Turtle Lake

Turtle Lake earns a D — measurements through 2021 show persistent nutrient pressure that limits clarity through the summer.

A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. At only 7 ft deep, Turtle Lake is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. Turtle Lake is small — 25 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Turtle Lake ranks 51 of 52 in Bayfield County — at the lower end of the locally monitored distribution.

No invasive species are currently listed at Turtle Lake — the lake remains off the Wisconsin infested-waters roster. Bass fishing is part of the appeal: the species list runs to 2, anchored by largemouth and/or smallmouth bass. 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.