Tropical Cyclones as a Driver of Global Sediment Flux

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Feasibility of estimate sediment yield in the non-sediment monitoring station area - A case study of Alishan River watershed,Taiwan

NASA Astrophysics Data System (ADS)

Chang, ChiaChi; Chan, HsunChuan; Jia, YaFei; Zhang, YaoXin

2017-04-01

Due to the steep topography, frail geology and concentrated rainfall in wet season, slope disaster occurred frequently in Taiwan. In addition, heavy rainfall induced landslides in upper watersheds. The sediment yield on the slopeland affects the sediment transport in the river. Sediment deposits on the river bed reduce the river cross section and change the flow direction. Furthermore, it generates risks to residents' lives and property in the downstream. The Taiwanese government has been devoting increasing efforts on the sedimentary management issues and on reduction in disaster occurrence. However, due to the limited information on the environmental conditions in the upper stream, it is difficult to set up the sedimentary monitoring equipment. This study used the upper stream of the Qingshuei River, the Alishan River, as a study area. In August 2009, Typhoon Morakot caused the sedimentation of midstream and downstream river courses in the Alishan River. Because there is no any sediment monitoring stations within the Alishan River watershed, the sediment yield values are hard to determine. The objective of this study is to establish a method to analyze the event-landslide sediment transport in the river on the upper watershed. This study numerically investigated the sediment transport in the Alishan River by using the KINEROS 2 model developed by the United States Department of Agriculture and the CCHE1D model developed by the National Center for Computational Hydroscience and Engineering. The simulated results represent the morphology changes in the Alishan River during the typhoon events. The results consist of a critical strategy reference for the sedimentary management for the Alishan River watershed.

Predicting improved optical water quality in rivers resulting from soil conservation actions on land.

PubMed

Dymond, J R; Davies-Colley, R J; Hughes, A O; Matthaei, C D

2017-12-15

Deforestation in New Zealand has led to increased soil erosion and sediment loads in rivers. Increased suspended fine sediment in water reduces visual clarity for humans and aquatic animals and reduces penetration of photosynthetically available radiation to aquatic plants. To mitigate fine-sediment impacts in rivers, catchment-wide approaches to reducing soil erosion are required. Targeting soil conservation for reducing sediment loads in rivers is possible through existing models; however, relationships between sediment loads and sediment-related attributes of water that affect both ecology and human uses of water are poorly understood. We present methods for relating sediment loads to sediment concentration, visual clarity, and euphotic depth. The methods require upwards of twenty concurrent samples of sediment concentration, visual clarity, and euphotic depth at a river site where discharge is measured continuously. The sediment-related attributes are related to sediment concentration through regressions. When sediment loads are reduced by soil conservation action, percentiles of sediment concentration are necessarily reduced, and the corresponding percentiles of visual clarity and euphotic depth are increased. The approach is demonstrated on the Wairua River in the Northland region of New Zealand. For this river we show that visual clarity would increase relatively by approximately 1.4 times the relative reduction of sediment load. Median visual clarity would increase from 0.75m to 1.25m (making the river more often suitable for swimming) after a sediment load reduction of 50% associated with widespread soil conservation on pastoral land. Likewise euphotic depth would increase relatively by approximately 0.7 times the relative reduction of sediment load, and the median euphotic depth would increase from 1.5m to 2.0m with a 50% sediment load reduction. Copyright © 2017 Elsevier B.V. All rights reserved.

Magnetic properties of Surabaya river sediments, East Java, Indonesia

NASA Astrophysics Data System (ADS)

Mariyanto, Bijaksana, Satria

2017-07-01

Surabaya river is one of urban rivers in East Java Province, Indonesia that is a part of Brantas river that flows in four urban and industrial cities of Mojokerto, Gresik, Sidoarjo, and Surabaya. The urban populations and industries along the river pose serious threat to the river mainly for their anthropogenic pollutants. This study aims to characterize the magnetic properties of sediments in various locations along Surabaya river and correlate these magnetic properties to the level of pollution along the river. Samples are taken and measured through a series of magnetic measurements. The mass-specific magnetic susceptibility of sediments ranges from 259.4 to 1134.8 × 10-8 m3kg-1. The magnetic minerals are predominantly PSD to MD magnetite with the grain size range from 6 to 14 μm. The mass-specific magnetic susceptibility tends to decreases downstream as accumulation of magnetic minerals in sediments is affected not only by the amount of household and industrial wastes but also by sediment dredging, construction of embankments, and extensive erosion arround the river. Sediments located in the industrial zone on the upstream area tend to have higher mass-specific magnetic susceptibility than in the non-industrial zones on the downstream area.

Variation of River Islands around a Large City along the Yangtze River from Satellite Remote Sensing Images

PubMed Central

Shi, Haiyun; Gao, Chao; Dong, Changming; Xia, Changshui; Xu, Guanglai

2017-01-01

River islands are sandbars formed by scouring and silting. Their evolution is affected by several factors, among which are runoff and sediment discharge. The spatial-temporal evolution of seven river islands in the Nanjing Section of the Yangtze River of China was examined using TM (Thematic Mapper) and ETM (Enhanced Thematic Mapper)+ images from 1985 to 2015 at five year intervals. The following approaches were applied in this study: the threshold value method, binarization model, image registration, image cropping, convolution and cluster analysis. Annual runoff and sediment discharge data as measured at the Datong hydrological station upstream of Nanjing section were also used to determine the roles and impacts of various factors. The results indicated that: (1) TM/ETM+ images met the criteria of information extraction of river islands; (2) generally, the total area of these islands in this section and their changing rate decreased over time; (3) sediment and river discharge were the most significant factors in island evolution. They directly affect river islands through silting or erosion. Additionally, anthropocentric influences could play increasingly important roles. PMID:28953218

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

PubMed

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

2016-02-01

In the Danube River Basin multiple pressures affect the river system as a consequence of river engineering works, altering both the river hydrodynamics and morphodynamics. The main objective of this paper is to identify the effects of hydropower development, flood protection and engineering works for navigation on the Danube and to examine specific impacts of these developments on sediment transport and river morphology. Whereas impoundments are characterised by deposition and an excess of sediment with remobilisation of fine sediments during severe floods, the remaining five free flowing sections of the Danube are experiencing river bed erosion of the order of several centimetres per year. Besides the effect of interruption of the sediment continuum, river bed degradation is caused by an increase in the sediment transport capacity following an increase in slope, a reduction of river bed width due to canalisation, prohibition of bank erosion by riprap or regressive erosion following base level lowering by flood protection measures and sediment dredging. As a consequence, the groundwater table is lowered, side-arms are disconnected, instream structures are lost and habitat quality deteriorates affecting the ecological status of valuable floodplains. The lack of sediments, together with cutting off meanders, leads also to erosion of the bed of main arms in the Danube Delta and coastal erosion. This paper details the causes and effects of river engineering measures and hydromorphological changes for the Danube. It highlights the importance of adopting a basin-wide holistic approach to river management and demonstrates that past management in the basin has been characterised by a lack of integration. To-date insufficient attention has been paid to the wide-ranging impacts of river engineering works throughout the basin: from the basin headwaters to the Danube Delta, on the Black Sea coast. This highlights the importance of new initiatives that seek to advance knowledge exchange and knowledge transfer within the basin to reach the goal of integrated basin management. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization of heavy metal concentrations in the sediments of three freshwater rivers in Huludao City, Northeast China.

PubMed

Zheng, Na; Wang, Qichao; Liang, Zhongzhu; Zheng, Dongmei

2008-07-01

Wuli River, Cishan River, and Lianshan River are three freshwater rivers flowing through Huludao City, in a region of northeast China strongly affected by industrialization. Contamination assessment has never been conducted in a comprehensive way. For the first time, the contamination of three rivers impacted by different sources in the same city was compared. This work investigated the distribution and sources of Hg, Pb, Cd, Zn and Cu in the surface sediments of Wuli River, Cishan River, and Lianshan River, and assessed heavy metal toxicity risk with the application of two different sets of Sediment Quality Guideline (SQG) indices (effect range low/effect range median values, ERL/ERM; and threshold effect level/probable effect level, TEL/PEL). Furthermore, this study used a toxic unit approach to compare and gauge the individual and combined metal contamination for Hg, Pb, Cd, Zn and Cu. Results showed that Hg contamination in the sediments of Wuli River originated from previous sediment contamination of the chlor-alkali producing industry, and Pb, Cd, Zn and Cu contamination was mainly derived from atmospheric deposition and unknown small pollution sources. Heavy metal contamination to Cishan River sediments was mainly derived from Huludao Zinc Plant, while atmospheric deposition, sewage wastewater and unknown small pollution were the primary sources for Lianshan River. The potential acute toxicity in sediment of Wuli River may be primarily due to Hg contamination. Hg is the major toxicity contributor, accounting for 53.3-93.2%, 7.9-54.9% to total toxicity in Wuli River and Lianshan River, respectively, followed by Cd. In Cishan River, Cd is the major sediment toxicity contributor, however, accounting for 63.2-66.9% of total toxicity.

Catchment-scale environmental controls of sediment-associated contaminant dispersal

NASA Astrophysics Data System (ADS)

Macklin, Mark

2010-05-01

Globally river sediment associated contaminants, most notably heavy metals, radionuclides, Polychlorinated Biphenyls (PCBs), Organochlorine pesticides (OCs) and phosphorous, constitute one the most significant long-term risks to ecosystems and human health. These can impact both urban and rural areas and, because of their prolonged environmental residence times, are major sources of secondary pollution if contaminated soil and sediment are disturbed by human activity or by natural processes such as water or wind erosion. River catchments are also the primary source of sediment-associated contaminants to the coastal zone, and to the ocean, and an understanding of the factors that control contaminated sediment fluxes and delivery in river systems is essential for effective environmental management and protection. In this paper the catchment-scale controls of sediment-associated contaminant dispersal are reviewed, including climate-related variations in flooding regime, land-use change, channel engineering, restoration and flood defence. Drawing on case studies from metal mining impacted catchments in Bolivia (Río Pilcomayo), Spain (Río Guadiamar), Romania (River Tisa) and the UK (River Swale) some improved methodologies for identifying, tracing, modelling and managing contaminated river sediments are proposed that could have more general application in similarly affected river systems worldwide.

Toxic assessment of the leachates of paddy soils and river sediments from e-waste dismantling sites to microalga, Pseudokirchneriella subcapitata.

PubMed

Nie, Xiangping; Fan, Canpeng; Wang, Zhaohui; Su, Tian; Liu, Xinyu; An, Taicheng

2015-01-01

The potential adverse effects of e-waste recycling activity on environment are getting increasing concern. In this work, a model alga, Pseudokirchneriella subcapitata, was employed to assess the toxic effects of the leachates of paddy soils and river sediments collected from e-waste dismantling sites. Chemical analysis of the paddy soils and river sediments and their leachates were carried out and the growth rate, chlorophyll a fluorescence and anti-oxidative systems of the alga were measured. Results showed that two leachates decreased the amount of PSII active reaction centers and affected photosynthesis performance, interfered with chlorophyll synthesis and inhibited algal growth. Some chemical pollutants in the sediments and soils such as polybrominated diphenyl ethers (PBDEs) and metals derived from e-waste recycling activity may impose oxidative stress on algae and affect the activity of anti-oxidative enzymes such as GST, SOD, CAT and APX. The leachates of both river sediments and paddy soils are potentially toxic to the primary producers, P. subcapitata and the leachate from sediments was more deleterious than that from soils. Copyright © 2014 Elsevier Inc. All rights reserved.

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

USGS Publications Warehouse

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

2016-02-04

Comparisons of concentrations and loads from EWI samples collected from different transects within a study site resulted in few significant differences, but comparisons are limited by small sample sizes and large within-transect variability. When comparing the Missouri River upstream transect to the chute inlet transect, similar results were determined in 2012 as were determined in 2008—the chute inlet affected the amount of sediment entering the chute from the main channel. In addition, the Kansas chute is potentially affecting the sediment concentration within the Missouri River main channel, but small sample size and construction activities within the chute limit the ability to fully understand either the effect of the chute in 2012 or the effect of the chute on the main channel during a year without construction. Finally, some differences in SSC were detected between the Missouri River upstream transects and the chute downstream transects; however, the effect of the chutes on the Missouri River main-channel sediment transport was difficult to isolate because of construction activities and sampling variability.

Use of Mössbauer spectroscopy to determine the effect of salinity on the speciation of triorganotins in Anacostia River sediments

NASA Astrophysics Data System (ADS)

Eng, George; Song, Xueqing; May, Leopold

2006-06-01

The speciation of several tributyltin and triphenyltin compounds under varying salinity conditions (0, 20, 40 and 60%) was studied by Mössbauer spectroscopy in both anaerobic and aerobic Anacostia River sediments. The Mössbauer spectral parameters of the spiked sediments indicated that changes in the salinity did not affect the speciation of the tin compounds in either aerobic or anaerobic sediments.

Use of Mössbauer spectroscopy to determine the effect of salinity on the speciation of triorganotins in Anacostia River sediments

NASA Astrophysics Data System (ADS)

Eng, George; Song, Xueqing; May, Leopold

The speciation of several tributyltin and triphenyltin compounds under varying salinity conditions (0, 20, 40 and 60%) was studied by Mössbauer spectroscopy in both anaerobic and aerobic Anacostia River sediments. The Mössbauer spectral parameters of the spiked sediments indicated that changes in the salinity did not affect the speciation of the tin compounds in either aerobic or anaerobic sediments.

Summary of Bed-Sediment Measurements Along the Platte River, Nebraska, 1931-2009

USGS Publications Warehouse

Kinzel, P.J.; Runge, J.T.

2010-01-01

Rivers are conduits for water and sediment supplied from upstream sources. The sizes of the sediments that a river bed consists of typically decrease in a downstream direction because of natural sorting. However, other factors can affect the caliber of bed sediment including changes in upstream water-resource development, land use, and climate that alter the watershed yield of water or sediment. Bed sediments provide both a geologic and stratigraphic record of past fluvial processes and quantification of current sediment transport relations. The objective of this fact sheet is to describe and compare longitudinal measurements of bed-sediment sizes made along the Platte River, Nebraska from 1931 to 2009. The Platte River begins at the junction of the North Platte and South Platte Rivers near North Platte, Nebr. and flows east for approximately 500 kilometers before joining the Missouri River at Plattsmouth, Nebr. The confluence of the Loup River with the Platte River serves to divide the middle (or central) Platte River (the Platte River upstream from the confluence with the Loup River) and lower Platte River (the Platte River downstream from the confluence with Loup River). The Platte River provides water for a variety of needs including: irrigation, infiltration to public water-supply wells, power generation, recreation, and wildlife habitat. The Platte River Basin includes habitat for four federally listed species including the whooping crane (Grus americana), interior least tern (Sterna antillarum), piping plover (Charadrius melodus), and pallid sturgeon (Scaphirhynchus albus). A habitat recovery program for the federally listed species in the Platte River was initiated in 2007. One strategy identified by the recovery program to manage and enhance habitat is the manipulation of streamflow. Understanding the longitudinal and temporal changes in the size gradation of the bed sediment will help to explain the effects of past flow regimes and anticipated manipulation of streamflows on the channel morphology and habitat.

Large-scale dam removal on the Elwha River, Washington, USA: river channel and floodplain geomorphic change

USGS Publications Warehouse

East, Amy E.; Pess, George R.; Bountry, Jennifer A.; Magirl, Christopher S.; Ritchie, Andrew C.; Logan, Joshua; Randle, Timothy J.; Mastin, Mark C.; Minear, Justin T.; Duda, Jeffrey J.; Liermann, Martin C.; McHenry, Michael L.; Beechie, Timothy J.; Shafroth, Patrick B.

2015-01-01

As 10.5 million t (7.1 million m3) of sediment was released from two former reservoirs, downstream dispersion of a sediment wave caused widespread bed aggradation of ~ 1 m (greater where pools filled), changed the river from pool–riffle to braided morphology, and decreased the slope of the lowermost river. The newly deposited sediment, which was finer than most of the pre-dam-removal bed, formed new bars (largely pebble, granule, and sand material), prompting aggradational channel avulsion that increased the channel braiding index by almost 50%. As a result of mainstem bed aggradation, floodplain channels received flow and accumulated new sediment even during low to moderate flow conditions. The river system showed a two- to tenfold greater geomorphic response to dam removal (in terms of bed elevation change magnitude) than it had to a 40-year flood event four years before dam removal. Two years after dam removal began, as the river had started to incise through deposits of the initial sediment wave, ~ 1.2 million t of new sediment (~ 10% of the amount released from the two reservoirs) was stored along 18 river km of the mainstem channel and 25 km of floodplain channels. The Elwha River thus was able to transport most of the released sediment to the river mouth. The geomorphic alterations and changing bed sediment grain size along the Elwha River have important ecological implications, affecting aquatic habitat structure, benthic fauna, salmonid fish spawning and rearing potential, and riparian vegetation. The response of the river to dam removal represents a unique opportunity to observe and quantify fundamental geomorphic processes associated with a massive sediment influx, and also provides important lessons for future river-restoration endeavors.

Dynamics of dissolved organic matter in riverine sediments affected by weir impoundments: Production, benthic flux, and environmental implications.

PubMed

Chen, Meilian; Kim, Sung-Han; Jung, Heon-Jae; Hyun, Jung-Ho; Choi, Jung Hyun; Lee, Hyo-Jin; Huh, In-Ae; Hur, Jin

2017-09-15

In order to understand the characteristics and dynamics of dissolved organic matter (DOM) in the sediment of rivers affected by impoundments, we examined the vertical profiles and the benthic fluxes of DOM in four different core sediments located at upstream sites of weirs in major rivers of South Korea. In three out of four sites, exponential accumulation of dissolved organic carbon (DOC) with depth was observed with the signature of seasonal variability. Except for the site displaying a below-detection limit of Fe(II), the general accumulation trends of DOC with depth was concurrent with the increases of Fe(II) and NH 4 + and the decrease of PO 4 3- , signifying a close linkage of the DOM dynamics with anaerobic respiration via iron reduction, an important early diagenesis pathway. The estimated benthic fluxes from the cores revealed that the sediments likely serve as DOC, chromophoric DOM (CDOM), and fluorescent DOM (FDOM) sources to the overlying water. The benthic effluxes based on DOC were comparable to the ranges previously reported in lake and coastal areas, and those of CDOM and FDOM showed even higher levels. These findings imply that impoundment-affected river systems would change the DOM composition of the overlying water, ultimately influencing the subsequent water treatment processes such as disinfection byproducts production and membrane fouling. A simple mass balance model indicated that the impoundment-affected river sediments may operate as a net carbon sink in the environments due to a greater extent of sedimentation compared to the estimated benthic efflux and sediment biological respiration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sediment storage time in a simulated meandering river's floodplain, comparisons of point bar and overbank deposits

NASA Astrophysics Data System (ADS)

Ackerman, T. R.; Pizzuto, J. E.

2016-12-01

Sediment may be stored briefly or for long periods in alluvial deposits adjacent to rivers. The duration of sediment storage may affect diagenesis, and controls the timing of sediment delivery, affecting the propagation of upland sediment signals caused by tectonics, climate change, and land use, and the efficacy of watershed management strategies designed to reduce sediment loading to estuaries and reservoirs. Understanding the functional form of storage time distributions can help to extrapolate from limited field observations and improve forecasts of sediment loading. We simulate stratigraphy adjacent to a modeled river where meander migration is driven by channel curvature. The basal unit is built immediately as the channel migrates away, analogous to a point bar; rules for overbank (flood) deposition create thicker deposits at low elevations and near the channel, forming topographic features analogous to natural levees, scroll bars, and terraces. Deposit age is tracked everywhere throughout the simulation, and the storage time is recorded when the channel returns and erodes the sediment at each pixel. 210 ky of simulated run time is sufficient for the channel to migrate 10,500 channel widths, but only the final 90 ky are analyzed. Storage time survivor functions are well fit by exponential functions until 500 years (point bar) or 600 years (overbank) representing the youngest 50% of eroded sediment. Then (until an age of 12 ky, representing the next 48% (point bar) or 45% (overbank) of eroding sediment), the distributions are well fit by heavy tailed power functions with slopes of -1 (point bar) and -0.75 (overbank). After 12 ky (6% of model run time) the remainder of the storage time distributions become exponential (light tailed). Point bar sediment has the greatest chance (6%) of eroding at 120 years, as the river reworks recently deposited point bars. Overbank sediment has an 8% chance of eroding after 1 time step, a chance that declines by half after 3 time steps. The high probability of eroding young overbank deposits occurs as the river reworks recently formed natural levees. These results show that depositional environment affects river floodplain storage times shorter than a few centuries, and suggest that a power law distribution with a truncated tail may be the most reasonable functional fit.

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

EPA Science Inventory

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

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

USGS Publications Warehouse

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

2016-12-20

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

Landscape level influence: aquatic primary production in the Colorado River of Glen and Grand canyons

NASA Astrophysics Data System (ADS)

Yard, M. D.; Kennedy, T.; Yackulic, C. B.; Bennett, G. E.

2012-12-01

Irregular features common to canyon-bound regions intercept solar incidence (photosynthetic photon flux density [PPFD: μmol m-2 s-1]) and can affect ecosystem energetics. The Colorado River in Grand Canyon is topographically complex, typical of most streams and rivers in the arid southwest. Dam-regulated systems like the Colorado River have reduced sediment loads, and consequently increased water transparency relative to unimpounded rivers; however, sediment supply from tributaries and flow regulation that affects erosion and subsequent sediment transport, interact to create spatial and temporal variation in optical conditions in this river network. Solar incidence and suspended sediment loads regulate the amount of underwater light available for aquatic photosynthesis in this regulated river. Since light availability is depth dependent (Beer's law), benthic algae is often exposed to varying levels of desiccation or reduced light conditions due to daily flow regulation, additional factors that further constrain aquatic primary production. Considerable evidence suggests that the Colorado River food web is now energetically dependent on autotrophic production, an unusual condition since large river foodwebs are typically supported by allochthonous carbon synthesized and transported from terrestrial environments. We developed a mechanistic model to account for these regulating factors to predict how primary production might be affected by observed and alternative flow regimes proposed as part of ongoing adaptive management experimentation. Inputs to our model include empirical data (suspended sediment and temperature), and predictive relationships: 1) solar incidence reaching the water surface (topographic complexity), 2) suspended sediment-light extinction relationships (optical properties), 3) unsteady flow routing model (stage-depth relationship), 4) channel morphology (photosynthetic area), and 5) photosynthetic-irradiant response for dominant algae (Cladophora glomerata and associated epiphytes). Initial findings suggest that aquatic primary production varies spatially and temporally in response to natural processes occurring at varying spatial scales and that flow regulation per se has only a minor effect on primary production. All of these physical drivers combined are likely to structure the abundance, distribution, and interaction of aquatic biota found in this ecosystem.

Human impacts on fluvial systems - A small-catchment case study

NASA Astrophysics Data System (ADS)

Pöppl, Ronald E.; Glade, Thomas; Keiler, Margreth

2010-05-01

Regulations of nearly two-thirds of the rivers worldwide have considerable influences on fluvial systems. In Austria, nearly any river (or) catchment is affected by humans, e.g. due to changing land-use conditions and river engineering structures. Recent studies of human impacts on rivers show that morphologic channel changes play a major role regarding channelization and leveeing, land-use conversions, dams, mining, urbanization and alterations of natural habitats (ecomorphology). Thus 'natural (fluvial) systems' are scarce and humans are almost always inseparably interwoven with them playing a major role in altering them coincidentally. The main objective of this study is to identify human effects (i.e. different land use conditions and river engineering structures) on river bed sediment composition and to delineate its possible implications for limnic habitats. The study area watersheds of the 'Fugnitz' River (~ 140km²) and the 'Kaja' River (~ 20km²) are located in the Eastern part of the Bohemian Massif in Austria (Europe) and drain into the 'Thaya' River which is the border river to the Czech Republic in the north of Lower Austria. Furthermore the 'Thaya' River is eponymous for the local National Park 'Nationalpark Thayatal'. In order to survey river bed sediment composition and river engineering structures facies mapping techniques, i.e. river bed surface mapping and ecomorphological mapping have been applied. Additionally aerial photograph and airborne laserscan interpretation has been used to create land use maps. These maps have been integrated to a numerical DEM-based spatial model in order to get an impression of the variability of sediment input rates to the river system. It is hypothesized that this variability is primarily caused by different land use conditions. Finally river bed sites affected by river engineering structures have been probed and grain size distributions have been analyzed. With these data sedimentological and ecological/ecomorphological effects of various river engineering structures (i.e. dams, weirs, river bank- and river bed protection works) on river bed sediment composition and on limnic habitats are evaluated. First results reveal that 'land use' is a dominant factor concerning river bed sediment composition and limnic habitat conditions. Further outcomes will be presented on European Geosciences Union General Assembly, 2010.

Legacy Sediments in U.S. River Environments: Atrazine and Aggradation to Zinc and Zoobenthos

NASA Astrophysics Data System (ADS)

Wohl, E.

2014-12-01

Legacy sediments are those that are altered by human activities. Alterations include (i) human-caused aggradation (and subsequent erosion), such as sediment accumulating upstream from relict or contemporary dams, (ii) human-caused lack of continuing deposition that results in changing moisture and nutrient levels within existing sediments, such as on floodplains that no longer receive lateral or vertical accretion deposits because of levees, bank stabilization, and other channel engineering, and (iii) human-generated contaminants such as PCBs and pesticides that adsorb to fine sediment. Existing estimates of human alterations of river systems suggest that legacy sediments are ubiquitous. Only an estimated 2% of river miles in the United States are not affected by flow regulation that alters sediment transport, for example, and less than half of major river basins around the world are minimally altered by flow regulation. Combined with extensive but poorly documented reduction in floodplain sedimentation, as well as sediment contamination by diverse synthetic compounds, excess nutrients, and heavy metals, these national and global estimates suggest that legacy sediments now likely constitute a very abundant type of fluvial sediment. Because legacy sediments can alter river form and function for decades to centuries after the cessation of the human activity that created the legacy sediments, river management and restoration must be informed by accurate knowledge of the distribution and characteristics of legacy sediments. Geomorphologists can contribute understanding of sediment dynamics, including: the magnitude, frequency, and duration of flows that mobilize sediments with adsorbed contaminants; sites where erosion and deposition are most likely to occur under specified flow and sediment supply; residence time of sediments; and the influence of surface and subsurface water fluxes on sediment stability and geochemistry.

Estimating sediment budgets at the interface between rivers and estuaries with application to the Sacramento-San Joaquin River Delta

USGS Publications Warehouse

Wright, S.A.; Schoellhamer, D.H.

2005-01-01

[1] Where rivers encounter estuaries, a transition zone develops where riverine and tidal processes both affect sediment transport processes. One such transition zone is the Sacramento-San Joaquin River Delta, a large, complex system where several rivers meet to form an estuary (San Francisco Bay). Herein we present the results of a detailed sediment budget for this river/estuary transitional system. The primary regional goal of the study was to measure sediment transport rates and pathways in the delta in support of ecosystem restoration efforts. In addition to achieving this regional goal, the study has produced general methods to collect, edit, and analyze (including error analysis) sediment transport data at the interface of rivers and estuaries. Estimating sediment budgets for these systems is difficult because of the mixed nature of riverine versus tidal transport processes, the different timescales of transport in fluvial and tidal environments, and the sheer complexity and size of systems such as the Sacramento-San Joaquin River Delta. Sediment budgets also require error estimates in order to assess whether differences in inflows and outflows, which could be small compared to overall fluxes, are indeed distinguishable from zero. Over the 4 year period of this study, water years 1999-2002, 6.6 ?? 0.9 Mt of sediment entered the delta and 2.2 ?? 0.7 Mt exited, resulting in 4.4 ?? 1.1 Mt (67 ?? 17%) of deposition. The estimated deposition rate corresponding to this mass of sediment compares favorably with measured inorganic sediment accumulation on vegetated wetlands in the delta.

Fine sediment trapping in river lateral cavities

NASA Astrophysics Data System (ADS)

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

2016-12-01

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

Anthropogenic impact on biogenic substance distribution and bacterial community in sediment along the Yarlung Tsangpo River on Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Wang, C.; Peifang, W.; Wang, X.; Hou, J.; Miao, L.

2017-12-01

Lotic river system plays an important part in water-vapor transfer and biogenic substances migration and transformation. Anthropogenic activities, including wastewater discharging and river damming, have altered river ecosystem and continuum. However, as the longest alpine river in China and suffered from increasing anthropogenic activities, the Yarlung Tsangpo River has been rarely studied. Recently, more attention has also been paid to the bacteria in river sediment as they make vital contributions to the biogeochemical nutrient cycling. Here, the distribution of biogenic substances, including nitrogen, phosphorus, silicon and carbon, was explored in both water and sediment of the Yarlung Tsangpo River. By using the next generation 16S rRNA sequencing, the bacterial diversity and structure in river sediment were presented. The results indicated that the nutrient concentrations increased in densely populated sites, revealing that biogenic substance distribution corresponded with the intensity of anthropogenic activity along the river. Nitrogen, phosphorus, silicon and carbon in water and sediment were all retained by the Zangmu Dam which is the only dam in the mainstream of the river. Moreover, the river damming decreased the biomass and diversity of bacteria in sediment, but no significant alteration of community structure was observed upstream and downstream of the dam. The most dominant bacteria all along the river was Proteobacteria. Meanwhile, Verrucomicrobia and Firmicutes also dominated the community composition in upstream and downstream of the river, respectively. In addition, total organic carbon (TOC) was proved to be the most important environmental factor shaping the bacterial community in river sediment. Our study offered the preliminary insights into the biogenic substance distribution and bacterial community in sediment along an alpine river which was affected by anthropogenic activities. In the future, more studies are needed to reveal the relationship between anthropogenic activity, biogenic substance cycling and bacterial community, especially along the alpine rivers.

Transport and sources of sediment in the Missouri River between Garrison Dam and the headwaters of Lake Oahe, North Dakota, May 1988 through April 1991

USGS Publications Warehouse

Berkas, Wayne R.

1995-01-01

Sediment data were collected on and along the Missouri River downstream from Garrison Dam during May 1988, May 1989, and April 1991 to characterize sediment transport in the river. Specific study objectives were to (1) identify erosional and depositional reaches during two steady-state low-flow periods and one steady-state high-flow period; (2) determine if the reaches are consistently eroding or depositing, regardless of streamflow; and (3) determine the sources of suspended sediment in the river. Erosional and depositional reaches differed between the two low-flow periods, indicating that slight changes in the channel configuration between the two periods caused changes in erosional and depositional patterns. Erosional and depositional reaches also differed between the low-flow periods and the high-flow period, indicating that channel changes and increased streamflow velocities affect erosional and depositional reaches. The significant sources of suspended sediment in the Missouri River are the riverbed and riverbanks. The riverbed contributes to the silt and sand load in the river, and the riverbanks contribute to the clay, silt, and sand load. The contribution from tributaries to the suspendedsediment load in the Missouri River usually is small. Occasionally, during low-flow periods on the Missouri River, the Knife River can contribute significantly to the suspended-sediment load in the Missouri River.

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

NASA Astrophysics Data System (ADS)

Mathers, Kate; Rice, Stephen; Wood, Paul

2016-04-01

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

Effects of Coarse Legacy Sediment on Rivers of the Ozark Plateaus and Implications for Native Mussel Fauna

NASA Astrophysics Data System (ADS)

Erwin, S. O.; Jacobson, R. B.; Eric, A. B.; Jones, J. C.; Anderson, B. W.

2015-12-01

Perturbations to sediment regimes due to anthropogenic activities may have long lasting effects, especially in systems dominated by coarse sediment where travel times are relatively long. Effectively evaluating management alternatives requires understanding the future trajectory of river response at both the river network and reach scales. The Ozark Plateaus physiographic province is a montane region in the interior US composed primarily of Paleozoic sedimentary rock. Historic land-use practices around the turn of the last century accelerated delivery of coarse sediment to river channels. Effects of this legacy sediment persist in two national parks, Ozark National Scenic Riverways, MO and Buffalo National River, AR, and are of special concern for management of native mussel fauna. These species require stable habitat, yet they occupy inherently dynamic environments: alluvial rivers. At the river-network scale, analysis of historical data reveals the signature of sediment waves moving through river networks in the Ozarks. Channel planform alternates between relatively stable, straight reaches, and wider, multithread reaches which have been more dynamic over the past several decades. These alternate planform configurations route and store sediment differently, and translate into different patterns of bed stability at the reach scale, which in turn affects the distribution and availability of habitat for native biota. Geomorphic mapping and hydrodynamic modeling reveal the complex relations between planform (in)stability, flow dynamics, bed mobility, and aquatic habitat in systems responding to increased sediment supply. Reaches that have a more dynamic planform may provide more hydraulic refugia and habitat heterogeneity compared to stable, homogeneous reaches. This research provides new insights that may inform management of sediment and mussel habitat in rivers subject to coarse legacy sediment.

Calculation of in situ acoustic sediment attenuation using off-the-shelf horizontal ADCPs in low concentration settings

USGS Publications Warehouse

Haught, Dan; Venditti, Jeremy G.; Wright, Scott A.

2017-01-01

The use of “off-the-shelf” acoustic Doppler velocity profilers (ADCPs) to estimate suspended sediment concentration and grain-size in rivers requires robust methods to estimate sound attenuation by suspended sediment. Theoretical estimates of sediment attenuation require a priori knowledge of the concentration and grain-size distribution (GSD), making the method impractical to apply in routine monitoring programs. In situ methods use acoustic backscatter profile slope to estimate sediment attenuation, and are a more attractive option. However, the performance of in situ sediment attenuation methods has not been extensively compared to theoretical methods. We used three collocated horizontally mounted ADCPs in the Fraser River at Mission, British Columbia and 298 observations of concentration and GSD along the acoustic beams to calculate theoretical and in situ sediment attenuation. Conversion of acoustic intensity from counts to decibels is influenced by the instrument noise floor, which affects the backscatter profile shape and therefore in situ attenuation. We develop a method that converts counts to decibels to maximize profile length, which is useful in rivers where cross-channel acoustic profile penetration is a fraction of total channel width. Nevertheless, the agreement between theoretical and in situ attenuation is poor at low concentrations because cross-stream gradients in concentration, sediment size or GSD can develop, which affect the backscatter profiles. We establish threshold concentrations below which in situ attenuation is unreliable in Fraser River. Our results call for careful examination of cross-stream changes in suspended sediment characteristics and acoustic profiles across a range of flows before in situ attenuation methods are applied in river monitoring programs.

Dilution of 10Be in detrital quartz by earthquake-induced landslides: Implications for determining denudation rates and potential to provide insights into landslide sediment dynamics

NASA Astrophysics Data System (ADS)

West, A. Joshua; Hetzel, Ralf; Li, Gen; Jin, Zhangdong; Zhang, Fei; Hilton, Robert G.; Densmore, Alexander L.

2014-06-01

The concentration of 10Be in detrital quartz (10Beqtz) from river sediments is now widely used to quantify catchment-wide denudation rates but may also be sensitive to inputs from bedrock landslides that deliver sediment with low 10Beqtz. Major landslide-triggering events can provide large amounts of low-concentration material to rivers in mountain catchments, but changes in river sediment 10Beqtz due to such events have not yet been measured directly. Here we examine the impact of widespread landslides triggered by the 2008 Wenchuan earthquake on 10Beqtz in sediment samples from the Min Jiang river basin, in Sichuan, China. Landslide deposit material associated with the Wenchuan earthquake has consistently lower 10Beqtz than in river sediment prior to the earthquake. River sediment 10Beqtz decreased significantly following the earthquake downstream of areas of high coseismic landslide occurrence (i.e., with greater than ∼0.3% of the upstream catchment area affected by landslides), because of input of the 10Be-depleted landslide material, but showed no systematic changes where landslide occurrence was low. Changes in river sediment 10Beqtz concentration were largest in small first-order catchments but were still significant in large river basins with areas of 104-105 km. Spatial and temporal variability in river sediment 10Beqtz has important implications for inferring representative denudation rates in tectonically active, landslide-dominated environments, even in large basins. Although the dilution of 10Beqtz in river sediment by landslide inputs may complicate interpretation of denudation rates, it also may provide a possible opportunity to track the transport of landslide sediment. The associated uncertainties are large, but in the Wenchuan case, calculations based on 10Be mixing proportions suggest that river sediment fluxes in the 2-3 years following the earthquake increased by a similar order of magnitude in the 0.25-1 mm and the <0.25 mm size fractions, as determined from 10Beqtz mixing calculations and hydrological gauging, respectively. Such information could provide new insight into sediment transfer, with implications for secondary sediment-related hazards and for understanding the removal of mass from mountains.

Basin scale controls on CO2 and CH4 emissions from the Upper Mississippi River

USGS Publications Warehouse

Crawford, John T.; Loken, Luke C.; Stanley, Emily H.; Stets, Edward G.; Dornblaser, Mark M.; Striegl, Robert G.

2016-01-01

The Upper Mississippi River, engineered for river navigation in the 1930s, includes a series of low-head dams and navigation pools receiving elevated sediment and nutrient loads from the mostly agricultural basin. Using high-resolution, spatially resolved water quality sensor measurements along 1385 river kilometers, we show that primary productivity and organic matter accumulation affect river carbon dioxide and methane emissions to the atmosphere. Phytoplankton drive CO2to near or below atmospheric equilibrium during the growing season, while anaerobic carbon oxidation supports a large proportion of the CO2 and CH4 production. Reductions of suspended sediment load, absent of dramatic reductions in nutrients, will likely further reduce net CO2emissions from the river. Large river pools, like Lake Pepin, which removes the majority of upstream sediments, and large agricultural tributaries downstream that deliver significant quantities of sediments and nutrients, are likely to persist as major geographical drivers of greenhouse gas emissions.

Sediment-quality assessment of the Lower Oconee River

USGS Publications Warehouse

Lasier, P.J.; Winger, P.V.; Shelton, J.L.; Bogenrieder, K.J.

2004-01-01

Sediment quality was assessed at multiple sites in the lower Oconee River, GA to identify contaminants potentially affecting the survival of an endemic ?At-Risk? species of fish, the robust redhorse (Moxostoma robustum). Five major tributaries that drain urban and agricultural watersheds enter this stretch of river and several carry permitted municipal and industrial effluents containing Cd, Cu, and Zn. Sediments for chemical analyses and toxicity tests with Hyalella azteca (Amphipoda) were collected at 12 locations that included sites above and below the major tributaries. Compared to national data bases and to the nearby Apalachicola-Chattahoochee-Flint watershed, sediments from the Oconee River had elevated concentrations of Cr, Cu, Hg and Zn. Zinc concentrations showed a marked increase in sediment downstream of the confluence of Buffalo Creek demonstrating contributions from permitted municipal and industrial effluents discharged to that tributary. When exposed to these sediments, growth of H. azteca was significantly reduced. Amphipod growth was also reduced when exposed to sediments collected from another site due to toxicity from Cr. Sediments in the lower Oconee River appear to be impaired due to metal contamination and could pose a threat to organisms, such as the robust redhorse, that are closely associated with this matrix during their life cycle.

How important and different are tropical rivers? - An overview

NASA Astrophysics Data System (ADS)

Syvitski, James P. M.; Cohen, Sagy; Kettner, Albert J.; Brakenridge, G. Robert

2014-12-01

Tropical river systems, wherein much of the drainage basin experiences tropical climate are strongly influenced by the annual and inter-annual variations of the Inter-tropical Convergence Zone (ITCZ) and its derivative monsoonal winds. Rivers draining rainforests and those subjected to tropical monsoons typically demonstrate high runoff, but with notable exceptions. High rainfall intensities from burst weather events are common in the tropics. The release of rain-forming aerosols also appears to uniquely increase regional rainfall, but its geomorphic manifestation is hard to detect. Compared to other more temperate river systems, climate-driven tropical rivers do not appear to transport a disproportionate amount of particulate load to the world's oceans, and their warmer, less viscous waters are less competent. Tropical biogeochemical environments do appear to influence the sedimentary environment. Multiple-year hydrographs reveal that seasonality is a dominant feature of most tropical rivers, but the rivers of Papua New Guinea are somewhat unique being less seasonally modulated. Modeled riverine suspended sediment flux through global catchments is used in conjunction with observational data for 35 tropical basins to highlight key basin scaling relationships. A 50 year, daily model simulation illuminates how precipitation, relief, lithology and drainage basin area affect sediment load, yield and concentration. Local sediment yield within the Amazon is highest near the Andes, but decreases towards the ocean as the river's discharge is diluted by water influxes from sediment-deprived rainforest tributaries. Bedload is strongly affected by the hydraulic gradient and discharge, and the interplay of these two parameters predicts foci of net bedload deposition or erosion. Rivers of the tropics have comparatively low inter-annual variation in sediment yield.

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

Treesearch

A.C. Guy; T.M. DeSutter; F.X.M. Casey; R. Kolka; H. Hakk

2012-01-01

Spring flooding of the Red River of the North (RR) is common, but little information exits on how these flood events affect water and overbank sediment quality within an urban area. With the threat of the spring 2009 flood in the RR predicted to be the largest in recorded history and the concerns about the flooding of farmsteads, outbuildings, garages, and basements,...

Chlorinated and polycyclic aromatic hydrocarbons in riverine and estuarine sediments from Pearl River Delta, China.

PubMed

Mai, Bi-Xian; Fu, Jia-Mo; Sheng, Guo-Ying; Kang, Yue-Hui; Lin, Zheng; Zhang, Gan; Min, Yu-Shuan; Zeng, Eddy Y

2002-01-01

Spatial distribution of chlorinated hydrocarbons [chlorinated pesticides (CPs) and polychlorinated biphenyls (PCBs)] and polycyclic aromatic hydrocarbons (PAHs) was measured in riverine and estuarine sediment samples from Pearl River Delta, China, collected in 1997. Concentrations of CPs of the riverine sediment samples range from 12 to 158 ng/g, dry weight, while those of PCBs range from 11 to 486 ng/g. The CPs concentrations of the estuarine sediment samples are in the range 6-1658 ng/g, while concentrations of PCBs are in the range 10-339 ng/g. Total PAH concentration ranges from 1168 to 21,329 ng/g in the riverine sediment samples, whereas the PAH concentration ranges from 323 to 14,812 ng/g in the sediment samples of the Estuary. Sediment samples of the Zhujiang River and Macao harbor around the Estuary show the highest concentrations of CPs, PCBs, and PAHs. Possible factors affecting the distribution patterns are also discussed based on the usage history of the chemicals, hydrologic condition, and land erosion due to urbanization processes. The composition of PAHs is investigated and used to assess petrogenic, combustion and naturally derived PAHs of the sediment samples of the Pearl River Delta. In addition, the concentrations of a number of organic compounds of the Pearl River Delta samples indicate that sediments of the Zhujiang river and Macao harbor are most likely to pose biological impairment.

Tracking riverborne sediment and contaminants in Commencement Bay, Washington, using geochemical signatures

USGS Publications Warehouse

Takesue, Renee K.; Conn, Kathleen E.; Dinicola, Richard S.

2017-09-29

Large rivers carry terrestrial sediment, contaminants, and other materials to the coastal zone where they can affect marine biogeochemical cycles and ecosystems. This U.S. Geological Survey study combined river and marine sediment geochemistry and organic contaminant analyses to identify riverborne sediment and associated contaminants at shoreline sites in Commencement Bay, Puget Sound, Washington, that could be used by adult forage fish and other marine organisms. Geochemical signatures distinguished the fine fraction (<0.063 millimeter, mm) of Puyallup River sediment—which originates from Mount Rainier, a Cascade volcano—from glacial fine sediment in lowland bluffs that supply sediment to beaches. In combination with activities of beryllium-7 (7Be), a short-lived radionuclide, geochemical signatures showed that winter 2013–14 sediment runoff from the Puyallup River was transported to and deposited along the north shore of Commencement Bay, then mixed downward into the sediment column. The three Commencement Bay sites at which organic contaminants were measured in surface sediment did not have measurable 7Be activities in that layer, so their contaminant assemblages were attributed to sources from previous years. Concentrations of organic contaminants (the most common of which were polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and fecal sterols) were higher in the <0.063-mm fraction compared to the <2-mm fraction, in winter compared to summer, in river suspended sediment compared to river bar and bank sediment, and in marine sediment compared to river sediment. The geochemical property barium/aluminum (Ba/Al) showed that the median percentage of Puyallup River derived fine surface sediment along the shoreline of Commencement Bay was 77 percent. This finding, in combination with higher concentrations of organic contaminants in marine rather than river sediment, indicates that riverborne sediment-bound contaminants are retained in shallow marine habitats of Commencement Bay. The retention of earlier inputs complicates efforts to identify recent inputs and sources. Understanding modern sources and fates of riverborne sediment and contaminants and their potential ecological impacts will therefore require a suite of targeted geochemical studies in such marine depositional environments.

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

NASA Astrophysics Data System (ADS)

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

2014-12-01

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

U isotopes distribution in the Lower Rhone River and its implication on radionuclides disequilibrium within the decay series.

PubMed

Zebracki, Mathilde; Cagnat, Xavier; Gairoard, Stéphanie; Cariou, Nicolas; Eyrolle-Boyer, Frédérique; Boulet, Béatrice; Antonelli, Christelle

2017-11-01

The large rivers are main pathways for the delivery of suspended sediments into coastal environments, affecting the biogeochemical fluxes and the ecosystem functioning. The radionuclides from 238 U and 232 Th-series can be used to understand the dynamic processes affecting both catchment soil erosion and sediment delivery to oceans. Based on annual water discharge the Rhone River represents the largest river of the Mediterranean Sea. The Rhone valley also represents the largest concentration in nuclear power plants in Europe. A radioactive disequilibrium between particulate 226 Ra (p) and 238 U (p) was observed in the suspended sediment discharged by the Lower Rhone River (Eyrolle et al. 2012), and a fraction of particulate 234 Th was shown to derive from dissolved 238 U (d) (Zebracki et al. 2013). This extensive study has investigated the dissolved U isotopes distribution in the Lower Rhone River and its implication on particulate radionuclides disequilibrium within the decay series. The suspended sediment and filtered river waters were collected at low and high water discharges. During the 4-months of the study, two flood events generated by the Rhone southern tributaries were monitored. In river waters, the total U (d) concentration and U isotopes distribution were obtained through Q-ICP-MS measurements. The Lower Rhone River has displayed non-conservative U-behavior, and the variations in U (d) concentration between southern tributaries were related to the differences in bedrock lithology. The artificially occurring 236 U was detected in the Rhone River at low water discharges, and was attributed to the liquid releases from nuclear industries located along the river. The ( 235 U/ 238 U) (d) activity ratio (=AR) in river waters was representative of the 235 U natural abundance on Earth. The ( 226 Ra/ 238 U) (p) AR in suspended sediment has indicated a radioactive disequilibrium (average 1.3 ± 0.1). The excess of 234 Th in suspended sediment =( 234 Th xs(p) ) was apparent solely at low water discharges. The activity of 234 Th xs(p) was calculated through gamma measurements and ranged from unquantifiable to 56 ± 14 Bq kg -1 . The possibility of using 234 Th as a tracer for the suspended sediment dynamics in large Mediterranean river was then discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Metagenomic Insights into Effects of Chemical Pollutants on Microbial Community Composition and Function in Estuarine Sediments Receiving Polluted River Water.

PubMed

Lu, Xiao-Ming; Chen, Chang; Zheng, Tian-Ling

2017-05-01

Pyrosequencing and metagenomic profiling were used to assess the phylogenetic and functional characteristics of microbial communities residing in sediments collected from the estuaries of Rivers Oujiang (OS) and Jiaojiang (JS) in the western region of the East China Sea. Another sediment sample was obtained from near the shore far from estuaries, used for contrast (CS). Characterization of estuary sediment bacterial communities showed that toxic chemicals potentially reduced the natural variability in microbial communities, while they increased the microbial metabolic enzymes and pathways. Polycyclic aromatic hydrocarbons (PAHs) and nitrobenzene were negatively correlated with the bacterial community variation. The dominant class in the sediments was Gammaproteobacteria. According to Kyoto Encyclopedia of Genes and Genomes (KEGG) enzyme profiles, dominant enzymes were found in estuarine sediments, which increased greatly, such as 2-oxoglutarate synthase, acetolactate synthase, inorganic diphosphatase, and aconitate hydratase. In KEGG pathway profiles, most of the pathways were also dominated by specific metabolism in these sediments and showed a marked increase, for instance alanine, aspartate, and glutamate metabolism, carbon fixation pathways in prokaryotes, and aminoacyl-tRNA biosynthesis. The estuarine sediment bacterial diversity varied with the polluted river water inputs. In the estuary receiving river water from the more seriously polluted River Oujiang, the sediment bacterial community function was more severely affected.

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

PubMed

Vosoogh, Ali; Saeedi, Mohsen; Lak, Raziyeh

2016-11-01

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

Effect of high sedimentation rates on surface sediment dynamics and mangrove growth in the Porong River, Indonesia.

PubMed

Sidik, Frida; Neil, David; Lovelock, Catherine E

2016-06-15

Large quantities of mud from the LUSI (Lumpur Sidoarjo) volcano in northeastern Java have been channeled to the sea causing high rates of sediment delivery to the mouth of the Porong River, which has a cover of natural and planted mangroves. This study investigated how the high rates of sediment delivery affected vertical accretion, surface elevation change and the growth of Avicennia sp., the dominant mangrove species in the region. During our observations in 2010-2011 (4-5years after the initial volcanic eruption), very high rates of sedimentation in the forests at the mouth of the river gave rise to high vertical accretion of over 10cmy(-1). The high sedimentation rates not only resulted in reduced growth of Avicennia sp. mangrove trees at the two study sites at the Porong River mouth, but also gave rise to high soil surface elevation gains. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantification of annual sediment deposits for sustainable sand management in Aghanashini river estuary.

PubMed

Ramachandra, T V; Vinay, S; Subash Chandran, M D

2018-01-15

Sedimentation involving the process of silt transport also carries nutrients from upstream to downstream of a river/stream. Sand being one of the important fraction of these sediments is extracted in order to cater infrastructural/housing needs in the region. This communication is based on field research in the Aghanshini river basin, west coast of India. Silt yield in the river basin and the sedimentation rate assessed using empirical techniques supplemented with field quantifications using soundings (SONAR), show the sediment yield of 1105-1367 kilo cum per year and deposition of sediment of 61 (2016) to 71 (2015) cm. Quantifications of extractions at five locations, reveal of over exploitation of sand to an extent of 30% with damages to the breeding ground of fishes, reduced productivity of bivalves, etc., which has affected dependent people's livelihood. This study provides vital insights towards sustainable sand harvesting through stringent management practices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Trends in the sediment yield of the Sacramento River, California, 1957-2001

USGS Publications Warehouse

Wright, Scott A.; Schoellhamer, David H.

2004-01-01

Human activities within a watershed, such as agriculture, urbanization, and dam building, may affect the sediment yield from the watershed. Because the equilibrium geomorphic form of an estuary is dependent in part on the sediment supply from the watershed, anthropogenic activities within the watershed have the potential to affect estuary geomorphology. The Sacramento River drains the northern half of California’s Central Valley and is the primary source of sediment to San Francisco Bay. In this paper, it is shown that the delivery of suspended-sediment from the Sacramento River to San Francisco Bay has decreased by about one-half during the period 1957 to 2001. Many factors may be contributing to the trend in sediment yield, including the depletion of erodible sediment from hydraulic mining in the late 1800s, trapping of sediment in reservoirs, riverbank protection, altered land-uses (such as agriculture, grazing, urbanization, and logging), and levees. This finding has implications for planned tidal wetland restoration activities around San Francisco Bay, where an adequate sediment supply will be needed to build subsided areas to elevations typical of tidal wetlands as well as to keep pace with projected sea-level rise. In a broader context, the study underscores the need to address anthropogenic impacts on watershed sediment yield when considering actions such as restoration within downstream depositional areas.

Conceptual model of sedimentation in the Sacramento-San Joaquin River Delta

USGS Publications Warehouse

Schoellhamer, David H.; Wright, Scott A.; Drexler, Judith Z.

2012-01-01

Sedimentation in the Sacramento–San Joaquin River Delta builds the Delta landscape, creates benthic and pelagic habitat, and transports sediment-associated contaminants. Here we present a conceptual model of sedimentation that includes submodels for river supply from the watershed to the Delta, regional transport within the Delta and seaward exchange, and local sedimentation in open water and marsh habitats. The model demonstrates feedback loops that affect the Delta ecosystem. Submerged and emergent marsh vegetation act as ecosystem engineers that can create a positive feedback loop by decreasing suspended sediment, increasing water column light, which in turn enables more vegetation. Sea-level rise in open water is partially countered by a negative feedback loop that increases deposition if there is a net decrease in hydrodynamic energy. Manipulation of regional sediment transport is probably the most feasible method to control suspended sediment and thus turbidity. The conceptual model is used to identify information gaps that need to be filled to develop an accurate sediment transport model.

Global scale modeling of riverine sediment loads: tropical rivers in a global context

NASA Astrophysics Data System (ADS)

Cohen, Sagy; Syvitski, James; Kettner, Albert

2015-04-01

A global scale riverine sediment flux model (termed WBMsed) is introduced. The model predicts spatially and temporally explicit water, suspended sediment and nutrients flux in relatively high resolutions (6 arc-min and daily). Modeled riverine suspended sediment flux through global catchments is used in conjunction with observational data for 35 tropical basins to highlight key basin scaling relationships. A 50 year, daily model simulation illuminates how precipitation, relief, lithology and drainage basin area affect sediment load, yield and concentration. Tropical river systems, wherein much of a drainage basin experiences tropical climate are strongly influenced by the annual and inter-annual variations of the Inter-tropical Convergence Zone (ITCZ) and its derivative monsoonal winds, have comparatively low inter-annual variation in sediment yield. Rivers draining rainforests and those subjected to tropical monsoons typically demonstrate high runoff, but with notable exceptions. High rainfall intensities from burst weather events are common in the tropics. The release of rain-forming aerosols also appears to uniquely increase regional rainfall, but its geomorphic manifestation is hard to detect. Compared to other more temperate river systems, climate-driven tropical rivers do not appear to transport a disproportionate amount of particulate load to the world's oceans, and their warmer, less viscous waters are less competent. Multiple-year hydrographs reveal that seasonality is a dominant feature of most tropical rivers, but the rivers of Papua New Guinea are somewhat unique being less seasonally modulated. Local sediment yield within the Amazon is highest near the Andes, but decreases towards the ocean as the river's discharge is diluted by water influxes from sediment-deprived rainforest tributaries

Geochemical data for core and bottom-sediment samples collected in 2007 from Grand Lake O' the Cherokees, northeast Oklahoma

USGS Publications Warehouse

Fey, David L.; Becker, Mark F.; Smith, Kathleen S.

2010-01-01

Grand Lake O' the Cherokees is a large reservoir in northeast Oklahoma, below the confluence of the Neosho and Spring Rivers, both of which drain the Tri-State Mining District to the north. The Tri-State district covers an area of 1,200 mi2 (3,100 km2) and comprises Mississippi Valley-type lead-zinc deposits. A result of 120 years of mining activity is an estimated 75 million tons of processed mine tailings (chat) remaining in the district. Concerns of sediment quality and the possibility of human exposure to cadmium and lead through eating fish have led to several studies of the sediments in the Tri-State district. In order to record the transport and deposition of metals from the Tri-State district by the Spring and Neosho Rivers into Grand Lake O' the Cherokees, the U.S. Geological Survey collected 11 sediment cores and 15 bottom-sediment samples in September 2007. Subsamples from five selected cores and the bottom-sediment samples were analyzed for major and trace elements and forms of carbon. The sediment samples collected from the sediment-water interface had larger average concentrations of zinc, cadmium, and lead than local background. The core collected from the Spring River had the largest concentrations of mining-related elements. A core collected just south of Twin Bridges State Park, at the confluence of the Spring and Neosho Rivers, showed a mixing zone with more mining-related elements coming from the Spring River side. The element zinc showed the most definitive patterns in graphs depicting concentration-versus-depth profiles. A core collected from the main body of the reservoir showed affected sediment down to a depth of 85 cm (33 in). This core and two others appear to have penetrated to below mining-affected sediment.

Anthropogenic influence on sedimentation and intertidal mudflat change in San Pablo Bay, California: 1856-1983

USGS Publications Warehouse

Jaffe, B.E.; Smith, R.E.; Foxgrover, A.C.

2007-01-01

Analysis of a series of historical bathymetric surveys has revealed large changes in morphology and sedimentation from 1856 to 1983 in San Pablo Bay, California. In 1856, the morphology of the bay was complex, with a broad main channel, a major side channel connecting to the Petaluma River, and an ebb-tidal delta crossing shallow parts of the bay. In 1983, its morphology was simpler because all channels except the main channel had filled with sediment and erosion had planed the shallows creating a uniform gently sloping surface. The timing and patterns of geomorphic change and deposition and erosion of sediment were influenced by human activities that altered sediment delivery from rivers. From 1856 to 1887, high sediment delivery (14.1 ?? 106 m3/yr) to San Francisco Bay during the hydraulic gold-mining period in the Sierra Nevada resulted in net deposition of 259 ?? 14 ?? 106 m3 in San Pablo Bay. This rapid deposition filled channels and increased intertidal mudflat area by 60% (37.4 ?? 3.4 to 60.6 ?? 6.2 km2). From 1951 to 1983, 23 ?? 3 ?? 106 m3 of sediment was eroded from San Pablo Bay as sediment delivery from the Sacramento and San Joaquin Rivers decreased to 2.8 ?? 106 m3/yr because of damming of rivers, riverbank protection, and altered land use. Intertidal mudflat area in 1983 was 31.8 ?? 3.9 km2, similar to that in 1856. Intertidal mudflat distribution in 1983, however, was fairly uniform whereas most of the intertidal mudflats were in the western part of San Pablo Bay in 1856. Sediment delivery, through its affect on shallow parts of the bay, was determined to be a primary control on intertidal mudflat area. San Pablo Bay has been greatly affected by human activities and will likely continue to erode in the near term in response to a diminished sediment delivery from rivers. ?? 2007 Elsevier Ltd. All rights reserved.

Measuring Density Stratification and Understanding its Impact on Sediment Transport in Fine-grained Rivers, Based on Observations from the Lower Yellow River, China

NASA Astrophysics Data System (ADS)

Moodie, A. J.; Nittrouer, J. A.; Ma, H.; Lamb, M. P.; Carlson, B.; Kineke, G. C.; Parker, G.

2017-12-01

High concentrations of suspended sediment in channelized fluid flow produces density stratification that can alter the turbulent flow structure, thus limiting fluid momentum redistribution and affecting sediment transport capacity. A low channel-bed slope and large flow depth are hypothesized to be additional important factors contributing to density stratification. However, there are limited observations of density stratification in large rivers, especially those that carry significant fluxes of mud, and so the conditions leading to the development of density stratification are poorly constrained. The Yellow River, China, is a fine-grained and low-sloping river that maintains some of the highest suspended sediment concentrations in large rivers worldwide, making it an ideal natural laboratory for studying density stratification and its impact on sediment transport. Suspended sediment samples from the lower Yellow River, collected over a range of discharge conditions, produced sediment concentration profiles that are used in conjunction with velocity profiles to determine the threshold shear velocity for density stratification effects to develop. Comparing measured and predicted concentration and velocity profiles demonstrates that, there is no significant density stratification for base flow conditions; however, above a shear velocity value of 0.05 m/s, there is a progressive offset between the measured and predicted profiles, indicating that density stratification is increasingly important with higher shear stress values. The analyses further indicate that sediment entrainment from the bed and sediment diffusivity within the water column are significantly impacted by density stratification, suggesting that shear stress and sediment transport rates are inhibited by the development of density stratification. Near-bed concentration measurements are used to assess a stress-to-entrainment relationship, accounting for density stratification. These measurements are being used to refine relations for sediment entrainment and sediment flux in sandy and muddy, lowland rivers and deltas.

Source, conveyance and fate of suspended sediments following Hurricane Irene. New England, USA

USGS Publications Warehouse

Yellen, Brian; Woodruff, Jon D.; Kratz, Laura N.; Mabee, Steven B.; Morrison, Jonathan; Martini, Anna M.

2014-01-01

Hurricane Irene passed directly over the Connecticut River valley in late August, 2011. Intense precipitation and high antecedent soil moisture resulted in record flooding, mass wasting and fluvial erosion, allowing for observations of how these rare but significant extreme events affect a landscape still responding to Pleistocene glaciation and associated sediment emplacement. Clays and silts from upland glacial deposits, once suspended in the stream network, were routed directly to the mouth of the Connecticut River, resulting in record-breaking sediment loads fifteen-times greater than predicted from the pre-existing rating curve. Denudation was particularly extensive in mountainous areas. We calculate that sediment yield during the event from the Deerfield River, a steep tributary comprising 5% of the entire Connecticut River watershed, exceeded at minimum 10–40 years of routine sediment discharge and accounted for approximately 40% of the total event sediment discharge from the Connecticut River. A series of surface sediment cores taken in floodplain ponds adjacent to the tidal section of the Connecticut River before and after the event provides insight into differences in sediment sourcing and routing for the Irene event compared to periods of more routine flooding. Relative to routine conditions, sedimentation from Irene was anomalously inorganic, fine grained, and enriched in elements commonly found in chemically immature glacial tills and glaciolacustrine material. These unique sedimentary characteristics document the crucial role played by extreme precipitation from tropical disturbances in denuding this landscape.

Source, conveyance and fate of suspended sediments following Hurricane Irene. New England, USA

NASA Astrophysics Data System (ADS)

Yellen, B.; Woodruff, J. D.; Kratz, L. N.; Mabee, S. B.; Morrison, J.; Martini, A. M.

2014-12-01

Hurricane Irene passed directly over the Connecticut River valley in late August, 2011. Intense precipitation and high antecedent soil moisture resulted in record flooding, mass wasting and fluvial erosion, allowing for observations of how these rare but significant extreme events affect a landscape still responding to Pleistocene glaciation and associated sediment emplacement. Clays and silts from upland glacial deposits, once suspended in the stream network, were routed directly to the mouth of the Connecticut River, resulting in record-breaking sediment loads fifteen-times greater than predicted from the pre-existing rating curve. Denudation was particularly extensive in mountainous areas. We calculate that sediment yield during the event from the Deerfield River, a steep tributary comprising 5% of the entire Connecticut River watershed, exceeded at minimum 10-40 years of routine sediment discharge and accounted for approximately 40% of the total event sediment discharge from the Connecticut River. A series of surface sediment cores taken in floodplain ponds adjacent to the tidal section of the Connecticut River before and after the event provides insight into differences in sediment sourcing and routing for the Irene event compared to periods of more routine flooding. Relative to routine conditions, sedimentation from Irene was anomalously inorganic, fine grained, and enriched in elements commonly found in chemically immature glacial tills and glaciolacustrine material. These unique sedimentary characteristics document the crucial role played by extreme precipitation from tropical disturbances in denuding this landscape.

The influence of the scale of mining activity and mine site remediation on the contamination legacy of historical metal mining activity.

PubMed

Bird, Graham

2016-12-01

Globally, thousands of kilometres of rivers are degraded due to the presence of elevated concentrations of potentially harmful elements (PHEs) sourced from historical metal mining activity. In many countries, the presence of contaminated water and river sediment creates a legal requirement to address such problems. Remediation of mining-associated point sources has often been focused upon improving river water quality; however, this study evaluates the contaminant legacy present within river sediments and attempts to assess the influence of the scale of mining activity and post-mining remediation upon the magnitude of PHE contamination found within contemporary river sediments. Data collected from four exemplar catchments indicates a strong relationship between the scale of historical mining, as measured by ore output, and maximum PHE enrichment factors, calculated versus environmental quality guidelines. The use of channel slope as a proxy measure for the degree of channel-floodplain coupling indicates that enrichment factors for PHEs in contemporary river sediments may also be the highest where channel-floodplain coupling is the greatest. Calculation of a metric score for mine remediation activity indicates no clear influence of the scale of remediation activity and PHE enrichment factors for river sediments. It is suggested that whilst exemplars of significant successes at improving post-remediation river water quality can be identified; river sediment quality is a much more long-lasting environmental problem. In addition, it is suggested that improvements to river sediment quality do not occur quickly or easily as a result of remediation actions focused a specific mining point sources. Data indicate that PHEs continue to be episodically dispersed through river catchments hundreds of years after the cessation of mining activity, especially during flood flows. The high PHE loads of flood sediments in mining-affected river catchments and the predicted changes to flood frequency, especially, in many river catchments, provides further evidence of the need to enact effective mine remediation strategies and to fully consider the role of river sediments in prolonging the environmental legacy of historical mine sites.

Characterization of hydrodynamic and sediment conditions in the lower Yampa River at Deerlodge Park, east entrance to Dinosaur National Monument, northwest Colorado, 2011

USGS Publications Warehouse

Williams, Cory A.

2013-01-01

The Yampa River in northwestern Colorado is the largest, relatively unregulated river system in the upper Colorado River Basin. Water from the Yampa River Basin continues to be sought for a number of municipal, industrial, and energy uses. It is anticipated that future water development within the Yampa River Basin above the amount of water development identified under the Upper Colorado River Endangered Fish Recovery Implementation Program and the Programmatic Biological Opinion may require additional analysis in order to understand the effects on habitat and river function. Water development in the Yampa River Basin could alter the streamflow regime and, consequently, could lead to changes in the transport and storage of sediment in the Yampa River at Deerlodge Park. These changes could affect the physical form of the reach and may impact aquatic and riparian habitat in and downstream from Deerlodge Park. The U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, began a study in 2011 to characterize the current hydrodynamic and sediment-transport conditions for a 2-kilometer reach of the Yampa River in Deerlodge Park. Characterization of channel conditions in the Deerlodge Park reach was completed through topographic surveying, grain-size analysis of streambed sediment, and characterization of streamflow properties. This characterization provides (1) a basis for comparisons of current stream functions (channel geometry, sediment transport, and stream hydraulics) to future conditions and (2) a dataset that can be used to assess channel response to streamflow alteration scenarios indicated from computer modeling of streamflow and sediment-transport conditions.

Assessment of chemical and biological significance of arsenical species in the Maurice River drainage basin (N. J. ). Part I. Distribution in water and river and lake sediments

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

Faust, S.D.; Winka, A.J.; Belton, T.

1987-01-01

Levels of arsenic were determined in the bottom sediments and waters of the Maurice River, Blackwater Branch, and Union Lake, (N.J.) that were contaminated by a local chemical industry. This was the only known source of the arsenic. Levels of total arsenic in the sediments and waters were determined quarterly over the course of one year. Sediments were extracted for water soluble and total extractable arsenic fractions and partitioned into four species: monomethylarsonic acid (MMAA), dimethylarsinic acid (DMAA), arsenite (As(III)), and arsenate (As(V)). In Union Lake at a shallow sandy sediment site, As (V) predominates. In organic sediments, As (III)more » or (V) predominate depending upon the dissolved oxygen content of the overlying waters. The oxidations state of the arsenic was affected also by the seasonal lake cycles of stratifying or mixing.« less

Changes in the areal extents of the Athabasca River, Birch River, and Cree Creek Deltas, 1950-2014, Peace-Athabasca Delta, Canada

NASA Astrophysics Data System (ADS)

Timoney, Kevin; Lee, Peter

2016-04-01

Deltas form where riverborne sediment accumulates at the interface of river mouths and their receiving water bodies. Their areal extent is determined by the net effect of processes that increase their extent, such as sediment accumulation, and processes that decrease their extent, such as erosion and subsidence. Through sequential mapping and construction of river discharge and sediment histories, this study examined changes in the subaerial extents of the Cree Creek and Athabasca River Deltas (both on the Athabasca River system) and the Birch River Delta in northern Canada over the period 1950-2014. The purpose of the study was to determine how, when, and why the deltas changed in areal extent. Temporal growth patterns were similar across the Athabasca and Birch River systems indicative of a climatic signal. Little or no areal growth occurred from 1950 to 1968; moderate growth occurred between 1968 and the early to mid-1980s; and rapid growth occurred between 1992 and 2012. Factors that affected delta progradation included dredging, sediment supply, isostatic drowning, delta front bathymetry, sediment capture efficiency, and storms. In relation to sediment delivered, areal growth rates were lowest in the Athabasca Delta, intermediate in the Birch Delta, and highest in the Cree Creek Delta. Annual sediment delivery is increasing in the Cree Creek Delta; there were no significant trends in annual sediment delivery in the Birch and Athabasca Deltas. There was a lag of up to several years between sediment delivery events and progradation. Periods of delta progradation were associated with low water levels of the receiving basins. Predicted climate-change driven declines in river discharge and lake levels may accelerate delta progradation in the region. In the changing ecosystems of northeastern Alberta, inadequate monitoring of vegetation, landforms, and sediment regimes hampers the elucidation of the nature, rate, and causality of ecosystem changes.

River Flow Impacts Bacterial and Archaeal Community Structure in Surface Sediments in the Northern Gulf of Mexico.

PubMed

Ortmann, Alice C; Brannock, Pamela M; Wang, Lei; Halanych, Kenneth M

2018-04-17

Meiobenthic community structure in the northern Gulf of Mexico has been shown to be driven by geographical differences due to inshore-offshore gradients and location relative to river discharge. Samples collected along three transects spanning Mobile Bay, Alabama, showed significant differences in meiobenthic communities east of the bay compared to those sampled from the west. In contrast, analysis of bacterial and archaeal communities from the same sediment samples shows that the inshore-offshore gradient has minimal impact on their community structure. Significant differences in community structure were observed for Bacteria and Archaea between the east and west samples, but there was no difference in richness or diversity. Grouped by sediment type, higher richness was observed in silty samples compared to sandy samples. Significant differences were also observed among sediment types for community structure with bacteria communities in silty samples having more anaerobic sulfate reducers compared to aerobic heterotrophs, which had higher abundances in sandy sediments. This is likely due to increased organic matter in the silty sediments from the overlying river leading to low oxygen habitats. Most archaeal sequences represented poorly characterized high-level taxa, limiting interpretation of their distributions. Overlap between groups based on transect and sediment characteristics made determining which factor is more important in structuring bacterial and archaeal communities difficult. However, both factors are driven by discharge from the Mobile River. Although inshore-offshore gradients do not affect Bacteria or Archaea to the same extent as the meiobenthic communities, all three groups are strongly affected by sediment characteristics.

Continuous measurement of suspended-sediment discharge in rivers by use of optical backscatterance sensors

USGS Publications Warehouse

Schoellhamer, D.H.; Wright, S.A.; Bogen, J.; Fergus, T.; Walling, D.

2003-01-01

Optical sensors have been used to measure turbidity and suspended-sediment concentration by many marine and estuarine studies, and optical sensors can provide automated, continuous time series of suspended-sediment concentration and discharge in rivers. Three potential problems with using optical sensors are biological fouling, particle-size variability, and particle-reflectivity variability. Despite varying particle size, output from an optical backscatterance sensor in the Sacramento River at Freeport, California, USA, was calibrated successfully to discharge-weighted, cross-sectionally averaged suspended-sediment concentration, which was measured with the equal discharge-, or width-increment, methods and an isokinetic sampler. A correction for sensor drift was applied to the 3-year time series. However, the calibration of an optical backscatterance sensor used in the Colorado River at Cisco, Utah, USA, was affected by particle-size variability. The adjusted time series at Freeport was used to calculate hourly suspended-sediment discharge that compared well with daily values from a sediment station at Freeport. The appropriateness of using optical sensors in rivers should be evaluated on a site-specific basis and measurement objectives, potential particle size effects, and potential fouling should be considered.

Flow Field Analysis of Fish Farm and Planting Area in Floodplain during Flood

NASA Astrophysics Data System (ADS)

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

2017-12-01

Fish farms constructing and crops planting is common in floodplain in Taiwan. The physiographic soil erosion-deposition (PSED) model was applied to simulate the sediment yield, the runoff, and sediment transport rate of the river watershed corresponding to one-day rainstorms of the return periods of 25, 50, and 100 year. The variation of flow field in the river sections could be simulated by utilizing the alluvial river-movable bed two dimensional (ARMB-2D) model. The results reveal that the tendency of river discharge, sediment deposition and erosion obtained from these two models is agreeable by calibration and verification. The water flow affected by fish farms and planting areas in floodplain during flood was analyzed. Lastly, based on the simulation results obtained from the PESD and ARMB-2D models for one-day rainstorms of the return periods of 25, 50, and 100 year, the illegal fish farms and planting area with severe variations of river flow and affected he capability for flood conveyance will be referred to as the demolishing-to-be areas. We could also suggest the management strategy of application for fish farms constructing and crops planting in river areas by incorporating the ability of our model to provide information of river flow to enhance the flood conveyance.

Erosion properties of cohesive sediments in the Colorado River in Grand Canyon

USGS Publications Warehouse

Akahori, R.; Schmeeckle, M.W.; Topping, D.J.; Melis, T.S.

2008-01-01

Cohesive sediment deposits characterized by a high fraction of mud (silt plus clay) significantly affect the morphology and ecosystem of rivers. Potentially cohesive sediment samples were collected from deposits in the Colorado River in Marble and Grand Canyons. The erosion velocities of these samples were measured in a laboratory flume under varying boundary shear stresses. The non-dimensional boundary shear stress at which erosion commenced showed a systematic deviation from that of non-cohesive sediments at mud fractions greater than 0.2. An empirical relation for the boundary shear stress threshold of erosion as a function of mud fraction was proposed. The mass erosion rate was modelled using the Ariathurai-Partheniades equation. The erosion rate parameter of this equation was found to be a strong function of mud fraction. Under similar boundary shear stress and sediment supply conditions in the Colorado River, cohesive lateral eddy deposits formed of mud fractions in excess of 0.2 will erode less rapidly than non-cohesive deposits. Copyright ?? 2008 John Wiley & Sons, Ltd.

Preliminary Experimental Results on the Technique of Artificial River Replenishment to Mitigate Sediment Loss Downstream Dams

NASA Astrophysics Data System (ADS)

Franca, M. J.; Battisacco, E.; Schleiss, A. J.

2014-12-01

The transport of sediments by water throughout the river basins, from the steep slopes of the upstream regions to the sea level, is recognizable important to keep the natural conditions of rivers with a role on their ecology processes. Over the last decades, a reduction on the supply of sand and gravel has been observed downstream dams existing in several alpine rivers. Many studies highlight that the presence of a dam strongly modifies the river behavior in the downstream reach, in terms of morphology and hydrodynamics, with consequences on local ecology. Sediment deficit, bed armoring, river incision and bank instability are the main effects which affect negatively the aquatic habitats and the water quality. One of the proposed techniques to solve the problem of sediment deficit downstream dams, already adopted in few Japanese and German rivers although on an unsatisfactory fashion, is the artificial replenishment of these. Generally, it was verified that the erosion of the replenishments was not satisfactory and the transport rate was not enough to move the sediments to sufficient downstream distances. In order to improve and to provide an engineering answer to make this technique more applicable, a series of laboratory tests are ran as preparatory study to understand the hydrodynamics of the river flow when the replenishment technique is applied. Erodible volumes, with different lengths and submergence conditions, reproducing sediment replenishments volumes, are positioned along a channel bank. Different geometrical combinations of erodible sediment volumes are tested as well on the experimental flume. The first results of the experimental research, concerning erosion time evolution, the influence of discharge and the distance travelled by the eroded sediments, will be presented and discussed.

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

USGS Publications Warehouse

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

2012-01-01

A study of the geomorphology of rivers draining Mount Rainier, Washington, was completed to identify sources of sediment to the river network; to identify important processes in the sediment delivery system; to assess current sediment loads in rivers draining Mount Rainier; to evaluate if there were trends in streamflow or sediment load since the early 20th century; and to assess how rates of sedimentation might continue into the future using published climate-change scenarios. Rivers draining Mount Rainier carry heavy sediment loads sourced primarily from the volcano that cause acute aggradation in deposition reaches as far away as the Puget Lowland. Calculated yields ranged from 2,000 tonnes per square kilometer per year [(tonnes/km2)/yr] on the upper Nisqually River to 350 (tonnes/km2)/yr on the lower Puyallup River, notably larger than sediment yields of 50–200 (tonnes/km2)/yr typical for other Cascade Range rivers. These rivers can be assumed to be in a general state of sediment surplus. As a result, future aggradation rates will be largely influenced by the underlying hydrology carrying sediment downstream. The active-channel width of rivers directly draining Mount Rainier in 2009, used as a proxy for sediment released from Mount Rainier, changed little between 1965 and 1994 reflecting a climatic period that was relatively quiet hydrogeomorphically. From 1994 to 2009, a marked increase in geomorphic disturbance caused the active channels in many river reaches to widen. Comparing active-channel widths of glacier-draining rivers in 2009 to the distance of glacier retreat between 1913 and 1994 showed no correlation, suggesting that geomorphic disturbance in river reaches directly downstream of glaciers is not strongly governed by the degree of glacial retreat. In contrast, there was a correlation between active-channel width and the percentage of superglacier debris mantling the glacier, as measured in 1971. A conceptual model of sediment delivery processes from the mountain indicates that rockfalls, glaciers, debris flows, and main-stem flooding act sequentially to deliver sediment from Mount Rainier to river reaches in the Puget Lowland over decadal time scales. Greater-than-normal runoff was associated with cool phases of the Pacific Decadal Oscillation. Streamflow-gaging station data from four unregulated rivers directly draining Mount Rainier indicated no statistically significant trends of increasing peak flows over the course of the 20th century. The total sediment load of the upper Nisqually River from 1945 to 2011 was determined to be 1,200,000±180,000 tonnes/yr. The suspended-sediment load in the lower Puyallup River at Puyallup, Washington, was 860,000±300,000 tonnes/yr between 1978 and 1994, but the long-term load for the Puyallup River likely is about 1,000,000±400,000 tonnes/yr. Using a coarse-resolution bedload transport relation, the long-term average bedload was estimated to be about 30,000 tonnes/yr in the lower White River near Auburn, Washington, which was four times greater than bedload in the Puyallup River and an order of magnitude greater than bedload in the Carbon River. Analyses indicate a general increase in the sediment loads in Mount Rainier rivers in the 1990s and 2000s relative to the time period from the 1960s to 1980s. Data are insufficient, however, to determine definitively if post-1990 increases in sediment production and transport from Mount Rainier represent a statistically significant increase relative to sediment-load values typical from Mount Rainier during the entire 20th century. One-dimensional river-hydraulic and sediment-transport models simulated the entrainment, transport, attrition, and deposition of bed material. Simulations showed that bed-material loads were largest for the Nisqually River and smallest for the Carbon River. The models were used to simulate how increases in sediment supply to rivers transport through the river systems and affect lowland reaches. For each simulation, the input sediment pulse evolved through a combination of translation, dispersion, and attrition as it moved downstream. The characteristic transport times for the median sediment-size pulse to arrive downstream for the Nisqually, Carbon, Puyallup, and White Rivers were approximately 70, 300, 80, and 60 years, respectively.

Effects of dam removal on Tule Fall Chinook salmon spawning habitat in the White Salmon River, Washington

USGS Publications Warehouse

Hatten, James R.; Batt, Thomas R.; Skalicky, Joseph J.; Engle, Rod; Barton, Gary J.; Fosness, Ryan L.; Warren, Joe

2016-01-01

Condit Dam is one of the largest hydroelectric dams ever removed in the USA. Breached in a single explosive event in October 2011, hundreds-of-thousands of cubic metres of sediment washed down the White Salmon River onto spawning grounds of a threatened species, Columbia River tule fall Chinook salmon Oncorhynchus tshawytscha. We investigated over a 3-year period (2010–2012) how dam breaching affected channel morphology, river hydraulics, sediment composition and tule fall Chinook salmon (hereafter ‘tule salmon’) spawning habitat in the lower 1.7 km of the White Salmon River (project area). As expected, dam breaching dramatically affected channel morphology and spawning habitat due to a large load of sediment released from Northwestern Lake. Forty-two per cent of the project area that was previously covered in water was converted into islands or new shoreline, while a large pool near the mouth filled with sediments and a delta formed at the mouth. A two-dimensional hydrodynamic model revealed that pool area decreased 68.7% in the project area, while glides and riffles increased 659% and 530%, respectively. A spatially explicit habitat model found the mean probability of spawning habitat increased 46.2% after dam breaching due to an increase in glides and riffles. Shifting channels and bank instability continue to negatively affect some spawning habitat as sediments continue to wash downstream from former Northwestern Lake, but 300 m of new spawning habitat (river kilometre 0.6 to 0.9) that formed immediately post-breach has persisted into 2015. Less than 10% of tule salmon have spawned upstream of the former dam site to date, but the run sizes appear healthy and stable. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

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

PubMed

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

2017-12-31

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

Channel evolution on the dammed Elwha River, Washington, USA

USGS Publications Warehouse

Draut, A.E.; Logan, J.B.; Mastin, M.C.

2011-01-01

Like many rivers in the western U.S., the Elwha River, Washington, has changed substantially over the past century in response to natural and human forcing. The lower river is affected by two upstream dams that are slated for removal as part of a major river restoration effort. In preparation for studying the effects of dam removal, we present a comprehensive field and aerial photographic analysis of dam influence on an anabranching, gravel-bed river. Over the past century with the dams in place, loss of the upstream sediment supply has caused spatial variations in the sedimentary and geomorphic character of the lower Elwha River channel. Bed sediment is armored and better sorted than on the naturally evolving bed upstream of the dams. On time scales of flood seasons, the channel immediately below the lower dam is fairly stable, but progresses toward greater mobility downstream such that the lowermost portion of the river responded to a recent 40-year flood with bank erosion and bed-elevation changes on a scale approaching that of the natural channel above the dams. In general, channel mobility in the lowest 4 km of the Elwha River has not decreased substantially with time. Enough fine sediment remains in the floodplain that – given sufficient flood forcing – the channel position, sinuosity, and braiding index change substantially. The processes by which this river accesses new fine sediment below the dams (rapid migration into noncohesive banks and avulsion of new channels) allow it to compensate for loss of upstream sediment supply more readily than would a dammed river with cohesive banks or a more limited supply of alluvium. The planned dam removal will provide a valuable opportunity to evaluate channel response to the future restoration of natural upstream sediment supply.

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

NASA Astrophysics Data System (ADS)

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

2014-05-01

Gravel bed rivers are environments shaped by the balance of flow, sediment regimes, large wood (LW) and vegetation. Geomorphic changes are response to fluctuations and changes of runoff and sediment supply involving mutual interactions among these factors. Typically, many natural disasters (i.e. debris flows, floods and forest fires) can affect the river basin dynamics. Explosive volcanic eruptions present, instead, the potential of exerting severe impacts as, for example, filling river valleys or changing river network patterns thanks to massive deposition of tephra and volcanic sediment all over the main channel and over the basin. These consistent impacts can strongly affect both hydrology and sediment transport dynamics, all over the river system, producing huge geomorphic changes. During the last years there has been a consistent increase in the survey technologies that permit to monitor geomorphic changes and to estimate sediment budgets through repeat topographic surveys. The calculation of differences between subsequent DEMs (difference of DEMs, DoD) is a commonly applied method to analyze and quantify these dynamics. Typically the higher uncertainty values are registered in areas with higher topographic variability and lower point density. This research was conducted along a ~ 2.2 km-long sub-reach of the Blanco River (Southern Chile), a fourth-order stream that presents a mainly rainfall regime with winter peak flows. The May 2008 Chaitén volcanic eruption strongly affected the entire Rio Blanco basin. The entire valley was highly exposed to the pyroclastic and fluvial flows, which affected directly a consistent area of evergreen forests. Extreme runoff from the upper Blanco catchment aggraded the channel and deposited up to several meters of tephra, alluvium, and LW along the entire river system. Aims of this contribution are to define and quantify the short term evolution of the Blanco River after the big eruption event and a subsequent consistent flood that happened in 2013. A post eruption airborne LiDAR data set (2009) and two different Terrestrial Laser Scanner (TLS) surveys carried out in 2013 and 2014 have been used to investigate this. We applied an approach to assessing spatially variable uncertainty in DoDs computation that is based on the creation of an ad hoc fuzzy inference system (FIS) that permits us to combine individually errors of different sources. Particularly attention was applied to define a new approach that permit to filter the huge amount of LW present into the active channel, depending on the superficial roughness values. After the LW filtering, the very high point clouds density allowed us to derive three high resolution DEMs. Topographic data were more accurate for exposed surfaces than those collected in wet areas. Two DoDs were computed, showing consistent erosion processes and deposition within the study area, and changes in geomorphic characteristics of channel and bars could also be detected, demonstrating a strong dynamicity of the study reach. This research is been developed within the framework of Project FONDECYT 1110609. Project "SedAlp: sediment management in Alpine basins, integrating sediment continuum, risk mitigation and hydropower", 83-4-3-AT, in the framework of the European Territorial Cooperation Program "Alpine Space" 2007-2013.

[Effects of Perfluoroalkyl Substances on the Microbial Community Structure in Surface Sediments of Typical River, China].

PubMed

Sun, Ya-jun; Wang, Tie-yu; Peng, Xia-wei; Wang, Pei

2015-07-01

In order to reveal the relationship between Perfluoroalkyl substances (PFASs) contamination and the bacterial community composition, surface sediment samples were collected along the Xiaoqing River in Shandong Province in April and July 2014 (XQ1-XQ10), where many PFASs manufacturers were located. PFASs were quantified by HPLC/MS-MS, related environmental factors affecting the microbial community structure were measured, and the microbial community structure in surface sediments was measured by the second-generation sequencing technology Illumina MiSeq. The results not only revealed the degree of PFASs pollution in the sediments of Xiaoqing River, but also illustrated the relationship between PFASs pollution and the microbial community structure. Among the twelve kinds of PFASs detected in this study, PFOA was the predominant compound, and the highest PFOA concentrations were detected in the sample of XQ5 (April: 456. 2 ng. g-1; July: 748.7 ng . g-1) located at the downstream of Xiaoqing River with many fluoropolymer producing facilities. PFOA contamination was the main factor affecting the microbial community structure in April, accordingly community richness and evenness were significantly negatively correlated with PFOA levels. The abundance of Thiobacillus increased with the increasing PFOA concentration in the sediment PFOA. This suggested that Thiobacillus was sensitive to PFOA pollution and might be the potential indicator to reveal the degree of PFOA pollution in sediment. When the concentrations of PFOA were below 100 ng . g-1, no significant effects on the microbial community structure were observed.

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

NASA Astrophysics Data System (ADS)

Griffiths, Ronald E.; Topping, David J.

2017-11-01

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

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

USGS Publications Warehouse

Griffiths, Ronald; Topping, David

2017-01-01

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

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

PubMed

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

2016-11-01

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

Balancing hydropower production and river bed incision in operating a run-of-river hydropower scheme along the River Po

NASA Astrophysics Data System (ADS)

Denaro, Simona; Dinh, Quang; Bizzi, Simone; Bernardi, Dario; Pavan, Sara; Castelletti, Andrea; Schippa, Leonardo; Soncini-Sessa, Rodolfo

2013-04-01

Water management through dams and reservoirs is worldwide necessary to support key human-related activities ranging from hydropower production to water allocation, and flood risk mitigation. Reservoir operations are commonly planned in order to maximize these objectives. However reservoirs strongly influence river geomorphic processes causing sediment deficit downstream, altering the flow regime, leading, often, to process of river bed incision: for instance the variations of river cross sections over few years can notably affect hydropower production, flood mitigation, water supply strategies and eco-hydrological processes of the freshwater ecosystem. The river Po (a major Italian river) has experienced severe bed incision in the last decades. For this reason infrastructure stability has been negatively affected, and capacity to derive water decreased, navigation, fishing and tourism are suffering economic damages, not to mention the impact on the environment. Our case study analyzes the management of Isola Serafini hydropower plant located on the main Po river course. The plant has a major impact to the geomorphic river processes downstream, affecting sediment supply, connectivity (stopping sediment upstream the dam) and transport capacity (altering the flow regime). Current operation policy aims at maximizing hydropower production neglecting the effects in term of geomorphic processes. A new improved policy should also consider controlling downstream river bed incision. The aim of this research is to find suitable modeling framework to identify an operating policy for Isola Serafini reservoir able to provide an optimal trade-off between these two conflicting objectives: hydropower production and river bed incision downstream. A multi-objective simulation-based optimization framework is adopted. The operating policy is parameterized as a piecewise linear function and the parameters optimized using an interactive response surface approach. Global and local response surface are comparatively assessed. Preliminary results show that a range of potentially interesting trade-off policies exist able to better control river bed incision downstream without significantly decreasing hydropower production.

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

PubMed

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

2012-01-01

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

Processes affecting suspended sediment transport in the mid-field plume region of the Rhine River, Netherlands.

NASA Astrophysics Data System (ADS)

Flores, R. P.; Rijnsburger, S.; Horner-Devine, A.; Souza, A. J.; Pietrzak, J.

2016-02-01

This work will describe dominant processes affecting suspended sediment transport along the Dutch coast, in the mid-field plume region of the Rhine River. We will present field observations from two long-term deployments conducted in the vicinity of the Sand Engine, a mega-nourishment experiment located 10 km north of the Rhine river mouth. To investigate the role of density stratification, winds, tides, waves and river plume processes on sediment transport, frames and moorings were deployed within the excursion of the tidal plume front generated by the freshwater outflow from the Rhine River for 4 and 6 weeks during years 2013 and 2014, respectively. The moorings were designed to measure vertical profiles of suspended sediment concentration (SSC) and salinity, using arrays of CTDs and OBS sensors. Mean tidal velocities were measured using bottom-mounted ADCPs. The near-bed dynamics and the near-bottom sediment concentrations were measured as well using a set of synchronized ADVs and OBSs. By combining the two deployments we observe hydrodynamics and suspended sediment dynamics under a wide range of forcing conditions. Preliminary observations indicate that stratification is highly dependent on wind magnitude and direction, and its role is primarily identified as to induce significant cross-shore sediment transport product of the generation of cross-shore velocities due to the modification of the tidal ellipses and the passage of the surface plume front. The passage of the surface plume front generates strong offshore currents near the bottom, producing transport events that can be similar in magnitude to the dominant alongshore transport. Preliminary results also indicate that storms play an important role in alongshore transport primarily by wave-induced sediment resuspension, but as stratification is suppressed due to the enhancement of mixing processes, no significant cross-shore transport is observed during very energetic conditions.

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

NASA Astrophysics Data System (ADS)

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

2016-12-01

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

Spatial distribution of chemical constituents in the Kuskokwim River, Alaska

USGS Publications Warehouse

Wang, Bronwen

1999-01-01

The effects of lithologic changes on the water quality of the Kuskokwim River, Alaska, were evaluated by the U.S. Geological Survey in June 1997. Water, suspended sediments, and bed sediments were sampled from the Kusko-kwim River and from three tributaries, the Holitna River, Red Devil Creek, and Crooked Creek. Dissolved boron, chromium, copper, manganese, zinc, aluminum, lithium, barium, iron, antimony, arsenic, mercury, and strontium were detected. Dissolved manganese and iron concentrations were three and four times higher in the Holitna River than in the Kusko-kwim River. Finely divided ferruginous materials found in the graywacke and shale units of the Kuskokwim Group are the probable source of the iron. The highest concentrations of dissolved strontium and barium were found at McGrath, and the limestone present in the upper basin was the most probable source of strontium. The total mercury concentrations on the Kuskokwim River decreased downstream from McGrath. Dissolved mercury was 24 to 32 percent of the total concentration. The highest concentrations of total mercury, and of dissolved antimony and arsenic were found in Red Devil Creek. The higher concentrations from Red Devil Creek did not affect the main stem mercury transport because the tributary was small relative to the Kuskokwim River. In Red Devil Creek, total mercury exceeded the concentration at which the U.S. Environmental Protection Agency (USEPA) indicates that aquatic life is affected and dissolved arsenic exceeded the USEPA's drinking-water standard. Background mercury and antimony concentrations in bed sediments ranged from 0.09 to 0.15 micrograms per gram for mercury and from 1.6 to 2.1 micrograms per gram for antimony. Background arsenic concentrations were greater than 27 micrograms per gram. Sites near the Red Devil mercury mine had mercury and antimony concentrations greater than background concentrations. These concentrations probably reflect the proximity to the ore body and past mining. Crooked Creek had mercury concentrations greater than the background concentration. The transport of suspended sediment-associated trace elements was lower for all elements in the lower river than in the upper river, indicating storage of sediments and their associated metals within the river system.

