By ERIC BERGER
Copyright 2001 Houston Chronicle Science Writer
"Any significant water that comes into this city is a dangerous threat," Walter Maestri, Jefferson Parish emergency management director, told Scientific American for an October article.
"Even though I have to plan for it, I don't even want to think about the loss of life a huge hurricane would cause."
New Orleans is essentially a bowl ringed by levees that protect the city from the Mississippi River to its south and Lake Pontchartrain to the north. The bottom of the bowl is 14 feet below sea level, and efforts to keep it dry are only digging a deeper hole.
During routine rainfalls the city's dozens of pumps push water uphill into the lake. This, in turn, draws water from the ground, further drying the ground and sinking it deeper, a problem known as subsidence.
This problem also faces Houston as water wells have sucked the ground dry. Houston's solution is a plan to convert to surface drinking water. For New Orleans, eliminating pumping during a rainfall is not an option, so the city continues to sink.
A big storm, scientists said, would likely block four of five evacuation routes long before it hit. Those left behind would have no power or transportation, and little food or medicine, and no prospects for a return to normal any time soon.
"The bowl would be full," Levitan said. "There's simply no place for the water to drain."
Estimates for pumping the city dry after a huge storm vary from six to 16 weeks. Hundreds of thousands would be homeless, their residences destroyed.
The only solution, scientists, politicians and other Louisiana officials agree, is to take large-scale steps to minimize the risks, such as rebuilding the protective delta.
Every two miles of marsh between New Orleans and the Gulf reduces a storm surge -- which in some cases is 20 feet or higher -- by half a foot.
http://www.hurricane.lsu.edu/_in_the_news/houston.htm
