San Joaquin Valley – Delta-Mendota
- Basin Name
- San Joaquin Valley – Delta-Mendota
- Basin Number
- SGMA Basin Priority
- Critically Overdrafted
- Hydrologic Region Name
- San Joaquin River
- Fresno, Madera, Merced, Stanislaus
Located in California’s San Joaquin River hydrologic region, the San Joaquin Valley – Delta-Mendota is 764,964.86 acres in size. This High priority basin is home to an estimated 117,012 people (2010 value), which have been at a rate of 58.
San Joaquin Valley – Delta-Mendota is a(n) basin with approximately 4206 wells, of which approximately 112 are water supply wells. Groundwater accounts for approximately 53 percent of the basin’s water supply.
2014: CASGEM basin prioritization – high
2018: Draft basin priority – high. Groundwater level and subsidence comments:
- CRITICAL OVERDRAFT. Source: DWR 1) CASGEM/WDL/GWIDS: Longterm hydrographs show groundwater level decline. Source: DWR 2) The change in groundwater levels in the northern part of the subbasin (Tracy to Westley) appears to show a consistent decline in groundwater levels. This decline could be indicative of a developing overdraft condition in that area. The change in groundwater levels in the southern part of the subbasin (West of Newman) also appears to show a consistent decline in groundwater levels. This decline could also be indicative of a developing overdraft condition in that area. Source: Groundwater Management Plan for the Northern Agencies in the Delta-Mendota Canal Service Area, Groundwater Management Plan Update, San Luis & Delta-Mendota Water Authority, July 2011
- Sources : 1) Current Land Subsidence in the San Joaquin Valley, USGS; 2) 2014 – Land Subsidence from Groundwater Use in California, California Water Foundation / James W. Borchers / Michael Carpenter, Luhdorff & Salmanini, April 2014; 3) Progress Report: Subsidence in the Central Valley, California, Jet Propulsion Laboratory, California Institute of Technology, NASA 2015-16
2019: Basin boundary modification. Per DWR: It “revised a portion of the shared boundary between the Chowchilla and Delta-Mendota subbasins to align with the jurisdictional boundaries of Triangle T Water District and Clayton Water District.” Phase 2 draft priority: high.
January 2020: Multiple GSPs submitted to the Department of Water Resources.
- San Luis & Delta Water Authority
- Farmers Water District
- Aliso Water District
- Grassland GSA/Merced County
- San Joaquin River Exchange Contractors GSP Group
- Fresno County Management Areas A and B