Sandstone Flowage Lake

On the scoring rubric Sandstone Flowage Lake grades a D: clarity at 5.5 ft and phosphorus readings still being added keep it in the lower bracket for Marinette County. 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.

At a TSI of 53, Sandstone Flowage Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. 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. Sandstone Flowage Lake ranks 21 of 21 in Marinette County — at the lower end of the locally monitored distribution.

Sandstone Flowage Lake has no invasive species recorded in Wisconsin state databases as of 2025, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Sandstone Flowage 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.