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1

Sediment data sources and estimated annual suspended-sediment loads of rivers and streams in Colorado  

USGS Publications Warehouse

Sources of sediment data collected by several government agencies through water year 1984 are summarized for Colorado. The U.S. Geological Survey has collected suspended-sediment data at 243 sites; these data are stored in the U.S. Geological Survey 's water data storage and retrieval system. The U.S. Forest Service has collected suspended-sediment and bedload data at an additional 225 sites, and most of these data are stored in the U.S. Environmental Protection Agency 's water-quality-control information system. Additional unpublished sediment data are in the possession of the collecting entities. Annual suspended-sediment loads were computed for 133 U.S. Geological Survey sediment-data-collection sites using the daily mean water-discharge/sediment-transport-curve method. Sediment-transport curves were derived for each site by one of three techniques: (1) Least-squares linear regression of all pairs of suspended-sediment and corresponding water-discharge data, (2) least-squares linear regression of data sets subdivided on the basis of hydrograph season; and (3) graphical fit to a logarithm-logarithm plot of data. The curve-fitting technique used for each site depended on site-specific characteristics. Sediment-data sources and estimates of annual loads of suspended, bed, and total sediment from several other reports also are summarized. (USGS)

Elliott, J.G.; DeFeyter, K.L.

1986-01-01

2

TOTAL AND BIOAVAILABLE METALS AT MARINA SEDIMENTS IN LAKE TEXOMA  

EPA Science Inventory

Total and bioavailable metals in sediments were measured at marina areas in Lake Texoma during the fall of 2001. The metals most often found in the highest concentrations in sediments were Ca (56811 mg/kg) and Al (31095 mg/kg), followed by Fe (19393 mg/kg), K (6089 mg/kg), and Mg...

3

Sediment and Total Phosphorous Contributors in Rock River Watershed  

EPA Science Inventory

Total phosphorous (TP) and total suspended sediment (TSS) pollution is a problem in the US Midwest and is of particular concern in the Great Lakes region where many water bodies are already eutrophic. Increases in monoculture corn planting to feed ethanol based biofuel productio...

4

The measurement of total sediment load in alluvial streams  

USGS Publications Warehouse

The measurement of the total sediment load transported by streams that flow in alluvial channels has been a perplexing problem to engineers and geologists for over a century. Until the last decade the development of equipment to measure bed load and suspended load was carried on almost independently, and without primary consideration of the fundamental laws governing the transportation of fluvial sediments. French investigators during the nineteenth century described methods of measurement and a mathematical approach for computing the rate of bed-load movement. The comprehensive laboratory investigations by Gilbert early in this century provided data that are still being used for studies of sediment transport. Detailed laboratory investigations of bed-load movement conducted during the last two decades by a number of investigators have resulted in the development of additional mathematical formulas for computing rates of bed-load movement. Likewise, studies of turbulent flow have provided the turbulence suspension theory for suspended sediment as it is known today.

Benedict, P.C.; Matejka, D.Q.

1953-01-01

5

Concentrations, loads, and yields of total phosphorus, total nitrogen, and suspended sediment and bacteria concentrations in the Wister Lake Basin, Oklahoma and Arkansas, 2011-13  

USGS Publications Warehouse

The Poteau Valley Improvement Authority uses Wister Lake in southeastern Oklahoma as a public water supply. Total phosphorus, total nitrogen, and suspended sediments from agricultural runoff and discharges from wastewater treatment plants and other sources have degraded water quality in the lake. As lake-water quality has degraded, water-treatment cost, chemical usage, and sludge production have increased for the Poteau Valley Improvement Authority. The U.S. Geological Survey (USGS), in cooperation with the Poteau Valley Improvement Authority, investigated and summarized concentrations of total phosphorus, total nitrogen, suspended sediment, and bacteria (Escherichia coli and Enterococcus sp.) in surface water flowing to Wister Lake. Estimates of total phosphorus, total nitrogen, and suspended sediment loads, yields, and flow-weighted mean concentrations of total phosphorus and total nitrogen concentrations were made for the Wister Lake Basin for a 3-year period from October 2010 through September 2013. Data from water samples collected at fixed time increments during base-flow conditions and during runoff conditions at the Poteau River at Loving, Okla. (USGS station 07247015), the Poteau River near Heavener, Okla. (USGS station 07247350), and the Fourche Maline near Leflore, Okla. (USGS station 07247650), water-quality stations were used to evaluate water quality over the range of streamflows in the basin. These data also were collected to estimate annual constituent loads and yields by using regression models. At the Poteau River stations, total phosphorus, total nitrogen, and suspended sediment concentrations in surface-water samples were significantly larger in samples collected during runoff conditions than in samples collected during base-flow conditions. At the Fourche Maline station, in contrast, concentrations of these constituents in water samples collected during runoff conditions were not significantly larger than concentrations during base-flow conditions. Flow-weighted mean total phosphorus concentrations at all three stations from 2011 to 2013 were several times larger than the Oklahoma State Standard for Scenic Rivers (0.037 milligrams per liter [mg/L]), with the largest flow-weighted phosphorus concentrations typically being measured at the Poteau River at Loving, Okla., station. Flow-weighted mean total nitrogen concentrations did not vary substantially between the Poteau River stations and the Fourche Maline near Leflore, Okla., station. At all of the sampled water-quality stations, bacteria (Escherichia coli and Enterococcus sp.) concentrations were substantially larger in water samples collected during runoff conditions than in water samples collected during base-flow conditions from 2011 to 2013. Estimated annual loads of total phosphorus, total nitrogen, and suspended sediment in the Poteau River stations during runoff conditions ranged from 82 to 98 percent of the total annual loads of those constituents. Estimated annual loads of total phosphorus, total nitrogen, and suspended sediment in the Fourche Maline during runoff conditions ranged from 86 to nearly 100 percent of the total annual loads. Estimated seasonal total phosphorus loads generally were smallest during base-flow and runoff conditions in autumn. Estimated seasonal total phosphorus loads during base-flow conditions tended to be largest in winter and during runoff conditions tended to be largest in the spring. Estimated seasonal total nitrogen loads tended to be smallest in autumn during base-flow and runoff conditions and largest in winter during runoff conditions. Estimated seasonal suspended sediment loads tended to be smallest during base-flow conditions in the summer and smallest during runoff conditions in the autumn. The largest estimated seasonal suspended sediment loads during runoff conditions typically were in the spring. The estimated mean annual total phosphorus yield was largest at the Poteau River at Loving, Okla., water-quality station. The estimated mean annual total phosphorus yield was largest during base flow at the

Buck, Stephanie D.

2014-01-01

6

A comparison of load estimates using total suspended solids and suspended-sediment concentration data  

USGS Publications Warehouse

This paper presents the results to-date from a continuing investigation into the differences between total suspended solids (TSS) and suspended-sediment concentration (SSC) data and the ramifications of using each type of data to estimate sediment loads. It compares estimates of annual suspended-sediment loads that were made using regression equations developed from paired TSS and SSC data, to annual loads computed by the U.S. Geological Survey (USGS) using traditional techniques and SSC data. Load estimates were compared for 10 stations where sufficient TSS and SSC paired data were available to develop sediment-transport curves for the same time period that daily suspended-sediment records were available. Results of these analyses indicate that as the time frame over which the estimates were made increases, the overall errors associated with the estimates decreases with respect to loads computed using traditional USGS techniques. Using SSC data to compute loads tends to produce estimates closer to those computed by traditional techniques than those computed from TSS data. Loads computed from TSS data tend to be negatively biased with respect to those computed by traditional USGS techniques.

Glysson, G.D.; Gray, J.R.; Schwarz, G.E.

2001-01-01

7

Annual Sediment Budgets for Newly Formed Point Bars on Powder River, Montana, USA  

NASA Astrophysics Data System (ADS)

Morphodynamic processes have been monitored for 37 years on Powder River, a large, unregulated meandering river that drains an area of about 35,000 km2 in northeastern Wyoming and southeastern Montana, USA. Cross-sectional surveys of the channel and adjacent floodplains and terraces have been measured nearly annually (30 out of 37 years) by the U.S. Geological Survey (USGS) at 24 locations along 90 kilometers of the river. This long-term data set has provided insights into the natural morphological and sedimentary processes; and most recently, into the annual sediment budgets for three point bars that were created when an extreme flood in 1978 cut new channels across the necks of two former meander bends and radically shifted the location of a third bend. Because our cross-sectional surveys are generally made only once a year (during the low-flow period, usually September-October), we record only the net change in thickness of the annual deposition and erosion because some areas on a point bar may be scoured and refilled during multiple floods in a year. Point-bar sediment budgets vary spatially as well as annually. The long-term average of the net annual sediment budgets during the post-1978 years (n=26 surveys) indicates that the average annual increment of new sediment deposited on the three point bars has been three to four times the average annual increment of old sediment eroded from the point bars. This annual deposition-to-erosion ratio has varied at one point bar from a minimum of 0.14 (1986) to maximum of 275 (1995). At the other two point-bar sites the ratio ranged from 0.18 (1991) to 265 (2008) and from 0.023 (1980) to 479 (1987). The lack of correlation from year to year or from one point bar to the next suggests the importance of differences in the planimetric configurations and hydraulic histories of each point bar in the evolutionary process. All the deposited sediment we measured during an annual survey represents the same sediment year class, whereas the eroded sediment we measured is composed of different proportions of previous sediment year classes. An index of the preservation (completeness) of these sediment year classes was defined for each point-bar as the percent of the initial deposit (older than 10 years) that was still remaining in 2011. The average (n=20 surveys) completeness was 59, 81, and 64%, and in general, deposits had better chances for being preserved if they were deposited higher on the point bar surface, or if they were covered by new deposition in the following year. Net annual deposition correlated only weakly with annual peak water discharge, and we found no correlation between annual peak water discharge and the amount of sediment eroded from the point bars. These low correlations may be the result of our using only net deposition and erosion values, and not the total deposition and erosion. These results illustrate the dynamic nature of point bars that adds an important component to earlier uniform, lateral accretion models of point bars. This dynamic nature produces a range of vegetation year classes, and thus, a rich diverse habitat for terrestrial and aquatic populations. This abstract has described one application of this unique long-term data set, and the authors will be pleased to provide the data set to anyone who might need long-term fluvial geomorphic data to address other research questions such as floodplain contaminant storage, river restoration, and environmental change.

Moody, John; Meade, Robert

2013-04-01

8

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

NSDL National Science Digital Library

This site consists of a digital total sediment thickness map and database for the world's oceans and marginal seas. The data are derived from previously published maps, ocean drilling results (Ocean Drilling Program and Deep Sea Drilling Project), and seismic reflection profiles (National Geophysical Data Center archives and Geological/Geophysical Atlas of the Pacific). Features include a JPEG image of the map, a downloadable data set available as either a NetCDF grd file or ASCII file, and bibliographical information.

9

A New Method for the Determination of Annual Sediment Fluxes from Varved Lake Sediments  

NASA Astrophysics Data System (ADS)

Calculation of sediment mass accumulation rates instead of thickness accumulation is preferable for paleoclimatic reconstruction as it eliminates the effects of dilution and compaction. Annually laminated lake sediment sequences (varved) theoretically allow for the estimation of sediment fluxes at annual scale, but the calculation is limited by discrete bulk density measurements, often carried out at a much lower resolution (usually 1 cm) than the varves (ranging from 0.07 to 27.3 mm, average 1.84 mm according to Ojala et al. 2012). Since many years the development of automated logging instruments made available continuous and high resolution sediment property data, in a non-destructive fashion. These techniques can easily be used to extract the physical and chemical parameters of sediments at the varve scale (down to 100 ?m). Here we present a robust method to calculate annual sediment fluxes from varved lake sediments by combining varves thickness measurements to core logging data, and provide an example for its applications. Several non-destructive densitometric methods applied to the Strathcona Lake sediment, northern Ellesmere Island, Canada (78°33'N; 82°05'W) were compared: Hounsfield Units from a CT-Scan, coherent/incoherent ratio and X-ray radiography (of both split core and sediment slabs, from an Itrax core Scanner), and gamma ray attenuation density. Core logging data were statistically compared to 400 discrete measurements of dry bulk density, wet bulk density and water content performed at 2 mm contiguous intervals. A very strong relationship was found between X-ray grey level on sediment slab and dry bulk density. Relative X-ray densities, at 100?m resolution, were then successfully calibrated against real densities. The final step consisted in binning the calibrated densities to the corresponding varve thickness and then to calculate the annual mass accumulation rates by multiplying the two parameters for each varve year. Strathcona Lake is located directly downstream of the Agassiz ice cap and contains laminated sediments whose accumulation is directly related to hydrological inputs generated by the melting of the ice cap. Over the last 65 years, annual sediment accumulation rates in Strathcona Lake documented an increase in high-energy hydrologic discharge events from 1990 to 2009. This timing is in agreement with evidence for an increase in the amount of melt on the adjacent Agassiz Ice Cap, as recorded in ice cores. A good correspondence was also found between annual mass accumulation rates and Eureka air temperature records, suggesting that temperature changes affected the extent of summer melting on the Agassiz Ice Cap, leading to high sediment yield to Strathcona Lake. Ojala, A.E.K., Francus, P., Zolitschka, B., Besonen, M. and Lamoureux, S.F. (2012) Characteristics of sedimentary varve chronologies - A review. Quaternary Science Reviews, 43, 45-60.

Francus, P.; Massa, C.; Lapointe, F.

2013-12-01

10

Further Evaluation of an Emperical Equation for Annual Total Evaporation  

NASA Technical Reports Server (NTRS)

An empirical equation for annual total evaporation based on annual precipitation and net radiation was found to provide evaporation within 10% of the observed values at seven locations within temperate and tropical regions, but it overestimated evaporation by 90% at one location within the tundra region. A synthesis of observations at two other locations within the tundra region gives overestimates of about 65%. A general analysis of observed precipitation, net radiation, and runoff within the tundra region shows that the empirical equation is generally biased to overestimate annual evaporation within the tundra region. A theoretical analysis is being done to understand the reason behind this bias.

Choudhury, Bhaskar J.

1999-01-01

11

A study of the occurrence and distribution of bdellovibrios in estuarine sediment over an annual cycle  

Microsoft Academic Search

The recovery of bdellovibrios from estuarine sediments over an annual cycle was studied. Greater numbers of the predators were recovered in sediment than in the water column. Increases in the number of bdellovibrios recovered from sediment over various periods of time suggest that multiplication of the predators occurred. Sediment was observed to be an important ecosystem for the survival of

H. N. Williams

1988-01-01

12

EVALUATION OF A FLUOROMETRIC SCREENING METHOD FOR PREDICTING TOTAL PAH CONCENTRATIONS IN CONTAMINATED SEDIMENTS  

EPA Science Inventory

A flurorometric screening method was used to estimate total polycyclic aromatic hydrocarbon concentrations in sediments collected from the St. Louis River Area of Concern in northeastern Minnesota. Sediments were collected as part of a Regional Environmental Monitoring and Asses...

13

Soil respiration at mean annual temperature predicts annual total across vegetation types and biomes  

PubMed Central

Soil respiration (SR) constitutes the largest flux of CO2 from terrestrial ecosystems to the atmosphere. However, there still exist considerable uncertainties as to its actual magnitude, as well as its spatial and interannual variability. Based on a reanalysis and synthesis of 80 site-years for 57 forests, plantations, savannas, shrublands and grasslands from boreal to tropical climates we present evidence that total annual SR is closely related to SR at mean annual soil temperature (SRMAT), irrespective of the type of ecosystem and biome. This is theoretically expected for non water-limited ecosystems within most of the globally occurring range of annual temperature variability and sensitivity (Q10). We further show that for seasonally dry sites where annual precipitation (P) is lower than potential evapotranspiration (PET), annual SR can be predicted from wet season SRMAT corrected for a factor related to P/PET. Our finding indicates that it can be sufficient to measure SRMAT for obtaining a well constrained estimate of its annual total. This should substantially increase our capacity for assessing the spatial distribution of soil CO2 emissions across ecosystems, landscapes and regions, and thereby contribute to improving the spatial resolution of a major component of the global carbon cycle. PMID:23293656

Bahn, M.; Reichstein, M.; Davidson, E. A.; Grünzweig, J.; Jung, M.; Carbone, M. S.; Epron, D.; Misson, L.; Nouvellon, Y.; Roupsard, O.; Savage, K.; Trumbore, S. E.; Gimeno, C.; Yuste, J. Curiel; Tang, J.; Vargas, R.; Janssens, I. A.

2011-01-01

14

Soil respiration at mean annual temperature predicts annual total across vegetation types and biomes.  

PubMed

Soil respiration (SR) constitutes the largest flux of CO(2) from terrestrial ecosystems to the atmosphere. However, there still exist considerable uncertainties as to its actual magnitude, as well as its spatial and interannual variability. Based on a reanalysis and synthesis of 80 site-years for 57 forests, plantations, savannas, shrublands and grasslands from boreal to tropical climates we present evidence that total annual SR is closely related to SR at mean annual soil temperature (SR(MAT)), irrespective of the type of ecosystem and biome. This is theoretically expected for non water-limited ecosystems within most of the globally occurring range of annual temperature variability and sensitivity (Q(10)). We further show that for seasonally dry sites where annual precipitation (P) is lower than potential evapotranspiration (PET), annual SR can be predicted from wet season SR(MAT) corrected for a factor related to P/PET. Our finding indicates that it can be sufficient to measure SR(MAT) for obtaining a well constrained estimate of its annual total. This should substantially increase our capacity for assessing the spatial distribution of soil CO(2) emissions across ecosystems, landscapes and regions, and thereby contribute to improving the spatial resolution of a major component of the global carbon cycle. PMID:23293656

Bahn, M; Reichstein, M; Davidson, E A; Grünzweig, J; Jung, M; Carbone, M S; Epron, D; Misson, L; Nouvellon, Y; Roupsard, O; Savage, K; Trumbore, S E; Gimeno, C; Yuste, J Curiel; Tang, J; Vargas, R; Janssens, I A

2010-07-01

15

Experimental evidence for turbulent sediment flux constituting a large portion of the total sediment flux along migrating sand dunes  

NASA Astrophysics Data System (ADS)

Accurate estimation of sediment transport is critical for many fluvial processes but remains challenging due to high-frequency dynamics. Using novel acoustic flow instrumentation, we quantified the contribution of turbulent bed and suspended sediment fluxes to the total sediment fluxes along an entire dune profile and over the full flow depth. We found that over the dune stoss side and in the bed load layer, the turbulent mean streamwise flux is negative and reaches up to 40% of the total mean streamwise flux. Over the lee side, where turbulent intensities are highest, the contribution of the turbulent mean streamwise flux to the total mean streamwise flux is larger and reaches up to 50%. The mean vertical turbulent flux along the entire dune bed and in the bed load layer reaches nearly 30% of the total mean vertical flux. Turbulent sediment flux may thus constitute a large component of the total flux.

Naqshband, S.; Ribberink, J. S.; Hurther, D.; Barraud, P. A.; Hulscher, S. J. M. H.

2014-12-01

16

29 CFR 779.253 - What is included in computing the total annual inflow volume.  

Code of Federal Regulations, 2012 CFR

...included in computing the total annual inflow volume. 779.253 Section 779.253 Labor...included in computing the total annual inflow volume. The goods which the establishment...State lines must “amount in total annual volume to $250,000 or more.” It will...

2012-07-01

17

29 CFR 779.253 - What is included in computing the total annual inflow volume.  

Code of Federal Regulations, 2013 CFR

...included in computing the total annual inflow volume. 779.253 Section 779.253 Labor...included in computing the total annual inflow volume. The goods which the establishment...State lines must “amount in total annual volume to $250,000 or more.” It will...

2013-07-01

18

29 CFR 779.253 - What is included in computing the total annual inflow volume.  

Code of Federal Regulations, 2014 CFR

...included in computing the total annual inflow volume. 779.253 Section 779.253 Labor...included in computing the total annual inflow volume. The goods which the establishment...State lines must “amount in total annual volume to $250,000 or more.” It will...

2014-07-01

19

Simplified methods for computing total sediment discharge with the modified Einstein procedure  

USGS Publications Warehouse

A procedure was presented in 1950 by H. A. Einstein for computing the total discharge of sediment particles of sizes that are in appreciable quantities in the stream bed. This procedure was modified by the U.S. Geological Survey and adapted to computing the total sediment discharge of a stream on the basis of samples of bed sediment, depth-integrated samples of suspended sediment, streamflow measurements, and water temperature. This paper gives simplified methods for computing total sediment discharge by the modified Einstein procedure. Each of four homographs appreciably simplifies a major step in the computations. Within the stated limitations, use of the homographs introduces much less error than is present in either the basic data or the theories on which the computations of total sediment discharge are based. The results are nearly as accurate mathematically as those that could be obtained from the longer and more complex arithmetic and algebraic computations of the Einstein procedure.

Colby, Bruce R.; Hubbell, David Wellington

1961-01-01

20

Sediment and total phosphorous contributors in Rock River watershed.  

PubMed

Total phosphorous (TP) and total suspended sediment (TSS) pollution is a problem in the US Midwest and is of particular concern in the Great Lakes region where many water bodies are already eutrophic. Increases in monoculture corn planting to feed ethanol based biofuel production could exacerbate these already stressed water bodies. In this study we expand on the previous studies relating landscape variables such as land cover, soil type and slope with changes in pollutant concentrations and loading in the Great Lakes region. The Rock River watershed in Wisconsin, USA was chosen due to its diverse land use, numerous lakes and reservoirs susceptible to TSS and TP pollution, and the availability of long-term streamflow, TSS and TP data. Eight independent subwatersheds in the Rock River watershed were identified using United States Geological Survey (USGS) monitoring sites that monitor flow, TSS and TP. For each subwatershed, we calculated land use, soil type, and terrain slope metrics or variables. TSS and TP from the different subwatersheds were compared using Analysis of Variance (ANOVA), and associations and relationships between landscape metrics and water quality (TSS and TP) were evaluated using the partial least square (PLS) regression. Results show that urban land use and agricultural land growing corn rotated with non-leguminous crops are associated with TSS and TP in streams. This indicates that increasing the amount of corn rotated with non-leguminous crops within a subwatershed could increase degradation of water quality. Results showed that increase in corn-soybean rotation acreage within the watershed is associated with reduction in stream's TSS and TP. Results also show that forest and water bodies were associated with reduction in TSS and TP. Based on our results we recommend adoption of the Low Impact Development (LID) approach in urban dominated subwatersheds. This approach attempts to replicate the pre-development hydrological regime by reducing the ratio of impervious area to natural cover wherever possible, as well as recycling or treating stormwater runoff using filter strips, ponds and wetlands. In agriculturally dominated subwatersheds, we recommend increasing corn-soybean rotation, keeping corn on areas with gentle slope and soils with lower erodibility. PMID:24384283

Mbonimpa, Eric G; Yuan, Yongping; Nash, Maliha S; Mehaffey, Megan H

2014-01-15

21

An Energetics Total Load Sediment Transport Model For a Plane Sloping Beach  

Microsoft Academic Search

Bagnold's energetics-based total load sediment transport model for streams is used as a basis for the development of a total load model of time varying sediment transport over a plane sloping bed. In both the bedload and suspended load, the transport rate vectors are found to be composed of a velocity-induced component directed parallel to the instantaneous velocity vector and

James A. Bailard

1981-01-01

22

Optimal strategies for determination of free/extractable and total microcystins in lake sediment.  

PubMed

The optimization of analytical procedures for the quantification of free and total microcystins (MCs) in natural sediments was systematically examined based on solvent extraction and Lemieux oxidation. In this optimized analytical procedure, a sequential solvent extraction using 50% (v/v) methanol and EDTA-sodium pyrophosphate was selected as the optimal extraction solvent for free MCs analysis, after which the purified extracts and sediment residuals were applied to the optimized Lemieux oxidation for determination of total MCs in lake sediments. The optimized procedures were shown to be efficient and reliable for the routine analysis of both free and total MCs in lake sediment samples, as indicated by the minimal adverse impact of sediment organic matter on the recovery of free MCs and yield of MMPB (2-methyl-3-methoxy-4-phenylbutyric acid). Finally, the developed procedures were applied to field sediment samples collected from Lake Dianchi during a bloom season and seven of thirty samples showed positive results. PMID:22122933

Wu, Xingqiang; Wang, Chunbo; Xiao, Bangding; Wang, Yang; Zheng, Na; Liu, Jingshuang

2012-01-01

23

How many children? – Fixing total annual births as a population control policy  

Microsoft Academic Search

Traditional family planning's emphasis on manipulating the total fertility rate often results in erratic number of births which disrupts school enrollment and labor supply. Fixing total annual births to a permanently lower level will avoid such repeated disruptions and can eventually lead to a lower stationary population with annual deaths equal to the fixed annual births. If allocation of the

K. K. Fung

1998-01-01

24

Lateglacial calendar year chronology based on annually laminated sediments from Lake Meerfelder Maar, Germany  

Microsoft Academic Search

Annually laminated sediments from Lake Meerfelder Maar (MFM) in the Eifel, Germany, provide an independent calendar year timescale for the last glacial\\/interglacial transition. Changes in varve thickness and varve facies reflect significant environment variations during this period. The general micro facies pattern confirms that diatomaceous organic varves are favoured during warm climatic phases while cold periods generate higher allochthonous sediment

Achim Brauer; Christoph Endres; Jörg F. W Negendank

1999-01-01

25

Characteristics of sediment data and annual suspended-sediment loads and yields for selected lower Missouri River mainstem and tributary stations, 1976-2008  

USGS Publications Warehouse

Suspended-sediment data from 18 selected surface-water monitoring stations in the lower Missouri River Basin downstream from Gavins Point Dam were used in the computation of annual suspended-sediment and suspended-sand loads for 1976 through 2008. Three methods of suspended-sediment load determination were utilized and these included the subdivision method, regression of instantaneous turbidity with suspended-sediment concentrations at selected stations, and regression techniques using the Load Estimator (LOADEST) software. Characteristics of the suspended-sediment and streamflow data collected at the 18 monitoring stations and the tabulated annual suspended-sediment and suspended-sand loads and yields are presented.

Heimann, David C.; Rasmussen, Patrick P.; Cline, Teri L.; Pigue, Lori M.; Wagner, Holly R.

2010-01-01

26

Effects of lakes and reservoirs on annual river nitrogen, phosphorus, and sediment export in agricultural and forested landscapes  

USGS Publications Warehouse

Recently, effects of lakes and reservoirs on river nutrient export have been incorporated into landscape biogeochemical models. Because annual export varies with precipitation, there is a need to examine the biogeochemical role of lakes and reservoirs over time frames that incorporate interannual variability in precipitation. We examined long-term (~20?years) time series of river export (annual mass yield, Y, and flow-weighted mean annual concentration, C) for total nitrogen (TN), total phosphorus (TP), and total suspended sediment (TSS) from 54 catchments in Wisconsin, USA. Catchments were classified as small agricultural, large agricultural, and forested by use of a cluster analysis, and these varied in lentic coverage (percentage of catchment lake or reservoir water that was connected to river network). Mean annual export and interannual variability (CV) of export (for both Y and C) were higher in agricultural catchments relative to forested catchments for TP, TN, and TSS. In both agricultural and forested settings, mean and maximum annual TN yields were lower in the presence of lakes and reservoirs, suggesting lentic denitrification or N burial. There was also evidence of long-term lentic TP and TSS retention, especially when viewed in terms of maximum annual yield, suggesting sedimentation during high loading years. Lentic catchments had lower interannual variability in export. For TP and TSS, interannual variability in mass yield was often >50% higher than interannual variability in water yield, whereas TN variability more closely followed water (discharge) variability. Our results indicate that long-term mass export through rivers depends on interacting terrestrial, aquatic, and meteorological factors in which the presence of lakes and reservoirs can reduce the magnitude of export, stabilize interannual variability in export, as well as introduce export time lags.

Powers, Steve M.; Robertson, Dale M.; Stanley, Emily H.

2014-01-01

27

Characterization and Dynamics of Total Suspended Sediments (TSS) along Puerto Rico West Coast  

E-print Network

1 Characterization and Dynamics of Total Suspended Sediments (TSS) along Puerto Rico West Coast Lorenna Vazquez Albelo Geology Department, University of Puerto Rico, Mayagüez Campus, P.O. Box 9017 Mayagüez, Puerto Rico, 00681-9017 ABSTRACT.- This project intended to investigate and describe sediment

Gilbes, Fernando

28

Total Arsenic in Sediments from the Western North Sea and the Humber Estuary  

Microsoft Academic Search

In previous surveys of North Sea sediments, arsenic has often been omitted from the range of metals analysed. In this study we analysed archived samples from these earlier surveys and combined the data with recent results for the Dogger Bank, to examine the distribution of total arsenic in sediments from the western North Sea and Humber Estuary. Historically, the Humber

Caroline Whalley; Steve Rowlatt; Moira Bennett; Dave Lovell

1999-01-01

29

TOTAL ORGANIC CARBON IN LAKE SUPERIOR SEDIMENTS: COMPARISONS WITH HEMIPELAGIC AND PELAGIC MARINE ENVIRONMENTS  

EPA Science Inventory

Seventeen box cores from Lake Superior were analyzed for total organic carbon (TOC), porosity, and (210)Pb activity. The data were used to determine relationships among bulk sedimentation rates, TOC sedimentation rates, and TOC degradation rates with depth in the core. Results ar...

30

Distribution of total mercury and methyl mercury in water, sediment, and fish from South Florida estuaries  

USGS Publications Warehouse

Concentrations of total mercury and methyl mercury were determined in sediment and fish collected from estuarine waters of Florida to understand their distribution and partitioning. Total mercury concentrations in sediments ranged from 1 to 219 ng/g dry wt. Methyl mercury accounted for, on average, 0.77% of total mercury in sediment. Methyl mercury concentrations were not correlated with total mercury or organic carbon content in sediments. The concentrations of total mercury in fish muscle were between 0.03 and 2.22 (mean: 0.31) ??g/g, wet wt, with methyl mercury contributing 83% of total mercury. Methyl mercury concentrations in fish muscle were directly proportional to total mercury concentrations. The relationship of total and methyl mercury concentrations in fish to those of sediments from corresponding locations was fish-species dependent, in addition to several abiotic factors. Among fish species analyzed, hardhead catfish, gafftopsail catfish, and sand seatrout contained the highest concentrations of mercury. Filtered water samples from canals and creeks that discharge into the Florida Bay showed mercury concentrations of 3-7.4 ng/L, with methyl mercury accounting for <0.03-52% of the total mercury. Consumption of fish containing 0.31 ??g mercury/g wet wt, the mean concentration found in this study, at rates greater than 70 g/day, was estimated to be hazardous to human health.

Kannan, K.; Smith, R.G., Jr.; Lee, R.F.; Windom, H.L.; Heitmuller, P.T.; Macauley, J.M.; Summers, J.K.

1998-01-01

31

Quantitative PCR Enumeration of Total/Toxic Planktothrix rubescens and Total Cyanobacteria in Preserved DNA Isolated from Lake Sediments  

PubMed Central

The variability of spatial distribution and the determinism of cyanobacterial blooms, as well as their impact at the lake scale, are still not understood, partly due to the lack of long-term climatic and environmental monitoring data. The paucity of these data can be alleviated by the use of proxy data from high-resolution sampling of sediments. Coupling paleolimnological and molecular tools and using biomarkers such as preserved DNA are promising approaches, although they have not been performed often enough so far. In our study, a quantitative PCR (qPCR) technique was applied to enumerate total cyanobacterial and total and toxic Planktothrix communities in preserved DNA derived from sediments of three lakes located in the French Alps (Lake Geneva, Lake Bourget, and Lake Annecy), containing a wide range of cyanobacterial species. Preserved DNA from lake sediments was analyzed to assess its quality, quantity, and integrity, with further application for qPCR. We applied the qPCR assay to enumerate the total cyanobacterial community, and multiplex qPCR assays were applied to quantify total and microcystin-producing Planktothrix populations in a single reaction tube. These methods were optimized, calibrated, and applied to sediment samples, and the specificity and reproducibility of qPCR enumeration were tested. Accurate estimation of potential inhibition within sediment samples was performed to assess the sensitivity of such enumeration by qPCR. Some precautions needed for interpreting qPCR results in the context of paleolimnological approaches are discussed. We concluded that the qPCR assay can be used successfully for the analysis of lake sediments when DNA is well preserved in order to assess the presence and dominance of cyanobacterial and Planktothrix communities. PMID:21984244

Savichtcheva, Olga; Debroas, Didier; Kurmayer, Rainer; Villar, Clement; Jenny, Jean Philippe; Arnaud, Fabien; Perga, Marie Elodie; Domaizon, Isabelle

2011-01-01

32

Total mercury and methylmercury in sediments near offshore drilling sites in the Gulf of Mexico  

Microsoft Academic Search

Concentrations of total Hg in sediments near six drilling sites in the Gulf of Mexico were elevated well above average background\\u000a values of 40–80 ng\\/g. The excess Hg was associated with barite from discharged drilling mud. In contrast with total Hg, concentrations\\u000a of methylmercury (MeHg) in these sediments did not vary significantly at nearfield (3 km) distances\\u000a from the drilling sites. Observed

John H. Trefry; Robert P. Trocine; Michelle L. McElvaine; Robert D. Rember; Lucas T. Hawkins

2007-01-01

33

Total mercury and methylmercury in sediments near offshore drilling sites in the Gulf of Mexico  

Microsoft Academic Search

Concentrations of total Hg in sediments near six drilling sites in the Gulf of Mexico were elevated well above average background values of 40-80 ng\\/g. The excess Hg was associated with barite from discharged drilling mud. In contrast with total Hg, concentrations of methylmercury (MeHg) in these sediments did not vary significantly at nearfield (3 km) distances from the drilling

John H. Trefry; Robert P. Trocine; Michelle L. McElvaine; Robert D. Rember; Lucas T. Hawkins

2007-01-01

34

PCB CONGENERS AND HEXACHLOROBENZENE BIOTA SEDIMENT ACCUMULATING FACTORS FOR MACOMA NASUTA EXPOSED TO SEDIMENTS WITH DIFFERENT TOTAL ORGANIC CARBON CONTENTS  

EPA Science Inventory

Deposit-feeding marine clams (Macoma nasuta) were exposed for 119d to three sediment types that varied in total organic carbon (TOC) from 0.8 to 2.5%. ediments were spiked with equal concentrations of 13 polychlorinated biphenyl congeners and hexachlorobenzene. issue residues wer...

35

Annual replenishment of bed material by sediment transport in the Wind River near Riverton, Wyoming  

USGS Publications Warehouse

The U.S. Geological Survey, in cooperation with the Wyoming Department of Transportation, conducted a study during 1985-87 to determine the annual replenishment of sand and gravel along a point bar in the Wind River near Riverton, Wyoming. Hydraulic- geometry relations determined from streamflow measurements; streamflow characteristics determined from 45 years of record at the study site; and analyses of suspended-sediment, bedload, and bed- material samples were used to describe river transport characteristics and to estimate the annual replenishment of sand and gravel. The Wind River is a perennial, snowmelt-fed stream. Average daily discharge at the study site is about 734 cubic feet per second, and bankfull discharge (recurrence interval about 1.5 years) is about 5,000 cubic feet per second. At bankfull discharge, the river is about 136 feet wide and has an average depth of about 5.5 feet and average velocity of about 6.7 feet per second. Streams slope is about 0.0010 foot per foot. Bed material sampled on the point bar before the 1986 high flows ranged from sand to cobbles, with a median diameter of about 22 millimeters. Data for sediment samples collected during water year 1986 were used to develop regression equations between suspended-sediment load and water discharge and between bedload and water discharge. Average annual suspended-sediment load was computed to be about 561,000 tons per year using the regression equation in combination with flow-duration data. The regression equation for estimating bedload was not used; instead, average annual bedload was computed as 1.5 percent of average annual suspended load about 8,410 tons per year. This amount of bedload material is estimated to be in temporary storage along a reach containing seven riffles--a length of approximately 1 river mile. On the basis of bedload material sampled during the 1986 high flows, about 75 percent (by weight) is sand (2 millimeters in diameter or finer); median particle size is about 0.5 milli- meter. About 20 percent (by weight) is medium gravel to small cobbles--12.7 millimeters (0.5 inch) or coarser. The bedload moves slowly (about 0.03 percent of the water speed) and briefly (about 10 percent of the time). The average travel distance of a median-sized particle is about 1 river mile per year. The study results indicate that the average replenishment rate of bedload material coarser than 12.7 millimeters is about 1,500 to 2,000 tons (less than 1,500 cubic yards) per year. Finer material (0.075 to 6.4 millimeters in diameter) is replen- ishment at about 4,500 to 5,000 cubic yards per year. The total volume of potentially usable material would average about 6,000 cubic yards per year.

Smalley, M.L.; Emmett, W.W.; Wacker, A.M.

1994-01-01

36

Sediment concentration prediction and statistical evaluation for annual load estimation  

NASA Astrophysics Data System (ADS)

SummaryWe consider the development of statistical models for prediction of constituent concentration of riverine pollutants, which is a key step in load estimation from frequent flow rate data and less frequently collected concentration data. We consider how to capture the impacts of past flow patterns via the average discounted flow (ADF) which discounts the past flux based on the time lapsed - more recent fluxes are given more weight. However, the effectiveness of ADF depends critically on the choice of the discount factor which reflects the unknown environmental cumulating process of the concentration compounds. We propose to choose the discount factor by maximizing the adjusted R2 values or the Nash-Sutcliffe model efficiency coefficient. The R2 values are also adjusted to take account of the number of parameters in the model fit. The resulting optimal discount factor can be interpreted as a measure of constituent exhaustion rate during flood events. To evaluate the performance of the proposed regression estimators, we examine two different sampling scenarios by resampling fortnightly and opportunistically from two real daily datasets, which come from two United States Geological Survey (USGS) gaging stations located in Des Plaines River and Illinois River basin. The generalized rating-curve approach produces biased estimates of the total sediment loads by -30% to 83%, whereas the new approaches produce relatively much lower biases, ranging from -24% to 35%. This substantial improvement in the estimates of the total load is due to the fact that predictability of concentration is greatly improved by the additional predictors.

Wang, You-Gan; Tian, Ting

2013-03-01

37

Annual sediment flux estimates in a tidal strait using surrogate measurements  

NASA Astrophysics Data System (ADS)

Annual suspended-sediment flux estimates through Carquinez Strait (the seaward boundary of Suisun Bay, California) are provided based on surrogate measurements for advective, dispersive, and Stokes drift flux. The surrogates are landward watershed discharge, suspended-sediment concentration at one location in the Strait, and the longitudinal salinity gradient. The first two surrogates substitute for tidally averaged discharge and velocity-weighted suspended-sediment concentration in the Strait, thereby providing advective flux estimates, while Stokes drift is estimated with suspended-sediment concentration alone. Dispersive flux is estimated using the product of longitudinal salinity gradient and the root-mean-square value of velocity-weighted suspended-sediment concentration as an added surrogate variable. Cross-sectional measurements validated the use of surrogates during the monitoring period. During high freshwater flow advective and dispersive flux were in the seaward direction, while landward dispersive flux dominated and advective flux approached zero during low freshwater flow. Stokes drift flux was consistently in the landward direction. Wetter than average years led to net export from Suisun Bay, while dry years led to net sediment import. Relatively low watershed sediment fluxes to Suisun Bay contribute to net export during the wet season, while gravitational circulation in Carquinez Strait and higher suspended-sediment concentrations in San Pablo Bay (seaward end of Carquinez Strait) are responsible for the net import of sediment during the dry season. Annual predictions of suspended-sediment fluxes, using these methods, will allow for a sediment budget for Suisun Bay, which has implications for marsh restoration and nutrient/contaminant transport. These methods also provide a general framework for estimating sediment fluxes in estuarine environments, where temporal and spatial variability of transport are large.

Ganju, Neil K.; Schoellhamer, David H.

2006-08-01

38

Annual sediment flux estimates in a tidal strait using surrogate measurements  

USGS Publications Warehouse

Annual suspended-sediment flux estimates through Carquinez Strait (the seaward boundary of Suisun Bay, California) are provided based on surrogate measurements for advective, dispersive, and Stokes drift flux. The surrogates are landward watershed discharge, suspended-sediment concentration at one location in the Strait, and the longitudinal salinity gradient. The first two surrogates substitute for tidally averaged discharge and velocity-weighted suspended-sediment concentration in the Strait, thereby providing advective flux estimates, while Stokes drift is estimated with suspended-sediment concentration alone. Dispersive flux is estimated using the product of longitudinal salinity gradient and the root-mean-square value of velocity-weighted suspended-sediment concentration as an added surrogate variable. Cross-sectional measurements validated the use of surrogates during the monitoring period. During high freshwater flow advective and dispersive flux were in the seaward direction, while landward dispersive flux dominated and advective flux approached zero during low freshwater flow. Stokes drift flux was consistently in the landward direction. Wetter than average years led to net export from Suisun Bay, while dry years led to net sediment import. Relatively low watershed sediment fluxes to Suisun Bay contribute to net export during the wet season, while gravitational circulation in Carquinez Strait and higher suspended-sediment concentrations in San Pablo Bay (seaward end of Carquinez Strait) are responsible for the net import of sediment during the dry season. Annual predictions of suspended-sediment fluxes, using these methods, will allow for a sediment budget for Suisun Bay, which has implications for marsh restoration and nutrient/contaminant transport. These methods also provide a general framework for estimating sediment fluxes in estuarine environments, where temporal and spatial variability of transport are large. ?? 2006 Elsevier Ltd. All rights reserved.

Ganju, N.K.; Schoellhamer, D.H.

2006-01-01

39

29 CFR 779.253 - What is included in computing the total annual inflow volume.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false What is included in computing the total annual inflow volume. 779...Act § 779.253 What is included in computing the total annual inflow volume...storage and any other will be included in computing the $250,000. The dollar volume of...

2011-07-01

40

29 CFR 779.253 - What is included in computing the total annual inflow volume.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false What is included in computing the total annual inflow volume. 779...Act § 779.253 What is included in computing the total annual inflow volume...storage and any other will be included in computing the $250,000. The dollar volume of...

2010-07-01

41

Suspended-sediment concentrations, loads, total suspended solids, turbidity, and particle-size fractions for selected rivers in Minnesota, 2007 through 2011  

USGS Publications Warehouse

Sediment-laden rivers and streams pose substantial environmental and economic challenges. Excessive sediment transport in rivers causes problems for flood control, soil conservation, irrigation, aquatic health, and navigation, and transports harmful contaminants like organic chemicals and eutrophication-causing nutrients. In Minnesota, more than 5,800 miles of streams are identified as impaired by the Minnesota Pollution Control Agency (MPCA) due to elevated levels of suspended sediment. The U.S. Geological Survey, in cooperation with the MPCA, established a sediment monitoring network in 2007 and began systematic sampling of suspended-sediment concentrations (SSC), total suspended solids (TSS), and turbidity in rivers across Minnesota to improve the understanding of fluvial sediment transport relations. Suspended-sediment samples collected from 14 sites from 2007 through 2011 indicated that the Zumbro River at Kellogg in the driftless region of southeast Minnesota had the highest mean SSC of 226 milligrams per liter (mg/L) followed by the Minnesota River at Mankato with a mean SSC of 193 mg/L. During the 2011 spring runoff, the single highest SSC of 1,250 mg/L was measured at the Zumbro River. The lowest mean SSC of 21 mg/L was measured at Rice Creek in the northern Minneapolis- St. Paul metropolitan area. Total suspended solids (TSS) have been used as a measure of fluvial sediment by the MPCA since the early 1970s; however, TSS concentrations have been determined to underrepresent the amount of suspended sediment. Because of this, the MPCA was interested in quantifying the differences between SSC and TSS in different parts of the State. Comparisons between concurrently sampled SSC and TSS indicated significant differences at every site, with SSC on average two times larger than TSS concentrations. The largest percent difference between SSC and TSS was measured at the South Branch Buffalo River at Sabin, and the smallest difference was observed at the Des Moines River at Jackson. Regression analysis indicated that 7 out of 14 sites had poor or no relation between SSC and streamflow. Only two sites, the Knife River and the Wild Rice River at Twin Valley, had strong correlations between SSC and streamflow, with coefficient of determination (R2) values of 0.82 and 0.80, respectively. In contrast, turbidity had moderate to strong relations with SSC at 10 of 14 sites and was superior to streamflow for estimating SSC at all sites. These results indicate that turbidity may be beneficial as a surrogate for SSC in many of Minnesota’s rivers. Suspended-sediment loads and annual basin yields indicated that the Minnesota River had the largest average annual sediment load of 1.8 million tons per year and the largest mean annual sediment basin yield of 120 tons of sediment per year per square mile. Annual TSS loads were considerably lower than suspended-sediment loads. Overall, the largest suspended-sediment and TSS loads were transported during spring snowmelt runoff, although loads during the fall and summer seasons occasionally exceeded spring runoff at some sites. This study provided data from which to characterize suspended sediment across Minnesota’s diverse geographical settings. The data analysis improves understanding of sediment transport relations, provides information for improving sediment budgets, and documents baseline data to aid in understanding the effects of future land use/land cover on water quality. Additionally, the data provides insight from which to evaluate the effectiveness and efficiency of best management practices at the watershed scale.

Ellison, Christopher A.; Savage, Brett E.; Johnson, Gregory D.

2014-01-01

42

Investigation of Total and Methyl Mercury in Fish and Sediment of Lake Michigan  

EPA Science Inventory

Sediment cores and fish collected between 1994 and 1996 as part of the Lake Michigan Mass Balance Project were analyzed for total and methyl mercury. Results of the fish analyses are being used to describe total and methyl mercury concentrations in forage fish and lake trout, re...

43

Distribution of total mercury and methylmercury in lake sediments in Arctic Ny-Ålesund  

Microsoft Academic Search

The toxicities and bioavailabilities of total mercury (THg) and methylmercury (MeHg) in aquatic systems have made them the subjects of recent research. In this study, we collected a lake sediment core from Ny-Ålesund in Svalbard and analyzed the distributions of THg and MeHg in the sediments. The increased trend of THg was caused by anthropogenic contamination since the 14th century

Shan Jiang; Xiaodong Liu; Qianqian Chen

2011-01-01

44

Distribution of total and methyl mercury in sediments along Steamboat Creek (Nevada, USA)  

USGS Publications Warehouse

In the late 1800s, mills in the Washoe Lake area, Nevada, used elemental mercury to remove gold and silver from the ores of the Comstock deposit. Since that time, mercury contaminated waste has been distributed from Washoe Lake, down Steamboat Creek, and to the Truckee River. The creek has high mercury concentrations in both water and sediments, and continues to be a constant source of mercury to the Truckee River. The objective of this study was to determine concentrations of total and methyl mercury (MeHg) in surface sediments and characterize their spatial distribution in the Steamboat Creek watershed. Total mercury concentrations measured in channel and bank sediments did not decrease downstream, indicating that mercury contamination has been distributed along the creek's length. Total mercury concentrations in sediments (0.01-21.43 ??g/g) were one to two orders of magnitude higher than those in pristine systems. At 14 out of 17 sites, MeHg concentrations in streambank sediments were higher than the concentrations in the channel, suggesting that low banks with wet sediments might be important sites of mercury methylation in this system. Both pond/wetland and channel sites exhibited high potential for mercury methylation (6.4-30.0 ng g-1 day-1). Potential methylation rates were positively correlated with sulfate reduction rates, and decreased as a function of reduced sulfur and MeHg concentration in the sediments. Potential demethylation rate appeared not to be influenced by MeHg concentration, sulfur chemistry, DOC, sediment grain size or other parameters, and showed little variation across the sites (3.7-7.4 ng g-1 day-1). ?? 2003 Elsevier B.V. All rights reserved.

Stamenkovic, J.; Gustin, M.S.; Marvin-DiPasquale, M. C.; Thomas, B.A.; Agee, J.L.

2004-01-01

45

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

USGS Publications Warehouse

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.

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

2000-01-01

46

Effective Discharge and Annual Sediment Yield on Brazos River  

NASA Astrophysics Data System (ADS)

Geometry of an alluvial river alters dynamically over the time due to the sediment mobilization on the banks and bottom of the river channel in various flow rates. Many researchers tried to define a single representative discharge for these morphological processes such as "bank-full discharge", "effective discharge" and "channel forming discharge". Effective discharge is the flow rate in which, the most sediment load is being carried by water, in a long term period. This project is aimed to develop effective discharge estimates for six gaging stations along the Brazos River from Waco, TX to Rosharon, TX. The project was performed with cooperation of the In-stream Flow Team of the Texas Water Development Board (TWDB). Project objectives are listed as: 1) developing "Flow Duration Curves" for six stations based on mean-daily discharge by downloading the required, additional data from U.S Geological Survey website, 2) developing "Rating Curves" for six gaging stations after sampling and field measurements in three different flow conditions, 3) developing a smooth shaped "Sediment Yield Histogram" with a well distinguished peak as effective discharge. The effective discharge was calculated using two methods of manually and automatic bin selection. The automatic method is based on kernel density approximation. Cross-sectional geometry measurements, particle size distributions and water field samples were processed in the laboratory to obtain the suspended sediment concentration associated with flow rate. Rating curves showed acceptable trends, as the greater flow rate we experienced, the more sediment were carried by water.

Rouhnia, M.; Salehi, M.; Keyvani, A.; Ma, F.; Strom, K. B.; Raphelt, N.

2012-12-01

47

Distribution of total mercury and methylmercury in lake sediments in Arctic Ny-?lesund.  

PubMed

The toxicities and bioavailabilities of total mercury (THg) and methylmercury (MeHg) in aquatic systems have made them the subjects of recent research. In this study, we collected a lake sediment core from Ny-?lesund in Svalbard and analyzed the distributions of THg and MeHg in the sediments. The increased trend of THg was caused by anthropogenic contamination since the 14th century through long-range transportation, especially after the industrial era. However, the peak values of Hg in surface sediment samples could be explained by the increased algal scavenging process in recent decades. All the biogeochemical proxies (e.g., pigments and diatom biomass) revealed recent sharp increases in aquatic primary production due to the current climate warming. Rock-Eval analyses indicated that algal-derived organic matter took up a large portion, and quantitative calculation showed that 89.6-95.8% of the Hg in post-1950 could be explained by scavenging. The distribution of MeHg has a close relationship with total Hg and organic matter. The oxidation-reduction condition is one of the possible factors affecting the methylation rates in H2 lake sediments. Higher algal productivity and organic matter actually led to the increased trend of methylation in the uppermost sediment. This study supports some new key hypotheses on climate-driven factors affecting Hg and MeHg cycling in High Arctic lake sediments. PMID:21306754

Jiang, Shan; Liu, Xiaodong; Chen, Qianqian

2011-05-01

48

AMS radiocarbon dating of annually laminated sediments from lake Holzmaar, Germany  

Microsoft Academic Search

AMS radiocarbon ages have been determined on terrestrial macrofossils selected from the annually laminated sediments of lake Holzmaar (Germany). The radiocarbon chronology of this lake covers the last 12.6 ka. Comparison of the radiocarbon dated varve chronology with tree ring data shows that an additional 878 years have to be added to the varve chronology. The corrected 14C varve chronology

Irena Hajdas; Bernd Zolitschka; Susan D. Ivy-Ochs; Jürg Beer; Georges Bonani; Suzanne A. G. Leroy; Jörg W. Negendank; Matthias Ramrath; Martin Suter

1995-01-01

49

Land2Sea database of river drainage basin sizes, annual water discharges, and suspended sediment fluxes  

Microsoft Academic Search

The Land2Sea database contains data on the sizes of 1519 exorheic river drainage basins (79% of the exorheic land area), annual suspended sediment fluxes (593 rivers, 63% of the exorheic land area), and water discharges (1272 rivers, 76% of the exorheic land area) that have been compiled from a variety of sources. The database extends earlier compilations, such as GEMS\\/GLORI.

Bernhard Peucker-Ehrenbrink

2009-01-01

50

Distributions of total mercury and methylmercury in surface sediments and fishes in Lake Shihwa, Korea.  

PubMed

The concentrations of total mercury (THg) and methylmercury (MeHg) in the sediments of Lake Shihwa, an artificial salt lake in Korea located near two large industrial complexes, were determined to investigate the state of Hg contamination in the lake sediments and the effect of local Hg source. THg and MeHg concentrations in the sediments, monitored for 2 years, ranged from 0.02 to 0.28 microg g(-1) and sediments showed higher values near industrial complexes and in the central part of the lake. However, the correlations between Hg and environmental factors, such as organic material (OM) content, and acid volatile sulfide (AVS), were weak and did not clearly explain the variation in Hg distribution. The spatial distribution of sediment Hg and monthly precipitation data during the sampling period showed that the amount of runoff following rain events and water gate operation may be additional important factors regulating Hg level and distribution in lake sediments. The levels of THg in fish species in this lake ranged from 9.8 to 35 ng g(-1), suggesting that the bioavailability of sediment Hg in the lake may be low. Although the THg concentrations in Lake Shihwa sediment were lower than those in other foreign study sites, they were higher than in neighboring coastal regions, and are constantly increasing. This result indicates that the nearby industrial complexes may be the major source of Hg found in the sediments of Lake Shihwa. PMID:19945147

Oh, Sehee; Kim, Moon-Kyung; Yi, Seung-Muk; Zoh, Kyung-Duk

2010-02-01

51

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.  

PubMed

Total organic carbon (TOC) (in sediment) and dissolved organic matter (DOM) (in water column) play important roles in controlling the mercury sequestration process by the sediments from the central east coast of India. This toxic metal prefers to associate with finer size particles (silt and clay) of sediments. Increasing concentrations of DOM in overlying water column may increase complexation/reduction processes of Hg(2+) within the water column and decrease the process of Hg sequestration by sediments. However, high concentrations of DOM in water column may increase Hg sequestration process by sediments. PMID:24355570

Chakraborty, Parthasarathi; Sharma, Brijmohan; Babu, P V Raghunath; Yao, Koffi Marcellin; Jaychandran, Saranya

2014-02-15

52

15 CFR 303.3 - Determination of the total annual duty-exemption.  

Code of Federal Regulations, 2010 CFR

... INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE MISCELLANEOUS REGULATIONS WATCHES, WATCH MOVEMENTS AND JEWELRY PROGRAM Watches and Watch Movements § 303.3 Determination of the total annual duty-exemption....

2010-01-01

53

Pluri-annual sediment budget in a navigated river system: the Seine River (France).  

