Ada Lake

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

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. At only 13 ft deep, Ada Lake is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. Ada Lake is small — 23 acres alongside 1.6 miles of shoreline — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Within the 128 graded lakes of Cook County, Ada Lake sits at rank 99, near the bottom of the county list.

Ada Lake has no invasive species recorded in Minnesota state databases as of 2022, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Ada Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. No formal public access is documented at Ada Lake — most use is by shoreline residents and their guests. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.