As the Colorado River Shrinks, Washington Prepares to Spread the Pain

But the money came with a catch. In exchange for their support, California lawmakers insisted on a provision that their state’s water rights take precedence over the aqueduct.

If Arizona could have foreseen that climate change would permanently reduce the river’s flow, it might never have agreed to that deal, said Tom Buschatzke, director of the state Department of Water Resources.

Because of its lesser rights, Arizona has taken the worst part of recent rounds of voluntary cuts. The state’s position now, Buschatzke said, is that everyone should make a meaningful contribution and that no one should lose everything. “That’s an equitable result, even if it doesn’t necessarily strictly follow the law.”

There are other arguments in favor of Arizona. Approximately half of the water delivered through the Central Arizona Project goes to Native American tribes, including those of the Gila River Indian Community, which is entitled to 311,800 acre-feet per year.

The United States cannot cut off that water, said Gov. Stephen Roe Lewis of the Gila River Indian community. “That would be a rejection of the trusteeship obligation that the federal government has for our water.”

In an interview this week, Tommy Beaudreau, an undersecretary of the Department of the Interior, said the federal government would consider “equity, public health and safety” when weighing how to distribute the reductions.

The department will compare California’s preference to base cuts on the age of water rights with Arizona’s suggestion to cut allocations so that they “meet the basic needs of communities in the lower basin,” Beaudreau said.

“We are in a 23-year period of sustained drought and system overdrafts,” he added. “I’m not interested, under those circumstances, in assigning blame.”