Basin prioritization classifies California’s 517 groundwater basins (basins) into priorities based on components identified in the California Water Code Section 10933(b). The priority of basins determine the provisions that apply for the California Statewide Groundwater Elevation Monitoring (CASGEM) and Sustainable Groundwater Management Act (SGMA) programs in a basin. The prioritization process consists of applying datasets and information in a consistent, statewide manner in accordance to the provisions in the California Water Code.
DWR was first directed to prioritize basins as part of the Groundwater Monitoring legislation enacted in California's 2009 Comprehensive Water package. DWR prioritized groundwater basins through the CASGEM Program and released the results in 2014.
In 2015, SGMA went into effect and required DWR to prioritize basins for purposes of SGMA and to reassess the basin priority when DWR updates Bulletin 118 basin boundaries. In 2015, DWR implemented the 2014 CASGEM Basin Prioritization as the initial SGMA basin prioritization. In 2016, DWR received 54 requests for basin boundary modifications. DWR released the final groundwater basin boundaries, which incorporated numerous statewide jurisdictional and scientific modifications. On December 22, 2016, DWR published Bulletin 118 Interim Update 2016, which included the boundary modifications.
Finalization of the 2016 Basin Boundary Modifications documented in Bulletin 118 Interim Update 2016 required DWR to reassess the basin prioritization. In January 2019, DWR released the final basin prioritization for 458 of the 517 basins. The remaining 59 basins were affected by 43 basin boundary modification requests that were submitted between January and September 2018. The final basin prioritization for the remaining 59 basins will be released after basin boundaries are finalized.
2018 SGMA Basin Prioritization
The 2018 SGMA Basin Prioritization process and results are provided below.
Access the Results
|Basin Prioritization Dashboard
(online web map)
Process and Results Document
2018 SGMA Basin Prioritization
|Spreadsheets and data
at CNRA Open Data
Timeline and Next Steps
The following table is the anticipated schedule for finalizing the 2018 SGMA Basin Prioritization.
|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)||January 4, 2019|
|Prioritization based on 2018 Basin Boundary Modifications|
|Release of Draft Prioritization||Spring 2019|
|Public Comment Period and Public Meeting||Spring 2019|
|Release of Final Prioritization||Late Spring 2019|
*Last modified on 1/4/2019. All dates are subject to change.
Public Meetings and Comments
DWR accepted public comments following the release of the Draft 2018 SGMA Basin Prioritization Process and Results.
Frequently Asked Questions on Basin Prioritization
Answers to frequently asked questions provided below or in the Frequently Asked Questions on Basin Prioritization document.
Prioritization is the classification of groundwater basins based on a variety of factors identified in statute, such as population and the number of water wells in a basin (see Water Code § 10933). DWR was first directed to prioritize basins as part of the Groundwater Monitoring legislation adopted in 2009, which established the order in which DWR would evaluate basins to determine whether monitoring provided sufficient information to demonstrate seasonal and long‐term trends in groundwater elevations, as required by that law. DWR created the California Statewide Groundwater Elevation Monitoring (CASGEM) Program in response to the Groundwater Monitoring legislation, and released the CASGEM prioritization of basins in 2014. The Sustainable Groundwater Management Act (SGMA), which became effective in 2015, required DWR to prioritize basins for purposes of SGMA shortly after the law took effect (see Water Code § 10722.4). DWR implemented the 2014 CASGEM Basin Prioritization as the initial SGMA Basin Prioritization in 2015.
SGMA requires DWR to reassess groundwater basin prioritization any time it updates Bulletin 118 boundaries. Finalization of the 2016 Basin Boundary Modifications documented in Bulletin 118 Interim Update 2016 required DWR to reassess the basin prioritization. DWR’s reassessment indicated a need to prioritize basins whose SGMA compliance status was uncertain as a result of the basin boundary modifications, as well the need for reprioritization based on the presence of new and enhanced information, and the consideration of factors specifically relevant to SGMA.