PubMed

This study aims at quantifying pluri-annual Total Suspended Matter (TSM) budgets, and notably the share of river navigation in total re-suspension at a long-term scale, in the Seine River along a 225 km stretch including the Paris area. Erosion is calculated based on the transport capacity concept with an additional term for the energy dissipated by river navigation. Erosion processes are fitted for the 2007-2011 period based on i) a hydrological typology of sedimentary processes and ii) a simultaneous calibration and retrospective validation procedure. The correlation between observed and simulated TSM concentrations is higher than 0.91 at all monitoring stations. A variographic analysis points out the possible sources of discrepancies between the variabilities of observed and simulated TSM concentrations at three time scales: sub-weekly, monthly and seasonally. Most of the error on the variability of simulated concentrations concerns sub-weekly variations and may be caused by boundary condition estimates rather than modeling of in-river processes. Once fitted, the model permits to quantify that only a small fraction of the TSM flux sediments onto the river bed (<0.3‰). The river navigation contributes significantly to TSM re-suspension in average (about 20%) and during low flow periods (over 50%). Given the significant impact that sedimentary processes can have on the water quality of rivers, these results highlight the importance of taking into account river navigation as a source of re-suspension, especially during low flow periods when biogeochemical processes are the most intense. PMID:25241208

Vilmin, Lauriane; Flipo, Nicolas; de Fouquet, Chantal; Poulin, Michel

2015-01-01

54

Distribution and possible sources of total mercury in sediments from the Newark Bay Estuary, New Jersey  

SciTech Connect

A screening survey conducted by investigators of total mercury (Hg) concentrations in freshwater fishes from New Jersey rivers and lakes revealed elevated concentrations (>0.5 mg/kg wet weight) in the edible tissues of several species. The highest Hg concentrations were measured in largemouth bass (Micropterus salmoides) and chain pickerel(Esox niger) from waterbodies in the northeastern portion of the state that are heavily affected by agriculture, industry, and urbanization, and in waterbodies throughout the state with low pH(>5.0). Similar results have been reported in saltwater fishes collected from the Raritan River, Passaic River, and Newark Bay. Mercury is among the most toxic of metals and one of the most persistent in sediments and organisms. This paper reports the results of total Hg analysis conducted on samples of surface and buried sediments from 72 cores collected from Newark Bay and its major tributaries between 1991 and 1993. 18 refs., 2 figs., 1 tab

Iannuzzi, T.J. [Hart Environmental Engineering Corp., Portland, ME (United States); Wenning, R.J. [Hart Environmental Engineering Corp., North Ryde (Australia)

1995-12-01

55

Identifying the annual signal in laminated clastic sediments from a Late Pleistocene lake succession  

NASA Astrophysics Data System (ADS)

A thick (>250m) succession of laminated lacustrine sediments at the Baumkirchen site in the Inn Valley (Austria) indicates the presence of a lake or series of lake phases existing during Marine Isotope Stage 3. The laminations are highly complex, entirely clastic, and vary considerably in thickness and internal structure. Despite high sedimentation rates of 5-6 cm per year indicated by radiocarbon and pollen data, there is no systematic macroscopic annual pattern in the laminations which could be used to develop a high-resolution (varve) chronology. Microscopic investigations of thin sections revealed sub-mm to cm-scale silt layers punctuated by very thin (0.25-2 mm) clay-rich layers spaced semi-regularly between 2 and 8 cm where present. The spacing and small grain size of these thin layers suggests a possible annual process responsible for their formation: rain-out of the fine suspended sediment from the water column during winter, when fluvial discharge into the lake was negligible and its surface was frozen. These potentially annual layers are not reliably identifiable macroscopically, however, analysis of X-ray fluorescence core scan data revealed the layers to be enriched in several heavy metals: most strongly in Zn but also in Pb, Cu and Ni. Possible carrier minerals of these heavy metals are currently being investigated. The radiocarbon chronology (in the short upper section where it is available) and heavy metal peak counting agree within error suggesting the heavy metal enriched clay-rich layers are mostly annual. Available X-ray fluorescence data for 150 m of the section suggest no significant long-term changes in annual layer spacing (i.e. sedimentation rate) from the 5-6 cm average indicated by the radiocarbon data, although there is a high degree of small-scale variation. Preliminary optically stimulated luminescence dates point to the presence of several hiatuses in this succession suggesting a fragmented record containing several lake periods of high sedimentation rates, rather than a continuous record. Local, annually resolved chronologies will open the door to perform high-resolution investigations into rates of change of climate proxies (pollen and biomarkers) across stadial-to-interstadial transitions.

Barrett, Samuel; Starnberger, Reinhard; Spötl, Christoph; Brauer, Achim; Dulski, Peter

2014-05-01

56

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

USGS Publications Warehouse

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)

Thompson, K.R.

1985-01-01

57

Total metal levels in crayfish Astacus leptodactylus (Eschscholtz, 1823), and surface sediments in Lake Terkos, Turkey.  

PubMed

The aim of this study was to determine the total metal accumulation (aluminium, copper, manganese, lead, cadmium and iron) in different organs and eggs of Astacus leptodactylus (Eschscholtz, 1823) and sediments total metal contents (aluminium, copper, manganese, lead, cadmium, iron, zinc, chromium, nickel) in Lake Terkos. Water and sediment samples were collected from two stations at two different depths (1 and 2 m) of Lake Terkos in May 2008. Crayfish samples were collected by trammel net at the same region. Primary hydrographic conditions, such as temperature (13.6-19.4 degrees C), salinity (0.27-0.34 per thousand), dissolved oxygen (7.04-12.30 mg l(-1)) and pH (7.42-8.51), were recorded for each sampling point. Moreover, the total organic carbon (1.65-5.44%) and the total calcium carbonate contents (19.44-41.16%) of sediment samples were determined. According to the Turkish Food Codex (J Zool 26:283-288, 2002), the maximum allowable Pb and Cd levels in crayfish are 0.5 mg/kg wet weight. Accordingly, the Pb and Cd levels determined in A. leptodactylus samples are below this limit. However, when compared with the acceptable metal limits defined by WHO, Australian National Health and Medical Research Council and Ministry of Agriculture in United Kingdom (UK), it is clear that the Cu level is at the limit and the Cd results exceed the limit. When the metal contents in sediment samples from Lake Terkos are examined, it is seen that the Al, Fe, Mn, Ni and Cu contents are lower while Zn, Cr, Cd and Pb contents are higher than the crustal average values. The high values draw attention to the land-based domestic and industrial inputs. Lake Terkos sediments have high enrichment factors (EF) of Zn, Cr, Cd and Pb metals which corroborate this result. The low EFs of Fe, Ni and Cu are due to the natural (terrigeneous) inputs. Additionally, there is no Al, Fe, Ni and Cu metal enrichment in these lake sediments because of the low contamination factor (CF) values. However, it is moderately contaminated by Zn, Cr and Pb, and heavily contaminated by Cd. PMID:19847663

Kurun, Aysegül; Balkis, Nuray; Erkan, Melike; Balkis, Hüsamettin; Aksu, Abdullah; Er?an, Mahmut Selim

2010-10-01

58

Comparability of suspended-sediment concentration and total suspended solids data  

USGS Publications Warehouse

Two laboratory analytical methods ? suspended-sediment concentration (SSC) and total suspended solids (TSS) ? are predominantly used to quantify concentrations of suspended solid-phase material in surface waters of the United States. The analytical methods differ. SSC data are produced by measuring the dry weight of all the sediment from a known volume of a water-sediment mixture. TSS data are produced by several methods, most of which entail measuring the dry weight of sediment from a known volume of a subsample of the original. An evaluation of 3,235 paired SSC and TSS data, of which 860 SSC values include percentages of sand-size material, shows bias in the relation between SSC and TSS ?SSC values tend to increase at a greater rate than their corresponding paired TSS values. As sand-size material in samples exceeds about a quarter of the sediment dry weight, SSC values tend to exceed their corresponding paired TSS values. TSS analyses of three sets of quality-control samples (35 samples) showed unexpectedly small sediment recoveries and relatively large variances in the TSS data. Two quality-control data sets (18 samples) that were analyzed for SSC showed both slightly deficient sediment recoveries, and variances that are characteristic of most other quality-control data compiled as part of the U.S. Geological Survey?s National Sediment Laboratory Quality Assurance Program. The method for determining TSS, which was originally designed for analyses of wastewater samples, is shown to be fundamentally unreliable for the analysis of natural-water samples. In contrast, the method for determining SSC produces relatively reliable results for samples of natural water, regardless of the amount or percentage of sand-size material in the samples. SSC and TSS data collected from natural water are not comparable and should not be used interchangeably. The accuracy and comparability of suspended solid-phase concentrations of the Nation?s natural waters would be greatly enhanced if all these data were produced by the SSC analytical method.

Gray, John R.; Glysson, G.D.; Turcios, L.M.; Schwarz, G.E.

2000-01-01

59

Statistical power of detecting trends in total suspended sediment loads to the Great Barrier Reef.  

PubMed

The export of pollutant loads from coastal catchments is of primary interest to natural resource management. For example, Reef Plan, a joint initiative by the Australian Government and the Queensland Government, has indicated that a 20% reduction in sediment is required by 2020. There is an obvious need to consider our ability to detect any trend if we are to set realistic targets or to reliably identify changes to catchment loads. We investigate the number of years of monitoring aquatic pollutant loads necessary to detect trends. Instead of modelling the trend in the annual loads directly, given their strong relationship to flow, we consider trends through the reduction in concentration for a given flow. Our simulations show very low power (<40%) of detecting changes of 20% over time periods of several decades, indicating that the chances of detecting trends of reasonable magnitudes over these time frames are very small. PMID:22551850

Darnell, Ross; Henderson, Brent; Kroon, Frederieke J; Kuhnert, Petra

2012-01-01

60

The relationship between total dissolved carbon dioxide and its stable carbon isotope ratio in aquatic sediments  

NASA Astrophysics Data System (ADS)

A model is constructed to predict the stable carbon isotope ratio of the total dissolved CO 2 in aquatic sediments and laboratory reactors. The major parameters of the model are the fractionation between CO 2 and CH 4 as well as the intra-molecular fractionation of acetate, the relative production of CH 4 from CO 2 reduction versus acetate fermentation, the net production ratio of CO 2 to CH 4 and the stable carbon isotope ratio of the source organic carbon. The model is fitted to published data and to date from the littoral sediments of Lake Memphremagog, Quebec, Canada. The inclusion of the intra-molecular fractionation factor of acetate in the model provides a good fit to the data; without this factor, the values of the other parameters necessary for a good fit appear unreasonable.

LaZerte, Bruce D.

1981-05-01

61

Total mercury in sediments and in Brazilian Ariidae catfish from two estuaries under different anthropogenic influence.  

PubMed

Santos-São Vicente estuary, located in São Paulo State, Brazil, has a history of contamination by inorganic chemicals such as mercury (Hg). In the 1980s the Cubatão was considered one of the most polluted sites in the world as a consequence of the intense industrial activities located in the city close to the estuary. To provide data and evaluate the local biota, total mercury (THg) contents were determined in sediments and in fish, Cathorops spixii, from different areas of the Santos-São Vicente estuary. For comparison, samples were also collected in a non-polluted system with similar hydrochemistry characteristics, the Cananeia estuary. The water characteristics and THg levels in sediment and fish samples confirmed a high human influence in the Santos-São Vicente estuary. The lowest THg values, observed in Cananeia, were evidence of low anthropogenic influence. High values observed in Santos-São Vicente show the necessity for a monitoring program. PMID:22030105

Azevedo, Juliana S; Braga, Elisabete S; Favaro, Deborah T; Perretti, Adriana R; Rezende, Carlos Eduardo; Souza, Cristina Maria M

2011-12-01

62

41033Federal Register / Vol. 78, No. 131 / Tuesday, July 9, 2013 / Notices Estimated Total Annual Burden  

E-print Network

to minimize the burden of the collection of information on respondents, including through the use of automated Burden Hours: 510. Estimated Total Annual Cost to Public: $20. IV. Request for Comments Comments of the agency's estimate of the burden (including hours and cost) of the proposed collection of information; (c

63

Adjustment of total suspended solids data for use in sediment studies  

USGS Publications Warehouse

The U.S. Environmental Protection Agency identifies fluvial sediment as the single most widespread pollutant in the Nation's rivers and streams, affecting aquatic habitat, drinking water treatment processes, and recreational uses of rivers, lakes, and estuaries. A significant amount of suspended-sediment data has been produced using the total suspended solids (TSS) laboratory analysis method. An evaluation of data collected and analyzed by the U.S. Geological Survey and others has shown that the variation in TSS analytical results is considerably larger than that for traditional suspended-sediment concentration analyses (SSC) and that the TSS data show a negative bias when compared to SSC data. This paper presents the initial results of a continuing investigation into the differences between TSS and SSC results. It explores possible relations between these differences and other hydrologic data collected at the same stations. A general equation was developed to relate TSS data to SSC data. However, this general equation is not applicable for data from individual stations. Based on these analyses, there appears to be no simple, straightforward way to relate TSS and SSC data unless pairs of TSS and SSC results are available for a station.

Glysson, G.D.; Gray, J.R.; Conge, L.M.

2000-01-01

64

Stability of the total and functional microbial communities in river sediment mesocosms exposed to anthropogenic disturbances.  

PubMed

River systems are exposed to anthropogenic disturbances, including chemical pollution and eutrophication. This may affect the phylogenetic diversity as well as the abundance of various functional groups within sediment-associated microbial communities. To address such potential effects, mesocosms filled with Ebro delta sediment covered with river water were exposed to chlorinated organic compounds or to a high nutrient concentration as used for fertilization. Changes in the abundance of selected functional microbial groups, i.e. total aerobes, nitrate, sulfate and iron reducers, organohalide-respiring microorganisms as well as methanogens, were examined using culture-dependent most probable number and culture-independent PCR methods targeting phylogenetic as well as functional gene markers. It was concluded that the abundance of functional groups was neither affected by pollution with 1,2-dichloroethane and tetrachloroethene nor by elevated nutrient loads, although changes in the bacterial community composition were observed using 16S rRNA gene-targeted fingerprint techniques. This study reinforced the notion that complementary culture-dependent and molecular methods, focusing on different fractions of the microbial community (cultivable, active or total), should be used in combination for a comprehensive description of phylogenetic diversity and functional potential. PMID:20618856

Van der Zaan, Bas; Smidt, Hauke; De Vos, Willem M; Rijnaarts, Huub; Gerritse, Jan

2010-10-01

65

Relations between total-sediment load and peak discharge for rainstorm runoff on five ephemeral streams in Wyoming  

USGS Publications Warehouse

Total-sediment loads transported by ephemeral flows are a function of rainstorm energy and peak discharge. Rainstorm energy, estimated by rainfall intensity, is the primary mechanism for soil-particle detachment. Vegetation, soil cohesiveness, and land slope also are related to the amount of sediment detached, but these factors remain nearly constant, except for seasonal or human-induced changes in vegetation. Thus, the largest variability in total-sediment loads is the result of variability in rainstorm energy. The magnitude of the peak discharge in a stream from a runoff-producing rainstorm is a function of the intensity and volume of rainfall. The greater the rainfall intensity for the same volume of rainfall, the larger the peak discharge. Therefore, for each drainage area a relation exists between the total-sediment load for a rainstorm and the peak discharge for the rainstorm, because both are a function of rainstorm energy. Total-sediment loads for runoff-producing rainstorms were computed from sample data collected at five ephemeral streams in semiarid areas of Wyoming. Regression analyses were used to develop equations relating total-sediment load to the peak discharge. Coefficients of determination ranged from 89 to 97 percent. Average standard errors ranged from 35 to 94 percent. The slopes of the lines defined by the equations were not different at the 95-percent level of significance, but the intercepts were significantly different for the five streams.

Rankl, J.G.

2004-01-01

66

Mean annual temperature and total annual precipitation trends at Canadian biosphere reserves.  

PubMed

This article examines instrumental climate records from a variety of stations associated with the following Biosphere Reserves across Canada: (i) Waterton Lakes, (ii) Riding Mountain, (iii) Niagara Escarpment, (iv) Long Point, and (v) Kejimkujik (Candidate Biosphere Reserve). Annual series are generated from daily temperature and precipitation values. In addition, homogeneous data are used from other stations and regional records to supplement the records from the local biosphere stations. Long term trends are identified over the period of the instrumental record. In general, data from the interval 1900 to 1998 show cooler temperatures in the 1920's, warming from the early 1940's into the early 1950's, cooling into the 1970's, and subsequent warming. At many stations, 1998 is the warmest in the instrumental record. Comparisons with the regional data sets show good agreements between the temperature series. The 20th century warming is approximately 1.0 degree C in the Riding Mountain area and 0.6 degrees C in the Long Point, Niagara Escarpment, and Waterton Lakes areas. There has been slight cooling in the Kejimkujik area over the past half century. Precipitation data show increasing trends in the Kejimkujik. Long Point, Niagara Escarpment, and Waterton Lakes areas with no long term trend in the Riding Mountain area. This work is part of the Canadian Biosphere Reserves Association (CBRA) Climate Change Initiative (CCI), designed to present climate change information to Biosphere Reserve communities to allow local organizations to understand climate change and adapt to potential impacts. PMID:11339701

Hamilton, J P; Whitelaw, G S; Fenech, A

2001-01-01

67

Total mercury concentration in sediment from the continental shelf of central California  

NASA Astrophysics Data System (ADS)

In order to understand the biogeochemical distribution of mercury (Hg) and locate specific Hg hot spots in the coastal region of central California, total mercury (HgT) concentration were measured in 43 archived sediment cores collected between Año Nuevo and the southern end of Monterey Bay. The samples were taken from USGS in Menlo Park, California on May 4th 2012. The cores were collected through the Environmental Management Assessment Program (EMAP), with ID sites: M-1-95-MB, P-2-95-MB and P-1-97-MB. For the purpose of this study we assumed that there has been negligible diagenesis on trace metal Hg since samples were taken. Total Hg concentrations were measured on the top five cm of the cores and yielded a mean of 0.037 ?g g-1, and ranged from 0.013 to 0.113 ?g g-1. In addition, the 43 samples were split into nine transects, and transects found near the mouth of Monterey Bay submarine canyon (MBSC) contained the highest concentration of HgT, with a mean concentration of 0.043 ?g g-1, and ranged from 0.038 to 0.113 ?g g-1. This substantial increase in HgT concentration near MBSC might be a product of the bathymetry acting as a sink or interaction between internal waves and the canyon's rim. This allows reactivation of surface sediment, which can separate fine grained sand, mud and clay content near the mid-shelf region and the canyon rim. Three depth profiles with 0-30 cm intervals were measured for HgT concentrations. Cores averaged mean HgT concentrations of 0.032, 0.040, and 0.037 ?g g-1, while each profile ranged from 0.025-0.043, 0.028-0.065 and 0.022-0.051 ?g g-1. Each depth profile had slight variations in HgT concentrations. One core located between Daven Port and Santa Cruz displayed decreasing HgT concentration with increasing depth. The inconsistency seen in the depth profiles might be products of external factors such as textural changes as depth increases, changes in Hg fluxes, bio mixing, and diagenesis such as redox reactions. Furthermore, comparisons of our data with sedimentation rates found in Monterey Bay have shown mercury concentration in the sediment not influenced by sedimentation rates. Instead, we observed decrease in mud content corresponded to decrease in HgT concentrations; perhaps supporting Hg's strong correlation to organic matter. Although, the sediment Hg concentration in the coastal regions of Monterey Bay, was substantially lower than those found in San Francisco Bay, the data found in this study is conclusive that the hot spots found near MBSC could be an overlooked source of Hg in coastal environments and needs further investigation.

Acosta, R. M.; Weiss-Penzias, P. S.; Bauer, V.; Ryan, J. P.; Flegal, A. R.

2012-12-01

68

Spatiotemporal climatic, hydrological, and environmental variations based on records of annually laminated lake sediments from northern Poland  

Microsoft Academic Search

In northern Poland there is the unique opportunity to compare varved lake sediment records with distinct climatic trends along a 700 km long W-E transect. Annually laminated Holocene sediment sequences from Lake Lubinskie, Lake Suminko, Lake Lazduny, and Lake Szurpily were cored for high-resolution multiproxy climate and environmental reconstruction in the framework of the Polish-German project ``Northern Polish Lake Research''

W. Tylmann; L. Blanke; M. Kinder; T. Loewe; C. Mayr; C. Ohlendorf; B. Zolitschka

2009-01-01

69

Ratios of total suspended solids to suspended sediment concentrations by particle size  

USGS Publications Warehouse

Wet-sieving sand-sized particles from a whole storm-water sample before splitting the sample into laboratory-prepared containers can reduce bias and improve the precision of suspended-sediment concentrations (SSC). Wet-sieving, however, may alter concentrations of total suspended solids (TSS) because the analytical method used to determine TSS may not have included the sediment retained on the sieves. Measuring TSS is still commonly used by environmental managers as a regulatory metric for solids in storm water. For this reason, a new method of correlating concentrations of TSS and SSC by particle size was used to develop a series of correction factors for SSC as a means to estimate TSS. In general, differences between TSS and SSC increased with greater particle size and higher sand content. Median correction factors to SSC ranged from 0.29 for particles larger than 500m to 0.85 for particles measuring from 32 to 63m. Great variability was observed in each fraction-a result of varying amounts of organic matter in the samples. Wide variability in organic content could reduce the transferability of the correction factors. ?? 2011 American Society of Civil Engineers.

Selbig, W.R.; Bannerman, R.T.

2011-01-01

70

Total mercury in sediments, macrophytes, and fish from a shallow steppe lake in eastern Austria.  

PubMed

During summer 2011, samples of sediment, macrophytes, and fish tissues from the shallow, slightly alkaline Lake Neusiedl, Austria, were evaluated for their total Hg content. This is the first report of Hg levels from this lake. Sediments displayed Hg contents between 0.025 and 0.113 ?g g(-1) dw (dry weight), significantly correlating with the proportion of organic components pointing to a small anthropogenic impact on the lake's Hg content. Hg Levels in plants and fish were unexpectedly high: both investigated submerged plant species, Potamogeton pectinatus and Myriophyllum spicatum, showed mean values of 0.245 ± 0.152 and 0.298 ± 0.115 ?g g(-1) dw, respectively. Biomagnification was evident when comparing muscle samples of the planktivorous fish species rudd Scardinus erythrophthalmus (n = 10, mean = 0.084 ?g g(-1) ww (wet weight)) with the piscivorous perch Perca fluviatilis (n = 21, mean = 0.184 ?g g(-1) ww) or pike-perch Sander lucioperca (n = 9, mean = 0.205 ?g g(-1) ww). Significantly lower values were found in the muscle of the piscivorous pike Esox lucius (n = 25, mean = 0.135 ?g g(-1) ww), pointing to a specific Hg metabolism of this fish, presumably under the particular physicochemical properties of the lake. Hg Concentrations in fish could pose a risk to piscivorous birds in this protected wetland system. PMID:25146770

Jirsa, Franz; Pirker, Daniel; Krachler, Regina; Keppler, Bernhard K

2014-08-01

71

Features of annual and semiannual variations derived from the global ionospheric maps of total electron content  

Microsoft Academic Search

In the present work we use the NASA-JPL global ionospheric maps of total electron content (TEC), firstly to construct TEC maps (TEC vs. magnetic local time MLT, and magnetic latitude MLAT) in the interval from 1999 to 2005. These TEC maps were, in turn, used to estimate the annual-to-mean amplitude ratio, A1, and the semiannual-to-mean amplitude ratio, A2, as well

B. Zhao; W. Wan; L. Liu; T. Mao; Z. Ren; M. Wang; A. B. Christensen

2007-01-01

72

Statistic analysis of annual total ozone extremes for the period 1964-1988  

NASA Technical Reports Server (NTRS)

Annual extremes of total column amount of ozone (in the period 1964-1988) from a network of 29 Dobson stations have been examined using the extreme value analysis. The extremes have been calculated as the highest deviation of daily mean total ozone from its long-term monthly mean, normalized by the monthly standard deviations. The extremes have been selected from the direct-Sun total ozone observations only. The extremes resulting from abrupt changes in ozone (day to day changes greater than 20 percent) have not been considered. The ordered extremes (maxima in ascending way, minima in descending way) have been fitted to one of three forms of the Fisher-Tippet extreme value distribution by the nonlinear least square method (Levenberg-Marguard method). We have found that the ordered extremes from a majority of Dobson stations lie close to Fisher-Tippet type III. The extreme value analysis of the composite annual extremes (combined from averages of the annual extremes selected at individual stations) has shown that the composite maxima are fitted by the Fisher-Tippet type III and the composite minima by the Fisher-Tippet type I. The difference between the Fisher-Tippet types of the composite extremes seems to be related to the ozone downward trend. Extreme value prognoses for the period 1964-2014 (derived from the data taken at: all analyzed stations, the North American, and the European stations) have revealed that the prognostic extremes are close to the largest annual extremes in the period 1964-1988 and there are only small regional differences in the prognoses.

Krzyscin, Janusz W.

1994-01-01

73

Vertical distribution of total mercury and methylmercury in sediment of the Fugong mangrove area at Jiulong River Estuary, Fujian, China.  

PubMed

The concentrations and vertical distributions of total mercury (Hg) and methylmercury (methyl Hg) in the sediment of the Fugong mangrove area, located at the Jiulong River Estuary, Fujian, China, were investigated. The concentrations of total mercury were between 0.12-0.17 and 0.11-40.14 microg/g, while concentrations of methylmercury were between 0.15-1.8 and 0.081-0.58 ng/g (as mercury), in the dry and rainy seasons, respectively. The total mercury concentration was not correlated with the sampling depth. As the depth increased, methylmercury concentrations first increased to their maximum level at a depth of 10-25 cm, and then decreased; this was similar to the vertical distribution characteristics of methylmercury/total mercury ratios. The mangrove ecosystem was considered as a source of methylmercury for adjacent areas, due to the higher average methylmercury concentration in the mangrove sediment than other sediments nearby. Statistically significant logarithmic correlations, conic correlations, and negative correlations were observed for methylmercury and sulfide concentration, sediment organic matter, and sediment pH, respectively. PMID:23833815

Liang, Ying; Yuan, Dongxing; Chen, Yaojin; Liu, Xiyao

2013-06-01

74

Total Sediment Load from SEMEP Using Depth-Integrated Concentration Measurements  

E-print Network

the median particle size measured in suspension d50ss. On the basis of the sediment discharge measurements collected from 14 rivers, the accuracy of sediment discharge calculations depend on the ratio of the shear on the basis of bed sediment discharge is recommended when uÃ?=

Julien, Pierre Y.

75

Distribution and statistical analysis of leachable and total heavy metals in the sediments of the Suez Gulf.  

PubMed

The concentrations of nine heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pd and Zn) in the labile and total fractions of muddy and sandy sediment samples collected from twelve sites in Suez Gulf during April 1999 were studied to evaluate the pollution status of the Suez Gulf. The enrichment factors (EF) for each element were calculated. There are extremely high concentrations of Cd, Ni, Pb and slightly concentration of Cr and Cu in both muddy and sandy sediments. The concentration of Zn was moderately high and can be considered as seriously contaminate Metal pollution index (MPI) shows high values ranged between 46 to 156 and 40 to 232 for both sandy and muddy sediments, respectively. Concentrations of heavy metals were normalized against iron for total fraction in both of sandy and muddy sediments. Principal component analysis (PCA) was studied on the data matrix obtained and represented three-factor model explaining 92.22% for labile and 88.82% for total fractions of muddy sediment. The main source of contamination is the offshore oil fields and industrial wastes. This is largely a result of ineffective and inefficient operation equipment, illegal discharge of dirty ballast water from tankers and lack of supervision and prosecution of offenders. PMID:16897536

el-Nemr, Ahmed; Khaled, Azza; el-Sikaily, Amany

2006-07-01

76

Comparisons between thorium isotopes in seawater and marine sediments for reconstructing dissolved and total detrital inputs to the ocean  

NASA Astrophysics Data System (ADS)

Thorium-232, the most abundant Th isotope in the continental crust, has been widely used in seawater and marine sediments to evaluate continental inputs to the ocean. Seawater 232Th concentrations combined with estimates of Th residence time in the surface ocean derived from measurements of 230Th (or 234Th or 228Th) have been used to assess the dissolved 232Th removal flux. Assuming a constant 232Th concentration in detritus and dust Th solubility in seawater, 232Th removal flux can be converted to atmospheric dust input to the ocean. In marine sediments, 232Th concentrations have been normalized by 230Th to estimate total 232Th sinking flux to the seafloor. Similarly, this flux can also be used to estimate dust input to the ocean. Comparisons between dissolved 232Th removal flux in seawater and total 232Th sinking flux in sediments are crucial, because the discrepancy between these two fluxes could provide insights into several important issues, including uncertain dust Th solubility, potential advective Th inputs, inaccurate 230Th-derived sediment accumulation rates, and unknown lateral sediment transport. However, comparisons between these two fluxes have rarely been made in the same core-top sediments and water columns above. In this study, we compile several seawater and marine sediment Th data from different regions of the ocean, with a focus on the tropical North Atlantic Ocean. The data are used to estimate 232Th removal and sinking fluxes, and hence the dissolved and total detrital inputs to the ocean. The results are also compared with other dust tracers (e.g. Al and Ti) and modeled dust deposition to improve our understanding of Th and dust in the ocean. This work offers an important test for the use of Th isotopes in reconstructing paleo dust input to the ocean and the impacts of dust flux changes on marine productivity and climate change in the past.

Hsieh, Y.; Henderson, G. M.; Williams, R. H.; McGee, D.

2012-12-01

77

12 CFR Appendix K to Part 226 - Total Annual Loan Cost Rate Computations for Reverse Mortgage Transactions  

Code of Federal Regulations, 2013 CFR

...Cost Rate Computations for Reverse Mortgage Transactions K Appendix K to Part 226 Banks and Banking FEDERAL RESERVE SYSTEM... TRUTH IN LENDING (REGULATION Z) Pt. 226, App. K Appendix K to Part 226—Total Annual Loan Cost...

2013-01-01

78

12 CFR Appendix K to Part 226 - Total Annual Loan Cost Rate Computations for Reverse Mortgage Transactions  

Code of Federal Regulations, 2012 CFR

...Cost Rate Computations for Reverse Mortgage Transactions K Appendix K to Part 226 Banks and Banking FEDERAL RESERVE SYSTEM...SYSTEM TRUTH IN LENDING (REGULATION Z) Pt. 226, App. K Appendix K to Part 226—Total Annual Loan Cost...

2012-01-01

79

12 CFR Appendix K to Part 1026 - Total Annual Loan Cost Rate Computations for Reverse Mortgage Transactions  

Code of Federal Regulations, 2012 CFR

...Cost Rate Computations for Reverse Mortgage Transactions K Appendix K to Part 1026 Banks and Banking BUREAU OF CONSUMER FINANCIAL... TRUTH IN LENDING (REGULATION Z) Pt. 1026, App. K Appendix K to Part 1026—Total Annual Loan Cost...

2012-01-01

80

12 CFR Appendix K to Part 1026 - Total Annual Loan Cost Rate Computations for Reverse Mortgage Transactions  

Code of Federal Regulations, 2013 CFR

...Cost Rate Computations for Reverse Mortgage Transactions K Appendix K to Part 1026 Banks and Banking BUREAU OF CONSUMER FINANCIAL... TRUTH IN LENDING (REGULATION Z) Pt. 1026, App. K Appendix K to Part 1026—Total Annual Loan Cost...

2013-01-01

81

12 CFR Appendix K to Part 226 - Total Annual Loan Cost Rate Computations for Reverse Mortgage Transactions  

Code of Federal Regulations, 2014 CFR

...Cost Rate Computations for Reverse Mortgage Transactions K Appendix K to Part 226 Banks and Banking FEDERAL RESERVE SYSTEM... TRUTH IN LENDING (REGULATION Z) Pt. 226, App. K Appendix K to Part 226—Total Annual Loan Cost...

2014-01-01

82

Variation and distribution of total mercury in water, sediment and soil from northern Lake Victoria, East Africa  

Microsoft Academic Search

Lake Victoria, the world's largest tropical freshwater lake, is an important resource, ecologi- cally and economically. THg distribution in the northern parts of the lake are not well known, so to answer this gap, patterns in total mercury (THg) in water, soil and two dated sediment cores from north- ern Lake Victoria were determined. Water THg concentrations ranged from 0.7

L. M. CAMPBELL; R. E. HECKY; R. MUGGIDE; D. G. DIXON

2003-01-01

83

Variation and distribution of total mercury in water, sediment and soil from northern Lake Victoria, East Africa  

Microsoft Academic Search

Lake Victoria, the world's largest tropical freshwater lake, is an important resource, ecologically and economically. THg distribution in the northern parts of the lake are not well known, so to answer this gap, patterns in total mercury (THg) in water, soil and two dated sediment cores from northern Lake Victoria were determined. Water THg concentrations ranged from 0.7 to 5.8

L. M. Campbell; R. E. Hecky; R. Muggide; D. G. Dixon; P. S. Ramlal

2003-01-01

84

METHODS FOR THE DETERMINATION OF TOTAL ORGANIC CARBON (TOC) IN SOILS AND SEDIMENTS  

EPA Science Inventory

Organic matter in soils and sediments is widely distributed over the earth's surface occurring in almost all terrestrial and aquatic environments (Schnitzer, 1978). Soils and sediments contain a large variety of organic materials ranging from simple sugars and carbohydrates to th...

85

Microscopic observation of laminated sediment in thin section using diatom assemblages to reconstruct annual paleoenvironmental changes  

NASA Astrophysics Data System (ADS)

Eastern Hokkaido is a severe earthquake and tsunami district. Lake Harutori, located in eastern Hokkaido, records 22 traces of huge tsunamis in lake sediment since 9500 years ago. The latest event was occurred in 17th century (e.g. Nanayama et al., 2003). However, the strict age is still unknown, because the autochthon Ainu culture did not have literature. In lake sediment, there is laminated structure between tsunami deposits, and also on the 17th huge tsunami deposit. If this laminated structure was recognized as annual varve, it will be able to decide the strict age and reconstruct the paleoenvironment in high resolution. Large thin section 165 mm length was made included 17th tsunami deposits, laminated silt layer and age known tephra and observed lithofacies and diatoms with 1,000 magnification light microscope. The thin section comprised from 80 mm thick tsunami deposit in bottom, 60 mm thick laminated silt layer, 15 mm tephra as known as Ta-b fallen in 1667A.D. and 10 mm laminated silt layer at the top. As the result of optical observation to laminated silt layer, 31 laminated structures were recognized. Inferred from diatom assemblages, 37 cyclic productions were recognized. Diatom components were apparently changed from bottom to top and were seemed to influence by the changes of lake water conditions after tsunami inundation. These results indicate that the start of accumulation of laminated silt layer and/or the end of confusion of lake water by tsunami current was around 1630 A.D.; 37 years before 1667 A.D.. This earthquake was separated from the 1611 Keicho Sanriku earthquake was well known in this era and the hypocenters of these earthquakes need to reexam.

Ishikawa, S.; Kaoru, K.

2013-12-01

86

Measuring total longshore sediment transport with a LISST instrumented mini-sled.  

E-print Network

A surf zone sediment transport study was conducted in Jamaica Beach, Texas, using new oceanographic equipment. A mini-sled was constructed and outfitted with an instrument package that consisted of two velocimeters, one current profiler, three OBS...

Huchzermeyer, Erick Karl

2006-04-12

87

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

NASA Astrophysics Data System (ADS)

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.

Wobbe, Florian; Lindeque, Ansa; Gohl, Karsten

2014-12-01

88

University Sustem of Ohio (USO) Measures Department/School Availability 0. Total Degrees / Certificates Awarded (Annual) from IR  

E-print Network

/ Certificates Awarded (Annual) from IR At Least One- but Less than Two-Year Certificates from IR Associate from IR Bachelor's from IR Master's from IR Doctoral from IR 1a. Total post-secondary enrollment (Fall) from IR 1b. Underrgraduate enrollment (Fall) from IR 1c. Graduate enrollment (Fall) from IR 2. Total

Moore, Paul A.

89

Suspended-sediment and suspended-sand concentrations and loads for selected streams in the Mississippi River Basin, 1940-2009  

USGS Publications Warehouse

This report presents suspended-sediment concentration and streamflow data, describes load-estimation techniques used in the computation of annual suspended-sediment loads, and presents annual suspended-sediment loads for 48 streamgaging stations within the Mississippi River Basin. Available published, unpublished, and computed annual total suspended-sediment and suspended-sand loads are presented for water years 1940 through 2009. When previously published annual loads were not available, total suspended-sediment and sand loads were computed using available data for water years 1949 through 2009. A table of suspended-sediment concentration and daily mean streamflow data used in the computation of annual loads is presented along with a table of compiled and computed annual suspended-sediment and suspended-sand loads, annual streamflows, and flow-weighted concentrations for the 48 stations.

Heimann, David C.; Cline, Teri L.; Glaspie, Lori M.

2011-01-01

90

Comparability of suspended-sediment concentration and total suspended-solids data for two sites on the L'Anguille River, Arkansas, 2001 to 2003  

USGS Publications Warehouse

Suspended-sediment concentration and total suspended solids data collected with automatic pumping samplers at the L'Anguille River near Colt and the L'Anguille River at Palestine, Arkansas, August 2001 to October 2003 were compared using ordinary least squares regression analyses to determine the relation between the two datasets for each of the two sites. The purpose of this report is to describe the suspended-sediment concentration and total suspended-solids data and examine the comparability of the two datasets for each site. Suspended-sediment concentration and total suspended solids data for the L'Anguille River varied spatially and temporally from August 2001 to October 2003. The site at the L'Anguille River at Palestine represents a larger portion of the L'Anguille River Basin than the site near Colt, and generally had higher median suspended-sediment concentration and total suspended solids and greater ranges in values. The differences between suspended-sediment concentration and total suspended solids data for the L'Anguille River near Colt appeared inversely related to streamflow and not related to time. The relation between suspended-sediment concentration and total suspended solids at the L'Anguille River at Palestine was more variable than at Colt and did not appear to have a relation with flow or time. The relation between suspended-sediment concentration and total suspended solids for the L'Anguille River near Colt shows that total suspended solids increased proportionally as suspended-sediment concentration increased. However, the relation between suspended-sediment concentration and total suspended solids for the L'Anguille River at Palestine showed total suspended solids increased less proportionally as suspended-sediment concentration increased compared to the L'Anguille River near Colt. Differences between the two analytical methods may partially explain differences between the suspended-sediment concentration and total suspended solids data at the two sites. Total suspended solids are analyzed by removing an aliquot of the original sample for further analysis, and suspended-sediment concentrations are analyzed using all sediment and the total mass of the sample. At the L'Anguille River at Palestine another source of variability in the two data sets could have been the location of the automatic pumping sampler intake. The intake was located at a point in the stream cross-section that was subject to sedimentation, which may have resulted in positive sample bias.

Galloway, Joel M.; Evans, Dennis A.; Green, W. Reed

2005-01-01

91

Total Mercury, Methylmercury, Methylmercury Production Potential, and Ancillary Streambed-Sediment and Pore-  

E-print Network

Total Mercury, Methylmercury, Methylmercury Production Potential, and Ancillary Streambed Oak Creek, Wisconsin (center). (All photographs by the authors.) #12;Total Mercury, Methylmercury.E., 2008, Total mercury, methylmercury, methylmercury production potential, and ancillary streambed

92

Monitoring Fine Sediment; Grande Ronde and John Day Rivers, 1999 Annual Report.  

SciTech Connect

This project was initiated to monitor surface fine sediment levels and overwinter intrusion of fine sediment in spring chinook salmon spawning habitat in the North Folk John Day and Grande Ronde Rivers, for five years.

Rhodes, Jonathan J.; Greene, M. Jonas; Purser, Michael D. (Columbia River Inter-Tribal Fish Commission, Portland, OR)

2000-01-01

93

Estimation of suspended-sediment concentration from total suspended solids and turbidity data for Kentucky, 1978-1995  

USGS Publications Warehouse

Suspended sediment is a constituent of water quality that is monitored because of concerns about accelerated erosion, nonpoint contamination of water resources, and degradation of aquatic environments. In order to quantify the relationship among different sediment parameters for Kentucky streams, long-term records were obtained from the National Water Information System of the U.S. Geological Survey. Suspended-sediment concentration (SSC), the parameter traditionally measured and reported by the U.S. Geological Survey, was statistically compared to turbidity and total suspended solids (TSS), two parameters that are considered surrogate data. A linear regression of log-transformed observations was used to estimate SSC from TSS; 72% of TSS observations were less than coincident SSC observations; however, the estimated SSC values were almost as likely to be overestimated as underestimated. The SSC-turbidity relationship also used log-transformed observations, but required a nonlinear, breakpoint regression that separated turbidity observations ???6nephelometric turbidity units. The slope for these low turbidity values was not significantly different than zero, indicating that low turbidity observations provide no real information about SSC; in the case of the Kentucky sediment record, this accounts for 30% of the turbidity observations. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

Williamson, T.N.; Crawford, C.G.

2011-01-01

94

NUTRIENT AND SEDIMENT TOTAL MAXIMUM DAILY LOADS FOR FIVE NORTH DAKOTA RESERVOIRS  

EPA Science Inventory

Five North Dakota reservoirs will be target for the development of a sediment nutrient TMDL. For each TMDL, a project specific QAPP will be developed. As part of each TMDL, field sampling will include tributary discharge and chemical sampling, lake sampling, and the development...

95

Differentiation between bioavailable and total hazard potential of sediment-induced DNA fragmentation as measured by the comet assay with Zebrafish embryos  

Microsoft Academic Search

Goals, Scope and Background  While water quality strongly improved over decades in the Rhine River, sediments still reflect elapsed contaminations of organic\\u000a pollutants and heavy metals. In comparing genotoxic effects induced by both sediment extracts and whole sediments, a ratio\\u000a of bioavailable toxicity and total extractable toxicity is obtained. Since contaminated sites whose contaminants are toxic\\u000a and as well bioavailable present

Thomas Kosmehl; Falk Krebs; Werner Manz; Thomas Braunbeck; Henner Hollert

2007-01-01

96

An evaluation of 14C age relationships between co-occurring foraminifera, alkenones, and total organic carbon in continental margin sediments  

Microsoft Academic Search

Radiocarbon age relationships between co-occurring planktic foraminifera, alkenones, and total organic carbon in sediments from the continental margins of southern Chile, northwest Africa, and the South China Sea were compared with published results from the Namibian margin. Age relationships between the sediment components are site-specific and relatively constant over time. Similar to the Namibian slope, where alkenones have been reported

Gesine Mollenhauer; Markus Kienast; Frank Lamy; Helge Meggers; Ralph R. Schneider; John M. Hayes; Timothy I. Eglinton

2005-01-01

97

Monitoring Fine Sediment; Grande Ronde and John Day Rivers, 2000 Annual Report.  

SciTech Connect

Fine sediment in spawning substrate has a major effect on salmon survival from egg to smolt. Basin-wide restoration plans have established targets for fine sediment levels in spawning habitat. The project was initiated to monitor surface fine sediment levels and overwinter intrusion of fine sediment in spring chinook salmon spawning habitat in the North Fork John Day (NFJDR) and Grande Ronde Rivers, for five years. The project is also investigating the potential relationship between surface fine levels and overwinter sedimentation. It will provide data to assess trends in substrate conditions in monitored reaches and whether trends are consistent with efforts to improve salmon habitat conditions. The data on the magnitude of overwinter sedimentation will also be used to estimate salmon survival from egg to emergence. In Sept. 1998, 1999, and Aug. 2000, sites for monitoring overwinter sedimentation were established in salmon spawning habitat in the upper Grande Ronde River, Catherine Creek (a Grande Ronde tributary), the North Fork John Day River (NFJDR), and Granite Creek (a NFJDR tributary). Surface fine sediment levels were measured in these reaches via the grid method and visually estimated to test the relative accuracy of these two methods. In 1999 and 2000, surface fine sediment was also estimated via pebble counts at selected reaches to allow comparison of results among the methods. Overwintering substrate samples were collected in April 1999 and April-May 2000 to estimate the amount of overwinter sedimentation in clean gravels in spawning habitat. Monitoring methods and locations are described.

Rhodes, Jonathan J.; Greene, M. Jonas; Purser, Michael D. (Columbia River Inter-Tribal Fish Commission, Portland, OR)

2001-01-01

98

$8.6 billion The U of M creates $8.6 billion in total economic impact annually.  

E-print Network

$8.6 billion The U of M creates $8.6 billion in total economic impact annually. · $4.1 billion for goods and services purchased by the U of M, its employees, students, and visitors · $4.5 billion in spending by the businesses that provide those goods and services $13.20Every dollar invested in the U of M

Minnesota, University of

99

Suspended sediment and sediment-source areas in the Fountain Creek drainage basin upstream from Widefield, southeastern Colorado  

USGS Publications Warehouse

Suspended-sediment samples were collected from synoptic-sampling sites to determine suspended-sediment concentrations, loads, yields, and sediment-source areas in the Fountain Creek drainage basin upstream from Widefield, Colorado. Suspended-sediment yields ranged from 0.004 to 278 tons/sq mi/day. Twenty-four sites were sampled that represent urban and rural land use. The median suspended-sediment yield from urban drainage basins was 7.7 tons/sq mi/day and the median suspended-sediment yield from rural drainage basins was 0.46 ton/sq mi/day. Sediment-transport equations were derived for total suspended-sediment discharge and suspended-sand discharge at seven periodic-sampling sites. Annual suspended-sediment loads and yields were computed for the 1985 water year. Urbanization in the downstream parts of the Monument Creek drainage basin, the main tributary to Fountain Creek, affected sediment loads. The downstream 14% of the Monument Creek drainage basin contributed about 61% of the annual suspended-sediment load transported at the mouth of Monument Creek. About 73% of the annual suspended-sediment load for Fountain Creek at Colorado Springs was contributed by Monument Creek. Abandoned mill tailings along Fountain Creek contributed little to total suspended sediment load. Contributions of streambank erosion to basin sediment yields were not quantified. However, the measured rate of streambank erosion at a site on Fountain Creek has increased during a 37-year period. (USGS)

Von Guerard, Paul

1989-01-01

100

A semi-analytical total suspended sediment retrieval model in turbid coastal waters: a case study in Changjiang River Estuary.  

PubMed

A simple semi-analytical model to estimate total suspended sediment matter (3S) was established for estimating TSM concentrations in Changjiang River Estuary. The results indicate that 3S model with near-infrared wavelengths provide good estimates of TSM concentrations in the study region. Furthermore, the applicability of 3S model was evaluated using an independent data set taken from Oujiang river estuary during September 2012. The results indicate that providing an available atmospheric correction scheme for satellite imagery, the 3S model could be used for quantitative monitoring of TSM concentration in coastal waters, even though local bio-optical information is still needed to reinitialize the model. PMID:23736555

Chen, Jun; D'Sa, Eurico; Cui, Tingwei; Zhang, Xunhua

2013-06-01

101

A 450 year history of extreme floods in annually laminated sediment from pre-alpine Lake Ammersee (Southern Germany)  

NASA Astrophysics Data System (ADS)

Forecasting of extreme events and their impacts on the human habitat requires comprehensive understanding of the underlying physical processes and recurrence intervals. Since instrumental time series rarely exceed a century, geo-archives are adequate tools to examine such events on longer time scales. In particular, lakes with annually laminated (varved) sediments provide continuous high-resolution records of climate and environmental variability. Flood-triggered sediment fluxes of detrital catchment material into these lakes provide long flood time series that can be precisely dated through counting of annual layers. The pre-alpine Lake Ammersee (Southern Germany) is an ideal site for reconstructing long time series of flood frequencies because its annually laminated sediment profile allows precise dating and reliable detection of even microscopic layers by their sedimentological and geochemical characteristics. Furthermore, instrumental time series of local precipitation and runoff can be used for calibrating the palaeo-record. The existing high-resolution Holocene palaeotemperature reconstruction derived from ostracods in Lake Ammersee sediments facilitates the discussion of changes in flood frequency patterns in relation to changes in larger scale climate boundary conditions. A novel methodological approach combining micro-facies analyses, high-resolution element scanning and stable isotope measurements allowed to reconstruct a 450 year time series of detrital layers in two varved sediment cores from Lake Ammersee located 1.8 km apart from each other. The seasonal occurrence of each layer was determined by its micro-stratigraphic position within a varve. The comparison of our record with measured runoff data from the main tributary River Ammer for the last 73 years and the proximal-distal pattern of detrital layer thickness towards the Ammer river mouth confirm the interpretation of these layers as triggered by floods. To better understand the effects of precipitation characteristics on major runoff events we compared our flood layer record with continuous daily precipitation data from the Meteorological Observatory Hohenpei?enberg back to AD 1880. For investigating the role of atmospheric circulation patterns on flood frequencies we compared our record with high-resolution atmospheric pressure field reconstructions of the last 450 years.

Czymzik, M.; Brauer, A.; Plessen, B.; Dulski, P.; von Grafenstein, U.

2009-12-01

102

Mediterranean (Annually?) Laminated Sediments of Miocene to Pleistocene age; a Study of Seasonal Variability During Precession Minima.  

NASA Astrophysics Data System (ADS)

Laminated sediments are increasingly sought as an excellent archive of paleo-environmental change at a very high temporal resolution comparable to that of ice cores, tree rings and corals. They are found in widely different settings ranging from lacustrine and shallow to deep marine depositional environments. Laminated sediments dominantly reflect the annual cycle, but they can also have a daily or interannual origin or record episodic events such as storm floods. In the Mediterranean Neogene the most conspicuous type of sedimentary cycles is the alternation of homogeneous marls and brown to black coloured, often well-laminated beds enriched in organic carbon, termed sapropels. Sapropels are not distributed evenly or randomly in the stratigraphic succession but display characteristic cycle patterns which reflect the influence of the three orbital parameters (precession, obliquity, and eccentricity). Individual sapropels are related to precession minima and sapropel clusters to eccentricity maxima. Besides sapropels, several other types of laminites are found throughout the Mediterranean. We intend to study diatomites and diatomitic sapropels of Messinian to Pleistocene age which are present in several land sections in Southern Italy. Initial research focuses on the description and classification of laminations found in two Late Pliocene sapropels from the Vrica section of southern Italy. They may provide considerable insight into the biological and sedimentation responses to climate forcing at times of maximum seasonal contrast (i.e. precession minima). In this respect, it is of crucial importance to determine whether the laminations are of annual origin. At a later stage research will also focus on diatomites of various ages in order to compare the different types of laminations present. Such laminated sapropels and diatomites may be used as an excellent geochronometer to detect multi-annual to centennial periodicities in the Mediterranean paleoclimate. Image analysis of the Vrica d and e sapropels will further provide a clearer insight into the duration of sapropel formation. Back scattered electron microscopy has been used extensively by several workers for the analyses of fine laminations, e.g. Dean et al. (1999). Images produced using this method may provide valuable information regarding sedimentological and oceanographical processes at the the time of depositioning. A major problem in this study is the impregnation of the sediment due to the very low porosity of the clays (i.e. poor penetration). First results, however, show that impregnation with Synolite resin is fairly successful. Other types of resin are currently being tested for the impregnation of diatomites. Dean, J. M., A. E. S. Kemp, et al. (1999). "Taking varves to bits: Scanning electron microscopy in the study of laminated sediments and varves." Journal of Paleolimnology 22: pp. 121-136.

Huiskamp, F. P.; Hilgen, F. J.; Lourens, L. J.

2001-05-01

103

Comparisons of Radiocarbon Ages of Alkenones With Planktonic Foraminifera and Total Organic Carbon in Oceanic Surface Sediments  

NASA Astrophysics Data System (ADS)

To further evaluate the fidelity of alkenones as molecular stratigraphic markers, we have measured radiocarbon ages of alkenones as well as coexisting planktonic foraminifera and total organic carbon (TOC) in the surface sediments collected from a range of depositional settings (Gulf of Mexico, Arabian Sea, Indian Ocean, NE Pacific margin, NW Atlantic margin, Bermuda Rise, south Atlantic, etc.). Radiocarbon ages of alkenones are equivalent with those of planktonic foraminifera in sediments from the Arabian Sea, and Indian Ocean. However, at the other sites investigated alkenones are significantly older than those of the corresponding planktonic foraminifera. We ascribe these age differences to sedimentary processes influencing coarse-grained foraminifera and alkenones associated with fine-grained particles. The latter are more susceptible to resuspension, advection and redeposition by oceanic currents. Alkenone ages are, on average, younger than TOC ages at the study locations. The age difference appears to be greatest in coastal sediments, which could be explained by the contribution of old terrigenous organic matter.

Ohkouchi, N.; Mollenhauer, G.; Eglinton, T. I.

2003-12-01

104

Statistical modelling and power analysis for detecting trends in total suspended sediment loads  

NASA Astrophysics Data System (ADS)

The export of sediments from coastal catchments can have detrimental impacts on estuaries and near shore reef ecosystems such as the Great Barrier Reef. Catchment management approaches aimed at reducing sediment loads require monitoring to evaluate their effectiveness in reducing loads over time. However, load estimation is not a trivial task due to the complex behaviour of constituents in natural streams, the variability of water flows and often a limited amount of data. Regression is commonly used for load estimation and provides a fundamental tool for trend estimation by standardising the other time specific covariates such as flow. This study investigates whether load estimates and resultant power to detect trends can be enhanced by (i) modelling the error structure so that temporal correlation can be better quantified, (ii) making use of predictive variables, and (iii) by identifying an efficient and feasible sampling strategy that may be used to reduce sampling error. To achieve this, we propose a new regression model that includes an innovative compounding errors model structure and uses two additional predictive variables (average discounted flow and turbidity). By combining this modelling approach with a new, regularly optimised, sampling strategy, which adds uniformity to the event sampling strategy, the predictive power was increased to 90%. Using the enhanced regression model proposed here, it was possible to detect a trend of 20% over 20 years. This result is in stark contrast to previous conclusions presented in the literature.

Wang, You-Gan; Wang, Shen S. J.; Dunlop, Jason

2015-01-01

105

77 FR 62396 - Annual Company-Run Stress Test Requirements for Banking Organizations With Total Consolidated...  

Federal Register 2010, 2011, 2012, 2013, 2014

...7100-AD-86 Annual Company-Run Stress Test Requirements for Banking Organizations...financial regulatory agency to conduct stress tests on an annual basis. The Board is adopting...rule to implement the company-run stress test requirements in the Dodd-Frank Act...

2012-10-12

106

Distribution and transport of total mercury and methylmercury in mercury-contaminated sediments in reservoirs and wetlands of the Sudbury River, east-central Massachusetts  

USGS Publications Warehouse

Total mercury and methylmercury were measured in 4 reservoir cores and 12 wetland cores from Sudbury River. The distribution of total mercury and methylmercury in these cores was evaluated to determine the potential for total mercury and methylmercury transport from reservoir and wetlands sediments to the water column. Concentrations of methylmercury were corrected for an analytical artifact introduced during the separation distillation used in the analysis procedure. Corrected methylmercury concentrations correlated with total mercury concentrations in bulk sediment from below the top layers of reservoir and wetland cores; methylmercury concentrations at the top layers of cores were relatively high, however, and were not correlated with total mercury concentrations. Concentrations of methylmercury in pore water were positively correlated with methylmercury concentrations in the bulk sediment. High concentrations of total mercury and methylmercury in sediment (73 and 0.047 micrograms per gram dry-weight basis, respectively) contributed less to the water column in the reservoir than in the wetlands probably because of burial by low concentration sediment and differences in the processes available to transport mercury from the sediments to the water in the reservoirs, as compared to the wetlands .

Colman, John A.; Waldron, Marcus C.; Breault, Robert F.; Lent, Robert M.

1999-01-01

107

Effects of Small Impoundments on Total Watershed Sediment Yield in Northeast Kansas, April through August 2011  

E-print Network

................................................................................. 37 19. Figure 19: Elevation-storage curves for Dam 38 showing extension below surveyed area and corrections applied to set minimum elevation to zero storage .............................................. 47 20. Figure 20: Flow and suspended..., total inflow was split according to each inlet?s percentage of the total drainage area. In cases where one inlet had long periods of bad turbidity data, the SSC was set to be equal for the two forks. In order to better evaluate data at sites...

Foster, Guy M.

2011-12-31

108

Estimating Total Suspended Sediments in Tropical Open Bay Conditions using MODIS  

E-print Network

and geomorphologic balance. This study describes the development and validation of an algorithm to estimate total analysis the lower error was encountered when using an exponential equation, however linear equations, chemical and geomorphological processes are affected by the distribution and abundance of suspended

Gilbes, Fernando

109

Export of dissolved organic and inorganic nitrogen and total suspended sediments across an urbanization gradient in four tropical rivers of Venezuela  

NASA Astrophysics Data System (ADS)

We determined monthly concentrations of total dissolved nitrogen (TDN), dissolved inorganic nitrogen (DIN), dissolved organic nitrogen (DON) and total suspended sediment (TSS) from 4 Venezuelan watersheds from August 2008 to September 2009. Three of these watersheds are mountainous rivers (Tuy, Neverí and Manzanares) and one is flat (Unare River). The three mountainous rivers vary in the degree of urbanization, with the Tuy hosting Caracas, the largest city in Venezuela. We found an order of magnitude larger TDN concentrations in the Tuy, which is impacted mainly by untreated point sources derived from Caracas metropolitan area. The largest TSS values were observed in the three mountainous rivers (Tuy, Neveri and Manzanares). TDN and TSS concentrations varied seasonally with larger TDN and lower TSS values during the dry season for all rivers. Most of the annual discharge of TDN (92%) and TSS (97%) takes place during the rainy season. Our results suggest that urbanization is the largest contributor affecting the composition and magnitude of TDN, whereas orography and local hydrology control the discharge of both TSS and TDN. We calculated the Water Pollution Level (WPL) for DIN and DON to determine the degree of contamination of these species in the evaluated watersheds. WPL values less than 1 indicate that there is in average enough dilution capacity in the river to assimilate the pollutant, whereas WPL larger than 1 indicate that the pollution assimilation capacity has been surpassed. All our evaluated rivers but the Tuy River show WPL-DIN and WPL-DON values between 0.1 and 0.96. The Tuy River had a WPL-DIN=6.3 and WPL-DON= 7.5. We attribute the Tuy River's large DIN and DON contamination to untreated urban point sources due to the strong correlation between population density and DIN and DON concentration from the evaluated watersheds. Our results suggest that urgent water treatment is required for this watershed to diminish the impact in coastal ecosystems.

