Cosgrove Lake

The LakeGrade rubric puts Cosgrove Lake at a C: clarity at 9.4 ft, phosphorus readings still being added, and a TSI of 45 signal an intermediate trophic state. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

Mesotrophic conditions dominate at Cosgrove 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. Cosgrove Lake ranks 33 of 39 in Florence County — at the lower end of the locally monitored distribution.

No invasive species are currently listed at Cosgrove Lake — the lake remains off the Wisconsin infested-waters roster. The state fisheries records do not list documented species for Cosgrove Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.