Eagle Spring Lake

On the LakeGrade scale Eagle Spring Lake grades a B, with clarity at 4.3 ft and 18 µg/L of phosphorus placing it above the Wisconsin median. Secchi readings are the weakest of the three parameters, suggesting suspended sediment or algal biomass dominates the optical signal.

At a TSI of 51, Eagle Spring Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. Eagle Spring Lake is a shallow lake at 8 ft maximum depth, which means it warms quickly, mixes constantly, and amplifies nutrient inputs. The lake's 279 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. Eagle Spring Lake sits at rank 33 of 45 in Waukesha County, in the lower half of the local distribution.

Zebra mussels have been documented at Eagle Spring Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. Bass fishing is part of the appeal: the species list runs to 3, anchored by largemouth and/or smallmouth bass. 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.