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Rebuilding New Orleans With Science
EccentricAnomaly writes "The New York Times has a discussion of flood control methods in use in Holland, England, and Bangladesh that could be used in the rebuilding of New Orleans. Of particular interest is the $8 billion Delta Works built by the Netherlands in response to the North Sea flood of 1953, which almost destroyed the city of Rotterdam, but for a heroic captain who plugged a breach in a dike with his ship." From the article: "While scientists hail the power of technology to thwart destructive forces, they note that flood control is a job for nature at least as much as for engineers. Long before anyone built levees and floodgates, barrier islands were serving to block dangerous storm surges. Of course, those islands often fall victim to coastal development."
I noticed another NYT story on lost cities, which would be interesting to the 'abandon New Orleans' camp:
h tml
http://www.nytimes.com/2005/09/06/science/06lost.
There are 10 types of people in this world, those who can count in binary and those who can't.
Did you read the next sentence?
:-)
Long before anyone built levees and floodgates, barrier islands were serving to block dangerous storm surges. Of course, those islands often fall victim to coastal development.
That kind of destroys the entire point of a break island.
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"Long before anyone built levees and floodgates, barrier islands were serving to block dangerous storm surges. Of course, those islands often fall victim to coastal development. "
Levees and floodgates, as used in the US, do not generally mitigate the damage caused by storm surges -- they are used to block flooding from inland sources like rivers.
"...some artificial barrier islands, rather than further changing the face of the earth"
Artificial barrier islands = changing the face of the earth
Barrier islands migrate into the land over time. They are really just giant versions of the sand ripples you'll see at the edge of almost any (near still) body of water. If we really want our coastlines to operate in a natural fashion, we've got to allow barrier islands to form, move to land, and respawn.
The real problem with NOLA is that the Mississippi River delta is not allowed to regenerate itself by silt deposition. Most conservationists would argue that less flood control is necessary, not more.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
OK a light hearted comment, but I just read in the NYT a great column on the contrast: NYC was hit with fire, NO hit with water.
NYC could deal with fire, because we've learned to fight fires locally. We build to prevent it, and we all pay a premium on goods and services through the system due to the costs of sprinkler systems etc in the supply chain. We spend city $$ on fire services, and emergency response capabilities.
NO couldn't deal with water, because since the 60's the Federal gov't has taken over response to floods. Local officials are reduced to writing plans that ultimately read "wait for the Feds to arrive with help".
Moreover, with an agency like FEMA, and federal subsidies for flood insurance, he makes a persuasive argument that US gov't policies have, in effect ENCOURAGED the building of homes and businesses in flood prone and coastal regions.
If those homeowners and businesses had to pay a MARKET cost for insurance, how many would have built there? And if there wasn't a FEMA (which has historically compensated flood/hurricane victims even or especially if uninsured) would people be so lasseiz-faire about their families, dwellings, and belongings in the path of destruction?
Persuasive reading.
-Styopa
The broken canal walls are all up near the Lake seawall built in the 1930s, reclaiming land once swamp (and lake bottom). City Park is a giant park through which the Bayou St. John still flows, along its ancient path, into the middle of town (thru some big pipes in places) to the center of the bowl, the bottom of New Orleans. All that is totally under water now: the 17th Street Canal was the main burst that flooded the town, and runs along the West edge of City Park, past the Bayou.
;). But at least the Dutch will actually do it: they actually do things. Instead of leaving it up to the Army Corps of Engineers, which now must be spelled Corps e , which totally failed their mission - though it looks like they were set up for failure by the civilian leadership, for decades.
We should expand City Park to encompass the entire Bayou area, with no development, and lots of canals. Expand the Bayou itself in the bottom to become a giant reservoir. When storms approach, pump out the reservoir. Make all drains pass through the reservoir, a giant buffer. When rain and failed seawalls allow water into the city, funnel it into the reservoir, buying time. Pump the reservoir into the Mississippi and the Lake.
