Carrol Lake

Carrol Lake earns an F: phosphorus readings still being added and clarity at 2.5 ft signal heavy nutrient loading from the surrounding watershed. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

At a TSI of 64, Carrol Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. The lake bottoms out at 27 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. At 330 acres, Carrol Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Within the 134 graded lakes of Oneida County, Carrol Lake sits at rank 131, near the bottom of the county list.

Eurasian watermilfoil has been documented at Carrol Lake, requiring shoreline management to keep dense mats from crowding native vegetation. Walleye are documented at Carrol Lake, one of 5 fish species on record for the lake. 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.