In a yearlong review of levee work here, The Associated Press has tracked a pattern of public misperception, political jockeying and legal fighting, along with economic and engineering miscalculations since Katrina, that threaten to make New Orleans the scene of another devastating flood.
Dozens of interviews with engineers, historians, policymakers and flood zone residents confirmed many have not learned from public policy mistakes made after Hurricane Betsy in 1965, which set the stage for Katrina; many mistakes are being repeated.
"People forget, but they cannot afford to forget," said Windell Curole, a Louisiana hurricane and levee expert. "If you believe you can't flood, that's when you increase the risk of flooding. In New Orleans, I don't think they talk about the risk."
Tyrone Marshall, a 48-year-old bread vendor, is one person who doesn't believe he's going to flood again.
"They've heightened the levees. They're raised up. It makes me feel safe," he said as he toiled outside his home in hard-hit Gentilly, a formerly flooded property refashioned into a California-style bungalow.
Geneva Stanford, a 76-year-old health care worker, is a believer, too. She lives in a trim and tidy prefabricated house in the Lower 9th Ward, 200 feet from a rebuilt floodwall that Katrina broke.
"This wall here wasn't there when we had the flood," Stanford said, radiant in a bright kanga-style dress. "When I look at it now, I say maybe if we had had it up it there then, maybe we wouldn't have flooded."
They're not alone. A recent University of New Orleans survey of residents found concern about levee safety was dropping off the list of top worries, replaced by crime, incompetent leadership and corruption.
This sense of security, though, may be dangerously naive.
For the foreseeable future, New Orleans will be protected by levees unable to protect against another storm like Katrina.
When and if the Army Corps of Engineers finishes $14.8 billion in post-Katrina work, the city will have limited protection - what are defined as 100-year levees.
This does not mean they'd stand up to storms for a century. Under the 100-year standard, in fact, experts say that every house being rebuilt in New Orleans has a 26 percent chance of being flooded again over a 30-year mortgage; and every child born in New Orleans would have nearly a 60 percent chance of seeing a major flood in his or her life.
"It's not exactly great protection," said John Barry, the author of "Rising Tide," a book New Orleans college students read to learn about the corps' efforts to tame the Mississippi.
As a rule, any levee building makes people feel good in this unsettling landscape where the Gulf of Mexico can be seen gleaming from the top floors of skyscrapers and where the ubiquitous dynamics of a sinking and eroding river delta ripple through every aspect of life.
Levees tend to get built after devastating hurricanes: It's happening now and it happened after Betsy struck and flooded much of the same low ground that Katrina invaded.
"We did go in and did a whole bunch of levee work right after Betsy," said Philip Ciaccio, a New Orleans appellate judge and longtime former politician from eastern New Orleans, a reclaimed swamp transformed into the Big Easy's version of the American suburban dream.
Between Betsy and Katrina, about 22,000 homes were constructed in eastern New Orleans out of an abundance of confidence.
"We were under the illusion that what we had done would prevent another Betsy from flooding the area," Ciaccio said. "Hopefully the experts know what they're doing this time."
The corps says its work is making the city safer, but there are serious doubts.
At every step in the scramble to correct the engineering breakdowns of Katrina, independent experts have questioned the ability of the corps, an agency that has accumulated ever more power over the fate of New Orleans, to do the right job.
On the road to recovery, the agency has installed faulty drainage pumps, used outdated measurements, issued incorrect data, unearthed critical flaws, made conflicting statements about flood risk and flunked reviews by the National Research Council.
At the same time, the corps has run into funding problems, lawsuits, a tangle of local interests and engineering difficulties
all of which has led to delays in getting the promised work done.
An initial September 2010 target to complete the $14.8 billion in post-Katrina work has slipped to mid-2011. Then last September, an Army audit found 84 percent of work behind schedule because of engineering complexities, environmental provisos and real estate transactions. The report added that costs would likely soar.
A more recent analysis shows the start of 84 of 156 projects was delayed - 15 of them by six months or more. Meanwhile, a critical analysis of what it would take to build even stronger protection - 500-year-type levees - was supposed to be done last December but remains unfinished.
Another opportunity for setbacks: The corps says it will need more than 100 million cubic yards of clay and dirt to build up levees - enough to fill the Louisiana Superdome 20 times.
Also on the corps' drawing board are gigantic pumps capable of pushing more than 20,000 cubic feet of water per second. For comparison, the biggest pumps in New Orleans move about 6,000 cfs every second and they're among the most impressive in the nation.
That's not all: The corps has awarded The Shaw Group a $695 million contract to build a massive barrier against storm surge in the Industrial Canal. It's touted as one of the biggest public works projects ever performed by the agency.