MELISSA BLOCK, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Melissa Block.
Today, Hurricane Edouard landed in Texas and was reduced to Tropical Depression Edouard. As hurricane season picks up, there's a lot of debate along the Gulf Coast over how best to protect against a big storm. One approach is restoring wetlands. Experts say they act as natural speed bumps.
NPR's Andrea Hsu explored one of those wetlands right in the city of New Orleans.
ANDREA HSU: The Bayou Bienvenue is separated from the city's Lower Ninth Ward by a levee. The Lower Ninth had some of the worst flooding after Hurricane Katrina. On the land side of the levee, there are a few restored homes, but many more in various states of disrepair. Mostly, there are empty overgrown lots. Cross over to the other side of the levee and you'll find a landscape that's almost as stark - a stretch of open water dotted with dead trees.
(Soundbite of water gushing)
Mr. ANDREW LEAF (Student, University of Wisconsin-Madison): That's one of those cypress stumps. They're kind of hard to see because the water is so turbid.
HSU: Andrew Leaf and Amanda Perdzock are out in a canoe. They're students from the University of Wisconsin-Madison, and they're part of a group that's been studying a 430-acre triangle within the bayou. Their work is part of a proposal aimed at restoring what used to be here - a cypress swamp.
Mr. LEAF: Fifty years ago, this would have been cypress trees. And the water would have been a lot more shallow; we might not be able to get around in a canoe.
HSU: The students use the canoe to get to their test sites. They're looking at water samples and vegetation. And they're figuring out ways to bring sediment and fresh water back to the swamp. After all, Andrew Leaf says, it's salt water that killed the trees. Here's what happened. In 1965, the Army Corps of Engineers opened a channel called the Mississippi River Gulf Outlet, Mr. Go for short. It was built to provide a direct route from the Gulf of Mexico into New Orleans. Over the years, salt water seeped from the channel into the bayou. Leaf has seen pictures before and after.
Mr. LEAF: You can really see it in the air photos. In the late '50s, this triangle was full of trees. It was almost fully vegetated. And then by the mid-'70s, it was open water.
HSU: Now, the Army Corps says it's going to close Mr. Go as early as this fall. And the proposal to turn that triangle back into swamp is in the running for federal funding. Andrew Leaf says their project represents only a tiny part of restoring a system of wetlands needed to protect the region. But it would be a good start.
Out in the open water, it's hard to imagine what a healthy swamp would look like. Fortunately, you can visit one not too far away.
Professor BOB THOMAS (Environmental Studies, Loyola University): We're in Lafitte, Louisiana about 15 miles south of New Orleans.
HSU: Bob Thomas chairs the Environmental Communications Department at Loyola University.
Prof. THOMAS: You're looking at a truly beautiful swamp.
HSU: We're walking on a boardwalk through 41 acres of thick vegetation, including cypress trees old and young.
Prof. THOMAS: It's really rare to go out and see cypress trees germinating everywhere, like we're seeing today. And these are just germinating. See the little bitty ones right there?
HSU: And here's another sign of a healthy swamp - frogs. That's the commotion in the background.
Prof. THOMAS: Listen to this next one, raht-raht-raht-raht. That's a squirrel treefrog, and it's the mating call.
(Soundbite of frog mating call)
Prof. THOMAS: Hear that little click, click, click, click, click, click, click? It's a cricket frog.
HSU: And then there's my favorite.
(Soundbite of frog mating call)
Prof. THOMAS: The narrow-mouthed toad. And right now, they're calling in the water with just the tip of the snout sticking out of the water. To get out there and find one would be impossible.
(Soundbite of laughter)
HSU: It turns out the same vegetation that provides cover for those frogs provides protection from storms.
Prof. THOMAS: So if you had a big surge that came through this, imagine this - an eight-foot surge of water hit the edge of this, as it progressed through the forest, it would be diminished because it would be absorbed and slowed down and broken down. So at the other end of the forest, you'd have much less of a surge.
HSU: Just 100 years ago, much of the Louisiana coast would have had this kind of natural protection, then over time came development. Manmade levees that prevented floods but changed the way sediment naturally replenished the wetlands, also channels for shipping and for oil and gas pipelines.
Now, the wetlands are disappearing alarmingly fast, and Bob Thomas wonders how long this swamp will be here.
Prof. THOMAS: We feel like we're standing in a pristine area. But we could drive one mile in several different directions and find devastation from saltwater intrusion. It makes you worry.
Mr. LEAF: Those are enormous stumps.
HSU: Back in the city, Andrew Leaf and Amanda Perdzock have brought me to the edge of the Bayou Bienvenue to see the star attraction of this wetland.
Ms. AMANDA PERDZOCK (Student, University of Wisconsin-Madison): The cypress tree is right there, it's next to those two dead ones. That's the lone cypress tree in our swamp.
HSU: In 430 acres of water once covered with trees, one living cypress bravely hanging on.
Andrea Hsu, NPR News, New Orleans.