Rasse, R. J.; Perez, T.; Giuliante, A.; Donoso, L.

2012-12-01

110

Paleoenvironmental changes during the last 8,500 years recorded in annually laminated sediments from Lake Szurpi?y, NE Poland  

NASA Astrophysics Data System (ADS)

Annually laminated (varved) lake sediments provide a precise time scale for high-resolution paleoenvironmental reconstructions of climatic change and human impact. We reconstructed the environmental changes from Lake Szurpi?y (NE Poland) using varve chronology and multi-proxy interdisciplinary approach. Our reconstruction is one of the few for NE Poland and extends the geographical network of laminated lacustrine sediments. This research was supported by the Polish Ministry of Science and Higher Education grants (N N306 275635, N N306 009337, N N306 291639). It is a contribution to the bilateral scientific program "Northern Polish Lake Research" (NORPOLAR). Parallel overlapping sediment cores with total length of 12.38 m and extending back to the Late Glacial were retrieved in 2007. The geochemical (X-ray Fluorescence, CNS, stable isotopes), microscopic (varve thickness and structure), biological (diatoms, pollen) and statistical analyses were applied and combined in an annual scale based on the varve chronology, which was verified by independent radiometric dating (Pb-210, Cs-137 and AMS radiocarbon dating). Due to the large slump, this study focuses on the almost continuously varved uppermost 7.58-m long section of the profile, covering the last 8,500 years. The climate fluctuations were the main cause of the environmental changes during the first 6,000 years. The geochemical record is mainly driven by the lake productivity, oxic conditions and minerogenic input. Although the first evidence of the anthropogenic impact is documented in pollen record at 8,000 BP, the environmental conditions were relatively stable until 2,500 BP, when the human activity increased significantly. Since that time the climatic and human influence are combined and more difficult to disentangle. Three settlement phases separated by natural regeneration of the environment occurred between 2,500-400 BP. The variation of geochemical and pollen data at 400-100 BP reflects climate fluctuations during Little Ice Age. The synchronous distinct change in the variability of ?13C, lithogenic elements, C/N ratio and pollen (high percentage of Bryales) may be interpreted as the allochtonous organic matter enrichment related to forest clearing and soil erosion. The lake productivity increased possibly due to the peat bogs drainage and agriculture development. The lake become eutrophic in the last period (since 150 BP).

Kinder, Ma?gorzata; Tylmann, Wojciech; Bubak, Iwona; Enters, Dirk; Kupryjanowicz, Miros?awa; Mayr, Christoph; Ohlendorf, Christian; Piotrowska, Natalia; Zolitschka, Bernd

2014-05-01

111

ANNUAL REPORT. THE INFLUENCE OF CALCIUM CARBONATE GRAIN COATINGS ON CONTAMINANT REACTIVITY IN VADOSE ZONE SEDIMENTS  

EPA Science Inventory

The primary objective of this project is to investigate the role of calcium carbonate grain coatings on adsorption and heterogeneous reduction reactions of key chemical and radioactive contaminants in sediments on the Hanford Site. Research will ascertain whether these coatings p...

112

A comparative study of metal pollution and potential eco-risk in the sediment of Chaohu Lake (China) based on total concentration and chemical speciation.  

PubMed

Total and extractable concentrations of Cu, Pb, and Zn were determined in surface sediments of west Chaohu Lake (China) by HCl-HNO3-HF-HClO4 digestion and an optimized BCR sequential extraction procedure, respectively. The metal pollution was evaluated by the enrichment factor approach, and the potential eco-risk was evaluated by the sediment quality guideline (SQG) and risk assessment code (RAC) assessments. The results indicated that both total and extractable metal concentrations were highly variable and were affected by sediment properties, even though the sediments were predominantly composed of <63-?m particles (>89%). Enrichment factors of the metals based on the total and extractable concentrations all showed higher values in the northern lake area and decreasing values towards the south. This distribution indicated an input of anthropogenic metals via the Nanfei River. Anthropogenic Cu, Pb, and Zn in surface sediments showed comparable values for each metal based on the total and extractable concentrations, suggesting that anthropogenic Cu, Pb, and Zn resided predominantly in the extractable fractions. Sediment Cu had low eco-risk, and Pb and Zn had medium eco-risk by the SQG assessment, whereas the eco-risk rankings of Cu, Pb, and Zn were medium, low, and low-high, respectively, by the RAC assessment. Referencing to the labile (dilute acid soluble) metal concentrations, we deduced that the eco-risk of Cu may be largely overestimated by the RAC assessment, and the eco-risk of Pb may be largely overestimated by the SQG assessment. Overall, sediments Cu and Pb may pose low eco-risk, and Zn may pose low-high eco-risk. PMID:24566968

Liu, Enfeng; Shen, Ji

2014-06-01

113

24 CFR 884.104 - Maximum total annual contract commitment and project account (private-owner or PHA-owner projects).  

Code of Federal Regulations, 2014 CFR

...Maximum total annual contract commitment and project account (private-owner or PHA-owner projects). 884.104 Section 884.104 Housing...SET-ASIDE FOR SECTION 515 RURAL RENTAL HOUSING PROJECTS Applicability, Scope and Basic...

2014-04-01

114

24 CFR 884.104 - Maximum total annual contract commitment and project account (private-owner or PHA-owner projects).  

Code of Federal Regulations, 2011 CFR

...Maximum total annual contract commitment and project account (private-owner or PHA-owner projects). 884.104 Section 884.104 Housing...SET-ASIDE FOR SECTION 515 RURAL RENTAL HOUSING PROJECTS Applicability, Scope and Basic...

2011-04-01

115

24 CFR 884.104 - Maximum total annual contract commitment and project account (private-owner or PHA-owner projects).  

Code of Federal Regulations, 2013 CFR

...Maximum total annual contract commitment and project account (private-owner or PHA-owner projects). 884.104 Section 884.104 Housing...SET-ASIDE FOR SECTION 515 RURAL RENTAL HOUSING PROJECTS Applicability, Scope and Basic...

2013-04-01

116

24 CFR 884.104 - Maximum total annual contract commitment and project account (private-owner or PHA-owner projects).  

Code of Federal Regulations, 2012 CFR

...Maximum total annual contract commitment and project account (private-owner or PHA-owner projects). 884.104 Section 884.104 Housing...SET-ASIDE FOR SECTION 515 RURAL RENTAL HOUSING PROJECTS Applicability, Scope and Basic...

2012-04-01

117

Spatial distribution and concentration assessment of total petroleum hydrocarbons in the intertidal zone surface sediment of Todos os Santos Bay, Brazil.  

PubMed

The primary objective of this study was to investigate the concentrations and spatial distribution of the total petroleum hydrocarbons (TPHs) in the intertidal zone surface sediment of Todos os Santos Bay, Brazil, to assess the distribution and degree of contamination by TPHs, measure the level of TPH degradation in the surface sediment, and identify the organic matter sources. The surface sediment used in this study was collected in 50 stations, and TPHs, isoprenoid alkanes (pristane and phytane), and unresolved complex mixture (UCM) were analyzed by gas chromatography with a flame ionization detector. The total concentrations ranged from 0.22 to 40,101 ?g g(-1) dry weight and showed a strong correlation with the total organic carbon (TOC) content. The highest TPH concentrations were observed in samples from the mangrove sediments of a river located near a petroleum refinery. Compared with other studies in the world, the TPH concentrations in the intertidal surface sediment of Todos os Santos Bay were below average in certain stations and above average in others. An analysis of the magnitude of UCM (0.11 to 17,323 ?g g(-1) dry weight) and the ratios nC17/Pr and nC18/Ph suggest that an advanced state of oil weathering, which indicates previous contamination. The molar C/N ratios varied between 5 and 43, which indicate organic matter with a mixed origin comprising marine and continental contributions. PMID:24100798

Silva, Carine S; Moreira, Icaro T A; de Oliveira, Olivia M C; Queiroz, Antonio F S; Garcia, Karina S; Falcão, Brunno A; Escobar, Narayana F C; Rios, Mariana Cruz

2014-02-01

118

Measurement of total polycyclic aromatic hydrocarbon concentrations in sediments and toxic units used for estimating risk to benthic invertebrates at manufactured gas plant sites.  

PubMed

The U.S. Environmental Protection Agency's (U.S. EPA) narcosis model requires the measurement of 18 parent and 16 groups of alkyl polycyclic aromatic hydrocarbons (PAHs) (so-called 34 PAHs) in sediments to calculate the number of PAH toxic units (TU) available to benthic organisms. If data for the 34 PAHs are not available, the U.S. EPA proposes estimating the risk by multiplying the TU for 13 parent PAHs by 11.5 (95% confidence interval) based on data from 488 sediments. This estimate is overly conservative for PAHs from pyrogenic manufactured gas plant (MGP) processes based on the analysis of 45 sediments from six sites. Parent PAHs contributed approximately 40% of the total concentrations and TU for MGP sediments. In contrast, parent PAHs from diesel fuel and petroleum crude oil contributed only 2 and 1%, respectively, of the PAH concentrations and TU, compared to approximately 98 to 99% contributed by the alkyl PAHs. Statistical comparison of the TU based on the measured 34 alkyl and parent PAHs and those based on only 13 parent PAHs demonstrated that a factor of 4.2 (rather than 11.5) is sufficient to estimate total TU within a 95% confidence level for MGP sites. Similarly, measurement of parent PAHs is sufficient to accurately estimate the total 34 alkyl and parent PAH concentrations for MGP-impacted sediments. PMID:16494254

Hawthorne, Steven B; Miller, David J; Kreitinger, Joseph P

2006-01-01

119

Effect of pH, sulphate concentration and total organic carbon on mercury accumulation in sediments in the Volta Lake at Yeji, Ghana.  

PubMed

In this study, pH, total organic carbon, sulphate concentration and mercury concentrations of sediment samples from the Volta Lake at Yeji in the northern part of Ghana were determined. The results indicate that pH ranged from 6.32 to 8.21, total organic carbon ranged from 0.17 to 3.02 g/kg and sulphate concentration from 10.00 to 57.51 mg/kg. Total mercury concentrations ranged from 32.61 to 700 ng/g which is below the International Atomic Energy Agency recommended value of 810 ng/g. Humic substance-bound mercury ranged from 81.15 to 481.31 mg/kg in sediments and its two fractions existed as humic acid-bound mercury > fulvic acid-bound mercury with the ratio of humic substance-bound mercury to fulvic acid-bound mercury as 1.62 on the average. Humic substance-bound mercury and the two fractions fulvic acid-bound mercury and humic substance-bound mercury in sediments were favorably determined and found to correlate significantly positive with total organic carbon (r = 0.538) and total mercury (r = 0.574). However, there were poor correlations between SO(4) (2-) concentrations and humic substance-bound mercury (r = -0.391) as well as the two fractions; fulvic acid (r = -0.406) and humic acid (r = -0.381). By assuming that methyl mercury is mostly formed in sediments, these significant relations suggest that the efficiency of mercury being methylated from a given inorganic form depends on the amount, and most likely biochemical composition of total organic carbon in the lake sediment but not the SO(4) (2-) concentration. PMID:22258497

Kwaansa-Ansah, E E; Voegborlo, R B; Adimado, A A; Ephraim, J H; Nriagu, J O

2012-03-01

120

Assessment of Total Aromatic Hydrocarbons, Aliphatic and Polycyclic Aromatic Hydrocarbons in Surface Sediment and Fish from the Gulf of Tunis (Tunisia)  

Microsoft Academic Search

This investigation represents the extensive study of the spatial distribution and sources of hydrocarbons in the Gulf of Tunis. Sediments and fish were sampled within the open sea of the Gulf of Tunis during August 2004. All samples were extracted with organic solvents, separated by silica\\/alumina column chromatography, and analyzed by spectrofluorometry for the determination of total aromatic hydrocarbons (TAH)

Nadia Mzoughi; Lassaad Chouba; Gaëtane Lespes

2010-01-01

121

Using a Total Quality Management Team To Improve Student Information Publications. AIR 1992 Annual Forum Paper.  

ERIC Educational Resources Information Center

A Total Quality Management team was formed at Oregon State University to improve the quality of student information publications. The team studied the critical process in detail, identified "customers" of student information publications, defined information to be solicited from the customers, interviewed them, and gathered data for improving the…

Frost, Jacquelyn L.; Beach, Gary L.

122

Dioxin Chronology and Fluxes in Sediments of the Houston Ship Channel, Texas: Influences of Non-steady State Sediment Transport and Total Organic Carbon  

NASA Astrophysics Data System (ADS)

Polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins) are persistent contaminants that bio-accumulate and pose serious risks to biota and humans. The primary objective of this study was to determine the history and mechanisms of dioxin accumulation in sediments of the Houston Ship Channel (HSC) using analytical data on natural and anthropogenic radionuclides (7Be, 137Cs and 210Pb) and dioxins. Results showed that present-day sedimentary dioxin accumulation rates are orders of magnitude higher than atmospheric inputs to the HSC, as determined from a wetland sediment core (FW1) and direct measurements. Most stations showed dioxin peaks in the near surface, indicating continuing inputs despite federal regulations. Stations with high dioxin inventories (11270 > 11193 > 16499 > 15979 > 11261) reflect accentuated accumulation in the HSC as one moves west towards Buffalo Bayou (11270, 15979), at the confluence of the HSC and the San Jacinto River (11261) and upstream in the San Jacinto River (11193). While station 11270 had the highest dioxin inventory, and nearby station 11261 had the highest sediment accumulation rates and dioxin fluxes, present-day dioxin fluxes at 11270 are less than average fluxes and inventories for station 11261 are less than average inventories, for all sites. These results support the interpretation that the HSC is influenced by episodic sediment resuspension, erosion and lateral transport processes driven by tides, wind, shipping and dredging, which can cause intermittently high accumulations of dioxins.

Yeager, K.; Santschi, P.; Raifai, H.; Suarez, M.; Brinkmeyer, R.; Hung, C.; Schindler, K.; Andres, M.; Weaver, E.

2007-05-01

123

Relationships among total recoverable and reactive metals and metalloid in St. Lawrence River sediment: bioaccumulation by chironomids and implications for ecological risk assessment.  

PubMed

The availability and bioaccumulation of metals and metalloids, and the geochemical interactions among them, are essential to developing an ecological risk assessment (ERA) framework and determining threshold concentrations for these elements. The purpose of this study was to explore the relationships among total recoverable and reactive metals and metalloid in sediment and their bioaccumulation by chironomids. In the fall of 2004 and 2005, 58 stations located in the three fluvial lakes of the St. Lawrence River and its largest harbour area in Montreal, Canada, were sampled. Nine total recoverable and reactive metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and one metalloid (As) were measured in whole sediment using two extraction methods: HCl/HNO(3) and HCl 1N, respectively. The bioaccumulation of six metals (Cd, Cr, Cu, Ni, Pb and Zn) and As by chironomids was evaluated in a subset of 22 stations. Strong collinearities were observed between some total recoverable or reactive metal concentrations in sediment; two principal clusters, including collinear metals, were obtained. The first one included metals of mainly geological origin (Al, Cr, Fe, Mn, Ni), while the second one included As, Cd, Cu, Pb and Zn, which likely derive mainly from point sources of anthropogenic contamination. Each element also showed strong collinearity between their total recoverable and reactive forms (0.65< or =r < or =0.97). We can conclude that both chemical forms are equivalent for use in statistical models needed to explain biological responses and also in screening risk assessment. However, these relationships are not always proportional. Lower availability percentages were observed for Cd, Cu and Zn in the highly mixed-contaminated area of the Montreal Harbour, even though concentrations in sediment were higher. We observed a significant correlation (0.50< or =r < or =0.56) between concentrations in chironomids and concentrations of both total recoverable and reactive Cr and Pb in sediment. Arsenic was an exception, with accumulation by chironomids being highly related to reactive sediment concentrations. Finally, we observed variable influences of explanatory factors (e.g. sediment grain size, Al, Fe, Mn, S, TOC), depending on which metal or metalloid was being predicted in chironomids. In this context, it is difficult to choose a universal predictive method to explain the bioaccumulation of specific metals, and more research is still needed into normalization procedures that consider a combination of explanatory factors. PMID:17900660

Desrosiers, Mélanie; Gagnon, Christian; Masson, Stéphane; Martel, Louis; Babut, Marc P

2008-01-15

124

Sediment discharge in the Colorado River near De Beque, Colorado  

USGS Publications Warehouse

A study was conducted to determine annual-sediment discharge at the site of a proposed reservoir on the Colorado River at Una, located 3 miles upstream from De Beque, Colorado. Eleven suspended sediment samples were collected during 1984 at the De Beque bridge. These data were combined with suspended sediment data collected for the Colorado River at two nearby streamflow gaging stations to define relations between suspended-sediment discharge and stream discharge. Best results were obtained when the data were separated into two periods, March through October, and November through February. The data for March through October were separated into two periods: (1) Rising stream-stage period, which includes data collected prior to the data of the annual peak-stream discharge, and (2) falling stream-stage period, which includes data collected after the date of the annual peak-stream discharge. Nine bedload samples were collected during 1984 to determine the contribution of bedload sediment discharge to total sediment discharge. Bedload accounted for < 2% of total sediment discharge. The best relations describing bedload sediment discharge were obtained when the bedload data were separated into two periods: (1) Data collected prior to the date of the annual peak-stream discharge, and (2) data collected after the date of the annual peak-stream discharge. Mean annual sediment discharge in the Colorado River at the proposed Una reservoir site was estimated to be 1,065,000 tons/year for October 1966 through September 1984. Water storage capacity of the proposed reservoir would decrease about 30% after 100 years at this sediment discharge rate. (USGS)

Butler, D.L.

1986-01-01

125

Quantitative determination of polyphosphate in sediments using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and partial least squares regression.  

PubMed

Phosphorus (P) is a major cause of eutrophication and subsequent loss of water quality in freshwater ecosystems. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. Despite the broad relevance of polyphosphate (Poly-P) in bioremediation and P release processes in the environment, its quantification is not yet well developed for sediment samples. Current methods possess significant disadvantages because of the difficulties associated with using a single extractant to extract a specific P compound without altering others. A fast and reliable method to estimate the quantitative contribution of microorganisms to sediment P release processes is needed, especially when an excessive P accumulation in the form of polyphosphate (Poly-P) occurs. Development of novel approaches for application of emerging spectroscopic techniques to complex environmental matrices such as sediments significantly contributes to the speciation models of P mobilization, biogeochemical nutrient cycling and development of nutrient models. In this study, for the first time Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy in combination with partial least squares (PLS) was used to quantify Poly-P in sediments. To reduce the high absorption matrix components in sediments such as silica, a physical extraction method was developed to separate sediment biological materials from abiotic particles. The aim was to achieve optimal separation of the biological materials from sediment abiotic particles with minimum chemical change in the sample matrix prior to ATR-FTIR analysis. Using a calibration set of 60 samples for the PLS prediction models in the Poly-P concentration range of 0-1 mg g(-1) d.w. (dry weight of sediment) (R(2) = 0.984 and root mean square error of prediction RMSEP = 0.041 at Factor-1) Poly-P could be detected at less than 50 ?g g(-l) d.w. Using this technique, there is no solvent extraction or chemical treatment required, sample preparation is minimal and simple, and the analysis time is greatly reduced. The results from this study demonstrated the potential of ATR FT-IR spectroscopy as an alternative method to study Poly-P in sediments. PMID:22801463

Khoshmanesh, Aazam; Cook, Perran L M; Wood, Bayden R

2012-08-21

126

Recruitment of Total Phytoplankton, Chlorophytes and Cyanobacteria from Lake Sediments Recorded by Photosynthetic Pigments in a Large, Shallow Lake (Lake Taihu, China)  

NASA Astrophysics Data System (ADS)

Recruitment of total phytoplankton, chlorophytes and cyanobacteria from lake sediments to the water column was studied using photosynthetic pigments at one site (1.5 m) in Lake Taihu, a large shallow lake in China. Samples were taken weekly from the migration traps installed on the bottom from March to May 2004. Abundance of total phytoplankton, chlorophytes and cyanobacteria were represented by Chlorophyll (Chl) a, b, and phycocyanin (PC), respectively. Over the three months, total phytoplankton, chlorophytes, and cyanobacteria corresponding to 48.9%, 68.9% and 316.2% of their initial concentrations in surface sediments were recruited in Lake Taihu. However, compared with their increase in pelagic abundance over the same period, the recruitment accounted for a rather small inoculum. Accompanying the recruitment, total phytoplankton and chlorophytes declined and cyanobacteria increased in the upper 0-2 cm sediments; colonies of Microcystis aeruginosa in the water column enlarged from small size with several cells to large colonies with hundreds of cells. Thus, overwintering and subsequent growth renewal of pelagic phytoplankton merits further study and comparison with benthic survival and recruitment.

Cao, Huan-Sheng; Kong, Fan-Xiang; Tan, Jian-Kang; Zhang, Xiao-Feng; Tao, Yi; Yang, Zhou

2005-08-01

127

Analysis of bottom sediment to estimate nonpoint-source phosphorus loads for 1981-96 in Hillsdale Lake, northeast Kansas  

USGS Publications Warehouse

Bottom sediment in Hillsdale Lake, northeast Kansas, was analyzed as a means of estimating the annual load of total phosphorus deposited in the lake from nonpoint sources. Topographic, bathymetric, and sediment-core data were used to estimate the total mass of phosphorus in the lake-bottom sediment. Available streamflow and water-quality data were used to compute the mean annual mass of phosphorus (dissolved plus suspended) exiting the lake as well as the mean annual load of phosphorus added to the lake from point sources. A simple mass balance then was used to compute the mean annual load of phosphorus from nonpoint sources. Mean annual sediment deposition from 1981 through 1996 was estimated to be 265 million pounds (120 million kilograms). The total mass of phosphorus in the lake-bottom sediment was estimated to be 924,000 kilograms, with a mean annual load of 62,000 kilograms. The mean annual mass of phosphorus exiting in the lake out-flow was estimated to be about 8,000 kilograms. The mean annual loads of phosphorus added to the lake from point and nonpoint sources were estimated to be 5,000 and 65,000 kilograms, respectively. Thus, the contribution to the total mean annual phosphorus load in Hillsdale Lake from point sources is about 7 percent and from nonpoint sources, about 93 percent.

Juracek, K.E.

1997-01-01

128

Fluorine in the rocks and sediments of volcanic areas in central Italy: total content, enrichment and leaching processes and a hypothesis on the vulnerability of the related aquifers.  

PubMed

Rock, sediment and water samples from areas characterised by hydrothermal alterations in the Sabatini and Vico Volcanic Districts, near Rome and the large city of Viterbo, respectively, were collected and analysed to determine the total fluorine (F) content and to understand the F geochemical background level in the volcanic districts of central Italy. Leaching and alteration processes controlling the high concentration of F in water were also investigated. Fluorine concentrations were directly determined (potentiometrically) by an F selective electrode in water samples, while the procedure for rock samples included preliminary F dissolution through alkaline fusion. F concentrations higher than 800 mg kg(-1) were commonly found in the analysed rocks and sediments; the concentration depended on the lithology and on the distance from the alteration areas. A specific successive sampling campaign was conducted in three areas where the F content in sediments was particularly high; in the same areas, measurements of CO(2) flux were also performed to investigate the possible deep origin of F. To verify the relationships among the high F contents in rocks and sediments, the leaching processes involved and the presence of F in the aquifer, we also collected water samples in the western sector of the Sabatini Volcanic District, where hydrothermal manifestations and mineral springs are common. The data were processed using a GIS system in which the F distribution was combined with morphological and geological observations. The main results of our study are that (1) F concentrations are higher in volcanic and recently formed travertine (especially in hydrothermally altered sediments) than in sedimentary rocks and decrease with distance from hydrothermal alteration areas, (2) F is more easily leached from hydrothermally altered rocks and from travertine and (3) sediments enriched with F may indicate the presence of deep regional fractures that represent direct pathways of hydrothermal fluids from the crust to the surface. PMID:21968879

De Rita, Donatella; Cremisini, Carlo; Cinnirella, Alessandro; Spaziani, Fabio

2012-09-01

129

Total petroleum hydrocarbons and heavy metals in the surface sediments of Bohai Bay, China: long-term variations in pollution status and adverse biological risk.  

PubMed

Surface sediments collected from 2001 to 2011 were analyzed for total petroleum hydrocarbons (TPH) and five heavy metals. The sediment concentration ranges of TPH, Zn, Cu, Pb, Cd and Hg were 6.3-535 ?g/g, 58-332 ?g/g, 7.2-63 ?g/g, 4.3-138 ?g/g, 0-0.98?g/g, and 0.10-0.68 ?g/g, respectively. These results met the highest marine sediment quality standards in China, indicating that the sediment was fairly clean. However, based on the effects range-median (ERM) quotient method, the calculated values for all of the sampling sites were higher than 0.10, suggesting that there was a potential adverse biological risk in Bohai Bay. According to the calculated results, the biological risk decreased from 2001 to 2007 and increased afterwards. High-risk sites were mainly distributed along the coast. This study suggests that anthropogenic influences might be responsible for the potential risk of adverse biological effects from TPH and heavy metals in Bohai Bay. PMID:24837025

Zhou, Ran; Qin, Xuebo; Peng, Shitao; Deng, Shihuai

2014-06-15

130

Bioprospecting from Marine Sediments of New Brunswick, Canada: Exploring the Relationship between Total Bacterial Diversity and Actinobacteria Diversity  

PubMed Central

Actinomycetes are an important resource for the discovery of natural products with therapeutic properties. Bioprospecting for actinomycetes typically proceeds without a priori knowledge of the bacterial diversity present in sampled habitats. In this study, we endeavored to determine if overall bacterial diversity in marine sediments, as determined by 16S rDNA amplicon pyrosequencing, could be correlated with culturable actinomycete diversity, and thus serve as a powerful tool in guiding future bioprospecting efforts. Overall bacterial diversity was investigated in eight marine sediments from four sites in New Brunswick, Canada, resulting in over 44,000 high quality sequences (x = 5610 per sample). Analysis revealed all sites exhibited significant diversity (H’ = 5.4 to 6.7). Furthermore, statistical analysis of species level bacterial communities (D = 0.03) indicated community composition varied according to site and was strongly influenced by sediment physiochemical composition. In contrast, cultured actinomycetes (n = 466, 98.3% Streptomyces) were ubiquitously distributed among all sites and distribution was not influenced by sediment composition, suggesting that the biogeography of culturable actinomycetes does not correlate with overall bacterial diversity in the samples examined. These actinomycetes provide a resource for future secondary metabolite discovery, as exemplified by the antimicrobial activity observed from preliminary investigation. PMID:24531187

Duncan, Katherine; Haltli, Bradley; Gill, Krista A.; Kerr, Russell G.

2014-01-01

131

Effects of soil and precipitation dataset resolution on SWAT2005 sediment and total phosphorus simulation accuracy and outputs  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Fort Cobb Reservoir, which is within the Fort Cobb Reservoir Experimental watershed (FCREW) in Oklahoma, is on the Oklahoma 303(d) list (list of water bodies that do not meet the water quality standards as given in the Clean Water Act) based on sedimentation and trophic level of the lake associa...

132

The role of midlatitude mixing barriers in creating the annual variation of total ozone in high northern latitudes  

NASA Astrophysics Data System (ADS)

Data from the HIgh Resolution Dynamics Limb Sounder (HIRDLS), the Microwave Limb Sounder (MLS), and the Whole Atmosphere Community Climate Model (WACCM) are used to investigate the annual variation of total column ozone in high northern latitudes. Downward transport of ozone-rich air by the residual mean circulation during autumn and winter bends ozone isopleths down and increases the high-latitude ozone amounts, leading to an ozone maximum at the end of the winter. During the summer months eddy mixing acts to restore pre-fall distributions of ozone. In this study the large-scale mixing in the lower stratosphere is analyzed using Nakamura's (1996) equivalent length formulation with observed and simulated ozone. The analysis of ozone mixing is performed in the tracer equivalent latitude-potential temperature coordinate system. Steep latitudinal gradients of ozone isopleths below about 500 K occur during the winter, where there are minima in the equivalent length, indicating barriers to mixing at 30°N-40°N. This transport barrier allows large ozone maxima to develop poleward of it. The barrier disappears over the summer, permitting latitudinal mixing of the high ozone air. Above 500 K mixing is more effective during the winter, so a large winter maximum does not occur. In both midlatitude and high latitude the lower stratospheric layer from 330 to 500 K doubles its ozone content from autumn to spring, compared with much smaller changes in the layer from 500 to 650 K. Our results confirm that the presence of the winter transport barrier in the lower stratosphere controls the seasonal variation of total ozone.

Gille, John; Karol, Svetlana; Kinnison, Douglas; Lamarque, Jean-Francois; Yudin, Valery

2014-08-01

133

Wind erosion from a sagebrush steppe burned by wildfire: Measurements of PM10 and total horizontal sediment flux  

NASA Astrophysics Data System (ADS)

Wind erosion and aeolian transport processes are under studied compared to rainfall-induced erosion and sediment transport on burned landscapes. Post-fire wind erosion studies have predominantly focused on near-surface sediment transport and associated impacts such as on-site soil loss and site fertility. Downwind impacts, including air quality degradation and deposition of dust or contaminants, are also likely post-fire effects; however, quantitative field measurements of post-fire dust emissions are needed for assessment of these downwind risks. A wind erosion monitoring system was installed immediately following a desert sagebrush and grass wildfire in southeastern Idaho, USA to measure wind erosion from the burned landscape. This paper presents measurements of horizontal sediment flux and PM10 vertical flux from the burned area. We determined threshold wind speeds and corresponding threshold friction velocities to be 6.0 and 0.20 m s-1, respectively, for the 4 months immediately following the fire and 10 and 0.55 m s-1 for the following spring months. Several major wind erosion events were measured in the months following the July 2010 Jefferson Fire. The largest wind erosion event occurred in early September 2010 and produced 1495 kg m-1 of horizontal sediment transport within the first 2 m above the soil surface, had a maximum PM10 vertical flux of 100 mg m-2 s-1, and generated a large dust plume that was visible in satellite imagery. The peak PM10 concentration measured on-site at a height of 2 m in the downwind portion of the burned area was 690 mg m-3. Our results indicate that wildfire can convert a relatively stable landscape into one that is a major dust source.

Wagenbrenner, Natalie S.; Germino, Matthew J.; Lamb, Brian K.; Robichaud, Peter R.; Foltz, Randy B.

2013-09-01

134

Nutrient, suspended-sediment, and total suspended-solids data for surface water in the Great Salt Lake basins study unit, Utah, Idaho, and Wyoming, 1980-95  

USGS Publications Warehouse

Selected nitrogen and phosphorus (nutrient), suspended-sediment and total suspended-solids surface-water data were compiled from January 1980 through December 1995 within the Great Salt Lake Basins National Water-Quality Assessment study unit, which extends from southeastern Idaho to west-central Utah and from Great Salt Lake to the Wasatch and western Uinta Mountains. The data were retrieved from the U.S. Geological Survey National Water Information System and the State of Utah, Department of Environmental Quality, Division of Water Quality database. The Division of Water Quality database includes data that are submitted to the U.S. Environmental Protection Agency STOrage and RETrieval system. Water-quality data included in this report were selected for surface-water sites (rivers, streams, and canals) that had three or more nutrient, suspended-sediment, or total suspended-solids analyses. Also, 33 percent or more of the measurements at a site had to include discharge, and, for non-U.S. Geological Survey sites, there had to be 2 or more years of data. Ancillary data for parameters such as water temperature, pH, specific conductance, streamflow (discharge), dissolved oxygen, biochemical oxygen demand, alkalinity, and turbidity also were compiled, as available. The compiled nutrient database contains 13,511 samples from 191 selected sites. The compiled suspended-sediment and total suspended-solids database contains 11,642 samples from 142 selected sites. For the nutrient database, the median (50th percentile) sample period for individual sites is 6 years, and the 75th percentile is 14 years. The median number of samples per site is 52 and the 75th percentile is 110 samples. For the suspended-sediment and total suspended-solids database, the median sample period for individual sites is 9 years, and the 75th percentile is 14 years. The median number of samples per site is 76 and the 75th percentile is 120 samples. The compiled historical data are being used in the basinwide sampling strategy to characterize the broad-scale geographic and seasonal water-quality conditions in relation to major contaminant sources and background conditions. Data for this report are stored on a compact disc.

Hadley, Heidi K.

2000-01-01

135

Solar influences on flood frequency in a 450-year time series of detrital layers in annually laminated sediments from pre-alpine Lake Ammersee (Southern Germany)  

NASA Astrophysics Data System (ADS)

Forecasting of extreme events and their impacts on the human habitat requires profound understanding of the triggering mechanisms and recurrence intervals. Since instrumental time series rarely exceed a century, geo-archives are adequate tools to examine such events on longer time scales and under different climate boundary conditions. Annually laminated (varved) lake sediments are continuous high-resolution archives of climate and environmental variability. Flood-triggered sediment fluxes of detrital catchment material into these lakes allow establishing an event stratigraphy with seasonal resolution. Precise time control of these events can be obtained by varve counting. Lake Ammersee in the alpine foreland is an ideal site for the reconstruction of long time series of flood frequencies. The annually laminated sediments enable precise dating and reliable detection of even microscopic flood layers by their sedimentological and geochemical characteristics. The seasonality of each layer can be determined by the micro-stratigraphic position within a varve. Instrumental and historical flood data of the main tributary River Ammer can be used for calibrating the palaeoflood-record. The existing high-resolution Holocene palaeotemperature reconstruction derived from ostracods in Lake Ammersee sediments (von Grafenstein et al., 1999) facilitates the discussion of changes in flood frequency patterns in relation to changes in climate boundary conditions. A combination of micro-facies analyses and high-resolution element scanning (µ-XRF) allowed reconstructing a seasonal 450-year time series of flood layers in two varved sediment cores from Lake Ammersee. A comparison between instrumental River Ammer runoff and weather regimes (Großwetterlagen) data distinguished five main flood-prone weather regimes triggering 71% of extreme Ammer flood events. The agreement of the flood layer record with flood-prone weather regimes and the correlation of flood layer frequency with solar activity suggest changes in mid-latitude atmospheric dynamics related to solar variability. Reference: von Grafenstein U., H. Erlenkeuser, A. Brauer, J. Jouzel, and S.J. Johnson (1999), A Mid-European Decadal Isotope-Climate Record from 15,000 to 5000 Years B.P., Science, 284(5420), 1654-1657, doi:10.1126/science.284.5420.1654.

Czymzik, Markus; Dulski, Peter; Plessen, Birgit; von Grafenstein, Ulrich; Brauer, Achim

2010-05-01

136

Seasonal and inter-annual variations of nitrogen diagenesis in the sediments of a recently impounded basin  

Microsoft Academic Search

The Méry-sur-Oise (France) storage reservoir is an artificial basin of 9 m average depth, fed by water from the river Oise with a mean residence time of about 4 days. Sediments are accumulating at a rate of about 0.7 cm\\/month. In the sediments, two fractions of organic nitrogen with different rates of bacterial degradation could be distinguished, one associated with

Gilles Billen; Sophie Dessery; Christiane Lancelot; Michel Meybeck

1989-01-01

137

Estimating the Contributions of Surface Wash-off and Channel Erosion to Total Sediment and Solute Loads in a Small Mixed Land Use Watershed  

NASA Astrophysics Data System (ADS)

Watershed sediment and solute loads originate from many different sources. These can include point sources, soil erosion, impervious surface wash-off, channel bank and bed erosion, and other sources depending on the land use activities within the watershed. However, the difficulties encountered in quantifying the contributions of specific nonpoint sources to watershed loads magnifies the uncertainty in watershed management efforts aimed at mitigating the pollutants. The goal of this research is to quantify the contribution of wash-off from residentially developed land and stream channel erosion to total watershed sediment and solute loadings within a 103 ha tributary watershed of Potash Brook, in Chittenden County, Vermont. To do so we deployed autosamplers at two stream cross sections and within two representative storm drain outfalls to sample TSS, TN, NO3-, TKN, TP, and Cl-. Samples were collected during storm events on a flow weighted composite basis, and by periodic base flow sampling. In stream sampling was conducted over a total 5 years and storm drain sampling covered a total of 2 years. Preliminary analysis of these data suggests that surface wash-off from developed portions of the watershed can generate greater than 90% of the TSS and greater than 50% of the Cl- loads measured at the watershed outlet sampling location. Currently, these data are being incorporated into an EPA-SWMM model of the watershed coupled with an evolutionary strategies parameter search algorithm. The model generated and measured wash-off data will be used with the measured load data at the watershed outlet to estimate the contribution of the stream channel by difference over all sampled events.

Nipper, J.; Bowden, W. B.

2009-12-01

138

Fluvial-sediment discharge to the oceans from the conterminous United States  

USGS Publications Warehouse

This report is a contribution to the UNESCO-sponsored project of the International Hydrological Decade called the World Water Balance. Annual fluvial-sediment discharge from the conterminous United States averages 491,449,600 short tons, of which 14,204,000 is discharged to the Atlantic Ocean, 378,179,000 to the Gulf of Mexico, and 99,066,600 to the Pacific Ocean. Data from 27 drainage areas were used to estimate the average annual discharge, yield, and concentration of fluvial sediment. The data may be used to extrapolate part of the total world sediment yield to the marine environment.

Curtis, Westley Farnsworth; Culbertson, James J.; Chase, Edith B.

1973-01-01

139

Annual layers in river-bed sediment of a stagnant river-mouth area of the Kitagawa Brook, Central Japan  

NASA Astrophysics Data System (ADS)

The river mouth of Kitagawa Brook is normally stagnant because it is easily closed by sand and gravel transported by littoral currents of Biwa Lake, Japan. A new urban area exists in the basin and sewerage works were constructed in the early 1990s, so contaminated water with a bad odour had flowed into the brook before the sewerage works. To reduce the smell, the river mouth was excavated to narrow the channel in the early 1980s. Thus, river-bed sediment after this excavation only occurs at the river mouth. From the upper 24 cm of a sediment core, we found 19 strata of leaves which were supplied from deciduous trees in autumn. We also found several gravel layers which were supplied from the lake during severe storms. The combination of veins and gravel layers were reconstructed for about 20 years of sediment records with an error of two to three years.

Kurashige, Y.; Nakano, T.; Kasubuchi, E.; Maruo, M.; Domitsu, H.

2015-03-01

140

MOVEMENT OF TRACTIVE SEDIMENT FROM DISTURBED LANDS.  

USGS Publications Warehouse

The Smoky Creek basin of the coal area of northeastern Tennessee shows extensive evidence of tractive movement of coarse sediment from mined tributary basins into the main channel. Coal-rich gravel bars and flood-plain debris are common below tributaries. Using a combination of techniques including channel-geometry and bar measurements, sediment sampling for rock-debris and coal size distributions, and botanical dating of flood events and geomorphic features, an average annual yield of 65 metric tons per square kilometer (187 tons per square mile) for tractively moved sediment has been calculated for the period 1977 to 1982. This value, 8 percent of the total sediment load, is probably an underestimate owing to the method of calculation. Slightly more than half of the traction load is coal, which moves through the basin within a few years. Rock debris, however, appears to require years to decades to move similar distances.

Osterkamp, W.R.; Carey, W.P.; Hupp, C.R.; Bryan, B.A.

1984-01-01

141

Late Quaternary climates of East Asia deduced from the total organic carbon contents of cored sediments (MD179-3304, 3312) off Joetsu City, Japan Sea  

NASA Astrophysics Data System (ADS)

Total organic carbon (TOC) and total nitrogen (TN) concentrations are analyzed with high temporal resolution (ca. 100 years) for cores MD179-3304 and MD179-3312 taken from the Japan Sea off Joetsu City. The temporal changes in TOC and TN concentrations vary quasi-regularly in similar patterns. The age models are formed on the basis of the dates of 14C dating, marker tephra beds, TL layers, and marine isotope events with depth. TOC concentration is high in MIS 1 and 5, low in MIS 2 and 4, and slightly elevated in MIS 3 with frequent short fluctuations. This general trend is very similar to LR04 curve, except for the reduced dominance of TOC around the MIS 5.5 substage. As shown typically in MIS 3, there are many peaks of TOC in a short interval. The details of these TOC peaks can be correlated with the warm interstadials of the Greenland ice core. We can identify a sawtooth-like decreasing trend of TOC in MIS 3. In contrast, the decreasing trend of ?18O in the ice core corresponds to an increasing trend of TOC in MIS 5. The most plausible explanation for the correlation of climate changes between East Asia and the North Atlantic is oscillation of the Arctic polar front through time. The detailed correspondence of TOC concentrations of the Japan Sea sediments to other common paleoclimate proxies means that the TOC concentrations of these sediments is an excellent paleoclimate record in Far East Asia, although the genetic relationship between air temperature and biological productivity in the Japan Sea is as yet unknown.

Urabe, Tasuku; Kuriyama, Manato; Matsumoto, Ryo; Kumon, Fujio

2014-08-01

142

Quasi-biennial oscillation and quasi-biennial oscillation-annual beat in the tropical total column ozone: A two-dimensional model simulation  

NASA Astrophysics Data System (ADS)

The National Centers for Environmental Prediction-Department of Energy Reanalysis 2 data are used to calculate the monthly mean meridional circulation and eddy diffusivity from 1979 to 2002 for use in the California Institute of Technology-Jet Propulsion Laboratory two-dimensional (2-D) chemistry and transport model (CTM). This allows for an investigation of the impact of dynamics on the interannual variability of the tropical total column ozone for all years for which the Total Ozone Mapping Spectrometer and the Solar Backscatter Ultraviolet merged total ozone data are available. The first two empirical orthogonal functions (EOFs) of the deseasonalized and detrended stratospheric stream function capture 88% of the total variance on interannual timescales. The first EOF, accounting for over 70% of the interannual variance, is related to the quasi-biennial oscillation (QBO) and its interaction with annual cycles, the QBO-annual beat (QBO-AB). The 2-D CTM provides realistic simulations of the seasonal and interannual variability of ozone in the tropics. The equatorial ozone anomaly from the model is close to that derived from the observations. The phase and amplitude of the QBO are well captured by the model. The magnitude of the QBO signal is somewhat larger in the model than it is in the data. The QBO-AB found in the simulated ozone agrees well with that in the observed data.

Jiang, Xun; Camp, Charles D.; Shia, Runlie; Noone, David; Walker, Christopher; Yung, Yuk L.

2004-08-01

143

Annual and seasonal temperature variance along an inter-tidal sediment transect in Yaquina bay, Oregon, 1999 - 2006  

EPA Science Inventory

Sediment temperature was measured using submersible Onset TidbiT® recording thermistor thermometers at eelgrass (Zostera marina, Z. japonica) mid-rhizome root depth (~5 cm) at 6 stations on a transect from ~MLLW (mean lower low water) at the channel edge to near MHHW (mean higher...

144

Diatoms (Class Bacillariophyceae) and geochemistry from annually laminated mid-Holocene sediments, west coast Canada: insights into abrupt climate change in the past  

NASA Astrophysics Data System (ADS)

A 115-year record of annually laminated sediments from Effingham Inlet, a small anoxic fjord on the west coast of Vancouver Island, British Columbia (49?N, 125?W), was analyzed for diatoms (species and abundances) and geochemistry (C and N isotopes, organic C and trace elements Ag, Cd, Re and Mo) from a piston core. The sediments were radiocarbon dated at approx. 4200-4400 years before present (yr BP) and show diatom enriched varves in the lower 70 years, with a sudden transition to diatom impoverished varves above. In the lower section, varves are thick (2-5 mm) and consist of well-defined Thalassiosira-Skeletonema-Chaetoceros spring bloom successions. Diatom concentrations average at 787 ± 733 million valves/g of dry sediment, del 15N at 7.0 ± 0.5 per mil, and organic C at 5.2 ± 0.5 wt. %. In the upper section, the varves are thinner (1-2 mm), do not clearly show the seasonal diatom succession, and contain increased terrigenous detritus. Diatom concentrations average at 388 ± 202 million valves/g with an increased relative abundance of benthic and freshwater taxa, del 15N at 7.3 ± 0.6 per mil and organic C at 5.7 ± 0.5 wt. %. Values of del 13C for both sections are similar, averaging at -24.0 ± 0.5 per mil. The trace element concentrations are quite variable throughout the section. However, several thin (<1 cm) nonlaminated intervals show decreased diatom abundances with concomitant increases in trace element concentrations, suggesting short-lived changes in surface productivity, upwelling and nutrient delivery, and/or anoxic conditions. The abrupt transition from diatom-rich to diatom-poor varves could reflect a shift in dominance of the North Pacific High and Aleutian Low atmospheric pressure systems over the northeast Pacific Ocean, not unlike the well-documented 1976/1977 climate regime shift which showed a change in upwelling and nutrient delivery. A transition between warm and sunny climates to cooler and wetter regimes at around 4000 yr BP has been noted in previous paleoenvironmental studies from British Columbia and the northern hemisphere in general. The Effingham Inlet sediment record data will also be compared with modern sediment trap data from the inlet.

Chang, A.; Pedersen, T. F.

2009-04-01

145

ANNUAL PROGRESS REPORT. SPECTROSCOPIC AND MICROSCOPIC CHARACTERIZATION OF CONTAMINANT UPTAKE AND RETENTION BY CARBONATES IN SOILS AND VADOSE ZONE SEDIMENTS  

EPA Science Inventory

This report summarizes work completed after 21 months of a 36-month project. In a previous annual report we described results of contaminant uptake by natural caliche from the Pasco Basin area. The new results described here relate to studies of metal coprecipitation with calcite...

146

Predicting reservoir sedimentation  

E-print Network

(square miles) Average Inflow (cfs) Storage Capacity (acre-feet) Flood control pool Conservation pool Sediment Reserve Total Water surface area (acres) Conservation pool Flood control reservoir Date of impoundment Date of sediment survey Somerville...

Wooten, Stephanie

1997-01-01

147

Challenges in Measuring and Predicting Medium Term (Weeks to Annual) Aeolian Sediment Transport in Beach-Dune Systems  

NASA Astrophysics Data System (ADS)

Coastal dune budgets depend on sediment input by wind from the beach. Calculation of aeolian transport is thus a primary factor to understand coastal dune evolution and beach-dune coupled dynamics. However, measuring aeolian sediment transport in coastal areas presents fundamental technical and conceptual limitations that make numerical modeling difficult. Wind tunnel experiments isolate and reduce the number of variables to study, which is a necessary procedure to clearly manifest mechanistic relationships between cause and effect. But even with refinement and inclusion of new variables, traditional sediment transport formulas derived from wind tunnel experiments do not usually work well in natural areas. Short-term experiments may include precise instrumentation to obtain high frequency, detail time series of variables involved in aeolian transport, but inferring information at larger scales is problematic without knowledge of the timing and magnitude of particular transport events. There are two primary problems in attempting to predict sediment inputs to coastal dunes over periods of weeks, months or years: 1) to determine an appropriate set of predictive equations that incorporate complexities such as surface moisture content, beach width and the presence of vegetation; and 2) to provide quantitative data on these variables for input into the model at this time scale. Remote sensing techniques and the use of GIS software open the possibility to monitor key parameters regulating sediment transport dynamics at high spatial and temporal resolution over time scales beyond short-term experiments. These were applied at Greenwich Dunes, Prince Edward Island National Park (Canada), in an attempt to measure factors affecting aeolian sediment input to the foredune at a medium scale. Three digital cameras covering different sections of the beach and foredune provide time series on shoreline position, fetch distances, vegetation cover, ice/snow presence, or superficial moisture content. The rectification of oblique images to UTM maps allows to keep the spatial variability of these factors, and thus to perform detailed analysis on their complex evolution. Auxiliary instrumentation such as anemometers, safires, or erosion-deposition pins completes the basic set up. Data is processed using ArcGIS 9.2 and PCI Geomatica 9.1, and managed by an ArcCatalog Geodatabase. The coupling of new technologies (digital imagery) with traditional instrumentation (e.g. anemometers), and the extensive GIS capabilities both in the spatial and temporal domain, permits a new set of questions in aeolian coastal research. The overall goal is to obtain information on what is the frequency and magnitude of transport events at the beach or what are the key parameters regulating them. Challenges remain in improving methodologies to measure sediment transport rates. Ironically enough, we are able to obtain high quality time series on the factors affecting aeolian transport at the beach, but actual transport rates are measured with rather rudimentary techniques or instrumentation not adapted to meso-scale monitoring. This information is needed to test new approaches in modeling and understanding aeolian sediment input from the beach to the foredunes.

Delgado-Fernandez, I.

2009-05-01

148

Understanding Stream Channel Sediment Source Contributions For The Paradise Creek Watershed In Northern Idaho  

NASA Astrophysics Data System (ADS)

Excess sediment from agricultural areas has been a major source of impairment for water bodies, resulting in the implementation of mitigation measures across landscapes. Watershed scale reductions often target upland erosion as key non-point sources for sediment loading. Stream channel dynamics, however, also play a contributing role in sediment loading in the form of legacy sediments, channel erosion and deposition, and buffering during storm events. In-stream contributions are not well understood, and are a potentially important consideration for Total Maximum Daily Loads (TMDLs). The objective of this study is to differentiate stream bank and stream bed sediment contributions and better understand the role of legacy sediments. The study area is the Paradise Creek Watershed in northern Idaho. We modeled sediment yield to the channel system using the Water Erosion Prediction Project (WEPP) model, and subsequent channel erosion and deposition using CONCEPTs. Field observations of cross-sections along the channel system over a 5-year period were collected to verify model simulations and to test the hypothesis that the watershed load was composed predominantly of legacy sediments. Our modeling study shows that stream channels contributed to 39% of the total annual sediment load for the basin, with a 19-year time lag between sediments entering the stream to leaving the watershed outlet. Observations from long-term cross sectional data in the watershed, and a sediment fingerprinting analysis will be presented to better understand sediment contributions from within the stream channel system.

Rittenburg, R.; Boll, J.; Brooks, E. S.

2013-12-01

149

Erosion, sediment discharge, and channel morphology in the Upper Chattahoochee River basin, Georgia  

USGS Publications Warehouse

Average annual rates of sheet erosion and sediment discharge were computed for several watersheds in the Upper Chattahoochee River basin in Georgia. Erosion yields ranged from about 900 to 6,000 tons per year per square mile in nine watersheds and were greatest where land use is largely agricultural or transitional. Suspended sediment yields from the same watershed ranged from about 300 to 800 tons per year per square mile and were greatest from urban areas and least from mostly forested watersheds. The impact of suspended sediment on stream quality was evaluated for 14 watersheds. In general, 60 percent or more of the total annual discharge of trace metals and phosphorus was contributed by suspended sediment. Yields of trace metals and nutrients in suspension were consistently greater in urban watersheds. Turbidity in basin streams increased geometrically with increasing concentrations of suspended sediment. (Woodard-USGS)

Faye, Robert E.; Carey, W.R.; Stamer, J.K.; Kleckner, R.L.

1978-01-01

150

Effects of Alder Mine on the Water, Sediments, and Benthic Macroinvertebrates of Alder Creek, 1998 Annual Report.  

SciTech Connect

The Alder Mine, an abandoned gold, silver, copper, and zinc mine in Okanogan County, Washington, produces heavy metal-laden effluent that affects the quality of water in a tributary of the Methow River. The annual mass loading of heavy metals from two audits at the Alder Mine was estimated to exceed 11,000 kg per year. In this study, water samples from stations along Alder Creek were assayed for heavy metals by ICP-AES and were found to exceed Washington State's acute freshwater criteria for cadmium (Cd), copper (Cu), selenium (Se), and zinc (Zn).

Peplow, Dan

1999-05-28

151

Modelling the contribution of individual radionuclides to the total gamma air kerma rate for the sediments of the Ribble Estuary, NW England.  

PubMed

The aim of this study was to test the performance of a published dose-rate model, investigate the contribution of individual radionuclides to the total gamma air kerma rate (GAKR) and derive external doses to man in the Ribble Estuary, NW England. GAKRs were measured and sediment cores were collected in order to determine radionuclide specific activities with depth. The latter values were used as input data for the external dose-rate model. The model has a slight tendency to over-predict the GAKR, but, on average, the model predictions fall within +/-26% of the measured value. Improvements, in the present case, might be made by accounting for core shortening and variations in soil density in the input data. The model predicted that, for exposed intertidal mud sites, a range of GAKRs between 0.011 and 0.022 microGy h(-1) was attributable to Springfields discharges alone. The contribution due to 234mPa and 234Th ranged between 20 and 60%. An excess GAKR (GAKR arising from anthropogenic emissions alone) of 0.139-0.150 microGy h(-1), used in conjunction with relevant habit-survey data (for a potential critical group) and conversion factors, yielded a dose to man of 0.029-0.031 mSv year(-1). PMID:10616780

Brown, J E; McDonald, P; Williams, M; Parker, A; Rae, J E

1999-12-01

152

Total Quality Management: Statistics and Graphics III - Experimental Design and Taguchi Methods. AIR 1993 Annual Forum Paper.  

ERIC Educational Resources Information Center

Interest in Total Quality Management (TQM) at institutions of higher education has been stressed in recent years as an important area of activity for institutional researchers. Two previous AIR Forum papers have presented some of the statistical and graphical methods used for TQM. This paper, the third in the series, first discusses some of the…

Schwabe, Robert A.

153

Evaluation of the effects of agricultural conservation practices on sediment yield in the Colusa Basin, California  

NASA Astrophysics Data System (ADS)

The Soil and Water Assessment Tool (SWAT) was used to assess the impact of agricultural best management practices (BMPs) on sediment runoff from almond orchards in the lower Colusa Basin Drain watershed in the Sacramento Valley, California. This study used modeling techniques that include varying hydrologic parameters for both upland areas and small channels to quantify the effects of BMPs water quality. The BMPs simulated in this study are commonly used in almond orchards and include strip cropping, cover cropping, vegetative filter strips, grassed waterways and channel stabilization. The effectiveness of each BMP was simulated for an above average, below average and average rainfall year. Comparison of annual total watershed sediment loads for each BMP simulation showed that overall, channel stabilization and grassed waterways, which target in stream sediment erosion and transport, are the most effective BMPs with an estimated respective reduction in sediment load of 18% and 35% for a below average precipitation year, 13% and 26% for an above average precipitation year, and 17% and 30% for an average precipitation year. Simulations of BMPs designed to reduce sediment transport in upland areas, which include strip cropping and vegetative filter strips, estimated a reduction in total annual sediment load of less than 1% at the watershed outlet. These results indicated that in-stream sediment transport is the dominant sediment transport process in this watershed. Implementation of channel stabilization measures or grassed waterways on almond orchards is estimated to result in an annual reduction of total sediment load of 41,874 kg or 72,753 kg of sediment per square kilometer of almond orchard for an above average precipitation year.

Gatzke, S. E.; Zhang, M.

