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

Westside basin

Alexander Valley basin-Alexander Area subbasin

Carpinteria basin

Santa Rosa Valley basin-Healdsburg Area subbasin

Montecito basin

Wilson Grove Formation Highlands basin

Ventura River Valley basin-Lower Ventura River subbasin

Napa-Sonoma Valley basin-Napa Sonoma Lowlands subbasin

Upper Lake Valley basin

Santa Clara Valley basin-San Mateo Plain subbasin

San Joaquin Valley basin-Pleasant Valley subbasin

Half Moon Bay Terrace basin

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

Borrego Valley basin-Ocotillo Wells subbasin

West Santa Cruz Terrace basin

Salinas Valley basin-Atascadero Area subbasin

Santa Margarita basin

Arroyo Santa Rosa Valley basin

Elsinore basin-Bedford Coldwater subbasin

Redding Area basin-Bowman subbasin

San Diego River Valley basin

Sacramento Valley-Dye Creek subbasin

Corralitos basin-Purisima Highlands subbasin

Sacramento Valley-Los Molinos subbasin

Tahoe Valley basin-Tahoe South 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