Can we raise New Orleans above sea level?

We all know that New Orleans is particularly vulnerable to flooding, since 80% of the city lies several feet below sea level – a problem that was tragically brought home in the wake of Katrina and Rita. Most of the flooded areas are so badly damaged, they will have to be bulldozed and rebuilt from scratch.

So…now that we have the opportunity, why not raise the city above sea level? About 20 feet of rocks and dirt piled on the devastated areas ought to do it. Sure, it’ll be a mammoth project, but we have the money and technology. There’s a whole bunch of mountains in the Rockies and Appalacians we don’t need, just tear down a couple and truck 'em to N’awlins. Countries in the Far East do this all the time to build airports in the middle of the ocean.

Any reason this couldn’t be done?

There isn’t really “bedrock” per se below the city so these raised areas too will sink into the ground and eventually be below sea-level.

No worries, we could create our own artificial bedrock with nuclear power: Why not jack up New Orleans? :wink:

Well, they did do it in Galveston after the hurricane of 1900. It’s worked pretty well ever since, but personally I’d have moved the hell away from Galveston myself.

Galveston is a barrier island with sandy soil. While raising the city took about 20 years and almost bankrupted the city in the early 1900s, at least the underlying soil is relatively stable.

New Orleans is built on river delta silt which is slowly settling and sliding into the Gulf of Mexico. Even if they built the city up at phenomenal expense, it would not be a permanent solution.

Because of this, the two situations are unfortunately not comparable.

But isn’t New Orleans already sinking an inch every year?

Temporary or no, twenty feet of dirt will at least keep the city dry for another hundred years, until another more permanent solution comes along.

Do you have any idea of the magnitude of work involved in raising the entire city of New Orleans by anything in the realm of 20 feet?!

In any event, the city is not subsiding anywhere near that much. The average subsidence rate for the past 50 years has been about 2 inches per decade. Some spots subside faster than this. They project about 1 meter of subsidence over the next century. However, sea levels are also rising.

Source:

The fundamental problem is that the subsidence will never stop (in human time frames, anyway). The sediment the city sits on is over a thousand feet thick, and was laid down over thousands of years.

The City of New Orleans could do what the Dutch did after The Great Flood of 1953:

http://en.wikipedia.org/wiki/Delta_Works

But given our current president, I don’t know if the Feds will send that much money to actually do something productive to keep stuff like this from happening in the future…

Ah, no; the city probably ought to be content with shrinking down to the old quarter (more or less; there are lot of safe area outside of it, but they are not always contiguous). And moving people to a better, drier location further inland. You don’t need the whole city there for the docks. And the river probably ought to be moved westward anyway; it would have moved there long ago if not for the Army Corp of Engineers.

NICELY done. I wonder how many Dopers noticed that you rendered the correct term for Vieux Carré. So many folk think it means “The French Quarter.”

Sorry for going off-topic, but nicely done.

Rethinking my last post…probably a lot of you. This ain’t your typical board. Sorry.

How about this: Instead of trying to raise Nawlin’s via the use of concrete, the odd mountain, or what have you, we put it on floats instead? That way it won’t matter how much the ground underneath it sinks or how much the sea levels rise. (It’s just too bad Clinton wasn’t in office to give a speech about rebuilding the city, because at least he would have pointed out that we can’t allow the “Party Capital of the US” to languish.)

There’s also the Old Man River City option.

Instead of raising the city, wouldn’t it be easier to turn the city into an American version of Venice?

Both the “floating city” and “venice” options could be done. it would be expensive, but probably affordable option and culd give some amazing scientific and engineering opportunities.

A mixture of both might work. We can, of course, just rebuild some small acess roads to wind through the stable portions, and float the rest. Hmm… I’ll need to determine the wight-load of a heavy two-story house. Could it be done with some sort of thick plastic float? Anchored to the bed and to other surrounding houses? That’d keep it stable enough.

Thank you very much, but I can claim little credit. I’m not too well-read on New Orleans; I was under the impression that the proper name nowadays was the French Quarter. But of course, it is also old quarter of the city. Not having been there, I assumed that was what appeared on signs and things.

Why not simply use concrete floats as has been done on some bridges? That way if there was a fire, you wouldn’t have to worry about the the floats catching fire or melting?

You want us to… fill it with Italians? :confused:

Here’s my lighthearted suggestion: Anchor the entire city to hot air baloons and airships overhead. Finance the airships by offering tourists the chance to go up and take a look at the city, or maybe dine while looking down on the Old Quarter. :smiley: