The Colorado System Runs Dry

“went to the river
to water my hoss;
couldn’t find that river
so I rode clean across”

cowboy song

The Colorado river system is not going to fulfill its legal obligations, according to an excellent article by Tom Kenworthy at ClimateProgress.

Lake Powell is the giant reservoir on the Utah-Arizona border that backs up behind Glen Canyon Dam and is the linchpin for managing the Colorado River. The Colorado basically makes modern life possible in seven western states by providing water for some 40 million people and irrigating 4 million acres of crops. It is also depended upon by 22 native American tribes, 7 national wildlife refuges and 11 national parks.

As soon as Monday, the federal government’s Bureau of Reclamation will announce the results of some very serious number crunching and model running focused on falling water levels in Lake Powell. It is widely expected that the bureau will announce that there is a serious water shortage and that for the first time in the 50-year-history of the dam, the amount of water that will be released from the reservoir will be cut. Not just cut, but cut by 750,000 acre feet — an acre foot being enough water to cover an acre one foot deep. That’s more than 9 percent below the 8.23 million acre feet that is supposed to be delivered downstream to Lake Mead for use in the states of California, Nevada and Arizona and the country of Mexico under the 81-year old Colorado River Compact and later agreements.

It will be, in the somewhat dry appraisal of Anne Castle, the assistant secretary of the Interior for water and science who oversees the bureau, “very unusual.”

Lake Powell, and its downstream cousin, Lake Mead — formed by Hoover Dam — are the two largest reservoirs in the U.S. They are the main plumbing fixtures for dividing up Colorado River water under a complex set of agreements known as the Law of the River. The Colorado River Compact is the most important of those agreements, and requires that the lower basin states and upper basin states (Colorado, New Mexico, Utah and Wyoming) each get 7.5 million acre feet a year. Mexico gets another 1.5 million under a 1944 treaty.

All good in theory, but the river was divided up in the 1920’s, a wet period when river flows were high. Times, and flows, have changed.

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  1. Pingback: Another Week of Climate Instability News, August 18, 2013 – A Few Things Ill Considered


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