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1

Sediment Total Maximum Daily Loads (TMDLs) Glossary  

EPA Pesticide Factsheets

Water Quality:  The biological, chemical, and physical conditions of a waterbody. It is a measure of a waterbody's ability to support beneficial uses.   From Sediment Total Maximum Daily Loads (TMDLs) Glossary  -  Search all glossaries for terms containing water quality

2012-12-10

2

24 CFR 886.308 - Maximum total annual contract commitment.  

Code of Federal Regulations, 2013 CFR

...false Maximum total annual contract commitment. 886.308 Section 886.308 ...308 Maximum total annual contract commitment. (a) Number of units assisted...by which the maximum annual contract commitment per year exceeds amounts paid...

2013-04-01

3

Interdecadal patterns of total sediment yield from a montane catchment, southern Coast Mountains, British Columbia, Canada  

Microsoft Academic Search

We reconstruct sediment yield for a mountain watershed of western Canada since the mid-twentieth century from studies of annually laminated lake sediments, delta progradation, and solute transfer. Total yield averaged 320±40Mgkm?2a?1 and comprised ?35% suspended load, 50% bedload, and 15% dissolved load. Ratios between the individual yield components varied approximately threefold at interannual timescales because of significant variability in the

Erik Schiefer; Marwan A. Hassan; Brian Menounos; Channa P. Pelpola; Olav Slaymaker

2010-01-01

4

Concentrations and annual ?uxes of sediment-associated chemical constituents from conterminous US coastal rivers using bed sediment data  

USGS Publications Warehouse

Coastal rivers represent a significant pathway for the delivery of natural and anthropogenic sediment-associated chemical constituents to the Atlantic, Pacific and Gulf of Mexico coasts of the conterminous USA. This study entails an accounting segment using published average annual suspended sediment fluxes with published sediment-associated chemical constituent concentrations for (1) baseline, (2) land-use distributions, (3) population density, and (4) worldwide means to estimate concentrations/annual fluxes for trace/major elements and total phosphorus, total organic and inorganic carbon, total nitrogen, and sulphur, for 131 coastal river basins. In addition, it entails a sampling and subsequent chemical analysis segment that provides a level of ‘ground truth’ for the calculated values, as well as generating baselines for sediment-associated concentrations/fluxes against which future changes can be evaluated. Currently, between 260 and 270 Mt of suspended sediment are discharged annually from the conterminous USA; about 69% is discharged from Gulf rivers (n = 36), about 24% from Pacific rivers (n = 42), and about 7% from Atlantic rivers (n = 54). Elevated sediment-associated chemical concentrations relative to baseline levels occur in the reverse order of sediment discharges:Atlantic rivers (49%)>Pacific rivers (40%)>Gulf rivers (23%). Elevated trace element concentrations (e.g. Cu, Hg, Pb, Zn) frequently occur in association with present/former industrial areas and/or urban centres, particularly along the northeast Atlantic coast. Elevated carbon and nutrient concentrations occur along both the Atlantic and Gulf coasts but are dominated by rivers in the urban northeast and by southeastern and Gulf coast (Florida) ‘blackwater’ streams. Elevated Ca, Mg, K, and Na distributions tend to reflect local petrology, whereas elevated Ti, S, Fe, and Al concentrations are ubiquitous, possibly because they have substantial natural as well as anthropogenic sources. Almost all the elevated sediment-associated chemical concentrations found in conterminous US coastal rivers are lower than worldwide averages.

Horowitz, Arthur J.; Stephens, Verlin C.; Elrick, Kent A.; Smith, James J.

2012-01-01

5

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...

6

Relationship between sediment clay minerals and total mercury.  

PubMed

A group of 262 sediment samples were collected from various lakes, rivers, reservoirs, and bayous of Louisiana. All samples were analyzed for total mercury. Twenty nine of the samples with total mercury content ranging from 11 to 401 ppb (?g/kg) were analyzed for clay minerals and other sediment physical and chemical properties. Clay content in sediments varied from 3 to 72%. Clay minerals were determined by X-ray diffraction (XRD) technique. Identification of clay minerals was determined by MacDiff software and quantification of clay minerals was obtained by Peak Height Percentage (PHP) calculation. The dominant clay mineral was Hydrated Interlayer Vermiculite (HIV), which represented 51-83% of the total clay mineral. Significant linear correlations were observed between Hg and total clay content (r=0.538**). However Smectite was the only individual clay type correlated (r=0.465**) with mercury in sediment. Cation exchange capacity (r=0.404*), organic matter (r=0.577**), and sulfur (r=0.676**) were also correlated significantly with mercury level in sediment. PMID:21469014

Kongchum, Manoch; Hudnall, Wayne H; DeLaune, R D

2011-01-01

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

Models to predict lake annual mean total phosphorus  

Microsoft Academic Search

A lake is a product of processes in its watershed, and these relationships should be empirically quantifiable. Yet few studies have made that attempt. This study quantifies and ranks variables of significance to predict annual mean values of total phosphorus (TP) in small glacial lakes. Several new empirical models based on water chemistry variables, on ‘map parameters’ of the lake

Lars Hfikanson

1995-01-01

10

Paleolimnological studies of annually-laminated sediments in Loe Pool, Cornwall, U.K  

Microsoft Academic Search

The sediments of Loe Pool, a eutrophic coastal lake in south west England, consist largely of laminated clays and clay-gyttjas. Studies of the diatom microstratigraphy of frozen sediment cores from the Pool indicate that the laminations are annual, and that they contain pairs of light and dark bands formed by seasonal variations in the supply of sediment to the Pool

M. A. Coard; S. M. Cousen; A. H. Cuttler; H. J. Dean; J. A. Dearing; T. I. Eglinton; A. M. Greaves; K. P. Lacey; P. E. O'Sullivan; D. A. Pickering; M. M. Rhead; J. K. Rodwell; H. Simola

1983-01-01

11

Distribution of Total Mercury and Methyl Mercury in Water, Sediment, and Fish from South Florida Estuaries  

Microsoft Academic Search

.   Concentrations of total mercury and methyl mercury were determined in sediment and fish collected from estuarine waters\\u000a of Florida to understand their distribution and partitioning. Total mercury concentrations in sediments ranged from 1 to 219\\u000a ng\\/g dry wt. Methyl mercury accounted for, on average, 0.77% of total mercury in sediment. Methyl mercury concentrations were\\u000a not correlated with total mercury

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

1998-01-01

12

Impregnation method for detecting annual laminations in sediment cores: An overview  

Microsoft Academic Search

Annually laminated sediments can provide an absolute time scale (by varve counting) and a high-resolution palaeoclimate information (from varve thickness). Both types of information may be directly measured from sediment core surfaces. In this paper, we stress that varve counting and varve thickness measurements derived from fresh core surfaces could not systematically reveal the internal sedimentary structure, even if assisted

Xavier Boës; Nathalie Fagel

2005-01-01

13

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

14

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

15

PCB congeners and hexachlorobenzene biota sediment accumulation factors for Macoma nasuta exposed to sediments with different total organic carbon contents  

SciTech Connect

Deposit-feeding marine clams (Macoma nasuta) were exposed for 119 d to three sediment types that varied in total organic carbon (TOC) from 0.8 to 2.5%. Sediments were spiked with equal concentrations of 13 polychlorinated biphenyl congeners and hexachlorobenzene. Tissue residues were measured, and steady-state bioaccumulation factors (BAFs), the corresponding lipid, and TOC-normalized biota sediment accumulation factors (BSAFs) were determined. The BSAFs were less variable than were the BAFs with the exception of compounds with log K[sub ow] > 7. Many of the BSAFs exceeded 1.7, which is a calculated maximum value based on partitioning alone. Although BSAFs varied with sediment type and compound, the use of a BSAF of 4 as a screening level for neutral organic compounds in assessing dredge materials is supported by the present study.

Boese, B.L.; Lee, H. II; Randall, R. (Environmental Protection Agency, Newport, OR (United States). Pacific Ecosystems Branch); Winsor, M.; Echols, S.; Pelletier, J. (AScI, Newport, OR (United States). Hatfield Marine Science Center)

1995-02-01

16

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...

17

Total nutrient and sediment loads, trends, yields, and nontidal water-quality indicators for selected nontidal stations, Chesapeake Bay Watershed, 1985–2011  

USGS Publications Warehouse

The U.S. Geological Survey, in cooperation with Chesapeake Bay Program (CBP) partners, routinely reports long-term concentration trends and monthly and annual constituent loads for stream water-quality monitoring stations across the Chesapeake Bay watershed. This report documents flow-adjusted trends in sediment and total nitrogen and phosphorus concentrations for 31 stations in the years 1985–2011 and for 32 stations in the years 2002–2011. Sediment and total nitrogen and phosphorus yields for 65 stations are presented for the years 2006–2011. A combined nontidal water-quality indicator (based on both trends and yields) indicates there are more stations classified as “improving water-quality trend and a low yield” than “degrading water-quality trend and a high yield” for total nitrogen. The same type of 2-way classification for total phosphorus and sediment results in equal numbers of stations in each indicator class.

Langland, Michael J.; Blomquist, Joel D.; Moyer, Douglas L.; Hyer, Kenneth E.; Chanat, Jeffrey G.

2013-01-01

18

Estimated 1996--97 and long-term average annual loads for suspended sediment and selected trace metals in streamflow of the upper Clark Fork Basin from Warm Springs to Missoula, Montana  

SciTech Connect

The report presents annual load estimates for suspended sediment and selected trace metals in streamflow at 12 sites in the upper Clark Fork basin from Warm Springs to Missoula during water years 1996-97. Annual constituent loads were calculated using constituent concentrations measured in periodically collected samples, data from daily suspended-sediment and streamflow records, and regression relations. The resulting loads are summarized to provide a spatial characterization of sediment and metals inputs during 1996-97. Methods used to calculate loads are presented for suspended sediment, total-recoverable copper, lead, and zinc, and dissolved copper.

Lambing, J.H.

1998-08-01

19

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, N.; Schoellhamer, D.

2006-08-01

20

Comparability of Suspended-Sediment Concentration and Total Suspended Solids Data.  

National Technical Information Service (NTIS)

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 di...

J. R. Gray G. D. Glysson L. M. Turcios G. E. Schwarz

2000-01-01

21

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

22

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

23

Quantitative PCR enumeration of total/toxic Planktothrix rubescens and total cyanobacteria in preserved DNA isolated from lake sediments.  

PubMed

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

2011-10-07

24

Ecosystem engineering by annual intertidal seagrass beds: Sediment accretion and modification  

NASA Astrophysics Data System (ADS)

Seagrasses are generally known as ecosystem engineers, as they reduce flow velocities in their canopies. In perennial subtidal meadows, this usually leads to increased net sedimentation rates and reduction of the grain size. The present study aims to describe the contribution of annual seagrass populations to these processes and elucidate the temporal dynamics. Sediment accretion and grain size modification were experimentally tested by transplanting seedlings of an annual intertidal eelgrass population to an unvegetated tidal flat. Within the planting units (79 shoots m-2) 4.7 mm of sediment accreted, whereas in the most dense parts of these units (199 shoots m-2) accretion amounted to 7.1 mm. The silt fraction (<63 ?m) increased and the sand fraction (63 500 ?m) decreased in the eelgrass beds, which provides evidence that higher silt content in seagrass beds is the result and not the cause of seagrass presence. Annual intertidal eelgrass beds significantly contribute to the immobilisation of sediment during the growing season with its magnitude depending on canopy density. During winter, the accumulated sediments were released again and could even induce additional erosion. Possible consequences of these sediment dynamics for the larger scale functioning of estuarine ecosystems are discussed.

Bos, Arthur R.; Bouma, Tjeerd J.; de Kort, Geertje L. J.; van Katwijk, Marieke M.

2007-08-01

25

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

Code of Federal Regulations, 2010 CFR

...Total Annual Loan Cost Rate Computations for Reverse Mortgage Transactions K Appendix K...Annual Loan Cost Rate Computations for Reverse Mortgage Transactions (a) Introduction...of total annual loan cost rates for each reverse mortgage transaction. This...

2010-01-01

26

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

Code of Federal Regulations, 2010 CFR

...Total Annual Loan Cost Rate Computations for Reverse Mortgage Transactions K Appendix K...Annual Loan Cost Rate Computations for Reverse Mortgage Transactions (a) Introduction...of total annual loan cost rates for each reverse mortgage transaction. This...

2009-01-01

27

Total phosphorus content of river sediments in relationship to calcium, iron and organic matter concentrations.  

PubMed

Data on the total concentrations of phosphorus, calcium, iron and organic matter in surface bed-sediments taken from rivers in the Thames catchment (Wey, Blackwater, Thame and Kennet), the River Swale in Yorkshire (data excludes the organic matter content) as well as the headwaters of the Great Ouse, are collated and compared. Total concentrations of phosphorus, iron and calcium range from 1.7-649, 12-8,333 and 9-4,605 micromol g(-1) (dry weight), respectively, with organic matter in the range of 0.6-19% by dry weight. For the Wey, Blackwater and Great Ouse, sewage inflows had no detectable effect on the sediment concentrations of total calcium, iron and organic matter whereas for the Blackwater and Great Ouse, the total phosphorus contents of the sediment were higher downstream of the effluent input in comparison with a less impacted upstream location. Relationships between the total phosphorus content of the sediments and contents of iron, calcium and organic matter indicated marked differences between the rivers. Although the organic matter content of the sediments was found to be a significant predictor for the total phosphorus concentration for the Blackwater and Great Ouse, the total iron content was also useful for the Blackwater and total calcium for the Great Ouse. It is postulated that this difference is a result of the sediment processes that are known to occur in these two systems, i.e. co-precipitation of phosphate with calcite in the Great Ouse and the formation of vivianite in anoxic sediments of the Blackwater. PMID:11846078

House, William A; Denison, Frank H

2002-01-23

28

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

29

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

Code of Federal Regulations, 2013 CFR

...false Maximum total annual contract commitment and project account (private-owner...104 Maximum total annual contract commitment and project account (private-owner... (a) Maximum total annual contract commitment. The maximum total annual...

2013-04-01

30

Total phosphorus content of river sediments in relationship to calcium, iron and organic matter concentrations  

Microsoft Academic Search

Data on the total concentrations of phosphorus, calcium, iron and organic matter in surface bed-sediments taken from rivers in the Thames catchment (Wey, Blackwater, Thame and Kennet), the River Swale in Yorkshire (data excludes the organic matter content) as well as the headwaters of the Great Ouse, are collated and compared. Total concentrations of phosphorus, iron and calcium range from

William A House; Frank H Denison

2002-01-01

31

Evidence of annual layering in Holocene sediments of Soppensee, Switzerland  

Microsoft Academic Search

A succession of fine dark and light laminations, covering a time span of ca 6,000 years (Allerød to Atlantic), was observed in the sediment of Soppensee, Central Switzerland. These laminations, consisting of dark, organic and diatom-rich winter\\/spring layers and light calcite summer layers, are shown to be varves by means of several independent pollen and diatom analyses, as well as

André F. Lotter

1989-01-01

32

Tributyltin and total tin in marine sediments: Profiles and the apparent rate of TBT degradation  

Microsoft Academic Search

Total tin and tributyltin (TBT) were measured in sediment cores collected from the Tamaki Estuary in Auckland. New Zealand. The total tin concentration ranged up to 6.2 ?g g and the TBT concentration ranged up to 0.759 ?g TBT?Sn g. While the maximum total tin values were observed adjacent to a storm water outfall, the highest surficial TBT levels were

S. J. de Mora; N. G. King; M. C. Miller

1989-01-01

33

Improving 14C-based chronologies of non-annually resolved sediment series by assessing the biogenic fraction flux instead of sedimentation rate  

NASA Astrophysics Data System (ADS)

The last decade was a period of unprecedented development of annually-resolved natural archives of past environmental conditions, such as speleothems, varve lake sediment, ice core or corals. Nevertheless, such geosystems are not present everywhere in the world and the interest for non-annually resolved natural archives remains important in the aim of reconstructing past climatic and environmental condition, both in marine and continental areas. In particular it has been shown that sediment - from lakes, fjords, or continental margins - which are made of a mixture of biogenic and detrital fractions, may be used to reconstruct past detrital discharge and thus hydrological patterns. Thanks to the recent developments in core logging geochemical techniques - XRF core scanning - such sediment sequences are susceptible to deliver highly resolute climatic of environmental signals, provided they may be accurately dated. In this paper we present a new method, applied to the establishment of age-depth relationships of two of such sequences taken in Lake Bourget, NW French Alps. Our method is classically based on 14C ages, but those ages were stratigraphically placed as a function of "biogenic carbonate accumulation" instead of depth below lake floor, which is classically done. Lake Bourget is a fjord-type lake in which river Rhône, one of the main European Alps rivers, sporadically enters during its major floods. Such events bring a silicate-rich detrital fraction which dilutes the biogenic carbonates constituting the main sediment fraction in normal conditions. Two long cores covering most of the Holocene period were retrieved in Lake Bourget and sampled for 14C dating following a sampling-step of less than 1000 years. Using high resolution XRF core scanning results calibrated by 150 major elements discrete measurements, we assessed carbonate and detrital fraction contents following a 5mm- to 1cm-step. We also assessed the evolution of dry density as a function of depth by measuring the dry weight of volume-known samples. Combining those information we were able to compute the weight of carbonate accumulation above each depth per surface unit (carbonate accumulation depth). 14C ages were subsequently replaced as a function of this "carbonate accumulation depth". It then appeared that all the ages were aligned along a linear curve. On the contrary, the age-depth relationship presents many disruptions due to changes in detrital flux. We hence demonstrate that biogenic carbonate flux varies of one order of magnitude less than total sediment flux. We finally applied a classic age-depth modelling to take account of low amplitude change in carbonate accumulation and thus establish an independent chronology of each sediment sequence. The chronology hence obtained takes account of instantaneous changes in detrital supply and is thus more accurate than classic age-depth relationship. The agreement of detrital signals as a function of time in our two independently dated sequences argues for the accuracy of our method. Such a method should improve age-modelling of any non-annually laminated sediment sequence which is made of a mixture of biogenic (carbonate, diatoms, organic matter etc.) and detrital fractions, whatever it is of freshwater or marine origin.

Arnaud, F.

2009-04-01

34

Geochemical and sedimentologic variations in inter-annually laminated sediments from Santa Monica Basin  

Microsoft Academic Search

Laminated sediments were recently discovered in the center of Santa Monica Basin, California Continental Borderland and extend from the present day to at least the Little Ice Age (ca. 1600 A.D.). Unlike the annual varves observed in Santa Barbara Basin, the light-dark lamination couplets observed in 210Pb-dated cores from the center of Santa Monica Basin occur at 3 to 6

James W. Hagadorn; Lowell D. Stott; Ashish Sinha; Miguel Rincon

1995-01-01

35

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

36

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

Code of Federal Regulations, 2010 CFR

The goods which the establishment purchases or receives for resale that move or have moved across State lines must âamount in total annual volume to $250,000 or more.â It will be noted that taxes are not excluded in measuring this annual dollar...

2010-07-01

37

Monthly and annual suspended-sediment loads in the Brazos River at Richmond, Texas, 1966-86 water years  

USGS Publications Warehouse

Sampling to determine suspended-sediment concentrations at Brazos River at Richmond, Texas, station 08114000 began in January 1966 and ended in September 1986. Depth-integrated samples were collected in all flow conditions. The records for this station are considered good. The mean monthly suspended-sediment load in the Brazos River at Richmond ranged from 2,500 to 91,000 tons during the period of record. The annual suspended-sediment load at Brazos River at Richmond ranged from 404,500 to 30,800,000 tons and averaged about 10,900 ,000 tons. The minimum annual load of 404,500 tons occurred during the 1984 water year, and the maximum annual load of 30 ,800,000 tons occurred during the 1968 water year. Suspended-sediment load and discharge varied throughout the period of study. A double-mass curve indicated that the relation between discharge and sediment load remained constant. No breaks were noted, indicating that no change occurred in the relation. The data collected annually during the study were used to define a regression model. The model was found to be a good predictor of annual suspended-sediment load by using annual streamflow as the independent variable. (USGS)

Andrews, F. L.

1989-01-01

38

Statistical analysis and estimation of annual suspended sediments of major rivers in Japan.  

PubMed

We evaluate the spatiotemporal trends of recent suspended sediment conditions in Japanese rivers. Statistical and spatiotemporal trend analysis is conducted on the 92 major rivers in Japan based on water quality monitoring data from 1992 to 2005. The Mann-Kendall non-parametric method was used to investigate the spatial and temporal trends for the suspended sediment indicator. Results show that the mean concentration of suspended sediments in Japanese rivers has generally declined in recent years, although there are still water quality problems at some monitoring sites (Kanto, Chubu, Kinki and Kyushu regions). A positive relationship between observed yearly discharge and suspended sediment load was found. Land use maps with 100 meter spatial resolution were used to apply an empirical model and develop a regression model for estimating annual suspended sediment loads directly from land use and hydrologic data. Rivers were assigned to three groups according to statistical cluster analysis of suspended sediment (SS) concentration. The correlation between the simulation result from the empirical model and the observed data had R(2) values of 0.62 and 0.71 for groups 2 and 3, and the correlation between the simulation result from the regression model and the observed data had R(2) values of 0.48 and 0.34 for groups 2 and 3. Results show that the proposed simulation technique can be used to predict the pollutant loads to river basins in Japan. Results also suggest prioritization methods and strategies that policy-makers can use to address suspended sediment pollution in rivers and water quality management in general. PMID:23563480

Luo, Pingping; He, Bin; Chaffe, Pedro Luiz Borges; Nover, Daniel; Takara, Kaoru; Mohd Remy Rozainy, M A Z

2013-05-01

39

Emission of sulfur from Lake Ontario sediments  

Microsoft Academic Search

Calculations indicate that about 6.0 x 10⁵ kg of sulfur is released annually from Lake Ontario sediments. This constitutes about 1% of the annual sulfur input into the sediments and is insignificant compared to the total sulfur that cycles annually through the lake. The sulfur released from the sediments is enriched in ³²S with the result that the sulfur in

J. O. Nriagu; R. D. Coker

1976-01-01

40

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

41

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

2009-10-22

42

Estimates of total polychlorinated biphenyl (PCB) compounds in soils/sediments by hydrogenolysis to dicyclohexyl.  

PubMed

A method to determine the total PCB content by hydrogenolysis (hydrodechlorination and hydrogenation) of chlorinated biphenyl compounds was extended to natural particulate matrices (soil and sediment). The contaminated soil was suspended in hexane in the presence of Pd/gamma-Al2O3 in a hydrogen atmosphere then permitted to react for one hour at 65 degrees C. Dicyclohexyl, recovered in the hexane, was quantified by gas chromatography mass spectrometry. The reaction was very efficient for soil/sediment in hexane suspension and virtually complete provided that excess catalyst was added to samples that were burdened with higher PCB loadings prior to reaction otherwise some partial hydrogenation of biphenyl was also observed. The proposed method was validated with the analysis of five certified reference materials. PMID:12948242

Ehsan, Sadia; Prasher, S O; Marshall, W D

2003-08-01

43

Distribution of total mercury in surface sediments of the western Jade Bay, Lower Saxonian Wadden Sea, southern North Sea.  

PubMed

A total of 114 surface sediment samples was equidistantly collected in the western part of the Jade Bay, southern North Sea, to analyse total mercury contents as well as grain size distribution and total organic carbon (TOC) contents. Total mercury was determined by oxygen combustion-gold amalgamation. Validation, precision and accuracy of the method were evaluated and controlled with two certified reference materials (HISS-1 and MESS-3). Total mercury contents varied between 8 and 243 ng/g dry sediment with a mean value of 103 ng/g dw. The mercury levels in surface sediments showed an inhomogeneous spatial distribution with higher contents in near-dike areas. The values are mostly in the range of natural background values (50–100 ng/g dw) and positively related to TOC and clay/silt contents (<63 ?m). The present total mercury contents are compared to those of previous studies, in order to estimate possible temporal trends of mercury contents in the study area over the last decades. Moreover, the comparison to sediment quality guidelines indicated that the surface sediments of the Jade Bay are not mercury contaminated. These results also suggested that the current mercury contents of Jade Bay surficial sediments are mostly affected by atmospheric deposition and re-emission. PMID:22301998

Jin, Huafang; Liebezeit, Gerd; Ziehe, Daniel

2012-04-01

44

Influence of different temporal sampling strategies on estimating total phosphorus and suspended sediment concentration and transport in small streams  

USGS Publications Warehouse

Various temporal sampling strategies are used to monitor water quality in small streams. To determine how various strategies influence the estimated water quality, frequently collected water quality data from eight small streams (14 to 110 km2) in Wisconsin were systematically subsampled to simulate typically used strategies. These subsets of data were then used to estimate mean, median, and maximum concentrations, and with continuous daily flows used to estimate annual loads (using the regression method) and volumetrically weighted mean concentrations. For each strategy, accuracy and precision in each summary statistic were evaluated by comparison with concentrations and loads of total phosphorus and suspended sediment estimated from all available data. The most effective sampling strategy depends on the statistic of interest and study duration. For mean and median concentrations, the most frequent fixed period sampling economically feasible is best. For maximum concentrations, any strategy with samples at or prior to peak flow is best. The best sampling strategy to estimate loads depends on the study duration. For one-year studies, fixed period monthly sampling supplemented with storm chasing was best, even though loads were overestimated by 25 to 50 percent. For two to three-year load studies and estimating volumetrically weighted mean concentrations, fixed period semimonthly sampling was best.

Robertson, D. M.

2003-01-01

45

Siberian regional climate change recorded in annually-laminated lake sediments (Lake Shira, Khakassia, Lake Kucherla, Altai)  

NASA Astrophysics Data System (ADS)

During field work in 2009 were sampled cores of bottom sediments of Lake Shira (Khakassia) and Lake Kucherla (Altai). Sediments contain annually laminated layers (varves). The average thickness of layers in the Lake Shira sediments is 1.3 mm, in the Lake Kucherla sediments - 2.3 mm. Cores were impregnated with epoxy resin and then are prepared solid samples thickness of 2 mm for X-ray scan. X-ray scanning was carried out in the Siberian Synchrotron Radiation Center (Budker Institute of nuclear physics SB RAS, Novosibirsk) using the excitation energies of 18 and 24 keV by the methods described in papers [1, 2]. Scanning X-ray fluorescence analysis on synchrotron radiation (SR-XRFA) as a high-efficiency method of microelement analysis is adapted to determine more than 35 elements with minimal step 0.1 mm. A detailed study of the varves with a spatial resolution of 100 microns showed seasonal variation of trace-element composition within the annual layers. It was counting the number of annual layers using the geochemical variations of sediment. Key geochemical indicators of terrigenous (Ti, Ga, Rb, Sr, Zr) and organogenic (Zn, Br, U) components of sediments were identified. Comparison of meteorological data for the past 50 years with the lithological and geochemical parameters of sediments showed a stable dependence of trace-element composition of sediments with the climate variation in the region. Investigated lakes contain high-resolution records of regional climate changes. [1] K.V. Zolotarev et all. Nucl. Instrum. and Meth. A470 (2001),376. [2] A.V. Daryin et all. Nucl. Instrum. and Meth. A 543 (2005) 255.

Darin, Andrey; Kalugin, Ivan; Maksimova, Natalya; Ovchinikov, Dmitrii; Rakshun, Yiakov

2010-05-01

46

Annually resolved lake and shallow marine sediment records of global climate change of the past 16,000 years  

Microsoft Academic Search

In the sediments of lake Huguang Maar in coastal southeast China, the titanium content and redox-sensitive magnetic properties record the strength of winter monsoon winds at subdecadal to annual resolution over the last 16 thousand years. The record indicates a stronger winter monsoon prior to the Bølling-Allerød warming, during the Younger Dryas, and during the middle and late Holocene, when

G. H. Haug; A. Brauer; G. Yancheva; P. Dulski; J. F. Negendank; L. C. Peterson; D. M. Sigman

2007-01-01

47

Six centuries of annually resolved 10Be in varved lake sediments and its relation to production rates  

NASA Astrophysics Data System (ADS)

A relatively short atmospheric residence time of a few months to one year, combined with a simple chemistry with only one charge state and a lack of anthropogenic sources, has made 10Be a vital source of information about past variability in solar activity, cosmic rays and geomagnetic field intensity. Because these forces affect the cosmogenic isotope production rate, past variations can be traced and timed by measuring 10Be in well-dated archives, among which are ice and sediment cores. Annually resolved terrestrial 10Be archives other than polar ice sheets are a hereto unexplored source of past solar activity and climate information, the main impediment being difficulties in finding natural archives that allow for annual sampling with sufficient 10Be for AMS (accelerator mass spectrometry) measurements. Cosmogenic isotope production is geographically unevenly distributed, and despite subsequent atmospheric mixing, atmospheric circulation patterns and deposition pathways may cause local or regional variations of 10Be deposition. Although ice cores from Greenland and Antarctica have provided interesting data, a lack of annually resolved 10Be data from sediment archives represents a hindrance against exploring the nature of 10Be signals in regions other than polar. Varved lake sediments are potential targets for this purpose, with sufficient temporal resolution to reveal whether the sediment 10Be signal reflects production variations driven by the 11-year Schwabe solar cycle, or whether it is more controlled by local catchment parameters on this timescale. Here we report for the first time annual distribution of 10Be in varved sediments, from a lake situated at 63.6° N, 29.1° E, 96 m a.s.l. The focus on the last 600 years provides an unprecedented opportunity for comparison of sediment 10Be data with annual ice core, neutron monitor and sunspot number data. The results indicate successful recovery of 10Be atoms from as little as 20 mg sediment, with average concentrations of 4×108 atoms g-1. Deposition rates were determined using sediment accumulation rates and the size of the catchment area, and the range of 0.6-3.5×106 atoms cm-2 a-1 agrees with modelled values in literature and earlier lake sediment findings. Several periods of raised 10Be deposition were identified and can be matched to periods of low solar activity, such as during the Maunder and Spörer grand solar minima. We observe relatively high 10Be values during some years, a variability which has also been recognized in ice core 10Be records. This may relate to atmospheric transport and deposition processes, but in our case peaks may also indicate infrequent pulses of 10Be from the catchment area.

Berggren, Ann-Marie; Aldahan, Ala; Possnert, Göran; Haltia-Hovi, Eeva; Saarinen, Timo

2010-05-01

48

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

49

Phytoremediation in mangrove sediments impacted by persistent total petroleum hydrocarbons (TPH's) using Avicennia schaueriana.  

PubMed

This study evaluated the efficiency of Avicennia schaueriana in the implementation of phytoremediation compared with intrinsic bioremediation in mangrove sediments contaminated by total petroleum hydrocarbons (TPHs). The experiment was conducted for 3months at a pilot scale under conditions similar to a mangrove: the dynamics of the tides were simulated, and physical, chemical, microbiological and biogeochemical parameters were monitored. After the 90 days, it was found that the phytoremediation was more efficient in the degradation of the TPHs compared to bioremediation, reducing the initial concentration of 32.2-4.2 mg/g. A. schaueriana was also more efficient in mediating the degradation of different fractions of hydrocarbons, achieving a removal efficiency of 87%. The microbiological results consisted of a higher growth in the model with the plants, demonstrating the phytostimulation ability of the plants. Finally, the experiment showed that phytoremediation is a promising alternative in mangrove impacted by oil. PMID:23228519

Moreira, Icaro T A; Oliveira, Olivia M C; Triguis, Jorge A; Queiroz, Antonio F S; Ferreira, Sergio L C; Martins, Cintia M S; Silva, Ana C M; Falcão, Brunno A

2012-12-08

50

TOTAL MERCURY AND METHYLMERCURY IN SEDIMENTS AND IN THE POLYCHAETE NEREIS DIVERSICOLOR AT GROOT BUITENSCHOOR (SCHELDT ESTUARY, BELGIUM)  

Microsoft Academic Search

Total mercury (Hg) and methylmercury (MeHg) concentrations were determined in sediments and in the polychaete worm Nereis diversicolor at 13 stations of a brackish water intertidal mudflat of the Scheldt estuary. Hg and MeHg concentrations in sediments ranged from 144 to 1192 ng g-1 dw and from 0.8 to 6 ng g-1 dw, respectively. Both Hg and MeHg concentrations increased

B. B. M. MUHAYA; M. LEERMAKERS; W. BAEYENS

1997-01-01

51

Mercury speciation and total organic carbon in marine sediments along the Mediterranean coast of Israel.  

PubMed

Along the Israeli Mediterranean Coast, three areas are considered "hot spots" of mercury (Hg) pollution: (1) Northern Haifa Bay (NHB), (2) the lower Qishon River at the southern part of Haifa Bay, and (3) a marine outfall of activated sewage sludge at the southern coast off Palmachim (sewage-sludge disposal site [SDS]). Even though the total Hg (HgT) concentrations in the sediments at the three areas are of the same order of magnitude (250-500 ?g kg(-1)), Hg was shown to bioaccumulate in fish and benthic fauna from Haifa Bay but not in benthic fauna or in commercial fish caught along the southern Mediterranean Coast of Israel near the SDS outfall. The primary goal of this study was to measure the concentrations of Hg species (HgT, methyl-Hg [MeHg], and Hg in different biogeochemical fractions)-in conjunction with organic carbon-in sediments of NHB and the lower Qishon River to assess its impact on Hg transitions among the species as characterized by different bioavailability and bioaccessibility. HgT concentrations in NHB and the Qishon River ranged from 249 to 347 and 165 to 667 ?g kg(-1), respectively. MeHg was significantly higher in the Qishon River (6.3-34.0 ?g kg(-1)) than in NHB (0.22-0.70 ?g kg(-1)) as were total organic carbon (TOC) concentrations (average 2.5 vs. 0.13 %). The relative Hg distribution in the biogeochemical fractions in NHB was 2.3 % in the most bioaccessible fractions (F1 + F2), 55 % in the organo-chelated species fraction (F3), 42 % in the strong-complexed species fraction (F4), and 0.7 % in the mercuric-sulfide fraction (F5). In the Qishon River, the bioavailable F1 + F2 and F3 fractions were lower than in NHB (<0.01 and 23 %, respectively) and the more refractory F4 and F5 fractions higher (73 and 3.3 %, respectively). The fractionation of Hg in Qishon River sediments was similar to the distribution found in polluted stations at the SDS. TOC and MeHg were positively and negatively correlated, respectively, in Qishon River and NHB sediments. Methylation depended on TOC availability when its concentration was in the range of 2-4 wt%. It is possible that TOC in the sediment controlled Hg speciation: Hg in F3 decreased and in F4 increased with increasing TOC concentrations. In contrast, MeHg/HgT was significantly positively correlated with TOC and Hg in the stable F4 fraction and negatively correlated with Hg in the F3 fraction. It was therefore assumed that higher TOC concentrations enhanced microbial activity and decomposition of organic matter. Hg was released from the F3 fraction and was either transferred to the F4 fraction or made available for methylation processes. PMID:22961217

Shoham-Frider, Efrat; Azran, Shlomi; Kress, Nurit

2012-09-09

52

Environmental response to volcanic events based on annually laminated sediments from Lake Van, Turkey  

NASA Astrophysics Data System (ADS)

High resolution palynology of lake sediments provides not only a tool to detect short-term climate fluctuations or anthropogenic impacts, but also to study rapid environmental change through catastrophic events. Numerous studies have dealt with vegetation disturbance from recent volcanic events; however, only few prehistoric volcanic events and their impact on the surrounding vegetation have been the focus of palynological investigations. Here we present new results of high resolution pollen studies from Lake Van, one of the largest alkaline lakes in the world. The lake is situated on the plateau of Eastern Anatolia (Turkey), an area of high tectonic activity. Lake Van itself is surrounded by at least three volcanic centres that have been active until the 19th century. Eastern Anatolia has a semiarid continental climate and a vegetation dominated by oak-steppe forest. Cores taken during a research campaign in 2004 consist of annually laminated sediments covering the Holocene and Weichselian Late Glacial. The cores contain 16 tephra layers that document the volcanic history of the area. High resolution (< 5 years/sample) palynological investigations indicate large-scale vegetation disturbances caused by a Late Holocene volcanic eruption and also illustrate the process of recovery of the forest steppe vegetation. Statistical analysis of the pollen data show clear correlations between tephra thickness, tephra provenance, and vegetation disturbance. Although the Lake Van basin has a long history of human inhabitation, particularly in the Middle Iron Age when it was centre of the Urartian Kingdom, in view of our preliminary results, a volcanic impact on human activities in the Lake Van area has not been detected.

Riedel, Nils; Litt, Thomas

2010-05-01

53

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

54

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

55

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...

56

Sediment-adsorbed total mercury flux through Yolo Bypass, the primary floodway and wetland in the Sacramento Valley, California.  

PubMed

The fate and transport of mercury are of critical concern in lowland floodplains and wetlands worldwide, especially those with a history of upstream mining that increases the mobility of both dissolved and sediment-bound Hg in watersheds. A mass budget of total mercury (THg) quantifies sources and storage for particular areas - knowledge that is required for understanding of management options in lowland floodplains. In order to assess contaminant risk in the largest flood-control bypass, prime wetland, and restoration target in the Sacramento River basin, we estimated empirical relationships between THg, suspended sediment concentration (SSC), and streamflow (Q) for each of the major inputs and outputs using data from various publicly available sources. These relationships were improved by incorporating statistical representations of the dynamics of seasonal and intra-flood exhaustion (hysteresis) of sediment and mercury. Using continuous records of Q to estimate SSC suspended sediment flux and SSC to estimate THg flux, we computed the net transfer of sediment-adsorbed mercury through the Yolo Bypass over a decade, 1993-2003. Flood control weirs spilling Sacramento River floodwaters into the bypass deliver ~75% of the water and ~50% of the river's suspended sediment load, while one Coast Range tributary of the bypass, Cache Creek, contributes twice the THg load of the mainstem Sacramento. Although estimated sediment flux entering Yolo Bypass is balanced by efflux to the Sacramento/San Francisco Bay-Delta, there is much evidence of deposition and remobilization of sediment in Yolo Bypass during flooding. These factors point to the importance of the bypass as sedimentary reservoir and as an evolving substrate for biogeochemical processing of heavy metals. The estimates of mercury flux suggest net deposition of ~500 kg in the 24,000 ha floodway over a decade, dominated by two large floods, representing a storage reservoir for this important contaminant. PMID:22078330

Springborn, Michael; Singer, Michael Bliss; Dunne, Thomas

2011-11-09

57

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

58

DIATOM INDICATORS OF TOTAL PHOSPHORUS, SEDIMENTS, AND WATERSHED FOREST COVER IN LAKE MICHIGAN COASTAL, RIVERINE WETLANDS  

EPA Science Inventory

Diatom assemblages are being investigated as response and diagnostic indicators as part of our Great Lakes coastal wetlands research designed to support the development of nutrient, habitat, and sediment criteria and to develop community- and landscape-level diagnostic indicator ...

59

Toxic elements at a disused mine district: Particle size distribution and total concentration in stream sediments and mine tailings.  

PubMed

Heavy metal and metalloid pollution at a disused pyrite mine was investigated. Five solid samples collected in the area (three stream sediments with different soil texture, a background soil sample and a mine tailing) were characterised by mineral and element composition, particle size distribution (by wet and dry sieving and laser diffraction) and total concentration by acid digestion (Mn, Zn, Cu, Pb, Hg, Cd, Sb and As). X-ray and element analyses denoted a common mineralogical and chemical composition of mainly quartz, clinochlore, muscovite, anorthite, and hematite. Particle size distributions of the five samples showed that stream sediments were characterised by larger percentage of sand range classes (2000-60 microm) while background sample and tailing are mainly characterised by gravel particles (>2000 microm). Wet and dry sieving procedures gave different particle size distributions, which can be interpreted by laser diffraction analysis and represented by Rosin-Rammler model. Concentrations of Zn, Cu and Cd were higher in the stream sediments than the tailing and background soil, while Mn, As, Sb and Hg are mainly concentrated in the tailing sample. Metal concentrations in the three stream sediment samples are correlated with both particle size dimensions (D(63.2)) and concentration of geochemical normalizers (iron and aluminium). These correlations are observed also for the pollutants that are mainly concentrated in tailing sample (Mn and As), denoting the importance of surface interactions also for the binding of these elements onto stream sediments. PMID:17400373

Giuliano, V; Pagnanelli, F; Bornoroni, L; Toro, L; Abbruzzese, C

2007-03-03

60

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

61

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

62

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

63

Geospatial analysis of spatiotemporal patterns of pH, total suspended sediment and chlorophyll- a on the Amazon floodplain  

Microsoft Academic Search

We applied spatial data analysis and geostatistical procedures to pH, total suspended sediment and chlorophyll-a concentration data gathered on an Amazon floodplain lake. Variographic analysis and ordinary kriging interpolation were used\\u000a to identify and describe spatiotemporal patterns of variability in these parameters, which are relevant to understand the\\u000a dynamics of water circulation on the floodplain lake. In spite of the

Cláudio Clemente Faria Barbosa; Evlyn Márcia Leão de Moraes Novo; John M. Melack; Mary Gastil-Buhl; Waterloo Pereira Filho

2010-01-01

64

Monitoring Fine Sediment; Grande Ronde and John Day Rivers, 1998 Annual Report.  