DWR revised the 2018 SGMA Basin Prioritization after considering public comments received through three public meetings, a webinar, and online comment submittals during the 94-day comment period. DWR considered all comments received and made adjustments to the 2018 SGMA Basin Prioritization where commenters identified SGMA-related issues that the Department determined warranted reevaluation of the prioritization methodology or presented the Department with credible data that resulted in a reassessment of the priority of a basin. Most changes to basin prioritization are a result of modifications to the weight given to basins participating in groundwater-related transfers (8.d) and water quality impacts (7.d). Additional information regarding these sub-components is available in the 2018 SGMA Basin Prioritization Process and Results document available on DWR's website:
Other revisions to the 2018 SGMA Basin Prioritization included use of new data or information to improve understanding of basins and update prioritization calculations.
Final 2018 SGMA Basin Prioritization has been divided into two steps:
- Step 1 based on 2016 Basin Boundaries including 458 basins not affected by the 2018 Basin Boundary Modification requests.
- Step 2 will prioritize the 59 basin areas affected by the 2018 Basin Boundary Modification requests.
Step 1 of the Final 2018 SGMA Basin Prioritization was released in January 2019. Following the Final 2018 Basin Boundary Modifications, DWR will release draft Step 2 results, hold a public meeting, and will open a public comment period. The results of Step 2 of the Final 2018 SGMA Basin Prioritization is anticipated to be released in Spring 2019.
DWR prioritizes groundwater basins based on factors such as population, irrigated acreage, and the number of wells (see Water Code §10933). Most factors are neutral as to groundwater management, focusing simply on the importance of groundwater in a basin. As a result, a sustainably managed basin may be designated as high-priority based on which of these factors are present. Changes in status from the 2014 CASGEM Basin Prioritization generally reflects changed conditions or new information about existing conditions. Changes in status are not meant as a comment on changes to groundwater management in that basin.
Although SGMA applies to all basins in California, only high- and medium-priority basins are required to adopt a groundwater sustainability plan (GSP) or submit an alternative. Low- and very low-priority basins may adopt these plans, but are not required to. A low- or very low-priority basin reclassified as high- or medium-priority will be required to adopt a GSP or submit an alternative. A high- or medium-priority basin reclassified as low- or very low-priority will no longer be required to adopt a GSP or submit an alternative. SGMA does not treat low-priority basins differently than very low-priority basins. SGMA does not treat high-priority basins differently than medium-priority basins. For this reason, a change from medium- to high-priority does not affect requirements under SGMA.
DWR used the same process for the 2018 SGMA Basin Prioritization as was used for the 2014 CASGEM Basin Prioritization. A description of the prioritization process can be found in the following documents:
Water Code §10720.8 identifies adjudicated areas in SGMA, which have an existing defined entity administering the adjudication. Under SGMA, adjudicated portions of basins are exempt from developing a groundwater sustainability plan (GSP) and forming a groundwater sustainability agency (GSA). However, the entities administering the adjudications are subject to submitting annual reports to DWR by April 1 each year. SGMA requires that annual reports include the following information for the portion of the basin subject to adjudication:
a) Groundwater elevation data unless submitted pursuant to Water Code §10932.
b) Annual aggregated data identifying groundwater extraction for the preceding water year.
c) Surface water supply used for or available for use for groundwater recharge or in-lieu use.
d) Total water use.
e) Change in groundwater storage.
f) The annual report submitted to the court.
DWR accepts public comments following the release of draft results. DWR will conduct public meetings following the release of draft results from step 2 of the 2018 SGMA Basin Prioritization process. The final 2018 SGMA Basin Prioritization for step 2 will consider input received during the public comment period.
