06:01 PM CST on Tuesday, March 28, 2006

WWLTV.com

The following is an excerpt from an I-News interview with Dr. Ivor van Heerden, Assistant Director of the LSU Hurricane Center.

The Army Corps of Engineers has said its rebuilding area levee systems to pre-Katrina standards for the upcoming hurricane season, but a panel of experts that the corps commissioned to examine flood protection said they have grave concerns about the methods the corps has been using.

The American Society of Civil Engineers said in a letter to the corps that they believe the safety of the New Orleans area hurricane protection system is open to question.

Q: What was your reaction to the letter from the American Society of Civil Engineers to the corps of engineers?

A: Most importantly, it sent the signal to the corps that experts don’t believe the system is safe. I think that’s significant because folks returning need to understand what could happen in terms of the risks and probabilities.

Q: The American Society of Civil Engineers, in their letter, said that they are concerned about the I-walls, which still comprise a large section of the levees system, could be subject to failure.

A: That’s true; we have found sections of I-wall that didn’t fail in Katrina that we have grave concerns about. Some sections of I-wall such as along the Jefferson and St. Charles Parish, which only saw seven to eight feet of water during Katrina, but have skewed sections, and some lengths that are sag, indicating again these questions about the design and soil stability.

Q: The Corps of Engineers says we’ll be at pre-Katrina levels by June 1, do you feel we’ll be safe by June 1 from a Category 3 storm?

A: No, pre-Katrina levels is a category 2 as we found out in Katrina. Katrina was a fast moving, cat 3 storm that missed New Orleans, it was a miss, and it totally overwhelmed our system. So at best have protection from a category 2 storm.”

Q: The American Society of Civil Engineers is also concerned about soil conditions, that they weren’t examined closely enough; can all this be checked out by June 1?

A: It’s a mammoth task; our recommendations are that these three separate teams, the ASE, the University of California at Berkley, and Team Louisiana should in some way be frame worked together and then start a very detailed assessment of the levees.

Q: There are 38 miles of I-walls according to the Corps of Engineers, and you have been looking at some in Jefferson Parish, where it looks like some are sinking under its own weight, which suggests very weak soil conditions.

A: Yes, the first time I saw them was actually during Katrina from a helicopter and you could see the sags, they were that noticeable. Subsequently, we went to investigate them and it’s very obvious that the whole wall is sagging and as it’s sagging it’s pushing off the soil onto either side. To verify our conclusions we brought some Dutch engineers to come out and have a look and they agreed with us, that it looks like these walls are just sinking.

Q: Do these I-walls have to be replaced? Should all of these I walls be replaced?

A: Just as the corps has done in the Lower Ninth Ward, they’ve pulled out that whole I-wall section that led to the catastrophic flooding in the lower ninth and they’re replacing it with the inverted T-wall, with the batter piles, and sheet piles. That’s what we should have at the minimum, in any location where there is sheet piling and/or I-walls.

Q: Another thing the external panel raised was the idea of the storm that the corps looks at as tests of whether the system is strong enough. They said only looking at past storms isn’t enough, and that you have to look at future storms that could be even stronger than those we’ve had in the past, what are your thoughts on that?

A: An absolute must, what we’ve found in our research was the corps was using basically a 1959 definition of the hurricane. Even though the national weather service upgraded the standard that the corps was supposed to go by, in 1979 a cat 4 storm with 140 mile an hour winds, the corps stayed with the original definition. We can’t do that, we’ve got to recognize that we’re entering a period of a lot more larger storms, that big storms are part of the picture. If you look at the tracks in the last 50 years, a major hurricane has come very close to New Orleans about once every seven years.”