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Louisiana tries mining mud to rebuild coast

A pilot project at the mouth of the Mississippi River shows how the hurricane-ravaged area may be able to rebuild its vanishing coast with fertile river bottom soil now dumped by dredges into the ocean.
To match feature ENVIRONMENT LOUISIANA
Mud dredged from the Mississippi River is pumped into wetlands to reverse the effects of coastal erosion near Pilottown, La, south of New Orleans.Lee Celano / Reuters
/ Source: Reuters

Louisiana is mining a new type of black gold: Mississippi River mud.

A pilot project at the river mouth shows how the hurricane-ravaged state may be able to rebuild its vanishing coast with fertile river bottom soil now dumped by dredges into the ocean.

Louisiana continuously clears the bottom of the Mississippi River to aid navigation, then dumps far offshore sediment that the river carries from tributaries in more than 30 states.

But recently a dredge clearing a few miles of the river moved the mud into nearby shallow water, rather than dumping it off the continental shelf in the Gulf of Mexico.

The result: New terra, though not quite firma.

At the spot where the dredged sediment is being dumped, a roughly half-mile-square patch of land has risen and a few wisps of green are struggling to take hold. The dredge has poured a combination of dark soil and river water through a pipeline to a monster version of a garden hose that releases the mess into the shallow brackish water.

Rebuilding such wetlands could help New Orleans absorb the blow of a future storm like Hurricane Katrina which devastated the city last year. Congress is considering bills that could pour a few billion dollars into coastal restoration in the state.

Louisiana’s predicament is urgent. The state, which has 30 percent of the continental U.S. coastal marshes, is losing a football-field-sized piece of land to salt water every 38 minutes, according to the America’s Wetland organization.

Human activity is largely responsible. Levees have prevented the Mississippi River from flooding and replenishing low-lying areas with silt and fresh water, while salt water has been invited in by canals cut through the marshes for logging, navigation and pipelines for the original black gold -- oil.

Louisianans have started to notice the loss of the buffer that the marshes provided. “A tropical storm used to be a nice breeze around here. Now everybody is flooded by it,” said Dean Blanchard, conservationist at the Barataria-Terrebonne National Estuary Program, a state-backed group that promotes wetland conservation.

Ancil Taylor, vice president at Bean Dredging, which started the pilot dredging project at Pilottown at the mouth of the Mississippi, argued that using pipelines for redirecting river sediment was cheap and easy and said similar projects had been done around the world for decades.

“You just all of a sudden start saving marsh,” he said. ”We’re a Louisiana company, and it breaks our heart to see these opportunities get away from us year after year.”

Other ideas, will any take hold?
But that’s not the only idea on how the state can tackle the problem. Louisiana’s history is studded with projects that never took hold. In most cases, after a few years of inactivity, a new studying process would begin.

Other ideas include building a new outlet branch of the Mississippi -- the $8.7 billion so-called Third Delta that would empty into some of the fastest-disappearing land, bringing soil and fresh water to the wetlands. Another idea calls for redirecting the outlet of the entire river. Finally there is the plan to build vast pipeline networks that would expand the current experiment using dredged sediment.

The Louisiana Department of Natural Resources commissioned a study on the Third Delta idea and alternatives, and the preliminary results show sediment pipelines would be relatively cheap and quick -- though the total price tag would be steep.

Pipeline projects across southwest Louisiana would cost between $9.4 billion and $31.7 billion over 50 years. The biggest version would actually expand Louisiana’s coast, which the Third Delta would not do over that time, at a cost per acre of up to $116,000 or a fifth of the Third Delta project, according to preliminary figures by engineers CH2M Hill.

Moreover, pipelines can start slow and build up, while the Third Delta is an all-or-nothing project, said department Deputy Secretary Randy Hanchey.

But he projected it would be 2008 before a state dredging project might begin. In the meantime, there is still debate in the state as to the best plan. Sydney Coffee, Gov. Kathleen Blanco’s adviser on coastal activity, said that the idea of diverting the mouth of the Mississippi was promising.

“We’ve got to think longterm sustainability,” she said.

Wary wetlands advocate
That lack of consensus is a warning sign for Kerry St. Pe, director of the Barataria-Terrebonne National Estuary Program and a longtime wetlands advocate who is pushing pipelines.

He recently showed off hundreds of acres of solid land built in the middle of a deteriorating wetlands with dredge material from a nearby port.

“We need to rebuild land, quickly. And a diversion of the Mississippi River is not going to do that,” he said.

St. Pe ticked off a half-dozen plans that were made and abandoned over the decades. His own group’s plan has been waiting for years, and while he is steadfast in its pursuit, he is not about to call victory based on recent interest in wetlands.

“When the estuary plan was created, there was a lot of momentum. I’d say more than now. It never happened,” he said.