Birch Lake

On the LakeGrade rubric, Birch Lake pulls an A: clarity at 15.0 ft and phosphorus readings still being added put it in the top bracket for Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Trophically, Birch Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. Birch Lake reaches 34 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 836 acres, Birch Lake fits the Minnesota median for monitored lakes, with 27.8 miles of shoreline. Among the 5 graded lakes in Unknown County, Birch Lake ranks 1 — in the top quartile locally.

No invasive species are currently listed at Birch Lake — the lake remains off the Minnesota infested-waters roster. Walleye are documented at Birch Lake, one of 10 fish species on record for the lake. No formal public access is documented at Birch 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.