PAGE, Ariz. — Behind Glen Canyon Dam spreads a vista reincarnated. One of the West's mightiest reservoirs is in steady retreat, the deep turquoise of its waters replaced by the chalky white of canyon walls submerged four decades ago.
Five years of record-breaking drought in the Colorado River basin have drained Lake Powell of more than 60% of its water. Flows on the Colorado are among the lowest in 500 years.
Downriver, Lake Mead, the biggest reservoir in North America and supplier of water to Southern California, Arizona and Las Vegas, is little more than half full. At Mead's northern end, the foundations of St. Thomas, a little town demolished in the 1930s to make way for the reservoir, have reemerged.
The 1,450-mile-long river that greens 3.5 million acres of farm and range land and helps feed the faucets of 25 million people may within a few years lack the water to quench the West's great thirst. For the first time ever, the seven states that rely on the Colorado are confronting the possibility of a shortage.
"They've never had to face a shortage of this consequence," said Pat Mulroy, head of the Southern Nevada Water Authority that supplies Las Vegas, one of the most river-dependent cities in the Colorado basin. "When you're right up against it and facing the possibility of inadequate supplies to municipalities or farmers or jeopardizing recreation values, these are very tough choices."
The states are meeting now to try to figure out how they will deal with a shortage if the drought continues. As with everything else on the heavily regulated Colorado, the answers will be found in a complex tangle of law and politics.
If the law of the river was strictly followed, cuts would be made according to a hierarchy of water rights, with Arizona, Nevada and the upper basin states of Colorado, Wyoming and Utah taking the first hits. California, which gets about 14% of its statewide water supply from the river, has some of the most senior rights on the Colorado and is in a comparatively good position.
But the states may try to avoid triggering cuts. One approach would be for utilities to buy water from farmers and growers -- who use 80% of the river's water -- and send it to cities.
"With voluntary transfers you can easily take care of the big urban needs in the lower basin with compensation to farmers, and you don't have to dry up agriculture to do that," said Robert Johnson, the lower Colorado regional director for the U.S. Bureau of Reclamation, which operates the dams and reservoirs that make up the river's vast plumbing system.
"I don't want to downplay the importance of the drought," he said. "But my own opinion is we'll figure out how to deal with it."
If the states don't come up with a plan, the federal government will. "The [Interior] secretary will be forced to take action within three years, and potentially within two, if the states haven't solved the problems themselves," Bennett Raley, assistant secretary for water and science for the U.S. Department of the Interior, warned last spring.
Nowhere is the drought as dramatically evident as at Powell, one of the last major reservoirs constructed in the West. As the water recedes, the stunningly blue desert lake, loathed by conservationists for drowning a majestic canyon in the mid-1960s, is disinterring its past. Glen Canyon is reemerging, caked with white mineral salts left by the backed-up waters of the Colorado.
At Warm Creek Bay, one of Powell's many arms, the lake's decline can be measured by the height of the advancing green forests of salt cedar, an invasive shrub that is quickly staking its claim to the emerging lake bottom. The exposed mud has puckered into salt-crusted chunks, a loose puzzle of fudge-like pieces.
The last time it was full, in 1999, the Powell reservoir extended for 186 miles upriver. It is now 145 miles long. The lake level has dropped nearly 130 feet. If it continues its downward creep, there may not be enough water to generate hydropower in two years.
By 2007 or 2008, Powell could sink below the dam's intake tubes. At that point, the lake would be more than three-quarters empty. Releases from the reservoir couldn't be made until nature provided more water. This year, nature delivered half the normal inflow. In 2002, one of the driest years ever recorded on the Colorado, it was a quarter of the norm.
As the reservoir's levels plunge, so does hydropower production. At Lake Mead, Hoover Dam's generating capacity is down 17%. At Glen Canyon Dam, it has dropped 30%. The Western Area Power Administration, which distributes electricity from the dams, is cutting deliveries and expects to spend more than $30 million this year buying power to replace the lost Glen Canyon energy.
Meanwhile, the National Park Service is spending millions of dollars chasing the retreating waters at Mead and Powell, moving stranded recreation facilities and extending boat ramps that now end in cracked mud.