South Lake

South Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Mesotrophic conditions dominate at South Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. South Lake is unusually deep for Minnesota at 140 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. With 1,145 acres of surface and 15.0 miles of shoreline, South Lake is a large water by Minnesota standards — recreational pressure is spread across a long shoreline. South Lake sits at rank 87 of 128 in Cook County, in the lower half of the local distribution.

South Lake has no invasive species recorded in Minnesota state databases as of 2023, though prevention practices still apply at all access points. The fishery is bass-led, with 6 documented species across the lake's records. The lake lacks a documented public access point, so visitor use is limited. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.