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U.S. Army Corps of Engineers
St. Paul District
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332 Minnesota St., Suite E1500
St. Paul, MN 55101

Phone: (651) 290-5807
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Corps seeks public comments on Upper Pool 4 island project modifications

U.S. Army Corps of Engineers, St. Paul District
Published May 11, 2022
Updated: May 11, 2022

The U.S. Army Corps of Engineers, St. Paul District, is seeking public comments on its draft Supplemental Environmental Assessment, or supplemental EA, released today, May 11, for proposed modifications to the Pierce County Islands in Upper Pool 4 of the Mississippi River. 

Corps officials initiated a feasibility study in 2017 to identify steps that could be taken to improve the habitat in Upper Lake Pepin, particularly in Catherine Pass. These measures include islands, water level management structures, overwintering dredging and shoreline protection. The proposed solutions are designed to work together to reduce sediment and increase water clarity within the area. The features include four islands, refuge dredging, a water level management dike and control structure, an access road, two backwater dredged areas, three areas of shoreline protection, a mudflat, access dredging and a partial closure of Catherine cut.

Detailed engineering and design studies conducted since the completion of the Integrated Feasibility Report and Environmental Assessment in 2020 resulted in several proposed modifications to the project. The modifications identified since the IFR/EA include: two additional mudflats with berms and rock protection, creation of four pothole wetlands and additional access dredging. A supplemental EA and Supplemental Clean Water Act Section 404(b)(1) evaluation have been prepared to address the potential effects associated with the proposed modifications.

The draft documents describing the project and the environmental impacts in detail are available to the public and can be viewed and downloaded from the St. Paul District website at:

Comments should be submitted no later than Jun 11. Questions on the project or comments on the supplemental EA can be directed to Nick Vottero, project manager, at 651-290-5316 or Please address all formal written correspondence on this project to the St. Paul District, U.S. Army Corps of Engineers, ATTN: Regional Planning and Environment Division North, 180 5th St. E., Suite 700, St. Paul, MN 55101.


Public Affairs

Release no. 22-047