This story is condensed from a broad multimedia presentation produced by the nonprofit newsrooms of The Lens and ProPublica. The full version is available athttp://projects.propublica.org/louisiana/

Online, you can track land loss from satellite and aerial images dating back, in some cases, to the 1930s and see the vast network of levees, oil and gas canals and other energy infrastructure.

Beyond the loss of actual land, the presentation looks at the cultural loss that Louisiana is suffering as our coast disappears. Pulitzer Prize-winning reporter Bob Marshall focuses on distinct areas of the coast that are edging toward oblivion and open water, complete with interactive maps and audio presentations.

Louisiana is drowning, quickly.

In just 80 years, 2,000 square miles of its coastal landscape have become open water, wiping places off maps, bringing the Gulf of Mexico to the back door of New Orleans and posing a lethal threat to an energy and shipping corridor vital to the nation’s economy.

And it’s going to get worse, even quicker.

Scientists now say one of the greatest environmental and economic disasters in the nation’s history is rushing toward a catastrophic conclusion, unabated and largely unnoticed.

At the rates that the sea is rising and land is sinking, National Oceanic and Atmospheric Administration scientists say that by 2100, the Gulf of Mexico could rise by as much as 4.3 feet across this landscape, which has an average elevation of about 3 feet. If that happens, everything unprotected by levees — most of southeast Louisiana — would be under water.

This land being lost is home to half of the country’s oil refineries, a matrix of pipelines that serve 90 percent of the nation’s offshore energy production and 30 percent of its total oil and gas supply. It is a port vital to 31 states. And for 2 million people, it’s simply home.

The crisis has been speeding along for decades, but at first, even those who work or play in the marshes didn’t appreciate the gradual changes. In an ecosystem covering thousands of square miles, a wider bayou here or a piece of eroded land there seemed insignificant.

Now residents are trying to deal with the shock of losing places they had known all their lives — fishing camps, cypress swamps, beachfronts, cattle pastures and backyards.

Fishing guide Ryan Lambert is one of them. When he started fishing out of Buras 34 years ago, he had to travel 6 miles to reach the Gulf of Mexico.

“Now it’s all open water,” Lambert said. “You can stand on the dock and see the Gulf.”

Two years ago, NOAA removed 31 bays and other features from the Buras charts. Some had been named by French explorers in the 1700s.

The people who knew this land when it was rich with wildlife and dotted with Spanish- and French-speaking villages are getting old. They say their grandchildren don’t understand what has been lost.

“I see what was,” said Lloyd “Wimpy” Serigne, who grew up in the fishing and trapping village of Delacroix, 20 miles southeast of New Orleans. “People today — like my nephew, he’s pretty young — he sees what is.”

If this trend is not reversed, a wetlands ecosystem that took nature 7,000 years to build will be destroyed in a human lifetime.

The story of how that happened is a tale of levees, oil wells and canals leading to destruction on a scale almost too big to comprehend — and perhaps too late to rebuild.

Engineering the river

For communities along its banks, the Mississippi River has always been an indispensable asset and the gravest of threats. The river connected their economies to the world, but its spring floods periodically breached locally built levees, washing away years of profits and scores of lives. Some towns were so dependent on the river, they simply got used to rebuilding.

That all changed with the Great Flood of 1927, when the Mississippi broke through levees in 145 places, flooding the midsection of the country from Illinois to New Orleans. Some 27,000 square miles went under as much as 30 feet of water, destroying 130,000 homes, leaving 600,000 people homeless and killing 500.

Congress passed the Flood Control Act of 1928, which ordered the U.S. Army Corps of Engineers to prevent such a flood from ever happening again. By the mid-1930s, the Corps had done its job, putting the river in a straitjacket of levees.

But the project that made the river safe for the communities along the river would eventually squeeze the life out of the river’s delta. The mud walls along the river sealed it off from the landscape sustained by its sediment.

If that were all we had done to the delta, scientists have said, the wetlands that existed in the 1930s could largely be intact today. The natural pace of sinking — scientists call it subsidence — would have been millimeters per year.

But we didn’t stop there. Just as those levees were built, a nascent oil and gas industry discovered plentiful reserves below. Oil companies dredged canals off natural waterways to transport rigs and crews. The canals averaged 13 to 16 feet deep and 140 to 150 feet wide — far larger than natural, twisting waterways.

Eventually, 50,000 wells were permitted in the coastal zone. Conservative estimates say 10,000 miles of canals were dredged to service them.

