Since January 19, 2022, the Cosumnes Subbasin Groundwater Sustainability Plan (GSP) has been adopted by the Cosumnes Subbasin Working Group (the predecessor to the Cosumnes Groundwater Authority) and the 7 Cosumnes Subbasin Groundwater Sustainability Agencies (GSAs) (the member agencies of the Cosumnes Groundwater Authority). The California Department of Water Resources (DWR) announced in October of 2023 that they had reviewed and approved the Cosumnes GSP! DWR sent a Determination Letter which includes 6 corrective actions that will help guide our work leading up to the 5-year update.

Cosumnes GSP Annual Report

SGMA requires GSAs to submit annual reports to DWR each April 1 following adoption of a GSP. Annual reports will provide information on groundwater conditions and implementation of the GSP for the prior water year.

Cosumnes GSP Background Information

What is contained in a Groundwater Sustainability Plan (GSP)?

  • A GSP must assess groundwater quantity and determine if there is a balance between water coming in and water leaving the subbasin. If it is determined that groundwater supplies are being depleted over time, the Plan must contain a strategy to reverse this trend and ensure long-term sustainability of the water available to businesses, residences, farms, ranches and ecosystems.

    The GSP must also assess groundwater quality, surface water depletion, land subsidence and other sustainability indicators and propose measures to correct any “undesirable results.” 

What components are in the GSP, and how is the GSP organized?

  • The detailed and technical information in the GSP will be largely based on Technical Memorandums (TMs) that the technical consultant, EKI Environment & Water, Inc., has been developing in coordination with GSAs, stakeholders, and other experts. Whenever an initial draft TM was completed, the draft was provided to the GSAs and stakeholders for review and comment. Feedback has been collected and will be incorporated into the GSP. 

    List of Technical Memos (TMs):