Ecosystem effects in the Lower Mississippi River Basin: Chapter L in 2011 Floods of the Central United States

USGS Publications Warehouse

Turnipseed, D. Phil; Allen, Yvonne C.; Couvillion, Brady R.; McKee, Karen L.; Vervaeke, William C.

2014-01-01

The 2011 Mississippi River flood in the Lower Mississippi River Basin was one of the largest flood events in recorded history, producing the largest or next to largest peak streamflow for the period of record at a number of streamgages on the lower Mississippi River. Ecosystem effects include changes to wetlands, nutrient transport, and land accretion and sediment deposition changes. Direct effects to the wetland ecosystems in the Lower Mississippi River Basin were minimized because of the expansive levee system built to pass floodwaters. Nutrients carried by the Mississippi River affect water quality in the Lower Mississippi River Basin. During 2011, nutrient fluxes in the lower Mississippi River were about average. Generally, nutrient delivery of the Mississippi and Atchafalaya Rivers contributes to the size of the hypoxic zone in the Gulf of Mexico. Based on available limited post-flood satellite imagery, some land expansion in both the Wax Lake and Atchafalaya River Deltas was observed. A wetland sediment survey completed in June 2011 indicated that recent sediment deposits were relatively thicker in the Atchafalaya and Mississippi River (Birdsfoot) Delta marshes compared to marshes farther from these rivers.

Occurrence of Organic Compounds and Trace Elements in the Upper Passaic and Elizabeth Rivers and Their Tributaries in New Jersey, July 2003 to February 2004: Phase II of the New Jersey Toxics Reduction Workplan for New York-New Jersey Harbor

USGS Publications Warehouse

Wilson, Timothy P.; Bonin, Jennifer L.

2008-01-01

Samples of surface water and suspended sediment were collected from the Passaic and Elizabeth Rivers and their tributaries in New Jersey from July 2003 to February 2004 to determine the concentrations of selected chlorinated organic and inorganic constituents. This sampling and analysis was conducted as Phase II of the New York-New Jersey Harbor Estuary Workplan?Contaminant Assessment and Reduction Program (CARP), which is overseen by the New Jersey Department of Environmental Protection. Phase II of the New Jersey Workplan was conducted to define upstream tributary and point sources of contaminants in those rivers sampled during Phase I work, with special emphasis on the Passaic and Elizabeth Rivers. Samples were collected from three groups of tributaries: (1) the Second, Third, and Saddle Rivers; (2) the Pompton and upper Passaic Rivers; and (3) the West Branch and main stem of the Elizabeth River. The Second, Third, and Saddle Rivers were sampled near their confluence with the tidal Passaic River, but at locations not affected by tidal flooding. The Pompton and upper Passaic Rivers were sampled immediately upstream from their confluence at Two Bridges, N.J. The West Branch and the main stem of the Elizabeth River were sampled just upstream from their confluence at Hillside, N.J. All tributaries were sampled during low-flow discharge conditions using the protocols and analytical methods for organic constituents used in low-flow sampling in Phase I. Grab samples of streamflow also were collected at each site and were analyzed for trace elements (mercury, methylmercury, cadmium, and lead) and for suspended sediment, particulate organic carbon, and dissolved organic carbon. The measured concentrations and available historical suspended-sediment and stream-discharge data (where available) were used to estimate average annual loads of suspended sediment and organic compounds in these rivers. Total suspended-sediment loads for 1975?2000 were estimated using rating curves developed from historical U.S. Geological Survey (USGS) suspended-sediment and discharge data, where available. Average annual loads of suspended sediment, in millions of kilograms per year (Mkg/yr), were estimated to be 0.190 for the Second River, 0.23 for the Third River, 1.00 for the Saddle River, 1.76 for the Pompton River, and 7.40 for the upper Passaic River. On the basis of the available discharge records, the upper Passaic River was estimated to provide approximately 60 percent of the water and 80 percent of the total suspended-sediment load at the Passaic River head-of-tide, whereas the Pompton River provided roughly 20 percent of the total suspended-sediment load estimated at the head-of-tide. The combined suspended-sediment loads of the upper Passaic and Pompton Rivers (9.2 Mkg/yr), however, represent only 40 percent of the average annual suspended-sediment load estimated for the head-of-tide (23 Mkg/yr) at Little Falls, N.J. The difference between the combined suspended-sediment loads of the tributaries and the estimated load at Little Falls represents either sediment trapped upriver from the dam at Little Falls, additional inputs of suspended sediment downstream from the tributary confluence, or uncertainty in the suspended-sediment and discharge data that were used. The concentrations of total suspended sediment-bound polychlorinated biphenyls (PCBs) in the tributaries to the Passaic River were 194 ng/g (nanograms per gram) in the Second River, 575 ng/g in the Third River, 2,320 ng/g in the Saddle River, 200 ng/g in the Pompton River, and 87 ng/g in the upper Passic River. The dissolved PCB concentrations in the tributaries were 563 pg/L (picograms per liter) in the Second River, 2,510 pg/L in the Third River, 2,270 pg/L in the Saddle River, 887 pg/L in the Pompton River, and 1,000 pg/L in the upper Passaic River. Combined with the sediment loads and discharge, these concentrations resulted in annual loads of suspended sediment-bound PCBs, i

Selenium in Reservoir Sediment from the Republican River Basin

USGS Publications Warehouse

Juracek, Kyle E.; Ziegler, Andrew C.

1998-01-01

Reservoir sediment quality is an important environmental concern because sediment may act as both a sink and a source of water-quality constituents to the overlying water column and biota. Once in the food chain, sediment-derived constituents may pose an even greater concern due to bioaccumulation. An analysis of reservoir bottom sediment can provide historical information on sediment deposition as well as magnitudes and trends in constituents that may be related to changes in human activity in the basin. The assessment described in this fact sheet was initiated in 1997 by the U.S. Geological Survey (USGS), in cooperation with the Bureau of Reclamation (BOR), U.S. Department of the Interior, to determine if irrigation activities have affected selenium concentrations in reservoir sediment of the Republican River Basin of Colorado, Kansas, and Nebraska.

Factors affecting distribution patterns of organic carbon in sediments at regional and national scales in China.

PubMed

Cao, Qingqing; Wang, Hui; Zhang, Yiran; Lal, Rattan; Wang, Renqing; Ge, Xiuli; Liu, Jian

2017-07-14

Wetlands are an important carbon reservoir pool in terrestrial ecosystems. Light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), and dissolved organic carbon (DOC) were fractionated in sediment samples from the four wetlands (ZR: Zhaoniu River; ZRCW: Zhaoniu River Constructed Wetland; XR: Xinxue River; XRCW: Xinxue River Constructed Wetland). Organic carbon (OC) from rivers and coasts of China were retrieved and statistically analyzed. At regional scale, HFOC stably dominates the deposition of OC (95.4%), whereas DOC and LFOC in ZR is significantly higher than in ZRCW. Concentration of DOC is significantly higher in XRCW (30.37 mg/l) than that in XR (13.59 mg/l). DOC and HFOC notably distinguish between two sampling campaigns, and the deposition of carbon fractions are limited by low nitrogen input. At the national scale, OC attains the maximum of 2.29% at precipitation of 800 mm. OC has no significant difference among the three climate zones but significantly higher in river sediments than in coasts. Coastal OC increases from Bohai Sea (0.52%) to South Sea (0.70%) with a decrease in latitude. This study summarizes the factors affecting organic carbon storage in regional and national scale, and have constructive implications for carbon assessment, modelling, and management.

Water chemistry in the rives of the permafrost regions on the eastern Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wu, X.; Ma, X.; Ye, L.; Liu, G.

2017-12-01

Qinghai-Tibetan is the largest middle-low latitude permafrost areas on the world. There are several large rivers in the plateau, and the changes of the water resources of these rivers are associated with the water resource security of more than 1.35 billion people. Due to the high gradients, these rivers have a tremendous amount of potential energy for electricity output. To promote economic and social development and provide clean energy, hydropower development has taken place on several rivers which originate on the Qinghai-Tibetan Plateau. Since dam construction affect the flow velocity, water temperature, sediments delivery as well as organic matter and nitrogen, it is important to investigate the river chemistry in the head rivers of the reservoirs. We examined the water physio-chemical characteristics in the rivers under the typical vegetation types in the eastern Qinghai-Tibetan Plateau, and further analyzed their relationship to vegetation. The results showed that the total suspended sediment in the rivers were higher within the catchment of alpine steppe, with the lowest dissolved organic carbon content. In contrast, the rivers within the meadow had the highest dissolved organic carbon and lowest total suspension sediment. The dissolved organic carbon significantly positively correlated with the proportions of the meadow and wet meadow in the catchment. The pH, turbidity, and SUVA254 and dissolved organic carbon also correlated with each other. The results suggest that the vegetation type strongly affect the water chemistry in the permafrost regions on the Qinghai-Tibetan Plateau.

Magnified Sediment Export of Small Mountainous Rivers in Taiwan: Chain Reactions from Increased Rainfall Intensity under Global Warming.

PubMed

Lee, Tsung-Yu; Huang, Jr-Chuan; Lee, Jun-Yi; Jien, Shih-Hao; Zehetner, Franz; Kao, Shuh-Ji

2015-01-01

Fluvial sediment export from small mountainous rivers in Oceania has global biogeochemical significance affecting the turnover rate and export of terrestrial carbon, which might be speeding up at the recognized conditions of increased rainfall intensity. In this study, the historical runoff and sediment export from 16 major rivers in Taiwan are investigated and separated into an early stage (1970-1989) and a recent stage (1990-2010) to illustrate the changes of both runoff and sediment export. The mean daily sediment export from Taiwan Island in the recent stage significantly increased by >80% with subtle increase in daily runoff, indicating more sediment being delivered to the ocean per unit of runoff in the recent stage. The medians of the runoff depth and sediment yield extremes (99.0-99.9 percentiles) among the 16 rivers increased by 6.5%-37% and 62%-94%, respectively, reflecting the disproportionately magnified response of sediment export to the increased runoff. Taiwan is facing increasing event rainfall intensity which has resulted in chain reactions on magnified runoff and sediment export responses. As the globe is warming, rainfall extremes, which are proved to be temperature-dependent, very likely intensify runoff and trigger more sediment associated hazards. Such impacts might occur globally because significant increases of high-intensity precipitation have been observed not only in Taiwan but over most land areas of the globe.

Stratigraphy, sedimentology, and volume of sediments behind a dam relic on the Muskegon River, Big Rapids, Michigan

USGS Publications Warehouse

Westjohn, David B.

1997-01-01

The proposed removal of the remnants of a hydroelectric dam in the Muskegon River at Big Rapids, Michigan, will potentially affect flow of the river at the city's water intake system. Fifteen boreholes were augered in bottom sediments in the river just upstream from the dam relic, and streambottom profiles were made using ground-penetrating radar. Data from boreholes show that sediments captured by the dam foundation were deposited in two distinctly different sedimentary environments. Sediments that overlie the pre-dam channel surface consist of lacustrine clay, wood chips, silt, and sand. These lacustrine sediments are interbedded in a cyclical fashion, and they were deposited under low flow to stagnant water conditions during 1916-66, when a 17-foot-tall hydroelectric dam was in place. Demolition of the upper 13 feet of this dam in 1966 resulted in erosion of most of the lacustrine sediments, and subsequent deposition of coarser alluvium in the impoundment behind the remaining dam foundation. Lacustrine sediments are present in the active part of the stream channel and extend from the dam foundation to about 1,300 feet upstream. The composite thickness of lacustrine sediments and overlying coarser alluvium was determined from sediment cores collected from the boreholes. The volume of these sediments is estimated to be about 19,000 cubic yards.

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

USGS Publications Warehouse

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

2016-09-20

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

Human Impact on the Geomorphological Evolution of the Opak River Following the 2010 Large Volcanic Event of the Merapi (Indonesia)

NASA Astrophysics Data System (ADS)

Gob, F.; Gautier, E.; Virmoux, C.; Grancher, D.; Tamisier, V.; Primanda, K. W.; Wibowo, S. B.

2016-12-01

During large eruptions, active volcanos may introduce very large quantities of sediment to the drainage system through tephra falls and pyroclastic flows, thus modifying the river system. Once remobilized, the sediment inputs propagate downstream as a sediment wave modifying the channel geometry of the river and reloading the sediment cascade of the catchments. Considering the extreme nature of the volcanic events, the parameters that control the post-eruption evolution of the river system are generally only described as natural and the role played by human activities seems negligible. Communities that live on the volcano slopes and foothills are rather considered to suffer from natural disasters associated with the eruption and its consequences (lahars, etc.) or take advantage of the benefits of the volcanic environment (rich soil, mining and geothermal resources, etc.). This study examines the impact of human influence on the fluvial readjustment of a Javanese river impacted by a major eruption of the Merapi volcano (Indonesia) in October/November 2010. The basin of the Opak River was subject to substantial sediment input related to massive pyroclastic deposits that were remobilized by numerous lahars during the year after the eruption. Two study sites were equipped in order to evaluate the morphodynamic evolution of the riverbed of the Opak River. Topographic surveys, bedload particle marking and suspended sediment sampling revealed an important sediment mobilization during efficient flash-floods. Surprisingly, no bed aggradation related to the progradation of a sediment wave was observed. Two years after the eruptive event, marked bed incision was observed. The Opak River readjustment differs from that of other fluvial systems affected by massive eruptions in two ways. Firstly, the local population massively extracted the sand and blocks injected by the eruption as they represent a valuable economic resource. Secondly, several dams trapped the major part of the sediment load remobilized by lahars.

[Characteristic of ammonia nitrogen adsorption on karst underground river sediments].

PubMed

Guo, Fang; Chen, Kun-Kun; Jiang, Guang-Hui

2011-02-01

Karst aquifers are one of the most important aquifers in Southwestern China. One of the characteristics of karst aquifers is the enhanced permeability permits high flow velocities are capable of transporting suspended and bedload sediments. Mobile sediment in karst may act as a vector for the transport of contaminates. 14 sediment samples were collected from two underground rivers in two typical karst areas in Liuzhou city, Guangxi Autonomous Region, China. According to simulated experiment methods, characteristic of adsorption of ammonia nitrogen on sediment was studied. The results of ammonia nitrogen adsorption dynamics on sediments showed that the maximum adsorption velocity was less than 2 h. The adsorption balance quantity in 5 h accounted for 71% - 98% of the maximum adsorption quantity. The maximum adsorption quantity of ammonia nitrogen was 385.5 mg/kg, which was sediment from a cave in the middle areas of Guancun underground river system. The study of isotherm adsorption indicated adsorption quantity of NH4+ increase followed by incremental balance concentration of NH4+ in the aquatic phase. Adsorption quantity of ammonia nitrogen in sediments has a relative linear relationship with adsorption balance concentrations. Adsorption-desorption balance concentrations were all low, indicating sediments from underground rivers have great adsorption potential. Under the condition of low and high concentrations of ammonia nitrogen in overlying water, Langmuir and Tempkin couldn't simulate or simulate results couldn't reach remarkable level, whilst Linear and Freundlich models could simulate well. Research on different type sediments, sampling times and depths from two underground rivers shows characteristic of ammonia nitrogen adsorption on karst underground river sediments doesn't have good correspondence with the type of sediments. One of the reasons is there is no big difference between sediments in the development of climate, geology, hydrological conditions and pollution history. The other reason maybe the article is lack of research on pH, salinity and others factors which may affect adsorption and desorption.

Progress report on the effects of highway construction on suspended-sediment discharge in the Coal River and Trace Fork, West Virginia, 1975-81

USGS Publications Warehouse

Downs, S.C.; Appel, David H.

1986-01-01

Construction of the four-lane Appalachian Corridon G highway disturbed about 2 sq mi in the Coal River and 0.35 sq mi of the 4.75 sq mi Trace Fork basin in southern West Virginia. Construction had a negligible effect on runoff and suspended-sediment load in the Coal River and its major tributaries, the Little Coal and Big Coal Rivers. Drainage areas of the mainstem sites in the Coal River basin ranged from 269 to 862 sq mi, and average annual suspended-sediment yields ranged from 535 to 614 tons/sq mi for the 1975-81 water years. Suspended-sediment load in the smaller Trace Fork basin (4.72 sq mi) was significantly affected by the highway construction. Based on data from undisturbed areas upstream from construction, the normal background load at Trace Fork downstream from construction during the period July 1980 to September 1981 was estimated to be 830 tons; the measured load was 2,385 tons. Runoff from the 0.35 sq mi area disturbed by highway construction transported approximately 1,550 tons of sediment. Suspended-sediment loads from the construction zone were also higher than normal background loads during storms. (USGS)

A catchment-integrated approach to determine the importance of secondary sources of contaminated sediment

NASA Astrophysics Data System (ADS)

Andres Lopez-Tarazon, Jose; Byrne, Patrick; Mullan, Donal; Smith, Hugh

2015-04-01

Water pollution has been identified as one of the most important environmental challenges of the early 21st Century. The Water Framework Directive (WFD) (2008/105/EC) explicitly recognises the risk to water resources posed by sediment-associated contaminants in European river basins. The potential impacts on water supply and the biodiversity of aquatic ecosystems from sediment and associated contaminants may be further exacerbated by climate change pressures on water resources, as highlighted in the 2009 EU White Paper "Adapting to climate change: Towards a European framework for action" (SEC(2009) 386, 387, 388). Despite these concerns, the role of floodplains and other storage areas as secondary sources of contaminated sediment (i.e. metals) in river basins affected by historic industrial or mining pollution has been largely overlooked. Thereby, besides the sediment which is transported by the river, secondary sources of contaminants represent a credible threat to achieving EU water quality targets set by the WFD. This project addresses this issue by developing a catchment-based approach looking at metal geochemistry from source to sink (i.e., from sediment generation at slopes, passing through sediment transported by the river system, to sediment deposition at the storage areas to the outlet) and develop a geochemical model to predict the chemical aspects of metals transport and transformation. This approach will allow us to quantify (i) the sediment fluxes and associated contaminants flowing through the river, (ii) the storage areas contributions to downstream contaminated sediment fluxes, (ii) the timescales for the storage and removal of contaminated sediment in the sinks, and (iv) the transformation and bioavailability of the pollutants (i.e. metals) along the basin. Both physical and chemical aspects of metal transport will be considered by looking at metal geochemistry, mobility and bioavailability, hence producing information on chemical metal transport and transformation from source to sink. Different metal species rather than bulk metals will be investigated providing information on potential metal mobility (and what environmental processes might force mobility) and bioavailability. Biological work (i.e. macroinvertebrates samplings, PCA and CCA techniques) will also carried out to apply contaminant-ecosystem models and determine the affectation of pollutants over the biology/ecology. Finally, catchment-based hydro-sedimentological models will be applied to study how different global-change scenarios could alter sediment (and hence) metals transport. This way, present work will generate better understanding of the environmental risk derived from sediment mobility in contaminated systems, a critical information which will provide river basin managers with the means to assess the potential impact of the secondary sources of water pollution in European rivers.

Export Time of Earthquake-Derived Landslides in Active Mountain Ranges

NASA Astrophysics Data System (ADS)

Croissant, T.; Lague, D.; Steer, P.; Davy, P.

2016-12-01

In active mountain ranges, large earthquakes (Mw > 5-6) trigger numerous landslides that impact river dynamics. These landslides bring local and sudden sediment deposits which are eroded and transported along the river network, causing downstream changes in river geometry, transport capacity and erosion efficiency. The progressive removal of landslide materials has implications for downstream hazards management and for landscape dynamics at the timescale of the seismic cycle. Although the export time of suspended sediments from landslides triggered by large-magnitude earthquakes has been extensively studied, the processes and time scales associated to bedload transport remains poorly studied. Here, we study the sediment export of large landslides with the 2D morphodynamic model, Eros. This model combines: (i) an hydrodynamic model, (ii) a sediment transport and deposition model and (iii) a lateral erosion model. Eros is particularly well suited for this issue as it accounts for the complex retro-actions between sediment transport and fluvial geometry for rivers submitted to external forcings such as abrupt sediment supply increase. Using a simplified synthetic topography we systematically study the influence of pulse volume (Vs) and channel transport capacity (QT) on the export time of landslides. The range of simulated river behavior includes landslide vertical incision, its subsequent removal by lateral erosion and the river morphology modifications induced by downstream sediment propagation. The morphodynamic adaptation of the river increases its transport capacity along the channel and tends to accelerate the landslide evacuation. Our results highlight two regimes: (i) the export time is linearly related to Vs/QT when the sediment pulse introduced in the river does not affect significantly the river hydrodynamic (low Vs/QT) and (ii) the export time is a non-linear function of Vs/QT when the pulse undergoes significant morphodynamic modifications during its evacuation (high Vs/QT). By combining our newly derived export time functions with the frequency-magnitude of earthquake intensity and the induced sediment production, we investigate the sediment export of several plausible earthquake scenarii in different mountain ranges (New Zealand, Taiwan, Nepal).

Effects of mining activities on heavy metal concentrations in water, sediment, and macroinvertebrates in different reaches of the Pilcomayo River, South America.

PubMed

Smolders, A J P; Lock, R A C; Van der Velde, G; Medina Hoyos, R I; Roelofs, J G M

2003-04-01

From 1997 until 1999 the extent and the ecological effects of zinc, copper, lead, and cadmium pollution were studied in different reaches of the South American Pilcomayo River. A comparison of metal concentrations in water, sediment, and chironomid larvae, as well as the diversity of macroinvertebrate species, was made between sites near the origin of the Pilcomayo River, with hardly any mining activities, sites in the Potosí region, with intensive mining, and sites located 500 km or further downstream of Potosí, in the Chaco plain. Samples were also collected in an unpolluted river (Cachi Mayu River) and in the Tarapaya River, which is strongly contaminated by mine tailings (1000 tons a day). The upper parts of the Pilcomayo River are strongly affected by the release of mine tailings from the Potosí mines where mean concentrations of lead, cadmium, copper, and zinc in water, filtered water, sediment, and chironomid larvae were up to a thousand times higher than the local background levels. The diversity of the benthic macroinvertebrate community was strongly reduced in the contaminated parts; 97% of the benthic macroinvertebrates consisted of chironomid larvae. The degree of contamination in the lower reaches of the river, however, was fairly low because of sedimentation processes and the strong dilution of mine tailings with enormous amounts of clean sediment from erosion processes. Analysis of sediment cores from the Ibibobo floodplain, however, reveal an increase of the heavy metal concentrations in the lower reaches since the introduction of the contaminating flotation process in the mine industry in 1985.

Antibiotics in water and sediments of rivers and coastal area of Zhuhai City, Pearl River estuary, south China.

PubMed

Li, Si; Shi, Wanzi; Li, Huimin; Xu, Nan; Zhang, Ruijie; Chen, Xuejiao; Sun, Weiling; Wen, Donghui; He, Shanliang; Pan, Jianguo; He, Zhidong; Fan, Yingying

2018-09-15

The occurrence, spatiotemporal distribution and ecological risks of 27 antibiotics in water and sediments from rivers and coastal area of Zhuhai, Pearl River estuary, south China were investigated. Higher concentrations of antibiotics were found in river water in dry season than those in wet season (p < 0.01), especially for quinolones (QNs) (6.36-463 ng/L) and aminoglycosides (AGs) (94.9-458 ng/L). In coastal water samples, the concentrations of antibiotics were up to 419 ng/L and 357 ng/L in dry season and wet season, respectively. Higher concentrations of antibiotics in coastal sediment samples were observed in wet season compared with those in dry season (p < 0.01). This may be ascribed to the greater discharge of antibiotics from mariculture and surface sediment flushing in wet season, leading to the accumulation of polluted sediments in the estuary. Redundancy analysis showed that the concentrations of antibiotics in water were correlated with biological/chemical oxygen demand, ammonia nitrogen, and/or total nitrogen (TN). In addition, sediment organic matter (SOC) and TN strongly affected the distribution of antibiotics in sediments. Ecological risk assessment based on risk quotients (RQs) indicated that most antibiotics in water samples posed insignificant risk to fish and green algae, and insignificant to medium risk to daphnid. Copyright © 2018 Elsevier B.V. All rights reserved.

Seasonal hyporheic dynamics control coupled microbiology and geochemistry in Colorado River sediments

DOE PAGES

Danczak, Robert E.; Sawyer, Audrey H.; Williams, Kenneth H.; ...

2016-12-03

Riverbed microbial communities play an oversized role in many watershed ecosystem functions, including the processing of organic carbon, cycling of nitrogen, and alterations to metal mobility. The structure and activity of microbial assemblages depend in part on geochemical conditions set by river-groundwater exchange or hyporheic exchange. In order to assess how seasonal changes in river-groundwater mixing affect these populations in a snowmelt-dominated fluvial system, vertical sediment and pore water profiles were sampled at three time points at one location in the hyporheic zone of the Colorado River and analyzed by using geochemical measurements, 16S rRNA gene sequencing, and ecological modeling.more » Oxic river water penetrated deepest into the subsurface during peak river discharge, while under base flow conditions, anoxic groundwater dominated shallower depths. Over a 70 cm thick interval, riverbed sediments were therefore exposed to seasonally fluctuating redox conditions and hosted microbial populations statistically different from those at both shallower and deeper locations. Additionally, microbial populations within this zone were shown to be the most dynamic across sampling time points, underlining the critical role that hyporheic mixing plays in constraining microbial abundances. Given such mixing effects, we anticipate that future changes in river discharge in mountainous, semiarid western U.S. watersheds may affect microbial community structure and function in riverbed environments, with potential implications for biogeochemical processes in riparian regions.« less

Seasonal hyporheic dynamics control coupled microbiology and geochemistry in Colorado River sediments

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

Danczak, Robert E.; Sawyer, Audrey H.; Williams, Kenneth H.

Riverbed microbial communities play an oversized role in many watershed ecosystem functions, including the processing of organic carbon, cycling of nitrogen, and alterations to metal mobility. The structure and activity of microbial assemblages depend in part on geochemical conditions set by river-groundwater exchange or hyporheic exchange. In order to assess how seasonal changes in river-groundwater mixing affect these populations in a snowmelt-dominated fluvial system, vertical sediment and pore water profiles were sampled at three time points at one location in the hyporheic zone of the Colorado River and analyzed by using geochemical measurements, 16S rRNA gene sequencing, and ecological modeling.more » Oxic river water penetrated deepest into the subsurface during peak river discharge, while under base flow conditions, anoxic groundwater dominated shallower depths. Over a 70 cm thick interval, riverbed sediments were therefore exposed to seasonally fluctuating redox conditions and hosted microbial populations statistically different from those at both shallower and deeper locations. Additionally, microbial populations within this zone were shown to be the most dynamic across sampling time points, underlining the critical role that hyporheic mixing plays in constraining microbial abundances. Given such mixing effects, we anticipate that future changes in river discharge in mountainous, semiarid western U.S. watersheds may affect microbial community structure and function in riverbed environments, with potential implications for biogeochemical processes in riparian regions.« less

Seasonal hyporheic dynamics control coupled microbiology and geochemistry in Colorado River sediments

NASA Astrophysics Data System (ADS)

Danczak, Robert E.; Sawyer, Audrey H.; Williams, Kenneth H.; Stegen, James C.; Hobson, Chad; Wilkins, Michael J.

2016-12-01

Riverbed microbial communities play an oversized role in many watershed ecosystem functions, including the processing of organic carbon, cycling of nitrogen, and alterations to metal mobility. The structure and activity of microbial assemblages depend in part on geochemical conditions set by river-groundwater exchange or hyporheic exchange. To assess how seasonal changes in river-groundwater mixing affect these populations in a snowmelt-dominated fluvial system, vertical sediment and pore water profiles were sampled at three time points at one location in the hyporheic zone of the Colorado River and analyzed by using geochemical measurements, 16S rRNA gene sequencing, and ecological modeling. Oxic river water penetrated deepest into the subsurface during peak river discharge, while under base flow conditions, anoxic groundwater dominated shallower depths. Over a 70 cm thick interval, riverbed sediments were therefore exposed to seasonally fluctuating redox conditions and hosted microbial populations statistically different from those at both shallower and deeper locations. Additionally, microbial populations within this zone were shown to be the most dynamic across sampling time points, underlining the critical role that hyporheic mixing plays in constraining microbial abundances. Given such mixing effects, we anticipate that future changes in river discharge in mountainous, semiarid western U.S. watersheds may affect microbial community structure and function in riverbed environments, with potential implications for biogeochemical processes in riparian regions.

The Relationship Between Land Management, Fecal Indicator Bacteria, and the Occurrence of Campylobacter and Listeria Spp. in Water and Sediments During Synoptic Sampling In The South Fork Broad River Watershed, Northeast Georgia, U.S.A.

EPA Science Inventory

Fecal indicator bacteria (FIB) and pathogens stored in the bed sediments of streams and rivers may be mobilized into the water column affecting overall water quality. Furthermore, land management may play an important role in the concentrations of FIB and the occurrence of pathog...

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

USGS Publications Warehouse

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

2014-01-01

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

Decadal-scale Evolution of Sediment Flux in the Aulne Estuary

NASA Astrophysics Data System (ADS)

Moskalski, S. M.; Deschamps, A.; Floc'h, F.; Verney, R.; Piete, H.; Fromant, G.; Delacourt, C.

2013-12-01

Estuarine sediment transport processes have the potential to evolve over time in response to alterations in various factors both internal and external to the estuary, such as sediment supply, river discharge, tidal forcing, or changes to bathymetry. Changes in sediment transport can affect many estuarine processes (e.g. budgets of sediment-adsorbed contaminants or nutrients) and ecosystem services, such as aquaculture, primary production and the need to dredge shipping channels. Most studies of decadal-scale changes in estuaries focus on geomorphology or bathymetry, or are performed using models calibrated by a limited set of observational studies. Because of the potential for sediment flux to both affect and be affected by geomorphology and bathymetry, observational studies oriented to sediment flux evolution are needed. This study focuses on two intensive observational studies separated by 30 years to quantify change in suspended sediment concentration (SSC) in the Aulne river, a shallow macrotidal estuary in western Brittany. Moored and vessel-mounted acoustic Doppler current profilers and YSIs were deployed over a three-week period in the winter of 2013 to examine hydrodynamic and sediment transport processes. The results of the modern study were compared to a 1977 investigation of currents, suspended sediment concentration, and erosion/deposition. The 1977 study found that SSC during spring tide and average river discharge was less than 30 mg/L near the mouth and above 300 mg/L landward, with near-bottom concentrations in the turbidity maximum zone occasionally greater than 1000 mg/L. SSC was highest during low tide and remained elevated throughout, in the upstream part of the estuary. Sediment deposition was stronger after flood tide due to a longer slack period, which implies landward sediment transport in the estuary. In the 2013 study, near-bottom SSC during spring tide and average river discharge was also highest during low tide, but SSC was above 1000 mg/L for a longer duration than in 1977 and SSC decreased during low tide slack before increasing again during maximum flooding velocity. Despite strong similarities in SSC, suspended sediment fluxes near the turbidity maximum zone were stronger in the seaward direction in 2013, due to stronger and longer-duration ebbing velocities. Furthermore, fluxes were higher at the upstream observational site and lower near the mouth, indicating a high likelihood of sediment deposition in the lower estuary. The results of this study indicate that decadal-scale changes in observed sediment transport in the Aulne estuary are significant, but this conclusion will be discussed by analyzing discrepancies between data sources and quality between 1977 and 2013.

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

NASA Astrophysics Data System (ADS)

Pietroń, Jan; Jarsjö, Jerker

2014-05-01

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

Impacts of Small Scale Flow Regulation on Sediment Dynamics in an Ecologically Important Upland River

NASA Astrophysics Data System (ADS)

Quinlan, E.; Gibbins, C. N.; Batalla, R. J.; Vericat, D.

2015-03-01

Flow regulation is widely recognized as affecting fluvial processes and river ecosystems. Most impact assessments have focused on large dams and major water transfer schemes, so relatively little is known about the impacts of smaller dams, weirs and water diversions. This paper assesses sediment dynamics in an upland river (the Ehen, NW England) whose flows are regulated by a small weir and tributary diversion. The river is important ecologically due to the presence of the endangered freshwater pearl mussel Margaritifera margaritifera, a species known to be sensitive to sedimentary conditions. Fine sediment yield for the 300-m long study reach was estimated to be 0.057 t km-2 year-1, a very low value relative to other upland UK rivers. Mean in-channel storage of fine sediment was also low, estimated at an average of around 40 g m-2. Although the study period was characterized by frequent high flow events, little movement of coarser bed material was observed. Data therefore indicate an extremely stable fluvial system within the study reach. The implication of this stability for pearl mussels is discussed.

Coastal circulation and sediment dynamics in Hanalei Bay, Kaua'i, Hawaii: Part II: tracking recent fluvial sedimentation; isotope stratigraphy obtained in Summer 2005

USGS Publications Warehouse

Draut, Amy E.; Field, Michael E.; Bothner, Michael H.; Logan, Joshua B.; Casso, Michael A.; Baldwin, Sandra M.; Storlazzi, Curt D.

2006-01-01

Delivery and dispersal of fluvial sediment in Hanalei Bay, Kaua’i, Hawaii, have important implications for the health of local coral reefs. The reef community in Hanalei Bay represents a relatively healthy ecosystem. However, the reefs are periodically stressed by storm waves, and increases in sediment and dissolved substances from the Hanalei River have the potential to cause additional stress. Increased turbidity and sedimentation on corals during Hanalei River floods that occur in seasons of low wave energy, when sediment would not be readily remobilized and advected out of the bay, could affect the health and sustainability of coral reefs and the many associated species. Measurements of short-lived isotopes 7Be and 137Cs in sediment cores have been used to trace the thickness and distribution of terrestrial sediment in Hanalei Bay, in order to assess spatial and temporal patterns of sediment deposition and remobilization relative to coral-reef locations. A third isotope, 210Pb, derived primarily from seawater, provides additional information about recent sedimentary history. Isotope profiles and observations of sedimentary facies from cores collected at multiple locations in June 2005, and again in August 2005, indicate the presence of recent fluvial sediment and organic debris in the east part of the bay near the mouth of the Hanalei River. Away from the immediate vicinity of the river mouth, sediment in the uppermost 1 m below the sea floor had not retained a significant quantity of fluvial sediment within the eight months prior to either sampling effort. During the study interval in summer 2005 the Hanalei River had no major floods and there was relatively little sediment input to the bay. Sediment away from the river mouth was dominated by carbonate sand, although some terrestrial sediment was present in sub-sea-floor horizons. Sedimentary facies and isotope inventories throughout the bay showed substantial spatial heterogeneity. Sediment cores will be collected again at the same sites discussed here during early and late summer 2006. If possible, additional sites will be sampled in the Black Hole depocenter near the river mouth. Major floods in winter and spring 2006 are expected to leave a significant new sediment signal in the bay that should be detected in summer 2006.

Carbon fate in a large temperate human-impacted river system: Focus on benthic dynamics

NASA Astrophysics Data System (ADS)

Vilmin, Lauriane; Flipo, Nicolas; Escoffier, Nicolas; Rocher, Vincent; Groleau, Alexis

2016-07-01

Fluvial networks play an important role in regional and global carbon (C) budgets. The Seine River, from the Paris urban area to the entrance of its estuary (220 km), is studied here as an example of a large human-impacted river system subject to temperate climatic conditions. We assess organic C (OC) budgets upstream and downstream from one of the world's largest wastewater treatment plants and for different hydrological conditions using a hydrobiogeochemical model. The fine representation of sediment accumulation on the river bed allows for the quantification of pelagic and benthic effects on OC export toward the estuary and on river metabolism (i.e., net CO2 production). OC export is significantly affected by benthic dynamics during the driest periods, when 25% of the inputs to the system is transformed or stored in the sediment layer. Benthic processes also substantially affect river metabolism under any hydrological condition. On average, benthic respiration accounts for one third of the total river respiration along the studied stretch (0.27 out of 0.86 g C m-2 d-1). Even though the importance of benthic processes was already acknowledged by the scientific community for headwater streams, these results stress the major influence of benthic dynamics, and thus of physical processes such as sedimentation and resuspension, on C cycling in downstream river systems. It opens the door to new developments in the quantification of C emissions by global models, whereby biogeochemical processing and benthic dynamics should be taken into account.

Turbulent forces within river plumes affect spread

NASA Astrophysics Data System (ADS)

Bhattacharya, Atreyee

2012-08-01

When rivers drain into oceans through narrow mouths, hydraulic forces squeeze the river water into buoyant plumes that are clearly visible in satellite images. Worldwide, river plumes not only disperse freshwater, sediments, and nutrients but also spread pollutants and organisms from estuaries into the open ocean. In the United States, the Columbia River—the largest river by volume draining into the Pacific Ocean from North America—generates a plume at its mouth that transports juvenile salmon and other fish into the ocean. Clearly, the behavior and spread of river plumes, such as the Columbia River plume, affect the nation's fishing industry as well as the global economy.

Summary of biological investigations relating to surface-water quality in the Kentucky River basin, Kentucky

USGS Publications Warehouse

Bradfield, A.D.; Porter, S.D.

1990-01-01

The Kentucky River basin, an area of approximately 7,000 sq mi, is divided into five hydrologic units that drain parts of three physiographic regions. Data on aquatic biological resources were collected and reviewed to assess conditions in the major streams for which data were available. The North, Middle, and South Forks of the Kentucky River are in the Eastern Coal Field physiographic region. Streams in this region are affected by drainage from coal mines and oil and gas operations, and many support only tolerant biotic stream forms. The Kentucky River from the confluence of the three forks to the Red River, is in the Knobs physiographic region. Oil and gas production operations and point discharges from municipalities have affected many streams in this region. The Red River, a Kentucky Wild River, supported a unique flora and fauna but accelerated sedimentation has eliminated many species of mussels. The Millers Creek drainage is affected by brines discharged from oil and gas operations, and some reaches support only halophilic algae and a few fish. The Kentucky River from the Red River to the Ohio River is in the Bluegrass physiographic region. Heavy sediment loads and sewage effluent from urban centers have limited the aquatic biota in this region. Silver Creek and South Elkhorn Creek have been particularly affected and aquatic communities in these streams are dominated by organisms tolerant of low dissolved oxygen concentrations. Biological data for other streams indicate that habitat and water quality conditions are favorable for most commonly occurring aquatic organisms. (USGS)

Organic matter dynamics and stable isotope signature as tracers of the sources of suspended sediment

NASA Astrophysics Data System (ADS)

Schindler Wildhaber, Y.; Liechti, R.; Alewell, C.

2012-06-01

Suspended sediment (SS) and organic matter in rivers can harm brown trout Salmo trutta by affecting the health and fitness of free swimming fish and by causing siltation of the riverbed. The temporal and spatial dynamics of sediment, carbon (C), and nitrogen (N) during the brown trout spawning season in a small river of the Swiss Plateau were assessed and C isotopes as well as the C/N atomic ratio were used to distinguish autochthonous and allochthonous sources of organic matter in SS loads. The visual basic program IsoSource with 13Ctot and 15N as input isotopes was used to quantify the temporal and spatial sources of SS. Organic matter concentrations in the infiltrated and suspended sediment were highest during low flow periods with small sediment loads and lowest during high flow periods with high sediment loads. Peak values in nitrate and dissolved organic C were measured during high flow and high rainfall, probably due to leaching from pasture and arable land. The organic matter was of allochthonous sources as indicated by the C/N atomic ratio and δ13Corg. Organic matter in SS increased from up- to downstream due to an increase of pasture and arable land downstream of the river. The mean fraction of SS originating from upper watershed riverbed sediment decreased from up to downstream and increased during high flow at all measuring sites along the course of the river. During base flow conditions, the major sources of SS are pasture, forest and arable land. The latter increased during rainy and warmer winter periods, most likely because both triggered snow melt and thus erosion. The measured increase in DOC and nitrate concentrations during high flow support these modeling results. Enhanced soil erosion processes on pasture and arable land are expected with increasing heavy rain events and less snow during winter seasons due to climate change. Consequently, SS and organic matter in the river will increase, which will possibly affect brown trout negatively.

Gully annealing by fluvially-sourced Aeolian sand: remote sensing investigations of connectivity along the Fluvial-Aeolian-hillslope continuum on the Colorado River

USGS Publications Warehouse

Sankey, Joel B.; East, Amy E.; Collins, Brian D.; Caster, Joshua J.

2015-01-01

Processes contributing to development of ephemeral gully channels are of great importance to landscapes worldwide, and particularly in dryland regions where soil loss and land degradation from gully erosion pose long-term, land-management problems. Whereas gully formation has been relatively well studied, much less is known of the processes that anneal gullies and impede their growth. This work investigates gully annealing by aeolian sediment, along the Colorado River downstream of Glen Canyon Dam in Glen, Marble, and Grand Canyons, Arizona, USA (Figure 1). In this segment of the Colorado River, gully erosion potentially affects the stability and preservation of archaeological sites that are located within valley margins. Gully erosion occurs as a function of ephemeral, rainfall-induced overland flow associated with intense episodes of seasonal precipitation. Measurements of sediment transport and topographic change have demonstrated that fluvial sand in some locations is transported inland and upslope by aeolian processes to areas affected by gully erosion, and aeolian sediment activity can be locally effective at counteracting gully erosion (Draut, 2012; Collins and others, 2009, 2012; Sankey and Draut, 2014). The degree to which specific locations are affected by upslope wind redistribution of sand from active channel sandbars to higher elevation valley margins is termed “connectivity”. Connectivity is controlled spatially throughout the river by (1) the presence of upwind sources of fluvial sand within the contemporary active river channel (e.g., sandbars), and (2) bio-physical barriers that include vegetation and topography that might impede aeolian sediment transport. The primary hypothesis of this work is that high degrees of connectivity lead to less gullying potential.

Unraveling the effects of climate change and flow abstraction on an aggrading Alpine river

NASA Astrophysics Data System (ADS)

Bakker, Maarten; Costa, Anna; Adriao Silva, Tiago A.; Stutenbecker, Laura; Girardclos, Stéphanie; Loizeau, Jean-Luc; Molnar, Peter; Schlunegger, Fritz; Lane, Stuart N.

2017-04-01

Widespread temperature increase has been observed in the Swiss Alps and is most pronounced at high elevations. Alpine rivers are very susceptible to such change where large amounts of sediments are released from melting (peri)glacial environments and potentially become available for transport. These rivers are also impacted on a large scale by hydropower exploitation, where flow is commonly abstracted and transferred to a hydropower scheme. Whilst water is diverted, sediment is trapped at the intake and intermittently flushed down the river during short duration purges. Thus, these rivers are impacted upon by both climate and human forcing. In this study we quantify their relative and combined impacts upon the morphological evolution of an aggrading Alpine river. Our study focusses on the development of a sequence of braided reaches of the Borgne River (tributary of the Rhône) in south-west Switzerland. A unique dataset forms the basis for determining sediment deposition and transfer: (1) a set of high resolution Digital Elevation Models (DEMs) of the reaches was derived through applying Structure from Motion (SfM) photogrammetry to archival aerial photographs available for the period 1959-2014; (2) flow intake management data, provided by Grande Dixence SA, allowed the reconstruction of (up- and downstream) discharge and sediment supply since 1977. Subsequently we used climate data and transport capacity calculations to assess their relative impact on the system evolution over the last 25 years. Not surprisingly, considerable aggradation of the river bed (up to 5 meters) has taken place since the onset of flow abstraction in 1963: the abstraction of flow has substantially reduced sediment transport capacity whilst the sediment supply to the river was maintained. Although there was an initial response of the system to the start of abstraction in the 1960s, it was not before the onset of glacial retreat and the dry and warm years in the late 1980s and early 1990's that sediment supply increased and extensive sedimentation took place. The river reaches showed a common, synchronous development, steepening in response to altered flow sediment supply conditions. In the years thereafter sedimentation rates decreased (locally incision occurred) and the reaches showed a more phased and sequential development that propagated in the downstream direction. Besides being conditioned by variations in upstream sediment supply, sediment transfer was also affected by changes in the timing and duration of purges, associated with the management and capacity hydropower system, and the evolving river bed morphology (and local river engineering). In the Borgne River we find that despite the considerable impact of flow abstraction, it is still possible to identify a climate change signal that propagates through the system and drives river morphological response. This signal is associated with a critical climate control upon upstream sediment supply coupled with the effects of combined climate and human impact on the operation of the hydroelectric power scheme.

The fate of arsenic in a river acidified by volcanic activity and an acid thermal water and sedimentation mechanism.

PubMed

Ogawa, Yasumasa; Yamada, Ryoichi; Shinoda, Kozo; Inoue, Chihiro; Tsuchiya, Noriyoshi

2014-01-01

The Shozu-gawa river, located in the Aomori Prefecture, northern Japan, is affected by volcanic activities and acid thermal waters. The river is unique because both solid arsenic (As; as orpiment, As2S3) and dissolved As are supplied to the river from the uppermost caldera lake (Usori-ko Lake) and thermal ponds. The watershed is an excellent site for investigating the fate of different As species in a fluvial system. Upstream sediments near the caldera lake and geothermal ponds are highly contaminated by orpiment. This solid phase is transported as far as the mouth of the river. On the other hand, dissolved As is removed from the river system by hydrous ferric oxides (HFOs); however, HFO formation and removal of dissolved As do not occur in the uppermost area of the watershed, resulting in further downstream transport of dissolved As. Consequently, upstream river sediments are enriched in orpiment, whereas As(v), which is associated with HFOs in river sediments, increases downstream. Furthermore, orpiment particles are larger, and possibly heavier, than those of HFO with sorbed As. Fractionation between different chemical states of As during transport in the Shozu-gawa river is facilitated not only by chemical processes (i.e., sorption of dissolved As by HFOs), but also by physical factors (i.e., gravity). In contrast to acid mine drainage (AMD), in some areas of the Shozu-gawa river, both solid forms of As (as sulfide minerals) and dissolved As are introduced into the aquatic system. Considering that the stabilities of sulfide minerals are rather different from those of oxides and hydroxides, river sediments contacted with thermal waters possibly act as sources of As under both aerobic and anaerobic conditions.

The fluvial sediment budget of a dammed river (upper Muga, southern Pyrenees)

NASA Astrophysics Data System (ADS)

Piqué, G.; Batalla, R. J.; López, R.; Sabater, S.

2017-09-01

Many rivers in the Mediterranean region are regulated for urban and agricultural purposes. Reservoir presence and operation results in flow alteration and sediment discontinuity, altering the longitudinal structure of the fluvial system. This study presents a 3-year sediment budget of a highly dammed Mediterranean river (the Muga, southern Pyrenees), which has experienced flow regulation since the 1969 owing to a 61-hm3 reservoir. Flow discharge and suspended sediment concentration were monitored immediately upstream and downstream from the reservoir, whereas bedload transport was estimated by means of bedload formulae and estimated from regional data. Results show how the dam modifies river flow, reducing the magnitude of floods and shortening its duration. At the same time, duration of low flows increases. The downstream flow regime follows reservoir releases that are mostly driven by the irrigation needs in the lowlands. Likewise, suspended sediment and bedload transport are shown to be notably affected by the dam. Sediment transport upstream was mainly associated with floods and was therefore concentrated in short periods of time (i.e., > 90% of the sediment load occurred in < 1% of the time). Downstream from the dam, sediments were transported more constantly (i.e., 90% of the load was carried during 50% of the time). Total sediment load upstream from the dam equalled 23,074 t, while downstream it was < 1000 t. Upstream, sediment load was equally distributed between suspension and bedload (i.e., 10,278 and 12,796 t respectively), whereas suspension dominated sediment transport downstream. More than 95% of the sediments transported from the upstream basins were trapped in the reservoir, a fact that explains the sediment deficit and the river bed armouring observed downstream. Overall, the dam disrupted the natural water and sediment fluxes, generating a highly modified environment downstream. Below the dam, the whole ecosystem shifted to stable conditions owing to the reduction of water and sediment loads.

Modelling Suspended Sediment Transport in Monsoon Season: A Case Study of Pahang River Estuary, Pahang, Malaysia

NASA Astrophysics Data System (ADS)

Zakariya, Razak; Ahmad, Zuhairi; Saad, Shahbudin; Yaakop, Rosnan

2013-04-01

Sediment transport based on 2-dimensional real time model was applied to Pahang River estuary, Pahang, Malaysia and has been evaluated and verified with time series of tidal elevation, flow and suspended sediment load. Period of modelling was during highest high tide and lowest low tide in Northeast Monsoon (NE) which happened in December 2010 and Southwest Monsoon (SW) in July 2011. Simulated model outputs has been verify using Pearson's coefficient and has showed high accuracy. The validated model was used to simulate hydrodynamic and sediment transport of extreme conditions during both monsoon seasons. Based on field measurement and model simulation, tidal elevation and flow velocity, freshwater discharge of Pahang River were found to be higher during NE Monsoon. Based on the fluxes, the estuary also showed 'ebb-dominant' characteristic during highest high tide and lowest low tide in NE monsoon and normal ebbing-flooding characteristics during SW monsoon. In the Pahang River estuary, inflow and outflow patterns were perpendicular to the open boundary with circular flow formed at the shallow area in the middle of estuary during both monsoons. Referring to sea water intrusion from the river mouth, both seasons show penetration of more than 9 km (upstream input boundary) during higher high water tide. During higher lower water tide, the water intrusion stated varies which 5.6km during NE monsoon and 7.8km during SW monsoon. Regarding to the times lap during high tide, the sea water takes 2.8 hours to reach 9km upstream during NE monsoon compared to 1.9 hour during SW monsoon. The averages of suspended sediment concentration and suspended sediment load were higher during Northeast monsoon which increased the sedimentation potentials.Total of suspended sediment load discharged to the South China Sea yearly from Pahang River is approximately 96727.5 tonnes/day or 3.33 tonnes/km2/day which 442.6 tonnes/day during Northeast Monsoon and 25.3 tonnes/day during Southwest Monsoon. Thus, Pahang River estuary found to be directly affected by the monsoon factors especially due to high amount of river discharge and surface erosion from catchment areas. This study provides several useful understanding on the hydrodynamic and sediment transport of Pahang River estuary and catchment area. Keywords: Pahang River Estuary, hydrodynamic, sediment transport, MIKE21 MT

Creating an Erosion Vulnerability Map for the Columbia River Basin to Determine Reservoir Susceptibility to Sedimentation Before and After Wildfires

NASA Astrophysics Data System (ADS)

Ren, J.; Robichaud, P. J. L.; Adam, J. C.

2017-12-01

Sedimentation is important issue to most rivers and reservoirs especially in watersheds with extensive agricultural or wildfire activity. These human and natural induced disturbances have the potential to increase runoff-induced erosion and sediment load to rivers; downstream sedimentation can decrease the life expectancy of reservoir and consequently the dam. This is particularly critical in snowmelt-dominant regions because, as rising temperatures reduce snowpack as a natural reservoir, humans will become more reliant on reservoir storage. In the Northwest U.S., the Columbia River Basin (CRB) has more than 60 dams, which were built for irrigation, hydropower, and flood control, all of which are affected by sediment to varying degrees. Determining what dams are most likely to be affected by sedimentation caused by post-fire erosion is important for future management of reservoirs, especially as climate change is anticipated to exacerbate wildfire and its impacts. The objective of this study is to create a sedimentation vulnerability map for reservoirs in the CRB. There are four attributes of a watershed that determine erosion potential; soil type, topography, vegetation (such as forests, shrubs, and grasslands), and precipitation (although precipitation was excluded in this analysis). In this study, a rating system was developed on a scale of 0-90 (with 90 having the greatest erosion potential). The different layers in a Graphical Information System were combined to create an erosion vulnerability map. Results suggest that areas with agriculture have more erosion without a wildfire but that forested areas are most vulnerable to erosion rates following a fire, particularly a high severity fire. Sedimentation in dams is a growing problem that needs to be addressed especially with the likely reduction in snowpack, this vulnerability map will help determine which reservoirs in the CRB are prone to high sedimentation. This information can inform managers where post-fire erosion mitigation efforts might be prioritized.

The influence of the annual invasive plant, Impatiens glandulifera, on the sediment dynamics of inland watercourses in temperate regions

NASA Astrophysics Data System (ADS)

Dalvi, Shrutika; Greenwood, Philip

2016-04-01

Impatiens glandulifera (Common English Name - Himalayan Balsam) is a non native annual and highly invasive plant that was introduced into parts of Europe from the Himalaya during the nineteenth century as a colourful adornment to parks and gardens. This Plant colonises areas along the river banks, preferably wet, depositional sites, and displaces natural vegetation. The plant is killed by cold weather. The leaves area of riverbank previously occupied by the plant extremely vulnerable to soil erosion until new plant germinates in the following spring. Research work undertaken in the northwest Switzerland and the soutwestern United Kingdom established s link between accelerated soil erosion caused by Impatiens glandulifera and its detrimental impact on native biodiversity of riparian zone of river catchment area. This study focueses on the potential impact of such erosion on sediment quality. A priory reasoning suggests that the preference of Impatiens glandulifera on young depsotional sites near watercourses affects sediment quality. In this study, the results of a soil quality analysis along Impatiens glandulifera-contaminated river banks is presented. Soil physical and chemical properties are compared to non-affected sites to assess the potential impact of preferential erosion on water quality. In addtiion, soil surface profile (SSP) measuring based on by erosion pins, a micro profile bridge and a digital calliper at different selected locations along the riparian zone of river catchment area is used to determine erosion rates and determine sediment transfer from the riparian zone into the rivers.

Water and sediment temperatures at mussel beds in the upper Mississippi River basin

USGS Publications Warehouse

Newton, Teresa J.; Sauer, Jennifer; Karns, Byron

2013-01-01

Native freshwater mussels are in global decline and urgently need protection and conservation. Declines in the abundance and diversity of North American mussels have been attributed to human activities that cause pollution, waterquality degradation, and habitat destruction. Recent studies suggest that effects of climate change may also endanger native mussel assemblages, as many mussel species are living close to their upper thermal tolerances. Adult and juvenile mussels spend a large fraction of their lives burrowed into sediments of rivers and lakes. Our objective was to measure surface water and sediment temperatures at known mussel beds in the Upper Mississippi (UMR) and St. Croix (SCR) rivers to estimate the potential for sediments to serve as thermal refugia. Across four mussel beds in the UMR and SCR, surface waters were generally warmer than sediments in summer, and were cooler than sediments in winter. This suggests that sediments may act as a thermal buffer for mussels in these large rivers. Although the magnitude of this effect was usually <3.0°C, sediments were up to 7.5°C cooler at one site in May, suggesting site-specific variation in the ability of sediments to act as thermal buffers. Sediment temperatures in the UMR exceeded those shown to cause mortality in laboratory studies. These data suggest that elevated water temperatures resulting from global warming, thermal discharges, water extraction, and/or droughts have the potential to adversely affect native mussel assemblages.

Effect of water flux and sediment discharge of the Yangtze River on PAHs sedimentation in the estuary.

PubMed

Li, Rufeng; Feng, Chenghong; Wang, Dongxin; He, Maozhi; Hu, Lijuan; Shen, Zhenyao

2016-12-01

Historical distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) and their carriers (i.e., organic matter and mineral particles) in the sediment cores of the Yangtze Estuary were investigated, with emphasis laid on the role of the Yangtze River. Grain size component of sediments (clay, silt, and sand) and organic carbon (black carbon and total organic carbon) in the sediment cores were markedly affected by water flux and sediment discharge of the Yangtze River. Qualitative and quantitative analysis results showed that sands and black carbon acted as the main carriers of PAHs. The sedimentation of two-ring to three-ring PAHs in the estuary had significant correlations with water flux and sediment discharge of the Yangtze River. The relative lower level of the four-ring and five-ring to six-ring PAHs concentrations appeared around the year 2003 and remained for the following several years. This time period accorded well with the water impoundment time of the Three Gorges Reservoir. The decreased level of two-ring to three-ring PAHs occurred in the year 1994, and the peak points around the year 2009 indicated that PAHs sedimentation in the estuary also had close relationship to severe drought and flood in the catchments. The findings presented in this paper could provide references for assessing the impacts of water flux and sediment discharge on the historical deposition of PAHs and their carriers in the Yangtze Estuary.

Magnified Sediment Export of Small Mountainous Rivers in Taiwan: Chain Reactions from Increased Rainfall Intensity under Global Warming

PubMed Central

Lee, Tsung-Yu; Huang, Jr-Chuan; Lee, Jun-Yi; Jien, Shih-Hao; Zehetner, Franz; Kao, Shuh-Ji

2015-01-01

Fluvial sediment export from small mountainous rivers in Oceania has global biogeochemical significance affecting the turnover rate and export of terrestrial carbon, which might be speeding up at the recognized conditions of increased rainfall intensity. In this study, the historical runoff and sediment export from 16 major rivers in Taiwan are investigated and separated into an early stage (1970–1989) and a recent stage (1990–2010) to illustrate the changes of both runoff and sediment export. The mean daily sediment export from Taiwan Island in the recent stage significantly increased by >80% with subtle increase in daily runoff, indicating more sediment being delivered to the ocean per unit of runoff in the recent stage. The medians of the runoff depth and sediment yield extremes (99.0–99.9 percentiles) among the 16 rivers increased by 6.5%-37% and 62%-94%, respectively, reflecting the disproportionately magnified response of sediment export to the increased runoff. Taiwan is facing increasing event rainfall intensity which has resulted in chain reactions on magnified runoff and sediment export responses. As the globe is warming, rainfall extremes, which are proved to be temperature-dependent, very likely intensify runoff and trigger more sediment associated hazards. Such impacts might occur globally because significant increases of high-intensity precipitation have been observed not only in Taiwan but over most land areas of the globe. PMID:26372356

Trace elements and organic compounds in sediment and fish tissue from the Great Salt Lake basins, Utah, Idaho, and Wyoming, 1998-99

USGS Publications Warehouse

Waddell, Kidd M.; Giddings, Elise M.

2004-01-01

A study to determine the occurrence and distribution of trace elements, organochlorine pesticides, polychlorinated biphenyls (PCBs), and semivolatile organic compounds in sediment and in fish tissue was conducted in the Great Salt Lake Basins study unit of the National Water-Quality Assessment (NAWQA) program during 1998-99. Streambed-sediment and fish-tissue samples were collected concurrently at 11 sites and analyzed for trace-element concentration. An additional four sites were sampled for streambed sediment only and one site for fish tissue only. Organic compounds were analyzed from streambed-sediment and fish-tissue samples at 15 sites concurrently.Bed-sediment cores from lakes, reservoirs, and Farmington Bay collected by the NAWQA program in 1998 and by other researchers in 1982 were used to examine historical trends in trace-element concentration and to determine anthropogenic sources of contaminants. Cores collected in 1982 from Mirror Lake, a high-mountain reference location, showed an enrichment of arsenic, cadmium, copper, lead, tin, and zinc in the surface sediments relative to the deeper sediments, indicating that enrichment likely began after about 1900. This enrichment was attributed to atmospheric deposition during the period of metal-ore mining and smelting. A core from Echo Reservoir, in the Weber River Basin, however, showed a different pattern of trace-element concentration that was attributed to a local source. This site is located downstream from the Park City mining district, which is the most likely historical source of trace elements. Cores collected in 1998 from Farmington Bay show that the concentration of lead began to increase after 1842 and peaked during the mid-1980s and has been in decline since. Recent sediments deposited during 1996-98 indicate a 41- to 62-percent reduction since the peak in the mid-1980s.The concentration of trace elements in streambed sediment was greatest at sites that have been affected by historic mining, including sites on Little Cottonwood Creek in the Jordan River basin, Silver Creek in the Weber River basin, and the Weber River below the confluence with Silver Creek. There was significant correlation of lead concentrations in streambed sediment and fish tissue, but other trace elements did not correlate well. Streambed sediment and fish tissue collected from sites in the Bear River basin, which is predominantly rangeland and agriculture, generally had low concentrations of most elements.Sediment-quality guidelines were used to assess the relative toxicity of streambed-sediment sites to aquatic communities. Sites affected by mining exceeded the Probable Effect Concentration (PEC), the concentration at which it is likely there will be a negative effect on the aquatic community, for arsenic, cadmium, copper, lead, silver, mercury, and zinc. Sites that were not affected by mining did not exceed these criteria. Concentrations of trace elements in samples collected from the Great Salt Lake Basins study unit (GRSL) are high compared to those of samples collected nationally with the NAWQA program. Nine of 15 streambed-sediment samples and 11 of 14 fish-tissue samples had concentrations of at least one trace element greater than the concentration of 90 percent of the samples collected nationally during 1993-2000.Organic compounds that were examined in streambed sediment and fish-tissue samples also were examined in bed-sediment cores. A bed-sediment core from Farmington Bay of Great Salt Lake showed an increase in total polycyclic aromatic hydrocarbon (PAH) concentrations coincident with the increase in population in Salt Lake Valley, which drains into this bay. Analysis of streambed-sediment samples showed that the highest concentrations of PAHs were detected at urban sites, including two sites in the lower Jordan River (the Jordan River flows into Farmington Bay), the Weber River at Ogden Bay, and the Provo River near Provo. Other organic compounds detected in streambed sediment in the lower Jordan River were PCBs, DDT compounds, and chlordane compounds.Organic compounds were detected more frequently in fish tissue than in streambed sediment. Chlordane compounds and PCBs were detected more frequently at urban sites. DDT compounds were detected at 13 of 15 sites including urban and agricultural sites. Concentrations of total DDT in fish tissue exceeded the guideline for protection of fish-eating wildlife at two urban sites. The concentration of organic compounds in the GRSL study unit is low compared with that of samples collected nationally.

Linking channel hydrology with riparian wetland accretion in tidal rivers

USGS Publications Warehouse

Ensign, Scott H.; Noe, Gregory B.; Hupp, Cliff R.

2014-01-01

The hydrologic processes by which tide affects river channel and riparian morphology within the tidal freshwater zone are poorly understood, yet are fundamental to predicting the fate of coastal rivers and wetlands as sea level rises. We investigated patterns of sediment accretion in riparian wetlands along the non-tidal through oligohaline portion of two coastal plain rivers in Maryland, U.S.A., and how flow velocity, water level, and suspended sediment concentration (SSC) in the channel may have contributed to those patterns. Sediment accretion was measured over a one year period using artificial marker horizons, channel hydrology was measured over a one month period using acoustic Doppler current profilers, and SSC was predicted from acoustic backscatter. Riparian sediment accretion was lowest at the non-tidal sites (mean and standard deviation = 8 ± 8 mm yr-1), highest at the upstream tidal freshwater forested wetlands (TFFW) (33 ± 28 mm yr-1), low at the midstream TFFW (12 ± 9 mm yr-1), and high at the oligohaline (fresh-to-brackish) marshes (19 ± 8 mm yr-1). Channel maximum flood and ebb velocity was 2-fold faster at the oligohaline than tidal freshwater zone on both tidal rivers, corresponding with the differences in in-channel SSC: the oligohaline zone's SSC was more than double the tidal freshwater zone's, and was greater than historical SSC at the non-tidal gages. The tidal wave characteristics differed between rivers, leading to significantly greater in-channel SSC during floodplain inundation in the weakly convergent than the strongly convergent tidal river. Overall sediment accretion was higher in the embayed river likely due to a single storm discharge and associated sedimentation.

Post Gold King Mine Spill Investigation of Metal Stability in Water and Sediments of the Animas River Watershed.

PubMed

Rodriguez-Freire, Lucia; Avasarala, Sumant; Ali, Abdul-Mehdi S; Agnew, Diane; Hoover, Joseph H; Artyushkova, Kateryna; Latta, Drew E; Peterson, Eric J; Lewis, Johnnye; Crossey, Laura J; Brearley, Adrian J; Cerrato, José M

2016-11-01

We applied spectroscopy, microscopy, diffraction, and aqueous chemistry methods to investigate the persistence of metals in water and sediments from the Animas River 13 days after the Gold King Mine spill (August 5, 2015). The Upper Animas River watershed, located in San Juan Colorado, is heavily mineralized and impacted by acid mine drainage, with low pH water and elevated metal concentrations in sediments (108.4 ± 1.8 mg kg -1 Pb, 32.4 ± 0.5 mg kg -1 Cu, 729.6 ± 5.7 mg kg -1 Zn, and 51 314.6 ± 295.4 mg kg -1 Fe). Phosphate and nitrogen species were detected in water and sediment samples from Farmington, New Mexico, an intensive agricultural area downstream from the Animas River, while metal concentrations were low compared to those observed upstream. Solid-phase analyses of sediments suggest that Pb, Cu, and Zn are associated with metal-bearing jarosite and other minerals (e.g., clays, Fe-(oxy)hydroxides). The solubility of jarosite at near-neutral pH and biogeochemical processes occurring downstream could affect the stability of metal-bearing minerals in river sediments. This study contributes relevant information about the association of metal mixtures in a heavy mineralized semiarid region, providing a foundation to better understand long-term metal release in a public and agricultural water supply.

Level, source identification, and risk analysis of heavy metal in surface sediments from river-lake ecosystems in the Poyang Lake, China.

PubMed

Zhang, Hua; Jiang, Yinghui; Ding, Mingjun; Xie, Zhenglei

2017-09-01

The concentrations, sources, and risks of heavy metals (Fe, Al, Mn, Cr, Co, Ni, Cu, Zn, As, Cd, W, Pb, and Tl) in sediments in five river-lake ecosystems in the Poyang Lake region were studied. The concentrations of the heavy metals varied spatially, with most of the highest concentrations in the Raohe river-lake ecosystem (RH). All heavy metals except As, Cd, W, and Tl were enriched in sediments possessing high total organic carbon contents or in finer sediments. Based on enrichment factors and statistical methods, it was found that Cd in sediments in the Xiushui (XS), Ganjiang (GJ), Xinjiang (XJ) river-lake ecosystems, and RH; Mn in the XS, GJ, and RH; and W in the XS and GJ were greatly affected by anthropogenic inputs. Moreover, the origins of Cu, Zn, and As require more attention due to the high concentrations found. The high enrichment factor of Cd in the sediments indicated that this metal might cause significant pollution in the environment. The results of the modified potential ecological risk index revealed that the XS, GJ, RH, and XJ were at considerable ecological risk, while the sediments in the Fuhe river-lake ecosystem (FH) were at moderate ecological risk, with Cd contributing the highest proportion of risk. The hazard score fundamentally validated the modified potential ecological risk analysis and revealed a mean toxicity of 57.80% to the benthic organisms in the RH.

Occurrence and accumulation of pesticides and organic contaminants in river sediment, water and clam tissues from the San Joaquin River and tributaries, California

USGS Publications Warehouse

Pereira, W.E.; Domagalski, Joseph L.; Hostettler, F.D.; Brown, L.R.; Rapp, J.B.

1996-01-01

A study was conducted in 1992 to assess the effects of anthropogenic activities and land use on the water quality of the San Joaquin River and its major tributaries. This study focused on pesticides and organic contaminants, looking at distributions of contaminants in water, bed and suspended sediment, and the bivalve Corbicula fluminea. Results indicated that this river system is affected by agricultural practices and urban runoff. Sediments from Dry Creek contained elevated concentrations of polycyclic aromatic hydrocarbons (PAHs), possibly derived from urban runoff from the city of Modesto; suspended sediments contained elevated amounts of chlordane. Trace levels of triazine herbicides atrazine and simazine were present in water at most sites. Sediments, water, and bivalves from Orestimba Creek, a westside tributary draining agricultural areas, contained the greatest levels of DDT (1,1,1-trichloro-2-2-bis[p-chlorophenyl]ethane), and its degradates DDD (1,1-dichloro-2,2-bis[p-chlorophenyl]ethane), and DDE (1,1-dichloro-2,2- bis[p-chlorophenyl]ethylene). Sediment adsorption co efficients (K(oc)), and bioconcentration factors (BCF) in Corbicula of DDT, DDD, and DDE at Orestimba Creek were greater than predicted values. Streams of the western San Joaquin Valley can potentially transport significant amounts of chlorinated pesticides to the San Joaquin River, the delta, and San Francisco Bay. Organochlorine compounds accumulate in bivalves and sediment and may pose a problem to other biotic species in this watershed.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Assessment of sedimentation affecting riverine ports in Louisiana : [research project capsule].

DOT National Transportation Integrated Search

2015-04-01

The Louisiana Department of Transportation and Development (DOTD) was : tasked by the legislature in Senate Resolution 105 to study solutions to the buildup of sediment at Louisiana ports along the Mississippi River and to consult with : the Louisian...

Reconnaissance study of water quality in the mining-affected Aries River Basin, Romania

USGS Publications Warehouse

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

2008-01-01

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

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

NASA Astrophysics Data System (ADS)

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

2014-12-01

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

Modelling the impact of dam removal on geomorphic channel response and sediment delivery: an Austrian case study

NASA Astrophysics Data System (ADS)

Pöppl, Ronald; Coulthard, Tom; Keesstra, Saskia; Keiler, Margreth

2015-04-01

Dams are often considered to have the most significant impact on rivers as dam construction generally reduces downstream sediment fluxes which further involves geomorphic changes in the affected river reaches. Since many dams no longer fulfill their intended purpose (e.g. due to siltation), are dangerous (e.g. catastrophic dam failures) and/or are ecologically damaging (e.g. habitat destruction), within the last two decades several dams have been removed and many more are already proposed for removal. Unfortunately, there is still only little empirical knowledge about the geomorphic consequences of dam removals and the related sediment release which represents a big challenge for river management. Modelling is one way to approach this problem. In the presented study we modelled the impacts of dam removal on geomorphic channel processes, channel morphology and sediment delivery further considering the role of channel engineering measures and reservoir excavation within a river reach impacted by a series of dams using the landscape evolution model CAESAR-Lisflood. The model was run with data from a small catchment located in Lower Austria. Modelled geomorphic channel changes and sediment fluxes were spatio-temporally analyzed, related to real-world data and are discussed in the context of river management issues.

Fluvial-aeolian interactions in sediment routing and sedimentary signal buffering: an example from the Indus Basin and Thar Desert

USGS Publications Warehouse

East, Amy E.; Clift, Peter D.; Carter, Andrew; Alizai, Anwar; VanLaningham, Sam

2015-01-01

Sediment production and its subsequent preservation in the marine stratigraphic record offshore of large rivers are linked by complex sediment-transfer systems. To interpret the stratigraphic record it is critical to understand how environmental signals transfer from sedimentary source regions to depositional sinks, and in particular to understand the role of buffering in obscuring climatic or tectonic signals. In dryland regions, signal buffering can include sediment cycling through linked fluvial and eolian systems. We investigate sediment-routing connectivity between the Indus River and the Thar Desert, where fluvial and eolian systems exchanged sediment over large spatial scales (hundreds of kilometers). Summer monsoon winds recycle sediment from the lower Indus River and delta northeastward, i.e., downwind and upstream, into the desert. Far-field eolian recycling of Indus sediment is important enough to control sediment provenance at the downwind end of the desert substantially, although the proportion of Indus sediment of various ages varies regionally within the desert; dune sands in the northwestern Thar Desert resemble the Late Holocene–Recent Indus delta, requiring short transport and reworking times. On smaller spatial scales (1–10 m) along fluvial channels in the northern Thar Desert, there is also stratigraphic evidence of fluvial and eolian sediment reworking from local rivers. In terms of sediment volume, we estimate that the Thar Desert could be a more substantial sedimentary store than all other known buffer regions in the Indus basin combined. Thus, since the mid-Holocene, when the desert expanded as the summer monsoon rainfall decreased, fluvial-eolian recycling has been an important but little recognized process buffering sediment flux to the ocean. Similar fluvial-eolian connectivity likely also affects sediment routing and signal transfer in other dryland regions globally.

The distribution and partitioning of common antibiotics in water and sediment of the Pearl River Estuary, South China.

PubMed

Liang, Ximei; Chen, Baowei; Nie, Xiangping; Shi, Zhen; Huang, Xiaoping; Li, Xiangdong

2013-09-01

Antibiotics released into the aquatic environment play an important role in the spread of antibiotic resistance. In the Pearl River Estuary (PRE) and the coastal zone, the concentrations of antibiotics decreased from the Pearl River to the estuary, suggesting that antibiotics primarily originated from river tributaries and terrigenous sources. Within the PRE area, the concentrations of antibiotics in water were higher in the west coast than the east side, reflecting the high density of anthropogenic activities and hydraulic conditions along the west riverbank. Seasonal variations were also observed for most of detected antibiotics in water. The pseudo-partitioning coefficient of norfloxacin had a good correlation with the TOC content of sediments, as did erythromycin-H2O with the pH of water. The results suggest that environmental conditions can significantly affect the distribution of antibiotics between water and sediment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Definition of a mobilizing volume of sediment in a valley interested by volcanic eruption: Rio Blanco valley (Chile)

NASA Astrophysics Data System (ADS)

Oss-Cazzador, Daniele; Iroumé, Andrés; Picco, Lorenzo

2016-04-01

Volcanic explosive activity can strongly affect the riverine environments. Deposition of tephra, pyroclastic and hyperconcentrated flows along both the valley bottom and hillslopes can radically change the environmental morphology. Accumulation and transport of pyroclastic material can increase hazards and risks for anthropic activities. The aims of this research are to evaluate and quantify the amount of erodible sediment that can be transported along a gravel bed river affected by a volcanic eruption. The Rio Blanco valley (Chile) was upset by the plinian-type eruption of Chaiten volcano in 2008. The great amount of tephra released in the initial phase and the subsequent pyroclastic flows, accumulated up to 8 m of sediment over a great portion of the Rio Blanco valley. Using aerial photographs was possible to define the extension of vegetated zones affected by the eruption. The area was interested by a high mortality of vegetation, as confirmed by field surveys. Dendrometric measurements permitted to quantify the volume of wood and observe that renewal and herbal layer are almost absent, determining low soil cohesion and easier erosion by superficial and river erosion processes. Analysis of sediment accumulation allowed quantifying the volume of sediment that can be transported downstream. The analyses were carried out considering 7 km-long a reach, from the river mouth to the confluence between Caldera creek and Rio Blanco. After the eruption, was possible to define as a total area of about 2.19 km2 was affected by tephra deposition, the 40% (0,87 km2) was eroded by flows, while 60% (1,32 km2) is still present and composed by tephra, buried large wood (LW) and dead standing trees. Considering an average high of 5 m, the potential erodible sediment is around 6,5 x 106 m3, moreover there is a potential amount of about 7,3 x 104 m3 of LW that can be transported towards mouth. These analyses can be useful to better define the management plan for the river delta. In fact, in this area there is the Chaiten port, a fundamental structure for the human activities. These results can permit to better define the dragging activities and sediment abstraction. This research is funded within the Department of TESAF, University of Padua (Italy), and Chilean research Project FONDECYT 1141064 "Effects of vegetation on channel morphodynamics: a multiscale investigation in Chilean gravel-bed rivers".

[Characteristics of heavy metal elements and their relationship with magnetic properties of river sediment from urban area in Lanzhou].

PubMed

Wang, Bo; Zhao, Shuang; Xia, Dun-sheng; Yu, Ye; Tian, Shi-li; Jia, Jia; Jiang, Xiao-rong

2011-05-01

The contents of As, Co, Cr, Cu, Ni, Pb, V and Zn in the surface sediments from 8 rivers in urban area in Lanzhou were monitored by ecological risk which was assessed by the potential ecological Håkanson index, and the index of geoaccumulation (Igeo), sediment enrichment factor (R), and environmental magnetism. The results showed that: (1) the potential ecological risk of heavy metals of As, Co, Ni, V in surface sediments from 8 rivers were low, which belonged to low ecological risk. But the risk of heave metals Cr, Pb, Zn in surface sediments from Yuer river was high, which belonged to middle ecological risk, and in downstream of Yuer river, the element of Cu belonged to high ecological risk. (2) The rivers in Lanzhou could be divided into four groups according to the heavy mental pollution degree: first type, such as Paihong river, Shier river, Yuer river and Shuimo river, called downstream concentrate type; second type, such as Qili river, called upstream concentrate type; third type, such as Luoguo river and Dasha river, called less affected type; fourth type, Lanni river, which polluted heavily in up and downstream; (3) The correlation analysis between magnetic parameters and element contents show that the parameters which mainly reflect the concentration of the magnetic minerals (X, SIRM, Ms) have close association with Cr, Ni, Pb, Zn, Cu, So we can infer that the magnetic minerals in deposits samples mainly came from electroplating effluent, motor vehicle emission, and domestic sewage. SIRM/X shows a strong correlation with Cr, Ni, Pb, Zn, indicating the distribution of anthropogenic particulates. (4) The magnetic minerals(X, SIRM, Ms) have a strong correlation with the geoaccumulation (Igeo) than potential ecological risk index and enrichment factor (R). These results suggest a possible approach for source identification of magnetic material in pollution studies and the validity of using magnetic measurements to mapping the polluted area.

A hydromorphological framework for the evaluation of e-flows

NASA Astrophysics Data System (ADS)

Bussettini, Martina; Rinaldi, Massimo; Grant, Gordon

2017-04-01

Anthropogenic alteration of hydromorphological processes in rivers is a major factor that diminishes river health and undermines environmental objectives envisaged by river protection policies. Specifying environmental flows to address those impacts can be a key strategy for the maintenance of functional river processes and the achievement of those objectives. Environmental flows are determined by various methods and approaches, based primarily on hydrological and/or hydraulic evaluations, although holistic methodologies, considering the many interacting factors that structure aquatic ecosystems, including sediments, are increasingly used. Hydrological and geomorphological processes are highly coupled and any change in one typically affects the other. The coupling varies over different spatial and temporal scales, and changing either hydrological or geomorphological processes can result in alteration of river habitats, ultimately impacting ecological processes. In spite of these linkages, current restoration approaches typically focus only on changes on hydrological regime as a means promoting ecological enhancements. Neglecting sediment transport and its interaction with flow in shaping riverine habitats is likely to results not only in minor or no enhancements in the ecology, but may also increase the costs of water use. A more integrated view of how human activities jointly affect sediment regime, river morphology and river flows is therefore needed in order to determine the most effective actions to rehabilitate river processes to desired states. These states involve considerations of the combination of intrinsic ("natural") conditions (e.g. river sensitivity and morphological potential, off-site conditions) and socio-economic constraints. The evaluation of such factors, the analysis of different scenarios, and the selection of appropriate actions require the contextualization of river reaches within a wider spatial-temporal hydromorphological framework. Here we present such a general multiscale, process-based hydromorphological framework, and discuss its application to the problem of how best to analyse and estimate e-flows.

Carbon Transport, Transformation and Retention in Tropical Systems: The Lower Tana River Corridor as a Natural Laboratory

NASA Astrophysics Data System (ADS)

Govers, G.; Omengo, F.; Geeraert, N.; Bouillon, S.; Neyens, G.

2016-12-01

The lower Tana river in Kenya is an active river carrying high sediment and carbon loads, while lateral influxes from tributaries are very limited. We used this river as a natural laboratory to study the dynamics of carbon in the river-floodplain system. We measured carbon fluxes in the river as well as rates of carbon processing. Furthermore, we assessed carbon deposition in the floodplain and carbon mobilisation by river migration. We show that both within-river carbon dynamics as well as river-floodplain interaction can only be understood by accounting for autogenic river processes: the amounts of sediment (5-6 Mt yr-1) and particulate organic carbon (120-180 Mg yr-1) that are re-mobilised within the river reach (300 km) are similar to the amounts the reach receives from upstream. Carbon and sediment mobilisation are compensated for by deposition, both in the floodplain and within the river (point bars). This intensive exchange explains why the suspended sediment in the Tana river becomes finer (and more enriched in carbon) in the downstream direction, despite the deposition of fine, carbon-rich sediments in the floodplain. Contrary to what is found in temperate floodplains, overall carbon burial appears not to be very effective: most buried carbon is mineralised within decades after burial. However, burial efficiency is much higher for allochthonous organic carbon (deposited by the river) than for autochthonous organic carbon (sourced from local primary production). The Tana river does not only exchange carbon with its floodplain through deposition and remobilisation of POC. When floods occur, the floodplain acts as an important source of dissolved organic and inorganic carbon which is not only produced by organic carbon decomposition but also by weathering. Finally, there is significant CO2 outgassing from the Tana river, releasing 3-5 Mg C yr-1 to the atmosphere. Our study highlights the role of tropical river corridors as highly dynamic environments, which may be strongly affected by human management and/or climatic change. The planned construction of a major dam in the upper Tana is likely to steady the river's discharge and will limit lateral river migration and flooding, which may transform the lower Tana from a net sediment (and to a lesser extent, carbon) sink to a source.

Assessment of heavy metal contamination in the sediment of the River Ghaghara, a major tributary of the River Ganga in Northern India

NASA Astrophysics Data System (ADS)

Singh, Harendra; Pandey, Ruby; Singh, Sudhir Kumar; Shukla, D. N.

2017-11-01

The present study includes a systematic analysis of sediment contamination by heavy metals of the River Ghaghara flowing through the Uttar Pradesh and Bihar in Indian Territory. To estimate the geochemical environment of the river, seven heavy metals, namely Co, Cu, Cr, Ni, Cd, Zn, and Pb were examined from the freshly deposited river bed sediment. All the sediment samples were collected on a seasonal basis for the assessment of fluctuation in 2014-2015 and after preparation samples were analyzed using standard procedure. Result showed that heavy metal concentration ranged between 11.37 and 18.42 mg/kg for Co, 2.76 and 11.74 mg/kg for Cu, 61.25 and 87.68 mg/kg for Cr, 15.29 and 25.59 mg/kg for Ni, 0.21 and 0.28 mg/kg for Cd, 13.26 and 17.59 mg/kg for Zn, 10.71 and 14.26 mg/kg for Pb in different season. Metal contamination factor indicates the anthropogenic input in the river sediment was in the range of (0.62-0.97) for Co, (0.04-0.26) for Cu, (0.68-0.97) for Cr, (0.22-0.38) for Ni, (0.70-0.93) for Cd, (0.14-0.19) for Zn, and (0.54-0.71) for Pb. The highest contamination degree of the sediment was noticed as 4.01 at Ayodhya and lowest as 3.16 at Katerniaghat. Geo-accumulation index was noted between (0 and 1) which showed that sediment was uncontaminated to moderately contaminated and may have adverse affects on freshwater ecology of the river. Pollution load index (PLI) was found highest at Chhapra which was 0.45 and lowest at Katerniaghat which was 0.35 and it indicates that the river sediment has a low level of contamination. Significant high correlation was observed between Co, Cu, and Zn, it suggests same source of contamination input is mainly due to human settlement and agriculture activity. Positive correlation between Zn, Co, Cu, Cr, and Ni indicated a natural origin of these elements in the river sediment. Cluster analysis suggests grouping of similar polluted sites. The strong similarity between Co, Zn, Pb, Ni, Cu, and Cd showed relationship of these metals come from the same origin, which is possibly from natural and anthropogenic input which was also confirmed by correlation analysis. Using the various pollution indicators it was found that the river bed sediment is less contaminated by toxic metals during the study but the sediment quality may degrade in the near future due to increasing anthropogenic inputs in the river basin, hence proper management strategies are required to control the direct dumping of wastewater in the river.

Spatial and temporal variability in sedimentation rates associated with cutoff channel infill deposits: Ain River, France

USGS Publications Warehouse

Piégay, H.; Hupp, C.R.; Citterio, A.; Dufour, S.; Moulin, B.; Walling, D.E.

2008-01-01

Floodplain development is associated with lateral accretion along stable channel geometry. Along shifting rivers, the floodplain sedimentation is more complex because of changes in channel position but also cutoff channel presence, which exhibit specific overflow patterns. In this contribution, the spatial and temporal variability of sedimentation rates in cutoff channel infill deposits is related to channel changes of a shifting gravel bed river (Ain River, France). The sedimentation rates estimated from dendrogeomorphic analysis are compared between and within 14 cutoff channel infills. Detailed analyses along a single channel infill are performed to assess changes in the sedimentation rates through time by analyzing activity profiles of the fallout radionuclides 137Cs and unsupported 210Pb. Sedimentation rates are also compared within the channel infills with rates in other plots located in the adjacent floodplain. Sedimentation rates range between 0.65 and 2.4 cm a−1 over a period of 10 to 40 years. The data provide additional information on the role of distance from the bank, overbank flow frequency, and channel geometry in controlling the sedimentation rate. Channel infills, lower than adjacent floodplains, exhibit higher sedimentation rates and convey overbank sediment farther away within the floodplain. Additionally, channel degradation, aggradation, and bank erosion, which reduce or increase the distance between the main channel and the cutoff channel aquatic zone, affect local overbank flow magnitude and frequency and therefore sedimentation rates, thereby creating a complex mosaic of sedimentation zones within the floodplain and along the cutoff channel infills. Last, the dendrogeomorphic and 137Cs approaches are cross validated for estimating the sedimentation rate within a channel infill.

Is mercury from small-scale gold mining prevalent in the southeastern Peruvian Amazon?

PubMed

Moreno-Brush, Mónica; Rydberg, Johan; Gamboa, Nadia; Storch, Ilse; Biester, Harald

2016-11-01

There is an ongoing debate on the fate of mercury (Hg) in areas affected by artisanal and small-scale gold mining (ASGM). Over the last 30 years, ASGM has released 69 tons of Hg into the southeastern Peruvian Amazon. To investigate the role of suspended matter and hydrological factors on the fate of ASGM-Hg, we analysed riverbank sediments and suspended matter along the partially ASGM-affected Malinowski-Tambopata river system and examined Hg accumulation in fish. In addition, local impacts of atmospheric Hg emissions on aquatic systems were assessed by analysing a sediment core from an oxbow lake. Hg concentrations in riverbank sediments are lower (20-53 ng g -1 ) than in suspended matter (∼400-4000 ng g -1 ) due to differences in particle size. Elevated Hg concentrations in suspended matter from ASGM-affected river sections (∼1400 vs. ∼30-120 ng L -1 in unaffected sections) are mainly driven by the increased amount of suspended matter rather than increased Hg concentrations in the suspended matter. The oxbow lake sediment record shows low Hg concentrations (64-86 ng g -1 ) without evidence of any ASGM-related increase in atmospheric Hg input. Hg flux variations are mostly an effect of variations in sediment accumulation rates. Moreover, only 5% of the analysed fish (only piscivores) exceed WHO recommendations for human consumption (500 ng g -1 ). Our findings show that ASGM-affected river sections in the Malinowski-Tambopata system do not exhibit increased Hg accumulation, indicating that the released Hg is either retained at the spill site or transported to areas farther away from the ASGM areas. We suspect that the fate of ASGM-Hg in such tropical rivers is mainly linked to transport associated with the suspended matter, especially during high water situations. We assume that our findings are typical for ASGM-affected areas in tropical regions and could explain why aquatic systems in such ASGM regions often show comparatively modest enrichment in Hg levels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Niger River Discharge and the Connection to the West African Monsoon Over the Last 25 kyr

NASA Astrophysics Data System (ADS)

Patten, J.; Marcantonio, F.; Slowey, N. C.; Schmidt, M. W.; Parker, A. O.; Thomas, D. J.

2016-12-01

The intensity of the West African monsoon is directly tied to the shifting of the Inter-Tropical Convergence Zone and global-scale climate variability. As the West African monsoon varies through time, it affects the precipitation that occurs within the Niger River basin and the Niger River's discharge into the eastern equatorial Atlantic Ocean. The accumulation of marine sediments on the continental slope offshore of the Niger Delta reflects these processes. We seek to better understand how related environmental processes have varied as climate and sea level changed during the latter part of the last glacial-interglacial cycle. Here we present results from our ongoing investigation of sediments collected offshore of the Niger Delta that reflect such changes. The concentrations of 230Th, 232Th, and 234U in the sediments have been measured and combined with ages from radiocarbon dates and planktonic foraminiferal δ18O stratigraphies to estimate how the rate of sediment accumulation has varied through time. This record is considered together with measurements of sediment CaCO3 content and grain-size distribution to better understand the relative importance of environmental processes that control the flux of sediments and thorium to the seafloor - scavenging by particles settling through the water column versus the transport of sediments downslope by turbidity flows. We present xs230Th-derived 232Th fluxes that we suggest approximate the amount of fine-grained detrital material delivered from the Niger River to our sites. We anticipate that the importance of these competing processes will vary as climate/sea-level change influences the flux of sediments from the Niger River and the transport of these sediments to the slope.

The abiotic environment of the interstitial of a small Swiss river in the foothills of the Alps and its influence on gravel spawning brown trout (Salmo trutta L.)

NASA Astrophysics Data System (ADS)

Schindler, Yael; Michel, Christian; Holm, Patricia; Alewell, Christine

2010-05-01

The hyporheic zone can be characterized by multiple abiotic parameters (e.g. bulk density, texture, temperature, oxygen, ammonium, nitrate) which are all influenced directly or indirectly by the exchange processes between surface water and groundwater. These processes can vary both in time and space and are mainly driven by river discharge, ground water level and flow patterns. The input of fine sediment particles can change water-riverbed interactions through river bed clogging potentially affecting the embryonal development and survival of gravel spawning fish, such as brown trout (Salmo trutta L.). With our investigations we aim to understand these complex interactions spatially and temporally on a relevant small scale, i.e. within individual artificial brown trout redds. We designed an experimental field setup to directly investigate i) the influence of the abiotic river and redd environment on brown trout embryo development and ii) the hydrological dynamics affecting the abiotic environment in artificial brown trout. Additionally, our setup allows investigating the temporal dynamics of i) fine-sediment infiltration into the artificial redds and ii) embryo survival to two distinct developmental stages (i.e. eyed stage and hatch) The experiment was conducted in three sites of a typical Swiss river (Enziwigger, Canton of Luzern) with a strongly modified morphology. Individual sites represented a high, medium and low fine-sediment load. In each site, six artificial redds (18 in total) were built and data were collected during the entire incubation phase. Redds were located in places where natural spawning of brown trout is present. We adapted multiple established methods to the smaller scale of our river to study the dynamics of the most relevant abiotic parameters potentially affecting embryo development: Oxygen content and temperature was monitored continuously in different depths, fine sediment (bedload, suspended sediment load and its input in the river bed) was measured weekly and water samples for DOC and nitrogen components analysis were collected regularly. In addition, all redds were equipped with mini piezometers to measure the hydraulic gradient through the redds. Finally, water stage and turbidity were monitored continuously. Results of the first spawning season will be presented. Dynamic of abiotic parameters and their influence on spawning of brown trout will be discussed.

Assessing the potential for change in the middle Yangtze River channel following impoundment of the Three Gorges Dam

NASA Astrophysics Data System (ADS)

Yuan, Wenhao; Yin, Daowei; Finlayson, Brian; Chen, Zhongyuan

2012-04-01

The geomorphic impacts of dams on downstream river channels are complex, not readily predictable for specific cases, but widely reported in the literature. For the Three Gorges Dam on the Yangtze (Changjiang) River in China, no studies of the impact of the changed flow and sediment conditions below the dam on the behaviour of the channel were included in the pre-dam feasibility report. We have assembled a database of flow and sediment data for the middle Yangtze River from Yichang to Hankou and used this to analyse changes following the closure of the dam. While total flow is little affected, the operating strategy for the dam that provides for storage of part of the summer high flows to maintain hydroelectric power generation in winter (the low flow season) is reflected in changes to the seasonal distribution of flow below the dam. We calculated potential sediment carrying capacity and compared it with measured sediment concentrations for both pre- and post-dam conditions. While channel sedimentation is indicated along the middle Yangtze for pre-dam conditions, scour is indicated for post-dam conditions, highest at Yichang immediately below the dam and decreasing downstream.

