Shoal Lake Lagoon Wastewater Treatment Plant, Rural Municipality of Yellowhead, Manitoba

Shoal Lake Lagoon is a municipal wastewater treatment facility located along Provincial Trunk Highway 21 in the Rural Municipality of Yellowhead, Manitoba, Canada. The plant serves a small population of 766 residents and operates under secondary treatment standards, typical for rural communities in the Canadian Prairies. As a secondary treatment facility, Shoal Lake Lagoon provides biological treatment to reduce organic matter and suspended solids before discharge. The plant's annual discharge volume of 343.70 megaliters reflects the scale of a small agglomeration. In Canada, wastewater treatment is regulated under the federal Wastewater Systems Effluent Regulations (WSER) and provincial environmental acts, which set effluent quality standards for facilities of this size. The treated effluent from Shoal Lake Lagoon is discharged into the local watershed, which ultimately drains into the Assiniboine River and then into the Lake Winnipeg basin. This region is part of the larger Nelson River drainage system, which flows into Hudson Bay. The plant plays a key role in protecting downstream water quality in this ecologically sensitive prairie landscape.

Shoal Lake Lagoon discharges into a local watercourse that flows into the Assiniboine River, a major tributary of the Red River. The Red River drains into Lake Winnipeg, a large and ecologically important lake that experiences eutrophication from nutrient loading. The plant's secondary treatment helps reduce nutrient and organic pollutant loads, supporting the health of downstream aquatic ecosystems in the Lake Winnipeg basin.