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"Rain" to the Rescue. The "rain" will come none too soon; the project is a rescue job. Californians have long been cultivating more land than their local rivers can irrigate. In years of low water yield, hundreds of thousands of acres revert to desert.
Next month a full-dress celebration will greet the Sacramento water as it marches south, but desperate farmers are already using the trickles raised to test the pumps. Next year many of them will see the end of their water troubles. The bureau figures that the Sacramento water will bring 500,000 desert acres under cultivation and give crop-saving supplemental water to 500,000 acres more.
Water Export. Such water exchanges will be used in many future projects, but the bureau believes that an even more radical trick, "water export," will have to be used before the rivers of the West can do their full duty.
Rivers, the experts say, fall into two classes: 1) those with more water than can be used profitably in their own basins, and 2) those with more irrigable land than the river can water. Obviously, water should be exported from basins with a water surplus.
One big project, now partly in operation, already exports water from one basin to another. Within the state of Colorado, the Colorado River is a "surplus" stream. The parched states lower down the river could use more of its flow, but by interstate agreement Colorado is entitled to more water than it can use in its share of the Colorado watershed. So the Bureau of Reclamation has built a complex system of dams, reservoirs, pumps and tunnels to lead part of the upper Colorado through the Rockies and spill it down the eastern slope near Denver.
Through the Tunnel. Granby Dam catches some 450,000 acre-feet of the Colorado's water. A pumping station (18,000 h.p.) lifts it 181 feet and pushes it under the snow-capped Continental Divide, 12,000 feet high, through a tunnel 13 miles long. When the water finally reaches the edge of the dry Great Plains, it gives supplemental irrigation to 600,000 acres of scantily watered land. Water export of this sort, the bureau believes, can be used in many parts of the West to make water-rich basins help water-poor ones.
Some years ago the bureau's top strategists began to study the western half of the U.S. as a hydrographic whole. What they saw was not novel, but as viewed in their recently raised sights it took on new importance. A project that had been a dream is now a real possibility: to bring the water of Oregon into the dry Southwest.
Across the Pacific Coast at the latitude of San Francisco runs a natural boundary (see map) that does not show on any ordinary map. Northwest of it, the country gets more water than it needs and the coastal mountains are clothed with dripping evergreens. Short, steep rivers gush like fire hoses. South of the boundary, the country changes abruptly. The forests dwindle and thin out; the rivers are poor, weak things that usually go dry in summer.