In situ and laboratory bioassays with Chironomus riparius larvae to assess toxicity of metal contamination in rivers: the relative toxic effect of sediment versus water contamination.

PubMed

Faria, Mafalda S; Lopes, Ricardo J; Nogueira, António J A; Soares, Amadeu M V M

2007-09-01

We used bioassays employing head capsule width and body length increase of Chironomus riparius larvae as end points to evaluate metal contamination in streams. Bioassays were performed in situ near an abandoned Portuguese goldmine in the spring of 2003 and 2004. Bioassays also were performed under laboratory conditions with water and sediment collected from each stream to verify if laboratory bioassays could detect in situ toxicity and to evaluate the relative contribution of sediment and water to overall toxicity. We used field sediments with control water and control sediments with field water to discriminate between metal contamination in water and sediment. Field water with dry and sieved, organic matter-free, and nontreated sediments was used to determine the toxicity of heavy metals that enter the organism through ingested material. In both in situ and laboratory bioassays, body length increase was significantly inhibited by metal contamination, whereas head capsule width was not affected. Body length increase was more affected by contaminated sediment compared to contaminated water. The lowest-effect level of heavy metals was observed in the dry and sieved sediment that prevented ingestion of sediment particles by larvae. These results suggest that body length increase of C. riparius larvae can be used to indicate the impact of metal contamination in rivers. Chironomus riparius larvae are more affected by heavy metals that enter the organism through ingested sediment than by heavy metals dissolved in the water column. Nevertheless, several factors, such as the particle size and organic matter of sediment, must be taken into account.

River basin affected by rare perturbation events: the Chaiten volcanic eruption.

NASA Astrophysics Data System (ADS)

Picco, Lorenzo; Iroumé, Andrés; Oss-Cazzador, Daniele; Ulloa, Hector

2017-04-01

Natural disasters can strongly and rapidly affect a wide array of environments. Among these, volcanic eruptions can exert severe impacts on the dynamic equilibrium of riverine environment. The production and subsequent mobilization of large amounts of sediment all over the river basin, can strongly affect both hydrology and sediment and large wood transport dynamics. The aim of this research is to quantify the impact of a volcanic eruption along the Blanco River basin (Southern Chile), considering the geomorphic settings, the sediment dynamics and wood transport. Moreover, an overview on the possible management strategies to reduce the risks will be proposed. The research was carried out mainly along a 2.2 km-long reach of the fourth-order Blanco stream. Almost the entire river basin was affected by the volcanic eruption, several meters of tephra (up to 8 m) were deposited, affecting the evergreen forest and the fluvial corridor. Field surveys and remote sense analysis were carried out to investigate the effect of such extreme event. A Terrestrial Laser Scanner (TLS) was used to detect the morphological changes by computing Difference of Dems (DoDs), while field surveys were carried out to detect the amount of in-channel wood; moreover aerial photos have been analyzed to detect the extension of the impact of volcanic eruption over the river basin. As expected, the DoDs analysis permitted to detect predominant erosional processes along the channel network. In fact, over 190569 m2 there was erosion that produced about 362999 m3 of sediment mobilized, while the deposition happened just over 58715 m2 for a total amount of 23957 m3. Looking then to the LW recruited and transported downstream, was possible to detect as along the active channel corridor a total amount of 113 m3/ha of wood was present. Moreover, analyzing aerial photographs taken before and after the volcanic eruption was possible to define as a total area of about 2.19 km2 was affected by tephra deposition, 0.87 km2 has already been eroded by floods, while 1.32 km2 is still there. Considering an average depth of 5 m, the potential amount of sediment erodible and potentially transported downstream during the next near future is around 6.5 x 106 m3. Finally, from the same area can be recruited other 7.3 x 104 m3 of LW that can be transported towards the mouth. These results may help to better define management strategies to reduce the potential risks to the sensitive structures and cross section downstream. In fact, the management of sediment and LW transport through the lower Chaiten village appear of fundamental importance to guarantee a safer condition. This research is funded by the Chilean research Project FONDECYT 1141064 "Effects of vegetation on channel morphodynamics: a multiscale investigation in Chilean gravel-bed rivers".

Turbidity and Total Suspended Solids on the Lower Cache River Watershed, AR.

PubMed

Rosado-Berrios, Carlos A; Bouldin, Jennifer L

2016-06-01

The Cache River Watershed (CRW) in Arkansas is part of one of the largest remaining bottomland hardwood forests in the US. Although wetlands are known to improve water quality, the Cache River is listed as impaired due to sedimentation and turbidity. This study measured turbidity and total suspended solids (TSS) in seven sites of the lower CRW; six sites were located on the Bayou DeView tributary of the Cache River. Turbidity and TSS levels ranged from 1.21 to 896 NTU, and 0.17 to 386.33 mg/L respectively and had an increasing trend over the 3-year study. However, a decreasing trend from upstream to downstream in the Bayou DeView tributary was noted. Sediment loading calculated from high precipitation events and mean TSS values indicate that contributions from the Cache River main channel was approximately 6.6 times greater than contributions from Bayou DeView. Land use surrounding this river channel affects water quality as wetlands provide a filter for sediments in the Bayou DeView channel.

Data on natural organic substances in dissolved, colloidal, suspended-silt and -clay, and bed-sediment phases in the Mississippi River and some of its tributaries, 1987-90

USGS Publications Warehouse

Leenheer, J.A.; Noyes, T.I.; Brown, P.A.

1994-01-01

The Mississippi River and some of its tributaries were sampled for natural organic substances dissolved in water and in suspended and bed sediments during seven sampling cruises from 1987-90. The sampling cruises were made during different seasons, in the free-flowing reaches of the river from St. Louis, Missouri, to New Orleans, Louisiana. The first three cruises were made during low-water conditions, and the last four cruises during high-water conditions. The purpose for sampling and characterizing natural organic substances in the various phases in the river was to provide an understanding of how these substances facilitate contaminant transport and transformations in the Mississippi River. Significant conclusions of this study were: (1) Natural organic substances appear to stabilize ' certain colloids against aggregation; therefore, these colloids remain in suspension and can act as transport agents that are not affected by sedimentation. Bacteria were found to be a significant fraction of organic colloids. (2) A new class of organic contaminants (polyethylene glycols) derived from nonionic surfactant residues was discovered dissolved with natural organic substances in water. These polyethylene glycols have the potential to affect both organic and inorganic contaminant transport in water. (3) The entire dissolved organic-matter component under varying hydrologic and seasonal conditions was characterized. (4) A method was developed to characterize organic matter in sediment by solid-state, 13C-nuclear magnetic resonance spectrometry. (5) The organic matter in suspended sediments was characterized by a variety of spectral and nonspectral methods. The protein component (significant in trace-metal binding) and lipid component (significant in organic-contaminant binding) were found to be major constituents in natural organic matter in suspended sediment. (6) Pools are reservoirs acting as traps of sedimentary organic matter of allochthonous origin and export material of autochthonous nitrogen. (7) A major portion of the mass of organic colloids in transport consisted of bacterial cells.

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

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

USGS Publications Warehouse

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

1996-01-01

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

The effect of contaminated sediments on fecundity of the brown bullhead in three Lake Erie tributaries

USGS Publications Warehouse

Lesko, Lynn T.; Smith, Stephen B.; Blouin, Marc A.

1996-01-01

Female brown bullhead (Ameiurus nebulosus) were collected from three Lake Erie tributaries (Ohio) from 8 to 25 May 1989, to determine the effects of contaminated sediments on reproductive potentials. Fish obtained from the Black and Cuyahoga rivers, which contain sediments with elevated concentrations of metals, PCBs, and PAHs, were compared with fish collected in Mud Brook, a tributary of the Huron River, which was selected as our reference site. Fecundity, egg diameter, fish length and weight, and the presence of external abnormalities were recorded for each fish. Brown bullhead from the contaminated sites were larger then those from the reference site and fecundity was significantly (P < 0.05) different in all three river systems. Those from the most polluted river (Cuyahoga River) had the greatest number of eggs per individual female. The high frequency of external abnormalities observed on brown bullhead from the contaminated sites did not appear to have a detrimental influence on fecundity. These results suggest that fecundity of the brown bullhead was not adversely affected in ecosystems altered by the presence of contaminated sediments. Increased fecundity of the brown bullhead from impacted rivers may be the result of reduced competition for an abundant invertebrate food source and limited predation by other fish species whose numbers are largely depleted in these degraded systems.

Water-quality reconnaissance of the Pascagoula and Escatawpa Rivers, Jackson County, Mississippi, May 1974 to July 1978

USGS Publications Warehouse

Faye, Robert E.

1980-01-01

Short-term, water-quality reconnaissances along the downstream reaches of the Pascagoula and Escatawpa Rivers in Jackson County , Miss., indicate that stream quality during the period May 1974 to July 1978 was affected by wastewater discharges as well as river discharge and the extent of tidal intrusion. Specific conductances on the Pascagoula River ranged from less than 100 to more than 40,000 micromhos per centimeter and increased downstream. Specific conductance also increased with depth at downstram sites, indicating density stratification. Dissolved-oxygen concentrations were also affected by density stratification but were generally greater than 4.0 milligrams per liter in both rivers. Analyses of 5-day biochemical oxygen demand and nutrient concentrations indicate that oxidation of both carbonaceous and nitrogenous materials significantly affected the waste assimilative capacity of the rivers. Concentrations of pesticides and most trace elements in both the water column and the bottom sediments were zero or very small. Titanium concentrations were less than 220 micrograms per liter in the water column and 6,500 micrograms per gram in bottom sediments. Small concentrations of oil and grease, PCB's, and phenols were also detected. Fecal coliform and fecal streptococcal bacteria concentrations were generally greater in the Escatawpa River and ranged from about 10 to 18,000 colonies per 100 milliliters of water. (USGS)

Mercury bioaccumulation assessment for the St. Louis River Area of Concern (poster)

EPA Science Inventory

Elevated mercury concentrations have been documented in fish and invertebrates within the St. Louis River Area of Concern (AOC). Mercury bioavailability is affected by multiple factors, including mercury sources, sediment and water geochemistry, food web structure, individual fis...

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

NASA Astrophysics Data System (ADS)

Wang, Jie; Wang, Hao; Ning, Shaowei; Hiroshi, Ishidaira

2018-06-01

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

Anthropogenic disruption to the seismic driving of beach ridge formation: The Sendai coast, Japan.

PubMed

Goff, James; Knight, Jasper; Sugawara, Daisuke; Terry, James P

2016-02-15

The expected geomorphic after-effects of the Mw 9.0 Tōhoku-oki earthquake of 11 March 2011 (eastern Japan) are summarized by a schematic model of seismic driving, which details seismogenic disturbances to sediment systems that affect the rate or timing of sediment delivery to coastlines over timescales of 10(2)-10(4)years. The immediate physical environmental responses to this high-magnitude earthquake included a large tsunami and extensive region-wide slope failures. Normally, slope failures within mountain catchments would have significant impacts on Japan's river and coastal geomorphology in the coming decades with, for example, a new beach ridge expected to form within 20-100 years on the Sendai Plain. However, human activity has significantly modified the rate and timing of geomorphic processes of the region, which will have impacts on likely geomorphic responses to seismic driving. For example, the rivers draining into Sendai Bay have been dammed, providing sediment traps that will efficiently capture bedload and much suspended sediment in transit through the river system. Instead of the expected ~1 km of coastal progradation and formation of a ~3m high beach ridge prior to the next large tsunami, it is likely that progradation of the Sendai Plain will continue to slow or even cease as a result of damming of river systems and capture of river sediments behind dams. The resulting reduction of fluvial sediment delivery to the coast due to modification of rivers inadvertently makes seawalls and other engineered coastal structures even more necessary than they would be otherwise. Copyright © 2015 Elsevier B.V. All rights reserved.

Evolution of Metallic Trace Elements in Contaminated River Sediments: Geochemical Variation Along River Linear and Vertical Profile

NASA Astrophysics Data System (ADS)

Kanbar, Hussein; Montarges-Pelletier, Emmanuelle; Mansuy-Huault, Laurence; Losson, Benoit; Manceau, Luc; Bauer, Allan; Bihannic, Isabelle; Gley, Renaud; El Samrani, Antoine; Kobaissi, Ahmad; Kazpard, Veronique; Villieras, Frédéric

2015-04-01

Metal pollution in riverine systems poses a serious threat that jeopardizes water and sediment quality, and hence river dwelling biota. Since those metallic pollutants can be transported for long distances via river flow, river management has become a great necessity, especially in times where industrial activities and global climate change are causing metal release and spreading (by flooding events). These changes are able to modify river hydrodynamics, and as a consequence natural physico-chemical status of different aquatic system compartments, which in turn alter metal mobility, availability and speciation. Vertical profiles of sediments hold the archive of what has been deposited for several tenths of years, thus they are used as a tool to study what had been deposited in rivers beds. The studied area lies in the Orne river, northeastern France. This river had been strongly modified physically and affected by steelmaking industrial activities that had boosted in the middle of the last century. This study focuses on several sites along the linear of the Orne river, as well as vertical profiles of sediments. Sediment cores were collected at sites where sedimentation is favoured, and in particular upstream two dams, built in the second half of the XXth century for industrial purposes. Sediment cores were sliced into 2-5cm layers, according to suitability, and analysed for physical and physico-chemical properties, elemental content and mineralogy. Data of the vertical profile in a sediment core is important to show the evolution of sediments as a function of depth, and hence age, in terms of nature, size and constituents. The physical properties include particle size distribution (PSD) and water content. In addition, the physico-chemical properties, such as pH and oxido-reduction potential (ORP) of interstitial water from undisturbed cores were also detected. Total elemental content of sediment and available ones of extracted interstitial waters was detected using ICP-MS and ICP-OES for trace and major elements respectively. Well crystallized minerals were detected by X-Ray Diffraction (XRD), while amorphous and poorly crystallized phases were identified with scanning and transmission electron microscope (SEM and TEM respectively), combined with Energy Dispersive X-Ray Spectroscopy (EDXS). Such microscopic techniques also provided information about metal carriers. To have an insight about the metal speciation at molecular level, X-Ray Absorption spectroscopy (XAS) was performed at Zn K-edge. The first analyses of Orne sediment cores evidenced different particle size distribution and sediment consolidation levels. Yet the cores showed that below a layer of apparently recent sediments (about 10-20 cm), lie highly contaminated ones. Zn and Pb content in deep sediment layers reach several thousands ppm, where they appeared mainly as Zn and Pb sulphides. Also, the high content of iron in deep sediments resulted in the presence of different iron phases: hematite, wuestite, magnetite, goethite, sulphides (pyrite), as well as undefined iron-silicate. In addition, interstitial waters contained high values of available metals (Zn: 500-35000 ppm, Pb: 150-5700 ppm, Cd: 1-10ppm), which might cause a greater concern than solid-bound metals, especially when river bed sediments are disturbed.

Assessment of trace metal contamination in stream sediments of the Tuul River, Mongolia

NASA Astrophysics Data System (ADS)

Dalai, B.

2011-12-01

Thirty four sediment samples were collected in Ulaanbaatar basin, along the Tuul River which is the main source of water for the capital city Ulaanbaatar, Mongolia. The catchment can be divided three parts (upper, middle, and lower) according to the extent of urbanization. The upper part of the river basin is comparatively less affected by human activity and it can be represent the natural background condition. The middle part is the urban area of Ulaanbaatar and lower part extends SW of the end of the urban area mostly used for agriculture and farming activity. The present study focused on the levels of potentially toxic metals such as As, Pb, Zn, Cu, Ni and Cr in order to assess the extent of environmental pollution and to discuss the origin of these contaminants in sediments of the Tuul River using X-ray fluorescence analyses. Metal concentrations in the sediments are discussed by comparison with average Upper Continental Crust values (UCC) and ecological risk assessment by reference to sediment quality guidelines (SQG). The results showed thet average abundances of metals are measurable contrast between upper, middle and lower parts of the river. The Upper part and its surrounding area's sediment signature indicated that more depletion comparatively other parts (Pb, Zn, Cu, Ni and Cr), whereas enrichment sign did not detect. However, among the Upper part sediments, two samples (NA1 and NA2) enriched with trace metals which sampled from Nalaikh area were significantly affected by coal mining activity. Most metals are (As, Pb, Zn, Cu and Ni) higher in the middle part (within the city) than the upper and lower part due to the urban activities. The small tributaries such as Selbe, Uliastai, Gachuurt and Tolgoit were significantly affected by urban activities and highest values are detected from them. Lower part significantly enriched with Cr (av 98 ppm). Highest concentration of Cr (183 ppm) was at Shuvuu which is receiving point of domestic and industrial wastewater discharge. However all three parts show depletion in some chalcophile and HFSE elements (Cu, Ni, Cr, Sr, Nb, Zr, Th, Sc). This depletion of elements relative to UCC suggest that the river sediments were derived from a highly felsic crustal source. The assessment of ecological risk assessment result showed that adverse aquatic biological effects caused by As and Cr. While, concentration of Pb, Zn, Cu and Ni are generally below their respective Threshold effect level (TEL), in middle part reaches to reach values bordering on the Probable effect level (PEL). This indicated that anthropogenic contribution in the urban areas, increasing values above a naturally low regional background.

Phytoplankton and sediments in Gulf of Mexico

NASA Technical Reports Server (NTRS)

2002-01-01

Affected both by terrestrial factors like agriculture, deforestation, and erosion, and by marine factors like salinity levels, ocean temperature and water pollution, coastal environments are the dynamic interface between land and sea. In this MODIS image from January 15, 2002, the Gulf of Mexico is awash in a mixture of phytoplankton and sediment. Tan-colored sediment is flowing out into the Gulf from the Mississippi River, whose floodplain cuts a pale, wide swath to the right of center in the image, and also from numerous smaller rivers along the Louisiana coast (center). Mixing with the sediment are the multi-colored blue and green swirls that reveal the presence of large populations of marine plants called phytoplankton. Phytoplankton populations bloom and then fade, and these cycles affect fish and mammals-including humans-higher up the food chain. Certain phytoplankton are toxic to both fish and humans, and coastal health departments must monitor ecosystems carefully, often restricting fishing or harvesting of shellfish until the blooms have subsided.

Natural Environmental Hazards Reflected in High-Altitude Patagonian Lake Sediments (lake Caviahue, Argentina)

NASA Astrophysics Data System (ADS)

Müller, Anne; Scharf, Burkhard; von Tümpling, Wolf; Pirrung, Michael

2009-03-01

Two 6-m long sediment cores drilled in the two basins of Lake Caviahue give new evidence of the impact of natural hazards such as ash fallouts linked to nearby volcanic eruptions in the ecologically sensitive environment of the high-altitude region of the Argentinan Patagonian Andes. The two cores show distinct signals of changes in autochthonous productivity and terrigenous input into the lake from ash fallout as well as from river load and shore erosion. Multiproxy records of the sediments indicate whether these changes can be related to volcanic activity. High values of magnetic susceptibility in the cores reflect periods of basaltic ash fallouts during eruptions of the nearby Copahue Volcano. The southern basin is located in the prevalent direction of ash fallouts and has been affected by these volcanic inputs more intensely than the northern basin of the lake. In contrast, sedimentation and authochthonous productivity in the northern basin are strongly affected by fluvial inputs such as suspended river load and acidic stream waters.

Natural Environmental Hazards Reflected in High-Altitude Patagonian Lake Sediments (Lake Caviahue, Argentina)

NASA Astrophysics Data System (ADS)

Mueller, A.; Pirrung, M.; Scharf, B.; von Tuempling, W.

2007-05-01

Two 6-m long sediment cores drilled in the two basins of Lake Caviahue give new evidence of the impact of natural hazards such as ash fallouts linked to nearby volcanic eruptions in the ecologically sensitive environment of the high-altitude region of the Argentinan Patagonian Andes. The two cores show distinct signals of changes in autochthonous productivity and terrigenous input into the lake from ash fallout, river load and shore erosion. Multiproxy records of the sediments indicate whether these changes can be related to volcanic activity. High values of magnetic susceptibility in the cores reflect periods of basaltic ash fallouts during eruptions of the nearby Copahue volcano. The southern basin is located in the prevalent direction of ash fallouts and has been affected by these volcanic inputs more intensely than the northern basin of the lake. In contrast, sedimentation and authochthonous productivity in the northern basin are strongly affected by fluvial inputs such as suspended river load and acidic stream waters.

Quantifying and tracing sediment mobilized during the 20th century in the South River watershed, western Massachusetts

NASA Astrophysics Data System (ADS)

Dow, S.; Snyder, N. P.; Ouimet, W. B.; Martini, A. M.; Yellen, B.; Woodruff, J. D.; Newton, R. M.

2016-12-01

New England has a long history of anthropogenic activity affecting the landscape, including deforestation, land use changes, and the construction of dams. Dams in particular have the ability to impound vast quantities of sediment eroded off the landscape. The South River in western Massachusetts is an example of a watershed where mill dam construction coincided with deforestation during the 17th-19th centuries, leading to the impoundment of legacy sediment. Along the river, these deposits act as a source of sediment being released back into the river. The Conway Electric Dam (CED), a 17 m tall dam built in 1906, is located downstream of the mill dams (most of which are no longer intact), and provides a 20th century depositional record for the watershed. The purpose of this study is to quantify sedimentation behind the CED and link this to erosion of upstream mill pond and glacial sediment sources using aerial photography, sediment cores, grainsize, and geochemical analyses. We used aerial photographs to map areal changes of the reservoir from 1940-1980, and topographic profiles generated from LiDAR to estimate a volume of 244,000 m3 of sediment stored behind the CED. We dated layers in cores collected at the site with Hg and 137Cs analyses. Overall, the reservoir exhibits a decreasing rate of sediment infilling occurring from 1940-1980, except for a potentially anomalous increase from 1940-1952. Discharge data containing large storm events were compared to sediment infilling rates to identify if a frequency of large storms could account for high rates of erosion and sediment transport; however, sedimentation at the site does not appear to be solely dependent on these large storm events. Preliminary Hg analyses of deposits from the watershed upstream of the CED indicate higher concentrations in mill pond sediment than glacial sediment. Ongoing work with geochemical tracers can potentially provide a robust understanding of sources and 20th century sediment mobilization in the South River watershed, allowing us to quantify the influence of two cycles of dam construction on watershed sediment transport rates.

Mining-Related Sediment and Soil Contamination in a Large Superfund Site: Characterization, Habitat Implications, and Remediation.

PubMed

Juracek, K E; Drake, K D

2016-10-01

Historical mining activity (1850-1970) in the now inactive Tri-State Mining District provided an ongoing source of lead and zinc to the environment including the US Environmental Protection Agency Superfund site located in Cherokee County, southeast Kansas, USA. The resultant contamination adversely affected biota and caused human health problems and risks. Remediation in the Superfund site requires an understanding of the magnitude and extent of contamination. To provide some of the required information, a series of sediment and soil investigations were conducted in and near the Superfund site to characterize lead and zinc contamination in the aquatic and floodplain environments along the main-stem Spring River and its major tributaries. In the Superfund site, the most pronounced lead and zinc contamination, with concentrations that far exceed sediment quality guidelines associated with potential adverse biological effects, was measured for streambed sediments and floodplain soils located within or downstream from the most intensive mining-affected areas. Tributary streambeds and floodplains in affected areas are heavily contaminated with some sites having lead and zinc concentrations that are an order of magnitude (or more) greater than the sediment quality guidelines. For the main-stem Spring River, the streambed is contaminated but the floodplain is mostly uncontaminated. Measured lead and zinc concentrations in streambed sediments, lakebed sediments, and floodplain soils documented a persistence of the post-mining contamination on a decadal timescale. These results provide a basis for the prioritization, development, and implementation of plans to remediate contamination in the affected aquatic and floodplain environments within the Superfund site.

Mining-Related Sediment and Soil Contamination in a Large Superfund Site: Characterization, Habitat Implications, and Remediation

NASA Astrophysics Data System (ADS)

Juracek, K. E.; Drake, K. D.

2016-10-01

Historical mining activity (1850-1970) in the now inactive Tri-State Mining District provided an ongoing source of lead and zinc to the environment including the US Environmental Protection Agency Superfund site located in Cherokee County, southeast Kansas, USA. The resultant contamination adversely affected biota and caused human health problems and risks. Remediation in the Superfund site requires an understanding of the magnitude and extent of contamination. To provide some of the required information, a series of sediment and soil investigations were conducted in and near the Superfund site to characterize lead and zinc contamination in the aquatic and floodplain environments along the main-stem Spring River and its major tributaries. In the Superfund site, the most pronounced lead and zinc contamination, with concentrations that far exceed sediment quality guidelines associated with potential adverse biological effects, was measured for streambed sediments and floodplain soils located within or downstream from the most intensive mining-affected areas. Tributary streambeds and floodplains in affected areas are heavily contaminated with some sites having lead and zinc concentrations that are an order of magnitude (or more) greater than the sediment quality guidelines. For the main-stem Spring River, the streambed is contaminated but the floodplain is mostly uncontaminated. Measured lead and zinc concentrations in streambed sediments, lakebed sediments, and floodplain soils documented a persistence of the post-mining contamination on a decadal timescale. These results provide a basis for the prioritization, development, and implementation of plans to remediate contamination in the affected aquatic and floodplain environments within the Superfund site.

Mining-related sediment and soil contamination in a large Superfund site: Characterization, habitat implications, and remediation

USGS Publications Warehouse

Juracek, Kyle E.; Drake, K. D.

2016-01-01

Historical mining activity (1850–1970) in the now inactive Tri-State Mining District provided an ongoing source of lead and zinc to the environment including the US Environmental Protection Agency Superfund site located in Cherokee County, southeast Kansas, USA. The resultant contamination adversely affected biota and caused human health problems and risks. Remediation in the Superfund site requires an understanding of the magnitude and extent of contamination. To provide some of the required information, a series of sediment and soil investigations were conducted in and near the Superfund site to characterize lead and zinc contamination in the aquatic and floodplain environments along the main-stem Spring River and its major tributaries. In the Superfund site, the most pronounced lead and zinc contamination, with concentrations that far exceed sediment quality guidelines associated with potential adverse biological effects, was measured for streambed sediments and floodplain soils located within or downstream from the most intensive mining-affected areas. Tributary streambeds and floodplains in affected areas are heavily contaminated with some sites having lead and zinc concentrations that are an order of magnitude (or more) greater than the sediment quality guidelines. For the main-stem Spring River, the streambed is contaminated but the floodplain is mostly uncontaminated. Measured lead and zinc concentrations in streambed sediments, lakebed sediments, and floodplain soils documented a persistence of the post-mining contamination on a decadal timescale. These results provide a basis for the prioritization, development, and implementation of plans to remediate contamination in the affected aquatic and floodplain environments within the Superfund site.

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

USGS Publications Warehouse

Langland, Michael J.

2015-01-01

The U.S. Geological Survey (USGS) has conducted numerous sediment transport studies in the Susquehanna River and in particular in three reservoirs in the Lower Susquehanna River Basin to determine sediment transport rates over the past century and to document changes in storage capacity. The Susquehanna River is the largest tributary to Chesapeake Bay and transports about one-half of the total freshwater input and substantial amounts of sediment and nutrients to the bay. The transported loads are affected by deposition in reservoirs (Lake Clarke, Lake Aldred, and Conowingo Reservoir) behind three hydropower dams. The geometry and texture of the deposited sediments in each reservoir upstream from the three dams has been a subject of research in recent decades. Particle size deposition and sediment scouring processes are part of the reservoir dynamics. A Total Maximum Daily Load (TMDL) for nitrogen, phosphorus, and sediment was established for Chesapeake Bay to attain water-quality standards. Six states and the District of Columbia agreed to reduce loads to the bay and to meet load allocation goals for the TMDL. The USGS has been estimating annual sediment loads at the Susquehanna River at Marietta, Pennsylvania (above Lake Clarke), and Susquehanna River at Conowingo, Maryland (below Conowingo Reservoir), since the mid-1980s to predict the mass balance of sediment transport through the reservoir system. Using streamflow and sediment data from the Susquehanna River at Harrisburg, Pennsylvania (upstream from the reservoirs), from 1900 to 1981, sediment loads were greatest in the early to mid-1900s when land disturbance activities from coal production and agriculture were at their peak. Sediment loads declined in the 1950s with the introduction of agricultural soil conservation practices. Loads were dominated by climatic factors in the 1960s (drought) and 1970s (very wet) and have been declining since the 1980s through 2012. The USGS developed a regression equation to predict the sediment scour load for daily mean streamflows greater than 300,000 cubic feet per second for the Lower Susquehanna River reservoirs. A compilation of data from various sources produced a range in total sediment transported through the reservoir system and allowed for apportioning to source (watershed or scour) for various streamflows. In 2011, Conowingo Reservoir was estimated to be about 92 percent of sediment storage capacity. Since construction of Conowingo Dam in 1929 through 2012, approximately 470 million tons of sediment was transported down the Susquehanna River into the reservoir system, approximately 290 million tons were trapped, and approximately 180 million tons were transported to Chesapeake Bay. Spatial and estimated total sand deposition in Conowingo Reservoir based on historical sediment cores indicated continued migration of sand downgradient toward the dam and the winnowing of silts and clays near the dam due to scour.

When the same hydraulics conditions lead to different depositional patterns: case of an idealised delta

NASA Astrophysics Data System (ADS)

Peltier, Yann; Erpicum, Sébastien; Archambeau, Pierre; Pirotton, Michel; Dewals, Benjamin

2016-04-01

Deltas are complex hydrosystems and ecosystems resulting from the interactions of a river system with a water body almost at rest. Anthropogenic factors (hydropower, flood management, development in the floodplains) lead to dramatic changes in sediment transport in the rivers and in sediment management practice. From continuous, the sediment transport becomes increasingly intermittent, with long periods of deficit in the sediment supply and short periods characterized by large supplies. Understanding how these intermittencies in the sediment supply affect the delta morphodynamics is of paramount importance for predicting the possible evolution and functioning of deltas. Deltas can reasonably be idealised as a reservoir, with an inlet channel representing the river and the sudden enlargement of the reservoir representing the water body at rest. Using such an ideal configuration enables the assessment of the influence of individual geometric and hydraulic parameters on the depositional patterns responsible for the morphodynamic evolution of the delta. Recent literature has shown that for very similar hydraulic boundary conditions, two very different types of flow fields may develop ("straight jet" vs. "meandering jet"), leading to totally different depositional patterns. In turn, these distinct depositional patterns affect the flow itself through a two-way coupling between the hydrodynamics and the morphodynamics of the deposits. These complex processes will be discussed in the proposed presentation, based on the results of over 160 experimental tests and corresponding numerical simulations.

Sediment impact assessment of check-dam removal strategies on a mountain river in Taiwan

NASA Astrophysics Data System (ADS)

Kuo, W.; Wang, H.; Stark, C. P.

2011-12-01

Dam removal is important for reconnecting river habitats and restoring the free flow of water and sediment, so managing accumulated sediments is crucial in dam removal planning as the cost and potential impacts of dam removal can vary substantially depending on local conditions. A key uncertainty in dam removal is the fate of reservoir sediment stored upstream of the dam. Release of impounded sediment could raise downstream bed elevations leading to flooding, increase lateral channel mobility leading to bank erosion, and potentially bury downstream ecologically sensitive habitats if the sediment is fine. The ability to predict the sediment impacts of dam removal in highly sediment-filled systems is thus increasingly important as the number of such dam-removal cases is growing. Due to the safety concerns and the need for habitat restoration for the Formosan landlocked salmon, the Shei-Pa National Park in Taiwan removed the 15m high Chijiawan "No. 1 Check Dam" in late May 2011. During the planning process prior to removal, we conducted field surveys, numerical simulations, and flume experiments to determine sediment impacts and to suggest appropriate dam removal strategies. We collected river-bed topography and sediment bulk samples in 2010 to establish the channel geometry and grain-size distribution for modeling input. The scaled flume experiment was designed to provide insights on how and if the position of a notch location and size would affect the rate and amount of reservoir erosion under particular discharges. Observations indicated that choices of notch location can force the river to migrate differently. For long-term prediction, we used the quasi-two-dimensional numerical model NETSTARS (Network of Stream Tube model for Alluvial River Simulation) to simulate the channel responses. These simulations indicated that high suspended sediment concentrations would be the most likely major concern in the first year, while concerns for downstream sediment deposition would be minor. We then compared the experimental and numerical predictions with the response of the river to the actual removal. Comparisons of river bed topography pre- and post-dam removal suggest that the predictions provided solid information but also highlight discrepancies between the model predictions and the field data that have implications for future dam-removal assessments.

River bed Elevation Changes and Increasing Flood Hazards in the Nisqually River at Mount Rainier National Park, Washington

NASA Astrophysics Data System (ADS)

Halmon, S.; Kennard, P.; Beason, S.; Beaulieu, E.; Mitchell, L.

2006-12-01

Mount Rainier, located in Southwestern Washington, is the most heavily glaciated volcano of the Cascade Mountain Range. Due to the large quantities of glaciers, Mount Rainier also has a large number of braided rivers, which are formed by a heavy sediment load being released from the glaciers. As sediment builds in the river, its bed increases, or aggrades,its floodplain changes. Some contributions to a river's increased sediment load are debris flows, erosion, and runoff, which tend to carry trees, boulders, and sediment downstream. Over a period of time, the increased sediment load will result in the river's rise in elevation. The purpose of this study is to monitor aggradation rates, which is an increase in height of the river bed, in one of Mount Rainier's major rivers, the Nisqually. The studied location is near employee offices and visitor attractions in Longmire. The results of this study will also provide support to decision makers regarding geological hazard reduction in the area. The Nisqually glacier is located on the southern side of the volcano, which receives a lot of sunlight, thus releasing large amounts of snowmelt and sediment in the summer. Historical data indicate that several current features which may contribute to future flooding, such as the unnatural uphill slope to the river, which is due to a major depositional event in the late 1700s where 15 ft of material was deposited in this area. Other current features are the glaciers surrounding the Nisqually glacier, such as the Van Trump and Kaultz glaciers that produced large outbursts, affecting the Nisqually River and the Longmire area in 2001, 2003, and 2005. In an effort to further explore these areas, the research team used a surveying device, total station, in the Nisqually River to measure elevation change and angles of various positions within ten cross sections along the Longmire area. This data was then put into GIS for analyzation of its current sediment level and for comparison to previous cross sections, which were in 1993 and 2005. Results of the data analysis revealed changes in altitude of the sediment, as well as new areas of built up sediment. For example, a 7 foot increase in elevation, which was not revealed in the 2005 data, indicated there was an increased amount of debris that traveled from upstream. Further data will be obtained once all the cross sections are completed and data is closer analyzed.

Continental sedimentary processes decouple Nd and Hf isotopes

NASA Astrophysics Data System (ADS)

Garçon, Marion; Chauvel, Catherine; France-Lanord, Christian; Huyghe, Pascale; Lavé, Jérôme

2013-11-01

The neodymium and hafnium isotopic compositions of most crustal and mantle rocks correlate to form the "Terrestrial Array". However, it is now well established that whereas coarse detrital sediments follow this trend, fine-grained oceanic sediments have high Hf ratios relative to their Nd isotopic ratios. It remains uncertain whether this "decoupling" of the two isotopic systems only occurs in the oceanic environment or if it is induced by sedimentary processes in continental settings. In this study, the hafnium and neodymium isotopic compositions of sediments in large rivers is expressly used to constrain the behavior of the two isotopic systems during erosion and sediment transport from continent to ocean. We report major and trace element concentrations together with Nd and Hf isotopic compositions of bedloads, suspended loads and river banks from the Ganges River and its tributaries draining the Himalayan Range i.e. the Karnali, the Narayani, the Kosi and the Marsyandi Rivers. The sample set includes sediments sampled within the Himalayan Range in Nepal, at the Himalayan mountain front, and also downstream on the floodplain and at the outflow of the Ganges in Bangladesh. Results show that hydrodynamic sorting of minerals explains the entire Hf isotopic range, i.e. more than 10 εHf units, observed in the river sediments but does not affect the Nd isotopic composition. Bedloads and bank sediments have systematically lower εHf values than suspended loads sampled at the same location. Coarse-grained sediments lie below or on the Terrestrial Array in an εHf vs. εNd diagram. In contrast, fine-grained sediments, including most of the suspended loads, deviate from the Terrestrial Array toward higher εHf relative to their εNd, as is the case for oceanic terrigenous clays. The observed Nd-Hf decoupling is explained by mineralogical sorting processes that enrich bottom sediments in coarse and dense minerals, including unradiogenic zircons, while surface sediments are enriched in fine material with radiogenic Hf signatures. The data also show that Nd-Hf isotopic decoupling increases with sediment transport in the floodplain to reach its maximum at the river mouth. This implies that the Nd-Hf isotopic decoupling observed in worldwide oceanic clays and river sediments is likely to have the same origin. Finally, we estimated the Nd-Hf isotopic composition of the present-day mantle if oceanic sediments had never been subducted and conclude that the addition of oceanic sediments with their anomalous Nd-Hf isotopic compositions has slowly shifted the composition of the Earth's mantle towards more radiogenic Hf values through time.

Numerical modelling of fine-grained sediments remobilization in heavily polluted streams. Case study: Elbe and Bílina River, Czech Republic.

NASA Astrophysics Data System (ADS)

Kaiglová, Jana; Langhammer, Jakub; Jiřinec, Petr; Janský, Bohumír; Chalupová, Dagmar

2014-05-01

The study aimed to estimate remobilization of channel and riparian cohesive sediment of streams, heavily polluted by industrial emmissions. There were analyzed four stream stretches in Czech Republic: (1) Elbe River from Usti nad Labem to the boundary with Germany; (2) Bílina river, draining industrial and mining areas of Northwest Bohemia; (3) Midstream reach of Czech Elbe by the confluence with Vltava river, affected by chemical industry and (4) fluvial lakes in the riparian zone of Czech Elbe river downstream of Pardubice burdened by old loads from heavy chemical industry. Sediments of clay and silt character bedded in the riparian water-courses are regarded heavily polluted by wide range of toxic matters. In the sediment samples, there were found elevated concentrations of persistent organic matters (DDT, PCB, HCH, Fluoranthen), Heavy metals (Hg, As, Cd), and others. The pollution in sediment is resulting from the unregulated heavy industrial production in the area in the second half of 20th century during the socialistic regime in Czech republic that still play an important role in Elbe river water quality. The main goal of the study was to evaluate the risk of remobilization of polluted sediments by the assessment of discharge (values and return periods), initiating remobilization of sediment from the river bed. The modeling stems on basic assumption, that once the sediment is elevated from the bed, it could be transported far downstream in the form of suspended load. The evaluation was made on the basis of numerical hydrodynamic calculation coupled with sediment transport model. The MIKE by DHI modelling software with different levels of schematization was used according the flow conditions and available data sources. For 50 km stretch of Bílina river the 1D schematization (MIKE 11) was selected as the discharges driving remobilization were expected within the extent of channel capacity due to the stream regulation. For the lower and middle course of Elbe river and the riparian sediment evaluation the 2D schematization (MIKE 21 C) was selected. It enabled to distinguish flow characteristics in the zone with complicated hydrodynamic conditions. The risk of remobilization of fine-grained sediments was evaluated in order to define a threshold discharge value after that the spreading of pollution can be expected. The major contribution of the study, realized in the framework of international iniciative ELSA was the identification of threshold values for potential remobilization of sediment burdened by old loads in different environments. These threshold values are important information for identification and mitigation of risks related with old loads and hydrological extremes. From methodological point of view the study verified validity of applied distinct approaches for fine-grained sediment remobilization assessment and identified limits for their application. Key words: sediment, remobilization, old loads, modelling, hydrodynamics, Elbe river

Water and sediment study of the Snake River watershed, Colorado, Oct. 9-12, 2001

USGS Publications Warehouse

Fey, D.L.; Church, S.E.; Unruh, D.M.; Bove, D.J.

2002-01-01

The Snake River watershed, located upstream from Dillon Reservoir in the central mountains of Colorado, has been affected by historical base-metal mining. Trout stocked in the Snake River for recreational purposes do not survive through the winter. Sediment cores analyzed by previous investigators from the reservoir revealed elevated concentrations of base metals and mercury. We collected 36 surface water samples (filtered and unfiltered) and 38 streambed-sediment samples from streams in the Snake River watershed. Analyses of the sediment and water samples show that concentrations of several metals exceed aquatic life standards in one or both media. Ribbon maps showing dissolved concentrations of zinc, cadmium, copper, and manganese in water (0.45-micron filtered and corrected for the ameliorating effect of hardness), and copper, cadmium, and zinc in sediment indicate reaches where toxic effects on trout would be expected and stream reaches where toxicity standards for rainbow, brown, and brook trout are exceeded. Instantaneous loads for sulfate, strontium, iron, cadmium, copper, and zinc were calculated from 0.45-micron-filtered water concentrations and discharge measurements were made at each site. Sulfate and strontium behave conservatively, whereas copper, cadmium, and zinc are reactive. The dissolved copper load entering the reservoir is less than 20 percent of the value calculated from some upper reaches; copper is transferred to suspended and or streambed sediment by sorption to iron oxyhydroxides. Higher percentages of zinc and cadmium reach the reservoir in dissolved form; however, load calculations indicate that some of these metals are also precipitated out of solution. The most effective remediation activities should be concentrated on reducing the dissolved loads of zinc, cadmium, and copper in two reaches of lower Peru Creek between the confluence with the Snake River and Cinnamon Gulch. We analyzed all streambed sediment for mercury and selected streambed-sediment and reservoir core samples for lead isotope signatures. Results indicate that the mercury anomaly in the reservoir sediment was not from any known source in the Snake River, Blue River, or Tenmile Creek watersheds. Its source remains an enigma.

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

NASA Astrophysics Data System (ADS)

Warrick, J. A.

2013-12-01

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

Effect of ship locking on sediment oxygen uptake in impounded rivers

NASA Astrophysics Data System (ADS)

Lorke, A.; McGinnis, D. F.; Maeck, A.; Fischer, H.

2012-12-01

In the majority of large river systems, flow is regulated and/or otherwise affected by operational and management activities, such as ship locking. The effect of lock operation on sediment-water oxygen fluxes was studied within a 12.9 km long impoundment at the Saar River (Germany) using eddy-correlation flux measurements. The continuous observations cover a time period of nearly 5 days and 39 individual locking events. Ship locking is associated with the generation of surges propagating back and forth through the impoundment which causes strong variations of near-bed current velocity and turbulence. These wave-induced flow variations cause variations in sediment-water oxygen fluxes. While the mean flux during time periods without lock operation was 0.5 ± 0.1 g m-2 d-1, it increased by about a factor of 2 to 1.0 ± 0.5 g m-2 d-1within time periods with ship locking. Following the daily schedule of lock operations, fluxes are predominantly enhanced during daytime and follow a pronounced diurnal rhythm. The driving force for the increased flux is the enhancement of diffusive transport across the sediment-water interface by bottom-boundary layer turbulence and perhaps resuspension. Additional means by which the oxygen budget of the impoundment is affected by lock-induced flow variations are discussed.

Selected elements and organic chemicals in bed sediment and fish tissue of the Tualatin River basin, Oregon, 1992-96

USGS Publications Warehouse

Bonn, Bernadine A.

1999-01-01

This report describes the results of a reconnaissance survey of elements and organic compounds found in bed sediment and fish tissue in streams of the Tualatin River Basin. The basin is in northwestern Oregon to the west of the Portland metropolitan area (fig. 1). The Tualatin River flows for about 80 miles, draining an area of about 712 square miles, before it enters the Willamette River. Land use in the basin changes from mostly forested in the headwaters, to mixed forest and agriculture, to predominately urban. The basin supports a growing population of more than 350,000 people, most of whom live in lower parts of the basin. Water quality in the Tualatin River and its tributaries is expected to be affected by the increasing urbanization of the basin.

Observations of Lower Mississippi River Estuarine Dynamics: Effects of the Salt Wedge on Sediment Deposition

NASA Astrophysics Data System (ADS)

Ramirez, M. T.; Allison, M. A.

2017-12-01

The lowermost Mississippi River is subject to salt-wedge estuarine conditions during seasonally low flow, when seaward flow is unable to overcome density stratification. Previous studies in the Mississippi River salt wedge have shown the deposition of a fine sediment layer accumulating several mm/day beneath the reach where the salt wedge is present. Field studies were conducted during low flow in 2012-2015 utilizing ADCP, CTD, LISST, and physical samples to observe the physics of the salt wedge reach and to calculate rates and character of sediment trapping beneath the salt wedge. The field observations were summarized using a two-layer box-model representation of the reach to calculate water and sediment budgets entering, exiting, and stored within the reach. The salt wedge reach was found to be net depositional at rates up to 1.8 mm/day. The mechanism for transferring sediment mass from the downstream-flowing fluvial layer to the upstream-flowing marine layer appears to be flocculation, evidenced in LISST data by a spike in sediment particle diameters at the halocline. Applying reach-averaged rates of sediment trapping to a time-integrated model of salt-wedge position, we calculated annual totals ranging from 0.025 to 2.2 million tons of sediment deposited beneath the salt wedge, depending on salt-wedge persistence and upstream extent. Most years this seasonal deposit is remobilized during spring flood following the low-flow estuarine season, which may affect the timing of sediment delivery to the Gulf of Mexico, as well as particulate organic carbon, whose transport trajectory mirrors that of mineral sediment. These results are also relevant to ongoing dredging efforts necessary to maintain the economically-important navigation pathway through the lower Mississippi River, as well as planned efforts to use Mississippi River sedimentary resources to build land in the degrading Louisiana deltaic coast.

Global Overview On Delivery Of Sediment To The Coast From Tropical River Basins

NASA Astrophysics Data System (ADS)

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

2011-12-01

Depending on definition, the tropics occupy between 16% and 19% of the earth's land surface, and discharge ~18.5% of the earth's fluvial water runoff. These flow regimes are driven by three types of sub-regional climate: rainforest, monsoon, and savannah. Even though the tropics include extreme precipitation events, particularly for the SE Asian islands, the general rainfall pattern alternates between wet and dry seasons as the ITCZ follows the sun and where annual monsoonal rain occurs. ITCZ convective rainfall is the dominant style of precipitation but this can be influenced by rare intra-tropical cyclone events, and by atmospheric river events set up by strong monsoonal conditions. Though a rainy season is normal (for example, portions of India discharge in summer may reach 50 times that of winter), the actual rainfall events are in the form of short bursts of precipitation (hours to days) separated by periods of dry (hours to weeks). Some areas of the tropics receive more than 100 thunderstorms per year. Rivers respond to this punctuated weather by seasonal flooding. For the smaller island nations and locales (e.g. Indonesia, Philippines, Borneo, Hainan, PNG, Madagascar, Hawaii, Taiwan) flash floods are common. Larger tropical river systems (Niger, Ganges, Brahmaputra, Congo, Amazon, Orinoco, Magdalena) show typical seasonally modulated discharges. The sediment flux from tropical rivers is approximately 17% to 19% of the global total - however individual river basins offer a wide range in sediment yields reflecting highly variable differences in their hinterland lithology, tectonic activity and volcanism, land-sliding, and relief. Human influences also greatly influence the range for tropical river sediment yield. Some SE Asian Rivers continue to be greatly affected by deforestation, road construction, and monoculture plantations. Sediment flux is more than twice the pre-Anthropocene flux in many of these SE Asian countries, especially where dams and reservoir emplacements do not impact sediment delivery, as is the case in most temperate regions.

Importance of background values in assessing the impact of heavy metals in river ecosystems: case study of Tisza River, Serbia.

PubMed

Štrbac, Snežana; Kašanin Grubin, Milica; Vasić, Nebojša

2017-11-30

The main objective of this paper is to evaluate how a choice of different background values may affect assessing the anthropogenic heavy metal pollution in sediments from Tisza River (Serbia). The second objective of this paper is to underline significance of using geochemical background values when establishing quality criteria for sediment. Enrichment factor (EF), geoaccumulation index (I geo ), pollution load index (PLI), and potential ecological risk index (PERI) were calculated using different background values. Three geochemical (average metal concentrations in continental crust, average metal concentrations in shale, and average metal concentrations in non-contaminated core sediment samples) and two statistical methods (delineation method and principal component analyses) were used for calculating background values. It can be concluded that obtained information of pollution status can be more dependent on the use of background values than the index/factor chosen. The best option to assess the potential river sediment contamination is to compare obtained concentrations of analyzed elements with concentrations of mineralogically and texturally comparable, uncontaminated core sediment samples. Geochemical background values should be taken into account when establishing quality criteria for soils, sediments, and waters. Due to complexity of the local lithology, it is recommended that environmental monitoring and assessment include selection of an appropriate background values to gain understanding of the geochemistry and potential source of pollution in a given environment.

Heavy metal pollution status and ecological risks of sediments under the influence of water transfers in Taihu Lake, China.

PubMed

Liu, Jiajia; Wang, Peifang; Wang, Chao; Qian, Jin; Hou, Jun

2017-01-01

The effects of water transfer projects on water channels and the receiving water involved need to be understood. In this research, the compositions and particle size distributions of surface sediment and the Cd, Cr, Cu, Ni, Pb, and Zn contents and distributions in the sediment along a water transfer route from the Wangyu River to Taihu Lake, China, were studied. The correlative relationship between the grain size trend and heavy metal content distribution suggested that heavy metals in Wangyu River sediment have affected the heavy metal contents of Taihu Lake sediment through silt and clay migrating in the transferred water. Enrichment factors and potential ecological risk values were calculated. Low levels of potential ecological risks are posed at 20 sampling sites in Taihu Lake, but higher-to-serious risks (potential ecological risk values >275) are posed at all Wangyu River sites. Toxicity of heavy metals (Cd, Cu, Zn, and Ni) in the Wangyu River sediments is more serious than those in the Taihu Lake, but is similar to the entrance of Gonghu Bay. Multivariate statistical analyses (Pearson correlation, cluster, and factor analyses) suggested heavy metals in the study area have many sources, and the relationships between particle migration and heavy metal contents indicated transferring water are likely to lead to adverse ecological risks being posed in Taihu Lake.

Progress report number 2: investigations of some sedimentation characteristics of sand-bed streams

USGS Publications Warehouse

Hubbell, D.W.

1960-01-01

Hydraulic and sediment characteristics at six river sections upstream and downstream from the confluence of the Middle Loup and Dismal Rivers were measured and studied to determine some of the interrelationships between variables and the differences that exist between common variables when two flows unite. The two streams, which flow through the Sandhills region of Nebraska, have about the same water discharge, sediment concentration, and particle-size distribution of suspended sediment and bed material. Sediment discharges and flow resistances varied widely, although water discharges remained almost constant. The factor affecting the variations was water temperature, which ranged from 32° to 80° F. The bed form, which also varied with the water temperature, seemed to have a dominating influence on the sediment discharge, flow resistance, and possibly the vertical distribution of velocity and suspended sediment. Multiple regression with parameters derived from dimensional analysis yielded an expression for predicting the flow resistance and the widths and depths of individual channel sections. Contrary to those near many other confluences, slopes were steeper and channels were wider downstream from the junction of the two rivers than they were upstream. An investigation of specific sediment-transport phenomena and field procedures was made during 1956 and 1957 in cooperation with the U.S. Bureau of Reclamation. The purposes of this investigation were to provide information on the regime of rivers and to improve the procedures related to the collection of sediment data. The basic data and results of the studies made in 1956 were presented in progress report number 1, "Investigations of Some Sedimentation Characteristics of a Sand-Bed Stream." Some of the basic data and results of the studies made in 1957 are given in this report.

Initial sediment transport model of the mining-affected Aries River Basin, Romania

USGS Publications Warehouse

Friedel, Michael J.; Linard, Joshua I.

2008-01-01

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

Longitudinal distribution of Chironomidae (Diptera) downstream from a dam in a neotropical river.

PubMed

Pinha, G D; Aviz, D; Lopes Filho, D R; Petsch, D K; Marchese, M R; Takeda, A M

2013-08-01

The damming of a river causes dangerous consequences on structure of the environment downstream of the dam, modifying the sediment composition, which impose major adjustments in longitudinal distribution of benthic community. The construction of Engenheiro Sérgio Motta Dam in the Upper Paraná River has caused impacts on the aquatic communities, which are not yet fully known. This work aimed to provide more information about the effects of this impoundment on the structure of Chironomidae larvae assemblage. The analysis of data of physical and chemical variables in relation to biological data of 8 longitudinal sections in the Upper Paraná River showed that composition of Chironomidae larvae of stations near Engenheiro Sérgio Motta Dam differed of the other stations (farther of the Dam). The predominance of coarse sediments at stations upstream and finer sediments further downstream affected the choice of habitat by different morphotypes of Chironomidae and it caused a change in the structure of this assemblage in the longitudinal stretch.

Fate of linear alkylbenzene sulfonate in the Mississippi River

USGS Publications Warehouse

Tabor, C.F.; Barber, L.B.

1996-01-01

The 2 800-km reach of the Mississippi River between Minneapolis, MN, and New Orleans, LA, was examined for the occurrence and fate of linear alkylbenzene sulfonate (LAS), a common anionic surfactant found in municipal sewage effluents. River water and bottom sediment were sampled in the summer and fall of 1991 and in the spring of 1992. LAS was analyzed using solid- phase extraction/derivatization/gas chromatography/mass spectrometry. LAS was present on all bottom sediments at concentrations ranging from 0.01 to 20 mg/kg and was identified in 21% of the water samples at concentrations ranging from 0.1 to 28.2 ??g/L. The results indicate that LAS is a ubiquitous contaminant on Mississippi River bottom sediments and that dissolved LAS is present mainly downstream from the sewage outfalls of major cities. The removal of the higher LAS homologs and external isomers indicates that sorption and biodegradation are the principal processes affecting dissolved LAS. Sorbed LAS appears to degrade slowly.

Concentrations, fluxes, and yields of nitrogen, phosphorus, and suspended sediment in the Illinois River basin, 1996-2000

USGS Publications Warehouse

Terrio, Paul J.

2006-01-01

Concentrations, spatial and temporal variations, and fluxes of nitrogen, phosphorus, and suspended sediment were determined for 16 streams in the Illinois River Basin, Illinois from October 1996 through September 2000. Water samples were collected through the National Water-Quality Assessment's Lower Illinois River Basin (LIRB) and Upper Illinois River Basin (UIRB) Study Units on a monthly to weekly frequency from watersheds representing predominantly agricultural and urban land, as well as areas of mixed land-use. Streams in agricultural watersheds had high concentrations and fluxes of nitrate nitrogen, whereas streams in predominantly urban watersheds had high concentrations (above background levels) of ammonia nitrogen, organic nitrogen, and phosphorus. Median concentrations of nitrate nitrogen and total phosphorus were similar at the two Illinois River sampling stations (Illinois River at Ottawa, Ill. and Illinois River at Valley City, Ill.) that represented the downstream points of the UIRB and LIRB Study Units, respectively, and integrated multiple land-use areas. Concentrations of nitrogen were typically highest in the spring and lowest in the fall in agricultural watersheds, but highest in the winter in urban watersheds. Phosphorus concentrations in urban watersheds were highest in the fall and winter, but there was minimal seasonal variation in phosphorus concentrations in agricultural watersheds. Concentrations of nitrate and total nitrogen were affected primarily by non-point sources and hydrologic factors such as streamflow, storm intensity, watershed configuration, and soil permeability, whereas concentrations of phosphorus were affected largely by point-source contributions that typically have little seasonal variation. Seasonal variation in hydrologic conditions was an important factor for seasonal variation in nutrient concentration. Fluxes and yields of nitrogen and phosphorus forms varied substantially throughout the Illinois River Basin, and yields of specific nutrient forms were determined primarily by upstream land uses. Yields of nitrate nitrogen were highest in predominantly agricultural watersheds, whereas yields of phosphorus and ammonia nitrogen were highest in urban watersheds with wastewater effluent contributions. Yields of both total nitrogen and total phosphorus were similar at the two Illinois River stations representing the integrated UIRB and LIRB Study Units. Concentrations of suspended sediment ranged from 1 to 3,110 milligrams per liter (mg/L), with median concentrations generally higher in the UIRB. Suspended-sediment concentrations were highest and most variable in the LaMoine River Basin. The median concentration of suspended sediment in the Illinois River at Valley City, Ill. (155 mg/L) was twice as high as that at Ottawa, Ill. (80 mg/L). Fluxes of suspended sediment generally corresponded to watershed size and yields from agricultural watersheds were larger than yields from urban watersheds. The flux in the Illinois River at Valley City, Ill. (4,880,000 tons per year) was approximately four times the flux in the Illinois River at Ottawa, Ill. (1,060,000 tons per year).

Bioavailability of Mercury to Riverine Food Webs as a Function of Flood-Event Inundation of Channel Boundary Sediments

NASA Astrophysics Data System (ADS)

Singer, M. B.; Pellachini, C.; Blum, J. D.; Marvin-DiPasquale, M. C.; Donovan, P. M.

2013-12-01

Bioavailability of sediment-adsorbed contaminants to food webs in river corridors is typically controlled by biological, chemical, and physical factors, but understanding of their respective influences is limited due to a dearth of landscape-scale investigations of these biogeochemical links. Studies that account for the dynamics and interactions of hydrology and sediment transport in affecting the reactivity of sediment-adsorbed heavy metals such as mercury (Hg) are particularly lacking. Sequences of flood events generate complex inundation histories with banks, terraces, and floodplains that have the potential to alter local redox conditions and thereby affect the oxidation of elemental Hg0 to inorganic Hg(II), and the microbial conversion of Hg(II) to methylmercury (MeHg), potentially increasing the risk of Hg uptake into aquatic food webs. However, the probability distributions of saturation/inundation frequency and duration are typically unknown for channel boundaries along sediment transport pathways, and landscape-scale characterizations of Hg reactivity are rare along contaminated rivers. This research provides the first links between the dynamics of physical processes and biochemical processing and uptake into food webs in fluvial systems beset by large-scale mining contamination. Here we present new research on Hg-contaminated legacy terraces and banks along the Yuba River anthropogenic fan, produced by 19th C. hydraulic gold mining in Northern California. To assess the changes in Hg(II) availability for methylation and MeHg bioavailability into the food web, we combine numerical modeling of streamflow with geochemical assays of total Hg and Hg reactivity to identify hot spots of toxicity within the river corridor as a function of cycles of wetting/drying. We employ a 3D hydraulic model to route historical streamflow hydrographs from major flood events through the Yuba and Feather Rivers into the Central Valley to assess the frequency and duration of saturation/inundation of channel boundary sediments. We compare these spatiotemporal modeling results to sediment total Hg and stannous chloride ';reducible' Hg(II) concentrations (the latter as a proxy for Hg(II) availability for methylation) along this ~70 km swath of river corridor. Finally, we evaluate these potential hot spots of Hg toxicity against MeHg concentrations in local aquatic biota at several trophic levels. The research will provide the basis for new models describing the evolution of toxic substances in river corridors and may prove helpful in explaining the contribution of Hg to food webs of the San Francisco Bay-Delta as an enduring legacy of California's 19th C. Gold Rush.

Spatial variability of surface-sediment porewater pH and related water-column characteristics in deep waters of the northern South China Sea

NASA Astrophysics Data System (ADS)

Shao, Changgao; Sui, Yi; Tang, Danling; Legendre, Louis

2016-12-01

This study analyzes the pH of surface-sediment porewater (i.e. 2-3 cm below the water-sediment interface), and concentrations of CaCO3 and organic carbon (OC) in 1192 sediment cores from the northern South China Sea, in water depths ranging from 137 to 3702 m. This is the first study in the literature to analyze the large-scale spatial variability of deep-water surface-sediment pH over a large ocean basin. The data showed strong spatial variations in pH. The lowest pH values (<7.3) were observed south of Hainan Island, an area that is affected by summer upwelling and freshwater runoff from the Pearl and Red Rivers. Moderately low pH values (generally 7.3-7.5) occurred in two other areas: a submarine canyon, where sediments originated partly from the Pearl River and correspond to a paleo-delta front during the last glacial period; and southwest of Taiwan Island, where waters are affected by the northern branch of the Kuroshio intrusion current (KIC) and runoff from Taiwan rivers. The surface sediments with the highest pH (⩾7.5, and up to 8.3) were located in a fourth area, which corresponded to the western branch of the KIC where sediments have been intensively eroded by bottom currents. The pH of surface-sediment porewater was significantly linearly related to water depth, bottom-water temperature, and CaCO3 concentration (p < 0.05 for the whole sampling area). This study shows that the pH of surface-sediment porewater can be sensitive to characteristics of the overlying water column, and suggests that it will respond to global warming as changes in surface-ocean temperature and pH progressively reach deeper waters.

Assessment of sediments in the riverine impoundments of national wildlife refuges in the Souris River Basin, North Dakota

USGS Publications Warehouse

Tangen, Brian A.; Laubhan, Murray K.; Gleason, Robert A.

2014-01-01

Accelerated sedimentation of reservoirs and riverine impoundments is a major concern throughout the United States. Sediments not only fill impoundments and reduce their effective life span, but they can reduce water quality by increasing turbidity and introducing harmful chemical constituents such as heavy metals, toxic elements, and nutrients. U.S. Fish and Wildlife Service national wildlife refuges in the north-central part of the United States have documented high amounts of sediment accretion in some wetlands that could negatively affect important aquatic habitats for migratory birds and other wetland-dependent wildlife. Therefore, information pertaining to sediment accumulation in refuge impoundments potentially is important to guide conservation planning, including future management actions of individual impoundments. Lands comprising Des Lacs, Upper Souris, and J. Clark Salyer National Wildlife Refuges, collectively known as the Souris River Basin refuges, encompass reaches of the Des Lacs and Souris Rivers of northwestern North Dakota. The riverine impoundments of the Souris River Basin refuges are vulnerable to sedimentation because of the construction of in-stream dams that interrupt and slow river flows and because of post-European settlement land-use changes that have increased the potential for soil erosion and transport to rivers. Information regarding sediments does not exist for these refuges, and U.S. Fish and Wildlife Service personnel have expressed interest in assessing refuge impoundments to support refuge management decisions. Sediment cores and surface sediment samples were collected from impoundments within Des Lacs, Upper Souris, and J. Clark Salyer National Wildlife Refuges during 2004–05. Cores were used to estimate sediment accretion rates using radioisotope (cesium-137 [137Cs], lead-210 [210Pb]) dating techniques. Sediment cores and surface samples were analyzed for a suite of elements and agrichemicals, respectively. Examination of core characteristics along the depth profile suggests that there has been regular sediment mixing and removal, as well as non-uniform sediment deposition with time. Estimated mean accretion rates based on the three methods of determination (two time markers for 137Cs, 210Pb) ranged from 0.22–0.35 centimeters per year, and approximately 70 percent of cores had less 137Cs than expected. Concentrations of sediment-associated elements generally were within reported reference ranges, and all agrichemicals analyzed were below detection limits. Results suggest that there does not appear to be widespread sediment accumulation in impoundments of the Souris River Basin refuges. In addition, there were no identifiable patterns among sedimentation rates from the upstream (Des Lacs, Upper Souris) to the downstream (J. Clark Salyer) refuges. There were, however, apparent upstream to downstream patterns of increased concentrations of some elements (for example, aluminum, boron, and vanadium) that may warrant further exploration. Future related monitoring and research efforts should focus on areas with high potential for sediment accumulation, such as upstream areas adjacent to dams, to identify potential sediment problems before they become too severe. Further, assessments of suspended sediments transported in the Des Lacs and Souris Rivers would augment interpretation of sedimentation data by identifying potential sediment sources and areas with the greatest potential for accumulation.

Changing sediment budget of the Mekong: Cumulative threats and management strategies for a large river basin.

PubMed

Kondolf, G Mathias; Schmitt, Rafael J P; Carling, Paul; Darby, Steve; Arias, Mauricio; Bizzi, Simone; Castelletti, Andrea; Cochrane, Thomas A; Gibson, Stanford; Kummu, Matti; Oeurng, Chantha; Rubin, Zan; Wild, Thomas

2018-06-01

Two decades after the construction of the first major dam, the Mekong basin and its six riparian countries have seen rapid economic growth and development of the river system. Hydropower dams, aggregate mines, flood-control dykes, and groundwater-irrigated agriculture have all provided short-term economic benefits throughout the basin. However, it is becoming evident that anthropic changes are significantly affecting the natural functioning of the river and its floodplains. We now ask if these changes are risking major adverse impacts for the 70 million people living in the Mekong Basin. Many livelihoods in the basin depend on ecosystem services that will be strongly impacted by alterations of the sediment transport processes that drive river and delta morpho-dynamics, which underpin a sustainable future for the Mekong basin and Delta. Drawing upon ongoing and recently published research, we provide an overview of key drivers of change (hydropower development, sand mining, dyking and water infrastructures, climate change, and accelerated subsidence from pumping) for the Mekong's sediment budget, and their likely individual and cumulative impacts on the river system. Our results quantify the degree to which the Mekong delta, which receives the impacts from the entire connected river basin, is increasingly vulnerable in the face of declining sediment loads, rising seas and subsiding land. Without concerted action, it is likely that nearly half of the Delta's land surface will be below sea level by 2100, with the remaining areas impacted by salinization and frequent flooding. The threat to the Delta can be understood only in the context of processes in the entire river basin. The Mekong River case can serve to raise awareness of how the connected functions of river systems in general depend on undisturbed sediment transport, thereby informing planning for other large river basins currently embarking on rapid economic development. Copyright © 2017 Elsevier B.V. All rights reserved.

Environmental impact assessments of the Xiaolangdi Reservoir on the most hyperconcentrated laden river, Yellow River, China.

PubMed

Kong, Dongxian; Miao, Chiyuan; Wu, Jingwen; Borthwick, Alistair G L; Duan, Qingyun; Zhang, Xiaoming

2017-02-01

The Yellow River is the most hyperconcentrated sediment-laden river in the world. Throughout recorded history, the Lower Yellow River (LYR) experienced many catastrophic flood and drought events. To regulate the LYR, a reservoir was constructed at Xiaolangdi that became operational in the early 2000s. An annual water-sediment regulation scheme (WSRS) was then implemented, aimed at flood control, sediment reduction, regulated water supply, and power generation. This study examines the eco-environmental and socioenvironmental impacts of Xiaolangdi Reservoir. In retrospect, it is found that the reservoir construction phase incurred huge financial cost and required large-scale human resettlement. Subsequent reservoir operations affected the local geological environment, downstream riverbed erosion, evolution of the Yellow River delta, water quality, and aquatic biodiversity. Lessons from the impact assessment of the Xiaolangdi Reservoir are summarized as follows: (1) The construction of large reservoirs is not merely an engineering challenge but must also be viewed in terms of resource exploitation, environmental protection, and social development; (2) long-term systems for monitoring large reservoirs should be established, and decision makers involved at national policy and planning levels must be prepared to react quickly to the changing impact of large reservoirs; and (3) the key to solving sedimentation in the LYR is not Xiaolangdi Reservoir but instead soil conservation in the middle reaches of the Yellow River basin. Proper assessment of the impacts of large reservoirs will help promote development strategies that enhance the long-term sustainability of dam projects.

Holocene provenance shift of suspended particulate matter in the Amazon River basin

NASA Astrophysics Data System (ADS)

Höppner, Natalie; Lucassen, Friedrich; Chiessi, Cristiano M.; Sawakuchi, André O.; Kasemann, Simone A.

2018-06-01

The strontium (Sr), neodymium (Nd) and lead (Pb) isotope signatures of suspended particulate matter (SPM) in rivers reflect the radiogenic isotope signatures of the rivers' drainage basin. These signatures are not significantly affected by weathering, transport or depositional cycles, but document the sedimentary contributions of the respective sources. We report new Sr, Nd and Pb isotope ratios and element concentrations of modern SPM from the Brazilian Amazon River basin and document the past evolution of the basin by analyzing radiogenic isotopes of a marine sediment core from the slope off French Guiana archiving the last 40 kyr of Amazon River SPM, and the Holocene section of sediment cores raised between the Amazon River mouth and the slope off French Guiana. The composition of modern SPM confirms two main source areas, the Andes and the cratonic Shield. In the marine sediment core notable changes occurred during the second phase of Heinrich Stadial 1 (i.e. increased proportion of Shield rivers SPM) and during the last deglaciation (i.e. increased proportion of Madeira River SPM) together with elsewhere constant source contributions. Furthermore, we report a prominent offset in Sr and Nd isotopic composition between the average core value (εNd: -11.7 ± 0.9 (2SD), 87Sr/86Sr: 0.7229 ± 0.0016 (2SD)) and the average modern Amazon River SPM signal (εNd: -10.5 ± 0.5 (2SD), 87Sr/86Sr: 0.7213 ± 0.0036 (2SD)). We suggest that a permanent change in the Amazon River basin sediment supply during the late Holocene to a more Andean dominated SPM was responsible for the offset.

The effects of Hurricane Irene and Tropical Storm Lee on the bed sediment geochemistry of U.S. Atlantic coastal rivers

USGS Publications Warehouse

Horowitz, Arthur J.

2013-01-01

Hurricane Irene and Tropical Storm Lee, both of which made landfall in the U.S. between late August and early September 2011, generated record or near record water discharges in 41 coastal rivers between the North Carolina/South Carolina border and the U.S./Canadian border. Despite the discharge of substantial amounts of suspended sediment from many of these rivers, as well as the probable influx of substantial amounts of eroded material from the surrounding basins, the geochemical effects on the <63-µm fractions of the bed sediments appear relatively limited [<20% of the constituents determined (256 out of 1394)]. Based on surface area measurements, this lack of change occurred despite substantial alterations in both the grain size distribution and the composition of the bed sediments. The sediment-associated constituents which display both concentration increases and decreases include: total sulfur (TS), Hg, Ag, total organic carbon (TOC), total nitrogen (TN), Zn, Se, Co, Cu, Pb, As, Cr, and total carbon (TC). As a group, these constituents tend to be associated either with urbanization/elevated population densities and/or wastewater/solid sludge. The limited number of significant sediment-associated chemical changes that were detected probably resulted from two potential processes: (1) the flushing of in-stream land-use affected sediments that were replaced by baseline material more representative of local geology and/or soils (declining concentrations), and/or (2) the inclusion of more heavily affected material as a result of urban nonpoint-source runoff and/or releases from flooded treatment facilities (increasing concentrations). Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

NASA Astrophysics Data System (ADS)

Mestdagh, Sebastiaan; Bagaço, Leila; Braeckman, Ulrike; Ysebaert, Tom; De Smet, Bart; Moens, Tom; Van Colen, Carl

2018-05-01

Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC). An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands). The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater-bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our understanding of the regulation of ecosystem functioning and the impact of habitat alterations such as sediment deposition.

Characterizing Sediment Supply to Rivers: Effects of Lithology, Climate, Weathering and Erosion on Rock-fragment Abundance in Granitic, Hillslope Soils

NASA Astrophysics Data System (ADS)

Riebe, C. S.; Marshall, J. A.; Sklar, L. S.; Granger, D. E.

2008-12-01

River incision sets the pace of landscape evolution and so is crucial to linkages among climate, tectonics and topography. Theoretical and experimental studies indicate that bedrock river incision should be regulated by both the quantity and caliber of sediment supply, which together affect the availability and persistence of bed-scouring tools in the channel. Rates of sediment supply are now quantified routinely using cosmogenic- radionuclide-based (CRN) measurements of hillslope erosion rates. Although grain-size data are also measured routinely (e.g., as part of state and federal soil surveys), they are not widely available for soils with well-constrained rates of erosion and weathering. As a result, there is much to learn about how weathering and erosion interrelate to regulate grain-size distributions in hillslope soils. Moreover, we lack a strong empirical basis for investigating how the rate and caliber of sediment supply affect bedrock river incision in natural systems. Here we compare new grain-size data with existing CRN-based rates of erosion and weathering for a series of granitic soils at two climatically diverse sites in the Sierra Nevada, California. Our results indicate that the percentage of coarse material---which presumably becomes the bedload that abrades and lowers channels---varies significantly across each site. At the colder, wetter site, differences in grain size and soil depth are substantial, despite little variability in erosion rates; coarse material abundance appears to increase with the density of bedrock outcrops, which increases with hillslope gradients, according to previous work. At the hotter, drier site, where rates of erosion and weathering vary by 10-fold, soil thickness and texture and the abundance of outcrops do not vary systematically across the landscape. We speculate that the differences in soil development across our two sites partly reflect effects of small differences in the ratio of biotite to hornblende in the parent rock. We discuss implications for constraining the rate and caliber of sediment supply to rivers.

Climate, wildfire, and erosion ensemble foretells more sediment in western USA watersheds

USGS Publications Warehouse

Sankey, Joel B.; Kreitler, Jason R.; Hawbaker, Todd; McVay, Jason L.; Miller, Mary Ellen; Mueller, Erich R.; Vaillant, Nicole M.; Lowe, Scott E.; Sankey, Temuulen T.

2017-01-01

The area burned annually by wildfires is expected to increase worldwide due to climate change. Burned areas increase soil erosion rates within watersheds, which can increase sedimentation in downstream rivers and reservoirs. However, which watersheds will be impacted by future wildfires is largely unknown. Using an ensemble of climate, fire, and erosion models, we show that post-fire sedimentation is projected to increase for nearly nine-tenths of watersheds by > 10% and for more than one-third of watersheds by > 100% by the 2041 to 2050 decade in the western USA. The projected increases are statistically significant for more than eight-tenths of the watersheds. In the western USA, many human communities rely on water from rivers and reservoirs that originates in watersheds where sedimentation is projected to increase. Increased sedimentation could negatively impact water supply and quality for some communities, in addition to affecting stream channel stability and aquatic ecosystems.

Sediment Transport Variability in Global Rivers: Implications for the Interpretation of Paleoclimate Signals

NASA Astrophysics Data System (ADS)

Syvitski, J. P.; Hutton, E. W.

2001-12-01

A new numerical approach (HydroTrend, v.2) allows the daily flux of sediment to be estimated for any river, whether gauged or not. The model can be driven by actual climate measurements (precipitation, temperature) or with statistical estimates of climate (modeled climate, remotely-sensed climate). In both cases, the character (e.g. soil depth, relief, vegetation index) of the drainage terrain is needed to complete the model domain. The HydroTrend approach allows us to examine the effects of climate on the supply of sediment to continental margins, and the nature of supply variability. A new relationship is defined as: $Qs = f (Psi) Qs-bar (Q/Q-bar)c+-σ where Qs-bar is the long-term sediment load, Q-bar is the long-term discharge, c and sigma are mean and standard deviation of the inter-annual variability of the rating coefficient, and Psi captures the measurement errors associated with Q and Qs, and the annual transients, affecting the supply of sediment including sediment and water source, and river (flood wave) dynamics. F = F(Psi, s). Smaller-discharge rivers have larger values of s, and s asymptotes to a small but consistent value for larger-discharge rivers. The coefficient c is directly proportional to the long-term suspended load (Qs-bar) and basin relief (R), and inversely proportional to mean annual temperature (T). sigma is directly proportional to the mean annual discharge. The long-term sediment load is given by: Qs-bar = a R1.5 A0.5 TT $ where a is a global constant, A is basin area; and TT is a function of mean annual temperature. This new approach provides estimates of sediment flux at the dynamic (daily) level and provides us a means to experiment on the sensitivity of marine sedimentary deposits in recording a paleoclimate signal. In addition the method provides us with spatial estimates for the flux of sediment to the coastal zone at the global scale.

Heavy metals pollution status in surface sediments (rivers and artifical lakes, Serbia)

NASA Astrophysics Data System (ADS)

Sakan, Sanja; Đorđević, Dragana

2017-04-01

Potentially hazardous trace elements, often in literature referred as "heavy metals", are deemed serious pollutants due to their toxicity, persistence and non-degradability in the environment. These elements play an important role in extent of water pollution and threaten the health of populations and ecosystems. As the sink of heavy metals, sediment beds adsorb metals in quantities that are many times higher than those found in the water column in the long-term polluted water environment. It is believed that most of the metal content, as much as 90% in aquatic sediments is bound to sediments. Metal contamination in these sediments could be directly affect the river water quality, resulting in potential consequences to the sensitive lowest levels of the food chain and ultimately to human health. The objective of this research was the evaluation of heavy metal contamination level in sediments of the most important rivers and artificial lakes in Serbia. The heavy metal enrichment in studied sediments was conducted by using: determination of total metal content, sequential extraction procedure for the fractionation of studied elements, quantification of the metal enrichment degree in the sediments by calculating geo-accumulation indices, determination of actual and potential element availability and application of BRAI index for the assessment of heavy metal bioavailability. The sediments were found to be contaminated by heavy metals to various extents, mostly with Cd, Cu, and Zn. The significant variation in heavy metal distribution among samples collected in this large region, encompassing all Serbian watersheds, suggests the selective contamination of sediments by heavy metals. Elevated concentrations of elements in most cases were detected in samples of river sediments, since artificial lake reservoirs are usually built in rural areas, where the less anthropogenic pollution. Rivers often flow through the towns and these water basins less or more loaded micronutrients, toxic substances, organic or inorganic, waste materials, depending on the species and type of industrial processes that are often without the necessary technological and mandatory treatment directly discharged into them. Due to the potential risk of heavy metal pollution in studied sediments, pollution prevention and control measurements seems necessary, especially in areas where we found increased levels of these elements.

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

USGS Publications Warehouse

Macek-Rowland, Kathleen M.

2000-01-01

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

Enhanced sediment delivery in a changing climate in semi-arid mountain basins: Implications for water resource management and aquatic habitat in the northern Rocky Mountains

Treesearch

Jaime R. Goode; Charles H. Luce; John M. Buffington

2012-01-01

The delivery and transport of sediment through mountain rivers affects aquatic habitat and water resource infrastructure. While climate change is widely expected to produce significant changes in hydrology and stream temperature, the effects of climate change on sediment yield have received less attention. In the northern Rocky Mountains, we expect climate change to...

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

PubMed

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

2015-01-01

Sulfate, a major component of acid mine drainage (AMD), its migration in an AMD-affected river which located at the Dabaoshan mine area of South China was investigated to pursue the remediation strategy. The existing factors of relatively low pH values of 2.8-3.9, high concentrations of SO4(2-) (∼1940 mg L(-1)) and Fe(3+) (∼112 mg L(-1)) facilitated the precipitation of schwertmannite (Fe8O8(OH)6SO4·nH2O) in the upstream river. Geochemical model calculations implied the river waters were supersaturated, creating the potential for precipitation of iron oxyhydroxides. These minerals evolved from schwertmannite to goethite with the increasing pH from 2.8 to 5.8 along the river. The concentration of heavy metals in river waters was great reduced as a result of precipitation effects. The large size of the exchangeable sulfate pool suggested that the sediments had a strong capacity to bind SO4(2-). The XRD results indicated that schwertmannite was the predominant form of sulfate-bearing mineral phases, which was likely to act as a major sulfate sink by incorporating water-borne sulfate into its internal structure and adsorbing it onto its surface. The small size of reduced sulfur pools and strong oxidative status in the surface sediments further showed that SO4(2-) shifting from water to sediment in form of sulfate reduction was not activated. In short, precipitation of sulfate-rich iron oxyhydroxides and subsequent SO4(2-) adsorption on these minerals as well as water dilution contributed to the attenuation of SO4(2-) along the river waters. Copyright © 2014 Elsevier Ltd. All rights reserved.

Change of microbial community structure and functional gene abundance in nonylphenol-degrading sediment.

PubMed

Wang, Zhao; Yang, Yuyin; He, Tao; Xie, Shuguang

2015-04-01

Biodegradation by autochthonous microbial community is an important way to clean up nonylphenol (NP) from contaminated river sediment. Knowledge of sediment microbial community can aid in our understanding of biological processes related to NP degradation. However, the change in sediment microbial community associated with NP biodegradation remains unclear. The present study investigated the shift in bacterial community structure and NP-degrading gene abundance in response to NP attenuation in river sediment. Sediment microcosms with different levels of 4-NP (0, 100, or 300 μg/g) were constructed. A nearly complete attenuation of NP occurred in the microcosm with 100 μg/g NP after 9 days' incubation, while a residual NP rate of 8.1 % was observed in the microcosm with 300 μg/g NP after 22 days' incubation. Illumina MiSeq sequencing analysis indicated that Gammaproteobacteria, Alphaproteobacteria, and Bacteroidetes predominated in NP-degrading river sediment. Sediment bacterial community structure varied significantly during NP biodegradation and subsequent incubation, which was affected by the level of added NP. The n-alkane biodegradation (alkB) gene abundance showed a significant variation in each NP-amended microcosm (100 or 300 μg/g), while a significant increase in the single component monooxygenase (sMO) gene abundance only occurred in the microcosm spiked with 300 μg/g NP. This study can provide some new insights toward NP-degrading microbial ecology in the environment.

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

USGS Publications Warehouse

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

2013-01-01

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

Water and sediment dynamics in the context of climate change and variability (Cañete river, Peru).

NASA Astrophysics Data System (ADS)

Rosas, Miluska; Vanacker, Veerle; Huggel, Christian; Gutierrez, Ronald R.

2017-04-01

Water erosion is one of the main environmental problems in Peru. The elevated rates of soil erosion are related to the rough topography of the Andes, shallow soils, highly erosive climate and the inappropriate land use management. Agricultural activities are directly affected by the elevated soil erosion rates, either through reduced crop production and/or damage to irrigation infrastructure. Similarly, the development of water infrastructure and hydropower facilities can be negatively affected by high sedimentation rates. However, critical information about sediment production, transport and deposition is still mostly lacking. This paper focuses on sediment dynamics in the context of land use and climate change in the Peruvian Andes. Within the Peruvian Coastal Range, the catchment of the Cañete River is studied as it plays an important role in the social and economic development of the region, and due to its provision of water and energy to rural and urban areas. The lower part of the basin is an arid desert, the middle sub-humid part sustains subsistence agriculture, and the upper part of the basin is a treeless high-elevation puna landscape. Snow cover and glaciers are present at its headwaters located above 5000 m asl. The retreat of glaciers due to climate change is expected to have an impact on water availability, and the production and mobilization of sediment within the river channels. Likewise, climate variability and land cover changes might trigger an important increase of erosion and sediment transport rates. The methodology applied to face this issue is principally based on the analysis of sediment samples recollected in the basin in the period 1998 to 2001, and the application of a water and sediment routing model. The paper presents new data on the sensitivity of water infrastructure and hydropower facilities to climate-induced changes in sediment mobilization.

Runoff of genotoxic compounds in river basin sediment under the influence of contaminated soils.

PubMed

da Costa, Thatiana Cappi; de Brito, Kelly Cristina Tagliari; Rocha, Jocelita Aparecida Vaz; Leal, Karen Alam; Rodrigues, Maria Lucia Kolowski; Minella, Jean Paolo Gomes; Matsumoto, Silvia Tamie; Vargas, Vera Maria Ferrão

2012-01-01

Contaminated sites must be analyzed as a source of hazardous compounds in the ecosystem. Contaminant mobility in the environment may affect sources of surface and groundwater, elevating potential risks. This study looked at the genotoxic potential of samples from a contaminated site on the banks of the Taquari River, RS, Brazil, where potential environmental problems had been identified (pentachlorophenol, creosote and hydrosalt CCA). Samplers were installed at the site to investigate the drainage material (water and particulate soil matter) collected after significant rainfall events. Organic extracts of this drained material, sediment river samples of the Taquari River (interstitial water and sediment organic extracts) were evaluated by the Salmonella/microsome assay to detect mutagenicity and by Allium cepa bioassays (interstitial water and whole sediment samples) to detect chromosomal alterations. Positive mutagenicity results in the Salmonella/microsome assay of the material exported from the area indicate that contaminant mixtures may have drained into the Taquari River. This was confirmed by the similarity of mutagenic responses (frameshift indirect mutagens) of organic extracts from soil and river sediment exported from the main area under the influence of the contaminated site. The Allium cepa test showed significant results of cytotoxicity, mutagenic index and chromosome aberration in the area under the same influence. However, it also showed the same similarity in positive results at an upstream site, which probably meant different contaminants. Chemical compounds such as PAHs, PCF and chromium, copper and arsenic were present in the runoff of pollutants characteristically found in the area. The strategy employed using the Salmonella/microsome assay to evaluate effects of complex contaminant mixtures, together with information about the main groups of compounds present, allowed the detection of pollutant dispersion routes from the contaminated site to the Taquari River sediment. Copyright © 2011 Elsevier Inc. All rights reserved.

Sediment transport and water-quality characteristics and loads, White River, northwestern Colorado, water years 1975-88

USGS Publications Warehouse

Tobin, R.L.

1993-01-01

Streamflow, sediment, and water-quality data are summarized for 6 sites on the White River, Colorado for water years 1975-88. Correlation techniques were used to estimate annual data for unmeasured years. Annual stream discharge in the main stem of the White River ranged from about 200,000 to about 1 million acre-feet. Generally, bedload was less than/= 3.3 percent of total sediment load. Annual suspended-sediment loads ranged from about 2,100 tons at the upstream sites on the North Fork and South Fork of the White River to about 2 million tons at the most downstream site. Average annual suspended-sediment loads ranged from about 11,000 tons at the upstream sites to about 705,000 tons at the most downstream site. Annual capacity losses in a 50,000 acre-ft reservoir could range from less than 0.01 percent near upstream sites to about 2.5 percent near downstream sites. Maximum water temperatures in the White River ranged from less than 20 to 25 C in summer. Specific conductance ranged from 200 to 1,000 microsiemens/cm. Generally, values of pH ranged from 7.6 to 8.8, and concentrations of dissolved oxygen were greater than 6.0 mg/L. In small streamflows, values of pH and dissolved oxygen were affected by biologic processes. Composition of dissolved solids in the White River was mostly calcium, bicarbonate, and(or) sulfate. Changes in the composition of dissolved solids caused by the changes in the concentrations of sodium and sulfate were greatest in small stream discharges. Annual loads of dissolved solids ranged from 21,100 tons in the South Fork to about 480,000 tons at the most downstream site. Total solids transport in the White River was mostly as dissolved solids at upstream sites and mostly as suspended sediment at downstream sites. Concentration ranges of nutrients and trace constituents were determined.

Sediment sampling and processing methods in Hungary, and possible improvements

NASA Astrophysics Data System (ADS)

Tamas, Eniko Anna; Koch, Daniel; Varga, Gyorgy

2016-04-01

The importance of the monitoring of sediment processes is unquestionable: sediment balance of regulated rivers suffered substantial alterations in the past century, affecting navigation, energy production, fish habitats and floodplain ecosystems alike; infiltration times to our drinking water wells have shortened, exposing them to an eventual pollution event and making them vulnerable; and sediment-attached contaminants accumulate in floodplains and reservoirs, threatening our healthy environment. The changes in flood characteristics and rating curves of our rivers are regularly being researched and described, involving state-of-the-art measurement methods, modeling tools and traditional statistics. Sediment processes however, are much less known. Unlike the investigation of flow processes, sediment-related research is scarce, which is partly due to the outdated methodology and poor database background in the specific field. Sediment-related data, information and analyses form an important and integral part of Civil engineering in relation to rivers all over the world. In relation to the second largest river of Europe, the Danube, it is widely known in expert community and for long discussed at different expert forums that the sediment balance of the river Danube has changed drastically over the past century. Sediment monitoring on the river Danube started as early as the end of the 19th century, with scattered measurements carried out. Regular sediment sampling was developed in the first half of the 20th century all along the river, with different station density and monitoring frequencies in different countries. After the first few decades of regular sampling, the concept of (mainly industrial) development changed along the river and data needs changed as well, furthermore the complicated and inexact methods of sampling bed load on the alluvial reach of the river were not developed further. Frequency of suspended sediment sampling is very low along the river, best organized in the upstream countries, where also on tributaries like the Drau/Drava monitoring stations are in operation. Sampling frequency of suspended load is 3 to 7 per year in Hungary, and even lower downstream. Sediment management is a major challenge, as most methods developed until now are unsustainable, require continuous intervention and are expensive as well. However, there is a new focus on the subject in the 21st century, which still lacks uniform methodological recommendations for measurements and analyses, and the number of engineers with sediment expertise and experience is alarmingly low. Data related to sediment quantity are unreliable and often contradictory. It is difficult to produce high quality long-term databases that could support and enable the mathematical calibration of sediment transport models. Sediment measurements are different in different countries in Europe. Even in Hungary, sampling and laboratory techniques have changed several times in the past. Also, sediment sampling was never really systhematic, and the sampling campaigns did not follow the hydrological processes. That is how sediment data can hardly be compared; and the data series are inhomogeneous and they cannot be statistically analysed. The majority of the existing sediment data in Hungary are not suitable for the data supply needs of state-of-the-art numerical modeling. It is even problematic to describe the connections between water flow (discharge) and sediment transport, because data are scarce and irregular. Even the most modern measurement methods (Acoustic Doppler Current Profiler [ADCP], or Laser In Situ Scattering and Transmissometry [LISST]) need calibration, which means field sampling and laboratory processing. For these reasons we need (both quantitatively and qualitively) appropriate sampling of sediment. In frame of projects and programs of the Institute for Hydraulic engineering and Water management of Eötvös József College, we developed the methodology of field-data collection campaigns in relation to sediment data in order to meet the calibration and verification needs of state-of-the art numerical modeling, and to be able to collect comparable data series for statistical analyses.

Concentrations of selected metals in Quaternary-age fluvial deposits along the lower Cheyenne and middle Belle Fourche Rivers, western South Dakota, 2009-10

USGS Publications Warehouse

Stamm, John F.; Hoogestraat, Galen K.

2012-01-01

The headwaters of the Cheyenne and Belle Fourche Rivers drain the Black Hills of South Dakota and Wyoming, an area that has been affected by mining and ore-milling operations since the discovery of gold in 1875. A tributary to the Belle Fourche River is Whitewood Creek, which drains the area of the Homestake Mine, a gold mine that operated from 1876 to 2001. Tailings discharged into Whitewood Creek contained arsenopyrite, an arsenic-rich variety of pyrite associated with gold ore, and mercury used as an amalgam during the gold-extraction process. Approximately 18 percent of the tailings that were discharged remain in fluvial deposits on the flood plain along Whitewood Creek, and approximately 25 percent remain in fluvial deposits on the flood plain along the Belle Fourche River, downstream from Whitewood Creek. In 1983, a 29-kilometer (18-mile) reach of Whitewood Creek and the adjacent flood plain was included in the U.S. Environmental Protection Agency's National Priority List of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, commonly referred to as a "Superfund site." Listing of this reach of Whitewood Creek was primarily in response to arsenic toxicity of fluvial deposits on the flood plain. Lands along the lower Cheyenne River were transferred to adjoining States and Tribes in response to the Water Resources Development Act (WRDA) of 1999. An amendment in 2000 to WRDA required a study of sediment contamination of the Cheyenne River. In response to the WRDA amendment, the U.S. Geological Survey completed field sampling of reference sites (not affected by mine-tailing disposal) along the lower Belle Fourche and lower Cheyenne Rivers. Reference sites were located on stream terraces that were elevated well above historical stream stages to ensure no contamination from historical mining activity. Sampling of potentially contaminated sites was performed on transects of the active flood plain and adjacent terraces that could potentially be inundated during high-flow events. Sampling began in 2009 and was completed in 2010. A total of 74 geochemical samples were collected from fluvial deposits at reference sites, and 473 samples were collected from potentially contaminated sites. Sediment samples collected were analyzed for 23 metals, including arsenic and mercury. Sequential replicate, split duplicate, and field quality-control samples were analyzed for quality assurance of data-collection methods. The metal concentrations in sediment samples and location information are presented in this report in electronic format (Microsoft Excel), along with non-parametric summary statistics of those data. Cross-sectional topography is graphed with arsenic and mercury concentrations on transects at the potentially contaminated sites. The mean arsenic concentration in reference sediment samples was 8 milligrams per kilogram (mg/kg), compared to 250, 650, and 76 mg/kg for potentially contaminated sediment samples at the surface of the middle Belle Fourche River site, the subsurface of the middle Belle Fourche River site, and the surface of the lower Cheyenne River site, respectively. The mean mercury concentration in reference sediment samples was 16 micrograms per kilogram (μg/kg), compared to 130, 370, and 71 μg/kg for potentially contaminated sediment samples at the surface of the middle Belle Fourche River site, the subsurface of the middle Belle Fourche River site, and the surface of the lower Cheyenne River site, respectively.

