scholarly journals Tidal Asymmetry in Ocean-Boundary Flux and In-Estuary Trapping of Suspended Sediment Following Watershed Storms: San Francisco Estuary, California, USA

2021 ◽  
Author(s):  
Maureen A. Downing-Kunz ◽  
Paul A. Work ◽  
David H. Schoellhamer
Keyword(s):  
Suspended Sediment ◽  
San Francisco ◽  
Sediment Resuspension ◽  
San Francisco Estuary ◽  
Sediment Flux ◽  
Golden Gate ◽  
Storm Events ◽  
Suspended Sediment Flux ◽  
Field Campaigns ◽  
Ocean Boundary

AbstractSuspended-sediment flux at the ocean boundary of the San Francisco Estuary—the Golden Gate—was measured over a tidal cycle following peak watershed runoff from storms to the estuary in two successive years to investigate sediment transport through the estuary. Observations were repeated during low-runoff conditions, for a total of three field campaigns. Boat-based measurements of velocity and acoustic backscatter were used to calculate water and suspended-sediment flux at a location 1 km landward of the Golden Gate. Suspended-sediment concentration (SSC) and salinity data from up-estuary sensors were used to track watershed-sourced sediment plumes through the estuary. Estimates of suspended-sediment load from the watershed and net suspended-sediment flux for one up-estuary subembayment were used to infer in-estuary trapping of sediment. For both post-storm field campaigns, observations at the ocean boundary were conducted on the receding limb of the watershed hydrograph. At the ocean boundary, peak instantaneous suspended-sediment flux was tidally asymmetric and was greater on flood tides than on ebb tides for all three field campaigns, due to higher average SSC in the cross-section on flood tides. Shear-induced sediment resuspension was greater on flood tides and suggests the presence of an erodible pool outside the estuary. The storms in 2016 led to less export of discharge and sediment from the watershed and greater sediment trapping within one up-estuary subembayment compared to that observed in 2017. Results suggest that substantial trapping of watershed sediments occurred during both storm events, likely due to the formation of estuarine turbidity maxima (ETM) at different locations in the estuary. ETM locations were forced nearer the ocean boundary in 2017. Additional measurements and modeling are required to quantify the long-term sediment flux at the Golden Gate.

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

Geomorphology ◽  
2013 ◽  
Vol 202 ◽  
pp. 128-139 ◽  
Author(s):  
P.N. Owens ◽  
T.R. Giles ◽  
E.L. Petticrew ◽  
M.S. Leggat ◽  
R.D. Moore ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Sediment Flux ◽  
Suspended Sediment Flux

scholarly journals Energy Dissipation During Subglacial Abrasion at Nisqually Glacier, Washington, U.S.A.

1979 ◽  
Vol 23 (89) ◽  
pp. 233-246 ◽  
Author(s):  
Richard C. Metcalf
Keyword(s):  
Energy Balance ◽  
Suspended Sediment ◽  
Water Flux ◽  
Gravitational Energy ◽  
Sediment Flux ◽  
Normal Stresses ◽  
Mount Rainier ◽  
Suspended Sediment Flux ◽  
Basal Sliding ◽  
Order Of Magnitude

AbstractThis study examines the effect of subglacial abrasion on the basal sliding term of the gravitational energy balance of the dynamic, temperate Nisqually Glacier on Mount Rainier, Washington, U.S.A. Subglacial water flux is estimated as 3 × 107 m3 a–1 and suspended sediment flux as 3 × 107 kg a–1. Suspended-sediment flux is assumed to represent, within an order of magnitude, the annual mass eroded by subglacial abrasion.Subglacial abrasion involves both brittle fracture and plastic deformation. Field observations of bas-relief and grooved depression striations appear to have exact counterparts in rock mechanics experiments approximating subglacial velocities and normal stresses. Boulton's ([Cl974]) abrasion model and a new attritivity model proposed herein are shown to predict subglacial abrasion-rates within the limits of natural variability and the error range of measurements. The first crude gravitational energy balance for lower Nisqually Glacier (1.96 km2) is attempted and probably has only order-of-magnitude accuracy. The importance of subglacial abrasion in dissipating basal sliding energy at Nisqually Glacier is confirmed.

scholarly journals Conceptual model of sedimentgraph from flood events in a small agricultural watershed

