Tons of rocks intended for a protective barrier against the oil spill are on Mississippi River barges in Pointe à la Hache, La.

With oil hitting Barataria Bay, a vast estuary in southeast Louisiana that boasts one of the most productive fisheries in the country, local parish officials hatched a plan in May to save the fragile ecosystem: they would build rock dikes across several major tidal inlets between the bay and the Gulf of Mexico to block and then capture the oil.

Gov. Bobby Jindal of Louisiana supported the plan, and BP agreed to pay for the project, estimated to cost $30 million. By early June, about 100,000 tons of rock began being loaded onto barges on the Mississippi River for transport to the coast.

But over the weekend, the Army Corps of Engineers denied a permit for the project, citing environmental concerns, in particular the potential for the rock barriers to cause widespread erosion and the breaching of Barataria Bay’s existing barrier islands. The ruling echoed the sentiments of independent experts on coastal wetlands who had strongly objected to the plan.

Now the rock sits on 75 barges on the Mississippi River with no immediate use.

As the gulf oil spill enters its third month, Louisiana officials have grown increasingly enamored of large-scale engineering projects, like sand berms and rock walls, to keep the oil off their coast. But these projects, which demand the swift restructuring of eastern Louisiana’s dynamic and fragile coast, have brought the desires of state and local officials into sharp conflict not only with a complicated federal bureaucracy charged with protecting wetlands and estuaries, but also with an experienced and highly vocal community of local coastal scientists.

“They’re just sitting back criticizing,” said Deano Bonano, the emergency-preparedness director for Jefferson Parish, which borders Barataria Bay. “Where are they when it comes to protecting this bay?”

In a speech on Tuesday in New Orleans, Mr. Jindal said: “No one can convince us that rocks in the water are more dangerous than oil. That is absolutely ridiculous. The only people who believe that are the bureaucrats in Washington, D.C., who can’t see the oil, smell the oil or touch the oil."

The scientists insist the rock plan was misguided.

“There was very strong scientific backing for not doing this,” said Denise Reed, a wetlands specialist and director of the Pontchartrain Institute for Environmental Sciences in New Orleans. “This could really devastate our barrier shoreline, our first line of defense.”

For decades, the independent experts have worked hand-in-hand with the state and the federal government to save and restore Louisiana’s wetlands, which havelostroughly 1.2 million of acres to erosion since the 1930s and continue to disappear at the rate of 25 square miles every year.

It was these experts, along with their scientific peers in federal agencies like the National Oceanic and Atmospheric Administration and the Environmental Protection Agency, who offered the strongest opposition to the proposed rock barrier. Many of those critiques were included in supporting documents released by the Army Corps of Engineers before the official ruling was announced.

The scientists explained to the corps how narrowing the inlets with rock would set the stage for the breaching of existing barrier islands during the region’s frequent storms. They warned that damage to these islands — which have buffered the impact of major storms like Hurricane Katrina— would prove difficult to repair, perhaps impossible, and would most likely outstrip any benefit to the wetlands gained by stopping the oil with the rock barriers.

Having raised their voices in objection, these coastal experts now bristle at the accusation that they are out-of-touch academics or pencil-pushing bureaucrats, as state and local officials have charged.

“It’s really offensive, I think, and not fair, to call the scientific community bureaucrats,” said Dr. Ioannis Y. Georgiu, a professor of marine engineering at the University of New Orleans. “We are being demonized.”

Yet by siding with federal agencies blamed from the beginning of the spill for a slow-footed and chaotic response — and for which resentment still lingers over the failings of the federal response to Hurricane Katrina — these coastal scientists have made themselves easy targets for leaders eager to portray themselves as stopping at nothing in the fight against the oil. For these politicians, swifter action is crucial.

“You don’t wait weeks and weeks for studies and federal permits in the middle of a war,” Mr. Jindal, a Republican, said in a speech on July 2. “You do what you need to do as quickly as possible to protect your land and your people.”

The local scientists argue that quick-fix solutions are being sold to the public with little firm evidence that they will succeed, and with potentially dire side effects being minimized and ignored. A lack of engagement of the scientific community has also bred frustration. On the rock barrier plan, for instance, coastal experts were consulted only after a local engineering firm had drafted the permit application and orders had been placed for thousands of tons of rock to dump in the inlets.

“We’ve got such a coastal brain trust here, and they’re being left out in the cold,” said Dr. Len Bahr, a coastal scientist and former director of the Louisiana Office of Coastal Activities. “To me that’s just unconscionable.”

Some coastal experts concede that the scientific community has been more reactive than proactive regarding the spill, and has often waited to be consulted on solutions rather than offering up its own innovative ideas to keep oil off the coast, a criticism that local officials have echoed.

“We want to prevent the damage — we don’t want to clean it up,” Mr. Bonano, the emergency-preparedness director, said. “That’s the big difference between us and them.”

As charges fly back and forth, the prospect for a détente between the federal government and the coastal science community on the one hand and state and local officials on the other remains cloudy at best. Even with the rock plan soundly rejected by the Army Corps of Engineers, officials in Louisiana, from the governor’s office down, continue to argue that the plan to build the rock dikes was scientifically sound, and vow to carry on their fight to see it carried out.

Mr. Jindal said in a statement Tuesday that officials would resubmit the plan.

“We’ve made countless revisions,” said Garret Graves, the director of the governor’s Office of Coastal Activities. “We jumped through all these hoops to address their concerns, only to wait a month and be rejected.”

Mr. Jindal’s office has also said the governor will keep pressing for the rock barrier.

Coastal scientists, for their part, say they are ready to start investigating other options for stopping the movement of oil into the bay.

“I just wish the energy would go into looking for alternatives, not into just banging on the table,” Dr. Reed, of the Pontchartrain Institute, said. “Laying rock across passes is not the only way to stop the oil from getting into the marshes.”

NYT