Upper Mississippi River Restoration Project Big Lake, Pool 4, Wisconsin

U.S. Army Corps of Engineers, St. Paul District
Published April 4, 2022
Updated: Sept. 25, 2023

As with the much of the upper Mississippi River, sedimentation of backwater areas is an ongoing issue. The project area is greatly influenced by the input of sand from the Chippewa River that enters Pool 4 at about river mile 764. Other potential sources of sand are the historic channel maintenance dredging side-cast islands and the four active temporary placement sites within the study area. Big Lake has lost much of its island complex and bottomland forest to wind and wave erosion. The barrier islands between the lake and Catfish Slough have been degraded and/or eliminated over the past several years.


The project area consists of open backwater, meandered side channels, main channel border, and island formations in the Mississippi River in lower Pool 4. The site is in the Upper Mississippi River National Wildlife and Fish Refuge near Alma, Wisconsin.


The proposed project goal is to maintain, enhance, and create habitat suitable for native and desirable, aquatic and terrestrial plants and animals. Sedimentation of the backwaters is an ongoing issue in this study area. Big Lake has lost much of its island complex and forest to wind and wave erosion.

The project seeks to protect, enhance, restore, or create naturally regenerating, resilient, and diverse bottomland forest that will benefit migratory and resident birds and other species. The project seeks to protect, enhance, restore, or create backwater and flowing channel habitats that provide flow conditions and sediment dynamics that will benefit native fish (including migratory species) and mussel populations. Maintain or increase quantity and diversity of submerged, emergent, and rooted floating leaved vegetation. The construction, enhancement, and protection of island features could provide for opportunistic use of main channel dredge material placement.


Project planning began in the fiscal year 2022. The Corps will plan and design the project as part of a cooperative effort with the U.S. Fish and Wildlife Service (USFWS), the Wisconsin and Minnesota Departments of Natural Resources and local interests.

A public meeting was held in Wabasha, Minnesota, in 2022. The Corps identified a Tentatively Selected Plan in July 2023 and will be releasing the draft report for public review in fall 2023. The feasibility report will be completed in 2024.


Congress originally authorized the UMRR Program in Section 1103 of the 1986 Water Resources Development Act (WRDA) (Public Law 99‒662), codified at 33 U.S.C. § 652. Section 307 of WRDA 2020 (Public Law 116‒260) increased the authorized program funding to a combined $55 million annually.


Project design and construction costs will be 100% federally funded because the project is located on lands managed as a national wildlife refuge. Operation and maintenance costs are 100% federal and a responsibility of the USFWS.

Federal Funds Allocated to Date        $1,039,000