Thursday, May 31, 2007

New Orleans, Subsidence, Flooding and Global Warming

Here is a better solution (see the picture below) for rebuilding New Orleans. The city is built on a major river delta, (The Mississippi). River water slows down as it enters a standing body of water, (The Gulf of Mexico). When the flow of water decreases, the sediment, (clay, sand, and gravel) it is carrying is dropped, and deposited as sediment, forming a delta. Over time the sediment compacts as water is squeezed out. The compaction results in subsidence or settling of the land surface. Thus if you build on a delta, what you put there is going to sink.

New Orleans has been subsiding since the day it was founded. Geologists and engineers have known this for a long, long time. Most of the city is below sea level, and has been for a long time. Water flows downhill. Levees of any kind are only a temporary fix. Is it worth the money to build the levees higher, or the buildings higher, and maintain them forever? That is the question, because the flooding will happen again, and again, and again, global warming, or Al Gore, Democrats or Republicans, or not.

Man has tried to thwart nature, by building levees and straightening the Mississippi. Somehow, man always gets it wrong and nature does what it, (she) wants to. Rivers go where they want to go, (downhill, and to the lowest point), and our climate will change, as it always has. (Build your beachfront homes on stilts). Earthquakes will happen, (don't build on known active fault lines), and hurricanes, local flooding and tornadoes will always happen.


(satellite photo of the Mississippi River Delta, showing how it's sediments are spread farther out into the Gulf of Mexico, letting New Orleans subside, sink, and flood.........Peter's opinion)

And I love New Orleans, its history, music, cuisine, culture.....

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