Historical bathymetry and bathymetric change within San Francisco Bay, California: 1855 to 2005

Here we present a time series of San Francisco Bay bathymetric grids created from historical hydrographic surveys collected by the National Ocean Service (NOS) and its predecessor, the United States Coast and Geodetic Survey, from the 1850s to 1980s and one additional survey of south San Francisco Bay collected in 2005 by Sea Surveyor, Inc. Using surface modeling software, the soundings from each survey were supplemented with hand-drawn contours and shorelines obtained from topographic sheets to generate bathymetric DEMs at a horizontal resolution of 25 or 50 meters. The DEMs are divided into four subembayments: Central, South, San Pablo, and Suisun Bays and each subembayment was surveyed either five or six times over the approximately 150-year timespan. The bathymetric DEMs are provided in GeoTIFF format, vertically referenced to the Mean Lower Low Water (MLLW) tidal epoch referenced at the time of data collection. The consecutive surveys, generally collected 20-30 years apart, were then adjusted to account for changes in sea level over the intervening time periods and differenced to reveal amounts of sediment deposition and erosion.