Taking Down Levees in Louisiana

  • The Mollicy Farms River Forest Levee (Keith Ouchley, Louisiana Nature Conservancy)

Man made levees line the banks
of the Mississippi River and its
tributaries. They protect towns
and they allow farmers to plow
the bottomlands. But levees come
at a price: habitat destruction
and worse flooding downstream.
Now, more people are calling for
taking down levees and returning
floodplain areas to their natural
state. Samara Freemark
reports from Louisiana – the end
of the line for the water that
drains from the middle of the nation:

Transcript

Man made levees line the banks
of the Mississippi River and its
tributaries. They protect towns
and they allow farmers to plow
the bottomlands. But levees come
at a price: habitat destruction
and worse flooding downstream.
Now, more people are calling for
taking down levees and returning
floodplain areas to their natural
state. Samara Freemark
reports from Louisiana – the end
of the line for the water that
drains from the middle of the nation:

The Mollicy Farms site in Northern LA provides a striking example of just how dramatically a levee can remake a landscape.

“Here comes the river down through here.”

Keith Ouchley is with the Nature Conservancy, and he’s showing me an aerial photo of Mollicy Farms. The site is split in half by a river. On the west side, there’s 30000 acres of primeval forest. On the east side, a swath of cleared land.

“Once, it was forest in the lower area of tupelo and in the upper areas of sweet gum. And every year the river would overflow and flood the forest.”

In the late 1960s, soybean farmers cleared the area built levees to hold back the annual floods – giant earthen walls, 150 ft wide at the base and 30 feet tall. Ouchley grew up in the area. He remembers the first time he saw the site after the clearing.

“I thought at the time you could almost see the curvature of the earth, looking across this massive clearing up there.”

Levees protect a lot of land for farming. But some people are starting to wonder if they’re worth the cost – not just the money it takes to build and maintain them, but the damage they do to ecosystems.

Denise Reed is a geologist at the University of New Orleans. She says hundreds of species depend on floodplain habitats- and without flooding, those habitats vanish.

“The river is the lifeblood of floodplain and delta ecosystems. When you build levees and you cut it off, we cut off those habitats from the river. And essentially they just degrade and die. Putting it back would definitely be a good thing.”

Levees might also raise the chances of truly catastrophic flooding downstream. Whenever there’s a lot of water in the river – say, there’s heavy rain upstream – that water shoots straight down the channel with enormous force. And it sometimes breaks through downstream levees that protect homes.

If you take down levees upstream some of that water has somewhere else to go – out into the forest or wetlands, where it spreads out across thousands of acres.

All of which is why Denise Reed says, instead of building more levees, it might be a good idea to take some down.

“Just because we’ve had levees on the river for the last hundred years or so doesn’t mean to say we’re always going to have levees on the river. The challenge for us is letting nature do its thing while still allowing us to navigate on the river and bring ships in, and that kind of things, and for us to live places where we’re not going to be flooded out. We can do that.”

After catastrophic flooding in 1993, the federal government started buying up levee-protected land along the Mississippi and its tributaries with an eye towards restoring floodplains. But the memory of that flood faded and funding for the program fell off.

That left private groups like the Nature Conservancy to take up the effort.

This summer they’ll punch holes in the levee at Mollicy Farms. As the water rises in the spring, it will gradually seep out onto the landscape, restoring the floodplain.

“50 years, 100 years, you’ll be able to take a boat out through nice, mature, bottomland hardwood floodplain forest. You know, see water moccasins and catch bluegill brims and alligators floating on logs and that kind of thing.”

Ouchley says he’d like to see the program replicated in floodplains all over the country.

For The Environment Report, I’m Samara Freemark.

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