Pumping, Riley said, is a question of having electric power. The Corps would provide two generators, he added, but he could not say when they would arrive. Entergy, the local power company, said its crews are working, but only in "accessible" areas, of which New Orleans had few -- because of the flooding.
Out-of-town energy officials said Entergy, even once it gets up to speed, is likely to find that redoing electric power after Katrina presents far different challenges from clean-up after the devastation of a normal here-today-gone-tomorrow hurricane.
"You can throw the conventional methods of restoration out the window," said Fred N. Day IV, chief executive of Progress Energy Carolinas, which battled severe flooding in eastern North Carolina after Hurricane Floyd in 1999. "Just to get people and materials in place was so difficult we had to use helicopters."
Then there were "unusual safety issues," like "snakes and dogs and wild animals that can't make it to higher ground," Day continued. "Our employees went to a local sports shop and bought all the hip boots and flat-bottomed boats there were. It worked out good."
Jeff Corbett, Progress's vice president for distribution, said cuts and bruises are dangerous. "We had to be sure that a little scratch wouldn't create life-threatening infection," Corbett said. "With the stagnant water and the chemicals and dead animals, it eventually becomes a nasty soup."
Day said Progress restored power to "those who could take service" in less than a week, but the rest -- about 20 percent -- were part of "a long drawn-out process," with contractors from sister utilities, including Progress, cycling in and out over months.
But a real estimate? "Our scale was big to us at the time," Day said. "But it was nothing compared to what they have in Louisiana."
Having electricity will also be critical to restoring drinking-water and wastewater treatment. L.D. McMullen, chief executive and general manager of the Des Moines Water Works, described a "three-step process" to restore his plant. It was submerged in 1993, when the Raccoon and Des Moines rivers overflowed their banks.
The key, he said, is to keep contaminated water out of the system. First clean the treatment plant, start it up and run it until it is making drinkable water -- at least seven days. Then flush the system, using extra chlorine and taking care to dump the water wherever you can.
Finally, McMullen said, individual families have to flush their lines. He suggested a vigorous media campaign and phone bank staffed with plumbers, "who did a superb job" helping instructions.
The whole exercise took 19 days in Des Moines, with 350,000 people and 1,000 miles of pipeline. "The general concept would work fine in New Orleans, but probably would take longer because it's a bigger system," McMullen said. "There's probably a lot of broken pipes in town and broken mains, too. You'd have to repair them first."
Deciding whether to repair, or simply abandon, damaged homes will require a complicated triage involving not only residents but also insurance companies and local officials who will set the rules on which houses will be allowed to stand and which will come down.
Floods Ravage New Orleans