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August 19, 2011
The U.S. Army Corps of Engineers is not using the best methods or timing to armor levees in the New Orleans area and it should not proceed until better methods are considered and evaluated, the Louisiana Coastal Protection and Restoration Authority (CPRA) asserted during its August meeting.
In 2006, following Hurricane Katrina, Congress directed the Corps of Engineers to armor the New Orleans area Hurricane Protection System to prevent future failures when storm surge overtops levees, floodwalls or other structures. After conducting research on the best technologies, the Corps recommended that grass be used in a number of areas as an armoring measure.
“The problem with grass and some of these other recommendations is that there are places where the levees will be raised in a couple of years. If you put the armoring down by next June, it will have to be removed to raise the levees and you’ve wasted all of that money,” said CPRA member John Barry.
A resolution calling on the Corps to thoroughly evaluate all armoring options was passed unanimously by the CPRA during its monthly board meeting in Baton Rouge.
Following Hurricane Katrina, the U.S. Congress authorized and appropriated more than a billion dollars in funding for the Corps of Engineers to design and construct the Greater New Orleans Hurricane Protection System (HPS) to strengthen and provide 100-year level of protection.
As a component of that protection system, the Corps formulated a plan to armor critical elements of the HPS and presented that plan to the State of Louisiana on June 6 of this year. The plan relies on grass and reinforcing mats to reduce scour and erosion that would occur from overtopping of levees. In a written response on June 24, the State said it strongly disagrees with the materials and methodologies the Corps is proposing and recommended that alternatives be considered and evaluated.
“New levees naturally undergo initial settlement and subsidence and soon need to be uplifted as a matter of course,” said John Monzon, protection engineer with the State Office of Coastal Protection and Restoration. “There is no provision for the Corps to come back and re-armor after the uplift is made. We think other options should be considered. One alternative is to increase the height of the levees now because this will prevent overtopping and subsequent erosion, and it can be done in such a way that the additional heightening can be removed temporarily when it is time to do the inevitable and necessary uplifting. The best time to install armoring is after the final uplift. Then it will have a much longer life and will be more economically viable.”
CPRA Chairman Garret Graves, who also heads the Governor’s Office of Coastal Activities, said this is about resiliency and protecting the protection infrastructure to achieve the best long term viability of the system. He believes the Corps is on the wrong path.
“Local flood protection authorities and levee districts are questioning this, too,” said Graves. “We all have serious doubts about what the Corps is doing; is it even adequate? We want the Corps to conduct a more thorough analysis. They need to hear us and allow us to present alternative methods and materials, and then give our research and our concerns the consideration they deserve.”