VENICE, La. – On an unseasonably warm winter morning, Earl Armstrong Jr. eases his airboat out of the slip, past a fishing crew hacking up a shark on the pier and a canal strung with hunting camps on stilts, into the broad waters of West Bay.

Armstrong, 67, kills the airboat’s engine and, looking around, remembers a place nothing like this one.

“You couldn’t travel through here before by boat,” he says, looking at the vast water broken by a couple of small, grassy islands. “Used to be woods here when I was little, that’s how thick it was. The grown-ups used to scare us by telling us there were tigers and lions up in here, but we came anyway.”

The sea took the forests and marshes of West Bay, leaving mostly open water, as it has along hundreds of square miles of Louisiana’s coastline over the last century. But now Louisiana may be about to embark on a highly ambitious project to keep its coast from slipping further underwater, and even restore some of it.

Eighty years ago, the Army Corps of Engineers built massive levees to protect New Orleans and its surroundings from the annual floods of the nation’s longest river. But the levees did their job too well, because they also blocked the silt that came downriver from the nation’s heartland and replenished the marshes like the one Armstrong remembers so well. That left the sinking Mississippi Delta defenseless against the slower but inexorable onslaught of rising seas brought about by climate change.

Now Louisiana is proposing to cut those levees in places to allow the Mississippi River’s silt to once again find its home, while building new dikes to protect coastal communities.

The 50-year, $50 billion draft master plan, which will be put before the state Legislature on March 26 and likely would need financial help from Washington, envisions sluices in the Mississippi River’s levees to allow sediment to flow into the delta again and restore land. It calls for the large-scale restoration of wetlands and erecting levees from Lake Charles in the west to New Orleans in the east.

But not everyone in coastal Louisiana is happy with the proposal.

Some towns will be outside the levees that protect from storm flooding. Oystermen and shrimpers fear the freshwater diversions from the Mississippi River into estuaries will ruin the saltwater fisheries there. The tough choices playing out in Louisiana now, the picking of winners and losers amid evolving science and budgetary constraints, are only a sign of what nearly every community facing climate change will have to wrestle with.

“The large-scale diversions they are so adamant about will ruin our fisheries, our livelihoods and our way of life,” said Tracy Kuhns, who runs an advocacy group of fishermen. She said that, as part of the plan, “something has to be sacrificed. We’re it.”

“The problem with the plan is that it relies too much on massive diversion of water,” said Kerry St. Pe, who heads a local environmental program. “That would be fine ecologically, but the problem is, people live here.”

Garret Graves, chairman of Louisiana’s Coastal Protection and Restoration Authority, which issued the draft plan, agrees that the plan cannot serve everyone’s interests: “People should have more protection, and we would like to give them more. We could say, ‘You’ll get flood protection, levee protection and a chicken in every pot.’ But the reality is, that’s not the truth.”

Louisiana’s coastline is the center of the offshore oil and gas industry, the entry point for thousands of ships plying the Mississippi River and the source of a substantial portion of the nation’s seafood. It’s the winter resort for millions of migratory birds, and home of a unique Cajun and Creole culture.

Yet almost any talk of the coast’s future is tinted with a sense of accelerating loss. In the central coast town of Chauvin, eighth-graders at Lacache Middle School say they feel lucky to grow up in a friendly, small town where they can easily hunt and fish. But in their short lifetimes, they have seen islands vanish and floodwaters regularly enter their yards. More than half say they will probably move away when they grow up.

“How can you stay when the place where you grew up in keeps getting washed away?” said Nick Cologne, 14. Hurricanes Katrina and Rita and the 2010 gulf oil spill further destroyed the tattered coastline and sounded a wake-up call to develop a workable plan.

Graves said Louisiana expected to get tens of billions of dollars in penalty money from BP and other companies connected to the gulf oil spill. The master plan’s funding also hinges on about $100 million it projects to get annually in oil and gas revenue, as well as a similar sum from a federal- and state-run coastal restoration program and other federal programs.

On Thursday, the U.S. Senate passed legislation that would direct 80 percent of Clean Water Act penalties connected with the spill to the gulf states.

The best example of what might happen in the bays south of New Orleans if the river is allowed to run can be found in a corner of West Bay. Earl Armstrong takes his boat toward a spot about 600 yards from the Mississippi River and beaches it on an island, one of four that have emerged in what was 5 feet of water thanks to a cut in the levee made in 2003.

Armstrong hops onto the sand with David Muth, Louisiana director for the National Wildlife Federation. The land began to build about two years ago, Armstrong said, and already, 3-foot willow saplings rise. Least sandpipers visiting from the Arctic skitter by the waterline. New cattails have been shorn by hungry geese and nutria rats. Scientists say the fresh water from the river will push shrimp and oyster fisheries farther out to sea, but not kill the industry.

“The planners, engineers and scientists are feeling their way through different aspects of the plan,” Muth said, “but the only thing we know for certain is that the river can build a delta.”