Sisseton Lake

Sisseton Lake grades an F: every scored parameter (clarity, phosphorus, and chlorophyll-a) rates poorly, placing it among the most stressed lakes monitored in Minnesota. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. A maximum depth of 19 ft puts Sisseton Lake in the middle of Minnesota's depth distribution. Sisseton Lake covers 138 acres alongside 2.8 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within Martin County's 7 graded lakes, Sisseton Lake ranks 4 — below the local median, though not at the bottom.

No invasive species are currently listed at Sisseton Lake — the lake remains off the Minnesota infested-waters roster. Muskie are on the species list at Sisseton Lake, among the lake's 20 documented fish. Public access is available — the lake is on the Minnesota PCA public-access list. The lake has a long ice-out record — 110 observations on file, with a median ice-out around Apr 2. Multiple sampling years from Minnesota PCA volunteers and partner agencies back the grade, so the letter should hold steady absent a major watershed shift.