South Bay Lake

South Bay Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Forest County. 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 46 ft puts South Bay Lake in the middle of Wisconsin's depth distribution. South Bay Lake covers 839 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. South Bay Lake ranks 10 of 35 in Forest County — solidly in the upper half of the local distribution.

South Bay Lake has at least one documented invasive species (Banded Mystery Snail), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. Walleye are documented at South Bay Lake, one of 5 fish species on record for the lake. A documented public access point at South Bay Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.