Reconstruction: Engineers in New Orleans face an unprecedented rebuilding programme as operations to pump water out of the flooded city began yesterday. Flood levels in some areas were said to have dropped by a foot after army engineers plugged a major gap in the levees.
It emerged yesterday that many of the roads, sewers and pipes carrying water and gas will have to be replaced, and that contamination by sewage and toxic chemicals could mean some areas have to be rebuilt completely.
Hugh Kaufman, senior policy analyst for emergency response at the Environmental Protection Agency, said New Orleans may need one of the largest public building programmes ever seen in the US, which could be as costly as the war in Iraq.
"You have to repair and rebuild the sewage treatment plant and sewer infrastructure, as well as the drinking water infrastructure," he said.
"You're talking about a massive public works programme of rebuilding that I don't think we've seen in this country before. We're talking about like how much money we're putting into Iraq," said Mr Kaufman, who worked on the clean-up of New York after 9/11.
"You have a large amount of hazardous materials. Industrial discharges to the sewers have now been released. Sewage that would go into the sewers and into waste-water treatment plants, all of that is being released.
"You have oil and gas from gasoline stations, and waste oils that have been released. You've got household hazardous materials, you've got pesticides, you've got chemicals," he said.
Gordon Masterton, of the British Institution of Civil Engineers, said: "I'm very pessimistic. The ground below New Orleans is very absorbent, like a sponge, and soaked in water that sponge will have swelled up in uneven ways. When they pump the water out again the sponge will contract, so there'll be quite a lot of movement in road surfaces, water pipes, gas pipes and sewer pipes. I would expect quite a lot of damage to those."
Lieut Gen Carl Strock, commander of the Army Corps of Engineers, said one of the two major breaches in the city's levee system had been plugged and the other should be fixed later today.
"Once we seal those two places, that should stop the water from going in," he said. "Our real focus right now is getting the flow stopped so we can get in and drain the city."
Telephone company BellSouth Corp estimated it would cost $400-$600 million and take up to six months to repair the damage in the hardest-hit areas of New Orleans and the Gulf Coast.
Reconnecting the electricity presents one of the greatest headaches. Entergy, the New Orleans utility company, yesterday said technicians still could not get near equipment to determine its status. It said its underground system was designed to survive submerging but, above ground, equipment such as electronic controls and transformers had been damaged.
Every building would have to be checked before the electricity was brought back on.
Experts said some buildings may be so heavily contaminated with sewage and toxic chemicals that it might be necessary to rebuild much of the city.
"The toxic soup is touching every square inch of the flooded areas," said Paul Farmer, director of the American Planning Association. "The environmental clean-up is one that we have not faced with other disasters.
"It's not just the structural integrity of the buildings, but it's the whole issue of contamination: contamination of buildings, contamination of yards," he said.
There are 22 large-scale pumps used by city engineers to keep the streets of the low-lying city dry when it rains. They could be used in the operation once enough water has been removed and their electrics replaced.
Modern concrete and steel offices should survive relatively unscathed, though smaller-scale buildings, such as houses, may have to be rebuilt as the sodden ground makes them liable to subsidence.