Mallard Lake

Mallard Lake pulls a D on the LakeGrade rubric — phosphorus loading and limited clarity hold it below the Wisconsin average. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. Mallard Lake is a shallow lake at 10 ft maximum depth, which means it warms quickly, mixes constantly, and amplifies nutrient inputs. The lake is compact at 16 acres, with partial shoreline records and little volume to buffer nutrient inputs. Mallard Lake ranks 14 of 14 in Milwaukee County — at the lower end of the locally monitored distribution.

Eurasian watermilfoil has been documented at Mallard Lake, requiring shoreline management to keep dense mats from crowding native vegetation. 1 fish species are documented at Mallard Lake, a mixed warm-water community typical for Wisconsin lakes of this size. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.