Alder Lake

Alder 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. A maximum depth of 30 ft puts Alder Lake in the middle of Wisconsin's depth distribution. At 264 acres, Alder Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Alder Lake ranks 100 of 202 in Vilas County — solidly in the upper half of the local distribution.

An invasive species record — Banded Mystery Snail — has been logged at Alder Lake; Wisconsin DNR maintains the official infested-waters list. Walleye are documented at Alder 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. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.