USGS Measurements of Water Quality in San Francisco Bay (CA), 1969-2015 (ver. 4.0 March 2023)

The U.S. Geological Survey maintains a program of water-quality studies in San Francisco Bay (CA) that began in 1969. This Data Release archives and makes available all measurements made from 1969 through 2015. Water-quality constituents include salinity, temperature, light extinction coefficient, chlorophyll-a, dissolved oxygen, suspended particulate matter, nitrate, nitrite, ammonium, silicate and phosphate. Time, Julian date, and three constituents were added retroactively in 2023 to all years: ratio of chlorophyll-a and pheopigments, oxygen percent saturation, and density as Sigma-t. Water samples were collected along a 145-km transect from lower South San Francisco Bay to the lower Sacramento River. Samples were collected at 59 fixed sampling locations, of these 37 became standard long-term sampling stations. All stations are listed in the station location table (SFBstationlocations_19692015.csv) and standard stations are shown on the map (sfbaymap.jpg)