Johnson Lake

Johnson Lake grades an F: water clarity, phosphorus, and chlorophyll-a all rate poorly, placing it among the most stressed lakes monitored in Minnesota. 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.

At a TSI of 70, Johnson Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. Johnson Lake reaches 18 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. Johnson Lake covers 2,730 acres alongside 14.3 miles of shoreline, large enough that conditions can vary meaningfully between bays. Johnson Lake ranks 28 of 35 in Kandiyohi County — at the lower end of the locally monitored distribution.

Johnson Lake has no invasive species recorded in Minnesota state databases as of 2022, 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 Johnson 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.