Katrina to Challenge City's Floodwater Infrastructure
ALEX CHADWICK, host:
This is DAY TO DAY. I'm Alex Chadwick.
Hurricane Katrina and New Orleans--it looks as though the worst of the storm has missed the city. It is weakening. The damage not expected to be as bad as once feared. But somehow the threat of hurricanes seems to get worse and worse for the city. NPR's Danny Zwerdling did terrific reporting a couple of years ago which explained to me for the first time the context of New Orleans and hurricanes.
Danny, welcome to the show. And just lay out for us--Would you?--what it is that makes New Orleans so vulnerable.
DANNY ZWERDLING reporting:
Hi, Alex. When the French settlers first came to the area around New Orleans almost 300 years ago, some of them said, `This is crazy to build a settlement here. We're below sea level.' New Orleans is sort of like a bowl. There is the Mississippi River that goes all around it, and there's a huge Lake Pontchartrain that's on the north side of it. And the settlers said, `We're going to drown here during a flood.' And other settlers, who ended up winning the argument, said, `Well, we have an idea. We'll just build a huge wall, sort of like the Great Wall of China.'
And they started building levees; they're basically like walls made of mud or now concrete. And in the 20th century, the US Army Corps of Engineers continued that project in a more high-tech way, and they have now built the world's biggest system of levees, these ridges all around the city, to protect it from floods from the Mississippi and from Lake Pontchartrain.
CHADWICK: But then if the water does get in, it's going to be held there by those levees. And they have this system of pumps that you explained.
ZWERDLING: The big fear is that if the hurricane this morning had stalled over Lake Pontchartrain, just to the north of the city, the ferocious winds could have pushed the water from the lake over the levees, over the walls, into the city, and then the whole bowl of New Orleans would have filled up and been underwater. That hasn't happened. Now they do have this amazing system of pumps. They have--I think it's like 22 pumping stations with huge turbines, sort of like you see in pictures of, you know, Hoover Dam.
ZWERDLING: The government officials who put these in place said, `Well, since we have these levees to protect the city from the giant hurricane floods, let us just build the pumps to take care of big rainstorms.' So the pumps can get rid of lots of rainwater, but Lake Pontchartrain ever overflows during a hurricane, the pumps themselves will be flooded and they'll be useless.
CHADWICK: What about the non-mechanical systems? You reported on that, too, the whole coastline there.
ZWERDLING: See, the natural environment is the greatest protection that New Orleans has ever had from hurricanes, but it's disintegrating. There is this huge area of wetlands, and when you go up in a helicopter, it looks like vast prairies in every direction. They stretch several hundred miles along the Gulf of Mexico. In some places, New Orleans is buffered from the Gulf by 50 miles of wetlands. And they look like prairies that get mushy from time to time. When a storm roars up out of the Gulf and it goes over these wetlands, this land, the land sort of sucks the power out of the hurricane, and so by the time it hits the city, it's much weaker.
Well, what's happened is, first of all, the oil and gas industry has been slicing up the wetlands for decades now in their search for oil. And second, it turns out that the very levees that were designed to protect the city from floods are causing the wetlands to die. The wetlands need to be flooded every once in a while. They need that covering of goo to replenish. And every year, Alex--listen to this--every year, wetlands the size of Manhattan crumble and literally turn into open water, so that that cushion that used to absorb the power of hurricanes is disappearing.
CHADWICK: NPR's Danny Zwerdling on hurricanes and New Orleans.
Danny, thank you.
ZWERDLING: Thank you, Alex.
CHADWICK: I'm Alex Chadwick. We'll be right back with more from DAY TO DAY.
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