Rebuilding NO, Part II: Commenters' Takes

My kinda dumb initial post unleashed a lot of intelligent stuff from the readers.

If you're interested in this, make sure you read all the comments. Well, not Cedarford's rant about "a city run by blacks too incompetent" to evacuate.

First of all, Whitehall notes that bringing up the grade of the whole city, or the bulk of it, would take a hell of a lot of dirt:

If 80% of the city was flooded from a Cat 4 (maybe Cat 3+), to say an average depth of 4 feet, do we build it up to be above a Cat 5 storm surge? At the coast, that would be 30 feet above sea level. At New Orleans, that might be 15 feet.

So you need 20 cubic feet for every square foot. NO City covers 180 square miles. That means 3.8 billion cubic yards of fill.

The Panama Canal moved 232 million cubic yards so doing NOLA would take 16 times as much dirt, ballpark.

I'd say do-able, as a first cut, especially if you dredged Lake Ponchetrain and used the city as a spoils dump.

Fretless recounts the same tale:

Ever been though the Seattle Underground? Seattle was build on a tidal flood plain, which caused all sorts of problems. After a fire, the city required all reconstructed buildings to have reinforced ground floors and entrances on the second floor. Then over a span of several years, the city walled in the streets and built the streets up to the second story level, covering over the sidewalks and connecting the second story entrances to the street. The second stories became the first floors in effect, while the original first floor became building basements.

tmi3rd says that something similar to that is already going on:

Particularly among the coastal residents, i.e. Grand Isle, outer St. Bernard Parish, and the like, most of the construction is up on pilings. It's the damnedest thing to head out to such places that most native Louisianians haven't even heard of (Yscloskey, Toca, Florissant) in St. Bernard and see entire concrete school buildings up on 10-foot pilings... it looks like a spacecraft landing.

Many downtown NO buildings don't begin with office space until about 20 to 30 feet up at the lowest- it's usually parking garages down low, specifically to fight flooding problems. I would have you hearken back to Tropical Storm Allison which flooded out downtown Houston... some poor bastard took the elevator down to check on his car after the flooding but before it had been pumped out. Say goodnight, Gracie...

Anyway, my point is, particularly in the last ten years, there has been very little true ground-level construction of either buildings or new homes. Most of them are raised a minimum of three feet, and the number is usually closer to five feet.

Cirby suggests a Venice on the Missisippi compromise:

You don't need to raise all of New Orleans. You just need to make sure a huge increase in water level and volume can get past the higher ground.

...so make a canal/lake. Cut a big swath right through the middle of the low-lying areas, put tall levee/seawalls on either side of it, widen the Mississippi channel (build tall levees a mile or so from each other), and let the Pontchartrain flow right on through to the sea. Build a couple of nice big bridges before you let the water in (cheaper to make them then), and lete the river run...

Make New Orleans a city of islands, instead of a bowl.

Bbeck scoffs at filling:

The problem with New Orleans can't be compared to places like Seattle or Galveston because the NO soil isn't the same. Unless engineers have come up with a way to build a firm, permanent, hurricane-proof foundation on SILT, all the while having to fight against the will of a HUGE river, then it makes no sense to build New Orleans back where it was. The ground is going to continue to sink.

Asked where all that fill material could come from, Tony responds:

The low areas - make artificial lakes. Most new developments in south FL are using this trick to get the fill needed to raise building sites around the "lake" several feet above ground level.

Then all the lots around the "lake" [Rovian cackle and evil laugh] can be sold for more money because they are now "waterfront" property.

JM Galvin points out that not the entire city need be rebuilt. For many of those most affected by the flooding -- the poorest citizens, living in some of NO's worst slums -- there's a cheaper alternative, and probably one that will benefit them more than simply replacing a flooded slum with a new one:

One program that he gov’t has for places in flood areas is a buyout program. They buy your house and you go elsewhere to live. I think there are about 3 people in Louisiana under federal indictment for playing money games with that program in the recent past.

If that program is offered to people in the NO area, my guess is that a lot would grab it.

I lived on a Long Island barrier island for over 30 years. We never flooded nor had any serious hurricane damage. When that hurricane ripped up North Carolina islands two years ago, cutting some in half, I figured my luck just might be running out. I got a good amount of money for the place and moved inland. If we had flooded and the gov’t offered the buyout, I’d have taken it – after losing everything and a lot of my old neighbors would do the same thing. Since a lot of folks in NO already had their luck run out, I’m guessing they’d be happy to take the money and run.

That would be the cheapest, and probably most politically acceptable answer.

Okay, thanks.

So let me take a little bit of all that and make a new suggestion:

The French Quarter, obviously so important to the economy, gets rebuilt. It wasn't damaged much anyhow.

Port facilities get rebuilt.

Parts of the city that are severely damaged but are high enough to be raised to a reasonable elevation get the Seattle treatment.

Those that are too low are condemned, the property owners paid off, the residents given a hardship allowance check to find new digs. And smaller towns start being built nearby, on higher ground.

Those areas are then dug out to provide fill for the rest of the city, and the water is allowed (eventually) to rush in. Parts of New Orleans are separated by artificial lakes and canals, but connected by bridges.

I don't know. Seems like a lot of that could be done, and the parts of the city most worth saving and/or most easily saved could be saved. The parts of the city not especially worth saving -- and I'm sorry, but there's no particular reason a desperately-poor and crime-ridden slum must be built precisely where it was, as opposed to six or seven miles away in the form of a more liveable town -- or which are too difficult to save just don't get saved.

I think we'll have to rebuild New Orleans. But we don't have to be total jackasses about it. Devastated areas which are fifteen, twenty, or thirty feet below sea (or lake) level will just continue sinking, and there really is no saving them.

Areas five feet below or less can be raised.

And New Orleans will be combination of Venice and Paris, all canals and bridges and quays and water taxis.

posted by Ace at 02:54 AM

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