lower than long-term averages during the study period. The greatest loading of mercury and methylmercury from upstream sources to downstream receiving waters, such as San Francisco Bay, generally occurred during or after winter rainfall events. During the study period, loads of mercury and methylmercury from geothermal sources tended to be greater than those from abandoned mining areas, a pattern attributable to the lack of large precipitation events capable of mobilizing significant amounts of either mercury-laden sediment or dissolved mercury and methylmercury from mine waste. Streambed sediments of Cache Creek are a significant source of mercury and methylmercury to downstream receiving bodies of water. Much of the mercury in these sediments is the result of deposition over the last 100-150 years by either storm-water runoff, from abandoned mines, or continuous discharges from geothermal areas. Several geochemical constituents were useful as natural tracers for mining and geothermal areas, including the aqueous concentrations of boron, chloride, lithium and sulfate, and the stable isotopes of hydrogen and oxygen in water. Stable isotopes of water in areas draining geothermal discharges showed a distinct trend toward enrichment of {sup 18}O compared with meteoric waters, whereas much of the runoff from abandoned mines indicated a stable isotopic pattern more consistent with local meteoric water.

Mercury and methylmercury concentrations and loads in the Cache Creek watershed, California

International Nuclear Information System (INIS)

Domagalski, Joseph L.; Alpers, Charles N.; Slotton, Darell G.; Suchanek, Thomas H.; Ayers, Shaun M.

2004-01-01

Concentrations and loads of total mercury and methylmercury were measured in streams draining abandoned mercury mines and in the proximity of geothermal discharge in the Cache Creek watershed of California during a 17-month period from January 2000 through May 2001. Rainfall and runoff were lower than long-term averages during the study period. The greatest loading of mercury and methylmercury from upstream sources to downstream receiving waters, such as San Francisco Bay, generally occurred during or after winter rainfall events. During the study period, loads of mercury and methylmercury from geothermal sources tended to be greater than those from abandoned mining areas, a pattern attributable to the lack of large precipitation events capable of mobilizing significant amounts of either mercury-laden sediment or dissolved mercury and methylmercury from mine waste. Streambed sediments of Cache Creek are a significant source of mercury and methylmercury to downstream receiving bodies of water. Much of the mercury in these sediments is the result of deposition over the last 100-150 years by either storm-water runoff, from abandoned mines, or continuous discharges from geothermal areas. Several geochemical constituents were useful as natural tracers for mining and geothermal areas, including the aqueous concentrations of boron, chloride, lithium and sulfate, and the stable isotopes of hydrogen and oxygen in water. Stable isotopes of water in areas draining geothermal discharges showed a distinct trend toward enrichment of 18 O compared with meteoric waters, whereas much of the runoff from abandoned mines indicated a stable isotopic pattern more consistent with local meteoric water

Analysis in crab tissues and in sediment of estuary from Iguape (Sao Paulo, Brazil) by total reflection X-ray fluorescence

International Nuclear Information System (INIS)

Salvador, Marcos J.; Sawazaki, David T.A.; Zucchi, Orgheda L.A. Domingues; Vives, Ana Elisa S. de; Hattori, Gustavo Y.

2007-01-01

We report the use of Synchrotron Radiation Total Reflection X-Ray Fluorescence analysis (SR-TXRF) as a technique for macro, micro and trace elements determination in the tissues of the crab Ulcides cordatus and in the sediments from the Iguape estuary (Sao Paulo, Brazil) for environmental pollution control and toxicological evaluation. The analyses were performed on the U. cordatus (muscles and hepatopancreas) and on sediments from 24 sites of the Iguape estuary (Sao Paulo, Brazil). Tissues and sediments samples were analyzed by SRTXRF after digestion in an open system, using Ga as internal standard. Potassium (K), Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr, and Ba were the elements detected in crab hepatopancreas at concentration ranging from 0.516 (Mn) to 2061 (K) mug/g. Muscles samples presented the elements K, Ca, Ti, V, Cr, Fe, Ni, Cu, Zn, Br and Sr at concentrations ranging from 0.043 (Ni) to 1917 (K) mug/g. Potassium (K), Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Sn, Ce, and Pb were the elements detected in the sediment samples with concentration between 3.8 (Cu) and 14628 (Fe)mug/g. (author)

Analysis in crab tissues and in sediment of estuary from Iguape (Sao Paulo, Brazil) by total reflection X-ray fluorescence

Energy Technology Data Exchange (ETDEWEB)

Salvador, Marcos J. [Universidade do Vale do Paraiba (UNIVAP), Sao Jose dos Campos, SP (Brazil)], E-mail: mjsalvador1531@yahoo.com.br; Sawazaki, David T.A.; Zucchi, Orgheda L.A. Domingues [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas], E-mail: david_tatsuo@hotmail.com, E-mail: olzucchi@fcfrp.usp.br; Vives, Ana Elisa S. de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo], E-mail: aesvives@unimep.br; Hattori, Gustavo Y. [Universidade Federal do Amazonas, Benjamin Constant (Brazil). Faculdade de Ciencias Agrarias], E-mail: hattori@ufam.edu.br

2007-07-01

We report the use of Synchrotron Radiation Total Reflection X-Ray Fluorescence analysis (SR-TXRF) as a technique for macro, micro and trace elements determination in the tissues of the crab Ulcides cordatus and in the sediments from the Iguape estuary (Sao Paulo, Brazil) for environmental pollution control and toxicological evaluation. The analyses were performed on the U. cordatus (muscles and hepatopancreas) and on sediments from 24 sites of the Iguape estuary (Sao Paulo, Brazil). Tissues and sediments samples were analyzed by SRTXRF after digestion in an open system, using Ga as internal standard. Potassium (K), Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr, and Ba were the elements detected in crab hepatopancreas at concentration ranging from 0.516 (Mn) to 2061 (K) mug/g. Muscles samples presented the elements K, Ca, Ti, V, Cr, Fe, Ni, Cu, Zn, Br and Sr at concentrations ranging from 0.043 (Ni) to 1917 (K) mug/g. Potassium (K), Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Sn, Ce, and Pb were the elements detected in the sediment samples with concentration between 3.8 (Cu) and 14628 (Fe)mug/g. (author)

Ecological effects and chemical composition of fine sediments in Upper Austrian streams and resulting implications for river management

Science.gov (United States)

Höfler, Sarah; Pichler-Scheder, Christian; Gumpinger, Clemens

2017-04-01