SciTech Connect

Fine sediment levels in spawning substrate have a major effect on salmon survival from egg to smolt. Assessments have consistently concluded that fine sediment is a major problem for salmon in the Grande Ronde and, to a lesser extent, the John Day rivers. It is likely that fine sediment levels in these rivers must be reduced if salmon survival from egg to smolt is to be increased.

Purser, Michael D.; Rhodes, Jonathan J.

1999-01-01

65

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...

66

Total mercury loadings in sediment from gold mining and conservation areas in Guyana.  

PubMed

The Low Carbon Development Strategy proposed in June 2009 by the government of Guyana in response to the Reducing Emissions from Deforestation and Forest Degradation in Developing Countries program has triggered evaluation of forest-related activities, thereby acting as a catalyst for improvements in Guyana's small- to medium-scale gold mining industry. This has also shed light on areas committed to conservation, something that has also been handled by Non Governmental Organizations. This paper compares water quality and mercury concentrations in sediment from four main areas in Guyana, two that are heavily mined for gold using mercury amalgamation methods (Arakaka and Mahdia) and two that are considered conservation areas (Iwokrama and Konashen). Fifty-three sediment and soil mercury loadings ranged from 29 to 1,200 ng/g and averaged 215 ± 187 ng/g for all sites with similar averages in conservation and mining areas. Sediment loadings are within the range seen in French Guiana and Suriname, but conservation area samples had higher loadings than the corresponding uncontaminated baselines. Type of ore and location in the mining process seemed to influence mercury loadings. Mercury sediment loadings were slightly positively correlated with pH (correlation coefficient = 0.2; p value < 0.001) whereas no significant correlations were found with dissolved oxygen or turbidity. PMID:21076999

Howard, Joniqua; Trotz, Maya A; Thomas, Ken; Omisca, Erlande; Chiu, Hong Ting; Halfhide, Trina; Akiwumi, Fenda; Michael, Ryan; Stuart, Amy L

2010-11-16

67

Radon loss from encapsulated sediments in Ge gamma-ray spectrometry for the annual radiation dose determination in luminescence dating  

NASA Astrophysics Data System (ADS)

In Ge gamma-ray spectrometry for the annual radiation dose determination in the luminescence dating of sediments, the picture of 226Ra enrichment or depletion (in the 238U decay series) obtained via measurement of its 214Pb and 214Bi daughters may be disturbed by the 222Rn-content of the sample being decreased due to manipulations such as drying and pulverizing. Therefore, it is common practice to start the measurement only about 1 month after encapsulating the material, after which the 226Ra(1600 a)- 222Rn(3.82 d) mother-daughter equilibrium is re-established. Evidently, this only holds on condition that no significant escape of Rn occurs out of the sediment after making it up for counting. In order to experimentally investigate this effect, in the present work measurements were carried out with various types of dried and pulverized sediments that were either encapsulated in screw-cap polystyrene vials or in sealed glass containers, or that were mixed with molten wax followed by solidification in a cylindrical geometry. From the results obtained, it could be concluded that preparation and counting of the sediment-wax mixture is the method of choice.

de Corte, F.; Vandenberghe, D.; de Wispelaere, A.; Buylaert, J.-P.; van den Haute, P.

2006-01-01

68

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

69

Bacterial numbers and growth in surficial deep-sea sediments and phytodetritus in the NE Atlantic: Relationships with particulate organic carbon and total nitrogen  

Microsoft Academic Search

Bacteria in deep-sea sediments constitute the largest global fraction of total benthic bacteria, and play a major role in most biogeochemical cycles. However, as yet the relationship between bacterial production and substrate availability (particulate organic carbon and nitrogen) in deep-sea sediments is not well understood. Therefore the aim of this study was to explore the relationships between bacterial numbers and

C. M. Turley; J. L. Dixon

2002-01-01

70

Millenial long near-annual summer temperature reconstruction from abiotic sediment characterstics of varved Lake Silvaplana (eastern Swiss Alps)  

NASA Astrophysics Data System (ADS)

In this study we present a summer temperature reconstruction based on multiple geochemical and sedimentological climate proxies from annually laminated Lake Silvaplana (eastern Swiss Alps), covering the last millennium. These proxies, including mass accumulation rate, biogenic silica flux, XRD peak intensity ratios and in situ reflectance spectroscopy reflect summer temperature. Individually they show excellent calibration statistics on subdecadal time scales (Blass et al. 2007, Trachsel et al. 2008) and compare well with alpine tree-ring reconstructions and climate field reconstructions. The combined response of the proxies to climate state variables was assessed using redundancy analysis (RDA). After evaluating different regression and calibration models such as principle components regression, ordinary least squares regression and partial least squares regression the most parsimonious model was used to infer summer temperature. Our multi-proxy reconstruction does not show a distinct summer temperature cooling during Little Ice Age, whereas a climate amelioration was reconstructed during medieval times. References: Blass, A., Grosjean, M., Troxler, A., and Sturm, M. (2007). How stable are twentieth-century calibration models? A high-resolution summer temperature reconstruction for the eastern Swiss Alps back to AD 1580 derived from proglacial varved sediments. The Holocene. Trachsel, M., Eggenberger, U., Grosjean, M., Blass, A., and Sturm, M. (2008). Mineralogy-based quantitative precipitation and temperature reconstructions from annually laminated lake sediments (Swiss Alps) since AD 1580. Geoph. Res. Let.

Trachsel, M.; Kamenik, C.; Grosjean, M.; Larocque, I.; Blass, A.; Sturm, M.

2009-04-01

71

Geochemical signature of contaminated sediment remobilization revealed by spatially resolved X-ray microanalysis of annual rings of Salix nigra.  

PubMed

An X-ray microprobe was used to determine the concentration and distribution of Ni, U, and other metals within annual rings of willows (Salix nigra L.) from a former de facto radiological settling basin (Steed Pond; SP) and a depositional environment downstream (Tims Branch; TB) on the Savannah River Site (SRS). Geochemical and historical information about both areas are well documented. Following spillway breaches at SP in 1984 and the early 1990s, TB is inundated with contaminated sediments during storms. Bulk elemental composition of tree cores was determined using ICP-OES. Synchrotron X-rayfluorescence (SXRF) analysis showed that the metal contents of SP and TB cores were an order of magnitude higher than those from a reference site. TB cores were enriched with Ni in 1984 and 1991, corresponding with SP spillway breaches (containing 790 mg kg(-1) Ni in 1991). Cores from SP exhibited an extremely high Ni peak in 1996, approximately 5000 mg kg(-1), even though contaminant levels at SP did not change. The geochemical signature of contaminants recorded in TB annual rings reflected the significant sediment remobilization events consistent with the detailed history of the site, and at concentrations relative to their proximity to the source term. However, physiological processes occurring within impacted trees strongly influence the chronological accuracy of dendroanalysis and must be investigated further. PMID:12775047

Punshon, Tracy; Bertsch, Paul M; Lanzirotti, Antonio; McLeod, Ken; Burger, Joanna

2003-05-01

72

78 FR 59791 - Annual Company-Run Stress Tests at Banking Organizations With Total Consolidated Assets of More...  

Federal Register 2010, 2011, 2012, 2013

...7100 AE 02] Annual Company-Run Stress Tests at Banking Organizations With Total Consolidated...Capital Framework for 2013-2014 Stress Test Cycle AGENCY: Board of Governors of the...revised capital framework) in their stress tests for the stress test cycle that begins...

2013-09-30

73

12 CFR Appendix L to Part 226 - Assumed Loan Periods for Computations of Total Annual Loan Cost Rates  

Code of Federal Regulations, 2013 CFR

...Periods for Computations of Total Annual Loan Cost Rates L Appendix L to Part 226 Banks and Banking FEDERAL RESERVE SYSTEM... TRUTH IN LENDING (REGULATION Z) Pt. 226, App. L Appendix L to Part 226âAssumed Loan Periods for...

2013-01-01

74

12 CFR Appendix L to Part 1026 - Assumed Loan Periods for Computations of Total Annual Loan Cost Rates  

Code of Federal Regulations, 2013 CFR

...Periods for Computations of Total Annual Loan Cost Rates L Appendix L to Part 1026 Banks and Banking BUREAU OF CONSUMER FINANCIAL... TRUTH IN LENDING (REGULATION Z) Pt. 1026, App. L Appendix L to Part 1026âAssumed Loan Periods for...

2013-01-01

75

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

Federal Register 2010, 2011, 2012, 2013

...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

76

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

77

Total Maximum Daily Load Metals and Sediment Glanraffan Creek Watershed Montgomery County, Pennsylvania.  

National Technical Information Service (NTIS)

The report presents the Total Maximum Daily Loads (TMDLs) developed for stream segments in the Glanraffan Creek Watershed. These were done to address the water quality impairments noted on the 1996 Pennsylvania Section 303(d) list of impaired waters, requ...

2003-01-01

78

Estimating annual generation rates of total P and total N for different land uses in Tasmania, Australia.  

PubMed

Water quality issues have become increasingly important to Australian catchment stakeholders. As extensive nutrient sampling and modelling expertise are often absent or unattainable, simple unit-area models like Catchment Management Support System (CMSS) remain an attractive option for informing water quality management decisions. The selection of nutrient generation rates for use in CMSS is often an arbitrary assignment based on limited literature sources or expert opinion. Using a Bayesian model to estimate nutrient generation rates for the region of Tasmania, Australia, improved the rigor of CMSS modelling and in the process highlighted that dairy pastures were the most significant contributor of total phosphorus and total nitrogen loads to Tasmanian rivers. PMID:21354692

Broad, S T; Corkrey, R

2011-02-26

79

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...

80

Annual Particle Flux and a Winter Outburst of Sedimentation in the Northern Norwegian Sea,  

National Technical Information Service (NTIS)

Monthly samples were collected by a sediment trap deployed for one year at 473 m above sea floor in water 2123 m deep at a station located at 75 N, 11 E, southwest of Spitsbergen. This station was positioned at the northernmost extension of the Norwegian ...

S. Honjo S. J. Manganini G. Wefer

1988-01-01

81

Annual and decadal variation of sediment yield in Australia, and some global comparisons  

Microsoft Academic Search

An analysis of 275 estimated sediment yields from Australia shows that regional differences of yield correlate with different variables for different sizes of drainage basin. Despite this scale-dependence, high yields in large streams appear to be the result of high delivery rates from uplands, controlled substantially by rainfall and runoff energy, and the nature of drainage networks. Land use plays

R. J. WASSON

1994-01-01

82

Levels of total mercury in different fish species and sediments from the Upper Volta Basin at Yeji in Ghana.  

PubMed

In this study, total mercury concentrations were determined in sediments and seven different fish species from the Upper Volta Basin area of Yeji in Ghana. Mercury concentrations found ranged from 44.17 to 85.88 ng/g wet weight for Synodontis gambiesis, from 11.25 to 79.73 ng/g wet weight for Synodontis membranaceus, from 13.11 to 38.64 ng/g wet weight for Synodontis ocellifer, from 16.39 to 25.82 ng/g wet weight for Distishodus rotratus, from 40.80 to 90.30 ng/g wet weight for Bagrus docmac, from 10.48 to 61.90 ng/g wet weight for Chrysichthys nigrodigitatus and from 12.33 to 24.18 ng/g wet weight for Gnathoneus senegalensis. These values are below the 500 ng/g guideline recommended by the WHO/FAO, implying that fish from the Upper Volta Basin area of Yeji are safe for human consumption. Good correlation was observed between mercury concentration and fresh weight (R(2) = 0.6067) and total length (R(2) = 0.8754) for Gnathonemus senegalensis. However, poor correlations were observed between mercury concentration and fresh weight and total length for the other six species. Mercury in sediments ranged from 11.87 to 70.25 ng/g dry weights with a mean of 41.60 ng/g dry weight being below the IAEA threshold of 810 ng/g.. These values show that sections of the Upper Volta River remain relatively clean in spite of substantial loadings of mercury into the river's basin from gold mining activities. PMID:21318735

Kwaansa-Ansah, E E; Agorku, S E; Nriagu, J O

2011-02-13

83

Annually-layered lake sediments reveal strongly increased release of persistent chemicals due to accelerated glacier melting  

NASA Astrophysics Data System (ADS)

Melting glaciers may represent a secondary source of chemical pollutants that have previously been incorporated and stored in the ice. Of particular concern are persistent organic pollutants (POPs), such as the insecticide dichlorodiphenyl trichloroethane (DDT) and industrial chemicals like polychlorinated biphenyls (PCBs), which are hazardous environmental contaminants due to their persistent, bioaccumulative and toxic properties. They were introduced in the 1930s and eventually banned in the 1970s. After release into the environment these chemicals were atmospherically transported to even remote areas such as the Alps and were deposited and stored in glaciers. Ongoing drastic glacier melting due to global warming, which is expected to further accelerate, implies the significance of studying the fate of these 'legacy pollutants'. Proglacial lake sediments provide well-dated and high-resolution archives to reconstruct timing and quantities of such a potentially hazardous remobilization. The goal of this study is to reconstruct the historical inputs of POPs into remote alpine lakes and to investigate the accelerated release of POPs from melting glaciers. Due to their lipophilic character, these chemicals exhibit a high tendency to adsorb to particles whereas concentrations in water are expected to be low. Therefore, quantitative determination in annually-layered lake sediment provides an excellent way to investigate the temporal trend of inputs into lakes that act as particle sinks. For this purpose, sediment cores were sampled from proglacial lakes in the Bernese Alps (Switzerland), which are exclusively fed by glacial melt waters. For comparison, cores were also taken from nearby high-alpine lakes located in non-glaciated catchments, which only should record the initial atmospheric fall-out. Sediment layers were dated by annual varve counting and radionuclide measurements; they cover the time period from the mid 20th century to today. The measured time series of POPs indicate indeed different patterns in proglacial and non-glacial lakes. Similar to lowland Swiss plateau lakes [1,2], high-alpine lakes show a historic maximum of POP-concentrations some decades ago, which is synchronous with their primary use at that time. However, only proglacial lakes exhibit a dramatic re-increase in POP-input during the last years, thus confirming the crucial role of glaciers as reservoir and secondary source of these pollutants. The burden of pollutants in these sediments due to glacier melting is already in the same range as the earlier accumulations from direct atmospheric fall-out. Furthermore, the undiminished increase of the fluxes of many POPs into the sediment of proglacial lakes does not yet indicate an exhaust of the glacial inventory of these contaminants. Considering ongoing global warming and accelerated massive glacier melting predicted for the future, our study indicates the potential for significant environmental hazards due to pollutants delivered into such remote mountainous areas. [3] [1] Zennegg M. et al., Chemosphere 2007, 67, 1754. [2] Bogdal C. et al., Env. Sci. & Technol. 2008, 47, 6817. [3] Bogdal C. et al., Env. Sci. & Technol. 2009, 43, 8173.

Anselmetti, Flavio S.; Blüthgen, Nancy; Bogdal, Christian; Schmid, Peter

2010-05-01

84

High-resolution past environmental reconstruction in East Asia using annually laminated lake sediments of Lake Megata in northeastern Japan  

NASA Astrophysics Data System (ADS)

37 m-long non-glacial varved sequences were taken from Ichi-no-Megata maar in Oga Peninsula, Akita, northern part of Japan. Ichi-no-Megata maar occupies 0.25 km2 with a maximum water depth of ca. 45.1 m. The shape of lake is a kettle-type basin and the deepest bottom basin is very flat. We took core samples (named IMG06 core) at the center of the lake in November to December in 2006. In order to take completely continuous maar sediment, we drilled three holes and take every sample from each hole which apart only few meters. In this drilling campaign, we can 37 m-long continuous maar sediment except thick volcanic deposits from 26.5 to 31.7m in core. The sedimentological feature of IMG06 core is dominated by thin lamination clay/silt from most top part up to 37 m with turbidites characterized upward fining structure. The SEM image observation of lamination reveals that sponge-like lamina consists of diatom assemblage against dark colored lamina consists of mixture of detritus minerals, clay minerals, and diatom. It means sponge-like lamina deposits during spring season, and later one deposits during another three seasons, and then these thin lamination of IMG06 core could be identified as annual lamination (varves). This interpretation is supported by the correlation of historic event as earthquake and tunnel construction. In this IMG06 core, six volcanic ashes are found and we have also analyzed radiocarbon dating from 38 horizons of the core to use leaf and seeds inter-bedded varves. As the results, the IMG06 core covers from 25,000 to 4,000 14C yr BP with stable sedimentation rates (0.71mm/year).

Yamada, K.; Gotanda, K.; Yonenobu, H.; Shinozuka, Y.; Kitagawa, J.; Makohonienko, M.; Schwab, M.; Haraguchi, T.; Yasuda, Y.

2007-12-01

85

Denitrification activity is closely linked to the total ambient Fe concentration in mangrove sediments of Goa, India  

NASA Astrophysics Data System (ADS)

Denitrification activity (DNT) and associated environmental parameters were examined in two mangrove ecosystems of Goa, India - the relatively unimpacted Tuvem and the anthropogenically-influenced Divar. Sampling was carried out at every 2 cm interval within the 0-10 cm depth range to determine (1) seasonal (pre-monsoon, monsoon and post-monsoon) down-core variation in DNT (2) assess the environmental factors influencing the DNT and (3) to build predictive models for benthic DNT. Denitrification generally decreased with depth and showed marked seasonal variation at both the locations. Denitrification peaked during the pre-monsoon occurring at a rate of up to 21.00 ± 12.84 nmol N2O g-1 h-1 within 0-4 cm at both the locations. Further, DNT at pre-monsoon was significantly influenced by Fe content at Tuvem and Divar suggesting Fe-mediated nitrate respiration. The influence of other limiting substrates such as NO3- and NO2- was most important during the monsoon and post-monsoon especially at Divar. The multiple regression models developed could predict 67-98% of the observed variability in DNT through the seasons. About 6-9 environmental variables were required to relatively well-predict DNT in these sediments with the complexity governing DNT decreasing from pre-monsoon to post-monsoon. Our results reveal that seasonal dynamics of DNT in tropical mangrove sediments are closely linked to the total Fe at the prevailing ambient concentration in both the systems.

Fernandes, Sheryl Oliveira; Gonsalves, Maria-Judith; Michotey, Valérie D.; Bonin, Patricia C.; LokaBharathi, P. A.

2013-10-01

86

Nondetrital and total metal distribution in core sediments from the U-Tapao Canal, Songkhla, Thailand  

Microsoft Academic Search

The U-Tapao Canal is the main source of freshwater draining into the outer part of Songkhla Lake, which is the most important estuarine lagoon in Thailand. Songkhla Lake is located in southern Thailand between latitudes 7°08' and 7°50' N and longitudes 100°07' and 100°37' E. Acetic acid (HOAc)-soluble Cu, Fe, Mn, Pb, and Zn and the total concentration of these

Waraporn Sirinawin; Penjai Sompongchaiyakul

2005-01-01

87

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

Microsoft Academic Search

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

T. J. Iannuzzi; R. J. Wenning

1995-01-01

88

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

Microsoft Academic Search

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

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

2005-01-01

89

Hydrographs from selected observations wells and total annual pumpage from municipal supply wells, 1950-83, Santa Fe, New Mexico  

USGS Publications Warehouse

Total annual pumpage from seven municipal supply wells for 1950-83 is depicted by a bar graph. Water-level hydrographs for 16 observation wells located throughout the Santa Fe metropolitan area are shown. The period of record for the observation wells is variable; the longest is from 1951 to 1984. All wells are located on a map of the Santa Fe area. (USGS)

Richey, Steven F.

1985-01-01

90

Mass-height profile and total mass transport of wind eroded aeolian sediments from rangelands of the Indian Thar Desert  

NASA Astrophysics Data System (ADS)

Wind erosion is an active land degradation process in the Indian Thar Desert and severe dust storm events during hot summer months in the region are very common. Assessment of soil loss due to dust storm events from major land use systems of the Indian Thar Desert is highly essential for proper environmental planning. Characterization of the mass-height profile of wind eroded aeolian sediment is an important step to compute soil loss/mass transport but was not previously studied in the region. In the present study, aeolian mass fluxes (kg m -2) at different heights from soil surface were measured at two major rangelands in the Indian Thar Desert: Overgrazing rangeland at Jaisalmer (26°55'N and 70°57'E), and controlled grazing rangeland at Chandan (27°01'N and 71°01'E). Evaluation of several mass-height profile models revealed that a power decay function [ q( z) = az-b, where q( z) is the measured mass flux at an height of z (m) from soil surface; a and b are parameters of the equation] was best to characterize the mass-height relationship of aeolian sediments from the Indian Thar Desert. The average mass transport rate (kg m -1 day -1) or the total soil loss during hot summer months was significantly higher at the overgrazed rangeland site than at the controlled grazing rangeland site. Therefore, protection of existing rangelands, which comprise about 80% geographical area of the Indian Thar Desert may check the land degradation process due to wind erosion.

Mertia, R. S.; Santra, Priyabrata; Kandpal, B. K.; Prasad, R.

2010-11-01

91

Sediment Yield Modeling in a Large Scale Drainage Basin  

Microsoft Academic Search

This paper presents the findings of spatially distributed sediment yield modeling in the upper Indus River basin. Spatial erosion rates calculated by using the Thornes model at 1-kilometre spatial resolution and monthly time scale indicate that 87 % of the annual gross erosion takes place in the three summer months. The model predicts a total annual erosion rate of 868

K. Ali; D. H. de Boer

2009-01-01

92

Effect of the 11-year cycle of solar activity on characteristics of the total ozone annual variation  

NASA Astrophysics Data System (ADS)

The goal of the paper is an analysis of changes in the amplitude and phase characteristics of the annual variation (AC) of total ozone (TO) from ground-based and satellite (TOMS) measurements and their interpretation with a two-dimensional photochemical model. According to ground-based TO measurements, two characteristic types of quasi-decadal variations in the phase of the annual harmonic (AH) of total ozone have been noted: variations in phase and antiphase with solar activity (SA). Changes in the TO AH phase opposite to solar activity variation are noted the high latitudes of the North Atlantic region and in the tropical belt, and in-phase changes are observed in the middle and subtropical latitudes of both hemispheres. Variations in the TO AH amplitude (hence, in the TO AV amplitude) and in the annual mean TO usually coincide in phase with the SA cycle. Analysis of satellite data shows that the 0-phase of the AV and the phase of the AH of the zonal mean TO at middle latitudes vary synchronously with the 11-year solar cycle. Model simulations have shown that the stratospheric ozone influx to the middle latitudes increases in the fall and winter period during a period of maximum solar activity. This dynamic mechanism accounts for up to 30% of the winter ozone increase in the ozone maximum layer in the Southern Hemisphere midlatitudes during the solar maximum as compared with the solar minimum. In the northern midlatitudes, the dynamic mechanism makes the main contribution to ozone changes during the latter half of winter under SA variations. The stratospheric ozone inflow change induced by SA variations affects the annual variation of ozone.

Gruzdev, A. N.; Brasseur, G. P.

2007-06-01

93

Sediment transport in a large impounded river: The lower Ebro, NE Iberian Peninsula  

Microsoft Academic Search

The sediment transport of the highly regulated lower Ebro River is estimated on the basis of a measuring programme carried out between 2002 and 2004. Total sediment transport, including both suspended load and bedload, was measured upstream and downstream from the Mequinenza and Riba-roja reservoirs, with special attention to the transport during floods. Annual total load upstream from the dams

Damia Vericat; Ramon J. Batalla

2006-01-01

94

Spatio-temporal changes in totally and enzymatically hydrolyzable amino acids of superficial sediments from three contrasted areas  

NASA Astrophysics Data System (ADS)

Spatio-temporal changes in totally and enzymatically hydrolyzable amino acids (THAA and EHHA) and EHAA/THAA ratios of superficial sediments were assessed during 1997 1999 in three areas (i.e., the Gulf of Lions, the Bay of Biscay, and Central Chile) differing in their primary productivity. In all three areas, and even off Central Chile where a strong El Niño event took place during 1997 1998, spatial changes were always much greater than temporal ones. The factors affecting the spatial distributions of amino acid concentrations differed among areas. In the Gulf of Lions, sediment granulometry was apparently the most important driving force of THAA, EHAA, and EHAA/THAA, and there was no marked difference between stations located on the open slope and those in submarine canyons. Conversely, in the Bay of Biscay, there were clear differences between the stations located off Cap-Breton, on the open slope, and those in the Cap-Ferret canyon; the latter two featuring lower EHAA and THAA but higher EHAA/THAA. This pattern is likely to result from the predominance of different sources of organic matter and especially from the importance of continental inputs to the Cap-Breton canyon. Off Central Chile, amino acid concentrations and ratios were both maximal around 100 m depth, probably reflecting the interaction between the primary productivity gradient and the presence of an oxygen minimum zone (OMZ) reducing the degradation of sedimentary organics. When comparing the average values collected in the three areas studied, THAA and EHAA were highest in Central Chile, intermediate in the Bay of Biscay and lowest in the Gulf of Lions. EHAA/THAA ratios were also highest in Central Chile but were lowest in the Bay of Biscay. Differences between the Gulf of Lions and the Bay of Biscay could have been affected by sampling design. In Central Chile, the use of labile organic carbon to total organic carbon (C-LOM/TOC) and EHAA/THAA as indices of organic matter lability led to very similar results. This was not the case in the Bay of Biscay. It is therefore argued that the use of C-LOM/TOC should be restricted to highly productive areas.

Grémare, Antoine; Gutiérrez, Dimitri; Anschutz, Pierre; Amouroux, Jean Michel; Deflandre, Bruno; Vétion, Gilles

2005-04-01

95

Gas hydrates in deep ocean sediments. Annual report 1 Apr 81-31 Mar 82  

SciTech Connect

The purpose of this research is to elucidate the composition, state, and origin of gas in marine sediments, with particular emphasis on gas hydrates. Gas samples from DSDP/IPOD Site 533 on the Blake Outer Ridge in the Northwest Aatlantic were obtained for molecular and isotopic analyses. Gas samples were collected from the first successful deployment of a pressure core barrel (PCB) in a hydrate region. Two of the four PCB retrievals at in situ pressures suggested the presence of small amounts of gas hydrates. Compositional and isotopic measurements of gases from several points along the pressure decline curve indicated that (1) biogenic methane was the dominant gas (2) little fractionation in C/sub 1//C/sub 2/ ratio or the C/sub 1/ carbon isotopic composition occurred as gas hydrates decomposed during pressure decline experiments; (3) the percent of C/sub 3/, i-C/sub 4/, and CO/sub 2/ degassed increased as the pressure declined; and (4) excess nitrogen was present during initial degassing. The PCB gas also contained trace amounts of saturated, acyclic, cyclic, and aromatic C/sub 5/-C/sub 14/ hydrocarbons, as well as alkenes and tetrahydrothiophenes.

Barnard, J.M.B.L.A.; Wiesenburg, D.A.; Kennicutt, M.C.

1982-06-01

96

Total body calcium analysis. Annual report, 1 November 1972--1 October 1974  

Microsoft Academic Search

A technique to quantitate total body calcium in humans is developed. ; Total body neutron irradiation is utilized to produce argon-37. The radio argon, ; which diffuses into the blood stream and is excreted through the lungs, is ; recovered from the exhaled breath and counted inside a proportional detector. ; Emphasis is placed on: (1) measurement of the rate

T. K. Lewellen; W. B. Nelp

1974-01-01

97

Assessment of total suspended sediment concentrations in Poyang Lake using HJ-1A/1B CCD imagery  

NASA Astrophysics Data System (ADS)

We explored the potential of the environment and disaster monitoring and forecasting small satellite constellations (HJ-1A/1B satellites) charge-coupled device (CCD) imagery (spatial resolution of 30 m, revisit time of 2 days) in the monitoring of total suspended sediment (TSS) concentrations in dynamic water bodies using Poyang Lake, the largest freshwater lake in China, as an example. Field surveys conducted during October 17-26, 2009 showed a wide range of TSS concentration (3-524 mg/L). Atmospheric correction was implemented using the Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) module in ENVI with the aid of aerosol information retrieved from concurrent Terra/Moderate Resolution Imaging Spectroradiometer (MODIS) surveys, which worked well at the CCD bands with relatively high reflectance. A practical exponential retrieval algorithm was created between satellite remote sensing reflectance and in-situ measured TSS concentration. The retrieved results for the whole water area matched the in-situ data well at most stations. The retrieval errors may be related to the problem of scale matching and mixed pixel. In three selected subregions of Poyang Lake, the distribution trend of retrieved TSS was consistent with that of the field investigation. It was shown that HJ-1A/1B CCD imagery can be used to estimate TSS concentrations in Poyang Lake over synoptic scales after applying an appropriate atmospheric correction method and retrieval algorithm.

Yu, Zhifeng; Chen, Xiaoling; Zhou, Bin; Tian, Liqiao; Yuan, Xiaohong; Feng, Lian

2012-03-01

98

Comparability of Suspended-Sediment Concentration and Total Suspended-Solids Data for Two Sites on the L'Anguille River, Arkansas, 2001 to 2003.  

National Technical Information Service (NTIS)

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 sq...

J. M. Galloway D. A. Evans W. R. Green

2005-01-01

99

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

100

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

101

Solar Total Energy: Large Scale Experiment, Shenandoah, Georgia Site. Annual Report, June 1978-June 1979.  

National Technical Information Service (NTIS)

A background summary and a complete description of the progress and current status of activities relative to the Cooperative Agreement for the Solar Total Energy - Large Scale Experiment at the Bleyle Knitwear Plant at Shenandoah, Georgia are presented. A...

E. J. Ney

1979-01-01

102

The large impact of gold-mining in total-Hg content in sediment of the dam lake of Petit Saut (French Guiana)  

NASA Astrophysics Data System (ADS)

Gold-mining is a major source of Hg pollution, especially in the tropical rain forest of South America. This pollution has been shown to strongly increase the local natural background. Does this pollution ex tend far beyond the local areas? Here we present results concerning sediments cored in the large dam lake of Petit-Saut in French Guiana. This dam lake, created in 1994, collects waters from a large catchment area where gold-mining activity has been developing since the last century. and still is. Sediment depth profiles in ^{210}Pb and in total-Hg revealed a high Hg content in the last 4 years. This can only result from anthropogenic activities, which could be due either to propagation of sediments from gold mining sites, or chemical processes acting in recently flooded soils (both processes being related to the dam creation).

Bélières, M.-A.; Pourchet, M.; Spadini, L.; Chalet, L.

2003-05-01

103

Solar total energy: large scale experiment, Shenandoah, Georgia Site. Annual report, June 1978June 1979  

Microsoft Academic Search

A background summary and a complete description of the progress and current status of activities relative to the Cooperative Agreement for the Solar Total Energy - Large Scale Experiment at the Bleyle Knitwear Plant at Shenandoah, Georgia are presented. A statement of objectives and an abstract of progress to date are included. This is followed by a short introduction containing

Ney

1979-01-01

104

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

105

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

Microsoft Academic Search

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

Kevin M. Yeager; Peter H. Santschi; H. Raifai; Monica P. Suarez; Robin Brinkmeyer; Chin-Chang Hung; Kimberly J. Schindler; Michael J. Andres; Erin A. Weaver

2007-01-01

106

Sub-decadal- to decadal-scale climate cyclicity during the Holsteinian interglacial (MIS 11) evidenced in annually laminated sediments  

NASA Astrophysics Data System (ADS)

To unravel the short-term climate variability during Marine Isotope Stage (MIS) 11, which represents a close analogue to the Holocene with regard to orbital boundary conditions, we performed microfacies and time series analyses on a ~3200-yr-long record of annually laminated Holsteinian lake sediments from Dethlingen, northern Germany. These biogenic varves comprise two sub-layers: a light sub-layer, which is controlled by spring/summer diatom blooms, and a dark sub-layer consisting mainly of amorphous organic matter and fragmented diatom frustules deposited during autumn/winter. Time series analyses were performed on the thickness of the light and dark sub-layers. Signals exceeding the 95% and 99% confidence levels occur at periods that are near-identical to those known from modern instrumental data and Holocene palaeoclimatic records. Spectral peaks at periods of 90, 25, and 10.5 yr are likely associated with the 88-, 22- and 11-yr solar cycles, respectively. This variability is mainly expressed in the light sub-layer spectra, suggesting solar influence on the palaeoproductivity of the lake. Significant signals at periods between 3 and 5 yr and at ∼6 yr are strongest expressed in the dark sub-layer spectra and may reflect an influence of the El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) during autumn/winter. Our results suggest that solar forcing and ENSO/NAO-like variability influenced central European climate during MIS 11 similarly to the present interglacial, thus demonstrating the comparability of the two interglacial periods at sub-decadal to decadal timescales.

Koutsodendris, A.; Brauer, A.; Pälike, H.; Müller, U. C.; Dulski, P.; Lotter, A. F.; Pross, J.

2011-09-01

107

Sub-decadal- to decadal-scale climate cyclicity during the Holsteinian interglacial (MIS 11) evidenced in annually laminated sediments  

NASA Astrophysics Data System (ADS)

To unravel the short-term climate variability during Marine Isotope Stage (MIS) 11, which represents a close analogue to the Holocene with regard to orbital boundary conditions, we performed microfacies and time series analyses on a ~3200-yr-long record of annually laminated Holsteinian lake sediments from Dethlingen, northern Germany. These biogenic varves comprise two sub-layers: A light layer, which is controlled by spring/summer diatom blooms, and a dark layer consisting mainly of amorphous organic matter and fragmented diatom frustules deposited during autumn/winter. Time series analyses were performed on the thickness of the light and dark layers. Signals exceeding the 95 % and 99 % confidence levels occur at periods that are near-identical to those known from modern instrumental data and Holocene palaeoclimatic records. Spectral peaks at periods of 90, 25, and 10.5 yr are likely associated with the 88-, 22- and 11-yr solar cycles, respectively. This variability is mainly expressed in the light layer spectra, suggesting solar influence on the palaeoproductivity of the lake. Significant signals at periods between 3 and 5 yr and at ~6 yr are strongest expressed in the dark layer spectra and may reflect an influence of the El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) during autumn/winter. Our results suggest that solar forcing and ENSO/NAO-like variability influenced central European climate during MIS 11 similar to the present interglacial, thus demonstrating the comparability of the two interglacial periods at sub-decadal to decadal timescales.

Koutsodendris, A.; Brauer, A.; Pälike, H.; Pross, J.; Müller, U. C.; Lotter, A. F.

2011-04-01

108

Measurement of the seasonal and annual variability of total column aerosol in a northeastern U.S. network  

SciTech Connect

A network of multi-filter rotating shadowband radiometers has operated since late 1991 in the northeastern US. The data acquired are simultaneous measurements of total and diffuse horizontal irradiances in six narrowband filtered detectors and one broadband shortwave detector. The direct normal irradiances are calculated from these measurements. These direct data are corrected for cosine response and used to calculate extraterrestrial irradiance (I{sub o}) using the Langley method of regressing the natural logarithm of direct irradiance versus air mass. With frequent determinations of I{sub o}, changes in I{sub o} caused by soiling and filter degradation, for example, can be tracked. Using these I{sub o}`s, total optical depth is calculated for every clear 30-minute period in the record. Consequently, total optical depth may be obtained on a fair number of days throughout the year. Using daily average total optical depth the authors have calculated aerosol optical depths for five wavelengths by subtracting Rayleigh scattering optical depths and Chappuis ozone absorption optical depths at each wavelength. The aerosol pattern at nearly every site is an annual cycle superimposed on a decaying stratospheric loading associated with the Mount Pinatubo volcanic eruption. An attempt is made to remove the volcanic signal using data from another site.

Michalsky, J.J.; Schlemmer, J.A.; Harrison, L.C.; Berkheiser, W.E. III [Univ. of Albany, NY (United States). Atmospheric Sciences Research Center; Larson, N.R.; Laulainen, N.S. [Pacific Northwest Lab., Richland, WA (United States)

1994-09-01

109

Alternate bearing influences annual nutrient consumption and the total nutrient content of mature pistachio trees  

Microsoft Academic Search

The influence of alternate bearing on nutrient utilization and total tree nutrient content was investigated in mature pistachio\\u000a (Pistacia vera L. cv Kerman trees). Removal of N, P and Zn in fruit and abscised leaves of cropping (‘on’) trees averaged 5, 6, and 2 times,\\u000a respectively, the removal in abscised leaflets of the non-fruiting, ‘off’ year trees. One hundred and

Patrick H. Brown; Steven A. Weinbaum; Geno A. Picchioni

1995-01-01

110

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

111

Total annual seed loss on a perennial legume through predation by insects: The importance of within-season seed and seed feeder dynamics  

Microsoft Academic Search

Determining total annual seed loss from seed predators is an important step in quantifying the role they have in modifying plant populations. Total seed loss is typically estimated with a single, well-timed survey. However, this overlooks the potential importance of within-season patterns of seed availability and insect activity, particularly where seed gain and loss are not synchronous and where insects

RIEKS D. VAN KLINKEN

2005-01-01

112

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

113

Artificial radionuclides ??Sr and ²?¹Am in the sediments of the Baltic Sea: total and spatial inventories and some temporal trends.  

PubMed

The Baltic Sea was contaminated by radioactivity following global nuclear fallout and later by the Chernobyl accident. Despite the decrease of radioactivity caused by radioactive decay, radionuclides have a prolonged residence time in the water of the Baltic Sea due to slow water exchange and relatively rapid sedimentation. Very little is known about the amounts or spatial differences of ??Sr and ²?¹Am in the Baltic Sea sediments. In this study, 20 sediment cores taken around the Baltic Sea were investigated to estimate inventories of these radionuclides. The rough results show that the Chernobyl fallout added the amount of ??Sr in the same areas where the increase of ¹³?Cs can be detected, whereas this is not the case for ²?¹Am which is more evenly distributed in the sea bottom. In addition, local differences occur in the concentrations. These results are an important amendment to the radioactivity baseline of the Baltic Sea. PMID:23582977

Hutri, Kaisa-Leena; Mattila, Jukka; Ikäheimonen, Tarja Tuulikki; Vartti, Vesa-Pekka

2013-04-11

114

Lead isotopic signatures in Antarctic marine sediment cores: a comparison between 1M HCl partial extraction and HF total digestion pre-treatments for discerning anthropogenic inputs.  

PubMed

Sensitive analytical techniques are typically required when dealing with samples from Antarctica as even low concentrations of contaminants can have detrimental environmental effects. Magnetic Sector ICP-MS is an ideal technique for environmental assessment as it offers high sensitivity, multi-element capability and the opportunity to determine isotope ratios. Here we consider the Pb isotope record of five marine sediment cores collected from three sites in the Windmill Islands area of East Antarctica: Brown Bay adjacent to the current Australian station Casey, Wilkes near the abandoned US/Australian Station and McGrady Cove lying midway between the two. Two sediment pre-treatment approaches were considered, namely partial extraction with 1M HCl and total dissolution involving HF. Lead isotope ratio measurements made following sediment partial extraction provided a more sensitive indication of Pb contamination than either Pb concentrations alone (irrespective of sample pre-treatment method) or isotope ratios made after HF digestion, offering greater opportunity for discrimination between impacted and natural/geogenic samples and sites. Over 90% of the easily extractable Pb from sediments near Casey was anthropogenic in origin, consisting of Pb from major Australian deposits. At Wilkes impact from discarded batteries with a unique isotopic signature was found to be a key source of Pb contamination to the marine environment with ~70-80% of Pb being anthropogenic in origin. The country and source of origin of these batteries remain unknown. Little evidence was found suggesting contamination at Wilkes by Pb originating from the major US source, Missouri. No definitive assessment could be made regarding Pb impact at McGrady Cove as the collected sediment core was of insufficient depth. Although Pb isotope ratio signatures may indicate anthropogenic input, spatial concentration gradients at nearby Brown Bay suggest contamination at McGrady Cove is unlikely. We recommend Pb isotopic analysis following 1M HCl partial extraction pre-treatment as a powerful and sensitive method for tracing Pb contamination in marine sediments. PMID:19878971

Townsend, A T; Snape, I; Palmer, A S; Seen, A J

2009-10-29

115

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

2011-10-04

116

Historical eutrophication in Lake Taihu: evidence from biogenic silica and total phosphorus accumulation in sediments from northern part of Lake Taihu  

Microsoft Academic Search

Sediment and water from the Meiliang Bay of Lake Taihu were analyzed to examine the historical relation between the accumulation\\u000a of biogenic silica (BSi) and total phosphorus (TP). The results indicate that BSi accumulation in the northern part of Lake\\u000a Taihu had been controlled by diatom production and phosphorus loading since the 1950s. BSi accumulation increased with the\\u000a growing agricultural

Jun Li; Cong-Qiang Liu; Zhaozhou Zhu

2008-01-01

117

Application of Infrared-Attenuated Total Reflection Technique Combined with Sedimentation Phenomena to Particle Size Measurement: Fundamental Experiments on Applicability of the Method  

NASA Astrophysics Data System (ADS)

A new method using infrared attenuated total reflection (IR-ATR) spectroscopy and sedimentation of particles in a suspension was proposed for particle size measurement. The time dependence of the IR-ATR signal intensity for mono-size dispersed particles agreed qualitatively with the theoretical expectation. Content analyses of samples containing dispersed particles of two sizes gave values close to actual ones. The possibility of size distribution analysis was shown.

