Rush Lake

On the LakeGrade rubric, Rush Lake pulls an A: clarity at 18.0 ft and 12 µg/L of phosphorus put it in the top bracket for Minnesota. 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 value of 38 puts Rush Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. At 105 ft of maximum depth, Rush Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. Rush Lake covers 858 acres alongside 14.8 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Among the 120 graded lakes in Crow Wing County, Rush Lake ranks 25 — in the top quartile locally.

Zebra mussel presence at Rush Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. Walleye are documented at Rush Lake, one of 21 fish species on record for the lake. The lake lacks a documented public access point, so visitor use is limited. Ice-out has been recorded 8 times at Rush Lake, with a median around Apr 19. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.