This story originally appeared in Hakai Magazine and is part of the Climate Desk collaboration. The creation story told by the Chitimacha people in Louisiana describes the world in its earliest days as a wide expanse of water. Then the Great Creator instructed crawfish to dive down and bring up a bit of mud. Geologists tell a similar tale, though their sculptor is the Mississippi River: For thousands of years, it dumped soils stolen off the continent into the Gulf of Mexico. Thus the river formed its delta, a vast and muddy and ever-changing landscape where the water once forked into many paths to the sea. These days, though, the river is largely restricted to one channel. Imprisoned within artificial levees, it’s no longer able to deposit its mud according to hydrological whim; instead, the river spits its sediment into the abyss of the deep sea. The consequences are grim: The existing mudscape is sinking. The ocean is rising. Over the past nine decades, more than 5,000 square kilometers of delta land in Louisiana has disappeared. Few places are going faster than Plaquemines Parish, which encompasses the muddy land along the river’s final 100 or so kilometers, where New Orleans’ exurbs give way to a smattering of rural communities. (A parish is the local equivalent of a county, a remnant of Louisiana’s French colonial history. ) One morning last summer, as we weave in his skiff through the parish’s marshland, Richie Blink tells me that the federal government has recently deleted 30-odd names from local nautical maps. Fleur Pond, Dry Cypress Bayou, Tom Loor Pass, Skipjack Bay: All have become undifferentiated, unlabeled expanses of open ocean. Now, the state government wants to open a gap in the levee to divert some of the river’s muddy water back into the marshes, allowing the river to resume its old task of construction. Work on the gap could begin in early 2023, assuming that the US Army Corps of Engineers, the federal agency that oversees waterway infrastructure, grants its official approval later this year. The Mid-Barataria Sediment Diversion—which is named for Barataria Bay, where the released river water will build a new “subdelta”—has been under discussion for years, but now, on the eve of destruction, it’s come under a firestorm of criticism from shrimpers worried about their livelihood; homeowners concerned about flooding; and environmentalists dismayed at the potential loss of bottlenose dolphins, a federally protected species. The diversion is intended to build new marshland, but it’s sometimes depicted as the latest assault on the region’s rural communities—which, according to critics, are about to be sacrificed again for the sake of nearby urban New Orleans. Blink, an ecotour guide, serves on the Plaquemines Parish council and is the sole member who has not voted to oppose the project. “We are facing these massive changes,” he tells me as the solid ground disappears behind us and we speed into open water. Either the diversion will alter the ecosystem, or the loss of land will. One way or another, the parish will have to do something new if it wants to survive. “We have to imagine this delta of the future,” he says. It strikes me, though, that we’ve often failed to imagine the delta of the present. Despite all the focus on land loss and land building, we rarely pause to discuss what we mean by land . And here in Louisiana, land—and who should control it—is a sometimes squishy idea. The Mississippi River is truly massive, combining three major tributaries that together drain 32 US states and two Canadian provinces, from Alberta to New York to New Mexico. Together, these various tributaries once sent as much as 290 million metric tons of dirt to the Gulf of Mexico each year, stacking it into an ever-growing lobe of land. Eventually, the lobe would grow so long that one of the side channels forking away from the river would become a tempting shortcut for the Mississippi. Lured away, the river jumped—or avulsed, in the parlance of geology—on a roughly millennial schedule, sending its torrent of water down one of these channels, building in a new direction. This process has yielded a branching network of overlapping sub-deltas that reach like splayed fingers into the Gulf of Mexico. Each sub-delta holds at its center a line of water, an active or abandoned channel of the Mississippi River. The highest ground, rarely more than a few meters above sea level, sits next to these channels; this is where the most mud has been deposited. These “ridges” can stretch for more than 150 kilometers, though they’re just a few kilometers wide. The modern Plaquemines Parish sub-delta began forming perhaps 750 years ago, and was still under construction when French explorers arrived in the late 17th century. The place seemed to consist “of nothing more than two narrow strips of land, about a musket shot in width,” one member of the crew wrote. Over the next century, French settlers marked the growth of the parish by noting how far