The report also called for an overhaul of the agencies that oversee flood protection. It took aim at Congress for its piecemeal funding over the past 50 years, and at state and local levee authorities for failing to properly oversee maintenance of the levees.
"You tend to get what you pay for," Dave Rogers, a member of the team of academics who extensively studied the system, said during a news conference on Monday.
The study was performed by the Independent Levee Investigation Team, led by the University of California, Berkeley. The group has been highly critical of the U.S. Army Corps of Engineers, which was in charge of designing and building the complicated system.
The study released Monday said floods overwhelmed levees and flood walls, both on the fringes and inside the city. Breaches were caused by weak soil in the levees, poor engineering and breakdowns in sections where different types of flood protection meet. CBS News correspondent Byron Pitts reports that in several places along the 350-mile levee system, the Corps used cheap material — sand instead of clay. According to investigators, the foundation for the levee walls were in some places just 13 feet deep — they should have been 60.
Pitts reports the culture at the Corps of Engineers changed in the past 40 years. Budget cuts and infighting between local politicians led to deadly inefficiency.
"We took the engineering out of the Corps of Engineers, and that's in an attempt to become better, faster, cheaper project managers," said Bob Bea, a former engineer with the Corps who worked on the investigation team.
As CBS News' Steve Futtermann reports, the findings dispute most of the corps' preliminary findings about what caused the levee breaches, saying the investigators had made critical errors in their analysis, as the Los Angeles Times notes.
The Corps of Engineers has been working to repair and upgrade the levee system before the June 1 start of the hurricane season, which is predicted to be hectic and above-normal, possibly producing between four and six major hurricanes in the Atlantic Ocean and Gulf of Mexico. However, officials said part of the work will not be finished by then.
Raymond Seed, a member of the study team, said Monday that engineers must pay attention to other spots in the system that may fail if another hurricane hits New Orleans.
"The next weakest link is the one you have to be worried about," Seed said.
While the corps is trying to upgrade the levee system, it is installing huge flood gates at key points to prevent the type of Katrina-like storm surge that entered canals and overtopped and breached levees, leading to the flooding of 80 percent of New Orleans and of surrounding areas.
A wide range of design and construction defects in levees around New Orleans raise serious concerns about whether the system can withstand the pounding of another hurricane the size of Katrina, even after $3.1 billion in repairs are completed, the Los Angeles Times reports.
The newspaper reports that these findings — laid out in a 600-page report — undermine assurances by both the Bush administration and the Corps of Engineers that the federal levee repair program will provide a higher level of protection to New Orleans.
Meanwhile, for the next two days, the city will test new evacuation plans and emergency response strategies meant to prevent the widespread confusion, especially among the poor, that accompanied the approach of Hurricane Katrina last year.
As part of the tests, about 80 volunteers will board New Orleans buses on Tuesday and head to the city's convention center and train station as a mock Category 3 hurricane bears down on the state's Gulf Coast. The make-believe evacuees will then be tagged with wristbands for tracking.
In a real hurricane, the evacuees would be taken from New Orleans by bus or train to shelters first within the state and then elsewhere, depending on availability.
Mayor Ray Nagin's new evacuation plan was unveiled earlier this month. Last year, as Hurricane Katrina approached, thousands of the city's poor were left behind because they had no transportation, couldn't afford to leave or didn't know where to go.
More than 1,000 people in Louisiana were killed when flood walls failed and tens of thousands of residents were trapped in attics and stranded on rooftops.
"This is our first chance to walk through our plan," said Jerry Sneed, an official with the New Orleans Office of Homeland Security. "We've got some technology we're trying to use so we know who we're putting on the buses and where they're going."
City and state officials are still counting on most people to evacuate on their own. Last year, about a million people drove out of the New Orleans area before Katrina hit.
Nagin's plan for those without a way out calls for the use of airlines and trains to aid with the outbound flow, though details were still being worked out. Nagin and Gov. Kathleen Blanco will participate in the drills as will members of the National Guard.
Tuesday's exercise will involve mock evacuations of New Orleans and the state's largest trailer park for Katrina and Rita evacuees in Baker, La., a Baton Rouge suburb. About 1,500 displaced people live there.
Only volunteers will participate in the small-scale, mock evacuations in New Orleans and Baker.
On Wednesday, the drill is designed to test responders with mock reports of power outages, downed phone lines and fallen trees or other structures.
The Federal Emergency Management Agency and the Department of Homeland Security are sending staffers to New Orleans and Baton Rouge for both days of the exercise.
Given the ominous forecast for the 2006 hurricane season, both Blanco and Nagin have warned residents to expect to evacuate more frequently than in previous years. Nagin plans to order evacuations for hurricanes as weak as Category 2, or those with sustained winds of 96 mph or higher.
Katrina was a Category 3 storm. A Category 5 is the most severe, with sustained winds of more than 155 mph. Winds that powerful can blow away entire buildings and create tidal surges of more than 18 feet.