Cadillac Desert_ The American West and Its Disappearing Water - Marc Reisner [169]
There was an exquisite irony in this. Most of the Indians of the Southwest were hunter-gathers when whites arrived; a purely agricultural culture such as the Hohokam no longer existed. When the whites came and killed off the buffalo and antelope and ran the Indians onto reservations, their old way of life perished, and they had no choice but to become farmers or wards of the state. The reservation land they got, however, was, for the most part, land no one else had wanted. Much of it was terrible farmland, too sandy or infertile or high in elevation to grow anything well. Because it was such poor land, it required a lot of irrigation water, and the government had implicitly attached large water rights to it—rights that were confirmed in 1908 by the Supreme Court under the Winters doctrine. The Navajo Reservation in Arizona carried implicit rights to nearly 600,000 acre-feet, about one-fifth of the natural runoff of the state. Now, according to the Supreme Court, the Navajo could use every drop of that water during an extended drought even as people in Phoenix and Tucson were being allocated five gallons per day, even as millions were fleeing Los Angeles and leaving it the largest ghost town in the world. It probably wouldn’t come to that, but the Indians, where water was concerned, clearly had the upper hand. The white man’s cavalry had made beggars of them; now his courts had made them kings.
Things looked pretty bleak for southern California after the Supreme Court decision. At some point it would presumably have to give up the 600,000 acre-feet of Arizona’s entitlement it was diverting, enough water for the city of Chicago. But things looked bleak for Arizona, too, because the Central Arizona Project, which was supposed to deliver the water to Phoenix and Tucson and the dying farmland in between, was neither built nor even authorized, and California could be counted on to try to achieve politically what it hadn’t been able to achieve in court. Only the Indians were satisfied with what they had won. As it would turn out, however, things were even worse for California and Arizona—white man’s Arizona—than they looked.
The 17.5-million-acre-foot yield that the Compact negotiators had ascribed to the Colorado River was based on about eighteen years of streamflow measurement with instruments that, by today’s standards, were rather imprecise. During all of that period, the river had gone on a binge, sending down average or above-average flows three out of every four years. Not once had the flow dropped below ten million acre-feet, as it had repeatedly during the Great Drought of the 1930s. But all it takes to make statisticians look foolish is a few very wet or very dry years. In San Francisco, precipitation records have been kept for more than a hundred years—a log which, one might think, is good enough for a highly accurate guess. But 1976 and 1977, two unprecedented drought years, lowered the average rainfall figure from 20.66 to 19.33 inches. In a marginal farming region such as the Great Plains, an inch less precipitation can mean all kinds of trouble. In a desert region such as the Southwest, utterly dependent on one river, a difference of a couple of million acre-feet can spell disaster.
The first serious doubts about the 17.5-million-acre-foot figure were raised by Raymond Hill, a distinguished hydrologic engineer, at a conference in Washington, D.C., in 1953. “The discharge of the Colorado River at Lee Ferry [near the Arizona-Utah border],” Hill told his disbelieving audience, “has averaged only 11.7 million acre-feet since 1930.” As Hill pointedly noted, the Colorado Basin states had not only been counting on 17.5 million acre-feet per year; they had been building and planning as if they thought that figure was conservative. But during the