Get Full Government Meeting Transcripts, Videos, & Alerts Forever!
Get email alerts on the Water topic
No spam. Unsubscribe anytime.
Councilmember Hardy summarizes groundwater modeling, says 10% pumping reduction would meet plan goals in many scenarios
Summary
Councilmember Hardy reviewed GSA and state supply-and-demand materials, reporting baseline pumping averages, drought-period increases, and model runs showing a 10% reduction—if achieved countywide and in 1,500-foot stream buffers—reduces threshold exceedances in model scenarios.
Councilmember Hardy provided a technical briefing on the Napa Valley Groundwater Sustainability Agency process and the State Water Resources Control Board's supply-and-demand assessment content. Hardy said the GSA consultants analyzed recharge options and new modelling features that evaluate reductions in pumping in zones near significant streams.
Hardy cited model numbers: a 2005'2014 base-period average pumping of about 15,000 acre-feet per year and a more recent-period (2015'2024) average of about 17,700 acre-feet per year. He said the plan's sustainability goal line calls for a 10% reduction from the base period, roughly to 13,500 acre-feet per year. In model runs, Hardy said a 10% reduction applied within 500 feet of significant streams reduced the number of threshold-exceedance years; applying a 10% cut within 1,500 feet of those streams produced results that met the plan goal in every modeled year.
Hardy cautioned that geography and land costs limit opportunities for large recharge projects in the basin and said success will likely depend on many small projects and demand-reduction measures. He also stressed the role of municipal water systems during drought, noting that while total city demand has fallen under conservation, the city's wells can see higher reliance in emergency conditions and that meeting plan goals will interact with system maintenance and operational needs.
Hardy outlined the regulatory timeline: the Sustainable Groundwater Management Act has a 20-year horizon with five-year progress reports; he said the first progress report from Napa County is due next year and that tougher implementation discussions likely will occur over the next several years as environmental-flow analyses are completed.
