Repeated Mississippi River flooding is threatening prehistoric burial mounds that comprise Iowa’s only national monument, and the U..S. Army Corps of Engineers is looking for public input on plans to protect the area.
Kim Warshaw, the Corps project manager, says there are several reasons why the Effigy Mounds National Monument in Harpers Ferry is being placed at risk, though the mounds have been around many centuries. “The construction of locks and dams, climate change, altered hydrology, land use changes — have resulted in more frequent and prolonged high water events,” Warshaw says, “and this change in hydrology has increased wave action and ice action, causing erosion of shorelines and causing irreparable and unacceptable damage.”
The preserved area of northeast Iowa contains some 200 earthen mounds that are believed to have been built during the first millennium. Many of the mounds are shaped like animals, including bears and birds. About 100 of the mounds are in a low-lying area known as the Sny Magill unit, and that’s the section being damaged by the river.
Warshaw says, “The goal of this project is to preserve cultural resources, reduce bankline erosion, restore shoreline, reduce sedimentation within Johnson Slough, enhance the riparian habitat, and increase climate resiliency and hopefully, elevate our floodplain there.” Effigy Mounds is the largest known concentration of surviving mounds in the country, and the area is considered sacred by Native Americans as burial and ceremonial grounds. Warshaw says they’re consulting with multiple Native tribes, Iowa historic preservation experts, and the DNRs in Iowa and Wisconsin, as well as the National Park Service and the U.S. Fish and Wildlife Service.
“We’re considering different ways to protect those mounds,” Warshaw says, “and we’re looking at using river sand and using different types of rock to stabilize that shoreline to ensure that the mounds don’t continue to erode into the river.” She calls this a “once in a generation opportunity” to make a positive impact to restore the river’s ecosystem and to protect this rare bit of history for the future.
“We won’t ever be able to completely protect it,” Warshaw says, “but at least this way, we will ensure that the mounds are not sloughing off into the river, and we’re not losing those cultural resources forever. We’re hoping that maybe we can protect to a 50-year flood stage.” The Corps is asking for public input on the project before proceeding.
Comments can be emailed to: [email protected] or mailed to U.S. Army Corps of Engineers, St. Paul District, ATTN: Regional Planning and Environment Division North, 332 Minnesota St., Suite E1500, St. Paul, MN 55101. The deadline to submit comments is August 11th.