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Santa Clara Valley – San Mateo Plain

Statistics

At-A-Glance

Located in California’s San Francisco Bay hydrologic region, the Santa Clara Valley – San Mateo Plain subbasin is 48,100 acres in size. This Very Low priority basin is home to an estimated 292,819 people (2010 value). It has approximately 348 wells, of which approximately 10 are water supply wells. Groundwater accounts for approximately 10 percent of the basin’s water supply.

Source: CA DWR
Source: CA DWR

Basin Notes

2003: Bulletin 118 basin description

2017: San Mateo Plain Groundwater Subbasin: A Local Case Study, Stanford University

2018: Basin prioritization comments –

  • Declining groundwater levels: 1) CASGEM/WDL/GWIDS: No data or data insufficent to determine GWL status. Source: DWR 2) One hydrograph in Groundwater Reliability Partnership for the San Mateo Plain Sub-basin presentation, Slide 12, showed groundwater levels increasing 1962 to 2015. Source: GRP_Presentation_10_19_15_FINAL.pdf
  • Salt intrusion: 1) According to the Regional Water Quality Control Board (RWQCB), saltwater intrusion has occurred to groundwater within the San Mateo Plain sub-basin. The DWR found that groundwater quality in the sub-basin contains high concentrations of sodium; samples from wells in the area also found concentrations of nitrates/nitrogen in excess of maximum contaminant levels established by the California Department of Health Services and the United States Environmental Protection Agency.

San Mateo Plain subbasin given draft medium priority, subjecting it to SGMA

Final Basin Prioritization: Very Low.

GSA Information

Not Subject to SGMA No items found

Models