2008 ◽  
Vol 39 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Kazimierz Banasik ◽  
J. Mitchell
Keyword(s):  
Conceptual Model ◽  
Suspended Sediment ◽  
Sediment Concentration ◽  
Agricultural Watershed ◽  
Sediment Flux ◽  
Flood Events ◽  
Rainfall Events ◽  
Sediment Routing ◽  
Suspended Sediment Flux ◽  
Lag Times

Conceptual model of sedimentgraph from flood events in a small agricultural watershed A procedure for predicting the sediment graph (i.e. the suspended sediment flux), from a small river catchment by heavy rainfall, has been developed using the concept of an instantaneous unit hydrograph (IUH) and dimensionless sediment concentration distribution (DSCD). A formula for instantaneous unit sedimentgraph (IUSG) is presented, and a procedure for estimating the sediment routing coefficient, which is a key parameter of the IUSG, based on measured data of rainfall-runoff-suspended sediment is applied. Field data from a small, field sized agricultural basin, lacated in center of Illinois has been used for analizing lag times for runoff (LAG) and sediment yield (LAGs). Assumptions about sediment generated during rainfall events are discussed.

scholarly journals Climatic and geologic controls on suspended sediment flux in the Sutlej River Valley, western Himalaya

2012 ◽  
Vol 16 (7) ◽  
pp. 2193-2217 ◽  
Author(s):  
H. Wulf ◽  
B. Bookhagen ◽  
D. Scherler
Keyword(s):  
Water Quality ◽  
Suspended Sediment ◽  
Western Himalaya ◽  
Sediment Flux ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Hydropower Generation ◽  
Spatiotemporal Trends ◽  
Suspended Sediment Flux ◽  
Geologic Controls

Abstract. The sediment flux through Himalayan rivers directly impacts water quality and is important for sustaining agriculture as well as maintaining drinking-water and hydropower generation. Despite the recent increase in demand for these resources, little is known about the triggers and sources of extreme sediment flux events, which lower water quality and account for extensive hydropower reservoir filling and turbine abrasion. Here, we present a comprehensive analysis of the spatiotemporal trends in suspended sediment flux based on daily data during the past decade (2001–2009) from four sites along the Sutlej River and from four of its main tributaries. In conjunction with satellite data depicting rainfall and snow cover, air temperature and earthquake records, and field observations, we infer climatic and geologic controls of peak suspended sediment concentration (SSC) events. Our study identifies three key findings: First, peak SSC events (≥ 99th SSC percentile) coincide frequently (57–80%) with heavy rainstorms and account for about 30% of the suspended sediment flux in the semi-arid to arid interior of the orogen. Second, we observe an increase of suspended sediment flux from the Tibetan Plateau to the Himalayan Front at mean annual timescales. This sediment-flux gradient suggests that averaged, modern erosion in the western Himalaya is most pronounced at frontal regions, which are characterized by high monsoonal rainfall and thick soil cover. Third, in seven of eight catchments, we find an anticlockwise hysteresis loop of annual sediment flux variations with respect to river discharge, which appears to be related to enhanced glacial sediment evacuation during late summer. Our analysis emphasizes the importance of unconsolidated sediments in the high-elevation sector that can easily be mobilized by hydrometeorological events and higher glacial-meltwater contributions. In future climate change scenarios, including continuous glacial retreat and more frequent monsoonal rainstorms across the Himalaya, we expect an increase in peak SSC events, which will decrease the water quality and impact hydropower generation.

scholarly journals Hydro-meteorological drivers and sources of suspended sediment flux in the pro-glacial zone of the retreating Castle Creek Glacier, Cariboo Mountains, British Columbia, Canada

2015 ◽  
Vol 40 (11) ◽  
pp. 1542-1559 ◽  
Author(s):  
Michael S. Leggat ◽  
Philip N. Owens ◽  
Tim A. Stott ◽  
Barry J. Forrester ◽  
Stephen J. Déry ◽  
...  
Keyword(s):  
British Columbia ◽  
Suspended Sediment ◽  
Sediment Flux ◽  
Suspended Sediment Flux

Near bed suspended sediment flux by single turbulent events

2018 ◽  
Vol 152 ◽  
pp. 76-86 ◽  
Author(s):  
Seyed Mohammad Amirshahi ◽  
Eva Kwoll ◽  
Christian Winter
Keyword(s):  
Suspended Sediment ◽  
Sediment Flux ◽  
Suspended Sediment Flux
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