November 3, 2005

Katrina Levee failure post-mortem

The post-mortem on the failed Levee's in New Orleans is starting and some suspicions are starting to pan out. From NOLA.COM:
Levee materials, techniques questioned
Possible malfeasance on project, reports to engineers indicate

Engineers looking into failures in the New Orleans levee system say they have received reports of possible malfeasance in construction of canal floodwalls that failed during Hurricane Katrina and believe more investigation is needed.

Ray Seed, a professor of engineering at the University of California at Berkeley who is heading a National Science Foundation probe, told a hearing of the Senate Homeland Security Committee on Wednesday that people involved in building the levees had approached investigators with stories of contractors using substandard practices and building materials -- some in breached areas, some elsewhere.

Seed cautioned that it's too early to tell whether the reports will pan out, or whether they will ultimately be linked to the breaches in the 17th Street and London Avenue canal floodwalls that allowed water to pour into much of the city after Katrina. "We don't want to alarm people because some of those stories probably won't hold up," he said.

After the hearing Seed said the engineers are "hearing from people who were involved and now feel very badly and want to try and make it right, because now they understand that it was dangerous. We're hearing from widows of people like that. We're hearing it from a variety of sources right now, and what makes us nervous is we're hearing some stories repeated from different sources."

Investigators have concluded that Katrina's storm surge in Lake Pontchartrain did not top floodwalls in the 17th Street and London Avenue canals, which were breached in three places. That suggests human error may be to blame.

Allegations of flaws

The walls may have had design flaws, particularly in their sheet pile foundations, which engineers say were too short to anchor the walls and prevent storm surge from seeping underneath. After Katrina's surge rose to 10 or 11 feet in the canals, soft soil beneath walls in two areas moved and the walls failed, according to a preliminary report released Wednesday by engineering teams for the National Science Foundation and the American Society of Civil Engineers.

Seed said some of the reports of construction irregularities correlate with what investigating engineers have observed on the ground and should be thoroughly investigated.

"Examples of allegations would be sheet piling being less perhaps than was called for, or embankment materials that were supposed to be imported as a relatively dry and compactable fill being instead brought in wet from a swamp and not being compactable," Seed said. "Things that would save significant time and money and certainly be expedient, but things that would not necessarily foment improved safety."

The breached 17th Street Canal floodwall was built in 1993 by Pittman Construction, a firm that no longer exists. It is not clear which company built the London Avenue canal walls.
Emphasis mine -- got to love that quote: "things that would not necessarily foment improved safety" The article goes into some more detail about things that have been found already. Add to this the fact that multiple agencies were in charge of different levee's and you have a recipe for failure. Posted by DaveH at November 3, 2005 11:42 PM | TrackBack
Comments
Post a comment









Remember personal info?