The seawalls and levees themselves are not fault-tolerant. They're static, brittle, and take the whole city with them when they break. Those walls should all have rail lines along their inhabited sides, separated from the water by the wall. When a storm approaches, dumpable sandbags can be rolled into place behind risky sections, or into broken sections, or just into staging areas for delivery by helicopter, boat or amphibious vehicle, or even human "bucket brigades" when all other vehicles fail. Ahead of the storm, the rails can carry cars of evacuees out. And the other 99.5% of the time, without emergencies, they can carry cars instead of highways (most cars on I-10 are "just passing through"), passengers and freight.
Or we can just put the Dutch in charge of the city. Then they'll do all those things I mentioned, and probably something with windmills. Amsterdam and New Orleans have a lot more in common than just negative elevation - and I'm not referring just to decades of Spanish dominion
Or we can just let New Orleans rot. Along with the rest of the country. If it can happen to a city everyone loves so much, that's so important to our economy, where everyone knew it was RISK #1, why shouldn't it happen everywhere eventually - and not as slowly as in the old World Capital of Molasses.
--
make install -not war
A similar plan was proposed this year. The New York Times hated it. Here's the quote:Hard to tell whether it was genuineely a bad plan, or the NYT hated it simply because it was Bush's proposal, but we are at least considering the ideas used in Europe.
Socialism: a lie told by totalitarians and believed by fools.
The problems with New Orleans runs far-far deeper than polluting etc.
New Orleans is placed on a river delta. After the sediments in a delta are deposited they are guaranteed to subside. It's a consiquence of compaction, de-watering and the isostatic response of the lithosphere below the basin to the extra load. Unless more sediment is added continuously the delta will eventually (and quite quickly in geological and indeed historical terms) sink beneath the sea.
When New Orleans was founded a few hundred years ago it was above sea level. (after all, who would found a town on a salt marsh?) Since then it's subsided continuously until today a great deal of the city is now below sea level and a great deal lower than the river (which has since built up its base by depositing sediment).
When the corps of engineers stopped the river naturally switching its channel (which it does around once every 1000 years) and straightened the current channel they put in motion a set of events which meant that the delta lost its sediment load to further out in the Gulf of Mexico as the river is flowing at a greater rate. This has caused the coastline (and all the natural defences) to not be replenished and go below the sea.
You may like to see this google cached article from a Baton Rouge newspaper in 2002. It gives a decent overview of the situation.
As a geologist, I would be in the camp which suggests that the government take this as an opportunity to move the city to higher and more stable ground and abandon the old city to be an archaeological curiosity and tourist attraction. Rebuilding it would merely prime the charge for an even bigger loss of life when, not if, the river breaks its banks. This time only the low-level lake to the north broke through which soon equalised its level.. this wouldn't happen with the great river.
How long do you want to fight a losing battle with the planet? How high do you eventually want the levees to be before you give up? When the city's subsided to the point where it's an isolated bowl in the ocean?
I know it's not going to be abandoned, there are too many politicians who have staked their carreer on the "we will rebuild it" bravardo and a King Kanute attitude.
(Before anyone corrects me about King Kanute, I know that the popular story is wrong, the King was trying to show how impotent he was rather than believing that he could actually stop the sea.)
Agrajag: "Oh no, not again!"
For Pete's sake, this kind of thing is exactly FEMA's mandate: provide resources to avert and mitigate emergencies. In other words, FEMA should have had the place crawling with responders and National Guardsmen the moment the state of emergency was declared on August 26th. I'll bet you 25 bucks that the head of the agency not only keeps his job but gets a raise. Seriously, I'll make that bet.
I say this and I'm one of the people who thinks that FEMA is way too quick to offer people money to rebuild their waterfront condos every time a flood or hurricane happens. But when push comes to shove, it is our nation and our government's responsibility to avoid the kind of human tragedy that happened in New Orleans, and that job primarily belongs to FEMA.