Why is the Napa Valley Subbasin subject to Sustainable Groundwater Management Act?

Napa Valley Subbasin is categorized by DWR as one of 46 high priority groundwater basins statewide. Medium and high priority basins are subject to the Sustainable Groundwater Management Act (SGMA) requirements. The Department of Water Resources (DWR) prioritized all basins in the state according to the following criteria:

  1. Population size
  2. Anticipated population growth rate
  3. Number of public supply wells
  4. Total number of wells
  5. Irrigated acreage
  6. The degree to which people rely on groundwater as their primary source of water.
  7. Any documented groundwater issues, such as overdraft, subsidence, saline intrusion, and other water quality degradation.
  8. Any other information determined to be relevant by DWR, including threats to local habitat and streamflows.

The Napa Valley Subbasin is categorized as high priority primarily due to the amount of irrigated lands, the density of wells, projected population growth, and the degree to which people rely on groundwater in the Subbasin.

DWR’s basin prioritization process is not a determination of whether groundwater basins are being managed sustainably. Rather, it is a way for DWR to determine the reliance on groundwater in individual basins across California and whether those basins should be subject to the requirements of SGMA.

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1. What is Sustainable Groundwater Management?
2. What are undesirable results in the context of SGMA?
3. What Groundwater Basins are located in Napa County?
4. Why is the Napa Valley Subbasin subject to Sustainable Groundwater Management Act?
5. Return to the Groundwater FAQ page