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Overtaxed Colorado River bathed with new life

Waters flow through dry channels near border

In the shadow of the San Luis Rio Colorado bridge, which carries Mexico's Federal Highway 2 east-west along the U.S.-Mexico border, the Colorado River is usually a dusty channel, full of flour-like sediment. 

However, on Thursday, the bone-dry river bed was soaked, the water deep enough for swimming. A crowd gathered beneath the bridge and celebrated the sudden appearance of flowing water. 

Orne Mesa, from Baja Mexico, smiled as he held his three-year granddaughter Alondra, so she could splash in the current. 

Nearby, Edna Gamez watched her two boys throw small rocks into the water. "I've never seen the water like this," she said. "It's beautiful." 

The surge of water is the result of an agreement between the United States and Mexico to release millions of gallons from Mexico's Morelos Dam, across the border just west of Yuma, into the river channel as part of a five-year restoration project.

Over-allocated and cordoned by dams, the Colorado River is a trickle by the time it finishes its 1,700-mile trek to the Gulf of California. 

The release, or "pulse" of water, started on Sunday, when the dam's gates were lifted releasing 700 cubic feet of water per second, to simulate the water-flow the Colorado River would normally get from spring snowmelt. By Thursday, the pulse had reached its peak, as 4,200 cubic feet of water gushed through the gates every second. 

With the dam as a backdrop, officials from the United States and Mexico marked the occasion with a press conference. 

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"There's an optimism that despite the crises of drought, different stakeholders can come together on big solutions to restore a way of life," said Michael Connor, Deputy Secretary of the U.S Department of the Interior. "And ensure that the Colorado River is protected for generations to come." 

From March 23 through May 18, about 105,000 acre-feet (each enough water to cover a football field with water, one foot deep) will be released into the Colorado River delta, representing less than one percent of the annual flow of the river. 

This "pulse" will not affect U.S. water supplies along the Colorado, which supplies water to farms in Yuma and Imperial Valley, Calif. as well as the thirsty cities of Phoenix, Tucson, and Las Vegas. Instead, the water comes from allocations of water that Mexico hasn't used because of a 2010 earthquake, which damaged irrigation systems in the Mexicali valley. 

As part of the agreement, an addendum to a 1944 treaty between the U.S. and Mexico called Minute 319, the United States has held water intended for Mexico in Lake Mead as part of the agreement signed in 2012. Normally, the United States sends about 1.5 million acre-feet per year past the Yuma valley. 

"We get the ability to store more water, which keeps Lake Mead at a higher level, so this delays any shortages that we might have," said Connor. "We're interested in keeping Lake Mead propped up, so the real benefit here is we can plan for these environmental benefits, in the long term with what we need, but we can also keep the system as full as possible in the short term."  

Lake Mead is the bellwether of water supplies in the southwest United States. Should the lake's level drop below 1,075 feet, officials with the Bureau of Reclamation will declare a shortage, cutting the water available to southwestern states. Under current law, Arizona would lose 17 percent of its water. 

The United States will send $21 million to repair the Mexican water system, including $10 million from the water districts for Arizona, Las Vegas and Los Angeles, the rest coming from the federal government. The Central Arizona Project will provide $2.5 million in this agreement, getting a share of water around 24,000 acre-feet. Mexico will provide 95,000 acre-feet for use by the three American water districts, while allowing 53,000 acre-feet to be used along the Colorado River delta. 

The pulse flow was possible because conservation has saved nearly 300,000 acre-feet, said Connor. "We'll use some water, but we'll also store some of Mexico's allocation," he said. 

By saving more water in Lake Mead, the United States can avoid shortages, he said. 

This means U.S. cities can have their share of water, and Hoover Dam can keep making electricity. Without this additional water, it's increasingly likely that some shortage will be announced before 2020. 

In 2010, the water level in Lake Mead declined precipitously to 1,078-feet leaving a "bath tub ring," a sign of a dryer, tougher future for the river. Despite a better snowpack last year, the Colorado River continues to endure a 14-year drought. 

Past the pulse, restoration efforts in Mexico

One the first day of the pulse, the river's waters found their way 15 miles downstream, but by Thursday that flow had slowed to a modest quarter-mile per hour. As the river seeks out new pathways in the channel, it will eventually hit the Laguna Grande, a restoration area developed by the Sonoran Institute around 40 miles south of the Morelos Dam. 

The Laguna Grande is an attempt to recover land around the delta, once covered with dense strands of willows and cottonwoods. However drought and invasive salt cedar trees—originally part on a anti-erosion effort in the United States—have decimated the area. 

Francisco Zamora, the director of the Sonoran Institute's delta legacy program, points out the Laguna on a map. Here a smattering of greenery is cut by the brown of the thorny desert and the dry river.

"We want to reconnect the meanders," he said. 

To do this, the Sonoran Institute in a partnership with ProNatura has planted more than 80,000 trees, clearing the land and mulching the salt cedars. Already, the partnership's effort has restored around 180 acres of riparian habitat, with plans to cover the entire restoration area — around 1,200 acres — with the same dense woods. This will include another 96,000 more trees. 

Already, they are seeing results. 

Tomás Rivas, a marine biologist and restoration specialist with the Sonoran Institute, notes that bobcats, raccoon and several kinds of bird species have reappeared in the restoration area, along with beavers and coyotes. The trees grow rapidly — the tallest are nearly 50 feet high, he said. While the partnership has uses water from Mexico's interwoven canal system, the pulse flow is exciting chance to build a stronger foundation for the new forests. 

"The flow helps elevate the water table," he said. "All this work will bring the delta back to what it was 100 years ago." 

As Minute 319 is set to expire in 2017, the partnership has worked to purchase water rights in Mexico's open water market, in a coalition with the four other environmental groups, including the Nature Conservancy, the Environmental Defense Fund, the National Fish and Wildlife Foundation, and the Redford Center. By purchasing water, the coalition hopes to augment the eight-week pulse with a "base flow" of more than 53,000 acre-feet over the next four years to four key restoration sites, including the Laguna Grande. 

"This is really unusual," said Taylor Hawes, director of the Nature Conservancy's Colorado River program. "Previous environmental efforts haven't been built on partnerships that include all the stakeholders with this kind of focus on understanding what everyone really needs." 

"The pulse flow really minimizes the impact of droughts for everyone," she said. "It's a mix of incentives that really changes the dynamic for water use along the Colorado." 

The next four years will be crucial for understanding how the pulse flow supports the river delta. Ultimately, the coalition hopes to bring the river back to its something akin to its historic levels, bringing life back to the Colorado delta. Today, however, is a time for celebration. 

Back near the Highway 2 bridge, Peter Culp stands at the new river's banks. A Phoenix-area attorney, Culp worked for more than a decade on negotiations to make the pulse flow possible.

 "It's just such a thrill to really see this whole thing come together," he said, watching as families park beneath the bridge and several children play in the water. "It's just really inspiring to see people enjoy the river." 

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Paul M. Ingram/TucsonSentinel.com

Four girls wade into the newly quenched Colorado River channel on March 27, part of the 'pulse flow' — an experimental release of millions of gallons of water from the Morelos Dam.