Manomin Lake

Manomin Lake earns an F: phosphorus readings still being added and clarity at 2.0 ft signal heavy nutrient loading from the surrounding watershed. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

At a TSI of 67, Manomin Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. A maximum depth of 18 ft puts Manomin Lake in the middle of Minnesota's depth distribution. At 409 acres, Manomin Lake fits the Minnesota median for monitored lakes, with 6.7 miles of shoreline. Within the 142 graded lakes of Lake County, Manomin Lake sits at rank 142, near the bottom of the county list.

No invasive species are currently listed at Manomin Lake — the lake remains off the Minnesota infested-waters roster. The fishery is bass-led, with 5 documented species across the lake's records. No formal public access is documented at Manomin Lake — most use is by shoreline residents and their guests. 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.