Flowage Lake

The LakeGrade rubric puts Flowage Lake at a C: clarity at 8.5 ft, phosphorus readings still being added, and a TSI of 46 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.

Mesotrophic conditions dominate at Flowage Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake bottoms out at 15 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. The lake's 112 acres and 3.1 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Flowage Lake sits at rank 104 of 187 in St. Louis County, in the lower half of the local distribution.

No invasive species are currently listed at Flowage Lake — the lake remains off the Minnesota infested-waters roster. Bass fishing is part of the appeal: the species list runs to 7, anchored by largemouth and/or smallmouth bass. The lake lacks a documented public access point, so visitor use is limited. The lake has a long ice-out record — 25 observations on file, with a median ice-out around Apr 22. 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.