Buchanan Lake

Buchanan Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. The lake's weakest score is on Secchi depth — the water looks more turbid than its phosphorus number alone would predict.

At a TSI of 51, Buchanan Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. A maximum depth of 42 ft puts Buchanan Lake in the middle of Minnesota's depth distribution. The lake's 964 acres and 7.9 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within the 97 graded lakes of Otter Tail County, Buchanan Lake sits at rank 82, near the bottom of the county list.

Zebra mussels have been documented at Buchanan Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. The fishery is bass-led, with 8 documented species across the lake's records. A documented public access point at Buchanan 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.