2003: Bulletin 118 basin description

2014: CASGEM basin prioritization – high

2016: Boundary modification approved a boundary change with Madera subbasin 5-022.06

Revised basin boundary description

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