In First, Corps Allows Iowa Town To Raise Levees
The Omaha Engineer District and the city of Hamburg, Iowa, signed a Section 1176 project agreement February 10 that will allow for raising the Hamburg Ditch 6 levee 8 feet, significantly increasing the benefits the levee provides to the city.
The agreement came after the Omaha District, city and other stakeholders worked with Corps Headquarters and the Northwestern Engineer Division to implement the Section 1176 authority from the 2020 Water Resources Development Act. This is the first project across the nation to utilize the Section 1176 authority to raise the height of a federal levee system.
“I’m excited to join Mayor Cathy Crain and the city of Hamburg on this important project agreement to raise flood protection around the city of Hamburg,” said Col. Mark Himes, commander of the Omaha district. “I look forward to working with the city in the upcoming construction this spring.”
The Hamburg Ditch 6 levee was overtopped and sustained severe damage during the 2019 floods, leading to significant flooding within the city. Under the PL 84-99 program, the U.S. Army Corps of Engineers can restore levees active in the program to their pre-flood congressionally authorized elevation.
Section 1176 allows a levee sponsor, at their own cost, an avenue to raise the elevation of a levee above its current congressionally authorized elevation. Raising levees can be controversial, and some downstream towns have argued that raising levees increases downstream flooding risk. But the Hamburg team developed engineering drawings and completed studies showing that the modified levee will not produce adverse impacts as a result of the raise. In total, Hamburg, with support from other stakeholders, will contribute $7-8 million to raise the Ditch 6 levee to its new elevation and provide additional flood risk management benefits to the city.
The construction contract for this project was recently advertised, and construction should start soon.
Although significant strides have been made in repairing the more than 350 miles of levees across the Lower Missouri River Basin that were damaged following the historic floods of 2019, a heightened level of flood risk remains for the communities and landowners behind these damaged levee systems as repair efforts are ongoing. This risk is higher than it was prior to the flood event because the levees include a series of components that all function together as a system. Until all of these components, (such as seepage berms and relief wells) are repaired, the system does not fully provide the same level of flood risk reduction as it did in its pre-flood condition.