In August 2014, the California Legislature passed, and in September 2014 the Governor signed, legislation creating the Sustainable Groundwater Management Act (“SGMA”) “to provide local groundwater sustainability agencies with the authority and technical and financial assistance necessary to sustainably manage groundwater” (Wat. Code, § 10720, (d)). SGMA requires sustainable management through the development of groundwater sustainability plans (“GSP”), which can be a single plan developed by one or more groundwater sustainability agencies (“GSAs”) or multiple coordinated plans within a basin or subbasin (Wat. Code, § 10727). SGMA requires a GSP to be developed and implemented to manage groundwater in all basins designated by the Department of Water Resources (“DWR”) as medium or high priority, including the Delta-Mendota Subbasin (basin number 5-22.07).

As an exclusive GSA for a portion of the Delta-Mendota Subbasin, the GSA has the authority to draft, adopt, amend, and implement a GSP (Wat. Code, § 10725 et seq.; § 10728.4). The GSA was originally a member of the San Joaquin River Exchange Contractors GSA Group formed for the purpose of developing a GSP and coordinating sustainable groundwater management in the Delta-Mendota Subbasin (Wat. Code, § 10723.6(i)). The other GSAs in the Delta-Mendota Subbasin initially prepared separate GSPs for other regions of the Delta-Mendota Subbasin for a total of six GSPs covering the entire Delta-Mendota Subbasin (each, a “GSP Group”). The GSAs from all six GSP Groups entered into a Coordination Agreement effective December 12, 2018 (the “Coordination Agreement”), to comply with SGMA and ensure that the multiple GSPs within the Delta-Mendota Subbasin would be developed and implemented utilizing the same methodologies and assumptions, that the elements of the GSPs are appropriately coordinated to support sustainable management, and to show how the multiple GSPs will achieve the sustainability goal for the Subbasin.  The Coordination Agreement also established a Coordination Committee composed of representatives from each GSP Group, outlined information sharing obligations, procedures for resolving conflicts, and designated the Authority as the Plan Manager for the Delta-Mendota Subbasin. On January 6, 2020, the Subbasin Plan Manager submitted the Coordination Agreement and the six GSPs.

On January 21, 2022, DWR completed its review of all the GSPs in the Delta-Mendota Subbasin and released a letter determining that the GSPs for the Delta-Mendota Subbasin as a whole were “Incomplete” and identified deficiencies and corrective actions for the GSAs in the Delta-Mendota Subbasin to take. Amended or modified GSPs addressing the corrective actions from each GSP Group had to be submitted to DWR by July 20, 2022. However, in its March 2, 2023 Determination Letter, DWR deemed the Revised 2022 GSP “Inadequate.” The main concern of DWR was that the six GSPs were not truly coordinated and using the same data and methodologies.

Under SGMA, if DWR deems a GSP or GSPs inadequate, this triggers the State Water Resources Control Board (“SWRCB”) intervention process. (Wat. Code, § 10735 et seq.).  As such, in response to DWR’s “Inadequate” determination and prior to the Basin’s probationary hearing (which is currently scheduled for some time in the spring 2025), the GSAs in the Delta-Mendota Subbasin signed and executed a Memorandum of Agreement (the “MOA”) on December 11, 2023, superseding the 2018 Coordination Agreement. Through the MOA, the Parties agreed to mutually cooperate to adopt a single GSP (the “2024 GSP”) for the Subbasin, and to implement the GSP within their respective GSA territories. The 2024 GSP synthesizes, updates, and replaces content from the Revised 2022 GSPs and Common Chapter to address the Corrective Actions outlined by DWR in its March 2023 “Inadequate” Determination Letter. The MOA becomes effective upon the adoption of the 2024 GSP.  The MOA establishes a Coordination Committee to provide a forum for the GSA Groups to work collaboratively and develop recommendations for technical and substantive subbasin-wide activities.

In response to the Inadequate Determination Letter, the Delta-Mendota Subbasin GSAs, through the Coordination Committee, hired EKI to help prepare one GSP.  The Subbasin GSAs have revised the Sustainable Management Criteria (SMCs) and Undesirable Results (URs) definitions to be the same throughout the Subbasin and agreed to set water level minimum thresholds at 2015 water levels.  Among other items in the GSP, the monitoring network, modeling and coordination efforts were updated to be consistent amongst the GSAs. Representatives of the Subbasin GSAs met with DWR and SWRCB staff on several occasions to get clarification on what was needed to have an approved GSP.  Several GSAs also participated in hosting tours for SWRCB Board members and staff so that they could see the “boots on the ground” issues in the Subbasin.  Additionally, the Subbasin adopted a Domestic Well Mitigation Policy and Application that will be adopted as part of the 2024 GSP.

The 2024 GSP was jointly prepared by all 23 GSAs and the following seven GSA Groups, which are comprised of all 23 GSAs: the Aliso Water District GSA Group; the Farmers Water District GSA Group; the Fresno County Management Areas A and B (FCMA) GSA Group; the Grassland GSA Group; the Northern Delta-Mendota GSA Group; the Central Delta-Mendota GSA Group; and the San Joaquin River Exchange Contractors (SJREC) GSA Group. In June 2024, the Coordination Committee posted a draft of the 2024 GSP on the Subbasin’s website for public comment and held public workshops regarding the revisions to the GSP.  After considering public comments and upon further discussion, on July 22, 2024, the Coordination Committee unanimously recommended that all GSAs in the Delta-Mendota Subbasin adopt the 2024 GSP.

The GSA’s are now holding public hearings to consider adoption of a resolution to adopt the 2024 GSP for the Delta-Mendota Subbasin for submittal to the SWRCB.

Links

Delta-Mendota Subbasin Groundwater Sustainability Webinar Briefing – Tuesday, August 27, 2024
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(599kb)

Groundwater Sustainability Plan for the Delta-Mendota Subbasin – July 2024
https://deltamendota.org/final-gsp-documents/

First Amended Groundwater Sustainability Plan for the San Joaquin River Exchange Contractors GSP Group in the Delta-Mendota Subbasin (5-022.07) (Edited Version)
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(316mb)

First Amended Groundwater Sustainability Plan for the San Joaquin River Exchange Contractors GSP Group in the Delta-Mendota Subbasin (5-022.07) (Clean Version)
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(315mb)

Groundwater Sustainability Plan for the San Joaquin River Exchange Contractors GSP Group in the Delta-Mendota Subbasin (5-022.07)
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(117mb)

Groundwater Sustainability Plans
https://www.water.ca.gov/Programs/Groundwater-Management/SGMA-Groundwater-Management/Groundwater-Sustainability-Plans

Best Management Practices and Guidance Documents
https://www.water.ca.gov/Programs/Groundwater-Management/SGMA-Groundwater-Management/Best-Management-Practices-and-Guidance-Documents

Data and Tools
https://www.water.ca.gov/Programs/Groundwater-Management/Data-and-Tools