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Louisiana's Coastal Wetlands Sinking

Environment: Global warming and riverbed engineering put New Orleans in peril.

August 11, 2002|MATT CRENSON | ASSOCIATED PRESS WRITER

ISLE DE JEAN CHARLES, La. — At the end of the road to Isle de Jean Charles, La., a patchwork of dusty green salt grass and sparkling blue water extends untouched to the horizon.

Stilt-legged egrets wing the sky or stand frozen in the grass. Occasionally, a fat mullet heaves itself out of the water and falls back with a gentle plop.

This beautiful vista is as sure a sign of ecological destruction as the scraped, barren soil of a Superfund site.

A few decades ago, Isle de Jean Charles was a patch of high ground in a sea of grassy marsh teeming with catfish and crawdads. Today, the small community is a true island, regularly flooded during storms and sometimes even at high tide. In a few years, it will be submerged completely.

Deme Naquin, 75, remembers paddling a flat-bottomed pirogue to school as a boy. Now he's getting ready to leave the only place he has ever called home. The U.S. government has offered to resettle the island's 270 residents because a new hurricane-protection plan leaves them outside the ramparts.

Some people want to stay. But Naquin and his family are ready to take the government's offer.

"Another hurricane and the road's going to be gone," says Chad Naquin, Deme's 29-year-old grandson. "It would be hard to leave, but in the long run, it would be the best thing."

A widely publicized government report recently predicted that sea-level rise caused by global warming could swallow sizable chunks of the coastal United States in the coming century. In Louisiana, that future is already here.

Up to 35 square miles of Louisiana's wetlands sink into the Gulf of Mexico each year. To date, an area the size of Rhode Island has been lost. In some places, the coastline has retreated 30 miles.

If scientists' global warming projections prove correct, virtually every state along the Atlantic and Gulf coasts will have problems similar to Louisiana's by the middle of the century. In a worst-case scenario, sea level would be 44 inches higher 50 years from now. If it is, 23,000 square miles of land along the Gulf and Atlantic coasts will disappear.

Low-lying cities such as Miami, Houston, Wilmington, N.C., and Charleston, S.C., will face many of the same problems that New Orleans grapples with today.

Beyond the United States, low-lying coastal countries such as the Netherlands, Bangladesh and the Bahamas stand to lose large swaths of territory.

"We're not going to be the only ones in the boat," says Al Naomi, a project manager in the New Orleans District of the U.S. Army Corps of Engineers. "We're just in the boat first."

People have been messing with the landscape of southern Louisiana for centuries, building ever-higher levees along the Mississippi and its tributaries to protect themselves from floods. For the last 50 years, they have even redirected the flow of the river itself.

The results have been catastrophic. South Louisiana requires a constant supply of mud and freshwater to keep itself above sea level, and channelizing the Mississippi River has deprived the landscape of that vital resource.

The Mississippi River literally built southern Louisiana, dropping countless tons of mud at the edge of the continent to form a delta. Over millenniums, the mud washed across the landscape during spring floods, settling in swamps and marshes to nourish plant growth. Every thousand years or so, the river changed course to fill in a nearby low spot.

Eventually the Mississippi built a broad swath of wetlands nearly 300 miles long. If you look at a map of the state, virtually everything south of Interstate 10 was dropped there by the river.

Now mud that would have settled into the swamps of the Atchafalaya or Barataria Bay shoots out into the Gulf of Mexico, never to be seen again. Meanwhile, the land is compacting, slowly turning to clay as it sinks under its own weight and squishes itself dry.

Sinking land due to mismanagement of the Mississippi River and rising sea level caused by global warming work in tandem, erasing Louisiana's coastal wetlands.

The loss of coastal wetlands threatens to devastate the state's fishing industry, worth $2.2 billion a year. Fish, crabs, shrimp and other animals rely on wetlands as a nursery, where their young can find plenty of food without exposing themselves to predators. By some calculations, Louisiana's wetlands are involved in producing as much as 40% of the seafood caught in the United States.

"The biological productivity of the Barataria and Terrebone basins alone dwarfs that of the Everglades, which our country is willing to spend billions to restore," Ted Falgout says.

Falgout is no rabid environmentalist, intent on saving every square inch of marsh no matter what the cost. As executive director of the Greater LaFourche Port Commission, he manages the country's largest transportation hub for offshore oil and gas drilling. There are 600 offshore drilling platforms within 40 miles of the port.

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