Coastal Wetlands and Sediments of the San Francisco Bay System
Author :
Publisher :
Page : 2 pages
File Size : 39,35 MB
Release : 1994
Category : Dredging spoil
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Author :
Publisher :
Page : 2 pages
File Size : 39,35 MB
Release : 1994
Category : Dredging spoil
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Author :
Publisher :
Page : 1 pages
File Size : 35,21 MB
Release : 1994
Category : Dredging spoil
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Author :
Publisher :
Page : 2 pages
File Size : 11,66 MB
Release : 1994
Category : Dredging spoil
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Author : Scott Dusterhoff
Publisher :
Page : 148 pages
File Size : 47,19 MB
Release : 2021-05
Category :
ISBN : 9781950313068
The resilience of San Francisco Bay shore habitats, such as tidal marshes and mudflats, is essential to all who live in the Bay Area. Tidal marshes and tidal flats (also known as mudflats) are key components of the shore habitats, collectively called baylands, which protect billions of dollars of bay-front housing and infrastructure (including neighborhoods, business parks, highways, sewage treatment plants, and landfills). They purify the Bay's water, support endangered wildlife, nurture fisheries, and provide people access to nature within the urban environment. Bay Area residents showed their commitment to restoring these critical habitats when they voted for a property tax to pay for large-scale tidal marsh restoration. However, climate change poses a great threat, because there may not be enough natural sediment supply for tidal marshes and mudflats to gain elevation fast enough to keep pace with sea-level rise. This report analyses current data and climate projections to determine how much natural sediment may be available for tidal marshes and mudflats and how much supplemental sediment may be needed under different future scenarios. These sediment supply and demand estimates are combined with scientific knowledge of natural physical and biological processes to offer a strategy for sediment delivery that will allow these wetlands to survive a changing climate and provide benefits to people and nature for many decades to come. The approach developed in this report may also be useful beyond San Francisco Bay because shoreline protection, flood risk-management, and looming sediment deficits are common issues facing coastal communities around the world.
Author : Geological Survey (U.S.)
Publisher :
Page : 94 pages
File Size : 23,89 MB
Release : 1990
Category : Coast changes
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Tracings: 04.40, 76.84, 94.52, 94.82.
Author : Sheung Yan Sueann Lee
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Page : pages
File Size : 43,98 MB
Release : 2014
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ISBN :
The long-term evolution of shallow intertidal zones is of particular interest in light of efforts to restore coastal marshes. Factors that affect that rate of accretion or erosion of a marsh include current speeds, wind waves, tides and sediment load. These forcings change with time and vary on different time scales, and for any particular marsh the importance of each forcing may be different. Observations indicate that shallow intertidal basins tend to be characterized by a bimodal distribution of water depths into higher marshplain and lower mudflats. For shallow intertidal marshes, wind waves and tidal currents would both affect the deposition and erosion of sediments. It is hypothesized that for a shallow intertidal marsh with significant wind effects, wind waves will cause increased turbulence that enhances resuspension of sediment, leading to lower mudflats rather than higher marshplains. In this project, an attempt is made to study the factors that affect sediment deposition and resuspension, and the variability of these factors with time. Field data was collected for two weeks at a tidal wetlands restoration site, the Sonoma Baylands, California. Two locations within the field site with different wind fetches are compared to show the impact of wind on turbidity. At each site, wind speed, current velocity, wave, and turbidity data was collected. Turbidity is used as a proxy for suspended sediment concentration. Relative wave height and wave shear stress were found to be most correlated with turbidity. At the site with shorter fetch, current shear stress was almost as important as wave shear stress, but it was not significantly correlated at the site with longer fetch and larger waves. The importance of wind waves for sediment will help develop understanding of the mechanisms and factors affecting the transition of a shallow coastal region into either a marshplain accreting to mean high-high water level, or eroding into mudflat. The results of this study will be useful in determining the importance of wind waves on sedimentation, thus helping in developing strategies for restoring or protecting tidal marshes. To further study the process of sediment transport in San Francisco Bay, a three-dimensional coupled hydrodynamic, wind wave and mud suspension model SUNTANS was developed. The model was calibrated to existing meteorological, current, salinity, wave and sediment conditions. The model was found to be in general agreement with existing patterns of salinity, wave and sediment distribution. Higher sediment concentrations were generally found in locations of higher wind, shallow depths, complicated bathymetry, and/or down wind locations, in line with the established understanding of wind-induced sediment resuspension together with current induced erosion and advective transport.
Author : Bernard J. Smith
Publisher :
Page : 18 pages
File Size : 47,40 MB
Release : 1966
Category : Marine sediments
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Author : United States. Army. Corps of Engineers
Publisher :
Page : 174 pages
File Size : 35,58 MB
Release : 1963
Category : San Francisco Bay (Calif.)
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Author :
Publisher :
Page : 80 pages
File Size : 11,76 MB
Release : 1994
Category : Aquatic ecology
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Page : 280 pages
File Size : 46,54 MB
Release : 1991
Category : Estuarine ecology
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