Sunday, November 11, 2007

Level of protection

This is not a new topic. We’ve been talking about this in New Orleans for two years, so you’d think folks would understand it by now.

Okay, so maybe it’s not possible for everyone to get this.

But The Times-Picayune? Why don’t they have this figured out yet?

It’s not that bad if you stick to the simple facts. The so-called 100-year flood is really the 1 percent flood. It’s the elevation of floodwater that has a 1 percent chance of being exceeded in a given year.

Simple but essential. Because that’s the elevation that FEMA will use to establish the Base Flood Elevation. That’s the elevation you must be at or above to be eligible for Road Home and SBA funding for new construction. That’s the elevation you must meet or exceed to be eligible for the National Flood Insurance Program preferred rates.

And as you may have heard, that’s the elevation that is the basis of the ongoing work to build and improve the levees that surround much of the New Orleans area.

So we see how important this is. That’s why it pains me every time I read The Times-Picayune struggling to grasp this basic but powerful concept.

The most recent infraction arrived in front of our FEMA Travel Trailer on Saturday morning. The subject story was just a recap of the WRDA bill and what it means to those of us who live in “that part of the world.”

About five paragraphs down, the paper reminds:

"A 100-year storm is a storm that has a 1 percent chance…"

So far so good.

"…of occurring, or being exceeded,…"

Yes! Important to remind folks of that point.

"…in any given year..."

Outstanding! It’s like watching an Olympic ice skater spinning gracefully through the air.

"…during a century."

CRASH!!!! But the skater hits the ice with a thud and a groan.

During a century?? Where did that come from?

Sorry guys, but basic statistics rely upon predictability that comes from long-term randomly dispersed events. No one can tell you when the next big hurricane is going to hit, but we can certainly know the probability over given periods of time.

If I may get all mathematical on ya'll, the probablility of seeing the 1 percent event in any given 100-year span (or century) is about 63%. Anybody who has my PowerPoint presentation from Rising Tide 2 can check the graph and come up with this answer. Just don't ask The Times-Picayune.

Oh well, perhaps they’ll figure it out in the next two years. Or more.

1 comment:

Sophmom said...

Slides 16 and 17 put that in pretty good perspective even for doofuses (or at least non-engineering types) like me. It's amazing that the T-P doesn't get it, but I guess not really. *sigh*

I'm finally reading Rising Tide. Wow. I can't put it down. Honestly, it makes a lot of cultural things make sense. This has been a mess since the beginning, hasn't it?

It looks like our Guv is gonna get his rain. We'll never hear the end of it. *more sighing*