Louisiana's Marshes Fight for Their Lives

By Cornelia Dean
The New York Times

Tuesday 15 November 2005

Shea Penland nosed his truck along a mud-covered street, past uprooted trees, cars leaning crazily on fences, torn-off roofs, and piles of ruined furniture, wallboard and shingles - the waterlogged evidence that Hurricane Katrina had been through the New Orleans suburb of Chalmette.

Twice, he turned to avoid streets blocked by brick houses apparently torn from their slab foundations and dumped blocks away. Finally, he spotted what he was seeking. "Look at that," he said, pointing to what looked like misshaped bowling balls tufted with long strands of yellow grass, seemingly thrown onto the porch and through the gaping doorway of a wrecked brick ranch house. "Marshballs."

For Dr. Penland, director of the Pontchartrain Institute for Environmental Studies at the University of New Orleans, these clumps of black mud knitted with roots and fronds are an alarming sight. The marshballs, some as large as a sofa, others as small as a shoebox, had floated from wetlands to the east. Dr. Penland says they are more evidence that after decades of human interference, the marshes of Louisiana are in deep, deep trouble.

"A healthy marsh is pretty resilient," he said. "A stressed marsh - storms will physically break the marsh down."

Now, as Louisiana struggles to recover from the storm, scientists like Dr. Penland are studying this marsh wreckage and the marshes themselves for clues to what ails them and how they might recover.

The questions are complicated, and the answers turn on a number of factors, including the region's geology, the ways people have engineered the flow of the Mississippi River, and the marsh-killing activities of the oil and gas industry. These issues inevitably lead to a far more difficult question: whether some marshlands, even inhabited marshlands, must be given up to the encroaching Gulf of Mexico.

Louisiana marshes are a nursery for many fish caught in the gulf, and they support the state's rich Cajun culture. Much of the nation's oil and gas passes through them. And though hurricane damage to New Orleans and other towns drew more attention, the storms "have caused a significant loss of wetlands and marshes and massive coastal erosion throughout the entire region," S. Jeffress Williams, a coastal scientist with the United States Geological Survey, told a Congressional hearing last month.

He said some marshy areas east of the Mississippi River lost 25 percent of their land areas in Hurricane Katrina, which came ashore more than 100 miles east of New Orleans. A strong hurricane that approached New Orleans from the south, along the path of the river, would do even more damage, he said.

Over the years, scores of scientists have struggled to determine the best way to approach Louisiana's vanishing wetlands. Last week, experts convened by the National Academy of Sciences reported their recommendations in an evaluation of the state's major marsh-restoration proposal.

Though they praised most of the plan's major components as scientifically sound, they said that it would reduce annual wetland loss only about 20 percent and that it was time to consider what areas could be preserved and what areas could not.

That attitude is anathema to much of the state's business and political establishment, according to Oliver Houck, a professor at the Tulane University School of Law who specializes in environmental issues.

He said a large obstacle to confronting wetland loss was what he called the "destroy and restore" philosophy, the longstanding practice of interfering with the marsh - for flood control, navigation, agriculture, oil or other gain - in hopes that engineering could restore it.

That, more or less, has been the history of this coastal region since Europeans made their homes here more than 300 years ago.

Coastal Louisiana is constructed of millenniums of mud, sediment carried by the Mississippi and deposited in its delta. The mud under the west side of New Orleans is about 200 feet thick; it compacts and sinks under its own weight. But when the river flowed naturally, regular floods carried silt from the heartland into the marshes, maintaining their elevation.

Levees and other flood-control and navigational efforts changed all that. Deprived of nourishing infusions of silt, the marshes began to sink, and this subsidence was accelerated when the petroleum industry began pumping out oil. According to the Geological Survey, since the 1930's Louisiana has lost more than 1,900 square miles of wetland, an area as large as Delaware.

Though the loss has slowed since the early 1980's, when a binge of canal-cutting and pipeline construction by the oil industry accelerated it to 40 square miles a year, it has not stopped. Dr. Penland, who has spent almost all of his career studying the coastal islands and marshes of Louisiana, estimates the annual loss at 12 square miles or so; others say 20 or more. The Geological Survey estimates that if things continue as they are, 700 square miles more will vanish by 2050.

"The whole surface is sinking," said Abby Sallenger, another coastal scientist with the agency. "It's almost changing before your eyes. It's grassland turning into open water, the ponds turn into lakes."

In theory, sea level rise from global climate change will only make things worse, although things in Louisiana are already so bad, Dr. Penland said, that "for us that's insignificant."

Many hope controlled diversions of river water into the marshes, one remedy included in the state plan, will help restore the natural balance. Others are doubtful.

