Cadillac Desert (83 page)

The survival of a civilization depends mainly on sufficient food. But what makes a civilization great? Traveling across the United States, Lewis and Clark saw few fat Indians until they had arrived at the mouth of the Columbia River, where the Chinook were gorging themselves on salmon, oysters, and clams. With plenty of time for leisure, the Northwest Indians were making exquisite crafts and living in impressive lodges. Farther north, the Haida, similarly well fed, had ample time and energy to commit cruel depredations on fellow tribes in magnificent war canoes carved from whole trees. When we think of a great civilization, however, we think of great cities, of sublime architecture and monuments, of intricate governmental and social structures, of engineering ability which startles even the jaded modern observer. By that standard, neither the Chinook nor any of the other cultures in North America—except the Hohokam—was great. Individually, the Indians could be incredibly skillful—as horsemen, warriors, hunters, artisans—but their high achievement was just that: individual. Even where Indians shared a common language, they broke up into small, separate tribes that, for the most part, went their own way. In contrast to the collectivism of the great Mediterranean, Indus Valley, or Mayan city-states, North American Indian culture was fragmented, atomized, ephemeral.

Most of the great Mediterranean civilizations arose in a region notable for its benign weather. But the climate in California is very similar to that of southern Italy and Greece, and California was a gastronomical paradise on earth, with salmon in the rivers, acorns for the taking, whales grounding themselves on beaches, and enormous herds and flocks of game. But the Hurok and Miwok and Paiute tribes were living in caves and under trees when the Greeks and Romans were building aqueducts and the Parthenon.

An answer to this riddle begins to emerge when one considers that nearly all the great early civilizations were irrigated ones. That single act—irrigation—seems inextricably linked to their ascendance, as well as to their demise. Any people who, for the first time, managed to divert a river and seduce a crop out of wasted land had tweaked the majestic indifference of the universe. To bring off the feat demanded tremendous collective will: discipline, planning, a sense of shared goals. To sustain it required order, which led to the creation of powerful priesthoods, of bureaucracies. Irrigation invited large concentrations of people because of all the food; it probably demanded such concentrations because of all the work. Out of this, cities grew. Work became specialized. There had to be engineers, builders, architects, farmers—probably even lawyers, for the disputes over water rights among upstream and downstream irrigators could not have been much different from today’s. The ample supply of food may have helped in the keeping of slaves; in California, during the mission days, some of the Indians signed themselves into absolute servitude with the padres in exchange for the certitude of being fed.

Once established, irrigated civilizations in the desert were incredibly well off. Before modern weapons, sheer numbers meant power, so they were formidable in war. Oases in hostile deserts, they would have been difficult to approach and attack. The desert was also a healthy place to live. There was no tsetse fly, no malarial swamp, no raging cold and chilling wind. Because everyone was out of doors much of the time, the spread of disease was much less of a risk than in colder climates. Famine was an almost forgotten nemesis. Food was also a wonderful commodity for trade. Mesopotamia had virtually no metals, but it produced enough food to trade not only for iron and bronze but for a phenomenal wealth of gold. Trade was also a way of exchanging ideas; it was through contact with the Assyrians and Greeks that the Romans learned to build aqueducts.

There were, of course, problems. Canals could silt up or wash out in floods. A rigid bureaucratic order could spawn revolution. Any disruption of the water supply—by an earthquake, a drought—would be catastrophic. But those were not the kinds of problems likely to crush civilizations as ingenious as these. They might take their toll, along with wars and plagues, but it seems unlikely they would have sent them into permanent eclipse or, as in the case of the Hohokam, cause a whole civilization simply to vanish off the face of the earth. There had to be another enemy—something subtle, unseen, subversive. It was likely to be something they could do little or nothing about, something which they may not even have understood, and thus might have been inclined to ascribe to vengeance from gods. Contemplating the list of enemies, natural and man-made, that might fit such a description, more and more anthropologists and archaeologists are concluding that the one that fits it best is salt.

