Would New Orleans levees hold for a second Katrina?
Five years after Katrina, New Orleans is rebuilding. The system designed to protect against future storms is better than before, but questions remain about whether it is fortified enough.
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The Corps says the reinforcements are built to provide a defense against a 100-year storm surge, which means protection against flooding that in any given year, may have a 1 percent chance of taking place. For a peak storm surge, such as one that may occur once every 500 years, the system is designed to allow overtopping, where a storm sends waves over the top of the wall. If that happens, a strengthened pumping system would remove the water in a matter of days and would not be considered as catastrophic as what happened during Katrina.Skip to next paragraph
In Pictures Hurricane Katrina: 5 years later
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100-year defense 'misleading'
John Barry, author of “Rising Tide,” a definitive history of the 1927 Mississippi River flood and a member of Southeast Louisiana Flood Control Authority East, which oversees six levee districts, calls the 100-year designation “misleading” because it implies the area is safe for that length of time.
But as years go by, the odds of a storm surge impacting the levee system increase. This will become especially true, he says, as coastal erosion brings the Gulf of Mexico closer to New Orleans, impacting sea levels and the strength of future storms.
“It’s the lowest standard in the civilized world. It’s government on the cheap,” he says.
Mr. Barry says the levees should be constructed to withstand a 1,000-year flood, adding that Holland enjoys a 10,000-year protection standard.
Raising minimum flood standards is costly. In 2007, Sacramento, Calif., area property owners agreed to finance $326 million of a $2.7 billion project to raise the flood protection standard of Folsom Dam to a 200-year level by 2015.
Risks never eliminated
However, Sinkler says the very nature of where New Orleans sits in relation to both the ocean and the Mississippi River means that whatever line of defense the Corps builds will never “eliminate all risk.” He says the current national standard for 100-year protection is “a political decision on how much risk the national and the local government is willing to accept.”
Mayor Landrieu says he plans to argue for increased protection, including pressing President Obama to make it a priority of ongoing recovery efforts.
“Until we get that we can’t comfortably say – to the extent that you ever comfortably say that you’re protected from Mother Nature – that we’re as well protected as we can for the risks that we know may be coming our way,” he says.
For some residents, the insecurity raised since Katrina persists. Diedra Taylor, who lives in a new home across the road from the levee breech that destroyed her old home, plus the majority of the Lower Ninth Ward, says she isn’t afraid that a second storm will undo the progress made over the last five years.
However, if a storm as powerful as Katrina is reported on the horizon, she is certain of one thing: “We’ll just leave. We won’t wait around to see if the Corps of Engineers did their job.”