Environmental evolution records reflected by radionuclides in the sediment of coastal wetlands: A case study in the Yellow River Estuary wetland.

PubMed

Wang, Qidong; Song, Jinming; Li, Xuegang; Yuan, Huamao; Li, Ning; Cao, Lei

2016-10-01

Vertical profiles of environmental radionuclides ( 210 Pb, 137 Cs, 238 U, 232 Th, 226 Ra and 4 0 K) in a sediment core (Y1) of the Yellow River Estuary wetland were investigated to assess whether environmental evolutions in the coastal wetland could be recorded by the distributions of radionuclides. Based on 210 Pb and 137 Cs dating, the average sedimentation rate of core Y1 was estimated to be 1.0 cm y -1 . Vertical distributions of natural radionuclides ( 238 U, 232 Th, 226 Ra and 40 K) changed dramatically, reflecting great changes in sediment input. Concentrations of 238 U, 232 Th, 226 Ra and 40 K all had significant positive relationships with organic matter and clay content, but their distributions were determined by different factors. Factor analysis showed that 238 U was determined by the river sediment input while 226 Ra was mainly affected by the seawater erosion. Environmental changes such as river channel migrations and sediment discharge variations could always cause changes in the concentrations of radionuclides. High concentrations of 238 U and 226 Ra were consistent with high accretion rate. Frequent seawater intrusion decreased the concentration of 226 Ra significantly. The value of 238 U/ 226 Ra tended to be higher when the sedimentation rate was low and tide intrusion was frequent. In summary, environmental evolutions in the estuary coastal wetland could be recorded by the vertical profiles of natural radionuclides. Copyright © 2016 Elsevier Ltd. All rights reserved.

Water-quality assessment of the Kentucky River basin, Kentucky; nutrients, sediments, and pesticides in streams, 1987-90

USGS Publications Warehouse

Haag, K.H.; Porter, S.D.

1995-01-01

The U.S. Geological Survey investigated the water quality of the Kentucky River Basin in Kentucky as part of the National Water Quality Assessment program. Data collected during 1987-90 were used to describe the spatial and temporal variability of nutrients, suspended sediment, and pesticides in streams. Concentrations of phosphorus were signifi- cantly correlated with urban and agricultural land use. The high phosphorus content of Bluegrass Region soils was an important source of phosphorus in streams. At many sites in urban areas, all of the stream nitrogen load was attributable to wastewater- treatment-plant effluent. Tributary streams affected by agricultural sources of nutrients contained higher densities of phytoplankton than streams that drained forested areas. Data indicate that a consid- erable percentage of total nitrogen was transported as algal biomass during periods of low discharge. Average suspended-sediment concentrations for the study period were positively correlated with dis- charge. There was a downward trend in suspended- sediment concentrations downstream in the Kentucky River main stem during the study. Although a large amount of suspended sediment originates in the Eastern Coal Field Region, contributions of suspended sediment from the Red River and other tributary streams of the Knobs Region also are important. The most frequently detected herbicides in water samples were atrazine, 2,4-D, alachlor, metolachlor, and dicamba. Diazinon, malathion, and parathion were the most frequently detected organo- phosphate insecticides in water samples. Detectable concentrations of aldrin, chlordane, DDT, DDE, dieldrin, endrin, endosulfan, heptachlor, heptachlor epoxide, and lindane were found in streambed- sediment samples.

Combined Flow Abstraction and Climate Change Impacts on an Aggrading Alpine River

NASA Astrophysics Data System (ADS)

Bakker, M.; Costa, A.; Silva, T. A.; Stutenbecker, L.; Girardclos, S.; Loizeau, J.-L.; Molnar, P.; Schlunegger, F.; Lane, S. N.

2018-01-01

Recent climatic warming and associated glacial retreat may have a large impact on sediment release and transfer in Alpine river basins. Concurrently, the sediment transport capacity of many European Alpine streams is affected by hydropower exploitation, notably where flow is abstracted but the sediment supply downstream is maintained. Here, we investigate the combined effects of climate change and flow abstraction on morphodynamics and sediment transfer in the Borgne River, Switzerland. From photogrammetrically derived historical Digital Elevation Models (DEMs), we find considerable net aggradation of the braided river bed (up to 5 m) since the onset of flow abstraction in 1963. Reaches responded through bed level steepening which was strongest in the upper most reach. Widespread aggradation however did not commence until the onset of glacier retreat in the late 1980s and the dry and warm years of the early 1990s. Upstream flow intake data shows that this aggradation coincided with an increase in sediment supply, although aggradation accounts for no more than 25% of supplied material. The remainder was transferred through the studied reaches. Estimations of bed load transport capacity indicate that flow abstraction reduces transport capacity by 1-2 orders of magnitude. While residual transport rates vary with morphological evolution, they are in the same order of magnitude as the sediment supply rates, which is why significant transport remains. However, the reduction in transport capacity makes the system more sensitive to short-term (annual) changes in climate-driven hydrological variability and climate-induced changes in intake management and sediment delivery rates.

Two dimensional modelling of flood flows and suspended sediment transport: the case of Brenta River

NASA Astrophysics Data System (ADS)

D'Alpaos, L.; Martini, P.; Carniello, L.

2003-04-01

The paper deals with numerical modelling of flood waves and suspended sediment in plain river basins. The two dimensional depth integrated momentum and continuity equations, modified to take into account of the bottom irregularities that strongly affect the hydrodynamic and the continuity in partially dry areas (for example, during the first stages of a plain flooding and in tidal flows), are solved with a standard Galerkin finite element method using a semi-implicit numerical scheme and considering the role both of the small channel network and the regulation dispositive on the flooding wave propagation. Transport of suspended sediment and bed evolution are coupled with the flood propagation through the convection-dispersion equation and the Exner's equation. Results of a real case study are presented in which the effects of extreme flood of Brenta River (Italy) are examinated. The flooded areas (urban and rural areas) are identified and a mitigation solution based on a diversion channel flowing into Venice Lagoon is proposed. We show that this solution strongly reduces the flood risk in the downstream areas and can provide an important sediment source to the Venice Lagoon. Finally, preliminary results of the sediment dispersion in the Venice Lagoon are presented.

Distribution of heavy metals in vegetation surrounding the Blackstone River, USA: considerations regarding sediment contamination and long term metals transport in freshwater riverine ecosystems.

PubMed

Ozdilek, Hasan Goksel; Mathisen, Paul P; Pellegrino, Don

2007-04-01

The Blackstone River, a 74 km interstate stream located in South Central Massachusetts and Rhode Island (USA), has had a long history of problems due to high concentrations of metals such as copper and lead. The river has been subjected to metals load that include contributions from urban runoff, wastewater discharges, contaminated sediments, and also resuspension of contaminated sediments in the river-bed. All of these effects lead to elevated concentrations of metals such as lead, copper, zinc, chromium, cadmium and arsenic. Furthermore, the contaminated sediments located behind impoundments become especially important when higher flows cause resuspension of the previously deposited sediments and associated metals. While it is known that high metals concentrations in this river are found in the bottom sediments, the fate of the metals and impact on the ecosystem are not well known. This paper addresses the potential impacts that metals may have on vegetation and plant tissues in the vicinity of the river Plant tissues (primarily mosses), were collected from a number of sampling sites along a 14 km stretch of this river. At each site, samples were collected from multiple distances from the riverbank. Laboratory analyses made use of both wet digestion and dry ashing digestion methods, followed by analysis using an atomic absorption spectrophotometer. The wet and dry ashing digestion methods yielded similar results, although the results afforded by the dry ashing methods were slightly lower than the results obtained from the wet method. The results showed that the metals concentrations in vegetation (as determined from plant tissue analyses) were generally inversely related to the distance between the vegetation and the riverbank, with higher metals concentrations existing in plant tissues located close to the riverbank. In addition, it was found that the transport of metals concentrations to the terrestrial vegetation adjacent to this section of the Blackstone River was affected by the river morphology and flow characteristics (including velocity, flow rate and depth of flow, which can govern the potential for plant submergence, as well as the dynamics of flow and transport in the soil near the river). The analyses help to provide an improved understanding of metals transport and potential significance of metals contamination in a terrestrial ecosystem that is located adjacent to a river.

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

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

USGS Publications Warehouse

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

2001-01-01

Acid drainage from abandoned mines and from naturally-acidic rocks and soil in the upper Animas River watershed of Colorado generates elevated concentrations of acidity and dissolved metals in stream waters and deposition of metal-contaminated particulates in streambed sediments, resulting in both toxicity and habitat degradation for stream biota. High concentrations of iron (Fe), aluminum (Al), zinc (Zn), copper (Cu), cadmium (Cd), and lead (Pb) occur in acid streams draining headwaters of the upper Animas River watershed, and high concentrations of some metals, especially Zn, persist in circumneutral reaches of the Animas River and Mineral Creek, downstream of mixing zones of acid tributaries. Seasonal variation of metal concentrations is reflected in variation in toxicity of stream water. Loadings of dissolved metals to the upper Animas River and tributaries are greatest during summer, during periods of high stream discharge from snowmelt and monsoonal rains, but adverse effects on stream biota may be greater during winter low-flow periods, when stream flows are dominated by inputs of groundwater and contain greatest concentrations of dissolved metals. Fine stream-bed sediments of the upper Animas River watershed also contain elevated concentrations of potentially toxic metals. Greatest sediment metal concentrations occur in the Animas River upstream from Silverton, where there are extensive deposits of mine and mill tailings, and in mixing zones in the Animas River and lower Mineral Creek, where precipitates of Fe and Al oxides also contain high concentrations of other metals. This report summarizes the findings of a series of toxicity studies in streams of the upper Animas River watershed, conducted on-site and in the laboratory between 1998 and 2000. The objectives of these studies were: (1) to determine the relative toxicity of stream water and fine stream-bed sediments to fish and invertebrates; (2) to determine the seasonal range of toxicity in stream water; (3) to develop site-specific thresholds for toxicity of Zn and Cu in stream water; and (4) to develop models of the contributions of Cu and Zn to toxicity of stream water, which may be used to characterize toxicity before and after planned remediation efforts. We evaluated the toxicity of metal-contaminated sediments by conducting sediment toxicity tests with two species of benthic invertebrates, the midge, Chironomus tentans. and the amphipod, Hyalella azteca. Laboratory toxicity tests with both taxa, exposed to fine stream-bed sediments collected in September 1997, showed some evidence of sediment toxicity, as survival of midge larvae in sediments from Cement Creek (C48) and lower Mineral Creek (M34), and growth of amphipods in sediments from these sites and three Animas River sites (A68, Animas at Silverton; A72, Animas below Silverton, and A73, Animas at Elk Park) were significantly reduced compared to a reference site, South Mineral Creek (SMC) . Amphipods were also exposed to site water and fine stream-bed sediment, separately and in combination, during the late summer low flow period (August-September) of 1998. In these studies, stream water, with no sediment present, from all five sites tested (same sites as above, except C48) caused 90% to 100% mortality of amphipods. In contrast, significant reductions in survival of amphipods occurred at two sites (A72 and SMC) in exposures with field-collected sediment plus stream water, and at only one site (A72) in exposures with sediments and clean overlying water. Concentrations of Zn, Pb, Cu, and Cd were high in both sediment and pore water (interstitial water) from most sites tested, but greatest sediment toxicity was apparently associated with greater concentrations of Fe and/or Al in sediments. These results suggest that fine stream-bed sediments of the more contaminated stream reaches of the upper Animas River watershed are toxic to benthic invertebrates, but that these impacts are less serious than tox

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

PubMed Central

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

2009-01-01

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

Morphodynamics: Rivers beyond steady state

NASA Astrophysics Data System (ADS)

Church, M.; Ferguson, R. I.

2015-04-01

The morphology of an alluvial river channel affects the movement of water and sediment along it, but in the longer run is shaped by those processes. This interplay has mostly been investigated empirically within the paradigm of Newtonian mechanics. In rivers, this has created an emphasis on equilibrium configurations with simple morphology and uniform steady flow. But transient adjustment, whether between equilibrium states or indefinitely, is to be expected in a world in which hydrology, sediment supply, and base level are not fixed. More fundamentally, water flows and all the phenomena that accompany them are inherently unsteady, and flows in natural channels are characteristically nonuniform. The morphodynamics of alluvial river channels is the striking consequence. In this paper, we develop the essential connection between the episodic nature of bed material transport and the production of river morphology, emphasizing the fundamental problems of sediment transport, the role of bar evolution in determining channel form, the role of riparian vegetation, and the wide range of time scales for change. As the key integrative exercise, we emphasize the importance of physics-based modeling of morphodynamics. We note consequences that can be of benefit to society if properly understood. These include the possibility to better be able to model how varying flows drive morphodynamic change, to understand the influence of the sediments themselves on morphodynamics, and to recognize the inherent necessity for rivers that transport bed material to deform laterally. We acknowledge pioneering contributions in WRR and elsewhere that have introduced some of these themes.

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

NASA Astrophysics Data System (ADS)

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

2012-12-01

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

Large Woody Debris Characteristics of Maine Rivers: Its Frequency, Geometry, and Role In Sediment Storage

NASA Astrophysics Data System (ADS)

Magilligan, F. J.; Fisher, B.; Nislow, K.; Wright, J.; Mackey, G.

2006-12-01

Unlike watersheds in other parts of the US, little is known about the function of wood in New England Rivers, especially in Downeast Maine which possesses the few remaining wild runs of Atlantic Salmon in the US. Rivers in this region have been heavily affected by historical and contemporary land use disturbance especially hillslope and riparian logging which combine to limit the supply of large woody debris (LWD). Results from a multi-basin inventory representing over 40 river km of 6 drainages across Downeast Maine indicate LWD mean loadings of appx. 90 pieces per km with less than 1% having diameters> 50 cm with the rest split between 60 % small (10-20 cm) and 39% medium (20-50 cm) sizes. Because of their small size, most of this LWD is oriented parallel (~37%) or downstream (~33%), and channel-spanning stable wood pieces/jams are rare. Salmonid populations appear to depend on overwintering habitat and unlike other regions where LWD serves an important role in pool formation, LWD in Downeast Maine functions primarily as sites of critical sediment storage thus reducing overall channel embeddedness. To capture this function, we cored an array of LWD- related sediment wedges and used the fallout radionuclides, 7Be and 210Pb, to estimate sediment residence times. Results indicate that LWD is an important sediment sink having residence times ranging from the individual event to > several years.

River Suspended Sediment and Particulate Organic Carbon Transport in Two Montane Catchments in the Luquillo Critical Zone Observatory of Puerto Rico over 25 years: 1989 to 2014

NASA Astrophysics Data System (ADS)

Clark, K. E.; Plante, A. F.; Willenbring, J. K.; Jerolmack, D. J.; Gonzalez, G.; Stallard, R. F.; Murphy, S. F.; Vann, D. R.; Leon, M.; McDowell, W. H.

2015-12-01

Physical erosion in mountain catchments mobilizes large amounts of sediment, while exporting carbon and nutrients from forest ecosystems. This study expands from previous studies quantifying river suspended sediment and particulate organic carbon loads in the Luquillo Critical Zone Observatory, in Puerto Rico. We evaluate the influences on river suspended load due to i) underlying basin geology, ii) hillslope debris and biomass supply, and iii) hurricanes and large storms. In the Mameyes and Icacos catchments of the Luquillo Mountains, we estimate suspended sediment and particulate organic carbon yields over a 25-year period using streamflow discharge determined from stage measurements at 15-intervals, with estimates of discharge replacing gaps in data, and over 3000 suspended sediment samples. We estimate variation in suspended sediment loads over time, and examine variation in particulate organic carbon loads. Mass spectrometry was used to determine organic carbon concentrations. We confirm that higher suspended sediment fluxes occurred i) in the highly weathered quartz diorite catchment rather than the predominantly volcaniclastic catchment, ii) on the rising limb of the hydrograph once a threshold discharge had been reached, and iii) during hurricanes and other storm events, and we explore these influences on particulate organic carbon transport. Transport of suspended sediment and particulate organic carbon in the rivers shows considerable hysteresis, and we evaluate the extent to which hysteresis affects particulate fluxes over time and between catchments. Because particulate organic carbon is derived from the critical zone and transported during high flow, our research highlights the role of major tropical storms in controlling carbon storage in the critical zone and the coastal ocean.

Sediment cores as archives of historical changes in floodplain lake hydrology.

PubMed

Lintern, Anna; Leahy, Paul J; Zawadzki, Atun; Gadd, Patricia; Heijnis, Henk; Jacobsen, Geraldine; Connor, Simon; Deletic, Ana; McCarthy, David T

2016-02-15

Anthropogenic activities are contributing to the changing hydrology of rivers, often resulting in their degradation. Understanding the drivers and nature of these changes is critical for the design and implementation of effective mitigation strategies for these systems. However, this can be hindered by gaps in historical measured flow data. This study therefore aims to use sediment cores to identify historical hydrological changes within a river catchment. Sediment cores from two floodplain lakes (billabongs) in the urbanised Yarra River catchment (Melbourne, South-East Australia) were collected and high resolution images, trends in magnetic susceptibility and trends in elemental composition through the sedimentary records were obtained. These were used to infer historical changes in river hydrology to determine both average trends in hydrology (i.e., coarse temporal resolution) as well as discrete flood layers in the sediment cores (i.e., fine temporal resolution). Through the 20th century, both billabongs became increasingly disconnected from the river, as demonstrated by the decreasing trends in magnetic susceptibility, particle size and inorganic matter in the cores. Additionally the number of discrete flood layers decreased up the cores. These reconstructed trends correlate with measured flow records of the river through the 20th century, which validates the methodology that has been used in this study. Not only does this study provide evidence on how natural catchments can be affected by land-use intensification and urbanisation, but it also introduces a general analytical framework that could be applied to other river systems to assist in the design of hydrological management strategies. Copyright © 2015 Elsevier B.V. All rights reserved.

Channel-planform evolution in four rivers of Olympic National Park, Washington, U.S.A.: The roles of physical drivers and trophic cascades

USGS Publications Warehouse

East, Amy E.; Jenkins, Kurt J.; Happe, Patricia J.; Bountry, Jennifer A.; Beechie, Timothy J.; Mastin, Mark C.; Sankey, Joel B.; Randle, Timothy J.

2017-01-01

Identifying the relative contributions of physical and ecological processes to channel evolution remains a substantial challenge in fluvial geomorphology. We use a 74-year aerial photographic record of the Hoh, Queets, Quinault, and Elwha Rivers, Olympic National Park, Washington, U.S.A., to investigate whether physical or trophic-cascade-driven ecological factors—excessive elk impacts after wolves were extirpated a century ago—are the dominant controls on channel planform of these gravel-bed rivers. We find that channel width and braiding show strong relationships with recent flood history. All four rivers have widened significantly in recent decades, consistent with increased flood activity since the 1970s. Channel planform also reflects sediment-supply changes, evident from landslide response on the Elwha River. We surmise that the Hoh River, which shows a multi-decadal trend toward greater braiding, is adjusting to increased sediment supply associated with rapid glacial retreat. In this sediment-routing system with high connectivity, such climate-driven signals appear to propagate downstream without being buffered substantially by sediment storage. Legacy effects of anthropogenic modification likely also affect the Quinault River planform. We infer no correspondence between channel geomorphic evolution and elk abundance, suggesting that trophic-cascade effects in this setting are subsidiary to physical controls on channel morphology. Our findings differ from previous interpretations of Olympic National Park fluvial dynamics and contrast with the classic example of Yellowstone National Park, where legacy effects of elk overuse are apparent in channel morphology; we attribute these differences to hydrologic regime and large-wood availability.

Holocene intramontane lake development: A new model in the Jáchal River Valley, Andean Precordillera, San Juan, Argentina

NASA Astrophysics Data System (ADS)

Colombo, Ferran; Busquets, Pere; Sole de Porta, Nuria; Limarino, Carlos Oscar; Heredia, Nemesio; Rodriguez-Fernandez, Luis Roberto; Alvarez-Marron, Joaquina

2009-10-01

The Jáchal River Valley displays a number of significant Holocene sedimentary accumulations made up of fine-grained materials. These deposits are interpreted as the sedimentary infill of shallow temporary lakes that were generated by slow growing episodes of alluvial fans that obstructed the Jáchal River Valley. The association of fossil remains through the Holocene sedimentary sequence suggests that the accumulation of lacustrine sediments was affected by climate variations. The predominant aridity was punctuated by very few humid episodes characterised by fresh-water gastropoda and the intercalations of muddy sediments. The high proportion of charcoal particles in some samples indicates periodic forest fires. Abundant non-pollen forest remains suggest that an open zone dominated by several types of grasses underwent a dry season during part of the year. The palynomorph associations found in the Jáchal River Valley Holocene lacustrine sediments suggest that the humid conditions were less intense than those in the San Juan River Valley located more than one hundred kilometres southwards. Our study suggests that lake formation could have been controlled by climate oscillation probably related to the ENSO variation at 30° south latitude.

Effects of river regulation on aeolian landscapes, Colorado River, southwestern USA

USGS Publications Warehouse

Draut, Amy E.

2012-01-01

Connectivity between fluvial and aeolian sedimentary systems plays an important role in the physical and biological environment of dryland regions. This study examines the coupling between fluvial sand deposits and aeolian dune fields in bedrock canyons of the arid to semiarid Colorado River corridor, southwestern USA. By quantifying significant differences between aeolian landscapes with and without modern fluvial sediment sources, this work demonstrates for the first time that the flow- and sediment-limiting effects of dam operations affect sedimentary processes and ecosystems in aeolian landscapes above the fluvial high water line. Dune fields decoupled from fluvial sand supply have more ground cover (biologic crust and vegetation) and less aeolian sand transport than do dune fields that remain coupled to modern fluvial sand supply. The proportion of active aeolian sand area also is substantially lower in a heavily regulated river reach (Marble–Grand Canyon, Arizona) than in a much less regulated reach with otherwise similar environmental conditions (Cataract Canyon, Utah). The interconnections shown here among river flow and sediment, aeolian sand transport, and biologic communities in aeolian dunes demonstrate a newly recognized means by which anthropogenic influence alters dryland environments. Because fluvial–aeolian coupling is common globally, it is likely that similar sediment-transport connectivity and interaction with upland ecosystems are important in other dryland regions to a greater degree than has been recognized previously.

Major and trace element distribution in soil and sediments from the Egyptian central Nile Valley

NASA Astrophysics Data System (ADS)

Badawy, W. M.; Ghanim, E. H.; Duliu, O. G.; El Samman, H.; Frontasyeva, M. V.

2017-07-01

The distributions of 32 major and trace elements in 72 surface soil and sediment samples collected from the Asyut to Cairo Nile river section were determined by epithermal neutron activation analysis and compared with corresponding data for the Upper Continental Crust, North American Shale Composite, Average Soil and Average Sediment as well as suspended sediments from Congo and Upper Niger Rivers, in order to establish to which extent the Nile sedimentary material can be related to similar material all over the world as well as to local geology. Their relative distributions indicate the presence of detrital material of igneous origin, most probably resulting from weathering of the Ethiopian Highlands and transported by the Blue Nile, the Nile main tributary. The distributions of nickel, zinc, and arsenic contents suggest that the lower part of the Nile and its surroundings including the Nile Delta is not seriously polluted with heavy metals, so that, in spite of a human activity, which lasted four millennia, the Nile River continues to be less affected by any anthropogenic contamination.

Quantifying hyporheic exchange in a karst stream using 222Rn

NASA Astrophysics Data System (ADS)

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

2013-12-01

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

Medium- and Long-Term Effects of Estrogenic Contaminants on the Middle River Po Fish Community as Reconstructed from a Sediment Core.

PubMed

Viganò, Luigi; Loizeau, J-L; Mandich, A; Mascolo, G

2016-11-01

Recent studies showed that endocrine active compounds (EDs) capable to induce fish gonadal histopathologies, plasma vitellogenin and thyroid disruption, are transported by the River Lambro to the River Po, potentially affecting the fish community of the main Italian river. To assess whether fish relative abundance, composition and health were impaired by the River Lambro, a 3-year survey was undertaken in the main river. Results showed that the tributary supports in the River Po a denser fish community (+43 %), with a higher total biomass (+35 %). The survey also showed niche- and sensitivity-dependent effects, so that three benthopelagic species (bleak, topmouth gudgeon, and bitterling) were, for example, more abundant downstream from the tributary (up to 3.4×), but their sizes were significantly smaller. The present fish community was then compared with that described 30 years before in the same area of the Po River. This comparison highlighted that some fish species have disappeared and many have severely declined. To better evaluate this contrast, a sediment core of the Lambro tributary was analysed for the time trends of natural estrogens (E1, E2, E3), bisphenol A and alkylphenols. The results showed that during the last 50 years the River Lambro has been exposed to high estrogenic activities (16.1 ± 9.3 ng E2 equivalents/g), which inevitably affected also the River Po. In addition, at the time of the previous survey, six species of the main river had skewed sex ratios toward all-female populations, providing evidence that EDs and particularly (xeno)estrogens were already affecting the long-term viability of fish populations. Estrogens thus can be ascribed among the causal factors of fish qualitative and quantitative decline of the River Po, although long-term effects have been likely mitigated by nonconfinement of fish populations and nutrient enrichment.

Application of sedimentary-structure interpretation to geoarchaeological investigations in the Colorado River Corridor, Grand Canyon, Arizona, USA

USGS Publications Warehouse

Draut, A.E.; Rubin, D.M.; Dierker, J.L.; Fairley, H.C.; Griffiths, R.E.; Hazel, J.E.; Hunter, R.E.; Kohl, K.; Leap, L.M.; Nials, F.L.; Topping, D.J.; Yeatts, M.

2008-01-01

We present a detailed geoarchaeological study of landscape processes that affected prehistoric formation and modern preservation of archaeological sites in three areas of the Colorado River corridor in Grand Canyon, Arizona, USA. The methods used in this case study can be applied to any locality containing unaltered, non-pedogenic sediments and, thus, are particularly relevant to geoarchaeology in arid regions. Resolving the interaction of fluvial, aeolian, and local runoff processes in an arid-land river corridor is important because the archaeological record in arid lands tends to be concentrated along river corridors. This study uses sedimentary structures and particle-size distributions to interpret landscape processes; these methods are commonplace in sedimentology but prove also to be valuable, though less utilized, in geoarchaeology and geomorphology. In this bedrock canyon, the proportion of fluvial sediment generally decreases with distance away from the river as aeolian, slope-wash, colluvial, and debris-flow sediments become more dominant. We describe a new facies consisting of 'flood couplets' that include a lower, fine-grained fluvial component and an upper, coarser, unit that reflects subaerial reworking at the land surface between flood events. Grain-size distributions of strata that lack original sedimentary structures are useful within this river corridor to distinguish aeolian deposits from finer-grained fluvial deposits that pre-date the influence of the upstream Glen Canyon Dam on the Colorado River. Identification of past geomorphic settings is critical for understanding the history and preservation of archaeologically significant areas, and for determining the sensitivity of archaeological sites to dam operations. Most archaeological sites in the areas studied were formed on fluvial deposits, with aeolian deposition acting as an important preservation agent during the past millennium. Therefore, the absence of sediment-rich floods in this regulated river, which formerly deposited large fluvial sandbars from which aeolian sediment was derived, has substantially altered processes by which the prehistoric, inhabited landscape formed, and has also reduced the preservation potential of many significant cultural sites.

Characterizing relationships among fecal indicator bacteria, microbial source tracking markers, and associated waterborne pathogen occurrence in stream water and sediments in a mixed land use watershed

EPA Science Inventory

Bed sediments of streams and rivers may store high concentrations of fecal indicator bacteria (FIB) and pathogens. Due to resuspension events, these contaminants can be mobilized into the water column and affect overall water quality. Other bacterial indicators such as microbial ...

Dispersal of river sediment in the Southern California Bight

USGS Publications Warehouse

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

2009-01-01

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

Integral assessment of pollution in the Suquía River (Córdoba, Argentina) as a contribution to lotic ecosystem restoration programs.

PubMed

Merlo, C; Abril, A; Amé, M V; Argüello, G A; Carreras, H A; Chiappero, M S; Hued, A C; Wannaz, E; Galanti, L N; Monferrán, M V; González, C M; Solís, V M

2011-11-01

The Suquía River lower-middle basin (Córdoba, Argentina) is subject to a strong anthropic impact because it receives pollutants from different sources (industries, wastewaters, heavy traffic, agricultural land use, etc.) We have assessed the degree of watershed degradation of Suquía River lower-middle sections through the analysis of different ecosystem compartments (air, water, riparian soil, sediments and biota), in order to provide useful data to be considered in future river restoration programs. Four study sites were selected along the river (La Calera city, Córdoba city, Corazón de María village and Río Primero city) which were sampled during the low- and high-water flow periods. We analyzed: a) chemical and physical characteristics of water, sediments, and riparian soil; b) heavy metal content of water and sediments, and c) semi-volatile organic compounds in air. Besides, pollutant bioindicators such as fish assemblages, lichens (Usnea amblyoclada), vascular plants (Tradescantia pallida), and microorganisms (fecal coliform and Escherichia coli) were used to further assess the status of the river. All analyzed ecological compartments were affected by water pollution, particularly, fish assemblages, sediments and riparian soils by heavy metal and coliform bacteria. Moreover, we detected a possible contribution of sulfur and a high pollutant content in air that merit further research about other air-water exchanges. Accordingly, we strongly suggest that an action to restore or remediate the anthropic effect on the Suquía River be extended to all possible compartments along the river. Copyright © 2011 Elsevier B.V. All rights reserved.

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

USGS Publications Warehouse

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

2015-01-01

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

Combined Climate and Flow Abstraction Impacts on an Aggrading Alpine River

NASA Astrophysics Data System (ADS)

Bakker, M.; Costa, A.; Silva, T. A.; Stutenbecker, L.; Girardclos, S.; Loizeau, J. L.; Molnar, P.; Schlunegger, F.; Lane, S. N.

2017-12-01

Recent climatic warming and associated glacial retreat may have a large impact on sediment release and transfer in Alpine river basins. In parallel, the sediment transport capacity of many European Alpine streams is affected by hydropower exploitation, notably where flow is abstracted but the sediment supply to the headwaters is maintained at flow intakes. Here, we investigate the combined effects of climate change and flow abstraction on morphodynamics and sediment transfer in one such Alpine stream, the Borgne River, Switzerland. A unique dataset forms the basis for determining sediment deposition and transfer: (1) a set of high resolution Digital Elevation Models (DEMs) of braided river reaches is derived through applying Structure from Motion (SfM) photogrammetry to archival aerial photographs available for the period 1959-2014; (2) flow intake management data is used for the reconstruction of (up- and downstream) discharge and sediment supply since 1977. Subsequently we use bedload transport capacity calculations and climate data to assess their relative impact on the system evolution over the last 25 years. From the historical DEMs we find considerable aggradation of the river bed (up to 5 meters) since the onset of flow abstraction in 1963. Rapid and widespread aggradation however did not commence until the onset of glacier retreat in the late 1980s and the dry and notably warm years of the early 1990s. This aggradation coincided with an increase in sediment supply, although it accounts for only c. 25% of supplied material, the remainder was transferred through the studied reaches. Flow abstraction reduces transport capacity by an order of magnitude but the residual transport rates are close to sediment supply rates, which is why significant transport remains. However, the reduction in transport capacity due to direct human impacts in basin hydrology (flow abstraction) makes the system much more sensitive to changes in climate-driven hydrological variability and climate induced changes in intake management and sediment supply rates. This was exemplified by an increasingly strong climate (winter precipitation and summer temperature) influence on the delivery of glacially derived sediment.

Pore-Water Chemistry and Hydrology in a Spring-Fed River: Implications for Hyporheic Control of Nutrient Cycling and Speleogenesis

NASA Astrophysics Data System (ADS)

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

2010-12-01

Hyporheic exchange is important for nutrient cycling in rivers, but little is known about the magnitude of this process in karst systems or its influence on speleogenesis and the formation of river channels. We use four pore-water depth profiles to assess nutrient and carbonate processing in the hyporheic zone (HZ) of the Ichetucknee River (north-central, Florida). Co-located pairs of stilling wells equipped with conductivity, temperature, depth (CTD) sensors are used to continuously monitor the hydraulic gradients within the HZ to determine flow directions and temporal variability of groundwater exchange. The Ichetucknee River is sourced from six major and numerous small springs which discharge from the karstic Floridan Aquifer. Downstream and diel variations in nitrate concentrations, specific conductivity and calcite saturation state reflect in-stream processing, but hyporheic exchange should also influence the overall dynamics of nutrient and carbonate fluxes in the river. Our depth profiles and stilling wells are located at four sites in a cross-channel transect and extend through unconsolidated sediment to the solid carbonate of the Floridan Aquifer 35-156 cm below the river bed. Decreasing DOC, pH, and DO concentrations and increased DIC are indicative of organic carbon remineralization in the shallow sediments. Increasing alkalinity, Ca concentrations, specific conductivity and decreasing calcite saturation state indicate carbonate dissolution being driven by the decreasing pH. Decreasing nitrate concentrations indicate denitrification and increasing phosphate concentration could be a result of carbonate dissolution or OC remineralization. Most of these changes appear to occur in the upper 60cm of sediment, below which many concentrations return to values observed in the groundwater, suggesting water discharges from the Floridan Aquifer at the base of the sediment. Hydraulic head is higher in the pore waters than the river indicating groundwater then discharges to the river. Initial modeling of the system indicates that flow through the channel sediment moves horizontally and discharges into the river through the incised channel rather than upwards through the most reactive hyporheic sediments. While differences in chemical composition between the pore water and river water suggest the chemically altered pore water could affect chemical composition of the river it remains unclear the relative fractions of ground water and chemically altered pore water that flow into the river. Future work will attempt to quantify the magnitude of these exchanges over a range of hydrologic conditions.

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

USGS Publications Warehouse

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

2008-01-01

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

Sedimentation History of Halfway Creek Marsh, Upper Mississippi River National Wildlife and Fish Refuge, Wisconsin, 1846-2006

USGS Publications Warehouse

Fitzpatrick, Faith A.; Knox, James C.; Schubauer-Berigan, Joseph P.

2007-01-01

The history of overbank sedimentation in the vicinity of Halfway Creek Marsh near La Crosse, Wis., was examined during 2005?06 by the U.S. Geological Survey and University of Wisconsin?Madison as part of a broader study of sediment and nutrient loadings to the Upper Mississippi River bottomlands by the U.S. Environmental Protection Agency, U.S. Fish and Wildlife Service, and U.S. Geological Survey. Historical sedimentation patterns and rates were interpreted from field-scale topographic surveys and sediment cores collected from the marsh and upstream flood plains. Historical maps and aerial photographs were used to establish the timing of disturbances and to document changes in channel patterns after Euro-American settlement (post 1846). Episodic overbank sedimentation patterns and rates were linked to watershed agricultural activity, large floods, artificial levee construction, channel alterations, and dam failures over the past 160 years. These forces affected sedimentation on and between levees, the development of alluvial fans and flood-plain splays, and the general pattern of flood-plain sedimentation through the upper and lower marsh. Historical overbank deposits, episodically deposited after about 1860, are as much as 6 feet thick in the upper marsh and as much as 4 feet thick in the lower marsh, representing a total volume of approximately 1.8 million cubic yards. These stratified deposits consist of multiple layers of silt and clay, very fine to fine sand, and some medium to very coarse sand. Coarse-grained deposits are associated with flood-plain splays caused by breaches in artificial levees during large floods. Estimated sedimentation rates were highest from 1919 to 1936 [26,890 cubic yards per year (yd3/yr)] and exceeded by about 30 times the 1846?85 rate of 920 yd3/yr and exceeded by 7 times the 1994?2006 rate of 3,740 yd3/yr. The 1994?2006 sedimentation rate was the lowest since Euro-American settlement, but natural levees along the 1994?2006 channel of Halfway Creek through the lower marsh continued to form and are currently (2006) about 1 foot higher than the surrounding marsh. Natural levee building in the lower marsh from 1994?2006 was accentuated by the lack of overbank sediment storage in the upper marsh. The historical storage of sediment in the upper and lower marsh affects modern streamflow and sediment transport processes of Halfway Creek and Sand Lake Coulee through the marsh, and it also affects marsh vegetation and wildlife habitat. Results from this investigation will help improve the understanding of how past overbank sedimentation patterns continue to influence modern and future water quality, sediment transport, nutrient loads, and water-related resources in riparian habitats common to the Upper Mississippi River National Wildlife and Fish Refuge.

Characteristics and Distribution of Phosphorus in Surface Sediments of Limnetic Ecosystem in Eastern China

PubMed Central

Zhang, Wenqiang; Jin, Xin; Zhu, Xiaolei; Shan, Baoqing

2016-01-01

Phosphorus (P) is an essential nutrient for aquatic organisms; however, excessive P inflow to limnetic ecosystems can induce eutrophication. P concentrations in the rivers, wetlands and lakes of Eastern China have been amplified by fertilizer and sewage inputs associated with the development of industry and agriculture. Yet, knowledge of the distribution and speciation of P is lacking at the regional scale. We determined the distribution and speciation of P in limnetic ecosystems in Eastern China using Standards, Measurements and Testing (SMT) and phosphorus nuclear magnetic resonance (31P-NMR). The results indicate that P pollution in surface sediments was serious. Inorganic P (Pi) was the primary drive of variation in total P (TP) among different river systems, and Pi accounted for 71% to 90% of TP in surface sediment in Eastern China. Also, the concentrations of TP and Pi varied among watersheds and Pi primarily drove the variation in TP in different watersheds. Sediments less than 10-cm deep served as the main P reservoir. Environmental factors affect the speciation and origin of P. NaOH-Pi, HCl-Pi and organic P (Po) were related to pH accordingly at the regional scale. The physicochemical properties of sediments from different limnetic ecosystems affect the P speciation. HCl-Pi was higher in wetland sediments than in riverine and lake sediments in Eastern China. Conversely, NaOH-Pi was lowest in wetland sediments. Total Po concentration was lower in riverine sediments than in other sediments, but Mono-P was higher, with an average concentration of 48 mg kg−1. Diesters-P was highest in lake sediments. By revealing the regional distribution of TP, Pi and Po, this study will support eutrophication management in Eastern China. PMID:27281191

Characterizing Three-Dimensional Mixing Process in a River Confluence using Hydro-acoustical Backscatter and Flow Measurement

NASA Astrophysics Data System (ADS)

Son, Geunsoo; Kim, Dongsu; Kim, YoungDo; Lyu, Siwan; Kim, Seojun

2017-04-01

River confluences are zones where two rivers with different geomorphic and hydraulic characteristics amalgamate, resulting in rapid change in terms of flow regime, sediment entrainment and hydraulic geometry. In these confluence zones, the flow structure is basically complicated responded with concurrent mixing of physical and chemical aquatic properties, and continuous channel morphology could be changed due to erosion and sedimentation. In addition, the confluences are regions in which two rivers join and play an important role in river ecology. In order to characterize the mixing process of confluence for understanding the impacts of a river on the other river, therefore, it has been crucial to analyze the spatial mixing patterns for main streams depending on various inflow conditions of tributaries. However, most conventional studies have mostly relied upon hydraulic or water quality numerical models for understanding mixing pattern analysis of confluences, due to the difficulties to acquire a wide spatial range of in-situ data especially for characterizing this kind of mixing process. Even with intensive in-situ measurements, those researches tended to focus mainly on the hydraulic characteristics such as the flow and morphological complexity of confluence, so that very few studies comprehensively included sediment variation with flow at the same time. In this study, subsequently, flow and sediment mixing characteristics were concurrently investigated in the confluence between Nakdong and Nam river in South Korea, where it has been frequently questioned to determine how Nam river affects Nakdong river that recently have suffered various environmental problems such as green algae bloom and erosion/deposition in the confluence. We basically examined the mixing characteristics of confluence by using acoustic Doppler current profilers (ADCPs) which were used to measure hydraulic factors such as flow rate and depth, as well as measuring the suspended sediment concentration by using acoustic backscatter. Cross-sectional ADCP measurements in a confluence were collected with high spatial resolution in order to analyze the details of spatial distribution in the perspective of the three-dimensional mixing patterns of flow and sediment, where backscatters (or SNR) measured from ADCPs were used to track sediment mixing assuming that it could be a surrogate to estimate the suspended sediment concentration. Raw backscatter data were corrected by considering the beam spreading and absorption by water. Also, an optical Laser diffraction instrument (LISST) was used to verify the method of acoustic backscatter and to collect the particle size distribution of main stream and tributary. In addition, image-based spatial distributions of sediment mixture in the confluence were monitored in various flow conditions by using an unmanned aerial vehicle (UAV), which were compared with the spatial distribution of acoustic backscatter. As results, we found that when acoustic backscatter and flow measurements by ADCPs were well processed, they could be proper indicators to identify the spatial patterns of the three-dimensional mixing process between two rivers.

Sediment source detection by stable isotope analysis, carbon and nitrogen content and CSSI in a small river of the Swiss Plateau

NASA Astrophysics Data System (ADS)

SchindlerWildhaber, Yael; Alewell, Christine; Birkholz, Axel

2014-05-01

Suspended sediment (SS) and organic matter in rivers can harm the fauna by affecting health and fitness of free swimming fish and by causing siltation of the riverbed. The temporal and spatial dynamics of sediment, carbon (C) and nitrogen (N) during the brown trout spawning season in a small river of the Swiss Plateau were assessed and C isotopes as well as the C/N atomic ratio were used to distinguish autochthonous and allochthonous sources of organic matter in SS loads. The visual basic program IsoSource with 13Ctot and 15N as input isotopes was used to quantify the temporal and spatial sources of SS. We determined compound specific stable carbon isotopes (CSSI) in fatty acids of possible sediment source areas to the stream in addition and compared them to SS from selected high flow and low flow events. Organic matter concentrations in the infiltrated and suspended sediment were highest during low flow periods with small sediment loads and lowest during high flow periods with high sediment loads. Peak values in nitrate and dissolved organic C were measured during high flow and high rainfall, probably due to leaching from pasture and arable land. The organic matter was of allochthonous sources as indicated by the C/N atomic ratio and δ13Corg. Organic matter in SS increased from up- to downstream due to an increase in sediment delivery from pasture and arable land downstream of the river. While the major sources of SS are pasture and arable land during base flow conditions, SS from forest soils increased during heavy rain events and warmer winter periods most likely due to snow melt which triggered erosion. Preliminary results of CSSI analysis of sediment source areas and comparison to SS of selected events indicate that differences in d13C values of individual fatty acids are too small to differentiate unambiguously between sediment sources.

Modelling the future impacts of climate and land-use change on suspended sediment transport in the River Thames (UK)

NASA Astrophysics Data System (ADS)

Bussi, Gianbattista; Dadson, Simon J.; Prudhomme, Christel; Whitehead, Paul G.

2016-11-01

The effects of climate change and variability on river flows have been widely studied. However the impacts of such changes on sediment transport have received comparatively little attention. In part this is because modelling sediment production and transport processes introduces additional uncertainty, but it also results from the fact that, alongside the climate change signal, there have been and are projected to be significant changes in land cover which strongly affect sediment-related processes. Here we assess the impact of a range of climatic variations and land covers on the River Thames catchment (UK). We first calculate a response of the system to climatic stressors (average precipitation, average temperature and increase in extreme precipitation) and land-cover stressors (change in the extent of arable land). To do this we use an ensemble of INCA hydrological and sediment behavioural models. The resulting system response, which reveals the nature of interactions between the driving factors, is then compared with climate projections originating from the UKCP09 assessment (UK Climate Projections 2009) to evaluate the likelihood of the range of projected outcomes. The results show that climate and land cover each exert an individual control on sediment transport. Their effects vary depending on the land use and on the level of projected climate change. The suspended sediment yield of the River Thames in its lowermost reach is expected to change by -4% (-16% to +13%, confidence interval, p = 0.95) under the A1FI emission scenario for the 2030s, although these figures could be substantially altered by an increase in extreme precipitation, which could raise the suspended sediment yield up to an additional +10%. A 70% increase in the extension of the arable land is projected to increase sediment yield by around 12% in the lowland reaches. A 50% reduction is projected to decrease sediment yield by around 13%.

Spatial patterns of streambed morphology around woody debris: flume experiments and field observations on the effects of woody debris on streambed morphology

NASA Astrophysics Data System (ADS)

Leung, V.; Montgomery, D. R.

2010-12-01

The interactions between woody debris, fluid flow and sediment transport in rivers play a fundamental role in ecogeomorphology, affecting channel roughness, streambed morphology, and sediment transport and storage. In particular, woody debris increases the hydraulic and topographic complexity in rivers, leading to a greater diversity of aquatic habitats and an increase in the number of large pools that are important fish habitat and breeding grounds. In the past decade, engineered logjams have become an increasingly used tool in river management for simultaneously decreasing the rate of riverbank migration and improving aquatic habitat. Sediment deposits around woody debris build up riverbanks and counteract bank migration caused by erosion. Previous experiments of flow visualization around model woody debris suggest the amount of sediment scour and deposition are primarily related to the presence of roots and the obstructional area of the woody debris. We present the results of field surveys and sediment transport experiments of streambed morphology around stationary woody debris on a mobile bed. These experiments test the effects of root presence, root geometry and log orientation of individual stationary trees on streambed morphology. The flume contains a deformable sediment bed of medium sand, and has subcritical and turbulent flow, corresponding to flow conditions found in nature. Field surveys on the Hoh River, WA, measure the local streambed morphology around woody debris (e.g. pool and gravel-bar length, width and depth), as well as woody debris characteristics (e.g. tree diameter, tree length, root diameter and root depth). We quantified the amount of local sediment scour and deposition around woody debris of varying sizes, geometries and orientations relative to flow. We find that: 1) the presence of roots on woody debris leads to greater areas of both sediment scour and deposition; and 2) the amount of sediment scour and deposition are related to the root cross-sectional area, oriented orthogonal to flow. Sediment transport around woody debris is episodic and occurs during flood events, making it difficult to take active measurements. A combined methodology of flume experiments and fieldwork allows for a general understanding of sediment transport around woody debris that includes the complexities of natural systems. A better understanding of the underlying sediment physics and hydraulics around naturally occurring woody debris in rivers can provide guidance and criteria for use in river restoration and engineering as well as scientific insights into a complex interdisciplinary problem.

Radionuclide contamination of sediment deposits in the Ob and Yenisey estuaries and areas of the Kara Sea.

PubMed

Standring, W J F; Stepanets, O; Brown, J E; Dowdall, M; Borisov, A; Nikitin, A

2008-04-01

The Ob and Yenisey rivers are major contributors to total riverine discharge to the Arctic Ocean. Several large nuclear facilities discharge into these rivers, which could affect actual and potential discharges of radionuclides to the Arctic region. This article presents new radionuclide concentration and grain-size data resulting from analyses of several sediment samples collected during research cruises in the Ob and Yenisey estuaries and adjacent areas during 2000 and 2001. Results indicate that discharges from the main nuclear facilities do not constitute a major contribution to the level of radioactive contamination in the marine areas studied, though Co-60 was detected at low concentrations in some sediment horizons. However, the aggregate contamination from different sources is not radioecologically significant in sediments within the study area, maximum Cs-137 levels being approximately 80 Bq kg(-1) dry weight.

Exposure to vancomycin causes a shift in the microbial community structure without affecting nitrate reduction rates in river sediments.

PubMed

Laverman, Anniet M; Cazier, Thibaut; Yan, Chen; Roose-Amsaleg, Céline; Petit, Fabienne; Garnier, Josette; Berthe, Thierry

2015-09-01

Antibiotics and antibiotic resistance genes have shown to be omnipresent in the environment. In this study, we investigated the effect of vancomycin (VA) on denitrifying bacteria in river sediments of a Waste Water Treatment Plant, receiving both domestic and hospital waste. We exposed these sediments continuously in flow-through reactors to different VA concentrations under denitrifying conditions (nitrate addition and anoxia) in order to determine potential nitrate reduction rates and changes in sedimentary microbial community structures. The presence of VA had no effect on sedimentary nitrate reduction rates at environmental concentrations, whereas a change in bacterial (16S rDNA) and denitrifying (nosZ) community structures was observed (determined by polymerase chain reaction-denaturing gradient gel electrophoresis). The bacterial and denitrifying community structure within the sediment changed upon VA exposure indicating a selection of a non-susceptible VA population.

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

PubMed

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

2017-08-15

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

Use of artificial stream mesocosms to investigate mercury uptake in the South River, Virginia, USA.

PubMed

Brent, Robert N; Berberich, David A

2014-02-01

Mercury is a globally distributed pollutant that biomagnifies in aquatic food webs. In the United States, 4,769 water bodies fail to meet criteria for safe fish consumption due to mercury bioaccumulation. Although the majority of these water bodies are affected primarily by atmospheric deposition of mercury, legacy contamination from mining or industrial activities also contribute to fish consumption advisories for mercury. The largest mercury impairment in Virginia, a 130-mile stretch of the South and South Fork Shenandoah rivers, is posted with a fish-consumption advisory for mercury contamination that originated from mercuric sulfate discharges from a textile facility in Waynesboro, Virginia, between 1929 and 1950. Although discharges of mercury to the river ceased >60 years ago, mercury levels in fish remain greater than levels safe for human consumption. This is due to the continued cycling of historic mercury in the river and its eventual uptake and biomagnification through aquatic food webs. This study investigated the relative importance of waterborne versus sediment-borne mercury in controlling biological uptake of mercury into the aquatic food web. Twelve artificial stream channels were constructed along the contaminated South River in Crimora, Virginia, and the uncontaminated North River in nearby Port Republic, Virginia, to provide four experimental treatments: a control with no Hg exposure, a Hg in sediment exposure, a Hg in water exposure, and a Hg in sediment and water exposure. After 6 weeks of colonization and growth, algae in each treatment was collected and measured for mercury accumulation. Mercury accumulation in water-only exposures was four times greater than in sediment-only exposures and was equivalent to accumulation in treatments with combined water and sediment exposure. This indicates that mercury in the water column is much more important in controlling biological uptake than mercury in near-field sediments. As a result, future remediation efforts need to focus on strategies that either remove mercury from the water column or decrease flux to the water column.

Simulation of Flow, Sediment Transport, and Sediment Mobility of the Lower Coeur d'Alene River, Idaho

USGS Publications Warehouse

Berenbrock, Charles; Tranmer, Andrew W.

2008-01-01

A one-dimensional sediment-transport model and a multi-dimensional hydraulic and bed shear stress model were developed to investigate the hydraulic, sediment transport, and sediment mobility characteristics of the lower Coeur d?Alene River in northern Idaho. This report documents the development and calibration of those models, as well as the results of model simulations. The one-dimensional sediment-transport model (HEC-6) was developed, calibrated, and used to simulate flow hydraulics and erosion, deposition, and transport of sediment in the lower Coeur d?Alene River. The HEC-6 modeled reach, comprised of 234 cross sections, extends from Enaville, Idaho, on the North Fork of the Coeur d?Alene River and near Pinehurst, Idaho, on the South Fork of the river to near Harrison, Idaho, on the main stem of the river. Bed-sediment samples collected by previous investigators and samples collected for this study in 2005 were used in the model. Sediment discharge curves from a previous study were updated using suspended-sediment samples collected at three sites since April 2000. The HEC-6 was calibrated using river discharge and water-surface elevations measured at five U.S. Geological Survey gaging stations. The calibrated HEC-6 model allowed simulation of management alternatives to assess erosion and deposition from proposed dredging of contaminated streambed sediments in the Dudley reach. Four management alternatives were simulated with HEC-6. Before the start of simulation for these alternatives, seven cross sections in the reach near Dudley, Idaho, were deepened 20 feet?removing about 296,000 cubic yards of sediments?to simulate dredging. Management alternative 1 simulated stage-discharge conditions from 2000, and alternative 2 simulated conditions from 1997. Results from alternatives 1 and 2 indicated that about 6,500 and 12,300 cubic yards, respectively, were deposited in the dredged reach. These figures represent 2 and 4 percent, respectively, of the total volume of dredged sediments removed before the start of simulation. In alternatives 3 and 4, the incoming total sediment discharges from the South Fork of the river were decreased by one-half. Management alternative 3 simulated stage-discharge conditions from 2000, and alternative 4 simulated conditions from 1997. Reducing incoming sediment discharge from the South Fork did not affect the streambed and deposition in the Dudley and downstream reaches, probably because the distance between the South Fork and the Dudley reach is long enough for sediment supply, transport capacity, and channel geometry to be balanced before reaching the Dudley and downstream reaches. Development and calibration of a multi-dimensional hydraulic and bed shear stress model (FASTMECH) allowed simulation of water-surface elevation, depth, velocity, bed shear stress, and sediment mobility in the Dudley reach (5.3 miles). The computational grid incorporated bathymetric and Light Detection and Ranging (LIDAR) data, with a node spacing of about 2.5 meters. With the exception of the fourth FASTMECH calibration simulation, results from the FASTMECH calibration simulations indicated that flow depths, flow velocities, and bed shear stresses increased as river discharge increased. Water-surface elevations in the fourth calibration simulation were about 2 feet higher than those in the other simulations because high lake levels in Coeur d?Alene Lake caused backwater conditions. Average simulated velocities along the thalweg ranged from about 3 to 5.3 feet per second, and maximum simulated velocities ranged from 3.9 to 7 feet per second. In the dredged reach, average simulated velocity along the thalweg ranged from 3.5 to 6 feet per second. The model also simulated several back-eddies (flow reversal); the largest eddy encompassed about one-third of the river width. Average bed shear stresses increased more than 200 percent from the first to the last simulation. Simulated sediment mobility, asses

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

NASA Astrophysics Data System (ADS)

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

2014-05-01

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

Suspended Sediment in the Indiana Harbor Canal and the Grand Calumet River, Northwestern Indiana, May 1996-June 1998

USGS Publications Warehouse

Renn, Danny E.

2000-01-01

Suspended-sediment samples and streamflow data were collected from May 1996 through June 1998 at three sites in the Grand Calumet River Basin - Indiana Harbor Canal at East Chicago, the east branch of the Grand Calumet River at Gary, and the west branch of the Grand Calumet River at Hammond. Sample analysis allowed for retention of sediments of 0.0015 millimeters or larger. At Indiana Harbor Canal at East Chicago, an automated sampler collected 2,005 suspended-sediment samples from the canal and, of these, 1,856 had associated streamflow values. To evaluate any bias between instream concentrations of suspended sediment and samples collected by the automated sampler, 27 sets of suspended-sediment samples were collected manually in the canal at the same time samples were collected by the automated sampler. There was no consistent bias between the samples collected manually instream and the samples collected by the automated sampler; therefore, no correction factor was applied to the concentrations of suspended sedment for the samples collected by the automated sampler. For the 2,005 and 1,856 samples, the mean suspended-sediment concentrations were the same, 15 milligrams per liter (mg/L), and the range in suspended-sediment concentrations were the same, from less than 1 mg/L to 97 mg/L. No apparent relation between the concentration of suspended sediment measured in samples from the Indiana Harbor Canal and streamflow was indicated, probably because of complex hydraulic conditions in the study area; most of the streamflow is from industrial and municipal discharges, and streamflow is affected by changes in water levels in Lake Michigan. There did appear to be a seasonal trend in the concentrations of suspended sediment, however, in that the largest concentrations generally were measured during the spring. During the study, four substantial rainfall events were recorded. Only for a rainfall event of 4.20 inches was there a substantial increase in the concentrations of suspended sediment and streamflow in the Indiana Harbor Canal. Six sets of samples were collected from the canal for determination of the percentage of organic material in the suspended sediment. Organic material in these samples averaged 26 percent. Bedload-sediment samples were collected three times in the canal with a bedload-sediment sampler; the collection-bag mesh size was 0.25 millimeter. No bedload sediments were collected in the sampler for any of the sample collections. Seven suspended-sediment samples were collected from the Grand Calumet River at Gary and at Hammond. The mean suspended sediment concentration measured in samples collected at Gary was 13 mg/L, and the mean suspended-sediment concentration measured in samples collected at Hammond was 6 mg/L. For both sites, there was no apparent relation between the concentration of suspended sediment and streamflow. Four suspended sediment samples were collected from the Grand Calumet River at Gary and at Hammond for determination of the percentage of organic material. The amount of organic material at Gary averaged 35 percent, and the amount of organic material at Hammond averaged 34 percent. The concentrations of suspended sediment determined for samples collected from the Indiana Harbor Canal and from the Grand Calumet River are less than concentrations of suspended sediment in samples collected from other streams in northwestern Indiana and in other parts of the State. Loads of suspended sediment were computed as the product of the weekly mean suspended-sediment concentration and the daily average streamflow for the Indiana Harbor Canal at East Chicago. The average suspended-sediment load computed for the canal was 29 tons per day for the first year of the study (June 1996 through May 1997) and 23 tons per day for the second year of the study (June 1997 through May 1998). Loads of suspended sediment for the Grand Calumet River at Gary and at Hammond were estimated by use of the ratin

Linking hyporheic flow and nitrogen cycling near the Willamette River - A large river in Oregon, USA

USGS Publications Warehouse

Hinkle, S.R.; Duff, J.H.; Triska, F.J.; Laenen, A.; Gates, E.B.; Bencala, K.E.; Wentz, D.A.; Silva, S.R.

2001-01-01

Several approaches were used to characterize ground water/surface water interactions near the Willamette River - A large (ninth order) river in Oregon, USA. A series of potentiometric surface maps demonstrated the presence of highly dynamic hydraulic gradients between rivers and the adjacent aquifer. Hyporheic zone gradients extended on the order of hundreds of meters. River gains and losses at the river stretch scale (tens of kilometers) were consistent with fluxes implied by the potentiometric surface maps, and apparently reflect regional ground water/surface water interactions. Gains and losses of up to 5-10% of streamflow were observed at this scale. On the river reach scale (1-2 km), gains and losses on the order of 5% of streamflow were interpreted as representing primarily local hyporheic exchange. Isotopic and chemical data collected from shallow hyporheic zone wells demonstrated interaction between regional ground water and river water. The origin of sampled hyporheic zone water ranged from a mixture dominated by regional ground water to water containing 100% river water. The common assumption that ground and river water mix primarily in the river channel is not applicable in this system. Isotopic and chemical data also indicated that significant (nearly complete) vegetative nitrate uptake and/or nitrate reduction occurred in water from 4 of 12 hyporheic zone sites. In these cases, it was primarily nitrate transported to the hyporheic zone in regional ground water that was removed from solution. Isotopes of water and nitrate indicated that hyporheic zone water sampled at two sites was composed of water originating as river water and demonstrated that significant vegetative nitrate uptake and nitrate reduction occurred along these hyporheic zone flowpaths. Thus, the hyporheic zone may, in some instances, serve to remove nitrate from river water. Additional investigations with chemical tools and microbial enzyme assays were conducted at one hyporheic site. A strong vertical redox gradient was observed, with nitrate-limited denitrification potential in deeper sediment and both nitrification and denitrification potential in shallower sediment. Since nitrogen cycling is strongly affected by redox conditions, nitrogen cycling in the hyporheic zone of this large-river system likely is affected by dynamics of ground water/surface water interactions that control fluxes of nitrogen and other redox species to hyporheic zone sediment.

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

NASA Astrophysics Data System (ADS)

Xu, K.; Yang, S. L.

2015-03-01

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

Discharge and sediment loads in the Boise River drainage basin, Idaho 1939-40

USGS Publications Warehouse

Love, S.K.; Benedict, Paul Charles

1948-01-01

The Boise River project is a highly developed agricultural area comprising some 520 square miles of valley and bench lands in southwestern Idaho. Water for irrigation is obtained from the Boise River and its tributaries which are regulated by storage in Arrow Rock and Deer Flat reservoirs. Distribution of water to the farms is effected by 27 principal canals and several small farm laterals which divert directly from the river. The- New York Canal, which is the largest, not only supplies water to smaller canals and farm laterals, but also is used to fill Deer Flat Reservoir near Nampa from which water is furnished to farms in the lower valley. During the past 15 years maintenance costs in a number of those canals have increased due to deposition of sediment in them and in the river channel itself below the mouth of Moore Creek. Interest in determining the runoff and sediment loads from certain areas in the Boise River drainage basin led to an investigation by the Flood Control Coordinating Committee of the Department of Agriculture. Measurements of daily discharge and sediments loads were made by the Geological Survey at 13 stations in the drainage basin during the 18-month period ended June 30, 1940. The stations were on streams in areas having different kinds of vegetative cover and subjected to different kinds of land-use practice. Data obtained during the investigation furnish a basis for certain comparisons of runoff and sediment loads from several areas arid for several periods of time. Runoff measured at stations on the. Boise River near Twin Springs and on Moore Creek near Arrow Rock was smaller during 1939 than during 1940 and was below the average annual runoff for the period of available record. Runoff measured at the other stations on the project also was smaller during 1939 than during 1940 and probably did not exceed the average for the previous 25 years. The sediment loads measured during the spring runoff in 1939 were smaller at most stations than those measured during the spring runoff in 1940. At those stations where the flow was not affected, or only slightly affected, by upstream diversions or by placer-mining operations, the largest sadiment loads per unit of drainage area were measured in Grouse Creek during both 1939 and 1940, amounting to 3,460 and 2,490 tons per square mile, respectively, and the smallest loads per unit of drainage area were measured in Bannock Creek during 1939 and in the Boise River near Twin Springs during 1940, amounting to 14 and 83 tons per square mile, respectively. Size anaylses of a large number of samples of suspended and deposited sediments give an indication of the origin of sediments carried past some of the stations. The analyses show that most of the sediment measured at the five stations in the Moore Creek drainages basin above Idaho City consisted largely of coarse material. They show, also, that the sediment measured at the station on Moore Creek above Thorn Creek consisted almost entirely of fine material during practically the entire period of the investigation. Most of the coarse material passing the stations above Idaho City probably was retained behind the dikes or in the pools usually formed by tailings from dredging operations in the placer-mining area below Idaho City, and much of the fine material measured at the station on Moore Creek above Thorn Creek probably was contributed by placer-mining activity. During the years when the spring runoff is greater than that measured during 1939 and 1940, it is probable that the dikes and pools will be less effective in retaining coarse sediments within the placered area. Records of sediment loads measured in the New York Canal indicate that a negligible amount of sediment was deposited there during 1939, but that in 1940 from 10 to 15 percent of the total load at the gaging station consisted of coarse sediment which was later deposited on the canal bottom. Most of the fine material was doubtless carried through the canal and eventually deposited in diversion ditches and on farm land. Because the sediment carried past the station on Moore Creek above Thorn Creek consisted almost entirely of fine material, it is probable, that a considerable part of the coarse sediment carried in the New York Canal during the 1940 spring runoff period was scoured from the large bed of deposited material in the Boise River above Diversion- Dam, and that the remainder came from Grimes Creek. Arrow Rock Reservoir was not sluiced during the investigation, and it is therefore unlikely that any of the coarse sediment in the New York Canal came from the Boise River above Moore Creek during 1939 and 1940. The average dry weight of 71 samples of deposited sediments collected from several parts of the Boise River drainage basin is about 90 pounds per cubic foot. The average specific gravity of 77 samples of deposited sediments is 2.57.

Modeling and analysis of Soil Erosion processes by the River Basins model: The Case Study of the Krivacki Potok Watershed, Montenegro

NASA Astrophysics Data System (ADS)

Vujacic, Dusko; Barovic, Goran; Mijanovic, Dragica; Spalevic, Velibor; Curovic, Milic; Tanaskovic, Vjekoslav; Djurovic, Nevenka

2016-04-01

The objective of this research was to study soil erosion processes in one of Northern Montenegrin watersheds, the Krivacki Potok Watershed of the Polimlje River Basin, using modeling techniques: the River Basins computer-graphic model, based on the analytical Erosion Potential Method (EPM) of Gavrilovic for calculation of runoff and soil loss. Our findings indicate a low potential of soil erosion risk, with 554 m³ yr-1 of annual sediment yield; an area-specific sediment yield of 180 m³km-2 yr-1. The calculation outcomes were validated for the entire 57 River Basins of Polimlje, through measurements of lake sediment deposition at the Potpec hydropower plant dam. According to our analysis, the Krivacki Potok drainage basin is with the relatively low sediment discharge; according to the erosion type, it is mixed erosion. The value of the Z coefficient was calculated on 0.297, what indicates that the river basin belongs to 4th destruction category (of five). The calculated peak discharge from the river basin was 73 m3s-1 for the incidence of 100 years and there is a possibility for large flood waves to appear in the studied river basin. Using the adequate computer-graphic and analytical modeling tools, we improved the knowledge on the soil erosion processes of the river basins of this part of Montenegro. The computer-graphic River Basins model of Spalevic, which is based on the EPM analytical method of Gavrilovic, is highly recommended for soil erosion modelling in other river basins of the Southeastern Europe. This is because of its reliable detection and appropriate classification of the areas affected by the soil loss caused by soil erosion, at the same time taking into consideration interactions between the various environmental elements such as Physical-Geographical Features, Climate, Geological, Pedological characteristics, including the analysis of Land Use, all calculated at the catchment scale.

The changing hydro-ecological dynamics of rivers and deltas of the Western Indian Ocean: Anthropogenic and environmental drivers, local adaptation and policy response

NASA Astrophysics Data System (ADS)

Duvail, Stéphanie; Hamerlynck, Olivier; Paron, Paolo; Hervé, Dominique; Nyingi, Wanja D.; Leone, Michele

2017-10-01

The rivers flowing into the Western Indian Ocean have steep headwater gradients and carry high sediment loads. In combination with strong tides and seasonal rainfall, these rivers create dynamic deltas with biodiversity-rich and productive ecosystems that, through flooding, have sustained indigenous use systems for centuries. However, river catchments are rapidly changing due to deforestation. Hydropower dams also increasingly alter flood characteristics, reduce sediment supply and contribute to coastal erosion. These impacts are compounded by climate change. Altogether, these changes affect the livelihoods of the delta users. Here, based on prior works that we and others have conducted in the region, we analyse the drivers of these hydro-ecological changes. We then provide recommendations for improved dam design and operations to sustain the underlying delta-building processes, the ecosystem values and the needs of the users.

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

High-alpine environments are strongly affected by glacier retreat since the Little Ice Age (LIA). Due to ongoing climate change the hydrology of proglacial rivers is also influenced. It is expected that the growing proportions of snow melt and rainfall events will change runoff characteristics of proglacial rivers. Additionally, the importance of paraglacial sediment sources in recently deglaciating glacier forefields is increasing, while the role of glacial erosion is declining. Thus complex environmental conditions leading to a complex pattern of fluvial sediment transport in partly glaciated catchments of the European Alps. Under the umbrella of the joint PROSA-project the fluvial sediment transport of the river Riffler Bach (Kaunertal, Tyrol, Austria) was studied in 3 consecutive ablation seasons in order to quantify sediment yields. In June 2012 a probe for water level and an automatic water sampler (AWS) were installed at the outlet of the catchment (20km2). In order to calculate annual stage-discharge-relations by the rating-curve approach, discharge (Q) was repeatedly measured with current meters and by salt dilution. Concurrent to the discharge measurements bed load was collected using a portable Helley-Smith sampler. Bed load samples were weighted and sieved in the laboratory to gain annual bed load rating curves and grain size distributions. In total 564 (2012: 154, 2013: 209, 2014: 201) water samples were collected and subsequently filtered to quantify suspended sediment concentrations (SSC). Q-SSC-relations were calculated for single flood events due to the high variability of suspended sediment transport. The results show a high inter- and intra-annual variability of solid fluvial sediment transport, which can be explained by the characteristics of suspended sediment transport. Only 13 of 22 event-based Q-SSC-relations show causal dependency. In 2012, during a period with multiple pluvial-induced peak discharges most sediment was transported. On the contrary the importance of snow melt for sediment transport was indicated during the ablation season 2013. In total 3582 t of sediment were exported out of the Riffler Bach catchment in 2012, which is almost twice the solid sediment load of the ablation season 2013 (1953 t). Total solid load of the Riffler Bach River was 3511 t in 2014 Suspended sediment load was dominant in all ablation seasons. The result of additional DEM analysis reveals that 37 % of the catchment do not contribute or only contribute to a lesser amount to the fluvial sediment export out of the catchment. The findings of the grain size analysis imply glacigenic origin of the transported particles. Thus, the results indicate that solid sediment transport is not only a function of discharge. Also availability of sediment and the systems state of (dis-)connectivity, e.g. coupling of sediment sources to the river, need to be considered.

Characterizing relationships among fecal indicator bacteria, microbial source tracking markers, and associated waterborne pathogen occurrence in stream water and sediments in a mixed land use watershed

USDA-ARS?s Scientific Manuscript database

Bed sediments of streams and rivers may store high concentrations of fecal indicator bacteria (FIB) and pathogens. These contaminants can be mobilized into the water column due to resuspension events, thus affecting overall water quality. Along with the contaminants, other markers such as microbia...

Quantifying and identifying the sources of fine sediment input in a typical Mongolian river basin, the Kharaa River case study

NASA Astrophysics Data System (ADS)

Theuring, Phillip

2013-04-01

Mongolia is facing a tremendous change of land-use intensification due to expansions in the agricultural sector, an increase of cattle and livestock and a growth of urban settlements by migration of the rural population to the cities. With most of its area located in a semiarid to arid environment, Mongolia is vulnerable to climatic changes that are expected to lead to higher temperatures and increased evapotranspiration. It is expected that this may lead to unfavorable changes in surface water quality caused by increased nutrients and sediment bound pollutants emissions. Increased fine sediment load is associated with nutrient, heavy metal and pollutant input and therefore affects water quality. Previous studies using radionuclide fallout isotope sediment source fingerprinting investigations identified riverbank erosion as the main source of suspended sediment in the Kharaa River. Erosion susceptibility calculations in combination with suspended sediment observations showed strong seasonal and annual variabilities of sediment input and in-stream transport, and a strong connection of erosional behaviour with land-use.The objective of this study is to quantify the current water quality threats by fine sediment inputs in the 15,000 km2 Kharaa River basin in Northern Mongolia by delineating the sources of the fine sediments and estimating the sediment budget.To identify the spatial distribution of sediment sources within the catchment, more than 1000 samples from the river confluences at the outlet of each sub basin into the main tributary were collected during 5 intensive grab sediment sampling campaigns in 2009-11. The fine sediment fraction (<10μm) has been analysed using geochemical tracer techniques for spatial source identification, based on major elements (e.g. Si, Al, Mg, Fe, Na, K, P) and trace elements (e.g. Ba, Pb, Sr, Zn). The contribution of suspended sediment of each sub basin in the main tributary has been evaluated with help of a mixing model. To asses sediment sources the RUSLE based sediment budget model (SedNet) was employed to estimate surface erosion and sediment budget. The spatial origin of the fine sediment in the catchment could be identified by geochemical fingerprinting techniques. This shows that only some subcatchments contribute considerably to the fine sediment load, especially areas with high grazing intensity and degraded riparian vegetation. The estimated average soil loss in the catchment is 0.2 t×ha-1•a-1. The model results reveal a strong influence of the landuse in the catchment on surface erosion and fine sediment input, which will increase with the intensification of agriculture in the catchment.

Microbial responses to polycyclic aromatic hydrocarbon contamination in temporary river sediments: Experimental insights.

PubMed

Zoppini, Annamaria; Ademollo, Nicoletta; Amalfitano, Stefano; Capri, Silvio; Casella, Patrizia; Fazi, Stefano; Marxsen, Juergen; Patrolecco, Luisa

2016-01-15

Temporary rivers are characterized by dry-wet phases and represent an important water resource in semi-arid regions worldwide. The fate and effect of contaminants have not been firmly established in temporary rivers such as in other aquatic environments. In this study, we assessed the effects of sediment amendment with Polycyclic Aromatic Hydrocarbons (PAHs) on benthic microbial communities. Experimental microcosms containing natural (Control) and amended sediments (2 and 20 mg PAHs kg(-1) were incubated for 28 days. The PAH concentrations in sediments were monitored weekly together with microbial community structural (biomass and phylogenetic composition by TGGE and CARD-FISH) and functional parameters (ATP concentration, community respiration rate, bacterial carbon production rate, extracellular enzyme activities). The concentration of the PAH isomers did not change significantly with the exception of phenanthrene. No changes were observed in the TGGE profiles, whereas the occurrence of Alpha- and Beta-Proteobacteria was significantly affected by the treatments. In the amended sediments, the rates of carbon production were stimulated together with aminopeptidase enzyme activity. The community respiration rates showed values significantly lower than the Control after 1 day from the amendment then recovering the Control values during the incubation. A negative trend between the respiration rates and ATP concentration was observed only in the amended sediments. This result indicates a potential toxic effect on the oxidative phosphorylation processes. The impoverishment of the energetic resources that follows the PAH impact may act as a domino on the flux of energy from prokaryotes to the upper level of the trophic chain, with the potential to alter the temporary river functioning.

Linking the historic 2011 Mississippi River flood to coastal wetland sedimentation

USGS Publications Warehouse

Falcini, Federico; Khan, Nicole S.; Macelloni, Leonardo; Horton, Benjamin P.; Lutken, Carol B.; McKee, Karen L.; Santoleri, Rosalia; Colella, Simone; Li, Chunyan; Volpe, Gianluca; D’Emidio, Marco; Salusti, Alessandro; Jerolmack, Douglas J.

2012-01-01

Wetlands in the Mississippi River deltaic plain are deteriorating in part because levees and control structures starve them of sediment. In Spring of 2011 a record-breaking flood brought discharge on the lower Mississippi River to dangerous levels, forcing managers to divert up to 3500 m3/s-1 of water to the Atchafalaya River Basin. Here we quantify differences between the Mississippi and Atchafalaya River inundation and sediment-plume patterns using field-calibrated satellite data, and assess the impact these outflows had on wetland sedimentation. We characterize hydrodynamics and suspended sediment patterns of the Mississippi River plume using in-situ data collected during the historic flood. We show that the focused, high-momentum jet from the leveed Mississippi delivered sediment far offshore. In contrast, the plume from the Atchafalaya was more diffuse; diverted water inundated a large area; and sediment was trapped within the coastal current. Maximum sedimentation (up to several centimetres) occurred in the Atchafalaya Basin despite the larger sediment load carried by the Mississippi. Minimum accumulation occurred along the shoreline between these river sources. Our findings provide a mechanistic link between river-mouth dynamics and wetland sedimentation patterns that is relevant for plans to restore deltaic wetlands using artificial diversions.

Sediment load from major rivers into Puget Sound and its adjacent waters

USGS Publications Warehouse

Czuba, Jonathan A.; Magirl, Christopher S.; Czuba, Christiana R.; Grossman, Eric E.; Curran, Christopher A.; Gendaszek, Andrew S.; Dinicola, Richard S.

2011-01-01

Each year, an estimated load of 6.5 million tons of sediment is transported by rivers to Puget Sound and its adjacent waters—enough to cover a football field to the height of six Space Needles. This estimated load is highly uncertain because sediment studies and available sediment-load data are sparse and historically limited to specific rivers, short time frames, and a narrow range of hydrologic conditions. The largest sediment loads are carried by rivers with glaciated volcanoes in their headwaters. Research suggests 70 percent of the sediment load delivered to Puget Sound is from rivers and 30 percent is from shoreline erosion, but the magnitude of specific contributions is highly uncertain. Most of a river's sediment load occurs during floods.

Managed flood effects on beaver pond habitat in a desert riverine ecosystem, bill williams river, Arizona USA

USGS Publications Warehouse

Andersen, D.C.; Shafroth, P.B.; Pritekel, C.M.; O'Neill, M. W.

2011-01-01

The ecological effects of beaver in warm-desert streams are poorly documented, but potentially significant. For example, stream water and sediment budgets may be affected by increased evaporative losses and sediment retention in beaver ponds. We measured physical attributes of beaver pond and adjacent lotic habitats on a regulated Sonoran Desert stream, the Bill Williams River, after ???11 flood-free months in Spring 2007 and Spring 2008. Neither a predicted warming of surface water as it passed through a pond nor a reduction in dissolved oxygen in ponds was consistently observed, but bed sediment sorted to finest in ponds as expected. We observed a river segment-scale downstream rise in daily minimum stream temperature that may have been influenced by the series of ??100 beaver ponds present. Channel cross-sections surveyed before and after an experimental flood (peak flow 65 m3/s) showed net aggradation on nine of 13 cross-sections through ponds and three of seven through lotic reaches. Our results indicate that beaver affect riverine processes in warm deserts much as they do in other biomes. However, effects may be magnified in deserts through the potential for beaver to alter the stream thermal regime and water budget. ?? Society of Wetland Scientists 2011.

Multi-timescale sediment responses across a human impacted river-estuary system

NASA Astrophysics Data System (ADS)

Chen, Yining; Chen, Nengwang; Li, Yan; Hong, Huasheng

2018-05-01

Hydrological processes regulating sediment transport from land to sea have been widely studied. However, anthropogenic factors controlling the river flow-sediment regime and subsequent response of the estuary are still poorly understood. Here we conducted a multi-timescale analysis on flow and sediment discharges during the period 1967-2014 for the two tributaries of the Jiulong River in Southeast China. The long-term flow-sediment relationship remained linear in the North River throughout the period, while the linearity showed a remarkable change after 1995 in the West River, largely due to construction of dams and reservoirs in the upland watershed. Over short timescales, rainstorm events caused the changes of suspended sediment concentration (SSC) in the rivers. Regression analysis using synchronous SSC data in a wet season (2009) revealed a delayed response (average 5 days) of the estuary to river input, and a box-model analysis established a quantitative relationship to further describe the response of the estuary to the river sediment input over multiple timescales. The short-term response is determined by both the vertical SSC-salinity changes and the sediment trapping rate in the estuary. However, over the long term, the reduction of riverine sediment yield increased marine sediments trapped into the estuary. The results of this study indicate that human activities (e.g., dams) have substantially altered sediment delivery patterns and river-estuary interactions at multiple timescales.

Cambrian rivers and floodplains: the significance of microbial cementation, groundwater and aeolian sediment transport

NASA Astrophysics Data System (ADS)

Reesink, A. J. H.; Best, J.; Freiburg, J. T.; Nathan, W.

2016-12-01

Rivers that existed before land plants colonized the Earth are commonly considered to be unaffected by microbial activity on their floodplains, because the limited cementation produced by microbial activity is insufficient to stabilize the river banks. Although this assumption is likely correct, such emphasis on channel dynamics ignores the potential role of floodplain dynamics as an integral component of the river system. Detailed analysis of cores from the Cambrian Mount Simon Sandstone, Illinois, suggests that a significant proportion of the terrestrial sequence is composed of flat-bedded `crinkly' structures that provide evidence of cementation by soil crusts and microbial biofilms, and that promoted the adhesion of sediment to sticky surfaces. Wind ripples and local desert pavements were abundant. These findings highlight that sediment deposition on Cambrian floodplains was often dominated by wind in locations where the ground water table reached the surface, and was thus likely independent of sediment transport within the river channel. Erosion by wind would thus have been hindered by surface cementation and the formation of desert pavements. Such ground water control on deposition, and resistance to erosion by floodplain surface hardening, appear to have been the primary controls on Cambrian floodplain topography. Because floodplain topography poses a key control on channel and floodplain flow, these processes may have affected patterns of erosion and deposition, as well as reach-scale dynamics such as channel avulsions. The autonomous operation of wind-and-groundwater controlled floodplains makes pre-vegetated river systems more sensitive to climatic conditions such as precipitation and evaporation, and strikingly different from those that occurred after the development of land plants.

Sources, dispersal, and fate of fine sediment supplied to coastal California

USGS Publications Warehouse

Farnsworth, Katherine L.; Warrick, Jonathan A.

2007-01-01

We have investigated the sources, dispersal, and fate of fine sediment supplied to California coastal waters in a partnership between the U.S. Geological Survey (USGS) and the California Sediment Management Workgroup (CSMW). The purpose of this study was to document the rates and characteristics of these processes so that the State can better manage its coastal resources, including sediment. In this study, we made the following observations: - Rivers dominate the supply of fine sediment to the California coastal waters, with an average annual flux of 34 megatonnes (Mt). - Cliff and bluff erosion in central and southern California is a source of fine sediment, with a delivery rate of approximately 10 percent of river loads. In the southern most part of the State, however, where river-sediment loads are low, cliff and bluff erosion represent approximately 40 percent of the total fine-sediment flux. - Temporal variation in the sources of fine sediment is high. River floods and bluff erosion are episodic and dominated by winter storms, which supply most sediment flux to the coast. The magnitude of winter storms is generally related to the El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) climate cycles. - The three rivers that dominate fine-sediment flux to the California coast are the Eel, Salinas, and Santa Clara Rivers. Because the sediment delivery from these and all other California coastal watersheds is episodic, individual rivers discharge most of their annual loads over the course of only a few days per year. - Spatial variation in river-sediment discharge is high and generally related to such watershed characteristics as geology, precipitation, and drainage area. For example, the Transverse Range of southern California represents only 9 percent of the watershed-drainage area but 18 percent of the fine-sediment flux, a function of the young sedimentary bedrock and active tectonics of this region. The urban rivers of southern California were observed to discharge sediment at rates consistent with those of the surrounding Transverse Range rivers, which share the same geologic setting. - Direct observations of fine-sediment dispersal have been limited to the river-mouth settings of the Eel and Santa Clara Rivers, where sediment has been observed to settle quickly from buoyant plumes and be transported along the seabed during periods of storm waves. - After heavy loading of fine sediment onto the continental shelf during river floods, there is increasing evidence that fluid-mud gravity flows occur within a layer 10 to 50 cm above the seabed and efficiently transport fine sediment offshore. - All along the California coast, the timing of river discharge and coastal winds and waves from storm events are strongly coherent; however, of large wave events with the potential for resuspending and transporting fine sediment occur during periods without significant rainfall and therefore no significant river discharge. - Although fine sediment dominates the midshelf mud belts offshore of California river mouths, these mud belts are not the dominant sink of fine sediment, much of which is deposited across the entire continental shelf, including the inner shelf, and offshelf into deeper water depths. - Accumulation rates of fine sediment, which can exceed several millimeters per year, are generally highest near river sources of sediment and along the inner shelf and midshelf. - Sediment-accumulation rates, as summarized from both long-term and recent investigations of continental-shelf geochronology, are generally consistent across California except in southern California, where recently the sediment-accumulation rate has been tenfold greater than the long-term rate, possibly as a result of increased river discharge, wastewater outfall inputs, or other anthropogenic sources. Thus, fine sediment is a natural and dynamic element of the California coastal system because of large, natural sediment sources and dynamic transport processes.

Calculating the spatio-temporal variability of bedrock exposure on seasonal hydrograph timescales as a prerequisite to modeling bedrock river evolution

NASA Astrophysics Data System (ADS)

Hurst, A. A.; Anderson, R. S.; Tucker, G. E.

2017-12-01

Erosion of bedrock river channels exerts significant control on landscape evolution because it communicates climatic and tectonic signals across a landscape by setting the lower erosional boundaries for hillslopes. Hillslope erosion delivers sediment to the channels, which then either store or transport the sediment. At times of high storage, access to the bedrock floor of the channel is limited, inhibiting bedrock erosion. This affects the timescale of channel response to imposed base-level lowering, which in turn affects hillslope erosion. Because occasional exposure of the bedrock bed is a minimum prerequisite for bedrock erosion, we seek to understand the evolution of sediment cover, or scour history, with sufficient resolution to answer when and where the bed is exposed. The scour history at a site is governed by grain size, bed and channel morphology, sediment concentration in the water, and seasonal flow conditions (hydrograph). The transient nature of bedrock exposure during high-flow events implies that short-term sediment cover dynamics are important for predicting long-term bedrock incision rates. Models of channel profile evolution, or of landscape evolution, generally ignore evolution of sediment cover on the hydrograph timescale. To develop insight into the necessary and sufficient conditions for bedrock exposure followed by reburial, we have developed a 1-D model of the evolution of alluvial cover thickness in a long channel profile in response to a seasonal hydrograph. This model tracks erosion, deposition, and the concentration of sediment in the water column separately, and generates histories of scour and fill over the course of the hydrograph. We compare the model's predictions with net-scour measurements in tributaries of the Grand Canyon and with scour-chain and accelerometer measurements in the Cedar River, Washington. By addressing alluvial scour on short timescales, we acknowledge the processes required to allow bedrock incision and landscape evolution over longer timescales.

Spatial variation of sediment mineralization supports differential CO2 emissions from a tropical hydroelectric reservoir.

PubMed

Cardoso, Simone J; Vidal, Luciana O; Mendonça, Raquel F; Tranvik, Lars J; Sobek, Sebastian; Fábio, Roland

2013-01-01

Substantial amounts of organic matter (OM) from terrestrial ecosystems are buried as sediments in inland waters. It is still unclear to what extent this OM constitutes a sink of carbon, and how much of it is returned to the atmosphere upon mineralization to carbon dioxide (CO2). The construction of reservoirs affects the carbon cycle by increasing OM sedimentation at the regional scale. In this study we determine the OM mineralization in the sediment of three zones (river, transition, and dam) of a tropical hydroelectric reservoir in Brazil as well as identify the composition of the carbon pool available for mineralization. We measured sediment organic carbon mineralization rates and related them to the composition of the OM, bacterial abundance and pCO2 of the surface water of the reservoir. Terrestrial OM was an important substrate for the mineralization. In the river and transition zones most of the OM was allochthonous (56 and 48%, respectively) while the dam zone had the lowest allochthonous contribution (7%). The highest mineralization rates were found in the transition zone (154.80 ± 33.50 mg C m(-) (2) d(-) (1)) and the lowest in the dam (51.60 ± 26.80 mg C m(-) (2) d(-) (1)). Moreover, mineralization rates were significantly related to bacterial abundance (r (2) = 0.50, p < 0.001) and pCO2 in the surface water of the reservoir (r (2) = 0.73, p < 0.001). The results indicate that allochthonous OM has different contributions to sediment mineralization in the three zones of the reservoir. Further, the sediment mineralization, mediated by heterotrophic bacteria metabolism, significantly contributes to CO2 supersaturation in the water column, resulting in higher pCO2 in the river and transition zones in comparison with the dam zone, affecting greenhouse gas emission estimations from hydroelectric reservoirs.

Source identification and ecological impact evaluation of PAHs in urban river sediments: A case study in Taiwan.

PubMed

Tu, Y T; Ou, J H; Tsang, D C W; Dong, C D; Chen, C W; Kao, C M

2018-03-01

The Love River and Ho-Jin River, two major urban rivers in Kaohsiung City, Taiwan, are moderately to heavily polluted because different types of improperly treated wastewaters are discharged into the rivers. In this study, sediment and river water samples were collected from two rivers to investigate the river water quality and accumulation of polycyclic aromatic hydrocarbons (PAHs) in sediments. The spatial distribution, composition, and source appointment of PAHs of the sediments were examined. The impacts of PAHs on ecological system were assessed using toxic equivalence quotient (TEQ) of potentially carcinogenic PAHs (TEQ carc ) and sediment quality guidelines. The average PAHs concentrations ranged from 2161 ng/g in Love River sediment to 160 ng/g in Ho-Jin River sediment. This could be due to the fact that Love River Basin had much higher population density and pyrolytic activities. High-ring PAHs (4-6 rings) contributed to 59-90% of the total PAHs concentrations. Benzo(a)pyrene (BaP) had the highest toxic equivalence quotient (up to 188 ng TEQ/g). Moreover, the downstream sediments contained higher TEQ of total TPHs than midstream and upstream sediment samples. The PAHs were adsorbed onto the fine particles with high organic content. Results from diagnostic ratio analyses indicate that the PAHs in two urban river sediments might originate from oil/coal combustion, traffic-related emissions, and waste combustion (pyrogenic activities). Future pollution prevention and management should target the various industries, incinerators, and transportation emission in this region to reduce the PAHs pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Event-based washload transport and sedimentation in and around flood bypasses: Case study from the Sacramento Valley, California

NASA Astrophysics Data System (ADS)

Singer, M. B.; Aalto, R. A.

2005-05-01

In large river systems, suspended sediment transport and deposition patterns are often affected by channel constraints engineered for flood conveyance or navigation. Such managed channels typically have a limited number of overflow loci through which suspended sediment enters the river's floodplain. Engineered flood bypasses are narrow relic floodplains that are supplied by overflow diversion weirs along managed river channels, and support agriculture and complex aquatic and riparian habitats that are sensitive to the delivery of floods, fine sediment, and adsorbed contaminants. They function as wide, shallow conveyance channels parallel to the main river, and therefore present an opportunity to assess the applicability of existing theory for delivery to and settling of suspended sediment within floodplains. This study is an investigation of hydrograph characteristics, sediment delivery, and sedimentation within the upstream reaches of flood bypasses closest to the weir. We present analysis of hydrologic and sediment records and modeling in the Sacramento River basin. The effects of a single large flood in 1964-1965 were analyzed by documenting hydrograph characteristics, computing event-based sediment discharges and reach erosion/deposition through the bypass system, modeling bypass deposition, and comparing modeled results near the weirs with dated sediment cores. The rapidly rising, slowly declining 1964 flood was generated by storm runoff in the Sierra Nevada. The modeling results indicate: washload discharge through the lower valley 0.5 to 1.7 times long-term annual averages; mainstem reach erosion/deposition 0.5 to 1.25 times annual averages; and centimeter scale deposition in flood bypasses. The results are corroborated by a set of sediment cores extracted from Sacramento Valley bypasses, which were dated with 210Pb geochronology and analyzed for grain size. The modeling and data suggest net sediment accumulation between the channel and flood weirs and in the `hydraulic shadow' of the flood weir, the length of which varies depending on flow and sediment characteristics. Net accumulation in the hydraulic shadow is hypothesized to be associated with infrequent, episodic erosion of stored upland mining legacy sediments. As a result, more frequent, relatively clear-water flooding erodes prior bypass sediment deposits at the downstream end of the hydraulic shadow and propagates upstream toward the weir. Such sediment remobilization and scour events were extensively documented in our cores and have implications for the fate and transport of contaminants such as mercury, left over from decades of foothill mining, and for sediment and contaminant delivery to the Sacramento-San Francisco Bay-Delta. The modeling and field data highlighted shortcomings in conventional theory for event-based sediment concentration profiles and particle settling. These limitations could be addressed with appropriate data collection and model revision to account for the processes of sediment transport over weirs and into flood conveyance channels.

Modern Environmental Changes on Amapa Coastal Plain under Amazon River Influence

NASA Astrophysics Data System (ADS)

Santos, V. F.; Figueiredo, A. G.; Silveira, O. M.; Polidori, L.