Sarno, B. J.; Yoshidome, T.; Ikuta, Y.; Rabor, J. B.; Tsurumura, Y.; Montecillo, M. E.; Higo, M.

2013-09-01

118

Riverine sediment inflow to Louisiana Chenier Plain in the Northern Gulf of Mexico  

NASA Astrophysics Data System (ADS)

The Louisiana Chenier Plain is a geomorphologic extension of the Mississippi Deltaic Plain, highly influenced by sediments originating from the Mississippi River. With the Mississippi River unable to avulse closer to the Plain local riverine sediment resources are integral to maintaining the physical and ecological integrity of the estuaries and marshlands. To gain insight into the sediment resources, this study assessed two decades (1990-2009) of discharge and total suspended solids (TSS) of four rivers, Sabine River, Calcasieu River, Mermentau River, and Vermilion River that flow into the Chenier Plain. The study quantified long-term sediment delivery, analyzed seasonal and inter-annual trends of sediment transport, and investigated the effect of hydrometeorological conditions on sediment yields. Total sediment delivery from the rivers over the 20-year period was 6.86 × 106 tonnes, with the Sabine River contributing 62% of the sediment load. The Sabine River also showed a significant decreasing trend (p = 0.03) in annual sediment yield. Long-term trends of sediment loads in all the rivers were influenced by their discharge, not their TSS concentrations. Annual mean sediment load was 342,950 tonnes with higher sediment loading during the winter and spring months and lower during the summer and fall months. Annual sediment inflow has the capacity to create 2.3 × 107 m2 of land to the depth of 1 cm, but most of this sediment is unable to reach the coastline. The greatest asset that these rivers provide for the Chenier Plain is sediment and freshwater for restoration of marsh lost to salinization or inundation.

Rosen, Timothy; Xu, Y. Jun

2011-12-01

119

Runoff and sediment transport from giacierized basins at the Himalayan scale  

Microsoft Academic Search

Discharge and sediment content of meltwater from Batura glacier, upper Indus basin, Karakoram mountains, were obtained hourly, providing a detailed pattern of variations during an ablation season, against which measurements over shorter periods of less-frequent sampling at other glaciers in Himalayan basins of the Indus and Ganga rivers are compared. Total annual sediment flux from Batura glacier was 3.950 Mt,

DAVID N. COLLINS

120

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...

121

Total Viable Count and Concentration of Enteric Bacteria in Bottom Sediments from the Czarna Ha?cza River , Northeast Poland  

Microsoft Academic Search

Studies were carried out to determine counts of TVC 20°C, TVC 37°C, TC, FC, FS and Clostridium perfringens in bottom sediments of the Czarna Haricza River, from about 1 cm layer, at 10 stations located in Suwatki region (stations 1 and 2), in the villages Sobolewo (stations 3 and 4), the old river bed of the Czarna Hancza and its

S. Niewolak

1998-01-01

122

Cold-season climate change versus anthropogenic nutrient input: signals preserved in chrysophyte stomatocyst assemblages from annually laminated sediments (AD 1940 - 2004) of high-Alpine Lake Silvaplana (Switzerland)  

NASA Astrophysics Data System (ADS)

Chrysophytes (classes Chrysophyceae and Synurophyceae) are mainly euplanktonic, freshwater algae. Their siliceous resting stages (stomatocysts) are often well-preserved in lake sediments. Chrysophytes were shown to have limited tolerance to changes in lake-water pH, water temperature, salinity, conductivity, trophic status and pollution. They can therefore be used to reconstruct past environmental conditions such as winter/spring (cold season) climate or anthropogenic nutrient input. To disentangle the relative influence of climatic changes versus anthropogenic nutrient inputs on stomatocyst assemblages, stomatocysts from annually-laminated (varved) sediments of high-Alpine Lake Silvaplana (south-eastern Swiss Alps, 1792 m a.s.l.) were studied. Using an environmental scanning electron microscope, more than 130 stomatocyst types were identified in 64 samples covering the period AD 1940 - 2004. Multivariate statistical analysis revealed that major changes in stomatocyst assemblages were primarily driven by climatic factors, in particular mean October to March air temperatures. Biogenic silica and diatom-inferred total phosphorus, both indicating anthropogenic nutrient input, were shown to have a secondary, yet significant impact on stomatocyst assemblages. This nutrient input did not appear to interfere with the cold-season climate signal preserved in the stomatocyst assemblages.

Baumann, E.; Kamenik, C.; de Jong, R.; Grosjean, M.

2009-04-01

123

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

124

Analysis of lake-bottom sediment to estimate historical nonpoint-source phosphorus loads  

USGS Publications Warehouse

Bottom sediment in Hillsdale Lake, Kansas, was analyzed to estimate 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. The mean annual load of phosphorus added to the lake from point sources was estimated from previous studies. A simple mass balance then was used to compute the mean annual load of phosphorus from nonpoint sources. The total mass of phosphorus in the lake-bottom sediment was estimated to be 924,000 kg, with a mean annual load of 62,000 kg. The mean annual mass of phosphorus exiting in the lake outflow was estimated to be about 8,000 kg. The mean annual loads of phosphorus added to the lake from point and nonpoint sources were estimated to be 5,000 and 65,000 kg, respectively. Thus, the contribution to the total mean annual phosphorus load in Hillsdale Lake is about 7 percent from point sources and about 93 percent from nonpoint sources.

Juracek, K. E.

1998-01-01

125

LONG-TERM PATTERNS OF SEDIMENT TRANSPORT AFTER TIMBER HARVEST, WESTERN CASCADE MOUNTAINS, OREGON, USA  

Microsoft Academic Search

Suspended and bedload sediments were sampled from 1958-1988 on three small watersheds in the western Cascade Range in Or- egon. Annual sediment yields varied greatly among watersheds, and the pattern of long-term sediment production reflects their timber harvest and mass movement histories. Total yields from 1958-1988 were 5100 t km-2 in the clearcut watershed (WS l), 21000 t km-2 in

G. E. GRANT; A. L. WOLFF

1991-01-01

126

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

127

Annual Dissolved Nitrite Plus Nitrate and Total Phosphorous Loads for the Susquehanna, St. Lawrence, Mississippi-Atchafalaya, and Columbia River Basins, 1968-2004.  

National Technical Information Service (NTIS)

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 ...

B. T. Aulenbach

2006-01-01

128

A wood-strand material for wind erosion control: effects on total sediment loss, PM10 vertical flux, and PM10 loss.  

PubMed

Fugitive dust from eroding land poses risks to environmental quality and human health, and thus, is regulated nationally based on ambient air quality standards for particulate matter with mean aerodynamic diameter < or = 10 microm (PM10) established in the Clean Air Act. Agricultural straw has been widely used for rainfall-induced erosion control; however, its performance for wind erosion mitigation has been less studied, in part because straw is mobile at moderate wind velocities. A wood-based long-strand material has been developed for rainfall-induced erosion control and has shown operational promise for control of wind-induced erosion and dust emissions from disturbed sites. The purpose of this study was to evaluate the efficacy of both agricultural straw and wood-strand materials in controlling wind erosion and fugitive dust emissions under laboratory conditions. Wind tunnel tests were conducted to compare wood strands of several geometries to agricultural wheat straw and bare soil in terms of total sediment loss, PM10 vertical flux, and PM10 loss. Results indicate that the types of wood strands tested are stable at wind speeds of up to 18 m s(-1), while wheat straw is only stable at speeds of up to 6.5 m s(-1). Wood strands reduced total sediment loss and PM10 emissions by 90% as compared to bare soil across the range of wind speeds tested. Wheat straw did not reduce total sediment loss for the range of speeds tested, but did reduce PM10 emissions by 75% compared to a bare soil at wind speeds of up to 11 m s(-1). PMID:19141803

Copeland, N S; Sharratt, B S; Wu, J Q; Foltz, R B; Dooley, J H

2009-01-13

129

Sediment transport by streams draining into the Delaware Estuary  

USGS Publications Warehouse

The quantity of sediment transported by streams draining into the Delaware estuary from Pennsylvania, New Jersey, and Delaware varies areally according to geology, physiography, and land use. Of the estimated total sediment load of 1.6 million tons entering the Delaware estuary annually, about 48 percent is contributed by the Delaware River main stem at Trenton, NJ; 34 percent by Pennsylvania tributaries; and 18 percent by New Jersey and Delaware tributaries.

Mansue, Lawrence J.; Commings, Allen B.

1974-01-01

130

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

131

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...

132

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

133

Annual Family Income  

Center for Drug Evaluation (CDER)

... Annual Family Income. Statistics. N. Valid. Missing. Total annual family income, 904, 0. Total annual family income. Frequency. Percent. ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

134

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

135

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

136

Palaeoenvironmental Reconstructions Based on Geochemical Parameters from Annually Laminated Sediments of Sacrower See (northeastern Germany) Since the 17th Century  

Microsoft Academic Search

The history of hardwater lake Sacrower See (Brandenburg, northeastern Germany) was reconstructed back to the 17th century\\u000a based on a multi-proxy study of five short sediment cores dated by varve chronology, 210Pb and 137Cs isotopes. We were able to distinguish three main phases: The lake was mesotrophic prior to the 1830s with an oxic hypolimnion.\\u000a From the early 19th century

Britta Lüder; Gerald Kirchner; Andreas Lücke; Bernd Zolitschka

2006-01-01

137

The effect of acidification on the determination of organic carbon, total nitrogen and their stable isotopic composition in algae and marine sediment.  

PubMed

We investigated the effects of sample acidification on the stable carbon and nitrogen isotopic composition (delta13C and delta15N), as well as the organic carbon (OC) and total nitrogen (TN) composition, of an algal culture and a marine sediment. Replicate measurements of untreated and acid-treated samples were made using 1 M, 2 M and 6 M HCl, 6% H2SO3 and 1 M H3PO4. For all treatments the precision of the analysis for the acid-treated sample was equal to or less than that in the non-acidified sample. For the algae, analysis of variance (ANOVA) indicated no significant differences in the mean OC and TN concentration, or delta13C and delta15N composition, between any acid treatment and non-acidified samples. For the sediment sample a comparison could only be made between the different acid treatments because the untreated contained significant amounts ( approximately 30%) of carbonate carbon. ANOVA indicated that the mean OC determined in sediment samples after the 1 M HCl treatment and the mean delta13C values after the 6% H2SO3 and 1 M H3PO4 treatments were significantly different (p < 0.013 and < .05, respectively) from all other treatments. Mass balance calculations indicate that in some instances delta13C values were biased due to a contribution from unreacted carbonate carbon. There were no significant differences in the mean TN between any acid-treated and non-acidified samples. The mean delta15N values after 6 M HCl, 6% H2SO3 and 1 M H3PO4 treatments were significantly different from the untreated sediment sample (p < 0.044). Based on the significant bias observed for the delta15N and delta13C values, a weak (1-2 M) HCl solution is confirmed as the most appropriate acid for the removal of inorganic carbon from natural materials requiring elemental and isotopic analysis. PMID:15776498

Kennedy, Paul; Kennedy, Hilary; Papadimitriou, Stathis

2005-01-01

138

Elephant trail runoff and sediment dynamics in northern Thailand.  

PubMed

Although elephants may exert various impacts on the environment, no data are available on the effects of elephant trails on runoff, soil erosion, and sediment transport to streams during storms. We monitored water and sediment fluxes from an elephant trail in northern Thailand during seven monsoon storms representing a wide range of rainfall energies. Runoff varied from trivial amounts to 353 mm and increased rapidly in tandem with expanding contributing areas once a threshold of wetting occurred. Runoff coefficients during the two largest storms were much higher than could be generated from the trail itself, implying a 4.5- to 7.9-fold increase in the drainage areas contributing to storm runoff. Clockwise hysteresis patterns of suspended sediment observed during most storms was amplified by a "first flush" of sediment early on the hydrograph in which easily entrained sediment was transported. As runoff areas expanded during the latter part of large storms, discharge increased but sediment concentrations declined. Thus, sediment flux was better correlated to kinetic energy of rainfall on the falling limbs of most storm hydrographs compared to rising limbs. Based on a power function relationship between sediment flux and storm kinetic energy, the estimated annual sediment yield from the trail for 135 storms in 2005 was 308 to 375 Mg ha(-1) yr(-1), higher than from most disturbed land surfaces in the tropics. The eight largest storms (30% of total storm energy) in 2005 transported half of the total annual sediment. These measurements together with site investigations reveal that highly interconnected elephant trails, together with other source areas, directly link runoff and sediment to streams. PMID:20400583

Sidle, Roy C; Ziegler, Alan D

2010-04-13

139

Sedimentation and Occurrence and Trends of Selected Nutrients, Other Chemical Constituents, and Diatoms in Bottom Sediment, Fall River Lake, Southeast Kansas, 1948-2006  

USGS Publications Warehouse

A combination of available bathymetric-survey information and bottom-sediment coring was used to investigate sedimentation and the occurrence of selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 25 trace elements, diatoms, and the radionuclide cesium-137 in the bottom sediment of Fall River Lake, southeast Kansas. The total estimated volume and mass of bottom sediment deposited from 1948 through 2006 in the original conservation pool of the reservoir was 470 million cubic feet and 18.8 billion pounds, respectively. The estimated sediment volume occupied about 36 percent of the original conservation-pool, water-storage capacity of the reservoir. Mean annual net sediment deposition since 1948 in the original conservation pool of the reservoir was estimated to be 324 million pounds per year. Mean annual net sediment yield from the Fall River Lake Basin was estimated to be 585,000 pounds per square mile per year. The mean annual net loads of total nitrogen and total phosphorus deposited in the bottom sediment of Fall River Lake were estimated to be 648,000 pounds per year and 267,000 pounds per year, respectively. The estimated mean annual net yields of total nitrogen and total phosphorus from the Fall River Lake Basin were 1,170 pounds per square mile per year and 480 pounds per square mile per year, respectively. Throughout the history of Fall River Lake, total nitrogen and total phosphorus concentrations in the deposited sediment were relatively uniform. Trace element concentrations in the bottom sediment of Fall River Lake generally were uniform over time. Arsenic, chromium, nickel, and zinc concentrations typically exceeded the threshold-effects guidelines, which represent the concentrations above which toxic biological effects occasionally occur. Trace element concentrations did not exceed the probable-effects guidelines (available for eight trace elements), which represent the concentrations above which toxic biological effects usually or frequently occur. Diatom occurrence in the bottom sediment of Fall River Lake was dominated by the species Aulacoseira granulata, which is an indicator of eutrophic (nutrient-rich) conditions. The abundance of the diatom Aulacoseira granulata, combined with cyanobacteria evidence and historical water-quality data, indicated that Fall River Lake likely has been eutrophic throughout much of its history.

Juracek, Kyle E.

2008-01-01

140

The pollen season dynamics and the relationship among some season parameters (start, end, annual total, season phases) in Kraków, Poland, 1991-2008.  

PubMed

The dynamics of 15 taxa pollen seasons in Kraków, in 1991-2008 was monitored using a Burkard volumetric spore trap of the Hirst design. The highest daily pollen concentrations were achieved in the first half of May, and they were caused mainly by Betula and Pinus pollen. The second period of the high concentrations took place from the middle of July to the end of August (mainly Urtica pollen). Tree pollen seasons were shorter (18-24 days) in comparison with the most herbaceous pollen seasons (73-89 days), except at Artemisia and Ambrosia seasons (30 and 24 days, respectively). The season phases (percentyles) of the spring and late-summer taxa were the most variable in the consecutive years. The highest annual sums were noted for Urtica, Poaceae (herbaceous pollen seasons) and for Betula, Pinus, Alnus (tree pollen seasons), and the highest variability of annual totals was stated for Urtica, Populus, Fraxinus and the lowest for Ambrosia, Corylus, Poaceae. For the plants that pollinate in the middle of the pollen season (Quercus, Pinus and Rumex), the date of the season start seems not to be related to the season end, while for late pollen seasons, especially for Ambrosia and Artemisia, the statistically negative correlation between the start and the end season dates was found. Additionally, for the most studied taxa, the increase in annual pollen totals was observed. The presented results could be useful for the allergological practice and general botanical knowledge. PMID:21892249

Myszkowska, D; Jenner, B; St?palska, D; Czarnobilska, E

2010-12-29

141

Frequency distribution for suspended sediment loads  

Microsoft Academic Search

A method is described for deriving a frequency distribution for suspended sediment loads. The method uses a curvilinear regression relation between the logarithm of annual flood peaks and the logarithm of suspended sediment loads associated with that flood peak. It combines this relation with a log-Pearson type III distribution for annual floods to produce a sediment load frequency distribution. Suspended

R. S. Parker; Brent M. Troutman

1989-01-01

142

75 FR 9601 - Notice of Annual Adjustment of the Cap on Average Total Assets That Defines Community Financial...  

Federal Register 2010, 2011, 2012, 2013

...Adjustment of the Cap on Average Total Assets That Defines Community Financial Institutions...has adjusted the cap on average total assets that defines a ``Community Financial...Corporation and that has average total assets below a statutory cap. See 12...

2010-03-03

143

76 FR 3142 - Notice of Annual Adjustment of the Cap on Average Total Assets That Defines Community Financial...  

Federal Register 2010, 2011, 2012, 2013

...Adjustment of the Cap on Average Total Assets That Defines Community Financial Institutions...has adjusted the cap on average total assets that defines a ``Community Financial...Corporation and that has average total assets below a statutory cap. See 12...

2011-01-19

144

78 FR 19262 - Notice of Annual Adjustment of the Cap on Average Total Assets That Defines Community Financial...  

Federal Register 2010, 2011, 2012, 2013

...Adjustment of the Cap on Average Total Assets That Defines Community Financial Institutions...has adjusted the cap on average total assets that defines a ``Community Financial...Corporation and that has average total assets below a statutory cap.\\2\\ The...

2013-03-29

145

77 FR 14366 - Notice of Annual Adjustment of the Cap on Average Total Assets That Defines Community Financial...  

Federal Register 2010, 2011, 2012, 2013

...Adjustment of the Cap on Average Total Assets That Defines Community Financial Institutions...has adjusted the cap on average total assets that defines a ``Community Financial...Corporation and that has average total assets below a statutory cap.\\2\\ The...

2012-03-09

146

Sediment discharge in the Upper Arroyo Grande and Santa Rita Creek basins, San Luis Obispo County, California  

USGS Publications Warehouse

Sediment data collected in the upper Arroyo Grande and Santa Rita Creek basins, San Luis Obispo County, California, during the 1968-73 water years were analyzed to determine total sediment discharge at four stations in the basins. Water discharge and total sediment discharge at these stations, representative of the 1943-72 period, were estimated from long-term flow data for nearby gaging stations and water-sediment discharge relations determined for the 1968-73 water years. Most of the total annual sediment discharge at each station occurs during a few days each year. The quantity of sediment transported in a single day often accounts for more than 40 percent of the total annual sediment discharge. Estimated sediment discharge for the upper Arroyo Grande and Santa Rita Creek basins during the 1943-72 water years averaged 53,000 tons and 23,000 tons per year. Long-term sediment deposition in Lopez Reservoir, which is in the southern part of the upper Arroyo Grande basin, was estimated to be 35 acre-feet per year. (Woodard-USGS)

Knott, J. M.

1976-01-01

147

SEDIMENTATION PATTERNS AND DEPOSITION IN THE PROGRADING WAX LAKE DELTA  

NASA Astrophysics Data System (ADS)

The Mississippi River has been dammed and levied since the 1950s to control the river from flooding and support navigation and commerce. Sediments delivered to the Louisiana delta plain have decreased by half since the major projects of the 1950’s. Despite significant reductions in sediment load, the Wax Lake Delta is forming at the mouth of a man made dredged channel that flows off of the Atchafalaya River, which is the principal distributary of the Mississippi River. The remaining sediments carried by the Mississippi River are essential in the building of delta wetlands and helping to reverse coastal wetland loss. This study analyzes pre- and post-elevation data from 2008 and 2009 to understand the amount of elevation gain and sediment deposition associated with large river floods. Mean wetland elevation gain during the floods of 2008 and 2009 was 3.9 cm and 2.2 cm, respectively. Using soil bulk properties and mean elevation gain, I estimated that 2.3x106 Mt and 1.2x106Mt of sediment was deposited in the Wax Lake Delta wetlands for 2008 and 2009, respectively. If the total annual load of sediments in the Atchafalaya River is approximately 50Mt yr-1, we can estimate that <10% of the total available sediment load is deposited in the wetlands, just during spring flood events. This study provides good first order estimates of sediment deposition that can contribute to future research and understanding of the Wax Lake Delta formation and maintenance.

Bailey, C. H.; Holm, G. O.

2009-12-01

148

Status report and FY95 plans -- Re-evaluation of NOAA Dobson spectrophotometer total ozone data. 1994 annual report  

SciTech Connect

The goal of this project was to re-evaluate NOAA/CMDL Dobson spectrophotometer total ozone data during FY94 from the stations Haute Provence, France; Lauder, New Zealand; Perth, Australia; and Poker Flat, Alaska and the Umkehr data from Boulder, Colorado and Mauna Loa, Hawaii. During the second year the authors planned to re-evaluate total ozone data from Byrd, Hallett and South Pole, Antarctica; Fairbanks, Alaska; Puerto Montt, Chile; Huancayo, Peru and Umkehr data from Huancayo.

NONE

1994-12-31

149

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

150

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

151

Development and evaluation of a new catchment-scale model of floodplain sedimentation  

NASA Astrophysics Data System (ADS)

Fine-sediment storage within floodplain systems typically represents a significant component of the catchment sediment budget and a primary control on sediment-associated nutrient and contaminant fluxes at the basin scale. However, quantitative modeling of floodplain sedimentation within whole catchments represents a significant challenge, not least because hydraulic controls on sediment transport and deposition processes operate at fine spatial scales that cannot be resolved by basin-scale models. This paper outlines a new approach to addressing this problem in order to develop a computationally efficient model of floodplain sedimentation, which retains a strong physical basis. The approach involves two stages. First, a simple theoretical model of overbank sedimentation is presented, which quantifies the relationship between floodplain geometry, overbank discharge, and total sedimentation rate. Second, the precise form that such a relationship should take is established by analysis of the output from high-resolution flow and suspended sediment transport models applied to 22 floodplain reaches along three U.K. rivers. This analysis supports a simple power law model between discharge in excess of bankfull and sedimentation rate per unit valley floor length per unit sediment concentration. The power law model is then incorporated within a sediment budget framework and implemented using a Monte Carlo approach to allow an assessment of uncertainty in the model parameterization. The relative likelihood of competing model structures is determined using estimates of mean annual floodplain sediment storage derived by analysis of the 137Cs content of floodplain sediment cores. Comparison of 137Cs-derived sedimentation rates with uncertainty-bounded model predictions highlights the potential for assessing the significance of overbank sedimentation within catchment sediment budgets using the simple power law model.

Nicholas, A. P.; Walling, D. E.; Sweet, R. J.; Fang, X.

2006-10-01

152

Assessment of terrigenous organic carbon input to the total organic carbon in sediments from Scottish transitional waters (sea lochs): methodology and preliminary results  

NASA Astrophysics Data System (ADS)

This paper addresses the assessment of terrestrially derived organic carbon in sediments from two Scottish sea lochs. The results illustrate a smooth decrease in area-specific sediment oxygen uptake rates along a transect of six stations from the head of Loch Creran to the sea, from 18.7 mmol O2m-2d-1 to 6.6 mmol O2m-2d-1. Measurement of the losses on ignition at two temperatures (250°C and 500°C) of the sediment fraction from 1-2 cm depth at the same stations enabled the proportion of weight loss that occurred over the high temperature range to be calculated. These show a smooth increase from 0.33 to 0.62. These observations indicate that (a) the amount of easily biodegradable organic material in the sediment decreases by two-thirds along the transect and (b) the proportion of refractory organic material in the sediment increases along the same transect. This suggests strongly that terrigenous organic material, brought down by the River Creran is a very important fuel for sediment diagenetic processes in this system. Preliminary analyses of the lignin composition of the same sediments indicate the predominance of non-woody gymnosperm tissue. Lignin is used as a proxy for terrigenous allochthonous material. Comparative data for Loch Etive are also presented.

Loh, P. S.; Reeves, A. D.; Overnell, J.; Harvey, S. M.; Miller, A. E. J.

153

Comparative Aspects of Sulfur Mineralization in Sediments of a Eutrophic Lake Basin †  

PubMed Central

The net mineralization of organic sulfur compounds in surface sediments of Wintergreen Lake was estimated from a mass-balance budget of sulfur inputs and sediment sulfur concentrations. The net mineralization of organic sulfur inputs is <50% complete, which is consistent with the dominance of organic sulfur (>80% of total sulfur) in sediment. Although sediment sulfur is predominantly organic, sulfate reduction is the most significant process in terms of the quantities of sulfur transformed in surface sediments. Rates of sulfate reduction in these sediments average 7 mmol/m2 per day. On an annual basis, this rate is 19-fold greater than net rates of organic sulfur mineralization and 65-fold greater than sulfate ester hydrolysis.

King, Gary M.; Klug, M. J.

1982-01-01

154

Solar Total Energy Project, Shenandoah, Georgia site. Annual technical progress report, July 1, 1982-June 30, 1983  

SciTech Connect

A part of the National Solar Thermal Energy Program, initially funded by DOE, the Shenandoah Project, is the world's largest industrial application of the solar total energy concept. The objective of the Project is to evaluate a solar total energy system that provides electrical power, process steam, and air conditioning for a knit-wear factory (operated by Bleyle of America, Inc.). During normal operation, solar energy generates a large part of the electricity and displaces part of the fossil fuels normally used to run the factory and produce the clothing. Construction of the system was completed early in 1982, when operations were initiated. Solution of unexpected electrical and mechanical problems produced significant information for subsequent system designs. An overview of the Project and a brief System Description is presented following a chronological summary of progress. A discussion of varius anomalies, together with subsequent high quality solar and thermodynamic system performance results, is then discussed.

Not Available

1983-01-01

155

Interhemispheric ratio and annual cycle of carbonyl sulfide (OCS) total column from ground-based solar FTIR spectra  

Microsoft Academic Search

We have made extensive measurements of total column OCS by ground-based high- resolution solar Fourier transform infrared absorption spectroscopy from two southern hemisphere sites to complement earlier measurements in the northern hemisphere and to investigate the interhemispheric ratio, variability, and seasonal cycles of OCS in the atmosphere. The measurements were made at Lauder, New Zealand (45.0øS, 169.7øE, 370 rn asl,

David W. T. Griffith; Nicholas B. Jones; W. Andrew Matthews

1998-01-01

156

Solar Total Energy Project, Shenandoah, Georgia site. Annual technical progress report, July 1, 1983-June 30, 1984  

SciTech Connect

The Solar Total Energy Project (STEP) at Shenandoah, Georgia, is a cooperative effort between the United States Department of Energy (DOE) and the Georgia Power Company to further the search for new sources of energy. A part of the National Solar Thermal Energy Program, initially funded by DOE, the Shenandoah Project, is the world's largest industrial application of the solar total energy concept. The objective of the Project is to evaluate a solar total energy system that provides electrical power, process steam, and air conditioning for a knit-wear factory (operated by Bleyle of America, Inc.). During normal operation, solar energy generates a large part of the electricity and displaces part of the fossil fuels normally used to run the factory and produce the clothing. Construction of the system was completed early in 1982, when operations were initiated. Solution of unexpected electrical and mechanical problems produced significant information for subsequent system designs. A discussion of various anomalies, together with subsequent high quality solar and thermodynamic system performance results, is included.

Ney, E.J.

1984-10-01

157

Phytoremediation facilitates removal of nitrogen and phosphorus from eutrophicated water and release from sediment.  

PubMed

Phosphorus (P) fractions and the effect of phytoremediation on nitrogen and phosphorus removal from eutrophicated water and release from sediment were investigated in the eco-remediation experiment enclosures installed in the Hua-jia-chi pond (Hangzhou city, Zhejiang province, China). The main P fraction in the sediment was inorganic phosphorus (IP). For the mesotrophic sediments, IP mainly consisted of HCl-extractable P (Ca-P). The annual-average concentration of total nitrogen (TN), total phosphorus (TP) in water and the content of TN, TP in different vertical depth of sediment in the experiment enclosures with hydrophyte were always much lower than those in the control enclosure without hydrophyte and those outside of experiment enclosures. It is suggested that phytoremediation was an effective technology for N and P removal from eutrophicated water and release from sediment. PMID:18841488

Xiang, Wu; Xiao-E, Yang; Rengel, Zed

2008-10-08

158

SUSPENDED-SEDIMENT TRANSPORTS FLOWING INTO TOKYO BAY WITH A SS MONITORING NETWORK  

NASA Astrophysics Data System (ADS)

For comprehensive management of sediments of inner bays, it is important to understand the suspended-sediment transports from the watershed through rivers flowing into inner bays. However the sediment transport have not been understood especially under flood-flow conditions due to few continuous monitoring data for suspended sediment transports. For this purpose, we have installed turbidity sensors in the influent rivers into Tokyo Bay to continuously monitor SS trasnports. The observed results indicate that the coefficient b in sediment rating curve (L=aQb) are closely related to land use of the watershed. Total SS transports flowing into Tokyo Bay were annually 0.6 - 2.5*106 ton. The SS trasnports in Edogawa, Arakawa and Tamagawa Rivers are 66 % of total SS transports.

Tanaka, Kentaro; Nihei, Yasuo

159

Sediment and Carbon Budgets for Chesapeake Bay and its Watershed: Impacts of Land Clearance and Climate Variability  

NASA Astrophysics Data System (ADS)

Sediment and total organic carbon (TOC) flux from continents to oceans are factors for understanding carbon sinks in continental margins sediments in particular, and the global carbon cycle, in general. However, most estimates of river-borne sediment and TOC suffer from a lack of long-term instrumental records and a poor understanding of the impacts of human activities on sediment processes. We constructed sediment and TOC budgets for northern Chesapeake Bay and its watershed, an intensely monitored (>20 years), large (~18,000 km2 surface area, 166,000 km2 watershed area) mid-latitude (37-39° N) estuary, for both pre- (1000 AD to 1850 AD) and post-colonial (1850 to present) maximum land clearance intervals. The bay's main channel and tidal tributaries have been catchments for riverine sediment for 8,000 years such that their stratigraphic records provide a detailed history of sediment and carbon flux. Similarly, total suspended solid (TSS) and organic carbon data from monitoring programs and modeling of land-use change in the bay's watershed provide spatially-robust, independent estimates of sediment and carbon yield. Sediment core records indicate that land clearance increased mean annual riverine sediment (total sediment minus that from shoreline erosion) delivered to the northern bay channel and tributaries by 3 to 5-fold. Post-land clearance estimates from the sediment record compare favorably to independent values derived from monitoring riverine TSS and from modeling of land-surface erosion. Using an empirically-derived estimate of 3.7% for carbon content in present day mid-Atlantic sediments, we observed a 3-fold increase in terrestrially-derived carbon flux since the 1800s. In addition to the effects of land clearance, interannual variability in regional precipitation and freshwater discharge during the past 20 years results in annual carbon flux variation of more than 20% around the mean condition.

Cronin, T. M.; Saenger, C.; Willard, D. A.

2004-05-01

160

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

NASA Astrophysics Data System (ADS)

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.; Stewart, Lynne M.; Still, William T.

1992-04-01

161

Lower FEV1 in non-COPD, nonasthmatic subjects: association with smoking, annual decline in FEV1, total IgE levels, and TSLP genotypes  

PubMed Central

Few studies have investigated the significance of decreased FEV1 in non-COPD, nonasthmatic healthy subjects. We hypothesized that a lower FEV1 in these subjects is a potential marker of an increased susceptibility to obstructive lung disease such as asthma and COPD. This was a cross-sectional analysis of 1505 Japanese adults. We divided the population of healthy adults with no respiratory diseases whose FEV1/FVC ratio was ?70% (n = 1369) into 2 groups according to their prebronchodilator FEV1 (% predicted) measurements: <80% (n = 217) and ?80% (n = 1152). We compared clinical data – including gender, age, smoking habits, total IgE levels, and annual decline of FEV1 – between these 2 groups. In addition, as our group recently found that TSLP variants are associated with asthma and reduced lung function, we assessed whether TSLP single nucleotide polymorphisms (SNPs) were associated with baseline lung function in non-COPD, nonasthmatic healthy subjects (n = 1368). Although about half of the subjects with lower FEV1 had never smoked, smoking was the main risk factor for the decreased FEV1 in non-COPD, nonasthmatic subjects. However, the subjects with lower FEV1 had a significantly higher annual decline in FEV1 independent of smoking status. Airflow obstruction was associated with increased levels of total serum IgE (P = 0.029) and with 2 functional TSLP SNPs (corrected P = 0.027–0.058 for FEV1% predicted, corrected P = 0.015–0.033 for FEV1/FVC). This study highlights the importance of early recognition of a decreased FEV1 in healthy subjects without evident pulmonary diseases because it predicts a rapid decline in FEV1 irrespective of smoking status. Our series of studies identified TSLP variants as a potential susceptibility locus to asthma and to lower lung function in non-COPD, nonasthmatic healthy subjects, which may support the contention that genetic determinants of lung function influence susceptibility to asthma.

Masuko, Hironori; Sakamoto, Tohru; Kaneko, Yoshiko; Iijima, Hiroaki; Naito, Takashi; Noguchi, Emiko; Hirota, Tomomitsu; Tamari, Mayumi; Hizawa, Nobuyuki

2011-01-01

162

The Sediment-delivery Fallacy  

NASA Astrophysics Data System (ADS)

The expression `sediment-delivery rate' was used by Glymph (1954) to denote the percentage relationship between annual sediment yield of a catchment and the annual gross erosion of the catchment. In subsequent literature, `sediment-delivery ratio' has been used. The latter is preferable. These ratios are typically less, often much less, than one. Both Boyce (1975) and Graf (1988) recognised that such ratios are problematic. They contravene Playfair's Law and mean that catchments must progressively fill with undelivered sedim ent. Both catchment sediment yield and gross erosion are measured in units of weight/area. These units are inappropriate for the data on which the ratios are based. Sediment yield is obtained either by measuring sedimentation in reservoirs or by sampling the sediment load carried in streamflow. These data are fluxes. There is no basis for assuming that the sediment flux at a point along a stream is proportional to the catchment area. Likewise, for hillslope erosion, it cannot be assumed that the flux of sediment measured at the outlet of an erosion plot has been derived from and is, therefore, proportional to the area of the plot. For both streams and hillslopes, data on travel distances of particles indicate that much of the sediment flux may be locally derived. The relationship of sediment flux to contributing area is both complex and dependent on the erosion processes. The sediment-delivery ratio is a fallacy born out of use of incorrect units of measurement.

Parsons, Anthony; Wainwright, John; Powell, Mark; Brazier, Richard

163

Sediment Removal.  

National Technical Information Service (NTIS)

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) suit...

S. A. Peterson

1984-01-01

164

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

165

Total and size-fractionated mass of road-deposited sediment in the city of Prince George, British Columbia, Canada: implications for air and water quality in an urban environment  

Microsoft Academic Search

Purpose  The urban sedimentary system is attracting increasing interest because of its role in influencing air and water quality. A\\u000a large amount of road-deposited sediment (RDS) lies on the road network of Prince George, a city of about 80,000 people, in\\u000a British Columbia, Canada. The objectives of this study were: (1) to determine the total mass of RDS within the city,

Philip N. Owens; Katrina A. Caley; Sarah Campbell; Alexander J. Koiter; Ian G. Droppo; Kevin G. Taylor

166

Temporal dynamics of water and sediment exchanges between the Curuaí floodplain and the Amazon River, Brazil  

NASA Astrophysics Data System (ADS)

The fluvial transport and storage of sediments within channel floodplain systems can act as important sinks of sediments. In this study, we document the role of an Amazonian floodplain (Curuaí) for sediment storage. Located on the right bank of the Amazon River, 900 km upstream of the mouth, the complex system contains more than 30 interconnected lakes linked to the mainstream by permanent and temporary channels. With an open-water area varying between 600 km2 and 2500 km2, it represents ˜13% of the total flooded area of the Amazon River, between Manaus and Óbidos. For the period 2000 2003, daily liquid and solid fluxes exchanged between the floodplain system and the Amazon River were determined using an hydrological model based on a network of gauging, meteorological and sediment monitoring stations and satellite data including radar altimetry data. Sediment accumulation occurs during the five months of the flood rise, from December to April. The export of sediments to the mainstream occurs during the low water stage while depositional processes in lakes and channels are disrupted by the wind induced re-suspension of sediments. The mean average sediment storage calculated varies between 558 and 828 × 103 t yr-1 corresponding to 5.4 (±19%) × 103 t km-1 yr-1 of sediment deposited along the 130 km reach between Juruti and Santarem. This annual storage represents between 41% and 53% of the annual flux of sediments entering this floodplain through the main channels. The associated mean specific sedimentation rate is ˜517 (±23%) t km-2 yr-1 leading to a sediment accretion rate of 1.6 mm yr-1 ± 23%.

Bourgoin, Laurence Maurice; Bonnet, Marie-Paule; Martinez, Jean-Michel; Kosuth, Pascal; Cochonneau, Gerard; Moreira-Turcq, Patricia; Guyot, Jean-Loup; Vauchel, Philippe; Filizola, Naziano; Seyler, Patrick

2007-03-01

167

Total and labile metals in surface sediments of the tropical river-estuary system of Marabasco (Pacific coast of Mexico): Influence of an iron mine  

Microsoft Academic Search

Marabasco is a tropical river-estuary system comprising the Marabasco river and the Barra de Navidad Lagoon. The river is impacted by the Peña Colorada iron mine, which produces 3.5 million tons of pellets per year. Thirteen surface sediment samples were collected in May 2005 (dry season) in order to establish background levels of Al, Cd, Co, Cu, Fe, Ni, Pb,

Ana Judith Marmolejo-Rodríguez; Ricardo Prego; Alejandro Meyer-Willerer; Evgueni Shumilin; Antonio Cobelo-García

2007-01-01

168

Lead isotopic signatures in Antarctic marine sediment cores: A comparison between 1 M HCl partial extraction and HF total digestion pre-treatments for discerning anthropogenic inputs  

Microsoft Academic Search

Sensitive analytical techniques are typically required when dealing with samples from Antarctica as even low concentrations of contaminants can have detrimental environmental effects. Magnetic Sector ICP-MS is an ideal technique for environmental assessment as it offers high sensitivity, multi-element capability and the opportunity to determine isotope ratios. Here we consider the Pb isotope record of five marine sediment cores collected

A. T. Townsend; I. Snape; A. S. Palmer; A. J. Seen

2009-01-01

169

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

170

The contribution of nitrification in the water column and profundal sediments to the total oxygen deficit of the hypolimnion of a mesotrophic lake (Grasmere, English Lake District)  

Microsoft Academic Search

Estimates ofin situ nitrifying activity have been made in the hypolimnetic water column and surface 1.0 cm of profundal sediments at 2 sites in Grasmere, a mesotrophic lake in the English Lake District. Increases of nitrate concentrations were used to estimate nitrification in the water column whereas a mini-core technique, involving the use of a nitrification inhibitor (allylthiourea), was used

Grahame H. Hall; C. Jeffries

1984-01-01

171

Spatial distribution and historical records of mercury sedimentation in urban lakes under urbanization impacts.  

PubMed

China is assumed one of the largest contributors to the world's total mercury (Hg) emissions, with a rapid increase in anthropogenic Hg emissions. However, little is known about Hg fate and transport in urban areas of China. In this study, total Hg contents in surface (0-5 cm) sediments from lakes in 14 parks (3 in the central urban core (CUC) area, 5 in the developed urban (DDU) area, 2 in the developing urban (DIU) area, and 4 in the suburban (SU) area) and (210)Pb-dated sediment cores from lakes in 5 parks (3 in the CUC and 2 in the DDU) in Shanghai were assessed to compare current patterns (urbanization effect) with the historical records of Hg emissions over the past century. Total Hg content in surface sediments showed a clear urbanization pattern. Dated sediment cores revealed a 2-3 fold increase in total Hg content, while Hg fluxes exponentially increased from ~1900 to present and accelerated since 1990 when China's economy and urbanization booms started. Anthropogenic Hg fluxes in post-2000 ranged from 253 to 1452 ?g m(-2) yr(-1), 2-7 times greater than preindustrial (pre-1900) Hg fluxes. Total Hg and Pb contents in both surface sediments and sediment cores were highly correlated and Hg flux in sediment cores also significantly correlated with annual coal consumption in the period 1949-2008. The significant correlations suggest that coal combustion is a major source of Hg emission in Shanghai. PMID:23327992

Li, Hong-Bo; Yu, Shen; Li, Gui-Lin; Deng, Hong; Xu, Bo; Ding, Jing; Gao, Jin-Bo; Hong, You-Wei; Wong, Ming-Hung

2013-01-14

172

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

National Technical Information Service (NTIS)

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. Unifica...

