http://www.telegraph.co.uk/news/m...xnews.html

Parts of New Orleans are sinking much faster than expected and the homes destroyed by Hurricane Katrina should never be rebuilt, scientists said yesterday.

They said that up to a fifth of the city was sinking into the Mississippi swamp by as much as an inch a year. Rebuilding would create "death traps" should another hurricane strike.

Geological research by a University of Miami team, published in the journal Nature, was produced using satellite data recorded in the three years before Katrina struck last year. It had long been thought that New Orleans was slowly submerging at only a fifth of an inch a year.

The research helps to explain why, when the floodwaters struck, the levees gave way: they were much lower than previously thought. They were also flimsily rooted in the city's shifting porous soil.

Thousands of tons of Mississippi mud, much stronger than Louisiana soil, have been imported to shore up the levees for the new hurricane season, which began yesterday. Seventeen named storms are forecast, only marginally down on last year's record 20.

"The very low-lying areas are death traps," said Tim Dixon, the principal author of the report. "I don't think those areas should be rebuilt."

The report attributes the increasing subsidence to over-development, excess drainage and seismic shifts.