Because, like Venice (the Italian one, not the one in Los Angeles where I used to live), New Orleans is sinking.<\/p>\n
A 2001 Scientific American article<\/a> by Mark Franchetti suggested that the impact of a major hurricane on a city that has subsided 3 feet in the last 100 years would be catastrophic. The (pay-only) article opens:<\/p>\n THE BOXES are stacked eight feet high and line the walls of the large, windowless room. Inside them are new body bags, 10,000 in all. If a big, slow-moving hurricane crossed the Gulf of Mexico on the right track, it would drive a sea surge that would drown New Orleans under 20 feet of water. “As the water recedes,” says Walter Maestri, a local emergency management director, “we expect to find a lot of dead bodies.”<\/i><\/p><\/blockquote>\n New Orleans is a disaster waiting to happen. The city lies below sea level, in a bowl bordered by levees that fend off Lake Pontchartrain to the north and the Mississippi River to the south and west. And because of a damning confluence of factors, the city is sinking further, putting it at increasing flood risk after even minor storms.<\/i><\/p><\/blockquote>\n If Ivan hits New Orleans – or even comes close – the potential exists that New Orleans will be reshaped, and probably not in a good way.<\/p>\n The subsidence is caused primarily by compaction of the soft sediment the city is built on – like Venice – but in addition, as a center for oil and gas production, a substantial amount of the subsidence is caused by the simple extraction of the oil and gas which had been holding the city up.<\/p>\n Several proposals have been floated to inject water into the strata under the city, but these – like the gates being built to protect Venice<\/a> – are major and expensive infrastructure projects.<\/p>\n