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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

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Corps of Engineers seeks public comments on Sny Magill-Effigy Mounds National Monument shoreline protection project

U.S. Army Corps of Engineers, St. Paul District
Published June 20, 2024

The U.S. Army Corps of Engineers, St. Paul District, is seeking public comments on its draft plan to protect the Sny Magill-Effigy Mounds, near Guttenberg, Iowa, along the Mississippi River.

The draft plan includes constructing a nearly 2,000-foot linear rock berm along the shore to protect the site. The Sny Magill Unit is a part of the larger Effigy Mounds National Monument and is located within the Upper Mississippi River Pool 10, along Johnsons Slough. The mounds are a unique, highly significant cultural resource that is a sacred landscape to the 19 culturally associated tribal nations. The Sny Magill unit is under immediate threat due to ongoing shoreline erosion.

The monument is managed by the National Park Service and the area east of the Sny Magill unit is part Upper Mississippi River National Wildlife and Fish Refuge, which is managed by the Fish and Wildlife Service. Coordination and consultation with tribal nations is ongoing. If the project is approved, the boat launch at Sny Magill would be temporally closed in spring/summer 2026 for construction.

Questions on the project or comments on the draft environmental assessment can be directed to LeeAnn Glomski at The documents are available on the St. Paul District website at: Please address all formal written correspondence on this project to District Engineer, St. Paul District, Corps of Engineers, ATTN: Regional Planning and Environment Division North, 332 Minnesota Street, Suite E1500, St. Paul, Minnesota 55101. The deadline to submit comments is July 20.

An open house will be held June 25, from 5:30-7 p.m. at the Effigy Mounds National Monument Visitor Center, 151 Highway 76, Harpers Ferry, Iowa.

Public Affairs

Release no. 24-042