Saving a river along the US-Mexico border

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Arizona and the Mexican state of Sonora are divided by an international border. But they are also united by the Santa Cruz river. In recent years, the river has become dry and now government agencies and citizens groups on both sides are struggling to preserve this precious waterway. Lorne Matalon reports.

MARCO WERMAN: Our next story is about two other neighboring countries, our own and Mexico. We're heading just across our Southern border, as we follow the Santa Cruz River or to be more precise, what's left of it. Lush vegetation and trees used to grow along the Santa Cruz but increasing populations along the river demanded increasing amounts of water. Now some groups are working to restore a healthy flow of water. The World's Lorne Matalon reports from the banks of the Santa Cruz River in Sonora, Mexico.

LORNE MATALON: Just south of the U.S. border, the Santa Cruz River is a dust bowl, a scarred ditch, tapped dry by the booming twin cities of Nogales, Mexico and Nogales, Arizona. Not long ago, people waded in and held baptisms in the river. Today it looks like fire has destroyed the river bed and the trees beside it. But it's a very different story a couple of hours farther into Mexico. San Lazaro, Mexico, population 600 sits on the floor of a remote valley, criss-crossed by worn paths carved into the boundless Sonoran Desert. It's where the Santa Cruz starts winding its way north towards the U.S. and it's where 20 year old Arturo Alvarez leads a group of young people working on a restoration team. We're watching bird migration patterns, Alvarez says. The group is known as Los Halcones, the Hawks, and it's also monitoring the river's temperature and the health of the vegetation lining its banks. Less than a decade ago, little took root here. The protective underbrush and cottonwood and mesquite saplings had been trampled by cattle and horses but Los Halcones have fenced off two miles of the river and saplings are now abundant. The work here is done to preserve the river, says Alfonso Gonzales, a 44 year old sheep farmer with grizzled hands that speak to a life on the land. He collects Los Halcones' data and shares them with the Tucson, Arizona based Sonoran Institute. The groups are key parts of a bi-national effort to salvage a river crucial to both countries. Los Halcones also shares its data with the International Boundary and Water Commission, the bilateral agency that works to resolve water problems along the border. Agronomist Gilberto Solis Garza is an advisor to the commission. He also works with Los Halcones and the Sonoran Institute. Solis says that Santa Cruz is a symptom of stress on the border region's water supply.

GILBERTO SOLIS GARZA: And that is why the effort to improve El Rio Santa Cruz is so important. Farmers, ranchers, industry and families, they have, all take in too much water and water is not an infinite resource, even though people think the supply will never end.

MATALON: Just a few miles north of San Lazaro, the supply does end as the Santa Cruz passes through the crowded border region. But not far beyond that, in the U.S., the river makes a dramatic comeback. From less than a thousand feet up, pilot and conservationist, Dan Meyer, points out a stretch of river where a sun-bleached ribbon of sand is suddenly replaced by lush, green ribbons of cottonwood, willow and mesquite trees.

DAN MEYER: Where we are now you can see a very healthy part of the river.

MATALON: But it's a bit of an illusion.

MEYER: What we're seeing here is ground water from what's being used in Nogales, Mexico.

MATALON: The water on this stretch of the Santa Cruz comes from a waste water treatment plant. The plant is in the U.S. but it treats sewage piped from Mexico. Biologist Amy McCoy of the Sonoran Institute says the cross-border waste water transfer is helping revive a major part of the river and the local ground water.

AMY McCOY: The effluent flows through the stream bed and it infiltrates into the ground water tables. It's cleaned and it's filtered by the soil of the river and the roots of the trees. It returns to the aquifer and ultimately becomes drinking water again.
MATALON: McCoy says pressure on the Santa Cruz is growing as the river is squeezed between increasing demand and a likely further drop in rainfall due to climate change. So our options are to adapt and on the Santa Cruz River, one of the ways that we can do that is by looking at ways to reuse water.

MATALON: But it's not a sure thing that the cross-border waste water deal with continue. Nogales, Mexico has threatened to stop sending its affluent to Arizona unless it gets paid for the water. Negotiations are now underway. One American negotiator hopes a new deal will fund an upgrade of the Mexican city's rundown water system. Back in Mexico, rancher Ventura Rivera Medina lives on a tributary of the Santa Cruz. He might benefit from such a project. But he's not waiting. Working with the Sonoran Institute, Median has built three foot high rock walls to capture and channel precious rain water. He uses what he needs and diverts the rest back into the river. Rivera says ranchers on both sides of the border need to take the initiative to conserve water and restore the Santa Cruz. We're trying to show everyone that what we're doing here works he says, but we really need both governments to support this work because ranchers don't earn enough to do it by themselves. Negotiations that could bring more government support for the restoration effort are progressing slowly. While the Santa Cruz continues to live two lives as a dried out skeleton of a river and a restored waterway, venerated by a new generation of river activists on both sides of the border. For The World, I'm Lorne Matalon, Sonora, Mexico.

WERMAN: Pictures of the Santa Cruz are at