Franklin Lake

On the LakeGrade rubric, Franklin Lake pulls an A: clarity at 13.1 ft and 17 µg/L of phosphorus put it in the top bracket for 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.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. The lake bottoms out at 48 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Franklin Lake covers 1,088 acres alongside 12.7 miles of shoreline, large enough that conditions can vary meaningfully between bays. Among the 97 graded lakes in Otter Tail County, Franklin Lake sits at rank 40, above the county median.

Zebra mussels have been documented at Franklin Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. Walleye are documented at Franklin Lake, one of 18 fish species on record for the lake. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been recorded 12 times at Franklin Lake, with a median around Apr 19. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.