Upper Mississippi River – Navigation and Ecosystem Sustainability Program (NESP) Systemic Mitigation Island 4 Project

U.S. Army Corps of Engineers, St. Paul District
Published April 12, 2024

The primary purpose of the project is to address general degradation of habitat quality due to sediment deposition, wind-driven wave action, declining bathymetric diversity, and a decline in aquatic vegetation.

The project area is located near the head of Lake Pepin in Upper Pool 4 of the Mississippi River, between river mile 784 and 792 in the backwater complexes adjacent to the main channel. The nearest community is Bay City, Wisconsin.

Sedimentation and sediment resuspension caused a loss in water depth diversity of the backwater lakes and isolated wetlands above Lake Pepin as well as a loss in aquatic vegetation. Concerns over habitat deficiencies in Upper Pool 4 include reduced habitat diversity and quality, lack of aquatic vegetation and invertebrates, and reduced abundance of fish and wildlife.

The project includes construction of a peninsula to improve habitat conditions by reducing wind, waves, and redirecting sediment inflows. It also includes overwintering dredging to support a deep water habitat for fish and bank and shoreline stabilization to reduce inflows and erosion during high flow events.

Island 4 was initially a feature of the Section 1122 Upper Pool 4 Pierce County Islands project that was awarded in September 2022. This feature was removed from this project during the design phase due to funding constraints. Island 4 was initiated as a stand-alone project in December 2022 as part of the NESP systemic mitigation.

The team completed the design phase and awarded a construction contract in summer 2023. Construction will commence in spring or early summer 2024 and is estimated to be completed by in early 2026.

NESP was authorized in the Water Resources Development Act of 2007 (Title VIII) to construct small-scale navigation improvements, seven new 1,200-foot lock chambers and ecosystem/habitat restoration.

Project design, construction, and operation and maintenance costs are 100% federally funded. This is a systemic mitigation project, compensating for projected increases in barge traffic, and NESP Navigation projects are 100% federally funded.

Estimated Project Costs:
Construction contract: $8,654,530
Other funds allocated to date: $204,000