Clear Lake

Clear Lake grades an F: water clarity, phosphorus, and chlorophyll-a all rate poorly, placing it among the most stressed lakes monitored in Minnesota. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Hypereutrophic conditions mean the lake is operating at the upper end of the productivity scale, with all the bloom risk that implies. At only 8 ft deep, Clear Lake is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. The lake's 252 acres and 3.0 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Clear Lake sits at rank 4 of 7 in Brown County, in the lower half of the local distribution.

Clear Lake has no invasive species recorded in Minnesota state databases as of 2023, though prevention practices still apply at all access points. Walleye are documented at Clear Lake, one of 12 fish species on record for the lake. A documented public access point at Clear Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is supported by multiple sampling years from Minnesota PCA volunteers and partner agencies, giving the letter a reasonably stable foundation.