Bear Trap Lake

Bear Trap Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Polk County. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Trophically, Bear Trap Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. A maximum depth of 25 ft puts Bear Trap Lake in the middle of Wisconsin's depth distribution. The lake's 247 acres and partial shoreline records put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Among the 77 graded lakes in Polk County, Bear Trap Lake sits at rank 35, above the county median.

Zebra mussel presence at Bear Trap Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. The fishery includes walleye alongside the lake's other 5 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.