When Hurricane Katrina made landfall just south of New Orleans in August 2005, levees protecting the low-lying city from Lake Pontchartrain and the Mississippi River failed, causing catastrophic flooding in the city.
The U.S. Army Corps of Engineers has been repairing the levees since then. (See "New Orleans' Rebuilt Levees 'Riddled With Flaws'" [May 6, 2007].)
"If [Gustav] is a Category 3 that's going to central Louisiana [far west of New Orleans], we're fine," said Oliver Houck, a professor of environmental law at Tulane University in New Orleans.
The New Orleans levees have "more armor" than before Hurricane Katrina, Houck said. But that extra protection is mostly in the form of additional sandbags, he added.
"Clearly it's a stopgap measure," Houck said. "But stopgap measures ought to handle an indirect hit from a Category 3."
Still, Houck said, "I think the city would be wise to call for an evacuation, which I think is inevitable."
Yesterday, Louisiana governor Bobby Jindal called a mandatory evacuation, probably beginning no earlier than Saturday, "very probable," according to the New Orleans Times-Picayune.
Concerns Not Resolved
In May 2007 Bob Bea, an engineering professor at the University of California, Berkeley, was highly critical of the repairs that the Army Corps of Engineers had made to New Orleans since Hurricane Katrina.
The repaired levees would not withstand the impact of a storm similar to Katrina, Bea said at the time.
Asked this morning if his concerns from 15 months ago had been resolved, Bea said, "No."
He did say, however, that the levees would be less likely to fail if Gustav's center—with the storm's strongest winds—stays well to the west or east of New Orleans.
But Bea and Tulane's Houck agreed that if the eye comes ashore just to the west of New Orleans or goes directly over the city, the city will be in deep trouble.
A direct hit from a Category 3 hurricane could send water surging up the Mississippi River Gulf Outlet canal into New Orleans, Houck said. The narrowness of that waterway could cause the water to rise to as high as 17 feet (5 meters) as it rushes into the city, he said.
UC-Berkeley's Bea said, "If you directly challenge that flood-protection system today with a Category 3 storm surge, you can expect to see very, very significant breaching of the levees.
"That's why, if I lived in New Orleans, I'd get in my car and get out early and safely."
Willie Drye is author of Storm of the Century: the Labor Day hurricane of 1935, published by National Geographic Books.
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