Iowa Under Water - Featured

The Story of the UI Cofferdam

June 15, 2008 - 2:25 PM

CofferdamOn March 8th, 2007, the University of Iowa embarked upon the North Chilled Water Crossing Project. The purpose of the project was to bring chilled water from the west side of the Iowa River over to the east side in order to provide additional cooling capacity for new building renovations and construction. Little did they know that this supposed 2.5 month project, due to be completed by June of 2007, would become fuel for the already raging disaster flood conditions in the summer of 2008.

Problems with this project began shortly after it started and over one year later, the project was still not completed. The project involved building a cofferdam in the Iowa River to create a dry area for workers to install chilled water pipes under the river. Here is a rough timeline of events:

  • 2006 - University approves the North Chilled Water Crossing Project with a $7 million budget
  • March 2007 - Work begins on construction of the cofferdam
  • May 16, 2007 - The cofferdam collapses in the Iowa River and workers narrowly escape harm
  • June 2007 - Engineers evaluate the situation and begin making plans to repair the collapsed dam
  • July 2007 - High waters impede work on the project and work carries on into the fall and winter months
  • March 2008 - Crews are still working to evaluate, fix and stabalize the cofferdam. Officials are "relying" on good weather to get the project completed.
  • June 2008 - It becomes evident that Iowa City will face a major flood event along the lines of the 1993 floods
  • June 9, 2008 - As the waters top the spillway at the Coralville Dam, University of Iowa officials inform the public that the cofferdam is severely restricting flow in the Iowa River near the University. Businesses and residents upstream from the Dam will suffer even higher waters as a result. Some predictions say that flood waters could be up to 5 feet higher than normal because of the obstruction caused by the cofferdam.
  • June 11, 2008 - Crews work to fortify the cofferdam from another collapse due to the approaching record flows in the Iowa River.
  • June 13, 2008 - Flood waters rage and unprecidented flooding and damage to properties occurs in Iowa City and Coralville upstream from the cofferdam. Some buildings are in 5 - 6 feet of water. Many damaged properties were without flood insurance, and some are blaming the cofferdam as a contributor
I doubt anyone was thinking that increased upstream flooding wo

What the Army Corps of Engineers DID NOT Learn from the 1993 Floods

June 14, 2008 - 2:11 PM

In 1993, record smashing floods ravaged the state of Iowa much like they are this week. Although the floods happening right now are far worse than 1993, no one had ever seen or heard of a flood event of the magnitude that happened in '93. The floods of '93 caused wide spread damage to homes and businesses and were burned into the minds of every person that experienced them that year. After the floods, an joint enquiry was held between Iowa City, The City of Coralville, and the Army Corps of Engineers to determine if there was any way to more optimally regulate the outflow from the Coralville Reservoir and Dam that holds back the Iowa River north of Iowa City and Coralville.

In 1997, after several years of beurocratic meetings, the Corps of Engineers determined, suprisingly, that "There is no Federal interest in a study of the optimal regulation of the reservoir." The Corps was unwilling to hear any public input regarding this decision and ceased any efforts on developing a written contingency plan for lake operation in the event of a flash flood.

In spite of the firm decision handed down to the public by the Corps of Engineers, Larry Molnar and Charles Newsome wrote a review of some of the major procedural and technical flaws of the Corp's decision. In their report, Larry and Charles suggest that the Corps was ignoring an opportunity to take some factors into account when optimizing the regulation of the reservoir. Among other things, Larry and Charles mention a potential long-term climate shift that was not a consideration in the original design of the reservoir and dam. This reference to Global Warming, would most likely be well received today, but in 1997, it was dismissed without further discussion. This report was forwarded on to the Corps of Engineers in 1997 and I can find no record of any response to it from the Corps.

Leading up to this event, I watched the Corps of Engineers restrict the outflow of the Coralville Dam to well below capacity for weeks, while at the same time hearing others warn of an impending flood event. I am not an expert in hydrological events, and I am struggling to understand the theory behind the reservoir management protocols. I suspect that there is more to the story than meets the eye. I'm confident that the Corps of Engineers has followed protocols in this event and is not to blame for the flood occurring today. I wonder if it would have been possible for anyone to construct a new reservoir management protocol that could have protected us from this event.