the riverbank extended past a fort they’d built at the river’s mouth. A second type of landform stretches like webbing between the fingers: the marshland that makes up most of the coastal landscape. Here, the mud never stacked high enough to break the ocean surface, but it came close enough to allow marsh grass to root. It’s a world of rich organic soils, though rather unsteady: In places, mats of plants float atop the water, unattached to the soils below, so that if you step onto the grass, it will wobble and sink. The delta begins roughly 500 kilometers upstream of the river’s mouth, and as of 1930, covered nearly 20,000 square kilometers—an area almost the size of New Jersey. The water running through the marshes is fresh inland and grows saltier closer to the sea. Many species—blue crabs, white shrimp—move across this gradient throughout their life cycles, and the marsh, as a result, offers an abundance of life. The ever-shifting landscape makes research difficult, but evidence suggests that people arrived on the ridges even as they were forming, perhaps to establish short-term hunting and fishing camps amid the new marsh. The colonial records are somewhat sparse when it comes to Indigenous life within the delta. The first French explorers noted various groups, including the Quinipissa, the Yakni-Chito, the Washa, the Chawasha, and the Chitimacha. Archaeological evidence suggests that at the time of contact, people lived in small villages mostly focused on gathering fish and other wetland resources. The delta was an important crossroads, linking coastal travelers with upriver communities; French explorers noted that so many canoes had been dragged across one ridge-top portage that they had produced a “rather good road. ” The Choctaw, one of the larger tribes on the land that would become the US South, called this spot, or perhaps the whole delta, Bulbancha—the place of other languages. The arrival of European settlers brought disease and slave raids and warfare, and by the time the French began keeping solid records in the 18th century, some Indigenous nations had disappeared, the survivors integrating with neighboring tribes. Some groups slipped into corners of the delta rarely traversed by colonists. People from various villages and traditions settled together, and today the US government refuses to officially recognize some of these groups as tribes, since there is no written record of their beginnings. European settlers seemed not to know what to make of this landscape, which was far larger and muddier than any delta they’d known. One 18th-century French cartographer depicted a large swath as a blank mass, noting it as “trembling land and swamp”; 120 years later, a surveyor from the US Army made his opinion clearer by pointedly declining to enumerate the marshland’s features. A list of the “multitudinous islands and sheets of water would add nothing” to his description of Plaquemines Parish, the surveyor wrote. The marshes become something of a no man’s land—or perhaps it’s better to say an every person’s land. In the late 18th century, a group of runaways escaping slavery set up an armed camp in the marsh to the east of New Orleans that could be accessed only by wading through chest-deep water, pushing through the reeds. The Maroons, as they were known, lived alongside Filipino immigrants, who occupied stilt villages three meters above the water and processed dried shrimp by dancing atop the shells. Immigrants from the Canary Islands settled nearby, too. Historians estimate that at the dawn of the 20th century, 150,000 people lived in 200 communities scattered across the delta’s marshlands. These marsh dwellers made their living by fishing, mostly, sometimes trapping raccoons and muskrats for furs. Then, in the 1920s, oil was discovered beneath the marshes. Surveyors began to trudge through, sinking to their chests in the soft soils, assessing the prospects of this land that was barely land. Some Indigenous residents, unable to read English, signed papers they believed would affirm their ownership. Instead, they were quitting their claims. Today, 90 percent of southern Louisiana is corporate-owned. In places, permanent homes are now outnumbered by “fishing camps”—a catch-all term for coastal vacation homes, though one that implies a false rusticity. Camps often have modern amenities, and some feature lavish architecture. These camps tend to be clustered in marinas, often just beyond the point where the ridge drops away into marsh. Most modern settlement has occurred atop the ridges themselves, which feature the only viable tracts of farmland in the delta. New Orleans was founded in 1718 atop the ridge that runs alongside the current channel of the Mississippi, 150 kilometers upstream of the river’s mouth. The city’s earliest residents found that even this land was precarious. Within the settlement’s first year, the river’s spring rise sent water streaming through the half-finished buildings. The colony’s commander