We are pleased to announce the launch of the Cosumnes Groundwater Authority’s new website: 

Over the next couple of months, we will gradually transition from to this new website. Check out the new website and be sure to bookmark it for future reference!

If you have any questions regarding the Cosumnes Groundwater Authority please contact Austin Miller, Cosumnes Subbasin Groundwater Sustainability Plan Interim Plan Manager and CGA Administrator, at 916-526-5447 or

Questions about an upcoming event?

Contact Stephen Julian at or 254.640.0155

Si necesita solicitar alojamiento para asistir a un próximo evento, incluidos los servicios de traducción, comuníquese con Stephen Julian a o al 254.640.0155

Cosumnes GSA Groups and Meeting Descriptions

Cosumnes Groundwater Authority

About: In November 2021, the 7 Groundwater Sustainability Agencies (GSAs) within the Cosumnes Subbasin formed the Cosumnes Groundwater Authority (CGA). The CGA is charged with the responsibility of implementing the Cosumnes Subbasin Groundwater Sustainability Plan in compliance with the Sustainable Groundwater Management Act (SGMA).

View the (unsigned) documents for 1) Joint Powers Authority (JPA) agreement to form the Cosumnes Groundwater Authority for GSP implementation, and 2) an Initial Funding and Revenue Agreement 

Click here for more CGA updates and meeting information

Cosumnes Subbasin SGMA Working Group (2016-2021)

About: The seven GSAs in the subbasin are working together as the Cosumnes Subbasin SGMA Working Group (Working Group) to develop one or more groundwater sustainability plans (GSPs) by Jan 31, 2022. The Working Group is guided by a near-term framework agreement that describes how the GSAs will work together through GSP development.

View Working Group Framework Agreement for GSP Development: Phases 1 + 2 | Phases 3 + 4  

With the GSAs Boards’ adoption of the Cosumnes Subbasin GSP, the Working Group held its final meeting January 19, 2022. The CGA oversees GSP implementation.

Click here for past Working Group meeting materials

Other Past Working Group Committees

About: Working Group committees were internal meetings* where GSA representatives develop recommendations for the Working Group’s consideration and final decision making. Below are recent updates from the currently active committees; additional and past information can be found with the Working Group meeting materials. (*Long-Term Governance meetings are open to the public as of March 2021) . 

These committees sunsetted with the Working Group in January 2022. Refer to the new website ( for active committees.

    • Long-Term Governance / Implementation Committee
    • Outreach & Engagement Committee
    • GSP Ad Hoc Committee
    • Projects & Management Actions (P/MAs) Subcommittee

Technical Advisory Committee*

About: The Working Group formed a Technical Advisory Committee (TAC), which is tasked with developing recommendations to the Working Group on technical issues related to SGMA implementation. 

 *The Technical Advisory Committee (TAC) to the Cosumnes SGMA Working Group does not currently meet separately from the Working Group.

> Click here for past meeting materials

Stakeholder Advisory Groups Meeting Descriptions

Citizens Advisory Committee

Formed in 2022. Visit the new website for more information

Surface Water Advisory Group

About: The Surface Water Advisory Group (SWAG) served an advisory role to the Working Group to inform the Working Group’s development of the Cosumnes Subbasin GSP. The group’s objective is to develop mutual understanding of the technical basis for sustainable management criteria related to groundwater/surface water interactions. The SWAG met four times between July 2020-March 2021. 

> Click here for upcoming/past meeting materials

Stay Connected

Refer to the new website –