In The Category Of You Heard It Here First

I have been writing about the failure to maintain, improve and redesign our own infrastructure for years. In the process I have been criticized by friends, colleagues and external commentators that the Army Corps of Engineers monitors these things and keeps everything working, especially when it comes to major bridges, levees, locks, piers and breaker walls. It just hasn't been so...

Army Corps Is Faulted on New Orleans Levees: Panel Says Studies Foresaw Failure, Urges New Scrutiny

An organization of civil engineers yesterday questioned the soundness of large portions of New Orleans's levee system, warning that the city's federally designed flood walls were not built to standards stringent enough to protect a large city.

The group faulted the agency responsible for the levees, the Army Corps of Engineers, for adopting safety standards that were "too close to the margin" to protect human life. It also called for an urgent reexamination of the entire levee system, saying there are no assurances that the miles of concrete "I-walls" in New Orleans will hold up against even a moderate hurricane.

"The ability of any I-wall in New Orleans to withstand . . . is unknown," said the American Society of Civil Engineers' External Review Panel, which was appointed to oversee the Corps investigation of the levee system's collapse during Hurricane Katrina.

The civil engineers group also rejected the explanation given by the Corps that the system had failed because Katrina had unleashed "unforeseeable" physical forces that weakened the flood walls. In a letter to Lt. Gen. Carl A. Strock, the Corps' commander, the civil engineers cited three previous Corps studies that predicted precisely the chain of events that caused the city's 17th Street Canal flood wall to fail. The breach left much of central and downtown New Orleans underwater.

"It appears that this information never triggered an assessment . . . neither at the time of the design of the 17th Street Canal flood wall, nor following its construction," the letter said.

Corps officials said they had already taken steps to address problems identified in the letter, starting with an effort to replace miles of I-walls with sturdier structures. But agency officials insisted the Corps was not solely to blame for weaknesses in the system.

"We have done the best things we could have done. We live here," spokeswoman Susan J. Jackson said. During four decades of levee-building in New Orleans, Jackson said, the agency frequently found its hands tied because of restrictions imposed by budgets, by Congress or by local governments that often failed to meet financial responsibilities to help build and maintain the levees. Jackson added: "It was a question of who was going to pay, and how much."

The American Society of Civil Engineers panel is one of three independent teams investigating the failure of the New Orleans levees, and until now it has been the most cautious in its public criticisms. The other investigating teams quickly endorsed its findings.

"We agree that every single foot of the I-walls is suspect," said Ivor van Heerden, leader of a Louisiana-appointed team of engineers. "When asked, we have constantly urged anyone returning to New Orleans to exercise caution, because the system now in place could fail in a Category 2 storm. It has already failed during a fast-moving Category 3 storm that missed New Orleans by 30 miles."

Two weeks ago, the Corps proposed a new theory for why the 17th Street Canal flood wall collapsed on Aug. 29, despite never being overtopped by Katrina's floodwaters. Whereas previous investigations had pointed to weak soils beneath the flood wall, new data suggested a combination of factors: First, the force of rising floodwaters inside the canal bent the walls outward, creating a small gap between the walls and their earthen foundation. Then, water surged into the gap, pressing the walls further until they broke through a layer of weak soil piled up against the sides. In effect, the levee was sliced in half along its ridge.