Sustainable Groundwater Management

Alternative Groundwater Sustainability Plan (GSP)

Basin Analysis Report for the Napa Valley Groundwater Subbasin

Final documents of the Napa Valley Groundwater Sustainability - Basin Analysis Report for the Napa Valley Subbasin (Alternative GSP) are available below. 

The Final Alternative GSP was submitted to the CA Department of Water Resources (DWR) on December 16, 2016. Napa County is currently awaiting DWR review. A hard-copy of the Alternative GSP is available at the Napa County Flood Control and Water Conservation District Office, 804 First St., Napa, (707) 259-8600.

The 2014 Sustainable Groundwater Management Act (SGMA) provides a framework for sustainable management of groundwater resources by local authorities. The act establishes a timeline - 20 years - to implement actions that achieve long-term groundwater sustainability. It protects existing surface water and groundwater rights and does not impact drought response measures. DWR is in charge of the SGMA Program and has developed guidelines for local agencies to follow. Napa County is currently meeting the requirements of the SGMA.

Napa County and its groundwater consultant completed work to meet the requirements of SGMA, which was in the form of an Alternative Groundwater Sustainability Plan/Basin Analysis Report, an approved Alternative to a Groundwater Sustainability Plan (GSP). The report, Napa Valley Groundwater Sustainability - Basin Analysis Report for the Napa Valley Subbasin (linked below), provides an extensive analysis of the Napa Valley groundwater Subbasin and demonstrates it has operated within its sustainable yield and that it is being managed consistent with the goals of SGMA and DWR regulations.

For medium and high priority groundwater basins/subbasins, a Basin Analysis Report or other Alternative GSP must be submitted to DWR by January 1, 2017. The Napa Valley Subbasin (map) is the only basin in Napa County with a priority ranking by DWR that is subject to SGMA at this time.

DWR is currently in the process of evaluating and re-prioritizing all of the groundwater basins across California. DWR’s basin re-prioritization effort is recommending modifying the Napa Valley Subbasin from a medium to a high priority ranking and the Napa-Sonoma Lowlands Subbasin from a very low to medium priority ranking based upon the relative importance of groundwater within each of the basins. DWR is also reviewing a basin boundary modification for the Lowlands Subbasin that was submitted by the Sonoma Valley Groundwater Sustainability Agency. DWR’s reprioritization is still in draft and will not be final until late 2018 or early 2019. Please see DWR’s basin re-prioritization website for details and updates on their process.

An Alternative GSP/Basin Analysis Report for the Napa Valley Subbasin was presented to the Board of Supervisors at a Special Meeting on December 13, 2016. At that meeting, the Board approved the report and its submittal to DWR. The Report was submitted to DWR on December 16, 2016. DWR is currently reviewing the Alternative GSP/Basin Analysis Report. Their comments and recommendations are expected by early 2019. Please see DWR's SGMA Portal for Alternatives and Reporting for additional information and updates. A hard-copy of the report is available for review at the Napa County Flood Control and Water Conservation District office, 804 First St., Napa, (707) 259-8600. An electronic copy of the report is available via the links below.

SGMA requires annual reporting on groundwater conditions and on any actions taken by Napa County to ensure the sustainable management of Napa Valley groundwater resources. The 2017 Annual Report is available on the WICC's groundwater monitoring page. It describes groundwater conditions in the Napa Valley Subbasin and provides an update on the County’s SGMA implementation efforts through water year 2017, as required by SGMA and DWR. In addition, the 2017 Annual Report includes an Amendment to the 2016 Alternative GSP/Basin Analysis Report, establishing a Northeast Napa Management Area. The Amendment complements the management actions in the 2016 Alternative GSP/Basin Analysis Report for the Napa Valley Subbasin and enables continued attainment of the SGMA Sustainability Goals for the Napa Valley Subbasin.

Annual reports developed for SGMA purposes are required to be submitted by April 1 of each year following adoption of a GSP or Alternative GSP (Regulations Section 356.2). Napa County submitted the 2017 Annual Report to DWR on March 23, 2018 after public notice and presentation at a public meeting of the Board of Supervisors on March 20, 2018.

Bain Analysis Report Documents  

Final Documents Submitted to DWR:

Final Basin Analysis Report
Final Basin Analysis Report Appendices 1 of 2
Final Basin Analysis Report Appendices 2 of 2
Final Basin Analysis Report Alternative Elements Guide
Final Basin Analysis Report Supervisor Approval and Authorization
Final Basin Analysis Report CEQA NOE
Final Basin Analysis Report MWELO Implementation
Final Basin Analysis Report Well Construction Standards
Final Basin Analysis Report Groundwater Conditions and Monitoring Report 2011

Additional local SGMA documents and related information can be found here on the WICC and on Napa County's groundwater webpage.

Current groundwater studies, reports, links, guides and other related items are available in the WICC's groundwater information library.

Napa County Groundwater Program Contact

Patrick Lowe, Natural Resources Conservation Manager, (707) 259-5937,