Harrison S_T Facility Wastewater Treatment Plant, Harrison, Idaho

The Harrison S_T Facility is a municipal wastewater treatment plant located in Harrison, Idaho, within Kootenai County. Serving a small population of 203, the plant provides secondary treatment to meet state and federal water quality standards under the U.S. Clean Water Act. As a secondary treatment facility, the plant uses biological processes to reduce organic matter and suspended solids. With a designed capacity of 132.49 million gallons per day and an average discharge volume of 71.92 million gallons per day, the plant operates well within its capacity. The U.S. EPA's National Pollutant Discharge Elimination System (NPDES) permit program governs its discharge, ensuring compliance with water quality criteria. The plant's treated effluent enters the local drainage network, which flows into the Coeur d'Alene River and ultimately into Coeur d'Alene Lake. This lake is a vital ecological and recreational resource in northern Idaho, supporting diverse aquatic life and serving as a key water body in the Spokane River basin. The plant's operations help protect downstream water quality and ecosystem health.

The plant discharges into the Coeur d'Alene Lake watershed, part of the larger Spokane River system that drains into the Columbia River and eventually the Pacific Ocean. Coeur d'Alene Lake is a deep, oligotrophic lake that supports cold-water fish species and provides critical habitat for migratory waterfowl. The region's mountainous terrain and seasonal snowmelt influence flow patterns, making consistent treatment essential to prevent nutrient loading and maintain water clarity.