Saint Johns Lake

Saint Johns Lake grades an F: water clarity, phosphorus, and chlorophyll-a all rate poorly, placing it among the most stressed lakes monitored in Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Hypereutrophic conditions mean the lake is operating at the upper end of the productivity scale, with all the bloom risk that implies. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Within Kandiyohi County's 35 graded lakes, Saint Johns Lake ranks 25 — below the local median, though not at the bottom.

No invasive species are currently listed at Saint Johns Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Saint Johns Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. No formal public access is documented at Saint Johns Lake — most use is by shoreline residents and their guests. The lake has a partial ice record — 8 observed ice-outs, centered near Apr 7. 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.