A new report finds the U.S. Army Corps of Engineers built the New Orleans area levee system with appropriate guidelines and was generally justified when it sought waivers from those guidelines.
The Advocate reports the Water Institute of the Gulf released the report on May 21 as the state and local entities continue to take over operation and maintenance of the system.
The Water Institute set up a six-member expert panel from around the country to evaluate the guidelines used to build the risk reduction system and four waivers to that design.
The waivers included resiliency design checks for the Inner Harbor Navigation Canal, steel pile corrosion protection, use of spiral welded pipe for foundations and deflections of proposed Inner Harbor Navigation Canal floodwall.
Generally, the waivers were appropriate and consistent with standard practices, said panel member Robert Gilbert, of the University of Texas.
However, he said, the waiver for adding additional steel to pilings used in a 23-mile section of floodwall in St. Bernard Parish wasn’t consistent with current practices.
Normally, the steel piles that support the floodwall underground would be coated with a substance to stop corrosion, Gilbert said. To save time, the Corps decided to increase the size of the pilings to account for any corrosion.
“It will now be the responsibility of the state to monitor these pilings,” Gilbert told the Coastal Protection and Restoration Authority.
Several members of the authority said the state tried to protest the measure but didn’t prevail. Now, they say, it’s the local sponsors who will need to maintain the structure.
Gilbert said although it means the section of floodwall will need to be monitored more closely, “this doesn’t mean the sky is falling or that the wall won’t work when a hurricane comes.”
Ken Holder, spokesman with the Corps office in New Orleans, said corrosion was an important design consideration in building the system and the Corps uses several different ways to control for corrosion, including coating the pilings or using more steel thickness.