Sunday, Sep 7, 2008
Long before Hurricane Katrina, New Orleans was in a precarious state -- caught in an ongoing war with the mighty Mississippi River.
Aug 30, 2005 | For those watching the near-cataclysmic results of Hurricane Katrina, and wondering how New Orleans ever fell into such a precariously vulnerable position, John McPhee's great 1989 book "The Control of Nature" offers concrete answers. Each of the three parts of the book deals with a different region where man has been at war with nature: in Los Angeles, Iceland and, most important at this moment, the lower Mississippi River. Katrina is, of course, a case of nature waging war on man. But its damage and devastation may be felt all the more in places like New Orleans, where sturdy and deeply rooted men and women have faced off with the great river we call the Mississippi again and again. In this excerpt from "Atchafalaya," the first chapter from "The Control of Nature," McPhee draws affectionate portraits of the men of the Army Corps of Engineers and others who toil on behalf of "progress." Yet, it's clear which side he comes down on in these fights. His work reminds us that there are things more powerful than we are, and that nature, however hard we try to control it, will run its course.
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Something like half of New Orleans is now below sea level -- as much as fifteen feet. New Orleans, surrounded by levees, is emplaced between Lake Pontchartrain and the Mississippi like a broad shallow bowl. Nowhere is New Orleans higher than the river's natural bank. Underprivileged people live in the lower elevations, and always have. The rich -- by the river -- occupy the highest ground. In New Orleans, income and elevation can be correlated on a literally sliding scale: the Garden District on the highest level, Stanley Kowalski in the swamp. The Garden District and its environs are locally known as uptown.
Torrential rains fall on New Orleans -- enough to cause flash floods inside the municipal walls. The water has nowhere to go. Left on its own, it would form a lake, rising inexorably from one level of the economy to the next. So it has to be pumped out. Every drop of rain that falls on New Orleans evaporates or is pumped out. Its removal lowers the water table and accelerates the city's subsidence. Where marshes have been drained to create tracts for new housing, ground will shrink, too. People buy landfill to keep up with the Joneses. In the words of Bob Fairless, of the New Orleans District engineers, "It's almost an annual spring ritual to get a load of dirt and fill in the low spots on your lawn." A child jumping up and down on such a lawn can cause the earth to move under another child, on the far side of the lawn.
Many houses are built on slabs that firmly rest on pilings. As the turf around a house gradually subsides, the slab seems to rise. Where the driveway was once flush with the foor of the carport, a bump appears. The front walk sags like a hammock. The sidewalk sags. The bump up to the carport, growing, becomes high enough to knock the front wheels out of alignment. Sakrete appears, like putty beside a windowpane, to ease the bump. The property sinks another foot. The house stays where it is, on its slab and pilings. A ramp is built to get the car into the carport. The ramp rises three feet. But the yard, before long, has subsided four. The carport becomes a porch, with hanging plants and steep wooden steps. A carport that is not firmly anchored may dangle from the side of a house like a third of a drop-leaf table. Under the house, daylight appears. You can see under the slab and out the other side. More landfill or more concrete is packed around the edges to hide the ugly scene. A gas main, broken by the settling earth, leaks below the slab. The sealed cavity fills with gas. The house blows sky high.
"The people cannot have wells, and so they take rainwater," Mark Twain observed in the eighteen-eighties. "Neither can they conveniently have cellars or graves, the town being built upon 'made' ground; so they do without both, and few of the living complain, and none of the others." The others may not complain, but they sometimes leave. New Orleans is not a place for interment. In all its major cemeteries, the clients lie aboveground. In the intramural flash floods, coffins go out of their crypts and take off down the street.
The water in New Orleans' natural aquifer is modest in amount and even less appealing than the water in the river. The city consumes the effluent of nearly half of America, and, more immediately, of the American Ruhr. None of these matters withstanding, in 1984 New Orleans took first place in the annual Drinking Water Taste Test Challenge of the American Water Works Association.
The river goes through New Orleans like an elevated highway. Jackson Square, in the French Quarter, is on high ground with respect to the rest of New Orleans, but even from the benches of Jackson Square one looks up across the levee at the hulls of passing ships. Their keels are higher than the Astro Turf in the Superdome, and if somehow the ships could turn and move at river level into the city and into the stadium they would hover above the playing field like blimps.
In the early nineteen-eighties, the U.S. Army Corps of Engineers built a new large district headquarters in New Orleans. It is a tetragon, several stories high, with expanses of sheet glass, and it is right beside the river. Its foundation was dug in the mainline levee. That, to a fare-thee-well, is putting your money where your mouth is.
Among the five hundred miles of levee deficiencies now calling for attention along the Mississippi River, the most serious happen to be in New Orleans. Among other factors, the freeboard -- the amount of levee that reaches above flood levels -- has to be higher in New Orleans to combat the waves of ships. Elsewhere, the deficiencies are averaging between one and two feet with respect to the computed high-water flow line, which goes on rising as runoffs continue to speed up and waters are increasingly confined. Not only is the water higher. The levees tend to sink as well. They press down on the mucks beneath them and squirt materials out to the sides. Their crowns have to be built up. "You put five feet on and three feet sink," a Corps engineer remarked to me one day. This is especially true of the levees that frame the Atchafalaya swamp, so the Corps has given up trying to fight the subsidence there with earth movers alone, and has built concrete floodwalls along the tops of the levees, causing the largest river swamp in North America to appear to be the world's largest prison. It keeps in not only water, of course, but silt. Gradually, the swamp elevations are building up. The people of Acadiana say that the swamp would be the safest place in which to seek refuge in a major flood, because the swamp is higher than the land outside the levees.
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