Crescent Lake

On the LakeGrade rubric, Crescent Lake pulls an A: clarity at 26.2 ft and 17 µg/L of phosphorus put it in the top bracket for Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

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. The lake bottoms out at 43 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. The lake is compact at 15 acres, with partial shoreline records and little volume to buffer nutrient inputs. Within Polk County's 77 graded waters, Crescent Lake sits at rank 7, near the top of the local distribution.

No invasive species are currently listed at Crescent Lake — the lake remains off the Wisconsin infested-waters roster. 2 fish species are documented at Crescent Lake, a mixed warm-water community typical for Wisconsin lakes of this size. Public access is available — the lake is on the Wisconsin DNR public-access list. 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.