Moon Lake

Moon Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

At a TSI of 57, Moon Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. Moon Lake is a shallow lake at 5 ft maximum depth, which means it warms quickly, mixes constantly, and amplifies nutrient inputs. At 74 acres, Moon Lake sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Within the 38 graded lakes of Barron County, Moon Lake sits at rank 30, near the bottom of the county list.

An invasive species record — Chinese Mystery Snail — has been logged at Moon Lake; Wisconsin DNR maintains the official infested-waters list. The lake's fish records list 2 species — a varied community without one dominant gamefish. 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.