Grignon Lake

Grignon Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Wisconsin norms.

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. Grignon Lake ranks 51 of 62 in Oconto County — at the lower end of the locally monitored distribution.

Grignon Lake has no invasive species recorded in Wisconsin state databases as of 2021, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Grignon 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.