Federal officials released a plan on July 31 for dealing with Colorado River water shortages that will lean heavily on curtailing deliveries from Lake Mead to downstream users including Arizonans.
The plan allows for cuts of up to 3 million acre-feet a year among the states in the river’s Lower Basin — Arizona, California and Nevada. That’s nearly twice what those states have offered to conserve. Arizona officials have said such a blow would be devastating, possibly cutting off the Central Arizona Project’s deliveries to Phoenix and Tucson. But they say that level of reduction is not likely at least in the initial two years.
The U.S. Interior Department’s Bureau of Reclamation released it long-awaited environmental study that will underpin a new
plan for keeping Lake Mead and Lake Powell from dropping to critically low levels. It provides a framework the agency intends to adapt to current climate and hydrological conditions every two years.
Yet to come is a detailed description of what reductions the states will face in the first two years. That document’s release is expected in coming days or weeks.
The new plan replaces guidelines that Reclamation adopted in 2007, and which have imposed shortage reductions on Arizona water users without arresting the decline in water storage. Those rules expire this fall.
Plan offers 'flexibility' to respond to changing conditions
Arizona officials expect that for at least the first two years the federal government will enforce rules that they and counterparts in California and Nevada proposed. The states offered to save 3.2 million acre-feet over two years, including 1.25 million a year in mandatory, uncompensated cuts and 700,000 in voluntary conservation, some of which would use federal payments as incentive. Each acre-foot contains about 326,000 gallons and is enough to sustain about three households for a year, though the majority of Colorado River water is applied on farms.
“The Department has a responsibility to ensure the Colorado River system remains reliable and resilient for the millions of Americans, communities and industries that depend on it,"Interior Doug Burgum said in a statement accompanying the plan’s release. "This framework provides the flexibility to respond to changing hydrologic conditions while preserving the opportunity for the Basin States to continue working toward durable, consensus-based solutions.”
Arizona stands to lose the most, in part because congressional approval of the Central Arizona Project Canal delivering water to Phoenix and Tucson required the state to accept a junior right compared to California’s. That’s already been reflected in the canal’s reductions of hundreds of thousands of acre-feet a year over the last several years, and the new plan also calls on Arizona to give the most.
If Interior accepts the Lower Basin proposal for 2027-2028, the state is expected to forego 760,000 acre-feet a year in mandatory cuts out of its 2.8 million acre-foot allocation. California is expected to give up 440,000 of its 4.4 million acre-feet. Nevada’s share was only 300,000 acre-feet to begin with, so its volume of reductions is much smaller.
The 10-year framework makes 3 million acre-feet the maximum reductions that the Lower Basin could face, and only in harsh drought years when reservoir levels threaten to dip to where the dams cannot make electricity or reliably release water to the river. Where the Lower Basin routinely counted on receiving 7.5 million acre-feet in the past, mostly from releases from Lake Powell to fill Lake Mead, this plan allows for Powell to release as little as 5 million acre-feet in a year when its dam at Glen Canyon needs to retain water to function.
Such cuts would occur using the existing legal priority system, meaning junior priorities such as the Central Arizona Project could be completely cut off in a worst-case scenario. State officials speaking on background said federal decision makers wanted to include a wide range of options for dealing with future calamity, but that any attempt to actually cut off CAP and the millions of people it supplies around Phoenix and Tucson would first require more analysis and negotiation.
Still long-term issues to solve
As frightening as the worst-case may be, if the first two-year cycles sees only 1.25 million acre-feet in mandatory reductions per year, it will represent a win of sorts for the Lower Basin, or perhaps as good as they could have hoped for. Ideally the three states had hoped to convince the Upper Basin to accept its own mandatory reductions, or to have Interior impose them, but the department has less clear authority to do so in that region.
A 20th century Supreme Court edict gave the department’s secretary power to operate as “water master” in the Lower Basin, essentially to resolve disputes between Arizona and California. The four upstream states – Colorado, New Mexico, Utah and Wyoming – effectively split their allocations through appointees on an Upper Colorado Basin Commission. Those states have so far resisted mandatory cuts because they already use less water from the river and routinely cut off irrigators when headwaters streams are projected to go dry.
That dispute remains under discussion among the states, and could still become grounds for a lawsuit among them. Although Interior does not have explicit authority to impose cuts on the Upper Basin, the compact does contain a provision guaranteeing that those states won’t cause the flows to decline below what’s needed to provide the Lower Basin its share – a provision that may be triggered for the first time this year. It’s a potential cause for legal option that Arizona has noted in hiring outside legal counsel to prepare for a challenge, though one that the state has also said it could look beyond if the seven states can negotiate a suitable compromise.
Arizona has also made clear that in dry years when the Lower Basin’s cuts aren’t sufficient, it expects consultations with federal managers and the Upper Basin states that would lead to emergency releases from Upper Basin reservoirs, chief among them Flaming Gorge near the Utah-Wyoming boundary on the Green River. Reclamation has tapped that reservoir in previous dry years to prop up Lake Powell, and is doing so again this summer for up to 1 million acre-feet.
While not committing to mandatory cuts, the Upper Basin is working with Reclamation to create a voluntary conservation program that would use $100 million in federal funds to incentivize users to leave water in the river. For that amount of money, officials expect to save roughly 100,000 acre-feet over two years.
Reclamation’s new guidelines call for up to 200,000 acre-feet in Upper Basin conservation per year, but on a voluntary basis and “subject to hydrology.”
“This plan strikes a balance between flexibility and predictability for the Colorado River system that is vital to the 40 million people who rely on it given unprecedented hydrologic conditions and the potential for considerable impacts on water users,”Assistant Secretary for Water and Science Andrea Travnicek said in a written statement. “It also allows a new flexibility to respond to changing conditions and potential consensus.”
Brandon Loomis covers environmental and climate issues for The Arizona Republic and azcentral.com. Reach him at brandon.loomis@arizonarepublic.com.
Environmental coverage on azcentral.com and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust.
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This article originally appeared on Arizona Republic: Arizona would lose the most in proposed Colorado River drought plan
