The City of Coralville’s flood protection system has received the Grand Place Award for engineering excellence in the special projects category of the 2015 American Council of Engineering Companies of Iowa (ACEC/Iowa) Engineering Excellence Awards Competition.
About the AwardThis award recognizes an outstanding engineering achievement in Iowa that demonstrates innovation; adds value to the engineering profession and the public; and represents successful social, economic, and sustainable design considerations.
Flood Protection SystemShoemaker & Haaland worked with the City of Coralville to design a flood protection system following the 2008 flood. The project, the Coralville CRANDIC Rail Corridor Flood Protection System, is designed to protect the city from flooding of the Iowa River to an elevation of one foot above the 2008 high water elevation. This project is one element of an overall flood protection project that will protect the citizens and businesses of Coralville from future floods similar to the 2008 floods. The project was funded through the United States Economic Development Administration, Community Development Block Grant, and City of Coralville funds.
The mile-long flood protection system is on the west side of the Iowa River from the north end of the Iowa River Power Company Restaurant parking lot to CRANDIC Park in Iowa City. The project consists of a varied system of flood control measures, with an integrated maintenance access way that doubles as a multiuse trail system. Construction of the flood protection system along the Iowa River reclaimed a half-mile of riverfront and made it publicly accessible.
The project begins at the north end with 500 feet of “invisible” floodwall that is erected only when flood waters threaten and leaves an obstruction-free view when the barrier is removed. At the south end of that wall, an existing pedestrian bridge approach and abutment were retrofitted with permanent floodwalls. To continue the flood protection and the trail system south along the shoreline, a curved concrete slab bridge with an integrated pedestrian patio was constructed against the existing seawall of the Iowa River Power building, which is a former hydropower generation facility. Continuing south, a combination permanent concrete stem wall and “invisible” wall system protect the new multiuse trail and electrical substation. An earthen levee continues south along the top of the existing river bank to the mouth of Clear Creek where the existing railroad bridge over Clear Creek was demolished and the construction of a new, longer bridge allows unrestricted flood flows and lowers the height of future flood protection systems upstream in the Clear Creek watershed. The multiuse trail rides along the top of the levee before dipping below the bridge, thereby eliminating an at-grade railroad crossing. Beginning at the southern bank of the mouth of Clear Creek and continuing to CRANDIC Park, the existing Cedar Rapids and Iowa City Railroad embankment was raised and improved to make it suitable for use as a flood control levee. The flood protection is integrated into the elevated CRANDIC railroad embankment at the Rocky Shore Drive overpass in Iowa City.
Additional RecognitionThe project was also the recipient of the 2014 Outstanding Civil Engineering Project Achievement Award by the Iowa Section of the American Society of Civil Engineers.Pictured: City Engineer Dan Holderness with the 2015 Grand Place Award for Engineering Excellence in the Special Projects Category from ACEC/Iowa