Reducing the Flooding Concern near the 28th Street Pump Station
Residents of Council Bluffs, Iowa, were aware of the threat of flooding and the burden of evacuating their homes because of the potential of the levees failing. In response, the City planned for capacity upgrades of the 28th Street Storm Water Pump Station and the upstream storm sewers. During the 2011 Missouri River flood, the City and the U.S. Army Corps of Engineers plugged the 28th Street Storm Water Pump Station and the 60-inch-diameter pipe under the Missouri River levee to prevent failures that would endanger the levee. The pump station was damaged because of the pressure from the river and, therefore, the station needed to be rehabilitated.
To address the concerns, GBA was retained to evaluate concepts for the new 28th Street Storm Water Pump Station. The study included development of cost estimates for the new pump station and an analysis of the incremental cost increase to convey the one-year, two-year, and five-year storm events.
Upon completion of the study, the City contracted with GBA to design the new pump station, obtain the necessary permits, and to sub-contract the geotechnical investigations necessary for the new pump station.
The concept behind the new station features three phases, each with a capacity upgrade to match planned upstream conveyance system improvements. The first phase, currently under construction, consists of structures sized for the ultimate station, four 36-inch welded-steel discharge pipes to the edge of the Missouri River, and two 215-horsepower non-clog submersible pumps with a combined capacity of 80 cubic feet per second. The ultimate pump station design plans for four 280-horsepower mixed flow pumps with a combined capacity of 250 cubic feet per second.
With construction underway, GBA provided a full-time resident project representative to oversee the daily operations. Mike Hart, GBA’s design lead and resident representative, has been on the job site since 2013 and will be there until the project is completed at the end of 2014.
The project provides the first step toward Council Bluffs residents being able to breathe easier when there is a threat of rain. In the near future, reoccurring flooding will simply be a memory.
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Archive: Client Spotlight