Unknown Lake

On the scoring rubric Unknown Lake grades a D: clarity at 7.9 ft and 136 µg/L of phosphorus keep it in the lower bracket for Grant County. Of the three parameters, phosphorus is the worst — at 136 µg/L of phosphorus, it keeps the lake susceptible to algal blooms in warm years.

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. 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 the 3 graded lakes of Grant County, Unknown Lake sits at rank 3, near the bottom of the county list.

No invasive species are currently listed at Unknown Lake — the lake remains off the Wisconsin infested-waters roster. The state fisheries records do not list documented species for Unknown 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.