Who (not what) drowned New Orleans?

A short while ago, we were discussing the levee breaks -- or canal breeches -- in New Orleans. I took some heat for suggesting that the matter was rather more mysterious than most have presumed. Several named witnesses have reported hearing explosions.

Today, no less august a source than the Washington Post chimes in:

The Army Corps of Engineers has said that Katrina was just too massive for a system that was not intended to protect the city from a storm greater than a Category 3 hurricane, and that the floodwall failures near Lake Pontchartrain were caused by extraordinary surges that overtopped the walls.

But with the help of complex computer models and stark visual evidence, scientists and engineers at Louisiana State University's Hurricane Center have concluded that Katrina's surges did not come close to overtopping those barriers. That would make faulty design, inadequate construction or some combination of the two the likely cause of the breaching of the floodwalls along the 17th Street and London Avenue canals -- and the flooding of most of New Orleans.

In the weeks since Katrina drowned this low-lying city, there has been an intense focus on the chaotic government response to the flood. But Ivor van Heerden, the Hurricane Center's deputy director, said the real scandal of Katrina is the "catastrophic structural failure" of barriers that should have handled the hurricane with relative ease.

"We are absolutely convinced that those floodwalls were never overtopped," said van Heerden, who also runs LSU's Center for the Study of Public Health Impacts of Hurricanes.

More:

"This should not have been a big deal for these floodwalls," said oceanographer G. Paul Kemp, a hurricane expert who runs LSU's Natural Systems Modeling Laboratory. "It should have been a modest challenge. There's no way this should have exceeded the capacity."

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.

If we are dealing with shabby design, as opposed to deliberate sabotage -- well, that's still scandal enough to satisfy any scandal-watcher.

Even so, I hope the investigators do not dismiss out of hand the reports of explosions. Bursting dams was, apparently, an art that became highly developed during the course of WWII.

I would note that the affected area of the 17th Street Canal underwent a still-unexplained bout of reconstruction earlier this year: "One project that a contractor had been racing to finish this summer was a bridge and levee job right at the 17th Street Canal, site of the main breach on Monday."

And who was that contractor? That, it would seem, is the question of the moment.