2009-12-01

154

Long-term runoff and sediment yields from small semiarid watersheds in southern Arizona  

Microsoft Academic Search

This study presents analysis of 34 years of precipitation, runoff, and sediment data collected from eight small (1.1–4.0 ha) semiarid rangeland watersheds in southern Arizona, USA. Average annual precipitation ranged between 354 and 458 mm with 53% of the total rainfall occurring from July through September. Runoff depth was 3.5%–13.9% of annual precipitation depth for individual watersheds and 9.2% on

V. O. Polyakov; M. A. Nearing; M. H. Nichols; R. L. Scott; J. J. Stone; M. P. McClaran

2010-01-01

155

The Eighth Annual NASA/Contractors Conference and 1991 National Symposium on Quality and Productivity: Extending the boundaries of total quality management  

NASA Technical Reports Server (NTRS)

The Eighth Annual NASA/Contractors Conference and 1991 National Symposium on Quality and Productivity provided a forum to exchange knowledge and experiences in these areas of continuous improvement. The more than 1,100 attendees from government, industry, academia, community groups, and the international arena had a chance to learn about methods, tools, and strategies for excellence and to discuss continuous improvement strategies, successes, and failures. This event, linked via satellite to concurrent conferences hosted by the NASA Goddard Space Flight Center in Greenbelt, Maryland, and Martin Marietta Astronautics Group in Denver, Colorado, also explored extending the boundaries of Total Quality Management to include partnerships for quality within communities and encouraged examination, evaluation, and change to incorporate the principles of continuous improvement.

Templeton, Geoffrey B. (editor); Stewart, Lynne M. (editor); Still, William T. (editor)

1992-01-01

156

Long-term runoff and sediment yields from small semi-arid watersheds in southern Arizona  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study presents analysis of 34 years of precipitation, runoff and sediment data collected from 8 small (1.1 to 4.0 ha) semi-arid rangeland watersheds in southern Arizona, USA. Average annual precipitation ranged between 354 mm and 458 mm with 53% of the total rainfall occurring from July throug...

157

Fluvial sediment in Ohio  

USGS Publications Warehouse

Characteristics of fluvial sediment in Ohio streams and estimates of sediment yield are reported. Results are based on data from several daily record stations and 5 years of intermittent record from a 38-station network. Most of the sediment transported by Ohio streams is in suspension. Mean annual bedload discharge, in percentage of mean annual suspended-sediment discharge, is estimated to be less than 10 percent at all but one of the sediment stations analyzed. Duration analysis shows that about 90 percent of the suspended sediment is discharged during 10 percent of the time. Concentration of suspended sediment averages less than 100 milligrams per liter 75 percent of the time and less than 50 milligrams per liter 50 percent of the time. Suspended sediment in Ohio streams is composed mostly of silt and clay. Sand particle content ranges from 1 to 2 percent in northwestern Ohio to 15 percent in the east and southeast. Sediment yields range from less than 100 tons per square mile per year (35 tonnes per square kilometer per year) in the northwest corner of Ohio to over 500 tons per square mile per year (17,5 tonnes per square kilometer per year) in the southern part, in Todd Fork basin, lower Paint Creek basin, and the Kentucky Bluegrass area. Yield from about 63 percent of Ohio's land area ranges from 100 to 200 tons per square mile per year (35 to 70 tonnes per square kilometer per year).

Anttila, Peter W.; Tobin, Robert L.

1978-01-01

158

Fluvial sedimentation in Kentucky  

USGS Publications Warehouse

Covering periods 1942-45 and 1951-81, this report documents the characteristics of sediments being transported from 79 drainage areas within the Commonwealth of Kentucky, and from eight stations on the main stem of the Ohio River. The drainage areas range in size from 0.67 square mile at Cane Branch near Parkers Lake to 40,330 square miles at Tennessee River near Paducah. Sediment yields and particle size of suspended and bed sediments are discussed by physiographic province. The Blue Grass had the highest average annual suspended-sediment yield for selected stations of 741 tons per square mile, and the Western Coal Field had the lowest with 197. The Eastern Coal Field had the broadest range of annual suspended-sediment yields. The range was from 25 tons per square mile at Helton Branch near Greenwood to 21,000 tons per square mile at Millers Creek near Phyllis. For selected stations bedload discharge was estimated to be 5 to 10 percent as much as the suspended-sediment discharge. Only three drainage areas had sediment yields that exceeded the average annual erosion rates for cultivated land in Kentucky of 9.93 tons per acre (6,355 tons per square mile). These three were in the Eastern Coal Field. (USGS)

Flint, R.F.

1983-01-01

159

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

NASA Astrophysics Data System (ADS)

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

Ismail, W. R.; Hashim, M.

2015-03-01

160

Fate of metals in coastal sediments of a Mediterranean flood-dominated system: An approach based on total and labile fractions  

NASA Astrophysics Data System (ADS)

The dynamics of sediment-bound metals (Cs, Cu, Ni, Pb, Ti and Zn) were studied off the Têt River (western Gulf of Lion), a typical Mediterranean coastal river punctuated by short and violent flash-floods. Spatial and temporal sampling strategies were combined to elucidate the fate of these elements in response to both the riverine sediment input and the offshore transport of these sediments through hydrodynamics. Our results show the temporal entrapment of riverborne particles and associated metals, consecutively to a major flood event, in the nearshore sedimentary unit called prodelta. Here, deposition and resuspension mechanisms define a sedimentological cycle that could be followed completely in this study. In terms of speciation between reactive (labile) and residual fractions along the fluvio-deltaic continuum, our results show that Cu, Pb and Zn are the most labile (potentially mobile) metals in the river, in accordance with their contributions from anthropogenic sources. But in the marine surficial sediments, two main behaviours can be discriminated when compared to the riverine suspended particulate matter. While Pb and Zn depict rather a constant labile fraction, Cu is characterized by decreasing levels (up to 50% difference). In terms of environmental impact, these contrasting trends have direct repercussions for the contaminant dispersal in the coastal area. Whereas Pb and Zn conserve their enhanced levels because of their stronger affinity with fine sediments, Cu is marked by the entire loss of its anthropogenic component that is progressively transferred to the dissolved phase, likely mediated by organic ligands. We ascribe these behaviours to different post-depositional partition mechanisms with respect to oxidation of the particulate organic phase at the bottom sediment/water interface. Also, analysis of one sediment core from the prodelta indicates that these early diagenetic processes govern the chemical forms of land-derived contaminants sequestrated in the nearshore sedimentary archives.

Roussiez, Vincent; Ludwig, Wolfgang; Radakovitch, Olivier; Probst, Jean-Luc; Monaco, André; Charrière, Bruno; Buscail, Roselyne

2011-05-01

161

The role of two sediment-dwelling invertebrates on the mercury transfer from sediments to the estuarine trophic web  

NASA Astrophysics Data System (ADS)

The annual total and organic mercury bioaccumulation pattern of Scrobicularia plana and Hediste diversicolor was assessed to evaluate the potential mercury transfer from contaminated sediments to estuarine food webs. S. plana was found to accumulate more total and organic mercury than H. diversicolor, up to 0.79 mg kg -1 and 0.15 mg kg -1 (wet weight) respectively, with a maximum annual uptake of 0.21 mg kg -1 y -1, while for methylmercury the annual accumulation was similar between species and never exceeded 0.045 mg kg -1 y -1. The higher organic mercury fraction in H. diversicolor is related to the omnivorous diet of this species. Both species increase methylmercury exposure by burrowing activities and uptake in anoxic, methylmercury rich sediment layers. Integration with the annual biological production of each species revealed mercury incorporation rates that reached 28 ?g m -2 y -1, and to extract as much as 11.5 g Hg y -1 (of which 95% associated with S. plana) in the 0.4 km 2 of the most contaminated area, that can be transferred to higher trophic levels. S. plana is therefore an essential vector in the mercury biomagnification processes, through uptake from contaminated sediments and, by predation, to transfer it to economically important and exploited estuarine species.

Coelho, J. P.; Nunes, M.; Dolbeth, M.; Pereira, M. E.; Duarte, A. C.; Pardal, M. A.

2008-07-01

162

Estimates of Sediment Load Prior to Dam Removal in the Elwha River, Clallam County, Washington  

USGS Publications Warehouse

Years after the removal of the two dams on the Elwha River, the geomorphology and habitat of the lower river will be substantially influenced by the sediment load of the free-flowing river. To estimate the suspended-sediment load prior to removal of the dams, the U.S. Geological Survey collected suspended-sediment samples during water years 2006 and 2007 at streamflow-gaging stations on the Elwha River upstream of Lake Mills and downstream of Glines Canyon Dam at McDonald Bridge. At the gaging station upstream of Lake Mills, discrete samples of suspended sediment were collected over a range of streamflows including a large peak in November 2006 when suspended-sediment concentrations exceeded 7,000 milligrams per liter, the highest concentrations recorded on the river. Based on field measurements in this study and from previous years, regression equations were developed for estimating suspended-sediment and bedload discharge as a function of streamflow. Using a flow duration approach, the average total annual sediment load at the gaging station upstream of Lake Mills was estimated at 327,000 megagrams with a range of uncertainty of +57 to -34 percent (217,000-513,000 megagrams) at the 95 percent confidence level; 77 percent of the total was suspended-sediment load and 23 percent was bedload. At the McDonald Bridge gaging station, daily suspended-sediment samples were obtained using an automated pump sampler, and concentrations were combined with the record of streamflow to calculate daily, monthly, and annual suspended-sediment loads. In water year 2006, an annual suspended-sediment load of 49,300 megagrams was determined at the gaging station at McDonald Bridge, and a load of 186,000 megagrams was determined upstream at the gaging station upstream of Lake Mills. In water year 2007, the suspended-sediment load was 75,200 megagrams at McDonald Bridge and 233,000 megagrams upstream of Lake Mills. The large difference between suspended-sediment loads at both gaging stations shows the extent of sediment trapping by Lake Mills, and a trap efficiency of 0.86 was determined for the reservoir. Pre-dam-removal estimates of suspended-sediment load and sediment-discharge relations will help planners monitor geomorphic and habitat changes in the river as it reaches a dynamic equilibrium following the removal of dams.

Curran, Christopher A.; Konrad, Christopher P.; Higgins, Johnna L.; Bryant, Mark K.

2009-01-01

163

Simultaneously Extracted Metals/Acid-Volatile Sulfide and Total Metals in Surface Sediment from the Hanford Reach of the Columbia RIver and the Lower Snake River  

SciTech Connect

Metals have been identified as contaminants of concern for the Hanford Reach because of upriver mining, industrial activities, and past nuclear material production at the US Department of Energy's Hanford Site. This study was undertaken to better understand the occurrence and fate of metals in sediment disposition areas in the Columbia and Snake Rivers.

Patton, Gregory W.; Crecelius, Eric A.

2001-01-24

164

Two periods of total testicular regression are peculiar events of the annual reproductive cycle of the black Myotis bat, Myotis nigricans (Chiroptera: Vespertilionidae).  

PubMed

Myotis nigricans presents few and controversial reproductive data, which indicate geographical variation in reproduction. Thus, this study aimed to evaluate the seasonal modifications in testicular and epididymal morphologies in a tropical environment, submitting these organs to morphometric and immunohistochemical analysis. The observations revealed that this species presents two peaks of spermatogenic activity followed by two periods of total testicular regression (a quiescent pre-pubertal-like morphology, where only Sertoli cells and spermatogonia could be observed), in the same annual reproductive cycle, which seem to be only indirectly influenced by abiotic factors. This testicular behaviour seems to be synchronised with the caput and corpus epididymidis, but not with the cauda epididymidis, which presents aspects of sperm storage in May-June. The control of this variation seems to be directly linked to the expression of the androgen receptor, since, throughout the year, it is high in periods of testicular recrudescence and low in periods of deactivation. It is not thought to be directly linked to apoptosis, which is more pronounced in periods of recrudescence than in periods of regression. PMID:23830483

Beguelini, Mateus R; Góes, Rejane M; Taboga, Sebastião R; Morielle-Versute, Eliana

2014-01-01

165

Large-scale quantification of suspended sediment transport and deposition in the Mekong Delta  

NASA Astrophysics Data System (ADS)

Sediment dynamics play a major role for the agricultural and fishery productivity of the Mekong Delta. However, the understanding of sediment dynamics in the Mekong Delta, one of the most complex river deltas in the world, is very limited. This is a consequence of its large extent, the intricate system of rivers, channels and floodplains and the scarcity of observations. This study quantifies, for the first time, the suspended sediment transport and sediment-nutrient deposition in the whole Mekong Delta. To this end, a quasi-2-D hydrodynamic model is combined with a cohesive sediment transport model. The combined model is calibrated automatically using six objective functions to represent the different aspects of the hydraulic and sediment transport components. The model is calibrated for the extreme flood season in 2011 and shows good performance for the two validation years with very different flood characteristics. It is shown how sediment transport and sediment deposition vary from Kratie at the entrance of the Delta to the coast. The main factors influencing the spatial sediment dynamics are the setup of rivers, channels and dike-rings, the sluice gate operations, the magnitude of the floods and tidal influences. The superposition of these factors leads to high spatial variability of sediment transport, in particular in the Vietnamese floodplains. Depending on the flood magnitude, the annual sedimentation rate averaged over the Vietnamese floodplains varies from 0.3 to 2.1 kg m-2 yr-1, and the ring dike floodplains trap between 1 and 6% of the total sediment load at Kratie. This is equivalent to 29 × 103-440 × 103 t of nutrients (N, P, K, TOC) deposited in the Vietnamese floodplains. This large-scale quantification provides a basis for estimating the benefits of the annual Mekong floods for agriculture and fishery, and is important information for assessing the effects of deltaic subsidence and climate change related sea level rise.

Manh, N. V.; Dung, N. V.; Hung, N. N.; Merz, B.; Apel, H.

2014-04-01

166

SEDIMENT REMOVAL  

EPA Science Inventory

When properly conducted, sediment removal is an effective lake management technique. This chapter describes: (1) purposes of sediment removal, (2) environmental concerns, (3) appropriate depth of sediment removal, (4) sediment removal techniques, (5) suitable lake conditions, (6)...

167

Sediment discharge in the Santa Clara River Basin, Ventura and Los Angeles Counties, California  

USGS Publications Warehouse

Sediment data collected in the Santa Clara River in California basin, during the 1967-75 water years were analyzed to determine the particle size and quantity of sediment transported past three gaging stations. The total sediment discharge of the basin , computed from records of Santa Clara River at Montalvo for water years 1968-75, was 63.5 million tons, of which 59.5 million tons was carried in suspension and an estimated 4 million tons was transported as unsampled sediment discharge. About 17.7 million tons, or 28 percent of the total sediment discharge, was coarse sediment (particles larger than 0.062 millimeter). Most of the sediment was transported during only a few days of floodflow each year. During the 1968-75 water years, approximately 55 percent of the total sediment was transported in 2 days and 92 percent was transported in 53 days. The long-term (1928-75) average annual sediment discharge of the Santa Clara River at Montalvo is estimated at 3.67 million tons. Of that quantity, 2.58 million tons consisted of fine sediment and 1.09 million tons consisted of coarse sediment. A sediment budget for the Santa Clara River basin was estimated for sediment discharges under both natural and actual conditions. The major difference between natural and actual sediment discharges of the Santa Clara River basin is the sediment intercepted upstream from Lake Piru. The combined trap efficiency of Lake Piru and Pyramid Lake approaches 100 percent. Sediment deposited in these reservoirs resulted in about a 6-percent reduction of sediment to the Santa Clara River basin during the historical period (1928-75) and a 12-percent reduction during the period most affected by dams (1953-75). Sediment losses to the basin by gravel mining, diversion of flows, and interception of sediment in the Castaic Creek basin resulted in additional reductions of 2 percent during the period 1928-75 and 4 percent during the period 1953-75. (Kosco-USGS)

Williams, Rhea P.

1979-01-01

168

Total Mercury, Methylmercury, Methylmercury Production Potential, and Ancillary Streambed-Sediment and Pore-Water Data for Selected Streams in Oregon, Wisconsin, and Florida, 2003-04  

USGS Publications Warehouse

Mercury contamination of aquatic ecosystems is an issue of national concern, affecting both wildlife and human health. Detailed information on mercury cycling and food-web bioaccumulation in stream settings and the factors that control these processes is currently limited. In response, the U.S. Geological Survey (USGS) National Water-Quality Assessment Program (NAWQA) conducted detailed studies from 2002 to 2006 on various media to enhance process-level understanding of mercury contamination, biogeochemical cycling, and trophic transfer. Eight streams were sampled for this study: two streams in Oregon, and three streams each in Wisconsin and Florida. Streambed-sediment and pore-water samples were collected between February 2003 and September 2004. This report summarizes the suite of geochemical and microbial constituents measured, the analytical methods used, and provides the raw data in electronic form for both bed-sediment and pore-water media associated with this study.

Marvin-DiPasquale, Mark C.; Lutz, Michelle A.; Krabbenhoft, David P.; Aiken, George R.; Orem, William H.; Hall, Britt D.; DeWild, John F.; Brigham, Mark E.

2008-01-01

169

Assessment of hydrology, sediment and particulate organic carbon yield in a large agricultural catchment using the SWAT model  

NASA Astrophysics Data System (ADS)

SummaryThe Soil and Water Assessment Tool (SWAT, 2005) was used to simulate discharge and sediment transport at daily time steps within the intensively farmed Save catchment in south-west France (1110 km 2). The SWAT model was applied to evaluate catchment hydrology and sediment and associated particulate organic carbon yield using historical flow and meteorological data for a 10-years (January 1999-March 2009). Daily data on sediment (27 months, January 2007-March 2009) and particular organic carbon (15 months, January 2008-March 2009) were used to calibrate the model. Data on management practices (crop rotation, planting date, fertiliser quantity and irrigation) were included in the model during the simulation period of 10 years. Simulated daily discharge, sediment and particulate carbon values matched the observed values satisfactorily. The model predicted that mean annual catchment precipitation for the total study period (726 mm) was partitioned into evapotranspiration (78.3%), percolation/groundwater recharge (14.1%) and abstraction losses (0.5%), yielding 7.1% surface runoff. Simulated mean total water yield for the whole simulation period amounted to 138 mm, comparable to the observed value of 136 mm. Simulated annual sediment yield ranged from 4.3 t km -2 y -1 to 110 t km -2 y -1 (annual mean of 48 t km -2 y -1). Annual yield of particulate organic carbon ranged from 0.1 t km -2 y -1 to 2.8 t km -2 y -1 (annual mean of 1.2 t km -2 y -1). Thus, the highest annual sediment and particulate carbon yield represented 25 times the minimum annual yield. However, the highest annual water yield represented five times the minimum (222 mm and 51 mm, respectively). An empirical correlation between annual water yield and annual sediment and organic carbon yield was developed for this agricultural catchment. Potential source areas of erosion were also identified with the model. The range of the annual contributing erosive zones varied spatially from 0.1 to 6 t ha -1 according to the slope and agricultural practices at the catchment scale.

Oeurng, Chantha; Sauvage, Sabine; Sánchez-Pérez, José-Miguel

2011-05-01

170

Monitoring urban impacts on suspended sediment, trace element, and nutrient fluxes within the City of Atlanta, Georgia, USA: Program design, methodological considerations, and initial results  

USGS Publications Warehouse

Atlanta, Georgia (City of Atlanta, COA), is one of the most rapidly growing urban areas in the US. Beginning in 2003, the US Geological Survey established a long-term water-quantity/quality monitoring network for the COA. The results obtained during the first 2 years have provided insights into the requirements needed to determine the extent of urban impacts on water quality, especially in terms of estimating the annual fluxes of suspended sediment, trace/major elements, and nutrients. During 2004/2005, suspended sediment fluxes from the City of Atlanta (COA) amounted to about 150 000 t year-1; ??? 94% of the transport occurred in conjunction with storm-flow, which also accounted for ??? 65% of the annual discharge. Typically, storm-flow averaged ??? 20% of theyear. Normally, annual suspended sediment fluxes are determined by summing daily loads based on a single calculation step using mean-daily discharge and a single rating curve-derived suspended sediment concentration. Due to the small and 'flashy' nature of the COAs streams, this approach could produce underestimates ranging from 25% to 64%. Accurate estimates (?? 15%) require calculation time-steps as short as every 2-3 h. Based on annual median base-flow/storm-flow chemical concentrations, the annual fluxes of ??? 75% of trace elements (e.g. Cu, Pb, Zn), major elements (e.g. Fe, Al), and total P occur in association with suspended sediment; in turn, ??? 90% of the transport of these constituents occur in conjunction with storm-flow. As such, base-flow sediment-associated and dissolved contributions represent relatively insignificant portions of the total annual load. An exception is total N, whose sediment-associated fluxes range from 50% to 60%; even so, storm-related transport typically exceeds 80%. Hence, in urban environments, non-point-source appear to be the dominant contributors to the fluxes of these constituents.

Horowitz, A.J.; Elrick, K.A.; Smith, J.J.

2008-01-01

171

Estimates of suspended sediment entering San Francisco Bay from the Sacramento and San Joaquin Delta, San Francisco Bay, California  

USGS Publications Warehouse

This study demonstrates the use of suspended-sediment concentration (SSC) data collected at Mallard Island as a means of determining suspended-sediment load entering San Francisco Bay from the Sacramento and San Joaquin River watersheds. Optical backscatter (OBS) data were collected every 15 min during water years (WYs) 1995-2003 and converted to SSC. Daily fluvial advective sediment load was estimated by combining estimated Delta outflow with daily averaged SSC. On days when no data were available, SSC was estimated using linear interpolation. A model was developed to estimate the landward dispersive load using velocity and SSC data collected during WYs 1994 and 1996. The advective and dispersive loads were summed to estimate the total load. Annual suspended-sediment load at Mallard Island averaged 1.2??0.4 Mt (million metric tonnes). Given that the average water discharge for the 1995-2003 period was greater than the long -term average discharge, it seems likely that the average suspended-sediment load may be less than 1.2??0.4 Mt. Average landward dispersive load was 0.24 Mt/yr, 20% of the total. On average during the wet season, 88% of the annual suspended-sediment load was discharged through the Delta and 43% occurred during the wettest 30-day period. The January 1997 flood transported 1.2 Mt of suspended sediment or about 11% of the total 9-year load (10.9 Mt). Previous estimates of sediment load at Mallard Island are about a factor of 3 greater because they lacked data downstream from riverine gages and sediment load has decreased. Decreasing suspended-sediment loads may increase erosion in the Bay, help to cause remobilization of buried contaminants, and reduce the supply of sediment for restoration projects. ?? 2005 Elsevier B.V. All rights reserved.

McKee, L.J.; Ganju, N.K.; Schoellhamer, D.H.

2006-01-01

172

Modeling the influence of river rehabilitation scenarios on bed material sediment flux in a large river over decadal timescales  

USGS Publications Warehouse

A stochastic flood generator and calibrated sediment transport formulae were used to assess the decadal impact of major river rehabilitation strategies on two fraction bed material sediment flux and net storage, first-order indicators of aquatic riverine habitat, in a large river system. Model boundary conditions were modified to reflect the implementation of three major river rehabilitation strategies being considered in the Sacramento River Valley: gravel augmentation, setting back of levees, and flow alteration. Fifty 30-year model simulations were used to compute probabilities of the response in sediment flux and net storage to these strategies. Total annual average bed material sediment flux estimates were made at six gauged river cross sections, and ???60 km reach-scale sediment budgets were evaluated between them. Gravel augmentation to improve spawning habitat induced gravel accumulation locally and/or downstream, depending on the added mixture. Levee setbacks to recreate the river corridor reduced flow stages for most flows and hence lowered sediment flux. Flow alteration to mimic natural flow regimes systematically decreased total annual average flux, suggesting that high-magnitude low-frequency transport events do not affect long-term trends in bed material flux. The results indicate that each rehabilitation strategy reduces sediment transport in its target reaches and modulates imbalances in total annual bed material sediment budgets at the reach scale. Additional risk analysis is necessary to identify extreme conditions associated with variable hydrology that could affect rehabilitation over decades. Sensitivity analysis suggests that sorting of bed material sediment is the most important determinant of modeled transport and storage patterns. Copyright 2006 by the American Geophysical Union.

Singer, M.B.; Dunne, T.

2006-01-01

173

Cruise Report 2005 RMP Sediment Report  

E-print Network

Cruise Report 2005 RMP Sediment Report August 23-30, 2005 A P P L I E D S C I E N C E S #12;2005 RMP Sediment Cruise Report August 23 - 30, 2005 Applied Marine Sciences, Inc. Page 2 1.0 INTRODUCTION Francisco Estuary (RMP) annual sediment cruise. The cruise was redesigned in 2002 to adopt a randomized

174

A Kinetic Model To Quantify The Effect Of Total Organic Carbon Content On The Loss Of Magnetic Susceptibility Values In Surficial Sediments Of Coastal Environments: The Case Study Of The Ría De Muros, NW Spain  

NASA Astrophysics Data System (ADS)

A detailed magnetic study of mineral dissolution has been carried out in surficial sediments from the Ría de Muros, a large coastal embayment in NW Iberia. The study area is under the influence of one of the world's most intense coastal upwelling systems, which along with the important continental supplies of organic carbon, cause very high organic matter contents in the sediment. The magnetic susceptibility of the surficial (top 20 cm of the sea bed) sediments of the Ría de Muros is dominated by the occurrence of ferromagnetic minerals, mostly biogenic magnetite and detrital (titano-) magnetite. The way in which the Total Organic Carbon (TOC) in the sediment controls the occurrence and concentration of these minerals is twofold. First because a minimal amount of organic matter it is needed for the development of the magnetotactic bacteria. Second because values above a given TOC concentration promote early redoxomorfic diagenesis and subsequently, ferromagnetic minerals depletion by dissolution. Maximum magnetic susceptibility values (up to 7 x 10-8 SI) are subsequently found in sediments with enough supply of organic matter to ensure the growth of magnetotactic bacteria, but where the TOC content is not as high as to cause the development of suboxic conditions within the surficial layers of the sediments. The magnetic susceptibility loss due to the increase in TOC can be explained and quantified with a simple geochemical kinetic model. Textural dilution of the magnetic signal due to the presence of coarse diamagnetic quartz and biogenic carbonates in the sediment matrix, are accounted for by normalizing with Al, a well-know grain-size proxy in this environment. When the normalized magnetic susceptibility is plotted against the TOC, the resulting distribution shows a neat exponential decay trend from high magnetic susceptibility and low TOC values to low magnetic susceptibility and high TOC values, resulting from the kinetics of magnetite dissolution. This profile is interpreted as a consequence of the microbial degradation of organic matter that occurs in muddy or muddy sandy ría sediments, where the TOC availability is not a limiting factor due to the high organic matter concentrations (2 to 10%). On the contrary, the process appears to be limited by the availability of electron acceptors and, as a result, suboxic conditions are achieved at very shallow depths. Considering this, we propose a simple second order kinetic model for the dissolution of magnetite in which the rate of dissolution of magnetite depends on the TOC and magnetite concentrations of the sediment. The resulting model explains the exponential profile of magnetic susceptibility versus TOC with a significance level of p<0.01 (r2=0.98). From the parameters of this model, it is possible to estimate that an increase of 0.35±0.05% in the sedimentary TOC is able to reduce by half the magnetite concentration in the sediments of this ría.

Andrade, A.; Rey, D.; Mohamed, K. J.; Rubio, B.

2013-05-01

175

Annual dissolved nitrite plus nitrate and total phosphorous loads for the Susquehanna, St. Lawrence, Mississippi-Atchafalaya, and Columbia River basins, 1968-2004  

USGS Publications Warehouse

Annual stream-water loads were calculated near the outlet of four of the larger river basins (Susquehanna, St. Lawrence, Mississippi-Atchafalaya, and Columbia) in the United States for dissolved nitrite plus nitrate (NO2 + NO3) and total phosphorus using LOADEST load estimation software. Loads were estimated for the period 1968-2004; although loads estimated for individual river basins and chemical constituent combinations typically were for shorter time periods due to limitations in data availability. Stream discharge and water-quality data for load estimates were obtained from the U.S. Geological Survey (USGS) with additional stream discharge data for the Mississippi-Atchafalaya River Basin from the U.S. Army Corps of Engineers. The loads were estimated to support national assessments of changes in stream nutrient loads that are periodically conducted by Federal agencies (for example, U.S. Environmental Protection Agency) and other water- and land-resource organizations. Data, methods, and results of load estimates are summarized herein; including World Wide Web links to electronic ASCII text files containing the raw data. The load estimates are compared to dissolved NO2 + NO3 loads for three of the large river basins from 1971 to 1998 that the USGS provided during 2001 to The H. John Heinz III Center for Science, Economics and the Environment (The Heinz Center) for a report The Heinz Center published during 2002. Differences in the load estimates are the result of using the most up-to-date monitoring data since the 2001 analysis, differences in how concentrations less than the reporting limit were handled by the load estimation models, and some errors and exclusions in the 2001 analysis datasets (which resulted in some inaccurate load estimates).

Aulenbach, Brent T.

2006-01-01

176

Sediment dynamics in the restored reach of the Kissimmee River Basin, Florida: A vast subtropical riparian wetland  

USGS Publications Warehouse

Historically, the Kissimmee River Basin consisted of a broad nearly annually inundated riparian wetland similar in character to tropical Southern Hemisphere large rivers. The river was channelized in the 1960s and 1970s, draining the wetland. The river is currently being restored with over 10?000 hectares of wetlands being reconnected to 70 river km of naturalized channel. We monitored riparian wetland sediment dynamics between 2007 and 2010 at 87 sites in the restored reach and 14 sites in an unrestored reference reach. Discharge and sediment transport were measured at the downstream end of the restored reach. There were three flooding events during the study, two as annual flood events and a third as a greater than a 5-year flood event. Restoration has returned periodic flood flow to the riparian wetland and provides a mean sedimentation rate of 11.3?mm per year over the study period in the restored reach compared with 1.7?mm per year in an unrestored channelized reach. Sedimentation from the two annual floods was within the normal range for alluvial Coastal Plain rivers. Sediment deposits consisted of over 20% organics, similar to eastern blackwater rivers. The Kissimmee River is unique in North America for its hybrid alluvial/blackwater nature. Fluvial suspended-sediment measurements for the three flood events indicate that a majority of the sediment (70%) was sand, which is important for natural levee construction. Of the total suspended sediment load for the three flood events, 3%–16% was organic and important in floodplain deposition. Sediment yield is similar to low-gradient rivers draining to the Chesapeake Bay and alluvial rivers of the southeastern USA. Continued monitoring should determine whether observed sediment transport and floodplain deposition rates are normal for this river and determine the relationship between historic vegetation community restoration, hydroperiod restoration, and sedimentation.

Schenk, E.R.; Hupp, C.R.; Gellis, A.

2012-01-01

177

Evaluation of high-pressure microwave digestion methods for hydride generation atomic absorption spectrometric determination of total selenium and arsenic in sediment  

Microsoft Academic Search

Five closed-vessel microwave digestion methods were compared for the accurate determination of arsenic and selenium in NIST SRM 1645 River Sediment by flow-injection hydride-generation atomic absorption spectrometric methods. The digestion methods using five different acid mixtures (HNO3\\/ H2SO4, HNO3\\/HCl04, HNO3\\/HCl, HNO3\\/HCl\\/HF, HNO3\\/H2SO4\\/HClO4) were all found to be reliable for the determination of the analytes. Taking into consideration the safety and

Chao Yan Zhou; Ming Keong Wong; Lip Lin Koh; Yeow Chin Wee

1997-01-01

178

Exchanges of sediment between the flood plain and channel of the Amazon River in Brazil  

USGS Publications Warehouse

Sediment transport through the Brazilian sector of the Amazon River valley, a distance of 2010 km, involves exchanges between the channel and the flood plain that in each direction exceed the annual flux of sediment out of the river at O??bidos (???1200 Mt yr-1). The exchanges occur through bank erosion, bar deposition, settling from diffuse overbank flow, and sedimentation in flood-plain channels. We estimated the magnitude of these exchanges for each of 10 reaches of the valley, and combined them with calculations of sediment transport into and out of the reaches based on sediment sampling and flow records to define a sediment budget for each reach. Residuals in the sediment budget of a reach include errors of estimation and erosion or deposition within the channel. The annual supply of sediment entering the channel from bank erosion was estimated to average 1570 Mt yr-1 (1.3 ?? the O??bidos flux) and the amount transferred from channel transport to the bars (380 Mt yr-1) and the flood plain (460 Mt yr-1 in channelized flow; 1230 Mt yr-1 in diffuse overbank flow) totaled 2070 Mt yr-1 (1.7 ?? the O??bidos flux). Thus, deposition on the bars and flood plain exceeded bank erosion by 500 Mt yr-1 over a 10-16 yr period. Sampling and calculation of sediment loads in the channel indicate a net accumulation in the valley floor of approximately 200 Mt yr-1 over 16 yr, crudely validating the process-based calculations of the sediment budget, which in turn illuminate the physical controls on each exchange process. Another 300-400 Mt yr-1 are deposited in a delta plain downstream of O??bidos. The components of the sediment budget reflect hydrologie characteristics of the valley floor and geomorphic characteristics of the channel and flood plain, which in turn are influenced by tectonic features of the Amazon structural trough.

Dunne, T.; Mertes, L.A.K.; Meade, R.H.; Richey, J.E.; Forsberg, B.R.

1998-01-01

179

24 CFR 884.104 - Maximum total annual contract commitment and project account (private-owner or PHA-owner projects).  

Code of Federal Regulations, 2010 CFR

...equal to 40 percent of such maximum annual Contract commitment, HUD shall, within a reasonable period of time, take such additional steps authorized by Section 8(c)(6) of the Act as may be necessary to carry out this assurance,...

2010-04-01

180

Large-scale dam removal on the Elwha River, Washington, USA: fluvial sediment load  

USGS Publications Warehouse

The Elwha River restoration project, in Washington State, includes the largest dam-removal project in United States history to date. Starting September 2011, two nearly century-old dams that collectively contained 21 ± 3 million m3 of sediment were removed over the course of three years with a top-down deconstruction strategy designed to meter the release of a portion of the dam-trapped sediment. Gauging with sediment-surrogate technologies during the first two years downstream from the project measured 8,200,000 ± 3,400,000 tonnes of transported sediment, with 1,100,000 and 7,100,000 t moving in years 1 and 2, respectively, representing 3 and 20 times the Elwha River annual sediment load of 340,000 ± 80,000 t/y. During the study period, the discharge in the Elwha River was greater than normal (107% in year 1 and 108% in year 2); however, the magnitudes of the peak-flow events during the study period were relatively benign with the largest discharge of 292 m3/s (73% of the 2-year annual peak-flow event) early in the project when both extant reservoirs still retained sediment. Despite the muted peak flows, sediment transport was large, with measured suspended-sediment concentrations during the study period ranging from 44 to 16,300 mg/L and gauged bedload transport as large as 24,700 t/d. Five distinct sediment-release periods were identified when sediment loads were notably increased (when lateral erosion in the former reservoirs was active) or reduced (when reservoir retention or seasonal low flows and cessation of lateral erosion reduced sediment transport). Total suspended-sediment load was 930,000 t in year 1 and 5,400,000 t in year 2. Of the total 6,300,000 ± 3,200,000 t of suspended-sediment load, 3,400,000 t consisted of silt and clay and 2,900,000 t was sand. Gauged bedload on the lower Elwha River in year 2 of the project was 450,000 ± 360,000 t. Bedload was not quantified in year 1, but qualitative observations using bedload-surrogate instruments indicated detectable bedload starting just after full removal of the downstream dam. Using comparative studies from other sediment-laden rivers, the total ungauged fraction of < 2-mm bedload was estimated to be on the order of 1.5 Mt.

Magirl, Christopher S.; Hilldale, Robert C.; Curran, Christopher A.; Duda, Jeffrey J.; Straub, Timothy D.; Domanski, Marian M.; Foreman, James R.

2014-01-01

181

Sediment discharge in the Lake Tahoe basin, California, 1972 water year  

USGS Publications Warehouse

Streamflow and fluvial-sediment discharge data are being collected at selected streams and highway gutters in the Lake Tahoe basin to determine the extent of erosion from highway cuts and to evaluate the effects of various land treatment practices to reduce erosion. Precipitation in the Lake Tahoe area during 1972 was 77 percent of normal; consequently, runoff was well below normal. Seventy-six percent of the total annual runoff during the 1972 water year occurred from March through June 1972. Sediment samples were collected during the year at streamflow gaging stations and at gutter stations at highway cuts to define the range of transport conditions. The major part (87 percent) of the annual suspended-sediment discharge during the 1972 water year occurred during the snowmelt runoff period, March through June.

Kroll, Carl G.

1973-01-01

182

Accumulations of total metal in dominant shrimp species (Palaemon adspersus, Palaemon serratus, Parapenaeus longirostris) and bottom surface sediments obtained from the Northern Inner Shelf of the Sea of Marmara.  

PubMed

The aim of this study is to determine the total metal (aluminum, copper, manganese, nickel, lead, zinc, cadmium, iron, mercury) contents of dominant shrimp species and sediments present at 1-50 m depths of the Northern Inner Shelf of the Sea of Marmara. Shrimp and sediment samples were collected from four regions (Büyükçekmece, Silivri, Tekirda?, Sarköy) and from different depths (1, 5, 10, 20, 30, 50 m) at each region in September and November of 2003. Three shrimp species [Palaemon adspersus (Rathke, 1937), Palaemon serratus (Pennant, 1777), Parapenaeus longirostris (H. Lucas, 1846)] were identified to be dominant as a result of the examination on the obtained samples. Heavy metal contents of these three species were determined and the results were compared with the acceptable treshold values of the Seafood Standards and also with available literatures. The Cu contents were found to be higher than the treshold limits in all samples except P. longirostris from Silivri, also the Cd contents in all samples except P. adspersus from Büyükçekmece, the Zn contents only in P. adspersus and P. longirostris from Tekirda?, and the Pb contents in all species from all regions. These high values are the indicator of industrial pollution. There is not any data in the Seafood Standards about Mn, Ni, Fe and Al contents in shrimp species. The values of these metal contents were given in the present study. The examination of total metal distributions in bottom surface sediment samples in the Northern Inner Shelf of the Sea of Marmara showed that the determined values were higher than the shale average at some depths of examined stations. PMID:17406997

Kurun, A; Balkis, H; Balkis, N

2007-12-01

183

Sediment resuspension, redeposition, and focusing in a small dimictic reservoir  

USGS Publications Warehouse

Rates of seston (dry mass) sedimentation, estimated from sediment traps (ST rates) and sediment cores (SC rates), were determined at four water depths to examine seasonal and annual sedimentation patterns in Eau Galle Reservoir, Wisconsin (USA). Annual ST rates overestimated annual SC rates at water depths less-than-or-equal-to 4 m, suggesting that sediment resuspension and redeposition in relatively shallow regions of the reservoir caused the overestimate. In contrast, annual ST and SC rates were similar at depths >4 m, suggesting minimal sediment resuspension and redeposition in deeper regions of the reservoir. Using variations in daily ST rates estimated during the autumn overturn of 1987, we developed a conceptual framework for estimating sediment resuspension, redeposition, and focusing. Resuspension of shallow sediments during this particular period accounted for over 50% of the annual ST rate at depths less-than-or-equal-to 4 m. At the same time, focusing of resuspended shallow sediments to deeper regions accounted for about 20% of the annual ST rate at depths >4 m. Our results indicate that during autumn overturn in this reservoir, peaks in sedimentation in the deep, profundal region, estimated from sediment traps, may reflect sediment focused from shallow regions rather than sediment resuspended from the profundal region.

James, W.F.; Barko, J.W.

1993-01-01

184

QUANTIFICATION AND INTERPRETATION OF TOTAL PETROLEUM HYDROCARBONS IN SEDIMENT SAMPLES BY A GC/MS METHOD AND COMPARISON WITH EPA 418.1 AND A RAPID FIELD METHOD  

EPA Science Inventory

ABSTRACT: Total Petroleum hydrocarbons (TPH) as a lumped parameter can be easily and rapidly measured or monitored. Despite interpretational problems, it has become an accepted regulatory benchmark used widely to evaluate the extent of petroleum product contamination. Three cu...

185

Multi-proxy analysis of annually laminated sediments from two neighboring lakes in South-Central Chile: a continuous activity record of Villarrica Volcano for the past 600 years  

NASA Astrophysics Data System (ADS)

Lake sediments contain valuable information about past volcanic and seismic events that affected the lake and its catchment, and provide unique records of the recurrence rate and magnitude of such events. This study uses a multi-lake and multi-proxy analytical approach to obtain reliable and high-resolution records of past natural catastrophes from c. 600 year old annually-laminated (varved) lake sediment sequences extracted from two lakes, Villarrica and Calafquén, in the volcanically and seismically active Chilean Lake District. Using a combination of µXRF scanning, microfacies analysis, grain-size analysis, color analysis and magnetic susceptibility, we detected and characterized four different types of event deposits (EDs) (lacustrine turbidites; tephra-fall layers; run-off cryptotephras; lahar deposits) and revised the eruption record for Villarrica Volcano, which is unprecedented in its continuity and temporal resolution. Moreover, lahar deposits in lacustrine sediments were described for the first time. Time series analysis shows 112 eruptions with a Volcanic Explosivity Index (VEI) ? 2 in the last c. 600 years. Also deposits of eruptions from the more remote Carrán-Los Venados Volcanic Complex, Mocho-Choshuenco, Quetrupillán and Lanín or Huanquihue volcanoes were identified in the studied lake sediments. The last VEI ? 2 eruption of Villarrica Volcano occurred in AD 1991. We estimate the probability of the occurrence of future eruptions from Villarrica Volcano, and statistically demonstrate that the probability of a 21-year repose period (anno 2012) without eruptions is ? 1.9 %. This new perspective on the recurrence interval of eruptions and historical lahar activity will help improve volcanic hazard assessments for this rapidly expanding tourist region.

Van Daele, Maarten; Moernaut, Jasper; Silversmit, Geert; Schmidt, Sabine; Fontijn, Karen; Heirman, Katrien; Vandoorne, Willem; De Clercq, Maikel; Van Acker, Joris; Wolff, Christian; Pino, Mario; Urrutia, Roberto; Roberts, Stephen J.; Vincze, Laszlo; De Batist, Marc

2013-04-01

186

Sediment source fingerprinting to quantify fine sediment sources in forested catchments, Chile.  

NASA Astrophysics Data System (ADS)

A study to improve the understanding of the primary sediment sources and transfer pathways in catchments disturbed following forest plantation harvesting is being undertaken in South-Central Chile. The study focuses on two sets of paired experimental catchments (treatment and control), located about 400 km apart, with similar soil type but contrasting mean annual rainfall: Nacimiento (1,200 mm year-1) and Los Ulmos (2,500 mm year-1). Sediment source fingerprinting techniques are being used to document the primary fine sediment sources. In each catchment, three potential sediment sources were defined: clearcut slopes (Z1), forest roads (Z2) and the stream channel (Z3). In each catchment, multiple representative composite samples of the different potential source materials were collected before harvest operations from the upper 1 cm layer in Z1, Z2, and from the channel bank and bed for Z3. A time-integrating trap sampler installed in the discharge monitoring station constructed at the outlet of each catchment has been used to collect samples of the suspended sediment and these have been supplemented by sediment collected from the weir pools. Total suspended sediment load is been quantified in the monitoring stations using discharge records and integrated water sampling. Caesium-137 (137Cs), excess lead-210 (210Pbex) and other sediment properties are being used as fingerprints. After air-drying, oven-drying at 40°C and disaggregation, both the source material samples and the sediment samples collected in the discharge monitoring stations were sieved through a 63-?m sieve and the <63-?m fractions were used for subsequent analyses. For radionuclide assay, the samples were sealed in Petri dishes and after 4 weeks the mass activity density (activity concentration) of 137Cs and 210Pbex was determined by gamma analysis, using an ORTEC extended range Ge detector of 53% relative efficiency. The 137Cs and 210Pbex activity and organic carbon (Corg) concentration associated with potential source materials and the target sediment show that the two radionuclides used in combination with the Corg property provide effective source fingerprints. Additional work using a mixing model taking account of particle size effects is required to establish the relative contributions of the three sources to the fine sediment loads of the study catchments. This research is supported by the Chilean Government through FONDECYT Project 1090574 and by the IAEA through CRP D1.20.11 (Contract CHI-15531 and Technical Contract 15478) and the RLA 05/051 Project.

Schuller, P.; Walling, D. E.; Iroume, A.; Castillo, A.; Quilodran, C.

2012-04-01

187

Fluvial sediment in Double Creek subwatershed No. 5, Washington County, Oklahoma  

USGS Publications Warehouse

Most precipitation falling on subwatershed No. 5 does not flow through the reservoir. During this study approximately three-fourths (47,000 acre-feet) of the precipitation was lost by evaporation and transpiration; a small amount is lost by deep subsurface percolation. Fifty-nine percent of the total sediment load was discharged from the reservoir during four major outflow periods representing 34 percent of the outflow days. The highest percentage of runoff and sediment yield occurs from March through June. Fifty-three percent of the water discharged and 63 percent of the sediment yield occurred during this 4-month period. The average annual yield of fluvial sediment from watershed No. 5 was 607 tons per square mile, or 0.95 ton per acre. A total of 21,370 tons of fluvial sediment was transported into reservoir No. 5 and a total of 19,930 tons was deposited. Seventy-eight percent of the total fluvial sediment was deposited during the first 9.2 years, or 63 percent of time of reservoir operation. The computed trap efficiency of reservoir No. 5 was 93 percent.

Bednar, Gene A.; Waldrep, T.E.

1973-01-01

188

Sediment Loading from Crab Creek and Other Sources to Moses Lake, Washington, 2007 and 2008  

USGS Publications Warehouse

The average sediment-accumulation rate on the bed of Moses Lake since 1980, based on the identification of Mount St. Helens ash in lakebed cores, was 0.24 inches per year. Summed over the lake surface area, the average sediment-accumulation rate on the lakebed is 190,000 tons per year. Based on USGS stream-gaging station data, the average annual sediment load to Moses Lake from Crab Creek was 32,000 tons per year between 1943 and 2008; the post Mount St. Helens eruption annual load from Crab Creek was calculated to be 13,000 tons per year. The total mass input from Crab Creek and other fluvially derived sediment sources since 1980 has been about 20,000 tons per year. Eolian sediment loading to Moses Lake was about 50,000 tons per year before irrigation and land-use development largely stabilized the Moses Lake dune field. Currently, eolian input to the lake is less than 2,000 tons per year. Considering all sediment sources to the lake, most (from 80 to 90 percent) of post-1980 lakebed-sediment accumulation is from autochthonous, or locally formed, mineral matter, including diatom frustuals and carbonate shells, derived from biogenic production in phytoplankton and zooplankton. Suspended-sediment samples collected from Crab Creek and similar nearby waterways in 2007 and 2008 combined with other USGS data from the region indicated that a proposed Bureau of Reclamation supplemental feed of as much as 650 cubic feet per second through Crab Creek might initially contain a sediment load of as much as 1,500 tons per day. With time, however, this sediment load would decrease to about 10 tons per day in the sediment-supply-limited creek as available sediment in the channel is depleted. Sediment loads in the supplemental feed ultimately would be similar to loads in other bypass canals near Moses Lake. Considering the hydrology and geomorphology of the creek over multiple years, there is little evidence that the proposed supplemental feed would substantially increase the overall sediment load from Crab Creek to Moses Lake relative to natural, background conditions. Because Moses Lake is relatively shallow and subject to significant wind-driven circulation currents, mixing also would redistribute some of the fluvial sediment load deposited from Crab Creek throughout Parker Horn and the rest of Moses Lake, further mitigating the local effect of Crab Creek sedimentation near the City of Moses Lake.

Magirl, Christopher S.; Cox, Stephen E.; Mastin, Mark C.; Huffman, Raegan L.

2010-01-01

189

Sedimentation and associated trace metal enrichment in the riparian zone of the Three Gorges Reservoir, China.  

PubMed

Impoundment of the Three Gorges Reservoir has created an artificial riparian zone with a vertical height of 30 m and a total area of 349 km(2), which has been subjected to seasonal inundation and exposure due to regular reservoir impoundment and the occurrence of natural floods. The significant alteration of hydrologic regime has caused numerous environmental changes. The present study investigated the magnitude and spatial pattern of sedimentation and metal enrichment in a typical section of the riparian zone, composed of bench terraces with previous agricultural land uses, and explored their links to the changed hydrologic regime. In particular, we measured the total sediment depths and collected surface riparian sediments and down-profile sectioned riparian soils (at 5 cm intervals) for trace metal determination. Our analysis showed that the annual average sedimentation rates varied from 0.5 to 10 cm·yr(-1) and they decreased significantly with increasing elevation. This lateral distribution was principally attributed to seasonal variations in water levels and suspended sediment concentrations. Enriched concentrations of trace metals were found both in the riparian sediments and soils, but they were generally higher in the riparian sediments than in riparian soils and followed a similar lateral decreasing trend. Metal contamination assessment showed that the riparian sediments were slightly contaminated by Ni, Zn, and Pb, moderately contaminated by Cu, and moderately to strongly contaminated by Cd; while riparian soils were slightly contaminated by As, and moderately contaminated by Cd. Trace metal enrichment in the riparian sediments may be attributed to external input of contaminated sediments produced from upstream anthropogenic sources and chemical adsorption from dissolved fractions during pure sediment mobilization and after sink for a prolonged flooding period due to reservoir impoundment. PMID:24561931

Tang, Qiang; Bao, Yuhai; He, Xiubin; Zhou, Huaidong; Cao, Zhijing; Gao, Peng; Zhong, Ronghua; Hu, Yunhua; Zhang, Xinbao

2014-05-01

190

Changes in bottom-surface elevations in three reservoirs on the lower Susquehanna River, Pennsylvania and Maryland, following the January 1996 flood; implications for nutrient and sediment loads to Chesapeake Bay  

USGS Publications Warehouse

The Susquehanna River drains about 27,510 square miles in New York, Pennsylvania, and Maryland, contributes nearly 50 percent of the freshwater discharge to the Chesapeake Bay, and contributes nearly 66 percent of the annual nitrogen load, 40 percent of the phosphorus load, and 25 percent of the suspended-sediment load from non-tidal parts of the Bay during a year of average streamflow. A reservoir system formed by three hydroelectric dams on the lower Susquehanna River is currently trapping a major part of the phosphorus and suspended-sediment loads from the basin and, to a lesser extent, the nitrogen loads. In the summer of 1996, the U. S. Geological Survey collected bathymetric data along 64 cross sections and 40 bottom-sediment samples along 14 selected cross sections in the lower Susquehanna River reservoir system to determine the remaining sediment-storage capacity, refine the current estimate of when the system may reach sediment-storage capacity, document changes in the reservoir system after the January 1996 flood, and determine the remaining nutrient mass in Conowingo Reservoir. Results from the 1996 survey indicate an estimated total of 14,800,000 tons of sediment were scoured from the reservoir system from 1993 (date of previous bathymetric survey) through 1996. This includes the net sediment change of 4,700,000 tons based on volume change in the reservoir system computed from the 1993 and 1996 surveys, the 6,900,000 tons of sediment deposited from 1993 through 1996, and the 3,200,000 tons of sediment transported into the reservoir system during the January 1996 flood. The January 1996 flood, which exceeded a 100-year recurrence interval, scoured about the same amount of sediment that normally would be deposited in the reservoir system during a 4- to 6-year period. Concentrations of total nitrogen in bottom sediments in the Conowingo Reservoir ranged from 1,500 to 6,900 mg/kg (milligrams per kilogram); 75 percent of the concentrations were between 3,000 and 5,000 mg/kg. About 96 percent of the concentrations of total nitrogen consisted of organic nitrogen. Concentrations of total phosphorus in bottom sediments ranged from 286 to 1,390 mg/kg. About 84 percent of the concentrations of total phosphorus were comprised of inorganic phosphorus. The ratio of concentrations of plant-available phosphorus to concentrations of total phosphorus ranged from 0.6 to 3.5 percent; ratios generally decreased in a downstream direction. About 29,000 acre-feet, or 42,000,000 tons, of sediment can be deposited before Conowingo Reservoir reaches sediment-storage capacity. Assuming the average annual sediment-deposition rate remains unchanged and no scour occurs due to floods, the reservoir system could reach sediment-storage capacity in about 17 years. The reservoir system currently is trapping about 2 percent of the nitrogen, 45 percent of the phosphorus, and 70 percent of the suspended sediment transported by the river to the upper Chesapeake Bay. Once the reservoir reaches sediment-storage capacity, an estimated 250-percent increase in the current annual loads of suspended sediment, a 2-percent increase in the current annual loads of total nitrogen, and a 70-percent increase in the current annual loads of total phosphorus from the Susquehanna River to Chesapeake Bay can be expected. If the goal of a 40-percent reduction in controllable phosphorus load from the Susquehanna River Basin is met before the reservoirs reach sediment-storage capacity, the 40-percent reduction goal will probably be exceeded when the reservoir system reaches sediment-storage capacity.

Langland, Michael J.; Hainly, Robert A.

1997-01-01

191

ANNUAL PROGRESS REPORT. COLLOID GENESIS/TRANSPORT AND FLOW PATHWAY ALTERATIONS RESULTING FROM INTERACTIONS OF REACTIVE WASTE SOLUTIONS AND HANFORD VADOSE ZONE SEDIMENTS  

EPA Science Inventory

The overall objective of this research is to improve our understanding on the effects of interactions between the tank waste solution and sediments on deep contaminant migration under Hanford Site conditions. This objective will be achieved through the following four tasks: (1) c...

192

ANNUAL REPORT. FIXATION MECHANISMS AND DESORPTION RATES OF SORBED CS IN HIGH-LEVEL WASTE CONTAMINATED SUBSURFACE SEDIMENTS: IMPLICATIONS TO FUTURE BEHAVIOR AND IN-GROUND STABILITY  

EPA Science Inventory

Research is investigating mineralogic and geochemical factors controlling the desorption rate of 137Cs+ from subsurface sediments on the Hanford Site contaminated with different types of high-level waste. The project will develop kinetic data and models that describe the release ...

193

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

SciTech Connect

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

S.G.McLin; D.W. Lyons

2002-05-05

194

Suspended-sediment rating curve response to urbanization and wildfire, Santa Ana River, California  

USGS Publications Warehouse

River suspended-sediment concentrations provide insights to the erosion and transport of materials from a landscape, and changes in concentrations with time may result from landscape processes or human disturbance. Here we show that suspended-sediment concentrations in the Santa Ana River, California, decreased 20-fold with respect to discharge during a 34-year period (1968?2001). These decreases cannot be attributed to changes in sampling technique or timing, nor to event or seasonal hysteresis. Annual peak and total discharge, however, reveal sixfold increases over the 34-year record, which largely explain the decreases in sediment concentration by a nonlinear dilution process. The hydrological changes were related to the widespread urbanization of the watershed, which resulted in increases in storm water discharge without detectable alteration of sediment discharge, thus reducing suspended-sediment concentrations. Periodic upland wildfire significantly increased water discharge, sediment discharge, and suspended-sediment concentrations and thus further altered the rating curve with time. Our results suggest that previous inventories of southern California sediment flux, which assume time-constant rating curves and extend these curves beyond the sampling history, may have substantially overestimated loads during the most recent decades.

Warrick, J.A.; Rubin, D.M.

