TO: Technical Advisory Group for the Napa County Groundwater Sustainability Agency
FROM: Brian D. Bordona, Director of Planning, Building and Environmental Services
REPORT BY: Jamison Crosby, Natural Resources Conservation Manager
SUBJECT: Sustainable Conservation - Groundwater Recharge Guide for Vineyards
RECOMMENDATION
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Wendy Rash, Project Director of Water for the Future team at Sustainable Conservation, will provide an overview of their publication, A Groundwater Recharge Guide for Vineyards, prepared by Sustainable Conservation and the California Sustainable Winegrowing Alliance (June 2026), to help winegrape growers evaluate, plan, and implement on-farm groundwater recharge to contribute to regional groundwater sustainability.
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Procedure
Staff introduces.
Questions and answers with the TAG.
Public comments.
BACKGROUND AND DISCUSSION
In June 2026, Sustainable Conservation and the California Sustainable Winegrowing Alliance (CSWA) released A Groundwater Recharge Guide for Vineyards to help winegrape growers evaluate, plan, and implement on-farm groundwater recharge to contribute to regional groundwater sustainability. As California’s wine regions face growing groundwater pumping regulations under the Sustainable Groundwater Management Act (SGMA), the guide equips growers with science-backed methods to plan and implement Flood-Managed Aquifer Recharge (Flood-MAR) or other MAR approaches safely and effectively on their farms.
Vineyards are often strong candidates for on-farm recharge. They typically use less nitrogen fertilizer than many other crops, reducing groundwater contamination risk, and excess surface water for recharge is typically available in winter - when vines are dormant and can tolerate periodic flooding. The guide pairs Sustainable Conservation’s expertise in on-farm recharge with CSWA’s knowledge of sustainable winegrowing practices, making it the first resource of its kind designed specifically for California’s winegrape industry.
Wendy Rash of Sustainable Conservation will present an overview of the guide and also describe best management practices that winegrape growers can implement to increase retention of stormwater occurring naturally on their fields and/or via surplus water that, when determined to be available, may be additionally applied in winter through MAR approaches.
ENVIRONMENTAL IMPACT
ENVIRONMENTAL DETERMINATION: The proposed action is not a project as defined by 14 California Code of Regulations 15378 (State CEQA Guidelines) and therefore CEQA is not applicable.
SUPPORTING DOCUMENTS
A. A Groundwater Recharge Guide for Vineyards (presentation by Wendy Rash of Sustainable Conservation, November 12, 2026).
B. A Groundwater Recharge Guide for Vineyards, Sustainable Conservation and the California Sustainable Winegrowing Alliance, June 2026.