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The Accidental Wetland in the Colorado Delta

This post is part of a series on the Colorado River Delta. Traveling south from the Mexican border town of San Luis Rio Colorado, we stop about 20 miles (32.2 km) from the Upper Gulf of California.  It feels like the middle of nowhere. We’re surrounded by vast stretches of cracked, dried-out mudflats layered with...

This post is part of a series on the Colorado River Delta.

Traveling south from the Mexican border town of San Luis Rio Colorado, we stop about 20 miles (32.2 km) from the Upper Gulf of California.  It feels like the middle of nowhere.

We’re surrounded by vast stretches of cracked, dried-out mudflats layered with salt.  Although we’re in the historical floodplain of the mighty Colorado River, there is no water, no vegetation, and no sign of life at all.Colorado River delta series

“Thousands of acres look just like this,” says Osvel Hinojosa Huerta, an ecologist with the Mexican conservation organization, Pronatura Noroeste, and a National Geographic Explorer.

As we travel on through the barrenness, I take in what the delta has become from eighty years of damming and diverting this iconic river.

Then suddenly – like a mirage in the desert – an oasis appears.  Marshes of cattails and bulrushes and a maze of lagoons open up before us.  As if out of nowhere, birds come into view.  Fishing boats sit hitched to a wooden dock.

We have arrived at La Ciénega de Santa Clara, one of the largest and most significant wetlands in the entire Colorado River Basin.  It would be no exaggeration to say it is one of the most important desert wetlands in all of North America. Its 40,000 acres (16,000 hectares) of marshes and mudflats support 280 species of birds, including the elusive and endangered Yuma clapper rail. Some 300,000 migratory birds spend their winters here.

It is a magnificent, almost magical marshland – and it was created completely by accident.

A Wetland’s Humble Beginnings

On an ordinary day in 1977, Juan Butrón, who resides in the nearby community of Ejido Luis Encinas Johnson, stumbled upon a large canal transporting water into the delta not far from his home.  He followed it to its terminus.  There, he was astonished to find a shallow lake spread out before him. It had formed where the canal discharged salty drainage water into the barren delta.

Soon, fish arrived.  Butrón, his family and others from the local community began to picnic, boat and catch fish there.

Before long, cattails and bulrushes sprung up, turning the lake into a maze of marshes and lagoons.  By 1988, the cattail marsh spanned about 7,000 acres. A dozen years later, when I first visited the Ciénega, the marshes had nearly doubled in size.  Today, they still cover about 14,000 acres of what had previously been desiccated earth.

“I saw her growing,” Butrón said of the Ciénega. “I brought my sons here when they were young. The Ciénega is part of my family.”

The canal Butrón discovered originates in the Wellton-Mohawk Irrigation and Drainage District, a farming region in southern Arizona.  In the sixties, Mexican officials complained to their northern neighbor that the salty drainage from the district, which was being mixed with Colorado River water and delivered to Mexico as part of its river allocation, was killing farmers’ crops.

U. S. officials responded by building a 60-mile long canal and discharging 108,000 acre-feet (equal to 0.7 percent of the Colorado’s historic annual flow) of agricultural wastewater from the irrigation district into the delta each year.

Little did they know that they would inadvertently create one of the most amazing and ecologically significant wetlands in all of North America.

“It is so resilient,” says Hinojosa Huerta, who has been studying the delta for more than fifteen years.  “Life just wants to return here.”

Rich Diversity of Life

We climb into boats and ply the marshes. American coots glide along the water’s surface. A small riot of bird sounds erupts from the cattails.  Out on the sandbars, black-neck stilts do their circus walks and long-billed dowitchers poke deep into the mud for snacks.

Then, from some distant corner of cattails comes a “keck, keck, keck, keck.” Osvel turns to me, and whispers, “a clapper rail.”

Hinojosa Huerta is an expert on the Yuma clapper rail, now an endangered bird due to the loss of its habitat along the Colorado River and Delta.  Every year since 1998, he has organized surveys to assess Mexico’s clapper rail population. He estimates that some 6,000-7,000 individuals live here in the Ciénega, about three-quarters of the global population.

As the setting sun turns the desert sky into a quilt of brilliant reds and oranges, a pair of northern shovelers flies by.  Huge flocks of swallows loop and swoop through the air, as if crowd-sourcing their fun.

For just a moment I am carried back to 1922, the year the great conservationist Aldo Leopold canoed through this portion of the delta with his brother Carl. I savor a taste of the “milk and honey wilderness” and “land of a hundred green lagoons” that Leopold described years later in a moving essay in his masterwork, A Sand County Almanac.

The river that for Leopold was “nowhere and everywhere” as it meandered its way toward the sea is long gone.  But here in La Ciénega de Santa Clara— sustained by salty farm drainage that could be cut off in a flash–- is a precious reminder of the delta’s former glory, and honest hope for its resurrection.

Help restore water to the Colorado River by joining Change the Course. Sign up online or text ‘River’ to 77177.

Special thanks to Silk and Coca-Cola, Charter Sponsors for Change the Course. Additional funding generously provided by the Walton Family Foundation.


Sandra Postel is director of the Global Water Policy Project and Freshwater Fellow of the National Geographic Society. She is the author of several acclaimed books, including the award-winning Last Oasis, a Pew Scholar in Conservation and the Environment, and one of the “Scientific American 50.” She is co-creator of Change the Course, the national freshwater conservation and restoration campaign being piloted in the Colorado River Basin.

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Meet the Author

Sandra Postel
Sandra Postel is director of the Global Water Policy Project and author of Replenish: The Virtuous Cycle of Water and Prosperity. From 2009-2015, she served as Freshwater Fellow of the National Geographic Society. Sandra is also co-creator of Change the Course, the national water stewardship initiative awarded the 2017 US Water Prize for restoring billions of gallons of water to depleted rivers and wetlands. The recipient of several honorary degrees, she works to bridge science, policy, and practice to promote innovative ways of securing water to meet both human and ecosystem needs.