Wednesday, April 26, 2006

U.S. Army Corps of Engineers Absolves Itself: Part 2

At first glance, this seems absurdly obvious:
"Katrina was a storm that was significantly stronger than the protection system was designed for," Hitchings said.
When I read this quote by Dan Hitchings, the civilian head of the USACE’s Task Force Guardian, I thought it should go in the “No Shit, Sherlock” file.

I was wrong. It is crucial.

Many of us have blamed the USACE for the failure of the levee system. We can’t do that if “Katrina was a storm that was significantly stronger than the protection system was designed for.” If this is true, the levee system was designed properly, built properly, and functioned properly. It just wasn’t built to withstand a Katrina.

This would absolve the USACE and the federal government of any blame for the failure of the levee system and, therefore, any obligation to make up for it.

That is the conclusion the federal government wants. And they are looking for the evidence to support it:
An upcoming report sponsored by the corps will show maps of the inundation of the metro area, including what conditions would have been like if levee walls had not breached, said Dan Hitchings, the civilian head of Task Force Guardian, the corps' effort to rebuild New Orleans area levees to pre-Katrina levels.

"The breaches just made it worse," Hitchings told the House Transportation Committee in a special hearing Monday. Setting the breaches aside, "We will all be surprised at how much water still came into the system."


His remarks stunned some members of the committee who have attributed much of the flooding, particularly in Lakeview, Gentilly, Old Metairie and many areas in Orleans Parish and downtown, to breaches in the 17th Street and London Avenue outfall canals, which were not overtopped.


"A lot of that flooding came from the Industrial Canal as well," he said, adding that overtopping on the west side of the canal contributed to more flooding in the city than people generally know.

As for flooding in the Lower 9th Ward, St. Bernard Parish and eastern New Orleans, those waters were because of a combination of levee overtopping and to breaches caused by the overtopping, Hitchings said.
I am as stunned to hear this as the committee members. With all the media stories done on the levees, with all the press conferences held by the USACE, and with three different groups (IPET, Team Louisiana, and the Berkeley Group) investigating the levees, I am surprised that this is the first I have heard that “the breaches just made it worse” or that a significant amount of water overflowed the west (upper) side of the Industrial Canal.

Such an overwhelming surge overtopping the levees to the point where the breaches didn’t matter would certainly absolve the USACE. But, other experts aren’t so sure that’s what happened.

Assistant director of the LSU Hurricane Center Ivor van Heerden:
Van Heerden said storm surge models show 16 percent of the volume of water in the Orleans metro bowl, basically the area west of the Industrial Canal, was from overtopping, and the rest from breaches. Breaches were responsible for 92 percent of the flood water volume in St. Bernard Parish and 65 percent in eastern New Orleans, he said.

Overtopping would have occurred for up to three hours the day of the storm, totaling nowhere near the amount of sustained water flowing in because of breaches, he said.
University of Missouri-Rolla engineering professor J. David Rogers:
"But for Lakeview and Gentilly, I don't know what he is talking about," Rogers said of Hitchings.

There was overtopping on the western side of the Industrial Canal, but for at most six hours, he said. "It's not what caused everybody to leave their homes," Rogers said. "As a percentage of property damage, it's not significant."
I eagerly await the June report. I am not an engineer. Nor do I play one on this blog. But I am sure plenty of engineers will comment on it when the report comes out. If the science is good, then the report will be good, giving us more information on how to build a levee system that works.

If, however, the USACE’s report varies drastically with the conclusions of other independent examiners, I don’t know where we go from there. We’ll see in June.

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