The U.S. Interior Department released its final review of a long-awaited plan to deal with water shortages on the drought-stricken Colorado River. It leans heavily on reducing deliveries to Arizona, Nevada and California and, as written, would hit Arizona the hardest.
The new plan replaces guidelines that the Bureau of Reclamation adopted in 2007, and which have imposed shortage reductions on Arizona water users without arresting the decline in water storage in Lake Mead and Lake Powell, which sit at near-record lows. Those rules expire this fall.
Still 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, and will accompany a formal Record of Decision, the federal government's final step in approving projects with major environmental consequences.
Federal officials selected one of five alternatives in the draft environmental review, options that ranged from no action to across-the board cuts. State officials are already warning that Arizona can't accept the deepest cuts outlined in the framework.
Here's what to know about the drought plan, its effects on Arizona and what happens next:
The U.S. Interior Department's Bureau of Reclamation released its 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.
The federal government years ago signaled the need for deeper reductions to arrest the loss of water stored in the reservoirs, the nation's largest pair of dam-created reservoirs and the source of at least part of the drinking water supply for millions of Americans.
Those reservoirs started the 21st century essentially brimming with multiple years' worth of river flows, but now sit at just 27% and 23% percent of capacity respectively, and collectively hold only about what has flowed down the river in an average year during a megadrought that is nearing its third decade.
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 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.
The document released July 31 is a broad framework for the river's operations, but doesn't include specific cuts for each state. Those numbers will likely be included in a two-year operating plan that could be released in early August.
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.
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.
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.
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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, and will accompany a formal Record of Decision, the federal government's final step in approving projects with major environmental consequences.
Arizona's initial reaction to the federal plan was mixed, reflecting the dual possibilities that the new shortage guidelines could yet "devastate" the state but that their application could instead reflect the Lower Basin's "common sense" proposal.
The idea of a 3 million acre-foot reduction to the Lower Basin is "unacceptable," the Arizona Department of Water Resources said in a statement. "Such reductions would devastate Arizona's water users and its economy."
randon Loomis covers environmental and climate issues for The Arizona Republic and azcentral.com. Reach him at [email protected].
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: Colorado River plan could be 'devastating' for Arizona. What it means