Mirror Lake

Mirror Lake comes in at a B on the grading rubric — a respectable showing for a Wisconsin lake of its size and depth. Of the three parameters, phosphorus is the worst — at 65 µg/L of phosphorus, it keeps the lake susceptible to algal blooms in warm years.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Within Sauk County's 11 graded lakes, Mirror Lake ranks 6 — below the local median, though not at the bottom.

No invasive species are currently listed at Mirror Lake — the lake remains off the Wisconsin infested-waters roster. The state fisheries records do not list documented species for Mirror Lake, which usually reflects a lack of formal fisheries survey work rather than an empty 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.