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Are New Orleans’ post-Katrina flood defenses strong enough?

August 24, 2015 at 6:34 PM EDT
Ten years ago, the levees and flood walls meant to protect New Orleans failed against the force of Hurricane Katrina. Since the catastrophe, roughly $14 billion have been spent to upgrade the city's storm defenses. But is that sufficient? William Brangham reports.
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GWEN IFILL: Now to Katrina 10 years later.

William Brangham launches our series with a look at how the city of New Orleans has rebuilt its defenses in areas like the hard-hit Lower Ninth Ward, in preparation for the next storm, when and if it hits.

WILLIAM BRANGHAM: By most accounts, 10 years after suffering a near mortal blow from Hurricane Katrina, New Orleans is blooming.

The economy is thriving, with tourists and new businesses and new residents all flocking here.

Mitch Landrieu is New Orleans’ mayor.

MITCH LANDRIEU (D), Mayor of New Orleans, Louisiana: We have a completely new redesigned education system, completely new redesigned health care system, and a levee protection system that nobody thought you could ever have. And it’s one of the great turnaround stories that the country’s seen in a very, very long period of time.

WILLIAM BRANGHAM: But 10 years on, is New Orleans safe from the next storm? If another big hurricane came charging up the Gulf, would the city’s new hurricane defenses hold up?

COL. RICHARD HANSEN, U.S. Army Corps of Engineers: The system that existed around the city prior to Katrina, the hurricane protection system, was a system in name only.

WILLIAM BRANGHAM: Colonel Rick Hansen runs the U.S. Army Corps of Engineers’ office in New Orleans. He’s overseeing the construction of the city’s defenses.

COL. RICHARD HANSEN: What’s been built now represents the best level of storm reduction that the city has ever had in its history.

WILLIAM BRANGHAM: In the past 10 years, taxpayers have spent roughly $14 billion to rebuild and strengthen the ring of hurricane defenses around the city.

The Army Corps has built flood walls, the kind that failed so catastrophically 10 years ago. They have installed new pumps and floodgates. They have upgraded the large earthen levees that ring much of the city. And they built this. It’s known as the Great Wall of New Orleans, a two-mile-long structure on the eastern edge of New Orleans.

It has got massive closeable gates to block surging storm waters and they, like to boast, it has got enough steel inside to build eight Eiffel Towers.

RENE POCHE, U.S. Army Corps of Engineers: Well, this is the first line of defense for the risk reduction system now. We’re taking the fight to the storm, rather than the storm coming to us.

COL. RICHARD HANSEN: There’s 133 miles of integrated levees, flood walls, pump stations and gated structures. And it’s designed to defend against a 100-year storm surge event or a storm surge environment that has a 1 percent chance of occurring in any given year.

WILLIAM BRANGHAM: These new protections have been tested by several lesser hurricanes, those under the 100-year standard, including Hurricane Isaac three years ago. And the system held up well, with no major flooding inside the city.

But some, like historian John Barry, point out that the standard to which all of New Orleans’ protections were built is considered quite low.

JOHN BARRY, Historian: The city has got an good system that will provide the protection that’s promised, which is so-called 100-year protection. The problem is, that standard sounds great. It’s really an Orwellian phrase. It’s the lowest standard in the developed world.

WILLIAM BRANGHAM: Barry wrote the critically acclaimed book “Rising Tide” about the 1927 Mississippi flood and recently served on the board overseeing flood protections in much of metro New Orleans.

He says that 100-year standard isn’t really enough protect the city.

JOHN BARRY: Flood experts pretty much everywhere and certainly inside FEMA and in the Corps of Engineers agreed at the time that any densely populated areas, certainly like New Orleans, would require at least 500-year protection.

WILLIAM BRANGHAM: But 500-year protection, which means building defenses to guard against much more severe storms, even worse than Katrina, was never mandated by Congress.

And there is another concern when it comes to New Orleans’ long-term storm protection. For 300 years, New Orleans has been buffered by the vast wetlands, swamps and forests along coastal Louisiana. They span the length of the state and go up to 50 miles inland.

But this line of defense is crumbling into the sea at an alarming rate. A football field of land disappears every hour. Over a year, that’s as much land as Manhattan gone.

