Garrison Lagoon Wastewater Treatment Plant, Garrison, North Dakota

Garrison Lagoon is a municipal wastewater treatment facility located in Garrison, McLean County, North Dakota. The plant serves a population of approximately 1,453 residents and operates as a lagoon-based secondary treatment system. Its location near the Missouri River places it within a region characterized by semi-arid climate and agricultural land use. The plant provides secondary treatment, which is the standard for small communities under the U.S. Clean Water Act. With a designed capacity of 681.37 thousand cubic meters and an annual discharge volume of 567.81 thousand cubic meters, the facility operates at a utilization rate that suggests adequate capacity for its service area. As a publicly owned treatment works (POTW), it is subject to National Pollutant Discharge Elimination System (NPDES) permitting, ensuring compliance with effluent limits. The treated effluent from Garrison Lagoon ultimately drains into the Missouri River basin, a major tributary of the Mississippi River system. The Missouri River supports diverse aquatic life and provides drinking water for downstream communities. The plant's discharge contributes to the river's flow, and its secondary treatment helps protect water quality in this ecologically significant watershed.

The plant discharges into the Missouri River watershed, which flows into the Mississippi River and eventually the Gulf of Mexico. This river system supports a variety of fish species and provides critical habitat for migratory birds. The semi-arid climate of North Dakota means that maintaining water quality in the Missouri River is essential for both ecological health and human use, including irrigation and recreation.