Turtle Lake

Turtle Lake grades an F: water clarity, phosphorus, and chlorophyll-a all rate poorly, placing it among the most stressed lakes monitored in Minnesota. 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 61, Turtle Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. A maximum depth of 28 ft puts Turtle Lake in the middle of Minnesota's depth distribution. Turtle Lake covers 450 acres alongside 3.6 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within the 49 graded lakes of Ramsey County, Turtle Lake sits at rank 48, near the bottom of the county list.

Zebra mussels have been documented at Turtle Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. Walleye are documented at Turtle Lake, one of 15 fish species on record for the lake. A documented public access point at Turtle Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The lake has a partial ice record — 13 observed ice-outs, centered near Mar 29. 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.