Water chemistry data for samples collected at groundwater and surface-water sites in the San Ardo Oil Field study area, March 2019–May 2021, Monterey County, California

The California State Water Resources Control Board (State Water Board) initiated the Oil and Gas Regional Monitoring Program (RMP) to assess effects of oil and gas development on groundwater designated for any beneficial use. The U.S. Geological Survey (USGS) is the technical lead in conducting the RMP through the California Oil, Gas, and Groundwater (COGG) Program, working in cooperation with the State Water Board, and in partnership with other State and local agencies. The USGS collected and analyzed groundwater (GW) and surface water (SW) for the San Ardo Oil Field study area, the area within the San Ardo Oil Field administrative boundary and the surrounding five-kilometer buffer zone, in Monterey County, California. Eighteen groundwater, [...]