Gov. Doug Ducey’s administration wants legislative authority to allow water users to skip delivery of some of their allocation this year to prevent shortages in future years. Such legislation would ensure that, if they leave the water in the reservoir, they can retrieve it later if river conditions improve.
The Central Arizona Project — whose canal delivers the water to Phoenix and Tucson — has opposed the idea, preferring to stick with existing programs. The agency has made the argument that holding small amounts of water in Lake Mead as the state proposes could backfire and bring shortages sooner.
So far, lawmakers have not introduced the legislation Ducey would need to make the idea work.
A shortage on the horizon?
The latest federal forecast predicts only about half the normal water will flow into the Colorado River system because snow has failed to pile up in the Rocky Mountains. If water users take their full allocations, reservoir storage will shrink faster.
“We need to act,” said Hunter Moore, the governor’s natural resource policy adviser.
The administration wants authorization to let users who are willing, such as some of the tribes controlling nearly half of the water flowing through CAP’s canal, to leave a portion of their water behind Hoover Dam. There, it could prop up Lake Mead’s elevation and slow a decline that otherwise could cause federal officials to reduce Arizona’s river diversion.
Such a shortage, which Arizona years ago agreed to take if the reservoir falls below 1,075 feet above sea level, would mainly affect central Arizona farmers.
But state officials fear a mandated reduction in water flowing toward Phoenix would look bad to outsiders, who could question whether the state has water for growth and business, and that further declines in Lake Mead would trigger more draconian cuts.
Banking water in the reservoir for later use, as the Arizona Department of Water Resources proposes, could prevent the shortages, officials said.
Finding the right balance
CAP officials argue that conserving too much too quickly could rob Arizona of water and force it to raise rates on millions of Arizonans to pay the canal’s bills even as the CAP sells less water through it.
The crux of the dispute is a set of federal guidelines by which the U.S. Interior Department tries to balance Lake Mead’s elevation with that of Lake Powell, the reservoir farther upstream.
In normal years the government releases at least 8.23 million acre-feet from Lake Powell to flow into Lake Mead, each acre-foot equaling the needs of about two households. That water essentially covers all of the approved uses in Arizona, California, Nevada and Mexico.
When Lake Mead shrinks, the government can send more downstream to keep levels up. In recent years, that has meant 9 million acre-feet flowing toward those users. It’s a flow that could dry up if Arizona’s conservation measures push Lake Mead’s elevation too high.
The risk to Arizonans is that they could conserve enough to elevate the lake and reduce the extra water from Powell, but not enough to prevent bad winters from triggering a shortage in two or three years anyway, CAP General Manager Ted Cooke said.
That would mean an immediate loss of the water that otherwise could have flowed through the canal and helped pay its bills in the interim.
“There will be a shortage unless the drought miraculously ends,” Cooke told a group of reporters visiting his headquarters on an Institute for Journalism & Natural Resources fellowship last week.
Cooke said CAP and others are already collaborating on funding farm efficiency and other measures to shore up Lake Mead. He advocates boosting those programs instead of stashing tribal water.
Do too little, lose a lot?
The Ducey administration acknowledges that raising Lake Mead too much could lead to short-term losses, but insists that doing too little could lead to more calamitous losses later on.
For instance, letting Lake Mead slide another 50 feet lower would cause Interior to shut off nearly a third of CAP’s water, severely affecting Phoenix and Tucson. It could happen if conservation volumes remain flat and winter snows keep underperforming.
The city of Phoenix has supported the state’s plan to push more conservation, even if reducing canal deliveries cuts into the water the city has taken and stored in the ground in recent years.
“Phoenix is willing to make those tradeoffs,” said Kathryn Sorensen, director of Phoenix Water Services. “We take a very long-term view of the river.”
The state needs to get the tribes to store water in Lake Mead before too many more dry winters make it too late, Arizona Water Resources Director Tom Buschatzke said.
“The tribes are not going to do it,” he said, “if CAP is the one that holds it in their names and dribbles it out as they see fit.”
CAP’s position is that its elected board has done well to conserve the right amount without causing federal managers to slow the flow into Lake Mead. The agency can increase those efforts without cutting back on canal flows that will hurt ratepayers, Cooke said.
The state wants more.
“A plan to let nature replenish the system is not a plan, right?” Buschatzke said.