general ordered the construction of a levee, a mound of earth, knee-high, piled along the edge of the river. It was the first small step in a long quest to tame the Mississippi. Other levees were built along the river through the decades until they merged into a single entity that stretches thousands of kilometers north—well beyond the top of the delta all the way into southern Missouri, where the Mississippi’s big tributaries join together. By the 20th century, engineers were closing the gaps in the levee that had allowed water to pour out into the delta’s forking streams. They presumed this would reduce flooding by helping the water speed toward the sea. In the 1950s, engineers confronted another problem: The river was beginning to avulse once more. More and more of its water was pouring into the Atchafalaya River, the last unclosed outlet, aside from the river’s mouth. Scientists realized the Atchafalaya could soon steal the Mississippi’s might; the final 500 kilometers of the river would shrivel into a brackish creek—a big problem, given that New Orleans relies on the river for drinking water. A set of gates was installed to halt that jump. By then, there had been a few cries of alarm about disappearing land. A note in National Geographic in 1897 indicated that an old Spanish magazine at the river’s mouth had sunk roughly 30 centimeters over 20 years. In the 1940s, a writer noted that the back edges of many plantations built along the riverbanks were slumping into the water. Both accounts blamed the levee for the problem. The state government investigated land loss in the 1950s and found the ocean was creeping inland by as much as 19 meters per year. But the focus of the survey was more economic than scientific—the state government was in a dispute with the federal government over where the offshore seabed, and its lucrative oil deposits, turned into federal property—and few ecologists expressed alarm. The prevailing wisdom seemed to be that, on the whole, the delta would survive. After all, it had already persisted for thousands of years. Then, in the 1960s, Texas officials asked for the Mississippi’s water to be diverted west, toward that state’s drought-stricken plains. Since this would reduce the river’s flow to the coast, a team of researchers at Louisiana State University (LSU) began to investigate potential side effects. The team rediscovered the ongoing crisis of land loss. Once more, scientists blamed levees, though they also acknowledged the damage caused by oil companies. Companies had dredged canals to reach sites where they drilled for oil and to clear paths for pipelines. These canals—which in 1970, the LSU scientists described as already “innumerable”—altered water circulation, bringing salt water into freshwater ecosystems, poisoning the plants whose roots held the soil together. Subsequent studies have underlined their dangers: one 1997 study found that each hectare dredged caused another 2. 85 hectares of marsh to disappear. The LSU report, though, became best known for its proposed solution, which focused on counteracting levees. The authors suggested that some water and mud be diverted out of the Mississippi, back into the marshland. Let the river resume the work it had been doing for thousands of years, before it was restrained, in other words. It’s an idea that has captivated engineers and ecologists ever since. To test the concept, scientists began to cut through the natural banks near the river’s mouth. (Because the land near the mouth was so irremediably swampy, levees were never built along the river’s last few dozen kilometers. ) By the end of the 1980s, the US Army Corps of Engineers was working on a more substantial “diversion” at a site called Caernarvon, just upstream of Plaquemines Parish: Here, a set of gates allows water to pass through a tunnel beneath the levee and into the marsh. The project’s official purpose is to supply fresh water to the marsh’s delicate plants. When construction began, though, local newspapers described the project as a potential conduit for sediment—not just a way to preserve marsh, then, but also to rebuild it. Indeed, just a few years after the gates were opened in 1991, hundreds of hectares of new marsh had formed. By then, the federal government had begun to fund other restoration projects, too. Soil dredged out of the river was dumped along the coastline; rock walls were built along eroding beaches; new sand was added to the barrier islands that sit just beyond the delta; a second small freshwater diversion was built. But those efforts weren’t enough to do what many believed was necessary: to build the kind of large diversions that could construct entire sub-deltas. Then, in late 2005, Hurricane Katrina walloped New Orleans, kicking up enough gulf water to submerge much of the ridge-top city. The missing marshland, many scientists pointed out, could have absorbed some of the power of the storm-driven waves, serving as a kind of hurricane speed bump. Ecologica