scholarly journals A 2-D process-based model for suspended sediment dynamics: a first step towards ecological modeling

2015 ◽  
Vol 12 (2) ◽  
pp. 1507-1553 ◽  
Author(s):  
F. M. Achete ◽  
M. van der Wegen ◽  
D. Roelvink ◽  
B. Jaffe
Keyword(s):  
Suspended Sediment ◽  
San Francisco ◽  
Complex Geometry ◽  
Current Model ◽  
Sediment Dynamics ◽  
Habitat Modeling ◽  
Sediment Supply ◽  
Model Parameters ◽  
Spatial And Temporal Scales ◽  
A Chain

Abstract. In estuaries most of the sediment load is carried in suspension. Sediment dynamics differ depending on sediment supply and hydrodynamic forcing conditions that vary over space and over time. Suspended sediment concentration (SSC) is one of the most important contributors to turbidity, which influences habitat conditions and ecological functions of the system. A robust sediment model is the first step towards a chain of model including contaminants and phytoplankton dynamics and habitat modeling. This works aims to determine turbidity levels in the complex-geometry Delta of San Francisco Estuary using a process-based approach (D-Flow Flexible Mesh software). Our approach includes a detailed calibration against measured SSC levels, a sensitivity analysis on model parameters, the determination of a yearly sediment budget as well as an assessment of model results in terms of turbidity levels for a single year (Water Year 2011). Model results shows that our process-based approach is a valuable tool in assessing sediment dynamics and their related ecological parameters over a range of spatial and temporal scales. The current model may act as the base model for a chain of ecological models and climate scenario forecasting.

scholarly journals A 2-D process-based model for suspended sediment dynamics: a first step towards ecological modeling

2015 ◽  
Vol 19 (6) ◽  
pp. 2837-2857 ◽  
Author(s):  
F. M. Achete ◽  
M. van der Wegen ◽  
D. Roelvink ◽  
B. Jaffe
Keyword(s):  
Suspended Sediment ◽  
San Francisco ◽  
Complex Geometry ◽  
Transport Model ◽  
Sediment Dynamics ◽  
Sediment Supply ◽  
Model Parameters ◽  
Habitat Conditions ◽  
A Chain ◽  
The Impact

Abstract. In estuaries suspended sediment concentration (SSC) is one of the most important contributors to turbidity, which influences habitat conditions and ecological functions of the system. Sediment dynamics differs depending on sediment supply and hydrodynamic forcing conditions that vary over space and over time. A robust sediment transport model is a first step in developing a chain of models enabling simulations of contaminants, phytoplankton and habitat conditions. This works aims to determine turbidity levels in the complex-geometry delta of the San Francisco estuary using a process-based approach (Delft3D Flexible Mesh software). Our approach includes a detailed calibration against measured SSC levels, a sensitivity analysis on model parameters and the determination of a yearly sediment budget as well as an assessment of model results in terms of turbidity levels for a single year, water year (WY) 2011. Model results show that our process-based approach is a valuable tool in assessing sediment dynamics and their related ecological parameters over a range of spatial and temporal scales. The model may act as the base model for a chain of ecological models assessing the impact of climate change and management scenarios. Here we present a modeling approach that, with limited data, produces reliable predictions and can be useful for estuaries without a large amount of processes data.

Suspended-sediment dynamics in the tidal reach of a San Francisco Bay tributary

2015 ◽  
Vol 65 (11) ◽  
pp. 1477-1488 ◽  
Author(s):  
Gregory G. Shellenbarger ◽  
Maureen A. Downing-Kunz ◽  
David H. Schoellhamer
Keyword(s):  
Suspended Sediment ◽  
San Francisco ◽  
San Francisco Bay ◽  
Sediment Dynamics ◽  
Tidal Reach

scholarly journals Suspended sediment and discharge dynamics in a glacierized alpine environment: Identifying crucial areas and time periods on several spatial and temporal scales in the Ötztal, Austria

2022 ◽  
Author(s):  
Lena Katharina Schmidt ◽  
Till Francke ◽  
Erwin Rottler ◽  
Theresa Blume ◽  
Johannes Schöber ◽  
...  
Keyword(s):  
Snow Cover ◽  
Suspended Sediment ◽  
Sediment Dynamics ◽  
Recent Sediment ◽  
Mass Balances ◽  
Temporal Scales ◽  
Spatial And Temporal Scales ◽  
Sediment Yields ◽  
Sediment Fluxes ◽  
Precipitation Events

