As of 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) is now in the process of reviewing the GSP. DWR will notify those on its Sustainable Groundwater Management Program email list when the GSP has been reviewed.
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)?
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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?
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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):
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TM 1 – Data Management System Evaluation and Selection (working draft as of 11/2018)
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TM 2 – Data Compilation and Data Gaps Assessment (working draft as of 6/2019)
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TM 3 – Numerical Groundwater Model Evaluations and Recommendations (working draft as of 12/2018; revision 9/2019)
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TM 4 – Not applicable – [does not exist; removed from initial scope of work]
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TM 5 – Stakeholder Communication and Engagement Plan (working draft as of 3/2019)
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TM 6 – Groundwater Conditions and Hydrogeologic Conceptual Model (working draft as of 11/2019)
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TM 7 – Not applicable – [does not exist; removed from initial scope of work]
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TM 8 – Water Budget and Preliminary Estimate of Sustainable Yield (working draft as of 5/2021)
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TM 9 – Summary of Monitoring Network Assessment and Preliminary Monitoring Plan (working draft as of 4/2020)
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TM 10 – Delineation of Management Areas (short paragraph will be included in the Draft GSP as the GSAs decided to not delineate Management Areas)
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TM 11 – Establishment of Sustainability Criteria (working draft as of 3/2021)
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TM 12 – Proposed Projects and Management Actions (working draft as of 4/2021)
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TM 13 – GSP Implementation Plan (working draft as of 6/2021)
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TM 14 – Proposed Monitoring Network and Protocols (based on TM 9, will be updated for Draft GSP)
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