Plainfield Lake

The LakeGrade rubric puts Plainfield Lake at a C: clarity at 6.8 ft, phosphorus readings still being added, and a TSI of 50 signal an intermediate trophic state. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

The lake sits in the mesotrophic zone — the band where most well-managed Wisconsin lakes fall. At only 12 ft deep, Plainfield Lake is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. Plainfield Lake is small — 29 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Within the 32 graded lakes of Waushara County, Plainfield Lake sits at rank 29, near the bottom of the county list.

Plainfield Lake has at least one documented invasive species (Banded Mystery Snail), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. The lake's fish records list 1 species — a varied community without one dominant gamefish. Public access is available — the lake is on the Wisconsin DNR public-access list. 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.