Big Dummy Lake

On the LakeGrade rubric, Big Dummy Lake pulls an A: clarity at 39.4 ft and 16 µg/L of phosphorus put it in the top bracket for Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI value of 34 puts Big Dummy Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. Big Dummy Lake is unusually deep for Wisconsin at 54 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. Big Dummy Lake covers 114 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Among the 38 graded lakes in Barron County, Big Dummy Lake ranks 9 — in the top quartile locally.

An invasive species record — Chinese Mystery Snail — has been logged at Big Dummy Lake; Wisconsin DNR maintains the official infested-waters list. Walleye are documented at Big Dummy Lake, one of 4 fish species on record for the lake. Public access is available — the lake is on the Wisconsin DNR public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.