Upper Eau Claire Lake

Upper Eau Claire Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Trophically, Upper Eau Claire Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. The lake's 92 ft maximum depth is in the upper tier for Wisconsin — deep enough for cold-water fish to find refuge in summer. With 1,024 acres of surface and partial shoreline records, Upper Eau Claire Lake is a large water by Wisconsin standards — recreational pressure is spread across a long shoreline. Upper Eau Claire Lake ranks 2 of 55 in Bayfield County, putting it in the upper tier of locally monitored lakes.

Upper Eau Claire Lake has at least one documented invasive species (Chinese Mystery Snail), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. Walleye are documented at Upper Eau Claire Lake, one of 6 fish species on record for the lake. 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.