Lac la Belle Lake

On the LakeGrade scale Lac la Belle Lake grades a B, with clarity at 10.1 ft and phosphorus readings still being added placing it above the Wisconsin median. 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.

A TSI near 44 places Lac la Belle Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. 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 48 graded lakes of Waukesha County, Lac la Belle Lake sits at rank 37, 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.