St. Louis Bay Lake

On the scoring rubric St. Louis Bay Lake grades a D: clarity at 1.3 ft and 71 µg/L of phosphorus keep it in the lower bracket for Douglas County. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. 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 52 graded lakes of Douglas County, St. Louis Bay Lake sits at rank 49, near the bottom of the county list.

St. Louis Bay Lake has at least one documented invasive species (Rainbow Smelt), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. The state fisheries records do not list documented species for St. Louis Bay Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. A documented public access point at St. Louis Bay Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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.