2007-05-01

The Amazonian coastal environment is very dynamic compared to other coasts. It is situated at the edge of the Earth's largest forest, and is segmented by fluvial systems, with the biggest being the Amazon River. The rivers are particularly influenced by the Intertropical Convergence Zone (ITCZ), which controls the water and particle discharge, and the flooding regime. Moderate and strong El Nino conditions correlate with low-precipitation periods, and La Nina events cause precipitation to increase. These variables and others related to the Amazon dispersal system create an interesting area for the study of global and regional environmental changes. The Araguari River floodplain on the Amapa coast is influenced by natural processes of global scale such as ENSO events and ITCZ, and by local processes such as Amazon River discharge, tides and tidal bore (pororoca). Anthropogenic processes such as extensive water-buffalo farming also promote environmental changes. Time- series analyses of remote sensing images and suspended sediment have shown that the maximum turbidity zone inside Araguari River is related to the pororoca phenomenon. The pororoca remobilizes sediment from the river bottom and margins, developing sediment suspension >15 g/l as it passes - creating fluid muds. The pororoca also introduces Amazon- and shelf-derived sediment into the Araguari estuary. Measurements during eight spring-tide cycles indicate erosion of 3 cm of consolidated mud and deposition of 1 cm. The pororoca also influences the remobilization and cycling of nutrients and consequently affects the distribution of benthic organisms, including benthonic foraminifera and thecamoebians. For more than a century, the coastal plain has had water-buffalo farming (>42,000 animals today), which modifies the drainage system and affects sedimentary processes. Areas with more buffalo trails have higher suspended-sediment concentration (SSC) during the dry season and lower SSC during the rainy season. This relationship is reversed in drainages without the influence of the herd. The development of small channels, one meter deep by one meter wide, induced by the buffalos can evolve into a large drainage network in a short period of time. The Santana Creek started as a buffalo trail and in three decades it evolved into a network with a main channel 200 m wide and 6 km long. Despite the Amazon River having the largest influence in the region, the Araguari River also has a considerable water discharge of 2.4x103 m3/s and particulate discharge of 7x105 tons/y, and is able to impose changes to the Amapa coastal environments and inner shelf. The natural closure of the Araguari north arm during middle of the 19th century has induced the development of a wide coastal plain in the Cape Norte region, and decreased fresh water to the Carapaporis channel. On the other hand, deforestation for farm development and buffalo farming has influenced the hydrologic regime, sediment and nutrient balance.

Patterns of floodplain sediment deposition along the regulated lower Roanoke River, North Carolina: annual, decadal, centennial scales

USGS Publications Warehouse

Hupp, Cliff R.; Schenk, Edward R.; Kroes, Daniel; Willard, Debra A.; Townsend, Phil A.; Peet, Robert K.

2015-01-01

The lower Roanoke River on the Coastal Plain of North Carolina is not embayed and maintains a floodplain that is among the largest on the mid-Atlantic Coast. This floodplain has been impacted by substantial aggradation in response to upstream colonial and post-colonial agriculture between the mid-eighteenth and mid-nineteenth centuries. Additionally, since the mid-twentieth century stream flow has been regulated by a series of high dams. We used artificial markers (clay pads), tree-ring (dendrogeomorphic) techniques, and pollen analyses to document sedimentation rates/amounts over short-, intermediate-, and long-term temporal scales, respectively. These analyses occurred along 58 transects at 378 stations throughout the lower river floodplain from near the Fall Line to the Albemarle Sound. Present sediment deposition rates ranged from 0.5 to 3.4 mm/y and 0.3 to 5.9 mm/y from clay pad and dendrogeomorphic analyses, respectively. Deposition rates systematically increased from upstream (high banks and floodplain) to downstream (low banks) reaches, except the lowest reaches. Conversely, legacy sediment deposition (A.D. 1725 to 1850) ranged from 5 to about 40 mm/y, downstream to upstream, respectively, and is apparently responsible for high banks upstream and large/wide levees along some of the middle stream reaches. Dam operations have selectively reduced levee deposition while facilitating continued backswamp deposition. A GIS-based model predicts 453,000 Mg of sediment is trapped annually on the floodplain and that little watershed-derived sediment reaches the Albemarle Sound. Nearly all sediment in transport and deposited is derived from the channel bed and banks. Legacy deposits (sources) and regulated discharges affect most aspects of present fluvial sedimentation dynamics. The lower river reflects complex relaxation conditions following both major human alterations, yet continues to provide the ecosystem service of sediment trapping.

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

PubMed

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

2006-01-01

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

Microbial community structure and function in sediments from e-waste contaminated rivers at Guiyu area of China.

PubMed

Liu, Jun; Chen, Xi; Shu, Hao-Yue; Lin, Xue-Rui; Zhou, Qi-Xing; Bramryd, Torleif; Shu, Wen-Sheng; Huang, Li-Nan

2018-04-01

The release of toxic organic pollutants and heavy metals by primitive electronic waste (e-waste) processing to waterways has raised significant concerns, but little is known about their potential ecological effects on aquatic biota especially microorganisms. We characterized the microbial community composition and diversity in sediments sampled along two rivers consistently polluted by e-waste, and explored how community functions may respond to the complex combined pollution. High-throughput 16S rRNA gene sequencing showed that Proteobacteria (particularly Deltaproteobacteria) dominated the sediment microbial assemblages followed by Bacteroidetes, Acidobacteria, Chloroflexi and Firmicutes. PICRUSt metagenome inference provided an initial insight into the metabolic potentials of these e-waste affected communities, speculating that organic pollutants degradation in the sediment might be mainly performed by some of the dominant genera (such as Sulfuricurvum, Thiobacillus and Burkholderia) detected in situ. Statistical analyses revealed that toxic organic compounds contributed more to the observed variations in sediment microbial community structure and predicted functions (24.68% and 8.89%, respectively) than heavy metals (12.18% and 4.68%), and Benzo(a)pyrene, bioavailable lead and electrical conductivity were the key contributors. These results have shed light on the microbial assemblages in e-waste contaminated river sediments, indicating a potential influence of e-waste pollution on the microbial community structure and function in aquatic ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

Warm-water reaches of the upper Colorado River have historically provided important habitat for four endangered fishes. Over time these habitats have been altered or lost due to reductions in peak flows and sediment loads caused by reservoir operations. In an effort to reverse these trends, controlled reservoir releases are now used to enhance sediment transport and restore channel complexity. In this presentation, we discuss the development of a sediment routing model designed to assess how changes in water and sediment supply can affect the mass balance of sediment. The model is formulated for ten reaches of the Colorado River spanning 250 km where values of bankfull discharge, width, and reach-average slope have been measured. Bed surface grain size distributions (GSDs) have also been measured throughout the study area; these distributions are used as a test of the model, not as input, except as an upstream boundary condition. In modeling fluxes and GSDs, we assume that the bed load transport capacity is determined by local hydraulic conditions and bed surface grain sizes. Estimates of the bankfull bed load transport capacity in each reach are computed for 14 size fractions of the surface bed material, and the fractional transport rates are summed to get the total transport capacity. In the adjacent reach, fluxes of each size fraction from upstream are used to determine the mean grain size, and the fractional transport capacity of that reach. Calculations proceed downstream and illustrate how linked changes in discharge, shear stress and mean grain size affect (1) the total bed load transport capacity, and (2) the size distribution of the bed surface sediment. The results show that model-derived GSDs match measured GSDs very closely, except for two reaches in the lower part of the study area where slope is affected by uplift associated with salt diapirs; here the model significantly overestimates the transport capacity in relation to the supply. Except for these two reaches, the modeled bed load fluxes seem reasonable (0.5-1.0 kg/m/s at bankfull flow), and exhibit downstream trends that are consistent with trends reported in previous studies. Finally, model simulations show that if reservoir releases fall short of target flows (e.g. bankfull) this can have a disproportionately negative effect on the mass balance of sediment.

Deposition, Alteration, and Resuspension of Colorado River Delta Sediments, Lake Powell, Utah

NASA Astrophysics Data System (ADS)

Kramer, N. M.; Parnell, R.

2002-12-01

Current drought conditions in the southwest United States have resulted in lowering water levels in Lake Powell, Utah. Delta sediments forming at the Colorado River inflow for the past 39 years are becoming exposed and reworked as lake levels continue to fall to over 22 meters below full pool level. Fine sediments act as a sink for pollutants by adsorbing contaminants to their surfaces. Reworking these sediments may pose a risk to water quality in the lake. We examine whether burial and time have sufficiently altered fine sediments in the delta and affected materials adsorbed on their surfaces. Fifteen lake cores and six sediment traps were collected from the sediment delta forming at the Colorado River inflow in Lake Powell. This research characterizes fine sediment mineralogy, the composition of exchangeable materials, and organic matter content within delta sediments to determine the type and amount of alteration of these sediments with cycles of burial and resuspension. We hypothesize that as sediments are reworked, organic carbon is degraded and organic nitrogen is released forming ammonium in these reducing conditions. Sediment trap samples will be used to test this hypothesis. Trap samples will be compared to subsamples from sediment cores to determine the amount of alteration of fine sediments. All samples are analyzed for organic carbon, organic nitrogen, ammonium, cation exchange capacity, exchangeable cation composition, and clay mineralogy. Organic carbon and nitrogen are analyzed using a Leco CN analyzer. Ammonium is analyzed using a Lachet ion chromatograph. Clay mineralogy is characterized using a Siemens D500 powder X-ray diffractometer. Cation exchange capacity and exchangeable cations are measured using standard soil chemical techniques. Clay mineral analyses indicate significant spatial and temporal differences in fine sediment entering the Lake Powell delta which complicates the use of a simple deposition/alteration/resuspension model using a single starting material.

Sources of suspended sediment in the Lower Roanoke River, NC

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

The influence of sediment transport rate on the development of structure in gravel bed rivers

NASA Astrophysics Data System (ADS)

Ockelford, Annie; Rice, Steve; Powell, Mark; Reid, Ian; Nguyen, Thao; Tate, Nick; Wood, Jo

2013-04-01

Although adjustments of surface grain size are known to be strongly influenced by sediment transport rate little work has systematically explored how different transport rates can affect the development of surface structure in gravel bed rivers. Specifically, it has been well established that the transport of mixed sized sediments leads to the development of a coarser surface or armour layer which occurs over larger areas of the gravel bed. Armour layer development is known to moderate overall sediment transport rate as well as being extremely sensitive to changes in applied shear stress. However, during this armouring process a bed is created where, smaller gain scale changes, to the bed surface are also apparent such as the development of pebble clusters and imbricate structures. Although these smaller scale changes affect the overall surface grain size distribution very little their presence has the ability to significantly increase the surface stability and hence alter overall sediment transport rates. Consequently, the interplay between the moderation of transport rate as a function of surface coarsening at a larger scale and moderation of transport rate as a function of the development of structure on the bed surface at the smaller scale is complicated and warrants further investigation. During experiments a unimodal grain size distribution (σg = 1.30, D50 = 8.8mm) was exposed to 3 different levels of constant discharge that produced sediment transport conditions ranging from marginal transport to conditions approaching full mobility of all size fractions. Sediment was re-circulated during the experiments surface grain size distribution bed load and fractional transport rates were measured at a high temporal resolution such that the time evolution of the beds could be fully described. Discussion concentrates on analysing the effects of the evolving bed condition sediment transport rate (capacity) and transported grain size (competence). The outcome of this research is pertinent to developing new methods of linking the development of bed surface organisation with near bed flow characteristics and bed load transport in gravel bed rivers. Keywords: Graded, Sediment, Structure

Sediment conditions in the San Antonio River Basin downstream from San Antonio, Texas, 2000-13

USGS Publications Warehouse

Ockerman, Darwin J.; Banta, J. Ryan; Crow, Cassi L.; Opsahl, Stephen P.

2015-01-01

Sediment plays an important role in the ecological health of rivers and estuaries and consequently is an important issue for water-resource managers. To better understand sediment characteristics in the San Antonio River Basin, the U.S. Geological Survey, in cooperation with the San Antonio River Authority, completed a two-part study in the San Antonio River Basin downstream from San Antonio, Texas, to (1) collect and analyze sediment data to characterize sediment conditions and (2) develop and calibrate a watershed model to simulate hydrologic conditions and suspended-sediment loads during 2000–12.

Role of hydrological events in sediment and sediment-associated heavy metals transport within a continental transboundary river system - Tuul River case study (Mongolia)

NASA Astrophysics Data System (ADS)

Pietroń, Jan; Jarsjö, Jerker

2013-04-01

The concentration of heavy metals in rivers is often greater in the sediment load than in the water solution. Overall, heavy metal conveyance with sediment transport is a significant contributor to the global transport of heavy metals. Heavy metals once released to a river system may remain in the deposits of the river from short to very long times, for instance depending on to which extent erosion and deposition can influence the sediment mass stored in the river bed. In general, the mobility of contaminated sediments to downstream water recipients may to large extent be governed by natural sediment transport dynamics during hydrological events, such as flow peaks following heavy rainfalls. The Tuul River (Northern Mongolia) belongs to a Tuul River-Orkhon River-Selenga River- transboundary river system that discharges into Lake Baikal. The river system is largely characterized by its natural hydrological regime with numerous rapid peak flow events of the spring-summer periods. However, recent studies indicate contamination of fine sediment with heavy metals coming from placer gold mining area (Zaamar Goldfield) located along the downstream Tuul River. In this work, the general idea is to create a one-dimensional sediment transport model of the downstream Tuul River, and use field-data supported modeling to investigate natural erosion-deposition rates and the role of peak flows in natural sediment transport at 14 km reach just downstream the gold mining area. The model results show that the sediment load of the finest investigated grain size has a great potential to be eroded from the bed of the studied reach, especially during the main peak flow events. However, the same events are associated with a significant deposition of the finest material. The model results also show different hysteresis behavior of the sediment load rating curves (clockwise and counter-clockwise) during the main peak flow events. These are interpreted as effects of changing in-channel sediment supplies due to sorting method applied in the model. More generally, the modelling may increase our knowledge about the sediment transport patterns of the reach downstream the mining area. This part of the river may be considered as a temporal sink of heavy metals which may accumulate and store sediments. The deposition in such sinks can considerably support attenuation of contaminated sediment loads. On the other hand, sediments that are accumulated in sinks can increase the concentration of contaminated sediment loads during peak flow events. Information about the rates of eroded and accumulated contaminated material in such sinks is important for future water protection planning, especially under changing climate conditions. This work may also provide scientific input to discussions on both adverse environmental consequences of placer mining, and suitable designs of sediment control measures in the Zaamar Goldfield and other continental river systems.

Occurrence of organotin compounds in river sediments under the dynamic water level conditions in the Three Gorges Reservoir Area, China.

PubMed

Gao, Jun-Min; Zhang, Ke; Chen, You-Peng; Guo, Jin-Song; Wei, Yun-Mei; Jiang, Wen-Chao; Zhou, Bin; Qiu, Hui

2015-06-01

The Three Gorges Project is the largest hydro project in the world, and the water level of the Three Gorges Reservoir (TGR) is dynamic and adjustable with the aim of flood control and electrical power generation. It is necessary to investigate the pollutants and their underlying contamination processes under dynamic water levels to determine their environmental behaviors in the Three Gorges Reservoir Area (TGRA). Here, we report the assessment of organotin compounds (OTs) pollution in the river sediments of the TGRA. Surface sediment samples were collected in the TGRA at low and high water levels. Tributyltin (TBT), triphenyltin (TPhT), and their degradation products in sediments were quantified by gas chromatography-mass spectrometry. Butyltins (BTs) and phenyltins (PhTs) were detected in sediments, and BTs predominated over PhTs in the whole study area under dynamic water level conditions. The concentrations of OTs in sediments varied markedly among locations, and significant concentrations were found in river areas with high levels of boat traffic and wastewater discharge. Sediments at all stations except Cuntan were lightly contaminated with TBT, and total organic carbon (TOC) was a significant factor affecting the fate of TBT in the TGRA. The butyltin and phenyltin degradation indices showed no recent inputs of TBT or TPhT into this region, with the exception of fresh TPhT input at Xiakou Town. Shipping activity, wastewater discharge, and agriculture are the most likely sources of OTs in the TGRA.

Sources of land-derived runoff to a coral reef-fringed embayment identified using geochemical tracers in nearshore sediment traps

USGS Publications Warehouse

Takesue, Renee K.; Bothner, Michael H.; Reynolds, Richard L.

2009-01-01

Geochemical tracers, including Ba, Co, Th, 7Be, 137Cs and 210Pb, and magnetic properties were used to characterize terrestrial runoff collected in nearshore time-series sediment traps in Hanalei Bay, Kauai, during flood and dry conditions in summer 2006, and to fingerprint possible runoff sources in the lower watershed. In combination, the tracers indicate that runoff during a flood in August could have come from cultivated taro fields bordering the lower reach of the river. Land-based runoff associated with summer floods may have a greater impact on coral reef communities in Hanalei Bay than in winter because sediment persists for several months. During dry periods, sediment carried by the Hanalei River appears to have been mobilized primarily by undercutting of low 7Be, low 137Cs riverbanks composed of soil weathered from tholeiitic basalt with low Ba and Co concentrations. Following a moderate rainfall event in September, high 7Be sediment carried by the Hanalei River was probably mobilized by overland flow in the upper watershed. Ba-desorption in low-salinity coastal water limited its use to a qualitative runoff tracer in nearshore sediment. 210Pb had limited usefulness as a terrestrial tracer in the nearshore due to a large dissolved oceanic source and scavenging onto resuspended bottom sediment. 210Pb-scavenging does, however, illustrate the role resuspension could play in the accumulation of particle-reactive contaminants in nearshore sediment. Co and 137Cs were not affected by desorption or geochemical scavenging and showed the greatest potential as quantitative sediment provenance indicators in material collected in nearshore sediment traps.

Ephemeral seafloor sedimentation during dam removal: Elwha River, Washington

NASA Astrophysics Data System (ADS)

Foley, Melissa M.; Warrick, Jonathan A.

2017-11-01

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

Contribution of the upper river, the estuarine region, and the adjacent sea to the heavy metal pollution in the Yangtze Estuary.

PubMed

Yin, Su; Wu, Yuehan; Xu, Wei; Li, Yangyang; Shen, Zhenyao; Feng, Chenghong

2016-07-01

To determine whether the discharge control of heavy metals in the Yangtze River basin can significantly change the pollution level in the estuary, this study analyzed the sources (upper river, the estuarine region, and the adjacent sea) of ten heavy metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, and Zn) in dissolved and particulate phases in the surface water of the estuary during wet, normal, and dry seasons. Metal sources inferred from section fluxes agree with those in statistical analysis methods. Heavy metal pollution in the surface water of Yangtze Estuary primarily depends on the sediment suspension and the wastewater discharge from estuary cities. Upper river only constitutes the main source of dissolved heavy metals during the wet season, while the estuarine region and the adjacent sea (especially the former) dominate the dissolved metal pollution in the normal and dry seasons. Particulate metals are mainly derived from sediment suspension in the estuary and the adjacent sea, and the contribution of the upper river can be neglected. Compared with the hydrologic seasons, flood-ebb tides exert a more obvious effect on the water flow directions in the estuary. Sediment suspension, not the upper river, significantly affects the suspended particulate matter concentration in the estuary. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Spatial distribution and ecological risk assessment of heavy metals in the estuaries surface sediments from the Haihe River Basin].

PubMed

Lü, Shu-Cong; Zhang, Hong; Shan, Bao-Qing; Li, Li-Qing

2013-11-01

It is well known that the rivers in the Haihe River Basin have been seriously polluted. However, what is the present condition of the estuary pollution and how the polluted inland rivers affect the estuary areas are not clear. 10 main estuaries of the Haihe River Basin were selected to measure the contents of typical heavy metals (Pb, Cu, Zn, Cd, Cr and Ni) in the surface sediments and to analyze the spatial distribution of these heavy metals. The potential ecological risk index was used to assess the ecological risk of the six heavy metals in the estuaries. The results showed that the contents of Pb, Cu, Zn, Cd, Cr and Ni in the surface sediments of the 10 estuaries were all higher than their background values in the main local soil types and the contents of Cu, Ni and Pb were 2.3-2.6 times as high as their background values, which indicated that the estuaries were contaminated by the six heavy metals. The results also indicated that the contents of the six heavy metals in surface sediment varied from one estuary to another. The four heavy metals of Cr, Cu, Ni and Zn had bigger spatial differences than Pb and Cd in the contents in sediment from different estuaries. The contents of Cr, Cu, Ni and Zn in sediment were higher in the estuaries of the Yongdingxin River, Ziyaxin River and Beipai River than those in the other estuaries, and there were significant correlations between each other (R(Cu-Zn) = 0.891, R(Cu-Cr) = 0.927, R(Cu-Ni) = 0.964, R(Zn-Cr) = 0.842, R(Zn-Ni) = 0.939, and R(Cr-Ni) = 0.879, P < 0.01), which indicated that they possibly came from the same sources. Moreover, the contents of Cr, Cu, Ni and Zn in sediment also had significant correlations with the populations of sub-river basins with correlation coefficients of 0.855, 0.806, 0.867 and 0.855 (P < 0.01), respectively. The contents of Cd and Pb had smaller spatial differences in sediment from different estuaries than the other heavy metals, with the values ranged 23.3-95.8 mg x kg(-1) and 0.051-0.200 mg x kg(-1). Contents of the two heavy metals had no significant correlation with the other heavy metals or with the populations of sub-river basins, indicating that Cd and Pb had little connection with the in-land polluted sources. The results of ecological risk assessment showed that estuaries of the Haihe River Basin had the potential ecological risk at lower levels (RI were 33.7-116) and the most important contaminating element was Cd with a middle-level potential ecological risk (Er(i) were 18.0-48.9).

Physical Drivers Vs. Effects of the Wolf-Elk Trophic Cascade on Fluvial Channel Planform, Olympic National Park, Washington

NASA Astrophysics Data System (ADS)

East, A. E.; Jenkins, K. J.; Happe, P. J.; Bountry, J.; Beechie, T. J.; Mastin, M. C.; Sankey, J. B.; Randle, T. J.

2016-12-01

Identifying the relative contributions of physical and ecological processes to channel evolution remains a substantial challenge in fluvial geomorphology. We use a 74-year aerial photographic record of the Hoh, Queets, Quinault, and Elwha Rivers, Olympic National Park, Washington, U.S.A., to investigate whether physical or trophic-cascade-driven ecological factors—excessive elk impacts after wolves were extirpated a century ago—are the dominant controls on channel planform of these gravel-bed rivers. We find that channel width and braiding show strong relationships with recent flood history; all four rivers have widened significantly in recent decades, consistent with increased flood activity since the 1970s. Channel planform also reflects sediment-supply changes, shown, for example, by the response of the Elwha River to a landslide. We surmise that the Hoh River, which shows a multi-decadal trend toward greater braiding, is adjusting to increased sediment supply associated with rapid glacial retreat. These rivers demonstrate rapid transmission of climatic signals through relatively short sediment-routing systems that lack substantial buffering by sediment storage. We infer no correspondence between channel evolution and elk abundance, suggesting that in this system effects of the wolf-driven trophic cascade are subsidiary to physical controls on channel morphology. Our examinations of stage-discharge history, historical maps, photographs, and descriptions, and empirical geomorphic thresholds do not support a previous conceptual model that these rivers underwent a fundamental geomorphic transition (widening, and a shift from single-thread to braided) resulting from large elk populations in the early 20th century. These findings differ from previous interpretations of Olympic National Park river dynamics, and also contrast with previous findings in Yellowstone National Park, where legacy effects of abundant elk nearly a century ago apparently still affect channel and floodplain morphology and connectivity. Different responses of Olympic and Yellowstone river morphology to trophic-cascade factors are likely due to hydrologic regime and large-wood availability.

Geomorphic response of the Sandy River, Oregon, to removal of Marmot Dam

USGS Publications Warehouse

Major, Jon J.; O'Connor, Jim E.; Podolak, Charles J.; Keith, Mackenzie K.; Grant, Gordon E.; Spicer, Kurt R.; Pittman, Smokey; Bragg, Heather M.; Wallick, J. Rose; Tanner, Dwight Q.; Rhode, Abagail; Wilcock, Peter R.

2012-01-01

The October 2007 breaching of a temporary cofferdam constructed during removal of the 15-meter (m)-tall Marmot Dam on the Sandy River, Oregon, triggered a rapid sequence of fluvial responses as ~730,000 cubic meters (m3) of sand and gravel filling the former reservoir became available to a high-gradient river. Using direct measurements of sediment transport, photogrammetry, airborne light detection and ranging (lidar) surveys, and, between transport events, repeat ground surveys of the reservoir reach and channel downstream, we monitored the erosion, transport, and deposition of this sediment in the hours, days, and months following breaching of the cofferdam. Rapid erosion of reservoir sediment led to exceptional suspended-sediment and bedload-sediment transport rates near the dam site, as well as to elevated transport rates at downstream measurement sites in the weeks and months after breaching. Measurements of sediment transport 0.4 kilometers (km) downstream of the dam site during and following breaching show a spike in the transport of fine suspended sediment within minutes after breaching, followed by high rates of suspended-load and bedload transport of sand. Significant transport of gravel bedload past the measurement site did not begin until 18 to 20 hours after breaching. For at least 7 months after breaching, bedload transport rates just below the dam site during high flows remained as much as 10 times above rates measured upstream of the dam site and farther downstream. The elevated sediment load was derived from eroded reservoir sediment, which began eroding when a meters-tall knickpoint migrated about 200 m upstream in the first hour after breaching. Rapid knickpoint migration triggered vertical incision and bank collapse in unconsolidated sand and gravel, leading to rapid channel widening. Over the following days and months, the knickpoint migrated upstream more slowly, simultaneously decreasing in height and becoming less distinct. Within 7 months, the knickpoint had migrated 2 km upstream from the dam site and became a riffle-like feature approximately 1 m high and a few tens of meters long. Knickpoint migration, vertical incision, and lateral erosion evacuated about 15 percent of the initial reservoir volume (125,000 m3) within 60 hours following breaching, and by the end of the high flows in May 2008, about 50 percent of the volume had been evacuated. Large stormflows in November 2008 and January 2009 eroded another 6 percent of the original volume of impounded sediment. Little additional sediment eroded during the remainder of the second year following breaching. The rapid erosion of sediment by the modest flow that accompanied dam breaching was driven mainly by the steep hydraulic gradient associated with the abrupt change of base level and knickpoint formation and was aided by the unconsolidated and cohesionless character of the reservoir sediment. In the ensuing months, transport competence diminished as channel geometry evolved and the river gradient through the reservoir reach diminished. Changes in profile gradient in conjunction with channel coarsening and widening led to a rapid slowing of the rate of reservoir erosion. Sediment transport and deposition were strongly controlled by channel-gradient discontinuities and valley morphology downstream of the dam site. Those influences led to a strong divergence of sand and gravel transport and to deposition of a sediment wedge, as much as 4 m thick, that tapered to the preremoval channel bed 1.3 km downstream of the dam site. After 2 years, that deposit contained about 25 percent of the total volume of sediment eroded from the reservoir. The balance was distributed among pools within the Sandy River gorge, a narrow bedrock canyon extending 2 to 9 km downstream of the dam site, and along the channel farther downstream. A two-fraction sediment budget for the first year following breaching indicates that most of the gravel eroded from the reservoir reach was deposited within the sediment wedge and within the gorge, whereas eroded sand largely passed through the gorge and was broadly dispersed farther downstream. The sequence of transporting flows affected the specific trajectory of reservoir erosion and downstream sediment transport during the 2 years following breaching. However, because the overall erosion was largely a consequence of knickpoint retreat and channel widening, which in the 2 years after removal had affected most of the reservoir reach, it is unlikely that the specific sequence of flows significantly affected the overall outcome. Because the knickpoint had largely passed through the reservoir within 2 years, and the remaining reservoir sediment is mostly isolated high above armored or bedrock banks, it is unlikely that substantial additional sediment from the reservoir site will enter the system unless very large flows occur. Continued channel evolution downstream of the dam site is probable as deposits formed in the first 2 years are episodically mobilized. Below the Sandy River gorge, detection of effects related to release of reservoir sediment is challenging, especially in areas of sand deposition, because of the high background supply of sand in the river and substantial channel dynamism.

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

USGS Publications Warehouse

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

2012-01-01

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

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

USGS Publications Warehouse

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

2017-11-01

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

Reservoir-flooded river mouth areas as sediment traps revealing erosion from peat mining areas - Jukajoki case study in eastern Finland

NASA Astrophysics Data System (ADS)

Tahvanainen, Teemu; Meriläinen, Henna-Kaisa; Haraguchi, Akira; Simola, Heikki

2016-04-01

Many types of soil-disturbing land use have caused excess sedimentation in Finnish lakes. Identification and quantification of catchment sources of sediment material is crucial in cases where demands for remediation measures are considered. We studied recent (50 yr) sediments of four small rivers, all draining to a reservoir impounded in 1971. Catchments of two of the rivers had had peat mining activities from early 1980s until recently, exposing large areas of peat surfaces to erosion. The water level of the reservoir had risen to the river mouth areas of all rivers, while in each case, the river mouth areas still form riverine narrows separable from the main reservoir, hence collecting sedimentation from their own catchments. The original soils under the reservoir water level could readily be observed in core samples, providing a dated horizon under recent sediments. In addition, we used 137Cs-stratigraphies for dating of samples from original river bed locations. As expected, recent sediments of rivers with peat mining influence differed from others e.g. by high organic content and C:N ratios. Stable isotopes 13C and 15N both correlated with C:N (r = 0.799 and r = -0.717, respectively) and they also differentiated the peat-mining influenced samples from other river sediments. Principal components of the physical-chemical variables revealed clearer distinction than any variables separately. Light-microscopy revealed abundance of leafs of Sphagnum mosses in peat-mining influenced river sediments that were nearly absent from other rivers. Spores of Sphagnum were, however, abundant in all river sediments indicating their predominantly airborne origin. We find that combination of several physical-chemical characters rather than any single variable and microscopy of plant remains can result in reliable recognition of peatland-origin of sediment material when non-impacted sites are available for comparison. Dating of disturbed recent sediments is challenging. River-mouth areas with reservoir history can be particularly useful as the terrestrial soil strata provides a dated horizon under recent sediments.

Fluvial bar dynamics in large meandering rivers with different sediment supply in the Amazon River basin

NASA Astrophysics Data System (ADS)

Monegaglia, Federico; Zolezzi, Guido; Tubino, Marco; Henshaw, Alex

2017-04-01

Sediments in the large meandering rivers of the Amazon basin are known to be supplied by sources providing highly different magnitudes of sediment input and storage, ranging from the sediment-rich Andean region to the sediment-poor Central Trough. Recent observations have highlighted how such differences in sediment supply have an important, net effect on the rates of planform activity of meandering rivers in the basin, in terms of meander migration and frequency of cutoffs. In this work we quantify and discuss the effect of sediment supply on the organization of macroscale sediment bedforms on several large meandering rivers in the Amazon basin, and we link our findings with those regarding the rates of planform activity. Our analysis is conducted through the newly developed software PyRIS, which enables us to perform extensive multitemporal analysis of river morphodynamics from multispectral remotely sensed Landsat imagery in a fully automated fashion. We show that large rivers with low sediment supply tend to develop alternate bars that consistently migrate through long reaches, characterized at the same time by limited planform development. On the contrary, high sediment supply is associated with the development of point bars that are well-attached to the evolving meander bends and that follow temporal oscillations around the bend apexes, which in turn show rapid evlution towards complex meander shapes. Finally, rivers with intermediate rates of sediment supply develop rather steady point bars associated with slowly migrating, regular meanders. We finally discuss the results of the image analysis in the light of the properties of river planform metrics (like channel curvature and width) for the examined classes of river reaches with different sediment supply rates.

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

NASA Astrophysics Data System (ADS)

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

2018-05-01

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

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

USGS Publications Warehouse

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

2006-01-01

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

[Concentrations and Distribution of Metals in the Core Sediments from Estuary and City Section of Liaohe River].

PubMed

Wang, Wei-jie; Zhou, Jun-li; Pei, Shu-wei; Liu, Zheng-tao

2016-01-15

The particle size, total organic carbon (TOC), total nitrogen (TN), C/N ratio and metal concentrations as well as activities of 210Pb were determined in Liaohe River estuary area (LN-2) and Shenyang area (LN-5), and the organic matter resources were discussed in two core sediments. Also the index of geoaccumulation (Igeo) and enrichment factors (EFs) methods were applied to evaluate the state of heavy metal contamination in the studied sties. The study showed that both sediment cores LN-2 and LN-5 were dominated by silts, and the vertical variations of grain-size composition and organic matter were well distributed in LN- 2 while fluctuated in LN-5. According to the organic matter source analysis through C/N ratio, C/N ratio varied in the scale of 5. 24-7.93 in LN-2 which was dominated by river source, and 9.94-14.21 in LN-5 which was dominated by terrestrial input. Al, Ca, Fe, Mn, Ni, Cu, Zn, Cd, Pb and Cr in two sediment cores had different vertical changing rules, Ni and Zn in LN-2 as well as Pb and Zn in LN-5 were affected by both natural and human factors, other elements had similar distributions to those of organic matters, which showed that these elements were mainly affected by the natural activities. Based on Igeo and EFs, both sediment cores were more severely polluted with Ni, Zn and Pb than other metals. The effects of human activities on the environment were also discussed in this study, combined with the economical development of Liaoning Province and the studied sites in the past 20 years.

The Columbia River--on the Leading Edge

NASA Astrophysics Data System (ADS)

O'Connor, J. E.

2005-05-01

On the leading edge of the North American plate, the Columbia River is the largest of the world's 40 or so rivers with drainage areas greater than 500,000 square kilometers to drain toward a convergent plate boundary. This unique setting results in a unique continental river basin; marked by episodic and cataclysmic geologic disturbance, but also famously fecund with perhaps 10 to 16 million salmon historically spawning in its waters each year. Now transformed by dams, transportation infrastructure, dikes and diversions, the Columbia River presents an expensive conundrum for management of its many values. Inclusion of river ecology and geomorphology in discussions of river management is generally limited to observations of the last 200 years-a time period of little natural disturbance and low sediment transport. However, consideration of longer timescales provides additional perspective of historical ecologic and geomorphic conditions. Only 230 km from its mouth, the Columbia River bisects the volcanic arc of the Cascade Range, forming the Columbia River Gorge. Cenozoic lava flows have blocked the river, forcing diversions and new canyon cutting. Holocene eruptions of Mount Mazama (Crater Lake), Mount Hood, Mount St. Helens, and Mount Rainier have shed immense quantities of sediment into the lower Columbia River, forming a large percentage of the Holocene sediment transported through the lower river. Quaternary landslides, perhaps triggered by great earthquakes, have descended from the 1000-m-high gorge walls, also blocking and diverting the river, one as recently as 550 years ago. These geologic disturbances, mostly outside the realm of historical observation and operating at timescales of 100s to 1000s of years in the gorge and elsewhere, have clearly affected basin geomorphology, riverine ecology, and past and present cultural utilization of river resources. The historic productivity of the river, however, hints at extraordinary resilience (and perhaps dependence) of the Columbia River system to such disturbances, many of which are similar to engineered disturbances of the last 200 years.

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

PubMed

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

2009-08-13

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

Suspended Sediment Dynamics in the Macrotidal Seine Estuary (France): 2. Numerical Modeling of Sediment Fluxes and Budgets Under Typical Hydrological and Meteorological Conditions

NASA Astrophysics Data System (ADS)

Schulz, E.; Grasso, F.; Le Hir, P.; Verney, R.; Thouvenin, B.

2018-01-01

Understanding the sediment dynamics in an estuary is important for its morphodynamic and ecological assessment as well as, in case of an anthropogenically controlled system, for its maintenance. However, the quantification of sediment fluxes and budgets is extremely difficult from in-situ data and requires thoroughly validated numerical models. In the study presented here, sediment fluxes and budgets in the lower Seine Estuary were quantified and investigated from seasonal to annual time scales with respect to realistic hydro- and meteorological conditions. A realistic three-dimensional process-based hydro- and sediment-dynamic model was used to quantify mud and sand fluxes through characteristic estuarine cross-sections. In addition to a reference experiment with typical forcing, three experiments were carried out and analyzed, each differing from the reference experiment in either river discharge or wind and waves so that the effects of these forcings could be separated. Hydro- and meteorological conditions affect the sediment fluxes and budgets in different ways and at different locations. Single storm events induce strong erosion in the lower estuary and can have a significant effect on the sediment fluxes offshore of the Seine Estuary mouth, with the flux direction depending on the wind direction. Spring tides cause significant up-estuary fluxes at the mouth. A high river discharge drives barotropic down-estuary fluxes at the upper cross-sections, but baroclinic up-estuary fluxes at the mouth and offshore so that the lower estuary gains sediment during wet years. This behavior is likely to be observed worldwide in estuaries affected by density gradients and turbidity maximum dynamics.

Inaccuracies in sediment budgets arising from estimations of tributary sediment inputs: an example from a monitoring network on the southern Colorado plateau

USGS Publications Warehouse

Griffiths, Ronald; Topping, David

2015-01-01

Sediment budgets are an important tool for understanding how riverine ecosystems respond to perturbations. Changes in the quantity and grain-size distribution of sediment within river systems affect the channel morphology and related habitat resources. It is therefore important for resource managers to know if a channel reach is in a state of sediment accumulation, deficit or stasis. Many studies have estimated sediment loads from ungaged tributaries using regional sediment-yield equations or other similar techniques. While these approaches may be valid in regions where rainfall and geology are uniform over large areas, use of sediment-yield equations may lead to poor estimations of sediment loads in semi-arid climates, where rainfall events, contributing geology, and vegetation have large spatial variability.

New Insights About Large-Scale Delta Morphodynamics from a Coupled Model of Fluvial-Coastal Processes

NASA Astrophysics Data System (ADS)

Murray, A. B.; Ratliff, K. M.; Hutton, E.

2017-12-01

We use a newly developed delta model to explore the combined effects of sea-level rise (SLR) and variable wave influence on delta morphology, avulsion behavior, and autogenic sediment flux variability. Using the Community Surface Dynamics Modeling System framework and tools, we couple the River Avulsion and Floodplain Evolution Model (RAFEM) to the Coastline Evolution Model (CEM). RAFEM models the fluvial processes, including river profile evolution, floodplain deposition, and avulsions. CEM uses gradients in alongshore sediment transport to distribute the fluvial sediment along the coastline. A suite of recent experiments using the coupled model and the Dakota software toolkit lead to several new insights: 1) A preferential avulsion location (which scales with the backwater length) can arise for geometric reasons that are independent of the recently suggested importance of alternation between flood and inter-flood periods. 2) The angular distribution of waves, as well as the wave height, affect the avulsion timescale. Previous work suggested that the time between avulsions will increase with greater wave influence, and we find that this is true for an angular mix of waves that tends to smooth a fairly straight coastline (coastline diffusion), where river mouth progradation is slowed and avulsions are delayed. However, if the angular distribution of waves leads to locally smooth shorelines but large amplitude coastline features (anti-diffusive coastline evolution), then avulsion timescales are barely affected, even when wave influence is high. 3) Increasing SLR rates are expected to cause more frequent avulsions, and it does in laboratory deltas. Unexpectedly, we find that this is not the case for the river-dominated deltas in our coupled model, in which SLR-related transgression effectively decreases progradation, offsetting base-level-rise effects. This finding raises potentially important questions about the geometric differences between prototypical and laboratory deltas that have not previously been addressed. 4) The magnitude and timescale of autogenic variability in the sediment flux at the river mouth depends on the SLR rate (for some wave climates), wave characteristics, and the how high the river channel must be super-elevated relative to the floodplain in order to trigger an avulsion.

On the Holocene evolution of the Ayeyawady megadelta

NASA Astrophysics Data System (ADS)

Giosan, Liviu; Naing, Thet; Tun, Myo Min; Clift, Peter D.; Filip, Florin; Constantinescu, Stefan; Khonde, Nitesh; Blusztajn, Jerzy; Buylaert, Jan-Pieter; Stevens, Thomas; Thwin, Swe

2018-06-01

The Ayeyawady delta is the last Asian megadelta whose evolution has remained essentially unexplored so far. Unlike most other deltas across the world, the Ayeyawady has not yet been affected by dam construction, providing a unique view on largely natural deltaic processes benefiting from abundant sediment loads affected by tectonics and monsoon hydroclimate. To alleviate the information gap and provide a baseline for future work, here we provide a first model for the Holocene development of this megadelta based on drill core sediments collected in 2016 and 2017, dated with radiocarbon and optically stimulated luminescence, together with a reevaluation of published maps, charts and scientific literature. Altogether, these data indicate that Ayeyawady is a mud-dominated delta with tidal and wave influences. The sediment-rich Ayeyawady River built meander belt alluvial ridges with avulsive characters. A more advanced coast in the western half of the delta (i.e., the Pathein lobe) was probably favored by the more western location of the early course of the river. Radiogenic isotopic fingerprinting of the sediment suggests that the Pathein lobe coast does not receive significant sediment from neighboring rivers. However, the eastern region of the delta (i.e., Yangon lobe) is offset inland and extends east into the mudflats of the Sittaung estuary. Wave-built beach ridge construction during the late Holocene, similar to several other deltas across the Indian monsoon domain, suggests a common climatic control on monsoonal delta morphodynamics through variability in discharge, changes in wave climate or both. Correlation of the delta morphological and stratigraphic architecture information on land with the shelf bathymetry, as well as its tectonic, sedimentary and hydrodynamic characteristics, provides insight on the peculiar growth style of the Ayeyawady delta. The offset between the western Pathein lobe and the eastern deltaic coast appears to be driven by tectonic-hydrodynamic feedbacks as the extensionally lowered shelf block of the Gulf of Mottama amplifies tidal currents relative to the western part of the shelf. This situation probably activates a perennial shear front between the two regions that acts as a leaky energy fence. Just as importantly, the strong currents in the Gulf of Mottama act as an offshore-directed tidal pump that helps build the deep mid-shelf Mottama clinoform with mixed sediments from the Ayeyawady, Sittaung and Thanlwin rivers. The highly energetic tidal, wind and wave regime of the northern Andaman Sea thus exports most sediment offshore despite the large load of the Ayeyawady River.

Sediment heterogeneity and mobility in the morphodynamic modelling of gravel-bed braided rivers

NASA Astrophysics Data System (ADS)

Singh, Umesh; Crosato, Alessandra; Giri, Sanjay; Hicks, Murray

2017-06-01

The effects of sediment heterogeneity and sediment mobility on the morphology of braided rivers are still poorly studied, especially when the partial sediment mobility occurs. Nevertheless, increasing the bed sediment heterogeneity by coarse sediment supply is becoming a common practice in river restoration projects and habitat improvement all over the world. This research provides a step forward in the identification of the effects of sediment sorting on the evolution of sediment bars and braiding geometry of gravel-bed rivers. A two-dimensional morphodynamic model was used to simulate the long-term developments of a hypothetical braided system with discharge regime and morphodynamic parameters derived from the Waimakariri River, New Zealand. Several scenarios, differing in bed sediment heterogeneity and sediment mobility, were considered. The results agree with the tendencies already identified in linear analyses and experimental studies, showing that a larger sediment heterogeneity increases the braiding indes and reduces the bars length and height. The analyses allowed identifying the applicability limits of uniform sediment and variable discharge modelling approaches.

Nutrient cycling, connectivity, and free-floating plant abundance in backwater lakes of the Upper Mississippi River

USGS Publications Warehouse

Houser, Jeff N.; Giblin, Shawn M.; James, William F.; Langrehr, H.A.; Rogala, James T.; Sullivan, John F.; Gray, Brian R.

2013-01-01

River eutrophication may cause the formation of dense surface mats of free floating plants (FFP; e.g., duckweeds and filamentous algae) which may adversely affect the ecosystem. We investigated associations among hydraulic connectivity to the channel, nutrient cycling, FFP, submersed aquatic vegetation (SAV), and dissolved oxygen concentration (DO) in ten backwater lakes of the Upper Mississippi River (UMR) that varied in connectivity to the channel. Greater connectivity was associated with higher water column nitrate (NO3-N) concentration, higher rates of sediment phosphorus (P) release, and higher rates of NO3-N flux to the sediments. Rates of sediment P and N (as NH4-N) release were similar to those of eutrophic lakes. Water column nutrient concentrations were high, and FFP tissue was nutrient rich suggesting that the eutrophic condition of the UMR often facilitated abundant FFP. However, tissue nutrient concentrations, and the associations between FFP biomass and water column nutrient concentrations, suggested that nutrients constrained FFP abundance at some sites. FFP abundance was positively associated with SAV abundance and negatively associated with dissolved oxygen concentration. These results illustrate important connections among hydraulic connectivity, nutrient cycling, FFP, SAV, and DO in the backwaters of a large, floodplain river.

Coastal change from a massive sediment input: Dam removal, Elwha River, Washington, USA

USGS Publications Warehouse

Warrick, Jonathan A.; Gelfenbaum, Guy R.; Stevens, Andrew; Miller, Ian M.; Kaminsky, George M.; Foley, Melissa M.

2015-01-01

The removal of two large dams on the Elwha River, Washington, provides an ideal opportunity to study coastal morphodynamics during increased sediment supply. The dam removal project exposed ~21 million cubic meters (~30 million tonnes) of sediment in the former reservoirs, and this sediment was allowed to erode by natural river processes. Elevated rates of sand and gravel sediment transport in the river occurred during dam removal. Most of the sediment was transported to the coast, and this renewed sediment supply resulted in hundreds of meters of seaward expansion of the river delta since 2011. Our most recent survey in January 2015 revealed that a cumulative ~3.5 million m3 of sediment deposition occurred at the delta since the beginning of the dam removal project, and that aggradation had exceeded 8 m near the river mouth. Some of the newly deposited sediment has been shaped by waves and currents into a series of subaerial berms that appear to move shoreward with time.

Zambezi River Delta

NASA Image and Video Library

2013-08-29

It drains a watershed that spans eight countries and nearly 1.6 million square kilometers 600,000 square miles. The Zambezi also Zambeze is the fourth largest river in Africa, and the largest east-flowing waterway. The Operational Land Imager on the Landsat 8 satellite acquired this natural-color image of the Zambezi Delta on August 29, 2013. Sandbars and barrier spits stretch across the mouths of the delta, and suspended sediment extends tens of kilometers out into the sea. The sandy outflow turns the coastal waters to a milky blue-green compared to the deep blue of open water in the Indian Ocean. The Zambezi Delta includes 230 kilometers of coastline fronting 18,000 square kilometers (7,00 square miles) of swamps, floodplains, and even savannahs (inland). The area has long been prized by subsistence fishermen and farmers, who find fertile ground for crops like sugar and fertile waters for prawns and fish. Two species of endangered cranes and one of the largest concentration of buffalo in Africa -- among many other species of wildlife -- have found a haven in this internationally recognized wetland. However, the past six decades have brought great changes to the Zambezi Delta, which used to pour more water and sediment off of the continent. Hydropower dams upstream-most prominently, the Kariba and the Cahora Bassa-greatly reduce river flows during the wet season; they also trap sediments that would otherwise flow downstream. The result has been less water reaching the delta and the floodplains, which rely on pulses of nutrients and sediments from annual (and mostly benign) natural flooding. The change in the flow of the river affects freshwater availability and quality in the delta. Strong flows push fresh water further out into the sea and naturally keep most of a delta full of fresh (or mostly fresh) water. When that fresh flow eases, the wetlands become drier and more prone to fire. Salt water from the Indian Ocean also can penetrate further into the marsh, upsetting the ecological balance for aquatic plant and animal species. Researchers have found that the freshwater table in the delta has dropped as much as five meters in the 50 years since dams were placed on the river. Less river flow also affects the shape and extent of the delta. Today there is less sediment replenishing the marshes and beaches as they are scoured by ocean waves and tides. "What strikes me in this image is the suspended sediment offshore," said Liviu Giosan, a delta geologist at the Woods Hole Oceanographic Institution. "Sediment appears to be transferred from the delta offshore in plumes that not only originate in active river mouths but also from deactivated former mouths, now tidal channels. This shows the power of tidal scouring contributing to the slow but relentless erosion of the delta." http://photojournal.jpl.nasa.gov/catalog/PIA18155

Clay mineralogy and source-to-sink transport processes of Changjiang River sediments in the estuarine and inner shelf areas of the East China Sea

NASA Astrophysics Data System (ADS)

Zhao, Yifei; Zou, Xinqing; Gao, Jianhua; Wang, Chenglong; Li, Yali; Yao, Yulong; Zhao, Wancang; Xu, Min

2018-02-01

We examined the source-to-sink sediment transport processes from the Changjiang River to the estuarine coastal shelf area by analyzing the clay mineral assemblages in suspended sediment samples from the Changjiang River catchment and surface samples from the estuarine coastal shelf area following the impoundment of the Three Gorges Dam (TGD) in 2003. The results indicate that the clay mineral compositions throughout the study area are dominated by illite, with less abundant kaolinite and chlorite and scarce smectite. The clay minerals display distinct differences in the tributaries and exhibit obvious changes in the trunk stream compared with the periods before 2003, and the source of sediment has largely shifted to the mid- to lower reaches of the river after 2003. Spatially, the clay mineral assemblages in the estuarine area define two compositionally distinct provinces. Province I covers the mud area of the Changjiang River estuary and the Zhe-Min coastal region, where sediment is primarily supplied by the Changjiang River. Province II includes part of the Changjiang River estuary and the southeastern portion of the study area, where the sediment is composed of terrestrial material from the Changjiang River and re-suspended material from the Huanghe River carried by the Jiangsu coastal current. Moreover, the other smaller rivers in China (including the Oujiang and Minjiang rivers of mainland China and the rivers of West Taiwan) also contribut sediments to the estuarine and inner shelf areas. In general, the clay mineral assemblages in the Changjiang River estuarine area are have mainly been controlled by sediment supplied from upstream of the Changjiang River tributaries. However, since the completion of the TGD in 2003, the mid- to downstream tributaries have become the main source of sediments from the Changjiang catchment into the East China Sea. These analyses further demonstrate that the coastal currents and the decrease in the sediment load of the river have the greatest impacts on the distribution and transport of clay minerals assemblages in the sediments.

Distribution and Sources of Petroleum Hydrocarbons in Recent Sediments of the Imo River, SE Nigeria.

PubMed

Oyo-Ita, Inyang O; Oyo-Ita, Orok E; Dosunmu, Miranda I; Domínguez, Carmen; Bayona, Josep M; Albaigés, Joan

2016-02-01

The distribution of aliphatic and aromatic hydrocarbons in surface sediments of the lower course of the Imo River (Nigeria) was investigated to determine the sources and fate of these compounds. The aliphatic fraction is characterized by a widespread contribution of highly weathered/biodegraded hydrocarbon residues (reflected in the absence of prominent n-alkane peaks coupled with the presence of 17α(H),21β(H)-25-norhopane, an indicator of heavy hydrocarbon biodegradation) of Nigerian crude oils (confirmed by the occurrence of 18α(H)-oleanane, a compound characteristic of oils of deltaic origin). The concentrations of polycyclic aromatic hydrocarbons (PAHs) ranging from 48 to 117 ng/g dry weight (dw; ∑13PAHs) indicate a moderate pollution, possibly lowered by the sandy lithology and low organic carbon (OC) content of the sediments. Concentrations slightly decrease towards the estuary of the river, probably due to the fact that these stations are affected by tidal flushing of pollutants adsorbed on sediment particles and carried away by occasional storm to the Atlantic Ocean. A number of PAH ratios, including parent/alkylated and isomeric compounds, indicates a predominance of petrogenic sources, with a low contribution of pyrolytic inputs, particularly of fossil fuel combustion. On the basis of OC/ON (>10) and Per/ΣPAHpenta- (>10) values, a diagenetic terrigenous OC was proposed as a source of perylene to the river.

Stepwise morphological evolution of the active Yellow River (Huanghe) delta lobe (1976-2013): Dominant roles of riverine discharge and sediment grain size

NASA Astrophysics Data System (ADS)

Wu, Xiao; Bi, Naishuang; Xu, Jingping; Nittrouer, Jeffrey A.; Yang, Zuosheng; Saito, Yoshiki; Wang, Houjie

2017-09-01

The presently active Yellow River (Huanghe) delta lobe has been formed since 1976 when the river was artificially diverted. The process and driving forces of morphological evolution of the present delta lobe still remain unclear. Here we examined the stepwise morphological evolution of the active Yellow River delta lobe including both the subaerial and the subaqueous components, and illustrated the critical roles of riverine discharge and sediment grain size in dominating the deltaic evolution. The critical sediment loads for maintaining the delta stability were also calculated from water discharge and sediment load measured at station Lijin, the last gauging station approximately 100 km upstream from the river mouth. The results indicated that the development of active delta lobe including both subaerial and subaqueous components has experienced four sequential stages. During the first stage (1976-1981) after the channel migration, the unchannelized river flow enhanced deposition within the channel and floodplain between Lijin station and the river mouth. Therefore, the critical sediment supply calculated by the river inputs obtained from station Lijin was the highest. However, the actual sediment load at this stage (0.84 Gt/yr) was more than twice of the critical sediment load ( 0.35 Gt/yr) for sustaining the active subaerial area, which favored a rapid seaward progradation of the Yellow River subaerial delta. During the second stage (1981-1996), the engineering-facilitated channelized river flow and the increase in median grain size of suspended sediment delivered to the sea resulted in the critical sediment load for keeping the delta stability deceasing to 0.29 Gt/yr. The active delta lobe still gradually prograded seaward at an accretion rate of 11.9 km2/yr at this stage as the annual sediment load at Lijin station was 0.55 Gt/yr. From 1996 to 2002, the critical sediment load further decreased to 0.15 Gt/yr with the sediment grain size increased to 22.5 μm; however, the delta suffered net erosion because of the insufficient sediment supply (0.11 Gt/yr). In the most recent stage (2002 - 2013), the intensive scouring of the lower river channel induced by the dam regulation provided relatively coarser sediment, which effectively reduced the critical sediment load to 0.06 Gt/yr, much lower than the corresponding sediment load at Lijin station ( 0.16 Gt/yr). Consequently, the subaerial Yellow River delta transitioned to a slight accretion phase. Overall, the evolution of the active Yellow River delta is highly correlated to riverine water and sediment discharge. The sediment supply for keeping the subaerial delta stability is inconstant and varying with the river channel morphology and sediment grain size. We conclude that the human-impacted riverine sediment discharge and grain-size composition play dominant roles in the stepwise morphological evolution of the active delta lobe.

Anthropogenic sediment retention: major global impact from registered river impoundments

NASA Astrophysics Data System (ADS)

Vörösmarty, Charles J.; Meybeck, Michel; Fekete, Balázs; Sharma, Keshav; Green, Pamela; Syvitski, James P. M.

2003-10-01

In this paper, we develop and apply a framework for estimating the potential global-scale impact of reservoir construction on riverine sediment transport to the ocean. Using this framework, we discern a large, global-scale, and growing impact from anthropogenic impoundment. Our study links information on 633 of the world's largest reservoirs (LRs) (≥0.5 km 3 maximum storage capacity) to the geography of continental discharge and uses statistical inferences to assess the potential impact of the remaining >44,000 smaller reservoirs (SRs). Information on the LRs was linked to a digitized river network at 30' (latitude×longitude) spatial resolution. A residence time change (Δ τR) for otherwise free-flowing river water is determined locally for each reservoir and used with a sediment retention function to predict the proportion of incident sediment flux trapped within each impoundment. The discharge-weighted mean Δ τR for individual impoundments distributed across the globe is 0.21 years for LRs and 0.011 years for SRs. More than 40% of global river discharge is intercepted locally by the LRs analyzed here, and a significant proportion (≈70%) of this discharge maintains a theoretical sediment trapping efficiency in excess of 50%. Half of all discharge entering LRs shows a local sediment trapping efficiency of 80% or more. Analysis of the recent history of river impoundment reveals that between 1950 and 1968, there was tripling from 5% to 15% in global LR sediment trapping, another doubling to 30% by 1985, and stabilization thereafter. Several large basins such as the Colorado and Nile show nearly complete trapping due to large reservoir construction and flow diversion. From the standpoint of sediment retention rates, the most heavily regulated drainage basins reside in Europe. North America, Africa, and Australia/Oceania are also strongly affected by LRs. Globally, greater than 50% of basin-scale sediment flux in regulated basins is potentially trapped in artificial impoundments, with a discharge-weighted sediment trapping due to LRs of 30%, and an additional contribution of 23% from SRs. If we consider both regulated and unregulated basins, the interception of global sediment flux by all registered reservoirs ( n≈45,000) is conservatively placed at 4-5 Gt year -1 or 25-30% of the total. There is an additional but unknown impact due to still smaller unregistered impoundments ( n≈800,000). Our results demonstrate that river impoundment should now be considered explicitly in global elemental flux studies, such as for water, sediment, carbon, and nutrients. From a global change perspective, the long-term impact of such hydraulic engineering works on the world's coastal zone appears to be significant but has yet to be fully elucidated.

Analysis of Fluvial Bed Sediments Along the Apalachicola River, Florida through Field Reconnaissance Studies

NASA Astrophysics Data System (ADS)

Passeri, D.; Hagen, S. C.; Daranpob, A.; Smar, D. E.

2011-12-01

River competence is an important parameter in understanding sediment transport in fluvial systems. Competence is defined as the measure of a stream's ability to transport a certain maximum grain size of sediment. Studies have shown that bed sediment particle size in rivers and streams tends to vary spatially along the direction of stream flow. Over a river section several reaches long, variability of sediment particle sizes can be seen, often becoming finer downstream. This phenomenon is attributed to mechanisms such as local control of stream gradient, coarse tributary sediment supply or particle breakdown. Average particle size may also be smaller in tributary sections of rivers due to river morphology. The relationship between river mean velocity and particle size that can be transported has also been explored. The Hjulstrom curve classifies this relationship by relating particle size to velocity, dividing the regions of sedimentation, transportation, and erosion. The curve can also be used to find values such as the critical erosion velocity (the velocity required to transport particles of various sizes in suspension) and settling velocity (the velocity at which particles of a given size become too heavy to be transported and fall out of suspension, consequently causing deposition). The purpose of this research is to explore the principles of river competence through field reconnaissance collection and laboratory analysis of fluvial sediment core samples along the Apalachicola River, FL and its distributaries. Sediment core samples were collected in the wetlands and estuarine regions of the Apalachicola River. Sieve and hydrometer analyses were performed to determine the spatial distribution of particle sizes along the river. An existing high resolution hydrodynamic model of the study domain was used to simulate tides and generate river velocities. The Hjulstrom curve and the generated river velocities were used to define whether sediment was being transported, eroded or deposited at the different locations in the river and its distributaries. Parameters such as critical erosion velocity and settling velocity were also calculated to describe sediment transport along the channel. This research provides a better understanding of the fluvial geomorphic system, particularly sediment transport in channels. It also provides excellent validation data for future sediment transport studies in similar fluvial study domains.

Unravelling the relative contribution of bed and suspended sediment load on a large alluvial river

NASA Astrophysics Data System (ADS)

Darby, S. E.; Hackney, C. R.; Parsons, D. R.; Leyland, J.; Aalto, R. E.; Nicholas, A. P.; Best, J.

2017-12-01

The world's largest rivers transport 19 billion tonnes of sediment to the coastal zone annually, often supporting large deltas that rely on this sediment load to maintain their elevation in the face of rising sea level, and to sustain high levels of agricultural productivity and biodiversity. However, the majority of estimates of sediment delivery to coastal regions pertain solely to the suspended fraction of the sediment load, with the bedload fraction often being neglected due to the difficulty in estimating bedload flux and the assumption that bedload contributes a minor (<10%) fraction of the total sediment load. In large rivers, capturing accurate estimates of the suspended- and bed- load fractions is difficult given the large channel widths and depths and the intrusive nature of typical methodologies. Yet, for the successful implementation of sustainable river, and delta, management plans, improved estimates of all fractions of the sediment load are essential. Recent advances in non-intrusive, high-resolution, technology have begun to enable more accurate estimates of bedload transport rates. However, the characterisation of the holistic sediment transport regime of large alluvial rivers is still lacking. Here, we develop a sediment transport rating curve, combining both suspended- and bed- load sediment fractions, for the Lower Mekong River. We define suspended sediment rating curves using the inversion of acoustic return data from a series of acoustic Doppler current profiler surveys conducted through the Lower Mekong River in Cambodia, and into the bifurcating channels of the Mekong delta in Vietnam. Additionally, we detail estimates of bed-load sediment transport determined using repeat multibeam echo sounder surveys of the channel bed. By combining estimates of both fractions of the sediment load, we show the spatial and temporal contribution of bedload to the total sediment load of the Mekong and refine estimates of sediment transport to the Mekong delta. Our results indicate that the time-averaged suspended load transport rates for the Mekong River are 87 MT/yr, whilst bedload transport forms c. < 5% of the total sediment load within the Mekong River. Such estimates are integral to future channel management within this highly threatened river basin.

Toxicity risk assessment of mercury, DDT and arsenic legacy pollution in sediments: A triad approach under low concentration conditions.

PubMed

Marziali, L; Rosignoli, F; Drago, A; Pascariello, S; Valsecchi, L; Rossaro, B; Guzzella, L

2017-09-01

The determination of sediment toxicity is challenging due to site-specific factors affecting pollutants distribution and bioavailability, especially when contamination levels are close to expected non-effect concentrations. Different lines of evidence and sensitive tools are necessary for a proper toxicity risk assessment. We examined the case study of the Toce River (Northern Italy), where past industrial activities determined Hg, DDT and As enrichment in sediments. A triad approach comprising chemical, ecotoxicological and ecological analyses (benthic invertebrates) was carried out for risk assessment of residual contamination in river sediments. A "blank" site upstream from the industrial site was selected to compare the other sites downstream. Sediment, water and benthic invertebrate samplings were carried out following standard protocols. Results emphasized that despite the emissions of the industrial site ceased about 20years ago, sediments in the downstream section of the river remain contaminated by Hg, DDT and As with concentrations exceeding Threshold Effect Concentrations. A chronic whole-sediment test with Chironomus riparius showed decreased development rate and a lower number of eggs per mass in the contaminated sediments. Benthic community was analyzed with the calculation of integrated (STAR_ICMi) and stressor-specific metrics (SPEAR pesticide and mean sensitivity to Hg), but no significant differences were found between upstream and downstream sites. On the other hand, multivariate analysis (partial Redundancy Analysis and variation partitioning) emphasized a slight impact on invertebrate community, accounting for 5% variation in taxa composition. Results show that legacy contaminants in sediments, even at low concentrations, may be bioavailable and possibly toxic for benthic invertebrates. At low concentration levels, sensitive and site-specific tools need to be developed for a proper risk analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Radiocesium decontamination of a riverside in Fukushima, Japan.

PubMed

Nishikiori, Tatsuhiro; Suzuki, Satoshi

2017-10-01

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

Hydro-geomorphology of the middle Elwha River, Washington, following dam removal

NASA Astrophysics Data System (ADS)

Morgan, J. A.; Nelson, P. A.; Brogan, D. J.

2017-12-01

Dam removal is an increasingly common river restoration practice, which can produce dramatic increases in sediment supply to downstream reaches. There remains, however, considerable uncertainty in how mesoscale morphological units (e.g., riffles and pools) respond to the flow and sediment supply changes associated with dam removal. The recent removal of Glines Canyon Dam on the Elwha River in Washington State provides a natural setting to explore how increased sediment supply due to dam removal may affect downstream reaches. Here, we present observations and surveys documenting how a 1 km reach, located approximately 5 km downstream of the former dam site, has evolved following dam removal. Annual topographic/bathymetric surveys were conducted in 2014-2016 using RTK-GNSS methods, and these surveys were coupled with airborne lidar to create continuous surface maps of the valley bottom. Differencing the elevation models reveals channel widening and migration due to lateral bank retreat and bar aggradation. Analysis of aerial imagery dating back to 1939 suggests that rates of both widening and meander migration have increased following dam removal. We also used results from depth-averaged hydrodynamic modeling with a fuzzy c-means clustering approach to delineate riffle and pool units; this analysis suggests that both riffles and pools stayed relatively consistent from 2014-2015, while both areas decreased from 2015 to 2016. Without any considerable changes to the hydrologic regime these higher rates of change are implied to be the result of the increased sediment supply. Our results, which indicate an increased dynamism due directly to the amplified sediment supply, have the potential to further inform river managers and restoration specialists who oversee projects related to changing sediment regimes.

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

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

2005-01-01

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.

Solid transport in mountain rivers: monitoring techniques and long term assessment as flood prevention tools

NASA Astrophysics Data System (ADS)

Longoni, Laura; Brambilla, Davide; Ivanov, Vladislav; Messa, Giacomo; Veronelli, Andrea; Radice, Alessio; Papini, Monica

2017-04-01

Floods are calamitous phenomena with an ever-increasing frequency around the globe, that often result in socio-economic damage and casualties. The role of the solid fraction in the river dynamic has been widely debated in the last decade and its importance is recognized as critical and not negligible in flood simulations as it has been evidenced that the severity of an event is often the result of the coupling of a flood wave with elevated solid transport rates. Nevertheless, assessing the quantity of sediment mobilized in a particular event is not feasible without a long term analysis of the river's dynamics and its morphological evolution since it is defined by past events. This work is focused on the techniques to improve knowledge about sediment production and transport through hydrological networks as a necessary component of a wise flood prevention planning. In particular, a multidisciplinary approach that combines hydraulic and geological knowledge is required in order to understand the evolution of the river sediment and how it will influence the following critical event. The methods are presented through a case study in Italy where a series of different approaches have been integrated to gain a comprehensive understanding of the problem: the sediment movement has been studied by a Eulerian as well as a Lagrangian approaches while hydraulic properties of the stream have been measured. The research started with an attempt to monitor sediment movements: in June 2016 300 sample pebbles, equipped with RFID (Radio Frequency IDentification) transponders, have been deployed in the river and tracked after every major rainfall event. The obtained data-set has been combined with a morphological analysis and a river flow discharge computed through PIV (Particle Image Velocimetry) method in order to identify the relation between a given rainfall event and sediment transport. Moreover, critical sediment size has been estimated from field data using three approaches: two experimental performed in situ and one analytical using hydraulic modelling. A good correlation between the results of these approaches has been obtained, while the results of the solid transport analysis suggest that the migration of sediments appears to be affected to a large extent by the river bed morphology in addition to the physical properties of the pebbles. Finally, a control section has been set up in a sedimentation basin which limits the further sediment migration to the downstream end of the river. Therefore, it was considered the perfect point to measure the final solid discharge of an event. Several bathymetric campaigns have been carried out to assess the gross quantity of material discharged in the pool. The use of a wireless Eco sounder has been tested along with a conventional GPR (Ground Penetrating Radar) in order to investigate the applicability of a low-cost tool for bathymetry survey in a fast and reliable way.

Cadmium mobility in sediments and soils from a coal mining area on Tibagi River watershed: environmental risk assessment.

PubMed

Galunin, Evgeny; Ferreti, Jeferson; Zapelini, Iago; Vieira, Isadora; Ricardo Teixeira Tarley, César; Abrão, Taufik; Santos, Maria Josefa

2014-01-30

The risk of cadmium contamination in the Tibagi River watershed (Parana State, Brazil) affected by past coal mining activities was assessed through sorption-desorption modeling for sediment and soil samples. The acidic character of the samples resulted in more competition between the cadmium ions and protons, thereby influencing the cadmium sorption-desorption. The sorption isotherms were fitted to the Langmuir and Freundlich single models and to the dual-site Langmuir-Freundlich (or Sips) model. The single-site models indicated a low-energy character of sorption sites on the sample sorption sites, whereas the dual-site model explained the availability of higher-affinity and lower-affinity non-specific sites. The correlation of the sorption and desorption constants with the physicochemical and mineralogical characteristics of the samples showed that the cadmium sorption behavior was significantly affected by the pH, point of zero charge, and also by the magnesium, aluminum, calcium and manganese amounts. Besides, the desorption rate and hysteresis index suggested a high risk of cadmium mobilization along the Tibagi River basin. Copyright © 2013 Elsevier B.V. All rights reserved.

Sediment, land use, and freshwater mussels: Prospects and problems

USGS Publications Warehouse

Brim-Box, J.; Mossa, J.

1999-01-01

The decline in freshwater mussel populations in many river basins throughout North America has been attributed, in part, to land-use modifications that cause changes in sediment regimes. However, the specific associations that mussels have with stream sediments are poorly understood, making it difficult to assess the impacts of changes in sedimentation rates on unionid mussels. Both bed and suspended materials, and concomitant changes in channel form associated with changes in sediment supply, may affect mussels in numerous ways at various stages in their life cycle. Considerable debate and uncertainty remains regarding the strength of associations between sediments and mussels, including whether increased sedimentation is a cause of recent mussel declines. It is important to be aware of appropriate procedures for sampling and analyzing fluvial sediments, and the nature of sediment sources, to adequately assess relationships between unionid mussels and fluvial sediments.

Ephemeral seafloor sedimentation during dam removal: Elwha River, Washington

USGS Publications Warehouse

Foley, Melissa M.; Warrick, Jonathan

2017-01-01

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

Effects of sediment cover on survival and development of white sturgeon embryos

USGS Publications Warehouse

Kock, T.J.; Congleton, J.L.; Anders, P.J.

2006-01-01

A simple, inexpensive apparatus (embryo incubation unit [EIU]) was developed and used to assess the relationship between sediment cover (Kootenai River sediments, 97% by weight in the 0.83-mm- to 1.0-mm-diameter range) and survival of white sturgeon Acipenser transmontanus embryos in the laboratory. An apparatus-testing trial assessed the effects of two sediment depths (5 and 20 mm), three EIU ventilation hole sizes (4.8, 6.8, and 9.5 mm) providing three levels of intrasediment flow, and EIU location (upstream or downstream in laboratory troughs) on embryo survival at two above-substrate flow velocities (0.05 and 0.15 m/s). A second trial assessed the effects of sediment cover duration (5-mm sediment cover for 4, 7, 9, 11, or 14 d, with a ventilation hole size of 9.5 mm and a flow velocity of 0.17 m/s) on mean embryo survival and larval length and weight. In the apparatus-testing trial, embryo survival was reduced (P < 0.0001) to 0-5% under sediment covers of either 5 or 20 mm in both the higher-flow and lower-flow troughs; survival in control EIUs without sediments exceeded 80%. Survival was not significantly affected by ventilation hole size but was weakly affected by EIU location. In the second trial, embryo survival was negatively correlated (P = 0.001) with increasing duration of sediment cover and was significantly higher for embryos covered for 4 d (50% survival) or 7 d (30% survival) than for those covered for 9, 11, or 14 d (15-20% survival). Sediment cover also delayed hatch timing (P < 0.0001) and decreased mean larval length (P < 0.0001). Our results suggest that sediment cover may be an important early life stage mortality factor in rivers where white sturgeon spawn over fine-sediment substrates. ?? Copyright by the American Fisheries Society 2006.

Interpreting the suspended sediment dynamics in a mesoscale river basin of Central Mexico using a nested watershed approach

NASA Astrophysics Data System (ADS)

Duvert, C.; Némery, J.; Gratiot, N.; Prat, C.; Collet, L.; Esteves, M.

2009-12-01

The Cointzio river basin is located within the Mexican Transvolcanic Belt, in the Michoacán state. Land-use changes undergone over last decades lead to significant erosion processes, though affecting limited areas of the basin. Apart from generating a minor depletion of arable land by incising small headwater areas, this important sediment delivery contributed to siltation in the reservoir of Cointzio, situated right downstream of the basin. During 2009 rainy season, a detailed monitoring of water and sediment fluxes was undertaken in three headwater catchments located within the Cointzio basin (Huertitas, Potrerillos and La Cortina, respectively 2.5, 9.3 and 12.0 km2), as well as at the outlet of the main river basin (station of Santiago Undameo, 627 km2). Preliminary tests realized in 2008 underlined the necessity of carrying out a high-frequency monitoring strategy to assess the sediment dynamics in the basins of this region. In each site, water discharge time-series were obtained from continuous water-level measurements (5-min time-step), and stage-discharge rating curves. At the river basin outlet, Suspended Sediment Concentration (SSC) was estimated every 10 minutes through turbidity measurements calibrated with data from automatic sampling. In the three sub-catchments, SSC time-series were calculated using stage-triggered automatic water samplers. The three upland areas monitored in our study present distinct landforms, morphology and soil types. La Cortina is underlain by andisols, rich in organic matter and with an excellent microstructure under wet conditions. Huertitas and Potrerillos both present a severely gullied landscape, bare and highly susceptible to water erosion in degraded areas. As a result, suspended sediment yields in 2009 were expectedly much higher in these two sub-catchments (≈320 t.km-2 in Huertitas and ≈270 t.km-2 in Potrerillos) than in La Cortina (≈40 t.km-2). The total suspended sediment export was approximately of 30 t.km-2 at the outlet, with a dominance of cohesive sediments (mainly silt and clay). Sediment delivery dynamics was found to be seasonally dependent and principally driven by the river network transport capacity. With the exception of events associated with a very high discharge peak, sub-catchments delivered very little sediment to the basin’s outlet during first events of the rainy season (corresponding to May-June period). Later on (from July until the end of the season), even low headwater sediment peaks were coupled with significant sediment fluxes at the outlet. An analysis of SSC-Q hysteresis patterns was also conducted for major flood events at each site. Anti-clockwise SSC-Q hysteresis loops were recorded most frequently at the three upland sub-catchments, while at the outlet a double-peaked SSC signal was repeatedly detected, outlining the variety in sediment contributions. The findings of this nested watershed approach suggest that during the first part of the rainy season, fine sediment loads exported from active hillslopes deposit as fluid mud layers in the lowland river channels. Once the in-channel storage capacity is loaded, the river transport potential guarantees a direct transit between headwater areas and delivery zones.

Metagenomic analysis of the bacterial communities and their functional profiles in water and sediments of the Apies River, South Africa, as a function of land use.

PubMed

Abia, Akebe Luther King; Alisoltani, Arghavan; Keshri, Jitendra; Ubomba-Jaswa, Eunice

2018-03-01

Water quality is an important public health issue given that the presence of pathogenic organisms in such waters can adversely affect human and animal health. Despite the numerous studies conducted to assess the quality of environmental waters in many countries, limited efforts have been put on investigating the microbial quality of the sediments in developing countries and how this relates to different land uses. The present study evaluated the bacterial diversity in water and sediments in a highly used South African river to find out how the different land uses influenced the bacterial diversity, and to verify the human diseases functional classes of the bacterial populations. Samples were collected on river stretches influenced by an informal, a peri-urban and a rural settlement. Genomic DNA was extracted from water and sediment samples and sequenced on an Illumina® MiSeq platform targeting the 16S rRNA gene variable region V3-V4 from the genomic DNA. Metagenomic data analysis revealed that there was a great diversity in the microbial populations associated with the different land uses, with the informal settlement having the most considerable influence on the bacterial diversity in the water and sediments of the Apies River. The Proteobacteria (69.8%), Cyanobacteria (4.3%), Bacteroidetes (2.7%), and Actinobacteria (2.7%) were the most abundant phyla; the Alphaproteobacteria, Betaproteobacteria and Anaerolineae were the most recorded classes. Also, the sediments had a greater diversity and abundance in bacterial population than the water column. The functional profiles of the bacterial populations revealed an association with many human diseases including cancer pathways. Further studies that would isolate these potentially pathogenic organisms in the aquatic environment are therefore needed as this would help in protecting the lives of communities using such rivers, especially against emerging bacterial pathogens. Copyright © 2017 Elsevier B.V. All rights reserved.

Bedload pulses in a hydropower affected alpine gravel bed river

NASA Astrophysics Data System (ADS)

Aigner, Johann; Kreisler, Andrea; Rindler, Rolf; Hauer, Christoph; Habersack, Helmut

2017-08-01

This study investigated the sediment resupply and transport dynamics at the Upper Drau River upstream of Lienz (Eastern Tyrol, Austria). Due to a hydropower plant, a 24 km long river reach of this alpine gravel bed river is under residual flow conditions, although sediment is still resupplied into the reach through many active torrents and tributaries. As a result, sediment deposition in the residual flow reach intensified, hence increasing maintenance efforts to stabilize this river section and ensure flood protection. In combination with a new sediment management program, a continuous bedload monitoring system was installed 2 km downstream of the residual reach in 2001 to support the development of adapted sediment management strategies. The surrogate bedload monitoring system consists of 16 impact plate geophones, installed over a 17 m wide cross section. The unprecedented 15-year dataset of high-resolution bedload intensity revealed a complex process of gravel storage and intermittent resupply from the residual reach, allowing the authors a detailed analysis of frequently occurring bedload pulses. These transport features are triggered by increased discharges during floods in the residual reach and created pronounced anticlockwise bedload hysteresis or, with a temporal shift to the event peak, caused distinct shifts in the bedload activity downstream. Bedload pulses produce very high bedload fluxes while in transit, tend to increase bedload flux in the post-event phase, and can alter and reduce the upstream sediment storage leading to a lowering of bedload availability for future pulses. The observed time lags between main discharge events and the arrival of the macro-pulses are correlated with mean water discharge during pulse propagation, thus enabling a prediction of the pulse arrival at the monitoring station solely based on the hydrograph. In combination with the hydrological setup of the reach, the observed bedload pulse time lags allowed an estimation of pulse velocities in the range 0.002 - 0.05 m s- 1.

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

Bratkič, Arne, E-mail: arne.bratkic@ijs.si; Ogrinc, Nives, E-mail: nives.orginc@ijs.si; Kotnik, Jože, E-mail: joze.kotnik@ijs.si

In this study, seasonal changes of mercury (Hg) species in the highly variable estuary of Soča/Isonzo River (northern Adriatic Sea) were investigated. Samplings were performed on a seasonal basis (September 2009, May, August and October 2010) and Hg species (total Hg, methylmercury (MeHg), dissolved gaseous Hg (DGM)) in waters, sediments and pore waters were determined. In addition, a range of ancillary parameters were measured (salinity, nutrients, organic carbon (OC), nitrogen species). Hg values were interpreted using these parameters and hydrological conditions (river flow, wave height) around the time of sampling. There were no significant changes in Hg load from rivermore » to the gulf, compared to previous studies. The load was temporarily higher in May 2010 due to higher river flow. Wave height, through changing hydrostatic pressure, was most likely to cause resuspension of already deposited Hg from the bottom (August 2010). The estuary is a net source of DGM to the atmosphere as suggested by DGM profiles, with salinity, redox potential and organic matter as the most probable controls over its production. MeHg is produced in situ in sediment or in water column, rather than transported by river, as indicated by its correlation with OC of the marine origin. Calculated fluxes for THg and MeHg showed sediment as a source for both the water column. In pore waters, OC in part affects partitioning of both THg and MeHg; however other factors (e.g. sulphide and/or oxyhydroxides precipitation and dissolution) are also probably important. -- Highlights: ► Water, sediment and pore water mercury species in front of Soča River estuary were measured. ► Seasonally variable hydrological conditions were shown to influence water column Hg speciation. ► Fluxes for total Hg and MeHg from sediment to water were calculated. ► Sediment is a source of total Hg and MeHg to the water column. ► Correlation of MeHg with organic carbon of marine origin suggests in situ formation.« less

Environmental and human impact on the sedimentary dynamic in the Rhone Delta subaquatic canyons (France-Switzerland)

NASA Astrophysics Data System (ADS)

Arantegui, A.; Corella, J. P.; Loizeau, J. L.; Anselmetti, F. S.; Girardclos, S.

2012-04-01

Deltas are very sensitive environments and highly vulnerable to variations in water discharge and the amount of suspended sediment load provided by the delta-forming currents. Human activities in the watershed, such as building of dams and irrigation ditches, or river bed deviations, may affect the discharge regime and sediment input, thus affecting delta growth. Underwater currents create deeply incised canyons cutting into the delta lobes. Understanding the sedimentary processes in these subaquatic canyons is crucial to reconstruct the fluvial evolution and human impact on deltaic environments and to carry out a geological risk assessment related to mass movements, which may affect underwater structures and civil infractructure. Recently acquired high-resolution multibeam bathymetry on the Rhone Delta in Lake Geneva (Sastre et al. 2010) revealed the complexity of the underwater morphology formed by active and inactive canyons first described by Forel (1892). In order to unravel the sedimentary processes and sedimentary evolution in these canyons, 27 sediment cores were retrieved in the distal part of each canyon and in the canyon floor/levee complex of the active canyon. Geophysical, sedimentological, geochemical and radiometric dating techniques were applied to analyse these cores. Preliminary data show that only the canyon originating at the current river mouth is active nowadays, while the others remain inactive since engineering works in the watershed occurred, confirming Sastre et al. (2010). However, alternating hemipelagic and turbiditic deposits on the easternmost canyons, evidence underflow processes during the last decades as well. Two canyons, which are located close to the Rhone river mouth, correspond to particularly interesting deeply incised crevasse channels formed when the underwater current broke through the outer bend of a meander in the proximal northern levee. In these canyons, turbidites occur in the sediment record indicating ongoing sediment dynamics during whether extreme flood events or mass-movements due to deltaic scarp failures. The active canyon shows a classic turbiditic system with frequent spillover processes in the canyon floor/levee complex. Geotechnical measurements, a decrease in the frequency of turbidites and a fining upward sequence along the levee suggest that erosion dominates sedimentation in the canyon floor, while sedimentation dominates in the rapid levee building-up process, with sedimentation rates that exceed 3cm/yr in the proximal areas. Therefore, mechanisms controlling the sedimentary evolution on the active canyon result in a complex interplay between erosion and sedimentation. Further research will provide a detailed evaluation of the human impact on sedimentary dynamic in the Rhone Delta subaquatic canyons.

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

PubMed

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

2006-05-01

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

A Review of Flood-Related Storage and Remobilization of Heavy Metal Pollutants in River Systems.

PubMed

Ciszewski, Dariusz; Grygar, Tomáš Matys

Recently observed rapid climate changes have focused the attention of researchers and river managers on the possible effects of increased flooding frequency on the mobilization and redistribution of historical pollutants within some river systems. This text summarizes regularities in the flood-related transport, channel-to-floodplain transfer, and storage and remobilization of heavy metals, which are the most persistent environmental pollutants in river systems. Metal-dispersal processes are essentially much more variable in alluvia than in soils of non-inundated areas due to the effects of flood-sediment sorting and the mixing of pollutants with grains of different origins in a catchment, resulting in changes of one to two orders of magnitude in metal content over distances of centimetres. Furthermore, metal remobilization can be more intensive in alluvia than in soils as a result of bank erosion, prolonged floodplain inundation associated with reducing conditions alternating with oxygen-driven processes of dry periods and frequent water-table fluctuations, which affect the distribution of metals at low-lying strata. Moreover, metal storage and remobilization are controlled by river channelization, but their influence depends on the period and extent of the engineering works. Generally, artificial structures such as groynes, dams or cut-off channels performed before pollution periods favour the entrapment of polluted sediments, whereas the floodplains of lined river channels that adjust to new, post-channelization hydraulic conditions become a permanent sink for fine polluted sediments, which accumulate solely during overbank flows. Metal mobilization in such floodplains takes place only by slow leaching, and their sediments, which accrete at a moderate rate, are the best archives of the catchment pollution with heavy metals.

Oceanic loading of wildfire-derived organic compounds from a small mountainous river

USGS Publications Warehouse

Hunsinger, G.B.; Mitra, Siddhartha; Warrick, J.A.; Alexander, C.R.

2008-01-01

Small mountainous rivers (SMRs) export substantial amounts of sediment into the world's oceans. The concomitant yield of organic carbon (OC) associated with this class of rivers has also been shown to be significant and compositionally unique. We report here excessively high loadings of polycyclic aromatic hydrocarbons (PAHs), lignin, and levoglucosan, discharged from the Santa Clara River into the Santa Barbara Channel. The abundance of PAHs, levoglucosan, and lignin in Santa Barbara Channel sediments ranged from 201.7 to 1232.3 ng gdw-1, 1.3 to 6.9 ??g gdw-1, and 0.3 to 2.2 mg per 100 mg of the sedimentary OC, respectively. Assuming a constant rate of sediment accumulation, the annual fluxes of PAHs, levoglucosan, and lignin, to the Santa Barbara Channel were respectively, 885.5 ?? 170.2 ng cm-2 a-1, 3.5 ?? 1.9 ??g cm-2 a-1 and 1.4 ?? 0.3 mg per 100 mg OC cm-2 a-1, over ???30 years. The close agreement between PAHs, levoglucosan, and lignin abundance suggests that the depositional flux of these compounds is largely biomass combustion-derived. To that end, use of the Santa Clara River as a model for SMRs suggests this class of rivers may be one of the largest contributors of pyrolyzed carbon to coastal systems and the open ocean. Wildfire associated carbon discharged from other high yield fluvial systems, when considered collectively, may be a significant source of lignin, pyrolytic PAHs, and other pyrogenic compounds to the ocean. Extrapolating these methods over geologic time may offer useful historical information about carbon sequestration and burial in coastal sediments and affect coastal carbon budgets. Copyright 2008 by the American Geophysical Union.

Distribution and pollution, toxicity and risk assessment of heavy metals in sediments from urban and rural rivers of the Pearl River delta in southern China.

PubMed

Xiao, Rong; Bai, Junhong; Huang, Laibin; Zhang, Honggang; Cui, Baoshan; Liu, Xinhui

2013-12-01

Sediments were collected from the upper, middle and lower reaches of both urban and rural rivers in a typical urbanization zone of the Pearl River delta. Six heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) were analyzed in all sediment samples, and their spatial distribution, pollution levels, toxicity and ecological risk levels were evaluated to compare the characteristics of heavy metal pollution between the two rivers. Our results indicated that the total contents of the six metals in all samples exceeded the soil background value in Guangdong province. Based on the soil quality thresholds of the China SEPA, Cd levels at all sites exceeded class III criteria, and other metals exhibited pollution levels exceeding class II or III criteria at both river sites. According to the sediment quality guidelines of the US EPA, all samples were moderately to heavily polluted by Cr, Cu, Ni, Pb and Zn. Compared to rural river sites, urban river sites exhibited heavier pollution. Almost all sediment samples from both rivers exhibited moderate to serious toxicity to the environment, with higher contributions from Cr and Ni. A "hot area" of heavy metal pollution being observed in the upper and middle reaches of the urban river area, whereas a "hot spot" was identified at a specific site in the middle reach of the rural river. Contrary metal distribution patterns were also observed along typical sediment profiles from urban and rural rivers. However, the potential ecological risk indices of rural river sediments in this study were equal to those of urban river sediments, implying that the ecological health issues of the rivers in the undeveloped rural area should also be addressed. Sediment organic matter and grain size might be important factors influencing the distribution profiles of these heavy metals.

Suspended-sediment and fresh-water discharges in the Ob and Yenisey rivers, 1960-1988

USGS Publications Warehouse

Meade, R.H.; Bobrovitskaya, N.N.; Babkin, V.I.

2000-01-01

Of the world's great rivers, the Ob and Yenisey rank among the largest suppliers of fresh water and among the smallest suppliers of suspended sediment to the coastal ocean. Sediment in the middle reaches of the rivers is mobilized from bordering terraces and exchanged between channels and flood plains. Sediment in the lower reaches of these great rivers is deposited and stored (permanently, on a millennial time scale) in flood plains. Sediment discharges, already small under natural conditions, are diminished further by large manmade reservoirs that trap significant proportions of the moving solids. The long winter freeze and sudden spring breakup impose a peakedness in seasonal water runoff and sediment discharge that contrasts markedly with that in rivers of the tropics and more temperate climates. Very little sediment from the Ob and Yenisey rivers is being transported to the open waters of the Arctic Ocean under present conditions.

Water quality changes and their relation to fishery resources in the upper Mississippi River

USGS Publications Warehouse

Holland Bartels, L. E.; Becker, C.D.; Neitzel, D.A.

1992-01-01

Despite a long history of human manipulation, the most dramatic changes in the upper Mississippi River occurred in the 1930s with construction of a lock and dam system to facilitate the commercial transport of commodities. In 1988, barge traffic through the system ranged from 7,500 tows per year at Lock and Dam 26 (near Alton, Illinois) to 1, 118 at Lock and Dam 1 (in Minneapolis/St. Paul). The tow-teed dam system created a diversity of lentic habitats, but it also changed the stage and sediment transport characteristics of the river. The principal fishery-related water quality issues of this modified system concern the effects of sediments and toxic contaminants from nonpoint sources. Between 42 and 99% of the streams in the five states of the Mississippi River basin fail to fully support their designated uses because of pollution. primarily from nonpoint sources (e.g., 73% in Minnesota, 98% in Wisconsin, 75% in Illinois). Annual sediment inputs into the upper Mississippi River basin range from minimal in the upper reaches to about 210.000 kg/hectare in the lower reaches. This sediment results in significant losses of fishery habitat. Although bnly 5 to 9% of the total open water area of many pools had been lost by 1975, those losses were in highly productive side channel and backwater areas. Under existing conditions, a loss of an additional 22 to 49% of existing lentic habitats is predicted within 50 years. In addition, toxic contaminants transported along with fine sediments have become more available to stream biota. Although significant interagency efforts have been made to evaluate the impacts on biotic communities of the river. present data are inadequate to determine how changes in water quality affect the fisheries. This lack of data undermines our ability to judge the success of programs initiated to control pollution from point and nonpoint sources.

Identifying water-quality trends in the Trinity River, Texas, USA, 1969-1992, using sediment cores from Lake Livingston

USGS Publications Warehouse

Van Metre, P.C.; Callender, E.

1996-01-01

Chemical analyses were done on cores of bottom sediment from three locations in Lake Livingston, a reservoir on the Trinity River in east Texas to identify trends in water quality in the Trinity River using the chemical record preserved in bottom sediments trapped by the reservoir. Sediment cores spanned the period from 1969, when the reservoir was impounded, to 1992, when the cores were collected. Chemical concentrations in reservoir sediment samples were compared to concentrations for 14 streambed sediment samples from the Trinity River Basin and to reported concentrations for soils in the eastern United States and shale. These comparisons indicate that sediments deposited in Lake Livingston are representative of the environmental setting of Lake Livingston within the Trinity River Basin. Vertical changes in concentrations within sediment cores indicate temporal trends of decreasing concentrations of lead, sodium, barium, and total DDT (DDT plus its metabolites DDD and DDE) in the Trinity River. Possible increasing temporal trends are indicated for chlordane and dieldrin. Each sediment-derived trend is related to trends in water quality in the Trinity River or known changes in environmental factors in its drainage basin or both.

Generalized sediment budgets of the Lower Missouri River, 1968–2014

USGS Publications Warehouse

Heimann, David C.