Mr. Houck cited a project at Caernarvon, on a bend in the river south of Chalmette, where water is diverted into the marsh. After Hurricane Katrina, "half of that marsh was destroyed outright and half of what remains is iffy," he said. "A lot of it came off like hair ripped from someone's head" and probably ended up in Chalmette, he continued.

Also, Dr. Penland said, diversion projects small enough to be feasible and locally acceptable are dwarfed by the magnitude of the problem. For example, when scientists at Louisiana State used computer models to study a diversion proposal for Maurepas Swamp, between New Orleans and Baton Rouge, they said it would take 50 years to restore 5,000 to 10,000 acres to sustainability.

Efforts like that, however valuable, will not be enough, Dr. Penland said. "We have to not just mirror nature, we have to accelerate the way nature works. The solutions have to be proportional to the problem."

Much of the sediment that enters Mississippi River tributaries never makes it to Louisiana. By some estimates, 80 percent is trapped behind Missouri River dams. Plus, over the years the Louisiana economy has come to depend on the river's being constrained in its channel. Large infusions of fresh water would flood some homes and businesses and alter salt marsh habitats, with potentially harmful effects on commercially important species like oysters.

"We want the dirt without the water," Dr. Penland said. The only way to get it, he said, is dredging and then transporting the dredged material to the marsh that needs it, possibly through the kind of slurry technology used to move coal.

This technology has been in use for decades, but it remains to be seen if these kinds of measures can or will be applied in time. "There should be bolder, long-term projects for sediment delivery in areas in need than were put forth in the near-term plan," Robert G. Dean, a coastal engineer at the University of Florida who led the academy panel, said Wednesday at a news conference.

The panel also discussed making major changes in the state's coastal geography by diverting enough water flow to cause the river's Birdfoot Delta area to disintegrate, a process that would end up redistributing its sediment along the coast to the west. Or engineers could construct a "third delta" (the second being the delta of the Atchafalaya River), by diverting it at Donaldsonville, between New Orleans and Baton Rouge, and sending it toward the gulf.

Though large-scale projects like these offer potentially large benefits, the panel said, they also come with engineering challenges and likely opposition from property owners.

As Dr. Dean said Wednesday, progress will require "tiptoeing through the potential minefield of stakeholders." They should be involved in decisions as early as possible, scientists involved with the report said.

That will particularly be the case, they say, when it comes to deciding which settled areas can be preserved and which must be abandoned, an approach the academy implicitly endorsed even in the title of its report, "Drawing Louisiana's New Map."

Mr. Houck said it might be possible to "take major towns and ring them - Houma, Morgan City, Thibodaux, places like that." But, he went on, "if we aren't going to draw a line and try to protect every little town, we would have to do some serious people relocation, and that would humanely require compensation."

The alternative, he said, "is to build the largest levee system in the world" around the entire southern part of the state. "We'd cut right through the marsh, a Maginot Line - and about as effective, too," he said, referring to a French line of defense that infamously failed in World War II.

Where does this leave Louisiana? "Doing the things we can do now," said Dr. Penland, once again behind the wheel of his truck, but this time en route to Port Fourchon, a major oil installation on the coast. "What was proposed 20 years ago in the beginning of my career is coming around now."

He was heading south on Route 308, a two-lane strip that barely rises above the acres of salt-marsh grass and open water glimmering in the sun. Here and there, the leafless trunk of a dead oak tree rose from the grass. Dr. Penland said these gray skeletons signaled that this wetland was once a freshwater marsh dry enough for a tree to grow.

Every now and then, the truck would pass a house or trailer on stilts, marshballs lodged against its steps or under its porch. In places, piles of them had been pushed off the pavement onto the narrow shoulder. The beach at Port Fourchon, or what remains of it, is part of one of the major projects in the state plan. It lost what little remained of its sand in the hurricane, leaving a row of giant plasticized sandbags, perhaps 3 or 4 feet in diameter and 12 feet long, called "boudin" bags after the local sausage. Behind them, a sharp scarp marked the edge of a marsh, broken and buried under tons of grass and other plant debris.

Dr. Penland got out of the truck and looked around. "I have never seen such an extent of marsh wreckage," he said.

The Port Fourchon effort, which Dr. Penland is leading, involves pumping replacement sand onto the beach and pumping in additional sediment to restore the marsh behind. Similar sediment-pumping efforts in 2004 restored 50 acres of nearby wetland at a cost of about $300,000, Dr. Penland said. "That's cheap marsh."

But this kind of restoration works only when a marsh "just needs to be enhanced a bit," he said, and results are temporary. "There is no way you are going to fix any piece of coastal real estate forever," Dr. Penland said. "That's the hard fact you just have to face."