Flambeau Lake

Flambeau 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.

The lake's low TSI puts it in oligotrophic territory — the cleanest of the four trophic classes, but also the most vulnerable to nutrient-driven shifts. Flambeau Lake is unusually deep for Wisconsin at 78 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. Flambeau Lake covers 1,166 acres alongside partial shoreline records, large enough that conditions can vary meaningfully between bays. Among the 202 graded lakes in Vilas County, Flambeau Lake sits at rank 77, above the county median.

An invasive species record — Purple Loosestrife — has been logged at Flambeau Lake; Wisconsin DNR maintains the official infested-waters list. The fishery includes walleye alongside the lake's other 6 documented species — a notable draw for Wisconsin anglers. 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.