F. M. Tiller

1992-01-01

173

Nitrogen dynamics in sediment during water level manipulation on the Upper Mississippi River  

USGS Publications Warehouse

Nitrogen (N) has been linked to increasing eutrophication in the Gulf of Mexico and as a result there is increased interest in managing and improving water quality in the Mississippi River system. Water level reductions, or 'drawdowns', are being used more frequently in large river impoundments to improve vegetation growth and sediment compaction. We selected two areas of the Upper Mississippi River system (Navigation Pool 8 and Swan Lake) to examine the effects of water level drawdown on N dynamics. Navigation Pool 8 experienced summer drawdowns in 2001 and 2002. Certain areas of Swan Lake have been drawn down annually since the early 1970s where as other areas have remained inundated. In the 2002 Pool 8 study we determined the effects of sediment drying and rewetting resulting from water level drawdown on (1) patterns of sediment nitrification and denitrification and (2) concentrations of sediment and surface water total N (TN), nitrate, and ammonium (NH4+). In 2001, we only examined sediment NH4+ and TN. In the Swan Lake study, we determined the long-term effects of water level drawdowns on concentrations of sediment NH4+ and TN in sediments that dried annually and those that remained inundated. Sediment NH4+ decreased significantly in the Pool 8 studies during periods of desiccation, although there were no consistent trends in nitrification and denitrification or a reduction in total sediment N. Ammonium in sediments that have dried annually in Swan Lake appeared lower but was not significantly different from sediments that remain wet. The reduction in sediment NH4+ in parts of Pool 8 was likely a result of increased plant growth and N assimilation, which is then redeposited back to the sediment surface upon plant senescence. Similarly, the Swan Lake study suggested that drawdowns do not result in long term reduction in sediment N. Water level drawdowns may actually reduce water retention time and river-floodplain connectivity, while promoting significant accumulation of organic N. These results indicate that water level drawdowns are probably not an effective means of removing N from the Upper Mississippi River system.

Cavanaugh, Jennifer C.; Richardson, William B.; Strauss, Eric A.; Bartsch, Lynn A.

2006-01-01

174

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

175

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

176

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

177

Sediment deposition and occurrence of selected nutrients, other chemical constituents, and diatoms in bottom sediment, Perry Lake, northeast Kansas, 1969-2001  

USGS Publications Warehouse

A combination of bathymetric surveying and bottom-sediment coring was used to investigate sediment deposition and the occurrence of selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 26 metals and trace elements, 15 organochlorine compounds, 1 radionuclide, and diatoms in bottom sediment of Perry Lake, northeast Kansas. The total estimated volume and mass of bottom sediment deposited from 1969 through 2001 in the original conservation-pool area of the lake was 2,470 million cubic feet (56,700 acre-feet) and 97,200 million pounds (44,100 million kilograms), respectively. The estimated sediment volume occupied about 23 percent of the original conservation-pool, water-storage capacity of the lake. Mean annual net sediment deposition since 1969 was estimated to be 3,040 million pounds (1,379 million kilograms). Mean annual sediment yield from the Perry Lake Basin was estimated to be 2,740,000 pounds per square mile (4,798 kilograms per hectare). The estimated mean annual net loads of total nitrogen and total phosphorus deposited in the bottom sediment of Perry Lake were 7,610,000 pounds per year (3,450,000 kilograms per year) and 3,350,000 pounds per year (1,520,000 kilograms per year), respectively. The estimated mean annual yields of total nitrogen and total phosphorus from the Perry Lake Basin were 6,850 pounds per square mile per year (12.0 kilograms per hectare per year) and 3,020 pounds per square mile per year (5.29 kilograms per hectare per year), respectively. A statistically significant positive trend for total nitrogen deposition in the bottom sediment of Perry Lake was indicated. However, the trend may be due solely to analytical variance. No statistically significant trend for total phosphorus deposition was indicated. Overall, the transport and deposition of these constituents have been relatively uniform throughout the history of Perry Lake. On the basis of nonenforceable sediment-quality guidelines established by the U.S. Environmental Protection Agency, concentrations of arsenic, chromium, copper, and nickel in the bottom sediment of Perry Lake typically exceeded the threshold-effects levels, which represent the concentrations above which toxic biological effects occasionally occur. Most nickel concentrations also exceeded the probable-effects level, which represents the concentration above which toxic biological effects usually or frequently occur. Sediment concentrations of metals and trace elements were relatively uniform over time. Statistically significant positive depositional trends for arsenic and manganese and statistically significant negative depositional trends for beryllium, chromium, titanium, and vanadium were indicated. However, the trends may be due solely to analytical variance. Organochlorine compounds either were not detected or were detected at concentrations less than the threshold-effects levels. Evidence of a negative depositional trend for DDE (degradation product of DDT) was consistent with the history of DDT use. Other organochlorine compounds detected were DDD and dieldrin. Diatom occurrence in the bottom sediment of Perry Lake was dominated by species that are indicators of eutrophic (nutrient-rich) conditions. Thus, it was concluded that eutrophic conditions have existed during much of the history of Perry Lake. However, an increase in the relative percentage abundance of the oligotrophic (nutrient-poor) species, combined with the significant positive depositional trends for two oligotrophic species (Aulacoseira islandica and Cyclotella radiosa) and the significant negative depositional trend for one eutrophic species (Stephanodiscus niagarae), indicated that conditions in Perry Lake may have become less eutrophic in recent years. Notable changes in human activity within the basin included a substantial decrease in alfalfa production and a substantial increase in soybean production from 1965 to 2000. These and other changes in human activi

Juracek, Kyle E.

2003-01-01

178

Evaluation of water and sediment of the Graminha and Águas da Serra streams in the city of Limeira (Sp-Brazil) by Synchrotron Radiation Total Reflection X-ray Fluorescence  

NASA Astrophysics Data System (ADS)

The city of Limeira is located in the state of São Paulo, Brazil and has the second largest economy and demographic growth of the state. It comprises an expressive economy with industries in several productive sectors. The source of the Graminha and Águas da Serra streams is located within the Limeira urban zone. The streams cross part of the rural zone and unite by draining into the Piracicaba River. It is possible that these basins suffer or have already suffered the impacts of environmental pollution caused by anthropogenic factors. Since the city has galvanization industries for the production of precious and semi-precious jewels as well as imitation jewelry, the concentration descriptions and interpretations of heavy metals in waters and sediments indicate anthropogenic influence and the dumping of these compounds into the Piracicaba River. The Synchrotron Radiation Total Reflection X-Ray Fluorescence (SR-TXRF) was used for determining the metals. All measurements were performed using a white beam of synchrotron radiation for excitation and a Ge hyperpure detector. Detection limits for water samples were 0.04 ?g L - 1 and in sediment samples 0.03 ?g g - 1 for Cu and Zn elements. In the water samples, concentrations higher than permissible as established by the Brazilian legislation (CONAMA) for Al, Fe, Zn, Cr, Ni, Cu and Pb, were observed. For sediment samples, values higher than quality reference values defined by the Brazilian legislation (CETESB) were verified for Cr, Zn, Cu, Ni and Pb.

Moreira, Silvana; Fazza, Elizete Vieira

2008-12-01

179

Distribution and partitioning of heavy metals in estuarine sediment cores and implications for the use of sediment quality standards  

Microsoft Academic Search

Total metal concentrations in surface sediments and historically contaminated sediments were determined in sediment cores collected from three estuaries (Thames, Medway and Blackwater) in south-east England. The partitioning behaviour of metals in these sediments was also determined using a sequential extraction scheme. These data were then compared with sediment quality values (SQVs) to determine the potential ecotoxicological risk to sediment

K. L. Spencer; C. L. MacLeod

2002-01-01

180

Temporal variability of denitrification in estuarine sediments  

NASA Astrophysics Data System (ADS)

Sediment denitrification rates and fluxes of nitrous oxide, nitrate, nitrite and ammonium were determined at two intertidal sites in the Tamar estuary (S.W. England). High sediment nitrate uptake rates were recorded throughout the year, whereas the nitrite and ammonium fluxes were positive (from sediment to water column), with the former resulting from nitrification. Nitrous oxide flux was also positive, being largely attributable to denitrification with some contribution from nitrification or nitrification-denitrification coupling. No relationship was apparent between denitrification rate and nitrate concentration in the overlying water, invalidating the notion that denitrification automatically regulates nitrate during periods of elevated ambient concentration. However, denitrification exhibited a strong covariance with the degree of sediment bioturbation ( Nereis diversicolor), which was considered to be attributable to increased transport and supply of nitrate via Nereis burrows. Denitrification accounted for 8·5% of the annual total nitrate loading to the Tamar estuary, although a maximum of 100% was observed in summer when the phytoplankton nutrient requirement would also be highest.

Law, C. S.; Rees, A. P.; Owens, N. J. P.

1991-07-01

181

Sediment deposition and occurrence of selected nutrients and other chemical constituents in bottom sediment, Tuttle Creek Lake, Northeast Kansas, 1962-99  

USGS Publications Warehouse

A combination of bathymetric surveying and bottom-sediment coring was used to investigate sediment deposition and the occurrence of selected nutrients (total ammonia plus organic nitrogen and total phosphorus), 44 metals and trace elements, 15 organochlorine compounds, and 1 radionuclide in bottom sediment of Tuttle Creek Lake, northeast Kansas. The total estimated volume and mass of bottom sediment deposited from 1962 through 1999 in the original conservation-pool area of the lake was 6,170 million cubic feet (142,000 acre-feet) and 292,400 million pounds (133,000 million kilograms), respectively. The volume of sediment occupies about 33 percent of the original conservation-pool, water-storage capacity of the lake. Mean annual net sediment deposition since 1962 was estimated to be 7,900 million pounds (3,600 million kilograms). Mean annual net sediment yield from the Tuttle Creek Lake Basin was estimated to be 821,000 pounds per square mile (1,440 kilograms per hectare). The estimated mean annual net loads of total ammonia plus organic nitrogen and total phosphorus deposited in the bottom sediment of Tuttle Creek Lake were 6,350,000 pounds per year (2,880,000 kilograms per year) and 3,330,000 pounds per year (1,510,000 kilograms per year), respectively. The estimated mean annual net yields of total ammonia plus organic nitrogen and total phosphorus from the Tuttle Creek Lake Basin were 657 pounds per square mile per year (1.15 kilograms per hectare per year) and 348 pounds per square mile per year (0.61 kilograms per hectare per year), respectively. No statistically significant trend for total phosphorus deposition in the bottom sediment of Tuttle Creek Lake was indicated (trend analysis for total ammonia plus organic nitrogen was not performed). On the basis of available sediment-quality guidelines, the concentrations of arsenic, chromium, copper, nickel, silver, and zinc in the bottom sediment of Tuttle Creek Lake frequently or typically exceeded the threshold-effects levels established by the U.S. Environmental Protection Agency. Sediment concentrations of metals and trace elements were relatively uniform over time. Organochlorine compounds either were not detected or were detected at concentrations generally less than the threshold-effects levels. Following an initial positive trend, a statistically significant negative depositional trend was indicated for DDE (degradation product of DDT), which was consistent with the history of DDT use. Other organochlorine compounds detected included aldrin, DDD, and dieldrin. Notable changes in human activity within the basin included a substantial increase in the production of grain corn and soybeans from the 1960s to the 1990s. This increase in production was accompanied by a pronounced increase in the number of irrigated acres. Also, during the same time period, there was an overall increase in hog production. These changes in human activity have not had a discernible effect on the deposition of chemical constituents in the bottom sediment of Tuttle Creek Lake.

Juracek, K. E.; Mau, D. P.

2002-01-01

182

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

183

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

USGS Publications Warehouse

Sediment deposition, water-quality trends, and mass transport of phosphorus, nitrogen, selected trace elements, and selected pesticides within the Cheney Reservoir watershed in south-central Kansas were investigated using bathymetric survey data and reservoir bottom-sediment cores. Sediment loads in the reservoir were investigated by comparing 1964 topographic data to 1998 bathymetric survey data. Approximately 7,100 acre-feet of sediment deposition occurred in Cheney Reservoir from 1965 through 1998. As of 1998, sediment had filled 27 percent of the reservoir's inactive conservation storage pool, which is less than the design estimate of 34 percent. Mean annual sediment deposition was 209 acre-feet per year, or 0.22 acre-feet per year per square mile, and the mean annual sediment load was 453 million pounds per year. During the 3-year period from 1997 through 1999, 23 sediment cores were collected from the reservoir, and subsamples were analyzed for nutrients (phosphorus and nitrogen species), selected trace elements, and selected organic pesticides. Mean concentrations of total phosphorus in reservoir bottom sediment ranged from 94 milligrams per kilogram at the upstream end of the reservoir to 710 milligrams per kilogram farther downstream near the reservoir dam. The mean concentration for all sites was 480 milligrams per kilogram. Total phosphorus concentrations were greatest when more silt- and clay-sized particles were present. The implications are that if anoxic conditions (inadequate oxygen) occur near the dam, phosphorus could be released from the sediment and affect the drinking-water supply. Analysis of selected cores also indicates that total phosphorus concentrations in the reservoir sediment increased over time and were probably the result of nonpoint-source activities in the watershed, such as increased fertilizer use and livestock production. Mean annual phosphorus loading to Cheney Reservoir was estimated to be 226,000 pounds per year on the basis of calculations from deposited sediment in the reservoir. Mean total phosphorus concentration in the surface-water inflow to Cheney Reservoir was 0.76 milligram per liter, mean annual phosphorus yield of the watershed was estimated to be 0.38 pound per year per acre, and both are based on sediment deposition in the reservoir. A comparison of the Cheney Reservoir watershed to the Webster Reservoir, Tuttle Creek Lake, and Hillsdale Lake watersheds showed that phosphorus yields were smallest in the Webster Reservoir watershed where precipitation was less than in the other watersheds. Mean concentrations of total ammonia plus organic nitrogen in bottom sediment from Cheney Reservoir ranged from 1,200 to 2,400 milligrams per kilogram as nitrogen. A regression analysis between total ammonia plus organic nitrogen as nitrogen and sediment particle size showed a strong relation between the two variables and suggests, as with phosphorus, that total ammonia plus organic nitrogen as nitrogen adsorbs to the silt- and clay-sized particles that are transported to the deeper parts of the reservoir. An analysis of trends with depth of total ammonia plus organic nitrogen as nitrogen did not indicate a strong relation between the two variables despite the increase in fertilizer use in the watershed during the past 40 years. Selected cores were analyzed for trace elements. Concentrations of arsenic, chromium, copper, and nickel at many sites exceeded levels where adverse effects on aquatic organisms sometimes occur. Larger concentrations of these elements also occurred in sediment closer to the reservoir dam where there is a larger percentage of silt and clay in the bottom sediment than farther upstream. However, the lack of industrial or commercial land use in the watershed suggests that these concentrations may be the result of natural conditions. Organochlorine insecticides were detected in the reservoir-bottom sediment in Cheney Reservoir. DDT and its degradation products DDD and DD

Mau, D. P.

2001-01-01

184

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...

185

Predicting the spatial patterns of hillslope sediment delivery to river channels in the Murrumbidgee catchment, Australia  

NASA Astrophysics Data System (ADS)

Sediment yield data derived from long-term sedimentation rates in 26 small farm dams in SE Australia were used to calibrate a spatially distributed soil erosion and sediment delivery model (WATEM/SEDEM) that takes into account contribution from gully erosion in areas of concentrated flow. For three different land use categories (poor, moderate and good vegetative cover), a sediment transport capacity coefficient was calibrated. All other parameters being equal, it was found that sediment transport capacity for cropland is 2 times higher than for degraded pasture and 20 times higher than for native forest and good pasture. Model efficiencies for the prediction of specific and total sediment yield are 0.56 and 0.89, respectively. These model efficiencies are much higher compared to those obtained when intense erosion in concentrated flow areas is not considered explicitly. Several of the catchments that were used for the calibration have very high sediment yield rates, which are attributed to the presence of gullies. The good performance of WATEM/SEDEM to all catchments suggests that the model accounts well for gully erosion. Next, the calibrated WATEM/SEDEM was applied to the Murrumbidgee River basin (30,000 km2). A mean annual sediment input into the river channels from the hillslopes of 478,000 t was predicted. The spatial pattern of hillslope-derived suspended sediment delivery in the Murrumbidgee indicates that most of the sediment originates from a few tributaries downstream of Burrinjuck Reservoir. Given the fact that high-resolution datasets (including digital elevation models) are becoming available at reasonable cost, WATEM/SEDEM provides a powerful tool to predict hillslope sediment delivery under different environments including the spatial patterns of hillslope generated sediment fluxes.

Verstraeten, Gert; Prosser, Ian P.; Fogarty, Peter

2007-02-01

186

Recent status of total mercury and methyl mercury in the coastal waters of the northern Gulf of Mexico using oysters and sediments from NOAA's mussel watch program.  

PubMed

The current status of mercury concentrations in the Gulf of Mexico (GOM) were assessed using the Mussel Watch Program (MWP) contaminant monitoring data, which is based on the analysis of oyster tissue and sediment samples. In both matrices, tHg and MeHg concentrations varied broadly. Significant concentration differences (p<0.05) between the sub-regions of the eastern, central and western Gulf were observed with maximum concentrations (hotspots) found at specific sites all across the Gulf. Compared to the Food and Drug Administration's action level in seafood, maximum mercury values were low. Based on the long-term MWP data, tHg in tissues show fairly static temporal trends along the central and western Gulf coast, while strong decreasing trends were observed in the eastern Gulf. However, the presence of mercury hotspots indicates that mercury is still a concern in the GOM. The results complement existing information to further the understanding of mercury distributions in the GOM. PMID:22938653

Apeti, D A; Lauenstein, G G; Evans, D W

2012-08-29

187

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

Microsoft Academic Search

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

Tiller

1992-01-01

188

Effect of seasonal sediment storage in the lower Mississippi River on the flux of reactive particulate phosphorus to the Gulf of Mexico  

Microsoft Academic Search

The annual surface water flux of total reactive (i.e., potentially bioavailable) particulate P from the Mississippi River was estimated by measuring the reactive (including labile, iron, organic, and calcium bound) and nonreactive (detrital) P phases in suspended particulates in the Mississippi River. In addition, the transformation of the major sediment P phases resulting from seasonal channel storage and resuspension was

Martha Sutula; Thomas S. Bianchi; Brent A. McKee

2004-01-01

189

Background concentrations of radionuclides in soils and river sediments in northern New Mexico, 1974-1986  

SciTech Connect

This report documents the range and the upper limit for background concentrations of radionuclides and radioactivity in soils and river sediments that occur as natural rock-forming minerals and worldwide fallout from atmospheric nuclear weapons tests. Documentation is based on the collection of soil and sediment in northern New Mexico and analyzed for /sup 137/Cs, /sup 238/Pu, /sup 239,240/Pu, /sup 90/Sr, total uranium, gross gamma, and tritium. The data used to establish the statistical range and upper limit of background concentration cover a 9- or 13-year period ending in 1986. The knowledge of background levels is necessary to interpret soil and sediment data collected for the annual environmental surveillance report and other reports relating to radionuclides or radioactivity in soils and sediments. 11 refs., 1 fig., 5 tabs.

Purtymun, W.D.; Peters, R.J.; Buhl, T.E.; Maes, M.N.; Brown, F.H.

1987-11-01

190

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

191

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

PubMed

Fluvial sediment is a ubiquitous pollutant that negatively affects surface water quality and municipal water supply treatment. As part of its routine water supply monitoring, the Des Moines Water Works (DMWW) has been measuring turbidity daily in the Raccoon River since 1916. For this study, we calibrated daily turbidity readings to modern total suspended solid (TSS) concentrations to develop an estimation of daily sediment concentrations in the river from 1916 to 2009. Our objectives were to evaluate long-term TSS patterns and trends, and relate these to changes in climate, land use, and agricultural practices that occurred during the 93-yr monitoring period. Results showed that while TSS concentrations and estimated sediment loads varied greatly from year to year, TSS concentrations were much greater in the early 20th century despite drier conditions and less discharge, and declined throughout the century. Against a backdrop of increasing discharge in the Raccoon River and widespread agricultural adaptations by farmers, sediment loads increased and peaked in the early 1970s, and then have slowly declined or remained steady throughout the 1980s to present. With annual sediment load concentrated during extreme events in the spring and early summer, continued sediment reductions in the Raccoon River watershed should be focused on conservation practices to reduce rainfall impacts and sediment mobilization. Overall, results from this study suggest that efforts to reduce sediment load from the watershed appear to be working. PMID:22031575

Jones, Christopher S; Schilling, Keith E

192

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

USGS Publications Warehouse

Fluvial sediment is a ubiquitous pollutant that negatively aff ects surface water quality and municipal water supply treatment. As part of its routine water supply monitoring, the Des Moines Water Works (DMWW) has been measuring turbidity daily in the Raccoon River since 1916. For this study, we calibrated daily turbidity readings to modern total suspended solid (TSS) concentrations to develop an estimation of daily sediment concentrations in the river from 1916 to 2009. Our objectives were to evaluate longterm TSS patterns and trends, and relate these to changes in climate, land use, and agricultural practices that occurred during the 93-yr monitoring period. Results showed that while TSS concentrations and estimated sediment loads varied greatly from year to year, TSS concentrations were much greater in the early 20th century despite drier conditions and less discharge, and declined throughout the century. Against a backdrop of increasing discharge in the Raccoon River and widespread agricultural adaptations by farmers, sediment loads increased and peaked in the early 1970s, and then have slowly declined or remained steady throughout the 1980s to present. With annual sediment load concentrated during extreme events in the spring and early summer, continued sediment reductions in the Raccoon River watershed should be focused on conservation practices to reduce rainfall impacts and sediment mobilization. Overall, results from this study suggest that eff orts to reduce sediment load from the watershed appear to be working. ?? 2011 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

Jones, C. S.; Schilling, K. E.

2011-01-01

193

Aquatic sediments  

SciTech Connect

A literature review of pollution in aquatic sediments is presented. Studies on analytical and sampling methods are discussed, along with heavy metals, organic compounds, and modeling and sediment transport. (JM)

DePinto, J.V.; Young, T.C.; Martin, S.C.

1983-06-01

194

Background radioactivity in sediments near Los Alamos, New Mexico.  

PubMed

River and reservoir sediments have been collected annually by Los Alamos National Laboratory since 1974 and 1979, respectively. These background samples are collected from five river stations and four reservoirs located throughout northern New Mexico and southern Colorado. Analyses include 3H, 90Sr, 137Cs, total U, 238Pu, 239,240Pu, 241Am, gross alpha, gross beta, and gross gamma radioactivity. Surprisingly, there are no federal or state regulatory standards in the USA that specify how to compute background radioactivity values on sediments. Hence, the sample median (or 0.50 quantile) is proposed for this background because it reflects central data tendency and is distribution-free. Estimates for the upper limit of background radioactivity on river and reservoir sediments are made for sampled analytes using the 0.95 quantile (two-tail). These analyses also show that seven of ten analytes from reservoir sediments are normally distributed, or are normally distributed after a logarithmic or square root transformation. However, only three of ten analytes from river sediments are similarly distributed. In addition, isotope ratios for 137Cs/238Pu, 137Cs/239,240Pu, and 239,240Pu/238Pu from reservoir sediments are independent of clay content, total organic carbon/specific surface area (TOC/SSA) and cation exchange capacity/specific surface area (CEC/SSA) ratios. These TOC/SSA and CEC/SSA ratios reflect sediment organic carbon and surface charge densities that are associated with radionuclide absorption, adsorption, and ion exchange reactions on clay mineral structures. These latter ratio values greatly exceed the availability of background radionuclides in the environment, and insure that measured background levels are a maximum. Since finer-grained reservoir sediments contain larger clay-sized fractions compared to coarser river sediments, they show higher background levels for most analytes. Furthermore, radioactivity values on reservoir sediments have remained relatively constant since the early 1980s. These results suggest that clay contents in terrestrial sediments are often more important at concentrating background radionuclides than many other environmental factors, including geology, climate and vegetation. Hence, reservoirs and floodplains represent ideal radionuclide sampling locations because fine-grained materials are more easily trapped here. Ultimately, most of these differences still reflect spatial and temporal variability originating from global atmospheric nuclear weapons testing and disintegration of nuclear-powered satellites upon atmospheric reentry. PMID:15207580

McLin, Stephen G

2004-07-26

195

Comparisons of High-Resolution Organic Paleoenvironmental Records in Five Lake Erie Sediment Cores Sampled Over a 21 Year Period  

NASA Astrophysics Data System (ADS)

We compared paleoenvironmental records of five sediment cores sampled at 1982, 1988, 1991 (two cores) and 2003 at approximately the same locations from Eastern Basin of Lake Erie to evaluate the effects on paleoenvironmental interpretations from spatial variability, that is the uneven distribution of the sediments, and the temporal variability, that is the diagenetic changes of the sediments. The high sedimentation rates of these cores (1.0cm-1.7cm/year) allow us to reconstruct annual climate changes. The paleoenvironmental proxies include total organic carbon, calcite contents, stable carbon isotopes of organic carbon and calcite, stable nitrogen isotopes, the atomic ratios of carbon and nitrogen, as well as stable oxygen isotopes of calcite. The absolute values of these proxies differ among different cores. By comparing the proxies at corresponding ages and depths, the difference seems mainly due to the uneven sediment distributions and is irrelevant of diagensis. The overall temporal patterns of paleoenvironmental proxies are consistent in multiple cores, providing strong evidence of the reliability of paleoenvironmental reconstruction on decadal scale. However, the year-to-year differences in proxies differ among different cores, questioning the reliability of reconstructing paleoenvironemental changes on annual scale. This study suggests that temporal resolution of paleoenvironmental reconstruction may be much lower compared to sediment rate and the analysis of multiple cores may be required for the studies aiming at a temporal resolution equal to sedimentation rate.

Lu, Y.; Meyers, P. A.

2008-12-01

196

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

197

Dynamics of phosphorus forms in the bottom sediments and their interstitial water for the Prut River (Moldova).  

PubMed

Phosphorus concentration in rivers results from both external inputs and internal loading from the bottom sediments. Seasonal, spatial, and multi-annual dynamics of phosphorus forms in bottom sediments and their interstitial water for the river Prut (Moldova) were evaluated. In order to determine content of total phosphorus in the bottom sediments, fresh (wet) samples were subjected to persulfate oxidation. The content of inorganic phosphorus was determined after acidic oxidation of samples. The amount of organic phosphorus was obtained by subtracting inorganic phosphorus from the amount of total phosphorus. Content of phosphorus forms in interstitial water was determined after centrifugation of fresh (wet) sediments. In general, the shape of dynamics of the amounts of inorganic phosphorus in sediments was close during years 2009, 2010, and 2011, with registered higher contents of this form on the middle course of the river. The spatial dynamics of organic phosphorus is less homogeneous along the Prut River. During 2009, higher amounts of organic phosphorus were recorded on the middle sector. During the spring of year 2010, the content of organic phosphorus in sediments was practically not changed along the river. The ratio of inorganic/organic phosphorus in bottom sediments was similar during the researched years, with the predominance of the inorganic phosphorus being recorded. Also, the increasing tendency of the percentage of organic phosphorus from spring to summer was identified. Generally, appropriate spatial and seasonal dynamics of phosphorus forms in bottom sediments and their interstitial water were recorded, although sometimes with some differences. PMID:22875423

Rusu, Vasile; Postolachi, Larisa; Povar, Igor; Alder, Alfredo; Lupascu, Tudor

2012-08-08

198

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...

199

Sediment transport by streams in the Palouse River basin, Washington and Idaho, July 1961-June 1965  

USGS Publications Warehouse

The Palouse River basin covers about 3,300 square miles in southeastern Washington and northwestern Idaho. The eastern part of the basin is composed of steptoes and foothills which are generally above an altitude of 2,600 feet; the central part is of moderate local relief and is mantled chiefly by thick loess deposits; and the western part is characterized by low relief and scabland topography and is underlain mostly by basalt. Precipitation increases eastward across the study area. It ranges annually from 12 to 18 inches in the western part and from 14 to 23 inches in the central part, and it exceeds 40 inches in the eastern part. Surface runoff from the basin for the 4-year period of study (July 1961-June 1965) averaged 408,000 acre-feet per year, compared with 445,200 acre-feet per year for the 27-year period of record. The eastern part of the basin contributed about 55 percent of the total, whereas the central and western parts contributed 37 percent and 8 percent, respectively. Most sediment transport from the Palouse River basin and the highest sediment concentrations in streams occurred in the winter. Of the several storms during the study period, those of February 3-9, 1963, December 22-27, 1964, and January 27-February 4, 1965, accounted for 81 percent of the total 4-year suspended-sediment load; the storm of February 3-9, 1963, accounted for nearly one-half the total load. The discharge-weighted mean concentration of suspended sediment carried in the Palouse River past Hooper during the study period was 2,970 milligrams per liter. The average annual sediment discharge of the Palouse River at its mouth was about 1,580,000 tons per year, and the estimated average annual sediment yield was 480 tons per square mile. The yield ranged from 5 tons per square mile from the western part of the basin to 2,100 tons per square mile from the central part. The high yield from the central part is attributed to a scarcity of vegetal cover, to the fine-grained loess soils, and to rapid runoff during winter storms. Sediment yield from the eastern part of the basin ranged from 460 to more than 1,000 tons per square mile. During high flow, silt particles make up the largest part of the suspended-sediment load, whereas during low flow, clay particles represent the greatest part. On the average, the suspended sediment transported by the Palouse River past Hooper contained 3 percent sand, 68 percent silt, and 29 percent clay. Unmeasured sediment discharge was estimated to have been 5 percent of the total sediment discharge. Data collected during the 4-year period of study show that sediment loads were higher than those recorded by V. G. Kaiser during the longer period 1939-65. Whereas Kaiser's study showed an average annual soil loss of 9.6 million tons, the average annual loss during the recent study was 14.2 million tons. The factor that has had the greatest effect on the increase of sediment yields is land use. Lands once covered and protected by natural vegetation have been extensively, cultivated, and much of the soil has become susceptible to erosion, particularly in areas mantled by loessal soils.

Boucher, P. R.

1970-01-01

200

Suspended sediment and bedload in the First Broad River Basin in Cleveland County, North Carolina, 2008-2009  

USGS Publications Warehouse

A study was conducted to characterize sediment transport upstream and downstream from a proposed dam on the First Broad River near the town of Lawndale in Cleveland County, North Carolina. Streamflow was measured continuously, and 381 suspended-sediment samples were collected between late March 2008 and September 2009 at two monitoring stations on the First Broad River to determine the suspended-sediment load at each site for the period April 2008-September 2009. In addition, 22 bedload samples were collected at the two sites to describe the relative contribution of bedload to total sediment load during selected events. Instantaneous streamflow, suspended-sediment, and bedload samples were collected at Knob Creek near Lawndale, North Carolina, to describe general suspended-sediment and bedload characteristics at this tributary to the First Broad River. Suspended- and bedload-sediment samples were collected at all three sites during a variety of flow conditions. Streamflow and suspended-sediment measurements were compared with historical data from a long-term (1959-2009) streamflow station located upstream from Lawndale. The mean streamflow at the long-term streamflow station was approximately 60 percent less during the study period than the long-term annual mean streamflow for the site. Suspended-sediment concentrations and continuous records of streamflow were used to estimate suspended-sediment loads and yields at the two monitoring stations on the First Broad River for the period April 2008-September 2009 and for a complete annual cycle (October 2008-September 2009), also known as a water year. Total suspended-sediment loads during water year 2009 were 18,700 and 36,500 tons at the two sites. High-flow events accounted for a large percentage of the total load, suggesting that the bulk of the total suspended-sediment load was transported during these events. Suspended-sediment yields during water year 2009 were 145 and 192 tons per square mile at the two monitoring stations. Historically, the estimated mean annual suspended-sediment yield at the long-term streamflow station during the period 1970-1979 was 250 tons per square mile, with an estimated mean annual suspended-sediment load of 15,000 tons. Drought conditions throughout most of the study period were a potential factor in the smaller yields at the monitoring stations compared to the yields estimated at the long-term streamflow station in the 1970s. During an extreme runoff event on January 7, 2009, bedload was 0.4 percent, 0.8 percent, and 0.1 percent of the total load at the three study sites, which indicates that during extreme runoff conditions the percentage of the total load that is bedload is not significant. The percentages of the total load that is bedload during low-flow conditions ranged from 0.1 to 90.8, which indicate that the bedload is variable both spatially and temporally.

Hazell, William F.; Huffman, Brad A.

2011-01-01

201

Sediment Loads and Yield, and Selected Water-Quality Parameters in Clear Creek, Carson City and Douglas County, Nevada, Water Years 2004-07  

USGS Publications Warehouse

Some reaches of Clear Creek above U.S. Highway 395 have experienced severe erosion as a result of fires, extreme precipitation events, and past and current human activities in the basin. Previous evaluations of erosion in the basin have concluded that most of the sediment produced and transported in the basin was associated with U.S. Highway 50, a four-lane highway that roughly parallels Clear Creek through much of the basin. During this study (water years 2004-07), construction of roads and a large residential area and golf course in the area began and are likely to affect water quality and sediment transport in the basin. Sediment data were collected between October 2003 and September 2007 (water years 2004-07) from three sites along Clear Creek. Annual suspended-sediment load was estimated to range from 1,456 tons in water year 2006 to only 100 tons in water year 2004, which corresponds to suspended-sediment yields of 93.9 tons per square mile per year in 2006 to 6.4 tons per square mile per year in 2004. In water year 2006, the suspended-sediment load on December 31, 2005, alone exceeded the combined annual load for water years 2004, 2005, and 2007. Bedload sediment was estimated to comprise 73 percent of total sediment load in the creek. Mean annual suspended-sediment yield in Clear Creek basin was much greater than yields in the Logan House, Edgewood, and Glenbrook Creek basins in the adjacent Lake Tahoe basin. Comparison of data collected during this study with data collected by university researchers in the 1970s is inconclusive as to whether fundamental changes in basin sediment characteristics have occurred during the 30-year period because different methods and sampling locations were used in the earlier studies.

Seiler, Ralph L.; Wood, James L.

2009-01-01

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

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

204

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

205

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

206

An integrated suspended sediment budgeting of the agricultural Can Revull catchment (Mallorca, Spain)  

NASA Astrophysics Data System (ADS)

The Mediterranean region of Europe has a long history of human settlement and human impacts. The very high spatial and temporal variability of fluvial processes in the region also creates problems for measurement and monitoring and for assessment of effects. Extensive rainfed herbaceous crops are one of the most representative agricultural elements of this region, which should be one of the major factor affecting erosion processes. Although land use is commonly seen as resulting in increased sediment yields, the implementation of soil and water conservation practices can have the reverse effect. Sediment budgets offer a means to assess the sources, storage, rates of transport, yields, and efficiency of delivery of sediment for a range of catchment scales. Field measurements were conducted in Can Revull, a small agricultural catchment (1.03 km2) on the island of Mallorca. This study uses 137Cs measurements, sediment source fingerprinting and continuous turbidity records of four hydrological years (2004-2005 to 2007-2008) to quantify the individual components of the budget. A large proportion of the material mobilized from cultivated fields without conservation practices (gross erosion was 775 t yr-1; 1,270 t km-2 yr-1) was, however, subsequently deposited either within the field of origin (112 t yr-1; 180 t km-2 yr-1) or at intermediate locations between the source field and the channel network (field-to-channel conveyance loss was 591 t yr-1; 1,090 t km-2 yr-1). The estimates of sediment accumulation rates on the floodplain in the lower reaches of the catchment indicate that the mean sedimentation rate was 0.47 g cm-2 yr-1. This value was extrapolated to the total area of the floodplain to estimate a total annual conveyance loss or storage of 150 t yr-1. Monitoring at the catchment outlet over the study period indicated a mean annual suspended sediment yield of 7 t km-2 yr-1. The sum of the estimates of sediment yield and floodplain storage (157 t yr-1) was taken to represent the total annual input of suspended sediment to the channel system. This value was subsequently apportioned using the information provided by the fingerprinting investigation, to estimate the mass of sediment reaching the channel network from cultivated fields and from eroding channel banks. Thus the annual contribution from channel banks was estimated to be 84 t yr-1. In the case of the contributions from cultivated fields, the estimates obtained were, as expected, significantly less than the values of net soil loss from these zones provided by the 137Cs measurements due to conveyance losses associated to field-to-channel conveyance loss. The overall sediment delivery ratios (<1%) indicate that approximately 99% of the sediment mobilized by erosion within the Can Revull catchment is subsequently deposited before reaching the monitoring station. As such, the low sediment outputs from the study catchment should be seen as reflecting the importance of conveyance losses and storage rather than a lack of sediment mobilization from the catchment surface, although part of the catchment headwaters was modified historically by means of terraces and transverse walls to prevent erosion.

Estrany, J.; Garcia, C.

2012-04-01

207

RELATIONSHIPS AMONG TOTAL LIPID, LIPID CLASSES AND POLYCHLORINATED BIPHENYL CONCENTRATIONS IN TWO INDIGENOUS POPULATIONS OF RIBBED MUSSELS (GUKENSIA DEMISSA) OVER AN ANNUAL CYCLE  

EPA Science Inventory

Two indigenous ribbed mussel (Geukensia demissa) populations were sampled approximately every four weeks during 1997 to investigate the relationships among concentrations of total lipid, lipid classes, and polychlorinated biphenyls (PCBs). One population was located in a highly c...

208

Annual NASA/Contractors Conference on Quality and Productivity (7th). Total Quality Leadership. Held in Grenelefe, Florida on October 24-25, 1990.  

National Technical Information Service (NTIS)

The report is a summary of the 7th NASA/Contractors Conference on Quality and Productivity, 'Total Quality Leadership'. The Conference overviews included: Top Leadership Panel; George M. Low Trophy; Building on Strategic Planning to Advance TQM; Employee ...

1991-01-01

209

Sediment flow behaviour from small agricultural watersheds  

Microsoft Academic Search

Runoff, soil loss, sediment concentration, and particle size distribution of sediment eroded by runoff events were measured between 1976 and 2000 from 5 small agricultural watersheds on Vertisols at ICRISAT Center, Patancheru, India. The effects of storm size and land management system on total soil loss and size distribution of sediment during runoff are discussed. At the beginning of runoff

P. Pathak; S. P. Wani; Piara Singh; R. Sudi

2004-01-01

210

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

211

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

212

Monitoring sediment production from cliffs and sediment yield in a small mediterranean catchment  

NASA Astrophysics Data System (ADS)

The paper presents a method for estimating sediment production from a cliff, when only a short monitoring period is avalable, and discusses the role of the cliff as a point source in the sediment yield from the Rokava catchment. Rokava catchment is a small (20.4 km^2) mediterranean catchment situated in SW Slovenia. The monitoring method was a combination of occasional surveys with terrestrial photogrametry, that gave the volumes of eroded and deposited sediment, and more frequent observetions of sedimentation pins, which gave a more precise time profile and an insight into the dynamics of the cliff. The method that was used was based on the fact that the cliff can be divide into two parts: the upper, eroding part, and the lower part, where sediment is temporarily deposited and then flushed during intensive rains. Using this method, the amount of annual sediment production for the monitored period (2000--2002) was estimated to around 500 tonnes. The measurements of sediment yield showed that annual suspended sediment yield in the monitored period was around 1500 tonnes, while annual bedload transport was estimated to 200 tonnes. This confirmed that the cliffs are an important sediment source in the catchment, where the agricutural areas are decreasing and natural reforestation is taking place.

Petkovsek, G.; Mikos, M.; Brilly, M.

2003-04-01

213

Atmospheric deposition and marine sedimentation fluxes of polycyclic aromatic hydrocarbons in the Eastern Mediterranean Basin.  

