The recent visit by Secretary of Interior Ken Salazar to the Arkansas Valley prompted a discussion of the future management of the Colorado River. Here’s a report from Chris Woodka writing for The Pueblo Chieftain. From the article:
The Parks Service is apparently concerned about the levels at Lake Mead, which is a popular recreation area as well as a source of water supply and electric power for California, Arizona and Nevada. Prolonged drought and increased demand have caused levels to drop and it can cost millions of dollars to move marinas on the lakes. The service has asked for more authority on the operation of Glen Canyon Dam, which releases water from Lake Powell through the Grand Canyon and into Lake Mead. The states are objecting to broadening the authority under past acts of Congress and Interior policies. “The interim guidelines [for drought managment] offer a secure foundation on which to build the important initiatives necessary to achieve greater flexibility in the development and management of the Colorado River water supply,” the states wrote in the letter.
The Arkansas Basin imports an average of about 131,000 acre-feet from the Western Slope each year, or about 18 percent of the supply of water when measured against the high point of flows on the Arkansas River at Avondale. The amount varies widely, however, and Front Range water users are wary about what could happen if there were a call on the river from downstream states.
The Colorado Water Conservation Board is looking at studies both to quantify how much Colorado River water is still available to use within the state and to determine which rights would be curtailed if the state was limited in how much water it could divert. “We, as a state, need to come to a better understanding of what water is available under what conditions,” [Alan Hamel, executive director of the Pueblo Board of Water Works] said. “If there is a call on the Colorado River, how do we manage the call?”
Such a call would not be as simple as a traditional river call in Colorado, where junior diverters on one stream are shut off. The Colorado River system is complex, with some reaches that are fully appropriated, reaches where additional water is used to protect endangered species and others that have never been administered under state water laws. Transmountain diversions are further complicated by the need to maintain certain flows downstream. In some years, not all of the water called for in a decree can be taken, while in some emergency situations the transmountain diverters have been asked to take even more water to prevent flooding on the Western Slope.
More Colorado River Basin coverage here and here.