2016-09-13

Sediment budgets of the Lower Missouri River were developed in a study led by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers. The scope of the study included the development of a long-term (post-impoundment, 1968–2014) average annual sediment budget and selected annual, monthly, and daily sediment budgets for a reach and period that adequate data were available. Included in the analyses were 31 main-stem and tributary stations of the Lower Missouri River and two Mississippi River stations—the Mississippi River below Grafton, Illinois, and the Mississippi River at St. Louis, Missouri.Long-term average annual suspended-sediment loads of Missouri River main-stem stations ranged from 0.33 million tons at the Missouri River at Yankton, South Dakota, station to 71.2 million tons at Missouri River at Hermann, Mo., station. Gaged tributary gains accounted for 9–36 percent of the local reach budgets and cumulative gaged tributary contributions accounted for 84 percent of the long-term average suspended-sediment load of the Missouri River at Hermann, Mo., station. Although the sediment budgets for seven defined main-stem reaches generally were incomplete—missing bedload, reach storage, and ungaged tributary contributions—the budget residuals (net result of sediment inputs and outputs) for six of the seven reaches ranged from -7.0 to 1.7 million tons, or from -9.2 to 4.0 percent of the reach output suspended-sediment load, and were within the 10 percent reported measurement error of annual suspended-sediment loads for large rivers. The remaining reach, downstream from Gavin’s Point Dam, extended from Yankton, S. Dak., to Sioux City, Iowa, and had a budget residual of -9.8 million tons, which was -88 percent of the suspended-sediment load at Sioux City.The Lower Missouri River reach from Omaha, Nebraska, to Nebraska City, Nebr., had periods of concurrent sediment data for each primary budget component with which to analyze and determine a suspended-sediment budget for selected annual, monthly, and daily time increments. The temporal changes in the cumulative annual budget residuals were poorly correlated with the comparatively steady 1968–2011 annual stage trends at the Missouri River at Nebraska City, Nebr., station. An accurate total sediment budget is developed by having concurrent data available for all primary suspended and bedload components for a reach of interest throughout a period. Such a complete budget, with concurrent record for suspended-sediment load and bedload components, is unavailable for any reach and period in the Lower Missouri River. The primary data gaps are in bedload data, and also in suspended-sediment gains and losses including ungaged tributary inputs and sediment storage. Bedload data gaps in the Missouri River Basin are much more prevalent than suspended-sediment data gaps, and the first step in the development of reach bedload budgets is the establishment of a standardized bedload monitoring program at main-stem stations.The temporal changes in flow-adjusted suspended-sediment concentrations analyzed at main-stem Missouri River stations indicated an overall downward change in concentrations between 1968 and 2014. Temporary declines in flow-adjusted suspended-sediment concentrations during and following large floods were evident but generally returned to near pre-flood values within about 6 months.Data uncertainties associated with the development of a sediment budget include uncertainties associated with the collection of suspended-sediment and bedload data and the computation of suspended-sediment loads. These uncertainties vary depending on the frequency of data collection, the variability of conditions being represented by the discrete samples, and the statistical approach to suspended-sediment load computations. The coefficients of variation of suspended-sediment loads of Missouri River tributary stations for 1968–2014 were greater, 75.0 percent, than the main-stem stations, 47.1 percent. The lower coefficient of variation at main-stem stations compared to tributaries, primarily is the result of the lower variability in streamflow and sediment discharge identified at main-stem stations. To obtain similar accuracy between suspended-sediment loads at main-stem and tributary stations, a longer period of record is required of the tributary stations. During 1968–2014, however, the Missouri River main-stem station record was much more complete (87 percent) than the tributary station record (28 percent).

Quantitative mineralogy of the Yukon River system: Changes with reach and season, and determining sediment provenance

USGS Publications Warehouse

Eberl, D.D.

2004-01-01

The mineralogy of Yukon River basin sediment has been studied by quantitative X-ray diffraction. Bed, beach, bar, and suspended sediments were analyzed using the RockJock computer program. The bed sediments were collected from the main stem and from selected tributaries during a single trip down river, from Whitehorse to the Yukon River delta, during the summer of 2001. Beach and bar sediments were collected from the confluence region of the Tanana and Yukon Rivers during the summer of 2003. Suspended sediments were collected at three stations on the Yukon River and from a single station on the Tanana River at various times during the summers of 2001 through 2003, with the most complete set of samples collected during the summer of 2002. Changes in mineralogy of Yukon River bed sediments are related to sediment dilution or concentration effects from tributary sediment and to chemical weathering during transport. Carbonate minerals compose about 2 wt% of the bed sediments near Whitehorse, but increase to 14 wt% with the entry of the White River tributary above Dawson. Thereafter, the proportion of carbonate minerals decreases downstream to values of about 1 to 7 wt% near the mouth of the Yukon River. Quartz and feldspar contents of bed sediments vary greatly with the introduction of Pelly River and White River sediments, but thereafter either increase irregularly (quartz from 20 to about 50 wt%) or remain relatively constant (feldspar at about 35 wt%) with distance downstream. Clay mineral content increases irregularly downstream from about 15 to about 30 wt%. The chief clay mineral is chlorite, followed by illite + smectite; there is little to no kaolinite. The total organic carbon content of the bed sediments remains relatively constant with distance for the main stem (generally 1 to 2 wt%, with one exception), but fluctuates for the tributaries (1 to 6 wt%). The mineralogies of the suspended sediments and sediment flow data were used to calculate the amount of mineral dissolution during transport between Eagle and Pilot Station, a distance of over 2000 km. We estimate that approximately 3 wt% of the quartz, 15 wt% of the feldspar (1 wt% of the alkali and 25 wt% of the plagioclase), and 26 wt% of the carbonates (31 wt% of the calcite and 15 wt% of the dolomite) carried by the river dissolve in this reach. The mineralogies of the suspended sediments change with the season. For example, during the summer of 2002 the quartz content varied by 20 wt%, with a minimum in mid-summer. The calcite content varied by a similar amount, and had a maximum corresponding to the quartz minimum. These modes are related to the relative amount of sediment flowing from the White River system, which is relatively poor in quartz, but rich in carbonate minerals. Suspended total clay minerals varied by as much as 25 wt%, with maxima in mid July, and suspended feldspar varied up to 10 wt%. Suspended sediment data from the summers of 2001 and 2003 support the 2002 trends. A calculation technique was developed to determine theproportion of various sediment sources in a mixed sediment by unmixing its quantitative mineralogy. Results from this method indicate that at least three sediment sources can be identified quantitatively with good accuracy. With this technique, sediment mineralogies can be used to calculate the relative flux of sediment from different tributaries, thereby identifying sediment provenance.

Microbial Remobilisation on Riverbed Sediment Disturbance in Experimental Flumes and a Human-Impacted River: Implication for Water Resource Management and Public Health in Developing Sub-Saharan African Countries

PubMed Central

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

2017-01-01

Resuspension of sediment-borne microorganisms (including pathogens) into the water column could increase the health risk for those using river water for different purposes. In the present work, we (1) investigated the effect of sediment disturbance on microbial resuspension from riverbed sediments in laboratory flow-chambers and in the Apies River, Gauteng, South Africa; and (2) estimated flow conditions for sediment-borne microorganism entrainment/resuspension in the river. For mechanical disturbance, the top 2 cm of the sediment in flow-chambers was manually stirred. Simulating sudden discharge into the river, water (3 L) was poured within 30 s into the chambers at a 45° angle to the chamber width. In the field, sediment was disturbed by raking the riverbed and by cows crossing in the river. Water samples before and after sediment disturbance were analysed for Escherichia coli. Sediment disturbance caused an increase in water E. coli counts by up to 7.9–35.8 times original values. Using Shields criterion, river-flow of 0.15–0.69 m3/s could cause bed particle entrainment; while ~1.57–7.23 m3/s would cause resuspension. Thus, sediment disturbance in the Apies River would resuspend E. coli (and pathogens), with possible negative health implications for communities using such water. Therefore, monitoring surface water bodies should include microbial sediment quality. PMID:28295001

Microbial Remobilisation on Riverbed Sediment Disturbance in Experimental Flumes and a Human-Impacted River: Implication for Water Resource Management and Public Health in Developing Sub-Saharan African Countries.

PubMed

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

2017-03-15

Resuspension of sediment-borne microorganisms (including pathogens) into the water column could increase the health risk for those using river water for different purposes. In the present work, we (1) investigated the effect of sediment disturbance on microbial resuspension from riverbed sediments in laboratory flow-chambers and in the Apies River, Gauteng, South Africa; and (2) estimated flow conditions for sediment-borne microorganism entrainment/resuspension in the river. For mechanical disturbance, the top 2 cm of the sediment in flow-chambers was manually stirred. Simulating sudden discharge into the river, water (3 L) was poured within 30 s into the chambers at a 45° angle to the chamber width. In the field, sediment was disturbed by raking the riverbed and by cows crossing in the river. Water samples before and after sediment disturbance were analysed for Escherichia coli. Sediment disturbance caused an increase in water E. coli counts by up to 7.9-35.8 times original values. Using Shields criterion, river-flow of 0.15-0.69 m³/s could cause bed particle entrainment; while ~1.57-7.23 m³/s would cause resuspension. Thus, sediment disturbance in the Apies River would resuspend E. coli (and pathogens), with possible negative health implications for communities using such water. Therefore, monitoring surface water bodies should include microbial sediment quality.

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

NASA Astrophysics Data System (ADS)

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

2012-05-01

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

Modeling sediment transport with an integrated view of the biofilm effects

NASA Astrophysics Data System (ADS)

Fang, H. W.; Lai, H. J.; Cheng, W.; Huang, L.; He, G. J.

2017-09-01

Most natural sediment is invariably covered by biofilms in reservoirs and lakes, which have significant influence on bed form dynamics and sediment transport, and also play a crucial role in natural river evolution, pollutant transport, and habitat changes. However, most models for sediment transport are based on experiments using clean sediments without biological materials. In this study, a three-dimensional mathematical model of hydrodynamics and sediment transport is presented with a comprehensive consideration of the biofilm effects. The changes of the bed resistance mainly due to the different bed form dynamics of the biofilm-coated sediment (biosediment), which affect the hydrodynamic characteristics, are considered. Moreover, the variations of parameters related to sediment transport after the biofilm growth are integrated, including the significant changes of the incipient velocity, settling velocity, reference concentration, and equilibrium bed load transport rate. The proposed model is applied to evaluate the effects of biofilms on the hydrodynamic characteristics and sediment transport in laboratory experiments. Results indicate that the mean velocity increases after the biofilm growth, and the turbulence intensity near the river bed decreases under the same flow condition. Meanwhile, biofilm inhibits sediment from moving independently. Thus, the moderate erosion is observed for biosediment resulting in smaller suspended sediment concentrations. The proposed model can reasonably reflect these sediment transport characteristics with biofilms, and the approach to integration of the biological impact could also be used in other modeling of sediment transport, which can be further applied to provide references for the integrated management of natural aqueous systems.

Purus River suspended sediment variability and contributions to the Amazon River from satellite data (2000-2015)

NASA Astrophysics Data System (ADS)

Santos, Andre Luis Martinelli Real dos; Martinez, Jean Michel; Filizola, Naziano Pantoja; Armijos, Elisa; Alves, Luna Gripp Simões

2018-01-01

The Purus River is one of the major tributaries of Solimões River in Brazil, draining an area of 370,091 km2 and stretching over 2765 km. Unlike those of the other main tributaries of the Amazon River, the Purus River's sediment discharge is poorly characterized. In this study, as an alternative to the logistic difficulties and considering high monitoring costs, we report an experiment where field measurement data and 2700 satellite (MODIS) images are combined to retrieve both seasonal and interannual dynamics in terms of the Purus river sediment discharge near its confluence with the Solimões River. Field radiometric and hydrologic measurements were acquired during 18 sampling trips, including 115 surface water samples and 61 river discharge measurements. Remote sensing reflectance gave important results in the red and infrared levels. They were very well correlated with suspended sediment concentration. The values of R2 are greater than 0.8 (red band) and 0.9 (NIR band). A retrieval algorithm based on the reflectance in both the red and the infrared was calibrated using the water samples collected for the determination of the surface-suspended sediment concentration (SSS). The algorithm was used to calculate 16 years of SSS time series with MODIS images at the Purus River near its confluence with the Solimões River. Results from satellite data correlated with in situ SSS values validate the use of satellite data to be used as a tool to monitor SSS in the Purus River. We evidenced a very short and intense sediment discharge pulse with 55% of the annual sediment budget discharged during the months of January and February. Using river discharge records, we calculated the mean annual sediment discharge of the Purus River at about of 17 Mt·yr-1.

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

NASA Astrophysics Data System (ADS)

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

2014-12-01

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

Suspended sediment load below open-cast mines for ungauged river basin

NASA Astrophysics Data System (ADS)

Kuksina, L.

2011-12-01

Placer mines are located in river valleys along river benches or river ancient channels. Frequently the existing mining sites are characterized by low contribution of the environmental technologies. Therefore open-pit mining alters stream hydrology and sediment processes and enhances sediment transport. The most serious environmental consequences of the sediment yield increase occur in the rivers populated by salmon fish community because salmon species prefer clean water with low turbidity. For instance, placer mining located in Kamchatka peninsula (Far East of Russia) which is regarded to be the last global gene pool of wild salmon Oncorhynchus threatens rivers ecosystems significantly. Impact assessment is limited by the hydrological observations scarcity. Gauging network is rare and in many cases whole basins up to 200 km length miss any hydrological data. The main purpose of the work is elaboration of methods for sediment yield estimation in rivers under mining impact and implementation of corresponding calculations. Subjects of the study are rivers of the Vivenka river basin where open-cast platinum mine is situated. It's one of the largest platinum mines in Russian Federation and in the world. This mine is the most well-studied in Kamchatka (research covers a period from 2003 to 2011). Empirical - analytical model of suspended sediment yield estimation was elaborated for rivers draining mine's territories. Sediment delivery at the open-cast mine happens due to the following sediment processes: - erosion in the channel diversions; - soil erosion on the exposed hillsides; - effluent from settling ponds; - mine waste water inflow; - accident mine waste water escape into rivers. Sediment washout caused by erosion was estimated by repeated measurements of the channel profiles in 2003, 2006 and 2008. Estimation of horizontal deformation rates was carried out on the basis of erosion dependence on water discharge rates, slopes and composition of sediments. Soil erosion on the exposed hillsides was estimated taking into account precipitation of various intensity and solid material washout during this period. Effluent from settling ponds was calculated on the basis of minimum anthropogenic turbidity. Its value is difference in background turbidity and minimal turbidity caused by effluent and waste water overflow. Mine waste water inflow was estimated due to actual data on water balance of purification system. Accident mine waste water escape into rivers was estimated by duration and material washout during accidents data measured during observation period. Total suspended sediment yield of rivers draining mine's territory is the sum of its components. Total sediment supply from mining site is 24.7 % from the Vivenka sediment yield. Polluted placer-mined rivers contribute about 35.4 % of the whole sediment yield of the Vivenka river. At the same time the catchment area of these rivers is less than 0.2 % from the whole Vivenka catchment area.

Effects of contaminants in dredge material from the Lower Savannah River

USGS Publications Warehouse

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

2000-01-01

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

PAHs and PCBs deposited in surficial sediments along a rural to urban transect in a mid-Atlantic coastal river basin (USA).

PubMed

Foster, Gregory D; Cui, Vickie

2008-10-01

PAHs and PCBs were measured in river sediments along a 226 km longitudinal transect that spanned rural to urban land use settings through Valley and Ridge, Piedmont Plateau and Coastal Plain physiographic provinces in the Potomac River basin (mid-Atlantic USA). A gradient in PAH concentrations was found in river bed sediments along the upstream transect in the Potomac and Shenandoah Rivers that correlated with population densities in the nearby sub-basins. Sediment PAH concentrations halved per each approximately 40 km of transect distance upstream (i.e., the half-concentration distance) from the urban center (Washington, DC) of the Potomac River basin in direct proportion to population density. The PAH molecular composition was consistent across all geologic provinces, revealing a dominant pyrogenic source. Fluoranthene to perylene ratios served as useful markers for urban inputs, with a ratio > 2.4 observed in sediments near urban structures such as roadways, bridges and sewer outfalls. PCBs in sediments were not well correlated with population densities along the river basin transect, but the highest concentrations were found in the urban Coastal Plain region near Washington, DC and in the Shenandoah River near a known industrial Superfund site. PAHs were moderately correlated with sediment total organic carbon (TOC) in the Shenandoah River and Coastal Plain Potomac River regions, but TOC was poorly correlated with PCB concentrations throughout the entire basin. Although both PAHs and PCBs are widely recognized as urban-derived contaminants, their concentration profiles and geochemistry in river sediments were uniquely different throughout the upper Potomac River basin.

Sediment characteristics in the San Antonio River Basin downstream from San Antonio, Texas, and at a site on the Guadalupe River downstream from the San Antonio River Basin, 1966-2013

USGS Publications Warehouse

Crow, Cassi L.; Banta, J. Ryan; Opsahl, Stephen P.

2014-01-01

San Antonio and surrounding municipalities in Bexar County, Texas, are in a rapidly urbanizing region in the San Antonio River Basin. The U.S. Geological Survey, in cooperation with the San Antonio River Authority and the Texas Water Development Board, compiled historical sediment data collected between 1996 and 2004 and collected suspended-sediment and bedload samples over a range of hydrologic conditions in the San Antonio River Basin downstream from San Antonio, Tex., and at a site on the Guadalupe River downstream from the San Antonio River Basin during 2011–13. In the suspended-sediment samples collected during 2011–13, an average of about 94 percent of the particles was less than 0.0625 millimeter (silt and clay sized particles); the 50 samples for which a complete sediment-size analysis was performed indicated that an average of about 69 percent of the particles was less than 0.002 millimeter. In the bedload samples collected during 2011–13, an average of 51 percent of sediment particles was sand-sized particles in the 0.25–0.5 millimeter-size range. In general, the loads calculated from the samples indicated that bedload typically composed less than 1 percent of the total sediment load. A least-squares log-linear regression was developed between suspended-sediment concentration and instantaneous streamflow and was used to estimate daily mean suspended-sediment loads based on daily mean streamflow. The daily mean suspended-sediment loads computed for each of the sites indicated that during 2011–12, the majority of the suspended-sediment loads originated upstream from the streamflow-gaging station on the San Antonio River near Elmendorf, Tex. A linear regression relation was developed between turbidity and suspended-sediment concentration data collected at the San Antonio River near Elmendorf site because the high-resolution data can facilitate understanding of the complex suspended-sediment dynamics over time and throughout the river basin.

Sediment regime constraints on river restoration - An example from the lower Missouri river

USGS Publications Warehouse

Jacobson, R.B.; Blevins, D.W.; Bitner, C.J.

2009-01-01

Dammed rivers are subject to changes in their flow, water-quality, and sediment regimes. Each of these changes may contribute to diminished aquatic habitat quality and quantity. Of the three factors, an altered sediment regime is a particularly unyielding challenge on many dammed rivers. The magnitude of the challenge is illustrated on the Lower Missouri River, where the largest water storage system in North America has decreased the downriver suspended-sediment load to 0.2%–17% of pre-dam loads. In response to the altered sediment regime, the Lower Missouri River channel has incised as much as 3.5 m just downstream of Gavins Point Dam, although the bed has been stable to slightly aggrading at other locations farther downstream. Effects of channel engineering and commercial dredging are superimposed on the broad-scale adjustments to the altered sediment regime.The altered sediment regime and geomorphic adjustments constrain restoration and management opportunities. Incision and aggradation limit some objectives of flow-regime management: In incising river segments, ecologically desirable reconnection of the floodplain requires discharges that are beyond operational limits, whereas in aggrading river segments, small spring pulses may inundate or saturate low-lying farmlands. Lack of sediment in the incising river segment downstream of Gavins Point Dam also limits sustainable restoration of sand-bar habitat for bird species listed under the Endangered Species Act. Creation of new shallow-water habitat for native fishes involves taking sediment out of floodplain storage and reintroducing most or all of it to the river, raising concerns about increased sediment, nutrient, and contaminant loads. Calculations indicate that effects of individual restoration projects are small relative to background loads, but cumulative effects may depend on sequence and locations of projects. An understanding of current and historical sediment fluxes, and how they vary along the river, provides a quantitative basis for defining management constraints and identifying opportunities.

Distribution characteristics of organochlorine pesticide in the water environment in Lanzhou section of Yellow River

NASA Astrophysics Data System (ADS)

Yang, L.; Zhao, X.; Shen, J. M.; Chen, Z. L.; Wang, X. C.; Qiu, H. R.

2017-04-01

Surface water, surface sediments and suspended particles in the Lanzhou section of Yellow River were collected. After the samples were lyophilised, extracted, concentrated, purified and separated, organochlorine pesticides in the samples were analysed by GC-MS. Results showed that organochlorine pesticide contents in surface water, surface sediments and suspended particles ranged from 28.63 ng/L to 123.2 ng/L, from 0.86 ng/g to 4.51 ng/g and from 23.29 ng/g to 126.14 ng/g, respectively. HCHs, DDTs and HCB were high; among these contents, HCH contents ranged from 1.49 ng/L to 18.1 ng/L, from 0.04ng/g to 1.53 ng/g and from 2.74ng/g to 25.64 ng/g, respectively. DDT contents ranged from 1.49 ng/Lto 18.1 ng/L, from 0.04 ng/g to 1.53 ng/g and from 2.74 ng/g to 25.64 ng/g, respectively. Component analysis results showed that organochlorine pesticide in the Lanzhou section of Yellow River was mainly from early residues or soil after pesticides were applied and long-term weathering occurred. Correlation analysis results showed that total organic carbon was an important factor affecting the distribution of organochlorine pesticide in sediments. Moderate organochlorine pesticide contents were detected in surface water in Lanzhou section of Yellow River compared with other rivers in our country and in other countries. Furthermore, the ecological risk of organochlorine pesticide in surface sediments was low.

Channel-conveyance capacity, channel change, and sediment transport in the lower Puyallup, White, and Carbon Rivers, western Washington

USGS Publications Warehouse

Czuba, Jonathan A.; Czuba, Christiana R.; Magirl, Chistopher S.; Voss, Frank D.

2010-01-01

Draining the volcanic, glaciated terrain of Mount Rainier, Washington, the Puyallup, White, and Carbon Rivers convey copious volumes of water and sediment down to Commencement Bay in Puget Sound. Recent flooding in the lowland river system has renewed interest in understanding sediment transport and its effects on flow conveyance throughout the lower drainage basin. Bathymetric and topographic data for 156 cross sections were surveyed in the lower Puyallup River system by the U.S. Geological Survey (USGS) and were compared with similar datasets collected in 1984. Regions of significant aggradation were measured along the Puyallup and White Rivers. Between 1984 and 2009, aggradation totals as measured by changes in average channel elevation were as much as 7.5, 6.5, and 2 feet on the Puyallup, White, and Carbon Rivers, respectively. These aggrading river sections correlated with decreasing slopes in riverbeds where the rivers exit relatively confined sections in the upper drainage and enter the relatively unconstricted valleys of the low-gradient Puget Lowland. Measured grain-size distributions from each riverbed showed a progressive fining downstream. Analysis of stage-discharge relations at streamflow-gaging stations along rivers draining Mount Rainier demonstrated the dynamic nature of channel morphology on river courses influenced by glaciated, volcanic terrain. The greatest rates of aggradation since the 1980s were in the Nisqually River near National (5.0 inches per year) and the White River near Auburn (1.8 inches per year). Less pronounced aggradation was measured on the Puyallup River and the White River just downstream of Mud Mountain Dam. The largest measured rate of incision was measured in the Cowlitz River at Packwood (5.0 inches per year). Channel-conveyance capacity estimated using a one-dimensional hydraulic model decreased in some river reaches since 1984. The reach exhibiting the largest decrease (about 20-50 percent) in channel-conveyance capacity was the White River between R Street Bridge and the Lake Tapps return, a reach affected by recent flooding. Conveyance capacity also decreased in sections of the Puyallup River. Conveyance capacity was mostly unchanged along other study reaches. Bedload transport was simulated throughout the entire river network and consistent with other observations and analyses, the hydraulic model showed that the upper Puyallup and White Rivers tended to accumulate sediment. Accuracy of the bedload-transport modeling, however, was limited due to a scarcity of sediment-transport data sets from the Puyallup system, mantling of sand over cobbles in the lower Puyallup and White Rivers, and overall uncertainty in modeling sediment transport in gravel-bedded rivers. Consequently, the output results from the model were treated as more qualitative in value, useful in comparing geomorphic trends within different river reaches, but not accurate in producing precise predictions of mass of sediment moved or deposited. The hydraulic model and the bedload-transport component were useful for analyzing proposed river-management options, if surveyed cross sections adequately represented the river-management site and proposed management options. The hydraulic model showed that setback levees would provide greater flood protection than gravel-bar scalping after the initial project construction and for some time thereafter, although the model was not accurate enough to quantify the length of time of the flood protection. The greatest hydraulic benefit from setback levees would be a substantial increase in the effective channel-conveyance area. By widening the distance between levees, the new floodplain would accommodate larger increases in discharge with relatively small incremental increases in stage. Model simulation results indicate that the hydraulic benefit from a setback levee also would be long-lived and would effectively compensate for increased deposition within the setback reach

Post-accidental riverine dispersion of sediments contaminated by radionuclides: confrontation of lessons learnt from Chernobyl and Fukushima case studies in catchments from Russia (1986-2009) and Japan (2011-2012)

NASA Astrophysics Data System (ADS)

Evrard, Olivier; Belyaev, Vladimir; Onda, Yuichi; Chartin, Caroline; Patin, Jeremy; Lefèvre, Irène; Ayrault, Sophie; Ivanova, Nadezda; Bonté, Philippe; Golosov, Valentin

2013-04-01

Chernobyl (1986) and Fukushima (2011) nuclear power plant accidents led to the release of important quantities of radionuclides (e.g., Cs-134; Cs-137) into the environment, and to the formation of severe contamination plumes (with initial Cs-137 activities exceeding typically 400 kBq m-2) on soils of the regions exposed to the radioactive fallout. This leads to important consequences for agriculture in strongly contaminated areas where the most affected fields should not be cultivated anymore during long periods of time, depending on the half life of the emitted radionuclides. Furthermore, sediment transfer in rivers can lead to the dispersion of radioactive contamination into larger areas over time. In this paper, we propose a methodology to trace and model radioactive contamination in river catchments over the short (2 yrs) and the longer term (25 yr) after major nuclear power plant accidents. This methodology is established and confronted to two case studies. The most recent study was conducted in the coastal catchments of the Rivers Nitta, Mano and Ota (ca. 600 km²) draining the main part of the radioactive pollution plume that deposited across Fukushima Prefecture. Three field campaigns were conducted to sample riverbed sediment along those rivers after the summer typhoons and the spring snowmelt (i.e., in Nov 2011, April 2012 and Nov 2012). Based on their analysis in gamma spectrometry, we show the rapid dispersion of the inland contamination and its progressive export by coastal rivers to the Pacific Ocean. This is confirmed by measurements of the Ag-110m: Cs-137 ratio. Analysis of sediment sequences that accumulated in reservoirs of the region provides additional information on the magnitude on sediment transfers in those areas. This rapid dispersion of radioactive contamination in Japan is confronted to lessons learnt from a case study conducted in the Plava River catchment (ca. 2000 km²) located in the so-called "Plavsk contamination hotspot", in western Russia. We used the Landsoil expert-based erosion model, 137Cs inventory profiles and alluvial sediment core analyses to understand and quantify contaminated sediment transfer across the cultivated catchment since 1986. Our results show that soil redistribution in the fields was dominant, and that sediment eroded from cropland mostly re-deposited in dry valleys during the heaviest storms. Overall, only 15 to 25% of material eroded from the hillslopes was delivered to the river valleys. Accumulation of contaminated sediment in dry valley systems therefore constitutes a major problem 25 years after Chernobyl accident. In conclusion, we show how the experience acquired after the Chernobyl accident contributed to facilitate the urgent analysis of sediment transfers across Fukushima Prefecture, where the possible measurement of relatively short-lived radionuclides (Ag-110m, Cs-134) provided a way to conduct a rapid quantitative assessment of contaminated sediment sources and exports.

Impacts of large dams on the complexity of suspended sediment dynamics in the Yangtze River

NASA Astrophysics Data System (ADS)

Wang, Yuankun; Rhoads, Bruce L.; Wang, Dong; Wu, Jichun; Zhang, Xiao

2018-03-01

The Yangtze River is one of the largest and most important rivers in the world. Over the past several decades, the natural sediment regime of the Yangtze River has been altered by the construction of dams. This paper uses multi-scale entropy analysis to ascertain the impacts of large dams on the complexity of high-frequency suspended sediment dynamics in the Yangtze River system, especially after impoundment of the Three Gorges Dam (TGD). In this study, the complexity of sediment dynamics is quantified by framing it within the context of entropy analysis of time series. Data on daily sediment loads for four stations located in the mainstem are analyzed for the past 60 years. The results indicate that dam construction has reduced the complexity of short-term (1-30 days) variation in sediment dynamics near the structures, but that complexity has actually increased farther downstream. This spatial pattern seems to reflect a filtering effect of the dams on the on the temporal pattern of sediment loads as well as decreased longitudinal connectivity of sediment transfer through the river system, resulting in downstream enhancement of the influence of local sediment inputs by tributaries on sediment dynamics. The TGD has had a substantial impact on the complexity of sediment series in the mainstem of the Yangtze River, especially after it became fully operational. This enhanced impact is attributed to the high trapping efficiency of this dam and its associated large reservoir. The sediment dynamics "signal" becomes more spatially variable after dam construction. This study demonstrates the spatial influence of dams on the high-frequency temporal complexity of sediment regimes and provides valuable information that can be used to guide environmental conservation of the Yangtze River.

Sediment matrix characterization as a tool for evaluating the environmental impact of heavy metals in metal mining, smelting, and ore processing areas.

PubMed

Ružičková, Silvia; Remeteiová, Dagmar; Mičková, Vladislava; Dirner, Vojtech

2018-02-21

In this work, the matrix characterization (mineralogy, total and local chemical composition, and total organic (TOC) and inorganic carbon (TIC) contents) of different types of sediments from mining- and metallurgy-influenced areas and the assessment of the impact of the matrix on the association of potentially hazardous metals with the mineral phases of these samples, which affect their mobility in the environment, are presented. For these purposes, sediment samples with different origins and from different locations in the environment were analyzed. Anthropogenic sediments from metal-rich post-flotation tailings (Lintich, Slovakia) represent waste from ore processing, natural river sediments from the Hornád River (Košice, Slovakia) represent areas influenced predominantly by the metallurgical industry, and lake sediments from a water reservoir Ružín (inflow from the Hornád and Hnilec Rivers, Slovakia) represent the impact of the metallurgical and/or mining industries. The total metal contents were determined by X-ray fluorescence (XRF) analysis, the local chemical and morphological microanalysis by scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), and the TOC and TIC contents by infrared (IR) spectrometry. The mobility/bioavailability of Cu, Pb, and Zn in/from sediments at the studied areas was assessed by ethylenediaminetetraacetic acid (EDTA) and acetic acid (AA) extraction and is discussed in the context of the matrix composition. The contents of selected potentially hazardous elements in the extracts were determined by the high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS).

Change in Sediment Provenance Near the Current Estuary of Yellow River Since the Holocene Transgression

NASA Astrophysics Data System (ADS)

Song, Sheng; Feng, Xiuli; Li, Guogang; Liu, Xiao; Xiao, Xiao; Feng, Li

2018-06-01

Sedimentary sequence and sediment provenance are important factors when it comes to the studies on marine sedimentation. This paper studies grain size distribution, lithological characteristics, major and rare earth elemental compositions, micropaleontological features and 14C ages in order to examine sedimentary sequence and sediment provenance of the core BH6 drilled at the mouth of the Yellow River in Bohai Sea. According to the grain size and the micropaleontological compositions, 4 sedimentary units have been identified. Unit 1 (0-8.08 mbsf) is of the delta sedimentary facies, Unit 2 (8.08-12.08 mbsf) is of the neritic shelf facies, Unit 3 (12.08-23.85 mbsf) is of near-estuary beach-tidal facies, and Unit 4 (23.85 mbsf-) is of the continental lake facies. The deposits from Unit 1 to Unit 3 have been found to be marine strata formed after the Holocene transgression at about 10 ka BP, while Unit 4 is continental lacustrine deposit formed before 10 ka BP. The provenances of core BH6 sediments show properties of the continental crust and vary in different sedimentary periods. For Unit 4 sediments, the source regions are dispersed while the main provenance is not clear, although the parent rock characteristics of a few samples are similar to the Luanhe River sediments. For Unit 3, sediments at 21.1-23.85 mbsf have been mainly transported from the Liaohe River, while sediments above 21.1 mbsf are mainly from the Yellow River and partially from the Liaohe River. For Unit 2, the sediments have been mainly transported from the Yellow River, with a small amount from other rivers. For Unit 1, the provenance is mainly the Yellow River catchment. These results help in better understanding the evolution of the Yellow River Delta.

Sediment yield during typhoon events in relation to landslides, rainfall, and catchment areas in Taiwan

NASA Astrophysics Data System (ADS)

Chen, Chi-Wen; Oguchi, Takashi; Hayakawa, Yuichi S.; Saito, Hitoshi; Chen, Hongey; Lin, Guan-Wei; Wei, Lun-Wei; Chao, Yi-Chiung

2018-02-01

Debris sourced from landslides will result in environmental problems such as increased sediment discharge in rivers. This study analyzed the sediment discharge of 17 main rivers in Taiwan during 14 typhoon events, selected from the catchment area and river length, that caused landslides according to government reports. The measured suspended sediment and water discharge, collected from hydrometric stations of the Water Resources Agency of Taiwan, were used to establish rating-curve relationships, a power-law relation between them. Then sediment discharge during typhoon events was estimated using the rating-curve method and the measured data of daily water discharge. Positive correlations between sediment discharge and rainfall conditions for each river indicate that sediment discharge increases when a greater amount of rainfall or a higher intensity of rainfall falls during a typhoon event. In addition, the amount of sediment discharge during a typhoon event is mainly controlled by the total amount of rainfall, not by peak rainfall. Differences in correlation equations among the rivers suggest that catchments with larger areas produce more sediment. Catchments with relatively low sediment discharge show more distinct increases in sediment discharge in response to increases in rainfall, owing to the little opportunity for deposition in small catchments with high connectivity to rivers and the transportation of the majority of landslide debris to rivers during typhoon events. Also, differences in geomorphic and geologic conditions among catchments around Taiwan lead to a variety of suspended sediment dynamics and the sediment budget. Positive correlation between average sediment discharge and average area of landslides during typhoon events indicates that when larger landslides are caused by heavier rainfall during a typhoon event, more loose materials from the most recent landslide debris are flushed into rivers, resulting in higher sediment discharge. The high proportion of large landslides in Taiwan contributes significantly to the high annual sediment yield, which is among the world's highest despite the small area of Taiwan.

Control of Sediment Availability on the Path of Channel Recovery in Bedload-Dominated Rivers

NASA Astrophysics Data System (ADS)

Doyle, H.; Renshaw, C. E.; Magilligan, F. J.

2015-12-01

Following a disturbance, a channel can recover to an equilibrium form by adjusting its slope, width, depth, grain size, or some combination of these dimensions that define the recovery path. In this study we relate the channel recovery path to the quantity and caliber of sediment introduced due to dam construction/removal or erosion caused by flooding. We suggest that the recovery path of a channel depends on the availability of sediment of a size that is transported as bedload during bankfull flows (the "mobile fraction"). We define a ratio, S*, of the sediment volume added to the channel because of the disturbance to the average annual sediment flux. We compare S* values to the recovery path of New England gravel-bedded streams following two dam emplacements and removals and flooding related to Tropical Storm Irene. Pelham Dam in Pelham, MA (removed 2012) and Kendrick Dam in Pittsford, VT (removed 2014) were on similar streams: drainage areas ~25 km2, slopes 1-2%, and bankfull widths ~10 m. Sediment was excavated from both impoundments prior to removal, resulting in lower S* values. Irene-affected study sites are on ~10 gravel-bedded streams in VT, NH, and MA. Sediment input at these sites is due to bank failures and landslides, many of which continue to supply sediment to the channel four years after flooding. To track recovery we collected annual topographic and sediment size data and calculated Shields numbers to determine if channels had reached an equilibrium form. We define equilibrium for bedload rivers as Shields numbers at bankfull discharge equal to that required to initiate bedload transport. Following dam emplacements the channels failed to recover because mobile sediment was unavailable. Fining dominated the recovery at Irene-affected sites (~10% reduction in sediment size) and dam removal sites (up to 30-60% reduction) with little post-disturbance change in channel geometry, possibly due to the limited mobile fraction.

Responses of benthic bacteria to experimental drying in sediments from Mediterranean temporary rivers.

PubMed

Amalfitano, Stefano; Fazi, Stefano; Zoppini, Annamaria; Barra Caracciolo, Anna; Grenni, Paola; Puddu, Alberto

2008-02-01

In the semiarid Mediterranean regions, water scarcity represents a common physiological stress for microbial communities residing in river sediments. However, the effect of drying has not yet adequately been evaluated when analyzing riverine microbiological processes. The bacterial community structure (abundance, biomass, composition) and functioning (carbon production, live cell percentage) were assessed during experimental desiccation in microcosms with sediments from different Mediterranean temporary rivers (Tagliamento, Krathis, Mulargia, Pardiela). Our results showed that the overall responses to drying of the bacterial community were independent from sediment origin and strictly related to water content. During desiccation, a prompt decline (up to 100%) of the initial bacterial carbon production was followed by a slower decrease in abundance and biomass, with an overall reduction of 74% and 78%, respectively. By the end of the experiment, live cells were still abundant but depressed in their main metabolic functions, thus resulting in a drastic increase in the community turnover time. Only 14% of the initial live cell biomass was available in dry sediments to immediately start the reactivation of the aquatic microbial food web after the arrival of new water. Community composition analysis showed a relative increase in alpha- and beta-Proteobacteria, when passing from wet to dry conditions. Our results suggest that the occurrence of drought events could affect carbon cycling through the freshwater microbial compartment, by temporarily limiting microbial mineralization and altering bacterial community structure.

Coupling a basin erosion and river sediment transport model into a large scale hydrological model: an application in the Amazon basin

NASA Astrophysics Data System (ADS)

Buarque, D. C.; Collischonn, W.; Paiva, R. C. D.

2012-04-01

This study presents the first application and preliminary results of the large scale hydrodynamic/hydrological model MGB-IPH with a new module to predict the spatial distribution of the basin erosion and river sediment transport in a daily time step. The MGB-IPH is a large-scale, distributed and process based hydrological model that uses a catchment based discretization and the Hydrological Response Units (HRU) approach. It uses physical based equations to simulate the hydrological processes, such as the Penman Monteith model for evapotranspiration, and uses the Muskingum Cunge approach and a full 1D hydrodynamic model for river routing; including backwater effects and seasonal flooding. The sediment module of the MGB-IPH model is divided into two components: 1) prediction of erosion over the basin and sediment yield to river network; 2) sediment transport along the river channels. Both MGB-IPH and the sediment module use GIS tools to display relevant maps and to extract parameters from SRTM DEM (a 15" resolution was adopted). Using the catchment discretization the sediment module applies the Modified Universal Soil Loss Equation to predict soil loss from each HRU considering three sediment classes defined according to the soil texture: sand, silt and clay. The effects of topography on soil erosion are estimated by a two-dimensional slope length (LS) factor which using the contributing area approach and a local slope steepness (S), both estimated for each DEM pixel using GIS algorithms. The amount of sediment releasing to the catchment river reach in each day is calculated using a linear reservoir. Once the sediment reaches the river they are transported into the river channel using an advection equation for silt and clay and a sediment continuity equation for sand. A sediment balance based on the Yang sediment transport capacity, allowing to compute the amount of erosion and deposition along the rivers, is performed for sand particles as bed load, whilst no erosion or deposition is allowed for silt and clay. The model was first applied on the Madeira River basin, one of the major tributaries of the Amazon River (~1.4*106 km2) accounting for 35% of the suspended sediment amount annually transported for the Amazon river to the ocean. Model results agree with observed data, mainly for monthly and annual time scales. The spatial distribution of soil erosion within the basin showed a large amount of sediment being delivered from the Andean regions of Bolivia and Peru. Spatial distribution of mean annual sediment along the river showed that Madre de Dios, Mamoré and Beni rivers transport the major amount of sediment. Simulated daily suspended solid discharge agree with observed data. The model is able to provide temporaly and spatialy distributed estimates of soil loss source over the basin, locations with tendency for erosion or deposition along the rivers, and to reproduce long term sediment yield at several locations. Despite model results are encouraging, further effort is needed to validate the model considering the scarcity of data at large scale.

Dispersal of suspended sediments in the turbid and highly stratified Red River plume

NASA Astrophysics Data System (ADS)

van Maren, D. S.; Hoekstra, P.

2005-03-01

The Red River, annually transporting 100 million tons of sediment, flows into a shallow shelf sea where it rapidly deposits most of its sediment on a prograding delta front. Oceanographic cruises were carried out in February-March and July-August 2000 to determine the vertical structure of the Ba Lat river plume and sediment transport patterns on the delta front. The surface waters in the coastal zone were strongly stratified with a low density and high sediment concentration during the larger part of the wet season, caused by low mixing rates of river plumes with ambient water. The river plume is advected to the south by a well-developed coastal current which originates from the river plumes that enter the Gulf of Tonkin North of the Ba Lat and are deflected southward by the Coriolis force. Sediment predominantly leaves the surface plume by settling from suspension and less by mixing of fresh and marine water. A one-dimensional model for plume deposition valid for fair weather conditions indicates that most sediment is deposited within 10 km and southward of the river mouth. Of prime importance for this depositional pattern is the phase relation between river outflow and tidal currents, in combination with the southward surface flow; alongshore advection is very low during outflow of the turbid river plume. The agreement of modeled plume sedimentation patterns with long-term bathymetric changes strongly suggests that fair weather depositional processes determine delta front development. This may be related to the fact that reworking of sediment mainly occurs several months after the peak deposition period; in the meantime sediment compaction and consolidation have increased the shear strength of deposited sediments.

Human Influences on Geomorphic Dynamics in Western Montana Gravel-Bed Rivers

NASA Astrophysics Data System (ADS)

Wilcox, A. C.

2016-12-01

Management of river ecosystems, river restoration, climate-change vulnerability assessments, and other applications require understanding of how current channel conditions and processes compare to historical ranges of variability. This is particularly true with respect to evaluation of sediment balances, including of whether and how current sediment supply compares to background conditions. In western Montana, management and restoration efforts are in some cases driven by the perception that anthropogenic activities have elevated sediment yields above background levels; human-induced erosional increases have been documented in certain environments, but empirical supporting evidence is lacking for western Montana rivers. Here, human-induced changes in channel form and in sediment balances, including flow, sediment supply, and erosion rates, are evaluated for rivers in western Montana, with a particular focus on the Clark Fork and Bitterroot Rivers. These rivers are characteristic of systems in the northern Rocky Mountains with gravel beds, historically wandering channel patterns, modest bed-material loads, and land uses including logging, mining, and agriculture. The Clark Fork is influenced by legacy mining-related sediments and associated contaminants, remediation efforts, and the 2008 removal of Milltown Dam. These influences have caused temporary shifts in sediment balances, but overall, sediment fluxes are modest (e.g., suspended sediment fluxes of 6 tonnes km-2 yr-1 at the USGS Turah gage). The Bitterroot River is influenced by a mix of glaciated and unglaciated landscapes with fire-dominated erosional regimes and larger sand supply than the Clark Fork, reflecting lithologic differences; erosion rates, and the imprint of anthropogenic activities on sediment dynamics, are being investigated. This work has implications for river restoration, including whether measures are needed to impose channel stability, and for evaluating how climate-change-induced changes in fire, runoff, and erosion will alter fluvial sediment balances.

Reconnaissance of chemical and physical characteristics of selected bottom sediments of the Caloosahatchee River and estuary, tributaries, and contiguous bays, Lee County, Florida, July 20-30, 1998

USGS Publications Warehouse

Fernandez, Mario; Marot, M.E.; Holmes, C.W.

1999-01-01

This report summarizes a reconnaissance study, conducted July 20-30, 1998, of chemical and physical characteristics of recently deposited bottom sediments in the Caloosahatchee River and Estuary. Recently deposited sediments were identified using an isotopic chronometer, Beryllium-7 (7Be), a short-lived radioisotope. Fifty-nine sites were sampled in an area that encompasses the Caloosahatchee River (River) about three miles upstream from the Franklin Lock (S-79), the entire tidally affected length of the river (estuary), and the contiguous water bodies of Matlacha Pass, San Carlos Bay, Estero Bay, Tarpon Bay, and Pine Island Sound in Lee County, Florida. Bottom sediments were sampled for 7Be at 59 sites. From the results of the 7Be analysis, 30 sites were selected for physical and chemical analysis. Sediments were analyzed for particle size, total organic carbon (TOC), trace elements, and toxic organic compounds, using semiquantitative methods for trace elements and organic compounds. The semiquantitative scans of trace elements indicated that cadmium, copper, lead, and zinc concentrations, when normalized to aluminum, were above the natural background range at 24 of 30 sites. Particle size and TOC were used to characterize sediment deposition patterns and organic content. Pesticides, polychlorinated biphenyls (PCBs), and carcinogenic polycyclic aromatic hydrocarbons (CaPAHs) were determined at 30 sites using immunoassay analysis. The semiquantitative immunoassay analyses of toxic organic compounds indicated that all of the samples contained DDT, cyclodienes as chlordane (pesticides), and CaPAHs. PCBs were not detected. Based on analyses of the 30 sites, sediments at 10 of these sites were analyzed for selected trace elements and toxic organic compounds, including pesticides, PCBs, and PAHs, using quantitative laboratory procedures. No arsenic or cadmium was detected. Zinc was detected at two sites with concentrations greater than the lower limit of the range of sediment contaminant concentrations that are usually or always associated with adverse effects (Florida Department of Environmental Protection's Sediment Quality Assessment Guidelines). Organochlorine pesticides were detected at four sites at concentrations below the reporting limits; there were no organophosphorus pesticides or PCBs detected. PAHs were detected at eight sites; however, only four sites had concentrations above the reporting limit.

Spatial Patterns of Mercury Bioaccumulation in the Upper Clark Fork River Basin, MT

NASA Astrophysics Data System (ADS)

Staats, M. F.; Langner, H.; Moore, J. N.

2010-12-01

The Upper Clark Fork River Basin (UCFRB) in Montana has a legacy of historic gold/silver mine waste that contributes large quantities of mercury into the watershed. Mercury bioaccumulation at higher levels of the aquatic food chain, such as the mercury concentration in the blood of pre-fledge osprey, exhibit an irregular spatial signature based on the location of the nests throughout the river basin. Here we identify regions with a high concentration of bioavailable mercury and the major factors that allow the mercury to bioaccumulate within trophic levels. This identification is based on the abundance of mercury sources and the potential for mercury methylation. To address the source term, we did a survey of total mercury in fine sediments along selected UCFRB reaches, along with the assessment of environmental river conditions (percentage of backwaters/wetlands, water temperature and pH, etc). In addition, we analyzed the mercury levels of a representative number of macroinvertebrates and fish from key locations. The concentration of total mercury in sediment, which varies from reach to reach (tributaries of the Clark Fork River, <0.05 mg/kg to the main stem of the river, >5mg/kg) affects the concentration of mercury found at various trophic levels. However, reaches with a low supply of mine waste-derived mercury can also yield substantial concentrations of mercury in the biota, due to highly favorable conditions for mercury methylation. We identify that the major environmental factor that affects the methylation potential in the UCFRB is the proximity and connectivity of wetland areas to the river.

Environmental change in Yatsushiro tidal flat and the Kuma River (SW Kyushu, Japan) between 2002 and the present

NASA Astrophysics Data System (ADS)

Young, S. M.; Ishiga, H.

2012-12-01

The chemical compositions of sediments from Yatsushiro tidal flat, Kuma River, and Arase dam (south west Kyushu, Japan) have been determined to examine changes between 2002 and 2012. In 2002 sediment supply to the bay from the Kuma River was restricted by the Arase dam; however in 2010 the dam was opened, allowing resumption of natural sediment transport. Abundances of 24 elements in Yatsushiro tidal flat sediments (n=22), suspended solids in the bay (n=6), Kuma River stream sediments (n=5) and suspended solids (n=2) were determined by XRF. Ripple marks in the Yatsushiro tidal flat indicate inflow of coarser material from the reinvigorated river. Bulk chemical composition of the tidal flat sediments has changed since 2002, with marked decreases in As, Zn and total sulfur, and lesser and more variable decrease in Pb. Mn values are higher in the northern tidal flats, suggesting anoxic conditions in the sediments at those sites. Suspended solids in both the Kuma River and Yatsushiro Bay have very low values of heavy metals, indicating low absorption and dilution by high organic matter contents. Sediments behind the Arase dam in 2002 had high abundances of most of the elements analyzed. However, abundances in Kuma River stream sediments at similar locations have fallen since the dam was opened in 2010. Kuma River sediments are characteristically coarser than those in Yatsushiro Bay, except at three locations. The river sediments are relatively uniform in composition, with ranges of 72.27-75.35 wt% SiO2 and 12.09-14.01 wt% Al2O3, compared to 55.40-77.89 and 11.61-21.44 respectively for Yatsushiro Bay tidal flat sediments. Average values in both suites are similar to UCC. Decreased heavy metal contents in the bay sediments after opening of the dam is attributed to dilution by previously impounded quartz and feldspar. Restoration of natural sediment transport has thus bought about a favorable environmental change. Key words: Yatsushiro bay, Kuma River, Geochemistry, Tidal flat, Environmental change.

Geomorphic response to large-dam removal: Impacts of a massive sediment release to the Elwha River, Washington

NASA Astrophysics Data System (ADS)

Magirl, C. S.; Ritchie, A.; Bountry, J.; Randle, T. J.; East, A. E.; Hilldale, R. C.; Curran, C. A.; Pess, G. R.

2015-12-01

The 2011-2014 staged removals of two nearly century-old dams on the Elwha River in northwest Washington State, the largest dam-removal project in the United States, exposed 21 million m3 of reservoir-trapped sand and gravel to potential fluvial transport. The river downstream from the dams is gravel bedded with a pool-riffle morphology. The river flows 20 km to the marine environment through a riparian corridor lined with large wood and having relatively few anthropogenic alterations. This moderately natural pre-dam-removal condition afforded an unprecedented opportunity to study river response to an anticipated massive sediment release. Four years into the project, 12 million m3 of sediment eroded from the former reservoirs with about 90% of the total load transported to the marine environment. Annualized sediment discharge was as great as 20 times the background natural load. Initial river response to the arrival of the first large sediment pulse was the nearly complete filling of the river's previously sediment-starved pools, widespread filling of side channels, and increased braiding index. In year 2, during maximum aggradation, the river graded to a plane-bedded system, efficiently conveying sediment to the marine environment. Modest peak flows (<2-yr return period) in year 2 promoted sediment transport but caused little large-scale geomorphic disturbance by channel migration or avulsions. As the river processed the sediment pulse, pools returned and the braiding index decreased in years 3-4. Higher peak flows in year 4 caused localized channel widening and migration but no major avulsions. Gauging indicated sand dominated the first stages of sediment release, but fluvial loads coarsened through time with progressive arrival of larger material. The literature suggests the Elwha River sediment wave should have evolved through dispersion with little translation. However, morphologic measurements and data from a stage-gauge network indicated patterns of deposition, sediment transport, and sediment-wave evolution were heterogeneously complex, challenging our efforts to classify the sediment wave in terms of simple dispersion or translation.

Lower Charles River Bathymetry: 108 Years of Fresh Water

NASA Astrophysics Data System (ADS)

Yoder, M.; Sacarny, M.

2017-12-01

The Lower Charles River is a heavily utilized urban river that runs between Cambridge and Boston in Massachusetts. The recreational usage of the river is dependent on adequate water depths, but there have been no definitive prior studies on the sedimentation rate of the Lower Charles River. The river transitioned from tidal to a freshwater basin in 1908 due to the construction of the (old) Charles River Dam. Water surface height on the Lower Charles River is maintained within ±1 foot through controlled discharge at the new Charles River Dam. The current study area for historical comparisons is from the old Charles River Dam to the Boston University Bridge. This study conducted a bathymetric survey of the Lower Charles River, digitized three prior surveys in the study area, calculated volumes and depth distributions for each survey, and estimated sedimentation rates from fits to the volumes over time. The oldest chart digitized was produced in 1902 during dam construction deliberations. The average sedimentation rate is estimated as 5-10 mm/year, which implies 1.8-3.5 feet sedimentation since 1908. Sedimentation rates and distributions are necessary to develop comprehensive management plans for the river and there is evidence to suggest that sedimentation rates in the shallow upstream areas are higher than the inferred rates in the study area.

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

USGS Publications Warehouse

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

2010-01-01

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

The fate of large sediment inputs in rivers: Implications for watershed and waterway management

Treesearch

Thomas E. Lisle

2000-01-01

Valued resources in and along stream channels are commonly many river miles downstream of large sediment inputs such as landslides. Evaluating and predicting the arrival, severity, and duration of sediment impacts thus requires an understanding of how river channels digest elevated sediment loads.

An assessment of the suspended sediment rating curve approach for load estimation on the Rivers Bandon and Owenabue, Ireland

NASA Astrophysics Data System (ADS)

Harrington, Seán T.; Harrington, Joseph R.

2013-03-01

This paper presents an assessment of the suspended sediment rating curve approach for load estimation on the Rivers Bandon and Owenabue in Ireland. The rivers, located in the South of Ireland, are underlain by sandstone, limestones and mudstones, and the catchments are primarily agricultural. A comprehensive database of suspended sediment data is not available for rivers in Ireland. For such situations, it is common to estimate suspended sediment concentrations from the flow rate using the suspended sediment rating curve approach. These rating curves are most commonly constructed by applying linear regression to the logarithms of flow and suspended sediment concentration or by applying a power curve to normal data. Both methods are assessed in this paper for the Rivers Bandon and Owenabue. Turbidity-based suspended sediment loads are presented for each river based on continuous (15 min) flow data and the use of turbidity as a surrogate for suspended sediment concentration is investigated. A database of paired flow rate and suspended sediment concentration values, collected between the years 2004 and 2011, is used to generate rating curves for each river. From these, suspended sediment load estimates using the rating curve approach are estimated and compared to the turbidity based loads for each river. Loads are also estimated using stage and seasonally separated rating curves and daily flow data, for comparison purposes. The most accurate load estimate on the River Bandon is found using a stage separated power curve, while the most accurate load estimate on the River Owenabue is found using a general power curve. Maximum full monthly errors of - 76% to + 63% are found on the River Bandon with errors of - 65% to + 359% found on the River Owenabue. The average monthly error on the River Bandon is - 12% with an average error of + 87% on the River Owenabue. The use of daily flow data in the load estimation process does not result in a significant loss of accuracy on either river. Historic load estimates (with a 95% confidence interval) were hindcast from the flow record and average annual loads of 7253 ± 673 tonnes on the River Bandon and 1935 ± 325 tonnes on the River Owenabue were estimated to be passing the gauging stations.

[Effects of Long-term Implementation of the Flow-Sediment Regulation Scheme on Grain and Clay Compositions of Inshore Sediments in the Yellow River Estuary].

PubMed

Wang, Miao-miao; Sun, Zhi-gao; Lu, Xiao-ning; Wang, Wei; Wang, Chuan-yuan

2015-04-01

Based on the laser particle size and X-ray diffraction (XRD) analysis, 28 sediment samples collected from the inshore region of the Yellow River estuary in October 2013 were determined to discuss the influence of long-term implementation of the flow-sediment regulation scheme (FSRS, initiated in 2002) on the distributions of grain size and clay components (smectite, illite, kaolinite and chlorite) in sediments. Results showed that, after the FSRS was implemented for more than 10 years, although the proportion of sand in inshore sediments of the Yellow River estuary was higher (average value, 23.5%) than those in sediments of the Bohai Sea and the Yellow River, silt was predominated (average value, 59.1%) and clay components were relatively low (average value, 17.4%). The clay components in sediments of the inshore region in the Yellow River estuary were close with those in the Yellow River. The situation was greatly changed due to the implementation of FSRS since 2002, and the clay components were in the order of illite > smectite > chlorite > kaolinite. This study also indicated that, compared to large-scale investigation in Bohai Sea, the local study on the inshore region of the Yellow River estuary was more favorable for revealing the effects of long-term implementation of the FSRS on sedimentation environment of the Yellow River estuary.

Mount Baker lahars and debris flows, ancient, modern, and future

USGS Publications Warehouse

Tucker, David S; Scott, Kevin M.; Grossman, Eric E.; Linneman, Scott

2014-01-01

Holocene lahars and large debris flows (>106 m3) have left recognizable deposits in the Middle Fork Nooksack valley. A debris flow in 2013 resulting from a landslide in a Little Ice Age moraine had an estimated volume of 100,000 m3, yet affected turbidity for the entire length of the river, and produced a slug of sediment that is currently being reworked and remobilized in the river system. Deposits of smaller-volume debris flows, deposited as terraces in the upper valley, may be entirely eroded within a few years. Consequently, the geologic record of small debris flows such as those that occurred in 2013 is probably very fragmentary. Small debris flows may still have significant impacts on hydrology, biology, and human uses of rivers downstream. Impacts include the addition of waves of fine sediment to stream loads, scouring or burying salmon-spawning gravels, forcing unplanned and sudden closure of municipal water intakes, damaging or destroying trail crossings, extending river deltas into estuaries, and adding to silting of harbors near river mouths.

Developing a GIS based integrated approach to flood management in Trinidad, West Indies.

PubMed

Ramlal, Bheshem; Baban, Serwan M J

2008-09-01

Trinidad and Tobago is plagued with a perennial flooding problem. The higher levels of rainfall in the wet season often lead to extensive flooding in the low-lying areas of the country. This has lead to significant damage to livestock, agricultural produce, homes and businesses particularly in the Caparo River Basin. Clearly, there is a need for developing flood mitigation and management strategies to manage flooding in the areas most affected. This paper utilizes geographic information systems to map the extent of the flooding, estimate soil loss due to erosion and estimate sediment loading in the rivers in the Caparo River Basin. In addition, the project required the development of a watershed management plan and a flood control plan. The results indicate that flooding was caused by several factors including clear cutting of vegetative cover, especially in areas of steep slopes that lead to sediment filled rivers and narrow waterways. Other factors include poor agricultural practices, and uncontrolled development in floodplains. Recommendations to manage floods in the Caparo River Basin have been provided.

PROFILE: Hungry Water: Effects of Dams and Gravel Mining on River Channels

PubMed

Kondolf

1997-07-01

/ Rivers transport sediment from eroding uplands to depositional areas near sea level. If the continuity of sediment transport is interrupted by dams or removal of sediment from the channel by gravel mining, the flow may become sediment-starved (hungry water) and prone to erode the channel bed and banks, producing channel incision (downcutting), coarsening of bed material, and loss of spawning gravels for salmon and trout (as smaller gravels are transported without replacement from upstream). Gravel is artificially added to the River Rhine to prevent further incision and to many other rivers in attempts to restore spawning habitat. It is possible to pass incoming sediment through some small reservoirs, thereby maintaining the continuity of sediment transport through the system. Damming and mining have reduced sediment delivery from rivers to many coastal areas, leading to accelerated beach erosion. Sand and gravel are mined for construction aggregate from river channel and floodplains. In-channel mining commonly causes incision, which may propagate up- and downstream of the mine, undermining bridges, inducing channel instability, and lowering alluvial water tables. Floodplain gravel pits have the potential to become wildlife habitat upon reclamation, but may be captured by the active channel and thereby become instream pits. Management of sand and gravel in rivers must be done on a regional basis, restoring the continuity of sediment transport where possible and encouraging alternatives to river-derived aggregate sources.KEY WORDS: Dams; Aquatic habitat; Sediment transport; Erosion; Sedimentation; Gravel mining

Sediment and water discharge rates of Turkish Black Sea rivers before and after hydropower dam construction

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

Hay, B.J.

1994-06-01

Presently, the water discharge rate to the Black Sea by Turkish rivers is approximately 41 km[sup 3]/yr. The sediment discharge rate of Turkish rivers to the Black Sea is 28 x 10[sup 6] t/yr. Before construction of the hydroelectric dams, the sediment discharge rate was approximately 70 x 10[sup 6] t/yr. The sharp reduction in sediment load is largely a result of the dams near the mouths of the Yesil Irmak and Kizil Irmak rivers. Before the construction of dams, Turkish rivers contributed approximately one third of the total amount of sediment received by the Black Sea from all surroundingmore » rivers. The life-span of the major reservoirs varies from approximately only one century (Yesil Irmak river reservoirs) to several thousand years (Sakarya river reservoirs). Life-span for the large Altinkaya Dam reservoir is estimated with approximately 500 yr.« less

Changes of floodplain morphology by water mills: Legacy sediments stored behind mill dams as archive and source for pollution - Examples from the Wurm River, Lower Rhine Embayment, Germany

NASA Astrophysics Data System (ADS)

Buchty-Lemke, Michael; Frings, Roy; Hagemann, Lukas; Lehmkuhl, Frank; Maaß, Anna-Lisa; Schwarzbauer, Jan

2016-04-01

The Wurm River (Lower Rhine Embayment, Germany) is a small stream in a low mountain area near the Dutch-German border that has seen a lot of anthropogenic changes of its morphology since medieval times. Among other influencing factors, water mills, in particular, had an early impact on the sediment dynamics and created sediment traps. Several knickpoints in the long profile may represent the legacy of mill damming - or founded mill building at these spots. The knickpoints may also represent the aftermath of the colliery history. A study site in the upper reaches of the Wurm River features erosion terraces, incised following the demise of a mill dam in the early 20th century. The mill pond most likely collected sediment and additives e.g. used in agricultural and industrial processes. These legacy sediments from behind former mill dams provide information about anthropogenic pollution, particularly for the era of industrialization in the vicinity of the old industrial area of the city of Aachen. Along with the demise of the mill dam and the increased incision tendency, the sediments are also a secondary source for pollution in case of remobilization of contaminated sediments. Two major research questions are addressed. A) Which individual hydrological and geomorphological processes, both upstream and downstream, triggered the incision and the construction of the erosion terraces, which are preserved in the mill pond sediments? Is either the demised mill dam, or subsidence effects, or a combination of both the determining factor? B) Which contaminants are retained in the sediments? Is there a detectable point source for the pollutants or is it a mixture of diffuse anthropogenic (industry, agriculture, traffic, wastewater) and natural origin? To tackle these questions, sedimentological data are combined with geomorphological mapping and evaluation of historical data. A soil profile provides insight into the architecture of the floodplain, which is built of riverbed sediments overlain by stratified fine clastic and organic-rich material, representing the sediment being trapped when the mill dam existed. X-ray fluorescence and grain size analysis are used to determine the depositional process, provenance and chemostratigraphy. Knowledge about the distribution and fate of pollutants in sediments is valuable for river management purposes. Measures within the scope of the EU Water Framework Directive have been implemented at several breaches at the Wurm River, and further ones are planned. Potential risks due to remobilization of polluted alluvial sediments must thereby be taken into account. Furthermore, e.g. dismantling of transverse structures to improve passage for fish might trigger similar erosion processes and affects the sediment continuity.

Sediment budget analysis from Landslide debris and river channel change during the extreme event - example of Typhoon Morakot at Laonong river, Taiwan

NASA Astrophysics Data System (ADS)

Chang, Kuo-Jen; Huang, Yu-Ting; Huang, Mei-Jen; Chiang, Yi-Lin; Yeh, En-Chao; Chao, Yu-Jui

2014-05-01

Taiwan, due to the high seismicity and high annual rainfall, numerous landslides triggered every year and severe impacts affect the island. Typhoon Morakot brought extreme and long-time rainfall for Taiwan in August 2009. It further caused huge loss of life and property in central and southern Taiwan. Laonong River is the largest tributary of Gaoping River. It's length is 137 km, and the basin area is 1373 km2. More than 2000mm rainfall brought and maximum rainfall exceeded 100mm/hr in the region by Typhoon Morakot in Aug, 2009. Its heavy rains made many landslides and debris flew into the river and further brought out accumulation and erosion on river banks of different areas. It caused severe disasters within the Laonong River drainage. In the past, the study of sediment blockage of river channel usually relies on field investigation, but due to inconvenient transportation, topographical barriers, or located in remote areas, etc. the survey is hardly to be completed sometimes. In recent years, the rapid development of remote sensing technology improves image resolution and quality significantly. Remote sensing technology can provide a wide range of image data, and provide essential and precious information. Furthermore, although the amount of sediment transportation can be estimated by using data such as rainfall, river flux, and suspended loads, the situation of large debris migration cannot be studied via those data. However, landslides, debris flow and river sediment transportation model in catchment area can be evaluated easily through analyzing the digital terrain model (DTM) . The purpose of this study is to investigate the phenomenon of river migration and to evaluate the amount of migration along Laonong River by analyzing the DEM before and after the typhoon Morakot. The DEMs are built by using the aerial images taken by digital mapping camera (DMC) and by airborne digital scanner 40 (ADS 40) before and after typhoon event. The results show that lateral erosion of the Laonong River caused by the typhoon seriously, especially in Yushan National Park, and midstream region. However, lateral erosion in downstream region is not so obvious. Meanwhile the siltation depth resulted from the Typhoon Morakot is larger in upstream region than in midstream and downstream regions. The amount of landslide debris created by Typhoon Morakot was too excessive to be transported. Materials just siltated in the upstream in place, same as in the middle stream area. Because of the amount of river slope erosion and sediment collapse in the downstream region is less than in upstream and midstream region, the amount of river erosion slightly larger than the amount of river siltation. The goals of this project are trying to decipher the sliding process and morphologic changes of large landslide areas, sediment transport and budgets, and to investigate the phenomenon of river migration. The results of this study provides not only geomatics and GIS dataset of the hazards, but also for essential geomorphologic information for other study, and for hazard mitigation and planning, as well.

Characterisation of organic matter source and sediment distribution in Ashtamudi Estuary, southern India

NASA Astrophysics Data System (ADS)

Kumar, Prem; Ankit, Yadav; Mishra, Praveen K.; Jha, Deepak Kumar; Anoop, Ambili

2017-04-01

In the present study we have focussed on the surface sediments of Ashtamudi Estuary (southern India) to understand (i) the fate and sources of organic matter by investigating lipid biomarker (n-alkanes) distribution in modern sediments and vegetation samples and (ii) the processes controlling the sediment distribution into the lake basin using end-member modelling approach. The sediment n-alkanes from the Ashtamudi Estuary exhibit a pronounced odd over even predominance with maxima at C29 and C31 chain length indicative of a dominant terrestrial contribution. A number of n-alkane indices have been calculated to illustrate the variability in space by considering separately the river dominated northern reaches and tidal influenced southern part of Ashtamudi Estuary. The highest terrigenous organic contents were found in sediments from the river and upper bay sites, with smaller contributions to the lower parts of the estuary. The Paq and TAR (terrigenous/aquatic ratio) indices demonstrate maximum aquatic productivity (plankton growth and submerged macrophytes) in the tidal dominated region of the Ashtamudi Estuary. The carbon preference index (CPI) and average chain length (ACL) provide evidence for high petrogenic organic inputs in the tidal zone, whereas dominant biogenic contribution have been observed in the riverine zone. In addition, the end member modeling of the grain size distribution of the surface sediment samples enabled us to decipher significant sedimentological processes affecting the sediment distribution in the estuarine settings. The end-member distribution showing highest loading with the coarser fraction is maximum where estuary debouches into the sea. However, the samples near the mouth of the river shows finer fraction of the end-member.

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

USGS Publications Warehouse

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

2000-01-01

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.

Role of ISM circulations in Western Kachchh, India during Mid-Late Holocene in disarticulation of Human Settlements

NASA Astrophysics Data System (ADS)

Dabhi, M.

2017-12-01

Paleoclimatic record indicates that one of the major factors for change in Indian Summer Monsoon (ISM) is North Atlantic Oceanic Circulation (NAO). Climatic changes have often been an influential factor in culture developments and dislocation of human settlements. The climatic transformations in Western India are affected by variation in the Indian Summer Monsoon (ISM). During last millennial scale, Indian sub-continent has observed varied climatic oscillations due to temperature variations in ocean and continent. People and society are the most affected lot due to this climate and monsoonal changes, which finally leads towards migration or colonization of people. Therefore, a high resolution data is required to delineate the complexity of monsoonal variation. This study focuses on the Mid-Late Holocene monsoonal changes from the sediment record of Western Kachchh. The field of study is at the mount of Kali River, a 45 km long river originating from the hills of Western Mainland Kachchh and debouching into Kori Creek. The exposed cross-section along the river bank has a fluvial unit (Unit-1) at the base followed by human settlement marked as Unit-2 culminating with eolian deposits (Unit-3) at the top. Multiproxy analysis (sedimentologically, optically and geochemically) were carried out to ascertain the climatic perturbations in the region. The lower Unit 1 which range in age from 6-5 Ka shows declining monsoon. The above exposed sediments with anthropogenic activity (Unit 2) cover a time span of 3-2.5 ka indicates monsoonal stability with declining trends. The general weakening of monsoon may be a major factor towards the ending or migration of the human settlement leading to the absence of archeological activity above 2.5ka in the area. The eolian sediments resting above the Unit 2 fall between 450 to 230 yrs represent the trends of Little Ice Age. Sediment record from the opposite bank of the river reveals an age of 1100 yrs supports wet condition which is co-relatable with the global Medieval Warm Period (MWP). Based on detail study it can be interpreted that the area has been highly affected by Indian Summer Monsoon variability since last 5ka and early historic human occupation that has been affected by the climatic transformations.

Effects of flushing Spencer Hydro on water quality, fish, and insect fauna in the Niobrara River, Nebraska

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

Hesse, L.W.; Newcomb, B.A.

Hydroelectric facilities with a low generating capacity (approximately one megawatt) such as Spencer Hydro on the Niobrara River in Nebraska are important, as referenced by the renewed interest in the revival of many that were deactivated with the advent of large fossil fuel and nuclear generating stations. The water reservoir impounded by the Spencer Dam is shallow and entrapped sediment quickly fills the pond, reducing power generating potential and threatening the internal components of the hydro station. This action requires periodic flushings to allow settled sediment to move past the station, resulting in adverse impacts on water quality, fish, andmore » fish-food organisms in the 63.3 km of Niobrara River downstream from the dam. Investigations in 1979 revealed unacceptable low levels of DO (3.5-4.0 mg/liter), pronounced increases in turbidity (>400%) and suspended solids (4-fold), and a doubling of dissolved solids. Thirty species of fish were affected, with a conservative count of 22,471 dead fish plus others under extreme stress. Young fish were most affected. There also were large changes in the abundance of many species of immature aquatic insects. A series of corrective recommendations are proposed to alleviate the problem and enhance the fishery in the lower river.« less

Linking rapid erosion of the Mekong River delta to human activities.

PubMed

Anthony, Edward J; Brunier, Guillaume; Besset, Manon; Goichot, Marc; Dussouillez, Philippe; Nguyen, Van Lap

2015-10-08

As international concern for the survival of deltas grows, the Mekong River delta, the world's third largest delta, densely populated, considered as Southeast Asia's most important food basket, and rich in biodiversity at the world scale, is also increasingly affected by human activities and exposed to subsidence and coastal erosion. Several dams have been constructed upstream of the delta and many more are now planned. We quantify from high-resolution SPOT 5 satellite images large-scale shoreline erosion and land loss between 2003 and 2012 that now affect over 50% of the once strongly advancing >600 km-long delta shoreline. Erosion, with no identified change in the river's discharge and in wave and wind conditions over this recent period, is consistent with: (1) a reported significant decrease in coastal surface suspended sediment from the Mekong that may be linked to dam retention of its sediment, (2) large-scale commercial sand mining in the river and delta channels, and (3) subsidence due to groundwater extraction. Shoreline erosion is already responsible for displacement of coastal populations. It is an additional hazard to the integrity of this Asian mega delta now considered particularly vulnerable to accelerated subsidence and sea-level rise, and will be exacerbated by future hydropower dams.

Compositional Characteristics of Dissolved Organic Matter released from the sediment of Han river in Korea.

NASA Astrophysics Data System (ADS)

Oh, H.; Choi, J. H.

2017-12-01

The dissolved organic matter (DOM) has variable characteristics depending on the sources. The DOM of a river is affected by rain water, windborne material, surface and groundwater flow, and sediments. In particular, sediments are sources and sinks of nutrients and pollutants in aquatic ecosystems by supplying large amounts of organic matter. The DOM which absorbs ultraviolet and visible light is called colored dissolved organic matter (CDOM). CDOM is responsible for the optical properties of natural waters in several biogeochemical and photochemical processes and absorbs UV-A (315-400 nm) and UV-B (280-315), which are harmful to aquatic ecosystems (Helms et al., 2008). In this study, we investigated the quantity and quality of DOM and CDOM released from the sediments of Han river which was impacted by anthropogenic activities and hydrologic alternation of 4 Major River Restoration Project. The target area of this study is Gangchenbo (GC), Yeojubo (YJ), and Ipobo(IP) of the Han River, Korea. Sediments and water samples were taken on July and August of 2016 and were incubated at 20° up to 7 days. Absorbance was measured with UV-visible spectrophotometer (Libra S32 PC, Biochrom). Fluorescence intensity determined with Fluorescence EEMs (F-7000, Hitachi). Absorbance and fluorescence intensity were used to calculate Specific Ultraviolet Absorbance (SUVA254), Humification index (HIX), Biological index (BIX), Spectral slope (SR) and component analysis. The DOC concentration increased after 3 days of incubation. According to the SUVA254 analysis, the microbial activity is highest in the initial overlying water of IP. HIX have range of 1.35-4.08, and decrease poly aromatic structures of organic matter during incubation. From the results of the BIX, autochthonous organic matter was released from the sediments. In all sites, Humic-like DOM, Microbial humic-like DOM and Protein-like DOM increased significantly between Day 0 and 3(except Humic-like, Microbial humic-like DOM in IP). Spectral slope ratio of all sites increased according to incubation, which means that the amount of CDOM increased from the sediment to overlying water.

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

USGS Publications Warehouse

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

2018-01-01

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

Rare earth elements in fine-grained sediments of major rivers from the high-standing island of Taiwan

NASA Astrophysics Data System (ADS)

Li, Chuan-Shun; Shi, Xue-Fa; Kao, Shuh-Ji; Liu, Yan-Guang; Lyu, Hua-Hua; Zou, Jian-Jun; Liu, Sheng-Fa; Qiao, Shu-Qing

2013-06-01

Thirty-eight sediment samples from 15 primary rivers on Taiwan were retrieved to characterize the rare earth element (REE) signature of fluvial fine sediment sources. Compared to the three large rivers on the Chinese mainland, distinct differences were observed in the REE contents, upper continental crust normalized patterns and fractionation factors of the sediment samples. The average REE concentrations of the Taiwanese river sediments are higher than those of the Changjiang and Huanghe, but lower than the Zhujiang. Light rare earth elements (LREEs) are enriched relative to heavy rare earth elements (HREEs) with ratios from 7.48 to 13.03. We found that the variations in (La/Lu)UCC-(Gd/Lu)UCC and (La/Yb)UCC-(Gd/Yb)UCC are good proxies for tracing the source sediments of Taiwanese and Chinese rivers due to their distinguishable values. Our analyses indicate that the REE compositions of Taiwanese river sediments were primarily determined by the properties of the bedrock, and the intensity of chemical weathering in the drainage areas. The relatively high relief and heavy rainfall also have caused the REEs in the fluvial sediments from Taiwan to be transported to the estuaries down rivers from the mountains, and in turn delivered nearly coincidently to the adjacent seas by currents and waves. Our studies suggest that the REE patterns of the river sediments from Taiwan are distinguishable from those from the other sources of sediments transported into the adjacent seas, and therefore are useful proxies for tracing the provenances and dispersal patterns of sediments, as well as paleoenvironmental changes in the marginal seas.

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

NASA Astrophysics Data System (ADS)

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

2018-06-01

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

Chemical data and lead isotopic compositions of geochemical baseline samples from streambed sediments and smelter slag, lead isotopic compositions in fluvial tailings, and dendrochronology results from the Boulder River watershed, Jefferson County, Montana

USGS Publications Warehouse

Unruh, Daniel M.; Fey, David L.; Church, Stan E.

2000-01-01

IntroductionAs a part of the U.S. Geological Survey Abandoned Mine Lands Initiative, metal-mining related wastes in the Boulder River study area in northern Jefferson County, Montana, have been evaluated for their environmental effects. The study area includes a 24-km segment of the Boulder River in and around Basin, Montana and three principal tributaries to the Boulder River: Basin Creek, Cataract Creek, and High Ore Creek. Mine and prospect waste dumps and mill wastes are located throughout the drainage basins of these tributaries and in the Boulder River. Mine-waste material has been transported into and down streams, where it has mixed with and become incorporated into the streambed sediments. In some localities, mine waste material was placed directly in stream channels and was transported downstream forming fluvial tailings deposits along the stream banks. Water quality and aquatic habitat have been affected by trace-element-contaminated sediment that moves from mine wastes into and down streams during snowmelt and storm runoff events within the Boulder River watershed.Present-day trace element concentrations in the streambed sediments and fluvial tailings have been extensively studied. However, in order to accurately evaluate the impact of mining on the stream environments, it is also necessary to evaluate the pre-mining trace-element concentrations in the streambed sediments. Three types of samples have been collected for estimation of pre-mining concentrations: 1) streambed sediment samples from the Boulder River and its tributaries located upstream from historical mining activity, 2) stream terrace deposits located both upstream and downstream of the major tributaries along the Boulder River, and 3) cores through sediment in overbank deposits, in abandoned stream channels, or beneath fluvial tailings deposits. In this report, we present geochemical data for six stream-terrace samples and twelve sediment-core samples and lead isotopic data for six terrace and thirteen core samples. Sample localities are in table 1 and figures 1 and 2, and site and sample descriptions are in table 2.Geochemical data have been presented for cores through fluvial tailings on High Ore Creek, on upper Basin Creek, and on Jack Creek and Uncle Sam Gulch. Geochemical and lead isotopic data for modern streambed-sediment samples have been presented by Fey and others.Lead isotopic determinations in bed sediments have been shown to be an effective tool for evaluating the contributions from various sources to the metals in bed sediments. However, in order to make these calculations, the lead isotopic compositions of the contaminant sources must also be known. Consequently, we have determined the lead isotopic compositions of five streambed-sediment samples heavily contaminated with fluvial mine waste immediately downstream from large mines in the Boulder River watershed in order to determine the lead isotopic signatures of the contaminants. Summary geochemical data for the contaminants are presented here and geochemical data for the streambed-sediment samples are given by Fey and others.Downstream from the Katie mill site and Jib tailings, fluvial deposits of mill tailings are present on a 10-m by 50-m bar in the Boulder River below the confluence with Basin Creek. The source of these tailings is not known, but fluvial tailings are also present immediately downstream from the Katie mill site, which is immediately upstream from the confluence with Basin Creek. Nine cores of fluvial tailings from this bar were analyzed.Dendrochronology samples were taken at several stream terrace localities to provide age control on the stream terrace deposits. Trees growing on the surfaces of stream terraces provide a minimum age for the terrace deposits, although floods subsequent to the trees' growth could have deposited post-mining overbank deposits around the trees. Historical data were also used to provide estimates of minimum ages of cultural features and to bracket the age of events.

Regional Big Injun (Price/Pocono) subsurface stratigraphy of West Virginia

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

Donaldson, A.C.; Zou, Xiangdong

1992-01-01

The lower Big Injun (Lower Mississippian) is the oil reservoir of the Granny Creek and Rock Creek fields and consists of multiple sandstones that were deposited in different fluvial-deltaic depositional environments. These multiple sandstones became amalgamated and now appear as a widespread blanket sandstone as a result of ancient cut and fill processes associated with river-channel sedimentation. The regional study of this Price Formation subsurface equivalent considers the continuity and thickness variations of the composite sandstones of the Big Injun mainly within western West Virginia. The major fluvial drainage system apparently flowed southward through Ohio (much of it later erodedmore » by the pre-Pottsville unconformity) during Big Injun time (and earlier) and part of the system was diverted into southwestern West Virginia as vertically stacked channel and river-mouth bar deposits (Rock Creek field). This ancient Ontario River system apparently drained a huge area including the northern craton as well as the orogenic belt. The emerging West Virginia Dome probably sourced the sediment transported by small rivers developing southwestward prograding deltas across Clay County (Granny Creek field). Sedimentation was affected by differential subsidence in the basin. Paleovalley fill was considered for areas with vertically stacked sandstones, but evidence for their origin is not convincing. Oil-reservoir sandstones are classified as dip-trending river channel (D1) and deltaic shoreline (D2) deposits.« less

Holocene delta evolution and sediment discharge of the Mekong River, southern Vietnam

NASA Astrophysics Data System (ADS)

Ta, Thi Kim Oanh; Nguyen, Van Lap; Tateishi, Masaaki; Kobayashi, Iwao; Tanabe, Susumu; Saito, Yoshiki

2002-09-01

Evolutionary changes, delta progradation, and sediment discharge of the Mekong River Delta, southern Vietnam, during the late Holocene are presented based on detailed analyses of samples from six boreholes on the lower delta plain. Sedimentological and chronostratigraphic analyses indicate clearly that the last 3 kyr were characterized by delta progradation under increasing wave influence, southeastward sediment dispersal, decreasing progradation rates, beach-ridge formation, and steepening of the face of the delta front. Estimated sediment discharge of the Mekong River for the last 3 kyr, based on sediment-volume analysis, was 144±36 million t yr -1 on average, or almost the same as the present level. The constant rate of delta front migration and stable sediment discharge during the last 3 kyr indicate that a dramatic increase in sediment discharge owing to human activities, as has been suggested for the Yellow River watershed, did not occur. Although Southeast Asian rivers have been considered candidates for such dramatic increases in discharge during the last 2 kyr, the Mekong River example, although it is a typical, large river of this region, does not support this hypothesis. Therefore, estimates of the millennial-scale global pristine sediment flux to the oceans must be revised.

Sediment and water chemistry of the San Juan River and Escalante River deltas of Lake Powell, Utah, 2010-2011

USGS Publications Warehouse

Hornewer, Nancy J.

2014-01-01

Recent studies have documented the presence of trace elements, organic compounds including polycyclic aromatic hydrocarbons, and radionuclides in sediment from the Colorado River delta and from sediment in some side canyons in Lake Powell, Utah and Arizona. The fate of many of these contaminants is of significant concern to the resource managers of the National Park Service Glen Canyon National Recreation Area because of potential health impacts to humans and aquatic and terrestrial species. In 2010, the U.S. Geological Survey began a sediment-core sampling and analysis program in the San Juan River and Escalante River deltas in Lake Powell, Utah, to help the National Park Service further document the presence or absence of contaminants in deltaic sediment. Three sediment cores were collected from the San Juan River delta in August 2010 and three sediment cores and an additional replicate core were collected from the Escalante River delta in September 2011. Sediment from the cores was subsampled and composited for analysis of major and trace elements. Fifty-five major and trace elements were analyzed in 116 subsamples and 7 composited samples for the San Juan River delta cores, and in 75 subsamples and 9 composited samples for the Escalante River delta cores. Six composited sediment samples from the San Juan River delta cores and eight from the Escalante River delta cores also were analyzed for 55 low-level organochlorine pesticides and polychlorinated biphenyls, 61 polycyclic aromatic hydrocarbon compounds, gross alpha and gross beta radionuclides, and sediment-particle size. Additionally, water samples were collected from the sediment-water interface overlying each of the three cores collected from the San Juan River and Escalante River deltas. Each water sample was analyzed for 57 major and trace elements. Most of the major and trace elements analyzed were detected at concentrations greater than reporting levels for the sediment-core subsamples and composited samples. Low-level organochlorine pesticides and polychlorinated biphenyls were not detected in any of the samples. Only one polycyclic aromatic hydrocarbon compound was detected at a concentration greater than the reporting level for one San Juan composited sample. Gross alpha and gross beta radionuclides were detected at concentrations greater than reporting levels for all samples. Most of the major and trace elements analyzed were detected at concentrations greater than reporting levels for water samples.

The role of extreme floods in estuary-coastal behaviour: contrasts between river- and tide-dominated microtidal estuaries

NASA Astrophysics Data System (ADS)

Cooper, J. A. G.

2002-06-01

Contrasting modes of sedimentation and facies arrangement in tide- and river-dominated microtidal estuaries arise from the degree to which river or tidal discharge and sediment supply influences an estuary. A distinct facies gradation exists in tide-dominated systems from sandy, barrier/tidal delta-associated environments at the coast through deep mud-dominated middle reaches to fluvial sediment in the upper reaches. In river-dominated systems, fluvial sediment extends to the barrier and flood-tidal deltas are poorly developed or absent from the estuary. A number of independent observations during extreme floods on the South African coast indicate that these types of estuary respond differently to extreme river floods and that the mode of response corresponds to estuary type. Tide-dominated systems exhibit preferential erosion of noncohesive barrier and tidal delta sediments during river floods while the middle reaches remain little modified. River-dominated systems experience consistent erosion throughout their channel length during extreme floods. The increased cohesion of riverine sediments and stabilisation of bars by vegetation in river-dominated channels means that higher magnitude floods are necessary to effect significant morphological change. Barrier erosion, including the tidal delta, results in deposition of an ephemeral delta composed almost entirely of sands from these deposits in tide-dominated estuaries. In river-dominated systems, eroded channel sediments and material from the river catchment may augment barrier sediments in the ephemeral delta deposit. Post-flood, wave-reworking of ephemeral delta sediments acts to restore barriers to pre-flood morphology within a few years; however, in river-dominated systems, the additional sediment volume may produce significant coastal progradation that requires several years or decades to redistribute. These different modes of flood response mediated by the nature of the estuary have implications for coastal behaviour at the time scale of months to several decades. Estuary-coastal behaviour at river-dominated estuaries may be influenced for several decades by post-flood morphological adjustment. Tide-dominated estuaries, however, respond more rapidly in reworking flood-eroded sediment and are typically fully adjusted to modal wave and tidal conditions within a few months to a few years. In addition, the facies arrangement within the two estuary types renders tide-dominated estuaries more responsive to minor floods, while river-dominated estuaries, by virtue of more cohesive channel sediments, require greater discharges to effect significant morphological change.

Suspended sediment delivery to Puget Sound from the lower Nisqually River, western Washington, July 2010–November 2011

USGS Publications Warehouse

Curran, Christopher A.; Grossman, Eric E.; Magirl, Christopher S.; Foreman, James R.

2016-05-26

On average, the Nisqually River delivers about 100,000 metric tons per year (t/yr) of suspended sediment to Puget Sound, western Washington, a small proportion of the estimated 1,200,000 metric tons (t) of sediment reported to flow in the upper Nisqually River that drains the glaciated, recurrently active Mount Rainier stratovolcano. Most of the upper Nisqually River sediment load is trapped in Alder Lake, a reservoir completed in 1945. For water year 2011 (October 1, 2010‒September 30, 2011), daily sediment and continuous turbidity data were used to determine that 106,000 t of suspended sediment were delivered to Puget Sound, and 36 percent of this load occurred in 2 days during a typical winter storm. Of the total suspended-sediment load delivered to Puget Sound in the water year 2011, 47 percent was sand (particle size >0.063 millimeters), and the remainder (53 percent) was silt and clay. A sediment-transport curve developed from suspended-sediment samples collected from July 2010 to November 2011 agreed closely with a curve derived in 1973 using similar data-collection methods, indicating that similar sediment-transport conditions exist. The median annual suspended-sediment load of 73,000 t (water years 1980–2014) is substantially less than the average load, and the correlation (Pearson’s r = 0.80, p = 8.1E-9, n=35) between annual maximum 2-day sediment loads and normalized peak discharges for the period indicates the importance of wet years and associated peak discharges of the lower Nisqually River for sediment delivery to Puget Sound. The magnitude of peak discharges in the lower Nisqually River generally is suppressed by flow regulation, and relative to other free-flowing, glacier-influenced rivers entering Puget Sound, the Nisqually River delivers proportionally less sediment because of upstream sediment trapping from dams.

Interplay between spatially explicit sediment sourcing, hierarchical river-network structure, and in-channel bed material sediment transport and storage dynamics

NASA Astrophysics Data System (ADS)

Czuba, Jonathan A.; Foufoula-Georgiou, Efi; Gran, Karen B.; Belmont, Patrick; Wilcock, Peter R.

2017-05-01

Understanding how sediment moves along source to sink pathways through watersheds—from hillslopes to channels and in and out of floodplains—is a fundamental problem in geomorphology. We contribute to advancing this understanding by modeling the transport and in-channel storage dynamics of bed material sediment on a river network over a 600 year time period. Specifically, we present spatiotemporal changes in bed sediment thickness along an entire river network to elucidate how river networks organize and process sediment supply. We apply our model to sand transport in the agricultural Greater Blue Earth River Basin in Minnesota. By casting the arrival of sediment to links of the network as a Poisson process, we derive analytically (under supply-limited conditions) the time-averaged probability distribution function of bed sediment thickness for each link of the river network for any spatial distribution of inputs. Under transport-limited conditions, the analytical assumptions of the Poisson arrival process are violated (due to in-channel storage dynamics) where we find large fluctuations and periodicity in the time series of bed sediment thickness. The time series of bed sediment thickness is the result of dynamics on a network in propagating, altering, and amalgamating sediment inputs in sometimes unexpected ways. One key insight gleaned from the model is that there can be a small fraction of reaches with relatively low-transport capacity within a nonequilibrium river network acting as "bottlenecks" that control sediment to downstream reaches, whereby fluctuations in bed elevation can dissociate from signals in sediment supply.

Measuring Bedload Sediment Flux in Large Rivers: New Data from the Mekong River and Its Applications in Assessing Geomorphic Change

NASA Astrophysics Data System (ADS)

Best, J.; Hackney, C. R.; Parsons, D. R.; Darby, S. E.; Leyland, J.; Aalto, R. E.; Nicholas, A. P.

2014-12-01

Many large rivers are undergoing renewed and increasing anthropogenic-induced change as water diversions, new dams and greater water demands place enhanced stresses on these river basins. Examples of rivers undergoing significant change include the Amazon, Madeira, Nile, Yangtze and Mekong, with considerable ongoing debate raging as to the long-term geomorphic and ecological effects of major anthropogenic interventions. Assessing the effects of such change in large rivers is demanding, one reason being that sediment transport is often exceedingly difficult to measure, and thus data needed to inform the debate on the impact of anthropogenic change is frequently lacking. Here, we report on one aspect of research being undertaken as part of STELAR-S2S - Sediment Transfer and Erosion on Large Alluvial Rivers - that is seeking to better understand the relationship between climate, anthropogenic impacts and sediment transport in some of the world's largest rivers. We are using the Lower Mekong River as our study site, with the Mekong delta being one of only three in the world classified by the IPCC as 'extremely vulnerable' to future changes in climate. Herein, we describe details of bedload sediment flux estimation using repeated high-resolution multibeam echo sounder (MBES) bathymetric mapping along the Lower Mekong and Tonle Sap rivers in Cambodia. We are using MBES to quantify the spatial variation in sediment transport both along and also across the river at 11 sites in the study area. Predicted increases in the extraction of sediment from the river through sand dredging are thought likely to cause a significant decrease in downstream sediment flux, and future dam construction along the Mekong main channel potentially offers another source of significant change. These field results will be set in the light of these anthropogenic drivers on sediment flux in the Mekong River and their possible future effects on bar formation and channel migration.

Sediment supply as a driver of river evolution in the Amazon Basin

NASA Astrophysics Data System (ADS)

Ahmed, Joshua; Constantine, José Antonio; Dunne, Thomas; Legleiter, Carl; Lazarus, Eli D.

2015-04-01

The Amazon represents the only large river basin in the world where there is a sufficient range of sediment supplies and a lack of engineering controls to assess how sediment supply drives the evolution of meandering rivers. Despite recent analytical advances (Asahi et al., 2013; Pittaluga and Seminara, 2011), modern theory does not yet identify or explain the effects of externally imposed sediment supplies, a fundamental river characteristic, on meandering river evolution. These sediment supplies would be radically reduced by the construction of large dams proposed for the Amazon Basin (Finer and Jenkins, 2012). Here, we demonstrate that the sediment loads imposed by their respective drainage basins determine planform changes in lowland rivers across the Amazon. Our analysis, based on Landsat image sequences, indicates that rivers with high sediment loads draining the Andes and associated foreland basin experience annual migration rates that are on average four times faster than rivers with lower sediment loads draining the Central Amazon Trough and shields. Incidents of meander cutoff also occur more frequently along the rivers of the Andes and foreland basin, where the number of oxbows in the floodplains is more than twice that observed in the floodplains of the Central Amazon Trough and shields. Our results, which cannot be explained by differences in channel slope or hydrology, highlight the importance of sediment supply in modulating the ability of meandering alluvial rivers to reshape the floodplain environment through river migration. Asahi, K., Shimizu, Y., Nelson, J., Parker, G., 2013. Numerical simulation of river meandering with self-evolving banks. Journal of Geophysical Research: Earth Surface, 118(4), 2013JF002752. Finer, M., Jenkins, C.N., 2012. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity. PLOS One, 7(4), e35126. Pittaluga, M.B., Seminara, G., 2011. Nonlinearity and unsteadiness in river meandering: a review of progress in theory and modelling. Earth Surface Processes and Landforms, 36(1), 20-38.

