Unit 3 New orleans is sinkingFor 300 years, the sea has been closing in on New Orleans. As the coastal erosion continues, it is estimated the city will be off shore in 90 years. Even in good weather, New Orleans is sinking. As the city begins what is likely to be the biggest demolition project in U.S. history, the question is, can we or should we put New Orleans back together again?Life has been returning to high and dry land on Bourbon Street, but to find the monumental challenge facing the city you have to visit neighborhoods you have never heard of. On Lizardi Street,60 Minutestook a walk with the men in charge of finishing what Katrina started.Correspondent Scott Pelleyreports.Before Katrina, There would be noise and activity and families and people, and children, and, you know, I havent seen a child in a month here, says Greg Meffert, a city official who, with his colleague Mike Centineo, is trying to figure out how much of the city will have to be demolished.Meffert, who is in charge of city planning, says it is very possible up to 50,000 houses will have to be bulldozed. Right now, most of the homes in the city are uninhabitable.Meffert faces a difficult task. Every time he goes to a house site here, he says, Its one more knife in me that says, She did another one. She did another one, explains Meffert, she meaning Hurricane Katrina.When you walk through these neighborhoods and you see the houses, you get a sense of the pain of the individual families. But you dont get a sense of what has happened to the city of New Orleans itself.It is estimated that there were 200,000 homes in New Orleans, and 120,000 of them were damaged by the flood.The part of the city known as the lower Ninth Ward received some of the heaviest flooding. The houses are splintered block after block after block, almost as if the city had been carpet-bombed in war.Meffert says that before the storm, New Orleans had a population of 470,000-480,000 people. Realistically, he thinks that half of those residents wont be coming back.The possessions of thousands of families, the stuff collected over lifetimes is suddenly garbage, clawed up into mountains in city parks. With so much gone already, should New Orleans pick up right where it was?We should be thinking about a gradual pullout of New Orleans, and starting to rebuild peoples homes, businesses and industry in places that can last more than 80 years, says Tim Kusky, a professor of earth sciences at St. Louis University.Kusky talks about a withdrawal of the city and explains that coastal erosion was thrown into fast forward by Katrina. He says by 2095, the coastline will pass the city and New Orleans will be what he calls a fish bowl.Because New Orleans is going to be 15 to 18 feet below sea level, sitting off the coast of North America surrounded by a 50- to 100-foot-tall levee system to protect the city, explains Kusky.He says the city will be completely surrounded by the Gulf of Mexico just 90 years from now.Since this story aired on Nov. 20, there has been considerable discussion about whether New Orleans really is sinking, including onCBS News blog, Public Eye.Thats the projection, because we are losing land on the Mississippi Delta at a rate of 25 to 30 square miles per year. Thats two acres per hour that are sinking below sea level, says Kusky.That process could only be slowed, in theory, by massive restoration of wetlands. In the meantime, while Kuskys advice is to head for the hills, some New Orleans residents are hoping to head home.Vera Fulton has lived most of her 81 years on Lizardi Street and returned to her home recently for the first time since being evacuated.When they say storm, I leave. I cant swim and I cant drink it. So what I do, I leave, says Vera, who has lost her home to two hurricanes.Vera is intent on coming back. I dont have no other home, where Im going?Three generations of Fultons, Veras son Irvin Jr., his wife Gay and their son Irvin, 3rd, live around Lizardi Street.Irvin says his house is just flat and he didnt have insurance.Thats the dilemma. The only thing they have left is land prone to disaster. They want to rebuild, and the city plans to let them.At Veras house, Mike Centenio, the citys top building official, told60 Minuteshomes can go up as long as they meet what is called the 100-year flood level.The federal government had set a flood-level, but didnt figure on a levee failure that would flood parts of the city.The official level is several feet off the ground. If people meet the requirement, they can rebuild their homes, despite the fact that we saw, for example, a refrigerator lifted to the top of a carport by the floodwaters.Asked whether allowing people to rebuild makes sense, Centenio says it is going to take some studying.Right now, he says the flood leve