Published: August 2007

New Orleans

Two people hugging.

New Orleans: A Perilous Future

The sinking city faces rising seas and stronger hurricanes, protected only by dwindling wetlands and flawed levees. Yet people are trickling back to the place they call home, rebuilding in harm’s way.

By Joel K. Bourne, Jr.
National Geographic staff
Photograph by Tyrone Turner

Hurricane Katrina, the costliest natural disaster in United States history, was also a warning shot. Right after the tragedy, many people expressed a defiant resolve to rebuild the city. But among engineers and experts, that resolve is giving way to a growing awareness that another such disaster is inevitable, and nothing short of a massive and endless national commitment can prevent it.

Located in one of the lowest spots in the United States, the Big Easy is already as much as 17 feet (five meters) below sea level in places, and it continues to sink, by up to an inch (2.5 centimeters) a year. Upstream dams and levees built to tame Mississippi River floods and ease shipping have starved the delta downstream of sediments and nutrients, causing wetlands that once buffered the city against storm-driven seas to sink beneath the waves. Louisiana has lost 1,900 square miles (4,900 square kilometers) of coastal lands since the 1930s; Katrina and Hurricane Rita together took out 217 square miles (562 square kilometers), putting the city that much closer to the open Gulf. Most ominous of all, global warming is raising the Gulf faster than at any time since the last ice age thawed. Sea level could rise several feet over the next century. Even before then, hurricanes may draw ever more energy from warming seas and grow stronger and more frequent.

And the city’s defenses are down. Despite having spent a billion dollars already, the U.S. Army Corps of Engineers now estimates it will take until after 2010 to strengthen the levee system enough to withstand a 1-in-100-year storm, roughly the size of Category 3 Katrina. It would take decades more to protect the Big Easy from the truly Big One, a Category 4 or 5—if engineers can agree on how to do that and if Congress agrees to foot the almost unimaginable bill. For now, even a modest, Category 2 storm could reflood the city.

The long odds led Robert Giegengack, a geologist at the University of Pennsylvania, to tell policymakers a few months after the storm that the wealthiest, most technologically advanced nation on the globe was helpless to prevent another Katrina: “We simply lack the capacity to protect New Orleans.” He recommended selling the French Quarter to Disney, moving the port 150 miles (240 kilometers) upstream, and abandoning one of the most historic and culturally significant cities in the nation. Others have suggested rebuilding it as a smaller, safer enclave on higher ground.

But history, politics, and love of home are powerful forces in the old river town. Instead of rebuilding smarter or surrendering, New Orleans is doing what it has always done after such disasters: bumping up the levees just a little higher, rebuilding the same flood-prone houses back in the same low spots, and praying that hurricanes hit elsewhere. Some former New Orleanians may have had enough. More than a third of the city’s pre-Katrina population has yet to return. Those who have face deserted neighborhoods, surging crime, skyrocketing insurance, and a tangle of red tape—simply to rebuild in harm’s way.

If Paris, as Hemingway said, is a movable feast, then New Orleans has always been a floating one. Born amid willow and cypress swamps atop squishy delta soils, the city originally perched on the high ground formed by over-wash deposits from annual river floods. Jean-Baptiste Le Moyne, Sieur de Bienville, actually had to wait for the water to recede before he could plant the French flag in 1718. A flood destroyed the village the year after he founded it, and hurricanes wiped it off the map in 1722 and again a year later. In its 289-year history, major hurricanes or river floods have put the city under 27 times, about once every 11 years. Each time, the fractious French, Spanish, blacks, Creoles, and Cajuns raised the levees and rebuilt.

Until the 20th century, they kept to the high ground along the Mississippi River and on three nearby rises—the Metairie, Gentilly, and Esplanade Ridges. But in the early 1900s a brilliant city engineer, A. Baldwin Wood, invented massive pumps, up to 14 feet (four meters) in diameter, that were used to drain the great cypress “backswamp.” The booming metropolis began spilling north toward Lake Pontchartrain. As the swamp soils dried, they shrank and compacted, slumping below sea level. In every flood since, the newer, lower neighborhoods suffered the most as the waters found their former haunts in the old swamp.

The great tragedy of Katrina is that the hard lessons learned in those earlier storms were blithely forgotten by all. After the great Mississippi River flood of 1927 wreaked havoc all along its course and came within a few feet of spilling over the river levees and inundating New Orleans, the growing city clamored for additional protection. Over the coming decades, the federal government erected a vast network of levees and spillways along the river and around the city, while giant new dams along the Missouri—the Mississippi’s longest tributary—ponded water all the way to South Dakota. The system was billed as a triumph of engineering over nature.

Yet Gilbert F. White, considered the “father of floodplain management,” came to a far different conclusion, one that Katrina drove home with a vengeance. As a young University of Chicago geographer, White had studied the delta after the 1927 disaster and realized that much of the suffering could have been avoided. “Floods are ‘acts of God,’” he wrote in 1942, “but flood losses are largely acts of man.” White and his colleagues argued that dams, levees, and other flood protections may actually increase flood losses because they spur new development in the floodplain, which incurs catastrophic losses when man-made flood protections fail. The phenomenon came to be known as the “levee effect.”

Nowhere was White’s advice more gleefully flouted than in the Lake Pontchartrain and Vicinity Hurricane Protection Project—the 125-mile-long (200 kilometers) system of levees and gates built by the U.S. Army Corps of Engineers to protect the city after Hurricane Betsy ravaged it in 1965. City planners and developers applauded as the corps not only strengthened existing levees around the city but also threw new levees far and wide, enclosing thousands of acres of undeveloped wetlands lining the new I-10 corridor. In fact, 79 percent of the estimated benefits that the corps initially used to justify the cost of the project came from the future development of those wetlands. Within a decade, Jefferson Parish had built 47,000 new housing units—modern-day Metairie and Kenner—while Orleans Parish added another 29,000 units, mostly in New Orleans East.

“It was basically a development scheme,” says Oliver Houck, a Tulane professor of environmental law who has fought other corps projects. “They put it around New Orleans East, and the developers laughed all the way to the bank.”

From its inception, the project was beset with technical problems, litigation, and political tinkering. What was supposed to be built in 13 years for 85 million dollars became a never ending 740-million-dollar project that was still ten years from completion when Katrina hit. The Government Accountability Office—the watchdog of Congress—had a field day, regularly criticizing the corps for cost overruns and delays.

Early on, experts warned about serious flaws in the system. In 1984 Wilson Shaffer, a storm-surge modeler at the National Weather Service, told the corps that the Standard Project Hurricane, the hypothetical storm against which engineers tested their levee designs, was too small to represent the true threat. Stronger storms—such as the Category 5 Hurricane Camille, which slammed into Mississippi four years after Betsy—could easily overtop the system and flood the city, Shaffer said. “There are no high areas near the city that wouldn’t flood in extreme cases,” he wrote. “High ground is several tens of miles away. Evacuation routes are limited. ... Imagine, if you can, the massive destruction and loss of life.”

The corps rejected these warnings. Protection against these “rare” events, the corps deemed, would be “prohibitively expensive,” a conclusion seconded by the Orleans Levee District, the local flood-protection authority. The corps also dismissed another, longer range threat, summed up in a graph made by John S. Hoffman of the Environmental Protection Agency: rising sea level because of global warming. By 2100, Hoffman projected, the sea could rise “at least two feet (0.6 meters), with a more likely amount as 3.7 feet (1.1 meters). A rise as high as 12.6 feet (3.8 meters) cannot be ruled out.” The corps responded: “Given the uncertainty of projections of sea level changes, an attempt to accommodate such changes in the design of the project ... would represent a very poor use of funds.”

“Locals wanted the cheapest possible protection system,” says Oliver Houck. “But it wasn’t cheap, it was just badly built.”

The floodwalls along the city’s major drainage canals were a classic example of the shortcomings. The corps didn’t want to build most of them. Initially it planned to block storm surge with giant barriers across the eastern inlets of Lake Pontchartrain, beef up the levees along the southern lakeshore, and erect massive floodgates to keep high water out of the canals. Environmental groups, concerned about impacts on the lake and its wetlands, blocked the plan in court. The corps dropped the barriers and switched to a system that would rely on higher lake levees and floodgates. State and local officials—who were required to pick up nearly a third of the ballooning tab—balked at the cost of the gates. They also feared that closing the gates could actually cause flooding, as rainwater piled up in the canals. City leaders pushed instead for floodwalls along the canals. The groups remained at loggerheads until 1992, when Congress passed a water resources act that forced the corps to do it the city’s way.

Foundation problems plagued the levees and floodwalls from day one. A contractor building the 17th Street Canal floodwalls in the mid-1990s actually tried to sue the corps for more money as the mucky soils drove up costs. The underlying sheet piles—steel panels driven into the ground to form a barrier—were shifting and pushing the concrete walls on top out of line.

Katrina, alas, exposed these weak underpinnings. When the storm drove floodwaters to within four feet (1.2 meters) of the top, the walls deflected backward, opening a crack at their base. Water poured in, found a thin layer of clay as slick as jelly, and forced nearly 450 feet (137 meters) of levee into Orleans Parish. On the London Avenue Canal, sandy soils led to similar blowouts. Floodwall failure let in nearly 80 percent of the water that flooded the central part of the city. “Just ten million dollars more spent on sampling and foundation investigation, and the system wouldn’t have failed,” says engineer J. David Rogers, who investigated the breaches with a team from the University of California, Berkeley. “It didn’t come within a country mile of the design load.”

And that was just a start. In the year after Katrina, two independent investigations and the corps’s own 25-million-dollar study painted a detailed picture of flaws in the planning, design, and construction of the levee system. The corps, in its defense, says it was hamstrung by a political process that tied the project to what the local sponsor wanted and, more important, could afford. “Basically, you had political influence on significant engineering decisions,” says the corps’s project manager for the hurricane protection system, Al Naomi. “We went from fighting surge at the Rigolets and Chef Menteur passes, to fighting surge at the lakefront, to fighting surge in the heart of a major American city. Failure at the Rigolets would have had far less consequences than failure on 17th Street.”

Taller, stronger floodwalls now glisten in the breaches, their clean white concrete contrasting starkly with the still ruined neighborhoods behind them, while massive new black floodgates are poised to close the canals at the lakefront. The rebuilt hurricane protection system gives returning New Orleanians some sense of security. But the corps has yet to fix what many see as the weakest link in the system, the 76-mile (122 kilometers) ship channel called the Mississippi River Gulf Outlet—Mr. Go to the locals—which the corps dug east of town in the late 1950s and early 1960s.

On a steamy summer afternoon with squalls in the offing, coastal scientists Paul Kemp of Louisiana State University and John Lopez of the Lake Pontchartrain Basin Foundation set out by boat to inspect the “funnel,” formed east of town by the levees lining the MRGO and another channel that converges with it, the Gulf Intracoastal Waterway. Computer models run by Kemp’s colleagues at LSU show the funnel raised Katrina’s massive surge by more than three feet in the Industrial Canal, overtopping and destroying floodwalls protecting the Lower Ninth Ward. Farther east, the storm surge hammered through more than eight miles (13 kilometers) of the MRGO levees, which in turn wiped out much of St. Bernard Parish.

St. Bernard residents had been clamoring for years for the corps to close the little-used channel they call the “hurricane highway.” Touted as a shortcut to the port for ocean freighters, the channel instead destroyed tens of thousands of acres of wetlands. It brought in salt water that killed marsh plants, while the wakes of the few ships eroded the banks of the channel, widening it from 500 feet (150 meters) to almost a half mile (one kilometer) in places. One lesson of Katrina is simple, says Lopez: Close MRGO.

The corps says it now intends to do so. But when or how the channel might be shut down is anyone’s guess. Congress has yet to give a green light. “If we don’t close MRGO,” says Lopez, “it might be time to do what my wife says and move to Kansas.”

Though the corps denies that the channel amplified Katrina’s surge, everyone agrees that its levees—St. Bernard’s primary hurricane defense—failed miserably. The corps insists the structures simply weren’t high enough to withstand Katrina’s 17 feet (five meters) of surge and six-foot (two meters) waves. But at many of the breaches, the levees were built of weak sand and shell dredged from the canal itself. Kemp believes the shell-sand sections began to collapse as soon as the waves started breaking on them, long before the main surge hit. He also notes that where these levees were fronted by intact wetlands or trees, they survived. Where they ended directly in the water, they failed.

Old ways die hard in the bayou. Even after the dramatic failure of the shell sand in the levees, independent investigators found corps contractors using the same material to rebuild them. Only after the discovery was made public did the corps barge in yellowish clay from Mississippi to cap the levees. And parts of the new structures still have no buffer against erosion.

Kemp points to a new section of bare levee right next to the channel and shakes his head. “This is a recipe for disaster,” he mutters. “The waves are going to break right on that thing. If a big storm comes in here this year, it’s gone.” Even sections of the levees newly capped with clay are already eroding from rainfall, Kemp says. In fact, during a recent inspection, engineering professor Bob Bea, who helped lead the UC Berkeley team that investigated the levee failures, found multiple chinks in the city’s hurricane armor, from newly eroded levees along MRGO to Katrina-battered floodwalls that had not been repaired.

“When you start thinking about long-term protection, it doesn’t give me any confidence,” says Bea, a former resident of New Orleans who actually lost his home during Hurricane Betsy. “The system is ratty, shot full of defects. My advice for the people in low-lying areas: I wouldn’t start rebuilding my life there.”

Yet many are doing just that, regardless of what the experts say, with a typical New Orleans cocktail of denial, faith in the levees, and 100-proof love of home. Three months after the storm, when much of the city still lay in ruins, the mere suggestion by a blue-ribbon panel of planners from the Urban Land Institute to hold off rebuilding the lowest areas set off a howl of protests. Mayor C. Ray Nagin, who was in a tight election race at the time, dropped the notion of “shrinking the footprint” like a hot beignet, as did his opponent, Lieutenant Governor Mitch Landrieu. The mayor, however, fell short of promising every neighborhood city services.

To make matters even more confusing, the federal government declared it would offer flood insurance for most new or substantially rebuilt houses only if they were raised by several feet. Yet the city government granted exemptions to many returning homeowners, grandfathering their houses at their prior elevations. The result has been an unplanned patchwork recovery, with some people raising their homes to protect against floods and others building right back where they were in the lowest sections of the city.

Even after the massive engineering breakdown during Katrina, Matt McBride believes people can live safely at the bottom of the New Orleans bowl in a neighborhood called Broadmoor, which dips as much as ten feet (three meters) below sea level. Streets of colorful “shotguns” and raised basement houses, many built in the 1920s and 1930s, have put Broadmoor on the National Register of Historic Places. Its less glorious claim to fame is that for much of its history the place was prone to flooding in any heavy downpour, resulting in one of the highest rates of repetitive flood losses in the nation. In one section of Broadmoor, homeowners with multiple losses have filed an average of six flood claims each.

A 1995 flood following a rainstorm that dumped 14 inches (35 centimeters) on the neighborhood led to a multimillion-dollar drainage improvement project, completed in 2002, that drastically decreased flooding. Even during Katrina, with its 12 inches (30 centimeters) of rainfall, Broadmoor only flooded to the lawns and was pumped dry before the levees breached and the real flooding began. It was proof of what good engineering can do, says McBride, himself an engineer. “You can’t design a perfectly flood-proof home,” he says. “But if you get adequate levee protection and adequate drainage, I think people will return.”

Keysha Finley didn’t wait for the levees to be fixed. Just nine months before the storm, Finley had moved into a new four-bedroom brick house off Bullard Avenue, in one of the tonier neighborhoods of New Orleans East. Singer Aaron Neville lived in the posh Eastover subdivision nearby. Though most media attention has focused on the working-class Lower Ninth Ward, the damage was just as bad in New Orleans East, a bastion of middle- and upper-class black flight from crime and failing schools in the inner city. It’s also one of the lowest sections of the city, with some areas more than ten feet (three meters) below sea level.

Less than a year after the flood, Finley was back. Her kitchen, where four feet (1.2 meters) of muddy water sloshed for weeks, is now filled with warm Mediterranean colors and has a new tile floor. Is she concerned about the low elevation? “It was never a consideration,” she says. “Before we bought, we asked the neighbors if it ever flooded. They said never.”

Nearby houses remained boarded up and empty for months, but now the neighbors are rebuilding, reassuring Finley that she and her husband were right to return. “I know things happen wherever you go. You can’t run from them,” she says. But the months of stress have taken their toll. “If it happens again, I won’t come back. I don’t think I could go through this again.”

