The Colorado River drains seven states in the U.S. before it skirts the Mexicali Valley; in the Days Before Dams, it went on to empty into the Sea of Cortez. Yet for the seven U.S. states, the Mexicali Valley might as well be the dark side of the moon.

In its last 100 miles, the river provides water to some half-million acres of farmland — more land than is farmed in the Imperial Valley — and 3.1 million people, not only in the Mexicali Valley but also in places like Tijuana, which lies on the coast, just across the border from San Diego, and is the largest city in the Mexican state of Baja California. That water is the last of the river’s flow: the 9 percent that Mexico is entitled to under a 1944 treaty with the United States.

The city of Mexicali, the capital of Baja California, has a scruffy air, but it is undeniably booming — thanks in large part to the maquiladoras that have risen from the Sonoran Desert scrub to crank out products bound for the U.S. A local business group called the Mexicali Economic Development Council, led by some of the area’s leading entrepreneurs and commonly known by its Spanish abbreviation, CDEM, has shouldered the somewhat contradictory task of promoting economic growth and quality of life in the city. And it has spearheaded the fight against the All-American Canal lining project.

Last year, CDEM sued the United States in U.S. court, alleging that the federal government failed to adequately consider potential harm to animals on the U.S. endangered species list that depend on leakage-fed wetlands along the border. It also alleged that the canal lining would deprive people in the Mexicali Valley of water that they had come to depend on and acquired rights to, and would set off a wave of migration by displaced farmers. The federal appeals court in San Francisco has, for now, ordered the lining project stopped until it can untangle the case.

For René Acuña, CDEM’s executive director, the United States’ outright ignorance of the lining project’s impacts is yet one more chapter in the story of its blinkered attitude toward Mexico. “They said, ‘OK. South of the border is the end of the world,’ ” Acuña steams, before he comes back sounding like a copywriter for next year’s UNICEF cards. “We don’t see the fence that divides the countries. We see a region. We are interrelated. We share roots, families, air, water, everything.”

A hundred miles to the west, in the spit-shined dream that is San Diego, Dan Hentschke is not a person whose eyes turn misty at the notion of cross-border fraternity. Hentschke, who looks like a little Mr. Clean with Ben Franklin glasses, is the top lawyer for the San Diego County Water Authority. “Look. The Colorado River is fully appropriated. There is no other water to give around. It’s done,” he says. “Everybody knows what they have. And Mexico’s trying to get more than they have.”

Hentschke is fond of invoking the analogy of a leaky, 10-year-old garden hose and an unimaginably tactless neighbor. “When you turn on your faucet, the water leaks out, and trickles down into the ground, and waters your neighbor’s orange tree. So you go to Home Depot, and you buy a new hose. And the guy who owns the orange tree says, ‘Hey! You’ve had a leaky hose for years. Take a nail, and put a hole in that hose you just got, because I have a right to your water.’ ”


Even with the seepage from the United States’ leaky hose, Baja California is facing a looming water crunch. In downtown Mexicali, the local branch of the National Water Commis-sion is housed behind a whitewashed cinderblock wall that local children have painted with water-themed murals. There, a man named Julio Navarro oversees the valley’s massive irrigation district, and it feels as if he is barricaded inside his report-stuffed office. “Managing water,” he says, with a quietly exasperated laugh, “is managing conflict.”

A new study funded by the North American Development Bank occupies a prominent place on his desk and hints at the shape of the future. Almost all the water currently available for farms and cities in the Mexicali Valley is already being used. Farmers are also pumping out almost 25 percent more groundwater than is naturally recharged into the ground each year, running up a significant debt against the future. Cities — most prominently Mexicali, where a new wave of maquiladoras is buying up land on the outskirts, and Tijuana, on the coast — now use about 12 percent of the valley’s water, but they are expected to need twice as much by 2030.

The growing urban demand for water here is a mirror image of the water-strapped world north of the line, and the way out, Navarro says, is clear: tightening the system to recover the lost water. In fact, the Water Commission is already four decades into a water-efficiency improvement program — a program that, viewed one way, is essentially a perpetual effort to stay ahead of the coming conflict.

First, the government lined the main canals in the valley with concrete. Then it turned its attention to the secondary canals. Now, says Navarro, “we are working on the small ditches that deliver water directly to the fields” — and even on farmers’ fields themselves, footing half the cost of ominously named devices called laser levelers. These dust-billowing, laser-guided scrapers are hitched behind tractors and grade fields perfectly level, so water can be more evenly applied, increasing the amount available for consumption by crops — and reducing the amount lost to percolation and runoff.

Even after decades of efficiency efforts, however, the district still loses nearly 40 percent of the water in its system every year. Those losses materialize out of the pages of Navarro’s report and are tabulated as pérdidas de agua: a sort of gold worth chasing after and putting to productive use. And Baja California’s booming cities are now exploring an idea lifted straight out of San Diego’s book. “If the cities finance efficiency projects,” says Navarro, “they can get the saved water.” So far, he says, “they’re only talking about it. But we think maybe in a year, two years. …”


As overlooked as the Mexicali Valley is in the broader affairs of the Colorado River, there is a spot farther down the line that the dealmakers have ignored outright. It is the Colorado River Delta — a netherworld where, Before Dams, the river created nearly 2 million acres of lush wetlands as it flowed toward and into the Sea of Cortez. Surrounded by the Sonoran Desert, the Delta was the heart of a complex ecological web that provided crucial habitat for resident populations of wildlife, nourished marine fisheries in the Gulf of California, and formed a critical link in the Pacific Flyway for birds flying north from Central America. And it is only here that the true impacts of the obsession with wringing out every last drop of water all the way down the Colorado River ultimately become visible.

For millions of years, the Delta received the entire flow of the river. As the first round of water conservation began playing out in the 1930s and the phalanx of dams went up, that water disappeared. The graph of the river’s annual flow through those years looks like a hospital patient flat-lining.

Ed Glenn is a researcher at the University of Arizona who has extensively studied the Delta. The river ecosystems here, he says, “were shaped by the pulse flood regime that’s common on arid-zone rivers, and especially ones driven by El Niño cycles: In really wet years, pulse floods germinate the trees, and then the water retreats and those trees can live on groundwater.” Without the floods that the native cottonwoods need to germinate and reproduce, they were crowded out by invasive tamarisk. By taming the floods — nature’s ultimate form of “waste” — the dams undercut the resiliency of the Delta and turned it into a land of cracked mud and impenetrable thickets of salt-sucking tamarisk.