Portage Lake

The LakeGrade rubric puts Portage Lake at a C: clarity at 5.7 ft, 28 µg/L of phosphorus, and a TSI of 52 signal an intermediate trophic state. The lake's weakest score is on Secchi depth — the water looks more turbid than its phosphorus number alone would predict.

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 17 ft puts Portage Lake in the middle of Minnesota's depth distribution. At 429 acres, Portage Lake fits the Minnesota median for monitored lakes, with 5.3 miles of shoreline. Portage Lake ranks 71 of 77 in Hubbard County — at the lower end of the locally monitored distribution.

No invasive species are currently listed at Portage Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye alongside the lake's other 12 documented species — a notable draw for Minnesota anglers. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been logged at Portage Lake more than two dozen times, putting the median around Apr 18 — a useful baseline for tracking climate trends. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.