Rising Tide V: Levees, Dams, Failure

WHY CAN’T WE GET SOME DAM SAFETY IN NEW ORLEANS?

Tim Ruppert, Engineer/Rising Tide

1972(?) careful Congressional description of what a dam is. 1996, even more specific: “A levee is not a dam.”

Why should you care? You’re a few hundred yards from the river. Does the label matter? Yes, here’s why.

I’m a civil engineer. When designing/evaluating safety of a dam, 1st thing you calculate is: if this dam breaks, how many people die? How many living, breathing people will be crushed, drowned, killed otherwise? A dam is considered a life safety system. The more people involved, the more carefully we have to design, construct, and maintain our dam. Also calculate other potential losses later.

Compare this to how we design levees: 1st question engineer asks is, How much flood damage do the homes/businesses in floodplain sustain per year, and what would the damage costs be if we build the levee? Want to save as much $ as possible. Corps of Engineers has a rule: you can’t build a levee that doesn’t have a benefit. But does it benefit the taxpayer? We don’t consider it a life-saving system. We don’t ask how many people will die if it fails. We assume people will be evacuated. Not realistic. We know people die when levees don’t hold.

Testimony: “My past life died that day with Mother.”

1600 people died. That’s pretty horrific.

So how did we get to this point? Built dams to protect lives; levees to protect houses, carpets, furniture. This denial of killing potential of failed levees has huge consequences. If levee fails, just replace carpet/tv, right? And federal government will sell you flood insurance to pay for it.

Levee systems being created around N.O. right now designed to 100-year level of protection. Misleading name. If you live in flood zone for one year, your risk is 1/100 that you will experience the “exceedence flood.” Most people stay longer than a year. So here are some real numbers:

–within 30 years, 26% (before you can even pay off your mortgage). Russian Roulette has a 17% chance of disaster.
Who came up with this ridiculous 100-year standard? Goes back to national flood insurance. All about property: no death benefit. Homeowners/politicians forgot a levee protects far more than carpets/furniture. May be OK for some areas, but in densely-populated areas, 1/100 standard is irresponsible and dangerous–not just me saying this. Natl Academy of Engineers (specifically as it applies to N.O.) , Assn of State Floodplain Managers (500-year standard minimum acceptable in urban areas). 500 years = 6%. 100 years = 26%. Am Socy of Civil Engineers: have not recommended a particular level of protection–wants levees to be engineered by risk-based assessment (meaning, calculate how many people will die). I agree.

Say it with me: WHEN LEVEES FAIL, PEOPLE DIE. And we need to remind our elected officials of this.

Congress taking baby steps toward a program modeled after dam safety. But we have to push it all the way, including funding. Dams and levees share this: when they fail, they die. Those Americans who live with levees should not find that out the hard way.

SANDY FROM LEVEES.ORG: What can we do to help you get levees certified as dams?

RUPPERT: Bureau of Reclamation major player in dam safety. Agencies responsible for building levees take diff approach. Need to call congressional reps and get their full support for the National Levee Safety Program.

Data we use to extrapolate 100-year storm drawn from very small database, only since WWI (diameter of eye, windspeed, etc.)

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2 thoughts on “Rising Tide V: Levees, Dams, Failure

  1. […] This post was mentioned on Twitter by Derrick and webinista, Robin Kemp. Robin Kemp said: Rising Tide V: Levees, Dams, Failure: http://t.co/quXV74U #RT5 #katrina #katrina5 #nola #gulf #levee #politics #Corps #fail […]

  2. Its time for some dam safety – you are so right! I don’t recall the levee’s being placed on the Louisiana GIS CD circa: 2000, BUT so far as I can recall…. the dams were included – alas they were mostly private dams. I.E. “private dams” – turned over to private land owners after they were created.

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