Big Swan Lake Feasibility Study

ISG collaborated with the Big Swan Lake Improvement District, Todd County Soil and Water Conservation District, the U.S. Fish & Wildlife Service, and The Nature Conservancy to evaluate restoration strategies for the Schwanke Creek wetland at the outlet to Big Swan Lake. The TMDL study identified Schwanke Creek is the largest external source of phosphorus to the lake, and the goal of this feasibility study was to identify the preferred restoration approach to address this issue. Options explored included sediment scrapes, alum treatment, channel re-meander, and water control structures.

Through soil, vegetation, and hydrologic assessments, the team proposed a delta restoration, which offers a nature-based, process-driven approach that focuses on restoring the creek and wetland to a dynamic, self-regulating system. This approach would create distributary channels, use low-technology process-based structures, and expand wetland functions to slow water, capture sediment, reduce phosphorus exports, and support diverse habitats.

The preferred concept is projected to reduce phosphorus loading by more than 44 pounds per year while enhancing biodiversity and ecological resilience. The study also outlined cost estimates, permitting needs, construction considerations, and funding opportunities to position local partners for implementation and long-term water quality improvement. The project is the first in Minnesota to apply a delta restoration approach, showing how nature-based design can increase phosphorus removal, support biodiversity, and offer a sustainable, long-term solution.