Turtle Lake

The LakeGrade rubric puts Turtle Lake at a C: clarity at 3.6 ft, 57 µg/L of phosphorus, and a TSI of 60 signal an intermediate trophic state. 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.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. At only 12 ft deep, Turtle Lake is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. Turtle Lake covers 525 acres alongside 6.7 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Turtle Lake sits at rank 11 of 20 in Polk County, in the lower half of the local distribution.

No invasive species are currently listed at Turtle Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Turtle Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. Public access is available — the lake is on the Minnesota PCA 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.