Sinking feeling for real in New Orleans

AP/Washington Post:

Everyone has known New Orleans is a sinking city. Now new research suggests parts of the city are sinking even faster than many scientists imagined _ more than an inch a year.

That may explain some of the levee failures during Hurricane Katrina and it raises more worries about the future.

The research, reported in the journal Nature, is based on new satellite radar data for the three years before Katrina struck in 2005. The data show that some areas are sinking four or five times faster than the rest of the city. And that, experts say, can be deadly.

"My concern is the very low-lying areas," said lead author Tim Dixon, a University of Miami geophysicist. "I think those areas are death traps. I don't think those areas should be rebuilt."

The blame for this phenomenon, called subsidence, includes overdevelopment, drainage and natural seismic shifts.

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Texas actually has subsidence districts to manage it. Most of it was caused by the extraction of ground water. This led to the building of several surface water reservoirs north of the Houston area. With New Orleans' reduced population, they should be using much less water, and I think they take a good bit of their water from the Mississippi River. Some fo the residence joke about drinking water that has been flushed by few thousand miles of toilets.