Groundwater levels in the Arroyo Seco subbasin remain near sustainability targets following recent wet years; General Manager Weeks said demand management is not needed right now. A five-year Groundwater Sustainability Plan update is expected to be released for a 90-day public review in early September, with a public hearing planned for mid-January. Coastal seawater intrusion continues to pose a major unresolved challenge.
A demand management framework is being developed using historical recharge trends, though pumping reductions remain decades away unless long-term basin recovery fails. The Groundwater Sustainability Plan update is due January 2027, with public hearings expected this summer. Separately, a brackish water desalination project addressing seawater intrusion carries an estimated $1.4 million price tag, with unresolved technical questions and a board recommendation pending.
Draft Forebay/Arroyo Seco Cone fees are expected to be similar to last year, possibly slightly lower. A speaker warned fee-setting may not follow the 2021 coordination agreement, risking liability for both GSAs. Weeks relayed analysis tying modest long-term declines to reduced recharge, not pumping, and noted thresholds might not be reached until about the 2070s. Staff will bring a proposed fee-engagement process next month.
Arroyo Seco basin remains sustainable with no threshold violations in five years, and a demand management framework tailored to drought-condition triggers is being developed. Concerns were raised over a potential valley-wide fee to fund voluntary demand management, with public warnings it may be unnecessary here and vulnerable to legal challenge. Board members also questioned the use of a 30-year modeling window over the full 100-year data record for assessing long-term groundwater trends.
Board approved a scope of work to develop a demand management framework for the Arroyo Seco area, amid technical findings of weak correlation between pumping and water levels that raise questions about how effective demand management would be locally. Equity concerns were also raised about funding programs aimed mainly at seawater intrusion issues in the northern valley.
