Prairie Lake

Prairie Lake pulls a D on the LakeGrade rubric — phosphorus loading and limited clarity hold it below the Minnesota average. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. A maximum depth of 47 ft puts Prairie Lake in the middle of Minnesota's depth distribution. The lake's 794 acres and 8.2 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Prairie Lake ranks 158 of 187 in St. Louis County — at the lower end of the locally monitored distribution.

No invasive species are currently listed at Prairie Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye alongside the lake's other 15 documented species — a notable draw for Minnesota anglers. A documented public access point at Prairie Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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.