Slate Lake

The LakeGrade rubric puts Slate Lake at a C: clarity at 4.4 ft, 22 µg/L of phosphorus, and a TSI of 52 signal an intermediate trophic state. Secchi readings are the weakest of the three parameters, suggesting suspended sediment or algal biomass dominates the optical signal.

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. At only 7 ft deep, Slate Lake is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. Slate Lake covers 293 acres alongside 8.1 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Slate Lake ranks 132 of 159 in Lake County — at the lower end of the locally monitored distribution.

No invasive species are currently listed at Slate Lake — the lake remains off the Minnesota infested-waters roster. Walleye are documented at Slate Lake, one of 8 fish species on record for the lake. No formal public access is documented at Slate 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.