Rhinelander Flowage Lake

Rhinelander Flowage Lake earns a D — measurements through 2025 show persistent nutrient pressure that limits clarity through the summer. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

At a TSI of 57, Rhinelander Flowage Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. Rhinelander Flowage Lake is a shallow lake at 10 ft maximum depth, which means it warms quickly, mixes constantly, and amplifies nutrient inputs. With 1,372 acres of surface and partial shoreline records, Rhinelander Flowage Lake is a large water by Wisconsin standards — recreational pressure is spread across a long shoreline. Within the 134 graded lakes of Oneida County, Rhinelander Flowage Lake sits at rank 115, near the bottom of the county list.

Rhinelander Flowage Lake has at least one documented invasive species (Chinese Mystery Snail), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. Walleye are documented at Rhinelander Flowage Lake, one of 6 fish species on record for the lake. A documented public access point at Rhinelander Flowage 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.