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Updated Federal Flood Maps Of New Orleans: An Outline For Disaster?

Orleans Parish is seeing its flood maps updated for the first time since 1984 today. More than half of the city is moving out of the so-called “high risk” zone—this comes with lower flood insurance rates, which many are celebrating. But in June, Tulane historian Andy Horowitz penned a controversial op-ed in the New York Times. He called these maps an “outline for disaster.” WWNO’s Ryan Kailath sat down with Horowitz this week to discuss.




A lot of New Orleans is celebrating new flood maps. But you had a different reaction—why?


Well let me tell you the story of when I first discovered these maps. Bob Marshall had written a great article about the anticipated changes in the flood maps, and pointed me towards the portal to find out what the changes were. So I logged in and I was poking around, I put in my address, some friends' addresses, other places I cared about, and it seemed like everywhere I looked was coming out of the floodplain.


So then I started challenging the system, and I put in places where I knew that there had been ten, twelve feet of water during Katrina, and even many of those places were coming out of the 100-year floodplain, meaning they would no longer be subject to the flood insurance requirement. And I thought I had to be using the program wrong! There was no way that these places could have less than a 1% chance in a year of flooding. So I actually wrote to Bob Marshall, who had written the article, and said "I don't understand how to use this FEMA portal," and he said "No, you're using it correctly."


At first, I, too, was very excited, and I still am relieved that FEMA (Federal Emergency Management Agency) believes that New Orleans has this level of safety from flooding. My concern is that the engineering precision—and I want to be clear, I don't doubt the science that they used, I'm sure that they were people of good faith and very intelligent scientists who developed these maps—but they were probably, it seems to me, so precise in trying to figure out the likelihood of certain kinds of flood events that they missed the larger truth that New Orleans is terribly vulnerable to flooding.


What the new map says is that most of New Orleans has a less-than-1% chance of flooding in any given year, they call this the 100-year-floodplain, but as a historian I know that many of these places have flooded several times over the past century. They flooded not just during Katrina but during Hurricane Betsy in 1965, during a hurricane in 1947, in 1915 they flooded, and so, as New Orleanians we know how vulnerable our city is, and I fear that that's not reflected in these maps.


Now, supporters might say that since then we've gotten this $14 billion levee system. Will that keep New Orleans from flooding?


I hope so. I live here! I really hope that I am wrong. I think one of the things that has happened here is that the new flood maps incorporate many of the good things that have happened over the past decade without incorporating some of the troubling things that we know are going to happen over the next decade and after.


We know that the climate is changing and with rising seas and warming seas there will be bigger storms. We know that our wetlands—which are crucial protection against hurricane storm surges—that those are falling away, which means that our city gets increasingly vulnerable every day.


And so this sort of static snapshot that the FEMA maps offer doesn't reflect—if you're considering buying a house now you might have a 30-year mortgage and hope to live there for 30 years! So we have to also be thinking about the future.


Do you think that the new maps accurately represent risk for the people of New Orleans?


For scientists, risk is a technical term. I suspect that these maps accurately reflect the modeling that some very good scientists did to try to predict what certain kinds of certain kinds of hurricanes or certain kinds of rain events would do in the city given the flood defenses in place as we have them now.


Risk, as most of us use it in our daily life, is a question of how safe are we? And though FEMA and the city says the maps are not meant to be used this way, the common sense way to read those maps, I believe, is to look at it and say "Wow, we're pretty safe. We've got a less than a 1% chance of flooding here. Let's buy this house, let's not worry about it. Maybe even let's try to save a few dollars for other priorities by not having our flood insurance." I think that the situation is way too risky for that.

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