Irrigation is a profoundly unnatural act. It hardly occurs in nature, and that which does occur is mostly along the rare desert rivers, like the Nile, that produce a reliable seasonal flood. In Africa and a few other places, there are natural depressions where runoff collects during rainy seasons, greening the land when it recedes. For every one of those, however, there are dozens of dead saline lakes or lake beds where the same thing used to happen and where, today, nothing can grow. They are common in Nevada—Groom Lake, Newark Lake, Goshute Lake, Winnemucca Lake, China Lake, Searles Lake, Cuddleback Lake—big saucers of salt left over from shallow Pleistocene seas, when the climate of Nevada was more like Szechuan. The waters that filled those lakes came down from ranges a short distance away, but in that brief intimacy with soil and rock had already accumulated enough salts to spell death for the basin below.

Man-made irrigation faces the same problem. In the West, many soils are classified as saline or alkaline. Irrigation water percolates through them, then returns to the river. It is diverted downstream, used again, and returned to the river. On rivers like the Colorado and the Platte, the same water may be used eighteen times over. It also spends a good deal of its time in reservoirs which, in desert country, may lose eight to twelve feet off their surface to the sun every year. The process continues—salts are picked up, fresh water evaporates, more salts are picked up, more fresh water evaporates. The hydrologist Arthur Pillsbury, writing in
Scientific American
in July of 1981, estimated that of the 120 million acre-feet of water applied to irrigated American crops the previous year, ninety million acre-feet were lost to evaporation and transpiration by plants. The remaining thirty million acre-feet contained virtually all of the salts.

Above a heavily irrigated strip of land along the Pecos River in New Mexico, water taken from the river has a measured salinity level of about 720 parts per million. Thirty miles beyond, salinity levels have shot up to 2,020 parts per million, almost entirely because of irrigation; 2,020 parts per million spells death for many crops. Near its headwaters in the Colorado Rockies, the Arkansas River shows only a trace of salts. A hundred and twenty miles downriver, it contains 2,200 parts per million. The Colorado, a river whose importance is absurdly disproportionate to its size, has the worst problem with salt of any American river. There are small tributaries flowing out of the salt-ridden Piceance Basin with measured concentrations of as much as ninety thousand parts per million—three tablespoons in a cup—so it is plagued by natural sources to begin with. In the Grand Valley of Colorado, irrigation water runs through sedimentary salt formations on its subterranean return to the river, reaching saline levels thirty times higher than at the diversion point. Below there are two huge reservoirs, Powell and Mead, evaporating a million and a half acre-feet of pure water each year—at least a tenth of the river’s flow. It should come as no surprise, then, that by the time the Colorado River has entered Mexico, its waters are almost illegal.

Behind Jan van Schilfgaarde’s desk in his office at the Department of Agriculture’s Salinity Control Laboratory, in 1982, is a plaque proclaiming him a member of the Drainage Hall of Fame. Drainage seems like a pedestrian business, and van Schilfgaarde is an uncommonly sophisticated and witty man, so one wonders what odd fortune married him to this issue. As he explains it, however, drainage becomes the most difficult aspect of irrigation—rather like fine-tuning a racing car. In fact, on the face of things, drainage would appear a more challenging problem than building dams. On the Columbia River, Grand Coulee Dam is in place, impassive and content. Next door, in the Columbia Basin Project, the battle against poor drainage and salts is still going on.

“When you apply irrigation water,” says van Schilfgaarde, “it has to go somewhere. If it drains back off into the river, quickly, then that’s fine. If it drains down to an underlying aquifer, fine—at least for a while. If it doesn’t drain or drains too slowly, then you have problems. Salts build up in the root zones. The soil becomes waterlogged. Ultimately you can damage the structure of the soil, ruining it forever. So you have to get rid of it. How? Where? These are tremendous problems in places with lots of poorly drained land that apply tens of millions of acre-feet of water per year, like the American West. Basically, you can take the macro or the micro approach. You can build big drain systems, desalination plants, and so on, but you are still left with saline wastewater or pure salt to dispose of. Or you can tune your crop mix and your irrigation system to the reality of poor drainage and saline water and keep the problem at bay. That is what we have been doing here, with considerable success. I keep telling people this but they don’t want to listen to me.”