PubMed

Atmospheric input was studied and found to be the major source of PAHs in the eastern Mediterranean open marine ecosystem. Dry and wet atmospheric deposition, air-sea exchange, and sediment trap fluxes of polycyclic aromatic hydrocarbons (PAHs) in the eastern Mediterranean basin were estimated from November 2000 to July 2002. Seven dry and four wet deposition samples were analyzed in total and PAH concentrations were determined. Airsea exchange fluxes based on air-water concentration gradientwere drawn from five air and water samples collected concurrently from a coastal area in the eastern Mediterranean. Total annual average deposition fluxes of dry, wet, and air-sea exchange sigma35PAHs were 58.0, 165.7, and -706.4 microg m(-2) y(-1), respectively. Only 1.1 and 0.7% of the total atmospheric deposition flux of PAHs was measured in the sediment traps at 280 and 1440 m depth, respectively. PMID:16955887

Tsapakis, Manolis; Apostolaki, Maria; Eisenreich, Steven; Stephanou, Euripides G

2006-08-15

214

Light fraction organic N, ammonium, nitrate and total N in a thin Black Chernozemic soil under bromegrass after 27 annual applications of different N rates  

Microsoft Academic Search

Anadequate supply of N for a crop depends among others on the amounts of N thataremineralized from the soil organic matter plus the supply of ammonium andnitrateN already present in the soil. The objective of this study was to determine thebehaviour of light fraction organic N (LFN), NH4-N, NO3-Nand total N (TN) in soil in response to different rates of

S. S. Malhi; K. S. Gill; J. T. Harapiak; M. Nyborg; E. G. Gregorich; C. M. Monreal

2003-01-01

215

Nutrient and suspended-sediment concentrations, trends, loads, and yields from the nontidal part of the Susquehanna, Potomac, Patuxent, and Choptank rivers, 1985-96  

USGS Publications Warehouse

The Chesapeake Bay River-Input Monitoring Program was established to characterize the water quality of four major rivers in Maryland, and to quantify the load and the long-term trends in concentrations of nutrients (nitrogen and phosphorus) and suspended sediment transported from the nontidal part of each river to the Chesapeake Bay. As part of the River-Input Monitoring Program, nutrient and suspended-sediment data and streamflow data were collected from 1985 through 1996 at the Susquehanna, Potomac, Patuxent, and Choptank Rivers above the points of tidal influence. The data were used to determine the effectiveness of strategies aimed at reducing nutrients entering Chesapeake Bay from its tributaries. Of the four rivers studied, the Patuxent River had the highest median concentrations of total nitrogen (2.6 milligrams per liter), total phosphorus (0.17 milligrams per liter), and suspended sediment (45 milligrams per liter) during the 12-year period. From 1985?96, flow-adjusted concentrations of total nitrogen decreased in all but the Potomac River, flow-adjusted concentrations of total phosphorus decreased in all four rivers, and flow-adjusted concentrations of suspended sediment decreased in all but the Susquehanna River. The rivers that contributed the greatest amount of streamflow to Chesapeake Bay, the Susquehanna and Potomac, also contributed the greatest nutrient loads and suspended-sediment loads to the Bay. The Susquehanna River transported the highest average-annual loads of total phosphorus (4.7 million pounds per year) and total nitrogen (146 million pounds per year), while the Potomac River transported the highest average-annual load of suspended sediment (4.1 billion pounds per year) to the Bay. Annual loads and annual mean streamflow were normalized by basin drainage area to account for some of the hydrologic differences among the river basins. An increase in precipitation from south to north is still apparent, however, when comparing the water yields among river basins. The Susquehanna River Basin had the highest median annual water yield during the study period; the other three basins all had similar water yields. The Susquehanna River and the Patuxent River had the highest median annual yields of nitrogen during the study period. The Patuxent River also had the highest median annual yield of total phosphorus during the study period, while the Potomac River had the highest median yield of suspended sediment. Annual yields of total phosphorus and suspended sediment from the Susquehanna and the Choptank River Basins are lower than those from the Potomac and Patuxent River Basins. These relatively small yields from the Susquehanna River may be due to the location of the sampling station below Conowingo Dam. A series of three dams upstream trap a large percentage of sediment and total phosphorus carried by the Susquehanna River to Chesapeake Bay.

Darrell, Linda C.; Majedi, Brenda F.; Lizarraga, Joy S.; Blomquist, Joel D.

1999-01-01

216

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

217

Sediment Tubes  

NSDL National Science Digital Library

In this activity, students will observe how different density soils and rocks behave in wind and in water. They will make predictions and careful observations as they learn about sediment transport and sediment rates in streams and rivers. Upper junior high and high school science classes can extend the activity to include environmental discussions of agricultural runoff, turbidity measurements, and/or colloids in solutions that never settle out.

Huffman, Louise

218

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

Williams, Karen

219

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

220

Sediment Yields and Sediment Sources in the Chesapeake Bay Watershed  

NASA Astrophysics Data System (ADS)

Fine-grained sediment is having an adverse effect on the living resources and habitat of the Chesapeake Bay and its watershed. In order to reduce sediment inputs to the Bay, it is necessary to quantify erosion rates and sediment yields and identify the significant sources of fine-grained sediment. Sediment sources in the Chesapeake Bay watershed were identified using different methods at several scales. At the Chesapeake Bay scale (165,800 km2), U.S. Geological Survey suspended-sediment data collected from 1985 through 2001 for 35 stations showed that 4 of the 6 highest sediment yields were in the Conestoga River Basin, Pennsylvania, which drains to the Susquehanna River. In the Susquehanna River Basin (70,190 km2), erosion rates were determined using atmospheric 10Be at 92 river outlets and confirmed that the highest rates of erosion were in the Conestoga River Basin. In three small watersheds draining to the Chesapeake Bay -- the Pocomoke River (157 km2), Little Conestoga Creek (109 km2), and Mattawoman Creek (142 km2) -- sediment sources were identified using a sediment-fingerprinting approach. In this approach, the sources of fine-grained suspended sediment in transport can be established by comparing physical and chemical properties of the suspended sediment to potential sources. In this study, suspended sediment (< 0.062 mm) collected during storm runoff was compared to upland sediment sources (cropland, construction sites, and forest) and channel corridor sources (channel banks and bed) using radionuclides (210Pb, 137Cs), stable isotopes (13C, 15N), and total C, N, and P. Preliminary results are available for two of the three watersheds. In the Pocomoke River watershed, ditch beds which were dug to drain cropland are a significant source of sediment. In the Little Conestoga Creek watershed, river banks and cropland are significant sources Erosion rates for nine cropland sites in the Little Conestoga Creek watershed were also determined with 137Cs inventories and indicated an average rate of erosion of 16.4 tons/hectare/year, which is about 25 times the sediment yield of the Little Conestoga Creek (0.65 tons/hectare/year). This finding indicates substantial sediment storage in the watershed.

Gellis, A. C.; Landwehr, J. M.; Pavich, M. J.; Hupp, C. R.; Ritchie, J. C.; Reuter, J. M.

2005-12-01

221

Sediment yield from gullies, riparian mass wasting and bank erosion in the Upper Konto catchment, East Java, Indonesia  

NASA Astrophysics Data System (ADS)

Upland watershed rehabilitation programmes in Indonesia have faced increased scrutiny for not delivering the desired reductions in downstream sedimentation rates. Partly this reflects the fact that conservation measures have not been widely adopted or maintained by upland farmers, mainly for socio-economic reasons. Another potential explanation is that sediment contributions by gullying, (riparian) mass wasting and bank erosion have been seriously underestimated or even ignored. This paper presents estimates of sediment contributions by gullies, riparian mass wasting and bank erosion in the upland volcanic Konto catchment, East Java. Runoff and sediment yield from gullies were studied in two areas with contrasting soils and land use. Gullies in the Maron area (few gullies, Andic Cambisols, maize and rice cultivation on stable broad-based terraces) were related to improper drainage of trails, roads and yards. In the Binangsri area (more widespread gullying, Eutric Cambisols, onion cultivation on forward-sloping terraces), gullying was further enhanced by the practice of downslope furrowing to promote field drainage. Estimated annual sediment yields from the two areas were strikingly different at 22-26 and 50-87 Mg ha - 1 , respectively. Riparian mass wasting was estimated to contribute ca. 4% of total sediment yield at Maron and 8-19% in the main gully system at Binangsri, with the higher value in the latter case representing the effect of extreme rainfall in the latter half of the rainy season. Short-term wet season rates of gully wall retreat at Binangsri suggested a contribution by bank erosion of ca. 3% (8% including extreme events). As such, 11-27% of the annual sediment yield at Binangsri was estimated to have come from sources other than surface erosion. Substantial volumes of sediment (29-107 Mg km - 1 of river length) were also added to streams bordered by irrigated rice fields ( sawah) in non-gullied areas, mainly through the collapse of the lowermost terraces due to undercutting.

Rijsdijk, Anton; Bruijnzeel, L. A. (Sampurno); Prins, Th. M.

2007-06-01

222

Aerobic respiration in pelagic marine sediments  

Microsoft Academic Search

Analyses for dissolved oxygen, nitrate and total CO 2 in the interstitial water have been combined with solid phase sediment analyses of carbon and nitrogen to calculate the rates of reaction and stoichiometry of decomposing organic matter in central Equatorial Pacific pelagic sediments. The diagenesis is dominated by aerobic respiration and nitrification. Organic carbon and total nitrogen decrease exponentially with

Varis Grundmanis; James W. Murray

1982-01-01

223

PCBs in Donggang River Watershed sediments, Taiwan  

Microsoft Academic Search

Polychlorinated biphenyls (PCBs) were measured in the sediments of the Donggang River Watershed, one of the most polluted bodies of water in southern Taiwan. Field data showed that detectable concentrations of 121 PCB congeners were found and total PCBs were measured in 32 out of 33 samples, and 98 congeners were detected. The total concentrations of PCBs in the sediment

Chi Y. Hsieh; Chon L. Lee; Wen C. Kuo; Ting C. Chen; Yi K. Wang; Bo Y. Yu

2011-01-01

224

Peculiarities of Recent Sedimentation in Lake Ladoga  

Microsoft Academic Search

The bulk of sedimentary material is supplied to Lake Ladoga in the form of suspension in river water. Rivers annually deliver 1.2 Mt of sedimentary material. A significant portion of clastic material in the sedimentation basin is also related to shore and bottom abrasion. Average sedimentation rate in the lake is 0.4 mm\\/yr for the last 10 ka. The wide

S. M. Usenkov

2003-01-01

225

Gully development in Pavon Creeks: Downstream sediment supply and sub-basin restoration  

NASA Astrophysics Data System (ADS)

Sediment supply in watersheds is a function of geology, climate, and land use. Small watersheds in the Coast Ranges of California can provide large volumes of sediment to downstream waterbodies due to the active tectonic setting, the Mediterranean climate, and the history of intense land use. The Pavon Creeks sub-basin, a 1.1 km2 tributary to Pinole Creek which drains to San Francisco Bay, California, currently provides a large supply of fine-grained sediment to the detriment of creek function and native species habitat. The sub-basin is situated near the active Hayward Fault Zone, is underlain by highly erosive shales and siltstones, and has experienced over 100 years of cattle grazing. Despite only comprising 3% of the total watershed area, the Pavon Creeks sub-basin has been identified as one of the largest sources of fine sediment within the Pinole Creek watershed. To protect creek function and habitat, watershed stakeholders have prioritized preventing excess fine sediment delivery to Pinole Creek. The sub-basin includes four small ephemeral gully channels that are primarily actively eroding, downcutting, and extending over their length, and secondarily aggrading over a shorter localized reach. Field-based geomorphic data including channel cross-sections, longitudinal profiles, bank pins, and headcut monitoring have documented channel incision, erosion, and lengthening of the channel network over six years. During Water Year 2006, the first and wettest year of measurements, we observed maximum rates of incision of 0.75 m, lateral bank erosion of 2.5 m, and gully extension of 16.3 m. Annual repeat surveys show continued gully evolution, and allowed for quantitative assessment of incision, aggradation, and extension rates over this time period, as well as eroded sediment volume. We found that the largest storm events of a season cause the greatest instantaneous amount of change in the sub-basin, but cumulative seasonal rainfall determines the total amount and rate of annual erosion. The underlying complex structure of the bedrock appears to be controlling the location of the gullies, while the lithology is controlling erosion processes and rates. In 2010, local land managers completed an extensive mitigation project within the sub-basin, utilizing our geomorphic data and observations. Key components of the restoration are halting headward gully extension, controlling channel bed elevations, and re-contouring banks to reduce bank erosion and supply of sediment downstream to sensitive aquatic habitat reaches and to the flood-control channel. Much of the sub-basin drainage is now routed into sediment basins, where after just a single wet season, extensive delta deposits have formed, necessitating sediment removal to occur much sooner than anticipated.

Pearce, S.; McKee, L. J.

2011-12-01

226

Modeling sediment yields in Italian catchments  

NASA Astrophysics Data System (ADS)

Sediment yield observations, derived from 40 long-term sedimentation records in Italian reservoirs, were used to calibrate and validate the spatially distributed sediment delivery model WaTEM/SEDEM using the best data available at national scale. The sediment yield data set includes records from semi-natural catchments in northern Italy as well as agricultural and semi-natural basins in central and southern Italy. The average size of the catchments is 150 km2 with mean annual sediment yields ranging from 0.20 to 20 t ha-1 year-1. WaTEM/SEDEM estimates mean annual sediment fluxes to permanent river channels. Depending on the local transport capacity, the sediment flux is detachment-limited or transport-limited. The optimal transport capacity parameters for Italian conditions were derived via automatic calibration procedures. A global model calibration procedure taking into account all catchments in the dataset led to an overestimation of the sediment yield for the mountain catchments and an underestimation for the non-mountain catchments. Sediment yield estimates are more reliable when calibration procedures are applied separately for mountain and non-mountain catchments. The model performance of WaTEM/SEDEM is rather poor in the mountain catchments (R=0.25), which suggests that the model structure is too simplified to come to an adequate description of the sediment fluxes. The model performance for the non-mountain catchments, which are more important from a management point of view, is significantly better (R=0.51). Considering the fact that data layers with a 75×75 m resolution were used, the results are encouraging the further development and application of spatially distributed sediment yield models at regional and national scale levels.

Rompaey, Anton Van; Bazzoffi, Paolo; Jones, Robert J. A.; Montanarella, Luca

2005-02-01

227

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

228

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

229

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

230

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

231

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

232

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

233

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

234

Properties of Portland cement made from contaminated sediments  

Microsoft Academic Search

Hundreds of millions of cubic meters of contaminated sediments are dredged from US harbors and waterways annually for maintenance of navigation, environmental remediation, or both. In recent years, inexpensive ocean dumping has been largely eliminated as a disposal alternative causing a crisis in the management of sediment. This paper presents a new beneficial use alternative for contaminated dredged material, which

Jennifer L. Dalton; Kevin H. Gardner; Thomas P. Seager; Mindy L. Weimer; Jean C. M. Spear; Bryan J. Magee

2004-01-01

235

Estimating TMDL Background Suspended Sediment Loading to Great Lakes Tributaries from Existing Data  

Microsoft Academic Search

The total maximum daily load (TMDL) for suspended sediment is the maximum quantity of suspended sediment that can enter a waterway without affecting the beneficial uses of the waterway. It is calculated as the sum of permissible allotments of point sources of suspended sediment, permissible allotments of nonpoint sources of suspended sediment, background (natural) loading of suspended sediment, and a

Peter J. Whiting

2006-01-01

236

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

NASA Astrophysics Data System (ADS)

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, S. M.; Bergamaschi, B. A.; Hernes, P. J.; Kavvas, M. L.

2011-09-01

237

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, S. M.; Bergamaschi, B. A.; Hernes, P. J.; Kavvas, M. L.

2011-01-01

238

Dissolved and particulate carbohydrates in contrasting marine sediments  

Microsoft Academic Search

Dissolved and particulate carbohydrates were examined in contrasting Chesapeake Bay (estuarine) and mid-Atlantic shelf\\/slope break (continental margin) sediments. Particulate carbohydrates (PCHOs) represented ?5–9% of the total sediment particulate organic carbon (POC), and PCHO remineralization appeared to be a similar fraction of total sediment carbon oxidation (or Cox). When these results are compared with results from other coastal sediments and a

D. J. BURDIGE; A Skoog; K. GARDNER

2000-01-01

239

Earth's portfolio of extreme sediment transport events  

NASA Astrophysics Data System (ADS)

Quantitative estimates of sediment flux and the global cycling of sediments from hillslopes to rivers, estuaries, deltas, continental shelves, and deep-sea basins have a long research tradition. In this context, extremely large and commensurately rare sediment transport events have so far eluded a systematic analysis. To start filling this knowledge gap I review some of the highest reported sediment yields in mountain rivers impacted by volcanic eruptions, earthquake- and storm-triggered landslide episodes, and catastrophic dam breaks. Extreme specific yields, defined here as those exceeding the 95th percentile of compiled data, are ~ 104 t km- 2 yr- 1 if averaged over 1 yr. These extreme yields vary by eight orders of magnitude, but systematically decay with reference intervals from minutes to millennia such that yields vary by three orders of magnitude for a given reference interval. Sediment delivery from natural dam breaks and pyroclastic eruptions dominate these yields for a given reference interval. Even if averaged over 102-103 yr, the contribution of individual disturbances may remain elevated above corresponding catchment denudation rates. I further estimate rates of sediment (re-)mobilisation by individual giant terrestrial and submarine mass movements. Less than 50 postglacial submarine mass movements have involved an equivalent of ~ 10% of the contemporary annual global flux of fluvial sediment to Earth's oceans, while mobilisation rates by individual events rival the decadal-scale sediment discharge from tectonically active orogens such as Taiwan or New Zealand. Sediment flushing associated with catastrophic natural dam breaks is non-stationary and shows a distinct kink at the last glacial-interglacial transition, owing to the drainage of very large late Pleistocene ice-marginal lakes. Besides emphasising the contribution of high-magnitude and low-frequency events to the global sediment cascade, these findings stress the importance of sediment storage for fuelling rather than buffering high sediment transport rates.

Korup, Oliver

2012-05-01

240

River sediments.  

PubMed

River history is reflected in the nature of the sediments carried and deposited over time. Using examples drawn from around the world, this account illustrates how river sediments have been used to reconstruct past environmental changes at a variety of scales in time and space. Problems arising from a patchy alluvial record and from influences external to the river basin can make interpretation difficult. The Nile is treated in some detail because its history is further complicated by tectonic, volcanic and climatic events in its headwaters and by enduring human impacts. It arose soon after 30 Ma. Since that time approximately 100,000 km(3) of rock have been eroded from its Ethiopian sources and deposited in the eastern Mediterranean, with minor amounts of sediment laid down along its former flood plains in Egypt and Sudan. From these fragmentary alluvial remains, a detailed history of Nile floods and droughts has been reconstructed for the last 15 kyr, and, with less detail, for the past 150 kyr, which shows strong accordance with global fluctuations in the strength of the summer monsoon, which are in turn perhaps modulated by changes in solar insolation caused by changes in the Earth's orbit and by variations in solar irradiance. PMID:22474677

Williams, Martin

2012-05-13

241

Visual sedimentation.  

PubMed

We introduce Visual Sedimentation, a novel design metaphor for visualizing data streams directly inspired by the physical process of sedimentation. Visualizing data streams (e. g., Tweets, RSS, Emails) is challenging as incoming data arrive at unpredictable rates and have to remain readable. For data streams, clearly expressing chronological order while avoiding clutter, and keeping aging data visible, are important. The metaphor is drawn from the real-world sedimentation processes: objects fall due to gravity, and aggregate into strata over time. Inspired by this metaphor, data is visually depicted as falling objects using a force model to land on a surface, aggregating into strata over time. In this paper, we discuss how this metaphor addresses the specific challenge of smoothing the transition between incoming and aging data. We describe the metaphor's design space, a toolkit developed to facilitate its implementation, and example applications to a range of case studies. We then explore the generative capabilities of the design space through our toolkit. We finally illustrate creative extensions of the metaphor when applied to real streams of data. PMID:24051811

Huron, Samuel; Vuillemot, Romain; Fekete, Jean-Daniel

2013-12-01

242

Planktonic diatoms from sediment traps in Omura Bay, western Japan with implications for ecological and taphonomic studies of coastal marine environments  

Microsoft Academic Search

Time-series samples were collected by sediment trap at Nagayo-ura in Omura Bay, western Japan, from June 1998 to June 1999. Annual fluxes of diatom frustules in these trap samples, and in surface sediments collected beneath the sediment trap, were analyzed and compared with each other to investigate the ecology and taphonomy of marine planktonic diatoms. Calculated annual fluxes of marine

Megumi Kato; Yoshihiro Tanimura; Kazumi Matsuoka; Hitoshi Fukusawa

2003-01-01

243

Comparative Analysis of Bank Erosion and Bed Sediment Remobilization With Watershed Sediment Yield  

NASA Astrophysics Data System (ADS)

Urbanization has altered the hydrologic regime of Valley Creek, a tributary of the Schuylkill River west of Philadelphia, PA. Initial reconnaissance suggested that urban development in the watershed was associated with increased sediment flux through the 3.7 kilometer portion of Valley Creek that runs through Valley Forge National Historical Park before its confluence with the Schuylkill River. A study was conducted between September 2003 and January 2006 to obtain baseline inventories and monitor sediment transport and storage. Field methods included cross-section and bankline surveys after significant storm events (one of which was the second highest discharge on record for Valley Creek; 77.3 m3/s), pebble counts and volumetric barrel samples to measure the particle size distribution of the streambed, the use of a slide hammer to measure depth of the mobile layer, and tracer gravels to determine the sediment particle sizes mobilized as a function of discharge. A suspended sediment station installed at the USGS gage just upstream of the park boundary includes a YSI turbidity optical sensor calibrated to suspended-sediment concentrations collected by an ISCO sampler. Sediment load estimates were compiled based on turbidity data collected at 15-minute intervals between July 2005 and January 2006 and preliminary USGS unit values flow records for the period 1 February 2005-31 January 2006. Suspended sediment yield for the watershed was estimated at 40 tons/km2/yr. This estimate is much lower than originally believed based on sediment yields from nearby watersheds in the region, which range from 66 to 344 tons/km2/yr. Sediment loads from measured bank erosion sites within the park were used to estimate the amount of sediment derived from bank erosion along the channel network upstream of the park boundary. Calculated values range from two-thirds to twice the annual suspended sediment load. Although bank erosion appears to be a potentially dominant source of sediment by comparison with annual suspended sediment load, comparison with the mass of fine sediment stored in the bed and fine sediment scoured from the bed during the study period suggests that bed sediment storage and remobilization is of the same order of magnitude as the mass of sediment derived from bank erosion.

Fraley, L. M.; Miller, A. J.; Welty, C.

2006-05-01

244

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

Microsoft Academic Search

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

David J. Topping; David M. Rubin; L. E. Vierra

2000-01-01

245

Water and Sediment Yield from a Deciduous Forest Ecosystem in Istanbul-Turkey  

Microsoft Academic Search

The objectives of this paper are to present annual water yield and sediment loss from a forest ecosystem consisting of completely natural broadleaved old growth oak-beech stands and to show precipitation, streamflow, and sediment discharge trends over time. An experimental watershed has been monitored since 1979 for streamflow and water quality parameters including suspended sediment discharge. Data presented in this

Süleyman ÖZHAN; Ferhat GÖKBULAK; Yusuf SERENGIL

246

Erosion, storage, and transport of sediment in two subbasins of the Rio Puerco, New Mexico  

USGS Publications Warehouse

Arroyos in the American Southwest proceed through cut-and-fill cycles that operate at centennial to millennial time scales. The geomorphic community has put much effort into understanding the causes of arroyo cutting in the late Quaternary and in the modern record (late 1800s), while little effort has gone into understanding how arroyos fill and the sources of this fill. Here, we successfully develop a geographic information system (GIS)-modeled sediment budget that is based on detailed field measurements of hillslope and channel erosion and deposition. Field measurements were made in two arroyo basins draining different lithologies and undergoing different land disturbance (Volcano Hill Wash, 9.30 km2; Arroyo Chavez, 2.11 km2) over a 3 yr period. Both basins have incised channels that formed in response to the late nineteenth-century incision of the Rio Puerco. Large volumes of sediment were generated during arroyo incision, equal to more than 100 yr of the current annual total sediment load (bed load + suspended load) in each basin. Downstream reaches in both arroyos are presently aggrading, and the main source of the sediment is from channel erosion in upstream reaches and first- and second-order tributaries. The sediment budget shows that channel erosion is the largest source of sediment in the current stage of the arroyo cycle: 98% and 80% of the sediment exported out of Volcano Hill Wash and Arroyo Chavez, respectively. The geomorphic surface most affected by arroyo incision and one of the most important sediment sources is the valley alluvium, where channel erosion, gullying, soil piping, and grazing all occur. Erosion rates calculated for the entire Volcano Hill Wash (-0.26 mm/yr) and Arroyo Chavez (-0.53 mm/yr) basins are higher than the modeled upland erosion rates in each basin, reflecting the large contributions from channel erosion. Erosion rates in each basin are affected by a combination of land disturbance (grazing) and lithology--erodible sandstones and shales in Arroyo Chavez compared with basalt for Volcano Hill Wash. Despite these differences, hillslope sediment yields are similar to long-term denudation rates. As the arroyo fills over time from mouth to headwaters, hillslope sediment becomes a more significant sediment source.

Gellis, A. C.; Pavich, M. J.; Ellwein, A. L.; Aby, S.; Clark, I.; Wieczorek, M. E.; Viger, R.

2012-01-01

247

Changes in sediment loads and discharge from small mountain catchments following wildfire in south eastern Australia  

NASA Astrophysics Data System (ADS)

A severe wildfire burnt over 1 million ha of forested land in southeastern Australia in early 2003. Included in the burnt area were two 136 and 244 ha hydrologic research catchments in the East Kiewa valley that had been decommissioned following a 10 year study, and an adjacent larger (10,050 ha) gauged catchment, the West Kiewa River. The three catchments were re-instrumented to measure discharge and suspended sediment fluxes at 15 min timesteps, with additional measurement of bedload at the East Kiewa sites. Analysis of annual rainfall discharge relationships and of flow duration curves for the first 2 post-fire water years indicated annual flow increases of around 65 75% for Slippery Rock Creek in both post-fire water years and 40% and 76 94% for Springs Creek in 2003 2004 and 2004 2005, respectively. The flow impacts on the less severely burnt West Kiewa River were far more subdued, and did not exceed pre-fire variability in annual flows. Flow duration curve analysis did not indicate changed runoff generating processes at the daily timescale, with the curves shifting upward uniformly over the flow regime. Total sediment exports increased by factors of 8 9 (up to 2.96 t ha-1 yr-1) from the East Kiewa catchments in year 1 after the fire, diminishing to a 2 4-fold increase in year 2. Flow increases accounted for much of the year 2 exports as suspended sediment concentrations decreased toward pre-fire levels. Post-fire suspended load exports from the larger West Kiewa catchment were much lower per unit area, probably reflecting the smaller area of high intensity burn, less intensive burning of riparian areas and possible scale effects. The results were observed under near-average rainfall conditions, with the exception of one short duration high intensity storm that produced almost 50% of the combined sediment loads from the East Kiewa catchments.

Lane, Patrick N. J.; Sheridan, Gary J.; Noske, Philip J.

2006-12-01

248

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

PubMed

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. PMID:21488505

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

249

Snake and Columbia Rivers Sediment Sampling Project  

SciTech Connect

The disposal of dredged material in water is defined as a discharge under Section 404 of the Clean Water Act and must be evaluated in accordance with US Environmental Protection Agency regulation 40 CFR 230. Because contaminant loads in the dredged sediment or resuspended sediment may affect water quality or contaminant loading, the US Army Corps of Engineers (USACE), Walla Walla District, has requested Battelle/Marine Sciences Laboratory to collect and chemically analyze sediment samples from areas that may be dredged near the Port Authority piers on the Snake and Columbia rivers. Sediment samples were also collected at River Mile (RM) stations along the Snake River that may undergo resuspension of sediment as a result of the drawdown. Chemical analysis included grain size, total organic carbon, total volatile solids, ammonia, phosphorus, sulfides, oil and grease, total petroleum hydrocarbons, metals, polynuclear aromatic hydrocarbons, pesticides, polychlorinated biphenyls, and 21 congeners of polychlorinated dibenzodioxins and dibenzofurans.

Pinza, M.R.; Word, J.Q; Barrows, E.S.; Mayhew, H.L.; Clark, D.R. (Battelle/Marine Sciences Lab., Sequim, WA (United States))

1992-12-01

250

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, Jr. , L. E.

2000-01-01

251

Sediment Dynamics in the Upper McKenzie River Basin, Central Oregon Cascade Range  

NASA Astrophysics Data System (ADS)

Reference and current sediment budgets were developed to evaluate the extent to which hydroelectric dams alter sediment dynamics in the upper McKenzie River basin of central Oregon. The 647 km2 study area straddles the western boundary of the High Cascades graben separating the High Cascades and Western Cascades geologic terrains. Permeable Quaternary volcanics forming the low-gradient High Cascades plateau promote surface hydrologic disconnection, nearly constant discharge controlled by groundwater emergence, and low sediment yield. In contrast, deeply weathered Tertiary volcanics, rugged topography, and a dense network of steep channels in the Western Cascades terrain promote peaked storm responses and high sediment yield by deep-seated mass movement, debris slides, and debris flows. Three independent estimates of sediment yield (application of published surface process rates, extrapolation of regional suspended load and bedload flux rates, and extrapolation of reservoir sedimentation rates) illustrate the dominant role of geologic terrains in determining the longitudinal pattern of sediment supply to the McKenzie River. Average reference yields from High Cascades and Western Cascades sources were 9 t km-2y-1 and 200 t km-2y-1, respectively. Downstream of Trail Bridge Dam, High Cascades sources (241 km2) account for 12% of the total reference yield, while Western Cascades sources (67 km2) account for 62%. Estimates of current sediment yield illustrate the offsetting effects of reservoir sediment trapping and accelerated yield related to forest management. Average current yields from High Cascades and Western Cascades sources were 17 t km-2y-1 and 300 t km-2y-1, respectively. Current yield to the McKenzie River arm of Trail Bridge Reservoir (42 km2 sourced in High Cascades terrain) was 17 t km-2y-1, while current yield to Smith Reservoir (48 km2 sourced in Western Cascades terrain) was 251 t km-2y-1. The relation between hydroelectric project effects and forest management are most apparent in the McKenzie River at Deer Creek, where current yield from Deer Creek (29% higher than reference yield) may largely compensate for sediment trapping in Smith and Trail Bridge reservoirs. The extent to which accelerated yield from Deer Creek moderates the geomorphic effects of trapping in upstream reservoirs is, in part, a function of storage changes in the alluvial reach of lower Deer Creek. Mass balance between average annual bedload transport capacity (22,000 t y-1 and 13,000 t y-1 at the upper and lower ends of the reach, respectively) and estimated coarse sediment supply (4,500 t y-1) suggests that sediment input from Deer Creek to the McKenzie River is relatively insensitive to storage changes. Since hydroelectric dams and forest management likely decrease the coarse:total sediment ratio, the geomorphic effects of reservoir sediment trapping and accelerated tributary sediment yields depend on the current grain size distribution of the sediment supply relative to that stored in upstream reservoirs.

Stallman, J. D.; Bowers, R. J.; Cabrera, N. C.; Real de Asua, R.; Wooster, J. K.

2005-12-01

252

Annual report of 1991 groundwater monitoring data for the Kerr Hollow Quarry and Chestnut Ridge Sediment Disposal Basin at the Y-12 Plant: Reporting and statistical evaluation of the subsequent year (sixth) data  

Microsoft Academic Search

This annual report has historically been prepared to meet the annual reporting requirements of the Tennessee Department of and Environment and Conservation (TDEC), Hazardous Waste Management Regulation 1200-1-11-.05 (6)(e), for detection monitoring data collected on Resource Conservation and Recovery Act (RCRA) wells in place around facilities which are accorded interim status. The regulatory authority for these units at the Y-12

L. W. McMahon; T. M. Mercier

1992-01-01

253

Entrainment and export of Laptev Sea ice sediments, Siberian Arctic  

NASA Astrophysics Data System (ADS)

Sea ice sediments (SIS; sediments rafted by ice) and shelf surface deposits from the Siberian Laptev Sea were analyzed to study turbulent entrainment processes. This study focused on the silt and clay fractions, on average representing 63.4% and 30.4% (total: 93.7%) of the bulk SIS, respectively. Generally, the SIS contains 50% more silt than the shelf deposits, while the clay percentages in both sample groups are similar. Sand-sized particles are less abundant in SIS than in bottom sediment. Although SIS is clearly enriched in silt, no evidence was found for preferential ice entrainment of any silt subfraction (coarse, medium, fine). Statistical tests of SIS and shelf silt parameters, and the similar clay mineral compositions of both sample groups, provide evidence for entrainment of Laptev bottom deposits into newly forming ice. The entrainment is related to the mechanism known as suspension freezing. Accordingly, coarser clasts (sand) and plant debris may be lifted upward by buoyant anchor ice, while coarse silt particles are supposed to be transported to the surface by rising frazil aggregates. Additionally, turbulent interaction of convergent Langmuir circulation and near-surface frazil ice streaks is proposed to support ice entrainment of the finest particles >6.4 phi (<12 ?m). Entrainment and export of SIS from the Laptev Sea were assessed for ten individual flaw leads (extended narrow polynyas separating fast and drifting ice) using particle concentrations in ice samples and new ice formation rates. The results show that roughly 20 Mt of SIS can be annually exported from the Laptev Sea by lead ice only. Thus formation and export of sediment-laden lead ice may play a major geological role in Siberian Arctic shelf erosion and coastal retreat.

Dethleff, Dirk

2005-07-01

254

Sediment Risk Assessment Workshop.  

National Technical Information Service (NTIS)

Sediments are both a source and a sink for persistent contaminants which enter the aquatic environment. Sediment quality assessments involving sediment bioassays began at about the same time as environmental risk assessment (ERA) procedures (the early 198...

G. Schiefer

1995-01-01

255

CONTAMINATED SEDIMENTS SCIENCE PRIORITIES  

EPA Science Inventory

The Contaminated Sediment Science Priorities (CSSP) document isa mechanism for the U.S. EPA to develop and coordinate Agency-wide science activities that affect contaminated sediments. It analyzes current Agency contaminated sediments science activities, identifies and evaluates...

256

Processing of a fine sediment pulse after dam removal: sediment mass balance and longitudinal trends  

NASA Astrophysics Data System (ADS)

A sediment mass balance around the site of a dam removal can provide useful insight into the processes driving and nature (e.g. magnitude, spatial extent, and duration) of downstream impacts associated with the release of fine sediment. Chiloquin Dam was removed from the Sprague River in southern Oregon in August of 2008. A sediment mass balance was calculated based on continuous suspended sediment concentrations (SSCs), which were developed over 3 years (1 year pre removal and 2 years post removal) from continuous turbidity measurements. The processing of the sediment stored behind the dam (composed primarily of sand and fines) and the resulting bedform changes were examined using annual cross section surveys, bathymetric surveys using RTK GPS and ADCP, and surface sediment characterization. Longitudinal profiles and differenced DEMs indicate that a) the sediment wedge behind the dam was not fully processed during the first 2 years post-removal due to low water but substantial processing occurred during year 3 with higher flows, b) deposition in pools downstream of the dam occurred during all years, though the magnitude and spatial extent varied with water year type, and c) transient deposition of fine sediment in downstream riffles occurred, although deposition was partially obscured by basin wide trends of fining in the absence of high flows. Results demonstrate the implications of delayed sediment processing due to low flow over the two years, limiting the extent but extending the duration of potential downstream impacts to habitat. Results are organized to outline a conceptual model for how annual hydrologic regimes (low vs. high flow years) drive temporal and spatial dynamics of sediment processing in the context of dam removal as a disturbance.

Cox, M. M.; Tullos, D. D.

2011-12-01

257

Anaerobic Oxalate Degradation: Widespread Natural Occurrence in Aquatic Sediments  

PubMed Central

Significant concentrations of oxalate (dissolved plus particulate) were present in sediments taken from a diversity of aquatic environments, ranging from 0.1 to 0.7 mmol/liter of sediment. These included pelagic and littoral sediments from two freshwater lakes (Searsville Lake, Calif., and Lake Tahoe, Calif.), a hypersaline, meromictic, alkaline lake (Big Soda Lake, Nev.), and a South San Francisco Bay mud flat and salt marsh. The oxalate concentration of several plant species which are potential detrital inputs to these aquatic sediments ranged from 0.1 to 5.0% (wt/wt). In experiments with litter bags, the oxalate content of Myriophyllum sp. samples buried in freshwater littoral sediments decreased to 7% of the original value in 175 days. This suggests that plant detritus is a potential source of the oxalate within these sediments. [14C]oxalic acid was anaerobically degraded to 14CO2 in all sediment types tested, with higher rates evident in littoral sediments than in the pelagic sediments of the lakes studied. The turnover time of the added [14C]oxalate was less than 1 day in Searsville Lake littoral sediments. The total sediment oxalate concentration did not vary significantly between littoral and pelagic sediments and therefore did not appear to be controlling the rate of oxalate degradation. However, depth profiles of [14C]oxalate mineralization and dissolved oxalate concentration were closely correlated in freshwater littoral sediments; both were greatest in the surface sediments (0 to 5 cm) and decreased with depth. The dissolved oxalate concentration (9.1 ?mol/liter of sediment) was only 3% of the total extractable oxalate (277 ?mol/liter of sediment) at the sediment surface. These results suggest that anaerobic oxalate degradation is a widespread phenomenon in aquatic sediments and may be limited by the dissolved oxalate concentration within these sediments.

Smith, Richard L.; Oremland, Ronald S.

1983-01-01

258

Plutonium mobility and its fate in soil and sediment environments  

Microsoft Academic Search

Mobile plutonium was found in waterlogged soil and reservoir sediment from the Nishiyama district of Nagasaki, accumulating from the local fallout released in the explosion of the A-bomb in 1945. Less than 10% of the total deposited plutonium had turned into a mobile form in the bottom sediment of the reservoir. The environmental conditions in the soft and sediment are

Yasunori Mahara; Akira Kudo

2001-01-01

259

Sedimentation rate determination by radionuclides mass balances  

NASA Astrophysics Data System (ADS)

In the past, uranium mining activity took place in the area around Limoges, France. Even nowadays, this activity results in an increase in the input and availability of radionuclides in aquifer reservoirs, making of this area a suitable site to better understand the behaviour of radionuclides in the surficial environment. Water was sampled monthly over the entire year 2001 in a brook that collects mine water and in a lake fed by this brook. Samples were filtered through 0.45?m filters to remove particles. Activities of 238U, 226Ra, 210Pb, 228Th and 228Ra were measured on particulate (>0.45?m), dissolved (<0.45?m) and total (unfiltered) fractions by gamma spectrometry in the well of a high efficiency, low background, germanium detector settled in an underground laboratory, protected from cosmic rays by 1700 m of rocks (LSM, CNRS-CEA, French Alps). Activities measured in particulate and dissolved fractions were summed and compared to the one measured in unfiltered water to test the filtration yield. No significant loss or contamination were detected. In the brook water, 70% of 238U, 60% of 226Ra and 80% of 210Pb are associated with particles. Activities associated with particles decrease drastically along with the velocity of current when the stream enters the lake. An annual mass balance of radionuclides carried by particles from the stream to the lake was used to determine the sedimentation rate in the lake. The flux of particles deduced from mass balance calculations based on five isotopes corresponds to the thickness of sediment accumulated since the creation of this artificial lake (that is, 1976). This study emphasises the usefulness of radionuclides as tracers for environmental investigations.

Cazala, C.; Reyss, J. L.; Decossas, J. L.; Royer, A.

2003-04-01

260

Reconnaissance study of stream sedimentation, southern Guam  

USGS Publications Warehouse

This study uses limited available data to estimate sediment yields for three basins in southern Guam. The flow-duration sediment-rating curve method, reservoir survey data, and Pacific southwest Inter-Agency Committee (PSIAC) formula were used. Daily suspended-sediment samples were collected at USGS gaging stations on the Ylig and Ugum Rivers for one year. Intermittent samples were collected from the Talofofo River for six months. Although limited, these data are used in the flow-duration sediment-rating-curve method to estimate mean suspended-sediment yields. Fena Reservoir sedimentation data are used to test the applicability of the PSIAC formula in the three basins. Estimates of suspended-sediment yields are 467 to 845, 678 to 977, and 634 to 855 tons per year per square mile for the Talofofo, Ylig, and Ugum basins, respectively. PSIAC estimates of total sediment yield are 1,200 tons/yr/mi2 for the Talofofo, 1,385 tons/yr/mi2 for the Ylig, and 1,210 tons/yr/mi2 for the Ugum basins. These values are comparable to estimates of sediment yields from several similar basins on Oahu, Hawaii. It appears that the PSIAC method can be a useful tool in estimating sediment yields in some tropical areas. (USGS)

Shade, P. J.

1983-01-01

261

Sediment deposition and selected water-quality characteristics in Cedar Lake and Lake Olathe, Northeast Kansas, 2000  

USGS Publications Warehouse

The Lake Olathe watershed, located in northeast Kansas, was investigated using bathymetric survey data and reservoir bottom-sediment cores to determine sediment deposition, water-quality trends, and transport of nutrients (phosphorus and nitrogen species), selected trace elements, selected pesticides, and diatoms as indicators of eutrophic (organic-enriched and depleted oxygen supply) conditions. To determine sediment deposition and loads, bathymetric data from Cedar Lake and Lake Olathe, both located in the Lake Olathe watershed, were collected in 2000 and compared to historical topographic data collected when the lakes were built. Approximately 338 acre-feet of sediment deposition has occurred in Cedar Lake since dam closure in 1938, and 317 acre-feet has occurred at Lake Olathe since 1956. Mean annual sediment deposition was 5.45 acre-feet per year (0.89 acre-feet per year per square mile) for Cedar Lake and 7.0 acre-feet per year (0.42 acre-feet per year per square mile) for Lake Olathe. Mean annual sediment loads for the two reservoirs were 9.6 million pounds per year for Cedar Lake and 12.6 million pounds per year for Lake Olathe. Mean concentrations of total phosphorus in bottom-sediment samples from Cedar Lake ranged from 1,370 to 1,810 milligrams per kilogram, and concentrations in bottom-sediment samples from Lake Olathe ranged from 588 to 1,030 milligrams per kilogram. The implication of large total phosphorus concentrations in the bottom sediment of Cedar Lake is that inflow into Cedar Lake is rich in phosphorus and that adverse water-quality conditions could affect water quality in downstream Lake Olathe through discharge of water from Cedar Lake to Lake Olathe via Cedar Creek. Mean annual phosphorus loads transported from the Lake Olathe watershed were estimated to be 14,700 pounds per year for Cedar Lake and 9,720 pounds per year for Lake Olathe. The mean annual phosphorus yields were estimated to be 3.74 pounds per acre per year for Cedar Lake and 0.91 pound per acre per year for Lake Olathe. Phosphorus yields in the Cedar Lake watershed were largest of the six Kansas impoundment watersheds recently studied. Concentrations of total ammonia plus organic nitrogen as nitrogen in bottom sediment increased from upstream to downstream in both Cedar Lake and Lake Olathe. Mean concentrations of total ammonia plus organic nitrogen as nitrogen (N) ranged from 2,000 to 2,700 milligrams per kilogram in bottom-sediment samples from Cedar Lake and from 1,300 to 2,700 milligrams per kilogram in samples from Lake Olathe. There was no statistical significance between total ammonia plus organic nitrogen as nitrogen and depth of bottom sediment. Concentrations of six trace elements in bottom sediment from Cedar Lake and Lake Olathe (arsenic, chromium, copper, lead, nickel, and zinc) exceeded the U.S. Environmental Protection Agency Threshold Effects Levels (TELs) sediment-quality guidelines for aquatic organisms in sediment except for one lead concentration. Probable Effects Levels (PELs) for trace elements, however, were not exceeded at either lake. Organochlorine and organophosphate insecticides were not detected in bottom-sediment samples from either Cedar Lake or Lake Olathe, but the acetanilide herbicides alachlor and metolachlor were detected in sediment from both lakes. The U.S. Environmental Protection Agency has not proposed TEL or PEL guideline concentrations for bottom sediment for any of the organophosphate, acetanilide, or triazine pesticides. The diatoms (microscopic, single-celled organisms) Cyclotella bodanica, an indicator of low organic-enriched water, and Cyclotella meneghiniana, an indicator of organic-enriched water, were both present in bottom sediment from Lake Olathe. The presence of both of these diatoms suggests varying periods of low and high eutrophication in Lake Olathe from 1956 to 2000. The concentrations of two species in bottom sediment from Cedar Lake, Aulacoseira cf alpigena and Cyclotella meneg

Mau, D. P.

