Even before work could begin on repairing the damage caused by Katrina in New Orleans a year ago today, authorities first had to get rid of the murky and toxic water that in some places stood 14 feet deep.
After repairing damaged pump stations, it took 53 days to drain away more than 250 billion gallons. Since then the US Corps of Engineers have spent $352m (£186m) scrambling to repair some 220 miles of flood walls around the city and upgrade pumping stations.
Leaders of the corps can now assure residents that the levees today at least offer the same level of protection as before Katrina.
"I think we're in good shape," Don Powell, the Bush administration's co-ordinator of Gulf Coast rebuilding, said over the weekend. "There's no question in my mind, we're ready."
After last year's disaster, however, no one can pretend today that the old standards of the levees will be enough to protect the Big Easy against future big storms, and the process of rethinking and building up the system further has barely got under way. Indeed, damaging as it was, Katrina had actually eased to a Category 1 or 2 hurricane by the time it struck New Orleans.
The politicians in Washington, after initially lagging in their response to the post-Katrina crisis, have at least done their part. Roughly $5.7bn has now been appropriated for the reinforcing of the city's flood barriers. There is still no complete blueprint for the improvements, however, and nor have any contracts been awarded.
Under the terms of the financial assistance promised by Congress, the corps is obliged to build a system that will protect New Orleans against a one-in-100-year storm, of a type even more powerful than Katrina. It has until 2010 to complete the task.
Agreeing on achieving a 100-year standard was a milestone in itself, because it allowed the federal insurance programme to ease requirements on former residents to return to New Orleans and rebuild their homes.
The agreement meant thousands were spared from being forced to raise their houses on stilts.
Unresolved, meanwhile, is the extent to which the city and its neighbourhoods will be rebuilt as they were before last August.
Ray Nagin, the recently elected mayor, has backed away from proposals to shrink the city's footprint.
To do so would inevitably imply abandoning areas that are low-lying and which were disproportionately populated by poor blacks.
But it is predominantly those districts that today remain largely abandoned and forlorn.