Sewell Lake

Sewell Lake pulls a D on the LakeGrade rubric — phosphorus loading and limited clarity hold it below the Minnesota average. 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. Sewell Lake is unusually deep for Minnesota at 52 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake's 369 acres and 5.6 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Sewell Lake ranks 92 of 97 in Otter Tail County — at the lower end of the locally monitored distribution.

Sewell Lake has no invasive species recorded in Minnesota state databases as of 2023, though prevention practices still apply at all access points. Walleye are documented at Sewell Lake, one of 13 fish species on record for the lake. A documented public access point at Sewell Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.