Great Rivers Are Worthy Of Great Restoration Projects

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The Colorado River delta in Baja California is now a mosaic of largely dried-up river channels and tidal salt flats. TED WOOD

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Downstream from the Morelos Dam, the Colorado River delta now runs dry before reaching the Gulf of California. MAP BY DAVID LINDROTH

When the first couple of stories about the Colorado River ran in Yale e360, it was difficult to imagine how much more there might be to say about it. But now the last article in the series, Restoring the Colorado: Bringing New Life to a Stressed River, provides an example of saving the best for last:

The Colorado River has been dammed, diverted, and slowed by reservoirs, strangling the life out of a once-thriving ecosystem. But in the U.S. and Mexico, efforts are underway to revive sections of the river and restore vital riparian habitat for native plants, fish, and wildlife. Last in a series.

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The Morelos Dam on the U.S.-Mexico border, where the Colorado’s remaining water is diverted to cities and farms in Mexico. SUPPORT FOR AERIAL PHOTOGRAPHS PROVIDED BY LIGHTHAWK

From the air, the last gasp of the Colorado River is sudden and dramatic. The pale green river flows smack into the Morelos Dam on the U.S.-Mexico border, and virtually all of it is immediately diverted into a large irrigation canal that waters a mosaic of hundreds of fields — alfalfa, asparagus, lettuce, and other vegetables, their vivid green color clashing against the sere desert. The slender thread of water that remains in the Colorado’s channel continues to flow south, but is soon swallowed up by a sea of sand, far short of its delta, which lies 100 miles farther on.

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A fisherman on the upper Colorado River in northern Colorado. Low water flows have endangered fish populations and led last year to the closing of parts of the river to fishing.

The Colorado River once surged through the delta during high flows, carrying so much water at times that shallow draft steamboats chugged hundreds of miles up the river into the U.S. with loads of freight. The water in the delta nourished a vast fertile landscape, a fitting end to a river known as the Nile of North America.

“The river was everywhere and nowhere,” the naturalist Aldo Leopold wrote during a 1922 canoe trip to the delta, describing the waterway as it ebbed, flowed, braided, and stalled into pools, nourishing a rich and diverse ecosystem of “a hundred green lagoons,” a “milk and honey wilderness” with thick stands of cottonwoods and willows that provided habitat for hundreds of species of birds. The delta’s marshes, mudflats, and white sand beaches were home to clapper rails, bitterns, mallards, teal, and clouds of egrets.

Bobcats, puma, deer, and wild boar wandered the delta’s forests. Leopold was searching for the jaguar that roamed there, but didn’t see any. Continue reading

The Future Runs Through It

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After two decades of drought, Lake Mead in Nevada is just 40 percent full. TED WOOD

Thanks to Jim Robbins and Yale e360 for this second installment, and especially to Ted Wood for photography as visually compelling as the implication of the story:

CRISIS ON THE COLORADO: PART II

On the Water-Starved Colorado River, Drought Is the New Normal

With the Southwest locked in a 19-year drought and climate change making the region increasingly drier, water managers and users along the Colorado River are facing a troubling question: Are we in a new, more arid era when there will never be enough water?

 

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Scientists at the University of Arizona are using tree rings to study centuries of drought conditions in the Colorado River Basin.

In the basement of the University of Arizona’s Laboratory of Tree-Ring Research, the fragrant smell of pine hangs in the air as researchers comb through the stacks of tree slabs to find a round, 2-inch-thick piece of Douglas fir.

They point out an anomaly in the slab — an unusually wide set of rings that represent the years 1905 to 1922. Those rings mean it was a pluvial period — precipitation was well above average — and so the trees grew far more than other years.

“In 1905, the gates opened and it was very wet and stayed very wet until the 1920s,” said David Meko, a hydrologist at the lab who studies past climate and stream flow based on tree rings. “It guided their planning and how much water they thought was available.”

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Mark Harris, a water manager in Grand Junction, Colorado.

The planning was that of the states that share the water of the Colorado River. Worried that a burgeoning California would take most of the water before it was fairly divvied up, representatives from the other Colorado River Basin states, presided over by U.S. Secretary of Commerce Herbert Hoover, came together in 1922 to develop an equitable apportionment. They looked at flow measurements and figured that the river contained an average of 15 million acre-feet. They divided the Colorado River states into two divisions – the upper basin and the lower basin, with the dividing line in northern Arizona near the Utah border. The upper basin states — Utah, Wyoming, Colorado, and New Mexico — agreed not to take more than a total of 7.5 million acre-feet and to allow the other half to flow south to the lower basin. The agreement they signed was called the 1922 Colorado River Compact, also known as the Law of the River. Continue reading

Colorado River’s Future

Thanks to Jim Robbins and Yale e360:

CRISIS ON THE COLORADO: PART I

The West’s Great River Hits Its Limits: Will the Colorado Run Dry?

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The headwaters of the Colorado River are in a marshy meadow in Rocky Mountain National Park.

As the Southwest faces rapid growth and unrelenting drought, the Colorado River is in crisis, with too many demands on its diminishing flow. Now those who depend on the river must confront the hard reality that their supply of Colorado water may be cut off. First in a series.

The beginnings of the mighty Colorado River on the west slope of Rocky Mountain National Park are humble. A large marsh creates a small trickle of a stream at La Poudre Pass, and thus begins the long, labyrinthine 1,450-mile journey of one of America’s great waterways.

Several miles later, in Rocky Mountain National Park’s Kawuneeche Valley, the Colorado River Trail allows hikers to walk along its course and, during low water, even jump across it. This valley is where the nascent river falls prey to its first diversion — 30 percent of its water is taken before it reaches the stream to irrigate distant fields.

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The Colorado flows 1,450 from its source in Colorado to the southwest, ending just short of the Gulf of California. MAP BY DAVID LINDROTH

The Never Summer Mountains tower over the the valley to the west. Cut across the face of these glacier-etched peaks is the Grand Ditch, an incision visible just above the timber line. The ditch collects water as the snow melts and, because it is higher in elevation than La Poudre Pass, funnels it 14 miles back across the Continental Divide, where it empties it into the headwaters of the Cache La Poudre River, which flows on to alfalfa and row crop farmers in eastern Colorado. Hand dug in the late 19th century with shovels and picks by Japanese crews, it was the first trans-basin diversion of the Colorado. Continue reading