Salinity and Temperature in South San Francisco Bay, California, at Dumbarton Bridge: Results from the 1999-2002 Water Years and an Overview of Previous Data

U.S. Geological Survey Water Resources Investigation Report 03–4005

By Laurence E. Schemel, Randall L. Brown and Norton W. Bell


Salinity and temperature were measured in near-surface waters at Dumbarton Bridge in South San Francisco Bay during the 1999–2002 water years (1999WY–2002WY). The complete data set from this site, which included 1990WY–1993WY and 1995WY–1998WY, provided a time–series of observations covering a wide range of hydrologic conditions. These conditions included critically dry years and years with above-normal and near–record precipitation and discharges from the major rivers and local streams. Data collection at 15–minute intervals allowed resolution of variability associated with daily tides and other short-term phenomena. Both local stream discharges to South San Francisco Bay and Sacramento–San Joaquin River discharges to North San Francisco Bay affected salinity at Dumbarton Bridge. Salinity at Dumbarton Bridge varied with the daily tides, and the lowest salinity values (annual) coincided with precipitation and freshwater inflows usually in winter. Short–term and seasonal variations in temperature at Dumbarton Bridge typically followed changes in air temperature and solar irradiance.




Hydrologic Characteristics of the 1990-2002 Water Years

Hydrography, Tides, and Weather



Results and Discussion

Seasonal and Interannual Variability

Variability on Tidal Time Scales

Implications for Wastewater Dilution and Transport


References Cited

Appendix A: Illustrations


This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.


Download the Report (WRIR03-4005.PDF, 0.7 MB)


The text of previous reports are available here in pdf format. All of these PDF files were originally prepared prior to June 21, 2001. Since that time these image only scans have been processed to make them accessible to screen-reading programs.


Download Report for the 1990-1993 Water Years: OFR-95-326 (OFR95-326.PDF, 1.2 MB)


Download Report for the 1995-1998 Water Years: OFR-98-650 (OFR98-650.PDF, 0.4 MB)


Data tables are available here in text (TXT) format.


Download Self Extracting file containing data for 1990 (Dmbwy90.EXE, 0.3 MB)
Download Self Extracting file containing data for 1991 (Dmbwy91.EXE, 0.4 MB)
Download Self Extracting file containing data for 1992 (Dmbwy92.EXE, 0.3 MB)
Download Self Extracting file containing data for 1993 (Dmbwy93.EXE, 0.4 MB)

Download Self Extracting file containing data for 1995-1998 (Dmb9598.EXE, 1.2 MB)
Download Self Extracting file containing data for 1999-2002 (Dmb9902.EXE, 0.9 MB)

Download Self Extracting file containing data for 2003 (Dmb03wy.EXE, 554 KB)

Data Update

Download Self Extracting file containing data for 2004 (Dmb2004.EXE, 513 KB)

Download Self Extracting file containing data for 2005-2006 (dmb0506wy.ZIP, 1.6 MB)


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David H. Peterson,

Chief, Geochemistry of Rivers and Estuaries Project

U.S. Geological Survey, MS 439

345 Middlefield Road

Menlo Park, FCA 94025


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