Why did the floodwalls break and not the levees?
Tags: floodwalls, levees, ivor van heerden, lake pontchartrain, engineeringFrom this:
One of the central mysteries emerging in the Hurricane Katrina disaster is why concrete floodwalls in three canals breached during the storm, causing much of the catastrophic flooding, while earthen hurricane levees surrounding the city remained intact…
"Why did we have no hurricane levee failures but five separate places with floodwall failures?" asked Joseph Suhayda, a retired LSU coastal engineer who examined the breaches last week. "That suggests there may be something about floodwalls that makes them more susceptible to failure. Did (the storm) exceed design conditions? What were the conditions? What about the construction?"
Ivor Van Heerden, who uses computer models to study storm-surge dynamics for the LSU Hurricane Center, has said that fragmentary initial data indicate that Katrina's storm-surge heights in Lake Pontchartrain would not have been high enough to top the canal walls and that a "catastrophic structural failure" occurred in the floodwalls…
