Otter Lake

Otter Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Otter Tail County. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI value of 35 puts Otter Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake's 64 ft maximum depth is in the upper tier for Minnesota — deep enough for cold-water fish to find refuge in summer. The lake is compact at 77 acres, with 2.1 miles of shoreline and little volume to buffer nutrient inputs. Within Otter Tail County's 97 graded waters, Otter Lake sits at rank 3, near the top of the local distribution.

Otter Lake has no invasive species recorded in Minnesota state databases as of 2020, though prevention practices still apply at all access points. Bass fishing is part of the appeal: the species list runs to 7, anchored by largemouth and/or smallmouth bass. No formal public access is documented at Otter 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.