Controlled Groundwater Areas

The July 2026 Gallatin Water Collaborative meeting focused on Controlled Groundwater Areas (CGWAs), a Montana statutory tool that allows DNRC to manage groundwater use within a designated area when quantity or quality concerns threaten water rights holders or surface water availability. Kerri Strasheim, Regional Manager of the Montana Department of Natural Resources and Conservation’s (DNRC) Bozeman Water Resources Office, provided an overview of how CGWAs work, who can petition for one, and what it would take to pursue one in the Gallatin Valley.

Key Takeaways:

• Conditions in the Gallatin Valley that make a CGWA worth considering include the over-appropriation of the West Gallatin, increasing exempt well density, and the hydrological connection between groundwater and surface water

• A strong scientific foundation is a prerequisite to petition for a CGWA.

• Control provisions (use/volume restrictions, mitigation/monitoring requirements, etc.) are flexible. CGWAs are not one-size-fits-all.

• Eligible petitioners include municipalities, counties, conservation districts, water quality districts, public health agencies, and organized groups of concerned water users.

• The petition process takes time.

• Community familiarity with the tool and the process matters as much as the science.

Meeting Resources:

• Agenda

• Notes

• Full Recording

Controlled Groundwater Area Resources:

• MCA 85.2.5: Controlled Groundwater Areas

• Montana’s Closed Basins and Controlled Groundwater Areas

• More Information Controlled Groundwater Area - DNRC website

• WPIC (Water Policy Interim Committee) Recordings

• Preliminary Exempt Well Data (Including a Gallatin Valley Aquifer section)

• New Exempt Well Process

• Vulnerable Wells in the Gallatin Valley - GLWQD

• Gallatin Aquifer & Stream Study (GASS) - DNRC

• Hay Thesis (1997, MSU)