2002-01-01

262

Hydrodynamic sorting and transport of terrestrially derived organic carbon in sediments of the Mississippi and Atchafalaya Rivers  

NASA Astrophysics Data System (ADS)

Over the course of two years, four cruises were conducted at varying levels of discharge in the lower Mississippi and Atchafalaya Rivers (MR and AR) where grab samples were collected from sand- and mud-dominated sediments. The tetramethylammonium hydroxide (TMAH) thermochemolysis method was used to determine sources of terrestrially derived organic carbon (OC) in these two sediment types, to examine the effects of hydrodynamic sorting on lignin sources in river sediments. Average lignin concentrations in the lower MR were 1.4 ± 1.1 mg gOC-1 at English Turn (ET) and 10.4 ± 27.4 mg gOC-1 at Venice. Using these concentrations, annual lignin fluxes to the Gulf of Mexico, from tidal and estuarine mud remobilization at ET and Venice, were 3.1 ± 2.5 × 105 kg and 11.4 ± 30.0 × 105 kg, respectively. Much of the lignin-derived materials in muddy sediments appeared to be derived from non-woody grass-like sources which should decay more quickly than the woody materials typically found in the sandy deposits. The average total OC% (1.93 ± 0.47) of English Turn sands yields an annual flux of 0.34 ± 0.09 × 109 kg. Lignin flux in the English Turn sands (3.6 ± 2.6 mg gC-1) using the numbers above would be 12.2 ± 9.4 × 105 kg. The extensive amounts of sand-sized woody materials (coffee-grinds) found in the sandy sediments in both the AR and MR are likely derived from woody plant materials. This is the first time it has been demonstrated that sandy sediments in the MR provide an equally important pathway (compared to muds) for the transport of terrestrially derived organic matter to the northern Gulf of Mexico. Using the AR average %OC in sand (1.16 ± 0.72), we estimated an annual flux of OC to the shelf of 0.13 ± 0.07 × 109 kg. Lignin flux for AR sands was estimated to be 12.4 ± 12.1 × 105 kg. Despite the high error associated with these numbers, we observe for the first time that the flux of lignin in sandy sediments in the AR to the northern Gulf of Mexico is comparable to that found in the MR. These results further support the likelihood of grain-size related hydrodynamic sorting of terrestrially derived organic carbon in the lower Mississippi and Atchafalaya Rivers, suggesting that there is a distinct sandy sediment organic fraction contributed by major rivers to the global carbon cycle.

Bianchi, Thomas S.; Galler, John J.; Allison, Mead A.

2007-06-01

263

Mercury Concentration and Monomethylmercury Production in Sediment: Effect of Dredged Sediment Reuse on Bioconcentration for Ragworms  

Microsoft Academic Search

The effect of dredged sediment reuse on the production and bioconcentration of monomethylmercury (MMHg) was investigated by\\u000a examining sediments and ragworms found in dredge material banks and surrounding sites in the Venice Lagoon, Italy. Total Hg\\u000a concentrations in the surface 20 cm of sediments were higher in the banks than in the surrounding sites, but MMHg concentrations\\u000a were similar, which suggests

Seunghee Han; Magali Porrachia; Elisa Volpato; Joris Gieskes; Dimitri D. Deheyn

2011-01-01

264

Estonian total ozone climatology  

NASA Astrophysics Data System (ADS)

The climatological characteristics of total ozone over Estonia based on the Total Ozone Mapping Spectrometer (TOMS) data are discussed. The mean annual cycle during 1979 2000 for the site at 58.3° N and 26.5° E is compiled. The available ground-level data interpolated before TOMS, have been used for trend detection. During the last two decades, the quasi-biennial oscillation (QBO) corrected systematic decrease of total ozone from February April was 3 +/- 2.6% per decade. Before 1980, a spring decrease was not detectable. No decreasing trend was found in either the late autumn ozone minimum or in the summer total ozone. The QBO related signal in the spring total ozone has an amplitude of +/- 20 DU and phase lag of 20 months. Between 1987 1992, the lagged covariance between the Singapore wind and the studied total ozone was weak. The spring (April May) and summer (June August) total ozone have the best correlation (coefficient 0.7) in the yearly cycle. The correlation between the May and August total ozone is higher than the one between the other summer months. Seasonal power spectra of the total ozone variance show preferred periods with an over 95% significance level. Since 1986, during the winter/spring, the contribution period of 32 days prevails instead of the earlier dominating 26 days. The spectral densities of the periods from 4 days to 2 weeks exhibit high interannual variability.

Eerme, K.; Veismann, U.; Koppel, R.

2002-02-01

265

Effect of algal bloom deposition on sediment respiration and fluxes  

Microsoft Academic Search

Using sediment cores collected in November 1989 from Aarhus Bight, Denmark, the fluxes of O2, SCO2 (total CO2), NH4+, NO3-+NO2-and DON (dissolved organic nitrogen) across the sediment-water interface were followed for 20 d in an experimental continous flow system. On day 7, phytoplankton was added to the sediment surface, to see the result of simulated algal bloom sedimentation. Benthic O2

L. S. Hansen; T. H. Blackburn

1992-01-01

266

A Site-Specific Evaluation of Mercury Toxicity in Sediment  

Microsoft Academic Search

.   A site-specific evaluation of mercury toxicity was conducted for sediments of the Calcasieu River estuary (Louisiana, USA).\\u000a Ten-day whole-sediment toxicity tests assessed survival and growth (dry weight) of the amphipods Hyalella azteca and Leptocheirus plumulosus under estuarine conditions (10 ppt salinity). A total of 32 sediment samples were tested for toxicity, including 14 undiluted\\u000a site sediment samples and 6

J. C. Sferra; P. C. Fuchsman; R. J. Wenning; T. R. Barber

1999-01-01

267

Multivariate analysis of potentially toxic metals in sediments of a tropical coastal lagoon.  

PubMed

Surface sediments collected from the Lagos Lagoon, Nigeria, and three adjoining rivers were analysed for their physicochemical properties and pseudo-total concentration of the potentially toxic metals (PTM) Cd, Cr, Cu, Pb and Zn. The concentration of the PTM varied seasonally and spatially. Odo-Iyaalaro was observed to be the most polluted river, with highest concentrations of 42.1 mg kg(-1), 102 mg kg(-1), 185 mg kg(-1), 154 mg kg(-1) and 1040 mg kg(-1) of Cd, Cr, Cu, Pb and Zn, respectively, while Ibeshe River was the least contaminated, apart from a site affected by Cu from the textile industry. Some of the sediments were found to be above the consensus-based probable effect concentrations and Dutch sediment guideline for metals. Overall metal concentrations were similar to those reported for other tropical lagoon and estuarine systems affected by anthropogenic inputs as a result of rapid urbanisation. Due to the large number of samples, principal component analysis was used to examine relationships within the data set. Generally, sediments collected during the dry season were observed to have higher concentration of PTM than those collected during the rainy season. This means that PTM could accumulate over a prolonged period and then be released relatively rapidly, on an annual basis, into tropical lagoon systems. PMID:22628107

Oyeyiola, A O; Davidson, C M; Olayinka, K O; Oluseyi, T O; Alo, B I

2012-05-25

268

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

2012-01-20

269

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

270

Sediment and Water Quality Response to Climate Change in Bai River Basin  

Microsoft Academic Search

Geographic informational system (GIS) and the Soil and Water Assessment Tool (SWAT) was used to simulate the transport of runoff, sediment, total nitrogen and total phosphorus into the Zhangjiafen stations. The main objective was to discuss climate change affecting on sediment and water quality. The results showed: The SWAT generally performs well and could accurately simulate monthly runoff, sediment, total

Qi Ji; Zheng Jiangkun; Yu Xinxiao

2011-01-01

271

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.

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

2011-01-01

272

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

NASA Astrophysics Data System (ADS)

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 0.05±0.13 ng/L; 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 in 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 6-36.4% of total lipids (CL+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 depth shallower 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 the 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.

Wei, Y.; Wang, J.; Liu, J.; Dong, L.; Li, L.; Wang, H.; Wang, P.; Zhao, M.; Zhang, C.

2011-12-01

273

Annual and seasonal variations of particle fluxes in the northwestern Pacific  

NASA Astrophysics Data System (ADS)

A moored time-series sediment trap was deployed at station FM 1 (13o31'N 136 o 03'E) of the northwestern Pacific from October 2007 to May 2011. Total mass fluxes varied from 2.35 to 31.1 mg m-2 day-1, showing a distinct seasonal variation with high fluxes in winter and low in summer. During the El Nino period, however, total mass fluxes were significantly reduced in winter, indicating that particle fluxes in the northwestern Pacific were considerably influenced by the El Nino. Organic carbon fluxes ranged from 0.13 to 4.61 mg m-2 day-1, comprising about 9.7% of total mass fluxes. Organic carbon fluxes showed a large annual variation, with higher fluxes in 2008. CaCO3 fluxes varied from 1.47 to 23.4 mg m-2 day-1, comprising 65.7% of total mass fluxes. CaCO3 fluxes displayed little annual and seasonal variations. Biogenic Si fluxes ranged from 0.04 to 2.07 mg m-2 day-1, comprising about 5.3% of total mass fluxes. Biogenic Si fluxes exhibited a large annual variation, with higher fluxes in 2008. Temporal variations of organic carbon fluxes were rather similar to those of biogenic Si fluxes, implying that the source of organic carbon is siliceous organisms.

Kim, Dongseon; Jeek Kim, Hyung

2013-04-01

274

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

275

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

276

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

277

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

278

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

279

Mathematical simulation of sediment and radionuclide transport in estuaries  

SciTech Connect

The finite element model LFESCOT (Flow, Energy, Salinity, Sediment and Contaminant Transport Model) was synthesized under this study to simulate radionuclide transport in estuaries to obtain accurate radionuclide distributions which are affected by these factors: time variance, three-dimensional flow, temperature, salinity, and sediments. Because sediment transport and radionuclide adsorption/desorption depend strongly on sizes or types of sediments, FLESCOT simulates sediment and a sediment-sorbed radionuclide for the total of three sediment-size fractions (or sediment types) of both cohesive and noncohesive sediments. It also calculates changes of estuarine bed conditions, including bed elevation changes due to sediment erosion/deposition, and three-dimensional distributions of three bed sediment sizes and sediment-sorbed radionuclides within the bed. Although the model was synthesized for radionuclide transport, it is general enough to also handle other contaminants such as heavy metals, pesticides, or toxic chemicals. The model was checked for its capability for flow, water surface elevation change, salinity, sediment and radionuclide transport under various simple conditions first, confirming the general validity of the model's computational schemes. These tests also revealed that FLESCOT can use large aspect ratios of computational cells, which are necessary in handling long estuarine study areas. After these simple tests, FLESCOT was applied to the Hudson River estuary between Chelsea and the mouth of the river to examine how well the model can predict radionuclide transport through simulating tidally influenced three-dimensional flow, salinity, sediment and radionuclide movements with their interactions.

Onishi, Y.; Trent, D.S.

1982-11-01

280

A century-scale record of the preservation of chlorophyll and its transformation products in anoxic sediments  

NASA Astrophysics Data System (ADS)

We have determined the chlorophyll pigment composition by liquid chromatography (LC) and LC/MS/MS in a 1.45-m long freeze core, representing 157 years of annually varved sedimentation, from Saanich Inlet, B.C, Canada. We investigated the very early diagenetic processes of chlorophyll a alteration in these anoxic sediments and the possible implications for palaeoproductivity studies. Excellent preservation of pigments is indicated by high total pigment concentrations, and the presence of labile compounds such as chlorophyllide a. The lack of systematic down core changes in both the total pigment concentration and the chlorin composition indicates that no detectable alteration of the pigment composition has occurred during the past 157 years. The sedimentary pigment composition is the result of processes occurring in the water column, or within few months after deposition. Chlorophyll derivatives corresponding to different diagenetic processes have distinct down core profiles. Profiles of compounds related to grazing activity steryl pyrophaeophorbide esters (SPE) and pyrophaeophytin a, are very similar. In contrast, dephytylated compounds (chlorophyllide a and phaeophorbide a), which are related to chlorophyllase activity during the degradation of ungrazed diatom cells, show an independent pattern. Quantifying pigment composition in Saanich Inlet sediments can help constrain processes regarding the transport of algal pigments to the sediments.

Villanueva, Joan; Hastings, David W.

2000-07-01

281

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

282

Health-Based Criteria for Sediment Disposal Options: A Case Study of the Port of New York\\/New Jersey  

Microsoft Academic Search

Approximately 4 million cubic yards of sediment are dredged annually from the Port of New York and New Jersey in order to maintain navigable channels. In many cases, the sediments contain elevated levels of numerous contaminants. The New York District of the U.S. Army Corps of Engineers and U.S. Environmental Protection Agency Region II employ a framework of sediment quality

Steave Su; Julie Rothrock; Leslie Pearlman; Brent Finley

2001-01-01

283

Empirical and conceptual modelling of the suspended sediment dynamics in a large tropical African river: the Upper Niger river basin  

Microsoft Academic Search

A 7-year sediment transport monitoring on the Upper Niger rivers was used to study the relationship between suspended sediment concentration and river discharge. During annual floods, these relationships show positive hysteresis. This paper presents the results of two models that estimate the time evolution of suspended sediment concentration using water discharge data only. The first model is based on a

C. Picouet; B. Hingray; J. C. Olivry

2001-01-01

284

Topography and Sedimentation Characteristics of the Squaw Creek National Wildlife Refuge, Holt County, Missouri, 1937-2002  

USGS Publications Warehouse

The Squaw Creek National Wildlife Refuge (hereafter referred to as the Refuge), located on the Missouri River floodplain in northwest Missouri, was established in 1935 to provide habitat for migratory birds and wildlife. Results of 1937 and 1964 topographic surveys indicate that sedimenta-tion, primarily from Squaw Creek and Davis Creek inflows, had substantially reduced Refuge pool volumes and depths. A study was undertaken by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, to quantify and spatially analyze historic rates of sedimentation in the Refuge and determine the surface elevations, depths, and pool capacities for selected managed pools from a 2002 survey.The 1937 to 1964 mean total sediment depo-sition, in the area corresponding to the 2002 sur-veyed pool area (about 4,900 acres), was 1.26 ft (feet), or 0.047 ft/yr (foot per year). Mean annual rates of deposition, by pool, from 1937 to 1964 varied from 0.016 to 0.083 ft/yr. From 1964 to 2002, the mean total sediment deposition in the 2002 surveyed pools was 0.753 ft, or 0.020 ft/yr. Therefore, the mean rate of sediment-depth accu-mulation from 1964 to 2002 was about 42 percent of the mean 1937 to 1964 rate, or a 58 percent reduction. Mean annual rates of deposition by pool from 1964 to 2002 varied from 0.010 to 0.049 ft/yr. Despite a substantial reduction in the average sediment accumulation rate for the Refuge, 5 of the 15 separate pools for which annual rates were calculated for both periods showed a small increase in the deposition rates of up to 0.008 ft/yr. Sediment deposits have resulted in a sub-stantial cumulative loss of volume in the Refuge pools since 1937. The 1937 to 2002 total sediment volume deposited in the 2002 surveyed pool area was about 9,900 acre-ft (acre-feet), or 152 acre-ft/yr (acre-feet per year). The volume of sediment deposited from 1937 to 1964 for these pools was about 6,200 acre-ft, or 230 acre-ft/yr. The volume deposited from 1964 to 2002 was about 3,700 acre-ft, or 97.3 acre-ft/yr.Bulk density values were determined from sediment cores collected from 22 sites in the Ref-uge and the bulk densities, along with sediment volumes, allowed for the calculation of sediment mass contributions to the Refuge. From 1937 to 2002, about 10,300,000 tons of sediment were deposited in the 2002 surveyed area, or 32.4 tons/acre/yr (tons per acre per year). The total computed mass of sediment deposited between 1937 and 1964 was about 6,510,000 tons, or an average of 49.1 tons/acre/yr. The total mass depos-ited from 1964 to 2002 in surveyed pools was about 3,830,000 tons, or an average of 20.5 tons/acre/yr. As with sediment thickness compari-sons, the rate of sediment mass deposition between 1964 to 2002 was about 42 percent of that from 1937 to 1964, or a 58 percent reduction.The greatest amounts of sediment deposition in the Refuge for 1937 to 2002 have been near the Squaw Creek and Davis Creek inflow spillway locations. Sediment depths in some areas near former inflow locations have exceeded 8 ft. Relo-cation of an inflow spillway effectively reduced additional sediment deposition at the original loca-tion, and caused increased sedimentation at the new inflow location. This is most clearly depicted in a pool located in the north section of the Refuge that directly received Squaw Creek inflows from 1937 to 1964 and had a mean deposition rate of 0.081 ft/yr reduced to 0.012 ft/yr, from 1964 to 2002, after inflows were redirected and erosion-management plans were implemented in the con-tributing basins.

Heimann, David C.; Richards, Joseph M.

2003-01-01

285

Sedimentation in the northern Gulf of California after cessation of the Colorado River discharge  

Microsoft Academic Search

The almost total elimination of sediment supply from the Colorado River has produced a condition of sediment starvation in the entire northern Gulf of California (NGC). Textural and mineralogical analyses of 114 surface sediment samples collected in the area show that this situation has promoted alternate sediment sources to become more important in supplying and controlling the compositional characteristics of

José D Carriquiry; Alberto Sánchez; Victor F Camacho-Ibar

2001-01-01

286

Alkaline Phosphatase Assay for Freshwater Sediments: Application to Perturbed Sediment Systems  

PubMed Central

The p-nitrophenyl phosphate hydrolysis-phosphatase assay was modified for use in freshwater sediment. Laboratory studies indicated that the recovery of purified alkaline phosphatase activity was 100% efficient in sterile freshwater sediments when optimized incubation and sonication conditions were used. Field studies of diverse freshwater sediments demonstrated the potential use of this assay for determining stream perturbation. Significant correlations between phosphatase and total viable cell counts, as well as adenosine triphosphate biomass, suggested that alkaline phosphatase activity has utility as an indicator of microbial population density and biomass in freshwater sediments.

Sayler, Gary S.; Puziss, Marla; Silver, Martin

1979-01-01

287

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

2013-04-16

288

Totally James  

ERIC Educational Resources Information Center

|This article presents an interview with James Howe, author of "The Misfits" and "Totally Joe". In this interview, Howe discusses tolerance, diversity and the parallels between his own life and his literature. Howe's four books in addition to "The Misfits" and "Totally Joe" and his list of recommended books with lesbian, gay, bisexual,…

Owens, Tom

2006-01-01

289

Totally James  

ERIC Educational Resources Information Center

This article presents an interview with James Howe, author of "The Misfits" and "Totally Joe". In this interview, Howe discusses tolerance, diversity and the parallels between his own life and his literature. Howe's four books in addition to "The Misfits" and "Totally Joe" and his list of recommended books with lesbian, gay, bisexual, transgender,…

Owens, Tom

2006-01-01

290

Dissolved and particulate carbohydrates in contrasting marine sediments  

NASA Astrophysics Data System (ADS)

Dissolved and particulate carbohydrates were examined in contrasting Chesapeake Bay (estuarine) and mid-Atlantic shelf/slope break (continental margin) sediments. Particulate carbohydrates (PCHOs) represented ˜5-9% of the total sediment particulate organic carbon (POC), and PCHO remineralization appeared to be a similar fraction of total sediment carbon oxidation (or C ox). When these results are compared with results from other coastal sediments and a pelagic turbidite, PCHO remineralization (as a percentage of C ox) did not vary by more than a factor of ˜2-3 over a 3-4 order of magnitude range in C ox values. The causes of this are not well understood, but may be related to specific effects associated with the remineralization of highly altered organic matter mixtures under aerobic conditions. Dissolved carbohydrates (DCHOs) in these sediment pore waters ranged from ˜30 to 400 ?M, increased with depth in a manner similar to total DOC, and represented ˜10 to 55% of pore water DOC. In Chesapeake Bay sediments this percentage decreased with sediment depth, while in these continental margin sediments it was constant (upper 30 cm). Of the DCHOs in these pore waters ˜30 to 50% could be identified as individual aldoses (monomeric neutral sugars), and total aldose yields (individual aldoses as a percentage of total DOC) were higher in these continental margin sediment pore waters (>9%) than they were in the estuarine sediment pore waters (<5%). A comparison of DCHO and PCHO concentrations in these sediments indicates that their concentrations are uncoupled, and that pore water DCHO concentrations are primarily controlled by sediment remineralization processes. Pore water DCHOs appeared to be preferentially found in the high molecular weight (HMW) DOC pool, and likely occur as some of the initial HMW intermediates produced and consumed during sediment POC remineralization. These results also support past suggestions about the differing controls on carbon remineralization processes in continental margin versus estuarine sediments.

Burdige, D. J.; Skoog, A.; Gardner, K.

2000-03-01

291

Availability of organic chemicals for biodegradation in settled bottom sediments.  

PubMed

Biodegradation rates for dodecyltrimethylammonium chloride (TMAC), a quaternary ammonium compound, and phenol were measured in settled sediments to determine if adsorbed chemicals were directly available for biodegradation by sediment-associated bacteria. In settled sediment cores, biodegradation rates for TMAC, which is charged at environmental pH, was a function of the amount of unadsorbed chemical; adsorbed material was not directly degraded by the sediment-associated bacteria. However, the rate of biodegradation of adsorbed phenol, a relatively hydrophobic and neutral chemical, was apparently a function of the total concentration of material present, suggesting that at least a fraction of the adsorbed material was directly degraded. These results indicate that chemical structure and, possibly, the mechanism of adsorption may influence biodegradation in sediments. Studies on TMAC biodegradation in completely mixed sediment/water slurries (up to 10 g/liter sediment) showed that TMAC biodegradation in slurries differed from that in settled sediments. Biodegradation in slurries was a function of the total amount of material present, both adsorbed and unadsorbed. These results suggest that biodegradation in settled sediments may be influenced by high concentrations of sediment present and/or the lack of mixing. Thus mixed, low-sediment-level slurries may not be realistic surrogates for modeling biodegradation processes in settled bottom sediments. PMID:3359954

Shimp, R J; Young, R L

1988-02-01

292

Transport simulation of sorptive contaminants considering sediment-associated processes  

NASA Astrophysics Data System (ADS)

Sediment-associated processes, such as sediment erosion, deposition, and pore water diffusion/advection affect sorptive contaminant transport. By considering these processes, we developed an equation to simulate contaminant transport. Erosion and deposition processes are considered as erosion and deposition fluxes of sediment, and adsorption-desorption processes of contaminants by sediment are simulated using the Langmuir Equation. Pore water diffusion is calculated based on the contaminant concentration gradient across the sediment-water interface. Pore water advection is estimated using pore water contained in the sediments of erosion flux. The equation is validated to simulate total phosphorus concentrations in Guanhe estuary in the northern Jiangsu, China. The simulated total phosphorus concentrations show better agreement with field observations compared to estimations that do consider sediment-associated processes.

Li, Ruijie; Lu, Shasha; Zheng, Jun

2012-07-01

293

Sources and transport of sediment, nutrients, and oxygen-demanding substances in the Minnesota River basin, 1989-92  

USGS Publications Warehouse

The Minnesota River, 10 major tributaries, and 21 springs were sampled to determine the sources and transport of sediment, nutrients, and oxygen- demanding substances. The study was part of a four-year assessment of non-point source pollution in the Minnesota River Basin. Runoff from tributary watersheds was identified as the primary source of suspended sediment and nutrients in the Minnesota River mainstem. Suspended-sediment, phosphorus, and nitrate concentrations were elevated in all major tributaries during runoff, but tributaries in the south-central and eastern part of the basin produce the highest annual loading to the mainstem because of higher annual precipitation and runoff in that part of the basin. Particle-size analyses showed that most of the suspended sediment in transport consisted of silt- and clay-size material. Phosphorus enrichment was indicated throughout the mainstem by total phosphorus concentrations that ranged from 0.04 to 0.48 mg/L with a median value of 0.22 mg/L, and an interquartile range of 0.15 to 0.29 mg/L. Nitrate concentrations periodically exceeded drinking water standards in tributaries draining the south-central and eastern part of the basin. Oxygen demand was most elevated during periods of summer low flow. Correlations between levels of biochemical oxygen demand and levels of algal productivity suggest that algal biomass comprises much of the oxygen-demanding material in the mainstem. Transport of sediment, nutrients, and organic carbon within the mainstem was found to be conservative, with nearly all tributary inputs being transported downstream. Uptake and utilization of nitrate and orthophosphorus was indicated during low flow, but at normal and high flow, inputs of these constituents greatly exceeded biological utilization.

Payne, G. A.

1994-01-01

294

Sediment management in sustainable urban drainage system ponds.  

PubMed

Since removal and disposal of sustainable urban drainage system (SUDS) sediment can incur high maintenance costs, assessments of sediment volumes, quality and frequency of removal are required. Sediment depth and quality were surveyed annually from 1999-2003 in three ponds and one wetland in Dunfermline, Scotland, UK. Highest sediment accumulation occurred in Halbeath Pond, in the most developed watershed and with no surface water management train. From comparison of measured potentially toxic metal concentrations (Cd, Cr, Cu, Fe, Ni, Pb, Zn) with standards, the average sediment quality should not impair aquatic ecosystems. 72-84% of the metal flux into the SUDS was estimated to be associated with coarse sediment (> 500 microm diameter) suggesting that management of coarse sediment is particularly important at this site. The timing of sediment removal for these SUDS is expected to be determined by loss of storage volume, rather than by accumulation of contaminants. If sediment removal occurs when 25% of the SUDS storage volume has infilled, it would be required after 17 years in Halbeath Pond, but only after 98 years in Linburn Pond (which has upstream detention basins). From the quality measurements, sediment disposal should be acceptable on adjacent land within the boundaries of the SUDS studied. PMID:16838706

Heal, K V; Hepburn, D A; Lunn, R J

2006-01-01

295

The biogeography of major diatom taxa in Southern Ocean sediments  

Microsoft Academic Search

Diatoms from 228 Southern Ocean core-top sediment samples were examined to determine the geographic distributions of 32 major diatom species\\/taxa preserved in the sediments of three zonally-distinct regions; Sea Ice, Open Ocean and the Tropical\\/Subtropical. In the first of three papers, 14 species\\/taxa occurring in the region where sea ice covers the ocean surface on an annual basis are geographically

Leanne K. Armand; Xavier Crosta; Oscar Romero; Jean-Jacques Pichon

2005-01-01

296

Roles and Patterns of Hurricane Sedimentation in an Estuarine Marsh Landscape  

NASA Astrophysics Data System (ADS)

The passage of hurricane Andrew across the Louisiana coastal zone in 1992 was used to study the effects of hurricane sedimentation on estuarine marshes. (1) The thickness and nutrient content of hurricane sediments, (2) the composition of hurricane sediments relative to pre-existing sediments, and (3) the relationship between hurricane sedimentation and small-scale heterogeneity in the emergent plant community were investigated. Vertical accretion resulting from the hurricane was 4-11 times greater than the long-term (30 year) annual rate. The hurricane sediments will be within the root zone of emergent vegetation for 35-50 years, depending on the local marsh vertical accretion rate. Element concentration, organic matter content, and texture of hurricane sediments varied over a wide area, which suggested that hurricane sediments did not originate from a common sediment pool. The concentration of most elements analysed did not differ between hurricane sediments and pre-existing sediments, which suggested that hurricane sediments originated primarily from the same local bays and lakes that provide material for other sedimentation events. Hurricane sediments were thicker in Juncus roemerianusstands than in surrounding Spartina alterniflorastands. Greater hurricane sedimentation in J. roemerianusstands was attributed to greater stem density there and may help maintain plant community heterogeneity if J. roemerianusis less flood-tolerant than S. alterniflora, as previous work suggests. Previous studies have noted the effect of environmental gradients on plant species distribution, but our data indicate that plant species can also generate different environmental conditions associated with their distribution.

Nyman, J. A.; Crozier, C. R.; DeLaune, R. D.

1995-06-01

297

Sediment characteristics of small streams in southern Wisconsin, 1954-59  

USGS Publications Warehouse

The results of investigations of the sediment and water discharge characteristics of Black Earth Creek, Mount Vernon Creek, and Yellowstone River from 1954 to 1959 and Dell Creek for 1958 and 1959 indicate large differences in annual runoff and sediment yields. The suspended-sediment discharge of Black Earth Creek averaged 3,260 tons per year or 71 tons per square mile : the annual yields ranged from 27 to 102 tons per square mile. The annual suspended-sediment yield of Mount Vernon Creek ranged from 48 to 171 tons per square mile and averaged 96 tons per square mile. The maximum daily discharge was 1,120 tons on April 1, 1960, during a storm which produced 67 percent of the suspended load for that water year and exceeded the discharge for the preceding 3 years. The sediment discharge of the Yellowstone River averaged 6,870 tons per year or 236 tons per square riffle. The maximum daily sediment discharge, 3,750 tons on April 1, 1959, occurred during a 14-day period of high flow during which the sediment discharge was 15,480 tons. In 1958 and 1959, Dell Creek had suspended-sediment yields of 4.7 and 26 tons per square mile of drainage area. The suspended sediment transported by Black Earth and Mount Vernon Creeks is about two-thirds clay and one-third silt. For Yellowstone River the particle-size distribution of the suspended sediment ranged from three-fourths clay and one-fourth silt during periods of low sediment discharge to one-third clay and two-thirds silt during high sediment discharges. For Dell Creek nearly all of the suspended sediment is clay, but the bed load is sand. The mean sediment concentration of storm runoff averaged two to three times more in the summer than in the winter. No significant changes with time occurred in the relation between storm runoff and sediment yield.

Collier, Charles R.

1963-01-01

298

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

299

Sediment yield response to sediment reduction strategies ...  

Treesearch

Description: For the past decade, the productive forestlands now owned and ... according to voluntary agreements and regulatory requirements of state and federal ... Intensive watershed and property-wide studies of sediment processes within the ... documented significant sediment impacts from past management activities.

300

Mechanics of Calcareous Sediments.  

National Technical Information Service (NTIS)

The paper summarizes the results of a research program into the behavior and engineering properties of marine calcareous sediments, and the behavior of foundations in such sediments. The following aspects are addressed: (1) the strength and deformation pr...

H. G. Poulos

1989-01-01

301

ESR (Erythrocyte Sedimentation Rate) Test  

MedlinePLUS

... rate; Sedimentation rate; Westergren sedimentation rate Formal name: Erythrocyte Sedimentation Rate Related tests: C-reactive protein (CRP) ; ... None The Test Sample What is being tested? Erythrocyte sedimentation rate (ESR) is an indirect measure of ...

302

Stable lead isotopes and lake sediments—a useful combination for the study of atmospheric lead pollution history  

Microsoft Academic Search

Analysis of stable lead isotopes and lead concentrations in lake-sediment deposits, not least in varved (annually-laminated) sediments, is a useful method to study lead pollution history. This paper presents details from a study of 31 lakes in Sweden. Using a strong acid digestion of sediment samples and ICP-MS analyses, we have found that Swedish lake sediments have a high natural

I. Renberg; M.-L. Brännvall; R. Bindler; O. Emteryd

2002-01-01

303

Interlaminated ice-proximal glacimarine sediments in Muir Inlet, Alaska  

USGS Publications Warehouse

Muir Inlet in Glacier Bay, Alaska, is a glacial fjord receiving a tremendous volume of sediment annually. The rate of sediment accumulation is greatest proximal to Muir Glacier (about 9 m yr-1) and decreases away from the glacier. The primary sediment sources are meltwater streams discharging at subglacial and ice-marginal positions to form overflows, interflows, and underflows (continuous turbidity currents). Overflows and interflows interact with diurnal tidal currents and their volume and sediment concentration varies diurnally and annually with meltwater discharge. These effects produce cyclic deposits of a thin fine-grained sand or silt lamina that grades normally to a thicker poorly to very poorly sorted mud lamina. This lamina couplet is termed a cyclopel. Underflows are suggested to occur in this glacimarine environment because of conditions unique to subglacial fluvial systems. Underflow deposits occur only in proximal positions (177 ??m) is ubiquitous, though low (<5% by weight), and occurs as isolated particles, frozen pellets, or as lenses that in cores may have a lamina appearance. Proximally, ice-rafted debris is difficult to identify because proximal sediment is often as coarse-grained. Deposited sediment may be reworked by tidal currents, and sediment gravity flows. Depositional processes operating in Muir Inlet produce interlaminated sand/silt/clay that characterizes sediment proximal to a glacier and fines seaward to mud. Sediment is classified into one of three sediment types: 1. (1) Type I sediment is very fine grained (mean 8.65-7.17 ??), low in sand (0.1-11.2%), and very poorly to poorly sorted. It is the dominant sediment type in Muir Inlet, and is transported by plumes and deposited by suspension settling. 2. (2) Type II sediment is fine- to coarse-grained (mean 6.70-3.12 ??), low to high in sand (5.1-86.6%), and very poorly to moderately sorted. It represents reworked sediment, proximal plume deposits, or coarse-grained laminae of cyclopels. 3. (3) Type III sediment is coarse-grained (mean 3.89-2.38 ??), high in sand (58.0-100.0%), and poorly to well sorted. It is deposited by sediment gravity flows or underflows. ?? 1984.

Mackiewicz, N. E.; Powell, R. D.; Carlson, P. R.; Molnia, B. F.

1984-01-01

304

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

305

Benthic respiration measured by total carbonate production  

Microsoft Academic Search

Abstract The suitability of total carbonate production,instead of oxygen consumption,as a measure,of benthic respiration has been investigated. In situ fluxes of total carbonate, oxygen, calcium, total alkalinity, nutrients, and sulfide across the sediment-water interface were measured in diver- operated benthic flux chambers. Two chambers,were run in parallel to test the influence of oxygen and pH levels on total carbonate production.

LEIF G. ANDERSON; PER O. J. HALL; ÅKE IVERFELDT; MICHIEL M. RUTGERS VAN DER LOEFF; BJØRN SUNDBY; STIG F. G. WESTERLUND

1986-01-01

306

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

PubMed

Land cover changes around river basins have caused serious environmental degradation in global surface water areas, in which the direct monitoring and numerical modeling is inherently difficult. Prediction of pollutant loads is therefore crucial to river environmental management under the impact of climate change and intensified human activities. This research analyzed the relationship between land cover types estimated from NOAA Advanced Very High Resolution Radiometer (AVHRR) imagery and the potential annual pollutant loads of river basins in Japan. Then an empirical approach, which estimates annual pollutant loads directly from satellite imagery and hydrological data, was investigated. Six water quality indicators were examined, including total nitrogen (TN), total phosphorus (TP), suspended sediment (SS), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Dissolved Oxygen (DO). The pollutant loads of TN, TP, SS, BOD, COD, and DO were then estimated for 30 river basins in Japan. Results show that the proposed simulation technique can be used to predict the pollutant loads of river basins in Japan. These results may be useful in establishing total maximum annual pollutant loads and developing best management strategies for surface water pollution at river basin scale. PMID:19844047

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

2009-01-01

307

A Comparative Study of Organic Carbon and Nutrients in Lake Sediment.  

National Technical Information Service (NTIS)

Sediment cores were obtained from Couer d'Alene, Liberty, Williams, Silver and Capitol Lakes in the Washington-Idaho region. A procedure was developed to analyze the total organic carbon (TOC) of sediment using the Oceanographic International Corporation ...

D. E. Anderson

1975-01-01

308

Organic Phosphorus in Marine Sediments: Chemical Structure, Diagenetic Alteration, and Mechanisms of Preservation.  

National Technical Information Service (NTIS)

Phosphorus, an essential nutrient, is removed from the oceans only through burial with marine sediments. Organic phosphorus P(org) constitutes an important fraction (Ca. 25%) of total-P in marine sediments. However, given the inherent lability of primary ...

K. L. Laarkamp

2000-01-01

309

Total glossectomy.  

PubMed

Forty-five patients had a "total" glossectomy for initial advanced tongue carcinoma or for recurrent carcinoma. Forty percent of the patients (18) had a total laryngectomy at the time of glossectomy. Forty-nine percent of the patients (22) had either a lateral or anterior mandibulectomy at the time of glossectomy. Seventy-one percent of the patients (15 of 21) who had an intact larynx and 12.5 percent who had laryngectomy (3 of 24) had some degree of useful speech. Thirty-one percent of the patients (14 of 45) had no problems in deglutition whereas 53 percent of the patients (24) needed a nasogastric tube, 4 patients inserted the feeding tube themselves, 2 had a cervical esophagostomy, and 1 had a special prosthesis for feeding purposes. Thirty-seven percent of the patients (10 of 27) had considerable aspiration problems. Twenty-two percent (6 patients) needed a laryngectomy, and 7.5 percent (2 patients) needed a cervical esophagostomy to prevent further problems. Seven and one-half percent of the patients (2) succumbed to serious pulmonary infection. In this study, total glossectomy had a salvage rate of 65 percent at 6 months postoperatively, 27.5 percent at 1 year, 25 percent at 2 years, 25 percent at 3 years, 20 percent at 5 years, and 10 percent at 10 years. PMID:6625097

Razack, M S; Sako, K; Bakamjian, V Y; Shedd, D P

1983-10-01

310

MISSING THE STORM: PREDICTING SEDIMENT EXPORT FROM BASEFLOW CONDITIONS IN LOW-ORDER LAKE SUPERIOR WATERSHEDS  

EPA Science Inventory

Midwestern streams export most of their annual sediment load during snowmelt and rainfall events, however measuring sediment export at peak stream discharges is not always possible. Watershed-level, riparian, and instream data were collected from 48 second and third order Lake S...

311

In-situ reflectance spectroscopy - analysing techniques for high-resolution pigment logging in sediment cores  

Microsoft Academic Search

The temporal resolution of marine proxy data is limited by analytically required sample size. We present in-situ reflectance spectroscopy techniques (usually applied in remote sensing) to analyse the organic fraction of marine and terrestrial sediment. From absorption band depths, photosynthesis pigment variations are derived for sediments from the upwelling region off Peru, where productivity is related to the annual variability

Bert Rein; Frank Sirocko

2002-01-01

312

The potential for paleolimnology to determine historic sediment delivery to rivers  

Microsoft Academic Search

Establishment of water quality criteria to guide catchment sediment management is required by the European Union (EU) Water Framework Directive. The topic, however, is hotly contested among scientists and policy makers. Existing legislation with regard to fine sediment was set by the EU Freshwater Fish Directive. Its guideline, i.e. mean annual suspended sediment concentration, is 25 mg l?1. Such a static target

I. D. L. Foster; A. L. Collins; P. S. Naden; D. A. Sear; J. I. Jones; Y. Zhang

2011-01-01

313

Impact of urbanization on suspended sediment and organic matter fluxes from small catchments in Tahiti  

NASA Astrophysics Data System (ADS)

This study provides an initial characterization of pollution associated with storm runoff in Tahiti. A thousand floodwater samples were collected from three representative catchments and subsequently analysed. The main pollution parameters chosen were total suspended sediment (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total nitrogen (TN) and Total Phosphorus (TP). First, organic pollution appeared to be related closely to sediment, thus TSS could be used as a global indicator. Next, regression models between an event's TSS load and its hydrological characteristics were used to obtain annual load estimates. Great interannual variability was found to be strongly influenced by the few major floods that occur during the rainy season. Our results also emphasize the importance of the impact of urbanization on solid catchment exportation: from 60 TSS t/km2/year in a natural forested catchment, fluxes reached more than 700 TSS t/km2/year during preparatory urbanization earthworks before stabilizing at 140 TSS t/km2/year in a consolidated urbanized area. Clearly, runoff effects need to be taken into consideration for effective urban planning and for the preservation of the coastal environment in Tahiti.