2007-01-01

195

Full implementation of a distributed hydrological model based on check dam trapped sediment volumes  

NASA Astrophysics Data System (ADS)

Lack of hydrometeorological data is one of the most compelling limitations to the implementation of distributed environmental models. Mediterranean catchments, in particular, are characterised by high spatial variability of meteorological phenomena and soil characteristics, which may prevents from transferring model calibrations from a fully gauged catchment to a totally o partially ungauged one. For this reason, new sources of data are required in order to extend the use of distributed models to non-monitored or low-monitored areas. An important source of information regarding the hydrological and sediment cycle is represented by sediment deposits accumulated at the bottom of reservoirs. Since the 60s, reservoir sedimentation volumes were used as proxy data for the estimation of inter-annual total sediment yield rates, or, in more recent years, as a reference measure of the sediment transport for sediment model calibration and validation. Nevertheless, the possibility of using such data for constraining the calibration of a hydrological model has not been exhaustively investigated so far. In this study, the use of nine check dam reservoir sedimentation volumes for hydrological and sedimentological model calibration and spatio-temporal validation was examined. Check dams are common structures in Mediterranean areas, and are a potential source of spatially distributed information regarding both hydrological and sediment cycle. In this case-study, the TETIS hydrological and sediment model was implemented in a medium-size Mediterranean catchment (Rambla del Poyo, Spain) by taking advantage of sediment deposits accumulated behind the check dams located in the catchment headwaters. Reservoir trap efficiency was taken into account by coupling the TETIS model with a pond trap efficiency model. The model was calibrated by adjusting some of its parameters in order to reproduce the total sediment volume accumulated behind a check dam. Then, the model was spatially validated by obtaining the simulated sedimentation volume at the other eight check dams and comparing it to the observed sedimentation volumes. Lastly, the simulated water discharge at the catchment outlet was compared with observed water discharge records in order to check the hydrological sub-model behaviour. Model results provided highly valuable information concerning the spatial distribution of soil erosion and sediment transport. Spatial validation of the sediment sub-model provided very good results at seven check dams out of nine. This study shows that check dams can be a useful tool also for constraining hydrological model calibration, as model results agree with water discharge observations. In fact, the hydrological model validation at a downstream water flow gauge obtained a Nash-Sutcliffe efficiency of 0.8. This technique is applicable to all catchments with presence of check dams, and only requires rainfall and temperature data and soil characteristics maps.

Bussi, Gianbattista; Francés, Félix

2014-05-01

196

Sediment accumulation and net storage determined by field observation and numerical modelling for an extensive tropical floodplain: Beni River, Bolivian Llanos  

NASA Astrophysics Data System (ADS)

Lowland floodplains in subsiding basins form major depocentres responsible for the storage and cycling of large quantities of fine sediment and associated nutrients and contaminants. Obtaining reliable estimates of sediment storage in such environments is problematic due to the high degree of spatial and temporal variability exhibited by overbank sediment accumulation rates, combined with the logistical difficulties inherent in sampling locations far away from the channel. Further complexity is added by the high channel mobility, which recycles sediment and reconfigures the relationships between channel and floodplain morphology, sediment transport and overbank sedimentation. Estimates of floodplain accretion can be derived using a range of numerical sedimentation models of varying complexity. However, data required for model calibration are rarely available for the vast floodplains associated with tropical rivers. We present results from a study of channel-floodplain sediment exchange fluxes on the Rio Beni, a highly dynamic, tropical sand-bed tributary of the Amazon in northern Bolivia. The Beni transports high concentrations of suspended sediment, generated in the river's Andean headwaters, and disperses this material across an extensive floodplain wetland that experiences annual inundation over an area of up to 40000 km2. We utilise estimates of overbank sedimentation rates over the past century derived from 210Pb analysis of floodplain sediment cores collected along a 375 km length of channel, including sampling a range of channel-floodplain configurations within the channel belt and on the distal floodplain (up to 60 km from the channel). These data are used to investigate spatial and temporal variations in rates of floodplain sediment accumulation for a range of grain sizes. Specifically, we examine relationships between sedimentation rate and distance from the channel, and characterise within channel belt variability in sedimentation linked to patterns of channel migration and associated levee reworking. Field data are used to inform a hydrodynamically-driven model of overbank sedimentation and to derive uncertainty-bounded estimates of total floodplain sediment accumulation. Sediment exchange due to planform channel mobility is quantified using a numerical model of meander migration, calibrated using analysis of remote sensing imagery to determine rates and geometry of channel migration. Our combined data and model analysis allows the construction of a mean annual sediment budget for the Beni, which suggests channel-sediment exchange fluxes in the order of 100 Mt a-1, equivalent to 10% of the sediment load of the mainstem Amazon.

Schwendel, Arved; Aalto, Rolf; Nicholas, Andrew

2014-05-01

197

Use of fish functional traits to associate in-stream suspended sediment transport metrics with biological impairment.  

PubMed

Loss of ecological integrity due to excessive suspended sediment in rivers and streams is a major cause of water quality impairment in the USA. Current assessment protocols for development of sediment total maximum daily loads (TMDLs) lack a means to link temporally variable sediment transport rates with specific losses of ecological functions as loads increase. In order to accomplish this linkage assessment, a functional traits-based approach was used to correlate site occurrences of 17 fish species traits in three main groups (preferred rearing habitat, trophic feeding guild, and spawning behavior) with suspended sediment transport metrics. The sediment transport metrics included concentrations, durations, and dosages for a range of exceedance frequencies; and mean annual suspended sediment yields (SSY). In addition, this study in the Northwestern Great Plains Ecoregion examined trait relationships with three environmental gradients: channel stability, drainage area, and elevation. Potential stressor responses due to elevated suspended sediment concentration (SSC) levels were correlated with occurrences of five traits: preferred pool habitat; feeding generalists, omnivores, piscivores, and nest-building spawners; and development of ecologically based TMDL targets were demonstrated for specific SSC exceedance frequencies. In addition, reduced site occurrences for preferred pool habitat and nest-building spawners traits were associated with unstable channels and higher SSY. At an ecoregion scale, a functional traits assessment approach provided a means to quantify relations between biological impairment and episodically elevated levels of suspended sediment, supporting efforts to develop ecologically based sediment TMDLs. PMID:20981569

Schwartz, John S; Simon, Andrew; Klimetz, Lauren

2011-08-01

198

Fine-suspended sediment and water budgets for a large, seasonally dry tropical catchment: Burdekin River catchment, Queensland, Australia  

NASA Astrophysics Data System (ADS)

The Burdekin River catchment (˜130,400 km2) is a seasonally dry tropical catchment located in north-east Queensland, Australia. It is the single largest source of suspended sediment to the Great Barrier Reef (GBR). Fine sediments are a threat to ecosystems on the GBR where they contribute to elevated turbidity (reduced light), sedimentation stress, and potential impacts from the associated nutrients. Suspended sediment data collected over a 5 year period were used to construct a catchment-wide sediment source and transport budget. The Bowen River tributary was identified as the major source of end-of-river suspended sediment export, yielding an average of 530 t km-2 yr-1 during the study period. Sediment trapping within a large reservoir (1.86 million ML) and the preferential transport of clays and fine silts downstream of the structure were also examined. The data reveal that the highest clay and fine silt loads—which are of most interest to environmental managers of the GBR—are not always sourced from areas that yield the largest total suspended sediment load (i.e., all size fractions). Our results demonstrate the importance of incorporating particle size into catchment sediment budget studies undertaken to inform management decisions to reduce downstream turbidity and sedimentation. Our data on sediment source, reservoir influence, and subcatchment and catchment yields will improve understandings of sediment dynamics in other tropical catchments, particularly those located in seasonally wet-dry tropical savannah/semiarid climates. The influence of climatic variability (e.g., drought/wetter periods) on annual sediment loads within large seasonally dry tropical catchments is also demonstrated by our data.

Bainbridge, Zoë T.; Lewis, Stephen E.; Smithers, Scott G.; Kuhnert, Petra M.; Henderson, Brent L.; Brodie, Jon E.

2014-11-01

199

Design of a new total knee replacement An estimated 1.3 million artificial knee joints are implanted annually around the world.  

E-print Network

Design of a new total knee replacement An estimated 1.3 million artificial knee joints of the world's leading manufacturers of total knee replacements to support them in developing new and better joints are well-designed, robust and long lasting. Millions of artificial knee joints have now been

Sóbester, András

200

MODELING FRAMEWORK FOR EVALUATING SEDIMENTATION IN STREAM NETWORKS: FOR USE IN SEDIMENT TMDL ANALYSIS  

EPA Science Inventory

A modeling framework that can be used to evaluate sedimentation in stream networks is described. This methodology can be used to determine sediment Total Maximum Daily Loads (TMDLs) in sediment impaired waters, and provide the necessary hydrodynamic and sediment-related data t...

201

The efficacy of oxidative coupling for promoting in-situ immobilization of hydroxylated aromatics in contaminated soil and sediment systems. 1998 annual progress report  

SciTech Connect

'Hydroxylated aromatic compounds (HAC''s) and their precursors are common contaminants of surface and subsurface systems at DOE facilities. The environmental fate and transport of such compounds, particularly in subsurface systems, is generally dominated by their sorption and desorption by soils and sediments. Certain secondary chemical reactions, most specifically abiotic and/or enzymatic oxidative coupling, may be significant in controlling the sorption and subsequent desorption of such hydroxylated aromatics by soils and sediments. The principal objectives of this study are to investigate: (1) the role of abiotic/enzymatic coupling reactions on the immobilization of HAC''s; (2) the effects of environmental factors on such immobilization; and (3) preliminary engineering approaches utilizing enhanced abiotic/enzymatic coupling reactions to immobilize hydroxylated aromatics in-situ. Information gathered from the study will be useful in quantifying the behavior of this class of organic compounds in various subsurface contamination scenarios relevant to DOE facilities, and in specifying strategies for the selection and design of remediation technologies. Over the first two years of this three-year project, the authors have developed a significantly improved understanding of the mechanisms of hydroxylated aromatic compound sorption and immobilization by natural soils and sediments. Immobilization in this context is attributed to oxidative coupling of the hydroxylated aromatics subsequent to their sorption to a soil or sediment, and is quantified in terms of the amount of a sorbed target compound retained by a sorbent after a series of sequential water and solvent extractions. The presence of oxygen, metal oxides, and organic matter, all of which can potentially catalyze/facilitate the abiotic oxidative coupling of HAC''s, were investigated during these first two years. Three different HAC''s: phenol, trichlorophenol and o-cresol were included in the experimental program. Inorganic soil matrices were represented by a glacial wash sand (Wurtsmith sand) having very low organic content. Because the chemical nature of soil organic matter may potentially affect the extent of coupling or immobilization, sorbents having different organic matter compositions are being investigated. Two of the three studied to date are near-surface soils, characterized by geologically younger organic material (Fox Forest soil and Fox Grassland soil). The third sorbent is an older and diagenetically altered soil (Lachine Shale). Sorbent preparation, characterization and experimental protocol development were completed in the first year of the study while the second year of the project has focused primarily on experiments with natural systems, as planned. Preliminary work with engineered systems has been initiated earlier than scheduled in order to integrate and relate all aspects of the study.'

Weber, W.J. [Univ. of Michigan, Ann Arbor, MI (US); Bhandari, A. [Kansas State Univ., Manhattan, KS (US)

1998-06-01

202

Effects of land use and retention practices on sediment yields in the Stony Brook basin, New Jersey  

USGS Publications Warehouse

The average annual rate of suspended-sediment discharge of the Stony Brook at Princeton, N.J. (44.5 square miles) is about 8,800 tons, or 200 tons per square mile. Annual yields within the basin, which is in the Piedmont Lowlands section of the Piedmont physiographic province in west-central New Jersey, range from 25 to 400 tons per square mile. Storm runoff that transports suspended materials in excess of a ton carries 90 percent of the total suspended-sediment discharge from the basin. Observations of particlesize distributions indicate that the suspended material carried during storms is 55 percent silt, 40 percent clay, and 5 percent sand. A trend analysis of sediment records collected at Princeton between 1956 and 1970 indicated an increase in suspended-sediment discharge per unit of water discharge during 1956-61. From early 1962 to late 1967, sediment trends were difficult to interpret owing to complicating factors, such as reservoir construction, urbanization, and extreme drought. After 1967, yields decreased. Variations in sediment yields during the study are attributed to the integrated influence of several factors. A 2.9 percent decrease in croplands and an increase of 5.1 percent in idle and urban land use probably produced a net increase in sediment yields. Construction of seven sediment-retention reservoirs under Public Law 566 resulted in temporary increases in sediment yields. However, based on a trap-efficiency investigation at 1 site, the combined effect of operation of these 7 reservoirs is estimated to result in a 20 percent reduction in sediment discharge from the basin. Other factors that influence the noted decrease include reduction in yields during 5 years of drought, 1962-66, and reduced construction and development during the latter part of the study period resulting from a general economic slowdown.

Mansue, Lawrence J.; Anderson, Peter W.

1974-01-01

203

Aquatic Sediments.  

ERIC Educational Resources Information Center

Presents a literature review of aquatic sediments and its effect upon water quality, covering publications of 1976-77. This review includes: (1) sediment water interchange; (2) chemical and physical characterization; and (3) heavy water in sediments. A list of 129 references is also presented. (HM)

Sanville, W. D.; And Others

1978-01-01

204

AQUATIC SEDIMENTS  

EPA Science Inventory

One hundred seventeen literature references in the area of freshwater sediments were abstracted and synthesized to produce a review of sediment-related research for the period November, 1975 through October, 1976. Research areas covered included sediment-water interchange, sampli...

205

Effects of urbanization on streamflow and sediment transport in the Rock Creek and Anacostia River basins, Montgomery County, Maryland, 1962-74  

USGS Publications Warehouse

Land use, precipitation, streamflow, and sediment discharge data were collected from nine small drainage basins in Montgomery County, Maryland, to evaluate runoff and sediment response to sediment-control practices in areas undergoing urban development. Drainage basins ranged in size from 0.35 to 21.1 sq mi and land use ranged from rural to 60 percent urban. Urbanization did not affect low and medium flows, but it did result in increased storm runoff and peak flows. Suspended sediment transported from one of the basins that underwent urban development, the 21.1 sq mi Anacostia River basin, averaged 15 ,400 tons/yr between 1962 and 1974. Bedload was estimated as 5 to 11 percent of the total load. Cropland, urban land, and construction sites were the major sources of sediment. Average annual sediment yields ranged from 065 to 4.3 tons/acre for cropland, 3.7 tons/acre for urban land, and 7 to 100 tons/acre for urban construction sites. The magnitude of the yields from construction sites was significantly affected by (1) the slope of the sites, (2) the proximity of stream channels, (3) buffer zones of natural vegetation, and (4) sediment-control measures. Sediment controls, particularly those enforced under a 1971 sediment-control ordinance, apparently decreased construction-site sediment yields by 60 to 80 percent. (Woodard-USGS)

Yorke, Thomas H.; Herb, William J.

1978-01-01

206

Multivariate Models of Watershed Suspended Sediment Loads for the Eastern United States  

Microsoft Academic Search

Estimates of mean annual watershed sediment load, derived from suspended sediment concentration and streamflow data, are often not available at locations of interest. The purpose of this study was to develop multivariate regression models of mean annual suspended sediment loads useful for most river locations in the eastern United States. The resulting models may be used at ungaged river locations

David C. Roman; Richard M. Vogel; Gregory E. Schwarz

207

A sediment budget for the southern reach in San Francisco Bay, CA: implications for habitat restoration  

USGS Publications Warehouse

The South Bay Salt Pond Restoration Project is overseeing the restoration of about 6000 ha of former commercial salt-evaporation ponds to tidal marsh and managed wetlands in the southern reach of San Francisco Bay (SFB). As a result of regional groundwater overdrafts prior to the 1970s, parts of the project area have subsided below sea-level and will require between 29 and 45 million m3 of sediment to raise the surface of the subsided areas to elevations appropriate for tidal marsh colonization and development. Therefore, a sufficient sediment supply to the far south SFB subembayment is a critical variable for achieving restoration goals. Although both major tributaries to far south SFB have been seasonally gaged for sediment since 2004, the sediment flux at the Dumbarton Narrows, the bayward boundary of far south SFB, has not been quantified until recently. Using daily suspended-sediment flux data from the gages on Guadalupe River and Coyote Creek, combined with continuous suspended-sediment flux data at Dumbarton Narrows, we computed a sediment budget for far south SFB during Water Years 2009–2011. A Monte Carlo approach was used to quantify the uncertainty of the flux estimates. The sediment flux past Dumbarton Narrows from the north dominates the input to the subembayment. However, environmental conditions in the spring can dramatically influence the direction of springtime flux, which appears to be a dominant influence on the net annual flux. It is estimated that up to several millennia may be required for natural tributary sediments to fill the accommodation space of the subsided former salt ponds, whereas supply from the rest of the bay could fill the space in several centuries. Uncertainty in the measurement of sediment flux is large, in part because small suspended-sediment concentration differences between flood and ebb tides can lead to large differences in total mass exchange. Using Monte Carlo simulations to estimate the random error associated with this uncertainty provides a more statistically rigorous method of quantifying this uncertainty than the more typical “sum of errors” approach. The results of this study reinforce the need for measurement of estuarine sediment fluxes over multiple years (multiple hydrologic conditions) to adequately detail the variability in flux. Additionally, the timing of breaching events for the restoration project could be tied to annual hydrologic conditions to capitalize on increased regional sediment supply.

Shellenbarger, Gregory G.; Wright, Scott A.; Schoellhamer, David H.

2013-01-01

208

Simulation of contaminated sediment transport in White Oak Creek basin  

SciTech Connect

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 ({sup 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 {sup 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.

Bao, Y.; Clapp, R.B.; Brenkert, A.L. [Oak Ridge National Lab., TN (United States); Moore, T.D. [Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN (United States); Fontaine, T.A. [Department of Civil and Environmental Engineering, South Dakota School of Mines and Technology, Rapid City, SD (United States)

1995-12-31

209

Channel Incision and Suspended Sediment Delivery at Caspar Creek, Mendocino County, California.  

NASA Astrophysics Data System (ADS)

Tributary and headwater valleys in the Caspar Creek watershed, in coastal Mendocino County, California, show signs of incision along much of their lengths. An episode of incision followed initial-entry logging which took place between 1860 and 1906. Another episode of incision cut into skid-trails created for second-entry logging in the 1970's. Gullies resulting from both of these episodes of incision are sensitive to hydrologic fluctuations and feature active headcuts, deepening plungepools, and unstable banks, which continue to contribute sediment to the Caspar Creek channel network. Headcuts are numerous in each channel. In some cases headcuts define the upstream extent of an incised reach; in many cases headcuts migrate up previously incised reaches, increasing the depth of incision. Surveys indicate that bank retreat, plunge pool deepening, and headcut retreat all contributed sediment to the channels between 2000 and 2003. Since bank walls have considerably more surface area than headwalls per given length of channel, and headcuts have largely migrated into positions temporarily constrained by resistant lips, bankwall retreat appears to be a more significant chronic source of sediment than headwall retreat. Stream gage records show that some channels consistently deliver higher levels of suspended sediment than others. In comparing channels, ongoing levels of suspended sediment delivery correlate well with total amount of exposed channel bank (depth of incision integrated over length of channel) in the reaches upstream of stream gages. On an annual to decadal time-scale, rates of suspended sediment delivery per unit area of catchment correlate better with the amount of exposed bank area in reaches upstream of stream gages, than with the volume of sediment delivered by landslide events, with total catchment area, or with peak storm flow per unit area. The correlation between amount of exposed bank area and ongoing levels of suspended sediment delivery is attributable to the importance of bank erosion as a sediment source to these gullied channels.

Dewey, N. J.; Lisle, T. E.; Reid, L. M.

2003-12-01

210

Annual report of 1991 groundwater monitoring data for the Kerr Hollow Quarry and Chestnut Ridge Sediment Disposal Basin at the Y-12 Plant: Ground water surface elevations  

SciTech Connect

The purpose of this document is to provide a summary and interpretation of hydraulic head measurements obtained from wells surrounding the Kerr Hollow Quarry and Chestnut Ridge Sediment Disposal Basin sites at the US Department of Energy Y-12 Plant in Oak Ridge, Tennessee. Periodic water level observations are presented using hydrographs and water table contour maps based on data obtained from quarterly sampling during calendar year 1991. Generalized, preliminary interpretation of results are presented. The two sites covered by this report have interim status under the provisions of the Resource Conservation and Recovery Act (RCRA). A subset of the wells at each rate are used for groundwater monitoring purposes under the requirements of RCRA. A discussion of the up-gradient and down-gradient directions for each of the sites is included.

Shevenell, L. [Tennessee Univ., Knoxville, TN (United States); Switek, J. [Oak Ridge National Lab., TN (United States)

1992-02-01

211

A combined model of sediment production, supply and transport  

NASA Astrophysics Data System (ADS)

In previous sediment-runoff models, the sediment production rates of mountain slopes, and the sediment supply rates to streams typically have been developed using empirical methods. A process-based model for sediment production and supply is, however, required for more exact simulations of sediment runoff. In this study, we develop a method to calculate the sediment production rate due to both freeze-thaw action and the sediment supply rate (i.e. erosion rate of talus). These numerical models were then connected to an existing sediment transport model. The integrated model presented here was applied to a small mountainous watershed. We found that the calculated sediment production rate was within the range of values typically observed for this region. Additionally, the estimated annual sediment discharge using the model agreed with observational results. Lastly, we found that the model can be used to qualitatively characterize typical features of the actual sediment routine in mountainous watersheds.

Fujita, M.; Yamanoi, K.; Izumiyama, H.

2015-03-01

212

Assessment of soil erosion and sediment yield in Liao watershed, Jiangxi Province, China, Using USLE, GIS, and RS  

Microsoft Academic Search

Soil erosion by water is a serious problem all over the world. In China, about 1 790 000 km2 of land suffers from water erosion, which accounts for 18.3% of China’s total area. This study was conducted in the Liao\\u000a (?) watershed in Jiangxi (??) Province to assess annual soil erosion and sediment yield using the Universal Soil Loss Equation

Li Hui; Chen Xiaoling; Kyoung Jae Lim; Cai Xiaobin; Myung Sagong

2010-01-01

213

Estimating suspended sediment and trace element fluxes in large river basins: Methodological considerations as applied to the NASQAN programme  

USGS Publications Warehouse

In 1994, the NASQAN (National Stream Quality Accounting Network) programme was redesigned as a flux-based water-quality monitoring network for the Mississippi, Columbia, Colorado, and Rio Grande Basins. As the new programme represented a departure from the original, new sampling, processing, analytical, and data handling procedures had to be selected/developed to provide data on discharge, suspended sediment concentration, and the concentrations of suspended sediment and dissolved trace elements. Annual suspended sediment fluxes were estimated by summing daily instantaneous fluxes based on predicted suspended sediment concentrations derived from discharge-based log-log regression (rating-curve) models. The models were developed using both historical and current site-specific discharge and suspended sediment concentrations. Errors using this approach typically are less than ?? 10% for the 3-year reporting period; however, the magnitude of the errors increases substantially for temporal spans shorter than 1 year. Total, rather than total-recoverable, suspended sediment-associated trace element concentrations were determined by direct analysis of material dewatered from large-volume whole-water samples. Site-specific intra- and inter-annual suspended sediment-associated chemical variations were less (typically by no more than a factor of two) than those for either discharge or suspended sediment concentrations (usually more than 10-fold). The concentrations, hence the annual fluxes, for suspended sediment-associated phosphorus and organic carbon, determined by direct analyses, were higher than those determined using a more traditional paired, whole-water/filtered-water approach (by factors ranging from 1.5- to 10-fold). This may be important for such issues as eutrophication and coastal productivity. Filtered water-associated (dissolved) trace element concentrations were markedly lower than those determined during the historical NASQAN programme; many were below their respective detection limits. This resulted from the use of clean sampling, processing, and analytical protocols. Hence, the fluxes for filtered water-associated (dissolved) Ag, Pb, Co, V, Be, Sb, and Se, as well as the total (filtered water plus suspended sediment-associated) fluxes for these constituents, could not be estimated.

Horowitz, A.J.; Elrick, K.A.; Smith, J.J.

2001-01-01

214

Temporal and spatial variability of sediment flux into the sea from the three largest rivers in China  

NASA Astrophysics Data System (ADS)

The Yellow, Yangtze and Pearl Rivers supply over 90% of the sediment flux from China to the western Pacific Ocean. Trends and abrupt changes in the water discharge and sediment load of the three rivers were examined and compared based on data updated to the year 2011 at the seasonal and annual scales. The total water discharge from the three rivers shows a statistically insignificant decreasing trend with a rate of 0.62 × 109 m3/a, and the total sediment load shows a statistically significant decreasing trend at a rate of 31.12 × 106 t/a from the 1950s to 2011. The water discharge of the entire Yellow River and the upstream portion of the Yangtze River shows significant decreasing trends, and that of the mid-lower stream of Yangtze River and the entire Pearl River shows insignificant trends. The sediment loads in the three river basins all show significant decreasing trends at the annual and seasonal scales, and a dramatic decrease in the 2000s resulted in a more obvious decreasing trend over the studied period. From the 1950s to the 2000s, the contribution of sediment flux from the Yellow River to the ocean decreased from 71.8% to 37.0%, and the contributions of the Yangtze and Pearl Rivers increased from 24.2% and 4.0% to 53.0% and 10.0%, respectively. Inter-annual variations in water discharge and sediment load were affected by climate oscillations, such as the El Niño/Southern Oscillation, and the long-term decreasing trend in sediment load was primarily caused by human activities. Dam constructions and soil conservation projects were the major causes of sediment reduction. From the 1970s to the 2000s, the decrease in total sediment load from the three rivers caused by climate change and human activities was 2.24 × 108 t/a (23.0%) and 7.5 × 108 t/a (77.0%), respectively. In the coming decades, the sediment flux from the three rivers into the sea will decrease further with intensifying human activities, resulting in many challenges for the management of river basins and river deltas.

Liu, Feng; Yang, Qingshu; Chen, Shenliang; Luo, Zhifa; Yuan, Fei; Wang, Runtian

2014-06-01

215

Annual Energy Review, 2008  

SciTech Connect

The Annual Energy Review (AER) is the Energy Information Administration's (EIA) primary report of annual historical energy statistics. For many series, data begin with the year 1949. Included are statistics on total energy production, consumption, trade, and energy prices; overviews of petroleum, natural gas, coal, electricity, nuclear energy, renewable energy, and international energy; financial and environment indicators; and data unit conversions.

None

2009-06-01

216

Mechanisms of flow through compressible porous beds in sedimentation, filtration, centrifugation, deliquoring, and ceramic processing. [Annual report], February 1, 1991--January 31, 1992  

SciTech Connect

The University of Houston research program is aimed at the specific area of solid/liquid separation including sedimentation, thickening, cake filtration, centrifugation, expression, washing, deep-bed filtration, screening, and membrane separation. Unification of the theoretical approaches to the various solid/liquid separation operations is the principle objective of the research. Exploring new aspects of basic separation mechanisms, verification of theory with experiment, development of laboratory procedures for obtaining data for design, optimizing operational methods, and transferring the results to industry are a part of the Houston program. New methodology developed in our program now permits an engineer or scientist to handle thickening, cake filtration, centrigual filtration, and expression in a unified manner. The same fundamental equations are simply adapted to the differing parameters and conditions related to the various modes of separation. As the system is flexible and adaptable to computational software, new developments can continually be added. Discussions of the various research projects in this report have been kept to a minimum and are principally qualitative. The length of the report would be excessive if each topic were covered in depth. Although the number of research topics may appear larger than one would expect, many are closely interconnected and reflect our philosophy of working in apparently diverse fields such as ceramics, mining, wastewater, food, chemical processing, and oil well operations.

Tiller, F.M.

1992-06-01

217

Annual report of 1995 groundwater monitoring data for the Kerr Hollow Quarry and Chestnut Ridge Sediment Disposal Basin, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee  

SciTech Connect

The Kerr Hollow Quarry (KHQ) and the Chestnut Ridge Sediment Disposal Basin (CRSDB) are inactive waste management sites located at the Oak Ridge Y-12 Plant. The KHQ and CRSDB are regulated as treatment, storage, or disposal (TSD) facilities under the Resource Conservation and Recovery Act (RCRA). The facilities were granted interim status in calendar year (CY) 1986 under Tennessee Department of Environment and Conservation (TDEC) Hazardous Waste Management Rule 1200-1-11-.05. Historical environmental monitoring data and baseline characterization under interim status indicated that releases of contaminants to groundwater had not occurred; thus, the detection monitoring was implemented at the sites until either clean closure was completed or post-closure permits were issued. The CRSDB was closed in Cy 1989 under a TDEC-approved RCRA closure plan. A revised RCRA PCPA for the CRSDB was submitted by DOE personnel to TDEC staff in September 1994. A final post-closure permit was issued by the TDEC on September 18, 1995. Closure activities at KHQ under RCRA were completed in October 1993. The Record of Decision will also incorporate requirements of the RCRA post-closure permit once it is issued by the TDEC.

NONE

1996-02-01

218

Assessment of hydrology, suspended sediment and particulate organic carbon transport in a large agricultural catchment using SWAT model  

NASA Astrophysics Data System (ADS)

Suspended sediment transport from agricultural catchments to stream networks is responsible for aquatic habitat degradation, reservoir sedimentation and the transport of sediment-bound pollutants (pesticides, particulate nutrients, heavy metals and other toxic substances). Quantifying and understanding the dynamics of suspended sediment transfer from agricultural land to watercourses is essential in controlling soil erosion and in implementing appropriate mitigation practices to reduce stream suspended sediment and associated pollutant loads, and hence improve surface water quality downstream. Gascogne area, southwest France, has been dominated by anthropogenic activities particularly intensive agriculture causing severe erosion in recent decades. This leads to a major threat to surface water quality due to soil erosion. Therefore, the catchment water quality has been continuously monitored since January 2007 and the historical data of hydrology and suspended sediment has existed since 1998. In this study, the Soil and Water Assessment Tool (SWAT 2005) was applied to assess hydrology, suspended sediment and particulate organic carbon in this catchment Agricultural management practices (crop rotation, planting date, fertilizer quantity and irrigations) were taken into the model for simulation period of 11 years (July, 1998 to March, 2009). The investigation was conducted using a 11-year streamflow and two years of suspended sediment record from January 2007 to March 2009. Modelling strategy with dominant landuse and soil type was chosen in this study. The SWAT generally performs satisfactorily and could simulate both daily and monthly runoff and sediment yield. The simulated daily and monthly runoff matched the observed values satisfactorily (ENash>0.5). For suspended sediment simulation, the simulated values were compared with the observed continuous suspended sediment derived from turbidity data. Based on the relationship between SSC and POC (R2 = 0.93), POC was modelled by simulated SSC from SWAT. The model predicted that the average annual catchment rainfall of the 11-year evaluation period (726 mm) with evapotranspiration (78.3%), percolation/groundwater recharge (14.1%), transmission loss (0.5%), and yielding surface runoff (7.1%). The simulated average total water yield of 11 years accounted for 138 mm (observed=133mm) and annual sediment yield varying from 4766 t to 123000 t (Mean= 48 t km-2). The annual yield of particulate organic carbon ranged from 120 t to 3100 t (Mean=1.2 t km-2).

Chantha, Oeurng; Sabine, Sauvage; José-Miguel, Sánchez-Pérez

2010-05-01

219

Measuring and Modeling the Effects of Development on Sediment Production and Delivery, St. John, U.S. Virgin Islands  

NASA Astrophysics Data System (ADS)

Increases in sediment delivery rates into tropical marine environments may pose a serious threat to nearshore coral reef communities. The island of St. John in the U.S. Virgin Islands is at particular risk because the areas outside of the Virgin Islands National Park are being subjected to rapid development, 80% of its land surface has slopes greater than 30%, and the average annual erosivity is 13,500 MJ mm ha-1 hr-1. The objectives of this study were to: (1) measure erosion rates from a variety of anthropogenic and natural sources; and (2) develop a GIS-based model to estimate basin-scale increases in sediment delivery. Sediment production rates were measured from unsurfaced roads, road cutslopes, undisturbed hillslopes, streambanks, and treethrow. Unsurfaced roads had the highest erosion rates with values of up to 38 kg m-2 yr-1, while road cutslopes generated only about 0.8 kg m-2 yr-1. Since undisturbed areas generated only 0.001 kg m-2 yr-1, unsurfaced roads can increase hillslope-scale sediment production rates by up to four orders of magnitude. Sediment production rates from erodible streambanks were estimated to be nearly 13 kg m-2 yr-1, while uprooting of trees along stream margins was estimated to deliver 0.17 kg yr-1 of sediment per meter of stream length. The St. John Erosion model (STJ-EROS) uses a series of empirical sediment production models and sediment delivery ratios to estimate watershed-scale sediment yields in a GIS-based system. Using this model, the estimated sediment yields for the highly-developed 6.0 km2 Fish Bay basin was 41 tons km-2 yr-1, while the estimated sediment yield for the less-developed 4.3 km2 Lameshur Bay basin was only 11 tons km-2 yr-1. The model simulations suggest that current sediment yields are seven and four times above undisturbed conditions in the Fish Bay and Lameshur Bay basins, respectively. The predicted sediment yields are consistent with measured sediment yields and sedimentation rates in both Fish Bay and Lameshur Bay. In both cases actively used unsurfaced roads were identified as the dominant source of sediment. Cutslopes and streambanks played a secondary role in total sediment yields, while undisturbed hillslopes and treethrow contributed only minimal amounts.

Ramos-Scharron, C. E.; MacDonald, L. H.

2003-12-01

220

Effective discharge for suspended sediment transport of the Ganga River and its geomorphic implication  

NASA Astrophysics Data System (ADS)

Effective discharge (Qe) for suspended sediment transport in the alluvial reaches of the Ganga River in the western Ganga plains (WGP) has been computed using ‘analytical' and an alternative ‘magnitude-frequency' approach. Thirty years of mean monthly discharge data from various sites of the Ganga River have been assessed, and the abundance of discharge occurrence has been determined. Our analysis shows that less than 40% of the flow causes effective sediment transport in the Ganga, and this can be considered as the effective discharge for suspended sediment transport. Alternatively, 50% of the sediment load for all studied sites is moved by a discharge varying between 14 and 40% of the total discharge. Effective discharges calculated over the period of record are well below the bankfull discharges (Qb). A few events are close to the bankfull level, but with a high return period (RI > 40 years), and therefore, not effective to transport most of the available sediments. Our computation shows that the mean annual discharge (RI = 2.33 yrs) can transport only 0 to 10% of the total available sediments. The computation of effective discharge also provided important insights to understand the linkage between hydrology and channel morphology. Sediment storage and removal processes, which are reflected in sediment budget, cause changes in cross-sectional area/channel bathymetry at various sites but the channel margins are not affected. A high ratio of bankfull to effective discharge (Qb/Qe) forces the flow lines to be concentrated to the thalweg position and channels are incised. Our study also implies that incision and aggradation of the river valley during a relatively long period are caused by changes in effective discharge. We argue that the valley incision and filling episodes in the western Ganga plains at Late Quaternary timescales in response to monsoonal fluctuations were primarily affected by changes in the effective discharges of the rivers.

Roy, N. G.; Sinha, R.

2014-12-01

221

A graphical method to study suspended sediment dynamics during flood events in the Wadi Sebdou, NW Algeria (1973-2004)  

NASA Astrophysics Data System (ADS)

Small sub-basins are numerous in Mediterranean area and global sedimentary budgets cannot be obtained without a detailed understanding of the hydroclimatic processes that govern sediment fluxes in these small river systems. In this study, the shape of the relationship between sediment concentration (C) and water discharge (Q) during flood events of a 31-years period (1973-2004) was analyzed at the outlet of the Wadi Sebdou basin (256 km2) in northwest Algeria, using a new graphical analysis method based on features of hysteresis loops. Each flood was decomposed as successive stages - each of which being characterized by a sediment rating curve - and used to quantify the contribution of diverse sediment sources within the basin. Seven common classes of hydrological events (single valued and six hysteresis loops: clockwise, counter-clockwise, eight-shaped, single valued plus one loop, either clockwise or counter-clockwise, and single valued plus at least two loops) were explored. Sediment supply from locally derived sources (or "base load") was high and reached 77% of total sediment yield for the study period, and was attributed to weathering of bed material or gullies. The remainder portion was derived from hill-slopes, re-suspension of fresh fine deposits in the river bed, or bank collapse. The ratio of suspended sediment load derived from active sediment source varies considerably from one flood to another depending on many factors, such as seasonality and antecedent type of flood. The simpler floods were the most frequent ones but produced less sediment. The most frequent floods were clockwise or anticlockwise (52% of floods) but brought only 34% of the total sediment flux. The 18% of the most complex floods (single valued plus at least two loops) produced more than 53% of the sediments, mainly supplied by base load (84%). Intra-annual variability was very high. Over 31-years, the five biggest floods cumulated 64% of the total sediment flux and were of three classes, the most complex floods being dominant. The largest contribution occurred during one single 33-days long hydrological event with complex form which represented 26% of the total sediment flux. Apart from the five biggest flood events, the base load represented 53%. The biggest floods favour base load as compared to the smallest ones.

Megnounif, Abdesselam; Terfous, Abdelali; Ouillon, Sylvain

2013-08-01

222

Institute of Water Resources Annual Technical Report  

E-print Network

Pollution, Surface Water, Water Quality Descriptors: Bacteria, Suspended Sediments, Water Quality Monitoring Pollution, Surface Water, WInstitute of Water Resources Annual Technical Report FY 2002 Introduction In fiscal year 2002

223

Water Resources Center Annual Technical Report  

E-print Network

in water resources, including the management of water resources among competing uses; controlling pollution Quality Focus Category: Water Quality, Sediments, Non Point Pollution Descriptors: AgricultureWater Resources Center Annual Technical Report FY 2001 Introduction Research Program Research

224

Aquatic sediments  

SciTech Connect

The authors present a literature review concerning sediment properties, interactions, and conditions. Topics of discussion include the following: biological activity and toxicity; nutrients; metals; organic compounds; dredging; radionuclides; oxygen demand and organic carbon; mathematical modeling; sediment transport and suspension; and paleolimnology.

Bonner, J.S.; Autenrieth, R.L.; Schreiber, L. (Texas A and M Univ., College Station (United States))

1990-06-01

225

ANNUAL REVIEW ANNUAL REVIEW  

E-print Network

RCA ANNUAL REVIEW 2010/11 #12;RCA ANNUAL REVIEW 2010/11 #12;`The objects of the College Neil Cossons Rector and Vice-Provost Dr Paul Thompson #12;4 Rector's Review 6 Student Statistics 2010 Studies Critical Writing in Art & Design Curating Contemporary Art V&A /RCA History of Design 26 School

Subramanian, Sriram

226

Sediment discharge from an area of highway construction, Applemans Run basin, Columbia County, Pennsylvania  

USGS Publications Warehouse

The effects of highway construction on stream sediment loads were studied in Applemans Run basin, Columbia County, Pa., from October 1971 to May 1974. During the investigations, about 5,200 tons of suspended-sediment were discharged from the basin. Of this amount, about 2,700 tons, or about half the total sediment discharge, as derived from the highway construction area. Annual suspended-sediment yields from 17.5 acres under construction ranged from 40,000 to 66,000 tons/sq mi in the 1972 and 1973 water years, respectively. In the 1972 and 1973 er years of active construction, 83 percent of the sediment transported from the construction site was eroded each year in storms from January to June. Seasonal trends in sediment discharge for 1972 show that 69 percent of that year 's suspended-load was transported in April, May, and June, whereas less than 1 percent was transported in July, August, and September. (Woodard-USGS)

Eckhardt, David A.V.

1976-01-01

227

Flux estimates and sedimentation of polychlorinated naphthalenes in the northern part of the Baltic Sea.  

PubMed

The concentrations and fluxes of polychlorinated naphthalenes (PCNs) were measured in surface sediments, and settling particulate matter collected in sediment traps, at two coastal and two offshore sampling stations in the Gulf of Bothnia, northern Baltic Sea, Sweden. The PCN concentrations (of tetra- to hepta-chloro congeners) in the surface sediments ranged from 0.27 to 2.8 ng/g dry weight and were of the same order of magnitude as background concentrations reported previously in Europe. The PCN fluxes in the southern basin (0.93 and 0.86 microg/m2/year) of the Gulf of Bothnia were higher than those in the northern basin (0.58 and 0.49 microg/m2/year); they were also higher near the coast than in the open sea. These PCN fluxes are similar to the pre-industrial levels determined from lake sediments in northwest England. The PCN homologue distribution changed from a relatively even distribution in samples collected near the coast, to TeCNs dominating in the samples from the open sea. This indicates that higher chlorinated PCNs are deposited and retained in sediments to a higher degree near the coast. The total annual deposition of PCNs in sediments in the Gulf of Bothnia was estimated to be 91 kg/year. PMID:12860106

Lundgren, Kjell; Tysklind, Mats; Ishaq, Rasha; Broman, Dag; van Bavel, Bert

2003-01-01

228

Using sediment 'fingerprints' to assess sediment-budget errors, north Halawa Valley, Oahu, Hawaii, 1991-92  

USGS Publications Warehouse

Reliable estimates of sediment-budget errors are important for interpreting sediment-budget results. Sediment-budget errors are commonly considered equal to sediment-budget imbalances, which may underestimate actual sediment-budget errors if they include compensating positive and negative errors. We modified the sediment 'fingerprinting' approach to qualitatively evaluate compensating errors in an annual (1991) fine (<63 ??m) sediment budget for the North Halawa Valley, a mountainous, forested drainage basin on the island of Oahu, Hawaii, during construction of a major highway. We measured concentrations of aeolian quartz and 137Cs in sediment sources and fluvial sediments, and combined concentrations of these aerosols with the sediment budget to construct aerosol budgets. Aerosol concentrations were independent of the sediment budget, hence aerosol budgets were less likely than sediment budgets to include compensating errors. Differences between sediment-budget and aerosol-budget imbalances therefore provide a measure of compensating errors in the sediment budget. The sediment-budget imbalance equalled 25% of the fluvial fine-sediment load. Aerosol-budget imbalances were equal to 19% of the fluvial 137Cs load and 34% of the fluval quartz load. The reasonably close agreement between sediment- and aerosol-budget imbalances indicates that compensating errors in the sediment budget were not large and that the sediment-budget imbalance as a reliable measure of sediment-budget error. We attribute at least one-third of the 1991 fluvial fine-sediment load to highway construction. Continued monitoring indicated that highway construction produced 90% of the fluvial fine-sediment load during 1992. Erosion of channel margins and attrition of coarse particles provided most of the fine sediment produced by natural processes. Hillslope processes contributed relatively minor amounts of sediment.

Hill, B.R.; DeCarlo, E.H.; Fuller, C.C.; Wong, M.F.

1998-01-01

229

Comparison of sediment supply to San Francisco Bay from watersheds draining the Bay Area and the Central Valley of California  

USGS Publications Warehouse

Quantifying suspended sediment loads is important for managing the world's estuaries in the context of navigation, pollutant transport, wetland restoration, and coastal erosion. To address these needs, a comprehensive analysis was completed on sediment supply to San Francisco Bay from fluvial sources. Suspended sediment, optical backscatter, velocity data near the head of the estuary, and discharge data obtained from the output of a water balance model were used to generate continuous suspended sediment concentration records and compute loads to the Bay from the large Central Valley watershed. Sediment loads from small tributary watersheds around the Bay were determined using 235 station-years of suspended sediment data from 38 watershed locations, regression analysis, and simple modeling. Over 16 years, net annual suspended sediment load to the head of the estuary from its 154,000 km2 Central Valley watershed varied from 0.13 to 2.58 (mean = 0.89) million metric t of suspended sediment, or an average yield of 11 metric t/km2/yr. Small tributaries, totaling 8145 km2, in the nine-county Bay Area discharged between 0.081 and 4.27 (mean = 1.39) million metric t with a mean yield of 212 metric t/km2/yr. The results indicate that the hundreds of urbanized and tectonically active tributaries adjacent to the Bay, which together account for just 5% of the total watershed area draining to the Bay and provide just 7% of the annual average fluvial flow, supply 61% of the suspended sediment. The small tributary loads are more variable (53-fold between years compared to 21-fold for the inland Central Valley rivers) and dominated fluvial sediment supply to the Bay during 10 out of 16 yr. If San Francisco Bay is typical of other estuaries in active tectonic or climatically variable coastal regimes, managers responsible for water quality, dredging and reusing sediment accumulating in shipping channels, or restoring wetlands in the world's estuaries may need to more carefully account for proximal small urbanized watersheds that may dominate sediment supply.

McKee, L.J.; Lewicki, M.; Schoellhamer, D.H.; Ganju, N.K.

2013-01-01

230

Spatial Patterns of Suspended Sediment Yield in the Upper Indus River Basin, Northern Pakistan  

NASA Astrophysics Data System (ADS)

The Indus River is one of the world`s largest rivers in term of water discharge and sediment loads, and the backbone of Pakistan`s economy for agriculture and hydropower. Much of its flow originates in the mountains of the Himalayas, Karakoram and Hindu Kush. The suspended sediment load, which constitutes the main portion of the total load in mountain rivers, creates major water resources management problems such as siltation of reservoirs, damage to turbines, and a reduction in water quality. An understanding of the spatial pattern of suspended sediment yield in the upper Indus River basin is, therefore, essential for effective water resources development in northern Pakistan. Discharge and suspended sediment concentration records are available for 17 active and discontinued hydrological stations (with drainage areas ranging from 600 to 166,000 km2) operated by the Pakistan Water and Power Development Authority. The objective of this study is to delineate the spatial pattern of suspended sediment yield in the basin by analyzing the available hydrological database. Sediment yields have been calculated by constructing sediment rating curves. Physiographic characteristics, hydrologic regimes and climatic patterns of the basin have also been investigated. The results show that the upper Indus River basin can be subdivided into three regions based on suspended sediments yield. This division reflects the contrasting hydrological regimes of the basin. Region 1 comprises the high elevation, glacierized areas of the Karakoram Mountains in the northernmost part of the basin. This region extends downstream to Partab Bridge on the Indus River, and excludes areas around Nanga Parbat, which acts as a barrier to the monsoon. The sediments are mainly derived from the Shyok, Shigar, Hunza and Gilgit sub-basins during the period of increasing summer runoff in June. This runoff is caused by the melt of glaciers and permanent snow pack, and peaks in July and August, when almost the entire annual sediment load is transported. The mean annual sediment yield is greatest in the 28% glaciated Hunza River basin which accounts for more than 2800 t km-2 year-1. Region 2 is characterized by the sediment yields that result from an interaction of monsoon rains and glacier-melt. This region extends from Partab Bridge to Besham Qila. The Astore River produces the highest specific discharges in the basin, which are from southwest flanks of Nanga Parbat. Region 3 includes the area between Besham Qila and Tarbela Dam with the Gorband, Siran and Brandu tributaries. This part of the basin is mainly rain fed with little snow, and experience two types of rainfall: summer monsoon rains, and late winter and early spring rainfall produced by disturbances coming from the west that derive sediment on the hill slopes. This results in two separate peaks in the sediment loads, in March and July, respectively. This study can be further extended to construct a sediment budget for the upper Indus River. A sediment budget would result in a better understanding of the sediment dynamics by providing an accounting of the fluxes and fate of sediment in the drainage basin. The upper Indus exists in natural basin conditions without significant human impacts. As the sparse gauging network in this large basin is rapidly decreasing in density, the upper Indus basin represents a good case study for investigating the sediment dynamics in a data-sparse river as a contribution to the Prediction in Ungauged Basins (PUB) program.

Ali, K.; de Boer, D. H.; Martz, L. W.

2004-05-01

231

Cosmogenic nuclide-derived sediment budget of the Amazon basin  

NASA Astrophysics Data System (ADS)

Sediment gauging suggests that the annual sediment mass discharged into the main Amazon basin from the Andes and the cratonic shields is not in steady state with the mass discharged to the Atlantic Ocean. Here we use sediment production rates from cosmogenic 10Be in sediment to compare these with transport rates from river load gauging. About 1 million km2 or 95% of the total Andean area draining to the Amazon provide sediment to the central Amazon river with an averaged 10Be nuclide concentration of 5.0 +- 0.5x1e4 at/g(Qz). Average nuclide concentrations for Brazilian shield headwaters amount to 15.3 +- 1.2x1e4 at/g(Qz), and to 38.6 +- 2.4x1e4 at/g(Qz) for the Guyana shield headwaters, respectively. For the Andes, nuclide concentrations translate to an integrated Andean denudation rate of 0.35 ± 0.05 mm/yr. Sediment from the headwaters of the Brazilian and Guyana shields translate into very low denudation rates (0.02 and 0.01 mm/yr, respectively), as is expected for tectonically stable tropical highlands. These headwater 10Be nuclide concentrations and derived denudation rates can now be compared with those derived from central Amazon stream sediment including the main Amazon, which was sampled over ~1000 km from Manaus to Óbidos. Cosmogenic nuclide concentration analyses of several grain sizes (from 125 up to 800 µm) show large variations; we found that coarse-grained material records the nuclide signal of the cratonic shield areas, whereas the Andean signal is best represented by the fine sand fraction, which is preserved virtually unaltered over 1000s of km of sediment transport. In all central Amazon trunk stream samples and tributaries, the fine grain size fraction (125-250 µm) contains 10Be at 6.5 +- 1.2x1e4 at/g(Qz), which is similar to that of the Andean source areas. The integrated denudation rate from this fraction is 0.23 +- 0.04 mm/yr for the entire Amazon basin at Óbidos, which compares well with the mean Andean denudation rate of 0.35 +- 0.05 mm/yr. Coarse grain sizes (>500 µm) record the very low denudation rate of the cratonic shields. Given these low rates, the shields discharge only small amounts of sediment into the Amazon trunk stream. Multiplied with the area of the providing hinterland, we can use these erosion rates to calculate sediment mass budgets. The flux of sediment expected from cosmogenic nuclide-based denudation rates amounts to 540 Mt/yr at Óbidos. This flux compares to the total load of 1100 Mt/yr at Óbidos[1,2,3] as estimated from sediment gauging. This disparity is unexpected, as today at least 40% of the sediment discharged from the Andes is stored in floodplains[4]; a process not detected with cosmogenic 10Be. The longer denudation integration time scale of 8 kyr for cosmogenic nuclides possibly includes a period of drier climate than the wet conditions during the late Holocene, where a wetter modern climate possibly favors more rapid erosion in the Andes and more efficient sediment transport in the large rivers. 1 Gaillardet et al. (1997), Chemical Geology (142), 141-173. 2 Dunne et al. (1998), GSA Bulletin (110), 450-467. 3 Guyot et al. (2005), IAHS Publications (291), 1-8. 4 Guyot et al. (1996), IAHS Publications (236), 55-63.

Wittmann, Dr.; von Blanckenburg, Dr.; Guyot, Dr.; Maurice, Dr.; Kubik, Dr.

2009-04-01

232

Quantifying the origin of different sediment types in a catchment of the Southern French Alps by combining hydro-sedimentary records and fingerprinting  

NASA Astrophysics Data System (ADS)

Soil erosion and subsequent sediment supply to rivers are particularly massive and episodic in mountainous environments, such as in the Southern French Alps. Those processes typically lead to an increase in water turbidity and a rapid filling of reservoirs in downstream areas. This situation is particularly problematic in regions where reservoirs are used to provide clear water to hydroelectric power plants. Sediment source areas must first be delineated and sediment fluxes between hillslopes and the river system must be better understood to implement efficient sediment management. We therefore combined traditional monitoring techniques (i.e., installation of river gauges and sediment samplers in several subcatchments) and sediment fingerprinting using elemental geochemistry and fallout radionuclides as potential discriminant properties to quantify the supply of sediment provided by different lithological sources (i.e., black marls, marly limestones, conglomerates, Quaternary deposits) to the River Bléone (905 km²). Those analyses were conducted on different material types collected within the catchment (i.e. suspended and riverbed sediment), and at the catchment outlet (i.e. on a sequence of sections of a 3-m long sediment core). Sediment exports at the river catchment outlet (330±100 t km-2 yr-1) were mainly driven (80%) by the occurrence of widespread rainfall events (long duration, low intensities). In contrast, heavy, local and short duration storms generated high peak discharges and suspended sediment concentrations, but they were restricted to small upstream torrents. Our study (2007-2009) confirmed the important contribution of black marls (up to 70% at the flood scale) to sediment transported in rivers, although this substrate only occupies c. 10% of the total catchment surface. However, the contribution of other lithological sources varied at both intra- and inter-flood scales. Sediment exports generated by local convective storms were dominated by black marls/marly limestones. In contrast, widespread flood events that generate the bulk of annual sediment supply at the outlet were characterized by a more stable lithologic composition and by a larger contribution of limestones, Quaternary deposits and conglomerates, which corroborated the analysis of riverbed sediment. Finally, we found that black marls and marly limestone sources provided the main fraction of sediment analysed throughout the outlet core sequence (40 and 22 %, respectively, for the period 1962-2009). However, we also found evidence for the occurrence of major floods carrying large quantities of sediment originating from Quaternary deposits and conglomerates (25 and 16 %, respectively). The variability of sediment sources throughout the sequence may reflect the spatial variability of rainfall within the catchment, which in turn reflects its origin. This study emphasizes the importance of using archival data to validate the results of sediment fingerprinting studies conducted during short contemporary monitoring programmes.

Evrard, Olivier; Navratil, Oldrich; Ayrault, Sophie; Esteves, Michel; Legout, Cédric; Némery, Julien; Lefèvre, Irène; Bonté, Philippe

2013-04-01

233

A Record of Extreme Sedimentation Events in Central Idaho: Fire, Climate, and Changing Sediment Yields Over the Holocene  

NASA Astrophysics Data System (ADS)

In the central Idaho mountains, most of the annual runoff in small streams occurs with snowmelt, suggesting that most sediment transport would occur during high seasonal discharges with recurrence interval of perhaps a few years. A spate of recent major debris-flow events in small basins, however, implies that infrequent severe storms where mass movement threshold conditions are crossed are also be major contributors to sediment yields. This landscape is characterized by deeply weathered Idaho batholith granitic rocks, and slopes mantled by thick, poorly cohesive grussy sediment. An important control on debris-flow generation is fire, which dramatically lowers threshold conditions for surface runoff generation and also lowers the cohesive strength of slope sediment after roots decay. A series of storms culminating in intense rain on melting snow in January 1997 caused numerous colluvial failures, debris flows, and sediment-charged floods in South Fork Payette River tributaries, with the majority in either burned forested or unburned rangeland basins. This event produced sediment yields up to 44,000 Mg km-2 in ˜0.5 km2 basins, which equals several thousand years of background sediment yields (2.7-30 Mg km-2 yr-1) measured over a few decades of trapping and gauging in Idaho batholith watersheds, where major debris-flow events are not included (Clayton and Megahan, 1986). Recurrence intervals of ˜ 400 years for such extreme events would account for 10,000-yr average Idaho batholith sediment yields of ˜ 116 Mg km-2 yr-1 (Kirchner et al., Geology 29, 2001). Shaub (2001) found that of > 200 colluvial failures in the 1997 event in the South Fork Payette drainage, 75% occurred in burned areas. Over the last several decades, however, other large debris flows have been generated from unburned slopes by unusually intense summer convective storms and winter rain-on-snow events; we hypothesize that these events are more probable in warmer climates. Long-term effects on the main South Fork Payette channel are strongly dependent on sediment size transported as well as the total mass. Deposit characteristics from 10 alluvial fan sections in small basins show that of the total stratigraphic thickness, over 90% is probably or possibly related to fire. Of ˜ 54 depositional units within these fans, 5 fire-related debris-flow deposits account for ˜ 25% of the total stratigraphic thickness. Radiocarbon dating of these 5 large events show that all occurred between ˜ 750-1100 cal yr BP, corresponding to the "Medieval Warm Period", a time of increased fire-related sedimentation in Yellowstone and severe droughts in parts of the western USA. Most other large debris flows appear to occur during relatively warm episodes in Idaho. Event frequency reaches a maximum at other times corresponding to cooler climate (e.g., ˜ 300-500, 1100-1400, and 6600-7400 cal yr BP), but fan aggradation rates from these frequent small events are relatively low, and one well-preserved fan built over the earliest period provides a low average sediment yield comparable to modern background rates. These results suggest that infrequent large events account for the majority of sediment transport out of small mountain basins, and that sediment yields are strongly nonstationary over millennial timescales. Variations in climate and associated changes in fire regimes and storms exert a major control on the occurrence of extreme erosional events.

Meyer, G. A.; Pierce, J. L.

2003-12-01

234

77 FR 64463 - Annual Retail Trade Survey  

Federal Register 2010, 2011, 2012, 2013, 2014

...data covering annual sales, annual e- commerce sales, year-end inventories held...merchandise line sales, and percent of e-commerce sales to customers located outside...classification basis, annual sales, annual e-commerce sales, purchases, total and...

