Correction factors for estimating suspended sediment export from loess catchments

2001 ◽  
Vol 26 (4) ◽  
pp. 441-449 ◽  
Author(s):  
A. Steegen ◽  
G. Govers
Keyword(s):  
Suspended Sediment ◽  
Correction Factors ◽  
Sediment Export

Contrasting suspended sediment export in two small agricultural catchments: Cross-influence of hydrological behaviour and landscape degradation or stream bank management

2018 ◽  
Vol 29 (5) ◽  
pp. 1385-1396 ◽  
Author(s):  
Amphone Vongvixay ◽  
Catherine Grimaldi ◽  
Rémi Dupas ◽  
Ophélie Fovet ◽  
François Birgand ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Agricultural Catchments ◽  
Landscape Degradation ◽  
Bank Management ◽  
Stream Bank ◽  
Sediment Export

scholarly journals Quantifying total suspended sediment export from the Burdekin River catchment using the loads regression estimator tool

2012 ◽  
Vol 48 (4) ◽  
Author(s):  
Petra M. Kuhnert ◽  
Brent L. Henderson ◽  
Stephen E. Lewis ◽  
Zoe T. Bainbridge ◽  
Scott N. Wilkinson ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Regression Estimator ◽  
Total Suspended Sediment ◽  
River Catchment ◽  
Sediment Export

scholarly journals Temperature signal in suspended sediment export from an Alpine catchment

2018 ◽  
Vol 22 (1) ◽  
pp. 509-528 ◽  
Author(s):  
Anna Costa ◽  
Peter Molnar ◽  
Laura Stutenbecker ◽  
Maarten Bakker ◽  
Tiago A. Silva ◽  
...  
Keyword(s):  
Snow Cover ◽  
Suspended Sediment ◽  
Air Temperature ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Sediment Sources ◽  
Free Surfaces ◽  
Ice Melt ◽  
Alpine Catchments ◽  
Sediment Export

Abstract. Suspended sediment export from large Alpine catchments (> 1000 km2) over decadal timescales is sensitive to a number of factors, including long-term variations in climate, the activation–deactivation of different sediment sources (proglacial areas, hillslopes, etc.), transport through the fluvial system, and potential anthropogenic impacts on the sediment flux (e.g. through impoundments and flow regulation). Here, we report on a marked increase in suspended sediment concentrations observed near the outlet of the upper Rhône River Basin in the mid-1980s. This increase coincides with a statistically significant step-like increase in basin-wide mean air temperature. We explore the possible explanations of the suspended sediment rise in terms of changes in water discharge (transport capacity), and the activation of different potential sources of fine sediment (sediment supply) in the catchment by hydroclimatic forcing. Time series of precipitation and temperature-driven snowmelt, snow cover, and ice melt simulated with a spatially distributed degree-day model, together with erosive rainfall on snow-free surfaces, are tested to explore possible reasons for the rise in suspended sediment concentration. We show that the abrupt change in air temperature reduced snow cover and the contribution of snowmelt, and enhanced ice melt. The results of statistical tests show that the onset of increased ice melt was likely to play a dominant role in the suspended sediment concentration rise in the mid-1980s. Temperature-driven enhanced melting of glaciers, which cover about 10 % of the catchment surface, can increase suspended sediment yields through an increased contribution of sediment-rich glacial meltwater, increased sediment availability due to glacier recession, and increased runoff from sediment-rich proglacial areas. The reduced extent and duration of snow cover in the catchment are also potential contributors to the rise in suspended sediment concentration through hillslope erosion by rainfall on snow-free surfaces, and increased meltwater production on snow-free glacier surfaces. Despite the rise in air temperature, changes in mean discharge in the mid-1980s were not statistically significant, and their interpretation is complicated by hydropower reservoir management and the flushing operations at intakes. Overall, the results show that to explain changes in suspended sediment transport from large Alpine catchments it is necessary to include an understanding of the multitude of sediment sources involved together with the hydroclimatic conditioning of their activation (e.g. changes in precipitation, runoff, air temperature). In addition, this study points out that climate signals in suspended sediment dynamics may be visible even in highly regulated and human-impacted systems. This is particularly relevant for quantifying climate change and hydropower impacts on streamflow and sediment budgets in Alpine catchments.

scholarly journals FIELD INVESTIGATION OF SUSPENDED SEDIMENT IN THE SURF ZONE

2000 ◽  
Vol 1 (4) ◽  
pp. 11
Author(s):  
George M. Watts
Keyword(s):  
Suspended Sediment ◽  
Surf Zone ◽  
Field Tests ◽  
Field Investigation ◽  
Wave Action ◽  
Beach Erosion ◽  
Correction Factors ◽  
Suspended Material ◽  
Field Development ◽  
Laboratory Development

Purpose - This paper presents the results of a number of field observations made at Pacific Beach near San Diego, California with a suspended sediment sampler. A detailed description of the laboratory and field development of the sampler is presented in the Beach Erosion Board Technical Memorandum Ho. 3k entitled "Development and Field Tests of a Sampler for Suspended Sediment in Wave Action". The laboratory development involved: a circulating system which provided various current velocities and concentration patterns at the test section; the testing of various size nozzles; the study of particle size distribution of samples obtained by the nozzles; and the development of correction factors for field conditions. It was concluded from the laboratory study that a pump-type sampler could be adapted to the study of suspended material movement in wave action. The principal result from the laboratory tests was a tentative finding that by pumping through a vertically disposed 1/2-inch nozzle with a velocity approximately twice the maximum orbital current velocity in a wave, samples could be obtained which were representative in weight (even without a correction factor) to within about 15 per cent of the true suspension.

