Friday, September 16, 2005

LEVEE DESIGN: by Russ

It’s been hard to put thoughts together since Hurricane Katrina made landfall. I’ve found myself yelling at the TV (ideology makes no difference here, Fox, CNN & MSNBC are equally clueless), and I can’t read newspapers without kicking my BP up another 20 points. Every time I’ve sat down to write an article since Labor Day it’s ended up with a flurry of expletives, and I’ve sent countless rants to the cyber-shitcan. The absolute STUPIDITY demonstrated by some members of the MSM has me flabbergasted. The logistics involved with evacuating a MAJOR American city, preparing for landfall of a Category IV hurricane, rescuing people who stayed/were left behind in the path of the storm, sealing levee breeches, and dewatering the Lost City of New Orleans are all examples of engineering in action. My day job is designing infrastructure, so I’ll focus on that for now and leave the logistics questions for later.

Many people are screaming about the Corps of Engineers and the fact that the New Orleans levees were only designed to protect the city from a Category III hurricane. This is fair criticism, and I might join them….but I’d like to see the work product of the design team before I line them up against the wall. I’ve never designed anything as critical as a levee or floodwall for a major city, but I know how the process works. Engineers don’t set policy. We calculate the effects of all types of events and select one based on cost/benefit analysis and probability. The engineers who designed the levees for New Orleans didn’t just pull “Category III” out of a hat; they were working with parameters handed down through the bureaucracy, and they have certain assumptions that help them justify the design process.

1. NO levee will protect against a Category V hurricane. The biblical winds produced by the storm will level any structure behind said levee, and the massive amounts of rainfall produced by this event would have flooded New Orleans without overtopping the over-designed structures. You would end up with piles of debris & a smaller level of flooding (possibly turning into the flooding we saw when the power to the pumps keeping New Orleans dewatered was lost due to the destruction of the power grid or the structures housing the pumps). Preparing for a Category V hurricane is a little like building your house to withstand a direct impact from a falling 747. At some point, the cost becomes prohibitive.

2. When a Category IV hurricane is forecast to make landfall in a major American City, the prudent thing for local government to do is to GET THEIR PEOPLE THE HELL OUT OF THE WAY. Evacuation plans were in place, and even though most engineers have a negative opinion of the competence of politicians, it would take a cynic of the first order to visualize “the Ray Nagin Memorial Motor Pool” from their vantage point in the mid-sixties (when the levee designs were originally done). Part of the cost/benefit analysis is the recognition that structures and possessions can be replaced, but people are precious. Engineers COULD allow for the fact that local governments would refuse to evacuate their residents or they could throw in an extra 30% of design costs required to cover corruption and incompetence, but this would be a political decision, not an engineering decision.

Even now, I can’t make any additional points without starting to rant about the stupidity of the media, and the crass political posturing coming from local & state politicians & their national apologists.

That’s the trouble with trying to argue facts with people willing to use bodies to score political points: every time you make a rational argument, they go out and find a dead body to throw into the dialogue. I think our national discussion about how to protect Americans from disasters like Katrina is only beginning, but the first round of talking does nothing to alleviate my cynicism.

~by Russ From Winterset, House Contributor

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