Sustainable Groundwater Management Act


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* May 2017: Subbasin moving forward with joint GSA + Vacaville, SID GSAs (Northern Delta GSA TBD)

After much deliberation, the Solano Subbasin has moved from the originally proposed single GSA format to a multi-GSA, with Solano Irrigation District and the City of Vacaville, as large water purveyors in the subbasin, each filing to form their own GSAs. At the same time, the GSA informed by the 2016-2017 public input process will continue to move forward, and all parties in the subbasin are developing a memorandum of understanding for ongoing collaboration and coordination for groundwater sustainability planning and management of the subbasin. Key highlights:

  • The Solano Irrigation District GSA is moving forward as filed in early 2017, as a single agency GSA. You can review their GSA information here on the Department of Water Resources SGMA Portal.
  • The Vacaville GSA public hearing was held April 25th. You can read more about this board decision in this news article.
  • The Joint Powers Authority JPA legal document has been finalized for an 11 member board (see below).
  • The Solano Subbasin Joint Powers Authority GSA will hold its public notice hearing to finalize the commitment to form the GSA on June 8th, 2017 at 4:00 pm at the Solano County Water Agency (SCWA) office (810 Vaca Valley Parkway, Suite 203, Vacaville CA 95688).
  • Written comments can be submitted to Chris Lee at SCWA no later than 4:00 on June 8th ( for email submissions).

Revised Joint GSA membership: City of Dixon, City of Rio Vista, Solano County District 4, Solano County District 5, Dixon RCD, Solano RCD, Maine Prairie Water District, Reclamation Distriction 2068, Cal Water (via MOU), Public Agriculture Representative #1 (nominated by the Solano County Farm Bureau), Public Agriculture Representative #2 (nominated by the Solano County Ag Advisory Committee and appointed by the Board of Supervisors).

Of the originally presented 16 member structure, the following five parties have voluntarily opted out: 

  • City of Fairfield: opted out of board seat due to low groundwater usage
  • Rural North Vacaville Water Distict: opted out of board seat due to low groundwater usage
  • City of Vacaville: forming single-agency GSA
  • Solano Irrigation District: forming single-agency GSA
  • North Delta Water Agency: opted out of board seat, possible advisory committee role, TBD depending on Northern Delta GSA status

Over the last few weeks, the SID, Vacaville, and Joint GSA groups have worked together to clarify GSA boundaries to avoid any concerns of boundary overlap or white spaces (uncovered areas) in the subbasin. The Northern Delta GSA will make it’s final decision on whether to form before the joint GSA June 8th public hearing. If this group does not form in time for the June 30th deadline, its members will be represented by their corresponding area GSAs (Solano Subbasin GSA and the Sacramento GSA). The subbasin is set to meet the June 30th 2017 filing deadlines.

* February 2017: GSA Prospective Board Workshop

In February 2017, prospective board members and alternates for the recommended 16-member GSA board for the Solano Subbasin came together to learn about SGMA, the recommended governance structure and guiding principles, next steps, and public input received to date. This was an informational workshop and not a decision-making forum. The material covered was similar to the December public input meetings, with a few updates from prospective member agencies and financial estimates. Most notable is the recent decision of the Solano Irrigation District to file a GSA application for their portion of the subbasin (not including areas within city limits). After a public hearing in January about this GSA proposal, SID submitted an application to DWR in February. (They continued conversation with others in the Solano JPA-agreement based group on pathways to stay involved in the full-group GSA as per the GSAG recommendations, but decided in the end to move forward with their application for single-GSA status). More details on this and other updates available in the presentation slides and meeting notes


Overview of SGMA

This factsheet provides a summary of SGMA and what it means for us in the Solano Subbasin. It includes most of the information that you will find on this webpage. See also the Solano Subbasin FAQs for answers to many common SGMA questions.     

The Sustainable Groundwater Management Act (SGMA), which went into effect on January 1, 2015, established a robust framework for the sustainable management of groundwater resources for the first time in California’s history. Groundwater is a critical component of the state’s water supply portfolio, and if effectively managed, this resource will help protect communities, farms, and the environment against the impacts of prolonged dry periods and climate change. SGMA recognizes that management is most effective when done at the local level by local agencies with adequate information, tools, resources, and authorities.

SGMA requires medium- and high-priority groundwater basins in the state to be managed by local agencies that have formed a Groundwater Sustainability Agency (GSA) by June 30, 2017. Once formed, a GSA must develop and implement a Groundwater Sustainability Plan (GSP) by January 31, 2022 to guide the sustainable management of its groundwater basin. The GSA has 20 years following this date to achieve its sustainability goals. The law allows for limited state intervention when necessary to protect groundwater resources.

