Clay Lake

Clay Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Wisconsin norms.

At a TSI of 52, Clay Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. A maximum depth of 45 ft puts Clay Lake in the middle of Wisconsin's depth distribution. At 28 acres, Clay Lake sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Within the 52 graded lakes of Bayfield County, Clay Lake sits at rank 44, near the bottom of the county list.

Clay Lake has no invasive species recorded in Wisconsin state databases as of 2023, 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.