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.

At a TSI of 67, Manomin Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. Manomin Lake reaches 18 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. The lake's 409 acres and 6.7 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Manomin Lake ranks 142 of 142 in Lake County — at the lower end of the locally monitored distribution.

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. The lake lacks a documented public access point, so visitor use is limited. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.