Anthony Caronia says that if he had known what the future held for Louisiana’s coast, he would not have built his family’s home on Avery Drive southeast of Slidell. But even after Hurricane Katrina washed away his house in 2005, he rebuilt on the land that backs up to marsh near Lake Pontchartrain and a large pond that draws waterfowl.

He believed at the time that improvements were going to be made to reduce the flooding risk in the neighborhood that’s dotted with houses and trailers on large parcels raised high on pilings and cinder-block columns.

But that didn’t happen, and now his property is even more vulnerable. In one recent storm, his backyard filled up with 6 feet of water, something that didn’t happen before. Caronia now can expect flooding with every storm, he said.

“There’s no coast anymore,” he said.

Avery Estates has become a big catch basin, he said, and he also thinks the construction of a massive shopping center on Fremaux Avenue made runoff in the area worse.

As sea levels rise, the problems faced by Caronia could get worse in the coming years, according to dire predictions in the latest edition of Louisiana’s Coastal Master Plan. The worst-case scenarios predicted by the plan, which was released last week, project more than 14 feet of flooding in the areas around the subdivision during significant storms.

The plan calls for measures aimed at reducing the danger, including a long-sought barrier across the Rigolets and funding to raise homes.

But as predictions become increasingly dire, the Coastal Protection and Restoration Authority now argues that for some parts of the state, the safest and most effective option may be to buy out properties in areas most likely to experience the worst flooding. The calculus is that even if it costs more than $1 billion to make those purchases, that would still be less than the damage they would sustain in the coming decades.

And having already rebuilt his house — paying for “every screw, nut and bolt” — Caronia said he would consider a buyout offer a godsend.

“They shouldn’t have allowed any of us to build here,’’ the tow-truck operator said. “It’s time to let it go.’’

More than 2,400 homes across the state could be eligible for such “voluntary acquisitions” under the latest version of the plan, and more than a third of those residences are, like Caronia’s home, in areas of St. Tammany Parish near the shores of Lake Pontchartrain.

“Our goal is to provide good, clear, hopefully honest information about what the risks are,” said Ben Haase, chief of the Planning and Research Division at CPRA. “It’s a community and individual’s decision what they do with that.”

Relocation is an extreme but increasingly common element in plans to deal with coastal flooding, particularly in areas threatened by rising sea levels and unprotected by man-made defenses.

For Louisiana, voluntary buyouts are not new. Similar and more wide-ranging plans were proposed in the 2012 version of the Master Plan. But that $10 billion recommendation, which essentially covered all of Louisiana’s coastal areas, was less well defined and was never implemented.

More concretely, the state secured about $52 million last year in a first-of-its-kind effort to move 27 families of the Biloxi-Chitimacha-Choctaw Native American tribe from the shrinking Isle de Jean Charles to safer ground.

The new coastal plan covers a wider area but is also more tightly focused than those previous efforts, targeting 32 areas for a $6 billion effort that would include elevations, buyouts and, in the case of commercial properties, floodproofing measures to make the buildings more secure.

About 26,600 properties would fall into one of those categories, and the report recommends the state simply try to purchase nearly a tenth of those.

The new version of the Master Plan is still a draft, and no specific properties have been identified for purchase or elevation. Those decisions would likely be made down the line, by parish officials, community members and ultimately the property owners interested in participating in the plan.

But the general guideline used in the proposal divides properties in the targeted areas into two categories.

First are those that would need to be elevated between 3 feet and 14 feet above the flooding a major storm could cause under the report's worst-case scenario, which includes rising sea levels, shrinking protective marshes and no actions by the state. For those properties, the best option could be to elevate the homes high enough to reduce the risk.

But raising a home more than 14 feet presents engineering challenges, particularly when hurricane winds are taken into account. So the coastal authority recommends offering to purchase properties that would need that much elevation; that could cost about $1.4 billion over the duration of the 50-year master plan.

“We’re looking to implement these sorts of projects, making it more of a streamlined, proactive way to do non-structural work without waiting for another disaster to occur,” said Melanie Saucier, a coastal resource scientist and manager with the CPRA.

The areas potentially eligible for buyouts are spread across the state. All 124 homes in an area around Delacroix would be eligible, as would hundreds of homes in Terrebonne Parish.

But St. Tammany Parish, with its low-lying coast and lack of major defenses, contains the bulk of the properties that could be purchased. About 890 homes there could be eligible for purchase.

Parish President Pat Brister said the number was surprising.

“It’s a hard message but one that you sometimes have to deliver,” she said. “It’s easy to say these structures need to be elevated or bought out, which means they’d be demolished, but these structures are full of families.”

Brister suggested the plan may be necessary in a parish where “repetitive losses,” properties that flood time and again, are mounting.

Parish and municipal officials have already been working to get grant money for similar efforts in St. Tammany.

The parish has put together its own list of properties that have flooded and whose owners have expressed interest in elevating or selling their homes. Parish Chief Administrative Officer Gina Campo estimated the cost of doing so would be in the hundreds of millions of dollars — something the parish chips away at as money becomes available.

“We’re trying to eat this elephant one bit at a time,” she said.

At the same time, the Coastal Master Plan also envisions more wide-ranging projects for the north shore. The most significant is a plan to put flood gates in the Rigolets to prevent storm surge from even entering Lake Pontchartrain, reducing the flood risk for all the communities that border the lake. More locally, the proposal includes funding for marsh creation and other projects in the parish.

Mayors in the coastal communities of Slidell and Mandeville said they welcome the idea of more funds for elevations, though both said they believe most buyouts would happen outside their city limits.

Mandeville Mayor Donald Villere said a study commissioned by the city estimated it would cost $35 million to raise the seawall along the lake by 2 feet. But that upgrade likely still would not protect a downtown area that faces massive flooding during storms, and the higher wall would not completely stop flooding elsewhere.

Raising homes, by contrast, provides a higher likelihood of preventing them from flooding and at a lower cost.

“Its something that we feel makes much more sense to do here in Mandeville because we know water’s going to come in; we can’t prevent it from coming in,” Villere said.

For now, local officials said they don’t expect any quick decisions.

“I think it’s still new and this is going to be long term. This is not going to be something in the next six months where we say these are the houses that need to be torn down,” Brister said. “It’ll be years. This was the starting point. Now we have started, it will be a process.”

In the meantime, the plan also serves as a reminder that St. Tammany remains vulnerable, even as it sometimes is seen as a refuge from the coastal issues farther to the south, where the coastline is receding every year.

“That’s one of the biggest benefits to us from an education standpoint,” Campo said. “We’re not considered one of the areas that needs the most attention, yet we had tens of thousands of flooded structures in Katrina. Heck, we had more than 1,000 flooded structures in March,” when river flooding struck many parts of the parish.

“The master plan bears out that we have billions of dollars in damages projected over the next 50 years, and quite frankly, people are going to be moving here. As it becomes more difficult to live in those lower-lying parishes, you’re going to see more people migrating here,” Campo said.

Follow Jeff Adelson on Twitter, @jadelson.​