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. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

A TSI near 46 places Big Swan Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. A maximum depth of 45 ft puts Big Swan Lake in the middle of Minnesota's depth distribution. At 947 acres, Big Swan Lake fits the Minnesota median for monitored lakes, with 7.8 miles of shoreline. Big Swan Lake sits at rank 10 of 17 in Todd County, in the lower half of the local distribution.

Big Swan Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. The fishery includes walleye alongside the lake's other 16 documented species — a notable draw for Minnesota anglers. A documented public access point at Big Swan Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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.