The levee system that protected New Orleans from hurricane-caused surges along Lake Pontchartrain was never designed to survive a storm the size of Hurricane Katrina, the Army Corps of Engineers said Thursday.
The levees were built to withstand only a Category 3 storm, something projections suggested would strike New Orleans only once every two or three centuries, the commander of the corps, Lt. Gen. Carl A. Strock, told reporters in a conference call. Katrina was a Category 4 storm.
"Unfortunately, that occurred in this case," Strock said.
Strock said that the levee system's design was settled on a quarter of a century ago, before the current numerical system of classifying storms was in widespread use. He said that studies had begun recently on strengthening the system to protect against Category 4 and 5 hurricanes, but hadn't progressed very far.
Strock added that despite a May report by the Corps' Louisiana district that a lack of federal funding had slowed construction of hurricane protection, nothing the Corps could have done recently would have prevented Katrina from flooding New Orleans.
"The levee projects that failed were at full project design and were not really going to be improved," Strock said.
Strock's comments drew immediate criticism from flood-protection advocates, who said that the Corps' May report was a call for action and a complaint about insufficient funding, and that no action took place.
"The Corps knew, everybody knew, that the levees had limited capability," said Joseph N. Suhayda, a retired director of the Louisiana State University's Water Resources and Research Institute. "Because of exercises and simulations, we knew that the consequences of overtopping (water coming over the levees) would be disastrous. People were playing with matches in the fireworks factory and it went off."
Suhayda, an expert in coastal oceanography, said, "the fact the levee failed is not according to design. If it was overtopped, it's because it was lower in that spot than other spots. The fact that it was only designed for a Category 3 meant it was going to get overtopped. I knew that. They knew that. There were limits."
Some critics Thursday questioned the usefulness of levees, saying that all of them fail eventually.
"There are lots of ways for levees to fail. Overtopping is just one of them," said Michael K. Lindell, of Texas A&M University's Hazard Reduction and Recovery Center. "There's a lot of smokescreen about `low probabilities.' Low probabilities just means `Takes a long time.'''
Strock said that stopping the flow of water over the levees has proved to be "a very challenging effort."
Engineers have been unable to reach the levees themselves and have had to draw up plans based only on observations from the air, he said. "We, too, are victims in this situation," he said.
In Louisiana, Army Corps officials said they hoped that one break, in what's known as the 17th Street Canal, might be closed by the end of Thursday, but that a second break in the London Avenue canal is proving more intractable.
Short sections of the walls that protected the city from the waters of Lake Pontchartrain caved in under storm surges, including an area that recently had been strengthened.
A fact sheet issued by the Corps in May said that seven construction projects in New Orleans had been stalled for lack of funding. It noted that the budget proposed by President Bush for 2005 was $3 million and termed that amount insufficient to fund new construction contracts.
"We could spend $20 million if the funds were provided," the fact sheet said. Two major pump stations needed to be protected against hurricane storm surges, the fact sheet said, but the budgets for 2005 and 2006 "will prevent the corps from addressing these pressing needs."
Acknowledging delays in construction, Corps officials in Louisiana said that those projects weren't where the failures occurred. "They did not contribute to the flooding of the city," said Al Naomi, a senior project manager.
"The design was not adequate to protect against a storm of this nature," he said. "We were not authorized to provide protection to Category 4 or 5 design."
(c) 2005, Knight Ridder/Tribune Information Services.
Need to map