Wotling, G.; Bouvier, Ch.

2002-06-01

314

[Spatial distribution and contamination evaluation of heavy metals in the intertidal surface sediments of Eastern Chongming].  

PubMed

Using the ArcGIS geostatistical analysis module, this work investigated the spatial distribution pattern of heavy metals (Cu, Pb, Zn, Cr, Cd) and their deposition fluxes in the intertidal surface sediments of Eastern Chongming based on the analysis of grain size, heavy metal concentrations and organic carbon content. The spatial interpolation (Kriging) was performed to estimate the deposition fluxes, and the contamination status of heavy metals was evaluated using geoaccumulation index and potential ecological risk index. The results showed that the average contents of Cu, Pb, Zn, Cr and Cd were 42, 27, 69, 71 and 0.23 microg x g(-1), respectively, all of which exceeded the background value in the Shanghai tidal flat. The contents of heavy metals showed a landward as well as northward increasing trend due to the influences of sediment grain size and organic carbon content. The annual deposition of Cu, Pb, Zn, Cr and Cd in Eastern Chongming were 187, 121, 395, 312 and 1.04 t, respectively; the total deposition flux of these heavy metals was 11 g x (m2 x a)-1. Although the overall contamination level of heavy metals in Eastern Chongming was relatively low, Cd, Pb and Cu had a potential pollution threat to the sediment environment. PMID:23002615

Li, Ya-Juan; Yang, Shi-Lun; Hou, Li-Jun; Zhou, Ju-Zhen; Liu, Ying-Wen

2012-07-01

315

Geochemistry of Marine Sediments  

NASA Astrophysics Data System (ADS)

David J. Burdige; Princeton University Press; ISBN-13: 978-0-691-09506X; xviii + 630 pp.; 2006; $85.00 The uplift of rocks above sea level on the Earth's surface over geologic time produces material that can be altered into soils and sediments by weathering processes. Over time, a fraction of sediments are sequestered in ocean basins, with most of it stored in the coastal margin. Sediments produced from weathering of igneous, metamorphic, and sedimentary rocks are transported primarily to the oceans through the world's river systems. The storage of organic matter in marine sediments is largely dependent upon the amount of early diagenesis (processes that alter the structure, texture, and mineralogy of a sediment, turning it progressively into solid hard rock; early diagenesis occurs immediately after deposition or burial of the sediment) that occurs in the upper sediments, which is controlled largely by the ``quality'' of organic detrital inputs and redox conditions of the sedimentary environment.

Bianchi, Thomas S.

2007-11-01

316

Experimental study on phosphorus release from sediments of shallow lake in wave flume  

Microsoft Academic Search

Influence of wave on sediment resuspension and nutrients release from sediments, collected from Lake Taihu and Lake Chaohu,\\u000a was studied in flume experiments. Under strong-wave conditions, concentrations of suspended solids (SS), total phosphorus\\u000a (TP) and dissolved total phosphorus (DTP) in overlying water were increased significantly following the sediments re-suspension.\\u000a During the experiments on sediments of Lake Taihu and Lake Chaohu,

Xiaojing Sun; Guangwei Zhu; Liancong Luo; Boqiang Qin

2006-01-01

317

Fugacity approach to evaluate the sediment-water diffusion of polycyclic aromatic hydrocarbons.  

PubMed

Diffusion is an important process for sediment-water exchange and plays a vital role in controlling water quality. Fugacity fraction (ff) was used to estimate the sediment-water diffusion of polycyclic aromatic hydrocarbons (PAHs) between seawater and surficial sediment. A total of 33 surface sediment and sea water samples were collected concurrently from the northeast coastal area in China and 25 PAHs were analyzed including the alkylated and chlorated PAHs. Fugacity fraction was calculated based on the PAH concentrations in water and sediment, octanol-water partition coefficient of PAHs, organic matter content in sediment, and density of sediment. The calculated results showed that ff increased with decreasing molecular weight of PAHs. The low molecular weight PAHs (2-3 rings) transferred from sediment to water and the sediment acted as a secondary source to the water. The medium molecular weight PAHs (4-5 rings) were close to the sediment-water equilibrium and the transfer tendency shifted between sediment and water. The high molecular weight PAHs (5-6 rings) transferred from water into sediment and the sediment acted as a sink. Soot carbon and the difference of PAH concentrations between sediment and water were found to be important factors affecting the sediment-water diffusion. This study provided new insight into the process of sediment-water diffusion, which has a great influence on the quality of water, especially in severely-polluted sediment areas. PMID:21552633

Wang, De-Gao; Alaee, Mehran; Byer, Jonathan; Liu, Yong-Jun; Tian, Chong-Guo

2011-05-09

318

Middlesex Sampling Plant and Middlesex Municipal Landfill. Annual site environmental report, calendar year 1985. Formerly Utilized Sites Remedial Action Program (FUSRAP). [FUSRAP  

SciTech Connect

The monitoring program at the Middlesex Sampling Plant (MSP) and Middlesex Municipal Landfill (MML) measures uranium and radium concentrations in surface water, groundwater, and sediment; radon gas concentrations in air; and external gamma radiation dose rates. Potential radiation doses to the public are also calculated. During 1985, the highest annual average radon levels in air at the MML and MSP were 10% and 17%, respectively, of the Derived Concentration Guides (DCG). The highest annual average gamma dose rate at the MSP was 167 mrem/y; at the MML the highest annual average dose rate was 13 mrem/y. The highest average annual concentrations of uranium in surface water monitored at the MSP and MML were 13% and 1%, respectively, of the DOE DCG. The highest annual average concentrations of /sup 226/Ra in surface water were 3.3 and 0.8%, respectively, of the applicable DOE DCG. The highest annual average uranium concentration in groundwater at the MSP was about 9% of the DCG; the highest /sup 226/Ra concentration was 0.7% of the respective DCG. The corresponding values for the MML were 0.5 and 3.3%. The highest annual average concentrations of uranium and /sup 226/Ra in sediments at the MSP were 7.7 and 3.5 pCi/g, respectively. The highest uranium concentration at the MML was 3.3 pCi/g, while the highest /sup 226/Ra concentration was 0.7 pCi/g. The calculated total radiation dose to the maximally exposed individual at the MSP, considering several pathways, was 10.5 mrem or 11% of the radiation protection standard; at the MML, it was 0.14 mrem or less than 1% of the radiation protection standard.

Not Available

1986-08-01

319

Recent and Past High Resolution Organic Sedimentation in an Upwelling Cell of Humboldt Current System; Mejillones bay, Northern Chile.  

NASA Astrophysics Data System (ADS)

In this study, we present information of annual hydrographic variability, surface sediments distribution and one sedimentary core analyses to reconstruct the past 200 years of oceanographic history of Mejillones, focusing on the productivity and oxygenation factors. Spatial differences in surface water productivity were evaluated using periodical ^13C measurements of dissolved inorganic carbon. The organic composition of the superficial sediment, analyzed by statistical approach, reflects the three principal zones identified by their degree of bottom oxygenation. The oxic coastal zone preserves principally non-metabolizable organic matter with high Oxygen Index (OI) and low Hydrogen Index (HI), total carbon (TC), total organic carbon (TOC) and nitrogen content (NT). In this area, the organic fraction is dominated by dispersed amorphous organic matter. This suggests an environment where most of metabolizable organic matter has been degraded within the water column and/or at the benthic surface sediments. The microxic hemipelagic zone located deeper than 65 meters, is marked by low OI values and high HI, TC, TOC and NT values. Palynofacies study of sediments collected in this zone reveals the presence of abundant agglomerated amorphous organic matter. All these results suggest high primary productivity and increased flocculation (self-sedimentation) of organic matter, which partly permitted its preservation. The sedimentary organic matter deposited in the transitional disoxic zone, located between the costal and hemipelagic areas, is characterized by the same values of TC and NT than the microxic zone, but do not present the same petrographical parameters. Based on this calibration study, we identified three differents periods in the oceanographic evolution of the embayment, during the past 200 years. Before the nineteenth century, the sedimentary record suggests an enhanced oxygenation and/or depleted productivity Abrupt alternations of the two oceanographic state described previously seem to have occurred during the nineteenth century. During the major part of the twentieth century the sedimentary record indicates a higher primary productivity coupled to an intensification of microxic/anoxic condition of the water column.

Jorge, V.; Abdel, S.; Luc, O.; Gabriel, V.; Catherine, P.

2005-12-01

320

Rates of sediment supply and sea-level rise in a large coastal lagoon  

USGS Publications Warehouse

Laguna Madre, Texas, is 3-7 km wide and more than 190 km long, making it one of the longest lagoons in the world. The lagoon encompasses diverse geologic and climatic regions and it is an efficient sediment trap that accumulates clastic sediments from upland, interior, and oceanic sources. The semi-arid climate and frequent tropical cyclones historically have been responsible for the greatest volume of sediment influx. On an average annual basis, eolian transport, tidal exchange, storm washover, mainland runoff, interior shore erosion, and authigenic mineral production introduce approximately one million m3 of sediments into the lagoon. Analyses of these sediment transport mechanisms and associated line sources and point sources of sediment provide a basis for: (1) estimating the long-term average annual sediment supply to a large lagoon; (2) calculating the average net sedimentation rate; (3) comparing introduced sediment volumes and associated aggradation rates with observed relative sea-level change; and (4) predicting future conditions of the lagoon. This comparison indicates that the historical average annual accumulation rate in Laguna Madre (<1 mm/yr) is substantially less than the historical rate of relative sea-level rise (~4 mm/yr). Lagoon submergence coupled with erosion of the western shore indicates that Laguna Madre is being submerged slowly and migrating westward rather than filling, as some have suggested. (C) 2000 Elsevier Science B.V.

Morton, R. A.; Ward, G. H.; White, W. A.

2000-01-01

321

St. Louis Airport Site. Annual site environmental report, calendar year 1985. Formerly Utilized Sites Remedial Action Program (FUSRAP). Revision 1  

SciTech Connect

During 1985, the environmental monitoring program was continued at the St. Louis Airport Site (SLAPS) in St. Louis County, Missouri. The ditches north and south of the site have been designated for cleanup as part of the Formerly Utilized Sites Remedial Action Program (FUSRAP). The monitoring program at the SLAPS measures radon gas concentrations in air; external gamma radiation dose rates; and uranium, thorium, and radium concentrations in surface water, groundwater, and sediment. Potential radiation doses to the public are also calculated. Because the site is not controlled or regulated by the DOE, the DOE Derived Concentration Guides (DCGs) are not applicable to SLAPS, but are included only as a basis for comparison. The DOE DCGs and the DOE radiation protection standard have been revised. (Appendix B). During 1985, annual average radon levels in air at the SLAPS were below the DCG for uncontrolled areas. External gamma monitoring in 1985 showed measured annual gamma dose rates ranging from 3 to 2087 mrem/y, with the highest value occurring in an area known to be contaminated. The calculated maximum dose at the site boundary, assuming limited occupancy, would be 6 mrem/y. Average annual concentrations of /sup 230/Th, /sup 226/Ra, and total uranium in surface waters remained below the DOE DCG. The on-site groundwater measurements showed that average annual concentrations of /sup 230/Th, /sup 226/Ra and total uranium were within the DOE DCGs. Although there are no DCGs for sediments, all concentrations of total uraniu, /sup 230/Th, and /sup 226/Ra were below the FUSRAP Guidelines.

Not Available

1986-09-01

322

Sediment delivery from agricultural land to rivers via subsurface drainage  

NASA Astrophysics Data System (ADS)

Diffuse sources of sediment and sediment-associated nutrients are of increasing environmental concern because of their impacts on receiving water courses. The aim of the research reported here was to monitor the outflow from four field (land) drains at two farms in the English Midlands in order to estimate the quantity of sediment delivered to the local rivers and the most likely sources and processes involved. A multiparameter sediment unmixing model was employed, using environmental magnetic, geochemical and radionuclide tracers in order to determine the most likely origin of sediments transported through the drains. Results demonstrated that there was a generally linear relationship between drainflow sediment loss and drainflow volume and that the majority (>70%) of the sediment exported from the drains was derived from topsoil. Macropore flow through heavily cracked soils is supported by the data to be the most likely means of sediment delivery to the drains. In one catchment, drains contributed over 50% of the annual sediment budget. Spatial and temporal variations in the sources of sediment reaching one drain outlet were investigated in detail. A link between soil moisture deficit (SMD) and the frequency of high-intensity rainfall events was used to explain the appearance and persistence of a new sediment source in this drain after October 1998. It is concluded that field drains have the potential to be significant conduits of sediment and agrochemicals in a wide variety of environments in the UK. It is also suggested that this potential may increase if projected climate change leads to more intense rainfall events and increases in SMD across a greater area of the UK.

Chapman, A. S.; Foster, I. D. L.; Lees, J. A.; Hodgkinson, R. A.

2005-10-01

323

Speciation and Concentrations of Mercury in Certain Coastal Marine Sediments  

Microsoft Academic Search

Concentrations of total mercury (Hg), methyl Hg and Hg(II) were determined in coastal marine sediments collected from the Baltic, South China and the Bering Seas. Methyl Hg concentrations in sediments were between 0.01 and 2 ng g-1 on a dry weight basis, accounting for only <1% of the total Hg concentrations. The percentage of Hg(II) (i.e. available Hg) in total

K. Kannan; J. Falandysz

1998-01-01

324

Modeling sediment entrainment and transport processes limited by bed armoring  

Microsoft Academic Search

A sediment-transport model including a bed-armoring algorithm is used to ascertain the potential importance of bed-armoring processes. The parameters that control the bed-armoring effects on the suspension of granular sediments in the marine environment are examined using the numerical model and data from the Eel shelf. Results for the shelf indicate that bed armoring controls the total suspended-sediment load and

Christopher W. Reed; Alan W. Niedoroda; Donald J. P. Swift

1999-01-01

325

Bacterial community survey of sediments at Naracoorte Caves, Australia  

Microsoft Academic Search

Bacterial diversity in sediments at UNESCO World Heritage listed Naracoorte Caves was surveyed as part of an investigation carried out in a larger study on assessing microbial diversity in caves. Cave selection was based on tourist accessibility; Stick Tomato and Alexandra Cave (> 15000 annual visits) and Strawhaven Cave was used as control (no tourist access). Microbial analysis showed that

Eric M Adetutu; Krystal Thorpe; Esmaeil Shahsavari; Steven Bourne; Xiangsheng Cao; Ramin Mazaheri Nezhad Fard; Greg Kirby; Andrew S Ball

2012-01-01

326

Methods using passive sampling techniques in sediment for the estimation of pore water concentrations and available concentrations for hydrophobic contaminants  

Microsoft Academic Search

Hydrophobic contaminants entering the aqueous environment will generally sorb to particulate matter in the water phase and sediment due to their low water solubility. Sediment is often considered as a sink and\\/or buffer for hydrophobic contaminants. The risk of sediment contamination is related to what the sediment can release to the water phase, rather than the total concentration in the

Foppe Smedes

2007-01-01

327

Chronic toxicity of Great Lakes sediments to Daphnia magna: elutriate effects on survival, reproduction and population growth  

Microsoft Academic Search

Seventeen Great Lakes sediments ranging in degree of expected toxicity were evaluated using a 21 day sediment elutriate bioassay with Daphnia magna. Sediments differed in their effects on survival, age at first reproduction, the number of broods produced and the total number of young produced per adult. Sediments producing low survivorship (50–60%) also had negative effects on reproduction. However, both

Todd S. Bridges; Rachel Burres Wright; Brian R. Gray; Alfreda B. Gibson; Tom M. Dillon

1996-01-01

328

Deriving a spatially-explicit hillslope sediment delivery ratio model based on the travel time of water across a hillslope  

Microsoft Academic Search

To derive a sediment budget at the catchment scale, sediment transport models such as SedNet typically require an estimate to be made of the input of sediment to each stream link for each defined sub- catchment. This requires an estimate of both the erosion and delivery of sediment from every pixel within each sub-catchment. The total erosion within each pixel

A. E. Kinsey-Henderson; R. Bartley; A. Hawdon

329

Integrating the Chemical Fluxes of Transported Sediments in Large Rivers: AN Attempt on the Ganga  

NASA Astrophysics Data System (ADS)

Large rivers are the main conveyors of continental material to the oceans through sediment and dissolved fluxes. The redistribution of elements is fundamental in Earth surface processes and central in various biogeochemical cycles. The nature of the exported continental material is a function of the processes operating in the river’s catchment. From external forcings such as climate, tectonics or anthropogenic activity, having a strong control on erosion and weathering, to transport dynamics and sediment storage in flood plain, chemical elements are segregated from source to sink. Evaluating the composition of the exported sediments is thus essential in our understanding of large scale processes. This raises the problem of integrating the sediments chemical composition both spatially in a river section and temporally during the hydrogram. Efforts have been made to precisely determine de total flux of transported material of major world rivers but the determination of associated chemical solid fluxes is still limited. Also it is now recognized that surface sediments composition does not reflect in most cases the average sediment composition (Galy et al. 2007; Bouchez et al. in press). Nevertheless, global chemical budgets still rely on simple averaging of the available data counting mainly on surface sediment samples. Hydrodynamic sorting of minerals exerts a first order control on the chemistry of sediments in the water column, segregating elements according to the flow dynamics and the water depth. This has to be accounted for in order to derive accurate chemical fluxes. This work is an attempt to integrate the chemical flux of the sediments transported by the Ganga. The river was sampled at various stages of the monsoon at the same location in Bangladesh between 2004 and 2010 using a point sampler to collect sediments throughout the water column. Sediments were analyzed for major elements and grain-size. The systematic use of Acoustic Doppler Current Profilers (ADCP) surveys during sampling allows us to document the hydrodynamic conditions at the sampling location. Building upon a Rousean model we are able to predict the grain size of the vertical water column and extrapolate it through the river section. Then, using the strong correlation between grain size parameters and major element composition (Al, Si, Fe) we infer the chemical flux associated with the river section. Extrapolating these fluxes through the annual hydrologic cycle we attempt to constrain the chemical flux of the sediments exported by the Ganga. The chemical composition of this exported material is finally compared to the composition of the Himalayan crust. The significant difference between these two compositions is principally interpreted as the result of the sequestration of coarse silicic material in the flood plain. J. Bouchez et al. in press, Hydrological Processes V. Galy et al., 2007, Nature 450 : 407-411

France-Lanord, C.; Lupker, M.; Lavé, J.; Bouchez, J.; Galy, V.; Gaillardet, J.; Metivier, F.

2010-12-01

330

Microcystin Concentrations in the Nile River Sediments and Removal of Microcystin-LR by Sediments During Batch Experiments  

Microsoft Academic Search

During the present study, microcystin (MCYST) concentrations in the Nile River and irrigation canal sediments, Egypt, were\\u000a investigated during the period January–December 2001. Batch experiments were also conducted to confirm the adsorption of MCYSTs\\u000a on these sediments. The results of field study showed that MCYST concentrations in the sediments were correlated with total\\u000a count of cyanobacteria, particularly Microcystis aeruginosa, and

Zakaria A. Mohamed; Hassan M. El-Sharouny; Wafaa S. Ali

2007-01-01

331

Evaluation of the AnnAGNPS model for predicting runoff and sediment yield in a small Mediterranean agricultural watershed  

NASA Astrophysics Data System (ADS)

Four experimental watersheds with contrasting land uses located in Navarre (Spain), and maintained by the local government have been monitored and studied since 1996 (La Tejería and Latxaga) and 2001 (Oskotz principal and Oskotz woodland). As a result, a detailed description and a general characterization of the hydrological and erosion behaviour of these watersheds were published recently by the same authors of this current research. This information is of great utility for evaluation of modelling tools; however, we have been done few efforts until now in this research line. The Annualized Agricultural Non Point Source Pollution Model (AnnAGNPS) is a well known and widely used model developed by the USDA-ARS and the USDA- NRCS, to assess the hydrologic and water quality responses of watersheds. More precisely, it is a distributed parameter, physically based, continuous simulation, and daily time step model. The purpose of this study is then to evaluate the AnnAGNPS model capability to simulate runoff and sediment yield with data sets from one of our agricultural watershed: Latxaga. Latxaga watershed covers an area of 207 ha and is located in the central eastern part of Navarre. Its climate is humid Sub-Mediterranean, with an average annual precipitation of 835 mm, and an average annual temperature of 12.8 °C. Geologically, the area is underlined by clay marls and sandstones. Prevailing soils are alkaline with a fine texture top-layer. Regarding land use, 80-90% of the total area is cultivated with winter grain crops. The model was calibrated using two years (2003 and 2004) of continuous 10-min/daily data, whereas another whole year (2005) was used for model validation. The calibration process was carried out by modifying Curve Number (CN) values obtained by standard procedure. CN represents a key factor in obtaining accurate prediction of runoff and sediment yield; besides it is the most important input parameter to which the runoff is sensitive. The target variable was total annual runoff and its temporal evolution during each year. Model performance assessment after calibration was carried out by qualitative (by visual comparison of graphics) and quantitative approaches (using Nash and Sutcliffe's coefficient of efficiency E for monthly values, coefficient of determination R2 and coefficient of residual mass CRM). The initial values of CN, unique for each land use, were modified; in spite of achieving a satisfactory capability in simulating runoff/sediment yield, CN was anyway splitted up, adjusting the values to the main different stages of each crop. In that way, the model performance dramatically improved. Then, the predicted and measured annual average runoff after calibration were respectively 70.17 and 70.78 mm/ha/year, with R2= 0.78 and E = 0.77. However, annual sediment yields and peak flows were over predicted respectively by 42% and 26%. Sediment yield were over estimated especially during dry season and the beginning of wet season where (sometimes) some runoff was predicted even though none was in fact recorded. This suggests that during summer/autumn period the hydrologic component of the model was not able to satisfactorily reproduce the interaction between the drier antecedent conditions/high water holding capacity of soils before any event and the small total volume -though high intensity- of the rainfalls. Regarding model validation, a satisfactory estimation of runoff with E> 0.57 was also obtained. Finally, it can be stated that AnnAGNPS arises as a promising management tool for our agricultural watersheds.

Chahor, Youssef; Casalí, Javier; Goñi, Mikel; Giménez, Rafael; Campo, Miguel A.; Del Valle de Lersundi, Jokin

2010-05-01

332

Hydraulic potential in Lake Michigan bottom sediments  

USGS Publications Warehouse

The magnitude and direction of groundwater flux in the bottom sediments of Lake Michigan were deduced from measurements made during three shipboard cruises between 1973 and 1975. These factors affect the geochemical environment of the sediments and therefore the distribution of trace elements reported to be present. The near-shore, sandy-bottom and fine-grained, soft, deep-lake sediments were investigated; areas of hard till or bedrock were not included in the study. Thirty-three piezometers were placed in near-shore sands in waters 5-15 m deep. The piezometers were placed an average of 3 m into the bottom sediment. Water levels from the piezometers averaged 0.6 cm above the lake level, equivalent to an upward hydraulic gradient of about 0.002 cm/cm. Water samples taken from the piezometers have a distinctly different chemical composition from that of the lake water. The total dissolved mineral content and hardness of the groundwater are about twice those of the lake water. Twenty-two hydraulic gradient measurements were made in the fine-grained soft deep-lake sediments in waters 48-140 m deep by using a differential-pressure transducer dropped into the sediments. These measurements show an upward gradient averaging 0.2 cm/cm. No chemical data were obtained for the groundwater in the deep-lake sediments. The results of this study indicate that the groundwater flux is upward through the bottom sediments into Lake Michigan and that there is a chemical change in the water near the water-sediment contact. ?? 1979.

Cartwright, K.; Hunt, C. S.; Hughes, G. M.; Brower, R. D.

1979-01-01

333

Decadal sediment accumulation rates on the floodplain of the Strickland River, Papua New Guinea  

NASA Astrophysics Data System (ADS)

Rate of aggradation and infilling of accommodation space along lowland channels in response to post-glacial sea level rise should depend on sediment supply. The Strickland and Fly Rivers join at just 6 m above sea level, and the Strickland has historically carried about 7 times the sediment load and twice the river discharge as the Fly. Here we test the hypothesis that the lowland Strickland River floodplain should now have a lower sediment trap efficiency (due to more fully developed floodplains) than the middle Fly River, which currently losses about 40% of its load to the floodplain annually. We use mine-derived elevated Pb and Ag in floodplain core samples to determine the rates of sedimentation across the lower Strickland floodplain. Field sampling campaigns were conducted in 1997 and 2003, collecting shallow (less than 1 m) core samples at 5 relatively straight reaches up to 2 km from channel banks (in 1997 and 2003) and from 3 strongly curved sections, as well as from other sites of interest (2003). Various observations indicate that the concentration of particulate metals in overbank floods varies with stage, drought-flood cycles, and through the life of the mine. Sediment accumulation declines across the floodplain from the channel bank with an average rate of about 1.4 cm/yr over the first 1 km. Some sedimentation farther out did occur but is not well defined by our data. Overbank deposition is about 13% of the total load. Sedimentation rate per unit area is perhaps 10 times that measured on the Fly, but lateral migration on the Strickland is sufficiently high (average 5 m/yr) that overbank deposits are returned to the channel, significantly reducing potential net deposition to the floodplain. We conclude that the Strickland, which is nearly 10 times steeper than the Fly, and has much higher overbank deposition rates, nonetheless has less net deposition than the Fly because of the more vigorous lateral migration (which apparently results from the higher load). Hence, our field observations support our initial hypothesis, though the primary reason for this may be due to active lateral migration rather than low overbank deposition.

Swanson, K. M.; Watson, E.; Aalto, R.; Lauer, J. W.; Bera, M. T.; Marshall, A.; Taylor, M.; Apte, S. C.; Dietrich, W. E.

2006-12-01

334

Sediment transfer dynamics in the Illgraben  

NASA Astrophysics Data System (ADS)

Quantification of the volumes of sediment removed by rock-slope failure and debris flows and identification of their coupling and controls are pertinent to understanding mountain basin sediment yield and landscape evolution. We analyzed photogrammetrically-derived datasets of hillslope and channel erosion and deposition along with hydroclimatic variables from the Illgraben, an active debris flow catchment in the Swiss Alps, spanning 1963 - 2010. Two events in the recent history of the catchment make it particularly interesting and challenging to study: a large rock avalanche in 1961, which filled the channel with sediment, and the construction of check dams along the channel in the late 1960s and 1970s. We aimed to (1) identify the nature of hillslope-channel coupling, (2) identify the dominant controls of hillslope sediment production, channel sediment transfer and total sediment yield, (3) observe the response of the channel system to the 1961 rock avalanche and check dam construction, and (4) develop a conceptual model with which to investigate sediment transfer dynamics in various scenarios, including the absence of check dams along the channel. The study captures a multi-decadal period of channel erosion in response to the 1961 rock avalanche, punctuated by shorter cut-and-fill cycles that occur in response to changes in hillslope sediment supply and changes in transport capacity. Hillslopes eroded rapidly at an average rate of 0.34 myr¯ 1, feeding the channel head with sediment. A near doubling of hillslope erosion in the 1980s coincided with a significant increase of air temperature and reduction in snow cover duration and depth, whilst precipitation variables did not change significantly. We find that the main influence of check-dam construction on channel sediment transfer was an initial reduction in sediment transport and a drop in debris flow activity between 1963 and 1986. After 1986 sediment storages in the channel were filled and debris flow activity resumed. During this time hillslope erosion exceeded channel erosion by 0.14myr¯ 1 indicating that hillslopes eroded independently of channel incision. Channel sediment transfer was transport-limited at the scale of the study as suggested by the aggradation of the channel in periods of very high hillslope flux and its apparent relation to variables connected to runoff generation such as precipitation and snowmelt. We have developed a conceptual model of sediment transfer based on our data set with which to investigate sediment transfer dynamics in a probabilistic sense. A stochastic sediment input from the hillslopes is generated from our magnitude-frequency model of landslides. Sediment is fed into a hillslope storage component, where a fraction is redeposited in long-term storage. Sediment in short-term storage is subsequently fed into the channel system and is only removed given a transport event (rainfall or snowmelt) of sufficient magnitude and sufficient available sediment. Transport events are generated stochastically using a weather generator. We calibrate the model with available data. Despite its simplicity the model reproduces the storage and discharge behavior of the channel system observed over the study period and enables us to test the sensitivity of the system to different parameters and system structures.

Bennett, G. L.; Molnar, P.; McArdell, B. W.; Schlunegger, F.; Burlando, P.

2012-04-01

335

Interactions between sediment resuspension and sediment quality decrease the TN : TP ratio in a shallow lake  

Microsoft Academic Search

The relative contributions of sediment resuspension and external nutrient loading to seasonal fluctuations of the total nitrogen to total phosphorus (TN : TP) ratio in the water column of the shallow Kirkkojarvi basin were studied. In May, the TN : TP mass ratio was above 30, but it decreased to below 10 in July-August. In October, the ratio increased again.

Juha Niemisto; Heidi Holmroos; Zeynep Pekcan-Hekim; Jukka Horppila

2008-01-01

336

Characteristics of suspended sediment in the San Juan River near Bluff, Utah  

USGS Publications Warehouse

Fluvial-sediment data were collected for the San Juan River near Bluff beginning in 1914 and terminating in 1980. A double-mass curve showed a change in relationship between annual suspended-sediment discharge and annual stream discharge between the water years 1941-44 and 73. Possible causes for these changes in laboratory procedures, and unusually large runoff that occurred in 1941 and 1972. An unknown or unidentified factor may also be involved. The actual reason for this change in relationship may never be fully understood. Navajo Dam apparently has had no significant effect on fluvial sediment at the sampling site. Mean annual suspended sediment discharge in the San Juan River near Bluff was about 25,410,000 tons ranging from 3,234,000 tons in 1978 to 112,400,000 tons in 1941. The use of annual stream discharge to predict annual suspended-sediment discharge at the site will produce poor results because of size and diversity of the basin and the quality of records available. A positive correlation exists between sand concentration and stream discharge at this site, however, considerable variability is evident. This relationship does not exist when stream discharge exceeds 6,000 cubic feet per second. It is recommended that if collection of suspended-sediment records be resumed in this reach of the river an alternative sampling site should be selected and the use of pumping samplers considered because of the remoteness of the area. (USGS)

Thompson, K. R.; Mundorff, J. C.

1982-01-01

337

Total and subtotal abdominal hysterectomy.  

PubMed

Hysterectomy is one of the most frequently performed operations in the world, accounting for 500,000-600,000 procedures annually in the USA; the abdominal route for hysterectomy is the preferred route in 60-80% of these operations. Although the number of total abdominal hysterectomies performed annually has decreased, the number of subtotal abdominal hysterectomies increased by >400%. The major indications for abdominal hysterectomy include abnormal uterine bleeding, myomata uteri, adenomyosis, endometriosis, neoplasia, and chronic salpingitis. The basis for selection for subtotal versus total hysterectomy has little in the way of factual data to support it and may actually present some significant disadvantages, such as continued menstruation and cervical prolapse. The detailed technique for performing intrafascial abdominal hysterectomy relies heavily on precise knowledge of pelvic anatomy and compulsive detail to tissue handling. The consistent and correct usage of prophylactic antimicrobials, measures to prevent thromboemboli, and procedures to avoid urinary retention are key to the overall success of the surgery. PMID:15985251

Baggish, Michael S

2005-02-05

338

SUSPENDED SEDIMENT: DATA NEEDS, UNCERTAINTY, AND EMERGING TECHNOLOGIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Changes in the amount of sediment carried by a stream or river have been identified as the single largest reason for their being listed as impaired on the 1996 National Water Quality Inventory (Section 305(b) Report to Congress). Accurate assessments of total sediment loads can be used to identify ...

339

MERCURY IN SEDIMENT AND FISH FROM NORTH MISSISSIPPI LAKES.  

EPA Science Inventory

Sediments and/or fish were collected from Sardis, Enid and Grenada Lakes, which are located in three different watersheds in North Mississippi, in order to assess mercury contamination. The mean total mercury concentration in sediments from Enid Lake in 1997 was 0.154 mg Hg/kg, w...

340

Macroinvertebrates in the bed sediment of the Yellow River  

Microsoft Academic Search

Extensive agricultural, industrial and urban development in the Yellow River, China, have modified the sediment-water balance, flow and inundation regimes, longitudinal connectivity, integrity of riparian vegetation, and water quality. Macroinvertebrate assemblages in the bed sediment of main channel and major reservoirs of the Yellow River are described in detail for the first time. A total of 74 taxa comprising 17

Weihua ZHAO; Haijun WANG; Hongzhu WANG; Paul G. CLOSE

2011-01-01

341

A site-specific evaluation of mercury toxicity in sediment.  

PubMed

A site-specific evaluation of mercury toxicity was conducted for sediments of the Calcasieu River estuary (Louisiana, USA). Ten-day whole-sediment toxicity tests assessed survival and growth (dry weight) of the amphipods Hyalella azteca and Leptocheirus plumulosus under estuarine conditions (10 ppt salinity). A total of 32 sediment samples were tested for toxicity, including 14 undiluted site sediment samples and 6 sediment dilution series. All sediment samples were analyzed for total mercury and numerous other chemical parameters, including acid volatile sulfide (AVS) and simultaneously extracted metals (SEM). No toxicity attributable to mercury was observed, indicating that a site-specific threshold for total mercury toxicity to amphipods exceeds 4.1 mg/kg dry weight. Site-specific factors that may limit mercury bioavailability and toxicity include relatively high sulfide levels. Additionally, the chemical extractability of mercury in site sediments is low, as indicated by SEM mercury analyses for three sediment samples containing a range of total mercury concentrations.http://link. springer-ny.com/link/service/journals/00244/bibs/37n4p488.++ +html

Sferra, J C; Fuchsman, P C; Wenning, R J; Barber, T R

1999-11-01

342

Progress towards Acoustic Suspended Sediment Transport Monitoring: Fraser River, BC  

NASA Astrophysics Data System (ADS)

Our ability to predict the timing and quantity of suspended sediment transport is limited because fine sand, silt and clay delivery are supply limited, requiring empirical modeling approaches of limited temporal stability. A solution is the development of continuous monitoring techniques capable of tracking sediment concentrations and grain-size. Here we examine sediment delivery from upstream sources to the lower Fraser River. The sediment budget of the lower Fraser River provides a long-term perspective of the net changes in the channels and in sediment delivery to Fraser Delta. The budget is based on historical sediment rating curves developed from data collected from 1965-1986 by the Water Survey of Canada. We explore the possibility of re-establishing the sediment-monitoring program using hydro-acoustics by evaluating the use of a 300 kHz side-looking acoustic Doppler current profiler (aDcp), mounted just downstream of the sand-gravel transition at Mission, for continuous measurement of suspended sediment transport. Complementary field observations include conventional bottle sampling with a P-63 sampler, vertical profiles with a downward-looking 600 kHz aDcp, and 1200 kHz aDcp discharge measurements. We have successfully completed calibration of the downward-looking aDcp with the P-63 samples; the side-looking aDcp signals remain under investigation. A comparison of several methods for obtaining total sediment flux indicates that suspended sediment concentration (SSC) closely follows discharge through the freshet and peaks in total SSC and sand SSC coincide with peak measurements of discharge. Low flows are dominated by fine sediment and grain size increases with higher flows. This research assesses several techniques for obtaining sediment flux and contributes to the understanding of sediment delivery to sand-bedded portions of the river.

Attard, M. E.; Venditti, J. G.; Church, M. A.; Kostaschuk, R. A.

2011-12-01

343

Silver toxicity to Chironomus tentans in two freshwater sediments  

SciTech Connect

Sediment collected from two freshwater lakes, West Bearskin Lake (Cook, MN, USA) and Bond Lake (Douglas, WI, USA), was characterized for grain size, total organic carbon, (TOC), acid-volatile sulfides (AVS), simultaneously extracted metals (SEM), and iron (Fe). Both sediments had low levels of TOC. West Bearskin Lake sediment contained more small particles than Bond Lake, which was 95% sand. West Bearskin Lake also had higher SEM and had an Fe content that was approximately 30-fold greater than that of Bond Lake. These sediments were amended with AgNO{sub 3} in a series of concentrations, some of which were intended to exceed the total silver (Ag)-binding capacity of the sediments, allowing for the appearance of dissolved Ag in pore water (PW). Sediment toxicity tests were then designed such that the AgNO{sub 3} amendment levels would result in PW concentrations that bracketed the 10-d concentration causing 50% lethality for dissolved Ag of 0.057 mg/L, as determined in a toxicity test in water alone. The 10-d LC50 values for Chironomus tentans, based upon nominal additions of Ag to the sediments, were 2.75 and 1.17 g Ag per kilogram dry sediment for West Bearskin and Bond Lake sediments, respectively. An LC50 value based upon dissolved Ag in the PW was determined only for Bond Lake sediment and was approximately 275 times greater than the water-only LC50 value. This indicated that a high proportion of the dissolved fraction was not readily bioavailable to cause lethality. A reduction in PW pH and the displacement of other metals from sediment into PW with Ag additions to the sediment likely contributed to the observed mortalities and weight losses, particularly at the higher exposure levels. The concentrations of Ag in these sediments that resulted in biological effects are considerably higher than levels reported in the environment.

Call, D.J.; Polkinghorne, C.N.; Markee, T.P.; Brooke, L.T.; Geiger, D.L. [Univ. of Wisconsin, Superior, WI (United States). Lake Superior Research Inst.; Gorsuch, J.W.; Robillard, K.A. [Eastman Kodak Co., Rochester, NY (United States)

1999-01-01

344

Coal industry annual 1997  

SciTech Connect

Coal Industry Annual 1997 provides comprehensive information about US coal production, number of mines, prices, productivity, employment, productive capacity, and recoverable reserves. US Coal production for 1997 and previous years is based on the annual survey EIA-7A, Coal Production Report. This report presents data on coal consumption, coal distribution, coal stocks, coal prices, and coal quality for Congress, Federal and State agencies, the coal industry, and the general public. Appendix A contains a compilation of coal statistics for the major coal-producing States. This report includes a national total coal consumption for nonutility power producers that are not in the manufacturing, agriculture, mining, construction, or commercial sectors. 14 figs., 145 tabs.

NONE

1998-12-01

345

Status and trends in suspended-sediment discharges, soil erosion, and conservation tillage in the Maumee River basin--Ohio, Michigan, and Indiana  

USGS Publications Warehouse

The relation of suspended-sediment discharges to conservation-tillage practices and soil loss were analyzed for the Maumee River Basin in Ohio, Michigan, and Indiana as part of the U.S. Geological Survey?s National Water-Quality Assessment Program. Cropland in the basin is the largest contributor to soil erosion and suspended-sediment discharge to the Maumee River and the river is the largest source of suspended sediments to Lake Erie. Retrospective and recently-collected data from 1970-98 were used to demonstrate that increases in conservation tillage and decreases in soil loss can be related to decreases in suspended-sediment discharge from streams. Average annual water and suspended-sediment budgets computed for the Maumee River Basin and its principal tributaries indicate that soil drainage and runoff potential, stream slope, and agricultural land use are the major human and natural factors related to suspended-sediment discharge. The Tiffin and St. Joseph Rivers drain areas of moderately to somewhat poorly drained soils with moderate runoff potential. Expressed as a percentage of the total for the Maumee River Basin, the St. Joseph and Tiffin Rivers represent 29.0 percent of the basin area, 30.7 percent of the average-annual streamflow, and 9.31 percent of the average annual suspended-sediment discharge. The Auglaize and St. Marys Rivers drain areas of poorly to very poorly drained soils with high runoff potential. Expressed as a percentage of the total for the Maumee River Basin, the Auglaize and St. Marys Rivers represent 48.7 percent of the total basin area, 53.5 percent of the average annual streamflow, and 46.5 percent of the average annual suspended-sediment discharge. Areas of poorly drained soils with high runoff potential appear to be the major source areas of suspended sediment discharge in the Maumee River Basin. Although conservation tillage differed in the degree of use throughout the basin, on aver-age, it was used on 55.4 percent of all crop fields in the Maumee River Basin from 1993-98. Conservation tillage was used at relatively higher rates in areas draining to the lower main stem from Defiance to Waterville, Ohio and at relatively lower rates in the St. Marys and Auglaize River Basins, and in areas draining to the main stem between New Haven, Ind. and Defiance, Ohio. The areas that were identified as the most important sediment-source areas in the basin were characterized by some of the lowest rates of conservation tillage. The increased use of conservation tillage was found to correspond to decreases in suspended-sediment discharge over time at two locations in the Maumee River Basin. A 49.8 percent decrease in suspended-sediment discharge was detected when data from 1970-74 were compared to data from 1996-98 for the Auglaize River near Ft. Jennings, Ohio. A decrease in suspended-sediment discharge of 11.2 percent was detected from 1970?98 for the Maumee River at Waterville, Ohio. No trends in streamflow at either site were detected over the period 1970-98. The lower rate of decline in suspended-sediment discharge for the Maumee River at Waterville, Ohio compared to the Auglaize River near Ft. Jennings, may be due to resuspension and export of stored sediments from drainage ditches, stream channels, and flood plains in the large drainage basin upstream from Waterville. Similar findings by other investigators about the capacity of drainage networks to store sediment are supported by this investigation. These findings go undetected when soil loss estimates are used alone to evaluate the effectiveness of conservation tillage. Water-quality data in combination with soil-loss estimates were needed to draw these conclusions. These findings provide information to farmers and soil conservation agents about the ability of conservation tillage to reduce soil erosion and suspended-sediment discharge from the Maumee River Basin.

