Supplies in New Mexico, one of seven states that depend on the river’s water, will be untouched by the moves. But experts said the move is a warning that demand is outstripping supply throughout the basin.
“What we’re facing here is a truly historic drought,” said Assistant Secretary of the Interior Anne Castle, speaking at a meeting of Colorado River managers at which the shortage declaration was a major topic of discussion.
The last 14 years are the driest in a century of record keeping, Castle said, and among the driest such periods in more than a thousand years of tree ring records.
Castle said natural drought, made worse by climate change, requires “new thinking” to deal with the region’s water problems.
New Mexico uses Colorado Basin water for farming and cities in the San Juan Basin in the northwest corner of the state. In addition, Albuquerque, Santa Fe and other New Mexico communities use Colorado water imported via the San Juan-Chama project.
Friday’s announcement is the result of a historic deal among the seven Colorado River Basin states signed in 2007 that allowed the federal government to hold back water if Lake Powell drops too low.
That has the practical effect of protecting New Mexico’s supplies for the foreseeable future, because Lake Powell acts as a sort of savings bank for states in the Colorado’s Upper Basin, said Estevan López, head of the state’s Interstate Stream Commission.
Under the 2007 deal, the Upper Basin states agreed to share extra water with the downstream states of Arizona, Nevada and California during wet years in exchange for an agreement to hold water back in Lake Powell during dry years like this one.
“It’s playing out just the way it was supposed to,” López said.
As downstream supplies dwindle as a result, Nevada and Arizona would face the first shortages, though the initial cutbacks in those states would be small. “This is an Arizona and Nevada problem,” said Doug Kenney, a professor at the University of Colorado.
But New Mexicans should not take too much solace in the fact that they have avoided this round of cutbacks, Kenney said, because the curtailment is a sign that water users across the Colorado River Basin continue to use water faster than nature is providing it.
“Supply and demand are out of balance,” Kenney said, “and it’s not a problem that can be ignored forever.”
“This is kind of a reality check for everyone,” López said.