Island Lake

On the LakeGrade rubric, Island Lake pulls an A: clarity at 15.3 ft and 12 µg/L of phosphorus put it in the top bracket for Minnesota. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

The lake's low TSI puts it in oligotrophic territory — the cleanest of the four trophic classes, but also the most vulnerable to nutrient-driven shifts. Island Lake is unusually deep for Minnesota at 76 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake's 232 acres and 5.2 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within Crow Wing County's 120 graded waters, Island Lake sits at rank 14, near the top of the local distribution.

Zebra mussels have been documented at Island Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. The fishery includes walleye alongside the lake's other 19 documented species — a notable draw for Minnesota anglers. No formal public access is documented at Island 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.