NEW ORLEANS -- Six inches.
After two years and more than a billion dollars spent by the Army Corps of Engineers to rebuild New Orleans' hurricane protection system, that is how much the water level is likely to be reduced if a big 1-in-100 flood hits Leah Pratcher's house in the Gentilly neighborhood.
Looking over the maps that showed other possible water levels around the city, Pratcher - who had 4 feet of water in her house after Hurricane Katrina - grew furious. By comparison, the wealthier neighborhood to the west, Lakeview, had its flooding risk reduced by nearly 5 1/2 feet.
"If I got my risk reduced by 5 feet 5 inches, I'd feel pretty safe," said Pratcher, who along with her husband, Henry, warily returned home from Baton Rouge. "Six inches is not going to help us out."
New Orleans was swamped by Hurricane Katrina; now it is awash in data, studied obsessively in homes all over town. And the simple message conveyed by that data is that while parts of the city are substantially safer, others have changed little. New Orleans remains a very risky place to live.
The flood system still provides much less protection than New Orleans needs, and the pre-Katrina patchwork of levees, floodwalls and gates that a Corps of Engineers investigation called "a system in name only" is still just that.
The corps has strengthened miles of floodwalls, but not always in places where people live. It has built up breached walls on the east side of one major canal, but left the west side, which stood up to Hurricane Katrina, lower and thus more vulnerable. It has not closed the canals that have often been described as funnels for floodwaters into the city.
And its most successful work, building enormous floodgates to cut off the finger-like canals that brought so much flooding into the city, had a divisive effect. The gates now protect prosperous neighborhoods like Lakeview, and though corps officials say there has been no favoritism, the effect has been to draw out old resentments and conspiracy theories in a city that never lacked for them.
"We have spent a lot of money and gotten some very good patches, but we're putting them on this decayed old quilt," said Robert G. Bea, a professor of engineering at the University of California at Berkeley, an author of an independent report on the levee failures. "We're still with this damned patchwork quilt."
As a result, the city still lacks a system that can stand up to that 1-in-100 storm, let alone one like Hurricane Katrina, which the corps calls a 1-in-396 storm. The work that could build the more robust system - originally estimated at $7 billion and now at least twice that - will not be completed until 2011 at the earliest, and experts agree that even that level of protection will be less than the city needs.
The corps is working on a two-year, $20 million study to find ways of providing even more protection, but it will not even be released until December.
Without a strong rampart of protection against storms, New Orleans will have a hard time persuading its far-flung residents and businesses to return and rebuild.
The corps has hardly been idle in the two years since the flooding. It quickly mobilized a force that grew to 3,300 workers in the New Orleans area, and its cranes and bulldozers belch exhaust at waterways all over town, installing walls of concrete, huge pumps and mounds of earthwork.
Ultimately, though, the corps was trying to patch a 350-mile system that was unfinished and vulnerable long before Hurricane Katrina, and the haphazard results are clear. It has repaired breaches on the east bank of a waterway called the Industrial Canal with 4,000 feet of well-armored floodwall to protect the devastated Lower 9th Ward, even though few people are living there and there is little evidence of the neighborhood's return.
Across the canal, however, the walls that stood up to the storm have not yet been raised, even though they protect an inhabited neighborhood. They remain at their pre-Katrina height, lower than the new wall and vulnerable to being overtopped. They have been strengthened against catastrophic failure if water flows over the top, but floodwaters would still flow into Gentilly.
Meanwhile, the Mississippi River Gulf Outlet, an old navigation channel that many scientists say destroyed wetlands and contributed to a funnel effect that increased the damage to the city, has yet to be sealed off. The corps has said that proposals from contractors for doing so are on their way, but that work, too, might not be complete before 2011.
Then there are the new pumps at the mouths of the city's main drainage canals, which will be turned on if the massive new floodgates have to be closed to keep out lake water in the face of a storm. Two reports said that the pumps, ordered in a rush of planning before the 2006 storm season, had been a troubled operation from the start, and that if a storm had hit in the first year after Katrina, severe flooding could have occurred.
Experts who have examined the situation since then say that things have improved, and the pumps are working as planned. But community activists say they suspect that the corps has not yet fully fixed the problems.
On a broader scale, the essential but daunting work of restoring the wetlands along the Gulf Coast, which can reduce the effect of storm surges, has yet to get under way in earnest.
Col. Jeffrey A. Bedey, commander of the corps' Hurricane Protection Office, acknowledged that the work has been piecemeal, because the scale of the project is enormous. The drive to provide protection against that 1-in-100 storm by 2011, Bedey said, is more thorough. He said maps that will predict the impact of that work, which could be published this month, "should show Upper Gentilly looking very good," and much of the rest of the city, too.
The analysis many people will have to make, he said, is "Am I really willing to take the risk between 2007 and 2011" that no big storm will overpower the work done so far?