Fighting Coastal Erosion
By Kathy Finn
The marshy areas that lie between the Gulf of Mexico and New Orleans provide a layer of protection from full-force blows by a powerful hurricanes. Those shallow areas are part of the larger shield that allows people to enjoy living in or visiting New Orleans, and could help to ensure that the city will be available for the enjoyment of future generations.
Decades of tidal pressure augmented by major storms like those that have recently struck the Louisiana coast have seriously eroded this fragile buffer zone. The result: New Orleans is closer to the Gulf of Mexico today than ever before.
Voters in the local area seem tuned in to the dangers that New Orleans’ proximity to the Gulf presents. In a June 2008 telephone poll of 500 registered voters in southeastern and south central Louisiana, 91 percent of those responding said they believe Louisiana’s wetlands need urgent attention. Most respondents said that a failure to restore damaged wetlands will result in more serious hurricane damage and significant harm to the area’s economy.
In the years since Hurricane Katrina blasted New Orleans, federal and state governments have committed billions of dollars to bolstering the system of levees and floodwalls that help keep water out of the city. During that time, however, little money has gone toward building up protection along the outer perimeter of the metropolitan area. That is about to change.
Louisiana has developed a conceptual plan for strengthening marshy areas that some scientists have termed the state’s “first line of defense” against a coastal storm surge. Last year, new federal legislation related to state sharing of tax revenues from the offshore oil industry ensured that substantial funding will be available to help Louisiana strengthen its coastal resources.
Just a few weeks before Hurricane Gustav crossed the state’s coastline, Gov. Bobby Jindal announced funding for $300 million worth of coastal protection projects. That money, along with funds previously committed, brought the total dollars currently available for coastal work to more than $1 billion.
“The amount of funding is pretty impressive,” says Robert Twilley, a professor of oceanography at Louisiana State University. “If you consider that, since 1992, spending has probably averaged about $35 million a year and here we’re talking about spending hundreds of millions — it’s mind-boggling, to be honest.”
Twilley, Associate Vice Chancellor of Research for LSU’s Coastal Sustainability Program, says the new funds are encouraging given the scope of work that’s needed. “The technical designs to get the projects constructed and the human resources to get this done are going to be tremendous,” he says.
One of the keys, Twilley says, is to make sure all the separate projects that receive funds fit into the overall goals of the larger region. “We still have time to connect the dots and make sure we’re moving toward a comprehensive system,” he says.
Ultimately, the system would include not only higher levees around populated areas and stronger floodwalls on drainage and navigation canals, but healthy, growing marshes near the coastline and some inland waterways and lakes.
One proposal central to the wetlands plan involves transporting tons of sediment from the Mississippi River delta to areas where the marshes are wearing thin. The idea includes building a pipeline that would run from the inner delta to areas such as lower Lafourche and Terrebonne parishes. As sediment is deposited into those areas, fresh water might be piped from the Atchafalaya River to “feed” the soil and encourage the growth of new marshes.
While the latest funding announcement pre-dates Hurricane Gustav, some say recent storms may put still greater support behind the concept of coastal restoration.
“Maybe this creates an opportunity to convey the urgency to the rest of the country,” says John Barry, a well-known writer and member of the Louisiana Coastal Protection and Restoration Authority.
Barry is the author of Rising Tide: The Great Mississippi Flood of 1927 and How it Changed America, which won the 1998 Francis Parkman Prize from the Society of American Historians. The book examined attempts by the U.S. Army Corps of Engineers to control the river’s flow and its potential for causing destruction.
Barry says it’s too soon to know how much coastal area may have been lost during recent storms, but he’s certain Hurricane Gustav, which pushed ashore through Terrebonne Bay 50 miles southwest of New Orleans, gobbled up more than marshes.
“It was not just wetlands. Some of it seemed as solid as any land you’d stand on,” he says. “But that part of the state was made vulnerable by [previous] land losses.”
It’s probably impossible to accurately quantify the value of land lost to coastal erosion, but at least one scientist has tried.
Robert Costanza, a former LSU professor who now runs the Gund Institute for Ecological Economics at the University of Vermont, recently co-authored a report that attempted to put a dollar value on such losses.
Measuring land via satellite and assigning values based on the land’s use and the size of nearby population, the study determined that Louisiana has lost $29 billion of flood protection benefits from the disappearance of 1,900 square miles of coastal wetlands during the past century.
More than $1 billion of wetlands benefits stemmed from the erosion of 80 square miles of wetlands during Hurricanes Katrina and Rita in 2005, the study found.
LSU’s Twilley says the state cannot fight such losses and protect a heavily populated area like New Orleans with levees alone.
“We have to add restoration as a major part of our protection system,” he says, “and it has to be aggressive.”