Its a city, not a bunch of condominium lofts

So now they are talking about the rebuilding of New Orleans as though it was some kind of "warehouse condominium" project.
They think it will be like what happens when developers buy an old warehouse and renovate it into trendy loft condominiums. They think they can empty the city completely so it can be drained and cleaned up and rebuilt and then -- and only then-- will everybody be able to move back in.
This is about as realistic as the 3000 lb sandbag idea -- sounds a neat and simple solution in theory; totally unrealistic in practice.
So typical of the way rich people think -- people who would never dream of staying in their house during a major renovation, but instead would move to a hotel and only come back when everything is finished and cleaned up. In its breathtaking impracticality, of course, this idea is not dissimilar to many of the other ideas which have come out of the Bush administration -- these guys are famous for this faith-based thinking, that they can just wish for something and voila, it is done!
Give your heads a shake. Ain't gonna happen.
The reason is a plot point in all those great "end of the world" novels -- Lucifer's Hammer, and Warday, and Out of the Deeps, and No Blade of Grass. It happened in London during the Blitz. It happened in Paris in 1945, and in New York after 911.
People will not leave. People love their cities.
People in particular love New Orleans.
In checking that new blog I found yesterday, The Interdictor, this guy wants to stay:

Outpost Crystal is still secured and still kicking. We've got people begging us to leave, but that's not going to happen. We might lose Charlie Squad depending on internect connectivity, but Alpha Squad and Bravo Squad are going nowhere until New Orleans' infrastructure is rebuilt or declared permanently and irrevocably destroyed. As far as I'm concerned, this building is my post, and it will not be abandoned until I'm properly relieved.

And judging by the photos he has posted on his blog, the area of the city he lives in looks pretty normal -- needs a good cleanup, but it looks like any city would after a windstorm. Its messy but its not a disaster area, the streets are dry, the buildings look intact, windows not blown out. The photos show people bicycling by, the occasional car, and a fire truck coming past. The thousands of people who used to live in this area are going to want to come back as soon as they can -- they left all their stuff behind, and they will need it. So the good guys in New Orleans, many of them at least, won't want to leave.
The bad guys won't be leaving either. Where do they have to go? I cannot, offhand, think of any community anywhere which would welcome the armed bands of gangsters who now infest New Orleans.
In spite of the flooding and all the chaos, a few hundred or even a few thousand armed teenagers could survive in New Orleans indefinitely -- looting food from and staying in the thousands of intact houses and apartments like those of Interdictor's neighbourhood. When the police and everyone else is gone, they can loot the remaining drugstores and hospital pharmacies for any drugs they might want. And once the power and water are back on -- which they have to be, before rebuilding can occur -- why, then these guys are in clover. And they can, like the insurgents in Iraq, maintain their slacker's paradise by taking occasional potshots at any re-construction workers foolish enough to try to begin the reconstruction.
The National Guard and the army can waste a lot of manpower trying to clean out these people, likely with about the same degree of success as they have had cleaning insurgents out of Fallujah, driving them out of one area only to have them pop up somewhere else.
Its not a pleasant picture. Maybe if enough of the good guys stay, then the bad guys won't get such an upper hand.