The 2020 ACEC/Iowa Engineering Excellence Awards winning projects in the Transportation Category:

Transportation Grand Place Award (1st Place in Category)

Firm: HDR
Client/Owner: Iowa Department of Transportation
Project: 2019 Flood Response and Recovery Efforts
Contact: Mr. William Sharp
E-mail:  [email protected]  ~ Phone: 402-399-1074

In March 2019, widespread flooding impacted western Iowa, greatly exceeded the Missouri River levee system’s design capacity, resulting in 51 breaches and contributing to long-term flooding. The flood caused substantial overtopping and, ultimately, system failure resulted in nearly 60,000 acres flooding a 50-mile stretch of the Missouri River. The only state highway bridges that were open across the river from the Omaha-Council Bluffs metro area to the Missouri border were 125 miles apart. In addition to interstate travel, local roadway users were unable to reach jobs, schools, health care and other services.

Given the magnitude of flooding, severe impacts to users and extent of the damage, innovative technology and creativity were essential to completing the project as quickly and efficiently as possible. The team created a customized GIS storymap, which was updated daily to provide damage reports, status updates and photographs. Within days, a custom ArcGIS data collection app was in-use to automate the damage assessment data collection. The app included an intuitive, mobile interface that allowed field teams to capture data with map-driven forms.

The team also created a detailed 2D hydraulic model to provide decision support for flooding problems. With more than 1 million wet cells at the peak of flooding, this was one of the largest 2D hydraulic models in the region. The modeling effort was complicated by incorporating levee breaches, the expansive flooding and features such as roadways and culverts. Throughout the Spring and Summer flooding, the model simulated the closure of the levee breaches as they were repaired. The problem was compounded by levee breaches, new channels eroded in the floodplains, debris, flood damage to roadways, and intentional breaches of setback or floodplain levees to enable drainage.

With communications efforts at the forefront, the project team had to continually inform the traveling public and stakeholders of roadway segments that were re-opening. Local stakeholders were sent emails with graphics and detailed travel movements, restrictions and other key items. Notifying the public was done via Iowa DOT communications press releases, the 511 travel information system, social media and a statewide flood recovery website.

FHWA’s emergency response program provides reimbursements for betterments that go above and beyond replacement in kind, if they add cost effective resiliency. Betterments were a focus of recovery efforts because this was the second time in eight years that Iowa DOT had major interstate closures due to Missouri River floods. The primary betterment provided was the Flexamat shoulder protection — its first use in Iowa. Proof of its effectiveness was apparent in late May, as river waters rose again. The roads with Flexamat installed were re-opened hours after the waters receded with no new damage to the shoulders or roadway.

Emergency response for bridges on I-29, focused primarily on bridges at mile marker 8.5. Iowa DOT teams first indicated no major concern at this location after the initial flood event. These twin bridges were originally designed to span an abandoned rail line, turned county road and were not designed for high flow rates and scour.

Water from the levee breaches caused significant flow and scour under these bridges, threatening collapse. Survey data estimated that scour had reached the last couple of feet on one pier. Due to safety and stability reasons, the bridge was immediately closed. To quickly repair the bridge and restore traffic, Iowa DOT direct selected a contractor to work with the HDR team on this emergency situation. The contractor first built a dike to stop active flow under the bridge and then used a telescoping, belt-driven conveyor to get materials over the bridge deck and stabilize the site. Once stabilized, part of the deck was removed and piles were installed around the damaged pier, finally to be cast in concrete.

While the fight is far from over, the Iowa DOT continues to prioritize innovative project delivery and design solutions to restore mobility and provide resiliency as quickly and safely as possible. 

Transportation Honor Award (2nd place in category)

Project: MAASTO Regional Truck Parking Information System
Firm: HNTB
Client/Owner: Iowa Department of Transportation

Project:  US 30 and Grant Road Intersection Improvements
Firm:  Snyder Associates
Client:  City of Carroll



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