Fannie Lake

The LakeGrade rubric puts Fannie Lake at a C: clarity at 7.0 ft, 37 µg/L of phosphorus, and a TSI of 52 signal an intermediate trophic state. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. Fannie Lake reaches 33 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 360 acres, Fannie Lake fits the Minnesota median for monitored lakes, with 6.0 miles of shoreline. Fannie Lake ranks 7 of 19 in Isanti County — solidly in the upper half of the local distribution.

Eurasian watermilfoil is established at Fannie Lake, which can dampen recreational access and pressure the native plant community. The fishery includes walleye alongside the lake's other 13 documented species — a notable draw for Minnesota anglers. A documented public access point at Fannie Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Multiple sampling years from Minnesota PCA volunteers and partner agencies back the grade, so the letter should hold steady absent a major watershed shift.