Gilbert Lake

Gilbert Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI value of 39 puts Gilbert Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake bottoms out at 45 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Gilbert Lake covers 357 acres alongside 7.1 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Gilbert Lake ranks 60 of 120 in Crow Wing County — solidly in the upper half of the local distribution.

Zebra mussels have been documented at Gilbert Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. The fishery is bass-led, with 9 documented species across the lake's records. Public access is available — the lake is on the Minnesota PCA public-access list. The lake has a long ice-out record — 47 observations on file, with a median ice-out around Apr 18. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.