The Efficiency Paradox

Why water conservation along the Colorado River — a much-vaunted silver bullet for the West’s coming era of shortage — could have devastating environmental costs

  • An endangered Yuma clapper rail in Colorado River Delta wetlands

  • A 23-mile-long earthen section of the All-American Canal will be lined to save 67,700 acre-feet of water a year for the Imperial Irrigation District — water that for more than 70 years has seeped into the Mexicali Valley

  • Mexicali Valley farmers like Luis Hernández, left, brother of Gerónimo, use well water fed by seepage from the All-American Canal to irrigate crops

  • Children in a Mexicali Valley canal, center

  • Flooding in the Mexicali Valley in the 1950s caused by seepage from the newly constructed All-American Canal, right. Drainage canals were later built to capture the water for irrigation


  • The Colorado River runs dry at the border


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In the early 1980s, however, El Niño provided a brief, brilliant reminder of just what it is that natural “inefficiencies” do — most spectacularly in 1983, when storms stuffed so much snow and rain into the Rockies that the U.S. government was forced to crank wide the spill gates on Glen Canyon Dam as torrents of water charged toward the sea. The downriver surge created a massive, defibrillating spike on the hydrograph that burst Mexican levees and inundated much of the Delta. Like a patient swimming up out of a coma, the Delta showed signs of renewed life.

In 1999, Environmental Defense and several other conservation groups took up the Colorado River Delta’s cause. They suggested that a reliable source of water for a “base flow,” backed up with the occasional flood, could probably keep alive the 150,000 acres of wetlands that had come back. With the reservoirs upstream brimming with water, holding the line in the Delta did not seem like a preposterous proposition: It would take just two-tenths of 1 percent of the river’s long-term annual average flow, boosted by a flood pulse every four years of 1.8 percent of the river’s flow.

Almost as soon as the proposal hit the streets, the current drought descended on the Colorado River, and the surplus water evaporated.

The Delta cannot conceivably be restored unless the seven Colorado River states in the U.S., which control 91 percent of the water in the river, lift a finger to help. There is a clear ecological link between the United States and the Delta: The river in Mexico provides crucial habitat both for birds that are federally protected as endangered in the U.S., and for migratory birds that wing their way up the Pacific Flyway into what the farmers along the border refer to as Gringolandia.

The states and the U.S. federal government have, however, consistently refused to include the Delta in the equation by which they run the river. They have, in the language of economists, largely externalized the environmental costs of water development from their calculations. In 2005, for example, California, Nevada and Arizona signed what they hailed as a landmark Multi-Species Conservation Program for the Lower Colorado River, designed to protect endangered species while allowing those states to continue siphoning water out of the river. The Delta is conspicuously absent from the plan.

Now, the drought on the Colorado is dragging into what could be its eighth year. The seven states are urgently finalizing a plan to prepare for the catastrophic shortages that will come with a prolonged megadrought of the sort that climate researchers have found evidence of in the not-so-distant past. From synching up the operation of Hoover and Glen Canyon Dams to meet water demands more efficiently, to building a new “Drop 2” reservoir in the Imperial Valley to catch inadvertent “overdeliveries” and flash floods that otherwise would escape down the river to Mexico, the states are turning their collective weight toward ironing out every last inefficiency on the river with an enthusiasm unseen since the original dam-building campaign.

It is hard to believe that there’s much left to iron out. Today, about 20 miles below Morelos Dam, where Mexico siphons the majority of its share of Colorado River water to the Mexicali Valley, the river is literally as dry as dust. And yet, further downstream, in a no-man’s land of marginal farms that the Mexican government ordered depopulated in 1976 and is slowly being reclaimed by the desert, the river, amazingly, re-emerges.

The vast majority of the Mexicali Valley drains to the Colorado River, and, somewhere out on the west edge of the valley, reed-lined drainage canals gather the water that has run off the area’s farm fields. Like some mystical essence of the universe revealing itself, this is Julio Navarro’s pérdidas de agua — water that has leaked from the valley’s irrigation network, but has not been truly lost. The drains merge to form the Rio Hardy, a short tributary that returns water to the very bottom of the Colorado River watershed and the Delta. Much more drainage water remains unseen, in the form of groundwater that lies just below the surface, where plants can tap it with their roots.

By the standard calculations of the Colorado River’s water users, the wastewater that makes its way back here is the merest trickle of the river’s total flow. But it can be quantified in another extremely important way: It is enough to sustain life. Today, even though they are choked with tamarisk, the Delta’s lagoons are secret worlds full of herons, pelicans and cranes. The place feels like the world after humans are done with it, the world left over. It is filled with the birds, and the sound of the wind, and crowned by an infinite expanse of sky.

Few people know the Delta better than Francisco Zamora, who works for the Tucson, Ariz.-based Sonoran Institute and manages its Delta restoration program. Zamora has a habit of making himself look small under his ball cap, but his mind is constantly at work puzzling out the enigmas of the Delta. His group is now partway into a pilot restoration project on the river, an effort largely focused on re-establishing cottonwood, willows and mesquite in areas overtaken by tamarisk. But the main need now, says Zamora, is water.

The behavior of the entire hydrologic cycle in the Delta — how water is taken out of the Colorado at Morelos Dam, how it flows through the irrigation district, and the ways in which it returns to the Delta — is poorly understood. As a nonprofit, Zamora says, “We haven’t been able to get all the resources we need” to tackle those questions. But he is working on it.