Big Swan Lake

Big Swan Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade.

Mesotrophic conditions dominate at Big Swan Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. Big Swan Lake reaches 45 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. The lake's 947 acres and 7.8 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 Todd County's 17 graded lakes, Big Swan Lake ranks 10 — below the local median, though not at the bottom.

No invasive species are currently listed at Big Swan Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye among the lake's 16 documented species — a notable draw for Minnesota anglers. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been logged at Big Swan Lake more than two dozen times, putting the median around Apr 13 — a useful baseline for tracking climate trends. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.