Few floods govern decades of suspended sediment flux in German upland rivers

2021 ◽  
Author(s):  
Jan Henrik Blöthe ◽  
Thomas Hoffmann
Keyword(s):  
Suspended Sediment ◽  
Sediment Yield ◽  
Water Discharge ◽  
Sediment Flux ◽  
Spatiotemporal Variability ◽  
Suspended Sediment Transport ◽  
Sediment Yields ◽  
Suspended Sediment Flux ◽  
Event Flow ◽  
Sediment Export

<p>Sediment yield from lowland rivers around the globe is often dominated by suspended sediment that also acts as a carrier for pollutants and contaminants. Achieving a deeper understanding of the suspended sediment dynamics is important for river management, but often complicated by short or discontinuous time-series and scattered surveying locations. However, suspended sediment transport is highly variable in space and time, calling for decadal observations that reflect this variability. Here we make use of >130,000 measurements on water discharge (Q) and suspended sediment concentration (SSC) from twelve stations that drain large parts of the central German uplands, to investigate the spatiotemporal variability in suspended sediment flux. <br>The data has been collected during working days between 1965 and 2018 in context of the suspended sediment monitoring conducted by the Federal Waterways and Shipping Administration (WSV). The contributing catchments of the twelve monitoring stations range between 2500 and 22000 km<sup>2</sup> and cover observation periods between 27 and 53 years. <br>Despite roughly similar topographic and climatic conditions, average specific (suspended) sediment yield (SSY) varies between ~6 and ~29 t km<sup>2</sup> yr<sup>-1</sup>. Highest specific yields are observed for those catchments that drain the escarpment of the Swabian cuesta landscape. Even more pronounced than the spatial variability is the interannual variability in sediment yield, with SSY for very wet years exceeding SSY for dry years more than tenfold. Separating the hydrograph into base-flow and event-flow components, we find that sediment export during event-flows accounts for 60 to 85% of the long-term SSY, with individual floods accounting for more than 90% of the annual sediment export. We conclude that high specific (suspended) sediment yields in the central German uplands are conditioned by rapidly responding catchments (i.e. large fraction of event-flow contribution) with highly erodible lithologies of the Swabian cuesta landscapes.</p>

scholarly journals Temperature signal in suspended sediment export from an Alpine catchment

2017 ◽  
Author(s):  
Anna Costa ◽  
Peter Molnar ◽  
Laura Stutenbecker ◽  
Maarten Bakker ◽  
Tiago A. Silva ◽  
...  
Keyword(s):  
Snow Cover ◽  
Suspended Sediment ◽  
Air Temperature ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Sediment Supply ◽  
Free Surfaces ◽  
Ice Melt ◽  
Alpine Catchments ◽  
Sediment Export

Abstract. Suspended sediment export from large Alpine catchments (> 1000 km2) over decadal timescales is sensitive to a number of factors, including long–term variations in climate, the activation–deactivation of different sediment sources (proglacial areas, hillslopes, etc.), transport through the river system, and potential anthropogenic impacts on the sediment flux (e.g. through impoundments and flow regulation). Here, we report on a marked increase in suspended sediment concentrations observed close to the outlet of the upper Rhône River Basin in the mid–1980s. This increase coincides with a statistically significant step–like increase in basin–wide mean air temperature. We explore the potential explanations of the suspended sediment rise in terms of discharge (transport capacity) change, and the activation of different sources of fine sediment (sediment supply) in the catchment by hydroclimatic forcing. Time series of precipitation and temperature–driven snowmelt, snow cover and ice–melt simulated with a spatially distributed degree–day model, together with erosive rainfall on snow–free surfaces, are tested as possible reasons for the rise in suspended sediment concentration. We demonstrate that the abrupt change in air temperature reduced snow cover and the contribution of snowmelt, and enhanced ice–melt. The results of statistical tests showed that the onset of increased ice–melt was likely to play a dominant role in the suspended sediment concentration rise in the mid–1980s. Temperature–driven enhanced melting of glaciers, which cover about 10 % of the catchment surface, can increase suspended sediment yields through increased runoff from sediment–rich proglacial areas, increased contribution of sediment–rich meltwater, and increased sediment supply in proglacial areas due to glacier recession. The reduced extent and duration of snow cover in the catchment may also have partly contributed to the rise in suspended sediment concentration through hillslope erosion by rainfall on snow free surfaces, and by reducing snow cover on the surface of the glaciers and thereby increasing meltwater production. Despite the rise in air temperature, changes in mean discharge in the mid–1980s were statistically insignificant, and their interpretation is complicated by hydropower reservoir management and the flushing operations at intakes. Thus, the results show that to explain changes in suspended sediment transport from large Alpine catchments it is necessary to include an understanding of the multitude of sediment sources involved together with the hydroclimatic conditioning of their activation (e.g. changes in precipitation, runoff, air temperature). This is particularly relevant for quantifying climate change and hydropower impacts on streamflow and sediment budgets in high Alpine catchments.

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