RIDGEWAY WSL Wastewater Treatment Plant, Winneshiek County, Iowa

RIDGEWAY WSL is a municipal wastewater treatment facility located in Lincoln Township, Winneshiek County, Iowa. The plant serves a small population of 295 residents and is part of the region's rural wastewater infrastructure. Its location in northeastern Iowa places it within the Upper Mississippi River basin. The plant provides secondary treatment, which is the standard minimum level required under the US Clean Water Act for municipal wastewater facilities. With a designed capacity of 113.56 megaliters and an annual discharge volume matching that figure, the plant operates at full capacity. The US Environmental Protection Agency's National Pollutant Discharge Elimination System (NPDES) permit program governs such facilities, ensuring compliance with water quality standards. The treated effluent from RIDGEWAY WSL ultimately drains into the Upper Mississippi River watershed, which flows south to the Gulf of Mexico. This region supports diverse aquatic life and is an important migratory corridor for waterfowl. The plant's secondary treatment helps protect local streams and rivers from nutrient pollution and pathogens.

The plant discharges into local tributaries of the Upper Mississippi River, which flows through the Driftless Area of Iowa, a region known for its spring-fed streams and diverse aquatic habitats. The Mississippi River eventually reaches the Gulf of Mexico, where nutrient loading contributes to seasonal hypoxia. The plant's secondary treatment reduces organic pollutants and helps maintain water quality in this ecologically sensitive watershed.