NEBRASKA CITY – The U.S. Army Corps of Engineers hosted a scoping meeting at Nebraska City Tuesday to encourage public input on its congressionally authorized study aimed at increasing flood protection along the lower Missouri River and building resiliency among its residents.

Tony Krause, flood risk program management coordinator, said the study is looking for solutions that are considered resilient or sustainable.

Krause: “Typically that means they achieve the 3 Ps of sustainability – helping people, helping the planet and producing profits. In this context, we’re looking at things that help people by reducing flood risk. We’re looking for ways to improve and increase habitat benefits for the planet. We’re looking at things that are justified economically to achieve that profit goal.”

 

 

After the 2019 flood, the Iowa Department of Transportation raised Highway 2 and built two overflow bridges that allowed the Corps of Engineers to move the levee connection and open an additional 800 acres for high water to flow through without overtopping the levee.

Re-alignment of a levee  also occurred downstream near Hamburg where there have been at least three breaches.

A levee setback project involving Atchison County, Kan., and Holt County, Mo., opened up 1,000 acres to give flood waters more space and reduce wear and tear on the levee.

 

 

Greg Johnson, chief of the plan formulation section of the Omaha District Corps of Engineers, said the levee work near Nebraska City and Hamburg are useful examples.

Johnson: “Certainly both of those concepts, because of their focus on increasing the conveyance capacity of the river channel, certainly could have applicability in other reaches of the river to increase resiliency.”

With the relaxing of the pinch point at Nebraska City, maps show the next downstream narrowing at the Highway 136 bridge at Brownville.

Johnson: “That bridge, as well as many of the bridges up and down the system, are kind of bottlenecks. The bridges were installed much narrower than the flood plain as a whole, so, if there are opportunities to look at improving those bridges and then looking at re-aligning levees at the same time, it definitely could increase carrying capacity conveyance and a resiliency for those levee systems and those communities in the surrounding area.”

 

A  four-mile stretch of Levee 575 near Nebraska City had been repaired after the flood of 2011. The slope of the backside of the levee was built at a 3 to 1 ratio when the levees were built in the 1940s and ‘50s, but Levee 575 was re-built after 2011 with a 5 to 1 slope ratio. Engineers said that ratio held up much better after the levee was overtopped.