Experts Say Faulty Levees Caused Much of Flooding

The center's researchers said it is too early to say whether the breaches were caused by poor design, faulty construction or some combination. But van Heerden said the floodwalls at issue -- massive concrete slabs mounted on steel sheet pilings -- looked more like the sound barriers found on major highways. He also suggested that the slabs should have been interlocked, and that the canals they were supposed to protect should have had floodgates to keep out water from the lake.

Former representative Bob Livingston (R-La.), who helped lead the charge for Corps projects in Louisiana when he chaired the House Appropriations Committee, noted that the earthen levees along Lake Pontchartrain had all held, while the concrete floodwalls had failed. He was especially concerned about the 17th Street barrier, saying it "shouldn't have broken."

"I don't know if it's bad construction or bad design, but whoever the contractor is has a problem," said Livingston, now a lobbyist on Capitol Hill.

Former senator J. Bennett Johnston (D-La.) said he remembers numerous briefings from Corps officials about the danger of a hurricane overtopping the New Orleans levees. But he said he never envisioned a scenario like this one. "This came as a surprise," he said.

The Corps has not identified the contractors who built the floodgates that failed; Paul Johnston said there will be a full investigation into the breaches.

Congress authorizes flood- control projects -- after receiving recommendations from the Corps -- and the Corps oversees their design and construction.

John M. Barry -- who criticized the Corps in "Rising Tide," a history of the Mississippi River flood of 1927 -- said that if Katrina did not exceed the design capacity of the New Orleans levees, the federal government may bear ultimate responsibility for this disaster.

"If this is true, then the loss of life and the devastation in much of New Orleans is no more a natural disaster than a surgeon killing a patient by failing to suture an artery would be a natural death," Barry said. "And that surgeon would be culpable."

Glasser reported from Washington.