Beneficial Uses of Dredged Sediment

US Army Corps of Engineers

LAKE PEPIN RESTORATION

Aerial view of a river restoration project under construction, showing newly formed sandy and rock-lined islands and channels curving through the water, with wooded bluffs in the distance.
Upper Pool 4 project construction, October 2025. Source: U.S. Army Corps of Engineers, St. Paul District.
  • Title: Lake Pepin Restoration
  • State: Wisconsin
  • Project type: USACE
  • Greater Beneficial Use Area: Upper Mississippi River
  • Focus Area approximate center coordinates: 44.609327, -92.612103
  • Nearest Federal Navigation Project: Mississippi River Navigation Channel
  • Owner: USACE St. Paul District
  • Beneficial Use Categories: Aquatic Habitats, Wetland Habitats
  • Dredge type: N/A
  • Status: Ongoing
  • Keywords: Habitat Restoration, Upper Pool 4, Mississippi River

Description:

Located between river miles 780 and 792, Lake Pepin is situated in Upper Pool 4 of the Mississippi River. A restoration effort was planned in 2021 to protect the backwater areas adjacent to the main river channel, near the community of Bay City, Wisconsin. This project spans a significant portion of the head of the lake, introducing large-scale geographic features designed to reshape the local hydrology (USACE 2026a).

The Lake Pepin area is an invaluable ecological asset, providing vital sanctuary for backwater waterfowl, shorebirds, aquatic mammals, amphibians, and a diverse riverine fishery. It also offers extensive recreational and economic benefits to local communities. However, severe sedimentation and sediment resuspension over the decades have drastically reduced water depth in the backwater lakes and isolated wetlands above Lake Pepin (USACE 2026a). This shallowing effect has smothered aquatic vegetation, degraded overall habitat quality, and significantly reduced the abundance of critical invertebrates, fish, and wildlife, requiring urgent intervention to prevent the lake from prematurely infilling.

Efforts to restore the area began when the Lake Pepin Legacy Alliance requested a feasibility study in December 2015 (USACE 2026a). The project began in 2017 and was completed in August 2020, leading to a project partnership agreement to restore the backwater area in 2021. This restoration effort began in August 2023 and is scheduled for completion in October 2026. The comprehensive restoration plan involves constructing three peninsulas, two deep-water overwintering areas, three wetland areas, shoreline protection, and a water-level management dike. These features aim to shelter the backwaters, reduce turbidity, and allow vegetation to flourish. The total cost for this collaborative project is $21,953,470, which is cost-shared between federal funds and the Wisconsin Department of Natural Resources (USACE 2026a).

To build these restorative features, the project relies on the beneficial use of dredged material generated from USACE’s routine maintenance of the 9-foot navigation channel in Lower Pool 4. Specifically, the project utilizes up to 300,000 cubic yards of dredged sand and sediment removed from the Reads Landing Dredged Material Placement Site. The Corps utilizes both hydraulic and mechanical dredging methods across its Upper Mississippi River operations to remove this material from the riverbed and transport it to the placement sites where the new islands and peninsulas are being constructed (USACE 2026b).

The Upper Pool 4 region supports a wide array of wildlife, including waterfowl, aquatic mammals, and game fish like bluegill, bass, and crappie (USACE 2026b). The area is also home to several rare and protected species. The federally endangered Higgins' eye pearly mussel is a known resident of the Upper Mississippi River system, heavily impacted by invasive species and habitat changes. Additionally, the region supports state-listed Species in Greatest Conservation Need, such as the endangered crystal darter, the bluntnose darter, and the threatened paddlefish that inhabits Lake Pepin and relies on deep, open water (WDNR n.d.). While long-term biological results (such as the return of submerged vegetation and game fish) for this restoration effort project will not be monitored until after final completion (USACE 2026b), it is anticipated that this project will provide significant benefit as the restoration techniques implemented has a long track record of success.

Related Projects in the Region:

Website Links:

Videos:

MVP Public Affairs. (2019, February 22). Pepin & Pig's Eye, using dredge material to improve habitat. [Video]. YouTube.

References: