colorado river

US, Mexico To Sign Landmark Colorado River Agreement

Nov 19, 2012
Laurel Morales

The Hoover Dam was built to control the powerful Colorado River, which for many years flooded farms and cities.

Randall Babb / Arizona Game and Fish Department

There was a time when scientists feared the demise of an ugly little fish called humpback chub, which has lived in southwestern rivers for millions of years. One of its last holdouts is in the Grand Canyon section of the Colorado River at a major tributary, the Little Colorado. Glen Canyon Dam took its toll on the little fish, and by the late 1990s, its population plummeted to a few thousand.

But these days, the humpback chub appears to be making a comeback.

Laurel Morales

The Colorado River is about to run wild again, at least a couple times a year. In May, Interior Secretary Ken Salazar approved a series of simulated floods -- releasing huge amounts of water and sediment from the Glen Canyon Dam over the next several years. It’s all part of a long-studied effort to restore the river environment downstream.

Five boats recently launched a two-week Grand Canyon river trip. The group of tourists paddled white-water rapids, hiked side canyons and camped at river’s edge.

Over the past hundred years, people have introduced dozens of non-native fish species into the Colorado River and its tributaries. During that time, populations of native fish species have dropped, in some cases dramatically. It’s easy to guess at the causes of native species decline, like predation and competition for food. But it’s far more difficult to prove.

Photo courtesy Arizona Dep't of Water Resources.

Mexico and the United States are working toward a broad package deal that would help revive the Colorado River Delta.

Seven years ago, the U.S. began working on the project to line an earthen portion of the All-American Canal in Imperial Valley and send the saved water to San Diego. Many in Mexico and the U.S. opposed the lining, saying it prevented seeping water from reaching fields and wetlands in Mexico. The lining project was completed in 2010.

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