Levees' Construction Faulted In New Orleans Flood Inquiry
Thursday, November 3, 2005
Investigators yesterday added a possible new explanation for some of the flooding that devastated New Orleans after Hurricane Katrina: contractors who may have skimped on construction materials in building the city's floodwalls and levees.
Experts probing the cause of the flooding have received at least a dozen allegations of major cheating by builders and possibly others involved in levee construction, two investigators said in testimony before a Senate panel. They said these were potentially criminal acts that may well have contributed to the collapse of the city's flood-control system on Aug. 29.
The allegations, although not proved, have prompted investigators to request a meeting next week with federal law enforcement officials to share details of the reports.
The list of alleged misdeeds includes the use of weak, poorly compacted soils in levee construction and deliberate skimping on steel pilings used to anchor floodwalls to the ground.
"What we have right now are stories of malfeasance and some field evidence that seems to correlate with those stories," said Raymond B. Seed, leader of one of three independent teams of experts investigating why the levees failed. Seed, an engineering professor at the University of California at Berkeley, said it is not yet clear how big a role such acts played in the failure of the levees.
The reports emerged from one of two Senate hearings held yesterday to examine why New Orleans's levee system failed so spectacularly, and how it might be rebuilt to prevent catastrophic flooding by the next hurricane.
New Orleans Mayor C. Ray Nagin asked President Bush and Congress to commit the nation to rebuilding his city's levee system to withstand a Category 5 hurricane, calling it necessary to win back workers and businesses. The existing 200-mile system was designed to withstand a Category 3 storm.
"We can do much better. We definitely can build to a world-class standard that we don't have today," said Nagin, citing storm barrier systems in the Netherlands, United Kingdom and Italy.
Most of the devastation caused by Katrina was inflicted not by high winds, but by massive flooding that resulted when the city's levees breached. Four major breaches and dozens of smaller ones occurred on the morning of Aug. 29, sending water surging across 80 percent of New Orleans and swamping an estimated 100,000 homes. About 1,000 people died.
The levees were designed by the U.S. Army Corps of Engineers and were built primarily by contractors hired by the Corps. The Corps has launched its own investigation of the levee failures; Paul Mlakar, a Corps scientist leading the inquiry, said though it is too early to draw firm conclusions, he promised a thorough investigation, with final results in July. The Corps is also cooperating with the independent investigations by the state of Louisiana, the American Society of Civil Engineers, and the University of California team, which is funded by the National Science Foundation.
Leaders of the three teams yesterday presented preliminary findings of their two-month probe to the Senate Homeland Security and Governmental Affairs Committee. In recent weeks, findings by the independent investigators have pointed increasingly to human error -- flaws in design, construction, or both -- as a probable culprit in the breaches of two key floodwalls along Lake Pontchartrain.
Although Army Corps officials initially suggested that the 17th Street and London Avenue canals were simply overwhelmed by Katrina's storm surge, the new findings confirmed that the two floodwalls were never overtopped by rising waters. Instead, the concrete walls toppled when their earthen foundations weakened and gave way.