Lac la Belle Lake

On the scoring rubric Lac la Belle Lake grades a D: clarity at 5.5 ft and phosphorus readings still being added keep it in the lower bracket for Waukesha County. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

At a TSI of 53, Lac la Belle Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. Lac la Belle Lake reaches 45 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. With 1,154 acres of surface and partial shoreline records, Lac la Belle Lake is a large water by Wisconsin standards — recreational pressure is spread across a long shoreline. Within the 45 graded lakes of Waukesha County, Lac la Belle Lake sits at rank 42, near the bottom of the county list.

Zebra mussels have been documented at Lac la Belle Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. Walleye are documented at Lac la Belle 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.