For more information regarding how to comment, visit the website at the following link:
Basins previously ranked as low- or very low priority that are prioritized as high- or medium-priority are subject to SGMA and have additional time to form Groundwater Sustainability Agencies (GSAs) and develop and implement GSPs or to submit an alternative (see Water Code § 10722.4(d)). If a basin is reprioritized from low or very low to high- or medium-priority, the following deadlines apply:
- Two years from Final Basin Prioritization to form a GSA
- Two years from Final Basin Prioritization to submit an alternative
- Five years from Final Basin Prioritization to develop a GSP
Basins previously prioritized as high- or medium-priority that are now low- or very low-priority are not subject to the requirements in SGMA to form a GSA and prepare a GSP or an alternative to avoid potential State Water Resources Control Board intervention. However, these basins are still encouraged to form GSAs and develop GSPs, update existing groundwater management plans, and coordinate with others to develop a new groundwater management plan in accordance with Water Code Section 10750 et seq.
DWR provides a variety of services and support to GSAs including Facilitation Support, Technical Support Services, Communication and Engagement, and Financial Assistance.
Basin Points of Contact
DWR has designated Basin Points of Contacts (POCs) to assist local agencies as GSPs are developed and implemented. Once the 2018 SGMA Basin Prioritization is finalized, POCs will be identified for those new high- and medium-priority basins. For more information, please contact your DWR regional office representatives identified below:
- Northern Region: Bill Ehorn, Bill.Ehorn@water.ca.gov, (530) 528-7403
- North Central Region: Bill Brewster, Bill.Brewster@water.ca.gov, (916) 376-9657
- South Central Region: Dane Mathis, Dane.Mathis@water.ca.gov, (559) 230-3354
- Southern Region: Tim Ross, Timothy.Ross@water.ca.gov, (818) 549-2345
DWR has developed a suite of data, tools, guidance documents, and references to assist in the development and implementation of GSPs. Throughout the SGMA implementation horizon, DWR will continue to develop relevant and useful tools with open access to necessary data and scientific information, in addition to providing access to Basin Points of Contacts. Resources available now include:
- Monitoring Well Installation
- Groundwater Level Monitoring Training
- Borehole Video Logging
- Other Field Activities
- Identification and engagement of interested parties
- Meeting facilitation
- Interest-based negotiation/consensus building
- Public outreach facilitation
- DWR Region Office Contacts
- Communication and Engagement Digital Toolkit
- Integrated Regional Water Management
- Water Quality or Drinking Water
- Water Supply or Management
- Water Use Efficiency
DWR offers a variety of services and assistance to support GSA development of GSPs. DWR is funding Technical Support Services and Facilitation Support Services to aid GSAs that includes meeting facilitation, field activities, modeling and mapping.
In addition to the technical and facilitation support, DWR offers several Integrated Regional Water Management (IRWM) Grant programs. IRWM Grant programs fund planning, implementation, and disadvantaged community involvement. At this time, there are no additional Proposition 1 funds remaining for the Sustainable Groundwater Planning Grant program; however, DWR may administer another round of solicitation should any new funds become available. There are additional grant programs with open solicitations available which may be applicable.
Yes, GSAs or local agencies who received grants from the Sustainable Groundwater Planning Grant Program have the option to use the funding to proceed with development and adoption of a GSP and the project scope defined in the grant agreement or to return the funding to DWR.
The Department does not have the authority to extend the deadlines associated with submittal of GSPs, as defined in Water Code § 10720.7.
The 2014 CASGEM Basin Prioritization establishes the basin priority until the 2018 SGMA Basin Prioritization is final. The 2018 SGMA Basin Prioritization was finalized in January 2019 for basins not affected by basin boundary modifications, and is anticipated to be finalized in Spring 2019 for basins affected by a basin boundary modification request. The 2018 SGMA Basin Prioritization process does not affect statutory deadlines for basins, unless a basin’s priority changes from high or medium to low or very low.
In January 2014, we conducted five public comments. Final 2014 Basin Prioritization results are compiled into a . You can also visit our , a web-based application that includes a layer depicting Basin Prioritization information.to introduce draft 2014 Basin Prioritization results and solicit
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):
- Rate of population growth
- Number of public supply wells
- Total number of wells
- Total irrigated acreage
- Degree to which persons overlying the basin rely on groundwater as their primary source of water
- Documented impacts on the groundwater within the basin, including overdraft, subsidence, saline intrusion, and other water quality degradation
- 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).