2012-10-22

235

75 FR 63804 - Annual Retail Trade Survey  

Federal Register 2010, 2011, 2012, 2013, 2014

...data covering annual sales, annual e-commerce sales, year-end inventories held...class of customer, and percent of e-commerce sales to customers located outside...classification basis, annual sales, annual e-commerce sales, purchases, total...

2010-10-18

236

76 FR 69239 - Annual Retail Trade Survey  

Federal Register 2010, 2011, 2012, 2013, 2014

...data covering annual sales, annual e-commerce sales, year-end inventories held...merchandise line sales, and percent of e-commerce sales to customers located outside...classification basis, annual sales, annual e-commerce sales, purchases, total...

2011-11-08

237

The accuracy of sediment loads when log-transformation produces nonlinear sediment load discharge relationships  

NASA Astrophysics Data System (ADS)

SummaryMost sediment loads are estimated from sediment-rating curves created by performing a linear least-square regression on log-transformed sediment load-discharge data. When log-transformed sediment load-discharge data plots result in concave or convex curves, such regressions under- or overestimate sediment loads. Conflicting results exist regarding the accuracy/utility of using nonlinear regression to estimate loads. A nonlinear regression technique (optimized/constrained two different ways) was compared with the linear regression method at 26 United States Geological Survey gaging stations throughout the Upper Mississippi River basin. Sensitivity analyses were conducted at two stations, one having a concave sediment load-discharge plot and one having a convex sediment load-discharge plot, to determine each rating curve's ability, based on varying amounts of data, to predict annual and cumulative suspended sediment yields. With a 5-year calibration dataset, a nonlinear maximized r2 statistic curve produced the best estimates for a station with a convex sediment load-discharge relationship, while a nonlinear load-constrained curve produced the best estimates for a station with a concave sediment load-discharge relationship. At both stations (using 5-year calibration datasets), annual yield errors ranged from -54% to 112%, while 15- and 18-year cumulative yield errors ranged from about -21% to 13%.

Crowder, D. W.; Demissie, M.; Markus, M.

2007-04-01

238

The capability of estuarine sediments to remove nitrogen: implications for drinking water resource in Yangtze Estuary.  

PubMed

Water in the Yangtze Estuary is fresh most of the year because of the large discharge of Yangtze River. The Qingcaosha Reservoir built on the Changxing Island in the Yangtze Estuary is an estuarine reservoir for drinking water. Denitrification rate in the top 10 cm sediment of the intertidal marshes and bare mudflat of Yangtze Estuarine islands was measured by the acetylene inhibition method. Annual denitrification rate in the top 10 cm of sediment was 23.1 ?mol m(-2) h(-1) in marshes (ranged from 7.5 to 42.1 ?mol m(-2) h(-1)) and 15.1 ?mol m(-2) h(-1) at the mudflat (ranged from 6.6 to 26.5 ?mol m(-2) h(-1)). Annual average denitrification rate is higher at mashes than at mudflat, but without a significant difference (p?=?0.084, paired t test.). Taking into account the vegetation and water area of the reservoir, a total 1.42?×?10(8) g N could be converted into nitrogen gas (N2) annually by the sediment, which is 97.7 % of the dissolved inorganic nitrogen input through precipitation. Denitrification in reservoir sediment can control the bioavailable nitrogen level of the water body. At the Yangtze estuary, denitrification primarily took place in the top 4 cm of sediment, and there was no significant spatial or temporal variation of denitrification during the year at the marshes and mudflat, which led to no single factor determining the denitrification process but the combined effects of the environmental factors, hydrologic condition, and wetland vegetation. PMID:24770927

Liu, Lin; Wang, Dongqi; Deng, Huanguang; Li, Yangjie; Chang, Siqi; Wu, Zhanlei; Yu, Lin; Hu, Yujie; Yu, Zhongjie; Chen, Zhenlou

2014-09-01

239

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  

USGS Publications Warehouse

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. The Pacolet River had a mean annual total nitrogen load of 99,780 kilograms per year and yield of 1.82 kilograms per hectare per year. Mean annual total phosphorus loads of 2,576; 9,404; and 11,710 kilograms per year and yields of 0.180, 0.313, and 0.213 kilograms per hectare per year were estimated at the South Pacolet, North Pacolet, and Pacolet River sites, respectively. Annually, the intervening subbasin of the Pacolet River contributed negligible amounts of total nitrogen and total phosphorus loads, and large losses of dissolved nitrate plus nitrite and orthophosphate loads were determined for the subbasin. Biological (algal) uptake in the two reservoirs in this intervening area was considered the likely explanation for the loss of these constituents. Estimated mean annual suspended-sediment loads were 21,190,000; 9,895,000; and 6,547,000 kilograms per year at the South Pacolet, North Pacolet, and Pacolet River sites, respectively. In the intervening Pacolet River subbasin, computed annual suspended-sediment loads were consistently negative, indicating large percentage losses in annual suspended-sediment load. Sedimentation processes in the two reservoirs are the most likely explanations for these apparent losses. At all sites, the winter season tended to have the highest estimated seasonal dissolved orthophosphate and dissolved nitrate plus nitrite fluxes, and the summer and fall seasons tended to have the lowest fluxes. The reverse pattern, however, was observed in the intervening drainage area in the Pacolet River where the lowest fluxes of dissolved orthophosphate and nitrate plus nitrite occurred during the winter and spring seasons and the highest occurred during the summer and fall seasons. Synoptic samples were collected during a high-flow event in August 2009 at eight sites that represented shoreline and minor tributary drainages. The South Pacolet River site was identified as contributing greater than 80 percent of the cumulative nutrient and sediment l

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

2011-01-01

240

Sediment Transport  

NSDL National Science Digital Library

Each student reviews a recent USGS publication detailing sediment transport data collection and reduction on the Yellowstone River. Using that report, they answer a series of questions about sediment transport and make some basic hydrologic and hydraulic calculations using data in the report. They also use USGS software to analyze cross-sections on the Yellowstone in a real world application. Designed for a geomorphology course

Karen Williams

241

Distribution and partitioning of heavy metals in estuarine sediment cores: implications for sediment quality standards Hydrology and Earth System Sciences, 6(6), 989998 (2002) EGS  

E-print Network

Distribution and partitioning of heavy metals in estuarine sediment cores: implications and partitioning of heavy metals in estuarine sediment cores and implications for the use of sediment quality.spencer@gl.rhul.ac.uk Abstract Total metal concentrations in surface sediments and historically contaminated sediments were

Paris-Sud XI, Université de

2002-01-01

242

An evaluation of sediment rating curves for estimating suspended sediment concentrations for subsequent flux calculations  

USGS Publications Warehouse

In the absence of actual suspended sediment concentration (SSC) measurements, hydrologists have used sediment rating (sediment transport) curves to estimate (predict) SSCs for subsequent flux calculations. Various evaluations of the sediment rating-curve method were made using data from long-term, daily sediment-measuring sites within large (>1 000 000 km2), medium ( 1000 km2), and small (<1000 km2) river basins in the USA and Europe relative to the estimation of suspended sediment fluxes. The evaluations address such issues as the accuracy of flux estimations for various levels of temporal resolution as well as the impact of sampling frequency on the magnitude of flux estimation errors. The sediment rating-curve method tends to underpredict high, and overpredict low SSCs. As such, the range of errors associated with concomitant flux estimates for relatively short time-frames (e.g. daily, weekly) are likely to be substantially larger than those associated with longer time-frames (e.g. quarterly, annually) because the over- and underpredictions do not have sufficient time to balance each other. Hence, when error limits must be kept under ??20%, temporal resolution probably should be limited to quarterly or greater. The evaluations indicate that over periods of 20 or more years, errors of <1% can be achieved using a single sediment rating curve based on data spanning the entire period. However, somewhat better estimates for the entire period, and markedly better annual estimates within the period, can be obtained if individual annual sediment rating curves are used instead. Relatively accurate (errors annual suspended sediment fluxes can be obtained from hydrologically based monthly measurements/samples. For 5-year periods or longer, similar results can be obtained from measurements/samples collected once every 2 months. In either case, hydrologically based sampling, as opposed to calendar-based sampling is likely to limit the magnitude of flux estimation errors. Published in 2003 by John Wiley and Sons, Ltd.

Horowitz, A.J.

2003-01-01

243

Water and sediment quality assessment of the Axios River and its coastal environment  

NASA Astrophysics Data System (ADS)

The Axios River (Axios R.) receives substantial loads of nutrients, heavy metals and other compounds, resulting from anthropogenic activities within its catchment. Long-term trends in nutrients were assessed. Dissolved and particulate fluxes of nutrients and selected metals to the Thermaikos Gulf were calculated and finally, data evaluation with water and sediment quality criteria was performed. Dissolved nutrient concentrations exhibited intra-annual variations related to the agricultural practices of the drainage area with elevated autumn-winter NO 3 concentrations (related to fertilizers applied early spring) and high levels of total phosphorous in the summer attributed to point source pollution. Long-term inter-annual variability showed a 2.5-fold increase in nitrate concentration, coupled with a 3-fold decrease in water discharge. Elevated concentrations of dissolved Pb and As have been observed in the Axios R., and freshwater quality criteria for Pb were exceeded. Stream sediments exhibited high contents for Zn, Cr, Pb, and As, mainly originating in tailings and industrial effluents. On the other hand, a considerable portion of the heavy metals is derived from the weathering of ultra-mafic ophiolite complexes. Similar patterns were observed in the Thermaikos Gulf sediment chemistry; the geochemical signatures of the Axios and Aliakmon Rivers (Aliakmon R.), in respect to their contribution in heavy metals, were identified, as well as the impact of the Thessaloniki city. Quality criteria for both river and marine sediments were violated for As and Cr. Overall, the water and sediment quality of the Axios R. and the Thermaikos Gulf have been impacted by anthropogenic activities in the hinterland. The coastal waters and sediments do not appear to pose any threat to human health and aquatic life, however, the need for regular monitoring is highly recommended.

Karageorgis, A. P.; Nikolaidis, N. P.; Karamanos, H.; Skoulikidis, N.

2003-11-01

244

Temporal variations of water and sediment fluxes in the Cointzio river basin, central Mexico  

NASA Astrophysics Data System (ADS)

The STREAMS program (Sediment TRansport and Erosion Across MountainS) was launched in 2006 to study suspended sediment dynamics in mountainous areas. Two watersheds were selected as part of the program: the Bléone river basin in the French Alps, and the Cointzio river basin (636 km2), located in the mountainous region of Michoacán, in central Mexico. The volcanic soils of the Cointzio catchment undergo important erosion processes, especially during flashflood events. Thus, a high-frequency monitoring of sediment transport is highly required. The poster presents the high-frequency database obtained from the 2008 hydrological season at the Santiago Undameo gauged station, located at the basin's outlet. Suspended Sediment Concentration (SSC) was estimated every 10 minutes by calibrating turbidity measurements with bottle sampling acquired on a double-daily basis. Water discharge time-series was approximated with continuous water-level measurements (5 minutes time-step), and a stage-discharge rating curve. Our investigation highlights the influence of sampling frequency on annual water and sediment fluxes estimate. A daily or even a weekly water-level measurement provides an unexpectedly reliable assessment of the seasonal water fluxes, with an under-estimation of about 5 % of the total flux. Concerning sediment fluxes, a high-frequency SSC survey appears to be necessary. Acquiring SSC data even twice a day leads to a significant (over 30 %) under-estimation of the seasonal sediment load. These distinct behaviors can be attributed to the fact that sediment transport almost exclusively occurs during brief night flood events, whereas exfiltration on the watershed always provides a base flow during the daily water-level measurements.

Duvert, C.; Gratiot, N.; Navratil, O.; Esteves, M.; Prat, C.; Nord, G.

2009-04-01

245

A watershed-scale assessment of cost-effectiveness of sediment abatement with flow diversion terraces.  

PubMed

Soil conservation beneficial management practices (BMPs) are effective at controlling soil loss from farmlands and minimizing water pollution in agricultural watersheds. However, costs associated with implementing and maintaining these practices are high and often deter farmers from using them. Consequently, it is necessary to conduct cost-benefit analysis of BMP implementation to assist decision-makers with planning to provide the greatest level of environmental protection with limited resources and funding. The Soil and Water Assessment Tool (SWAT) was used to evaluate the efficacy of flow diversion terraces (FDT) in abating sediment yield at the outlet of Black Brook Watershed (BBW), northwestern New Brunswick. Different FDT-implementation scenarios were expressed as the ratio of land area protected by FDT to the total cultivated area. From this analysis, we found that average annual sediment yield decreased exponentially with increased FDT protection. When the proportion of FDT-protected areas was low, sediment reductions caused by FDT increased sharply with increasing use of FDT. Similarly, marginal sediment yield abatement costs (dollar per tonne of sediment reduction) increased exponentially with increasing proportion of FDT-protected area. The results indicated that increasing land protection with FDT from 6 to 50% would result in a reduction of about 2.1 tonne ha(-1) yr(-1) and costs of sediment reduction increased from $7 to $12 per tonne. Increasing FDT-protected cropland from 50 to 100%, a reduction of about 0.9 tonne of sediment ha(-1) yr(-1) would occur and the costs would increase from $12 to $53 per tonne of sediment yield reduction. PMID:20048309

Yang, Qi; Zhao, Zhengyong; Benoy, Glenn; Chow, Thien Lien; Rees, Herb W; Bourque, Charles P-A; Meng, Fan-Rui

2010-01-01

246

Muted responses of streamflow and suspended sediment flux in a wildfire-affected watershed  

NASA Astrophysics Data System (ADS)

In August 2003 a severe wildfire burnt 62% of Fishtrap Creek, a 158 km2 watershed in central British Columbia, Canada. Streamflows were obtained for the period 1980-2010 and suspended sediment fluxes were determined for the period 2004-2010 for Fishtrap Creek and these were compared to data for nearby Jamieson Creek, which was not affected by the wildfire. Peak streamflows in Fishtrap Creek after the wildfire were not significantly higher than before the wildfire, although total annual runoff had increased. Perhaps the most important change in streamflows following the wildfire was that peak flows associated with the annual freshet occurred earlier in the year (by ca. 2 weeks). Following the wildfire, monthly total suspended sediment fluxes peaked in April in Fishtrap Creek and May in Jamieson Creek, which reflects the change in timing of peak streamflows in Fishtrap. Specific suspended sediment yields were low in the first year following the wildfire (2004), and peak values for the 2004-2010 monitoring period occurred in 2006. Average specific suspended sediment yields over the monitoring period were similar for both watersheds at 2.8 and 2.9 t km- 2 year- 1 for Fishtrap and Jamieson watersheds, respectively. The muted responses of streamflows and suspended sediment fluxes following this severe wildfire are due to the lack of winter precipitation and the low intensities of summer rainfall events in the first year following the wildfire. Greater winter precipitation and associated snowmelt in subsequent years coincided with vegetation recovery. The major changes in the wildfire-affected watershed were increased bank erosion and channel migration due to a loss of root strength and cohesion, which occurred 3-5 years after the fire. This work demonstrates that the hydrological and geomorphological responses of watersheds to wildfires are a function of the severity of the wildfire and the timing and nature of driving forces (i.e. rainfall intensity, winter precipitation and snowmelt) during the progression of vegetation recovery.

Owens, P. N.; Giles, T. R.; Petticrew, E. L.; Leggat, M. S.; Moore, R. D.; Eaton, B. C.

2013-11-01

247

Coupling sediment flow-paths with organic carbon dynamics across a Mediterranean catchment  

NASA Astrophysics Data System (ADS)

Terrestrial sedimentation buries large amounts of organic carbon (OC) annually, contributing to the terrestrial carbon sink. The temporal significance of this sink will strongly depend on the attributes of the depositional environment, but also on the characteristics of the OC reaching these sites and its stability upon deposition. The goal of this study was to characterise the OC during transport and stored in the depositional settings of a medium sized catchment (111 km2) in SE Spain, to better understand how soil erosion and sediment transport processes determine catchment scale OC redistribution. Total Organic Carbon (TOC), Mineral-Associated Organic Carbon (MOC), Particulate Organic Carbon (POC), Total Nitrogen (N) and particle size distributions were determined for soils (i), suspended sediments (ii) and sediments stored in a variety of sinks such as sediment wedges behind check-dams (iii), channel bars (iv), a small delta in the conjunction of the channel and a reservoir downstream (v) and the reservoir at the outlet of the catchment (vi). The data show that the OC content of sediments was approximately half of that in soils (9.42 ± 9.01 g kg-1 vs. 20.45 ± 7.71 g kg-1, respectively) with important variation between sediment deposits. Selectivity of mineral and organic material during transport and deposition increased in a downstream direction. The OC mineralisation, burial or formation occurred in sediments depending on their transport process and on the post-sedimentary conditions. Upstream sediments showed low OC contents because they were partially mobilised by non-selective erosion processes affecting deeper soil layers. We hypothesise that the relatively short transport distances, the effective preservation of OC in micro-aggregates and the burial of sediments in the alluvial wedges give rise to low OC mineralisation, with C : N ratios similar to those in soils. Deposits in middle stream areas (fluvial bars) were enriched in sand, selected upon deposition and had low OC concentrations. Downstream, sediment transported over longer distances was more selected, dominated by silt and clay fractions and associated with OC. Overall, the study shows that OC redistribution in the studied catchment is highly complex, and that transport and deposition processes have a strong effect on the concentration and quality of OC found at the different depositional settings, with important consequences for the temporal stability of the buried OC and in turn for the OC budget.

Boix-Fayos, C.; Nadeu, E.; Quiñonero, J. M.; Martínez-Mena, M.; Almagro, M.; de Vente, J.

2014-05-01

248

Yaquina Bay, Oregon, Intertidal Sediment Temperature Database, 1998 - 2006.  

EPA Science Inventory

Detailed, long term sediment temperature records were obtained and compiled in a database to determine the influence of daily, monthly, seasonal and annual temperature variation on eelgrass distribution across the intertidal habitat in Yaquina Bay, Oregon. Both currently and hi...

249

78 FR 68023 - Annual Wholesale Trade Survey  

Federal Register 2010, 2011, 2012, 2013, 2014

...collect data covering annual sales, e- commerce sales, purchases, total operating...will collect data covering sales, e-commerce sales, year-end inventories held...collect data covering annual sales, e-commerce sales, year-end inventories...

2013-11-13

250

76 FR 64894 - Annual Wholesale Trade Survey  

Federal Register 2010, 2011, 2012, 2013, 2014

...collect data covering annual sales, e-commerce sales, purchases, total operating...will collect data covering sales, e- commerce sales, year-end inventories held...collect data covering annual sales, e-commerce sales, year-end inventories...

2011-10-19

251

Post–Little Ice Age record of coarse and fine clastic sedimentation in an Alaskan proglacial lake  

Microsoft Academic Search

Many assessments of glacial sediment yield rely solely on mea- surements of fine-grained suspended sediment. We show that sus- pended sediment contributes ,20% of the total clastic sediment discharge into Iceberg Lake, an Alaskan proglacial lake. Drainage of this lake in 1999 exposed outcrops of varved lacustrine sediment that record suspended sediment deposition. Since a Little Ice Age highstand two

Michael G. Loso; Robert S. Anderson; Suzanne P. Anderson

2004-01-01

252

Large-scale suspended sediment transport and sediment deposition in the Mekong Delta  

NASA Astrophysics Data System (ADS)

Sediment dynamics play a major role in the agricultural and fishery productivity of the Mekong Delta. However, the understanding of sediment dynamics in the delta, one of the most complex river deltas in the world, is very limited. This is a consequence of its large extent, the intricate system of rivers, channels and floodplains, and the scarcity of observations. This study quantifies, for the first time, the suspended sediment transport and sediment deposition in the whole Mekong Delta. To this end, a quasi-2D hydrodynamic model is combined with a cohesive sediment transport model. The combined model is calibrated using six objective functions to represent the different aspects of the hydraulic and sediment transport components. The model is calibrated for the extreme flood season in 2011 and shows good performance for 2 validation years with very different flood characteristics. It is shown how sediment transport and sediment deposition is differentiated from Kratie at the entrance of the delta on its way to the coast. The main factors influencing the spatial sediment dynamics are the river and channel system, dike rings, sluice gate operations, the magnitude of the floods, and tidal influences. The superposition of these factors leads to high spatial variability of sediment transport, in particular in the Vietnamese floodplains. Depending on the flood magnitude, annual sediment loads reaching the coast vary from 48 to 60% of the sediment load at Kratie. Deposited sediment varies from 19 to 23% of the annual load at Kratie in Cambodian floodplains, and from 1 to 6% in the compartmented and diked floodplains in Vietnam. Annual deposited nutrients (N, P, K), which are associated with the sediment deposition, provide on average more than 50% of mineral fertilizers typically applied for rice crops in non-flooded ring dike floodplains in Vietnam. Through the quantification of sediment and related nutrient input, the presented study provides a quantitative basis for estimating the benefits of annual Mekong floods for agriculture and fishery, and is an important piece of information with regard to the assessment of the impacts of deltaic subsidence and climate-change-related sea level rise on delta morphology.

Manh, N. V.; Dung, N. V.; Hung, N. N.; Merz, B.; Apel, H.

2014-08-01

253

The role of overbank floodplain sedimentation in catchment contaminant budgets  

Microsoft Academic Search

Overbank sedimentation on river floodplains can result in significant reduction of the suspended sediment load transported by a river and can thus represent an important component of the catchment sediment budget. Such conveyance losses will also exert an important influence on sediment-associated contaminant fluxes and budgets. This contribution reports the results of a study of sediment-associated contaminants (i.e. total-P, Cr,

D. E. Walling; P. N. Owens

2003-01-01

254

Linking suspended sediment transport metrics with fish functional traits in the Northwestern Great Plains (Invited)  

NASA Astrophysics Data System (ADS)

Loss of ecological integrity due to excessive suspended sediment in rivers and streams is a major cause of water quality impairment in the United States. Although 32 states have developed numeric criteria for turbidity or suspended solids, or both according to the USEPA (2006), criteria is typically written as a percent exceedance above background and what constitutes background is not well defined. Defining a background level is problematic considering suspended sediments and related turbidity levels change with flow stage and season, and limited scientific data exists on relationships between sediment exposure and biotic response. Current assessment protocols for development of sediment total maximum daily loads (TMDLs) lack a means to link temporally-variable sediment transport rates with specific losses of ecological functions as loads increase. This study, within the in Northwestern Great Plains Ecoregion, co-located 58 USGS gauging stations with existing flow and suspended sediment data, and fish data from federal and state agencies. Suspended sediment concentration (SSC) transport metrics were quantified into exceedance frequencies of a given magnitude, duration as the number of consecutive days a given concentration was equaled or exceeded, dosage as concentration x duration, and mean annual suspended sediment yields. A functional traits-based approach was used to correlate SSC transport metrics with site occurrences of 20 fish traits organized into four main groups: preferred rearing mesohabitat, trophic structure, feeding habits, and spawning behavior. Negative correlations between SSC metrics and trait occurrences were assumed to represent potential conditions for impairment, specifically identifying an ecological loss by functional trait. Potential impairment conditions were linked with presence of the following traits: habitat preferences for stream pool and river shallow waters; feeding generalists, omnivores, piscivores; and several spawning behaviors. Using these results, TMDL targets were proposed such as < 19 mg/l SSC and 1,500 mg/l-day dosage at the 95% recurrence frequency for feeding generalists and omnivores. In general, traits correlated with: 1) a broad range of SSC exceedance frequencies and flow stages, 2) exceedance frequencies near 90-95% occurring at moderate flow stages; and 3) exceedance frequencies near 0.01-10 % occurring during floods. Unstable channels were found to be greater in transported suspended sediment than stable channels over a range of concentration exceedance frequencies, and likely influence physical habitat quality. Pool-preference and gravel spawner traits were greater in stable channels than unstable channels. Overall, a functional traits-based approach utilizing concentration-duration-frequency characteristics of suspended sediment transport was successful in identifying potential “targets” for biological impairment due to excessive sediment, and will aid in developing sediment TMDLs.

Schwartz, J. S.; Simon, A.; Klimetz, L.

2009-12-01

255

CAUSATIVE FACTORS AND VARIATION OF SEDIMENT YIELDS IN KENTUCKY.  

USGS Publications Warehouse

Precipitation, topography, runoff, soils, and land use are the major causative factors of sediment yield in Kentucky. The variability and interaction of these factors directly affects the amount and type of sediment yields. Sediment yield and size data were collected during 1942-45 and 1951-81 throughout the five major physiographic regions of Kentucky and at selected stations on the main stem of the Ohio River. The highest average annual suspended-sediment discharge, the average percent sand in suspended sediment, and the bedload discharge for selected stations were noted in the article.

Sholar, Clyde J.

1984-01-01

256

Notes on sedimentation activities calendar year 1990  

USGS Publications Warehouse

This report is a digest of information furnished by Federal agencies conducting sedimentation investigations. The decision to publish the report was made in 1946, from a proposal by the Chairman of the Federal Interagency River Basin Committee, Subcommittee on Sedimentation. The subcommittee approved the proposal and agreed to issue this report as a means of effecting better coordination of the work of various Federal agencies in the field of sedimentation. The report was issued on a quarterly basis in 1946 and 1947, from 1948 to 1953 reports were issued every 6 months, and from 1954 to the present, the report has been issued annually.

U.S. Interagency Advisory Committee on Water Data- Subcommittee on Sedimentation

1991-01-01

257

Notes on sedimentation activities calendar year 1992  

USGS Publications Warehouse

This report is a digest of information furnished by Federal agencies conducting sedimentation investigations. The decision to publish the report was made in 1946, from a proposal by the Chairman of the Federal Interagency River Basin Committee, Subcommittee on Sedimentation. The subcommittee approved the proposal and agreed to issue this report as a means of effecting better coordination of the work of various Federal agencies in the field of sedimentation. The report was issued on a quarterly basis in 1946 and 1947, from 1948 to 1953 reports were issued every 6 months, and from 1954 to present, the report has been issued annually.

U.S. Interagency Advisory Committee on Water Data- Subcommittee on Sedimentation

1994-01-01

258

Notes on sedimentation activities calendar year 1991  

USGS Publications Warehouse

This report is a digest of information furnished by Federal agencies conducting sedimentation investigations. The decision to publish the report was made in 1946, from a proposal by the Chairman of the Federal Interagency River Basin Committee, Subcommittee on Sedimentation. The subcommittee approved the proposal and agreed to issue this report as a means of effecting better coordination of the work of various Federal agencies in the field of sedimentation. The report was issued on a quarterly basis in 1946 and 1947, from 1948 to 1953 reports were issued every 6 months, and from 1954 to the present, the report has been issued annually.

U.S. Interagency Advisory Committee on Water Data- Subcommittee on Sedimentation

1992-01-01

259

ORIGINAL PAPER Five thousand years of sediment transfer in a high arctic  

E-print Network

in annually laminated sediments from Lower Murray Lake, Ellesmere Island, Nunavut, Canada Timothy L. Cook � Ellesmere Island, Nunavut Canada (81°210 N, 69°320 W) contain annual laminations (varves) that provide Á Arctic Á Lake sediments Á Ellesmere Island Introduction The High Arctic, surrounded by sea ice

Massachusetts at Amherst, University of

260

ORIGINAL PAPER Five thousand years of sediment transfer in a high arctic  

E-print Network

in annually laminated sediments from Lower Murray Lake, Ellesmere Island, Nunavut, Canada Timothy L. Cook � in Lower Murray Lake, north- ern Ellesmere Island, Nunavut Canada (81°210 N, 69°320 W) contain annual Á Arctic Á Lake sediments Á Ellesmere Island Introduction The High Arctic, surrounded by sea ice

Long, Bernard

261

Enrollment Statistics -Engineering TOTAL M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total  

E-print Network

Enrollment Statistics - Engineering TOTAL M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total Spring 2000 Freshmen 256 8 3 11 19 15 Senior 806 11 9 20 56 34 90 158 26 184 143 16 159 124 18 142 159 24 183 9 3 12 14 2 16 BS Total 1727 MS

Hayes, Jane E.

262

Total protein  

MedlinePLUS

The total protein test measures the total amount of two classes of proteins found in the fluid portion of your blood. These are albumin and globulin. Proteins are important parts of all cells and tissues. ...

263

Nutrient and sediment concentrations and corresponding loads during the historic June 2008 flooding in eastern Iowa  

USGS Publications Warehouse

A combination of above-normal precipitation during the winter and spring of 2007-2008 and extensive rainfall during June 2008 led to severe flooding in many parts of the midwestern United States. This resulted in transport of substantial amounts of nutrients and sediment from Iowa basins into the Mississippi River. Water samples were collected from 31 sites on six large Iowa tributaries to the Mississippi River to characterize water quality and to quantify nutrient and sediment loads during this extreme discharge event. Each sample was analyzed for total nitrogen, dissolved nitrate plus nitrite nitrogen, dissolved ammonia as nitrogen, total phosphorus, orthophosphate, and suspended sediment. Concentrations measured near peak flow in June 2008 were compared with the corresponding mean concentrations from June 1979 to 2007 using a paired t test. While there was no consistent pattern in concentrations between historical samples and those from the 2008 flood, increased flow during the flood resulted in near-peak June 2008 flood daily loads that were statistically greater (p < 0.05) than the median June 1979 to 2007 daily loads for all constituents. Estimates of loads for the 16-d period during the flood were calculated for four major tributaries and totaled 4.95 x 10(7) kg of nitrogen (N) and 2.9 x 10(6) kg of phosphorus (P) leaving Iowa, which accounted for about 22 and 46% of the total average annual nutrient yield, respectively. This study demonstrates the importance of large flood events to the total annual nutrient load in both small streams and large rivers.

Hubbard, L.; Kolpin, D.W.; Kalkhoff, S.J.; Robertson, D.M.

2011-01-01

264

Modern transport and deposition of settling particles in the northern South China Sea: Sediment trap evidence adjacent to Xisha Trough  

NASA Astrophysics Data System (ADS)

Studies on modern sediment transport and deposition, especially studies analyzing settling particles collected with sediment traps, have rarely been carried out in the northern South China Sea. Using sediment trap time series data from Site XS1 (17°24.5?N, 110°55.0?E, water depth 1690 m) adjacent to the Xisha Trough, variations in sediment source through time have been reconstructed. These observations include total particle flux (TPF) and current data, grain size distributions, and clay mineral compositions obtained from two sediment traps deployed in 500 m and 1500 m water depth, respectively. Time series records at Site XS1 changed seasonally for both sampled layers. TPF in the lower layer (426 mg/m2/d) was several times that of the upper layer (113 mg/m2/d) and is affected by lateral transport. However, mean grain size (Mz) of the upper layer is greater that of the lower layer (29 vs10 ?m) due to contributions from biogenic materials. There are no clear seasonal changes in clay mineral assemblage in either the upper or lower layers. The annual percentages of four main clay minerals were 82-83% illite, 7-9% kaolinite, 6-8% chlorite and 1-3% smectite. Taiwan was the dominant sediment source (42-74%), while sediment contributions from the Red River and Annamite Chain account for 23-53% and 0-15%, respectively. Sediment supply from Taiwan could be explained by deep water current flow, while coastal currents may aid sediment transport from the Red River and small mountainous rivers of central Vietnam.

Liu, Jianguo; Clift, Peter D.; Yan, Wen; Chen, Zhong; Chen, Han; Xiang, Rong; Wang, Dongxiao

2014-11-01

265

Flood generation and sediment transport in experimental catchments affected by land use changes in the central Pyrenees  

NASA Astrophysics Data System (ADS)

SummaryThree small catchments (<2.5 km 2 in size) were monitored in the Central Spanish Pyrenees to analyse the hydrological and geomorphological consequences of different land covers under the same climate scenario: (i) the San Salvador catchment represents a dense, undisturbed forest environment; (ii) the Arnás catchment corresponds to an old, abandoned cultivated area subjected to colonisation by plants; and (iii) the Araguás catchment consists in part of active badlands. The obtained results demonstrate that plant cover is a key factor, influencing (i) the seasonality and intensity of floods, (ii) the annual volume of discharge, and (iii) the suspended sediment concentration, total sediment yield and proportions of different types of sediment. The forested catchment tends to generate floods in late winter and spring, when the water table is close to the surface, and flood hydrographs are generally gentle, with solutes largely prevailing over suspended sediment. The old agricultural catchment produces in average twice the number of floods as that recorded in the forested catchment, with the highest floods recorded in autumn and spring; this catchment behaves as a complex mosaic, with a large spatial and temporal variability in terms of both sediment- and runoff-contributing areas; in addition, suspended sediment is equal to solutes, and bedload reaches a relatively high importance. Finally, the badland catchment reacts to all rainstorm events throughout the year, with a high suspended-sediment load. Sediment outputs from the Araguás catchment are two orders of magnitude higher than in the Arnás and San Salvador catchments. Suspended sediment concentrations exceed 300 g l -1 in the Araguás catchment, whereas they rarely exceed 20 g l -1 in the Arnás and rarely 1.5 g l -1 in the San Salvador catchment.

García-Ruiz, José M.; Regüés, David; Alvera, Bernardo; Lana-Renault, Noemí; Serrano-Muela, Pilar; Nadal-Romero, Estela; Navas, Ana; Latron, Jérôme; Martí-Bono, Carlos; Arnáez, José

2008-07-01

266

From deposition to erosion: spatial and temporal variability of sediment sources, storage, and transport in a small agricultural watershed  

USGS Publications Warehouse

The spatial and temporal variability of sediment sources, storage, and transport were investigated in a small agricultural watershed draining the Coast Ranges and Sacramento Valley in central California. Results of field, laboratory, and historical data analysis in the Willow Slough fluvial system document changes that transformed a transport-limited depositional system to an effective erosion and transport system, despite a large sediment supply. These changes were caused by a combination of factors: (i) an increase in transport capacity, and (ii) hydrologic alteration. Alteration of the riparian zone and drainage network pattern during the past ~ 150 years included a twofold increase in straightened channel segments along with a baselevel change from excavation that increased slope, and increased sediment transport capacity by ~ 7%. Hydrologic alteration from irrigation water contributions also increased transport capacity, by extending the period with potential for sediment transport and erosion by ~ 6 months/year. Field measurements document Quaternary Alluvium as a modern source of fine sediment with grain size distributions characterized by 5 to 40% fine material. About 60% of an upland and 30% of a lowland study reach incised into this deposit exhibit bank erosion. During this study, the wet 2006 and relatively dry 2007 water years exhibited a range of total annual suspended sediment load spanning two orders of magnitude: ~ 108,500 kg/km2/year during 2006 and 5,950 kg/km2/year during 2007, only 5% of that during the previous year. Regional implications of this work are illustrated by the potential for a small tributary such as Willow Slough to contribute sediment – whereas large dams limit sediment supply from larger tributaries – to the Sacramento River and San Francisco Bay Delta and Estuary. This work is relevant to lowland agricultural river–floodplain systems globally in efforts to restore aquatic and riparian functions and where water quality management includes reducing fine sediment contributions that can couple with other pollutants.

Florsheim, J.L.; Pellerin, B.A.; Oh, N.H.; Ohara, N.; Bachand, P.A.M.; Bachand, Sandra M.; Bergamaschi, B.A.; Hernes, P.J.; Kavvas, M.L.

2011-01-01

267

Sedimental Reasons  

NSDL National Science Digital Library

Visitors to this site can view satellite imagery and read an account of how remote sensing was employed to evaluate the extent of flooding and sediment load in rivers on the coastal plain of North Carolina as a result of Hurricane Floyd in September, 1999. This feature is part of NASA's Earth Observatory, a publication that focuses on Earth's climate and environmental change.

268

Hydromorphological and biological factors influencing sediment and phosphorus loss via bank erosion in small lowland rural streams in Denmark  

NASA Astrophysics Data System (ADS)

Bank erosion was measured at 91 stream banks located in 15 Danish rural 1st and 2nd order streams over a 2-year period. Our aims were firstly to examine factors controlling spatial variation in bank erosion, secondly to estimate sediment and phosphorus (P) loss via bank erosion. The overall mean bank erosion rate was 11 mm year-1. Bank erosion rate over the 2-year period was significantly related to a number of site-specific characteristics, including bank angle, bank vegetation cover, overhanging bank and estimated stream power. An empirical model for bank erosion based on these descriptive variables yielded a 55% explanation of the observed spatial variation in bank erosion rate. Bank erosion was higher at the lower 50-cm bank section (20 mm year-1) than at the upper bank (6 mm year-1). Cattle fencing in grazed areas and buffer zones with riparian woodland lowered bank erosion rates. We found that total P content of bank material was high (0·64 g P kg-1) and at the same level as found in agricultural topsoil along the streams. The overall annual catchment loss of bank-derived clay-silt sediment and total P to streams amounted to 58-72 kg sediment ha-1 and 0·23-0·28 kg P ha-1, respectively. In comparison, the mean annual suspended sediment (SS) and total P losses from 14 similar sized Danish agricultural catchments were 122 kg SS ha-1 and 0·58 kg P ha-1 over the 2-year study period. Thus, bank erosion seems to be a major contributor of suspended sediment and P in this type of small channelized lowland stream. Copyright

Laubel, A.; Kronvang, B.; Hald, A. B.; Jensen, C.

2003-12-01

269

Temporal trends in fluvial-sediment discharge in Ohio, 1950-1987  

USGS Publications Warehouse

Long-term fluvial-sediment records of annual suspended-sediment discharge data are available for eight daily suspended-sediment stations operated in Ohio. Graphical and statistical analyses of long-term sediment records indicate that, in general, no long-term (>3- to 5-year) trends are readily apparent in the relation between annual mean suspended-sediment discharge and water discharge in Ohio; however, some short-term, year-to-year changes in that relation occur for Ohio streams. Double-mass curves for five daily suspended-sediment stations and seasonal Kendall analysis of data from eight daily suspended-sediment stations clearly illustrate the lack of any discernible changes in the suspended-sediment-discharge/water-discharge relation or in suspended-sediment concentration for most Ohio streams over the past 36 years. -from Author

Hindall, S.M.

1991-01-01

270

Suspended sediment transport in the Ganges-Brahmaputra River System, Bangladesh  

E-print Network

discharge; 80% of the annual water discharge and 95% of the annual sediment load is debouched during the four summer monsoon months (Goodbred, 2003). The combination of the rivers' high sediment load, annual overbank flooding, and subsiding sub... in the foreset beds (Michels et al., 1998), and 25% is transported to the Swatch of No Ground Canyon which incises the sub-aqueous delta (Goodbred and Kuehl, 1999). An additional 1-2% of the annual sediment load contributes to the prograding subaerial delta...

Rice, Stephanie Kimberly

2009-05-15

271

Fremont Lake, Wyoming--some aspects of the inflow of water and sediment  

USGS Publications Warehouse

Fremont Lake is a large (20.6 sq km), deep lake (185 m) in western Wyoming. Average annual inflow of water is about 5.1 cu meters/sec, and this discharge is equaled or exceeded about 23% of the time. Annual instantaneous peak flows of Pine Creek usually exceed 30 cu m/sec and the 100-year flood is about 80 cu m/sec. About 800 tons of sediment are delivered to the lake annually; annual deposition of sediment in the northern lake area throughout the last 10,000 years about equals contemporary values of sediment inflow. Only small quantities of fine-gradient sediment are transported beyond the delta at the northern end of the lake. Current rates of deposition in the delta are about 1 to 3 mm/yr. Sediment in the delta generally is sand size; elsewhere in the lake, sediment generally is clay and silt size. (USGS)

Emmett, W.W.; Averett, R.C.

1989-01-01

272

Mercury distribution in sediment profiles of six Louisiana Lakes.  

PubMed

A study was conducted of six Louisiana Lakes to examine the relationship between sediment properties including mercury content and health advisories associated with mercury levels in fish. Comparison was made between three lakes with health advisories (Black Lake, Chicot Lake, and Henderson Lake) and three lakes where the levels of mercury in fish are below health advisory levels (False River, Lake St. John, and Miller Lake). Three sediment core samples were collected from each lake and sectioned into 2-cm increments to a depth of 20 cm. Sediment properties measured in each depth increment of the sediment profile included total mercury, 137Cs activity (for sedimentation rate), and sediment organic matter content. Of the lakes studied, those lakes that have health advisories for mercury tended to have higher total mercury contents, usually higher sediment organic matter contents, and higher sedimentation rates than sediments in lakes where health advisories for mercury are not issued. PMID:11460323

Gambrell, R P; DeLaune, R D; Patrick, W H; Jugsujinda, A

2001-05-01

273

Mercury Concentrations in Coastal Sediment from Younger Lagoon, Central California  

NASA Astrophysics Data System (ADS)

Younger Lagoon Reserve, located in northern Monterey Bay, is one of the few relatively undisturbed wetlands that remain along the Central Coast of California. This lagoon system provides protected habitat for more than 100 bird species and for populations of fish, mammals, and invertebrates. Total mercury (HgT) concentrations in water within Younger Lagoon appear to vary with rainfall conditions and range from about 5-15 pM. These concentrations are similar to HgT in water from six nearby lagoon systems. However, Younger Lagoon contains elevated concentrations of dissolved organic carbon (~1 mM) and monomethylmercury (MMHg, ~1 pM) relative to our comparison lagoon sites (DOC < 0.5 mM and MMHg < 0.5 pM). We attribute Younger Lagoon's high DOC and MMHg to its restricted connection to the ocean and minor riverine contribution. Coastal lagoons in this region typically form at the mouth of streams. They behave as small estuaries during the wet season when surface water discharge keeps the mouth of the stream open to the ocean, and then transition into lagoons in the dry season when a sand berm develops and effectively cuts off surface water exchange. At Younger Lagoon, the sand berm remains intact throughout the year, breaching only during particularly high tides or intense rain events. Therefore, the lagoon's connection to nearshore seawater is primarily via surface water - groundwater interaction through the sand berm. Because Younger Lagoon is largely isolated from a surface water connection with the ocean, runoff from upgradient urban and agricultural land has an enhanced impact on water (and presumably sediment) quality. As a result, the lagoon is eutrophic and experiences annual algal blooms. Groundwater surveys suggest surface water, groundwater, and coastal seawater are hydraulically connected at Younger Lagoon, and mixing among these water masses appears to influence water geochemistry. To date, no chemical analyses have been conducted on sediment from Younger Lagoon. To address this data gap we collected sediment samples during a February 2013 field campaign. One set of sediment samples is from the bottom of the lagoon along a transect perpendicular to the shoreline and another set is from an approximately 1 m depth profile on the lagoon side of the sand berm (depth of the groundwater table at the time of collection). These samples are being analyzed for HgT, MMHg, and total organic carbon (TOC) and will provide a first glimpse into the distribution of mercury species and organic carbon in sediments from the Younger Lagoon Reserve. We will also collect and analyze sediment samples from another lagoon site with comparable watershed characteristics.

Hohn, R. A.; Ganguli, P. M.; Swarzenski, P. W.; Richardson, C. M.; Merckling, J.; Johnson, C.; Flegal, A. R.

2013-12-01

274

Advanced Sediment Washing for Decontamination of New York/New Jersey Harbor Dredged Materials  

E-print Network

1 Advanced Sediment Washing for Decontamination of New York/New Jersey Harbor Dredged Materials of contaminated sediments dredged from our nations waterways. More than 400 million cubic yards (CY) of sediments are dredged annually from U.S. waterways, and each year, close to 60 million CY of this material is disposed

Brookhaven National Laboratory

275

AMS radiocarbon dating of organic fractions from varved lake sediments: an empirical test of reliability  

Microsoft Academic Search

Replicate cores of annually laminated (varved) sediments have been used to test the accuracy and precision of chronologies of lake sediment accumulation over the last 1000 years, based on AMS 14C measurements. The internally consistent results show that in the case of the soft-water lake sediments studied (Kassjön, northern Sweden), all the organic fractions that include aquatic components give significantly

Frank Oldfield; Peter R. J. Crooks; Douglas D. Harkness; Gunilla Petterson

1997-01-01

276

A late Holocene varved sediment record of environmental change from northern Ellesmere Island, Canada  

Microsoft Academic Search

A composite record of varve sedimentation is presented from high arctic meromictic Lake C2. The combination of a short runoff and sediment transport season with the strong density stratification of the lake lead to the formation of annual sediment couplets. This conclusion was confirmed by 210Pb determinations. High intra-lake correlation of the varves allowed the construction of a composite record

Scott F. Lamoureux; Raymond S. Bradley

1996-01-01

277

Challenges of ecosystem restoration in Louisiana - availability of sediment and its management  

NASA Astrophysics Data System (ADS)

Human intervention has impaired the Mississippi River's ability to deliver sediment to its delta wetlands, and as a consequence acute land loss in coastal Louisiana has resulted in an unprecedented ecocatastrophe. To mitigate this degradation, an unparalleled restoration effort is underway. For this effort to be successful and sustainable, various sediment input mechanisms must be integrated, including: building appropriate sediment-diversions; beneficially using the millions of cubic metres of sediment dredged annually from navigational channels; harvesting deposits of sand and suitable sediment from the river and offshore; and related sediment management activities that are compatible with other uses of the river. A comprehensive sediment management plan has been developed to identify and delineate potential sediment sources for restoration, and to provide a framework for managing sediment resources wisely, cost effectively, and in a systematic manner. The Louisiana Sediment Management Plan provides regional strategies for improved comprehensive management of Louisiana's limited sediment resources.

Khalil, S. M.; Freeman, A. M.

2015-03-01

278

Surface erosion, sediment transport, and reservoir sedimentation  

Microsoft Academic Search

Systematic plans and policies are needed to reduce adverse impacts of sedimentation and prolong the useful life of reservoirs. The ability to estimate the rate of watershed surface erosion, sediment transport, scour and deposition in a river system, and sediment deposition and distribution in a reservoir is essential to the development of sound sediment management plans and policies. The empirical

CHIH TED YANG; TIMOTHY J. RANDLE; SHIANG-KUEEN HSU

1998-01-01

279

A re-evaluation of sediment and solute transfers in Karkevagge Swedish Lapland  

NASA Astrophysics Data System (ADS)

Karkevagge, Swedish Lapland, has been the site of detailed geomorphic investigations for over sixty years. The classic study by Rapp (1960) not only identified the dominant processes operating on slope evolution in the valley, but also their magnitudes. Since that landmark study, there has been on-going research focused on better understanding magnitudes and frequencies of the dominant processes, but there has been no comprehensive reassessment of the overall sediment and solute fluxes in the valley. This paper compiles data from numerous recent studies in an effort to obtain an understanding of contemporary sediment fluxes in the valley. . Kärkevagge is a 5km long glacial valley located in northern Swedish Lapland at approximately 68o26' N latitude and 18o18'E longitude. The 30 year mean annual air temperature from the nearby Katterjakk climate station is -1.7oC and mean annual precipitation is 844mm. Some 50% of the precipitation comes in the form of snow. Mean total sediment output from the catchment is 0.2-11.2tkm-2d-1 (Rehn et al., 1982). There is however considerable spatial variability in sediment transfer within the valley. Solifluction accounts for the greatest sediment mass transfer in the valley at 1176 t/km2/yr. Mean mass transfer is in the vicinity of 20,000t/yr. (Ridefelt et al., 2009). Annual movement is on average 4cm/ yr. but displays considerable spatial variability depending on moisture availability Slush avalanches and slush torrents represent significant contributors to sediment transfer in the valley, with mean mass/area transfers of 128t/km2/yr. They display considerable variability in their magnitude, varying from as little as 0.5m3 to >300m3. Slush torrents may contribute between 10,000 and 20,000m3 of mass flow (Gude et al., 2000). Solute transfer amounts to 46t/km2/yr. for the valley as a whole but there is considerable spatial variability. Total solute flux is greatest at the valley outlet, but within the valley solute flux is greatest at the base of the dam impounding Lake Rissajaure. Within-valley solute variability is strongly controlled by bedrock lithology variability. Earth slides and debris flows account for approximately 43t/km2/yr. Rockfalls account for approximately 8.7 t/km2/yr. while small avalanches account for 1.4t/km2/yr. These mass movements display considerable spatial and temporal variability in magnitude and frequency within the valley. Valley side wash moves 0.59t/km2/yr. of fine sediment. Fluvial transport is estimated to be between 40-50 t/km2/yr. flood and slush events contribute suspended sediment up to as much as 3.4t/km2/day. There is considerable variability in suspended sediment transport within the valley channel systems (Rhen et al. 1982). Rapp's (1960) sediment transfer rates continue to provide a broadly reliable framework for understanding sediment fluxes in Kärkevagge. However subsequent calculations suggest some earlier magnitude determinations need minor revision. Process rates are highly variable spatially and temporally.

Dixon, John

2014-05-01

280

TOTAL M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total Spring 2010  

E-print Network

TOTAL M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total M F Total Spring 2010 Freshmen 400 4 4 8 31 13 44 63 13 76 34 2 36 27 5 32 27 2 29 106 8 34 3 37 0 1 1 X X BS Total 1943 57 236 363 119 180 192 603 42 134 17 MS Total 216 18 2 44 X 32 58 39

Hayes, Jane E.

281

Cladoceran remains in lake sediments: a comparison between plankton counts and sediment records  

Microsoft Academic Search

To evaluate the comparability of neo- and paleo-limnology, we made year-to-year as well as seasonal comparisons of contemporary\\u000a zooplankton data and cladoceran remains in thick (9–42 mm) annual laminations in sediment of Lake Vesijärvi, southern Finland.\\u000a We calculated the expected annual exuviae production of nine planktonic taxa in the water column using contemporary zooplankton\\u000a records, and compared the value to the

Mirva Nykänen; Kirsi Vakkilainen; Mikko Liukkonen; Timo Kairesalo

2009-01-01

282

Colorado River sediment transport 1. Natural sediment supply limitation and the influence of Glen Canyon Dam  

USGS Publications Warehouse

Analyses of flow, sediment-transport, bed-topographic, and sedimentologic data suggest that before the closure of Glen Canyon Dam in 1963, the Colorado River in Marble and Grand Canyons was annually supply-limited with respect to fine sediment (i.e., sand and finer material). Furthermore, these analyses suggest that the predam river in Glen Canyon was not supply-limited to the same degree and that the degree of annual supply limitation increased near the head of Marble Canyon. The predam Colorado River in Grand Canyon displays evidence of four effects of supply limitation: (1) seasonal hysteresis in sediment concentration, (2) seasonal hysteresis in sediment grain size coupled to the seasonal hysteresis in sediment concentration, (3) production of inversely graded flood deposits, and (4) development or modification of a lag between the time of a flood peak and the time of either maximum or minimum (depending on reach geometry) bed elevation. Analyses of sediment budgets provide additional support for the interpretation that the predam river was annually supply-limited with respect to fine sediment, but it was not supply-limited with respect to fine sediment during all seasons. In the average predam year, sand would accumulate and be stored in Marble Canyon and upper Grand Canyon for 9 months of the year (from July through March) when flows were dominantly below 200-300 m3/s; this stored sand was then eroded during April through June when flows were typically higher. After closure of Glen Canyon Dam, because of the large magnitudes of the uncertainties in the sediment budget, no season of substantial sand accumulation is evident. Because most flows in the postdam river exceed 200-300 m3/s, substantial sand accumulation in the postdam river is unlikely.

Topping, D.J.; Rubin, D.M.; Vierra, L.E., Jr.

2000-01-01

283

Fluvial sediments a summary of source, transportation, deposition, and measurement of sediment discharge  

USGS Publications Warehouse

This paper presents a broad but undetailed picture of fluvial sediments in streams, reservoirs, and lakes and includes a discussion of the processes involved in the movement of sediment by flowing water. Sediment is fragmental material that originates from the chemical or physical disintegration of rocks. The disintegration products may have many different shapes and may range in size from large boulders to colloidal particles. In general, they retain about the same mineral composition as the parent rocks. Rock fragments become fluvial sediment when they are entrained in a stream of water. The entrainment may occur as sheet erosion from land surfaces, particularly for the fine particles, or as channel erosion after the surface runoff has accumulated in streams. Fluvial sediments move in streams as bedload (particles moving within a few particle diameters of the streambed) or as suspended sediment in the turbulent flow. The discharge of bedload varies with several factors, which may include particle size and a type of effective shear on the surface of the streambed. The discharge of suspended sediment depends partly on concentration of moving sediment near the streambed and hence on discharge of bedload. However, the concentration of fine sediment near the streambed varies widely, even for equal flows, and, therefore, the discharge of fine sediment normally cannot be computed theoretically. The discharge of suspended sediment also depends on velocity, turbulence, depth of flow, and fall velocity of the particles. In general, the coarse sediment transported by a stream moves intermittently and is discharged at a rate that depends on properties of the flow and of the sediment. If an ample supply of coarse sediment is available at the surface of the streambed, the discharge of the coarse sediment, such as sand, can be roughly computed from properties of the available sediment and of the flow. On the other hand, much of the fine sediment in a stream usually moves nearly continuously at about the velocity of the flow, and even low flows can transport large amounts of fine sediment. Hence, the discharge of fine sediments, being largely dependent on the availability of fine sediment upstream rather than on the properties of the sediment and of the flow at a cross section, can seldom be computed from properties, other than concentrations based directly on samples, that can be observed at the cross section. Sediment particles continually change their positions in the flow; some fall to the streambed, and others are removed from the bed. Sediment deposits form locally or over large areas if the volume rate at which particles settle to the bed exceeds the volume rate at which particles are removed from the bed. In general, large particles are deposited more readily than small particles, whether the point of deposition is behind a rock, on a flood plain, within a stream channel, or at the entrance to a reservoir, a lake, or the ocean. Most samplers used for sediment observations collect a water-sediment mixture from the water surface to within a few tenths of a foot of the streambed. They thus sample most of the suspended sediment, especially if the flow is deep or if the sediment is mostly fine; but they exclude the bedload and some of the suspended sediment in a layer near the streambed where the suspended-sediment concentrations are highest. Measured sediment discharges are usually based on concentrations that are averages of several individual sediment samples for a cross section. If enough average concentrations for a cross section have been determined, the measured sediment discharge can be computed by interpolating sediment concentrations between sampling times. If only occasional samples were collected, an average relation between sediment discharge and flow can be used with a flow-duration curve to compute roughly the average or the total sediment discharges for any periods of time for which the flow-duration c

Colby, B.R.

1963-01-01

284

Hydroclimatic controls over sediment transport and clastic varve formation in the Canadian Arctic; ten years of process research (Invited)  

NASA Astrophysics Data System (ADS)

Clastic varved sedimentary records have been used as key paleoenvironmental records in regions where other high resolution proxy records are not available. These varved records are often interpreted as proxies of hydroclimatic processes: a combination of one or more climatic or meteorological processes that generate sufficient hydrological response to alter sediment delivery to the lake. While most clastic varved records have used statistical regression techniques to interpret the varve-climate relationship, few records have been investigated from a process perspective, and fewer still have sustained process studies for more than a two years. Although process studies are not an absolute requirement for interpreting clastic varve records, there remains a compelling rationale for pursuing them to enhance the interpretation of the hydroclimatic signals within the varves. Process research at the Cape Bounty Arctic Watershed Observatory (CBAWO) on south-central Melville Island (74°55'N, 109°35'W), Canada, are carried out in paired watersheds that drain into similar lakes that both contain long varve sequences. Parallel measurements have been undertaken to characterize climate, hydrology, sediment transport, limnology and sediment deposition processes. At CBAWO, stream flow is generated primarily from snow melt during the spring and it is during this period that the majority of sediment is often transported to lakes. The main control over water volume and maximum discharge rate is catchment snow water equivalence (SWE), most reliably measured as total runoff. While incoming radiation and air temperature correlate with daily discharge, there is no significant correlation between energy and discharge at the seasonal level. Annual sediment yields suggest a close correspondence between SWE, sediment yield and sediment deposition in traps in the lake bottom. In some years, rainfall plays an important role over sediment yield. In 2009, a single two-day event was responsible for more than 80% of the annual yield. By contrast, in 2012, a similar rainfall event generated essentially no runoff response. These results point to the key hydroclimatic processes that affect sediment accumulation and varve properties and can aid in calibration of the varve paleoenvironmental signal. Despite the relative hydroclimatic simplicity of this setting, the primary processes for sediment delivery are complex and can vary substantially in a given year.

