DATE: November 4, 2025
TO: Board of Supervisors
SUBMITTED BY: Steven E. White, Director
Department of Public Works and Planning
SUBJECT: Delta-Mendota Subbasin Domestic Well Mitigation Policy
RECOMMENDED ACTION(S):
TITLE
Approve and adopt the Delta-Mendota Subbasin Domestic Well Mitigation Policy.
REPORT
Approval of the recommended action will adopt the Delta-Mendota Subbasin (Subbasin) Domestic Well Mitigation Policy (Policy). The purpose of the Policy is to mitigate the effects that may be felt by domestic water users whose wells have gone dry or are in imminent threat of going dry within the Subbasin. The policy also addresses mitigation for water quality for domestic well users within the boundaries of their respective Groundwater Sustainability Agency (GSA) pursuant to the Groundwater Sustainability Plan (GSP). This item pertains to locations in District 1.
ALTERNATIVE ACTION(S):
Your Board may determine not to approve the recommended action, however, it would likely result in increased costs and delay the GSP implementation, and any coordination obligation required by the Sustainable Groundwater Management Act (SGMA).
FISCAL IMPACT:
There is no additional Net County Cost associated with the recommended action. Sufficient appropriations for cost of Fresno County Management Areas A & B (FCMAB) activities are included in the CAO’s Org 2540 FY 2025-26 Adopted Budget.
DISCUSSION:
SGMA provides for the establishment of a local GSA to manage groundwater sustainability within groundwater subbasins defined by the California Department of Water Resources (DWR). SGMA was signed into law on September 16, 2014, and is codified at California Water Code sections 10720 through 10738. SGMA established a new structure for managing California’s groundwater resources at a local level by local agencies. Each GSA was required to develop and implement a GSP to ensure a sustainable yield of groundwater, without causing undesirable results. Failure to implement a GSP and meet its sustainability goal could result in the State Water Resources Control Board (SWRCB) asserting its authority to manage local groundwater resources.
In anticipation of potential intervention by SWRCB, the GSAs entered into a Memorandum of Agreement on December 11, 2023, agreeing to collectively adopt a single GSP for the Subbasin instead of submitting multiple plans for each GSA to address the deficiencies identified by DWR with the original submittal of the coordinated GSPs. The County’s portion of the single GSP was approved by the Board on September 10, 2024, and re-submitted for review by the State.
To assure compliance with SGMA within the Subbasin, Department staff participates in regular meetings with representatives from the local participating GSAs. The County serves as the exclusive GSA for two areas designated as FCMAB, approved by the Board on May 2, 2017.
Pursuant to the single Subbasin GSP, Minimum Thresholds (MTs) for groundwater levels across the Subbasin are set at 2015 seasonal low groundwater levels. This means GSAs in the Subbasin are already committed to maintaining groundwater levels above what was measured in 2015. Since implementation of the Subbasin’s original GSPs began in 2020, GSAs in the Subbasin have successfully avoided undesirable results that would occur by water levels falling below 2015 seasonal lows. This Policy is meant to serve as a last line of defense to protect domestic groundwater users in the unlikely event that the Subbasin GSAs’ efforts fail to maintain those groundwater levels above the MTs.
The overall purpose of the Policy is to mitigate the effects that may be felt by domestic water users whose wells have gone dry or are in imminent threat of going dry due to groundwater levels declining within the Subbasin. Subject to specific conditions, this Policy also addresses mitigation for water quality for domestic well users. The recommended Policy will consider impacts to domestic wells, as well as community water systems that supply water for domestic or residential use. Additionally, the Policy allows for individual GSAs within the Subbasin to consider including additional well uses within their jurisdictional boundaries.
As part of Fresno County’s Pumping Reduction Plan, approved by your Board on March 11, 2025, the Subbasin Coordination Committee will regularly review groundwater levels and water quality data reported by the GSAs. This proactive approach aims to maintain and protect groundwater resources.
REFERENCE MATERIAL:
BAI #45, March 11, 2025
BAI # 6, September 10, 2024
BAI # 59, January 29, 2019
BAI # 13, May 2, 2017
BAI # 11, May 2, 2017
BAI # 12, March 7, 2017
ATTACHMENTS INCLUDED AND/OR ON FILE:
On file with Clerk - Delta-Mendota Subbasin Domestic Well Mitigation Policy
CAO ANALYST:
Maria Valencia