Oneka Lake

On the scoring rubric Oneka Lake grades a D: clarity at 4.4 ft and phosphorus readings still being added keep it in the lower bracket for Washington County. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

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. Within the 31 graded lakes of Washington County, Oneka Lake sits at rank 30, near the bottom of the county list.

No invasive species are currently listed at Oneka Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Oneka Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. A documented public access point at Oneka Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.