Lamoureux, S. F.

2013-12-01

285

Sediment transport patterns and climate change: the downstream Tuul River case study, Northern Mongolia.  

NASA Astrophysics Data System (ADS)

Ongoing changes in the Central Asian climate including increasing temperatures can influence the hydrological regimes of rivers and the waterborne transport of sediments. Changes in the latter, especially in combination with adverse human activities, may severely impact water quality and aquatic ecosystems. However, waterborne transport of sediments is a result of complex processes and varies considerably between, and even within, river systems. There is therefore a need to increase our general knowledge about sediment transport under changing climate conditions. The Tuul River, the case site of this study, is located in the upper part of the basin of the Selenga River that is the main tributary to Lake Baikal, a UNESCO World Heritage Site. Like many other rivers located in the steppes of Northern Mongolia, the Tuul River is characterized by a hydrological regime that is not disturbed by engineered structures such as reservoirs and dams. However, the water quality of the downstream Tuul River is increasingly affected by adverse human activities - including placer gold mining. The largest contribution to the annual river discharge occurs during the relatively warm period in May to August. Typically, there are numerous rainfall events during this period that cause considerable river flow peaks. Parallel work has furthermore shown that due to climate change, the daily variability of discharge and numbers of peak flow events in the Tuul River Basin has increased during the past 60 years. This trend is expected to continue. We here aim at increasing our understanding of future sediment transport patterns in the Tuul River, specifically considering the scenario that peak flow events may become more frequent due to climate change. We use a one-dimensional sediment transport model of the downstream reach of the river to simulate natural patterns of sediment transport for a recent hydrological year. In general, the results show that sediment transport varies considerably spatially and temporally. Peak flow events during the warm period contribute largely to the total annual transport of sediments and also to the erosion of stored bed material. These results suggest that if the number of peak flow events will increase further due to climate change, there will be a significant increase in the annual sediment load and consequently in the load of contaminants that are attached to the sediments, in particular downstream of mining sites. The present results are furthermore consistent with parallel studies on sediment transport and climate change showing that increased water discharges and frequencies of rainfall/flow events can lead to enhanced erosion processes. Furthermore, in addition to climate change effects, human activates can change sediment loads in rivers to even greater extent, as pointed out in several studies. Thus, several different challenges can be expected to face the management of Central Asian rivers such as Tuul and their ecosystems in the future.

Pietro?, Jan; Jarsjö, Jerker

2014-05-01

286

Water and sediment transport modeling of a large temporary river basin in Greece.  

PubMed

The objective of this research was to study the spatial distribution of runoff and sediment transport in a large Mediterranean watershed (Evrotas River Basin) consisting of temporary flow tributaries and high mountain areas and springs by focusing on the collection and use of a variety of data to constrain the model parameters and characterize hydrologic and geophysical processes at various scales. Both monthly and daily discharge data (2004-2011) and monthly sediment concentration data (2010-2011) from an extended monitoring network of 8 sites were used to calibrate and validate the Soil and Water Assessment Tool (SWAT) model. In addition flow desiccation maps showing wet and dry aquatic states obtained during a dry year were used to calibrate the simulation of low flows. Annual measurements of sediment accumulation in two reaches were used to further calibrate the sediment simulation. Model simulation of hydrology and sediment transport was in good agreement with field observations as indicated by a variety of statistical measures used to evaluate the goodness of fit. A water balance was constructed using a 12 year long (2000-2011) simulation. The average precipitation of the basin for this period was estimated to be 903 mm yr(-1). The actual evapotranspiration was 46.9% (424 mm yr(-1)), and the total water yield was 13.4% (121 mm yr(-1)). The remaining 33.4% (302 mm yr(-1)) was the amount of water that was lost through the deep groundwater of Taygetos and Parnonas Mountains to areas outside the watershed and for drinking water demands (6.3%). The results suggest that the catchment has on average significant water surplus to cover drinking water and irrigation demands. However, the situation is different during the dry years, where the majority of the reaches (85% of the river network are perennial and temporary) completely dry up as a result of the limited rainfall and the substantial water abstraction for irrigation purposes. There is a large variability in the sediment yield within the catchment with the highest annual sediment yield (3.5 t ha(-1)yr(-1)) to be generated from the western part of the watershed. The developed methodology facilitated the simulation of hydrology and sediment transport of the catchment providing consistent results and suggesting its usefulness as a tool for temporary rivers management. PMID:25497675

Gamvroudis, C; Nikolaidis, N P; Tzoraki, O; Papadoulakis, V; Karalemas, N

2015-03-01

287

Estimating selenium removal by sedimentation from the Great Salt Lake, Utah  

USGS Publications Warehouse

The mass of Se deposited annually to sediment in the Great Salt Lake (GSL) was estimated to determine the significance of sedimentation as a permanent Se removal mechanism. Lake sediment cores were used to qualitatively delineate sedimentation regions (very high to very low), estimate mass accumulation rates (MARs) and determine sediment Se concentrations. Sedimentation regions were defined by comparison of isopach contours of Holocene sediment thicknesses to linear sedimentation rates determined via analysis of 210Pb, 226Ra, 7Be and 137Cs activity in 20 short cores (<5 cm), yielding quantifiable results in 13 cores. MARs were developed via analysis of the same radioisotopes in eight long cores (>10 cm). These MARs in the upper 1-2 cm of each long core ranged from 0.019 to 0.105 gsed/cm2/a. Surface sediment Se concentrations in the upper 1 or 2 cm of each long core ranged from 0.79 to 2.47 mg/kg. Representative MARs and Se concentrations were used to develop mean annual Se removal by sedimentation in the corresponding sedimentation region. The spatially integrated Se sedimentation rate was estimated to be 624 kg/a within a range of uncertainty between 285 and 960 kg/a. Comparison to annual Se loading and other potential removal processes suggests burial by sedimentation is not the primary removal process for Se from the GSL. ?? 2009 Elsevier Ltd.

Oliver, W.; Fuller, C.; Naftz, D.L.; Johnson, W.P.; Diaz, X.

2009-01-01

288

Mercury Methylation Rates in Prairie Wetland Sediments  

NASA Astrophysics Data System (ADS)

The majority of methylmercury (MeHg) in aquatic ecosystems is likely produced through methylation of Hg(II) by sulfate-reducing and iron-reducing bacteria. Wetland sediments may be significant sites of MeHg production, due to the combination of anoxic conditions and availability of organic matter to support microbial activity. Methylmercury produced by methylation of inorganic mercury within wetland sediments may be transferred to the water column, allowing for bioaccumulation of neurotoxic MeHg in the aquatic food web. Little information is available on sediment MeHg and total mercury concentrations, mercury methylation rates, and MeHg flux to the water column in prairie wetlands. Sediment cores from the St. Denis National Wildlife Area (SDNWA), ~40 km east of Saskatoon in central Saskatchewan, Canada, will be collected to measure sediment mercury methylation rates, total mercury, and MeHg concentrations in prairie wetland sediments. The SDNWA has been a site of prairie wetland research since 1968 and is located near the northern boundary of the Prairie Pothole Region which supports 50-80% of North American waterfowl. Sediment MeHg production will be measured in 2011 through the injection of 201Hg stable isotope to sediment cores from 12 prairie wetlands located within and nearby the SDNWA. Amended sediment cores will be incubated in situ for four hours to allow methylation of a fraction of the inorganic mercury stable isotope to Me201Hg. Analysis of the incubated sediment cores will allow for measurement of MeHg production rates, MeHg, and total mercury concentrations. Additional sediment cores will be taken to determine sediment water content, organic content, and porosity. Water samples from sediment pore water and the wetland water column will be analyzed for MeHg, total mercury, DOC, sulphate, SUVA, and water chemistry. Methylmercury flux from sediment pore water to the overlying water column will be calculated. Sediment MeHg production rates in the 12 wetlands will be compared to pore water data to identify factors associated with variation in MeHg production of prairie wetland sediments.

Hoggarth, C.; Hall, B.

2011-12-01

289

Estimation of local extreme suspended sediment concentrations in California Rivers  

E-print Network

climate where river discharge is driven by seasonal winter rainfall and prone to episodic sedimentEstimation of local extreme suspended sediment concentrations in California Rivers Yves Tramblaya Brunswick, Fredericton, N.B., Canada Abstract The total amount of suspended sediment load carried

Paris-Sud XI, Université de

290

Accumulation rates and sediment deposition in the northwestern Mediterranean  

Microsoft Academic Search

As part of the EROS 2000 programme, sediment mixing and accumulation rates in the northwestern Mediterranean Sea were determined, applying the 210Pb dating method to a total of 49 boxcores, and the results from 29 sediment cores are presented here. On the basis of the results from the 49 sediment cores, an attempt was made to present a general picture

Z. Zuo; D. Eisma; R. Gieles; J. Beks

1997-01-01

291

Concentrations and transport of suspended sediment, nutrients, and pesticides in the lower Mississippi-Atchafalaya River subbasin during the 2011 Mississippi River flood, April through July  

USGS Publications Warehouse

High streamflow associated with the April–July 2011 Mississippi River flood forced the simultaneous opening of the three major flood-control structures in the lower Mississippi-Atchafalaya River subbasin for the first time in history in order to manage the amount of water moving through the system. The U.S. Geological Survey (USGS) collected samples for analysis of field properties, suspended-sediment concentration, particle-size, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, and up to 136 pesticides at 11 water-quality stations and 2 flood-control structures in the lower Mississippi-Atchafalaya River subbasin from just above the confluence of the upper Mississippi and Ohio Rivers downstream from April through July 2011. Monthly fluxes of suspended sediment, suspended sand, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, atrazine, simazine, metolachlor, and acetochlor were estimated at 9 stations and 2 flood-control structures during the flood period. Although concentrations during the 2011 flood were within the range of what has been observed historically, concentrations decreased during peak streamflow on the lower Mississippi River. Prior to the 2011 flood, high concentrations of suspended sediment and nitrate were observed in March 2011 at stations downstream of the confluence of the upper Mississippi and Ohio Rivers, which probably resulted in a loss of available material for movement during the flood. In addition, the major contributor of streamflow to the lower Mississippi-Atchafalaya River subbasin during April and May was the Ohio River, whose water contained lower concentrations of suspended sediment, pesticides, and nutrients than water from the upper Mississippi River. Estimated fluxes for the 4-month flood period were still quite high and contributed approximately 50 percent of the estimated annual suspended sediment, nitrate, and total phosphorus fluxes in 2011; the largest fluxes were estimated at the water-quality station located at Vicksburg, Mississippi. The majority of the suspended-sediment flux introduce into the lower Mississippi-Atchafalaya River subbasin during the 2011 flood was in the form of fine-grained particles from the upper Mississippi River—77 percent of the suspended-sediment flux compared to 23 percent from the Ohio River. As water moved downstream along the lower Mississippi River, there were losses in suspended-sediment flux because of deposition and backwater areas. Fluxes showed a greater response to increased streamflow in the Atchafalaya River than in the lower Mississippi River. The result was a gain in suspended-sediment flux with distance downstream in the Atchafalaya River because of resuspension of previously deposited materials—particularly sand particles. Overall, 13 percent less suspended sediment left the lower Mississippi-Atchafalaya River subbasin than entered it from the confluence of the upper Mississippi and Ohio Rivers during the flood. The loss in suspended-sediment flux during the flood accounted for 14 percent of the 2011 annual suspended-sediment flux loss within the lower Mississippi-Atchafalaya River subbasin. Nitrate composed approximately 70 percent of the total nitrogen flux at all of the sampled water-quality stations, excluding the Arkansas River. Almost 2.4 times more nitrate flux entered the lower Mississippi-Atchafalaya River subbasin from the upper Mississippi River than from the Ohio River. As nitrate moved down the lower Mississippi River and the Atchafalaya River, there were no substantial losses or gains in flux, indicating that nitrate moved conservatively within the subbasin during the 2011 flood. Although streamflow was the largest on record, nitrate flux during the flood period resulted in a zone of hypoxia in the Gulf of Mexico that was only the tenth largest on record. The flux of total phosphorus in the lower Mississippi-Atchafalaya River subbasin during the 2011 flood was strongly related to suspended-sediment flux at most of the stations. There were significant gains in total phospho

Welch, Heather L.; Coupe, Richard H.; Aulenbach, Brent T.

2014-01-01

292

Identifying trends in sediment discharge from alterations in upstream land use  

USGS Publications Warehouse

Environmental monitoring is a primary reason for collecting sediment data. One emphasis of this monitoring is identification of trends in suspended sediment discharge. A stochastic equation was used to generate time series of annual suspended sediment discharges using statistics from gaging stations with drainage areas between 1606 and 1 805 230 km2. Annual sediment discharge was increased linearly to yield a given increase at the end of a fixed period and trend statistics were computed for each simulation series using Kendal's tau (at 0.05 significance level). A parameter was calculated from two factors that control trend detection time: (a) the magnitude of change in sediment discharge, and (b) the natural variability of sediment discharge. In this analysis the detection of a trend at most stations is well over 100 years for a 20% increase in sediment discharge. Further research is needed to assess the sensitivity of detecting trends at sediment stations.

Parker, R.S.; Osterkamp, W.R.

1995-01-01

293

Elwha River Restoration: Sediment Management  

NASA Astrophysics Data System (ADS)

The removal of Elwha and Glines Canyon Dams on the Elwha River relies on controlled reservoir drawdown increments and natural river flows to erode and redistribute the reservoir sediment, estimated to be a total of 23 (× 3) million m3. To mitigate for the predicted sediment effects, facilities have been constructed for water quality and flood protection. A sediment monitoring program is being implemented by an interdisciplinary team from Reclamation and National Park Service to integrate real-time measurements with continually updated numerical model predictions. The most recent numerical reservoir modeling and monitoring results indicate about 20 to 25 percent of the reservoir sediment has been released since the start of dam removal. Monitoring results in 2012 and early 2013 confirmed that controlled reservoir drawdown increments have induced sufficient vertical and lateral erosion of delta surfaces behind both dams. Predam channel and floodplain surface has been exposed in numerous portions of Lake Aldwell, with the release of coarse and fine sediment in the first few pools below Elwha Dam. The material released from Lake Aldwell has included organic material. With the removal of about three quarters of Glines Canyon Dam and the disappearance of Lake Mills, coarse bedload sediment has been continually released into the downstream river since late fall 2012. Field measurements and numerical modeling are being used to track the progression of the sediment wave downstream to the Elwha River mouth. Initial findings are that the aggradation was greatest immediately downstream of Glines Canyon Dam, and filled pools and transformed river planform from step-pool to glide for most of the 7 mile reach between Lake Mills and Lake Aldwell. Although there has not been a major flood, winter flows and spring snowmelt have significantly reworked the released sediment and remnants of the pre-sediment release pools and rapids have re-emerged. Large wood and organics have also been a consistent component of the released material. Future monitoring will include documenting the effect of encountering the lakebed muds on erosion rates of delta sediments in the former Lake Mills. Uncertainty in the amount of sediments released from Lake Mills will be addressed through continued monitoring as part of the adaptive management plan set forth during the restoration project. Monitoring will also continue to document the progression of sediments in the downstream Elwha River system.. NPS web camera photograph of Lake Mills delta upstream from Glines Canyon Dam.

Kimbrel, S.; Bountry, J.; Randle, T. J.; Ritchie, A.; Huginin, H.; Torrance, A.

2013-12-01

294

Turbidity-based sediment monitoring in northern Thailand: Hysteresis, variability, and uncertainty  

NASA Astrophysics Data System (ADS)

Annual total suspended solid (TSS) loads in the Mae Sa Catchment in northern Thailand, determined with an automated, turbidity-based monitoring approach, were approximately 62,000, 33,000, and 14,000 Mg during the three years of observation. These loads were equivalent to basin yields of 839 (603-1170), 445 (217-462), and 192 (108-222) Mg km-2 for the 74.16-km2 catchment during 2006, 2007, and 2008, respectively. The yearly uncertainty ranges indicate our loads may be underestimated by 38-43% or overestimated by 28-33%. In determining the annual loads, discharge (Q) and turbidity (T) values were compared against 333 hand-sampled total suspended solid concentrations (TSS) measured during 18 runoff events and other flow conditions across the three-year period. Annual rainfall varied from 1632 to 1934 mm; and catchment runoff coefficients (annual runoff/annual rainfall) ranged from 0.25 to 0.41. Measured TSS ranged from 8 to 15,900 mg l-1; the low value was associated with dry-season base flow; the latter, a wet-season storm. Storm size and location played an important role in producing clockwise, anticlockwise, and complex hysteresis in the Q-TSS relationship. Turbidity alone was a good estimator for turbidity ranges of roughly 10-2800 NTU (or concentrations approximately 25-4000 mg l-1). However, owing to hysteresis and high sediment concentrations that surpass the detection limits of the turbidity sensor during many annual storms, TSS was estimated best using a complex multiple regression equation based on high/low ranges of turbidity and Q as independent variables. Turbidity was not a good predictor of TSS fractions >2000 ?m. Hysteresis in the monthly Q-TSS relationship was generally clockwise over the course of the monsoon season, but infrequent large dry-season storms disrupted the pattern in some years. The large decrease in annual loads during the study was believed to be related to depletion of fine sediment delivered to the stream by several landslides occurring the year prior to the study. The study indicated the importance of monitoring Q and turbidity at fine resolutions (e.g., sub-hourly) to capture the TSS dynamics and to make accurate load estimations in this flashy headwater stream where hysteresis in the Q-TSS signature varied at several time scales.

Ziegler, Alan D.; Benner, Shawn G.; Tantasirin, Chatchai; Wood, Spencer H.; Sutherland, Ross A.; Sidle, Roy C.; Jachowski, Nicholas; Nullet, Mike A.; Xi, Lu Xi; Snidvongs, Anond; Giambelluca, Thomas W.; Fox, Jefferson M.

2014-11-01

295

Heavy metal pollution status in surface sediments of the coastal Bohai Bay.  

PubMed

Bohai Bay, the second largest bay of Bohai Sea, largely due to the huge amount of pollutants discharged into it annually and its geohydrologic condition, is considered to be one of the most polluted marine areas in China. To slow down, halt and finally reverse the environmental deterioration of Bohai Sea, some researchers have proposed to connect it with Jiaozhou Bay in the western coast of Southern Yellow Sea by digging an interbasin canal through Shandong Peninsula. In order to assess the heavy metal pollution and provide background information for such a large geoengineering scheme, surface sediments from 42 stations covering both riverine and marine regions of the northwestern coast of Bohai Bay were analyzed for heavy metal content and fractionation (Cd, Cr, Cu, Ni, Pb and Zn). Three empirically derived sediment quality guidelines were used to assess the pollution extent of these metals. The studied metals had low mobility except for Cd at all stations and Zn at some riverine stations. Although a high mobility of Cd was observed, it could hardly cause a bad effect on the environment owing to its low total concentrations. Anthropogenic influence on the accumulation of studied heavy metals in sediments of Bohai Bay was obvious, but their contents were relatively lower to date comparing with some other marine coastal areas that receive important anthropogenic inputs. Taking as a whole, surface sediments of northwestern Bohai Bay had a 21% probability of toxicity based on the mean effects range-median quotient. PMID:22285040

Gao, Xuelu; Chen, Chen-Tung Arthur

2012-04-15

296

Cumulative watershed effects (CWEs) result from the overlapping effects of management activities in time or space. The routing and downstream accumulation of sediment from  

E-print Network

data indicated that 13-95% of the variation in sediment transport rates could be explained by discharge activities in time or space. The routing and downstream accumulation of sediment from forest management range from the short-term variability of sediment transport rates to the variability in annual sediment

MacDonald, Lee

297

Event Driven Deltaic Sedimentation On A Low Gradient, Low Energy Shelf: The Sediment Dynamics Of The Brazos River Subaqueous Delta  

NASA Astrophysics Data System (ADS)

The Brazos River Delta, located along the Texas Coast in the Northwestern Gulf of Mexico, is located on a 130 km-wide, low gradient shelf, with a tidal range of 0.5 m and a mean wave height of 1.1 m. With the river supplying 10 - 16 Mt of sediment annually, this study investigated the fate of fluvial sediments within a 150 km2 area on the shelf proximal to the river mouth. Results from sediment cores indicate that significant accumulation is occurring only in the western third of the study area with long-term averaged accumulation rates near 2 cm/yr. This sediment is accumulating in distinct, centimeters thick event layers. Two-thirds of the study area shows little net accumulation. A time series of cores from this area shows that sediment is deposited following a major flood event. Less than 1 year later, the flood deposit has been completely remobilized and removed. Following a hurricane, the area experienced approximately 5 cm of erosion. Within the cores, the sediments exhibit a unique color spectrum. Sediment layer colors range from red, derived from the river, to grey, typical of marine sediments. Fluvial sediments are red in color when initially deposited, and remobilization of sediments and transport across the shelf can mix fluvial sediments with grey marine sediments. A sediment budget suggests that most of the sediment supplied by the river is not accumulating within this study area proximal to the river mouth. These results indicate that following deposition of fluvial sediments, waves and currents resuspend and transport most of the sediment both along and across the shelf beyond the study area. Accumulation occurs only in the area where fluvial deposits exhibit increased thickness and frequency to outpace remobilization. This study shows the importance of marine processes in modulating sedimentation within a low energy delta system.

Carlin, J. A.; Dellapenna, T. M.

2012-12-01

298

Seasonal and interannual changes of planktic foraminiferal fluxes in the Gulf of Lions (NW Mediterranean) and their implications for paleoceanographic studies: Two 12-year sediment trap records  

NASA Astrophysics Data System (ADS)

In order to investigate the seasonal and interannual variability of planktic foraminiferal fluxes in the NW Mediterranean, 266 samples from two 12-year-long sediment traps were analyzed. Two mooring lines were deployed at the east (Station Planier) and the west (Station Lacaze Duthiers) of the Gulf of Lions. The moorings were deployed at a water depth of around 1000 m and were equipped with sediment traps at 500 m above bottom (mab). In addition, an array of 13 core-tops recovered from different key areas of the Gulf of Lions is described. At Lacaze Duthiers, average foraminiferal fluxes were about double (411.8 shells m-2 d-1) those found at the Planier sampling site (225.4 shells m-2 d-1), probably due to the fertilizing effect of the Rhone river plume and the general oceanographic circulation. The annual total foraminiferal fluxes exhibited a unimodal trend, with maxima recorded during the winter-spring transition, i.e. the spring bloom, and minima during summer. Therefore, planktic foraminifers found in the sedimentary record in the Gulf of Lions may reflect the flux during the winter-spring period, rather than throughout the annual cycle. A total of eleven planktic foraminiferal species were identified in the sediment trap and core-top samples but only four species were dominant in the assemblages: Globigerina bulloides Neogloboquadrina pachyderma (dex.), Globorotalia inflata and Globorotalia truncatulinoides. The foraminiferal assemblages in the Gulf of Lions reflected the relatively cold conditions of the Northern Basin. No clear relationship between the NAO (North Atlantic Oscillation) and planktic foraminiferal fluxes was found in the sediment trap records. The low planktic foraminiferal fluxes recorded during the spring of 1998 were probably related to the anomalous environmental conditions triggered by the 1997-98 El Niño event. Furthermore, sediment trap samples were compared with surficial sediments recovered from different environmental and sedimentary settings of the Gulf of Lions and the application of these results in paleoceanographic reconstructions is discussed.

Rigual-Hernández, Andrés S.; Sierro, Francisco J.; Bárcena, María A.; Flores, José A.; Heussner, Serge

2012-08-01

299

Spatial Variations in Archaeal Lipids of Surface Water and Core-Top Sediments in the South China Sea and Their Implications for Paleoclimate Studies?†  

PubMed Central

The South China Sea (SCS) is the largest marginal sea of the western Pacific Ocean, yet little is known about archaeal distributions and TEX86-based temperatures in this unique oceanic setting. Here we report findings of abundances in both core lipids (CL) and intact polar lipids (IPL) of Archaea from surface water (CL only) and core-top sediments from different regions of the SCS. TEX86-derived temperatures were also calculated for these samples. The surface water had extremely low abundances of CL (average of 0.05 ± 0.13 ng/liter; n = 75), with higher values present in regions where upwelling is known to occur. The core-top sediments had CL values of 0.1 to 0.9 ?g/g, which are on the low end of CL concentrations reported for other marine sediments and may reflect the oligotrophic nature of the open SCS. The IPL of Archaea accounted for 6 to 36.4% of total lipids (CL plus IPL), indicating that the majority of archaeal lipids in core-top sediments were derived from nonliving cells. The TEX86-based temperatures of surface water were overall lower than satellite-based sea surface temperatures or CTD-measured in situ temperatures. The core-top sediment samples, however, had TEX86 temperatures very close to the mean annual sea surface temperatures, except for samples with water depths of less than 100 m. Our results demonstrated low and heterogeneous distributions of archaeal lipids in surface water and core-top sediments of the SCS, which may reflect local or regional differences in productivity of Archaea. While TEX86-based temperatures for core-top marine sediments at deep water depths (>100 m) generally reflected mean annual sea surface temperatures, TEX86 temperatures in surface water varied basin wide and underestimated sea surface temperatures in most locations for the season when surface water samples were collected. PMID:21890672

Wei, Yuli; Wang, Jinxiang; Liu, Jie; Dong, Liang; Li, Li; Wang, Hui; Wang, Peng; Zhao, Meixun; Zhang, Chuanlun L.

2011-01-01

300

Scale as a factor in designing sampling programs for determination of annual trace element fluxes  

USGS Publications Warehouse

Concentration data of suspended sediment-associated trace elements are a requisite for estimation of annual chemical fluxes. Fluvial suspended sediment and associated trace elements display marked shortterm spatial and temporal variability, suggesting that determination of annual fluxes requires high frequency depth and width integrated sampling and subsequent chemical analyses. When time scales are shifted from hours or days to a year, short-term variability is less important. A 2 year study on the Arkansas River indicates that it may be possible, after detailed site characterization of mean/median sediment chemical data, to estimate annual fluxes of trace elements solely through monitoring of discharge and suspended sediment concentration.

Horowitz, A.J.

1995-01-01

301

Modeling sediment in stormwater runoff from urban areas  

E-print Network

to estimate sediment in stormwater runoff for small urban watersheds. The model simulates the contribution of sediments from each of the different land surfaces present within an urban watershed. It was determined that different land surfaces contribute... sediments differently, and that a better estimate of the total sediment load could be determined by representing each of the major land surfaces independently. The model was developed and tested using four small urban watersheds in Austin and Houston...

Haster, Thomas Wayne

1991-01-01

302

Scanning micro-X-ray fluorescence elemental mapping: A new tool for the study of laminated sediment records  

Microsoft Academic Search

The utility of elemental mapping by scanning X-ray fluorescence (XRF) in the study of annual laminated sedimentary records was investigated on eight annually laminated sediment types. The examples were chosen to illustrate the potential of this approach in environments dominated by terrigenous, biological and chemical deposition. Individual laminae were identifiable in elemental maps of all sediment types and were enhanced

T. M. Shanahan; J. T. Overpeck; J. B. Hubeny; J. King; F. S. Hu; K. Hughen; G. Miller; J. Black

2008-01-01

303

Modelling stream sediment concentration: An assessment of enhanced rainfall and storm frequency  

NASA Astrophysics Data System (ADS)

SummaryRainfall patterns have a well recognised effect on erosion, sediment transport and water quality. In recent years, there has been a focus on understanding the impact of changing climate on rainfall and storm patterns both globally and in Australia with research directed to examine how the global hydrological cycle will respond to climate change. This study investigates the effect of different rainfall patterns on erosion and resultant water quality in a small study catchment in the Northern Territory, Australia. Rainfall projections for the study area indicate an increase in storm activity but there has been little assessment of this variability and its impact on resultant water quality. Numerical modelling studies are an essential means of assessing hydrological and geomorphological impacts of changing rainfall patterns resulting from climate variability. Here, a numerical model that simulates erosion, deposition and water quality (CAESAR) is used to assess several different rainfall scenarios over a 1000 year modelled period. The model results reveal that increased rainfall amount and intensity increases sediment transport rates but predicted annual sediment concentration (total load) was variable and non-linear but within predicted ranges for the catchment and region. In terms of impact of increased rainfall and storms on sediment output, the more frequent returns of high intensity rainfall increases sediment output but average concentration may reduce as a result of the increased discharge. Subtle thresholds may operate as a result of both external and internal forcings where differences in rainfall events and resultant sediment delivery produce rapid change in erosion rates and patterns producing autogenic adjustments within the catchment. The study provides a sensitivity analysis of both model parameterisation and differing rainfall scenarios on long-term water quality as well as a method for assessing the impact of rainfall variability on catchment scale hydrology.

R Hancock, G.

304

The Ribagorda sand gully (east-central Spain): Sediment yield and human-induced origin  

NASA Astrophysics Data System (ADS)

Gullies are developed under different climatic conditions and lithologies; however, those formed on sands have been scarcely described. This paper reports the study of the Ribagorda sand gully, 2.57 ha in area (east-central Spain). The main objectives were to characterize and quantify its geomorphic dynamics and to trace its origin. We described the landforms of the gully and measured the surface strength of the sand. We monitored, for six years, the filling of the storage areas of three check dams built downstream from the gully, and related it with rainfall characteristics. We also described the nature of the sediments trapped by the dams and estimated the amount of sediment eroded since the gully formation. Finally, we consulted historical records and maps to determine past land uses and transformations that may have affected the origin of the gully. The study shows a high diversity of landforms, denoting active processes, consistent with a measured mean annual sediment yield of 114 Mg ha- 1 yr- 1. A statistically significant relationship exists between the mass of sediment (Mg) and: 1) the total rainfall (mm) (P = 0.0007) or 2) the analysed rainfall intensities. Among five identified facies in the sedimentary wedge, the sandy ones are predominant. The total amount of sediment eroded by the Ribagorda gully since its origin was 962,800 Mg. The results are unequivocal signs of an intense geomorphic activity within the gully, with an alluvial-fan type deposition in the dams. We interpret that the Ribagorda gully was initiated by deforestation after the 13th century, when forests began to be intensively logged, and before the 18th century, when the gully was first indirectly described in print. The age, origin, evolution and dynamics of this gully indicate that this landscape is currently evolving towards a new steady state, after human disturbances over centuries. Given the gully evolution and local extent, we suggest that no correction measures are needed for its management.

Martín-Moreno, C.; Fidalgo Hijano, C.; Martín Duque, J. F.; González Martín, J. A.; Zapico Alonso, I.; Laronne, J. B.

2014-11-01

305

A spatially referenced regression model (SPARROW) for suspended sediment in streams of the Conterminous U.S.  

USGS Publications Warehouse

Suspended sediment has long been recognized as an important contaminant affecting water resources. Besides its direct role in determining water clarity, bridge scour and reservoir storage, sediment serves as a vehicle for the transport of many binding contaminants, including nutrients, trace metals, semi-volatile organic compounds, a nd numerous pesticides (U.S. Environmental Protection Agency, 2000a). Recent efforts to addr ess water-quality concerns through the Total Maximum Daily Load (TMDL) process have iden tified sediment as the single most prevalent cause of impairment in the Nation’s streams a nd rivers (U.S. Environmental Protection Agency, 2000b). Moreover, sediment has been identified as a medium for the tran sport and sequestration of organic carbon, playing a potentia lly important role in understa nding sources and sinks in the global carbon budget (Stallard, 1998). A comprehensive understanding of sediment fate a nd transport is considered essential to the design and implementation of effective plans for sediment management (Osterkamp and others, 1998, U.S. General Accounting Office, 1990). An exte nsive literature addr essing the problem of quantifying sediment transport has produced a nu mber of methods for estimating its flux (see Cohn, 1995, and Robertson and Roerish, 1999, for us eful surveys). The accuracy of these methods is compromised by uncertainty in the concentration measurements and by the highly episodic nature of sediment movement, particul arly when the methods are applied to smaller basins. However, for annual or decadal flux es timates, the methods are generally reliable if calibrated with extended periods of data (Robertson and Roerish, 1999). A substantial literature also supports the Universal Soil Loss Equation (U SLE) (Soil Conservation Service, 1983), an engineering method for estimating sheet and rill erosion, although the empirical credentials of the USLE have recently been questioned (Tri mble and Crosson, 2000). Conversely, relatively little direct evidence is available concerning the fate of sediment. The common practice of quantifying sediment fate with a sediment deliv ery ratio, estimated from a simple empirical relation with upstream basin area, does not artic ulate the relative importance of individual storage sites within a basin (Wolman, 1977). Rates of sediment deposition in reservoirs and flood plains can be determined from empirical measurement s , but only a limited number of sites have been monitored, and net rates of deposition or loss from other potential sinks and sources is largely unknown (Stallard, 1998). In particular, little is known about how much sediment loss from fields ultimately makes its way to stream channels, and how much sediment is subsequently stored in or lost from th e streambed (Meade and Parker, 1985, Trimble and Crosson, 2000). This paper reports on recent progress made to a ddress empirically the question of sediment fate and transport on a national scale. The model pres ented here is based on the SPAtially Referenced Regression On Watershed attr ibutes (SPARROW) methodology, fi rst used to estimate the distribution of nutrients in str eams and rivers of the United Stat es, and subsequently shown to describe land and stream processes affecting the delivery of nutrients (Smith and others, 1997, Alexander and others, 2000, Preston and Brakeb ill, 1999). The model makes use of numerous spatial datasets, available at the national level, to explain long-term sediment water-quality conditions in major streams and rivers throughou t the United States. Sediment sources are identified using sediment erosion rates from the National Resources I nventory (NRI) (Natural Resources Conservation Service, 2000) and apportioned over the landscape according to 30- meter resolution land-use information from th e National Land Cover Data set (NLCD) (U.S. Geological Survey, 2000a). More than 76,000 reservoirs from the National Inventory of Dams (NID) (U.S. Army Corps of Engin eers, 1996) are identified as pot ential sediment sinks. Other, non-anthropogenic sou

Schwarz, Gregory E.; Smith, Richard A.; Alexander, Richard B.; Gray, John R.

2001-01-01

306

As was hypothesized, annual ET water losses appears to be driven by seasonal variations in the total aboveground biomass of the treatment wetland. We found that only air temperature and PAR were significant climatic drivers of ET. However, unlike  

E-print Network

shore-to-open-water transects were distributed proportionally across a treatment flow cell based.T.A. 2003. Water and mass budgets of a vertical=-flow constructed wetland used for wastewater treatment· As was hypothesized, annual ET water losses appears to be driven by seasonal variations

Hall, Sharon J.

307

The role of channel and floodplain storage in the suspended sediment budget of the River Ouse, Yorkshire, UK  

NASA Astrophysics Data System (ADS)

This study attempts to quantify the amount of fine-grained (ca. < 150 ?m) sediment stored on the floodplains and on the channel bed of the non-tidal sections of the main channels in the catchment of the River Ouse (3315 km 2) and of one of its tributaries, the River Waarfe (818 km 2), in Yorkshire, UK. Caesium-137 analyses of floodplain sediment cores were used to quantify the amount of Iloodplain deposition as a result of overbank flooding during the last ca. 40 years. A combination of bulk and sectioned cores were collected along transects perpendicular to the channel at 26 sites throughout the study basins. In general, rates of overbank sedimentation decrease with distance from the channel. The average values for individual transects range between 0.010 and 0.554 g cm -2 year -1. Floodplain storage along the main channels of the Ouse and Wharfe basins accounts for 60645 and 10325 t year -1, respectively, and represents a net loss from the system. The amount of fine-grained sediment stored on the channel bed was estimated by a survey undertaken in August 1996, during which the fine material deposited on the bed was resuspended and its mass estimated at 16 locations. The average values for the individual locations range between 0.017 and 0.924 g cm -2 and tend to increase downstream. The total channel bed storage at the time of sampling in 1996 was estimated to be 16076 and 1866 t for the Ouse and Wharfe basins, respectively. It is assumed that channel bed storage is seasonal and that no net loss to the system occurs at the annual timescale. Floodplain storage for the Ouse and Wharfe basins represents 39 and 49%, and channel bed storage equals 10 and 9%, respectively, of the annual suspended sediment load (1995-1996) delivered to the channel system. These results have important implications for the routing of fine-grained sediment and sediment-associated contaminants in drainage basins, and for the interpretation of downstream sediment yields in terms of upstream sediment mobilisation.

Walling, Desmond E.; Owens, Philip N.; Leeks, Graham J. L.

1998-04-01

308

Nutrient retention in plant biomass and sediments from the salt marsh in Hangzhou Bay estuary, China.  

PubMed

Nutrient load into the ocean can be retained during the process of plant uptake and sedimentation in marshes along the bay zone. Seasonal variations of biomass and nutrient concentration in three dominated plant assemblages and associated sediments were monitored in this study area to determine effects of salt marsh on nutrient retention. Results showed that plant aboveground biomass displayed a unimodal curve with nutrient concentration generally decreased from spring to winter. Belowground biomass was relatively low during the rapid growth period with nutrient concentration tending to decrease and then increase during this period. Plant total nitrogen (TN) pools are higher than total phosphorus (TP) pools, and both pools showed significant seasonal variations. Water purification coefficients (WPC) of nutrients by plant assimilation were 34.4/17.3, 19.3/24.0, and 5.14/6.04 t/(m(2) year) (TN/TP) for Phragmites australis, Spartina alterniflora, and Scirpus mariqueter, respectively. Overall, these results suggest that higher annual plant biomass and nutrient assimilation contribute to greater nutrient retention capacity and accumulation in sediments, thereby enabling reduced eutrophication in transitional waters. PMID:23589271

Shao, Xuexin; Wu, Ming; Gu, Binhe; Chen, Yinxu; Liang, Xinqiang

2013-09-01

309

Development of a reference artificial sediment for chemical testing adapted to the MELA sediment contact assay.  

PubMed

Most persistent organic pollutants, due to their hydrophobic properties, accumulate in aquatic sediments and represent a high risk for sediment quality. To assess the toxicity of hydrophobic pollutants, a novel approach was recently proposed as an alternative to replace, refine and reduce animal experimentation: the medaka embryo-larval sediment contact assay (MELAc). This assay is performed with Japanese medaka embryos incubated on a natural sediment spiked with the compound being tested. With the aim of improving this assay, our study developed a reference exposure protocol with an artificial sediment specifically designed to limit natural sediment composition uncertainties and preparation variability. The optimum composition of the new artificial sediment was tested using a model polycyclic aromatic hydrocarbon (PAH), fluoranthene. The sediment was then validated with two other model PAHs, benz[a]anthracene and benzo[a]pyrene. Various developmental end points were recorded, including survival, embryonic heartbeat, hatching delay, hatching success, larval biometry and abnormalities. The final artificial sediment composition was set at 2.5 % dry weight (dw) Sphagnum peat, 5 % dw kaolin clay and 92.5 % dw silica of 0.2- to 0.5-mm grain size. In contrast with natural sediments, the chemical components of this artificial matrix are fully defined and readily identifiable. It is totally safe for fish embryos and presents relatively high sorption capacities for hydrophobic compounds. Studies with other hydrophobic and metallic contaminants and mixtures should be performed to further validate this artificial sediment. PMID:24526399

Le Bihanic, Florane; Perrichon, Prescilla; Landi, Laure; Clérandeau, Christelle; Le Menach, Karyn; Budzinski, Hélène; Cousin, Xavier; Cachot, Jérôme

2014-12-01

310

Surface sediment analysis and modern sedimentation rates in Flandres Bay, Western Antarctic Peninsula  

NASA Astrophysics Data System (ADS)

Flandres Bay is located on the west side of the Antarctic Peninsula, where temperatures have risen more than the global average over the last century and where many glaciers have shown signs of retreat in recent decades. The Antarctic Ice Cap drains through tidewater glaciers that flow into bays around the peninsula. In this study, multibeam swath bathymetry data, seismic profiles, and sediment cores were used to determine the distribution of surface sediment types and modern sedimentation rates and compare these to the sediment accumulation down core. The bathymetry of the fjord includes small basins with flat bottoms, highly irregular seamounts, and deep channels in the bedrock as well as subglacial geomorphic features carved by the flow of glaciers. Results of sediment analysis show a variation in sediment type throughout the bay from pebbles with minor matrix close to the glacial calving margin to muddy diatomaceous ooze in the outer bay. Sediment accumulation rates were measured using 137 Cs counts on bulk sediment and 14 C on carbonate, usually forams, found after sieving bulk sediment. Samples for 137 Cs were taken on the top few centimeters of sediment cores and show a higher rate of sediment accumulation compared to rates calculated using 14 C, which measures millennial scale accumulation rates to the base of the core. Density logs of the sediment cores have relatively consistent values, indicating that the change in calculated accumulation rates is not simply due to compaction. As predicted, accumulation rates are higher close to the glaciers, where there is a high occurrence of ice rafted debris and dropstones; the sedimentation rates decrease away from the source and sediment analysis shows an increase in the biogenic component in the sediment, especially diatoms, in the outer bay. Other fjords adjacent to Flandres Bay, including Beascochea to the south, show similar trends of increasing rates of sediment accumulation in the upper portions of cores. In a simple model, sediment accumulation rate at any one location would decrease as the ice margin retreats, leaving the sample location more and more distal from the sediment source. However, as our results show increasing sediment accumulation during modern day ice-margin retreat in Flandres Bay, we interpret this to indicate increased sediment yield across the basin with ice is in a retreat phase, possibly undergoing faster flow, yielding a greater total volume of sediment.

Munoz, Y. P.; Wellner, J. S.; Mead, K. A.

2012-12-01

311

Efficiency of erosion mitigation strategies in reducing sediment-loading rates from unpaved road networks into coral reef-bearing waters of the Eastern Caribbean  

NASA Astrophysics Data System (ADS)

Erosion from unpaved road networks represents a critical source of stress affecting the coral reef systems of the U.S. Virgin Islands in the Northeastern Caribbean. Combined community- and government-driven efforts to reduce sediment contributions from unpaved roads in the island of St. John have consisted in improving road drainage design, paving selected road segments, and constructing sediment retention structures. Here we describe empirical evidence attesting to the efficacy of these mitigation efforts. Road drainage improvements reduced sediment production rates to about a third of pre-treatment levels. Road-segment scale erosion rates following paving ranged from 5-30% of pre-treatment levels, depending on road slope and road grading frequency. A 616-m3 sediment retention pond proved to contain 86 Mg of sediment annually and about 94% of the runoff generated from a 12 ha sub-catchment with an unpaved road density of 19 km km-2. Watershed-scale modeling evaluations suggested that the combination of these three treatments within the 13-km2 Coral Bay watershed resulted in the reduction of annual sediment delivery rates from 445 Mg yr-1 to 327 Mg yr-1. Cost-effectiveness analyses suggest that road drainage improvements and construction of the detention pond provided the greatest reductions in sediment delivery per total amount of funds spent. Even though paving is a proven erosion control method, the high costs involved made it a relatively cost-inefficient method. Marine sedimentation of terrigenous sediment (land-derived) was regularly monitored (every 26 days) at 15 near-shore and reef sites from 2008 to 2013 below the treated and undeveloped watersheds. Sediment composition (% terrigenous) determined by loss on ignition was multiplied by the total sediment accumulation rate in tube sediment traps to obtain terrigenous sediment accumulation rates (in mg cm-2 d-1). Mean terrigenous sediment accumulation rates were over 24 (near-shore) and 6 (reef) times greater below developed compared to undeveloped watersheds. Comparisons of marine terrigenous accumulation rates between undeveloped and developed areas were consistent with those based on modeled sediment yields. At all near-shore sites below mitigated watersheds, mean post-mitigation marine terrigenous sediment accumulation rates were reduced by up to 70% of mean pre-mitigation values. Nevertheless, further analysis is required to evaluate whether the observed post-mitigation reduction is strictly related to watershed restoration. At the developed coral reef sites, acute terrigenous sediment accumulation rates during major storms equaled or exceeded coral-stressing levels (>50 mg cm-2d-1). Results from this research are being employed in the design of mitigation strategies within our study areas as well as in other parts of the Caribbean where roads are considered a major threat to coral reefs.

Ramos-Scharron, Carlos; Gray, Sarah; Sears, Whitney

2014-05-01

312

A field study on phytoremediation of dredged sediment contaminated by heavy metals and nutrients: the impacts of sediment aeration.  

PubMed

Compared to traditional chemical or physical treatments, phytoremediation has proved to be a cost-effective and environmentally sound alternative for remediation of contaminated dredged sediment. A field study was conducted in a sediment disposal site predominantly colonized by Typha angustifolia under different sediment moisture conditions to estimate the phytoremediation effects of dredged sediment. The moisture content was 37.30 % and 48.27 % in aerated and waterlogged sediment, respectively. Total nitrogen (TN) content was higher in the waterlogged sediment than in the aerated sediment. The total Cd contents were lower in aerated sediment, which was mainly resulted from the lower exchangeable fraction of Cd. The bioaccumulation of P, Cu and Pb in T. angustifolia was promoted by waterlogging, and the belowground tissue concentrations and accumulation factors (AFs) of Cu were higher than that of other metals, which can be explained by that Cu is an essential micronutrient for plants. Consistent with many previous studies, T. angustifolia showed higher metal levels in roots than in above-ground tissues at both the sediment conditions. Due to the improved biomass produced in the aerated sediment, the removals of nutrients and the metals by plant harvest were higher from aerated sediment than from waterlogged sediment. It was indicated that maintaining the dredged sediment aerated can avoid release risk and plant uptake of metals, while the opposite management option can promote phytoextraction of these contaminants. PMID:25012206

Wu, Juan; Yang, Lihua; Zhong, Fei; Cheng, Shuiping

2014-12-01

313

Notes on sedimentation activities calendar year 1989  

USGS Publications Warehouse

This report is a digest of information furnished by Federal agencies conducting sedimentation investigations. The decision to publish the report was made in 1946, from a proposal by the Chairman of the Federal Interagency River Basin Committee, Subcommittee on Ground Water. The subcommittee approved the proposal and agreed to issue this report as a means of effecting better coordination of the work of various Federal agencies in the field of sedimentation. The report was issued on a quarterly basis in 1946 and 1947, from 1948 to 1953 reports were issued every 6 months, and from 1954 to the present, the report has been issued annually.

U.S. Interagency Advisory Committee on Water Data- Subcommittee on Sedimentation

1990-01-01

314

Notes on sedimentation activities calendar year 1988  

USGS Publications Warehouse

This report is a digest of information furnished by Federal agencies conducting sedimentation investigations. The decision to publish the report was made in 1946, from a proposal by the Chairman of the Federal Interagency River Basin Committee, Subcommittee on Ground Water. The subcommittee approved the proposal and agreed to issue this report as a means of effecting better coordination of the work of various Federal agencies in the field of sedimentation. The report was issued on a quarterly basis in 1946 and 1947, from 1948 to 1953 reports were issued every 6 months, and from 1954 to the present, the report has been issued annually.

U.S. Interagency Advisory Committee on Water Data- Subcommittee on Sedimentation

1989-01-01

315

Notes on sedimentation activities calendar year 1985  

USGS Publications Warehouse

This report is a digest of information furnished by Federal agencies conducting sedimentation investigations. The decision to publish the report was made in 1946, from a proposal by the Chairman of the Federal Interagercy River Basin Committee, Subcommittee on Ground Water. The subcommittee approved the proposal and agreed to issue this report as a means of effecting better coordination of the work of various Federal agencies in the field of sedimentation. From 1946 to 1947, the report was issued on a quarterly basis; from 1948 to 1953, reports were issued every 6 months; and from 1954 to the present, the report has been issued annually.

U.S. Interagency Advisory Committee on Water Data- Subcommittee on Sedimentation

1986-01-01

316

Notes on sedimentation activities calendar year 1984  

USGS Publications Warehouse

This report is a digest of information furnished by Federal agencies conducting sedimentation investigations. The decision to publish the report was made in 1946, from a proposal by the Chairman of the Federal Interagency River Basin Committee, Subcommittee on Ground Water. The Subcommittee approved the proposal and agreed to issue this report as a means of effecting better coordination of the work of various Federal agencies in the field of sedimentation. From 1946 to 1947 the report was issued on a quarterly basis, from 1948 to 1953 reports were issued every 6 months, and from 1954 to the present the report has been issued annually.

U.S. Interagency Advisory Committee on Water Data- Subcommittee on Sedimentation

1985-01-01

317

Notes on sedimentation activities calendar year 1987  

USGS Publications Warehouse

This report is a digest of information furnished by Federal agencies conducting sedimentation investigations. The decision to publish the report was made in 1946, from a proposal by the Chairman of the Federal Interagency River Basin Committee, Subcommittee on Ground Water. The subcommittee approved the proposal and agreed to issue this report as a means of effecting better coordination of the work of various Federal agencies in the field of sedimentation. The report was issued on a quarterly basis in 1946 and 1947, from 1948 to 1953 reports were issued every 6 months, and from 1954 to the present, the report has been issued annually.

U.S. Interagency Advisory Committee on Water Data- Subcommittee on Sedimentation

1988-01-01

318

Sediment quality in Rivers and their estuaries of an olive oil production area, Messinia, Greece.  

NASA Astrophysics Data System (ADS)

Sediment analysis at four major rivers (Pamisos, Aris, Velikas and Nedon) and their estuaries towards heavy metals took place in the Prefecture of Messinia, Greece, during two sampling campaigns in 2008 and 2011. The main industrial activity in the region is the operation of 250 olive oil industries and the main problem concerning pollution derives from the vast quantities of olive mill waste waters that are being generated annually most of which is currently discharged in nearby streams. Chemical parameters such as phenols, total organic carbon and certain heavy metals were found to be strongly correlated with the wastes from the olive oil industries. Major and minor elements (heavy metals) were measured in riverine and estuarine sediments. In parallel heavy metals were determined in the olive waste from a local industry, using atomic absorption spectrometry, in order to correlate the results with the sediment analysis. Major and Minor elements were recorded based upon the total percentage of the sediment samples and in order to eliminate the grain size effect, the concentrations were normalized towards Al. A pollution indice, the sediment enrichment factor, was also calculated, the high values of which towards Cr are of particular interest. Additionally organic carbon and total phenolic compounds were determined in rivers and their estuaries. High concentrations of Chromium were recorded in River Aris sediment, which seems to be the most polluted. Relatively high concentrations of zinc were encountered at rivers Aris and Pamisos while the chromium load seems to be higher near the estuaries of the rivers. The olive mill waste water analysis confirmed the existence of chromium in the waste and extremely elevated values were also found at a nearby station where these wastes tend to accumulate for decades. In contrast the results from the Nedon River indicated that it is not affected, since the low values found remained constant from the source of the river until its outfall in the Messinian Gulf. A significant enrichment in phenolic content of sediments as well in organic carbon was observed in 2011 when compared to 2008, in most of the cases, indicating degradation of the study aquatic ecosystems of Messinia Prefecture.

Anastasopoulou, Evaggelia; Pavlidou, Alexandra; Skoulikidis, Nikos; Dassenakis, Manos; Hatzianestis, Ioannis

2014-05-01

319

Sediment dynamics in the Mekong basin- a multi-objective calibration on discharge and sediment load  

NASA Astrophysics Data System (ADS)

The Mekong delta is one of the most extensively used deltas world wide and provides natural resources to more than 17 million people. Environmental issues in the Mekong delta are closely linked to water usage and availability. In addition, the sediment input to the floodplains during the annual flood plays a crucial role in terms of nutrient supply to agriculture. Since flood magnitudes and sediment delivery are driven by human activities and hydrological processes along the entire Mekong river, it is highly important to assess the dynamics upstream of the Mekong delta. This study applies the hydrological model SWIM to the watershed upstream of Kratie/Cambodia with a size of approximately 650.000 km2 and gives a quantitative depiction on the sediment and discharge dynamics. The model is driven by different, mostly globally available data sources. After the identification of the sensitive parameters, a multi objective calibration, namely the NSGA-II algorithm, is applied. The model simulates the discharge values well, e.g. by capturing the annual flood season and sediment dynamics. The next steps comprise an assessment of different sources of uncertainty that are incorporated in the model. This includes the climate input data and the sparsely available and highly variable sediment data. Eventually, the study shall provide a basis to examine the future developments along the Mekong river, for example, quantifying the impacts of potential reservoirs on the flow regime and sediment dynamics.

Luedtke, Stefan; Apel, Heiko; Viet Dung, Nguyen; Merz, Bruno

2013-04-01

320

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

PubMed

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 a high water level in the reservoir and is likely to result in acceptable water quality in the fjord. However, during periods of low drawdown, sediment pollution may again become a problem. PMID:11258827

Bogen, J; Bønsnes, T E

2001-02-01

321

Radiolarian assemblages from Santa Barbara Basin sediments: Recent interdecadal variability  

NASA Astrophysics Data System (ADS)

Santa Barbara Basin contains a sedimentary record ideal for high-resolution paleoclimate studies because of the annual varves and regional- to global-scale climate signals preserved in the sediments [Lange et al., 1990; Kennett and Ingram, 1995], even though it does not lie directly in the path of the California Current. A nearly 100-year annual time series (1909-1991) of polycystine radiolarian assemblages from Santa Barbara Basin (SBB) sediments was analyzed to the species level. Counts on a replicate SBB core, dated 1870-1987, indicate that results are reproducible and the flux of a few representative species can be extrapolated to estimate fluxes of environmentally sensitive groups. The frequency of species occurrences resembles a lognormal curve and year-by-year comparisons of species fluxes revealed only modest changes in the assemblages from 1909-1991, indicating that the assemblages represent a single oceanic province. For paleoceanographic analysis of the radiolarian record, species were combined into groups according to the water mass in which they occur. To test this method, temperature-sensitive species were identified using t- tests. This generated warm and cool classes exhibiting trends in relative flux similar to those of the water mass groups. Both total flux and relative fluxes of water mass groups relate to low-frequency, decadal-scale temperature fluctuations, but not strongly to El Niño-Southern Oscillation events. Generally, fluxes of species from different water masses covary suggesting changing carrying capacities and productivity through time, while the consistent inverse relationship in relative fluxes indicate variability in climate. The subtle, decadal-scale changes in assemblages, diversity, and increase in percent warm water fauna are consistent with a spin-down of the California Current System suggested by other records.

Weinheimer, A. L.; Cayan, D. R.

1997-10-01

322

Proxies of pre-industrial charcoal production and land use in lake sediments from South Brandenburg, Germany  

NASA Astrophysics Data System (ADS)

During the last decades, archaeological research has revealed that large-scale charcoal burning was carried out in Lower Lusatia (South Brandenburg) situated within the North Germany Lowland. From the 17th to the 19th century, charcoal was mainly produced for the ironwork in Peitz. Within the framework of the ICLEA project lake sediments from two lakes, Byhleguhrer See and Großsee, are investigated to study the impact of pre-industrial charcoal production on the environment. The investigation area is situated c. 15 km ne of Cottbus in the Tauerscher Forst, an area mainly forested with pine. The climate is continental (mean annual air temperature: 8-9 °C, mean annual precipitation sum: 565 mm). The geology and geomorphology were formed by Quaternary glaciations. Two lakes, Großsee and Byhleguhrer See, were selected for our research. Großsee (51° 56,007' N, 14° 28,282' E, 63 m a.s.l., max. 9 m water depth) is c. 0.31 km2 large and lies in the central part of the Tauersche Forst. Byhleguhrer See (51° 55,41' N, 14° 9,922' E, 50 m a.s.l., max. 1 m water depth) is situated in c. 22 km linear distance W of Großsee at the western margin of the Tauersche Forst. This lake is c. 0.89 km2 large. During the last 50 years Byhleguhrer See and its surrounding was intensively used (fishing, wastewater discharge, agriculture). Three short sediment cores were gained from each lake. All cores were opened, described and photographed. Magnetic susceptibility (split-core logger) and total element contents (µXRF) were measured on selected cores. Based on the first data, two sediment cores were chosen for further analyses (CNS, 14C-dating, etc.). The sediment core from Großsee (GR13-SH-PO56) is 77 cm long. The sediments are quite homogenous and have a high organic content. S values are increased in the upper part (10-30 cm sediment depth) correlating with high magnetic susceptibility and iron values, which hint on the occurrence of pyrite in the sediment. 14C-dating of the sediment base (71-75 cm sediment depth) resulted in an age of 778-1018 AD (2?, Poz-58091). The sediment core from Byhleguhrer See (BHG-13-1) is 107 cm long. Again, the sediments are homogenous and are rich in organics. CNS analyses are in progress. In the upper part high Fe and S contents (µXRF) correlate with high magn. susceptibility values hinting on pyrite. The base of the core (100-107 cm sediment depth) was 14C-dated to 1739-1531 BC (2?, Poz-58092) and 2872-2471 BC (2?, Poz-58093). Preliminary tests of charcoal particle contents of both sediment cores were carried out. In conclusion, the sediments of Großsee and Byhleguhrer See are quite homogenous. An anthropogenic disturbance of the uppermost sediment part cannot be excluded. But, the 14C-datings resulted in reasonable ages, even though we cannot rule out a hardwater effect on the radiocarbon ages of Byhleguhrer See. Most probably, the cores contain the relevant time span (17th - 19th century), when charcoal was produced in the surroundings. Besides the CNS analyses and absolute age determinations, at present the focus lies on microscopic charcoal analyses.

