Thursday, May 19, 2011

NOT PJ: One Mississippi, No Mississippi

_BernardDarntonThis week Bernard Darnton sails down the Mississippi on a raft of bad news.

Nature’s relentless might is on show again, this time in the Mississippi River basin. The river’s catchment is vast - nearly half of the United States - and the water’s all shown up at once. Whether you count in metric or imperial units, there is a cubic shitload of water coming down that river.

The situation is so unusual that it makes an introductory ethics class sound realistic. An out-of-control railcar carrying 80 billion tonnes of water is careering towards New Orleans, population 1.2 million. If you could push a fat man onto the track and divert the railcar to Morgan City, population 12,000, would you do it?

In the ethics class three quarters of the class say it’s wrong to throw fat people at railcars and one quarter say it’s wrong to let the railcar crash into a million people when you could prevent it. Then they argue for the rest of the class about “normative ethics,” “consequentialist ethics,” and so on. Nobody, fat or otherwise, actually dies.

If you’re in charge of the Morganza Spillway however, where the Army Corps of Engineers keeps 125 caged railcar-diverting fatties, the choice of whose homes to destroy is real. And they’ve decided that Billy Bunter is going to take one for the team.

Right now, the control structures designed to contain the Mississippi are more stretched than this railcar-crashing-into-fat-man analogy. The last time an analogy was this stretched was during the flood of 1973, when the Old River Control Structure was compared to King Canute trying to hold back the tide by getting every lard-arse and chubby-cheeks in Humberside to line up along the beach. It was feared then that a torrent of ridiculous wordplay could completely undermine understanding and change the course of writing forever.

The Old River Control Structure, a set of gates that control the distribution of river water, and the Morganza Spillway are not just floodgates, there to divert water after heavy rain. Their real purpose is to keep the Mississippi flowing down its existing channel, even though it would rather jump its banks and take a shorter, steeper route to the ocean.

CaptureOver millennia, the Mississippi has whipped around like a fire hose, with its delta moving across from the Florida panhandle almost to Mexico and back again as old channels silt up and new channels are eroded. The river no longer has any desire to follow the current channel through to New Orleans and is fighting to switch course to the west, down the Atchafalaya River and into the Gulf of Mexico.

Without the control structures the area wouldn’t just flood, the river would change its course permanently as it scoured its new path to the sea. If the Old River Control Structure was to fail - something that almost happened in 1973 - it would make the chaos of Hurricane Katrina look like a perfectly scripted tour of a clockwork factory.

If the Atchafalaya captured the Mississippi and the lower river ran dry the effects would be staggering. The Port of South Louisiana extends for 90 km along the river’s banks and handles the imports and exports for 33 states - over 200 million tonnes of cargo a year. The river banks are home to any number of oil refineries that need fresh water to operate. If the river became un-navigable the cost would start at $300 million a day.

Battling the Mississippi seems like an impossible task. The engineers are fighting geography, gravity, and statistics. One day the 500- or thousand-year flood will come. In the long run it’s bound to happen. And in the long run it would probably make more sense to let the river follow its natural inclination and let industry relocate along the new water course. But it’s just never the right day to pull the pin on millions of livelihoods and billions of dollars worth of infrastructure.

The current flood is bigger than the flood of 1973 but the control structures are in better shape and have been extended to spread the load so they will probably hold. Tune in next week to discover whether the Old River Control Structure is a remarkable feat of engineering and a testament to human ingenuity and grit in the implacable face of nature—or if it was a vast, expensive and futile government boondoggle, doomed to failure when pitted against irresistible forces.

Bernard Darnton sails down a river of metaphor every Thursday here at NOT PC.

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2 Comments:

Blogger Luke H said...

"... it would make the chaos of Hurricane Katrina look like a perfectly scripted tour of a clockwork factory"

Brilliant! :-)

5/19/2011 02:47:00 pm  
Blogger Kiwiwit said...

Old Man River changing course would make less of a mess of the American landscape than your analogies make of Not PC's elegant blog.

But well put!

5/19/2011 05:54:00 pm  

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