Rat Lake

On the scoring rubric Rat Lake grades a D: clarity at 3.3 ft and 62 µg/L of phosphorus keep it in the lower bracket for Itasca County. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. The lake bottoms out at 20 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. The lake is compact at 96 acres, with 1.9 miles of shoreline and little volume to buffer nutrient inputs. Rat Lake ranks 138 of 141 in Itasca County — at the lower end of the locally monitored distribution.

Rat 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 Rat Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. No formal public access is documented at Rat Lake — most use is by shoreline residents and their guests. 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.