In retrospect, the idea was so stupid and yet so American: Move the homeless, the elderly, the impoverished, the unlucky, all those poor souls who couldn't get out of New Orleans in time to avoid Hurricane Katrina; move them into the city's cavernous domed football stadium. Anyone who has seen a disaster movie could have predicted what would happen next: Katrina slammed into the Superdome, ripped off the roof, and knocked out the power, cutting off the drinking water and the air conditioning. Those trapped inside had to be moved again—to Houston's Astrodome, of course.
If it's not too callous to say so while the tragedy on the Gulf Coast is still unfolding, the stadium mishap is an apt metaphor for New Orleans' environmental history. The sodden city has long placed itself in harm's way, relying on uncertain artifice to protect it from unpredictable environs.
New Orleans is utterly dependent for its survival on engineered landscapes and the willful suspension of disbelief that technology has allowed its citizens to sustain. As most people know by now, much of New Orleans lies well below sea level and also beneath the Mississippi River, which flows high above the city it helped create. If you visit New Orleans you can't actually see the river unless you're willing to climb its steep banks, mini-mountains that jut above the Mississippi's endlessly flat delta. From the relatively high ground of the French Quarter, you might catch a glimpse of a huge container ship, seemingly levitating above the roofline of most houses. New Orleans is, in other words, a shallow bowl surrounded by a ridge of levees, which are supposed to keep out water from the Mississippi and from Lake Pontchartrain at the city's rear—and this week didn't. When the levees fail, as they have many times before, a flood occupies the recessed terrain in the city's center. Like the people trapped in the football stadium, water has no natural way to leave New Orleans. It must constantly be pumped over the lip of the bowl formed by the levees.
New Orleans' dysfunctional relationship with its environment may make it the nation's most improbable metropolis. It is flood prone. It is cursed with a fertile disease environment. It is located along a well-worn pathway that tropical storms travel from the Atlantic to the nation's interior. From this perspective, New Orleans has earned all the scorn being heaped upon it—the city is a misguided urban project, a fool's errand, a disaster waiting to happen.
But such insults miss why most American cities are built in the first place: to do business. In 1718, when the French first settled New Orleans, the city's earliest European inhabitants saw riches inscribed by the hand of God into the landscape of the vast Mississippi valley. The Mississippi river system takes the shape of a huge funnel, covering nearly two-thirds of the United States from the Alleghenies to the Rockies. The funnel's spout lies at the river's outlet at the Gulf of Mexico, less than 100 miles downstream from New Orleans. In an era before railways, good highways, and long before air travel, much of the interior of the nation's commerce flowed along the Mississippi, fronting New Orleans. The river system's inexorable downstream current swept cotton, grain, sugar, and an array of other commodities to New Orleans' door. Because of the region's geography and topography, many 19th-century observers believed that God—working through nature, His favorite medium—would see to it that anyone shrewd enough to build and live in New Orleans would be made rich.
So, people built. Some lived. A lucky few even got rich. Many others, usually poor residents, died. They were carried away in floods. They were battered by catastrophic storms. They were snuffed out by yellow fever epidemics, like the great scourge of 1853 that killed nearly 10,000 people in the city. Over time, New Orleans developed a divided relationship with the environment: Nature, as embodied by the Mississippi, promised a bright future. But it also brought water, wind, and pathogens, elements of a fickle environment that in the past as now turned cruelly chaotic.
Geographers refer to this as the difference between a city's "situation"—the advantages its location offers relative to other cities—and its "site"—the actual real estate it occupies. New Orleans has a near-perfect situation and an almost unimaginably bad site. It's because of the former that people have worked endlessly to overcome the hazards of the latter.
From the first, New Orleans turned to technology to impose order on its environs. Since engineers began to figure out how to drain the city adequately in the mid-19th century, they have struggled mightily to do so. Over time they built a network of enormous pumps (several of which have failed in the face of Katrina) and hundreds of miles of canals—a quantity to make a Venetian feel at home. Their feats, however incomplete, have allowed the city to expand off the relatively high ground near the Mississippi and to spread out into what used to be a huge cypress swamp along the shore of Lake Pontchartrain.
New Orleans' early settlers also built artificial levees. At first they were little more than crude efforts to augment the natural riverbanks. But for more than two centuries, engineers steadily ramped up their project, and today the levees have grown so high that they loom over the city below. New Orleans has literally walled itself off from the Mississippi. This is all part of the effort to realize the promise of the city's situation while keeping at bay the forces that buffet its site. Of course, in its present condition, the city faces two truths: First, even today the levees are not impregnable. And second, the higher the defenses are built, the more difficult it becomes to remove water from New Orleans once it finds a way inside.
Most of the time, New Orleans can forget the perils of its environment. With the levees standing between the city and the Mississippi, it is possible to ignore the river peering down into town. And unless you happen upon one of the huge pumping stations that dot the city and manage to figure out what's inside the anonymous structure, there's no reason to consider the city's peculiar hydrology. But now, with water flowing 20 feet deep in some places, New Orleans is forced to remember that it is trapped in a cage of its own construction. Most of the city's residents will be saved, but its site cannot be airlifted to Texas.