GM: Hydrogeologic model shows deep‑aquifer uncertainty; seawater intrusion will require major projects and time
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Summary
Arroyo Seco GSA General Manager Curtis Weeks briefed the board on a hydrogeologic model update that found limited knowledge about a deep aquifer in the northern basin, uncertainty about recharge mechanisms, and ongoing seawater intrusion on the East Side that may require multi‑decade projects and substantial funding.
Curtis Weeks, the Arroyo Seco GSA general manager, delivered an oral status report summarizing recent advisory‑committee and implementation‑subcommittee work and an updated hydrogeologic model for the Salinas Valley basins.
Weeks said the model highlights uncertainty in a deeper northern aquifer where only two wells were identified; recharge pathways for that deep body of water are unclear because clay layers (aquitards) block direct surface recharge. He cautioned that limited data make it difficult to assess how the deep aquifer connects to shallower systems and said more monitoring and study are needed.
The general manager also warned about seawater intrusion on the East Side and a pronounced low in groundwater elevations east and south of Salinas. "Raising groundwater elevations to the pressure 180 will have an impact, but it will not have enough of an impact to push back seawater intrusion in the timeframe that we've got," Weeks told the board, noting that groundwater mixing and slow subsurface movement mean solutions may take decades.
Weeks characterized the water‑supply projects under consideration as large and long‑term: planning, CEQA and funding can take a decade, and project costs are likely in the "hundreds of millions" of dollars. He said the board needs to consider taking action this year to advance projects because sustainability goals stretch to 2040.
Public commenters reiterated concerns about who pays and which jurisdictions benefit. John, a commenter representing city interests, reminded the board that cities have contributed to Salinas Valley projects for decades and suggested cities could be partners in northern projects, including aquifer storage and recovery and regional recycled‑water efforts.
The report was informational; no formal action was taken on projects at this meeting. Staff will continue advisory‑committee work, expand monitoring where needed, and bring project proposals and funding options back to the board for consideration.