Such drilling and dredging happened so extensively in an area near Lafitte, it became known as the Texaco Canals.

“Once the oil companies come in and started dredging all the canals, everything just started falling apart,” said Joseph Bourgeois, 84, who grew up and still lives in the area.

From 1930 to 1990, as much as 16 percent of the wetlands was turned to open water as those canals were dredged. But as the U.S. Department of the Interior and many others have reported, the indirect damages far exceeded that:

Saltwater crept in, killing plants and trees whose roots held the soils together.

Shorelines crumbled without fresh sediment and dead plants, increasing the size of existing water bodies.

“Spoil levees” buried wetlands. When companies dredged canals, they dumped the removed soil alongside. The weight of the spoil on the soft, moist delta caused the adjacent marshes to sink.

All of this disrupted the delta’s natural circulatory system and led to the drowning of vast areas. Research has shown that land has sunk and wetlands have disappeared the most in the areas where canals were concentrated.

As the water expanded, people lived and worked on narrower and narrower slivers of land.

“There’s places where I had cattle pens, and built those pens … with a tractor that weighed 5,000 or 6,000 pounds,” said Earl Armstrong, a cattle rancher who grew up on the river 9 miles south of the nearest road. “Right now, we run through there with airboats.”

A U.S. Department of Interior report says oil and gas canals are ultimately responsible for 30 to 59 percent of coastal land loss.

More damage was done when drilling moved offshore in the late 1930s because companies needed pipelines to get oil and gas onshore. So they dug wider, deeper waterways to accommodate both the pipelines and the large ships that served the platforms.

Congress authorized the Corps of Engineers to dredge about 550 miles of navigation channels through the wetlands. The Department of Interior has estimated that those canals, averaging 12 to 15 feet deep and 150 to 500 feet wide, resulted in the loss of an additional 576 square miles of coastal land.

By 2000, coastal roads that had flooded only during major hurricanes were going underwater when high tides coincided with strong southerly winds. Islands and beaches that had been landmarks for lifetimes were gone, lakes had turned into bays, and bays had eaten through their borders to join the Gulf.

“It happened so fast, I could actually see the difference day to day, month to month,” said Lambert, the fishing guide in Buras.

Maps illustrating what the state will look like in 2100 under current projections show the bottom of Louisiana’s “boot” outline largely gone, replaced by a coast running practically straight east to west, starting just south of Baton Rouge.

Plan to rebuild, but no money

Similar predictions had been made for years, but it took Hurricane Katrina to finally galvanize the state Legislature, which pushed through a far-reaching coastal restoration plan in 2007.

The 50-year, $50 billion Master Plan for the Coast includes projects to build levees, pump sediment into sinking areas and build massive diversions on the river to reconnect it with the dying delta.

The state’s computer projections show that by 2060 — if projects are completed on schedule — more land could be built annually than is lost to the Gulf.

But there are three large caveats: The state is still searching for the full $50 billion; if sea-level rise is as bad as the worst-case scenario, the projects may not do the job; and building sediment diversions on the river, a key part of the land-building strategy, has never been done before.

Some of the money will come from an increased share of offshore oil and gas royalties, but many coastal advocates say the industry should pay a larger share.

Kyle Graham, executive director of the Louisiana Coastal Protection and Restoration Authority, said recently that the industry understands its liability for the crumbling coast and is discussing some kind of settlement.

“It’s very difficult to see a future in which that (such an agreement) isn’t there,” he said.

Graham has said current funding sources could keep the restoration plan on schedule only through 2019. He was blunt when talking about what would happen if more money doesn’t come through: There will be a smaller coast.

“There are various sizes of a sustainable coastal Louisiana,” he said. “And that could depend on how much our people are willing to put up for that.”

A vanishing culture

Trying to keep pace with the vanishing pieces of southeast Louisiana today is like chasing the sunset; it’s a race that never ends.

Signs of the impending death of this delta are there for any visitor to see.

Pelicans circle in confusion over nesting islands that have washed away since spring.

Pilings that held weekend camps surrounded by thick marshes a decade ago stand in open water — mute testimony to a vanishing culture.

Shrimpers push their wing nets in lagoons that were land five years ago.

The bare trunks of long-dead oaks rise from the marsh, tombstones marking the sinking of sediment-starved ridges.

“If you’re a young person, you think this is what it’s supposed to look like,” Lambert said. “Then when you’re old enough to know, it’s too late.”