The Interior Department on Tuesday shared its proposal for expected cuts to Colorado River water allocations but acknowledged that the most extreme options — including a plan that would slash water deliveries to Arizona and Nevada — are unlikely to be included in a final decision this summer.
Instead, agency officials presented their emergency plan — which includes contrasting proposals that would either force California to forfeit a significant portion of its flows or concentrate the pain of cuts on Arizona and Nevada — as a set of “bookends” to motivate state officials to collaborate.
“I would not think about either of these three alternatives as something we’re asking people to choose, but rather, they’re models and alternatives and ways of defining the problem,” said Deputy Interior Secretary Tommy Beaudreau, referring to an update of the 2007 Colorado River Interim Guidelines.
Interior is in the process of overhauling those rules, which dictate how much water is withdrawn from Lake Powell and Lake Mead based on their current surface elevations, in a bid to save hydropower production on the river by raising water levels in the reservoirs, which have dropped precipitously in recent years.
The plan is also a safeguard against those reservoirs’ dropping to “dead pool” status, when water levels are so low that flows cannot escape from behind the Hoover or Glen Canyon dams, and cannot flow to the Lower Basin states of Arizona, California and Nevada.
The draft report released Tuesday includes three options, although Bureau of Reclamation Commissioner Camille Calimlim Touton dismissed the so-called no-action alternative — in which the river is managed without any significant changes — as “the worst alternative,” as it would put water supplies at risk for the 40 million individuals who rely on the river.
Another option calls for instituting pro rata reductions across the three Lower Basin states — which the agency said reflects a plan proposed by six of the Colorado River states, with the exception of California — sharing the pain of future shortages proportionally.
The third alternative would shield California from much of the initial pain of any cuts, by relying on priority water rights to decide where to halt flows first.
In the West, water rights are a property right, with older or more senior claims receiving priority for water in years when river flows are lower, while more junior claims may be required to forgo some or all of their water.
Arizona’s largest water delivery agency, the Central Arizona Project, or CAP, was designated with junior status under a 1968 law. California, on the other hand, claims both the most senior and the largest share of the Colorado River, at 4.4 million acre-feet.
But Beaudreau acknowledged that relying on “straight, unmitigated priority” is unlikely to be the agency’s final decision.
“That said, it’s important for everyone to see what that would look like. At the other end of the spectrum, you have pro rata shares: just taking look based on consumptive use, a mathematical formula to divide how much water you need to save in the system on a straight line basis across water users. That is also a very rough way to manage those shortages,” he said.
Beaudreau added that the draft plan is intended to motivate states, which have failed to produce a basinwide plan, to continue to collaborate.
He said: “That is the process we wanted to set in motion, and we’re very much looking forward to that dialogue.”
The plans — which are in draft form and under review for 45 days, with a May 30 deadline — aim to cut use of the river by a maximum of 2.083 million acre-feet by 2026. That amount of water could provide 6.2 million families with water for one year.
Lake Mead currently sits at an elevation of 1,046 feet, and is filled to about 28 percent of its capacity, according to Reclamation data.
Under the priority status-based plan, California would not give up any additional water at the current elevation. At the same time, Arizona would be required to forfeit 1.025 million acre-feet of water and Nevada 42,000 acre-feet of its share of the river.
But under the plan in which the Lower Basin states would be subject to the same percentage cut — or 11.56 percent, at its current elevation — California would forgo an extra 509,000 acre-feet of water, while Arizona would forfeit 324,000 acre-feet of water. Nevada would need to give up an extra 35,000 acre-feet of water.
Those figures are in addition to previously negotiated cuts to Colorado River allocations.
“These are difficult issues decades in the making,” Beaudreau said. “And so, yes, some of the conversations can be difficult, as well. The reason I’m hopeful that new agreements and solutions will continue to emerge, though, is that the spirit in the basin is one of community and collaboration.”
Correction: This story was updated after publication to correct a quote attributed to the wrong person. Interior Secretary Tommy Beaudreau said the statement that begins, “These are difficult issues decades in the making.”