Byllesby Lake

Byllesby Lake earns an F: 220 µg/L of phosphorus and clarity at 3.0 ft signal heavy nutrient loading from the surrounding watershed. 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.

The hypereutrophic status — TSI 72 — reflects sustained heavy nutrient loading from the surrounding watershed and frequent algal pressure. At 50 ft of maximum depth, Byllesby Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. Byllesby Lake covers 1,368 acres alongside 13.9 miles of shoreline, large enough that conditions can vary meaningfully between bays. Byllesby Lake ranks 35 of 36 in Dakota County — at the lower end of the locally monitored distribution.

Byllesby Lake is on the Minnesota infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. Walleye are documented at Byllesby Lake, one of 19 fish species on record for the lake. A documented public access point at Byllesby Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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.