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Western Coastal and Marine Geology
U.S. Geological Survey
Open-File Report 2006-1287
Version 1.0

Sediment Deposition and Erosion in South San Francisco Bay, California from 1956 to 2005

By Bruce Jaffe and Amy Foxgrover


Preliminary maps of bathymetry, intertidal flat, tidal marsh and deposition and erosion in South San Francisco Bay from 1956 to 2005


Sediment deposition and erosion in South San Francisco Bay from 1956 to 2005 was studied by comparing bathymetric surveys made in 1956, 1983, and 2005. From 1956 to 1983, the region was erosional. In contrast, from 1983 to 2005, the region was depositional. Analysis of subregions defined by depth, morphology and location revealed similarities in behavior during both the erosional and depositional periods. During the entire period of the study, there was net erosion in the shallows (<1 m depth) on the eastern shore of the bay north of the Dumbarton Bridge and net deposition in the region south of Dumbarton Bridge. The rates, however, reflected the sediment regime of each time period. Erosional areas were less erosional during the period with net deposition and depositional zones were more depositional. The cause for the increase in deposition from 1983 to 2005 is unknown, but could be related to an increase in sediment supply from Central Bay. The patterns of deposition and erosion and the change in rates are consistent with an increase in sediment supply from the north, as would occur if the supply from Central Bay increased from 1956-1983 to 1983-2005. Additional research is needed to fully understand why South San Francisco Bay became depositional from 1983 to 2005 and to determine the implications of this change to the planned salt pond restoration in the region.

Download Open-File Report 2006-1287 as a 24-page PDF file (7.2 MB)

Also of interest:

USGS Open-File Report 2006-1262, A History of Intertidal Flat Area in South San Francisco Bay, California; 1858 to 2005, By Bruce Jaffe and Amy Foxgrover

USGS Open-File Report 2004-1192, Deposition, Erosion, and Bathymetric Change in South San Francisco Bay: 1858-1983, By Amy C. Foxgrover, Shawn A. Higgins, Melissa K. Ingraca, Bruce E. Jaffe, and Richard E. Smith

For questions about the content of this report, contact Bruce Jaffe

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Maintained by: Michael Diggles
Created: September 22, 2006
Last modified: October 16, 2006 (mfd)