The first section to reopen to residents will be Algiers, across the Mississippi River from the French Quarter, on Monday, Nagin said, according to the Associated Press. The city's Uptown section, which includes Tulane University and the Garden District, will be reopened in stages next Wednesday and next Friday, he said. The French Quarter will follow on Sept. 26.
"The French Quarter is high and dry, and we feel as though it has good electricity capabilities," the mayor said, "but since it's so historic, we want to double- and triple-check before we fire up all electricity in there to make sure that, because every building is so close, that if a fire breaks out, we won't lose a significant amount of what we cherish in this city."
The reopened areas represent about 182,000 residents, he said.
Government tests show the floodwaters still contain dangerous bacteria and chemicals, but the air is now safe to breathe.
The New Orleans suburbs of Gretna, Westwego and Lafitte in Jefferson Parish started allowing residents to return to inspect their damaged homes on Wednesday.
President Bush, meanwhile, is scheduled to make his fourth trip to the region to deliver a prime-time address on the short-term and long-term recovery and rebuilding plans for New Orleans and other areas hit by Hurricane Katrina.
The address comes as the death toll in Louisiana grew to 474 and was expected to rise as state and federal officials continued the grim tasks of collecting bodies and identifying them through DNA tests.
The state attorney general on Tuesday filed negligent homicide charges against the operators of a nursing home, St. Rita's in St. Bernard Parish, where 34 residents drowned. A state investigation was also launched at another nursing home in New Orleans, where 14 patients died as they awaited rescue.
The total death toll for the Gulf Coast region has hit 710 -- mostly in Louisiana and Mississippi, and some in Florida, Georgia and Alabama, reported the AP.
About 319,000 homes and businesses in Louisiana -- about 29 percent -- remain without power, while Mississippi has about 84,000 customers without service, according to Reuters.
In Washington, hearings began Thursday in the Senate on the local, state and federal response to Hurricane Katrina, which has been widely criticized as being too slow.
The Aug. 29 hurricane has caused governments at all levels to reassess their emergency response plans.
"Everything that we planned basically made the assumption that if we get people to high ground and get as many people out of the city as possible, then within three days, if we're totally flooded, then the calvary would come," said Nagin, according to CNN. "I am not going to plan in the future for the calvary to come in three days."
Louisiana Gov. Kathleen Blanco pledged Wednesday to rebuild New Orleans and other damaged areas of her state to allow more than 1 million displaced residents to return home, reported CNN.
She said she wanted "the world to know what we know -- we are brave, we are resilient and we will prevail."