Karl Lake

Karl 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 Karl Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. At 70 ft of maximum depth, Karl Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. Karl Lake covers 121 acres alongside 5.4 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Karl Lake sits at rank 85 of 128 in Cook County, in the lower half of the local distribution.

Karl Lake has no invasive species recorded in Minnesota state databases as of 2022, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Karl Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. 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.