DWR Releases Draft Prioritization of Groundwater Basins Under SGMA


Groundwater well measure

Agricultural well in Colusa County, where water depth recording takes place to monitor groundwater levels. DWR/2016

SACRAMENTO – The California Department of Water Resources (DWR) today released a draft prioritization of groundwater basins as required by the Sustainable Groundwater Management Act (SGMA). The 2018 SGMA Basin Prioritization is scheduled to be finalized by fall 2018 after a public comment period that starts today and runs through July 18.

SGMA requires local agencies throughout the state to sustainably manage groundwater basins. Under the act, DWR is required to prioritize groundwater basins and direct high- and medium-priority basins to meet a timeline of targets on the path to sustainability. The 2018 SGMA Basin Prioritization released today is a reassessment of the 2016 update of Bulletin 118 Basin Boundaries.

“Sustainably managing groundwater is a critical component of California’s efforts to build a more resilient and reliable water system,” said DWR Director Karla Nemeth. “The Department of Water Resources is committed to working with Groundwater Sustainability Agencies throughout the state to bring basins into sustainability. This prioritization is crucial to that work. We must plan ahead so this vital resource is available for Californians today and in years to come.”

Basin prioritization is the process of classifying basins and subbasins based on a variety of factors identified in the law such as population and number of water wells in a basin. Basins throughout the state are ranked from very-low to high-priority. Basins ranking high- or medium-priority are subject to SGMA.

Of the 517 groundwater basins statewide, the newly released prioritization identifies 109 basins as high- and medium-priority. These 109 basins, including 32 adjudicated basins ranked as low- or very-low priority, account for approximately 98 percent of the groundwater used in California. Under the 2018 SGMA Basin Prioritization, 14 basins previously ranked as low- or very-low are now ranked as high- or medium-priority. These basins are now subject to SGMA. They are:

  • Mad River Valley basin-Mad River Lowland subbasin
  • Alexander Valley basin-Alexander Area subbasin
  • Santa Rosa Valley basin-Healdsburg Area subbasin
  • Wilson Grove Formation Highlands basin
  • Napa-Sonoma Valley basin-Napa Sonoma Lowlands subbasin
  • Santa Clara Valley basin-San Mateo Plain subbasin
  • Half Moon Bay Terrace basin
  • Westside basin
  • Carpinteria basin
  • Montecito basin
  • Ventura River Valley basin-Lower Ventura River subbasin
  • Upper Lake Valley basin
  • San Joaquin Valley basin-Pleasant Valley subbasin
  • Kern River Valley basin

Under the 2018 SGMA Basin Prioritization, 38 basins previously ranked as high- or medium-priority are now ranked low- or very-low priority and are no longer subject to SGMA. This includes 24 adjudicated basins that are required to submit annual reports. The non-adjudicated basins ranked as low- or very-low are:

  • Santa Clara Valley basin-East Bay Plain subbasin
  • West Santa Cruz Terrace basin
  • Santa Margarita basin
  • Elsinore basin-Bedford Coldwater subbasin
  • San Diego River Valley basin
  • Corralitos basin-Purisima Highlands subbasin
  • Tahoe Valley basin-Tahoe South subbasin
  • Borrego Valley basin-Ocotillo Wells subbasin
  • Salinas Valley basin-Atascadero Area subbasin
  • Arroyo Santa Rosa Valley basin
  • Redding Area basin-Bowman subbasin
  • Sacramento Valley-Dye Creek subbasin
  • Sacramento Valley-Los Molinos subbasin
  • Bear Valley basin

Under SGMA, high- and medium-priority basins are required to form Groundwater Sustainability Agencies (GSAs) and develop Groundwater Sustainability Plans (GSPs). When the 2018 SGMA Basin Prioritization is made final, the basins newly subject to SGMA must form GSAs within two years and adopt GSPs within five years or they must develop an approved alternative plan.

Low- or very-low priority basins are not subject to SGMA but are encouraged to form GSAs and GSPs, update existing groundwater management plans, and coordinate with adjacent basins to develop a new groundwater management plan.

DWR provides a wide variety of resources and services to support local agencies and GSAs in implementing SGMA. The department provides facilitation support, technical support services, and financial assistance. Other tools include access to data, mapping, modeling, maps, reports, and DWR’s newly launched SGMA Data Viewer and Natural Communities Commonly Associated with Groundwater Dataset Viewer.

DWR will conduct public meetings to gather additional data and information on the proposed prioritization.

For more information visit the basin prioritization website at https://www.water.ca.gov/Programs/Groundwater-Management/Basin-Prioritization





Lauren Bisnett, Information Officer

(916) 653-7564 | lauren.bisnett@water.ca.gov