Duck Lake

Duck Lake earns a D — measurements through 2022 show persistent nutrient pressure that limits clarity through the summer. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

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. A maximum depth of 30 ft puts Duck Lake in the middle of Wisconsin's depth distribution. The lake is compact at 30 acres, with partial shoreline records and little volume to buffer nutrient inputs. Within the 55 graded lakes of Bayfield County, Duck Lake sits at rank 55, near the bottom of the county list.

Duck Lake has no invasive species recorded in Wisconsin state databases as of 2022, though prevention practices still apply at all access points. 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.