Okauchee Lake

On the LakeGrade rubric, Okauchee Lake pulls an A: clarity at 12.0 ft and 17 µg/L of phosphorus put it in the top bracket for Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI near 43 places Okauchee Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. The lake's 90 ft maximum depth is in the upper tier for Wisconsin — deep enough for cold-water fish to find refuge in summer. Okauchee Lake covers 1,210 acres alongside partial shoreline records, large enough that conditions can vary meaningfully between bays. Okauchee Lake ranks 19 of 45 in Waukesha County — solidly in the upper half of the local distribution.

Zebra mussels have been documented at Okauchee Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. Walleye are documented at Okauchee Lake, one of 6 fish species on record for the lake. Public access is available — the lake is on the Wisconsin DNR public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.