Skip to content

Groundwater Sustainability Plan

In 2024, the 23 Groundwater Sustainability Agencies (GSAs) of the Delta-Mendota Subbasin adopted a new, single Groundwater Sustainability Plan (GSP). The new single GSP will serve as a roadmap for the GSAs to achieve groundwater sustainability in compliance with SGMA. On April 7, 2025, the State Water Resources Control Board unanimously adopted a resolution to return the Delta-Mendota Subbasin to the jurisdiction of the California Department of Water Resources.
Click Here

GSP Chapters

Executive Summary

Table of Contents

Introduction

Plan Area

Basin Setting

Groundwater Conditions

Water Budget Information

Sustainable Management Criteria

Monitoring Network

Projects and Management Actions

Plan Implementation

References and Technical Studies

Appendices

Joint Powers Authority

The 23 Delta-Mendota Subbasin GSAs have formed a Joint Powers Authority (JPA) to collaboratively manage groundwater through a single GSP. 

A JPA is a legal entity formed by two or more public agencies to jointly exercise common powers. JPAs allow agencies to cooperate, pool resources for insurance, issue bonds, and/or manage regional projects including the implementation of a GSP. 

Since the formation of GSAs in the Subbasin, the San Luis & Delta-Mendota Water Authority (SLDMWA) has provided fiscal, contracting and administrative services for the subbasin. The assistance of SLDMWA was invaluable and greatly appreciated by the GSAs. Recently, SLDMWA’s Board consolidated its mission to focus on core objectives and transitioned away from providing these services. In response, the Subbasin GSAs evaluated several options to ensure continuity of necessary services and decided to form a JPA. 

The new Delta-Mendota Subbasin GSAs Joint Powers Authority, governed by a 7-member board representing all the subbasin GSAs, ensures local control and protects member rights while managing sustainability efforts. The goal of the JPA is to deliver collaborative, efficiency-driven sustainable management of the Subbasin’s groundwater. (Note: Going forward there will be 21 GSAs as Oro Loma and Widren Water Districts have joined the Central DeltaMendota GSA JPA.)

SGMA Data Viewer

As part of DWR's technical assistance to Groundwater Sustainability Agencies (GSAs), other water managers, and the public, DWR has developed the SGMA Data Viewer. The SGMA Data Viewer provides access to groundwater related datasets that are organized by the requirements of SGMA and the Groundwater Sustainability Plan (GSP) regulations for the purpose of supporting GSP development and implementation.
Visit Tool