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A river runs through it, again

By: George Patten

An extraordinary ecological restoration effort is currently happening in Mexico, and if the star-studded (and brilliant) public service announcement featuring Will Ferrell, Robert Redford, and Kelly Slater is any indication, recent efforts to revive a dried up portion of the Colorado River delta are, in the words of Ferrell’s character Ron Burgundy, “kind of a big deal”.

for the first time in decades this 70-mile stretch of the Colorado River will flood.  Map courtesy of Wikipedia.

For the first time in decades this 70-mile stretch of the Colorado River will flood. Map courtesy of Wikipedia.

The Colorado River is one of the most celebrated drainages in the West – forming out of the high Rockies and flowing over 1400-miles through places like the Grand Canyon. But few realize that the river runs dry before reaching its historic delta in the Gulf of California. The 70-mile stretch of river south of the U.S. border once flowed into a rich delta ecosystem, but as a result of numerous pressures on the river’s water supply the delta has become dry and barren.

For the first time in decades the river is coursing its way towards the Gulf thanks to a binational agreement between the U.S. and Mexico. The historic and unprecedented restoration event involves a one-time release or “pulse flow” into the lower reaches of the river in an effort to revive the former ecological conditions of the delta.

Colorado River running through the Grand Canyon. Photo courtesy of George Patten.

Colorado River running through the Grand Canyon. Photo: George Patten.

The Colorado River drains an enormous area in the western U.S. and traverses multiple states before crossing the border into Mexico. The expansive and mostly arid Colorado River watershed is highly influenced by annual snowpack in the northern portion of the basin. The River is also one of the most valued and managed water sources in the western US, with multiple dams and massive engineering projects and serves as a key source of water to multiple western states. Numerous compacts and regulations manage and allocate flows within the river between northern and southern basins, as well as between the U.S. and Mexico – collectively known as the Law of the River. Despite measures to help manage use of the river’s annual flows, increasing demand, impoundments, and periods of drought have contributed to the drying of the river prior to reaching the delta, which has in turn affected the natural ecology of the system.

Water released from the Moreles Dam on the first day of the pulse. Image courtesy of John Fleck.

Water released from the Morelos Dam on the first day of the pulse. Image courtesy of John Fleck.

The terms for the pulse flow were established as part of a binational agreement between the U.S. and Mexico, called Minute 319. The release of the pulse, which began on March 27 and will flood the region with over 100,000 acre-feet of water, mimicking high spring water flows that formerly occurred naturally in the basin.

Several groups are monitoring the status and impacts of the pulse flow, including the effects to ecosystems and wildlife in the Colorado River delta. The high pulse flow is designed to help support establishment of riparian vegetation and trees, such as cottonwoods and willows. Riparian birds and other wildlife are also likely to benefit from the flows through improved habitat and resource availability.

Although the event appears to be one-time, it sets the stage for future conservation efforts and marks a shift in conservation and resource management priorities for the Colorado River basin. According to the International Boundary and Water Commission, the pulse is part of a “broad package of cooperative measures for Colorado River water management by the United States and Mexico that protects both countries’ interests in this essential natural resource.”

 

References:

Bureau of Reclamation: Lower Colorado Region – Law of the River. Bureau of Reclamation: Lower Colorado Region – Law of the River. U.S. Department of the Intentior, Mar. 2008.
Colorado River Begins Flooding Mexican Delta. KPBS Public Broadcasting. Ed. Associated Press. N.p., 27 Mar. 2014. Web.
Commission Marks Historic Environmental Flow In The Colorado River. International Boundary and Water Commission United States and Mexico, 27 Mar. 2014. Web.
Postel, Sandra. Monitoring the Pulse of the Colorado River. News Watch. National Geographic, 5 Apr. 2014. Web.

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