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Basin Boundary Modifications

New!List of Draft Approved Basin Boundary Modifications - explanation of recommended modifications and link to original BBMRS submittal.
New!Map of Draft Approved Basin Boundary Modifications - to view draft approved basin boundary modifications select the "Draft Bulletin 118 Basins (2016 Edits)" layer.
New!Technical Memorandum - 2016 Draft Basin Boundary Modification Recommendations

The Sustainable Groundwater Management Act (SGMA) established a process for local agencies to request that the Department of Water Resources (DWR) revise the boundaries of existing groundwater basins or subbasins, including the establishment of a new subbasin. The Basin Boundary Emergency Regulation was developed through an extensive stakeholder outreach process and was adopted on October 21, 2015. The provisions of the emergency regulation go into effect on November 16, 2015.

Following the adoption of DWR’s Basin Boundary Emergency Regulations, DWR provided an online Basin Boundary Assessment Tool (BBAT) to inform local agencies and the public about the existing Bulletin 118 groundwater basins and other relevant geologic and geographic data. DWR’s Basin Boundary Modification Request System (BBMRS) enables local agencies to submit their requests for basin boundary modifications online and the public to view those requests and provide comment.

Draft Approved Basin Boundary Modifications

The Draft Approved Basin Boundary Modifications were developed through DWR’s technical review of basin boundary modification requests and public comment made during the submission period, January 1, 2016 through March 31, 2016. Future basin boundary modification submission periods will likely be based on demand and coordinated with 5-year updates to Bulletin 118.

DWR held a series of public meetings to present the Draft Approved Basin Boundary Modifications, provide an overview of the BBMRS and technical review process, answer clarifying questions and receive further public comments on the Draft Approved Basin Boundary Modification submissions.

New!Links to Public presentations of Draft Approved Basin Boundary Modifications

Next Steps

After the July public meetings, the public comments were summarized and presented to the California Water Commission. Following consideration and potential incorporation of comments heard, DWR will publish the final basin boundary modifications. In accordance with SGMA, these new basin definitions will be evaluated under the basin prioritization process and documented in the interim update of Bulletin 118, expected later this year.

Events Schedule*
Final Basin Boundary Modifications Published September, 2016
Interim Update of Bulletin 118 September, 2016
Presentation of Final Approved Basin Boundary Modification to CWC October 18, 2016

*All dates are subject to change.

Basin Boundary Modification Resources




More Information

Click here to sign up to receive email updates on Basin Boundary Modification Requests and DWR SGMA activities.

For additional information regarding basin boundary modifications, please contact Tim Godwin at or 916-651-9223.