Chowchilla GSP revisions and MOUs on domestic wells, demand management and subsidence forwarded to county board

The Madera County Groundwater Sustainability Agency (GSA) committee voted 2-0 on March 4, 2025, to forward a package of 2025 revisions to the Chowchilla Subbasin Groundwater Sustainability Plan (GSP) and three related memoranda of understanding (MOUs) to the Board of Supervisors for adoption.

The package includes amendments to the Chowchilla management-zone MOU, a demand-management MOU, and an amendment to the domestic well mitigation MOU. Committee staff said the revisions respond to deficiencies cited by the State Water Resources Control Board after the plan was found inadequate and placed under state board jurisdiction.

Committee staff noted the revisions change several program rules. On domestic well mitigation, the draft now clarifies funding sources (the four subbasin GSAs, with voluntary grower contributions in one instance) and establishes a $30,000 cap per domestic-well mitigation case. “They didn’t want a funding cap. We’ve capped it at $30,000,” said Stephanie, GSA staff, during the presentation. Staff also said the program will include water-quality testing through a partnership with the Chowchilla Nitrate Management Zone and temporary mitigation measures intended to provide water within 24 hours when a well is reported dry.

On the question of which wells are eligible, staff said the State requires domestic-well mitigation to be available regardless of when a well was drilled, subject to an investigation to confirm the dry well resulted from groundwater decline rather than pump failure or other causes. “The state wants a domestic well mitigation to fund domestic wells regardless of when the well was drilled,” Stephanie said. That position means wells drilled before 2014 may be eligible if the investigation shows a recent decline caused the loss of supply.

The revisions also tighten language around undesirable results and sustainable management criteria. The GSP draft replaces a previously ambiguous formulation with a clearer threshold that staff summarized as: if more than 25 percent of representative monitoring-site wells fall below minimum thresholds for two consecutive fall measurements, an undesirable result would be declared. The committee heard that the state had asked for clearer milestones and earlier interim targets, and staff said those changes are reflected in the draft and will be revisited as part of later amendments.

The demand-management MOU requires additional subbasin parties to develop a demand-management program that would be triggered if certain conditions occur. Staff described one numeric trigger in the draft: if more than 75 domestic wells go dry in the Chowchilla Subbasin during the implementation period, additional actions — including demand management measures by participating parties — would be required.

Land subsidence was also addressed. Staff said monitoring in the eastern management area will be increased and that the revised plan reduces allowable exceedance language and adds interim milestones to limit subsidence more rapidly. Those rules and triggers are being codified in a subsidence and demand-management MOU, staff said.

Public commenters at the committee meeting urged coordination across GSAs and use of the Chowchilla domestic-well program as a model. Grower Mark Peters urged replication of the Chowchilla approach in Madera: “Why reinvent the wheel?” he said. Grower Howard Jake raised a separate concern about eligibility and oversight for wells drilled before 2014, asking the committee to consider how the program treats older wells.

The committee motion to forward the GSP revisions and the three MOUs to the Board of Supervisors passed with a 2-0 roll-call vote. The revisions are scheduled for a publicly noticed hearing next week before the Board of Supervisors and then submission to the State Water Resources Control Board and the Department of Water Resources for final review where required.

If adopted by the Board of Supervisors and the other subbasin GSAs, staff said the revised GSP will be resubmitted to DWR and the State Water Resources Control Board with the aim of returning the Chowchilla Subbasin to DWR jurisdiction and away from the state board’s oversight.

Committee members and staff said the changes are part of an adjustable, multi-year process with five-year reviews planned under state law.