Raab, Alexandra; Frantiuc, Alexandru; Brademann, Brian; Ott, Florian; Hirsch, Florian; Brauer, Achim; Raab, Thomas

2014-05-01

323

In situ acoustic and laboratory ultrasonic sound speed and attenuation measured in heterogeneous soft seabed sediments: Eel River shelf, California  

Microsoft Academic Search

We compared in situ and laboratory velocity and attenuation values measured in seafloor sediments from the shallow water delta of the Eel River, California. This region receives a substantial volume of fluvial sediment that is discharged annually onto the shelf. Additionally, a high input of fluvial sediments during storms generates flood deposits that are characterized by thin beds of variable

Thomas J. Gorgas; Roy H. Wilkens; Shung S. Fu; L. Neil Frazer; Mike D. Richardson; Kevin B. Briggs; Homa Lee

2002-01-01

324

Little Ice Age recorded in summer temperature reconstruction from varved sediments of Donard Lake, Baffin Island, Canada  

Microsoft Academic Search

Clastic varved sediments from Donard Lake, in the Cape Dyer region of Baffin Island, provide a 1250 yr record of decadal-to-centennial scale climate variability. Donard Lake experiences strong seasonal fluctuations in runoff and sediment fluxes due to the summer melting of the Caribou Glacier, which presently dominates its catchment. The seasonal variation in sediment supply results in the annual deposition

J. J. Moore; K. A. Hughen; G. H. Miller

2001-01-01

325

12 CFR Appendix A to Part 707 - Annual Percentage Yield Calculation  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 false Annual Percentage Yield Calculation A Appendix A to Part 707 Banks... Appendix A to Part 707—Annual Percentage Yield Calculation The annual percentage yield (APY) measures the total amount of...

2014-01-01

326

12 CFR Appendix A to Part 707 - Annual Percentage Yield Calculation  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 false Annual Percentage Yield Calculation A Appendix A to Part 707 Banks... Appendix A to Part 707—Annual Percentage Yield Calculation The annual percentage yield (APY) measures the total amount of...

2012-01-01

327

12 CFR Appendix A to Part 1030 - Annual Percentage Yield Calculation  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 false Annual Percentage Yield Calculation A Appendix A to Part 1030 Banks... Appendix A to Part 1030—Annual Percentage Yield Calculation The annual percentage yield measures the total amount of interest...

2014-01-01

328

12 CFR Appendix A to Part 230 - Annual Percentage Yield Calculation  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 false Annual Percentage Yield Calculation A Appendix A to Part 230 Banks... Appendix A to Part 230—Annual Percentage Yield Calculation The annual percentage yield measures the total amount of interest...

2014-01-01

329

12 CFR Appendix A to Part 1030 - Annual Percentage Yield Calculation  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 false Annual Percentage Yield Calculation A Appendix A to Part 1030 Banks... Appendix A to Part 1030—Annual Percentage Yield Calculation The annual percentage yield measures the total amount of interest...

2012-01-01

330

12 CFR Appendix A to Part 230 - Annual Percentage Yield Calculation  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 false Annual Percentage Yield Calculation A Appendix A to Part 230 Banks... Appendix A to Part 230—Annual Percentage Yield Calculation The annual percentage yield measures the total amount of interest...

2012-01-01

331

12 CFR Appendix A to Part 230 - Annual Percentage Yield Calculation  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 false Annual Percentage Yield Calculation A Appendix A to Part 230 Banks... Appendix A to Part 230—Annual Percentage Yield Calculation The annual percentage yield measures the total amount of interest...

2011-01-01

332

12 CFR Appendix A to Part 1030 - Annual Percentage Yield Calculation  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Annual Percentage Yield Calculation A Appendix A to Part 1030 Banks... Appendix A to Part 1030—Annual Percentage Yield Calculation The annual percentage yield measures the total amount of interest...

2013-01-01

333

12 CFR Appendix A to Part 230 - Annual Percentage Yield Calculation  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Annual Percentage Yield Calculation A Appendix A to Part 230 Banks... Appendix A to Part 230—Annual Percentage Yield Calculation The annual percentage yield measures the total amount of interest...

2013-01-01

334

12 CFR Appendix A to Part 707 - Annual Percentage Yield Calculation  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Annual Percentage Yield Calculation A Appendix A to Part 707 Banks... Appendix A to Part 707—Annual Percentage Yield Calculation The annual percentage yield (APY) measures the total amount of...

2013-01-01

335

12 CFR Appendix A to Part 707 - Annual Percentage Yield Calculation  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 false Annual Percentage Yield Calculation A Appendix A to Part 707 Banks... Appendix A to Part 707—Annual Percentage Yield Calculation The annual percentage yield (APY) measures the total amount of...

2011-01-01

336

Annual maximum 5-day rainfall total and maximum number of consecutive dry days over Central America and the Caribbean in the late twenty-first century projected by an atmospheric general circulation model with three different horizontal resolutions  

NASA Astrophysics Data System (ADS)

We simulated changes in annual maximum 5-day rainfall (RX5D) and annual maximum number of consecutive dry days (CDD) in Central America, Mexico, and the Caribbean with three different horizontal resolution atmospheric global general circulation models (AGCMs) and quantified the uncertainty of the projections. The RX5Ds and CDDs were projected to increase in most areas in response to global warming. However, consistent changes were confined to small areas: for RX5D, both coastal zones of northern Mexico and the Yucatan Peninsula; for CDD, the Pacific coastal zone of Mexico, the Yucatan Peninsula, and Guatemala. All three AGCMs projected that RX5Ds and CDDs averaged over only the land area and over the entire area (land and ocean) would increase. The dependence of RX5D probability density functions on the horizontal resolutions was complex. Precipitation unrelated to tropical cyclones was primarily responsible for the projected increases in the frequency of RX5Ds greater than 300 mm.

Nakaegawa, T.; Kitoh, A.; Murakami, H.; Kusunoki, S.

2014-04-01

337

Total Phosphorus Loads for Selected Tributaries to Sebago Lake, Maine  

USGS Publications Warehouse

The streamflow and water-quality datacollection networks of the Portland Water District (PWD) and the U.S. Geological Survey (USGS) as of February 2000 were analyzed in terms of their applicability for estimating total phosphorus loads for selected tributaries to Sebago Lake in southern Maine. The long-term unit-area mean annual flows for the Songo River and for small, ungaged tributaries are similar to the long-term unit-area mean annual flows for the Crooked River and other gaged tributaries to Sebago Lake, based on a regression equation that estimates mean annual streamflows in Maine. Unit-area peak streamflows of Sebago Lake tributaries can be quite different, based on a regression equation that estimates peak streamflows for Maine. Crooked River had a statistically significant positive relation (Kendall's Tau test, p=0.0004) between streamflow and total phosphorus concentration. Panther Run had a statistically significant negative relation (p=0.0015). Significant positive relations may indicate contributions from nonpoint sources or sediment resuspension, whereas significant negative relations may indicate dilution of point sources. Total phosphorus concentrations were significantly larger in the Crooked River than in the Songo River (Wilcoxon rank-sum test, p<0.0001). Evidence was insufficient, however, to indicate that phosphorus concentrations from medium-sized drainage basins, at a significance level of 0.05, were different from each other or that concentrations in small-sized drainage basins were different from each other (Kruskal-Wallis test, p= 0.0980, 0.1265). All large- and medium-sized drainage basins were sampled for total phosphorus approximately monthly. Although not all small drainage basins were sampled, they may be well represented by the small drainage basins that were sampled. If the tributaries gaged by PWD had adequate streamflow data, the current PWD tributary monitoring program would probably produce total phosphorus loading data that would represent all gaged and ungaged tributaries to Sebago Lake. Outside the PWD tributary-monitoring program, the largest ungaged tributary to Sebago Lake contains 1.5 percent of the area draining to the lake. In the absence of unique point or nonpoint sources of phosphorus, ungaged tributaries are unlikely to have total phosphorus concentrations that differ significantly from those in the small tributaries that have concentration data. The regression method, also known as the rating-curve method, was used to estimate the annual total phosphorus load for Crooked River, Northwest River, and Rich Mill Pond Outlet for water years 1996-98. The MOVE.1 method was used to estimate daily streamflows for the regression method at Northwest River and Rich Mill Pond Outlet, where streamflows were not continuously monitored. An averaging method also was used to compute annual loads at the three sites. The difference between the regression estimate and the averaging estimate for each of the three tributaries was consistent with what was expected from previous studies.

Hodgkins, Glenn A.

2001-01-01

338

The sediment budget of a highly dynamic mesoscale catchment: The River Isábena  

NASA Astrophysics Data System (ADS)

The paper presents the sediment budget of the Isábena basin, a highly dynamic 445-km 2 catchment located in the Central Pyrenees that is patched by highly erodible areas (i.e., badlands). The budget for the period 2007-2009 is constructed following a methodology that allows the interpolation of intermittent measurements of suspended sediment concentrations and enables a subsequent calculation of sediment loads. Data allow specification of the contribution of each subbasin to the water and sediment yield in the catchment outlet. Mean annual sediment load was 235,000 t y - 1 . Specific sediment yield reached 2000 t km - 2 y - 1 , a value that indicates very high sedimentary activity, especially in the case of Villacarli and Lascuarre subcatchments, were most badlands are located. The specific sediment yield obtained for the entire Isábena is 527 t km - 2 y - 1 , a high value for such a mesoscale basin. Results show that a small part of the area (i.e., 1%) controls most of the catchment's gross sediment contribution. Sediment delivery ratio (ratio between sediment input from primary sources and basin export) has been estimated at around 90%, while in-channel storage represents the 5% of the annual load on average. The high connectivity between sediment sources (i.e., badlands) and transfer paths (i.e., streamcourses) exacerbates the influence of the local sediment production on the catchment's sediment yield, a quite unusual fact for a basin of this scale.

López-Tarazón, J. A.; Batalla, R. J.; Vericat, D.; Francke, T.

2012-02-01

339

Long-term trends in catchment export and lake retention of dissolved organic carbon, dissolved organic nitrogen, total iron, and total phosphorus: The Dorset, Ontario, study, 1978-1998  

NASA Astrophysics Data System (ADS)

Annual catchment export of total phosphorus (TP), dissolved organic carbon (DOC), total iron (Fe), and dissolved organic nitrogen (DON) to seven lakes in central Ontario was measured between 1978 and 1998. Fluctuations in annual water discharge and total DOC load (including precipitation) to the lakes over the 20-year period were similar in the seven study lakes. DOC export to the lakes responded proportionally to changes in discharge, decreasing during drier and warmer years. There were similar but less accentuated variations in annual DOC lake concentrations. There were no clear regional trends evident during the 20-year period toward drier or wetter conditions, less DOC load, clearer lakes, etc., that could be interpreted as signaling a shift toward a different equilibrium state. The fraction of the DOC load retained by lakes (transferred to sediments and the atmosphere) increased during an extended dry period. Fe, TP, and DON export decreased more than DOC export during the extended dry period. Runoff appears to affect Fe, TP, and DON export first by controlling export of organic matter and second by affecting water table position and thus redox levels in the surface layer of peatlands. Permanently drier conditions with less runoff would likely lead to clearer lakes that are less productive. Conversely, increased runoff would lead to more colored and productive lakes. Both scenarios have implications for subsistence and sport fishing economies.

Dillon, Peter J.; Molot, Lewis A.

2005-09-01

340

Calibration of an estuarine sediment transport model to sediment fluxes as an intermediate step for simulation of geomorphic evolution  

USGS Publications Warehouse

Modeling geomorphic evolution in estuaries is necessary to model the fate of legacy contaminants in the bed sediment and the effect of climate change, watershed alterations, sea level rise, construction projects, and restoration efforts. Coupled hydrodynamic and sediment transport models used for this purpose typically are calibrated to water level, currents, and/or suspended-sediment concentrations. However, small errors in these tidal-timescale models can accumulate to cause major errors in geomorphic evolution, which may not be obvious. Here we present an intermediate step towards simulating decadal-timescale geomorphic change: calibration to estimated sediment fluxes (mass/time) at two cross-sections within an estuary. Accurate representation of sediment fluxes gives confidence in representation of sediment supply to and from the estuary during those periods. Several years of sediment flux data are available for the landward and seaward boundaries of Suisun Bay, California, the landward-most embayment of San Francisco Bay. Sediment flux observations suggest that episodic freshwater flows export sediment from Suisun Bay, while gravitational circulation during the dry season imports sediment from seaward sources. The Regional Oceanic Modeling System (ROMS), a three-dimensional coupled hydrodynamic/sediment transport model, was adapted for Suisun Bay, for the purposes of hindcasting 19th and 20th century bathymetric change, and simulating geomorphic response to sea level rise and climatic variability in the 21st century. The sediment transport parameters were calibrated using the sediment flux data from 1997 (a relatively wet year) and 2004 (a relatively dry year). The remaining years of data (1998, 2002, 2003) were used for validation. The model represents the inter-annual and annual sediment flux variability, while net sediment import/export is accurately modeled for three of the five years. The use of sediment flux data for calibrating an estuarine geomorphic model guarantees that modeled geomorphic evolution will not exceed the actual supply of sediment from the watershed and seaward sources during the calibration period. Decadal trends in sediment supply (and therefore fluxes) can accumulate to alter decadal geomorphic change. Therefore, simulations of future geomorphic evolution are bolstered by this intermediate calibration step.

Ganju, N.K.; Schoellhamer, D.H.

2009-01-01

341

Tracing the origin of suspended sediment in a large Mediterranean river by combining continuous river monitoring and measurement of artificial and natural radionuclides.  

PubMed

Delivery of suspended sediment from large rivers to marine environments has important environmental impacts on coastal zones. In France, the Rhone River (catchment area of 98,000 km(2)) is by far the main supplier of sediment to the Mediterranean Sea and its annual solid discharge is largely controlled by flood events. This study investigates the relevance of alternative and original fingerprinting techniques based on the relative abundances of a series of radionuclides measured routinely at the Rhone River outlet to quantify the relative contribution of sediment supplied by the main tributaries during floods. Floods were classified according to the relative contribution of the main subcatchments (i.e., Oceanic, Cevenol, extensive Mediterranean and generalised). Between 2000 and 2012, 221 samples of suspended sediment were collected at the outlet and were shown to be representative of all flood types that occurred during the last decade. Three geogenic radionuclides (i.e., (238)U, (232)Th and (40)K) were used as fingerprints in a multivariate mixing model in order to estimate the relative contribution of the main subcatchment sources-characterised by different lithologies-in sediment samples collected at the outlet. Results showed that total sediment supply originating from Pre-Alpine, Upstream, and Cevenol sources amounted to 10, 7 and 2.10(6)tons, respectively. These results highlight the role of Pre-Alpine tributaries as the main sediment supplier (53%) to the Rhone River during floods. Other fingerprinting approaches based on artificial radionuclide activity ratios (i.e., (137)Cs/(239+240)Pu and (238)Pu/(239+240)Pu) were tested and provided a way to quantify sediment remobilisation or the relative contributions of the southern tributaries. In the future, fingerprinting methods based on natural radionuclides should be further applied to catchments with heterogeneous lithologies. Methods based on artificial radionuclides should be further applied to catchments characterised by heterogeneous post-Chernobyl (137)Cs deposition or by specific releases of radioactive effluents. PMID:25255199

Zebracki, Mathilde; Eyrolle-Boyer, Frédérique; Evrard, Olivier; Claval, David; Mourier, Brice; Gairoard, Stéphanie; Cagnat, Xavier; Antonelli, Christelle

2015-01-01

342

Light Weight Aggregates made from Dredged Harbour Sediments  

Microsoft Academic Search

Goal  Annually, 400.000 m3 harbour sediments are dredged to maintain the water depth in the harbours of Bremen and Bremerhaven. The sediment contains\\u000a organic and inorganic pollutants and hence is deposited on a landfill. Because of the limited capacity of that landfill alternative\\u000a treatment techniques are investigated. This study aims to evaluate the production of Light Weight Aggregates (LWA) from harbour

Kay Hamer; Astrid Hadeler; Thomas Muschalla; Jürgen Schröter; Giinter Timmer

2003-01-01

343

Sediment fingerprinting in Northern Jordan - approaching sediment comparability  

NASA Astrophysics Data System (ADS)

Jordan has a quantitative and qualitative water problem in combination with a growing demand by population increase. Around 65% of the freshwater used in Jordan is reported to originate from surface waters and reservoirs. Sediment loads harm the quality of these water bodies and fill up dams. A sediment fingerprint pilot study was implemented in an exemplary catchment in the NW of Jordan to investigate the possibility of geochemical differentiation between 6 sediment sources and calculate their relative contribution to the sink, the Wadi Al-Arab reservoir. The sediment fingerprint method relies on the comparability of sediment properties of the sources and the sink. However, selection processes during transport, preferential adsorption of elements on fine particles, and differences in inorganic carbonate content prevent a direct comparison. In previous studies this has been solved through selective sampling and analyzing certain grain size fractions or the mathematical derivation of correction factors. As no pre-knowledge existed in the Wadi Al-Arab catchment, selective grain size sampling would have implied the risk of neglecting important information already during the sampling process. Hence, a method was established that includes several steps to identify influential parameters (IPs), eliminate their impact and take account of their interrelations. It is based on a stepwise multiple regression analysis model (SMRAM) and generates element specific correction factors that take account for possible interdependencies between influential parameters as clay percentage and total organic and inorganic carbonates. In the further selection process of suitable elements for the fingerprint, we complemented the common used methods by a solubility analysis. Therefore, water profiles were physicochemical investigated in the dam lake. Differences in the chemical milieus during transport and sedimentation that affect the conservativeness of the chosen elements could be detected and taken account for. The study showed that common fingerprint elements and practices would have led to misinterpretations in the Wadi Al-Arab catchment and calls for a sound knowledge on catchment characteristics before the implementation of such a method.

Kraushaar, Sabine; Schumann, Thomas; Ollesch, Gregor; Siebert, Christian; Vogel, Hans-Joerg

2014-05-01

344

Elwha River Restoration: Sediment Management  

NASA Astrophysics Data System (ADS)

The 1 to 2-year removal of Elwha and Glines Canyon Dams on the Elwha River relies on controlled reservoir drawdown increments and natural river flows to erode and redistribute the reservoir sediment, estimated to be a total of 18 million m3. To mitigate for the predicted sediment effects, facilities have been constructed for water quality and flood protection, including water treatment plants, new wells, a new surface water intake, raising the height of existing levees, and the construction of new levees. A sediment monitoring program is being implemented by an interdisciplinary team from Reclamation and National Park Service to integrate real-time measurements with continually updated numerical model predictions. The most recent numerical reservoir modeling and monitoring results indicate about 50 percent of the reservoir sediment will remain in the reservoir while another 50 percent is predicted to be released downstream during dam removal and a few high flood periods following the completion of dam removal. Early monitoring results confirm that lowering the reservoir pool in a controlled increment, and then holding the reservoir pool at constant elevation, is inducing sufficient vertical and lateral erosion of the exposed delta surface. Predam channel and floodplain surface has been exposed in numerous portions of Lake Aldwell. The first major coarse sediment released from Lake Aldwell occurred in mid-April. This sediment release along with continued erosion during spring snowmelt of 2012 has resulted in deposition of the first few river pools below Elwha Dam. Deposition on riffles, where velocities are higher, has not occurred. Therefore, no major change to flood stage is predicted from the initial sediment release. The material released from Lake Aldwell has included organic material. About half of Glines Canyon Dam has been removal and Lake Mills is about one-quarter of its original size. Future monitoring will focus on continued tracking of the lateral erosion and progression of the delta front in Lake Mills, and the upcoming release of the coarse sediment from Lake Mills once the delta reaches the dam. The first wave of coarse bedload sediment is expected to be released in late fall of 2012.NPS web camera photograph of the Lake Mills delta upstream from Glines Canyon Dam.

Randle, T. J.; Bountry, J.; Ritchie, A.; Hugunin, H.; Torrence, A.

2012-12-01

345

Modeling the Effects of Climate Change on Water, Sediment, and Nutrient Discharge from the Maumee River Watershed  

NASA Astrophysics Data System (ADS)

A hydrologic model of the Maumee River watershed in NW Ohio, USA was constructed to test the effects of climate change on water flow and sediment and nutrient loading within the drainage basin. The Maumee River drains a larger area (17,100 km2) than any other watershed in the Great Lakes region before discharging into the Western Basin (WB) of Lake Erie. Approximately 70% of the land within the watershed is agricultural, resulting in excess sediment and nutrient loading in the WB. High nutrient concentrations, especially phosphate concentrations, contribute to harmful algal blooms (HABs) in Lake Erie, which is the source of drinking water for approximately 11 million people. After a decrease in Lake Erie HABs in the late 1980s and early 1990s, toxic cyanobacteria blooms have been prevalent in the WB every summer since 1995. To determine the effects of climate change on streamflow and sediment and nutrient loading in the Maumee River watershed, a Soil and Water Assessment Tool (SWAT) hydrologic model was constructed. Flow and suspended sediment calibrations were performed for 1995-1999 using observed data from four USGS gauging stations. Suspended sediment concentration, which correlates highly with total phosphorus concentration, was used as a proxy for total phosphorus loads. Downscaled climate projections from the World Climate Research Programme's (WCRP's) Coupled Model Intercomparison Project phase 3 (CMIP3) were inputted into the model to test the effects of climate change on the flow and suspended sediment discharge of the Maumee River. Validation was performed by inputting downscaled climate data for 1975-1999 and comparing the output to observed flow and suspended sediment data from the USGS gauging station at Waterville, Ohio. Model outputs for A1B, A2, and B1 climate scenarios indicate an overall decrease in annual flow over the next century, with higher flow in the winter and spring and lower total flow in the summer. However, model outputs also indicate large runoff events will become more frequent in the summer months, providing significant nutrient loads when conditions for HABs are most prevalent. Downscaled climate projections were also used to predict future changes in the magnitude and timing of suspended sediment loads in the Maumee River watershed. Large pulses of nutrients during summer months could fuel large HABs, decreasing the water quality of the WB of Lake Erie.

Cousino, L. K.; Becker, R.; Zmijewski, K. A.

2013-12-01

346

Assessment the spatial and temporary variability of sediments production taken into account the land use and the climate change, In the Paute river basin southern Ecuador  

NASA Astrophysics Data System (ADS)

Erosion processes and sediment production data for The Paute river basin watershed (5000 km2) located the south of Ecuador, are analyzed, its importance is in the hydroelectric sector in which the project generates 1200 Mw and that correspond approximately to 55% of the energy for the Ecuador. The anthropogenic intervention, the watershed geomorphologic characteristics, added to the great variability of present land use and to the non-uniform space and temporary distribution of the hydrologic events; contribute to the permanence of the erosive processes of formation of gullies, progressive degradation of land cover that is translated in a constant production of sediments. According to the load of suspended sediment monitoring campaign, values like 90% of the total production would occur during the rainy time and in very little number of variable intensities events, from this data, between 40% to 50% show values up to 25 mm h-1. Therefore it has been taken as an important criterion the Rain fall regime and the annual sediment production. Considering the later results, a scheme for projection of rates of erosion and sediment production has been settled down taken into account factors as: Regime and annual Rainfall average; Land cover type and its surface, and Space zoning of vulnerable areas. According to the degraded areas assessment and considering the current rainfall conditions regime and its land cover, and the available evidence with respect to the influence of the presence or absence of a good forest cover on rainfall it was settled down rates of erosion for the regional projection four main zones with the following ranks of annual erosion: i) natural zones < 5 t ha-1 a-1, II) zones of anthropogenic intervention from 5 to 50 t ha-1 a-1, III) zones of moderate erosion from 50 to 100 t has-1 a-1, and IV) high rates erosion zones > 100 t ha-1 a-1. Starting on 2010 is operating Mazar reservoir in the retention of sediments as support to Amaluza reservoir and therefore beneficial to increase the useful life of the dam that at the present time. The aim of the present paper is to establish if the impact of the processes of erosion and sedimentation in the Paute river basin would have direct consequences in the hydroelectric production and useful life of the dams; a scenario analysis of erosion processes with respect to main works of water retention for hydroelectrically production of the zone was done, the temporary scale of the analysis of sediments has been considered from year 2010 to year 2030; Using ECHAM A2 and the ECHAM B2 climate change scenarios.

Cisneros, F.; Pacheco, E.; Coello, C.; Wyseure, G.

2012-04-01

347

Estimating long-term sediment export using a seasonal rainfall-dependent hydrological model in the Glonn River basin, Germany  

NASA Astrophysics Data System (ADS)

In European catchments, rainfall and overland flow trigger erosive processes that could result in soil detachment and transportation. However, estimation of both erosive rainfalls and sediment yields is very challenging, especially in historical times when only precipitations at seasonal or annual scales are available. This motivated us to develop a parsimonious hydroclimatological model (ASCLIM, Annual Sediment CLImatological Model) for predicting catchment scale sediment yield when temporal and spatial high-resolution precipitation data are not available. The model was developed by using the annual data of suspended-sediment yield from Glonn basin (1981-1995, gauge of Hohenkammer, Germany) and seasonal rainfall data from a NOAA data set. The correlation coefficient between predicted and observed sediment yields was 0.94 and the efficiency index was 0.89. Once parameterized, the model was able to capture annual sediment yield variability better than the Langbein-Schumm and the Fournier Index equations, also based on limited sets of inputs. The model holds potential for historical reconstruction of sediment yields in the Glonn catchment (assuming constant land cover) and for simulating sediment fluxes from catchments with similar characteristics. Our application highlights the control of rainfall seasonality on sediment export and demonstrates that our sediment yield proxy could be considered as a good tool for the expectation and planning of soil conservation. Moreover, considering that we used modeled data to reconstruct past sediment loss, we could expect that using projected future rainfall data our proxy could be able to assess future scenarios.

Diodato, Nazzareno; de Vente, Joris; Bellocchi, Gianni; Guerriero, Luigi; Soriano, Marcella; Fiorillo, Francesco; Revellino, Paola; Guadagno, Francesco M.

2015-01-01

348

Co-occurrence correlations of heavy metals in sediments revealed using network analysis.  

PubMed

In this study, the correlation-based study was used to identify the co-occurrence correlations among metals in marine sediment of Hong Kong, based on the long-term (from 1991 to 2011) temporal and spatial monitoring data. 14 stations out of the total 45 marine sediment monitoring stations were selected from three representative areas, including Deep Bay, Victoria Harbour and Mirs Bay. Firstly, Spearman's rank correlation-based network analysis was conducted as the first step to identify the co-occurrence correlations of metals from raw metadata, and then for further analysis using the normalized metadata. The correlations patterns obtained by network were consistent with those obtained by the other statistic normalization methods, including annual ratios, R-squared coefficient and Pearson correlation coefficient. Both Deep Bay and Victoria Harbour have been polluted by heavy metals, especially for Pb and Cu, which showed strong co-occurrence with other heavy metals (e.g. Cr, Ni, Zn and etc.) and little correlations with the reference parameters (Fe or Al). For Mirs Bay, which has better marine sediment quality compared with Deep Bay and Victoria Harbour, the co-occurrence patterns revealed by network analysis indicated that the metals in sediment dominantly followed the natural geography process. Besides the wide applications in biology, sociology and informatics, it is the first time to apply network analysis in the researches of environment pollutions. This study demonstrated its powerful application for revealing the co-occurrence correlations among heavy metals in marine sediments, which could be further applied for other pollutants in various environment systems. PMID:24559934

Liu, Lili; Wang, Zhiping; Ju, Feng; Zhang, Tong

2015-01-01

349

Spatial and Temporal Connections Between Sediment Delivery and Resuspension Potential along the California Coast  

NASA Astrophysics Data System (ADS)

During storm events, the fluvial processes that discharge sediment and the oceanographic processes influencing dispersal of that sediment should be much more strongly coupled for small coastal watersheds than large watersheds. If this coupling of fine-grained sediment delivery and dispersal is significant, different dispersal rates and processes may be expected on the shelves off small rivers than would occur off large river systems. We have examined the oceanic forcings present on the shelf during flood events (the period during and immediately following peak discharge events) on rivers draining small coastal watersheds of California. Hydrologic data from the river mouth USGS gauge and oceanographic data from a nearby NDBC buoy were compared for the Eel, Salinas and Santa Ana Rivers. Although there are geographic differences between the systems, strong coupling is observed between river discharge, wind stresses and direction and wave size and period for all sites. Because waves likely influence the dispersal of recently delivered near-bed sediment, we also evaluated wave-induced shear stresses during river discharge events. Although there is elevated potential for resuspension (wave-induced shear stresses greater than the critical shear-stresses needed to resuspend silts and clays), of fine-grained material during and following these discharge events, the events do not fully account for the annual resuspension potential. For example, during and in the 48 hours following large discharge events from the Santa Clara River, wave-induced bottom shear stresses surpass the critical threshold more than 50 percent of the time. While this is important, it only accounts for 2/3 of the total period when wave-induced resuspension was possible in our record. The remaining times occurred during storm events that did not produce discharge events from the river, indicating that there is also great potential for sediment remobilization all along the California shelf during times without large new inputs from the rivers.

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

2006-12-01

350

Global Overview On Delivery Of Sediment To The Coast From Tropical River Basins  

NASA Astrophysics Data System (ADS)

Depending on definition, the tropics occupy between 16% and 19% of the earth's land surface, and discharge ~18.5% of the earth's fluvial water runoff. These flow regimes are driven by three types of sub-regional climate: rainforest, monsoon, and savannah. Even though the tropics include extreme precipitation events, particularly for the SE Asian islands, the general rainfall pattern alternates between wet and dry seasons as the ITCZ follows the sun and where annual monsoonal rain occurs. ITCZ convective rainfall is the dominant style of precipitation but this can be influenced by rare intra-tropical cyclone events, and by atmospheric river events set up by strong monsoonal conditions. Though a rainy season is normal (for example, portions of India discharge in summer may reach 50 times that of winter), the actual rainfall events are in the form of short bursts of precipitation (hours to days) separated by periods of dry (hours to weeks). Some areas of the tropics receive more than 100 thunderstorms per year. Rivers respond to this punctuated weather by seasonal flooding. For the smaller island nations and locales (e.g. Indonesia, Philippines, Borneo, Hainan, PNG, Madagascar, Hawaii, Taiwan) flash floods are common. Larger tropical river systems (Niger, Ganges, Brahmaputra, Congo, Amazon, Orinoco, Magdalena) show typical seasonally modulated discharges. The sediment flux from tropical rivers is approximately 17% to 19% of the global total - however individual river basins offer a wide range in sediment yields reflecting highly variable differences in their hinterland lithology, tectonic activity and volcanism, land-sliding, and relief. Human influences also greatly influence the range for tropical river sediment yield. Some SE Asian Rivers continue to be greatly affected by deforestation, road construction, and monoculture plantations. Sediment flux is more than twice the pre-Anthropocene flux in many of these SE Asian countries, especially where dams and reservoir emplacements do not impact sediment delivery, as is the case in most temperate regions.

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

2011-12-01

351

The effect of manipulations of freshwater sediments on responses of benthic invertebrates in whole-sediment toxicity tests  

SciTech Connect

Manipulations of freshwater sediment were performed to remove indigenous organisms prior to conducting toxicity tests with three species of benthic invertebrates. The effects of these treatments on end points in bioassays were compared within and between two sediments, i.e., a ``clean`` sediment and a ``contaminated`` sediment. In addition, the effects of manipulations on the physicochemical structure of the two sediments and the presence of metals, PAHs, and PCBs in the contaminated sediment were examined. The amphipod Hyalella azteca was most sensitive to the manipulations and had low survival in sediment that was sterilized. Growth (milligrams dry weight per individual) was affected by the presence of contaminants. Survival of Chironomus riparius was not affected by any manipulation but was reduced by contaminants as well as indigenous organisms. Growth of C. riparius was higher in autoclaved sediment but lower in sediment containing endemic tubificid worms. Production of young by Tubifex tubifex increased in sediment that was irradiated, possibly due to increased detrital material. Particle size distribution, metals, nutrients, and PAHs varied little as a function of manipulation; however, sieving of sediment through 250-{micro}m mesh did reduce percent total organic carbon (TOC), percent loss on ignition (LOI), and concentrations of some PCBs in either clean or contaminated sediment. Manipulation of sediments to remove endemic species should be determined on a case-by-case basis and is specific to the organisms used in toxicity tests.

Day, K.E.; Kirby, R.S.; Reynoldson, T.B. [National Water Research Inst., Burlington, Ontario (Canada). Dept. of the Environment

1995-08-01

352

Wetland sedimentation from hurricanes Katrina and Rita.  

PubMed

More than 131 x 10(6) metric tons (MT) of inorganic sediments accumulated in coastal wetlands when Hurricanes Katrina and Rita crossed the Louisiana coast in 2005, plus another 281 x 10(6) MT when accumulation was prorated for open water area. The annualized combined amount of inorganic sediments per hurricane equals (i) 12% of the Mississippi River's suspended load, (ii) 5.5 times the inorganic load delivered by overbank flooding before flood protection levees were constructed, and (iii) 227 times the amount introduced by a river diversion built for wetland restoration. The accumulation from hurricanes is sufficient to account for all the inorganic sediments in healthy saltmarsh wetlands. PMID:16990516

Turner, R Eugene; Baustian, Joseph J; Swenson, Erick M; Spicer, Jennifer S

2006-10-20

353

Field methods for measurement of fluvial sediment  

USGS Publications Warehouse

This chapter describes equipment and procedures for collection and measurement of fluvial sediment. The complexity of the hydrologic and physical environments and man's ever-increasing data needs make it essential for those responsible for the collection of sediment data to be aware of basic concepts involved in processes of erosion, transport, deposition of sediment, and equipment and procedures necessary to representatively collect sediment data. In addition to an introduction, the chapter has two major sections. The 'Sediment-Sampling Equipment' section encompasses discussions of characteristics and limitations of various models of depth- and point-integrating samplers, single-stage samplers, bed-material samplers, bedload samplers, automatic pumping samplers, and support equipment. The 'Sediment-Sampling Techniques'` section includes discussions of representative sampling criteria, characteristics of sampling sites, equipment selection relative to the sampling conditions and needs, depth and point-integration techniques, surface and dip sampling, determination of transit rates, sampling programs and related data, cold-weather sampling, bed-material and bedload sampling, measuring total sediment discharge, and measuring reservoir sedimentation rates.

Edwards, Thomas K.; Glysson, G. Douglas

1999-01-01

354

Evaluation of sediment yield and sediment data-collection network in the Piceance basin, northwestern Colorado  

USGS Publications Warehouse

Statistical relationships were developed between suspended-sediment discharge and several regional factors of climate, physiography, and land use in the Piceance basin, northwestern Colorado. The purpose of the study was to evaluate the existing sediment collection network, especially in regard to detecting changes in suspended-sediment discharge due to the development in the basin. Spatial- and time variability were examined using multiple linear regression techniques. Because of the short period of record, monthly mean sediment loads were used to determine shifts or changes in trends due to mining and related activities in the basin. Dummy variable analysis was used to detect these premining and postmining differences in the regression lines and also to detect seasonal differences in the sediment discharge. Differences did exist in the sediment discharge from season to season and before and after mining; however, due to the variability and short period of record the cause of these differences could not be adequately determined. Part of the high variability in sediment discharge was due to variability in the water discharge. Therefore, if the network is to be improved, the emphasis needs to be on improvement of the water-discharge. The results of the monthly mean regression analysis were used in the mean monthly and mean annual analysis for determination of initial network design equations. These were only preliminary in nature and could be improved with additional data. (USGS)

Kircher, J.E.; Von Guerard, Paul

1982-01-01

355

Effect of water-column pH on sediment-phosphorus release rates in Upper Klamath Lake, Oregon, 2001  

USGS Publications Warehouse

Sediment-phosphorus release rates as a function of pH were determined in laboratory experiments for sediment and water samples collected from Shoalwater Bay in Upper Klamath Lake, Oregon, in 2001. Aerial release rates for a stable sediment/water interface that is representative of the sediment surface area to water column volume ratio (1:3) observed in the lake and volumetric release rates for resuspended sediment events were determined at three different pH values (8.1, 9.2, 10.2). Ambient water column pH (8.1) was maintained by sparging study columns with atmospheric air. Elevation of the water column pH to 9.2 was achieved through the removal of dissolved carbon dioxide by sparging with carbon dioxide-reduced air, partially simulating water chemistry changes that occur during algal photosynthesis. Further elevation of the pH to 10.2 was achieved by the addition of sodium hydroxide, which doubled average alkalinities in the study columns from about 1 to 2 milliequivalents per liter. Upper Klamath Lake sediments collected from the lake bottom and then placed in contact with lake water, either at a stable sediment/water interface or by resuspension, exhibited an initial capacity to take up soluble reactive phosphorus (SRP) from the water column rather than release phosphorus to the water column. At a higher pH this initial uptake of phosphorus is slowed, but not stopped. This initial phase was followed by a reversal in which the sediments began to release SRP back into the water column. The release rate of phosphorus 30 to 40 days after suspension of sediments in the columns was 0.5 mg/L/day (micrograms per liter per day) at pH 8, and 0.9 mg/L/day at pH 10, indicating that the higher pH increased the rate of phosphorus release by a factor of about two. The highest determined rate of release was approximately 10% (percent) of the rate required to explain the annual internal loading to Upper Klamath Lake from the sediments as calculated from a lake-wide mass balance and observed in total phosphorus data collected at individual locations.

Fisher, Lawrence H.; Wood, Tamara M.

2004-01-01

356

Changes in sediment volume in Alder Lake, Nisqually River Basin, Washington, 1945-2011  

USGS Publications Warehouse

The Nisqually River drains the southwest slopes of Mount Rainier, a glaciated stratovolcano in the Cascade Range of western Washington. The Nisqually River was impounded behind Alder Dam when the dam was completed in 1945 and formed Alder Lake. This report quantifies the volume of sediment deposited by the Nisqually and Little Nisqually Rivers in their respective deltas in Alder Lake since 1945. Four digital elevation surfaces were generated from historical contour maps from 1945, 1956, and 1985, and a bathymetric survey from 2011. These surfaces were used to compute changes in sediment volume since 1945. Estimates of the volume of sediment deposited in Alder Lake between 1945 and 2011 were focused in three areas: (1) the Nisqually River delta, (2) the main body of Alder Lake, along a 40-meter wide corridor of the pre-dam Nisqually River, and (3) the Little Nisqually River delta. In each of these areas the net deposition over the 66-year period was 42,000,000 ± 4,000,000 cubic meters (m3), 2,000,000 ± 600,000 m3, and 310,000 ± 110,000 m3, respectively. These volumes correspond to annual rates of accumulation of 630,000 ± 60,000 m3/yr, 33,000 ± 9,000 m3/yr, and 4,700 ± 1,600 m3/yr, respectively. The annual sediment yield of the Nisqually (1,100 ± 100 cubic meters per year per square kilometer [(m3/yr)/km2]) and Little Nisqually River basins [70 ± 24 (m3/yr)/km2] provides insight into the yield of two basins with different land cover and geomorphic processes. These estimates suggest that a basin draining a glaciated stratovolcano yields approximately 15 times more sediment than a basin draining forested uplands in the Cascade Range. Given the cumulative net change in sediment volume in the Nisqually River delta in Alder Lake, the total capacity of Alder Lake since 1945 decreased about 3 percent by 1956, 8 percent by 1985, and 15 percent by 2011.

Czuba, Jonathan A.; Olsen, Theresa D.; Czuba, Christiana R.; Magirl, Christopher S.; Gish, Casey C.

2012-01-01

357

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

NASA Astrophysics Data System (ADS)

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 1.5 cm/a (erosion pins), 1.4 cm/a (suspended sediment) and 1.6 cm/a (repeat Tripod LiDAR). These rates are at least 100-fold greater than the long-term river lowering rate of 0.13 mm/a. A sediment budget constructed by extrapolating hillslope lowering rates to the portions of the catchments mapped as unvegetated overland flow predicts a total yearly flux of ~ 6500 t, in agreement with the measured total of ~6200 t. Decadal records illustrate that rainfall intensities sufficient to generate overland flow occur for at least 8-10 hours every year, coincident with 1-3 large storm events. We hypothesize that high lowering rates reflect a combination of long-duration overland flow events, and availability of weathered soils that can be entrained by thin flow. It appears that generation of loose, seasonally weathered silt is a 1st order control on the amount of sediment exported to the reef. If climate change increases storm frequency or duration, or decreases vegetation cover, sediment loading to reefs could increase dramatically.

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

2010-12-01

358

A reconnaissance of stream sediment in the Erie-Niagara basin, New York  

USGS Publications Warehouse

This reconnaissance study of erosion and deposition of sediment in the Erie-Niagara basin indicates that the highest sediment yields, on the order of 1,000 tons per square mile per year, occur in streams that drain upland areas. In contrast, for example, from the lowland part of the Tonawanda Creek basin, the annual sediment yields are on the order of 100 tons per square mile per year. The estimated average annual sediment yields of streams in the basin range from 50 tons per square mile for Little Tonawanda Creek at Linden, to 1,500 tons per square mile for Cazenovia Creek at Ebenezer. These estimates are based on measured instantaneous sediment discharge at selected stream stations, the sediment loads of which ranged from 1,100 tons per year for Little Tonawanda Creek at Linden to 610,000 tons per year for Cattaraugus Creek at Gowanda. The accuracy of the estimates of average annual sediment discharge could be considerably improved by the collection of additional data. Nevertheless, the estimates are believed to be indicative of the magnitude of sediment yields and provide a general description of stream-sediment movement in the study area. Peak suspended-sediment concentrations in the range of 2,600 to 5,300 ppm (parts per million) were observed at three stations in the Cattaraugus Creek basin, as well as at Buffalo Creek at Gardenville, Cazenovia Creek at Ebenezer, and Cayuga Creek near Lancaster.

Archer, R.J.; La Sala, A.M., Jr.

1968-01-01

359

Monsoon sedimentation on the ‘abandoned' tide-influenced Ganges-Brahmaputra delta plain  

NASA Astrophysics Data System (ADS)

Annual sediment delivery by the Ganges and Brahmaputra rivers to the Bengal margin has kept pace with sea level rise since the mid Holocene, sustaining subaerial growth of the delta. However, the Sundarbans region of the tidal delta is disconnected from major distributary sources of sediment and is often thought to be sediment starved, eroding, and susceptible to the meter of sea level rise predicted for the 21st century. Despite these assumptions, direct sedimentation measurements on the tidal delta plain reveal widespread mean annualized accretion rates of ?1.1 cm yr-1, although heterogeneous depositional patterns indicate that topography and internal creek networks influence local sediment distribution. Short-lived radioisotope inventories (7Be: t1/2 = 53.3 days) measured on the freshly accumulated sediments indicate that about ½ of the mass deposited on the lower delta was sourced directly from the seasonal flood pulse of the river; the remaining ½ is derived from older (?1 yr) reworked sediments. Net sedimentation on this part of the delta traps ?10% of annual Ganges-Brahmaputra sediment load, with accretion rates roughly equivalent to the mean regional rate of relative sea-level rise (RSLR) of ?1.0 cm yr-1. If these sedimentation rates are representative of longer-term trends and subsidence rates remain stable over the next century, the lower delta plain may continue to maintain its elevation and stability despite documented mangrove retreat around its seaward edges.

Rogers, Kimberly G.; Goodbred, Steven L.; Mondal, Dhiman R.

2013-10-01

360

Diversity and distribution of bacterial communities in dioxin-contaminated sediments from the Houston ship channel  

E-print Network

the presence or absence of Dehalococcoides in HSC sediments. Molecular methods including PCR, cloning, restriction enzyme digest, and sequencing were used to determine the diversity of Dehalococcoides as well as total bacterial diversity in HSC sediments...

Hieke, Anne-Sophie Charlotte

2009-05-15

361

Sedimentation and the economics of selecting an optimum reservoir size  

SciTech Connect

An easily reproducible methodology is presented for the economic selection of an optimal reservoir size given an annual sedimentation rate. The optimal capacity is that at which the marginal cost of constructing additional storage capacity is equal to the dredging costs avoided by having that additional capacity available to store sediment. The cost implications of misestimating dredging costs, construction costs, and sediment delivery rates are investigated. In general, it is shown that oversizing is a rational response to uncertainty in the estimation of parameters. The sensitivity of the results to alternative discount rates is also discussed. The theoretical discussion is illustrated with a case study drawn from Highland Silver Lake in southwestern Illinois.

Miltz, D.; White, D.C.

1987-08-01

362

Sediment losses and gains across a gradient of livestock grazing and plant invasion in a cool, semi-arid grassland, Colorado Plateau, USA  

Microsoft Academic Search

Large sediment fluxes can have significant impacts on ecosystems. We measured incoming and outgoing sediment across a gradient of soil disturbance (livestock grazing, plowing) and annual plant invasion for 9years. Our sites included two currently ungrazed sites: one never grazed by livestock and dominated by perennial grasses\\/well-developed biocrusts and one not grazed since 1974 and dominated by annual weeds with

Jayne Belnap; Richard L. Reynolds; Marith C. Reheis; Susan L. Phillips; Frank E. Urban; Harland L. Goldstein

2009-01-01

363

Impact of a large tropical reservoir on riverine transport of sediment, carbon, and nutrients to downstream wetlands  

NASA Astrophysics Data System (ADS)

Large dams can have major ecological and biogeochemical impacts on downstream ecosystems such as wetlands and riparian habitats. We examined sediment removal and carbon (C), nitrogen (N), and phosphorus (P) cycling in Itezhi-Tezhi Reservoir (ITT; area = 364 km2, hydraulic residence time = 0.7 yr), which is located directly upstream of a high ecological value floodplain ecosystem (Kafue Flats) in the Zambezi River Basin. Field investigations (sediment cores, sediment traps, water column samples), mass balance estimates, and a numerical biogeochemical reservoir model were combined to estimate N, P, C, and sediment removal, organic C mineralization, primary production, and N fixation. Since dam completion in 1978, 330 × 103 tons (t) of sediment and 16 × 103, 1.5 × 103, 200 t of C, N, and P, respectively, have accumulated annually in ITT sediments. Approximately 50% of N inputs and 60% of P inputs are removed by the reservoir, illustrating its potential in decreasing nutrients to the downstream Kafue Flats floodplain. The biogeochemical model predicted substantial primary production in ITT (˜280 g C m-2 yr-1), and significant N-fixation (˜30% for the total primary production) was required to support primary production due to marginal inputs of inorganic N. Model simulations indicate that future hydropower development in the reservoir, involving the installation of turbines driven by hypolimnetic water, will likely result in the delivery of low-oxygen waters to downstream ecosystems and increased outputs of dissolved inorganic N and P by a factor of ˜4 and ˜2 compared to current dam management, respectively.

Kunz, Manuel J.; Wüest, Alfred; Wehrli, Bernhard; Landert, Jan; Senn, David B.

2011-12-01

364

Assessing upper Mississippi River sediments using benthic invertebrates and the sediment quality triad  

SciTech Connect

Benthic invertebrate samples were collected from 23 pools in the Upper Mississippi River (UMR) and from one station in the Saint Croix River (SCR) as part of study to assess the effects of the extensive flooding of 1993 on sediment contamination in the UMR system. Sediment contamination consists of organic and inorganic contaminants. Samples were collected with a petite ponar grab sampler Oligochaete and Chironomid abundance constituted over 80% of the community in samples from 18 of 23 pools in the UMR and in the SCR sample. Fingernail clams comprised a large portion of the community in 5 of 23 UMR pools. Total abundance values ranged from 333/m{sup 2} at pool 1 to 25,000/m{sup 2} at pool 19. Overall frequency of chironomid mouth part deformities was 3%, which is comparable to literature values for incidence of deformities in uncontaminated sediments. Occurrence of mouth part deformities ranged 0 to 13% at the UMR pools. Sediment contamination was generally low in the UMR pools and the SCR site. The degree of sediment contamination will be evaluated with data from laboratory toxicity exposures, sediment chemistry analyses and benthic community analyses using the Sediment Quality Triad approach. Preliminary evaluations show the sediments from the UMR and SCR are relatively uncontaminated and the flooding of `93 did not adversely effect sediment quality in the UMR system.

Canfield, T.J.; Brunson, E.L.; Dwyer, F.J.; Ingersoll, C.G.; Kemble, N.E. [National Biological Service, Columbia, MO (United States). Midwest Science Center

1995-12-31

365

Fluvial sediment concepts  

USGS Publications Warehouse

This report is the first of a series concerned with the measurement of and recording of information about fluvial sediment and with related environmental data needed to maintain and improve basic sediment knowledge. Concepts presented in this report involve (1) the physical characteristics of sediment which include aspects relative 'to weathering, soils, resistance to erosion, and particle size, (2) sediment erosion, transport, and deposition characteristics, which include aspects relative to fine sediment and overland flow, coarse sediment and streamflow, variations in stream sediment concentration, deposition, and denudation, (3) geomorphic considerations, which include aspects relative to the drainage basin, mass wasting, and channel properties, (4) economic aspects, and (5) data needs and program objectives to be attained through the use of several kinds of sediment records.

Guy, Harold P.

1970-01-01

366

The paleoenvironmental and climatic recorded in core sediments of Lake Abashiri in the east part of Hokkaido, Japan  

NASA Astrophysics Data System (ADS)

In the coastal area of the Sea of Okhotsk in the east part of Hokkaido located to for subarctic zone, many brackish-water lakes are distributed. Especially, the Okhotsk brackish-water lake group around Abashiri City is constituted by major lake in Japan such as Lake Abashiri, Lake Mokoto, Lake Tofutsu, and Lake Notoro. The each lake shows a different present environment and history. Therefore, the change that is common in those lakes seems to be the change concerning the climate. In this study, paleoenvironmental and climatic changes after the Little Ice Age in Abashiri region is discussed by sedimentologic and geochemical high-resolution analysis of the 4m-sediment cores collected from the Lake Abashiri. The water column of Lake Abashiri has a distinct halocline around 5m depths, and is divided into oligohaline epilimnion and polyhaline hypolimnion by its pycnocline. The hypolimnion in Lake Abashiri shows the euxinic conditions throughout the annual. Therefore, surface sediment of below water depth 5m shows the black organic mud with the lamination. The 10AB-5C core collected from Lake Abashiri shows the length of 332cm. This core is composed of muddy sediment with a distinct lamination through all horizons. The Ta-a tephra (AD 1739) and Ko-c2 tephra (AD 1694) are found at the horizon of 250 cm, and 291 cm, respectively. Sedimentation rate based on these ages was 0.92cm/yr between Ko-c2 tephra and Ta-a tephra, and was 0.91cm/yr between surface and Ta-a tephra. The result of observation used by Soft X-ray photograph, the lamina-set of high, low, intermediate density layers was observed. The lamina set of 44 was recognized between Ko-c2 tephra and Ta-a tephra. This is suggested that this set is annual lamina (varve). If its so, it is considered that high density layer indicate the high precipitation term of summer season judging from precipitation pattern in Abashiri Area. Particularly, the year of flood events tend to show a thick and distinguished layer in lamina-set. The high-density lamina-set group is repeated with 20 to 30 year cycle. The horizon of high-density lamina-set group is correlated with the term showing several years continuously high precipitation. This lamina-set group is observed from 400 years ago, the climate system would have been continued. In order to clarify the formation process of the lamina set in Lake Abashiri, we are observed by a sediment trap. Sediment traps are set up above 2m from lake bottom in water mass under euxinic environment. Result of this observation, sediment flux is increased in early spring (ice melting) and late summer (flood) seasons. Sediment flux in early spring season is higher than late summer season. Total organic carbon (TOC) contents of trapped sediment are higher than surface sediments except for trapped sediment in early spring season. These are suggested that low-density layer indicate in early spring (ice melting) season. In winter (ice) and early summer seasons, the sediment flux is low, and TOC contents show the high value. This is suggested that the limited supply of inorganic sediment. In this time, the diatom lamina may been formed in lamina set.

Seto, K.; Katsuki, K.; Sonoda, T.; Kawajiri, T.; Watanabe, T.

2013-12-01

367

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

USGS Publications Warehouse

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 early summer (June through July), with fall (October through November) and early winter (December through January) contributing the smallest loadings. The Northern Lakes and Forests/North Central Hardwoods region had some substantial loading in September. There was a similar pattern for total phosphorus loading in all regions, with the pattern somewhat less pronounced in urban watersheds. As with the loading results, average monthly streamflow values were greatest in late winter, spring, and early summer, with the lowest values typically in fall and early winter. Loading contributions were greater from stormflow than from base flow in all instances, except total phosphorus in the Northern Lakes and Forests/North Central Hardwoods region, which had equal or greater base-flow contribution for several months. Base flow constituted a greater percentage of the total streamflow than stormflow in all rural watersheds for all regions. Only a few storms each year dominated the annual loading totals for solids and total phosphorus. When daily loading values were ranked for the year, all regions reached 50 percent of the annual solids loading in the 5 highest loading days and nearly 50 percent of the annual total phosphorus loading in the 14 highest loading days.

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

2010-01-01

368

Alpine climate during the Holocene: a comparison between records of glaciers, lake sediments and solar  

E-print Network

Alpine climate during the Holocene: a comparison between records of glaciers, lake sediments in Alpine glacier length records and climate reconstructions from annually laminated sediments of Alpine millennium: mass accumulation rates and biogenic silica concentration are largely in phase with the glacier

Wehrli, Bernhard

369

Sediment Flushing at the Nakdong River Estuary Barrage ; P. Y. Julien, M.ASCE2  

E-print Network

mechanical dredging to maintain the flood conveyance capacity during typhoons. This analysis focuses on the possibility of replacing mechanical dredging with sediment flushing through gate operations changes at NREB, about 54% of the mean annual dredging volume could be eliminated by sediment flushing at NREB. The model

Julien, Pierre Y.

370

Recent changes of water discharge and sediment load in the Zhujiang (Pearl River) Basin, China  

Microsoft Academic Search

The paper is concerned with identifying changes in the time series of water and sediment discharge of the Zhujiang (Pearl River), China. The gradual trend test (Mann–Kendall test), and abrupt change test (Pettitt test), have been employed on annual water discharge and sediment load series (from the 1950s–2004) at nine stations in the main channels and main tributaries of the

Shurong Zhang; Xi Xi Lu; David L. Higgitt; Chen-Tung Arthur Chen; Jingtai Han; Huiguo Sun

2008-01-01

371

A Comparison of Past Dam Removals in Highly Sediment Impacted Systems  

Microsoft Academic Search

The ability to predict the effects of dam removal in highly sediment filled systems is increasingly important as the number of such dam removal cases continues to grow annually. The cost and potential impacts of dam removal are site specific and can vary substantially depending on local conditions. Of specific concern in sediment impacted removals is the volume and rate