Fluvial sediment transport and deposition following the 1991 eruption of Mount Pinatubo

USGS Publications Warehouse

Hayes, S.K.; Montgomery, D.R.; Newhall, C.G.

2002-01-01

The 1991 eruption of Mount Pinatubo generated extreme sediment yields from watersheds heavily impacted by pyroclastic flows. Bedload sampling in the Pasig-Potrero River, one of the most heavily impacted rivers, revealed negligible critical shear stress and very high transport rates that reflected an essentially unlimited sediment supply and the enhanced mobility of particles moving over a smooth, fine-grained bed. Dimensionless bedload transport rates in the Pasig-Potrero River differed substantially from those previously reported for rivers in temperate regions for the same dimensionless shear stress, but were similar to rates identified in rivers on other volcanoes and ephemeral streams in arid environments. The similarity between volcanically disturbed and arid rivers appears to arise from the lack of an armored bed surface due to very high relative sediment supply; in arid rivers, this is attributed to a flashy hydrograph, whereas volcanically disturbed rivers lack armoring due to sustained high rates of sediment delivery. This work suggests that the increases in sediment supply accompanying massive disturbance induce morphologic and hydrologic changes that temporarily enhance transport efficiency until the watershed recovers and sediment supply is reduced. ?? 2002 Elsevier Science B.V. All rights reserved.

Integrated observation and modelling of runoff and sediments across different compartments of semi-arid catchments and channel networks

NASA Astrophysics Data System (ADS)

Bronstert, Axel; Ramon, Batalla; Araújo José C., De; da Costa Alexandre, Cunha; Till, Francke; Andreas, Güntner; Jose, Lopez-Tarazon; George, Mamede; Müller Eva, N.

2010-05-01

About one-third of the global population currently lives in countries which experience conditions of water stress. Such regions, often located within dryland ecosystems, are exposed to the hazard that the available freshwater resources fail to meet the water demand in domestic, agricultural and industrial sectors. Water availability often relies on the retention of river runoff in artificial lakes and reservoirs. However, the water storage in reservoirs is often adversely affected by sedimentation as a result of soil erosion. Erosion of the land surface due to natural or anthropogenic reasons and deposition of the eroded material in reservoirs threatens the reliability of reservoirs as a source of water supply. To sustain future water supply, a quantification of the sediment export from large dryland catchments becomes indispensable. A comprehensive modelling framework for water and sediment transport at the meso-scale, with a particular focus on dryland regions, has been developed from a German, Catalonian and Brazilian team during the last decade. It includes novel components for erosion from erosion-prone hillslopes, sediment transfer, retention and re-mobilization through the river system and sediment distribution, trapping and transfer through a reservoir. The parameterisation for pilot catchments is based on field monitoring campaigns of water and sediment fluxes, the analysis of land-use patterns, and the identification of the sediment hot spots through remotely sensed data. We present results of erosion-prone landscape units, the role of sediment transport in the river system, and the sedimentation processes in reservoirs. The modelling studies demonstrate the wide range of environmental problems where the model may be employed to develop sustainable management strategies for land and water resources. Evaluation of scenarios (land use, climate change) combined with an integrated assessment of options in reservoir management opens the opportunity to address relevant questions of water management including problems of water yield, reservoir capacity and economical comparison of on-/ offsite sediment management.

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

USGS Publications Warehouse

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

2014-01-01

High streamflow associated with the April–July 2011 Mississippi River flood forced the simultaneous opening of the three major flood-control structures in the lower Mississippi-Atchafalaya River subbasin for the first time in history in order to manage the amount of water moving through the system. The U.S. Geological Survey (USGS) collected samples for analysis of field properties, suspended-sediment concentration, particle-size, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, and up to 136 pesticides at 11 water-quality stations and 2 flood-control structures in the lower Mississippi-Atchafalaya River subbasin from just above the confluence of the upper Mississippi and Ohio Rivers downstream from April through July 2011. Monthly fluxes of suspended sediment, suspended sand, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, atrazine, simazine, metolachlor, and acetochlor were estimated at 9 stations and 2 flood-control structures during the flood period. Although concentrations during the 2011 flood were within the range of what has been observed historically, concentrations decreased during peak streamflow on the lower Mississippi River. Prior to the 2011 flood, high concentrations of suspended sediment and nitrate were observed in March 2011 at stations downstream of the confluence of the upper Mississippi and Ohio Rivers, which probably resulted in a loss of available material for movement during the flood. In addition, the major contributor of streamflow to the lower Mississippi-Atchafalaya River subbasin during April and May was the Ohio River, whose water contained lower concentrations of suspended sediment, pesticides, and nutrients than water from the upper Mississippi River. Estimated fluxes for the 4-month flood period were still quite high and contributed approximately 50 percent of the estimated annual suspended sediment, nitrate, and total phosphorus fluxes in 2011; the largest fluxes were estimated at the water-quality station located at Vicksburg, Mississippi. The majority of the suspended-sediment flux introduce into the lower Mississippi-Atchafalaya River subbasin during the 2011 flood was in the form of fine-grained particles from the upper Mississippi River—77 percent of the suspended-sediment flux compared to 23 percent from the Ohio River. As water moved downstream along the lower Mississippi River, there were losses in suspended-sediment flux because of deposition and backwater areas. Fluxes showed a greater response to increased streamflow in the Atchafalaya River than in the lower Mississippi River. The result was a gain in suspended-sediment flux with distance downstream in the Atchafalaya River because of resuspension of previously deposited materials—particularly sand particles. Overall, 13 percent less suspended sediment left the lower Mississippi-Atchafalaya River subbasin than entered it from the confluence of the upper Mississippi and Ohio Rivers during the flood. The loss in suspended-sediment flux during the flood accounted for 14 percent of the 2011 annual suspended-sediment flux loss within the lower Mississippi-Atchafalaya River subbasin. Nitrate composed approximately 70 percent of the total nitrogen flux at all of the sampled water-quality stations, excluding the Arkansas River. Almost 2.4 times more nitrate flux entered the lower Mississippi-Atchafalaya River subbasin from the upper Mississippi River than from the Ohio River. As nitrate moved down the lower Mississippi River and the Atchafalaya River, there were no substantial losses or gains in flux, indicating that nitrate moved conservatively within the subbasin during the 2011 flood. Although streamflow was the largest on record, nitrate flux during the flood period resulted in a zone of hypoxia in the Gulf of Mexico that was only the tenth largest on record. The flux of total phosphorus in the lower Mississippi-Atchafalaya River subbasin during the 2011 flood was strongly related to suspended-sediment flux at most of the stations. There were significant gains in total phosphorus flux in the Atchafalaya River during the flood period and losses between the stations along the lower Mississippi River. Overall, however, the amount of total phosphorus flux that left the lower Mississippi-Atchafalaya River subbasin was only 1.7 percent less than the flux that entered it from the upper Mississippi River and the Ohio River, indicating that total phosphorus flux within the subbasin during the flood was conservative. As streamflow was decreasing within the lower Mississippi-Atchafalaya River subbasin, orthophosphate composed an increasing percentage of the total phosphorus concentration, probably because of the return of waters low in oxygen concentration from areas such as inundated lands, backwater streams, and floodways. Poorly oxygenated waters promote the release of sediment-bound phosphorus into the more-readily available dissolved form (measured as orthophosphate in this study). Because of processing within the subbasin during the flood period, there was a 25-percent gain in orthophosphate flux between the confluence of the upper Mississippi and Ohio Rivers and the outlet of the subbasin. Of the 136 pesticide compounds and degradates that were analyzed, only 18 were detected above the method reporting level. The 18 compounds that were detected fell into three categories: (1) compounds that were frequently detected and showed a response in concentration to the flood; (2) compounds that were detected in almost every sample at every station but at low concentrations; and (3) compounds that were infrequently detected. Fluxes for the most frequently detected pesticides having the highest concentrations (atrazine, metolachlor, acetochlor, and simazine) were within the low-to-middle range of historic fluxes. An average of 66,450 cubic feet per second of streamflow was diverted from the lower Mississippi River through the Morganza Floodway into the Atchafalaya River from May 14 through July 7, 2011. Dissolved oxygen concentrations in the floodway decreased with the amount of time that the flood control structure was open, which affected nitrate and orthophosphate concentrations. As dissolved oxygen concentrations decreased in the floodway, nitrate concentrations decreased and orthophosphate concentrations increased. Oil and gas samples were also collected at 1 station upstream and 1 station downstream from the outlet of the Morganza Floodway into the Atchafalaya River. There were no detections of petroleum hydrocarbons in the upstream or downstream samples. All concentrations of oil and grease were relatively low, and the effect of water from the floodway on water quality in the Atchafalaya River could not be determined because oil and grease samples were not collected from the floodway.

Flood-related contamination in catchments affected by historical metal mining: an unexpected and emerging hazard of climate change.

PubMed

Foulds, S A; Brewer, P A; Macklin, M G; Haresign, W; Betson, R E; Rassner, S M E

2014-04-01

Floods in catchments affected by historical metal mining result in the remobilisation of large quantities of contaminated sediment from floodplain soils and old mine workings. This poses a significant threat to agricultural production and is preventing many European river catchments achieving a 'good chemical and ecological status', as demanded by the Water Framework Directive. Analysis of overbank sediment following widespread flooding in west Wales in June 2012 showed that flood sediments were contaminated above guideline pollution thresholds, in some samples by a factor of 82. Most significantly, silage produced from flood affected fields was found to contain up to 1900 mg kg(-1) of sediment associated Pb, which caused cattle poisoning and mortality. As a consequence of climate related increases in flooding this problem is likely to continue and intensify. Management of contaminated catchments requires a geomorphological approach to understand the spatial and temporal cycling of metals through the fluvial system. Copyright © 2013 Elsevier B.V. All rights reserved.

Design of a sediment-monitoring gaging network on ephemeral tributaries of the Colorado River in Glen, Marble, and Grand Canyons, Arizona

USGS Publications Warehouse

Griffiths, Ronald E.; Topping, David J.; Anderson, Robert S.; Hancock, Gregory S.; Melis, Theodore S.

2014-01-01

Management of sediment in rivers downstream from dams requires knowledge of both the sediment supply and downstream sediment transport. In some dam-regulated rivers, the amount of sediment supplied by easily measured major tributaries may overwhelm the amount of sediment supplied by the more difficult to measure lesser tributaries. In this first class of rivers, managers need only know the amount of sediment supplied by these major tributaries. However, in other regulated rivers, the cumulative amount of sediment supplied by the lesser tributaries may approach the total supplied by the major tributaries. The Colorado River downstream from Glen Canyon has been hypothesized to be one such river. If this is correct, then management of sediment in the Colorado River in the part of Glen Canyon National Recreation Area downstream from the dam and in Grand Canyon National Park may require knowledge of the sediment supply from all tributaries. Although two major tributaries, the Paria and Little Colorado Rivers, are well documented as the largest two suppliers of sediment to the Colorado River downstream from Glen Canyon Dam, the contributions of sediment supplied by the ephemeral lesser tributaries of the Colorado River in the lowermost Glen Canyon, and Marble and Grand Canyons are much less constrained. Previous studies have estimated amounts of sediment supplied by these tributaries ranging from very little to almost as much as the amount supplied by the Paria River. Because none of these previous studies relied on direct measurement of sediment transport in any of the ephemeral tributaries in Glen, Marble, or Grand Canyons, there may be significant errors in the magnitudes of sediment supplies estimated during these studies. To reduce the uncertainty in the sediment supply by better constraining the sediment yield of the ephemeral lesser tributaries, the U.S. Geological Survey Grand Canyon Monitoring and Research Center established eight sediment-monitoring gaging stations beginning in 2000 on the larger of the previously ungaged tributaries of the Colorado River downstream from Glen Canyon Dam. The sediment-monitoring gaging stations consist of a downward-looking stage sensor and passive suspended-sediment samplers. Two stations are equipped with automatic pump samplers to collect suspended-sediment samples during flood events. Directly measuring discharge and collecting suspended-sediment samples in these remote ephemeral streams during significant sediment-transporting events is nearly impossible; most significant run-off events are short-duration events (lasting minutes to hours) associated with summer thunderstorms. As the remote locations and short duration of these floods make it prohibitively expensive, if not impossible, to directly measure the discharge of water or collect traditional depth-integrated suspended-sediment samples, a method of calculating sediment loads was developed that includes documentation of stream stages by field instrumentation, modeling of discharges associated with these stages, and automatic suspended-sediment measurements. The approach developed is as follows (1) survey and model flood high-water marks using a two-dimensional hydrodynamic model, (2) create a stage-discharge relation for each site by combining the modeled flood flows with the measured stage record, (3) calculate the discharge record for each site using the stage-discharge relation and the measured stage record, and (4) calculate the instantaneous and cumulative sediment loads using the discharge record and suspended-sediment concentrations measured from samples collected with passive US U-59 samplers and ISCOTM pump samplers. This paper presents the design of the gaging network and briefly describes the methods used to calculate discharge and sediment loads. The design and methods herein can easily be used at other remote locations where discharge and sediment loads are required.

Small river plumes off the northeastern coast of the Black Sea under average climatic and flooding discharge conditions

NASA Astrophysics Data System (ADS)

Osadchiev, Alexander; Korshenko, Evgeniya

2017-06-01

This study focuses on the impact of discharges of small rivers on the delivery and fate of fluvial water and suspended matter at the northeastern part of the Black Sea under different local precipitation conditions. Several dozens of mountainous rivers flow into the sea at the study region, and most of them, except for several of the largest, have little annual runoff and affect adjacent coastal waters to a limited extent under average climatic conditions. However, the discharges of these small rivers are characterized by a quick response to precipitation events and can significantly increase during and shortly after heavy rains, which are frequent in the considered area. The delivery and fate of fluvial water and terrigenous sediments at the study region, under average climatic and rain-induced flooding conditions, were explored and compared using in situ data, satellite imagery, and numerical modeling. It was shown that the point-source spread of continental discharge dominated by several large rivers under average climatic conditions can change to the line-source discharge from numerous small rivers situated along the coast in response to heavy rains. The intense line-source runoff of water and suspended sediments forms a geostrophic alongshore current of turbid and freshened water, which induces the intense transport of suspended and dissolved constituents discharged with river waters in a northwestern direction. This process significantly influences water quality and causes active sediment load at large segments of the narrow shelf at the northeastern part of the Black Sea compared to average climatic discharge conditions.

Small river plumes near the north-eastern coast of the Black Sea under climatic mean and flooding discharge conditions

NASA Astrophysics Data System (ADS)

Osadchiev, Alexander; Korshenko, Evgeniya

2017-04-01

The study is focused on the impact of discharge from small rivers on propagation and final location of fluvial waters and suspended matter at the north-eastern part of the Black Sea under different local precipitation conditions. Several dozens of mountainous rivers inflow into the sea at the studied region and most of them, except the several largest of them, have small annual runoff and limitedly affect adjacent coastal waters under climatic mean conditions. However, discharges of these small rivers are characterized by quick response to precipitation events and can dramatically increase during and shortly after heavy rains, which are frequent in the area under consideration. Propagation and final location of fluvial waters and terrigenous sediments at the studied region under climatic mean and rain-induced flooding conditions were explored and compared using in situ data, satellite imagery and numerical modelling. It was shown that the point-source spread of continental discharge dominated by several large rivers during climatic mean conditions can change to the line-source discharge from numerous small rivers situated along the coast in response to heavy rains. Intense line-source runoff of water and suspended sediments form a geostrophic alongshore current of turbid and freshened water, which induces intense transport of suspended and dissolved constituents discharged with river waters in a north-western direction. This process significantly influences water quality and causes active sediment load at large segments of narrow shelf at the north-eastern part of the Black Sea as compared to climatic mean discharge conditions.

Transport of Water, Carbon, and Sediment Through the Yukon River Basin

USGS Publications Warehouse

Brabets, Timothy P.; Schuster, Paul F.

2008-01-01

INTRODUCTION In 2001, the U.S. Geological Survey (USGS) began a water-quality study of the Yukon River. The Yukon River Basin (YRB), which encompasses 330,000 square miles in northwestern Canada and central Alaska (fig. 1), is one of the largest and most diverse ecosystems in North America. The Yukon River is more than 1,800 miles long and is one of the last great uncontrolled rivers in the world, and is essential to the eastern Bering Sea and Chukchi Sea ecosystems, providing freshwater runoff, sediments, and nutrients (Brabets and others, 2000). Despite its remoteness, recent studies (Hinzman and others, 2005; Walvoord and Striegl, 2007) indicate the YRB is changing. These changes likely are in response to a warming trend in air temperature of 1.7i??C from 1951 to 2001 (Hartmann and Wendler, 2005). As a result of this warming trend, permafrost is thawing in the YRB, ice breakup occurs earlier on the main stem of the Yukon River and its tributaries, and timing of streamflow and movement of carbon and sediment through the basin is changing (Hinzman and others, 2005; Walvoord and Striegl, 2007). One of the most striking characteristics in the YRB is its seasonality. In the YRB, more than 75 percent of the annual streamflow runoff occurs during a five month period, May through September. This is important because streamflow determines when, where, and how much of a particular constituent will be transported. As an example, more than 95 percent of all sediment transported during an average year also occurs during this period (Brabets and others, 2000). During the other 7 months, streamflow, concentrations of sediment and other water-quality constituents are low and little or no sediment transport occurs in the Yukon River and its tributaries. Streamflow and water-quality data have been collected at more than 50 sites in the YRB (Dornblaser and Halm, 2006; Halm and Dornblaser, 2007). Five sites have been sampled more than 30 times and others have been sampled twice during peak- and low-flow conditions as part of synoptic sampling campaigns. Although the synoptic data do not provide a complete picture of water quality of a particular river through the year, the data do provide a snapshot of water-quality conditions at a particular time of year. Two constituents of interest are suspended sediment and dissolved organic carbon (DOC). Suspended sediment is important because elevated concentrations can adversely affect aquatic life by obstructing fish gills, covering fish spawning sites, and altering habitat of benthic organisms. Metals and organic contaminants also tend to adsorb onto fine-grained sediment. Permafrost thawing has major implications for the carbon cycle. It is critical to understand the processes related to the transport of DOC to surface waters and how long-term climatic changes may alter these processes (Schuster and others, 2004).

Contrasts in Sediment Delivery and Dispersal from River Mouth to Accumulation Zones in High Sediment Load Systems: Fly River, Papua New Guinea and Waipaoa River, New Zealand

NASA Astrophysics Data System (ADS)

Ogston, A. S.; Walsh, J. P.; Hale, R. P.

2011-12-01

The relationships between sediment-transport processes, short-term sedimentary deposition, subsequent burial, and long-term accumulation are critical to understanding the morphological development of the continental margin. This study focuses on processes involved in formation and evolution of the clinoform in the Gulf of Papua, Papua New Guinea in which much of the riverine sediment accumulates, and comparison to those processes active off the Waipaoa River, New Zealand that form mid-shelf deposits and export sediment to the slope. In tidally dominated deltas, sediment discharged from the river sources must transit through an estuarine region located within the distributary channels, where particle pathways can undergo significant transformations. Within the distributaries of the Fly River tidally dominated delta, near-bed fluid-mud concentrations were observed at the estuarine turbidity maximum and sediment delivery to the nearshore was controlled by the morphology and gradient of the distributary. El Niño results in anonymously low flow and sediment discharge conditions, which limits transport of sediment from the distributaries to the nearshore zone of temporary storage. Because the sediment stored nearshore feeds the prograding clinoform, this perturbation propagates throughout the dispersal system. In wave-dominated regions, transport mechanisms actively move sediment away from the river source, separating the site of deposition and accumulation from the river mouth. River-flood and storm-wave events each create discrete deposits on the Waipaoa River shelf and data has been collected to determine their form, distribution, and relationship to factors such as flood magnitude or wave energy. In this case, transport pathways appear to be influenced by structurally controlled shelf bathymetry. In both cases, the combined fluvial and marine processes can initiate and maintain gravity-driven density flows, and although their triggers and controls differ vastly, these flows play a significant role in the morpholigcal development of the continental margin. These sites, synthesized with examples from multiple other environments, provide a basis for understanding the interactions between physical processes responsible for the transport of sediment from river mouths to the sites of ultimate deposition.

Large-scale dam removal on the Elwha River, Washington, USA: source-to-sink sediment budget and synthesis

USGS Publications Warehouse

Warrick, Jonathan A.; Bountry, Jennifer A.; East, Amy E.; Magirl, Christopher S.; Randle, Timothy J.; Gelfenbaum, Guy R.; Ritchie, Andrew C.; Pess, George R.; Leung, Vivian; Duda, Jeff J.

2015-01-01

Understanding landscape responses to sediment supply changes constitutes a fundamental part of many problems in geomorphology, but opportunities to study such processes at field scales are rare. The phased removal of two large dams on the Elwha River, Washington, exposed 21 ± 3 million m3, or ~ 30 million tonnes (t), of sediment that had been deposited in the two former reservoirs, allowing a comprehensive investigation of watershed and coastal responses to a substantial increase in sediment supply. Here we provide a source-to-sink sediment budget of this sediment release during the first two years of the project (September 2011–September 2013) and synthesize the geomorphic changes that occurred to downstream fluvial and coastal landforms. Owing to the phased removal of each dam, the release of sediment to the river was a function of the amount of dam structure removed, the progradation of reservoir delta sediments, exposure of more cohesive lakebed sediment, and the hydrologic conditions of the river. The greatest downstream geomorphic effects were observed after water bodies of both reservoirs were fully drained and fine (silt and clay) and coarse (sand and gravel) sediments were spilling past the former dam sites. After both dams were spilling fine and coarse sediments, river suspended-sediment concentrations were commonly several thousand mg/L with ~ 50% sand during moderate and high river flow. At the same time, a sand and gravel sediment wave dispersed down the river channel, filling channel pools and floodplain channels, aggrading much of the river channel by ~ 1 m, reducing river channel sediment grain sizes by ~ 16-fold, and depositing ~ 2.2 million m3 of sand and gravel on the seafloor offshore of the river mouth. The total sediment budget during the first two years revealed that the vast majority (~ 90%) of the sediment released from the former reservoirs to the river passed through the fluvial system and was discharged to the coastal waters, where slightly less than half of the sediment was deposited in the river-mouth delta. Although most of the measured fluvial and coastal deposition was sand-sized and coarser (> 0.063 mm), significant mud deposition was observed in and around the mainstem river channel and on the seafloor. Woody debris, ranging from millimeter-size particles to old-growth trees and stumps, was also introduced to fluvial and coastal landforms during the dam removals. At the end of our two-year study, Elwha Dam was completely removed, Glines Canyon Dam had been 75% removed (full removal was completed 2014), and ~ 65% of the combined reservoir sediment masses—including ~ 8 Mt of fine-grained and ~ 12 Mt of coarse-grained sediment—remained within the former reservoirs. Reservoir sediment will continue to be released to the Elwha River following our two-year study owing to a ~ 16 m base level drop during the final removal of Glines Canyon Dam and to erosion from floods with larger magnitudes than occurred during our study. Comparisons with a geomorphic synthesis of small dam removals suggest that the rate of sediment erosion as a percent of storage was greater in the Elwha River during the first two years of the project than in the other systems. Comparisons with other Pacific Northwest dam removals suggest that these steep, high-energy rivers have enough stream power to export volumes of sediment deposited over several decades in only months to a few years. These results should assist with predicting and characterizing landscape responses to future dam removals and other perturbations to fluvial and coastal sediment budgets.

Comparison of Cottonwood Dendrochronology and Optically Stimulated Luminescence Geochronometers Along a High Plains Meandering River, Powder River, Montana, USA

NASA Astrophysics Data System (ADS)

Hasse, T. R.; Schook, D. M.

2017-12-01

Geochronometers at centennial scales can aid our understanding of process rates in fluvial geomorphology. Plains cottonwood trees (Populus deltoides ssp. Monilifera) in the high plains of the United States are known to germinate on freshly created deposits such as point bars adjacent to rivers. As the trees mature they may be partially buried (up to a few meters) by additional flood deposits. Cottonwood age gives a minimum age estimate of the stratigraphic surface where the tree germinated and a maximum age estimate for overlying sediments, providing quantitative data on rates of river migration and sediment accumulation. Optically Stimulated Luminescence (OSL) of sand grains can be used to estimate the time since the sand grains were last exposed to sunlight, also giving a minimum age estimate of sediment burial. Both methods have disadvantages: Browsing, partial burial, and other damage to young cottonwoods can increase the time required for the tree to reach a height where it can be sampled with a tree corer, making the germination point a few years to a few decades older than the measured tree age; fluvial OSL samples can have inherited age (when the OSL age is older than the burial age) if the sediment was not completely bleached prior to burial. We collected OSL samples at 8 eroding banks of the Powder River Montana, and tree cores at breast height (±1.2 m) from cottonwood trees growing on the floodplain adjacent to the OSL sample locations. Using the Minimum Age Model (MAM) we found that OSL ages appear to be 500 to 1,000 years older than the adjacent cottonwood trees which range in age (at breast height) from 60 to 185 years. Three explanations for this apparent anomaly in ages are explored. Samples for OSL could be below a stratigraphic unconformity relative to the cottonwood germination elevation. Shallow samples for OSL could be affected by anthropogenic mixing of sediments due to plowing and leveling of hay fields. The OSL samples could have significant inherited ages due to partial bleaching during sediment transport in this high plains river with high suspended sediment loads. The dendrochronology of the adjacent cottonwood trees then offers an independent measurement of the inherited age of the OSL samples.

Modeling of Soil Erosion by IntErO model: The Case Study of the Novsicki Potok Watershed, of the Prokletije high mountains of Montenegro

NASA Astrophysics Data System (ADS)

Spalevic, Velibor; Al-Turki, Ali M.; Barovic, Goran; Leandro Naves Silva, Marx; Djurovic, Nevenka; Soares Souza, Walisson; Veloso Gomes Batista, Pedro; Curovic, Milic

2016-04-01

The application of soil conservation programs to combat erosion and sedimentation are significantly contributing to the protection of the natural resources. Watershed management practices include the assessment of Physical-Geographical, Climate, Geological, Pedological characteristics, including the analysis of Land Use of the regions concerned. The policy makers are increasingly looking for the different land uses and climatic scenarios that can be used for valuable projections for watershed management. To increase knowledge about those processes, use of hydrological and soil erosion models is needed and that is allowing quantification of soil redistribution and sediment productions. We focused on soil erosion processes in one of Northern Montenegrin mountain watersheds, the Novsicki Potok Watershed of the Polimlje River Basin, using modeling techniques: the IntErO model for calculation of runoff and soil loss. The model outcomes were validated through measurements of lake sediment deposition at the Potpec hydropower plant dam. Our findings indicate a medium potential of soil erosion risk. With 464 m³ yr-1 of annual sediment yield, corresponding to an area-specific sediment yield of 270 m³km-2 yr-1, the Novsicki Potok drainage basin belongs to the Montenegrin basins with the medium sediment discharge; according to the erosion type, it is surface erosion. The value of the Z coefficient was calculated on 0.403, what indicates that the river basin belongs to 3rd destruction category (of five). Our results suggest that the calculated peak discharge from the river basin was 82 m3s-1 for the incidence of 100 years. According to our analysis there is a possibility for large flood waves to appear in the studied river basin. With this research we, to some extent, improved the knowledge on the status of sediment yield and runoff of the river basins of Montenegro, where the map of Soil erosion is still not prepared. The IntErO model we used in this study is relatively novel concept and is highly recommended for soil erosion modelling in other river basins similar to the studied watershed, because of its simple identification of critical areas affected by the soil loss caused by soil erosion.

Pesticide concentrations in water and in suspended and bottom sediments in the New and Alamo rivers, Salton Sea Watershed, California, April 2003

USGS Publications Warehouse

LeBlanc, Lawrence A.; Orlando, James L.; Kuivila, Kathryn

2004-01-01

This report contains pesticide concentration data for water, and suspended and bed sediment samples collected in April 2003 from twelve sites along the New and Alamo Rivers in the Salton Sea watershed, in southeastern California. The study was done in collaboration with the California State Regional Water Quality Control Board, Colorado River Region, to assess inputs of current-use pesticides associated with water and sediment into the New and Alamo Rivers. Five sites along the New River and seven sites along the Alamo River, downstream of major agricultural drains, were selected and covered the lengths of the rivers from the international boundary to approximately 1.5 km from the river mouths. Sampling from bridges occurred at seven of the twelve sites. At these sites, streamflow measurements were taken. These same sites were also characterized for cross-stream homogeneity by measuring dissolved oxygen, pH, specific conductance, temperature, and suspended solids concentration at several vertical (depths) and horizontal (cross-stream) points across the river. Large volume water samples (200?300 L) were collected for isolation of suspended sediments by flow-through centrifugation. Water from the outflow of the flow-through centrifuge was sampled for the determination of aqueous pesticide concentrations. In addition, bottom sediments were sampled at each site. Current-use pesticides and legacy organochlorine compounds (p,p'-DDT, p,p'-DDE and p,p'-DDD) were extracted from sediments and measured via gas chromatography/mass spectrometry (GC/MS). Organic carbon and percentage of fines were also determined for suspended and bottom sediments. Cross-stream transects of dissolved constituents and suspended sediments showed that the rivers were fairly homogeneous at the sites sampled. Streamflow was higher at the outlet sites, with the Alamo River having higher flow (1,240 cfs) than the New River (798 cfs). Twelve current-use pesticides, one legacy organochlorine compound (p,p'-DDE), and the additive piperonyl butoxide were detected in water samples. Trifluralin was found in the highest concentration of all detected compounds (68.5?599 ng/L) at all sites in both rivers, except for the international boundary sites. Atrazine was also detected in high concentration (51.0?285 ng/L) at several sites. The outlet sites had among the highest numbers of pesticides detected and the international boundary sites had the lowest numbers of pesticides detected for both rivers. The numbers of pesticides detected were greater for the Alamo River than for the New River. Six current-use pesticides and two legacy organochlorines (p,p'-DDE and p,p'-DDD) were found associated with suspended and bed sediments. The DDT metabolite p,p'-DDE was detected in all suspended and bed sediments from the Alamo River, but only at two sites in the New River. Dacthal, chlorpyrifos, pendimethalin, and trifluralin were the most commonly detected current-use pesticides. Trifluralin was the compound found in the highest concentrations in suspended (14.5?120 ng/g) and bed (1.9?9.0 ng/g) sediments. The sites along the Alamo River had more frequent detections of pesticides in suspended and bed sediments when compared with the New River sites. The greatest number of pesticides that were detected in suspended sediments (seven) were in the samples from the Sinclair Road and Harris Road sites. For bottom sediments, the Alamo River outlet site had the greatest number of pesticide detections (eight).

Analysis of mutagenic activity of biohazardous organics in Kanawha River sediments. Technical completion report

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

White, A.R.; Waldron, M.C.

1988-01-01

Residual chemical contamination of Kanawha River sediments may constitute a health hazard. Sediment cores have been analyzed using a coupled bioassay/chemical fractionation procedure. Both bacterial mutagenicity and sister chromatid exchange (SCE) analyses were conducted on sediment samples. Pocatalico River sediments extracts showed no response in either bacterial mutagenicity assay or SCE assay. Extracts from Armour Creek and the Kanawha River induced mutagenicities in the presence of S9 enzymes. The same extracts produced a significant increase in human chromosomal cross-over events.

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

USGS Publications Warehouse

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

2012-01-01

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.

Annual suspended sediment and trace element fluxes in the Mississippi, Columbia, Colorado, and Rio Grande drainage basins

USGS Publications Warehouse

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

2001-01-01

Suspended sediment, sediment-associated, total trace element, phosphorus (P), and total organic carbon (TOC) fluxes were determined for the Mississippi, Columbia, Rio Grande, and Colorado Basins for the study period (the 1996, 1997, and 1998 water years) as part of the US Geological Survey's redesigned National Stream Quality Accounting Network (NASQAN) programme. The majority (??? 70%) of Cu, Zn, Cr, Ni, Ba, P, As, Fe, Mn, and Al are transported in association with suspended sediment; Sr transport seems dominated by the dissolved phase, whereas the transport of Li and TOC seems to be divided equally between both phases. Average dissolved trace element levels are markedly lower than reported during the original NASQAN programme; this seems due to the use of 'clean' sampling, processing, and analytical techniques rather than to improvements in water quality. Partitioning between sediment and water for Ag, Pb, Cd, Cr, Co, V, Be, As, Sb, Hg, and Ti could not be estimated due to a lack of detectable dissolved concentrations in most samples. Elevated suspended sediment-associated Zn levels were detected in the Ohio River Basin and elevated Hg levels were detected in the Tennessee River, the former may affect the mainstem Mississippi River, whereas the latter probably do not. Sediment-associated concentrations of Ag, Cu, Pb, Zn, Cd, Cr, Co, Ba, Mo, Sb, Hg, and Fe are markedly elevated in the upper Columbia Basin, and appear to be detectable (Zn, Cd) as far downstream as the middle of the basin. These elevated concentrations seem to result from mining and/or mining-related activities. Consistently detectable concentrations of dissolved Se were found only in the Colorado River Basin. Calculated average annual suspended sediment fluxes at the mouths of the Mississippi and Rio Grande Basins were below, whereas those for the Columbia and Colorado Basins were above previously published annual values. Downstream suspended sediment-associated and total trace element fluxes increase in the Mississippi and Columbia Basins, whereas fluxes markedly decrease in the Colorado Basin. No consistent pattern in trace element fluxes was detected in the Rio Grande Basin.

Spatio-temporal monitoring of suspended sediments in the Solimões River (2000-2014)

NASA Astrophysics Data System (ADS)

Espinoza-Villar, Raul; Martinez, Jean-Michel; Armijos, Elisa; Espinoza, Jhan-Carlo; Filizola, Naziano; Dos Santos, Andre; Willems, Bram; Fraizy, Pascal; Santini, William; Vauchel, Philippe

2018-01-01

The Amazon River sediment discharge has been estimated at between 600 and 1200 Mt/year, of which more than 50% comes from the Solimões River. Because of the area's inaccessibility, few studies have examined the sediment discharge spatial and temporal pattern in the upper Solimões region. In this study, we use MODIS satellite images to retrieve and understand the spatial and temporal behaviour of suspended sediments in the Solimões River from Peru to Brazil. Six virtual suspended sediment gauging stations were created along the Solimões River on a 2050-km-long transect. At each station, field-derived river discharge estimates were available and field-sampling trips were conducted for validation of remote-sensing estimates during different periods of the annual hydrological cycle between 2007 and 2014. At two stations, 10-day surface suspended sediment data were available from the SO-HYBAM monitoring program (881 field SSS samples). MODIS-derived sediment discharge closely matched the field observations, showing a relative RMSE value of 27.3% (0.48 Mtday) overall. Satellite-retrieved annual sediment discharge at the Tamshiyacu (Peru) and Manacapuru (Brazil) stations is estimated at 521 and 825 Mt/year, respectively. While upstream the river presents one main sediment discharge peak during the hydrological cycle, a secondary sediment discharge peak is detected downstream during the declining water levels, which is induced by sediment resuspension from the floodplain, causing a 72% increase on average from June to September.

The potential for dams to impact lowland meandering river floodplain geomorphology.

PubMed

Marren, Philip M; Grove, James R; Webb, J Angus; Stewardson, Michael J

2014-01-01

The majority of the world's floodplains are dammed. Although some implications of dams for riverine ecology and for river channel morphology are well understood, there is less research on the impacts of dams on floodplain geomorphology. We review studies from dammed and undammed rivers and include influences on vertical and lateral accretion, meander migration and cutoff formation, avulsion, and interactions with floodplain vegetation. The results are synthesized into a conceptual model of the effects of dams on the major geomorphic influences on floodplain development. This model is used to assess the likely consequences of eight dam and flow regulation scenarios for floodplain geomorphology. Sediment starvation downstream of dams has perhaps the greatest potential to impact on floodplain development. Such effects will persist further downstream where tributary sediment inputs are relatively low and there is minimal buffering by alluvial sediment stores. We can identify several ways in which floodplains might potentially be affected by dams, with varying degrees of confidence, including a distinction between passive impacts (floodplain disconnection) and active impacts (changes in geomorphological processes and functioning). These active processes are likely to have more serious implications for floodplain function and emphasize both the need for future research and the need for an "environmental sediment regime" to operate alongside environmental flows.

The Potential for Dams to Impact Lowland Meandering River Floodplain Geomorphology

PubMed Central

Marren, Philip M.; Grove, James R.; Webb, J. Angus; Stewardson, Michael J.

2014-01-01

The majority of the world's floodplains are dammed. Although some implications of dams for riverine ecology and for river channel morphology are well understood, there is less research on the impacts of dams on floodplain geomorphology. We review studies from dammed and undammed rivers and include influences on vertical and lateral accretion, meander migration and cutoff formation, avulsion, and interactions with floodplain vegetation. The results are synthesized into a conceptual model of the effects of dams on the major geomorphic influences on floodplain development. This model is used to assess the likely consequences of eight dam and flow regulation scenarios for floodplain geomorphology. Sediment starvation downstream of dams has perhaps the greatest potential to impact on floodplain development. Such effects will persist further downstream where tributary sediment inputs are relatively low and there is minimal buffering by alluvial sediment stores. We can identify several ways in which floodplains might potentially be affected by dams, with varying degrees of confidence, including a distinction between passive impacts (floodplain disconnection) and active impacts (changes in geomorphological processes and functioning). These active processes are likely to have more serious implications for floodplain function and emphasize both the need for future research and the need for an “environmental sediment regime” to operate alongside environmental flows. PMID:24587718

Mineralogical characteristics of sediments and heavy metal mobilization along a river watershed affected by acid mine drainage.

PubMed

Xie, Yingying; Lu, Guining; Yang, Chengfang; Qu, Lu; Chen, Meiqin; Guo, Chuling; Dang, Zhi

2018-01-01

Trace-element concentrations in acid mine drainage (AMD) are primarily controlled by the mineralogy at the sediment-water interface. Results are presented for a combined geochemical and mineralogical survey of Dabaoshan Mine, South China. Developed sequential extraction experiments with the analysis of the main mineralogical phases by semi-quantitative XRD, differential X-ray diffraction (DXRD) and scanning electron microscopy (SEM) were conducted to identify the quantitative relationship between iron minerals and heavy metals. Results showed that schwertmannite, jarosite, goethite and ferrihydrite were the dominant Fe-oxyhydroxide minerals which were detected alternately in the surface sediment with the increasing pH from 2.50 to 6.93 along the Hengshi River. Decreasing contents of schwertmannite ranging from 35 wt % to 6.5 wt % were detected along the Hengshi River, which was corresponding to the decreasing metal contents. The easily reducible fractions exert higher affinity of metals while compared with reducible and relatively stable minerals. A qualitative analysis of heavy metals extracted from the sediments indicated that the retention ability varied: Pb > Mn > Zn > As ≈ Cu > Cr > Cd ≈ Ni. Results in this study are avail for understanding the fate and transport of heavy metals associated with iron minerals and establishing the remediation strategies of AMD systems.

Mineralogical characteristics of sediments and heavy metal mobilization along a river watershed affected by acid mine drainage

PubMed Central

Xie, Yingying; Yang, Chengfang; Qu, Lu; Chen, Meiqin; Guo, Chuling; Dang, Zhi

2018-01-01

Trace-element concentrations in acid mine drainage (AMD) are primarily controlled by the mineralogy at the sediment-water interface. Results are presented for a combined geochemical and mineralogical survey of Dabaoshan Mine, South China. Developed sequential extraction experiments with the analysis of the main mineralogical phases by semi-quantitative XRD, differential X-ray diffraction (DXRD) and scanning electron microscopy (SEM) were conducted to identify the quantitative relationship between iron minerals and heavy metals. Results showed that schwertmannite, jarosite, goethite and ferrihydrite were the dominant Fe-oxyhydroxide minerals which were detected alternately in the surface sediment with the increasing pH from 2.50 to 6.93 along the Hengshi River. Decreasing contents of schwertmannite ranging from 35 wt % to 6.5 wt % were detected along the Hengshi River, which was corresponding to the decreasing metal contents. The easily reducible fractions exert higher affinity of metals while compared with reducible and relatively stable minerals. A qualitative analysis of heavy metals extracted from the sediments indicated that the retention ability varied: Pb > Mn > Zn > As ≈ Cu > Cr > Cd ≈ Ni. Results in this study are avail for understanding the fate and transport of heavy metals associated with iron minerals and establishing the remediation strategies of AMD systems. PMID:29304091

Effects of sustained-release composite on the oxygen levels and sediment phosphorus fractions of an urban river in Shanghai.

PubMed

Li, Yang; Zhou, Yanbo; Zhou, Zhenhua; Wang, Ningsheng; Zhou, Qiang; Wang, Fuchen

2014-01-01

The eutrophication of many rivers and lakes is attributed to the anoxia and the increasing internal loading of nutrients from sediment. A novel sustained-release composite (SRC) synthesis of stearic acid and calcium peroxide (CaO2) was applied to supply a water body with oxygen endured in this study. The influences of SRC on the dissolved oxygen (DO) level, pH and total phosphorus (TP) of an urban river in Shanghai were studied. The results show that SRC has a longer oxygen-releasing cycle and a more tender effect on pH with the comparison of CaO2 powder. Reduction of 79.6% in the concentration of TP was observed in the water column. After 35 days of SRC addition, there was a significant positive correlation between TP and DO. As a consequence, the phosphorus fractions in sediment, including loosely sorbed P (NH4Cl-P), redox-sensitive P (Fe-P), calcium bound P (Ca-P), aluminium bound P (Al-P) and residual P (organic and refractory P) were affected by the addition of SRC. The NH4Cl-P and Fe-P fractions in the sediment that could release P easily were well constrained under the positive effect of SRC.

Sediment Transport in the Lower Yampa River, Northwestern Colorado

USGS Publications Warehouse

Elliott, John G.; Kircher, James E.; Von Guerard, Paul

1984-01-01

Discharge measurements and sediment samples were taken at streamflow-gaging station 09260050 Yampa River at Deerlodge Park in 1982 and 1983 to determine the annual sediment supply to the Yampa Canyon in Dinosaur National Monument. Forty-three years of discharge records at two tributary sites were combined to determine the historic discharge of the Yampa River at Deerlodge Park. A mean annual hydrograph and flow-duration curve were derived from these data. Sediment-transport equations were derived for total sediment discharge, suspended-sediment discharge, bedload dischagre, and the discharge of sediment in several particle-sizes. Annual sediment discharge were determined by the flow-duration, sediment-rating-curve method and indicated annual total sediment discharge was approximately 2.0 million tons per year of which 0.8 million tons per year was sand-sized material. Bedload was almost entirely sand, and annual bedload discharge was 0.1 million tons per year. Development of water resources in the Yampa River basin could effect the geomorphic character of the Yampa River at Deerlodge Park and the Yampa Canyon. Several scenarios of altered streamflow frequency distribution, reduced streamflow volume, and reduced sediment supply are examined to estimate the effect on the sediment budget at Deerlodge Park. (USGS)

Mercury contamination of riverine sediments in the vicinity of a mercury cell chlor-alkali plant in Sagua River, Cuba.

PubMed

Bolaños-Álvarez, Yoelvis; Alonso-Hernández, Carlos Manuel; Morabito, Roberto; Díaz-Asencio, Misael; Pinto, Valentina; Gómez-Batista, Miguel

2016-06-01

Sediment is a great indicator for assessing coastal mercury contamination. The objective of this study was to assess the magnitude of mercury pollution in the sediments of the Sagua River, Cuba, where a mercury-cell chlor-alkali plant has operated since the beginning of the 1980s. Surface sediments and a sediment core were collected in the Sagua River and analyzed for mercury using an Advanced Mercury Analyser (LECO AMA-254). Total mercury concentrations ranged from 0.165 to 97 μg g(-1) dry weight surface sediments. Enrichment Factor (EF), Index of Geoaccumulation (Igeo) and Sediment Quality Guidelines were applied to calculate the degrees of sediment contamination. The EF showed the significant role of anthropogenic mercury inputs in sediments of the Sagua River. The result also determined that in all stations downstream from the chlor-alkali plant effluents, the mercury concentrations in the sediments were higher than the Probable Effect Levels value, indicating a high potential for adverse biological effects. The Igeo index indicated that the sediments in the Sagua River are evaluated as heavily polluted to extremely contaminated and should be remediated as a hazardous material. This study could provide the latest benchmark of mercury pollution and prove beneficial to future pollution studies in relation to monitoring works in sediments from tropical rivers and estuaries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Clay mineralogy indicates the muddy sediment provenance in the estuarine-inner shelf of the East China Sea

NASA Astrophysics Data System (ADS)

Zhao, Yifei; Zou, Xinqing; Liu, Qing; Wang, Chenglong; Ge, Chendong; Xu, Min

2018-02-01

The estuarine-inner shelf mud regions of the East China Sea (ECS) are valuable for studying the source-to-sink processes of fluvial sediments deposited since the Holocene. In this study, we present evidence of the provenance and environmental evolution of two cores (S5-2 and JC07) from the estuarine-inner shelf regions of the ECS over the past 100 years based on 210Pb dating, high-resolution grain size measurements and clay mineral analyses. The results indicate that the clay mineral assemblages of cores S5-2 and JC07 are dominated by illite, followed by kaolinite and chlorite, and present scarce amounts of smectite. A comparison of these clay mineral assemblages with several major sources reveals that the fine sediments on the estuarine-inner shelf of the ECS represent a mixture of provenances associated with the Yangtze and Yellow Rivers, as well as smaller rivers. However, the contribution of each provenance has varied greatly over the past hundred years, as indicated by the down-core variability due to strong sediment reworking and transport on the inner shelf and the reduction of the sediment load from the Yangtze River basin. In the mud region of the Yangtze River estuary, the sediment from 1930 to 1956 was primarily derived from the Yangtze River, although the Yellow River was also an important influence. From 1956 to 2013, the Yellow River contribution decreased, whereas the Yangtze River contribution correspondingly increased. In the Zhe-Min mud region, the Yangtze River contributed more sediment than did other rivers from 1910 to 1950; however, the Yangtze River contribution gradually decreased from 1950 to 2013. Moreover, the other small rivers accounted for minor contributions, and the East Asian winter monsoon (EAWM) played an important role in the sediment transport process in the ECS. Our results indicate that the weakening/strengthening of the EAWM and a decrease in the sediment load of the Yangtze River influenced the transport and fate of sediment on the estuarine-inner shelf of the ECS.

Stream-sediment geochemistry in mining-impacted streams : sediment mobilized by floods in the Coeur d'Alene-Spokane River system, Idaho and Washington

USGS Publications Warehouse

Box, Stephen E.; Bookstrom, Arthur A.; Ikramuddin, Mohammed

2005-01-01

Environmental problems associated with the dispersion of metal-enriched sediment into the Coeur d'Alene-Spokane River system downstream from the Coeur d'Alene Mining District in northern Idaho have been a cause of litigation since 1903, 18 years after the initiation of mining for lead, zinc, and silver. Although direct dumping of waste materials into the river by active mining operations stopped in 1968, metal-enriched sediment continues to be mobilized during times of high runoff and deposited on valley flood plains and in Coeur d'Alene Lake (Horowitz and others, 1993). To gauge the geographic and temporal variations in the metal contents of flood sediment and to provide constraints on the sources and processes responsible for those variations, we collected samples of suspended sediment and overbank deposits during and after four high-flow events in 1995, 1996, and 1997 in the Coeur d'Alene-Spokane River system with estimated recurrence intervals ranging from 2 to 100 years. Suspended sediment enriched in lead, zinc, silver, antimony, arsenic, cadmium, and copper was detected over a distance of more than 130 mi (the downstream extent of sampling) downstream of the mining district. Strong correlations of all these elements in suspended sediment with each other and with iron and manganese are apparent when samples are grouped by reach (tributaries to the South Fork of the Coeur d'Alene River, the South Fork of the Coeur d'Alene River, the main stem of the Coeur d'Alene River, and the Spokane River). Elemental correlations with iron and manganese, along with observations by scanning electron microscopy, indicate that most of the trace metals are associated with Fe and Mn oxyhydroxide compounds. Changes in elemental correlations by reach suggest that the sources of metal-enriched sediment change along the length of the drainage. Metal contents of suspended sediment generally increase through the mining district along the South Fork of the Coeur d'Alene River, decrease below the confluence of the North and South Forks, and then increase again downstream of the gradient flattening below Cataldo. Metal contents of suspended sediment in the Spokane River below Coeur d'Alene Lake were comparable to those of suspended sediment in the main stem of the Coeur d'Alene River above the lake during the 1997 spring runoff, but with somewhat higher Zn contents. Daily suspended-sediment loads were about 100 times larger in the 1996 flood (50-100-year recurrence interval) than in the smaller 1997 floods (2-5-year recurrence intervals). Significant differences in metal ratios and contents are also apparent between the two flood types. The predominant source of suspended sediment in the larger 1996 flood was previously deposited, metal-enriched flood-plain sediment, identified by its Zn/Pb ratio less than 1. Suspended sediment in the smaller 1997 floods had metal ratios distinct from those of the flood-plain deposits and was primarily derived from metal-enriched sediment stored within the stream channel, identified by a Zn/Pb ratio greater than 1. Sediment deposited during overbank flooding on the immediate streambank or natural levee of the river typically consists of sandy material with metal ratios and contents similar to those of the sandy streambed sediment in the adjacent river reach. Samples of overbank deposits in backlevee marshes collected after the 1996 flood have metal ratios similar to those of peak-flow suspended sediment in the same river reach, but generally lower metal contents.

Flux of nitrogen, phosphorus, and suspended sediment from the Susquehanna River Basin to the Chesapeake Bay during Tropical Storm Lee, September 2011, as an indicator of the effects of reservoir sedimentation on water quality

USGS Publications Warehouse

Hirsch, Robert M.

2012-01-01

Concentrations of nitrogen, phosphorus, and suspended sediment are measured at the U.S. Geological Survey streamgage at Conowingo Dam at the downstream end of the Susquehanna River Basin in Maryland, where the river flows into the Chesapeake Bay. During the period September 7-15, 2011, in the aftermath of Tropical Storm Lee, concentrations of these three constituents were among the highest ever measured at this site. These measurements indicate that sediment-storage processes behind the three dams on the lower Susquehanna River are evolving. In particular, they indicate that scouring of sediment (and the nitrogen and phosphorus attached to that sediment) may be increasing with time. Trends in flow-normalized fluxes at the Susquehanna River at Conowingo, Maryland, streamgage during 1996-2011 indicate a 3.2-percent decrease in total nitrogen, but a 55-percent increase in total phosphorus and a 97-percent increase in suspended sediment. These large increases in the flux of phosphorus and sediment from the Susquehanna River to the Chesapeake Bay have occurred despite reductions in the fluxes of these constituents from the Susquehanna River watershed upstream from the reservoirs. Although the Tropical Storm Lee flood event contributed about 1.8 percent of the total streamflow from the Susquehanna River to the Chesapeake Bay over the past decade (water years 2002-11), it contributed about 5 percent of the nitrogen, 22 percent of the phosphorus, and 39 percent of the suspended sediment during the same period. These results highlight the importance of brief high-flow events in releasing nitrogen, phosphorus, and sediment derived from the Susquehanna River watershed and stored in the Conowingo Reservoir to the Chesapeake Bay.

Assessment of acid leachable trace metals in sediment cores from River Uppanar, Cuddalore, Southeast coast of India.

PubMed

Ayyamperumal, T; Jonathan, M P; Srinivasalu, S; Armstrong-Altrin, J S; Ram-Mohan, V

2006-09-01

An acid leachable technique is employed in core samples (C1, C2 and C3) to develop a baseline data on the sediment quality for trace metals of River Uppanar, Cuddalore, southeast coast of India. Acid leachable metals (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn and Cd) indicate peak values at the sulphidic phase and enrichment of metals in the surface layers are due to the anthropogenic activities. Association of trace metals with Fe, Mn indicates their adsorption onto Fe-Mn oxyhydroxides and their correlation with S indicate that they are precipitated as metal sulphides. Factor analysis identified three possible types of geochemical associations and the supremacy of trace metals along with Fe, Mn, S and mud supports their geochemical associations. Factor analysis also signifies that anthropogenic activities have affected both the estuarine and fresh water regions of River Uppanar.

Summertime conditions of a muddy estuarine environment: the EsCoSed project contribution.

PubMed

Brocchini, Maurizio; Calantoni, Joseph; Reed, Allen H; Postacchini, Matteo; Lorenzoni, Carlo; Russo, Aniello; Mancinelli, Alessandro; Corvaro, Sara; Moriconi, Giacomo; Soldini, Luciano

2015-01-01

As part of the Estuarine Cohesive Sediments (EsCoSed) project, a field experiment was performed in a highly engineered environment, acting as a natural laboratory, to study the physico-chemical properties of estuarine sediments and the associated hydro-morphodynamics during different seasons. The present contribution focuses on the results obtained from the summertime monitoring of the most downstream part of the Misa River (Senigallia, Italy). The measured hydrodynamics suggested a strong interaction between river current, wave forcing and tidal motion; flow velocities, affected by wind waves traveling upstream, changed significantly along the water column in both direction and magnitude. Surficial salinities in the estuary were low in the upper reaches of the estuary and exceeded 10 psu before the river mouth. Montmorillonite dominated the clay mineral assemblage, suggesting that large, low density flocs with high settling velocities (>1 mm s(-1)) may dominate the suspended aggregate materials.

Cyclic Sediment Trading Between Channel and River Bed Sediments

NASA Astrophysics Data System (ADS)

Haddadchi, A.

2015-12-01

Much of the previous work on sediment tracing has focused on determining either the initial sources of the sediment (soils derive from a particular rock type) or the erosion processes generating the sediment. However, alluvial stores can be both a source and sink for sediment transported by streams. Here geochemical and fallout radionuclide tracing of river-bed and alluvial sediments are used to determine the role of secondary sources, sediment stores, as potential sources of sediment leaving Emu Creek catchment, southeastern Queensland, Australia. Activity concentrations of 137Cs on the river sediments are consistent with channel erosion being the dominant source at all sites sampled along the river. To characterise the deposition and remobilisation cycles in the catchment, a novel geochemical tracing approach was used. Successive pockets of alluvium were treated as discrete sink terms within geochemical mixing models and their source contributions compared with those of river bed sediments collected adjacent to each alluvial pocket. Three different size fractions were examined; silts and clays (<10 μm), silts (10-63 μm), and fine sands (63-212 μm). The contribution of the initial soil/rock type sources to river bed and alluvial sediments at each sampling site was identical for all three different size fractions, but varied along the stream. Combining these findings it is concluded that proximal alluvial stores dominated the supply of sediment to the river at each location, with this being particularly evident at the catchment outlet. Identical contribution of rock type sources to both river bed and alluvial pockets together with the dominant erosion being from channel banks indicates a high degree of 'trading' between the fluvial space and the alluvial space. Hence, management works aimed at primarily reducing the supply of sediments to the outlet of Emu Creek should focus on rehabilitation of channel banks in the lower catchment.

What role do hurricanes play in sediment delivery to subsiding river deltas?

USGS Publications Warehouse

Smith, James E.; Bentley, Samuel J.; Snedden, Gregg; White, Crawford

2015-01-01

The Mississippi River Delta (MRD) has undergone tremendous land loss over the past century due to natural and anthropogenic influences, a fate shared by many river deltas globally. A globally unprecedented effort to restore and sustain the remaining subaerial portions of the delta is now underway, an endeavor that is expected to cost $50–100B over the next 50 yr. Success of this effort requires a thorough understanding of natural and anthropogenic controls on sediment supply and delta geomorphology. In the MRD, hurricanes have been paradoxically identified as both substantial agents of widespread land loss, and vertical marsh sediment accretion. We present the first multi-decadal chronostratigraphic assessment of sediment supply for a major coastal basin of the MRD that assesses both fluvial and hurricane-induced contributions to sediment accumulation in deltaic wetlands. Our findings indicate that over multidecadal timescales, hurricane-induced sediment delivery may be an important contributor for deltaic wetland vertical accretion, but the contribution from hurricanes to long-term sediment accumulation is substantially less than sediment delivery supplied by existing and planned river-sediment diversions at present-day river-sediment loads.

What Role do Hurricanes Play in Sediment Delivery to Subsiding River Deltas?

NASA Astrophysics Data System (ADS)

Smith, James E.; Bentley, Samuel J.; Snedden, Gregg A.; White, Crawford

2015-12-01

The Mississippi River Delta (MRD) has undergone tremendous land loss over the past century due to natural and anthropogenic influences, a fate shared by many river deltas globally. A globally unprecedented effort to restore and sustain the remaining subaerial portions of the delta is now underway, an endeavor that is expected to cost $50-100B over the next 50 yr. Success of this effort requires a thorough understanding of natural and anthropogenic controls on sediment supply and delta geomorphology. In the MRD, hurricanes have been paradoxically identified as both substantial agents of widespread land loss, and vertical marsh sediment accretion. We present the first multi-decadal chronostratigraphic assessment of sediment supply for a major coastal basin of the MRD that assesses both fluvial and hurricane-induced contributions to sediment accumulation in deltaic wetlands. Our findings indicate that over multidecadal timescales, hurricane-induced sediment delivery may be an important contributor for deltaic wetland vertical accretion, but the contribution from hurricanes to long-term sediment accumulation is substantially less than sediment delivery supplied by existing and planned river-sediment diversions at present-day river-sediment loads.

Environmental and eelgrass response to dike removal: Nisqually River Delta (2010–14)

USGS Publications Warehouse

Takesue, Renee K.

2016-10-03

Restoration of tidal flows to formerly diked marshland can alter land-to-sea fluxes and patterns of accumulation of terrestrial sediment and organic matter, and these tidal flows can also affect existing nearshore habitats. Dikes were removed from 308 hectares (ha) of the Nisqually National Wildlife Refuge on the Nisqually River Delta in south Puget Sound, Washington, in fall 2009 to improve habitat for wildlife, such as juvenile salmon. Ecologically important intertidal and subtidal eelgrass (Zostera marina) beds grow on the north and west margins of the delta. The goal of this study was to understand long-term changes in eelgrass habitat and their relation to dike removal. Sediment and eelgrass properties were monitored annually in May from 2010 to 2014 at two sites on the west side of the Nisqually River Delta along McAllister Creek, a spring-fed creek near two restored tidal channels. In May 2014, the mean canopy height of eelgrass was the same as in previous years in an 8-ha bed extending to the Nisqually River Delta front, but mean canopy height was 20 percent lower in a 0.3-ha eelgrass bed closer to the restored marsh when compared to mean canopy height of eelgrass in May 2010, 6 months after dike removal was completed. Over 5 years, the amount of eelgrass leaf area per square meter (m2) in the 8-ha bed increased slightly, and surface-sediment grain size became finer. In contrast, in the 0.3-ha bed, eelgrass leaf area per m2 decreased by 45 percent, and surface sediment coarsened. Other potential stressors, including sediment pore water reduction-oxidation potential (redox) and hydrogen sulfide (H2S) concentration in the eelgrass rhizosphere, or root zone, were below levels that negatively affect eelgrass growth and therefore did not appear to be environmental stressors on plants. Eelgrass biomass partitioning, though less favorable in the 8-ha eelgrass bed compared to the 0.3-ha one, was well above the critical above-ground to below-ground biomass ratio of 2:1 for Z. marina, an indication that these plants were not at risk of a carbon deficit during low-light conditions. After 5 years, nearshore changes associated with the restoration of tidal flows to formerly diked marshes of the Nisqually River Delta appeared to have little impact on the large eelgrass bed extending from Luhr Beach to the Nisqually River Delta front; however, restoration appears to be contributing to the decline of a small eelgrass bed closer to the restoration area.

Anticipated sediment delivery to the lower Elwha River during and following dam removal: Chapter 2 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

USGS Publications Warehouse

Czuba, Christiana R.; Randle, Timothy J.; Bountry, Jennifer A.; Magirl, Christopher S.; Czuba, Jonathan A.; Curran, Christopher A.; Konrad, Christopher P.; Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

2011-01-01

During and after the planned incremental removal of two large, century-old concrete dams between 2011 and 2014, the sediment-transport regime in the lower Elwha River of western Washington will initially spike above background levels and then return to pre-dam conditions some years after complete dam removal. Measurements indicate the upper reaches of the steep-gradient Elwha River, draining the northeast section of the Olympic Mountains, carries between an estimated 120,000 and 290,000 cubic meters of sediment annually. This large load has deposited an estimated 19 million cubic meters of sediment within the two reservoirs formed by the Elwha and Glines Canyon Dams. It is anticipated that from 7 to 8 million cubic meters of this trapped sediment will mobilize and transport downstream during and after dam decommissioning, restoring the downstream sections of the sediment-starved river and nearshore marine environments. Downstream transport of sediment from the dam sites will have significant effects on channel morphology, water quality, and aquatic habitat during and after dam removal. Sediment concentrations are expected to be between 200 and 1,000 milligrams per liter during and just after dam removal and could rise to as much as 50,000 milligrams per liter during high flows. Downstream sedimentation in the river channel and flood plain will be potentially large, particularly in the lower Elwha River, an alluvial reach with a wide flood plain. Overall aggradation could be as much as one to several meters. Not all reservoir sediment, however, will be released to the river. Some material will remain on hill slopes and flood plains within the drained reservoirs in quantities that will depend on the hydrology, precipitation, and mechanics of the incising channel. Eventually, vegetation will stabilize this remaining reservoir sediment, and the overall sediment load in the restored river will return to pre-dam levels.

A scheme to scientifically and accurately assess cadmium pollution of river sediments, through consideration of bioavailability when assessing ecological risk.

PubMed

Song, Zhixin; Tang, Wenzhong; Shan, Baoqing

2017-10-01

Evaluating heavy metal pollution status and ecological risk in river sediments is a complex task, requiring consideration of contaminant pollution levels, as well as effects of biological processes within the river system. There are currently no simple or low-cost approaches to heavy metal assessment in river sediments. Here, we introduce a system of assessment for pollution status of heavy metals in river sediments, using measurements of Cd in the Shaocun River sediments as a case study. This system can be used to identify high-risk zones of the river that should be given more attention. First, we evaluated the pollution status of Cd in the river sediments based on their total Cd content, and calculated a risk assessment, using local geochemical background values at various sites along the river. Using both acetic acid and ethylenediaminetetraacetic acid to extracted the fractions of Cd in sediments, and used DGT to evaluate the bioavailability of Cd. Thus, DGT provided a measure of potentially bioavailable concentrations of Cd concentrations in the sediments. Last, we measured Cd contents in plant tissue collected at the same site to compare with our other measures. A Pearson's correlation analysis showed that Cd-Plant correlated significantly with Cd-HAc, (r = 0.788, P < 0.01), Cd-EDTA (r = 0.925, P < 0.01), Cd-DGT (r = 0.976, P < 0.01), and Cd-Total (r = 0.635, P < 0.05). We demonstrate that this system of assessment is a useful means of assessing heavy metal pollution status and ecological risk in river sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

USGS Publications Warehouse

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

2016-01-01

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

Effects of the Upper Taum Sauk Reservoir Embankment Breach on the Surface-Water Quality and Sediments of the East Fork Black River and the Black River, Southeastern Missouri - 2006-07

USGS Publications Warehouse

Barr, Miya N.

2009-01-01

On December 14, 2005, a 680-foot wide section of the upper reservoir embankment of the Taum Sauk pump-storage hydroelectric powerplant located in Reynolds County, Missouri, suddenly failed. This catastrophic event sent approximately 1.5 billion gallons of water into the Johnson's Shut-Ins State Park and into the East Fork Black River, and deposited enormous quantities of rock, soil, and vegetation in the flooded areas. Water-quality data were collected within and below the impacted area to study and document the changes to the riverene system. Data collection included routine, event-based, and continuous surface-water quality monitoring as well as suspended- and streambed-sediment sampling. Surface water-quality samples were collected and analyzed for a suite of physical and chemical constituents including: turbidity; nutrients; major ions such as calcium, magnesium, and potassium; total suspended solids; total dissolved solids; trace metals such as aluminum, iron, and lead; and suspended-sediment concentrations. Suspended-sediment concentrations were used to calculate daily sediment discharge. A peculiar blue-green coloration on the water surface of the East Fork Black River and Black River was evident downstream from the lower reservoir during the first year of the study. It is possible that this phenomenon was the result of 'rock flour' occurring when the upper reservoir embankment was breached, scouring the mountainside and producing extremely fine sediment particles, or from the alum-based flocculent used to reduce turbidity in the lower reservoir. It also was determined that no long-term effects of the reservoir embankment breach are expected as the turbidity and concentrations of trace metals such as total recoverable aluminum, dissolved aluminum, dissolved iron, and suspended-sediment concentration graphically decreased over time. Larger concentrations of these constituents during the beginning of the study also could be a direct result of the alum-based flocculent used in the lower reservoir. Suspended-sediment concentrations and turbidity measurements were largest at the site downstream from the lower reservoir. This is because of the large amounts of debris deposited in the lower reservoir from the breach, which in turn were redeposited into the East Fork Black River during releases. When these constituents were plotted over time, the concentrations decreased and were similar to the other two sites in the study. Trend analyses were studied at one site with historical data. No major trends were discovered for streamflow, turbidity, suspended-sediment concentrations, or suspended-sediment discharges before or after the event. Although long-term effects of the elevated turbidity, major trace metals, and suspended sediments in the study area as a result of the reservoir embankment breach are not expected, there could possibly be other effects not measured during this study that could potentially affect the surface-water quality, such as loss of riparian habitat, changes in biological ecosystems, and large-scale reworking of sediments.

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

USGS Publications Warehouse

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

2009-01-01

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

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

NASA Astrophysics Data System (ADS)

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

2013-12-01

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

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

USGS Publications Warehouse

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

2013-01-01

Sedimentation is an ongoing maintenance problem for reservoirs, limiting reservoir storage capacity and navigation. Because Lower Granite Reservoir in Washington is the most upstream of the four U.S. Army Corps of Engineers reservoirs on the lower Snake River, it receives and retains the largest amount of sediment. In 2008, in cooperation with the U.S. Army Corps of Engineers, the U.S. Geological Survey began a study to quantify sediment transport to Lower Granite Reservoir. Samples of suspended sediment and bedload were collected from streamgaging stations on the Snake River near Anatone, Washington, and the Clearwater River at Spalding, Idaho. Both streamgages were equipped with an acoustic Doppler velocity meter to evaluate the efficacy of acoustic backscatter for estimating suspended-sediment concentrations and transport. In 2009, sediment sampling was extended to 10 additional locations in tributary watersheds to help identify the dominant source areas for sediment delivery to Lower Granite Reservoir. Suspended-sediment samples were collected 9–15 times per year at each location to encompass a range of streamflow conditions and to capture significant hydrologic events such as peak snowmelt runoff and rain-on-snow. Bedload samples were collected at a subset of stations where the stream conditions were conducive for sampling, and when streamflow was sufficiently high for bedload transport. At most sampling locations, the concentration of suspended sediment varied by 3–5 orders of magnitude with concentrations directly correlated to streamflow. The largest median concentrations of suspended sediment (100 and 94 mg/L) were in samples collected from stations on the Palouse River at Hooper, Washington, and the Salmon River at White Bird, Idaho, respectively. The smallest median concentrations were in samples collected from the Selway River near Lowell, Idaho (11 mg/L), the Lochsa River near Lowell, Idaho (11 mg/L), the Clearwater River at Orofino, Idaho (13 mg/L), and the Middle Fork Clearwater River at Kooskia, Idaho (15 mg/L). The largest measured concentrations of suspended sediment (3,300 and 1,400 mg/L) during a rain-on-snow event in January 2011 were from samples collected at the Potlatch River near Spalding, Idaho, and the Palouse River at Hooper, Washington, respectively. Generally, samples collected from agricultural watersheds had a high percentage of silt and clay-sized suspended sediment, whereas samples collected from forested watersheds had a high percentage of sand. During water years 2009–11, Lower Granite Reservoir received about 10 million tons of suspended sediment from the combined loads of the Snake and Clearwater Rivers. The Snake River accounted for about 2.97 million tons per year (about 89 percent) of the total suspended sediment, 1.48 million tons per year (about 90 percent) of the suspended sand, and about 1.52 million tons per year (87 percent) of the suspended silt and clay. Of the suspended sediment transported to Lower Granite Reservoir, the Salmon River accounted for about 51 percent of the total suspended sediment, about 56 percent of the suspended sand, and about 44 percent of the suspended silt and clay. About 6.2 million tons (62 percent) of the sediment contributed to Lower Granite Reservoir during 2009–11 entered during water year 2011, which was characterized by an above average winter snowpack and sustained spring runoff. A comparison of historical data collected from the Snake River near Anatone with data collected during this study indicates that concentrations of total suspended sediment and suspended sand in the Snake River were significantly smaller during water years 1972–79 than during 2008–11. Most of the increased sediment content in the Snake River is attributable to an increase of sand-size material. During 1972–79, sand accounted for an average of 28 percent of the suspended-sediment load; during 2008–11, sand accounted for an average of 48 percent. Historical data from the Clearwater River at Spalding indicates that the concentrations of total suspended sediment collected during 1972–79 were not significantly different from the concentrations measured during this study. However, the suspended-sand concentrations in the Clearwater River were significantly smaller during 1972–79 than during 2008–11. The increase in suspended-sand concentrations in the Snake and Clearwater Rivers are probably attributable to numerous severe forest fires that burned large areas of central Idaho from 1980–2010. Acoustic backscatter from an acoustic Doppler velocity meter proved to be an effective method of estimating suspended-sediment concentration and load for most streamflow conditions in the Snake and Clearwater Rivers. Models based on acoustic backscatter were able to simulate most of the variability in suspended-sediment concentrations in the Clearwater River at Spalding (coefficient of determination [R2]=0.93) and the Snake River near Anatone (R2=0.92). Acoustic backscatter seems to be especially effective for estimating suspended-sediment concentration and load over short (monthly and single storm event) and long (annual) time scales when sediment load is highly variable. However, during high streamflow events acoustic surrogate tools may be unable to capture the contribution of suspended sand moving near the bottom of the water column and thus, underestimate the total load of suspended sediment. At the stations where bedload was collected, the particle-size distribution at low streamflows typically was unimodal with sand comprising the dominant particle size. At higher streamflows and during peak bedload discharge, the particle size typically was bimodal and was comprised primarily of sand and coarse gravel. About 55,000 tons of bedload was discharged from the Snake River to Lower Granite Reservoir during water years 2009–11, about 0.62 percent of the total sediment load delivered by the Snake River. About 9,500 tons of bedload was discharged from the Clearwater River to Lower Granite Reservoir during 2009–11, about 0.83 percent of the total sediment load discharged by the Clearwater River during 2009–11.

Estimation of constituent concentrations, densities, loads, and yields in lower Kansas River, northeast Kansas, using regression models and continuous water-quality monitoring, January 2000 through December 2003

USGS Publications Warehouse

Rasmussen, Teresa J.; Ziegler, Andrew C.; Rasmussen, Patrick P.

2005-01-01

The lower Kansas River is an important source of drinking water for hundreds of thousands of people in northeast Kansas. Constituents of concern identified by the Kansas Department of Health and Environment (KDHE) for streams in the lower Kansas River Basin include sulfate, chloride, nutrients, atrazine, bacteria, and sediment. Real-time continuous water-quality monitors were operated at three locations along the lower Kansas River from July 1999 through September 2004 to provide in-stream measurements of specific conductance, pH, water temperature, turbidity, and dissolved oxygen and to estimate concentrations for constituents of concern. Estimates of concentration and densities were combined with streamflow to calculate constituent loads and yields from January 2000 through December 2003. The Wamego monitoring site is located 44 river miles upstream from the Topeka monitoring site, which is 65 river miles upstream from the DeSoto monitoring site, which is 18 river miles upstream from where the Kansas River flows into the Missouri River. Land use in the Kansas River Basin is dominated by grassland and cropland, and streamflow is affected substantially by reservoirs. Water quality at the three monitoring sites varied with hydrologic conditions, season, and proximity to constituent sources. Nutrient and sediment concentrations and bacteria densities were substantially larger during periods of increased streamflow, indicating important contributions from nonpoint sources in the drainage basin. During the study period, pH remained well above the KDHE lower criterion of 6.5 standard units at all sites in all years, but exceeded the upper criterion of 8.5 standard units annually between 2 percent of the time (Wamego in 2001) and 65 percent of the time (DeSoto in 2003). The dissolved oxygen concentration was less than the minimum aquatic-life-support criterion of 5.0 milligrams per liter less than 1 percent of the time at all sites. Dissolved solids, a measure of the dissolved material in water, exceeded 500 milligrams per liter about one-half of the time at the three Kansas River sites. Larger dissolved-solids concentrations upstream likely were a result of water inflow from the highly mineralized Smoky Hill River that is diluted by tributary flow as it moves downstream. Concentrations of total nitrogen and total phosphorus at the three monitoring sites exceeded the ecoregion water-quality criteria suggested by the U.S. Environmental Protection Agency during the entire study period. Median nitrogen and phosphorus concentrations were similar at all three sites, and nutrient load increased moving from the upstream to downstream sites. Total nitrogen and total phosphorus yields were nearly the same from site to site indicating that nutrient sources were evenly distributed throughout the lower Kansas River Basin. About 11 percent of the total nitrogen load and 12 percent of the total phosphorus load at DeSoto during 2000-03 originated from wastewater-treatment facilities. Escherichia coli bacteria densities were largest at the middle site, Topeka. On average, 83 percent of the annual bacteria load at DeSoto during 2000-03 occurred during 10 percent of the time, primarily in conjunction with runoff. The average annual sediment loads at the middle and downstream monitoring sites (Topeka and DeSoto) were nearly double those at the upstream site (Wamego). The average annual sediment yield was largest at Topeka. On average, 64 percent of the annual suspended-sediment load at DeSoto during 2000-03 occurred during 10 percent of the time. Trapping of sediment by reservoirs located on contributing tributaries decreases transport of sediment and sediment-related constituents. The average annual suspended-sediment load in the Kansas River at DeSoto during 2000-03 was estimated at 1.66 million tons. An estimated 13 percent of this load consisted of sand-size particles, so approximately 216,000 tons of sand were transported

Sediment discharge into a subsiding Louisiana deltaic estuary through a Mississippi River diversion

USGS Publications Warehouse

Snedden, G.A.; Cable, J.E.; Swarzenski, C.; Swenson, E.

2007-01-01

Wetlands of the Mississippi River deltaic plain in southeast Louisiana have been hydrologically isolated from the Mississippi River by containment levees for nearly a century. The ensuing lack of fluvial sediment inputs, combined with natural submergence processes, has contributed to high coastal land loss rates. Controlled river diversions have since been constructed to reconnect the marshes of the deltaic plain with the river. This study examines the impact of a pulsed diversion management plan on sediment discharge into the Breton Sound estuary, in which duplicate 185 m3 s-1-diversions lasting two weeks each were conducted in the spring of 2002 and 2003. Sediment delivery during each pulse was highly variable (11,300-43,800 metric tons), and was greatest during rising limbs of Mississippi River flood events. Overland flow, a necessary transport mechanism for river sediments to reach the subsiding backmarsh regions, was induced only when diversion discharge exceeded 100 m3 s-1. These results indicate that timing and magnitude of diversion events are both important factors governing marsh sediment deposition in the receiving basins of river diversions. Though the diversion serves as the primary source of river sediments to the estuary, the inputs observed here were several orders of magnitude less than historical sediment discharge through crevasses and uncontrolled diversions in the region, and are insufficient to offset present rates of relative sea level rise. ?? 2006 Elsevier Ltd. All rights reserved.

Sinks and sources: Assessing microplastic abundance in river sediment and deposit feeders in an Austral temperate urban river system.

PubMed

Nel, Holly A; Dalu, Tatenda; Wasserman, Ryan J

2018-01-15

Microplastics are important novel pollutants in freshwaters but their behaviour in river sediments is poorly understood due to the large amounts of coloured dissolved organic matter that impede sample processing. The present study aimed to 1.) estimate the microplastic pollution dynamics in an urban river system experiencing temporal differences in river flow, and 2.) investigate the potential use of chironomids as indicators of microplastic pollution levels in degraded freshwater environments. Microplastic levels were estimated from sediment and Chironomus spp. larvae collected from various sites along the Bloukrans River system, in the Eastern Cape South Africa during the summer and winter season. River flow, water depth, channel width, substrate embeddedness and sediment organic matter were simultaneously collected from each site. The winter season was characterised by elevated microplastic abundances, likely as a result of lower energy and increased sediment deposition associated with reduced river flow. In addition, results showed that particle distribution may be governed by various other external factors, such as substrate type and sediment organic matter. The study further highlighted that deposit feeders associated with the benthic river habitats, namely Chironomus spp. ingest microplastics and that the seasonal differences in sediment microplastic dynamics were reflected in chironomid microplastic abundance. There was a positive, though weakly significant relationship between deposit feeders and sediment suggesting that deposit feeders such as Chironomus spp. larvae could serve as an important indicator of microplastic loads within freshwater ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

Sediment Transport in Streams in the Umpqua River Basin, Oregon

USGS Publications Warehouse

Onions, C. A.

1969-01-01

This report presents tables of suspended-sediment data collected from 1956 to 1967 at 10 sites in the Umpqua River basin. Computations based on these data indicate that average annual suspended-sediment yields at these sites range from 137 to 822 tons per square mile. Because available data for the Umpqua River basin are generally inadequate for accurate determinations of sediment yield and for the definition of characteristics of fluvial sediments, recommendations are made for the collection and analysis of additional sediment data.

An Integrated Assessment of Sediment Remediation in a Midwestern U.S. Stream Using Sediment Chemistry, Water Quality, Bioassessment and Fish Biomarkers

EPA Science Inventory

A comprehensive biological, sediment and water quality study of the lower Little Scioto River near Marion, Ohio, USA was undertaken in July 2007 to evaluate the effectiveness of removal of creosote-contaminated sediment. The study area covered 7.5 river miles (RMs) of the river, ...

(210)Pb and composition data of near-surface sediments and interstitial waters evidencing anthropogenic inputs in Amazon River mouth, Macapá, Brazil.

PubMed

Nery, José Reinaldo Cardoso; Bonotto, Daniel Marcos

2011-04-01

Activity profiles of excess (210)Pb determined in three sediment cores from Amazon River mouth, Macapá city, Brazil, provided the evaluation of sedimentation rates, contributing to a better knowledge of the hydrological conditions in the site that is the capital of Amapá State and is drained by the waters of the huge Amazon River. Chemical data were also determined in the sediments, allowing identify signatures coupled to anthropogenic inputs held in the past in Amapá State. Significant direct relationships between LOI (loss on ignition) and organic matter were found for all sediments profiles. Silica was found to be inversely related to organic matter in the three profiles; its decrease accompanied an increase on the specific surface of the sediments. This relationship was confirmed by a great number of inverse significant correlations among silica and oxides Na(2)O, K(2)O, CaO, MgO, Al(2)O(3), P(2)O(5), Fe(2)O(3) and MnO. It was possible to identify the role of organic matter on adsorption of several oxides in the core sediments profiles. Apparent sediment mass accumulation rates corresponding to values between 450 and 2510 mg cm(-2)yr(-1) were obtained, and are compatible with the results of others studies. The (210)Pb activities in one sampling point suggested the occurrence of anthropogenic inputs related to the initial period of the mining activities conducted in Serra do Navio, Amapá State, for the commercialization of Mn ores. This was reinforced by the abrupt fluctuations in chemical data obtained for the sediments and composition of the interstitial waters occurring there. The Atlantic hurricane activity also appeared to affect the sedimentation rates in the area, as two different values were recorded in each profile. Copyright © 2011 Elsevier Ltd. All rights reserved.

Sediment load and distribution in the lower Skagit River, Skagit County, Washington

USGS Publications Warehouse

Curran, Christopher A.; Grossman, Eric E.; Mastin, Mark C.; Huffman, Raegan L.

2016-08-17

The Skagit River delivers about 40 percent of all fluvial sediment that enters Puget Sound, influencing flood hazards in the Skagit lowlands, critically important estuarine habitat in the delta, and some of the most diverse and productive agriculture in western Washington. A total of 175 measurements of suspended-sediment load, made routinely from 1974 to 1993, and sporadically from 2006 to 2009, were used to develop and evaluate regression models of sediment transport (also known as “sediment-rating curves”) for estimating suspended-sediment load as a function of river discharge. Using a flow-range model and 75 years of daily discharge record (acquired from 1941 to 2015), the mean annual suspended-sediment load for the Skagit River near Mount Vernon, Washington, was estimated to be 2.5 teragrams (Tg, where 1 Tg = 1 million metric tons). The seasonal model indicates that 74 percent of the total annual suspended‑sediment load is delivered to Puget Sound during the winter storm season (from October through March), but also indicates that discharge is a poor surrogate for suspended‑sediment concentration (SSC) during the summer low-flow season. Sediment-rating curves developed for different time periods revealed that the regression model slope of the SSC-discharge relation increased 66 percent between the periods of 1974–76 and 2006–09 when suspended-sediment samples were collected, implying that changes in sediment supply, channel hydraulics, and (or) basin hydrology occurred between the two time intervals. In the relatively wet water year 2007 (October 1, 2006, through September 30, 2007), an automated sampler was used to collect daily samples of suspended sediment from which an annual load of 4.5 Tg was calculated, dominated by a single large flood event that contributed 1.8 Tg, or 40 percent of the total. In comparison, the annual load calculated for water year 2007 using the preferred flow-range model was 4.8 Tg (+6.7 percent), in close agreement with the measured value.Particle size affects sediment transport, fate and distribution across watersheds, and therefore is important for predicting how coastal environments, particularly deltas and beaches, will respond to changes in climate and sea-level. Particle-size analysis of winter storm samples indicated that about one-half of the suspended-sediment load consisted of fines (that is, silt- and clay-sized particles smaller than 0.0625 mm in diameter), and the remainder consisted of mostly fine- to medium-sized sand (0.0625–0.5 mm), whereas bedload during winter storm flows (about 1–3 percent of total sediment load) was predominantly composed of medium to coarse sand (0.25–1 mm). A continuous turbidity record from the Anacortes Water Treatment Plant (water years 1999–2013), used as a surrogate for the concentration of fines (R2 = 0.93, p = 4.2E-10, n = 17), confirms that about one-half of the mean annual suspended-sediment load is composed of fines.The distribution of flow through the delta distributaries (that is, the channels into which the main stem splits as it approaches the delta) is dynamic, with twice as much flow through the North Fork of the Skagit River relative to the South Fork during low-flow conditions, and close to equal flows in the two channels during high-flow conditions. Turbidity, monitored at several locations in the lower river in spring 2009, was essentially uniform among sites, indicating that fines are well mixed in the lower Skagit River system (defined as the Skagit River and all its distributaries downstream of the Mount Vernon streamgage). A strong relation (R2 = 0.95, p = 3.2E-14, n = 21; linear regression) between the concentration of fines and turbidity measured at various locations in summer 2009 indicates that turbidity is an effective surrogate for the concentration of fines, independent of location in the river, under naturally well-mixed fluvial conditions. This relation is especially useful for monitoring suspended sediment in western Washington rivers that are seasonally dominated by glacier meltwater because glacial melting typically produces suspended-sediment concentrations that are not well correlated with discharge. These results provide a comprehensive set of tools to estimate sediment delivery and delta responses of interest to scientists and resource managers including decision-makers examining options for flood hazard mitigation, estuary restoration, and climate change adaptation.

The Detroit River: Effects of contaminants and human activities on aquatic plants and animals and their habitats

USGS Publications Warehouse

Manny, Bruce A.; Kenaga, David

1991-01-01

Despite the extensive urbanization of its watershed, the Detroit River still supports diverse fish and wildlife populations. Conflicting uses of the river for waste disposal, water withdrawals, shipping, recreation, and fishing require innovative management. Chemicals added by man to the Detroit River have adversely affected the health and habitats of the river's plants and animals. In 1985, as part of an Upper Great Lakes Connecting Channels Study sponsored by Environment Canada and the U.S. Environmental Protection Agency, researchers exposed healthy bacteria, plankton, benthic macroinvertebrates, fish, and birds to Detroit River sediments and sediment porewater. Negative impacts included genetic mutations in bacteria; death of macroinvertebrates; accumulation of contaminants in insects, clams, fish, and ducks; and tumor formation in fish. Field surveys showed areas of the river bottom that were otherwise suitable for habitation by a variety of plants and animals were contaminated with chlorinated hydrocarbons and heavy metals and occupied only by pollution-tolerant worms. Destruction of shoreline wetlands and disposal of sewage and toxic substances in the Detroit River have reduced habitat and conflict with basic biological processes, including the sustained production of fish and wildlife. Current regulations do not adequately control pollution loadings. However, remedial actions are being formulated by the U.S. and Canada to restore degraded benthic habitats and eliminate discharges of toxic contaminants into the Detroit River.

Dating of coastal marine sediments: 210Pb versus 137Cs signal on the Danube-influenced Black Sea shelf

NASA Astrophysics Data System (ADS)

Friedrich, Jana; Laptev, Gennady

2010-05-01

Coastal marine sediments represent a natural archive of pelagic processes, coastal erosion and river discharge of suspended matter. Correct dating of those sediments is a prerequisite for chronological reconstruction of the flux of pollutants and organic matter from the water column to the sediments and hence, the reconstruction of the pollution and eutrophication events. In the reconstruction of the sedimentation history during the pre-industrial and industrial periods, which usually spans the past 100 years, the natural occurring radionuclide 210Pb and the artificial radionuclides 137Cs and 241Am are widely applied tracers. 137Cs is used as an independent time marker for end the atmospheric bomb test fallout in 1963 and the Chernobyl accident in 1986. As the 137Cs signal is often weakened due to its mobility in sediments, 241Am, less mobile than 137Cs and derived from decay the bomb fallout of 241Pu, is used as a second time marker of the 1963 event. The northwestern shelf of the Black Sea has been seriously affected by eutrophication and pollution from the late 1960's to the mid-1990's, largely triggered by Danube River input of nutrients and pollutants. The aim of our study is ultimately to reconstruct the eutrophication history and recycling of nutrients following the deposition of organic matter. The ‘memory effect' of sediment recycling plays a critical role in maintaining eutrophic conditions in enclosed seas such as the Black Sea. Here we present results from sediment cores taken within the Danube River plume on the shallow northwestern shelf of the Black Sea. The cores have been dated in two laboratories to rule out artifacts. The sediment record is repeatedly interrupted by so-called turbidites that consist of stiff clay. The clay horizons display a drop in unsupported 210Pb and 137Cs and a higher signal of supported 210Pb than the non-clay horizons. Below the turbidite, the unsupported 210Pb and 137Cs increase again to values above the turbidite. This points to a non-marine origin of the turbidite. In such sediment sequence, the classical application of the CRS model would provide false ages and sedimentation rates. We hypothesize that the turbidite represents terrestrial clay eroded from the Danube Delta that had been transported in pulse-like events during flash floods of the Danube River.

Substantial export of suspended sediment to the global oceans from glacial erosion in Greenland

NASA Astrophysics Data System (ADS)

Overeem, I.; Hudson, B. D.; Syvitski, J. P. M.; Mikkelsen, A. B.; Hasholt, B.; van den Broeke, M. R.; Noël, B. P. Y.; Morlighem, M.

2017-11-01

Limited measurements along Greenland's remote coastline hamper quantification of the sediment and associated nutrients draining the Greenland ice sheet, despite the potential influence of river-transported suspended sediment on phytoplankton blooms and carbon sequestration. Here we calibrate satellite imagery to estimate suspended sediment concentration for 160 proglacial rivers across Greenland. Combining these suspended sediment reconstructions with numerical calculations of meltwater runoff, we quantify the amount and spatial pattern of sediment export from the ice sheet. We find that, although runoff from Greenland represents only 1.1% of the Earth's freshwater flux, the Greenland ice sheet produces approximately 8% of the modern fluvial export of suspended sediment to the global ocean. Sediment loads are highly variable between rivers, consistent with observed differences in ice dynamics and thus with control by glacial erosion. Rivers that originate from deeply incised, fast-moving glacial tongues form distinct sediment-export hotspots: just 15% of Greenland's rivers transport 80% of the total sediment load of the ice sheet. We conclude that future acceleration of melt and ice sheet flow may increase sediment delivery from Greenland to its fjords and the nearby ocean.

Sediment accumulation rates and high-resolution stratigraphy of recent fluvial suspension deposits in various fluvial settings, Morava River catchment area, Czech Republic

NASA Astrophysics Data System (ADS)

Sedláček, Jan; Bábek, Ondřej; Kielar, Ondřej

2016-02-01

We present a comprehensive study concerning sedimentary processes in fluvial sediment traps within the Morava River catchment area (Czech Republic) involving three dammed reservoirs, four meanders and oxbow lakes, and several natural floodplain sites. The objective of the study was to determine sediment accumulation rates (SAR), estimate erosion rates, calculating these using a combination of the 137Cs method and historical data. Another purpose of this study was to provide insight into changing erosion and accumulation rates over the last century. Extensive water course modifications were carried out in the Morava River catchment area during the twentieth century, which likely affected sedimentation rates along the river course. Other multiproxy stratigraphic methods (X-ray densitometry, magnetic susceptibility, and visible-light reflectance spectrometry) were applied to obtain additional information about sediment infill. Sediment stratigraphy revealed distinct distal-to-proximal patterns, especially in reservoirs. Granulometrically, silts and sandy silts prevailed in sediments. Oxbow lakes and meanders contained larger amounts of clay and organic matter, which is the main difference between them and reservoirs. Pronounced 137Cs peaks were recorded in all studied cores (maximum 377 Bq·kg- 1), thus indicating Chernobyl fallout from 1986 or older events. Calculated sediment accumulation rates were lowest in distal parts of reservoirs (0.13-0.58 cm/y) and floodplains (0.45-0.88 cm/y), moderately high rates were found in proximal parts of reservoirs and oxbow lakes (2.27-4.4 cm/y), and the highest rates in some oxbow lakes located near the river (6-8 cm/y). The frequency of the inundation still can be high in some natural areas as in the Litovelské Pomoraví protected area, whereas the decreasing frequency of the inundation in other modified parts can contribute to a lower sedimentation rate. The local effects such as difference between SARs in oxbow lakes and reservoirs, different grain size distribution in both systems, and high variability in thickness of their proximal and distal parts play a crucial role in the analysis of regional accumulation rates. Local effects are much stronger than regional effects, such as rainfall and land use. Combined with the low resolution of time scales (usually only three datums are available: reservoir construction datum, 137Cs fallout event, and top of sediment), these effects may obscure the general trends of regionally increasing or decreasing net SARs, making the analysis of erosion rates from the sedimentary record an extremely difficult task.