“Here” is the Department of Agriculture’s Salinity Control Laboratory, of which van Schilfgaarde was then director. It sits in the shadow of a hulking butte near the city of Riverside, California, surrounded by the very last agricultural land in the Los Angeles Basin. Sixty years ago, this was, acre for acre, the richest farming region in the world. Los Angeles County led the nation in farm income. Today, the main crop in the basin is tract housing. Displaced by twelve million people, agriculture moved eastward and northward into the San Joaquin Valley, which has one of the worst drainage problems in the world.

“Salinity is the monkey on irrigation’s back,” says van Schilfgaarde. “The good water goes up in the sky and the junk water goes down, so the problem gets worse and worse. Victor Kovda of the University of Moscow says the amount of land going out of production due to salinity now surpasses the amount being brought into production through new irrigation. In this country, we have lost a few tens of thousands of acres—actually a few hundreds of thousands if you include the Wellton-Mohawk Project in Arizona, on which we later spent a fortune in order to bring salted-out land back into production. But that figure is projected to increase drastically in the decades ahead. The problem is an abstraction to most people, like projections of declining oil reserves were back in the 1960s. If you want to see how bad it can get, go to Iraq.”

Thousands of years before the birth of Christ, the Sumerians in the Fertile Crescent were already getting some experience with salinity firsthand. Counts of grain impressions in excavated pottery from sites in what is now southern Iraq—pottery that has been carbon-dated back to 3500 B.C.—suggest that at the time, the amount of wheat grown was roughly equal to the amount of barley. A thousand years later, wheat production had dropped by 83 percent. It wasn’t that the Sumerians suddenly developed an insatiable craving for barley; they were forced to switch because wheat is one of the least salt-tolerant crops. Between 2400 B.C. and 1700 B.C., barley yields in Sumeria declined from twenty-five hundred per hectare (a highly respectable yield even today) to nine hundred liters per hectare. Not long afterward, massive crop failures began. “Sodium ions tend to be absorbed by colloidal clay particles, deflocculating them,” reads an article in
Science
magazine from 1958—the first authoritative report linking the demise of Sumeria to salt. “[This] leaves ... the resultant structureless soil almost impermeable to water. In general, high salt concentrations obstruct germination and impede the absorption of water and nutrients by plants. Salts accumulate steadily in the water table, which has only very limited lateral movement to carry them away. Hence the groundwater everywhere [in southern Iraq] has become extremely saline.... New waters added as excessive irrigation, rains, or floods can raise the level of the water table very considerably under the prevailing conditions of inadequate drainage. With a further capillary rise when the soil is wet, the dissolved salts and exchangeable sodium are brought into the root zone or even to the surface,” killing the crops. As the authors—Thorkild Jacobsen and Robert Adams—suggested, Iraq is still struggling with its most ancient nemesis. It can feed itself mainly because it exports oil. At least 20 percent of its arable land (which doesn’t amount to much) is permanently destroyed and can never be returned to cultivation. “Probably there is no single explanation,” the authors wrote, “but that growing soil salinity played an important part in the breakup of Sumerian civilization seems beyond question.”

Van Schilfgaarde’s approach to the salinity problem is not the one favored by the farmers, the Bureau of Reclamation, and members of Congress in whose districts the problem lies. “The Bureau says we’ve analyzed the solutions I am talking about and they’ve been discredited, which is utter nonsense. Nobody has had the guts to implement them. I’m an outcast at every meeting I go to.” The solutions favored by van Schilfgaarde belong to a kind of jujitsu style; the prevailing wisdom is to attack the problem with tanks and planes. “I have been saying for years that the solution to this problem is better management—very careful management,” he says, his urbane Dutch manner giving way to rising exasperation. “Certain crops can take high salinity levels. At our experimental plots in the San Joaquin Valley, we have been growing cotton for six years with fifty-nine hundred parts per million water
and
getting 50-percent-higher yields. The salt stress seems to stunt the plants but doesn’t affect their production of cotton flowers. The water also has boron in it—an average irrigator wouldn’t touch it. This shows that you can use water on one crop, then on one that tolerates salt better, then bring it back and use it again on a still more salt-tolerant crop before letting it go. You use a lot less, which means that you have less to get rid of in poorly drained areas such as the San Joaquin Valley. The cost is low—about $10 an acre. The cost of the Yuma Desalination Plant is
officially
up to $300 million.”