The die-hard refusal to give up on home persists in the Lower Ninth Ward, where many houses had been in families for decades. Caught by a pincer of tidal waves coming from the blown-out levees to the east and the blown-out floodwalls of the Industrial Canal to the west, the black working-class neighborhood stewed in floodwaters for four weeks. Residents were not allowed to move back for another two months, to the utter dismay of Tanya Harris, an organizer for the community-rights group ACORN. Harris’s family had lived for 60 years in the hardest hit section, north of Claiborne Avenue, what she calls “way back-a-town.”

“My neighborhood was an extension of the inside of my house,” she says, driving over the rusty drawbridge over the Industrial Canal. “When I turned off Claiborne Avenue after work, it would take me 20 minutes to drive the last ten blocks home because I’ve got to wave to Aunt May and 20 other people. I’d complain about it, but I loved it.”

Aunt May left after the storm, as did the kids who once played in the streets. The last ten blocks to Harris’s home remain the same blur of destruction that blazed over television screens across the nation, with most houses abandoned or destroyed. Her house survived, a one-story yellow brick affair with red shutters. Twenty months after the storm, her renovations were nearly complete, and she hoped to move in soon.

The tortoise pace of repairing fractured sewer and water lines in the Lower Ninth originally fed suspicions that the city would take the Urban Land Institute’s advice and redevelop the neighborhood with higher income homes and condos near the river and green space way back-a-town, replacing the derelict houses. But thanks largely to the efforts of Harris and ACORN, the city in March included the Lower Ninth in its rebuilding plan, which provides seed money for redevelopment. In fact, one of the first two new houses built in the neighborhood belongs to Harris’s grandmother, Josephine Butler, the five-foot-tall (1.5 meters), 85-year-old matriarch of her clan. “Nobody,” says Harris, “not Ray Nagin, not George Bush, is going to tell her what to do.”

The reality remains daunting for those trying to rebuild, or trying to decide whether to come back at all. The risk of catastrophic flooding is rising year by year, with no end in sight—in no small part because the city is sinking.

Even before it was covered by millions of tons of floodwater, New Orleans had sunk well below sea level, because of the draining and compacting of the backswamp and the pumping of groundwater. According to the latest satellite measurements, the city continues to sink at around two-tenths of an inch (0.5 centimeters) each year. The rate is faster in Lakeview and fastest of all in neighborhoods to the east and west. In St. Bernard Parish, subsidence tops out at nearly an inch (2.5 centimeters) a year. Some sections of the MRGO levees have sunk up to four feet (1.2 meters) since they were built, according to Roy Dokka, an LSU geologist who co-authored the satellite study, and Katrina breached many of the low spots.

“This is a place where people shouldn’t be living, yet we’re here,” says Dokka. “But subsidence isn’t going to kill people. It’s the ever increasing vulnerability to storm surges and our inability to prepare for them.”

Sinking is only part of the city’s elevation challenge. Over the thousands of years when the delta beneath the city was being formed, sea level was almost stable. But as climate change warms the oceans and melts glaciers, sea level is rising by three millimeters a year. In February a United Nations panel on climate change predicted that seas would be more than a foot (0.3 meters) higher by 2100. And one of the nation’s top climate scientists thinks that forecast is far too modest. James Hansen, director of the NASA Goddard Institute for Space Studies in New York City, notes new data from satellites showing accelerated melting of the vast ice sheets in Greenland and West Antarctica. “If we go down the business-as-usual path,” he says, “we will get sea level rise measured in meters this century.”

The impact on New Orleans? A meter of sea level rise would be enough to turn New Orleans into the new Big Easy Reef—or a new Amsterdam, behind massive dikes. That’s assuming that big hurricanes don’t come more often; chances are they will. Hurricane frequency in the Atlantic waxes and wanes over a decades-long cycle that is now on the upswing. For this year, hurricane forecasters are predicting seven to ten hurricanes in the Atlantic Basin, with up to five reaching Category 3 or above—more than double the average from 1950 to 2000. The Gulf Coast faces 50-50 odds of being hit by a Katrina-size storm this summer. Already, tropical storms in the Atlantic are 50 percent more common than at the previous peak, in the 1950s, say Peter Webster and Judith Curry of the Georgia Institute of Technology. The frequency of truly monster storms—Categories 4 and 5—has doubled since 1970.

