Deep Lake

On the scoring rubric Deep Lake grades a D: clarity at 3.9 ft and 72 µg/L of phosphorus keep it in the lower bracket for Ramsey 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. Deep Lake is a shallow lake at 11 ft maximum depth, which means it warms quickly, mixes constantly, and amplifies nutrient inputs. The lake is compact at 72 acres, with 1.7 miles of shoreline and little volume to buffer nutrient inputs. Within Ramsey County's 49 graded lakes, Deep Lake ranks 36 — below the local median, though not at the bottom.

Deep Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. Deep Lake's fishery is anchored by muskellunge, with 19 documented species in total — a destination water for muskie anglers. No formal public access is documented at Deep 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.