SGMA Implementation Timeline

Forming a Groundwater Sustainability Agency 

The first step in implementing SGMA is to develop Groundwater Sustainability Agencies (GSAs), and this is a primary concern of agencies and stakeholders statewide at this time. SGMA defines a GSA as one or more local agencies that must implement SGMA’s provisions. A local agency is defined as any local public agency that has water supply, water management, or land use responsibilities within a groundwater basin. Any local agency or combination of local agencies overlying a groundwater basin can elect to be a GSA. A combination of local agencies may form a GSA by using any of the following methods: a joint powers agreement (JPA), or a memorandum of agreement or other legal agreement (MOU). A water corporation regulated by the Public Utilities Commission or a mutual water company may participate in a GSA through a memorandum of agreement or other legal agreement. Non-agency parties can be incorporated into the decision-making process for the GSA, or in certain cases, they may wish to form a new GSA-eligible agency.

An interactive GSA map showing the location of local agencies that have elected to be a GSA is available here.

What's Happening in Solano County?

In Solano County, the state has designated the Solano Subbasin as medium-priority, and thus subject to SGMA. The Solano Subbasin is contained mostly within Solano County, but portions are also within Sacramento and Yolo Counties. It underlies the Cities of Dixon, Fairfield, Rio Vista, and Vacaville, and is pumped regularly for local agricultural and municipal uses. Learn more about the current groundwater conditions in the Solano Subbasin. The two other groundwater basins in Solano County - the Suisun-Fairfield Valley Basin and the Napa-Sonoma Lowlands Subbasin - are not designated as priority basins, so are not subject to SGMA.


Download a detailed map of the Solano Subbasin displaying local public agency service areas and other details.

 The formation of a GSA(s) in the Solano Subbasin that have the widespread support of the eligible agencies, groundwater users, and stakeholders requires two interrelated processes:

  1. Inter-agency coordination: The convening of GSA-eligible agencies to identify and implement an appropriate long‐term governance approach for the GSA.
  2. Public stakeholder engagement: The engagement of groundwater users and other stakeholders to ensure that local concerns and interests are included in the GSA and GSP formation processes.

What Are Local Agencies Doing? 

Local agencies are expected to collaborate and coordinate their GSA formations on a basin-wide scale to sustainably manage groundwater at a local level. The Solano County Water Agency (SCWA) hired a facilitation team, Ag Innovations, to support this process, and in 2016 and early 2017, the facilitators worked with representatives from GSA-eligible agencies in the Solano Subbasin to identify agency interests, concerns, and recommendations relating to GSA formation, and to develop recommendations for the governance structure for one or more GSAs. In early 2016, a Groundwater Sustainability Agency (GSA) Advisory Group of local water-purveying agencies and local agriculture representatives came together to develop recommendations for the Solano Subbasin GSA governance structure to be submitted to DWR by June of 2017. After six months of research, deliberation, and agency and public input, the group made the following recommendations:

  • A single GSA for the Solano County portion of the Solano Subbasin
  • An inclusive GSA board with 16 members: 12 seats for local water-purveying agencies (including two for the Dixon and Solano RCDs), two County Supervisor seats, and two agriculture community seats
  • Governance via a Joint Powers Authority (the GSA would not be a single agency, and this structure allows public stakeholder members to vote on the board)
  • Governance using principles for GSA and Groundwater Sustainability Plan (GSP) development, based on group deliberations, Ag Summit input, and examples from other GSA development processes around the state.

View the Advisory Group Recommendations here. These recommendations were presented to agency boards and the public. Legal team and board deliberations in early 2017 resulted in a shift to a multiple-GSA governance structure for the subbasin, with a joint GSA with 11 board seats (still including two agriculture representative seats) operating in accordance with the above recommendations, and separate single-agency GSAs for the large water purveyors of the City of Vacaville and the Solano Irrigation District. 

Assuming approval of applications from the state, after June 2017, these three GSA agencies will seek continuous input from and coordinate with other agencies and public stakeholders, as stipulated by SGMA. 

Local SGMA Implementation Process Highlights:    

How Can Interested Stakeholders Get Involved?

Successful implementation of SGMA will support the health and vibrancy of the region’s communities, farms, and environment while maintaining local control over local groundwater resources. A substantial amount of groundwater use in the Solano Subbasin occurs on farms, and to a lesser extent on rural residences, thus the sustainable management of groundwater requires that local agencies and groundwater users work closely with one another from the start. Toward this end, SCWA and its partner agencies are working with a facilitator to solicit the input of farmers and ranchers, well-owners, businesses, environmental groups, and other stakeholders during the GSA formation process. This stakeholder engagement process will be used to understand and involve groundwater users and other interested parties and their concerns in the SGMA implementation process. 

Ways to get involved:

  1. Public workshops and other events: will be held periodically throughout the process to share information about SGMA and local groundwater conditions, and to ensure that stakeholder concerns and interests are heard during the GSA formation process. Join our listserv (top of page) to stay informed of upcoming events and input opportunities. 
  2. Email newsletter: email info [at] to receive periodic email updates about SGMA implementation in the Solano Subbasin, including invitations to meetings and important SGMA information.


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