These trends have persuaded some researchers that the natural cycle is not the only factor driving up hurricane activity. Global warming is boosting sea-surface temperatures in hurricane alley—the tropical Atlantic and Caribbean—and warm seas are rocket fuel for stronger hurricanes. Before Katrina made landfall, it had exploded from a Category 3 storm to a Category 5 in 12 hours, partly because it stirred up a deep pocket of warm water in the Gulf. Only when it reached the Louisiana coast did the storm weaken again to a Category 3, sparing New Orleans an even greater catastrophe. If global warming produces stronger storms on top of the decadal cycle, 2005, with Katrina, Rita, and two other mega-hurricanes in the Atlantic, could be a stormy precursor of the coming century.

“The future of New Orleans looks bleak,” says Ivor van Heerden, deputy director of LSU’s Hurricane Center, who led the state’s investigation of the Katrina disaster. “We have to recognize that global warming is part of our future, sea level rise is part of our future, more storms are part of our future. You flood those houses one more time, nobody is going to come back. And the rest of the country will lose interest.”

For the moment, the city’s prospects have brightened a little. Some of the 110 billion dollars in federal reconstruction funds is starting to trickle into homeowners’ hands, and with the rebuilding plan issued in March the city finally has a blueprint for repairing its infrastructure and sparking a revival. The state has passed its first building code ever to help storm-proof future homes, while the fractious levee boards have merged into two state entities. The Corps of Engineers has 5.7 billion dollars to beef up the city’s hurricane defenses and is releasing a long-awaited, supercomputer-generated, flood risk analysis that will help it craft a new hurricane-protection and coastal-restoration plan. Congress even gave the state a slice of oil and gas royalties from a new swath of the deep Gulf recently opened to drilling—to be used to restore the rapidly eroding wetlands, coastline, and barrier islands, which might one day provide some protection from future storms.

Torbjörn Törnqvist, a Dutch coastal geologist now at Tulane, is a rare scientist who is bullish about the future, seeing New Orleans’ struggles with rising seas and stronger storms as a preview of what other coastal cities will soon face. He envisions a new urban landscape perfectly adapted to climate change, with restored wetlands, high-tech floodgates similar to those in the Netherlands, and a cleaner, greener, denser city. The entire pre-Katrina population, he contends, could live quite comfortably in the parts of the city that did not flood, transforming warehouses and blighted districts into new walkable, sustainable neighborhoods on the high ground.

“The situation here is a huge opportunity for the city and the nation,” says Törnqvist, who says he can’t imagine Holland turning its back on Amsterdam, or Italy giving up on Venice. “If we walk away, we’ll miss a fantastic opportunity to learn things that will be useful in Miami, or Boston, or New York in 50 years.” That kind of revival, however, would require a massive infusion of federal help, better engineering than ever before, and more social and urban planning than regulation-loathing Louisianans have ever stomached.

But even if wind and water give the Big Easy a respite until the corps can guarantee legitimate 1-in-100-year hurricane protection, powerful social and demographic forces unleashed by Katrina may already be undermining the city’s revival. Researchers have found that major disasters tend to accelerate existing social and economic trends. A booming San Francisco rebuilt bigger and better after its 1906 earthquake and fire; while the decaying industrial city of Tangshan, China, needed a huge infusion of aid from the government to recover after a giant earthquake in 1976—and was ultimately saved by the country’s burgeoning economy. It’s a sobering precedent for New Orleans, which has been plagued for decades by economic decline—just a single Fortune 500 company is still headquartered there—shrinking population, failing schools, and high crime.

“So why protect it? Why protect a piece of history that’s a cross between Williamsburg and Sodom and Gomorrah?” Oliver Houck sat in his office, hands locked behind his head, pondering the question on everyone’s mind. “There are people who will fight to the death to stay here because it’s such a damned joy to live here.”

But at what price? Houck paused for a moment to gaze out his window at the oak-strewn Tulane campus. The university lost two departments and a quarter of its students to Katrina, while he and his family spent months in exile after the storm. “If two words characterize all of southern Louisiana now, they would be ‘total uncertainty,’” Houck says. “It’s the total talk around the table. It’s the conversation you’re having with friends and spouses, even strangers. What do we do now?”

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