~ Tim's ~ Nameless ~ Blog ~

Monday, September 06, 2010

When levees fail, people die

That was the thesis of my presentation this year at Rising Tide 5. I titled it, "When can we get some Dam Safety in New Orleans?" because the title, "Levees should be designed and constructed as life safety systems as dams are," just doesn't have the same appeal to the ear.

During my presentation I used Twitter to share some additional information with the audience. I am repeating those links here for those who may have missed them along with some additional resources.

First, the Johnstown, Pennsylvania flood of 1889 remains one of the most horrific dam failures in US history. The web page of the Johnstown Area Heritage Association includes several survivor accounts and eyewitness reports of the terror that flowed down that day. I read parts of the testimony of Mary M. Butler during my presentation.

Although no one has an authoritative count of the current miles of levees in the US, several have attempted it. I used statistics compiled by the American Society of Civil Engineers as presented in their Report Card for America's Infrastructure. And just as elusive is the number of people who actually live in the shadow of levees and depend upon them for their life and safety. I used a 2006 FEMA report which states that 43% of the US population lives in parishes and counties with levees--still not the number of citizens in peril but probably the best guess.

Federal legislation I referenced in my presentation included:
National Dam Inspection Act (Public Law 92-367) of 1972
● The Reclamation Safety of Dams Act (Public Law 95-578) of 1978
● Water Resources Development Act (Public Law 99-662) of 1986
Water Resources and Development Act (Public Law 104-303) of 1996
Dam Safety and Security Act (Public Law 107-310) of 2002

The eye-witness account from Hurricane Katrina I read can be found along with hundreds of other stories and pictures at the Hurricane Digital Memory Bank.

I mentioned my blog about how dismal 100-year level of protection is and I tweeted this link: 100-year protection is not enough.

I also compared the probability of experiencing the 1% annual exceedence event at least once during a 30-year period--26%--to the probability of disaster while playing Russian Roulette, which is 17%. A better explanation of probabilities and what they mean to the average citizen can be found in the ASCE publication So You Live Behind a Levee! and in this reference from USGS, 100-Year Flood–It's All About Chance.

I concluded my presentation with a recommendation to enact a National Levee Safety Program following the recommendations of ASCE and the Association of State Floodplain Managers. I tweeted this link to the ASFPM publication, National Flood Policy Challenges, Levees: The Double-edged Sword, which captures all the main points of my talk, not just the policy recommendations.

The thrust of my presentation is this: As long as we think of levees as protection for houses and furniture, there will be no motivation to increase the level of protection. Houses and furniture can be replaced and the government underwrites the insurance to cover those losses.

We need to talk about levees as serving a higher purpose: levees are often life-safety structures. When levees fail, people die. That’s what’s important and that’s what we should be designing for.

1 comment(s):

I enjoyed your presentation at Rising Tide very much Tim. It was very informative.

By Blogger Michael Homan, at 9/07/2010 2:54 PM  

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