Calvin Lagoon Wastewater Treatment Plant, Winn Parish, Louisiana

Calvin Lagoon is a wastewater treatment facility located in Winn Parish, Louisiana, United States. The plant serves a small population of 207 residents, providing secondary treatment for municipal wastewater. It operates as a lagoon system, a common treatment method for rural communities in the region. The plant has a designed capacity of 151.42 m³/day and currently treats a daily flow of 75.71 m³/day. As a secondary treatment facility, it meets the minimum standards required by the US Clean Water Act for municipal wastewater treatment. The plant is regulated under the National Pollutant Discharge Elimination System (NPDES) permit program, administered by the Louisiana Department of Environmental Quality. The treated effluent from Calvin Lagoon is discharged into local streams that drain into the Ouachita River basin. The Ouachita River flows southward through Louisiana, eventually reaching the Mississippi River and the Gulf of Mexico. The plant's discharge contributes to the overall water quality in this watershed, which supports diverse aquatic life and recreational activities.

Calvin Lagoon discharges into small tributaries of the Ouachita River, which flows through central Louisiana and joins the Mississippi River before reaching the Gulf of Mexico. The watershed supports a variety of fish and wildlife species, including catfish, bass, and waterfowl. The region's flat terrain and slow-moving rivers make water quality sensitive to nutrient loading, which can lead to algal blooms and oxygen depletion.