Little Carnelian Lake

On the LakeGrade rubric, Little Carnelian Lake pulls an A: clarity at 21.0 ft and phosphorus readings still being added 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.

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. At 68 ft of maximum depth, Little Carnelian Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. The lake's 137 acres and 2.6 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Among the 31 graded lakes in Washington County, Little Carnelian Lake ranks 4 — in the top quartile locally.

Zebra mussel presence at Little Carnelian Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. Bass fishing is part of the appeal: the species list runs to 10, anchored by largemouth and/or smallmouth bass. The lake lacks a documented public access point, so visitor use is limited. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.