Madera County and its GSAs adopt joint amendment to Madera Subbasin GSP, file periodic evaluation and sign ISW memorandum

Madera County supervisors and the Madera Subbasin Groundwater Sustainability Agencies approved a joint amendment to the Madera Subbasin Groundwater Sustainability Plan (GSP), adopted a five‑year periodic evaluation and authorized an interconnected surface water memorandum of understanding to coordinate data and technical work with neighboring agencies and federal partners.

The action, taken by the Board of Supervisors acting as the Madera County Groundwater Sustainability Agency (MCGSA) on Jan. 28, 2025, approves revisions responding to Department of Water Resources (DWR) corrective actions, updates interim subsidence milestones and clarifies monitoring and water‑quality approaches. The board also authorized submittal of the amendment, the periodic evaluation and a second amendment to the coordination agreement to DWR by the Jan. 31 deadline.

The amendment addresses six corrective actions DWR identified in its 2023 approval letter, including enhanced coordination among GSAs, clearer links between groundwater levels and subsidence, revised interim subsidence milestones that step down to zero by 2040, clarified groundwater‑quality thresholds and a plan to advance domestic‑well mitigation. John Davids of Davids Engineering summarized the technical responses and said the GSAs now use a common groundwater model and have increased coordination among technical teams. “We have been successful with the facilitation support services grant,” Davids said during the presentation.

The periodic evaluation reviewed subbasin performance against the six sustainability indicators. Presenters reported that groundwater levels and storage proxies show most monitoring wells are meeting interim milestones, water‑quality concentrations remain generally below interim thresholds at representative sites and subsidence at representative benchmarks so far remains below the revised five‑year limits. On interconnected surface water, presenters said DWR guidance is pending and the newly proposed memorandum of understanding (MOU) will support shared data, a technical committee and coordinated ISW work plans with the Bureau of Reclamation, Friant Water Authority and neighboring GSAs.

Consultants and county staff summarized project and management action progress: across the seven GSAs in the subbasin, about 43% of the planned average benefit toward sustainability has been realized in the first five years, with uneven progress among GSAs. The consultants said the full suite of projects and management actions modeled in the GSP — if implemented — would shift the subbasin to a net positive recharge over a 50‑year representative hydrology period; the presenters noted that hydrology remains a key variable.

Public commenters included Noah Lopez of the Madera Ag Water Association, who urged recognition of the county’s existing allocation (demand management) program and supported a narrowly tailored GSP fee limited to domestic‑well mitigation. A motion to approve the plan amendment, periodic evaluation, the interconnected surface water MOU and the coordination agreement passed on roll call (supervisors Rogers, Wamha, Poitras and Pro Tem McCauley voting yes).

County staff said the ISW MOU contains no immediate financial obligation for the county; future costs for any joint studies or projects would be subject to separate approvals. Staff also said the amendment includes additional text clarifying the GSAs’ continuing commitment to develop a domestic well mitigation program and that complete responses to public comments are included in the plan appendices.

The county and GSAs will file the plan amendment, the periodic evaluation and the coordination agreement with DWR by the statutory deadline. The MOU and plan amendment will be used to guide quarterly technical coordination meetings and annual coordination workgroup meetings required by the coordination agreement.