Myers, Donna N.; Metzker, Kevin D.; Davis, Steven

2000-01-01

346

Global carbon cycles: A coupled atmosphere-ocean-sediment model  

SciTech Connect

A simple one-dimensional advective-diffusive ocean model with a polar outcrop is developed and calibrated to fit modern ocean temperature, phosphorus, oxygen, total carbon, and total alkalinity data. The ocean model includes an atmospheric box which predicts atmospheric P[sub CO2] and oxygen concentrations. In addition, a sediment model is designed to reproduce modern sediment profiles of solid organic carbon and calcite, and pore water oxygen, sulfate, carbonate bicarbonate and carbon dioxide. The organic matter sediment model is used to investigate the interplay of sedimentation rate, bioturbation and microbial kinetics on the total rates of organic carbon and phosphorus regeneration and accumulation in marine sediments. This is done for sediments ranging from coastal to deep ocean. The model is sensitive to the organic carbon flux, sedimentation rate, bottom water oxygen concentration, degradation kinetics and bioturbation rate. The type of diagenetic environment and the extent of remineralization is very dependent on these variables which are currently poorly constrained. The carbonate model uses organic carbon, oxygen and sulfate profiles from the organic sediment as input in addition to the total carbon and alkalinity of the overlying water. It predicts the carbonate, bicarbonate and carbon dioxide pore water concentrations and the sedimentary carbonate fraction. The lysocline and carbonate compensation depth are sensitive to the calcite dissolution rate, the organic to inorganic carbon ratio and organic matter degradation. The sediment and ocean models are combined to form an atmosphere-ocean-sediment model which is used to test the hypothesis that decreased polar surface nutrients and carbon is the cause of the 80 ppm reduction in atmospheric P[sub CO2] observed during the last ice age. The coupled model suggests that sediments play an important role in the global carbon budget.

Tromp, T.K.

1992-01-01

347

Sediment Discharge in Rock Creek and the Effect of Sedimentation Rate on the Proposed Rock Creek Reservoir, Northwestern Colorado.  

National Technical Information Service (NTIS)

Sediment data collected from 1976 to 1985 and stream-discharge data collected from 1952 to 1980 at gaging station 09060500, Rock Creek near Toponas, Colorado, were used to determine total-sediment discharge into the proposed Rock Creek Reservoir. Suspende...

D. L. Butler

1987-01-01

348

Concentrations of DDTs and dieldrin in Long Island Sound sediment.  

PubMed

The concentrations of three frequently detected organochlorine pesticides (OCPs) and one degradation product, p,p'-DDT, p,p'-DDD, dieldrin, and p,p'-DDE were determined in recently collected (2005-2006) and archived (1986-1989) surficial sediments and sediment cores from Long Island Sound (LIS). The concentration of dieldrin ranged from 0.05 to 5.27 ng g(-1) dry weight in the surficial sediments, and from 0.05 to 11.7 ng g(-1) dry weight in the sediment cores. Total DDXs (the sum of p,p'-DDE, p,p'-DDD and p,p'-DDT) concentrations ranged from 1.31 to 33.2 ng g(-1) in surficial sediments and 1.11 to 66.4 ng g(-1) in sediment cores. The results indicate that the three OCPs and DDE were still widely present in LIS surficial sediments two decades after the use of these pesticides in the United States was banned. In addition, the surficial concentrations did not decrease significantly when compared to the concentrations in archived samples collected two decades ago. Sediments in the western part of LIS were more contaminated (with concentrations in some western sites being still above probable effect levels) than those in the eastern part, probably as a result of the net westward sediment transport in LIS. The three OCPs and DDE were detected at all depths (down to ~50 cm) in the sediment cores, and concentration profiles indicated a depositional sedimentary environment with significant sediment mixing. Such mixing may redistribute OCPs deposited earlier (deeper in sediment bed) to the sediment surface and lead to enhanced persistence of OCP concentrations in surficial sediments. PMID:22281775

Yang, Lijia; Li, Xiqing; Zhang, Pengfei; Melcer, Michael E; Wu, Youxian; Jans, Urs

2012-01-26

349

Sediment Sources and Storage in the Chesapeake Bay Watershed  

NASA Astrophysics Data System (ADS)

Physically and chemically, sediment is a pollutant of concern in many waterbodies. In the Chesapeake Bay, sediment is having an adverse effect on the living resources and habitat of the Chesapeake Bay and its watershed. Identifying significant sources of watershed sediment is important in reducing sediment loads. In the Chesapeake Bay, several approaches were used to understand the sources, transport, and storage of watershed-derived sediment. From 1985 through 2001, the U.S. Geological Survey collected suspended sediment at 35 stations draining portions of the 103,000 km2 Chesapeake Bay. Of the 35 sites, 4 of the 6 highest sediment yields were in the Conestoga River Basin, Pennsylvania, which drains to the Susquehanna River. In the Susquehanna River Basin (43,600 km2), erosion rates were determined using atmospheric 10Be at 92 river outlets and confirmed that the highest rates of erosion were in the Conestoga River Basin. In three small watersheds draining to the Chesapeake Bay -- the Pocomoke River (157 km2), Little Conestoga Creek (68.1 km2), and Mattawoman Creek (92.8 km2) -- sediment sources were identified using a sediment-source identification approach. In this approach, the sources of fine-grained suspended sediment in transport can be established by comparing physical and chemical properties of the suspended sediment to potential sources. In this study, suspended sediment (< 0.062 mm) collected during storm runoff was compared to upland sediment sources (cropland, construction sites, and forest) and channel corridor sources (channel banks and bed) using radionuclides (210Pb, 137Cs), stable isotopes (13C, 15N), and total C, N, and P. Preliminary results are available for two of the three watersheds. In the Pocomoke River watershed, which drains the Coastal Plain physiographic province, ditch beds which were dug to drain cropland were a significant source of sediment. In the Little Conestoga Creek watershed, which drains the Piedmont physiographic province, river banks and cropland were significant sources.

Gellis, A. C.; Landwehr, J. M.; Pavich, M.; Hupp, C. R.; Ritchie, J. C.

2006-05-01

350

35th Annual Official Education Construction Report  

ERIC Educational Resources Information Center

Spending on construction by the nation's education institutions increased in 2008, reversing four years of declines in total annual expenditures, according to "American School & University"'s 35th annual Official Education Construction Report. One of the reasons for the increase in spending was the fact that the majority of the construction…

Agron, Joe

2009-01-01

351

Sedimentation rates and erosion processes in the lagoon of Venice.  

PubMed

Since the early 1990s in the lagoon of Venice, especially in the central basin, the surface sediment underwent high re-suspension and sedimentation changes and water turbidity increased both because of the disappearance of the macroalgal coverage and the harvesting of the Manila clam Tapes philippinarum Adams and Reeve, which had rapidly colonised the bottom free of macrophytes. Clams are harvested with hydraulic and mechanical dredges which remove and re-suspend surface sediments causing the transport and loss of the finest materials. Sediment transport and re-deposition in the lagoon have been monitored with sediment traps placed onto the bottoms near the Malamocco mouth (st. A), the Lido watershed (st. B) and the mainland (sts. C and D). From 1989-1993 to 1998-1999 sedimentation rates increased significantly at st. A (from 41 to 228 kg DW m(-2) year(-1)), st. B (from 65 to 760 kg DW m(-2) year(-1)) and st. C (from 140 to 721 kg DW m(-2) year(-1)), while at st. D sedimentation rates increased only by ca. 20%. In parallel sediment grain-size changed with a loss of the finest fraction especially near the mainland. The erosion or sedimentation status, acquired by utilizing sedimentation devices placed onto the bottoms, showed that sts. B, C, D were affected by sediment losses, while st. A, populated by seagrasses and characterised by seasonal variations which depend on the shoot development, did not show any significant bathymetric change on an annual basis. The highest sediment erosion was recorded at st. D (ca. 3.6 cm year(-1)) whereas a loss of ca. 1.5 and 0.5 cm year(-1) was found at sts. C and B, respectively, which accounted for a mean loss in the central lagoon of ca. 1.2 million tonnes year(-1). Those data agree with the previous indirect estimation of sediment loss which was based on the number of fishing boats operating in the lagoon on an annual basis. PMID:16083960

Sfriso, Adriano; Adriano, Sfriso; Facca, Chiara; Chiara, Facca; Marcomini, Antonio; Antonio, Marcomini

2005-09-01

352

Your Annual Health Care Visit  

MedlinePLUS

Your Annual Health Care Visit Home About ACOG ACOG Departments & Activities Annual Women's Health Care Your Annual Health Care Visit Page Navigation ? ... about your annual health care exam Your Annual Health Care Visit Having an annual health care visit is ...

353

Bacterial magnetite produced in water column dominates lake sediment mineral magnetism: Lake Ely, USA  

NASA Astrophysics Data System (ADS)

Environmental magnetic studies of annually laminated sediments from Lake Ely, northeastern Pennsylvania, USA indicate that bacterial magnetite is the dominant magnetic mineral in the lake sediment. In previous studies of Lake Ely sediment, the dark, organic-rich layers in the annual laminae were interpreted to have high-intensity saturation isothermal remanent magnetizations (SIRMs) while the light-coloured, silt-rich layers have low-intensity SIRMs. To test the hypothesis that the magnetic grains in the sediments were an authigenic product of magnetotactic bacteria rather than detrital magnetic grains eroded from the watershed, we analysed samples from the water column, the lake sediment, and a sediment trap installed near the lake bottom. Direct microscopic observation of the water column samples showed the presence of magnetotactic bacteria in and below the oxic-anoxic transition zone (OATZ). To characterize the magnetic minerals, rock magnetic parameters were measured for material from the water column, the sediment trap and the dark- and light-coloured lake sediments. Low-temperature magnetic measurements tested for the presence of magnetosomes in separated dark- and light-coloured layer samples. Numeric unmixing of the low-temperature results showed that biogenic magnetites were present in the lake sediment and contributed more significantly to the SIRM in the dark, organic-rich layers than in the light-coloured, inorganic silt-rich layers. Observations under the transmission electron microscope (TEM) of magnetic extracts also show the abundance of magnetosomes in the lake sediment. The presence of live magnetotactic bacteria in the water column and the predominance of bacterial magnetites in filtered particulate matter, sediment traps and recent lake sediment all suggest that bacterial magnetites are the main magnetic minerals in Lake Ely sediment. This finding suggests that changes in environmental factors that control the productivity of magnetic bacteria in the lake likely contribute to the variability of magnetic mineral concentrations observed in the lake sediments.

Kim, BangYeon; Kodama, Kenneth P.; Moeller, Robert E.

2005-10-01

354

Evaluation of a hydrograph-shifting method for estimating suspended-sediment loads in Illinois streams  

SciTech Connect

A hydrograph-shifting method for estimating monthly and annual suspended-sediment loads was applied to suspended-sediment records for 12 streams in Illinois. Transport equations for each station were obtained from 2 years of suspended-sediment discharge and streamflow data. Synthetic sediment-discharge hydrographs were generated by using the transport equations and daily records of streamflow. These hydrographs were shifted to measured values of daily sediment discharge (control points) selected to represent weekly, biweekly, and monthly sampling frequencies. Estimates of monthly suspended-sediment load ranged from 16 to 326% of measured values. Estimates of annual suspended-sediment loads ranged from 41 to 136% of measured values, which indicates that the method provides a reasonable means of estimating annual loads for most sites. An experiment designed to measure the subjectivity of the method showed it to be more dependent on the particular days selected as control points than on the person applying the method. An evaluation of the effect of the length of record used to develop transport equations on sediment load estimates was not conclusive. Although standard errors of estimate showed no improvement, the comparison of estimated loads with measured loads showed slight improvement when an additional 1 or 2 years of data were added to the first year of data used to develop transport equations. 5 refs., 14 figs., 5 tabs.

Frost, L.R. Jr.; Mansue, L.J.

1984-01-01

355

Transient water and sediment storage of the decaying landslide dams induced by the 2008 Wenchuan earthquake, China  

NASA Astrophysics Data System (ADS)

Earthquake-triggered landslide dams are potentially dangerous disrupters of water and sediment flux in mountain rivers, and capable of releasing catastrophic outburst flows to downstream areas. We analyze an inventory of 828 landslide dams in the Longmen Shan mountains, China, triggered by the Mw 7.9 2008 Wenchuan earthquake. This database is unique in that it is the largest of its kind attributable to a single regional-scale triggering event: 501 of the spatially clustered landslides fully blocked rivers, while the remainder only partially obstructed or diverted channels in steep watersheds of the hanging wall of the Yingxiu-Beichuan Fault Zone. The size distributions of the earthquake-triggered landslides, landslide dams, and associated lakes (a) can be modeled by an inverse gamma distribution; (b) show that moderate-size slope failures caused the majority of blockages; and (c) allow a detailed assessment of seismically induced river-blockage effects on regional water and sediment storage. Monte Carlo simulations based on volumetric scaling relationships for soil and bedrock failures respectively indicate that 14% (18%) of the estimated total coseismic landslide volume of 6.4 (14.6) × 109 m3 was contained in landslide dams, representing only 1.4% of the > 60,000 slope failures attributed to the earthquake. These dams have created storage capacity of ~ 0.6 × 109 m3 for incoming water and sediment. About 25% of the dams containing 2% of the total river-blocking debris volume failed one week after the earthquake; these figures had risen to 60% (~ 20%), and > 90% (> 90%) within one month, and one year, respectively, thus also emptying ~ 92% of the total potential water and sediment storage behind these dams within one year following the earthquake. Currently only ~ 0.08 × 109 m3 remain available as natural reservoirs for storing water and sediment, while ~ 0.19 × 109 m3, i.e. about a third of the total river-blocking debris volume, has been eroded by rivers. Dam volume and upstream catchment area control to first order the longevity of the barriers, and bivariate domain plots are consistent with the observation that most earthquake-triggered landslide dams were ephemeral. We conclude that the river-blocking portion of coseismic slope failures disproportionately modulates the post-seismic sediment flux in the Longmen Shan on annual to decadal timescales.

Fan, Xuanmei; van Westen, Cees J.; Korup, Oliver; Gorum, Tolga; Xu, Qiang; Dai, Fuchu; Huang, Runqiu; Wang, Gonghui

2012-10-01

356

Investigating reservoir sediment and watershed erosion using a geographical information system  

NASA Astrophysics Data System (ADS)

Most economic developments may have been at the expense of soil conservation. Soil erosion results in impacts on reservoir sediment, crop yield, and water quality. This study introduces the procedure of using a geographical information system for investigating reservoir sediments and soil erosion of the corresponding watershed. First, the bathymetric surface of a reservoir is surveyed using two real-time kinematic global position systems and a sonar-based depth gauge. Using the on-board computer, receivers, and sonar, bathymetric readings are recorded three times a second to establish actual coordinates and depth measurements. Data are then converted using a digital terrain model to obtain the current image bathymetric surface. The image of original bathymetric surfaces when constructed can be obtained by digitizing the existing map. The subtraction of these two images is used to estimate the amount of sediment deposits. Next, parameters of rainfall-runoff erosivity factor, soil erodibility factor, slope length factor, slope steepness factor, cover-management factor, and support practice factor are evaluated for each grid of the corresponding watershed. The average annual soil loss from each grid is estimated by the revised universal soil loss equation to obtain the total amount of the soil loss for the watershed. Using the example of Charles Mill Lake, Ohio, USA, the estimated average amount of sediment deposits in the lake was about 2·44 × 104 m3 year-1. On the other hand, the estimated soil erosion from the corresponding watershed was about 4·22 × 108 kg year-1 or 1·56 × 105 m3 year-1. Hence, it can be concluded that about 15·6% of the soils eroded from the watershed have been deposited in the lake.

Chang, Tiao J.; Bayes, Travis D.; McKeever, Scott

2003-04-01

357

Establishment of total cavopulmonary connection without use of cardiopulmonary bypass 1 Presented at the 11th Annual Meeting of the European Association for Cardiothoracic Surgery, Copenhagen, Denmark, September 28 – October 1, 1997. 1  

Microsoft Academic Search

Objective: To minimize deleterious postoperative influences of cardiopulmonary bypass on the pulmonary circulation immediately after the Fontan type procedure, total cavopulmonary connection was achieved without use of cardiopulmonary bypass. Methods: Since April 1996, 15 patients including five patients with visceral heterotaxy, in whom no intracardiac procedure was needed, have undergone this operative maneuver. Age at operation ranged from 1.2 to

Hideki Uemura; Toshikatsu Yagihara; Katsushi Yamashita; Toru Ishizaka; Ko Yoshizumi; Youichi Kawahira

1998-01-01

358

SEDIMENT IMPACT ASSESSMENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Stream Design Guide provides guidance for multidisciplinary teams who are planning and designing projects that are intended to control floods or sediment sources, hasten drainage, stabilize banks, improve fish habitat, or restore ecological functions and processes. Sedimentation analysis is a ke...

359

Traceability of sediment analysis  

Microsoft Academic Search

Chemical analysis of sediments provides an efficient tool for water-quality management. A basic sequence of measurements comprises three steps: sampling and sample preparation; grain size as a characteristic sediment feature; and, analytical procedures based on standardized extraction schemes and reference materials. These can be considered as an unbroken chain of comparisons. Further steps are split with regard to specific purposes:

U. Forstner

2004-01-01

360

New strategies for upscaling high-resolution flow and overbank sedimentation models to quantify floodplain sediment storage at the catchment scale  

NASA Astrophysics Data System (ADS)

Quantitative models of catchment scale floodplain sediment storage must balance competing demands. For example, such approaches must incorporate a physically-based representation of controls on overbank sedimentation rates at the reach scale, but should also be computationally efficient so that catchment scale analysis remains a realistic goal. This paper reports the development of a novel nested modelling strategy that combines a high-resolution hydraulic model based on the shallow water form of the Navier Stokes equations, with a reduced complexity overbank sedimentation model and coarse-resolution catchment sediment budget model. The approach is implemented within a Monte-Carlo framework to allow an assessment of uncertainty in the parameterisation of overbank sedimentation processes, and to derive uncertainty-bounded estimates of floodplain sedimentation rates over a range of spatial scales. This strategy is applied to a 26 km reach of the River Culm, Devon, UK. The relative performance of a wide range of model structures is evaluated by comparing model predictions with estimates of actual mean annual sedimentation rates derived by analysis of the caesium-137 content of floodplain sediment cores at 20 locations within each of eight study sites distributed throughout the catchment. The results of the current model application demonstrate the potential of the nested modelling strategy as a means of upscaling physically-based flow and sediment transport codes. Furthermore, the novel reduced-complexity overbank sedimentation model presented here is shown to provide a means of simulating complex patterns of suspended sediment transport and deposition, while reducing computing costs by 2 3 orders of magnitude compared with conventional high-resolution advection diffusion codes. Uncertainty-bounded estimates of floodplain sediment storage for the River Culm confirm that floodplain sedimentation represents a primary component of the fine sediment budget of lowland catchments. Consequently, the modelling strategies developed here may also be of considerable value in attempts to quantify the fate of sediment-associated nutrients and contaminants at the basin scale.

Nicholas, A. P.; Walling, D. E.; Sweet, R. J.; Fang, X.

2006-10-01

361

Quantifying spatial patterns and timescales of fine sediment redistribution in river basins: application of a sediment budget model with fallout radionuclide tracers  

NASA Astrophysics Data System (ADS)

Improved understanding of fine sediment and associated contaminant redistribution within river basins requires information on the sources and rates of sediment supply alongside the timescales of downstream sediment transfer. Sediment budgets are an effective tool for examining these patterns. While small, intensively monitored research catchments may provide such information, the examination of larger scale patterns of sediment transfer often requires the use of modelling-based approaches. Furthermore, knowledge of timescales of fine sediment transfer in river basins is limited. Few studies link sediment budgets with explicit information on the residence or travel times of fine sediment. This information is essential for understanding contemporary patterns of river basin sediment redistribution, and has implications for predicting possible recovery times of rivers affected by contaminated sediment from historic or recent pollution. Against this background, we aim to quantify the spatial patterns and timescales of suspended sediment transfer through a river basin (917 km2) situated in south-west England. We apply a spatially-distributed sediment budget model (SedNet) in conjunction with high-resolution spatial data and long-term rainfall and river flow measurements. Model outputs provide an indication of mean annual patterns of sediment redistribution and yields, which were computed for three land cover surveys. This modelling was coupled with techniques for estimating fine sediment residence times, which are based on differences in the decay rates of three fallout radionuclides (Be-7, excess Pb-210 and Cs-137). Findings from this study demonstrate the need for more integrated approaches to better understand spatial patterns and timescales of sediment redistribution in river basins.

Smith, Hugh; Blake, William; Taylor, Alex

2013-04-01

362

Metal-contaminated sediments in a semi-closed basin: Implications for recovery  

Microsoft Academic Search

Sediment cores, collected from a contaminated zone in the Ria de Aveiro (Portugal), were sectioned, under nitrogen, and centrifuged to remove the pore waters. The sediment characteristics, including acid volatile sulphide (AVS) concentrations, were determined, together with total and available metals (Fe, Mn, Cd, Cu, Pb, Zn) and the total dissolved metals in the pore waters. Peak concentrations in total

P. Monterroso; P. Pato; M. E. Pereira; G. E. Millward; C. Vale; A. Duarte

2007-01-01

363

Sediment Dynamics and Sources in a Grazed Hardwood Rangeland Watershed1  

Microsoft Academic Search

From 1994 to 1998 we documented sediment transport dynamics and sources in a 137 ha grazed hardwood rangeland watershed on granitic soils at the San Joaquin Experimental Range in Madera County. Sediment transport for this watershed was determined by measuring total suspended solids, bedload and flow at an H-flume installed in 1994. Sediment movement as bedload is the primary means

Melvin R. George; Neil K. McDougald; Kenneth W. Tate; Royce Larsen

364

Bioturbation: minimal effects on the magnetic fabric of some natural and experimental sediments  

Microsoft Academic Search

Magnetic fabric measurements have been performed on three suites of sediment samples to contrast biologically disturbed and undisturbed sediments. The first of these analyses includes samples from laminated, relatively undisturbed and bioturbated, totally disturbed horizons found in an Athabasca Oil Sand core. The second includes samples from biologically undisturbed sediments from Mammoth Cave in Kentucky. The third includes evaluation of

Brooks B. Ellwood

1984-01-01

365

Sediment deposition and pedogenesis in exclosures in the Tigray highlands, Ethiopia  

Microsoft Academic Search

In the Tigray highlands of Northern Ethiopia, the establishment of exclosures (i.e., areas closed for grazing and agriculture) has become an important measure to combat land degradation and restore vegetative cover. Exclosures are commonly found on steep slopes and downslope from a sediment source area. In this study their sediment trapping capacity and controlling factors were investigated. Total sediment depth

Katrien Descheemaeker; Jan Nyssen; Joni Rossi; Jean Poesen; Mitiku Haile; Dirk Raes; Bart Muys; Jan Moeyersons; Seppe Deckers

2006-01-01

366

Effect of Sediment Organic Carbon on Survival of 'Hyalella azteca' Exposed to DDT and Endrin.  

National Technical Information Service (NTIS)

Sediment toxicity tests were conducted with the freshwater amphipod Hyalella azteca using sediments ranging in total organic carbon (TOC) concentration from 3 to 11% and spiked with either DDT or endrin. While the toxicity in the DDT-spiked sediment decre...

A. V. Nebeker G. S. Schuytema W. L. Griffis J. A. Barbitta L. A. Casey

1989-01-01

367

Recent increases in sediment and nutrient accumulation in Bear Lake, Utah/Idaho, USA  

USGS Publications Warehouse

This study examines historical changes in sediment and nutrient accumulation rates in Bear Lake along the northeastern Utah/Idaho border, USA. Two sediment cores were dated by measuring excess 210Pb activities and applying the constant rate of supply (CRS) dating model. Historical rates of bulk sediment accumulation were calculated based on the ages within the sediment cores. Bulk sediment accumulation rates increased throughout the last 100 years. According to the CRS model, bulk sediment accumulation rates were <25mg cm-2 year-1 prior to 1935. Between 1935 and 1980, bulk sediment accumulation rates increased to approximately 40mg cm -2 year-1. This increase in sediment accumulation probably resulted from the re-connection of Bear River to Bear Lake. Bulk sediment accumulation rates accelerated again after 1980. Accumulation rates of total phosphorus (TP), total nitrogen (TN), total inorganic carbon (TIC), and total organic carbon (TOC) were calculated by multiplying bulk sediment accumulation rates times the concentrations of these nutrients in the sediment. Accumulation rates of TP, TN, TIC, and TOC increased as a consequence of increased bulk sediment accumulation rates after the re-connection of Bear River with Bear Lake.

Smoak, J. M.; Swarzenski, P. W.

2004-01-01

368

Polycyclic Aromatic Hydrocarbons in Fishes and Sediments from the Guanabara Bay, Brazil  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) were identified and quantified in sediment and fish samples. The samples were analyzed by gas chromatography\\/mass spectrometry to gather information about the degree of contamination. PAH total concentration ranged from 79 to 487 ? g\\/kg dry weight in surficial sediment samples and from 4 to 53 ? g\\/kg in fish samples. Most sediment samples were classified

Taís Freitas da Silva; Débora de Almeida Azevedo; Francisco Radler de Aquino Neto

2007-01-01

369

Predicting Sediment Toxicity at Former Manufactured Gas Plants Using Equilibrium Partitioning Benchmarks for PAH Mixtures  

Microsoft Academic Search

This study was conducted to examine the application of Equilibrium Partitioning Sediment Benchmarks (ESBs) for assessing the toxicity of polycyclic aromatic hydrocarbons (PAHs) in sediments at former manufactured gas plant (MGP) and coke sites. Samples of freshwater sediment from four MGP and coke sites in the U.S. Northeast and Midwest were analyzed for 34 individual PAHs, total organic carbon, “black”

Susan B. Kane Driscoll; C. Bennett Amos; Margaret E. McArdle; Charles A. Menzie; Andrew Coleman

2009-01-01

370

Potential diagenetic and detrital sources for calcareous sediments from the Carlsberg Ridge, Indian Ocean  

Microsoft Academic Search

Six sediment cores from the Carlsberg Ridge (CR) were studied for elemental concentration, magnetic suscep- tibility (?), grain size and clay mineral distribution, and sedimentation rate to decipher possible detrital and diagenetic contributions. The sediments were characterized by very low ?, moderate total organic carbon, high CaCO3 content and high accumulation rate (3 cm\\/ kyr). Clay mineralogical and geochemical data

Anil B. Valsangkar; D. V. Borole; Archana S. Shejwalkar; Niyati G. Kalangutkar; Nelita O. Fernandes; Cliffa C. Dias

2009-01-01

371

Estimating Total Suspended Sediment Yield With Probability Sampling  

Microsoft Academic Search

ment record. The tested combinations of estimation technique and data collection method ranged from 70% below to 40% above the true value. Most of the estimates were less than 60% of the correct value. The variance of the estimators tended to increase as the accuracy improved, thus cancelling the benefits, and no approach emerged as the ideal choice for all

Robert B. Thomas

1985-01-01

372

Risk of Gastrointestinal Disease Associated with Exposure to Pathogens in the Sediments of the Lower Passaic River?  

PubMed Central

High levels of pathogenic microorganisms have been documented previously in waters of the Lower Passaic River in northern New Jersey. The purpose of this study was to characterize the microbial contamination of river sediments near combined sewer overflows (CSOs), a known source of pathogens. Concentrations of fecal coliform, total coliform, fecal Streptococcus, fecal Enterococcus, Pseudomonas aeruginosa, Staphylococcus aureus, Giardia lamblia, and Cryptosporidium parvum organisms were measured in 16 samples from three mudflat locations along the Lower Passaic River, as well as from an upstream location. Selected samples were also analyzed for antibiotic resistance. All of the samples contained high concentrations of total coliform, fecal coliform, fecal Streptococcus, and fecal Enterococcus organisms. Analysis of isolates of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli from several samples indicated that each strain was resistant to at least one antibiotic typically used in clinical settings. Eight of 16 samples contained Giardia, and one sample contained Cryptosporidium. With these sampling data, a quantitative microbial risk assessment was conducted to evaluate the probability of infection or illness resulting from incidental ingestion of contaminated sediments over a 1-year period. Three potential exposure scenarios were considered: visitor, recreator, and homeless person. Single-event risk was first evaluated for the three individual exposure scenarios; overall risk was then determined over a 1-year period using Monte Carlo techniques to characterize uncertainty. For fecal Streptococcus and Enterococcus, annualized risk estimates for gastrointestinal illness ranged from approximately 0.42 to 0.53 for recreators, 0.07 to 0.10 for visitors, and 0.62 to 0.72 for homeless individuals across the three sampling locations. Annualized risk of Giardia infection ranged from 0.14 to 0.64 for recreators, 0.01 to 0.1 for visitors, and 0.30 to 0.87 for homeless individuals, across all locations where detected. Cryptosporidium was detected at one location, and the corresponding annualized risk of infection was 0.32, 0.05, and 0.51 for recreators, visitors, and homeless individuals, respectively. This risk assessment suggests that pathogen-contaminated sediments near areas of CSO discharge in the Lower Passaic River could pose a health risk to individuals coming into contact with sediments in the mudflat areas.

Donovan, E. P.; Staskal, D. F.; Unice, K. M.; Roberts, J. D.; Haws, L. C.; Finley, B. L.; Harris, M. A.

2008-01-01

373

Comparison of mercury emission flux from the land surface to the atmosphere via water column, vegetative, and sediment column pathways  

NASA Astrophysics Data System (ADS)

The emission of mercury from the land surface can follow three pathways: 1) emission from the water column, 2) emission from exposed wetland sediments, and 3) transpiration through plants. In this poster, we present a comparison of all three emission pathways in Berry’s Creek, a tidal tributary to the Hackensack River, NJ USA. The Berry’s Creek watershed was historically subjected to discharges of mercury from a number of industrial facilities. Emission of mercury from the water column measured using a dynamic flux chamber ranged from -0.64 to 34 ng/m2-h a result of complex biogeochemical reactions between photoreactive dissolved organic carbon, ultraviolet light, and dissolved aqueous mercury. Solar radiation and DOC spectral slope appear to exert the strongest control on mercury emission, with solar radiation alone accounting for up to 98% of the diel changes in mercury emission. Emission of mercury from the common reed Phragmites australis measured using a whole-leaf, low dead-volume chamber ranged from -0.64 to 0.17 ng/m2-h. Solar radiation drives photosynthesis, transpiration, and mercury emission, though decreases in emission late in the day may reflect a more complex process. Mercury emission from mudflat sediments ranged from -0.37 to 11.3 ng/m2-h. Experiments blocking UV wavelengths indicate PAR wavelengths may play a significant role in promoting emission. Disturbance of sediment surface decreased emission, suggesting that the emission pathway is dependent on biological activity at the sediment surface or a chemical gradient established in the upper portion of the sediment column. Annual and diel cycles are considered in an estimation of the magnitude of total mercury emitted through each pathway over the duration of 1 year.

Peters, S. C.; Wollenberg, J.; Bubb, M. L.

2009-12-01

374

Intraoperative total serum calcium levels, unlike intraoperative intact PTH levels, do not correlate with cure of hyperparathyroidism 1 1 Presented at the annual meeting of the Association for Academic Surgery, Boston, MA, November 7–9, 2002  

Microsoft Academic Search

BackgroundIntraoperative intact parathyroid hormone (iPTH) monitoring is useful in the operative management of hyperparathyroidism. Recent studies suggest that measurement of intraoperative total serum calcium (TSC) levels may be a more cost effective and readily available method of intraoperative guidance during neck dissection than iPTH levels, the gold standard. We compared the accuracy of intraoperative TSC to iPTH in predicting surgical

Roderick M Quiros; Carl Valentin; Robert DeCresce; Richard A Prinz

2003-01-01

375

Characterization of polycyclic aromatic hydrocarbon bioavailability in estuarine sediments using thin-film extraction.  

PubMed

It is well documented that the bioavailability of hydrophobic organic chemicals (HOCs) can vary substantially among sediments. This makes risk assessments based on total sediment concentrations problematic. The present study investigates the application of thin-film solid-phase extraction to measure bioavailable concentrations of phenanthrene in estuarine sediment by comparing concentrations of phenanthrene in the amphipod Corophium colo and in thin ethylene/vinyl acetate films at different concentrations in three geochemically different sediments. For all sediment types, concentrations of phenanthrene in sediments and thin films followed linear relationships, indicating first-order exchange kinetics. Organism/thin-film concentration ratios did not vary systematically among sediment types but dropped significantly with increasing phenanthrene concentration in the sediments. While at low phenanthrene concentrations in the sediment fugacities of phenanthrene in the amphipods approached the fugacities in the thin films, they were significantly lower than those in the sediments at higher concentrations. While phenanthrene concentrations in the three sediment types were identical, biota sediment accumulation factors and concentrations in amphipods and thin films were consistently lower in sediments enriched with black carbon than in sediments with sedimentary organic matter bearing a more diagenetic organic signature. It is concluded that, for the range of concentrations tested, thin-film solid-phase extraction can be a useful tool in the characterization of differences in bioavailability of HOCs among sediment types. PMID:17521126

Golding, Christopher J; Gobas, Frank A P C; Birch, Gavin E

2007-05-01

376

A FIVE-YEAR RECORD OF SEDIMENTATION IN THE LOS ALAMOS RESERVOIR, NEW MEXICO, FOLLOWING THE CERRO GRANDE FIRE  

Microsoft Academic Search

comprising a coarse-grained delta. The total amount of sediment deposited in the reservoir during the 5-year period after the fire was ~43,100 m 3 , ~70% fine-grained sediment and ~30% coarse-grained sediment. About half of the post-fire sedimentation occurred in the first year. Delivery of fine-grained sediment to the reservoir decreased rapidly after the first year, although higher-intensity rainstorms occurred

Alexis Lavine; Gregory A. Kuyumjian; Steven L. Reneau; Danny Katzman; Daniel V. Malmon

377

Comparison of Mercury in Water, Bottom Sediment, and Zooplankton in Two Front Range Reservoirs in Colorado, 2008-09  

USGS Publications Warehouse

The U.S. Geological Survey, in cooperation with the Colorado Department of Public Health and Environment, conducted a study to investigate environmental factors that may contribute to the bioaccumulation of mercury in two Front Range reservoirs. One of the reservoirs, Brush Hollow Reservoir, currently (2009) has a fish-consumption advisory for mercury in walleye (Stizostedion vitreum), and the other, Pueblo Reservoir, which is nearby, does not. Water, bottom sediment, and zooplankton samples were collected during 2008 and 2009, and a sediment-incubation experiment was conducted in 2009. Total mercury concentrations were low in midlake water samples and were not substantially different between the two reservoirs. The only water samples with detectable methylmercury were collected in shallow areas of Brush Hollow Reservoir during spring. Mercury concentrations in reservoir bottom sediments were similar to those reported for stream sediments from unmined basins across the United States. Despite higher concentrations of fish-tissue mercury in Brush Hollow Reservoir, concentrations of methylmercury in sediment were as much as 3 times higher in Pueblo Reservoir. Mercury concentrations in zooplankton were at the low end of concentrations reported for temperate lakes in the Northeastern United States and were similar between sites, which may reflect the seasonal timing of sampling. Factors affecting bioaccumulation of mercury were assessed, including mercury sources, water quality, and reservoir characteristics. Atmospheric deposition was determined to be the dominant source of mercury; however, due to the proximity of the reservoirs, atmospheric inputs likely are similar in both study areas. Water-quality constituents commonly associated with elevated concentrations of mercury in fish (pH, alkalinity, sulfate, nutrients, and dissolved organic carbon) did not appear to explain differences in fish-tissue mercury concentrations between the reservoirs. Low methylmercury concentrations in hypolimnetic water indicate low potential for increased methylmercury production following the development of anoxic conditions in summer. Based on the limited dataset, water-level fluctuations and shoreline characteristics appear to best explain differences in fish-tissue mercury concentrations between the reservoirs. Due to the shallow depth and the large annual water-level fluctuations at Brush Hollow Reservoir, proportionally larger areas of shoreline at Brush Hollow Reservoir are subjected to annual reflooding compared to Pueblo Reservoir. Moreover, presence of macrophyte beds and regrowth of terrestrial vegetation likely increase the organic content of near-shore sediments in Brush Hollow Reservoir, which may stimulate methylmercury production in littoral areas subject to reflooding. Results of a laboratory incubation experiment were consistent with this hypothesis.

Mast, M. Alisa; Krabbenhoft, David P.

2010-01-01

378

Sediment studies at Bikini Atoll part 2. inventories of transuranium elements in surface sediments  

SciTech Connect

This is the second of three reports on Bikini sediment studies, which discusses the concentrations and inventories of {sup 241}Am and {sup 239+240}Pu in sediments from the lagoon. Surface sediment samples were collected from 87 locations over the entire lagoon at Bikini Atoll during 1979. The collections were made to map the distribution of long-lived radionuclides associated with the bottom material and to show what modifications occurred in the composition of the sediment as a result of the testing program. Present inventories for {sup 241}Am and {sup 239+240}Pu in the surface 2 cm of sediment are estimated to be 14 and 17 TBq, respectively. These values are estimated to represent only 14% of the total inventory in the sediment column. Sediment inventories of {sup 239+240}Pu and {sup 241}Am are changing only slowly with time through chemical- physical processes that continuously mobilize small amounts of the transuranics to the water column. The lowest concentrations and inventories are associated with deposits logoonward of the eastern reef.

Noshkin, V.E.; Eagle, R.J.; Wong, K.M.; Robison, W.L.

1997-10-01

379

Analytical Ultracentrifugation: Sedimentation Velocity and Sedimentation Equilibrium  

PubMed Central

Analytical ultracentrifugation (AUC) is a versatile and powerful method for the quantitative analysis of macromolecules in solution. AUC has broad applications for the study of biomacromolecules in a wide range of solvents and over a wide range of solute concentrations. Three optical systems are available for the analytical ultracentrifuge (absorbance, interference and fluorescence) that permit precise and selective observation of sedimentation in real time. In particular, the fluorescence system provides a new way to extend the scope of AUC to probe the behavior of biological molecules in complex mixtures and at high solute concentrations. In sedimentation velocity, the movement of solutes in high centrifugal fields is interpreted using hydrodynamic theory to define the size, shape and interactions of macromolecules. Sedimentation equilibrium is a thermodynamic method where equilibrium concentration gradients at lower centrifugal fields are analyzed to define molecule mass, assembly stoichiometry, association constants and solution nonideality. Using specialized sample cells and modern analysis software, researchers can use sedimentation velocity to determine the homogeneity of a sample and define whether it undergoes concentration-dependent association reactions. Subsequently, more thorough model-dependent analysis of velocity and equilibrium experiments can provide a detailed picture of the nature of the species present in solution and their interactions.

Cole, James L.; Lary, Jeffrey W.; Moody, Thomas; Laue, Thomas M.

2009-01-01

380

Controls on uranium distribution in lake sediments  

NASA Astrophysics Data System (ADS)

Uranium geochemistry has been investigated in three acid lakes located on the Canadian Shield and one circumneutral lake in the Appalachian Region of Eastern Canada. In all Shield lakes, dissolved U concentrations were higher in the porewater than in the overlying water. In one of them, whose hypolimnion is perennially oxic, U released to porewater at depths of Fe remobilization was removed from the porewater at depths of Fe oxyhydroxides precipitation; these similarities in the U and Fe profiles indicate that part of the U becomes associated to Fe oxyhydroxides. The dissolved U and Fe profiles in the other two Shield lakes, whose hypolimnions were anoxic when sampled, did not show any significant recycling of these elements in the vicinity of the sediment-water interface and both elements diffused from the sediment to the overlying water. In contrast, in the Appalachian Lake, dissolved U concentrations were higher in the overlying water than in porewater, strongly decreased at the vicinity of the sediment-water interface and then remained relatively constant with sediment depth. Diagenetic modeling of the porewater U profiles, assuming steady-state, reveals that authigenic U always represented ?3% of the total U concentration in the sediments of all lakes. This observation indicates that diagenetic reactions involving U are not quantitatively important and that most of the U was delivered to the sediments at our study sites as particulate U and not through diffusion across the sediment-water interface, as is seen in continental margin sediments. Comparison of the U:C org and U:Fe molar ratios in diagenetic material collected across the sediment-water interface with Teflon sheets and in surface sediments (0-0.5 cm) of the lake having a perennially oxic hypolimnion suggest that solid phase U was mainly bound to organic matter originating from the watershed; a strong statistical correlation between sediment non-lithogenic U and C org in the Appalachian Lake supports this contention. Thermodynamic calculations of saturation states suggest that dissolved U was not removed from porewater through precipitation of UO 2(s), U 3O 7(s) and U 3O 8(s) as previously proposed in the literature.

Chappaz, Anthony; Gobeil, Charles; Tessier, André

2010-01-01

381

Toxicity and Geochemistry of Missouri Cave Stream Sediments  

NASA Astrophysics Data System (ADS)

Water and sediment quality are among the most important variables affecting the survival of stygobites. In Tumbling Creek Cave, Taney County Missouri the population of the endangered