Immobilization of U(VI) from Oxic Groundwater by Hanford 300 Area Sediments and Effects of Columbia River Water

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

Ahmed, B.; Cao, Bin; Mishra, Bhoopesh

2012-09-23

Regions within the U.S. Department of Energy Hanford 300 Area (300 A) site experience periodic hydrologic influences from the nearby Columbia River as a result of changing river stage, which causes changes in groundwater elevation, flow direction and water chemistry. An important question is the extent to which the mixing of Columbia River water and groundwater impacts the speciation and mobility of uranium (U). In this study, we designed experiments to mimic interactions among U, oxic groundwater or Columbia River water, and 300 A sediments in the subsurface environment of Hanford 300 A. The goals were to investigate mechanisms of:more » 1) U immobilization in 300 A sediments under bulk oxic conditions and 2) U remobilization from U-immobilized 300 A sediments exposed to oxic Columbia River water. Initially, 300 A sediments in column reactors were fed with U(VI)-containing oxic 1) synthetic groundwater (SGW), 2) organic-amended SGW (OA-SGW), and 3) de-ionized (DI) water to investigate U immobilization processes. After that, the sediments were exposed to oxic Columbia River water for U remobilization studies. The results reveal that U was immobilized by 300 A sediments predominantly through reduction (80-85%) when the column reactor was fed with oxic OA-SGW. However, U was immobilized by 300 A sediments through adsorption (100%) when the column reactors were fed with oxic SGW or DI water. The reduced U in the 300 A sediments fed with OA-SGW was relatively resistant to remobilization by oxic Columbia River water. Oxic Columbia River water resulted in U remobilization (~7%) through desorption, and most of the U that remained in the 300 A sediments fed with OA-SGW (~93%) was in the form of uraninite nanoparticles. These results reveal that: 1) the reductive immobilization of U through OA-SGW stimulation of indigenous 300 A sediment microorganisms may be viable in the relatively oxic Hanford 300 A subsurface environments and 2) with the intrusion of Columbia River water, desorption may be the primary process resulting in U remobilization from OA-SGW-stimulated 300 A sediments at the subsurface of the Hanford 300 A site.« less

Tracking sediment through the Holocene: Determining anthropogenic contributions to a sediment-rich agricultural system, north-central USA

NASA Astrophysics Data System (ADS)

Gran, Karen; Belmont, Patrick; Finnegan, Noah

2013-04-01

Management and restoration of sediment-impaired streams requires quantification of sediment sources and pathways of transport. Addressing the role of humans in altering the magnitude and sources of sediment supplied to a catchment is notoriously challenging. Here, we explore how humans have amplified erosion in geomorphically-sensitive portions of the predominantly-agricultural Minnesota River basin in north-central USA. In the Minnesota River basin, the primary sources of sediment are classified generally as upland agricultural field vs. near-channel sources, with near-channel sources including stream banks, bluffs, and ravines. Using aerial lidar data, repeat terrestrial lidar scans of bluffs, ravine monitoring, historic air photo analyses, and sediment fingerprinting, we have developed a sediment budget to determine the relative importance of each source in a tributary to the Minnesota River, the Le Sueur River. We then investigate how these sources have changed through time, from changes evident over the past few decades to changes associated with valley evolution over the past 13,400 years. The Minnesota River valley was carved ~13,400 years ago through catastrophic drainage of glacial Lake Agassiz. As the Minnesota River valley incised, knickpoints have migrated upstream into tributaries, carving out deep valleys where the most actively eroding near-channel sediment sources occur. The modern sediment budget, closed for the time period 2000 to 2010, shows that the majority of the fine sediment load in the Le Sueur River comes from bluffs and other near-channel sources in the deeply-incised knick zone. Numerical modeling of valley evolution constrained by mapped and dated strath terraces cut into the glacial till presents an opportunity to compare the modern sediment budget to that of the river prior to anthropogenic modification. This comparison reveals a natural background or "pre-agriculture" rate of erosion from near-channel sources to be 3-5 times lower than modern near-channel erosion rates. Notably, depositional records from a naturally-dammed lake downstream on the upper Mississippi River show a more dramatic 10-fold increase in deposition rates from pre-agricultural times to the present. Sediment fingerprinting shows that pre-agriculture sediment loads were dominated by near-channel sediment sources. As deposition rates rose in the late 1800s and early 1900s, the sources shifted increasingly to agricultural soil erosion. In the past few decades, deposition rates have remained high, but sediment fingerprinting indicates yet another significant shift back to near-channel sources. On-going changes in basin hydrology, from both installation of agricultural drainage systems and on-going climate change have put more water in the rivers, increasing rates of near-channel bank and bluff erosion. This most recent shift in sediment sources has significant implications for turbidity management in the Minnesota River basin.

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

USGS Publications Warehouse

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

2009-01-01

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

Water-quality assessment of the lower Illinois River Basin; environmental setting

USGS Publications Warehouse

Warner, Kelly L.

1998-01-01

The lower Illinois River Basin (LIRB) encompasses 18,000 square miles of central and western Illinois. Historical and recent information from Federal, State, and local agencies describing the physiography, population, land use, soils, climate, geology, streamflow, habitat, ground water, water use, and aquatic biology is summarized to describe the environmental setting of the LIRB. The LIRB is in the Till Plains Section of the Central Lowland physiographic province. The basin is characterized by flat topography, which is dissected by the Illinois River. The drainage pattern of the LIRB has been shaped by many bedrock and glacial geologic processes. Erosion prior to and during Pleistocene time created wide and deep bedrock valleys. The thickest deposits and most major aquifers are in buried bedrock valleys. The Wisconsinan glaciation, which bisects the northern half of the LIRB, affects the distribution and characteristics of glacial deposits in the basin. Agriculture is the largest land use and forested land is the second largest land use in the LIRB. The major urban areas are near Peoria, Springfield, Decatur, and Bloomington-Normal. Soil type and distribution affect the amount of soil erosion, which results in sedimentation of lakes and reservoirs in the basin. Rates of soil erosion of up to 2 percent per year of farmland soil have been measured. Many of the 300 reservoirs, lakes, and wetlands are disappearing because of sedimentation resulting from agriculture activities, levee building, and urbanization. Sedimentation and the destruction of habitat appreciably affect the ecosystem. The Illinois River is a large river-floodplain ecosystem where biological productivity is enhanced by annual flood pulses that advance and retreat over the flood plain and temporarily expand backwater and flood-plain lakes. Ground-water discharge to streams affects the flow and water quality of the streams. The water budget of several subbasins show variability in ground-water contribution from runoff and storage. More than half of the drinking water, including domestic and public-supply use, in the LIRB is from ground water. Fifty-two percent of the public-supply water is from surface water. Ground-water withdrawals mostly are from glacial sand and gravel aquifers. Structural features, such as monoclines, synclines, and anticlines, in the buried bedrock affect the water quality of the aquifers. There are five natural environmental divisions in the LIRB. The Grand Prairie covers most of the northeastern half of the basin, and the Western Forest-Prairie covers most of the southwestern half. Implications of environmental setting for water quality in the LIRB are related primarily to land use. The balanced fish community indicates that the lower Illinois River is affected less from urban and industrial waste than the upper Illinois River. A decrease in dissolved oxygen concentrations and turbidity in the lower reaches of the basin in 1993 have resulted from the recent influx of European zebra mussels to the LIRB. Many factors affect water quality in the LIRB. Bedrock and surface topography, type of glacial material, and land use most directly affect water quality in the basin.

Sources of sediment to the coastal waters of the Southern California Bight

USGS Publications Warehouse

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

2009-01-01

The sources of sediment to the Southern California Bight were investigated with new calculations and published records of sediment fluxes, both natural and anthropogenic. We find that rivers are by far the largest source of sediment, producing over 10 ?? 106 t/yr on average, or over 80% of the sediment input to the Bight. This river flux is variable, however, over both space and time. The rivers draining the Transverse Ranges produce sediment at rates approximately an order of magnitude greater than the Peninsular Ranges (600-1500 t/km2/yr versus <90 t/km2/yr, respectively). Although the Transverse Range rivers represent only 23% of the total Southern California watershed drainage area, they are responsible for over 75% of the total sediment flux. River sediment flux is ephemeral and highly pulsed due to the semiarid climate and the influence of infrequent large storms. For more than 90% of the time, negligible amounts of sediment are discharged from the region's rivers, and over half of the post-1900 sediment load has been discharged during events with recurrence intervals greater than 10 yr. These rare, yet important, events are related to the El Ni??o-Southern Oscillation (ENSO), and the majority of sediment flux occurs during ENSO periods. Temporal trends in sediment discharge due to land-use changes and river damming are also observed. We estimate that there has been a 45% reduction in suspended-sediment flux due to the construction of dams. However, pre-dam sediment loads were likely artificially high due to the massive land-use changes of coastal California to rangeland during the nineteenth century. This increase in sediment production is observed in estuarine deposits throughout coastal California, which reveal that sedimentation rates were two to ten times higher during the nineteenth and twentieth centuries than during pre-European colonization. ?? 2009 The Geological Society of America.

Flow and sediment dynamics in the vegetated secondary channels of an anabranching river: The Loire River (France)

NASA Astrophysics Data System (ADS)

Rodrigues, Stéphane; Bréhéret, Jean-Gabriel; Macaire, Jean-Jacques; Moatar, Florentina; Nistoran, Dana; Jugé, Philippe

2006-04-01

This study investigates the hydrological and sedimentological mechanisms occurring in the vegetated secondary channels of an anabranching river affected by incision: the Loire River (France). During and after flood events that occurred between 2000 and 2003, observations and measurements were performed on a vegetated secondary channel located in the study site of Bréhémont (790 km downstream the source). Morphological changes and sediment dynamics were analysed using low elevation airborne photographs, topographic and bathymetric surveys, and scour chains. The hydraulic behaviour of the channel was also analysed by measurements performed on flow velocity and direction during different flood stages. In order to quantify the influence of woody vegetation on flow resistance, the roughness of bands of trees was determined from measurements performed on the field. The impact of the disruption of armour layers on bedload pulses, the variation of sedimentary processes during a single flood event and the fixation of bedforms by vegetation are all identified as key processes influencing the behaviour of the study channel. Topographic surveys demonstrate that sediment dynamics is substantial in the upstream part of the channel and that sediment budgets are different according to the temporal scale considered. Moreover, an asymmetrical behaviour of the secondary channel is demonstrated: reduced quantities of sediment deposited and preserved in the vegetated zones contrast with material by-passing observed in the third order channels. Flow velocity and direction measurements indicate that these parameters vary according to the water level and to the morphological units of the channel (pools, riffles, vegetated areas). During low flows, scouring and export of particles from the secondary channel are a consequence of reduced sediment supply from the main channel of the Loire River. For these water levels, sedimentation occurs in pools where velocity and turbulence decrease whereas third order channels are subjected to erosion. During high discharges, large quantities of sediment available in the main channel feed the temporary stores formed by riffles and bars in the secondary channel. The vegetated area located in the downstream part of the secondary channel deflects current trickles at low discharges and decreases flow velocity during high water levels. The sedimentary accretion observed in this area exerts a feedback on flow and sedimentary processes.

Characteristics of sediment discharge in the subarctic Yukon River, Alaska

USGS Publications Warehouse

Chikita, K.A.; Kemnitz, R.; Kumai, R.

2002-01-01

The characteristics of sediment discharge in the Yukon River, Alaska were investigated by monitoring water discharge, water turbidity and water temperature. The river-transported sediment, 90 wt.% or more, consists of silt and clay (grain size ??? 62.5 ??m), which probably originated in the glacier-covered mountains mostly in the Alaska Range. For early June to late August 1999, we continuously measured water turbidity and temperature near the estuary and in the middle of Yukon River by using self-recording turbidimeters and temperature data loggers. The water turbidity (ppm) was converted to suspended sediment concentration (SSC; mg/l) of river water, using a relation between simultaneous turbidity and SSC at each of the two sites, and then, the suspended sediment discharge, approximately equal to water discharge times SSC, was numerically obtained every 1 or 2 h. It should be noted that the sediment discharge in the Yukon River is controlled by SSC rather than water discharge. As a result, a peak sediment discharge occurred in mid or late August by local sediment runoffs due to glacier-melt (or glacier-melt plus rainfall), while a peak water discharge was produced by snowmelt in late June or early July. Application of the "extended Shields diagram" indicates that almost all the river-transported sediments are under complete suspension. ?? 2002 Elsevier Science B.V. All rights reserved.

Origin and depositional environment of fine-grained sediments since the last glacial maximum in the southeastern Yellow Sea: evidence from rare earth elements

NASA Astrophysics Data System (ADS)

Um, In Kwon; Choi, Man Sik; Lee, Gwang Soo; Chang, Tae Soo

2015-12-01

Despite the well-reconstructed seismic stratigraphy of the Holocene mud deposit in the southeastern Yellow Sea, known as the Heuksan mud belt (HMB), the provenances of these sediments and their depositional environments are unclear, especially for the fine-grained sediments. According to seismic data (extracted from another article in this special issue), the HMB comprises several sedimentary units deposited since the last glacial maximum. Based on analytical results on rare earth elements, fine-grained sediments in all sedimentary units can be interpreted as mixtures of sediments discharged from Chinese and Korean rivers. The proportions of fine-grained sediments from Chinese rivers (74.5 to 80.0%) were constant and higher than those from Korean rivers in all units. This fact demonstrates that all units have the same fine-grained sediment provenance: units III-b and III-a, located in the middle and northern parts of the HMB and directly deposited from Chinese rivers during the sea-level lowstand, could be the sediment source for units II-b and II-a. Unit I, while ambiguous, is of mixed origin combining reworked sediments from nearby mud deposits and Changjiang River-borne material with those of the Keum River. The results of this study indicate that at least 18.6% of bulk sediments in the HMB clearly originate from Chinese rivers, despite its location close to the southwestern coast of Korea.

Historical changes in organic matter input to the muddy sediments along the Zhejiang-Fujian Coast, China over the past 160 years

USGS Publications Warehouse

Chen, Li-lei; Liu, Jian; Xing, Lei; Krauss, Ken W.; Wang, Jia-sheng; Xu, Gang; Li, Li

2017-01-01

The burial of sedimentary organic matter (SOM) in the large river-influenced estuarine-coastal regions is affected by hydrodynamic sorting, diagenesis and human activities. Typically, the inner shelf region of the East China Sea is a major carbon sink of the Yangtze River-derived fine-grained sediments. Most of the previous work concentrated on the studies of surface sediments or used a single-proxy in this region. In this study, two cores from the Zhejiang-Fujian Coast were analyzed using bulk (TOC, TN and δ13CTOC) and molecular biomarker (n-alkane, brassicasterol, dinosterol and glycerol dialkyl glycerol tetraether lipids) techniques to clarify the sources, spatiotemporal distribution and fate of SOM in the Yangtze River Estuary and adjacent shelf. Results from this study indicated that the effects of diagenesis and diffusion on different sedimentary biomarkers resulted in overestimation of the relative contribution of terrestrial organic matter (%OMterr), compared with those based on δ13CTOC. The amounts of terrestrial plant organic matter (OMplant) and%OMterr in sediments decreased offshore. In contrast, the amounts of marine organic matter (OMmarine) increased offshore, but closer to the Yangtze River mouth, the amounts of soil organic matter (OMsoil) increased. Moreover, the amounts of TOC, OMplant and OMmarine biomarkers increased, but OMsoil and%OMterrdecreased over time in recent decades. Our study suggests that spatial organic matter distribution patterns in marine shelf sediments were controlled primarily by hydrodynamic sorting and nutrient concentrations, and temporally diverse patterns were controlled predominantly by anthropogenic influence (e.g., dam construction and soil conservation, reclamation and agricultural plantations, anthropogenic nutrient input, dust storms, eutrophication, etc) and climate events (e.g., interdecadal climatic jump and heavy rain events) in the geological period.

Implication of two in-stream processes in the fate of nutrients discharged by sewage system into a temporary river.

PubMed

David, Arthur; Perrin, Jean-Louis; Rosain, David; Rodier, Claire; Picot, Bernadette; Tournoud, Marie-George

2011-10-01

The aim of this study was to better understand the fate of nutrients discharged by sewage treatment plants into an intermittent Mediterranean river, during a low-flow period. Many pollutants stored in the riverbed during the low-flow period can be transferred to the downstream environments during flood events. The study focused on two processes that affect the fate and the transport of nutrients, a physical process (retention in the riverbed sediments) and a biological process (denitrification). A spatial campaign was carried out during a low-flow period to characterize the nutrient contents of both water and sediments in the Vène River. The results showed high nutrient concentrations in the water column downstream of the treated wastewater disposal (up to 13,315 μg N/L for ammonium and 2,901 μg P/L for total phosphorus). Nutrient concentrations decreased rapidly downstream of the disposal whereas nutrient contents in the sediments increased (up to 1,898 and 784 μg/g for total phosphorus and Kjeldahl nitrogen, respectively). According to an in situ experiment using sediment boxes placed in the riverbed for 85 days, we estimated that the proportion of nutrients trapped in the sediments represents 25% (respectively 10%) of phosphorus (respectively nitrogen) loads lost from the water column. In parallel, laboratory tests indicated that denitrification occurred in the Vène River, and we estimated that denitrification likely coupled to nitrification processes during the 85 days of the experiment was significantly involved in the removal of nitrogen loads (up to 38%) from the water column and was greater than accumulation processes.

Floodplain geomorphic processes and environmental impacts of human alteration along coastal plain rivers, USA

USGS Publications Warehouse

Hupp, C.R.; Pierce, Aaron R.; Noe, G.B.

2009-01-01

Human alterations along stream channels and within catchments have affected fluvial geomorphic processes worldwide. Typically these alterations reduce the ecosystem services that functioning floodplains provide; in this paper we are concerned with the sediment and associated material trapping service. Similarly, these alterations may negatively impact the natural ecology of floodplains through reductions in suitable habitats, biodiversity, and nutrient cycling. Dams, stream channelization, and levee/canal construction are common human alterations along Coastal Plain fluvial systems. We use three case studies to illustrate these alterations and their impacts on floodplain geomorphic and ecological processes. They include: 1) dams along the lower Roanoke River, North Carolina, 2) stream channelization in west Tennessee, and 3) multiple impacts including canal and artificial levee construction in the central Atchafalaya Basin, Louisiana. Human alterations typically shift affected streams away from natural dynamic equilibrium where net sediment deposition is, approximately, in balance with net erosion. Identification and understanding of critical fluvial parameters (e.g., stream gradient, grain-size, and hydrography) and spatial and temporal sediment deposition/erosion process trajectories should facilitate management efforts to retain and/or regain important ecosystem services. ?? 2009, The Society of Wetland Scientists.

Assessment of total bed material equations on selected Malaysia rivers

NASA Astrophysics Data System (ADS)

Saleh, A.; Abustan, I.; Mohd Remy Rozainy, M. A. Z.; Sabtu, N.

2017-10-01

Assessment of total sediment load equations on selected Malaysia rivers was done based on 35 sediment loads and hydraulic data. Four rivers were selected to make this assessment which are Sungai Perak, Sungai Kemaman, Sungai Pergau and Sungai Kurau. These rivers can be divided into three categories based on the river width, with Sungai Perak (300-350m) and Sungai Kemaman (150-200m) can categorised as big rivers, meanwhile, Sungai Pergau (30-45m) and Sungai Kurau (10-11m) can categorised as medium and small river respectively. The total sediment load equations used in this assessment are Ackers-White, Brownlie, Engelund-Hansen, Graf, Molinas-Wu, Karim-Kennedy and Yang. This paper also tested the local total sediment load equations by Ariffin and Sinnakaudan et al. to evaluate capabilities of the equations on different rivers in Malaysia. The graphs of the calculated equations versus measured sediment transport rates were plotted to shows the accuracy of the tested equations.

Sediment Transport Dynamic in a Meandering Fluvial System: Case Study of Chini River

NASA Astrophysics Data System (ADS)

Nazir, M. H. M.; Awang, S.; Shaaban, A. J.; Yahaya, N. K. E. M.; Jusoh, A. M.; Arumugam, M. A. R. M. A.; Ghani, A. A.

2016-07-01

Sedimentation in river reduces the flood carrying capacity which lead to the increasing of inundation area in the river basin. Basic sediment transport can predict the fluvial processes in natural rivers and stream through modeling approaches. However, the sediment transport dynamic in a small meandering and low-lying fluvial system is considered scarce in Malaysia. The aim of this study was to analyze the current riverbed erosion and sedimentation scenarios along the Chini River, Pekan, Pahang. The present study revealed that silt and clay has potentially been eroded several parts of the river. Sinuosity index (1.98) indicates that Chini River is very unstable and continuous erosion process in waterways has increase the riverbank instability due to the meandering factors. The riverbed erosional and depositional process in the Chini River is a sluggish process since the lake reduces the flow velocity and causes the deposited particles into the silt and clay soil at the bed of the lake. Besides, the bed layer of the lake comprised of cohesive silt and clayey composition that tend to attach the larger grain size of sediment. The present study estimated the total sediment accumulated along the Chini River is 1.72 ton. The HEC-RAS was employed in the simulations and in general the model performed well, once all parameters were set within their effective ranges.

Numerical Modeling of Large-Scale Rocky Coastline Evolution

NASA Astrophysics Data System (ADS)

Limber, P.; Murray, A. B.; Littlewood, R.; Valvo, L.

2008-12-01

Seventy-five percent of the world's ocean coastline is rocky. On large scales (i.e. greater than a kilometer), many intertwined processes drive rocky coastline evolution, including coastal erosion and sediment transport, tectonics, antecedent topography, and variations in sea cliff lithology. In areas such as California, an additional aspect of rocky coastline evolution involves submarine canyons that cut across the continental shelf and extend into the nearshore zone. These types of canyons intercept alongshore sediment transport and flush sand to abyssal depths during periodic turbidity currents, thereby delineating coastal sediment transport pathways and affecting shoreline evolution over large spatial and time scales. How tectonic, sediment transport, and canyon processes interact with inherited topographic and lithologic settings to shape rocky coastlines remains an unanswered, and largely unexplored, question. We will present numerical model results of rocky coastline evolution that starts with an immature fractal coastline. The initial shape is modified by headland erosion, wave-driven alongshore sediment transport, and submarine canyon placement. Our previous model results have shown that, as expected, an initial sediment-free irregularly shaped rocky coastline with homogeneous lithology will undergo smoothing in response to wave attack; headlands erode and mobile sediment is swept into bays, forming isolated pocket beaches. As this diffusive process continues, pocket beaches coalesce, and a continuous sediment transport pathway results. However, when a randomly placed submarine canyon is introduced to the system as a sediment sink, the end results are wholly different: sediment cover is reduced, which in turn increases weathering and erosion rates and causes the entire shoreline to move landward more rapidly. The canyon's alongshore position also affects coastline morphology. When placed offshore of a headland, the submarine canyon captures local sediment, increases weathering and erosion around the headland, and eventually changes the headland into an embayment! Improvements to our modeling approach include refining the initial conditions. To create a fractal, immature rocky coastline, self-similar river networks with random side branches were drawn on the shoreline domain. River networks and side branches were scaled according to Horton's law and Tokunaga statistics, respectively, and each river pathway was assigned a simple exponential longitudinal profile. Topography was generated around the river networks to create drainage basins and, on a larger scale, represent a mountainous, fluvially-sculpted landscape. The resultant morphology was then flooded to a given elevation, leaving a fractal rocky coastline. In addition to the simulated terrain, actual digital elevation models will also be used to derive the initial conditions. Elevation data from different mountainous geomorphic settings such as the decaying Appalachian Mountains or actively uplifting Sierra Nevada can be effectively flooded to a given sea level, resulting in a fractal and immature coastline that can be input to the numerical model. This approach will offer insight into how rocky coastlines in different geomorphic settings evolve, and provide a useful complement to results using the simulated terrain.

Multivariate analysis of heavy metal contamination using river sediment cores of Nankan River, northern Taiwan

NASA Astrophysics Data System (ADS)

Lee, An-Sheng; Lu, Wei-Li; Huang, Jyh-Jaan; Chang, Queenie; Wei, Kuo-Yen; Lin, Chin-Jung; Liou, Sofia Ya Hsuan

2016-04-01

Through the geology and climate characteristic in Taiwan, generally rivers carry a lot of suspended particles. After these particles settled, they become sediments which are good sorbent for heavy metals in river system. Consequently, sediments can be found recording contamination footprint at low flow energy region, such as estuary. Seven sediment cores were collected along Nankan River, northern Taiwan, which is seriously contaminated by factory, household and agriculture input. Physico-chemical properties of these cores were derived from Itrax-XRF Core Scanner and grain size analysis. In order to interpret these complex data matrices, the multivariate statistical techniques (cluster analysis, factor analysis and discriminant analysis) were introduced to this study. Through the statistical determination, the result indicates four types of sediment. One of them represents contamination event which shows high concentration of Cu, Zn, Pb, Ni and Fe, and low concentration of Si and Zr. Furthermore, three possible contamination sources of this type of sediment were revealed by Factor Analysis. The combination of sediment analysis and multivariate statistical techniques used provides new insights into the contamination depositional history of Nankan River and could be similarly applied to other river systems to determine the scale of anthropogenic contamination.

Flow, Sediment Supply, and Channel Width Controls on Gravel Bedform Dynamics

NASA Astrophysics Data System (ADS)

Nelson, P. A.; Morgan, J. A.

2017-12-01

Heterogeneous, coarse-grained riverbeds often self-organize into migrating bedforms such as gravel dunes or bedload sheets. It has recently been suggested that sediment supply and the relative mobility of the bed surface sediment affects the type of bedforms that may be present in gravel-bed rivers; however, our understanding of gravel bedform dynamics remains well behind that of bedforms in sandy channels. Here, we present results from flume experiments in which we investigate how the formation and dynamics of gravel bedforms is affected by changes in discharge, sediment supply, and channel geometry. Experiments were conducted in a 1.1-m wide, 18-m long, sediment-feed flume. The initial bed material and the sediment feed mixture was composed of a sediment mixture ranging in size from 0.5-4 mm, with a median value of 3.6 mm. We used two channel geometries (a straight channel and a channel with sinusoidal width variations) and conducted three experimental runs for each geometry: 1) equilibrium sediment supply and steady flow, 2) equilibrium sediment supply and repeated hydrographs, and 3) doubled sediment supply and repeated hydrographs. During the experiments, low-amplitude, migrating bedforms developed and their dynamics were tracked both visually and via collection of repeated structure-from-motion topographic datasets. In the constant-width geometry, bedform amplitudes and migration rates were relatively constant under steady flow, but when subjected to repeated hydrographs the average bedform celerity decreased by about 50% and the amplitude of the bedforms increased and decreased with the changing flow rate. At twice the equilibrium sediment supply, the bedforms organized into an alternating pattern. This pattern was most pronounced at the lower flow rates, and became less stable at the higher discharges of the repeat hydrographs. Preliminary results suggest bedform celerity in the variable width geometry under steady flow and equilibrium sediment supply was half the celerity of the bedforms for the same conditions in the straight-walled geometry. These experiments suggest that variations in discharge, sediment supply, and channel geometry play an important role in the formation and dynamics of bedforms in gravel-bed rivers.

The influence of a semi-arid sub-catchment on suspended sediments in the Mara River, Kenya

PubMed Central

2018-01-01

The Mara River Basin in East Africa is a trans-boundary basin of international significance experiencing excessive levels of sediment loads. Sediment levels in this river are extremely high (turbidities as high as 6,000 NTU) and appear to be increasing over time. Large wildlife populations, unregulated livestock grazing, and agricultural land conversion are all potential factors increasing sediment loads in the semi-arid portion of the basin. The basin is well-known for its annual wildebeest (Connochaetes taurinus) migration of approximately 1.3 million individuals, but it also has a growing population of hippopotami (Hippopotamus amphibius), which reside within the river and may contribute to the flux of suspended sediments. We used in situ pressure transducers and turbidity sensors to quantify the sediment flux at two sites for the Mara River and investigate the origin of riverine suspended sediment. We found that the combined Middle Mara—Talek catchment, a relatively flat but semi-arid region with large populations of wildlife and domestic cattle, is responsible for 2/3 of the sediment flux. The sediment yield from the combined Middle Mara–Talek catchment is approximately the same as the headwaters, despite receiving less rainfall. There was high monthly variability in suspended sediment fluxes. Although hippopotamus pools are not a major source of suspended sediments under baseflow, they do contribute to short-term variability in suspended sediments. This research identified sources of suspended sediments in the Mara River and important regions of the catchment to target for conservation, and suggests hippopotami may influence riverine sediment dynamics. PMID:29420624

Heavy metal contamination of sediments in the upper connecting channels of the Great Lakes

USGS Publications Warehouse

Nichols, S. Jerrine; Manny, Bruce A.; Schloesser, Donald W.; Edsall, Thomas A.

1991-01-01

In 1985, sampling at 250 stations throughout the St. Marys, St. Clair, and Detroit rivers and Lake St. Clair — the connecting channels of the upper Great Lakes — revealed widespread metal contamination of the sediments. Concentrations of cadmium, chromium, copper, lead, mercury, nickel, and zinc each exceeded U.S. Environmental Protection Agency sediment pollution guidelines at one or more stations throughout the study area. Sediments were polluted more frequently by copper, nickel, zinc, and lead than by cadmium, chromium, or mercury. Sediments with the highest concentrations of metals were found (in descending order) in the Detroit River, the St. Marys River, the St. Clair River, and Lake St. Clair. Although metal contamination of sediments was most common and sediment concentrations of metals were generally highest near industrial areas, substantial contamination of sediments by metals was present in sediment deposition areas up to 60 km from any known source of pollution.

Estimation of annual suspended-sediment fluxes, 1931-95, and evaluation of geomorphic changes, 1950-2010, in the Arkansas River near Tulsa, Oklahoma

USGS Publications Warehouse

Lewis, Jason M.; Smith, S. Jerrod; Buck, Stephanie D.; Strong, Scott A.

2011-01-01

An understanding of fluvial sediment transport and changing channel morphology can assist planners in making responsible decisions with future riverine development or restoration projects. Sediment rating curves can serve as simple models and can provide predictive tools to estimate annual sediment fluxes. Sediment flux models can aid in the design of river projects by providing insight to past and potential future sediment fluxes. Historical U.S. Geological Survey suspended-sediment and discharge data were evaluated to estimate annual suspended-sediment fluxes for two stations on the Arkansas River located downstream from Keystone Dam in Tulsa County. Annual suspended-sediment fluxes were estimated from 1931-95 for the Arkansas River at Tulsa streamflow-gaging station (07164500) and from 1973-82 for the Arkansas River near Haskell streamflow-gaging station (07165570). The annual flow-weighted suspended-sediment concentration decreased from 1,970 milligrams per liter to 350 milligrams per liter after the completion of Keystone Dam at the Tulsa station. The streambed elevation at the Arkansas River at Tulsa station has changed less than 1 foot from 1970 to 2005, but the thalweg has shifted from a location near the right bank to a position near the left bank. There was little change in the position of most of the banks of the Arkansas River channel from 1950 to 2009. The most substantial change evident from visual inspection of aerial photographs was an apparent decrease in sediment storage in the form of mid-channel and meander bars. The Arkansas River channel between Keystone Dam and the Tulsa-Wagoner County line showed a narrowing and lengthening (increase in sinuosity) over the transition period 1950-77 followed by a steady widening and shortening of the river channel (decrease in sinuosity) during the post-dam (Keystone) periods 1977-85, 1985-2003, and 2003-10.

What are the contemporary sources of sediment in the Mississippi River?

NASA Astrophysics Data System (ADS)

Hassan, M. A.; Roberge, L.; Church, M.; More, M.; Donner, S. D.; Leach, J.; Ali, K. F.

2017-09-01

Within the last two centuries, the Mississippi River basin has been transformed by changes in land use practices, dam construction, and training of the rivers for navigation. Here we analyze the contemporary patterns of fluvial sediment yield in the Mississippi River basin using all available data in order to assess the influence of regional land condition on the variation of sediment yield within the basin. We develop regional-scale relations between specific sediment yield (yield per unit area) and drainage area to reveal contemporary regional sediment yield patterns and source areas of riverine sediments. Extensive upland erosion before the development of soil conservation practices exported large amounts of sediment to the valleys and floodplains. We show that sediment today is sourced primarily along the river valleys from arable land, and from stream bank and channel erosion, with sediment yields from areas dominated by arable land 2 orders of magnitude greater than that of grassland dominated areas. Comparison with the "T factor," a commonly quoted measure of agricultural soil resilience suggests that the latter may not reflect contemporary soil loss from the landscape.

Tidal river sediments in the Washington, D.C. area. 111 Biological effects associated with sediment contamination

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

Schlekat, C.E.; McGee, B.L.; Boward, D.M.

1994-06-01

Sediment toxicity and benthic marcroinvertebrate community structure were measured as one component of a study conceived to determine the distribution and effect of sediment contamination in tidal freshwater portions of the Potomac and Anacostia rivers in the Washington, D.C., area. Samples were collected at 15 sites. Analyses included a partial life cycle (28 d) whole sediment test using the amphipod Hyalella azteca (Talitridae) and an assessment of benthic community structure. Survival and growth (as estimated by amphipod length) were experimental endpoints for the toxicity test. Significant mortality was observed in 5 to 10 sites in the lower Anacostia River basinmore » and at the main channel Potomac River site. Sublethal toxicity, as measured by inhibition of amphipod growth, was not observed. Toxicity test results were in general agreement with synoptically measured sediment contaminant concentrations. Porewater total ammonia (NH{sub 3} + NH{sub 4}{sup +}) appears to be responsible for the toxicity of sediments from the Potomac River, while correlation analysis and simultaneously extracted metals: acid volatile sulfide (SEM:AVA) results suggest that the toxicity associated with Anacostia River sediments was due to organic compounds. Twenty-eight macroinvertebrate taxa were identified among all sites, with richness varying from 5 to 17 taxa per site. Groups of benthic assemblages identified by group-average cluster analysis exhibited variable agreement with sediment chemical and sediment toxicity results. Integration of toxicological, chemical, and ecological components suggests that adverse environmental effects manifest in lower Anacostia River benthos result from chemical contamination of sediment. 37 refs., 2 figs., 7 tabs.« less

What Role do Hurricanes Play in Sediment Delivery to Subsiding River Deltas?

NASA Astrophysics Data System (ADS)

Smith, J. E., IV

2016-02-01

James E. Smith IV1, Samuel J. Bentley, Sr.1, Gregg A. Snedden2, Crawford White1 Department of Geology and Geophysics and Coastal Studies Institute, Louisiana State University, Baton Rouge, LA 70803 USA United States Geological Survey, National Wetlands Research Center, Baton Rouge LA 70803 USA The Mississippi River Delta has undergone tremendous land loss over the past century due to natural and anthropogenic influences, a fate shared by many river deltas globally. A globally unprecedented effort to restore and sustain the remaining subaerial portions of the delta is now underway, an endeavor that is expected to cost $50-100B over the next 50 yr. Success of this effort requires a thorough understanding of natural and anthropogenic controls on sediment supply, accumulation, and delta geomorphology. In the Mississippi River Delta, hurricanes have been paradoxically identified as both agents of widespread land loss, and positive influences for marsh vertical sediment accretion. We present the first multi-decadal chronostratigraphic assessment of sediment supply for a major coastal basin of the Mississippi River Delta that assesses both fluvial and hurricane-induced contributions to sediment accumulation in deltaic wetlands. Twenty seven cores have been analyzed for radioisotope geochronology and organic content to establish the chronology of mineral sediment supply to the wetlands over the past 70 years. Our findings indicate that over multidecadal timescales, hurricane-induced sediment delivery may be an important contributor for deltaic wetland vertical accretion, but the contribution from hurricanes to long-term sediment accumulation is substantially less than sediment delivery supplied by existing and planned river-sediment diversions at present-day river-sediment loads.

Acid mine drainage pollution in the Tinto and Odiel rivers (Iberian Pyrite Belt, SW Spain) and bioavailability of the transported metals to the Huelva Estuary.

PubMed

Nieto, José Miguel; Sarmiento, Aguasanta M; Olías, Manuel; Canovas, Carlos R; Riba, Inmaculada; Kalman, Judit; Delvalls, T Angel

2007-05-01

The Tinto and Odiel rivers are seriously affected by acid mine drainage (AMD) from the long-term mining activities in Iberian Pyrite Belt (IPB). As a consequence, the Huelva estuary is heavily contaminated by metals and metalloids. This study presents an estimation of the seasonal variation, and the dissolved contaminant load transported by both rivers from February 2002 to September 2004. Besides, toxicity and bioaccumulation tests with the sediments of the estuary have been conducted in order to measure the mobility of the toxic metals. Results show that the Tinto and Odiel rivers transport enormous quantities of dissolved metals to the estuary: 7900 t yr(-1) of Iron (Fe), 5800 t yr(-1) Aluminium (Al), 3500 t yr(-1) Zinc (Zn), 1700 t yr(-1) Copper (Cu), 1600 t yr(-1) Manganese (Mn) and minor quantities of other metals and metalloids. These values represent 37% of the global gross flux of dissolved Zn transported by rivers in to the ocean, and 15% of the global gross flux of dissolved Cu. These metals and metalloids usually sink in the estuarine sediments due to pH and salinity changes. The increase of salinity in the estuary favours the adsorption and trapping of metals. For this reason, the mobility and bioavailability of metals such as Zn, Cd and Cu is higher in sediments located in the area of fresh water influence that in sediments located in the marine influenced area of the estuary, showing a higher percentage of fractionation and bioaccumulation of these metals in the station influenced by the fresh water environment.

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

USGS Publications Warehouse

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

2016-05-17

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

Influence of Cattle Trails on Runoff Quantity and Quality.

PubMed

Miller, Jim J; Curtis, Tony; Chanasyk, David S; Willms, Walter D

2017-03-01

Cattle trails in grazed pastures close to rivers may adversely affect surface water quality of the adjacent river by directing runoff to it. The objective of this 3-yr study (2013-2015) in southern Alberta, Canada, was to determine if cattle trails significantly increased the risk of runoff and contaminants (sediment, nutrients) compared with the adjacent grazed pasture (control). A portable rainfall simulator was used to generate artificial rainfall (140 mm h) and runoff. The runoff properties measured were time to runoff and initial abstraction (infiltration), total runoff depth and average runoff rates, as well as concentrations and mass loads of sediment, N, and P fractions. Cattle trails significantly ( ≤ 0.10) decreased time to runoff and initial abstraction (26-32%) in the 2 yr measured and increased total runoff depth, runoff coefficients, and average runoff rates (21-51%) in 2 of 3 yr. Concentrations of sediment, N, and P fractions in runoff were not significantly greater for cattle trails than for control areas. However, mass loads of total suspended solids (57-85% increase), NH-N (31-90%), and dissolved reactive P (DRP) (30-92%) were significantly greater because of increased runoff volumes. Overall, runoff quantity and loads of sediment, NH-N, and DRP were greater for cattle trails compared with the adjacent grazed pasture, and hydrologic connection with cattle-access sites on the riverbank suggests that this could adversely affect water quality in the adjacent river. Extrapolation of the study results should be tempered by the specific conditions represented by this rainfall simulation study. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

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

NASA Astrophysics Data System (ADS)

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

2016-04-01

More than half of the Swiss electricity is produced by hydropower. Large price fluctuations cause severe hydropeaking flow regimes due to corresponding production fluctuations, which undisputedly have a negative impact on aquatic biota. Water diversion due to dams on the other hand imposes downstream residual flow regimes. The absence of flood events and regular sediment supply disrupts sediment dynamics and disconnects floodplains, which are habitats of high value, from its main channel. The residual-flow controlled reach at the Sarine river in western Switzerland is the subject of the present study. The Sarine meanders strongly and the river reach under analysis has a bed incision of locally more than 100 m. Its incision provokes the isolation of the river which is consequently minimally touched by human structures and shows a natural geomorphology. Since the construction of a dam upstream this reach in 1948, aiming at the water abstraction to hydropower, vegetation could establish and the active floodplain decreased its area, as airborne images show. Nevertheless, it is classified as a floodplain of national importance and it has been under protection since 1992. It is supposed to be a valuable habitat for a wide range of organisms. The Hydromorphological Index of Diversity (HMID) is a simple tool for quantifying the habitat richness in a river reach, taking into account the mean values and the variation of water depth and flow velocity. For channelized rivers, HMID values from up to 5 are expected, while morphological pristine sites with a high spatial variability of water depth and velocity show values of 9 or higher. For the residual flow of the Sarine River, flow depth and velocity were measured using ADCP and ADV. The results are compared with a nearby natural reference river and the outcome of a 2D numerical simulation. Finally, the behaviour and limitations of the HMID, in a hydropower affected river, are discussed. In the close future an artificial flood is expected in the Sarine in order to reactivate the sediment dynamics. Using 2D numerical simulations in combination with a well understanding of the HMID an optimal planning of this event will be implemented. The present study is financed by the Swiss National Foundation (SNF), National Research Project 70, Energy Turnaround.

Sediment Quality and Comparison to Historical Water Quality, Little Arkansas River Basin, South-Central Kansas, 2007

USGS Publications Warehouse

Juracek, Kyle E.; Rasmussen, Patrick P.

2008-01-01

The spatial and temporal variability in streambed-sediment quality and its relation to historical water quality was assessed to provide guidance for the development of total maximum daily loads and the implementation of best-management practices in the Little Arkansas River Basin, south-central Kansas. Streambed-sediment samples were collected at 26 sites in 2007, sieved to isolate the less than 63-micron fraction (that is, the silt and clay), and analyzed for selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 25 trace elements, and the radionuclides beryllium-7, cesium-137, lead-210, and radium-226. At eight sites, streambed-sediment samples also were collected and analyzed for bacteria. Particulate nitrogen, phosphorus, and organic carbon concentrations in the streambed sediment varied substantially spatially and temporally, and positive correlations among the three constituents were statistically significant. Along the main-stem Little Arkansas River, streambed-sediment concentrations of particulate nitrogen and phosphorus generally were larger at and downstream from Alta Mills, Kansas. The largest particulate nitrogen concentrations were measured in samples collected in the Emma Creek subbasin and may be related to livestock and poultry production. The largest particulate phosphorus concentrations in the basin were measured in samples collected along the main-stem Little Arkansas River downstream from Alta Mills, Kansas. Particulate nitrogen, phosphorus, and organic carbon content in the water and streambed-sediment samples typically decreased as streamflow increased. This inverse relation may be caused by an increased contribution of sediment from channel-bank sources during high flows and (or) increased particle sizes transported by the high flows. Trace element concentrations in the streambed sediment varied from site to site and typically were less than threshold-effects guidelines for possible adverse biological effects. The largest copper, lead, silver, and zinc concentrations, measured for a sample collected from Sand Creek downstream from Newton, Kansas, likely were related to urban sources of contamination. Radionuclide activities and bacterial densities in the streambed sediment varied throughout the basin. Variability in the former may be indicative of subbasin differences in the contribution of sediment from surface-soil and channel-bank sources. Streambed sediment may be useful for reconnaissance purposes to determine sources of particulate nitrogen, phosphorus, organic carbon, and other sediment-associated constituents in the basin. If flow conditions prior to streambed-sediment sampling and during water-quality sampling are considered, it may be possible to use streambed sediment as an indicator of water quality for nitrogen, phosphorus, and organic carbon. Flow conditions affect sediment-associated constituent concentrations in streambed-sediment and water samples, in part, because the sources of sediment (surface soils, channel banks) can vary with flow as can the size of the particles transported.

Suspended-sediment data in the Salt River basin, Missouri

USGS Publications Warehouse

Berkas, Wayne R.

1983-01-01

Suspended-sediment data collected at six stations in the Salt River basin during 1980-82 are presented. The estimated average annual suspended-sediment load is 1,390,000 tons per year from a geomorphic examination, and 1,330,000 tons per year from periodic sampling at Salt River near Monroe City, Mo. The suspended-sediment load from the major tributaries of the Salt River during 1981 was 1,610,000 tons, which is larger than the estimated values due to above-normal rainfall and runoff. (USGS)

Biomarkers of effects of hypoxia and oil-shale contaminated sediments in laboratory-exposed gibel carp (Carassius auratus gibelio).

PubMed

Kreitsberg, Randel; Baršienė, Janina; Freiberg, Rene; Andreikėnaitė, Laura; Tammaru, Toomas; Rumvolt, Kateriina; Tuvikene, Arvo

2013-12-01

In North-East Estonia, considerable amounts of toxicants (e.g. polycyclic aromatic hydrocarbons (PAHs), phenols, heavy metals) leach into water bodies through discharges from the oil-shale industry. In addition, natural and anthropogenic hypoxic events in water bodies affect the health of aquatic organisms. Here we report a study on the combined effects of contaminated sediment and hypoxia on the physiology of gibel carp (Carssius auratus gibelio). We conducted a laboratory exposure study that involved exposure to polluted sediments from oil-shale industries (River Purtse) and sediments from a relatively clean environment (River Selja), together with sediments spiked with PAHs. The oxygen content (saturation vs. hypoxia (< 2 mg/L)) was changed to reflect hypoxia. A multi-biomarker approach was chosen to enable the combined effects to be assessed comprehensively and integratively. We used HPLC to measure the PAH concentration in sediment and fish muscle, fixed wavelength fluorescence (FF) analyses to indicate the presence of PAH metabolites in fish bile, and nuclear abnormalities in erythrocytes as markers of geno- and cyto-toxicity; and we monitored the change in body condition and measured EROD activity to indicate CYP1A induction. High levels of PAH conjugates in fish bile were found in the group exposed to the Purtse River sediment under hypoxia. The results suggested that induction of the CYP1A gene was modulated by hypoxia as well as by heavy metals. We found a correlation between several erythrocyte abnormalities (8-shaped nuclei and blebbed nuclei) and PAH metabolite content in fish. In conclusion, a measurable effect of pollution from the oil-shale industry on fish health parameters was clear under different oxygen levels. © 2013 Elsevier Inc. All rights reserved.

Modeling Anthropogenic Impact on Sediment Balance and Relative Sea-Level Rise in Contemporary and Future Deltas

NASA Astrophysics Data System (ADS)

Tessler, Z. D.; Vorosmarty, C. J.; Overeem, I.; Syvitski, J. P.

2017-12-01

Modern deltas are dependent on human-mediated freshwater and sediment fluxes. Changes to these fluxes impact delta biogeophysical functioning, and affect the long-term sustainability of these landscapes for both human and natural systems. Here we present contemporary estimates of long-term mean sediment balance and relative sea-level rise across 46 global deltas. We model ongoing development and scenarios of future water resource management and hydropower infrastructure in upstream river basins to explore how changing sediment fluxes impact relative sea-level in coastal delta systems. Model results show that contemporary sediment fluxes, anthropogenic drivers of land subsidence, and sea-level rise result in relative sea-level rise rates in deltas that average 6.8 mm/year. Currently planned or under-construction dams can be expected to increase rates of relative sea-level rise on the order of 1 mm/year. Some deltas systems, including the Magdalena, Orinoco, and Indus, are highly sensitive to future impoundment of river basins, with RSLR rates increasing up to 4 mm/year in a high-hydropower-utilization scenario. Sediment fluxes may be reduced by up to 60% in the Danube and 21% in the Ganges-Brahmaputra-Megnha if all currently planned dams are constructed. Reduced sediment retention on deltas due to increased river channelization and local flood controls increases RSLR on average by nearly 2 mm/year. Long-term delta sustainability requires a more complete understanding of how geophysical and anthropogenic change impact delta geomorphology. Strategies for sustainable delta management that focus on local and regional drivers of change, especially groundwater and hydrocarbon extraction and upstream dam construction, can be highly impactful even in the context of global climate-induced sea-level rise.

Morphodynamics and Sediment Transport on the Huanghe (Yellow River) Delta: Work in Progress

NASA Astrophysics Data System (ADS)

Kineke, G. C.; Calson, B.; Chadwick, A. J.; Chen, L.; Hobbs, B. F.; Kumpf, L. L.; Lamb, M. P.; Ma, H.; Moodie, A. J.; Mullane, M.; Naito, K.; Nittrouer, J. A.; Parker, G.

2017-12-01

Deltas are perhaps the most dynamic of coastal landforms with competing processes that deliver and disperse sediment. As part of the NSF Coastal SEES program, an interdisciplinary team of scientists from the US and China are investigating processes that link river and coastal sediment transport responsible for morphodynamic change of the Huanghe delta- an excellent study site due to its high sediment load and long history of natural and engineered avulsions, that is, abrupt shifts in the river course. A fundamental component of the study is a better understanding of sediment transport physics in a river system that transports mostly silt. Through theory and data analysis, we find that fine-grained rivers fail to develop full scale dunes, which results in faster water flow and substantially larger sediment fluxes as compared to sandy rivers (e.g. the Mississippi River). We also have developed new models for sediment-size dependent entrainment that are needed to make longer term predictions of river sedimentation patterns. On the delta front, we are monitoring the high sediment flux to the coast, which results in steep foresets and ideal conditions for off-shore sediment delivery via gravity flows. These constraints on sediment transport are being used to develop new theory for where and when rivers avulse - including the effects of variable flood discharge, sediment supply, and sea level rise -and how deltas ultimately grow through repeated cycles of lobe development. Flume experiments and field observations are being used to test these models, both in the main channel of the Huanghe and in channels abandoned after historic avulsions. Abandoned channels and floodplains are now dominated by coastal sediment transport through a combination of wave resuspension and tidal transport, settling lag and reverse estuarine circulation. Finally, the field and laboratory tested numerical models are being used as inputs to define a cost curve for efficient avulsion management of the Huanghe delta by minimizing expected flood-damage cost. Taken together, these studies can inform management policies and promote consideration of the natural evolution of deltas to achieve sustainability.

Suspended Sediment Loads and Tributary Inputs in the Mississippi River below St. Louis, MO, 1990-2013 Compared With Earlier Results

NASA Astrophysics Data System (ADS)

Allison, M. A.; Biedenharn, D. S.; Dahl, T. A.; Kleiss, B.; Little, C. D.

2017-12-01

Annual suspended sediment loads and water discharges were calculated in the Mississippi River mainstem channel, and at the most downstream gaging station for major tributaries, from below the Missouri confluence near St. Louis, MO to Belle Chasse, LA, as well as down the Atchafalaya distributary for water years 1990 to 2013. The purpose of the present study was to assess changes in the Mississippi River sediment budget over the past half century, and to examine the continuing role that anthropogenic (e.g., dams, river control works, soil conservation practices) and natural (e.g., rainfall and denudation rates) factors have in controlling these changes. Sixteen of the 17 measured Mississippi River tributaries decreased in total suspended sediment load) from 1970-1978 to 1990-2013. The largest decreases occurred in the 2nd (Ohio River, 41% of 1970-1978) and 4th (Arkansas River, 45% of 1970-1978) largest water sources to the Mississippi. The Missouri River remains the largest Mississippi River tributary in terms of average annual suspended sediment flux; its relative contribution increased from 38% to 51% of the total flux from the 17 measured tributaries, even as its total suspended flux declined by 13%. Averaged over the period of study (WY 1990-2013), water flux increased by 468% and sediment flux increased by 37,418% downstream from the Gavin's Point Dam to the confluence with the Mississippi. Possible reasons for this disproportional increase in suspended sediment load downstream include sediment-rich contributions from 2nd order rivers below the dams and channel incision. Suggested station improvements to the system include improved monitoring of the Upper Mississippi and Arkansas River tributaries, establishing additional mainstem stations in the reach between Thebes, IL and Arkansas City, AR, and standardization of laboratory and field methodologies to eliminate a major source of station-to-station and time-series variability in the sediment budgeting.

Distribution and abundance of archaeal and bacterial ammonia oxidizers in the sediments of the Dongjiang River, a drinking water supply for Hong Kong.

PubMed

Sun, Wei; Xia, Chunyu; Xu, Meiying; Guo, Jun; Wang, Aijie; Sun, Guoping

2013-01-01

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) play important roles in nitrification. However, limited information about the characteristics of AOA and AOB in the river ecosystem is available. The distribution and abundance of AOA and AOB in the sediments of the Dongjiang River, a drinking water source for Hong Kong, were investigated by clone library analysis and quantitative real-time PCR. Phylogenetic analysis showed that Group 1.1b- and Group 1.1b-associated sequences of AOA predominated in sediments with comparatively high carbon and nitrogen contents (e.g. total carbon (TC) >13 g kg(-1) sediment, NH4(+)-N >144 mg kg(-1) sediment), while Group 1.1a- and Group 1.1a-associated sequences were dominant in sediments with opposite conditions (e.g. TC <4 g kg(-1) sediment, NH4(+)-N <93 mg kg(-1) sediment). Although Nitrosomonas- and Nitrosospira-related sequences of AOB were detected in the sediments, nearly 70% of the sequences fell into the Nitrosomonas-like B cluster, suggesting similar sediment AOB communities along the river. Higher abundance of AOB than AOA was observed in almost all of the sediments in the Dongjiang River, while significant correlations were only detected between the distribution of AOA and the sediment pH and TC, which suggested that AOA responded more sensitively than AOB to variations of environmental factors. These results extend our knowledge about the environmental responses of ammonia oxidizers in the river ecosystem.

Sediment connectivity at source-bordering aeolian dunefields along the Colorado River in the Grand Canyon, USA

NASA Astrophysics Data System (ADS)

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

2017-04-01

Aeolian dunefields that are primarily built and maintained with river-derived sediment are found in many river valleys throughout the world and are impacted by changes in climate, land use, and river regulation. Quantifying the dynamic response of these aeolian dunefields to alterations in river flow is especially difficult given the highly correlated nature of the interacting geomorphic and sediment transport processes that drive their formation and maintenance. We characterize the effects of controlled river floods on changes in sediment connectivity at source-bordering aeolian dunefields in the Grand Canyon, USA. Controlled floods from the Glen Canyon Dam are used to build sandbars along the Colorado River in Grand Canyon which provide the main sediment source for aeolian dunefields. Aeolian dunefields are a primary resource of concern for land managers in the Grand Canyon because they often contain buried archaeological features. To characterize dunefield response to controlled floods, we use a novel, automated approach for the mechanistic segregation of geomorphic change to discern the geomorphic processes responsible for driving topographic change in very high resolution digital elevation models-of-difference (DODs) that span multiple, consecutive controlled river floods at source-bordering dunefields. We subsequently compare the results of mechanistic segregation with modelled estimates of aeolian dunefield evolution in order to understand how dunefields respond to contemporary, anthropogenically-driven variability in sediment supply and connectivity. These methods provide a rapid technique for sediment budgeting and enable the inference of spatial and temporal patterns in sediment flux between the fluvial and aeolian domains. We anticipate that this approach will be adaptable to other river valleys where the interactions of aeolian, fluvial, and hillslope processes drive sediment connectivity for the maintenance of source-bordering aeolian dunefields.

Geophysical bed sediment characterization of the Androscoggin River from the former Chlor-Alkali Facility Superfund Site, Berlin, New Hampshire, to the state border with Maine, August 2009

USGS Publications Warehouse

Degnan, James R.; Teeple, Andrew; Johnston, Craig M.; Marvin-DiPasquale, Mark C.; Luce, Darryl

2011-01-01

The former Chlor-Alkali Facility in Berlin, New Hampshire, was listed on the U.S. Environmental Protection Agency National Priorities List in 2005 as a Superfund site. The Chlor-Alkali Facility lies on the east bank of the Androscoggin River. Elemental mercury currently discharges from that bank into the Androscoggin River. The nature, extent, and the speciation of mercury and the production of methyl mercury contamination in the adjacent Androscoggin River is the subject of continuing investigations. The U.S. Geological Survey, in cooperation with Region I of the U.S. Environmental Protection Agency, used geophysical methods to determine the distribution, thickness, and physical properties of sediments in the Androscoggin River channel at a small area of an upstream reference reach and downstream from the site to the New Hampshire–Maine State border. Separate reaches of the Androscoggin River in the study area were surveyed with surface geophysical methods including ground-penetrating radar and step-frequency electromagnetics. Results were processed to assess sediment characteristics including grain size, electrical conductivity, and pore-water specific conductance. Specific conductance measured during surface- and pore-water sampling was used to help interpret the results of the geophysical surveys. The electrical resistivity of sediment samples was measured in the laboratory with intact pore water for comparison with survey results. In some instances, anthropogenic features and land uses, such as roads and power lines affected the detection of riverbed properties using geophysical methods; when this occurred, the data were removed. Through combining results, detailed riverbed sediment characterizations were made. Results from ground-penetrating radar surveys were used to image and measure the depth to the riverbed, depth to buried riverbeds, riverbed thickness and to interpret material-type variations in terms of relative grain size. Fifty two percent of the riverbed in the study area was covered with gravel and finer sediments. The electrically resistive river water and sediment in this study area were conducive to the penetration of the ground-penetrating radar and step-frequency electromagnetic signals and allowed for effective sediment characterization by geophysical methods. The reach between the former Chlor-Alkali Facility and the Riverside Dam, had small areas of fine sediment (estimated 11 percent of riverbed area), found on the upstream left bank and the downstream right bank, with an electromagnetic conductivity (31.4 millisiemens per meter (mS/m) maximum) that was higher than the upstream reference reach. The greatest electromagnetic conductivity (195 mS/m), pore-water specific conductance (324 mS/m) and lab measured sediment conductivity of (76.8 mS/m, measured with a direct-current resistivity test box) in the study were measured approximately 1 mile (mi) downstream of the site from a sandbar on the left bank. Reaches adjacent to and within 2 mi downstream from the site had elevated electromagnetic conductivity despite having lower estimated percentages of riverbed area covered in sediment (11, 25, and 61 percent, respectively) than the reference reach (97). Typically finer grained sediment with similar mineralogy will be more conductive. The Shelburne Reservoir is approximately 8 mi downstream from the site had the second greatest pore-water specific conductance measured, 45.8 mS/m. Many of the locations with the largest step-frequency electromagnetic values have not been sampled for pore water and sediment.

Hyperpycnal sediment discharge from semiarid southern California rivers: Implications for coastal sediment budgets

USGS Publications Warehouse

Warrick, J.A.; Milliman, John D.

2003-01-01

Southern California rivers discharge hyperpycnal (river density greater than ocean density) concentrations of suspended sediment (>40 g/L, according to buoyancy theory) during flood events, mostly during El Nin??o-Southern Oscillation (ENSO) conditions. Because hyperpycnal river discharge commonly occurs during brief periods (hours to occasionally days), mean daily flow statistics often do not reveal the magnitude of these events. Hyperpycnal events are particularly important in rivers draining the Transverse Range and account for 75% of the cumulative sediment load discharged by the Santa Clara River over the past 50 yr. These events are highly pulsed, totaling only ??? 30 days (??? 0.15% of the total 50 yr period). Observations of the fate of sediment discharge, although rare, are consistent with hyperpycnal river dynamics and the high likelihood of turbidity currents during these events. We suggest that much of the sediment load initially bypasses the littoral circulation cells and is directly deposited on the adjacent continental shelf, thus potentially representing a loss of immediate beach sand supply. During particularly exceptional events (>100 yr recurrence intervals), flood underflows may extend past the shelf and escape to offshore basins.

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

PubMed

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

2016-03-01

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

Human alterations, dynamic equilibrium, and riparian ecosystem responses along selected rivers in Tuscany, Italy (Invited)

NASA Astrophysics Data System (ADS)

Hupp, C. R.; Rinaldi, M.

2010-12-01

Many, if not most, streams have been mildly to severely affected by human disturbance, which complicates efforts to understand riparian ecosystems. Mediterranean regions have a long history of human influences including: dams, stream channelization, mining of sediment, and levee /canal construction. Typically these alterations reduce the ecosystem services that functioning floodplains provide and may negatively impact the natural ecology of floodplains through reductions in suitable habitats, biodiversity, and nutrient cycling. Additionally, human alterations typically shift affected streams away from a state of natural dynamic equilibrium, where net sediment deposition is approximately in balance with net erosion. Lack of equilibrium typically affects the degree to which floodplain ecosystems are connected to streamflow regime. Low connectivity, usually from human- or climate-induced incision, may result in reduced flow on floodplains and lowered water tables. High connectivity may result in severe sediment deposition. Connectivity has a direct impact on vegetation communities. Riparian vegetation distribution patterns and diversity relative to various fluvial geomorphic channel patterns, landforms, and processes are described and interpreted for selected rivers of Tuscany, Central Italy; with emphasis on channel evolution following human impacts. Multivariate analysis reveals distinct quantitative vegetation patterns related to six fluvial geomorphic surfaces. Analysis of vegetation data also shows distinct associations of plants with adjustment processes related to the stage of channel evolution. Plant distribution patterns coincide with disturbance/landform/soil moisture gradients. Species richness increases from channel bed to terrace and on heterogeneous riparian areas, while species richness decreases from moderate to intense incision and from low to intense narrowing. As a feedback mechanism, woody vegetation in particular may facilitate geomorphic recovery of floodplains by affecting sedimentation dynamics. Identification and understanding of critical fluvial parameters related to floodplain connectivity (e.g. stream gradient, grain-size, and hydrography) and spatial and temporal sediment deposition/erosion process trajectories should facilitate management efforts to retain and/or regain important ecosystem services.

Occurrence of Selected Nutrients, Trace Elements, and Organic Compounds in Streambed Sediment in the Lower Chena River Watershed near Fairbanks, Alaska, 2002-03

USGS Publications Warehouse

Kennedy, Ben W.; Hall, Cassidee C.

2009-01-01

In 2002-03, the U.S. Geological Survey collected samples of streambed sediment at 18 sites in the lower Chena River watershed for analysis of selected nutrients, traces elements, and organic compounds. The purpose of the project was to provide Federal, State, and local agencies as well as neighborhood committees, with information for consideration in plans to improve environmental conditions in the watershed. The exploratory sampling program included analysis of streambed sediment from the Chena River and Chena Slough, a tributary to the Chena River. Results were compared to streambed-sediment guidelines for the protection of aquatic life and to 2001-02 sediment data from Noyes Slough, a side channel of the lower Chena River. The median total phosphorus concentration in Chena Slough sediment samples, 680 milligrams per kilogram (mg/kg), was two orders of magnitude greater than median total phosphorus concentration in Chena River sediment samples of 5.2 mg/kg. Median concentrations of chloride and sulfate also were greater in Chena Slough samples. Low concentrations of nitrate were detected in most of the Chena Slough samples; nitrate concentrations were below method reporting limits or not detected in Chena River sediment samples. Streambed-sediment samples were analyzed for 24 trace elements. Arsenic, nickel, and zinc were the only trace elements detected in concentrations that exceeded probable-effect levels for the protection of aquatic life. Concentrations of arsenic in Chena Slough samples ranged from 11 to 70 mg/kg and concentrations in most of the samples exceeded the probable-effect guideline for arsenic of 17 mg/kg. Arsenic concentrations in samples from the Chena River ranged from 9 to 12 mg/kg. The background level for arsenic in the lower Chena River watershed is naturally elevated because of significant concentrations of arsenic in local bedrock and ground water. Sources of elevated concentrations of zinc in one sample, and of nickel in two samples, are unknown. With the exception of elevated arsenic levels in samples from Chena Slough, the occurrence and concentration of trace elements in the streambed sediments of Chena Slough and Chena River were similar to those in Noyes Slough sediment. Sediment samples were analyzed for 78 semivolatile organic compounds and 32 organochlorine pesticides and polychlorinated biphenyls (PCBs). Low concentrations of dimethylnaphthalene and p-Cresol were detected in most Chena Slough and Chena River sediment samples. The number of semivolatile organic compounds detected ranged from 5 to 21 in most Chena Slough sediment samples. In contrast, three or fewer semivolatile organic compounds were detected in Chena River sediment samples, most likely because chemical-matrix interference resulted in elevated reporting limits for organochlorine compounds in the Chena River samples. Low concentrations of fluoranthene, pyrene, and phenanthrene were detected in Chena Slough sediment. Relatively low concentrations of DDT or its degradation products, DDD and DDE, were detected in all Chena Slough samples. Concentrations of total DDT (DDT+DDD+DDE) in two Chena Slough sediment samples exceeded the effectsrange median aquatic-life criteria of 46.1 micrograms per kilogram (ug/kg). DDT concentrations in Chena River streambed-sediment samples were less than 20 ug/kg. Low concentrations of PCB were detected in two Chena Slough streambed-sediment samples. None of the concentrations of the polychlorinated biphenyls or semivolatile organic compounds for which the samples were analyzed exceeded available guidelines for the protection of aquatic life. With the exception of elevated total DDT in two Chena Slough samples, the occurrence and concentration of organochlorine compounds in Chena Slough and Chena River sediment were similar to those in samples collected from Noyes Slough in 2001-02.

Nesting ecology of Podocnemis expansa (Schweigger, 1812) and Podocnemis unifilis (Troschel, 1848) (Testudines, Podocnemididae) in the Javaés River, Brazil.

PubMed

Ferreira Júnior, P D; Castro, P T A

2010-02-01

Nest site has influence on incubation duration and hatching success of two Neotropical turtles, the giant Amazon River turtle (Podocnemis expansa) and yellow-spotted side-neck turtle (Podocnemis unifilis--'Tracajá'). The 2000 and 2001 nesting seasons have been monitored at the Javaés River in Bananal Island, Brazil. Although they nest on the same beaches, there is a separation of the nesting areas of P unifilis and P. expansa nests on the upper parts of the beach. The incubation duration for P. expansa is influenced by the nesting period, the height of the nest from the river, the clutch size, and the grain size in the site of the nest. Nests of Podocnemis expansa placed in coarse sediments have shorter incubation duration than those placed in finer sediments. The hatching success in P. expansa is influenced by grain size, incubation duration, and nesting period. The grain size is negatively correlated with hatching success, indicating that the nests situated in finer-grained sand have better chances of successful egg hatching than those in coarser-grained sand. Nests of the end of the reproductive season have lower hatching success and incubation duration than those at the start of the season. For P. unifilis, the nesting period and nest depth influence the incubation duration; moreover, the river dynamics significantly affect the hatching success. The oscillation of the river level and the moment of initial increase, the height of the nest from the river level, and the nesting period are all decisive components for hatching success. The results of this research show the importance of protecting areas with great geological diversity, wherein the features of the environment can affect the microenvironment of nests, with consequences on incubation duration and hatching success.

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

USGS Publications Warehouse

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

2014-01-01

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

Organic Carbon Trends, Loads, and Yields to the Sacramento-San Joaquin Delta, California, Water Years 1980 to 2000

USGS Publications Warehouse

Saleh, Dina K.; Domagalski, Joseph L.; Kratzer, Charles R.; Knifong, Donna L.

2003-01-01

Organic carbon, nutrient, and suspended sediment concentration data were analyzed for the Sacramento and San Joaquin River Basins for the period 1980-2000. The data were retrieved from three sources: the U.S. Geological Survey's National Water Information System, the U.S. Environmental Protection Agency's Storage and Retrieval System, and the California Interagency Ecological Program's relational database. Twenty sites were selected, all of which had complete records of daily streamflow data. These data met the minimal requirements of the statistical programs used to estimate trends, loads, and yields. The seasonal Kendall program was used to estimate trends in organic carbon, nutrient, and suspended sediment. At all 20 sites, analyses showed that in the 145 analyses for the seven constituents, 95 percent of the analyses had no significant trend. Dissolved organic carbon (DOC) concentrations were significant only for four sites: the American River at Sacramento, the Sacramento River sites near Freeport, Orestimba Creek at River Roads near Crows Landing, and the San Joaquin River near Vernalis. Loads were calculated using two programs, ESTIMATOR and LOADEST2. The 1998 water year was selected to describe loads in the Sacramento River Basin. Organic carbon, nutrient, and suspended sediment loads at the Sacramento River sites near Freeport included transported loads from two main upstream sites: the Sacramento River at Verona and the American River at Sacramento. Loads in the Sacramento River Basin were affected by the amount of water diverted to the Yolo Bypass (the amount varies annually, depending on the precipitation and streamflow). Loads at the Sacramento River sites near Freeport were analyzed for two hydrologic seasons: the irrigation season (April to September) and the nonirrigation season (October to March). DOC loads are lower during the irrigation season then they are during the nonirrigation season. During the irrigation season, water with low concentrations of DOC is released from reservoirs and used for irrigation. On the other hand, during the nonirrigation season, streamflow results from surface water runoff and has higher concentrations of organic carbon, nutrients, and suspended sediment. The 1986 and 1987 water years were selected to describe loads in the San Joaquin River Basin. Organic carbon, nutrient, and suspended sediment loads in the San Joaquin River near Vernalis included transported loads from upstream sites, such as the Mud and Salt Sloughs, the Merced River at River Roads Bridge near Newman, the Tuolumne River at Modesto, and the Stanislaus River at Ripon. Loads at the San Joaquin River near Vernalis also were analyzed for the two seasons. The DOC load for the San Joaquin River at Vernalis is slightly higher during the irrigation season. Yields were calculated in an attempt to rank the subbasins in the Sacramento and San Joaquin River Basins. Five sites delivered streamflow from agricultural and urban sources that had relatively high yields of organic carbon: Sacramento Slough near Knights Landing, Arcade Creek near Del Paso Heights, Salt Slough, Mud Slough, and Colusa Basin Drain at Road 99E near Knights Landing.

Middle Pleistocene infill of Hinkley Valley by Mojave River sediment and associated lake sediment: Depositional architecture and deformation by strike-slip faults

USGS Publications Warehouse

Miller, David; Haddon, Elizabeth; Langenheim, Victoria; Cyr, Andrew J.; Wan, Elmira; Walkup, Laura; Starratt, Scott W.

2018-01-01

Hinkley Valley in the Mojave Desert, near Barstow about 140 km northeast of Los Angeles and midway between Victorville Valley and the Lake Manix basin, contains a thick sedimentary sequence delivered by the Mojave River. Our study of sediment cores drilled in the valley indicates that Hinkley Valley was probably a closed playa basin with stream inflow from four directions prior to Mojave River inflow. The Mojave River deposited thick and laterally extensive clastic wedges originating from the southern valley that rapidly filled much of Hinkley Valley. Sedimentary facies representing braided stream, wetland, delta, and lacustrine depositional environments all are found in the basin fill; in some places, the sequence is greater than 74 m (245 ft) thick. The sediment is dated in part by the presence of the ~631 ka Lava Creek B ash bed low in the section, and thus represents sediment deposition after Victorville basin was overtopped by sediment and before the Manix basin began to be filled. Evidently, upstream Victorville basin filled with sediment by about 650 ka, causing the ancestral Mojave River to spill to the Harper and Hinkley basins, and later to Manix basin.Initial river sediment overran wetland deposits in many places in southern Hinkley Valley, indicating a rapidly encroaching river system. These sediments were succeeded by a widespread lake (“blue” clay) that includes the Lava Creek B ash bed. Above the lake sediment lies a thick section of interlayered stream sediment, delta and nearshore lake sediment, mudflat and/or playa sediment, and minor lake sediment. This stratigraphic architecture is found throughout the valley, and positions of lake sediment layers indicate a successive northward progression in the closed basin. A thin overlapping sequence at the north end of the valley contains evidence for a younger late Pleistocene lake episode. This late lake episode, and bracketing braided stream deposits of the Mojave River, indicate that the river avulsed through the valley, rather than continuing toward Lake Manix, during the late Pleistocene. Two dextral strike-slip fault zones, the Lockhart and the Mt. General, fold and displace the distinctive stratigraphic units, as well as surficial late Pleistocene and Holocene deposits. The sedimentary architecture and the two fault zones provide a framework for evaluating groundwater flow in Hinkley Valley.

Trend analyses with river sediment rating curves

USGS Publications Warehouse

Warrick, Jonathan A.

2015-01-01

Sediment rating curves, which are fitted relationships between river discharge (Q) and suspended-sediment concentration (C), are commonly used to assess patterns and trends in river water quality. In many of these studies it is assumed that rating curves have a power-law form (i.e., C = aQb, where a and b are fitted parameters). Two fundamental questions about the utility of these techniques are assessed in this paper: (i) How well to the parameters, a and b, characterize trends in the data? (ii) Are trends in rating curves diagnostic of changes to river water or sediment discharge? As noted in previous research, the offset parameter, a, is not an independent variable for most rivers, but rather strongly dependent on b and Q. Here it is shown that a is a poor metric for trends in the vertical offset of a rating curve, and a new parameter, â, as determined by the discharge-normalized power function [C = â (Q/QGM)b], where QGM is the geometric mean of the Q values sampled, provides a better characterization of trends. However, these techniques must be applied carefully, because curvature in the relationship between log(Q) and log(C), which exists for many rivers, can produce false trends in â and b. Also, it is shown that trends in â and b are not uniquely diagnostic of river water or sediment supply conditions. For example, an increase in â can be caused by an increase in sediment supply, a decrease in water supply, or a combination of these conditions. Large changes in water and sediment supplies can occur without any change in the parameters, â and b. Thus, trend analyses using sediment rating curves must include additional assessments of the time-dependent rates and trends of river water, sediment concentrations, and sediment discharge.

Legacy effects of colonial millponds on floodplain sedimentation, bank erosion, and channel morphology, MID-Atlantic, USA

USGS Publications Warehouse

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

2009-01-01

Many rivers and streams of the Mid-Atlantic Region, United States (U.S.) have been altered by postcolonial floodplain sedimentation (legacy sediment) associated with numerous milldams. Little Conestoga Creek, Pennsylvania, a tributary to the Susquehanna River and the Chesapeake Bay, is one of these streams. Floodplain sedimentation rates, bank erosion rates, and channel morphology were measured annually during 2004-2007 at five sites along a 28-km length of Little Conestoga Creek with nine colonial era milldams (one dam was still in place in 2007). This study was part of a larger cooperative effort to quantify floodplain sedimentation, bank erosion, and channel morphology in a high sediment yielding region of the Chesapeake Bay watershed. Data from the five sites were used to estimate the annual volume and mass of sediment stored on the floodplain and eroded from the banks for 14 segments along the 28-km length of creek. A bank and floodplain reach based sediment budget (sediment budget) was constructed for the 28 km by summing the net volume of sediment deposited and eroded from each segment. Mean floodplain sedimentation rates for Little Conestoga Creek were variable, with erosion at one upstream site (-5 mm/year) to deposition at the other four sites (highest = 11 mm/year) despite over a meter of floodplain aggradation from postcolonial sedimentation. Mean bank erosion rates range between 29 and 163 mm/year among the five sites. Bank height increased 1 m for every 10.6 m of channel width, from upstream to downstream (R2 = 0.79, p < 0.0001) resulting in progressively lowered hydraulic connectivity between the channel and the floodplain. Floodplain sedimentation and bank erosion rates also appear to be affected by the proximity of the segments to one existing milldam, which promotes deposition upstream and scouring downstream. The floodplain and bank along the 28-km reach produced a net mean sediment loss of 5,634 Mg/year for 2004-2007, indicating that bank erosion was exceeding floodplain sedimentation. In particular, the three segments between the existing dam and the confluence with the Conestoga River (32% of the studied reach) account for 97% of the measured net sediment budget. Future research directed at understanding channel equilibria should facilitate efforts to reduce the sediment impacts of dam removal and legacy sediment. ?? 2009 American Water Resources Association.

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

PubMed

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

2015-02-01

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

Regional distribution of mercury in sediments of the main rivers of French Guiana (Amazonian basin).

PubMed

Laperche, Valérie; Hellal, Jennifer; Maury-Brachet, Régine; Joseph, Bernard; Laporte, Pierre; Breeze, Dominique; Blanchard, François

2014-01-01

Use of mercury (Hg) for gold-mining in French Guiana (up until 2006) as well as the presence of naturally high background levels in soils, has led to locally high concentrations in soils and sediments. The present study maps the levels of Hg concentrations in river sediments from five main rivers of French Guiana (Approuague River, Comté River, Mana River, Maroni River and Oyapock River) and their tributaries, covering more than 5 450 km of river with 1 211 sampling points. The maximum geological background Hg concentration, estimated from 241 non-gold-mined streams across French Guiana was 150 ng g(-1). Significant differences were measured between the five main rivers as well as between all gold-mining and pristine areas, giving representative data of the Hg increase due to past gold-mining activities. These results give a unique large scale vision of Hg contamination in river sediments of French Guiana and provide fundamental data on Hg distribution in pristine and gold-mined areas.

Owyhee River intracanyon lava flows: does the river give a dam?

USGS Publications Warehouse

Ely, Lisa L.; Brossy, Cooper C.; House, P. Kyle; Safran, Elizabeth B.; O'Connor, Jim E.; Champion, Duane E.; Fenton, Cassandra R.; Bondre, Ninad R.; Orem, Caitlin A.; Grant, Gordon E.; Henry, Christopher D.; Turrin, Brent D.

2013-01-01

Rivers carved into uplifted plateaus are commonly disrupted by discrete events from the surrounding landscape, such as lava flows or large mass movements. These disruptions are independent of slope, basin area, or channel discharge, and can dominate aspects of valley morphology and channel behavior for many kilometers. We document and assess the effects of one type of disruptive event, lava dams, on river valley morphology and incision rates at a variety of time scales, using examples from the Owyhee River in southeastern Oregon. Six sets of basaltic lava flows entered and dammed the river canyon during two periods in the late Cenozoic ca. 2 Ma–780 ka and 250–70 ka. The dams are strongly asymmetric, with steep, blunt escarpments facing up valley and long, low slopes down valley. None of the dams shows evidence of catastrophic failure; all blocked the river and diverted water over or around the dam crest. The net effect of the dams was therefore to inhibit rather than promote incision. Once incision resumed, most of the intracanyon flows were incised relatively rapidly and therefore did not exert a lasting impact on the river valley profile over time scales >106 yr. The net long-term incision rate from the time of the oldest documented lava dam, the Bogus Rim lava dam (≤1.7 Ma), to present was 0.18 mm/yr, but incision rates through or around individual lava dams were up to an order of magnitude greater. At least three lava dams (Bogus Rim, Saddle Butte, and West Crater) show evidence that incision initiated only after the impounded lakes filled completely with sediment and there was gravel transport across the dams. The most recent lava dam, formed by the West Crater lava flow around 70 ka, persisted for at least 25 k.y. before incision began, and the dam was largely removed within another 35 k.y. The time scale over which the lava dams inhibit incision is therefore directly affected by both the volume of lava forming the dam and the time required for sediment to fill the blocked valley. Variations in this primary process of incision through the lava dams could be influenced by additional independent factors such as regional uplift, drainage integration, or climate that affect the relative base level, discharge, and sediment yield within the watershed. By redirecting the river, tributaries, and subsequent lava flows to different parts of the canyon, lava dams create a distinct valley morphology of flat, broad basalt shelves capping steep cliffs of Tertiary sediment. This stratigraphy is conducive to landsliding and extends the effects of intracanyon lava flows on channel geomorphology beyond the lifetime of the dams.

Distributions, Early Diagenesis, and Spatial Characteristics of Amino Acids in Sediments of Multi-Polluted Rivers: A Case Study in the Haihe River Basin, China.

PubMed

Zhao, Yu; Shan, Baoqing; Tang, Wenzhong; Zhang, Hong; Rong, Nan; Ding, Yuekui

2016-02-19

The Haihe River Basin, which is one of the most water-scarce and polluted river basins in China, has abnormally high nitrogen levels. In this study, total hydrolyzable amino acids (THAAs) were measured in surface sediment and sediment core samples in the Haihe River Basin to determine if amino acids were potential sources of ammonium, organic nitrogen, and organic carbon. The rivers were found to be in a state of hypoxia and contain abnormally high levels of ammonium and organic nitrogen. Additionally, NH₃-N was the predominant form of inorganic nitrogen in the surface sediments, while organic nitrogen accounted for 92.53% of sedimentary nitrogen. THAAs-C accounted for 14.92% of the total organic carbon, while THAAs-N accounted for more than 49.59% of organic nitrogen and 45.68% of total nitrogen. The major fraction of THAAs were protein amino acids. Three sediment cores of the most heavily polluted rivers also showed high levels of THAAs. Evaluation of the degradation index (DI) of sedimentary organic matter in sediments evaluated based on the THAAs revealed that most positive DI values were found in the downstream portion of the Ziya River Watershed. Additionally, the DI of surface sediment was correlated with THAAs (r² = 0.763, p < 0.001), as was the DI of sediment cores (r² = 0.773, p < 0.001). Overall, amino acids in sediments were found to be an important potential source of ammonium, organic nitrogen, and organic carbon.

Distributions, Early Diagenesis, and Spatial Characteristics of Amino Acids in Sediments of Multi-Polluted Rivers: A Case Study in the Haihe River Basin, China

PubMed Central

Zhao, Yu; Shan, Baoqing; Tang, Wenzhong; Zhang, Hong; Rong, Nan; Ding, Yuekui

2016-01-01

The Haihe River Basin, which is one of the most water-scarce and polluted river basins in China, has abnormally high nitrogen levels. In this study, total hydrolyzable amino acids (THAAs) were measured in surface sediment and sediment core samples in the Haihe River Basin to determine if amino acids were potential sources of ammonium, organic nitrogen, and organic carbon. The rivers were found to be in a state of hypoxia and contain abnormally high levels of ammonium and organic nitrogen. Additionally, NH3-N was the predominant form of inorganic nitrogen in the surface sediments, while organic nitrogen accounted for 92.53% of sedimentary nitrogen. THAAs-C accounted for 14.92% of the total organic carbon, while THAAs-N accounted for more than 49.59% of organic nitrogen and 45.68% of total nitrogen. The major fraction of THAAs were protein amino acids. Three sediment cores of the most heavily polluted rivers also showed high levels of THAAs. Evaluation of the degradation index (DI) of sedimentary organic matter in sediments evaluated based on the THAAs revealed that most positive DI values were found in the downstream portion of the Ziya River Watershed. Additionally, the DI of surface sediment was correlated with THAAs (r2 = 0.763, p < 0.001), as was the DI of sediment cores (r2 = 0.773, p < 0.001). Overall, amino acids in sediments were found to be an important potential source of ammonium, organic nitrogen, and organic carbon. PMID:26907310

Geomorphic status of regulated rivers in the Iberian Peninsula.

PubMed

Lobera, G; Besné, P; Vericat, D; López-Tarazón, J A; Tena, A; Aristi, I; Díez, J R; Ibisate, A; Larrañaga, A; Elosegi, A; Batalla, R J

2015-03-01

River regulation by dams modifies flow regimes, interrupts the transfer of sediment through channel networks, and alters downstream bed dynamics, altogether affecting channel form and processes. So far, most studies on the geomorphic impacts of dams are restricted to single rivers, or even single river stretches. In this paper we analyse the geomorphic status of 74 river sites distributed across four large basins in the Iberian Peninsula (i.e. 47 sites located downstream of dams). For this purpose, we combine field data with hydrological data available from water agencies, and analyse historical (1970) and current aerial photographs. In particular, we have developed a Geomorphic Status (GS) index that allows us to assess the physical structure of a given channel reach and its change through time. The GS encompasses a determination of changes in sedimentary units, sediment availability, bar stability and channel flow capacity. Sites are statistically grouped in four clusters based on contrasted physical and climate characteristics. Results emphasise that regulation changes river's flow regime with a generalized reduction of the magnitude and frequency of floods (thus flow competence). This, in addition to the decrease downstream sediment supply, results in the loss of active bars as they are encroached by vegetation, to the point that only reaches with little or no regulation maintain exposed sedimentary deposits. The GS of regulated river reaches is negatively correlated with magnitude of the impoundment (regulation). Heavily impacted reaches present channel stabilization and, in contrast to the hydrological response, the distance and number of tributaries do not reverse the geomorphic impact of the dams. Stabilization limits river dynamics and may contribute to the environmental degradation of the fluvial ecosystem. Overall, results describe the degree of geomorphological alteration experienced by representative Iberian rivers mostly because of regulation, challenging the successful long-term implementation of river basin management programmes. Copyright © 2014 Elsevier B.V. All rights reserved.

A modeling study of the impacts of Mississippi River diversion and sea-level rise on water quality of a deltaic estuary

USGS Publications Warehouse

Wang, Hongqing; Chen, Qin; Hu, Kelin; LaPeyre, Megan K.

2017-01-01

Freshwater and sediment management in estuaries affects water quality, particularly in deltaic estuaries. Furthermore, climate change-induced sea-level rise (SLR) and land subsidence also affect estuarine water quality by changing salinity, circulation, stratification, sedimentation, erosion, residence time, and other physical and ecological processes. However, little is known about how the magnitudes and spatial and temporal patterns in estuarine water quality variables will change in response to freshwater and sediment management in the context of future SLR. In this study, we applied the Delft3D model that couples hydrodynamics and water quality processes to examine the spatial and temporal variations of salinity, total suspended solids, and chlorophyll-α concentration in response to small (142 m3 s−1) and large (7080 m3 s−1) Mississippi River (MR) diversions under low (0.38 m) and high (1.44 m) relative SLR (RSLR = eustatic SLR + subsidence) scenarios in the Breton Sound Estuary, Louisiana, USA. The hydrodynamics and water quality model were calibrated and validated via field observations at multiple stations across the estuary. Model results indicate that the large MR diversion would significantly affect the magnitude and spatial and temporal patterns of the studied water quality variables across the entire estuary, whereas the small diversion tends to influence water quality only in small areas near the diversion. RSLR would also play a significant role on the spatial heterogeneity in estuary water quality by acting as an opposite force to river diversions; however, RSLR plays a greater role than the small-scale diversion on the magnitude and spatial pattern of the water quality parameters in this deltaic estuary.

Long-term ongoing impact of arsenic contamination on the environmental compartments of a former mining-metallurgy area.

PubMed

González-Fernández, B; Rodríguez-Valdés, E; Boente, C; Menéndez-Casares, E; Fernández-Braña, A; Gallego, J R

2018-01-01

Arsenic and mercury are potentially toxic elements of concern for soil, surficial and ground waters, and sediments. In this work various geochemical and hydrogeological tools were used to study a paradigmatic case of the combined effects of the abandonment of Hg- and As-rich waste on these environmental compartments. Continuous weathering of over 40years has promoted As and Hg soil pollution (thousands of ppm) in the surroundings of a former Hg mining-metallurgy site and affected the water quality of a nearby river and shallow groundwater. In particular, the high availability of As both in soils and waste was identified as one of the main determinants of contaminant distribution, whereas the impact of Hg was found to be minor, which is explained by lower mobility. Furthermore, potential additional sources of pollution (coal mining, high natural backgrounds, etc.) discharging into the study river were revealed less significant than the contaminants generated in the Hg-mining area. The transport and deposition of pollutants within the water cycle has also affected several kilometres downstream of the release areas and the chemistry of stream sediments. Overall, the environmental compartments studies held considerable concentrations of Hg and As, as remarkably revealed by the average contaminant load released in the river (several tons of As per year) and the accumulation of toxic elements in sediments (enrichment factors of As and Hg above 35). Copyright © 2017 Elsevier B.V. All rights reserved.

Feeding the hungry river: Fluvial morphodynamics and the entrainment of artificially inserted sediment at the dammed river Isar, Eastern Alps, Germany

NASA Astrophysics Data System (ADS)

Heckmann, Tobias; Haas, Florian; Abel, Judith; Rimböck, Andreas; Becht, Michael

2017-08-01

Dams interrupt the sediment continuum in rivers by retaining the bedload; combined with flow diversion, bedload retention in tributaries and river engineering measures, this causes a bedload deficit leading to changes in river planform and morphodynamics, with potentially detrimental downstream effects. As part of the SedAlp joint project (Sediment management in Alpine basins: integrating sediment continuum, risk mitigation and hydropower), this study investigates changes within a section of the dammed river Isar between the Sylvenstein reservoir and the city of Bad Tölz. We use a multi-method approach on a range of spatial and temporal scales. First, we analysed historical maps and aerial photos to analyse river planform and landcover changes within the river corridor of the whole study area on a temporal scale of over 100 years. Results show that major changes occurred before the construction of the Sylvenstein reservoir, suggesting that present morphodynamics represent the reaction to different disturbances on different time scales. Second, changes in mean bed elevation of cross profiles regularly surveyed by the water authorities are analysed in light of artificial sediment insertion and floods; they are also used to estimate the sediment budget of river reaches between consecutive cross profiles. Results suggest stability and a slight tendency towards incision, especially near the Sylvenstein reservoir; further downstream, the sediment balance was positive. Third, we acquired multitemporal aerial photos using an unmanned aerial vehicle and generated high-resolution digital elevation models to show how sediment artificially inserted in the river corridor is entrained. Depending on the position of the artificial deposits in relation to the channel, the deposits are entrained during floods of different return periods.

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

Linking hysteresis patterns and variations in suspended sediment sources in a highly urbanized river: a case of the River Aire, UK

NASA Astrophysics Data System (ADS)

Vercruysse, Kim; Grabowski, Robert

2017-04-01

The natural sediment balance of rivers is often disturbed as a result of increased fine sediment influx from soil erosion and/or modifications to the river channel and floodplains, causing numerous problems related to ecology, water quality, flood risk and infrastructure. It is of great importance to understand fine sediment dynamics in rivers in order to manage the problems appropriately. However, despite decades of research, our understanding of fine sediment transport is not yet sufficient to fully explain the spatial and temporal variability in sediment concentrations in rivers. To this end, the study aims to investigate the importance of sediment source variations to explain hysteresis patterns in suspended sediment transport. A sediment fingerprinting technique based on infrared spectrometry was applied in the highly urbanized River Aire catchment in northern England to identify the dominant sources of suspended sediment. Three types of potential sediment source samples were collected: soil samples from pasture in three lithological areas (limestone, millstone grit and coal measures), eroding riverbanks and urban street dust. All source samples were analyzed with Diffuse Reflectance Infrared Fourier Transform spectrometry (DRIFTS). Discriminant analysis demonstrated that the source materials could be discriminated based on their respective infrared spectra. Infrared spectra of experimental mixtures were then used to develop statistical models to estimate relative source contributions from suspended sediment samples. Suspended sediment samples were collected during a set of high flow events between 2015 and 2016, showing different hysteresis patterns between suspended sediment concentration and discharge. The fingerprinting results suggest that pasture from the limestone area is the dominant source of fine sediment. However, significant variations in source contributions during and between events are present. Small events, in terms of discharge, are marked by relatively high contributions of urban street dust, while high stream flows correspond with higher sediment contributions from riverbanks and pasture. Seasonal variations in the dominant sources are also present. The results emphasize the importance of capturing sediment source variations to gain better insights into the drivers of fine sediment transport over various timescales.

Morphodynamic Modeling of the Lower Yellow River, China: Flux (Equilibrium) Form or Entrainment (Nonequilibrium) Form of Sediment Mass Conservation?

NASA Astrophysics Data System (ADS)

An, C.; Parker, G.; Ma, H.; Naito, K.; Moodie, A. J.; Fu, X.

2017-12-01

Models of river morphodynamics consist of three elements: (1) a treatment of flow hydraulics, (2) a formulation relating some aspect of sediment transport to flow hydraulics, and (3) a description of sediment conservation. In the case of unidirectional river flow, the Exner equation of sediment conservation is commonly described in terms of a flux-based formulation, in which bed elevation variation is related to the streamwise gradient of sediment transport rate. An alternate formulation of the Exner equation, however, is the entrainment-based formulation in which bed elevation variation is related to the difference between the entrainment rate of bed sediment into suspension and the deposition rate of suspended sediment onto the bed. In the flux-based formulation, sediment transport is regarded to be in a local equilibrium state (i.e., sediment transport rate locally equals sediment transport capacity). However, the entrainment-based formulation does not require this constraint; the sediment transport rate may lag in space and time behind the changing flow conditions. In modeling the fine-grained Lower Yellow River, it is usual to treat sediment conservation in terms of an entrainment-based (nonequilibrium) rather than a flux-based (equilibrium) formulation with the consideration that fine-grained sediment may be entrained at one place but deposited only at some distant location downstream. However, the differences in prediction between the two formulations are still not well known, and the entrainment formulation may not always be necessary for the Lower Yellow River. Here we study this problem by comparing the results of flux-based and entrainment-based morphodynamics under conditions typical of the Yellow River, using sediment transport equations specifically designed for the Lower Yellow River. We find, somewhat unexpectedly, that in a treatment of a 200-km reach using uniform sediment, there is little difference between the two formulations unless the sediment fall velocity is arbitrarily greatly reduced. A consideration of sediment mixtures, however, shows that the two formulations give very different patterns of grain sorting. We explain this in terms of the structures of the two Exner equations for sediment mixtures, and define conditions for applicability of each formulation.