An experimental water release from Morelos Dam on the Colorado River this spring is regarded by scientists and environmentalists as a huge success. Seeing its waters reach the sea was a symbolic victory for river conservationists as the Colorado was made whole again, if only briefly.
The Colorado River serves as the principal drainage outlet for the southwestern United States and northwestern Mexico. In its 1,450 mile journey from the Rocky Mountains to the Gulf of California, it passes through some of the most majestic canyons and breathtaking scenery in North America, most notably the Grand Canyon. The Colorado was at one time among the mightiest rivers in the world.
The lower reaches of the Colorado River, however, have been reduced to a dried-up riverbed. It simply runs out of water in the last 100 miles of river and it has not consistently reached the sea since the 1960s. This is because fifteen dams now exist between the river’s headwaters in Colorado and its mouth in Mexico. About 90 percent of the water is diverted for hydropower and irrigation purposes, and to supply municipal drinking water to approximately 40 million people.
Beginning on March 23 and ending on May 18, operators at Morelos Dam on the United States-Mexican border released 130 million cubic meters of water into the parched riverbed below. This was a historic event for the Colorado River, as it marks the first time that water has been released for strictly environmental reasons. The experiment is part of a water-sharing agreement reached between the U.S. and Mexico known as Minute 319. Its purpose was to see what effect this pulse of water would have on the desiccated Colorado Delta.
Within the first thirty-seven miles below the dam, almost 90 percent of the water was absorbed by the sandy riverbed. On May 15, scientists watched as surface water flowed into the Gulf of California for the first time in sixteen years. By this point, the Colorado River was only a trickle of water, less 1 percent of the river’s historic flow, but it was enough for them to deem the experiment a success. The team of twenty-one researchers behind the project were pleasantly surprised. They did not expect the water to make it as far as the Gulf.
The results of the experiment are encouraging to these scientists. Research shows a 43 percent increase in green vegetation in the riverbed itself and a 23 percent increase along the banks of the riverbed, also known as the riparian zone, between Aug. 2013 and Aug. 2014. For scientists, this means that the release of water from Morelos Dam has temporarily reversed a “browning,” or decrease in green vegetation, that has been occurring in the Colorado River Delta for the past thirteen years. The team of researchers will continue to monitor the long-term effects through 2017.
It is unlikely that a similar release of water can be repeated on a regular basis because all of the river’s water is strictly allocated within the United States and the southwestern part of the country is in the midst of a long-term drought. This is unfortunate for environmentalists, who believe that this successful experiment is proof that the Colorado River Delta could regenerate itself if we would allow just a small fraction of its water to reach its natural destination.
By Dac Collins
Photo by Glenn Olsen – Flickr License