Calaveras County weighs forming its own groundwater agency to manage SGMA compliance

Calaveras County supervisors on Oct. 28 heard a presentation from the Calaveras County Water District on the Sustainable Groundwater Management Act (SGMA) and a proposal to form a separate Calaveras County Groundwater Sustainability Agency (GSA) for the county’s portion of the Eastern San Joaquin groundwater basin.

Andrew Wrenshaw, water resources manager for the Calaveras County Water District, said the county currently participates in the Eastside San Joaquin GSA under a 2017 memorandum of understanding with Stanislaus County, Stanislaus‑area districts and Rock Creek Water District. Wrenshaw told the board the Eastside basin is designated critically overdrafted, the state requires sustainability by 2040, and multi‑county governance has produced coordination and cost‑sharing challenges. "A Calaveras GSA could provide more efficient governance, reduce overhead and create a more direct communication pathway for foothill communities," Wrenshaw said.

Wrenshaw described several practical differences between the Stanislaus and Calaveras portions of the basin: Calaveras’ share of acreage in the mapped GSA is roughly 40 percent, but irrigated agriculture comprises far less of the county’s area (he estimated about 7 percent of irrigated acreage occurs in the Calaveras portion versus 93 percent in Stanislaus). The county currently pays an estimated 25 percent of an Eastside Groundwater Authority fee administered outside the GSA; detailed allocation depends on projected pumping and will be refined by a contracted groundwater assessment.

Supervisors generally supported staff continuing work with CCWD and returning with options. Supervisor comments focused on coordination and data needs: they asked for a contemporary assessment of how much water is being pumped inside the Calaveras portion, the locations and types of wells, likely mitigation obligations if governance changes, and the financial impact on county operations and budgets. Wrenshaw said the district has contracted Woodard & Curran to update the county’s groundwater assessment and that the county is already coordinating at staff level with Stanislaus County and the Eastern San Joaquin Groundwater Authority.

No formal vote to separate from the Eastside GSA was taken. The board directed staff to continue coordination with CCWD, Stanislaus County and the Department of Water Resources and to return with the updated assessment, cost estimates and governance options for the board’s consideration.

What’s next: staff said they will provide a data‑driven set of options and discuss the proposal with the Eastern San Joaquin Groundwater Authority and DWR. Any change in GSA membership or formal filings would require ministerial actions, MOU revisions, and public outreach.