Just outside the dusty Mexican town of Carranza, Francisco Zamora wheels his Toyota pickup off the highway and down a gravel road along an irrigation canal. To one side, irregular farm fields flash by, fringed with reeds, sunflowers and an occasional shaggy palm. On the other side lies the bone-dry bed of the Colorado River. Straitjacketed between two levees roughly a mile apart and choked with mean, gray-green tamarisk, or salt cedar, it nonetheless has an emphatic presence – like a prehistoric creature waiting to rumble back to life.
It's hard to imagine that, a century ago, wetlands and impenetrable cottonwood, willow and mesquite forests covered nearly 2 million acres here. After Aldo Leopold visited in 1922, he rhapsodized about the Delta's "hundred green lagoons," where the river twisted and split and braided together again before finally disappearing into the Gulf of California. Huge freshwater flows, powerful saltwater tides barreling up from the Gulf, and millions of tons of rich sediment converged to make the Delta an unlikely Eden on the edge of the Sonoran Desert. Home to more than 350 species of birds, it was a key part of the Pacific Flyway, a wild, immense and occasionally magical dreamscape prowled by jaguars and exploding with waterfowl.
But a series of big dams upstream gradually strangled the Delta. First came Hoover, in 1937. Just seven years later, Godfrey Sykes, an explorer and engineer who followed in Leopold's footsteps, likened the now-harnessed river to "a bird in a cage, or an animal in a zoo." In 1950, Mexico's Morelos Dam went into operation. And finally, in 1963, Glen Canyon Dam began impounding any leftover water to create Lake Powell.
Those formidable waterworks, along with the many smaller dams and diversions built throughout the Colorado's 224,000-square-mile drainage area, have transformed the river into a gigantic water-supply system for Wyoming, Colorado, Utah, New Mexico, Arizona, Nevada and California, and the Mexican states of Sonora and Baja California. The Delta, meanwhile, has shrunk to less than one-tenth of its original size; over the past 50 years, the river has only occasionally reached the sea. And the stranglehold has tightened over the past 14 years, as the river suffers through its worst drought in more than a century.