A wide range of design and construction defects in levees around New Orleans raise serious doubts that the system can withstand the pounding of another hurricane the size of Katrina, even after $3.1 billion in repairs are completed, a team of independent investigators led by UC Berkeley’s civil engineering school said Sunday.
The findings undermine assurances by the Bush administration and the Army Corps of Engineers that the federal levee repair program due to be completed in June will provide a higher level of protection to New Orleans, which sustained 1,293 deaths and more than $100 billion in property loss from Katrina.
The team’s 600-page report disputed most of the corps’ preliminary findings about what caused the levee breaches, saying the investigators had made critical errors in their analysis.
The mistakes raise concerns about whether the corps is competent to oversee public safety projects across the nation, said Raymond Seed, a UC Berkeley civil engineering professor who led the investigation, which the National Science Foundation sponsored shortly after Katrina struck.
“People think this is a New Orleans problem,” Seed said. “It is a national issue.”
The Berkeley team found that the defects that caused breaches during Katrina -- including thin layers of soil with the consistency of jelly and sections of levees built with crushed seashells -- had gone undetected and could be widespread.
“The rest of the system is unproven,” Seed said. “The entire system needs a serious reevaluation and study.”
Though the report questions the corps’ competence, Seed said that Congress needed to authorize a comprehensive evaluation of the system and that the corps should conduct it.
The team’s report makes 11 major recommendations, such as creating a national flood defense authority and increasing the corps’ technical strengths.
According to Seed, the corps’ formal investigation has missed critical evidence and has reached incorrect conclusions.
The corps “is conducting the most important engineering analysis in its history” in determining why storm walls and levees around New Orleans failed, Seed said, “and they got it wrong.”
“When the entire world is watching and a city has been destroyed, you want to get it right.”
A spokesman for the corps said that it could not comment on specific findings until it had a chance to examine the Berkeley report, but that the agency stands by the New Orleans levees and the work of its investigators.
“I don’t think there is any question that it will be a better levee system than before Katrina hit,” said Gene Pawlik, a spokesman at the corps’ headquarters in Washington.
“We have had folks walk every inch of those levees.”
Pawlik said the agency had “huge confidence” in the team of 150 investigators.
The corps’ “interagency performance evaluation task force” is conducting the official government investigation into the levee failures.
It is to deliver a 7,000-page report June 1, though it has disclosed many key findings in preliminary reports and statements.
The corps’ investigation is to be reviewed by the American Society of Civil Engineers and the National Research Council.
According to a written statement, the head of the corps’ task force, Ed Link, is “delighted to get any additional input from thoughtful teams and looks forward to being able to review what they have done.”
The Berkeley-led team has three dozen researchers, including experts from seven other universities -- among them Texas A&M; and the University of Missouri, Rolla -- and several private corporations.
Berkeley is widely regarded to be among the world’s top civil engineering schools.
The group looked at the corps’ internal culture and resources and asserts that the corps’ technical competence has been eroding since the 1970s because of congressional pressure to streamline its organization and reduce project costs.
Robert Bea, a Berkeley engineering professor who began his career at the corps and is a member of the National Academy of Engineering, said the corps had failed to recognize early warning signs that might have alerted it to levee problems before Katrina.
Responsibility for the failures, Bea said, extends well beyond the corps and includes many levee boards and other local political organizations.
A series of compromises resulted in substandard design and marginal quality in exchange for lower costs, Bea said.
“A culture of safety was replaced by a culture of efficiency,” said J. David Rogers, a geological engineering professor from the University of Missouri, Rolla.
The Berkeley report, which has hundreds of additional pages of appendices, examines eight specific places where levees had breaches.
In seven out of eight cases, the Berkeley team said, corps investigators erred in analyses.
The most notable involves the 17th Street levee, which has been at the center of Katrina investigations.
Rogers said the failure began in a 1- or 2-inch-thick layer of soft clay, with a consistency like warm jelly, about nine feet below the crown of the levee.
As water rose and penetrated the foundation of the storm wall, the thin layers provided no strength to withstand the pressure.
When the levee gave way, it slid backward 51 feet and took the storm wall on top for the ride.
The existence of the thin layer of clay was missed in 1981, when the corps began taking soil borings along the canal to design the wall.
And in the location where the wall breached last year, two of the five samples fell from the drilling rig because they were so weak. That, the Berkeley team said, should have been a red flag.
The corps’ investigators missed the existence of the material, saying the failure of the foundation occurred in a much deeper layer of soil.
The difference may seem academic, Seed said, but goes to the heart of whether the corps has the expertise to certify that the levee system is sound.
The failure could have been prevented with larger earthen embankments, though they might have encroached into residential neighborhoods.
The higher cost would have paled against the damage caused by the failed levee, Seed said.
Meanwhile, on the Industrial Canal, the corps’ investigators said breaches that flooded the Lower 9th Ward were caused by high waters that went over the storm walls and eroded the foundation.
Seed said the evidence pointed the investigators in the wrong direction, like a butler at a murder scene holding a knife.
In fact, Seed said, the storm wall was undermined by water that had penetrated the foundation and weakened it.
The corps has said the Katrina storm surge went over the tops of miles of levees on the metropolitan region’s eastern flank.
The Berkeley analysis, Seed said, is that waves eroded the front side of the levees even before the surge reached the tops. The report said levees were constructed of weak materials, consisting of old seashells dredged from a shipping channel adjacent to the levees.
The failure points to the need to reinforce the front sides of the levees with materials strong enough to resist wave action and scouring typical of hurricanes.
Since Katrina, the corps has planned to install gates at the mouths of three canals that were responsible for 80% of the flooding in the city, saying that would eliminate any concern about future breaches.
But the weaknesses uncovered by the Berkeley team raise new concerns.
During future storms, the water levels in those canals will rise during pumping operations. If the canals and pumping stations are restricted to pumping less water because of weaknesses in the levees, the city will be more vulnerable to periodic flooding from rainfall.
New Orleans ranks near the top of U.S. cities in terms of annual rainfall, even without hurricanes.
A corps spokesman said the issue of allowable water levels in the canals was still being discussed.
The Berkeley investigators are to brief New Orleans leaders this morning and the Louisiana Legislature this afternoon.