Basin Prioritization

DRAFT 2018 SGMA Basin Prioritization
DRAFT 2018 SGMA Basin Prioritization

Basin prioritization classifies the California’s 517 basins and subbasins into priorities based on components identified in the California Water Code. The priority of basins and subbasins determines whether CASGEM and SGMA provisions apply in any given basin. The priority process consists of applying datasets and information in a consistent, statewide manner in accordance to the provisions in California Water Code Section 10933(b).

In 2014, DWR prioritized groundwater basins through its California Statewide Groundwater Elevation Monitoring (CASGEM) Program, which was established in response to the legislation enacted in California's 2009 Comprehensive Water package. The 2014 CASGEM Basin Prioritization classified basins as high, medium, low, or very low based on the consideration of factors described in the legislation.

Following the adoption of Sustainable Groundwater Management Act (SGMA) and the Basin Boundary regulations, DWR received 54 requests for basin boundary modifications. In the fall of 2016, DWR completed and released the final groundwater basin boundaries, which incorporated numerous statewide jurisdictional and scientific modifications. DWR published Bulletin 118 – Interim Update 2016, which included the boundary modifications, on December 22, 2016.

The SGMA requires that DWR reassess the prioritization anytime DWR updates Bulletin 118 basin boundaries. The 2018 SGMA Basin Prioritization process and draft results are provided below.

2018 SGMA Basin Prioritization

Following the release of the 2016 Basin Boundary Modifications, DWR began the 2018 SGMA prioritization of California’s 517 groundwater basins (Water Code 12924(b)) defined in Bulletin 118. Prioritization has changed for some basins due to the consideration of impacts from local habitat and local streamflows, the change in area of basin as a result of boundary modifications, and incorporation of newly available data sources. DWR will conduct public meetings to present the draft results and solicit public comments.

How to Access the Results

The 2018 SGMA Basin Prioritization process and draft results can be accessed below:


 mapping-application Document  Open Data
Basin Prioritization Dashboard
(online web map)
2018 SGMA Basin Prioritization
Process and Draft Results document

Spreadsheets and data
at CNRA Open Data


View Statewide Figure of DRAFT 2018 SGMA Basin Prioritization

Timeline and Next Steps

The following table is the anticipated schedule for finalizing the 2018 SGMA Basin Prioritization.

Events Dates*
 Prioritization based on 2016 Basin Boundary Modifications  
 Public Comment Period Opens May 18, 2018
 Webinar May 30, 2018
 Public Meetings June 25-28, 2018
 Public Comment Period Closes August 20, 2018
 Finalize Prioritization (based on 2016 Basin Boundary Modifications) mid-November
 Prioritization based on 2018 Basin Boundary Modifications  
 Release of Draft Prioritization for Modified Basins late February
 Public Comment Period February - March
 Release of Final Prioritization (based on 2018 Basin Boundary Modifications) May 2019

  *Last modified on 7/24/2018. All dates are subject to change.


View Detailed 2018 SGMA Basin Prioritization Timeline Graphic

Public Meetings and Comments

Public meetings will be held to go over the process and solicit public comments on the draft results.

View Public Meetings


The public comment period opened on May 18, 2018 and closed after 90 days on August 20, 2018. Statewide data consistent with the 2018 SGMA Basin Prioritization Process and Results document may be provided in support of comments.

View Submitted Public Comments    Submit New Public Comment (Closed)


Frequently Asked Questions on Basin Prioritization

Answers to frequently asked questions provided below or in the Frequently Asked Questions on Basin Prioritization document.

In January 2014, we conducted five workshops to introduce draft 2014 Basin Prioritization results and solicit public commentsFinal 2014 Basin Prioritization results are compiled into a summary table  available in PDF or Excel formatYou can also visit our Groundwater Information Center Interactive Map, a web-based application that includes a layer depicting Basin Prioritization information.

CASGEM BP 2014 Final Table
CASGEM Basin Prioritization 2014 Final Results ( XLSX) | (Publish Date:
Detailed spreadsheet of 2014 Final Basin Prioritization Results which includes values used in determining the individual component ranking values, organized by basin number.
CASGEM BP Process 2014
CASGEM Basin Prioritization Process 2014 ( PDF) | (Publish Date:
This report provides a detailed explanation of the Basin Prioritization Process and includes an appendix with figures and tables describing 2014 Basin Prioritization results.
CASGEM BP Brochure
CASGEM Groundwater Basin Prioritization Brochure ( PDF) | (Publish Date:
Brochure summarizing Basin Prioritization criteria and process.
CASGEM Basin Prioritization FAQ ( PDF) | (Publish Date:

The Water Code requires a statewide prioritization, to the extent that data are available, of California's groundwater basins using the following eight components (Water Code §10933):


  1. Population
  2. Rate of population growth
  3. Number of public supply wells
  4. Total number of wells
  5. Total irrigated acreage
  6. Degree to which persons overlying the basin rely on groundwater as their primary source of water
  7. Documented impacts on the groundwater within the basin, including overdraft, subsidence, saline intrusion, and other water quality degradation
  8. Any other information determined to be relevant by the department, including adverse impacts on local habitat and local streamflows

A priority designation of high, medium, low, or very low is assigned to each groundwater basin. For details on how changes in priority affect local agency compliance with SGMA, refer to establishment of Groundwater Sustainability Agencies (GSAs).