Portage Lake is a shallow, medium-sized lake located three miles northwest of Park Rapids in west central Hubbard County. The lake has a fair amount of development on the northern and southern shores. U.S. Highway 71 is next to the lake on the eastern shore. It has a moderate-sized watershed relative to its surface area (16:1 lake to watershed ratio). While forest is the predominant land use in the watershed, the percentage of agricultural uses (pasture and cultivated) is relatively high for a lake in the Northern Lakes and Forests ecoregion. The lake was assessed as non-supporting of aquatic recreational uses because of elevated nutrients and was placed on Minnesota’s 303(d) “Impaired Waters” list in 2006.
Curlyleaf Pondweed has become increasingly abundant in the lake. On the other hand, Muskgrass, a native plant which promotes clear water, is also increasing. Muskgrass also provides habitat for fish species. Historically, Wild Rice was reported in the lake.
Portage Lake infrequently experiences partial winterkills due to low levels of dissolved oxygen. Those events can dramatically affect species’ abundance and subsequent growth and condition. The fish community of the lake includes Walleye, Northern Pike, Yellow Perch, Black Crappie, Bluegill, and Largemouth Bass.
Portage Lake was selected for the Sentinel Lakes program because it represents a shallow, eutrophic lake in the Northern Lakes and Forests ecoregion.