Black Brook Flowage Lake

On the LakeGrade scale Black Brook Flowage Lake grades a B, with clarity at 20.5 ft and 47 µg/L of phosphorus placing it above the Wisconsin median. Of the three parameters, phosphorus is the worst — at 47 µg/L of phosphorus, it keeps the lake susceptible to algal blooms in warm years.

Mesotrophic conditions dominate at Black Brook Flowage Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. 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. Black Brook Flowage Lake sits at rank 50 of 77 in Polk County, in the lower half of the local distribution.

Black Brook Flowage Lake has no invasive species recorded in Wisconsin state databases as of 2020, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Black Brook Flowage 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.