Muscatine Levee Improvements

The Mississippi River has fostered growth in Muscatine, Iowa, for generations — but it also involves flood risk.

An area of over 30,000 acres in Muscatine and Louisa counties is protected by the Muscatine Island Levee District, including over 14 miles of levee. This shelters about $850 million worth of property — including homes, schools, factories, and important water and power plants — and nearly 5,000 people. 

Previously, the incipient point of the levee, which would overtop first in a major flooding event, was immediately next to occupied industrial areas and near the upstream end of the levee.

“Flooding is always dangerous, but it’s critical to prevent high velocity flood damage. Overtopping upstream in any levee system has the potential to be catastrophic for the protected area.” – Joshua Leyh, PE, CFM, Project Manager, Water Resources Engineer – Klingner & Associates, P.C.

The Klingner team came up with an innovative two-part solution. First, a three-mile section of the levee was improved to increase the profile and make it more resilient. Sand from the nearby Deep Lakes Park was used, which reduced costs and later created new fishing ponds as a bonus. Second, a special “hardened reach” was created about seven miles downstream. This serves as a safe overflow point where water can slowly spill over during extreme floods without breaching the levee. It also gives the City and counties more time to plan or evacuate if need be.

“This design lets floodwaters overtop slowly in a location designed to withstand it and give the community time to react.” – Joshua Leyh, PE, CFM, Project Manager, Water Resources Engineer – Klingner & Associates, P.C.

The hardened reach uses a special material called HydroTurf®, which has a grass-like appearance, but is resistant to erosion — the first material of its kind used in the Upper Mississippi River levee system. It can withstand powerful, rushing water without damage, and it does not require mowing or chemical sprays like typical earthen levees.

Another benefit of HydroTurf® is its attractiveness to local wildlife. One of the District’s primary concerns was the project’s interference with migratory waterfowl. Rather than using a concrete hard-scape, this material simulates the natural landscape and minimizes disruption.

“Having HydroTurf® in place is definitely going to protect us […]. Any time anything comes over it, it’s going to protect the city, it’s going to protect the farm ground, it’s going to protect the wildlife, and it’s going to protect our jobs. To me, it’s a huge advantage for Muscatine County, […] the state, […] and others that could use the same kind of concept and ideas.” – Rich Dwyer, Senior VP – Kent Corporation

Also integrated into the HydroTurf® design are 31 special filters to allow any trapped air and water to escape. This helps prevent pressure build up inside the system, especially when the levee is withstanding floods. The filters utilize the designed mesh size for the specific soil conditions to prevent levee material from eroding during seepage conditions.

“The filtration system means the hardened overtopping reach can be tested for extended periods of time without deteriorating. This is extremely important considering the duration of recent historic floods.” – Joshua Leyh, PE, CFM, Project Manager, Water Resources Engineer – Klingner & Associates, P.C.

If an extreme flood occurs, the new system gives the public much more time to evacuate safely — possibly reducing recovery time from years to weeks. After construction, USACE officials examined the reach, recognizing the potential for wider application.

This project was about more than just flood mitigation — it was an effort to protect local communities, businesses, farmland, and wildlife without interfering with the levee’s visual appeal or natural function. It demonstrates how an environmental challenge can be an opportunity to build local resilience.

The Muscatine Levee Improvements received an Honor Award from ACEC Iowa in the Special Projects category.