Oconomowoc Lake Site

On the LakeGrade rubric, Oconomowoc Lake Site pulls an A: clarity at 13.0 ft and 14 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 41 places Oconomowoc Lake Site in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. Oconomowoc Lake Site is unusually deep for Wisconsin at 60 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake's 818 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. Oconomowoc Lake Site ranks 15 of 45 in Waukesha County — solidly in the upper half of the local distribution.

Zebra mussels have been documented at Oconomowoc Lake Site, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. Walleye are documented at Oconomowoc Lake Site, one of 5 fish species on record for the lake. 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.