Abstract. Climatic changes are expected to fundamentally alter discharge and sediment dynamics in glaciated high alpine areas, e.g. through glacier retreat, prolonged snow-free periods and more frequent intense rainfall events in summer. However, how exactly these hydrological changes will affect sediment dynamics is not yet known. In the present study, we aim to pinpoint areas and processes most relevant to recent sediment and discharge dynamics on different spatial and temporal scales in the Ötztal Alpine Region in Tyrol, Austria. Therefore, we analyze observed discharge and relatively long suspended sediment time series of up to 15 years from three gauges in a nested catchment setup. The catchments range from 100 to almost 800 km2 in size with 10 to 30 % glacier cover and span an elevation range of 930 to 3772 m a.s.l.. The investigation of satellite-based snow cover maps, glacier inventories, mass balances and precipitation data complement the analysis. Our results indicate that mean annual specific discharge and suspended sediment fluxes are highest in the most glaciated sub-catchment and both fluxes correlate significantly with annual glacier mass balances. Furthermore, both discharge and suspended sediment loads show a distinct seasonality with low values during winter and high values during summer. However, the spring onset of sediment transport is almost synchronous at the three gauges, contrary to the spring rise in discharge, which occurs earlier further downstream. A spatio-temporal analysis of snow cover evolution indicates that the spring increase in sediment fluxes at all gauges coincides with the onset of snow melt above 2500 m elevation. Zones above this elevation include glacier tongues and recently deglaciated areas, which seem to be crucial for the sediment dynamics in the catchment. Precipitation events in summer were associated with peak sediment concentrations and fluxes, but on average accounted for only 21 % of the annual sediment yields of the years 2011 to 2020. We conclude that glaciers and the areas above 2500 m elevation play a dominant role for discharge and sediment dynamics in the Ötztal area, while precipitation events play a secondary role. Our study extends the scientific knowledge on current hydro-sedimentological changes in glaciated high alpine areas and provides a baseline for investigations on projected future changes in hydro-sedimentological system dynamics.

THE INITIAL RESULTS OF THE SUSPENDED SEDIMENT DYNAMICS DURING THE DRY SEASON IN THE HAU RIVER MOUTH AREA

2017 ◽  
Vol 17 (2) ◽  
Author(s):  
Nguyen Ngoc Tien ◽  
Dinh Van Uu ◽  
Nguyen Tho Sao ◽  
Do Huy Cuong ◽  
Nguyen Trung Thanh ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
River Mouth ◽  
Dry Season ◽  
Sediment Dynamics ◽  
Mouth Area ◽  
River Mouth Area ◽  
Initial Results

scholarly journals Watershed Suspended Sediment Supply and Potential Impacts of Dam Removals for an Estuary

2021 ◽  
Author(s):  
David K. Ralston ◽  
Brian Yellen ◽  
Jonathan D. Woodruff
Keyword(s):  
Suspended Sediment ◽  
River Estuary ◽  
Dam Removal ◽  
Hudson River ◽  
Sediment Traps ◽  
Sediment Supply ◽  
Watershed Area ◽  
Natural Lakes ◽  
Sediment Deposits ◽  
Dam Removals

AbstractObservations and modeling are used to assess potential impacts of sediment releases due to dam removals on the Hudson River estuary. Watershed sediment loads are calculated based on sediment-discharge rating curves for gauges covering 80% of the watershed area. The annual average sediment load to the estuary is 1.2 Mt, of which about 0.6 Mt comes from side tributaries. Sediment yield varies inversely with watershed area, with regional trends that are consistent with substrate erodibility. Geophysical and sedimentological surveys in seven subwatersheds of the Lower Hudson were conducted to estimate the mass and composition of sediment trapped behind dams. Impoundments were classified as (1) active sediment traps, (2) run-of-river sites not actively trapping sediment, and (3) dammed natural lakes and spring-fed ponds. Based on this categorization and impoundment attributes from a dam inventory database, the total mass of impounded sediment in the Lower Hudson watershed is estimated as 4.9 ± 1.9 Mt. This represents about 4 years of annual watershed supply, which is small compared with some individual dam removals and is not practically available given current dam removal rates. More than half of dams impound drainage areas less than 1 km2, and play little role in downstream sediment supply. In modeling of a simulated dam removal, suspended sediment in the estuary increases modestly near the source during discharge events, but otherwise effects on suspended sediment are minimal. Fine-grained sediment deposits broadly along the estuary and coarser sediment deposits near the source, with transport distance inversely related to settling velocity.

Suspended sediment dynamics during the inter-monsoon season in the subaqueous Mekong Delta and adjacent shelf, southern Vietnam

2014 ◽  
Vol 79 ◽  
pp. 509-519 ◽  
Author(s):  
Daniel Unverricht ◽  
Thanh Cong Nguyen ◽  
Christoph Heinrich ◽  
Witold Szczuciński ◽  
Niko Lahajnar ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Monsoon Season ◽  
Mekong Delta ◽  
Sediment Dynamics ◽  
Southern Vietnam
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