Three Forks STP Wastewater Treatment Plant, Gallatin County, Montana

Three Forks STP is a municipal wastewater treatment plant located in Gallatin County, Montana, serving a population of approximately 1,869 residents. The facility is situated near the town of Three Forks, at the headwaters of the Missouri River, where the Jefferson, Madison, and Gallatin rivers converge. As a small-scale treatment plant, it plays a key role in managing local wastewater for this rural community. The plant operates under the U.S. Clean Water Act, which requires secondary treatment for municipal wastewater facilities. For a plant serving fewer than 10,000 people, typical treatment includes biological processes such as activated sludge or lagoon systems, followed by disinfection. Its population equivalent suggests a moderate flow. The treated effluent is discharged into a receiving water body within the Missouri River basin, which ultimately flows into the Mississippi River and the Gulf of Mexico. The plant's operations help protect local water quality in the headwaters region, which supports diverse aquatic life and recreational uses. The surrounding area is primarily agricultural and rural, with sensitive groundwater and surface water resources.

The plant discharges into the Missouri River headwaters, where the Jefferson, Madison, and Gallatin rivers converge. This region is ecologically significant as the source of the Missouri River, supporting cold-water fisheries and migratory bird habitats. Downstream, the river flows through Montana and into the Mississippi River system, eventually reaching the Gulf of Mexico. Protecting water quality here is critical for maintaining aquatic biodiversity and downstream ecosystem health.