U.S. Geological Survey Open-File Report 2008-1347
Executive SummaryOcean Beach, California, contains an erosion hot spot in the shadow of the San Francisco ebb tidal delta that threatens valuable public infrastructure as well as the safe recreational use of the beach. In an effort to reduce the erosion at this location a new plan for the management of sediment dredged annually from the main shipping channel at the mouth of San Francisco Bay was implemented in May 2005 by the United States Army Corps of Engineers, San Francisco District (USACE). The USACE designated a temporary nearshore dredge disposal site for the annual disposal of about 230,000 m3 (300,000 yd3) of sand about 750 m offshore and slightly south of the erosion hot spot, in depths between approximately 9 and 14 m. The site has now been used three times for a total sediment disposal of about 690,000 m3 (about 900,000 yds3). The disposal site was chosen because it is in a location where strong tidal currents and open-ocean waves can potentially feed sediment toward the littoral zone in the reach of the beach that is experiencing critical erosion, as well as prevent further scour on an exposed outfall pipe. The onshore migration of sediment from the target disposal location might feed the primary longshore bar or the nearshore zone, and provide a buffer to erosion that peaks during winter months when large waves impact the region. The United States Geological Survey (USGS) has been monitoring and modeling the bathymetric evolution of the test dredge disposal site and the adjacent coastal region since inception in May 2005. This paper reports on the first 2.5 years of this monitoring program effort (May 2005 to December 2007) and assesses the short-term coastal response. Here are the key findings of this report:
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Posted March 16, 2009 For additional information contact: Western Coastal & Marine Geology This report is available only on the Web. Part or all of this report is presented in Portable Document Format (PDF); at least version 7 of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge. |
Barnard, P.L., Erikson, L.H., Hansen, J.E., and Elias, Edwin, 2009, The Performance of nearshore dredge disposal at Ocean Beach, San Francisco, California, 2005-2007: U.S. Geological Survey Open-File Report 2008-1347, 93 p. [https://pubs.usgs.gov/of/2008/1347/].
Executive Summary
Introduction
Objectives
Background
Methods
Results and Discussion
Conclusions
Acknowledgments
References Cited
Appendix