Denise Reed is one of Louisiana’s top coastal scientists. She and took out to those wetlands to explain why they’re vanishing. She said that the first thing to know is that, over thousands of years, the Mississippi River built the entire coast of Louisiana.

DENISE REED, Coastal Scientist: What happened during that period of time is the Mississippi River, like a very big muddy hose pipe, gradually moved from one part of the coast to another part of the coast, to another part of the coast, and gradually built up this delta that we now live on.

WILLIAM BRANGHAM: Just basically spraying dirt, more or less, left to right across the coastline.

DENISE REED: Yes, weaving its way across.

WILLIAM BRANGHAM: The Mississippi River, by naturally flooding freshwater and dirt over its banks, built up these marshes over the centuries.

But as humans moved in and built levees and walls to stop those floods, the marshes were starved of the sustenance they need to survive. On top of that, oil and gas companies carved tens of thousands of miles of canals through the wetlands to get at the energy underneath.

These canals allowed in more saltwater, which off more land.

DENISE REED: And what you end up with is kind of a recipe for disaster in terms of the wetlands.

We have massive loss, hundreds of square miles of wetland changed to open water during the 20th century. And what that means now is that we’re right close to New Orleans, right close to the airport. And what have we got? We have got open water. That’s not really a good situation.

WILLIAM BRANGHAM: How bad is it? Look at this map.

This shows the coast in the 1930s, when our impact on the area really began. Here’s what’s it looks like today. That grayish area, that is roughly 2,000 square miles of land lost into the Gulf.

Fifty years ago, the land behind you was a thick, old growth cypress forest full of big trees and marshes and grasses. And you can imagine that, as a hurricane came through the area, all of that land would have slowed the energy of the storm down and slowed the storm itself down.

But now that that land is gone, the storm can sail right through.

Denise Reed says it’s not totally helpless. Scientists and engineers have figured out a way to rebuild the wetlands. And they do it by replicating the old Mississippi floods. Engineers cut huge gates into the levees along the river at certain spots, like this big concrete structure here.

That allows freshwater and dirt to flood out into the weakened marshes along. Denise Reed showed me some brand-new land created by one of these manmade funds.

DENISE REED: We starred to have these islands like this pop up. And to begin with, they were just mud. And now look at what we have got here, something quite special.

This is the kind of thing that shows us that there is a sustainable future for coastal Louisiana. This is a solid piece of land. It’s probably the newest land in the United States.

WILLIAM BRANGHAM: The state of Louisiana would love to construct dozens of projects like this. The state drafted an ambitious master plan to rebuild parts of its coast, but its $50 billion price tag has barely been funded and it could end up costing double that.

The state and the federal government has already put millions in, and the BP settlement will add several billion more. But the plan is still unfunded. So, the question is, to restore the coast and protect the city, who is going to pay? There’s plenty of blame to go around.

JOHN BARRY: The politicians in the state of Louisiana all like to tell their voters, we’re going to get it from the federal government. That is…

WILLIAM BRANGHAM: We will fix the coast, and the feds are going to pay?

JOHN BARRY: The federal government is going to pay for it, which is,, frankly, politically not a — it’s a fantasy.

WILLIAM BRANGHAM: Mayor Mitch Landrieu argues that the whole nation has enjoyed the fruits of Louisiana’s coast, from its seafood, to international shipping and especially its abundant oil and gas.

But that’s come at an environmental cost, and now, he argues, the whole nation ought to help fix the damage that’s been done.

MITCH LANDRIEU: It’s not engineering that’s the problem. It’s resources that are the problem. And it’s the political philosophy of somehow that we can destroy your land, we can put an entire city at risk. That’s not really going to work.

And so Louisiana is willing to drill, but we ought not do it if we don’t restore. And the oil and gas companies and the federal government and everybody ought to be really aware of that, because it’s literally an existential threat.

WILLIAM BRANGHAM: This week, as New Orleans commemorates those lost to Katrina and celebrates the city’s revival since then, its residents take some comfort that their flood protections are far better than the ones they had 10 years ago. But to their south, the land between them and the Gulf of Mexico continues to slip away.

For the PBS NewsHour, I’m William Brangham in New Orleans.

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