A new report from a group of widely respected Colorado River experts says the region's major reservoirs are sliding toward "devastating consequences" as water levels continue to drop.
The authors wrote that another dry year, on the heels of last winter's record-setting dry conditions, would send the nation's largest reservoirs to "run-of-the-river" levels, meaning that they would be unable to store water for the future and simply pass water downstream.
As a result, the paper's authors — a group of academics and retired water officials — are calling on state water managers and the federal government to work quickly on new rules for sharing the Colorado River and avert infrastructure problems at Lake Powell and Lake Mead, the nation's two largest reservoirs.
"This is an imminent possibility that we could lose the benefit of these very expensively constructed reservoirs," said Anne Castle, one of the paper's authors, "And the only way to prevent that from happening is to have significant reductions in consumptive use right now."
Even a very wet winter, Castle wrote, would provide only about two years of cushion before conditions returned to today's on-the-brink low levels.
A recently announced plan to prop up Lake Powell has the federal government sending water downstream from a reservoir in Utah and Wyoming. It's designed to stave off infrastructure problems at northern Arizona's Glen Canyon Dam in the short term.
Castle said that kind of creative accounting will not work in the long term.
"In order to stabilize the system, we don't have the luxury anymore of propping up the gap between supply and demand with stored water," she said. "We have to be able to cut sufficiently to offset that current gap between supply and demand."
The paper points out that federal data on reservoir levels typically focus on the total amount of water stored, a fact that obscures the reality of how those reservoirs work.
The federal government keeps a minimum amount of water in Lake Mead and Lake Powell to make sure there's enough to run through hydroelectric turbines inside the dams that hold them back. The amount of water available for cities, farms and tribes to use is the amount that sits on top of that minimum.
"We can be lulled into complacency if we just focus on what's called the active storage in the system," Castle said, "Because not all of that water is available for us to use, so one important goal of this paper is to provide a more realistic analysis of how much water is available to us."
Focusing on the amount above the minimum threshold should add some urgency to ongoing negotiations about sharing water in the future, the report said.
Those talks are largely at an impasse, and the seven states that use the river appear unlikely to reach an agreement about how to divide water amongst themselves.
A proposal from Arizona, California, and Nevada offered some major cutbacks to water use in those states, and will likely help inform the next set of federal rules for managing the Colorado River.
Nearly 40 million people use the Colorado River between Wyoming and San Diego. Castle said more of them need to call for action from policymakers.
"We need the normal people who turn on their taps and take showers and flush toilets and irrigate crops," she said. "Those are the folks who will be affected by a system crash, and all of us need to let our leadership know that we understand that we're going to have to use less water, and we want that to happen, so that the whole system stays afloat."
This story was produced by the Mountain West News Bureau, a collaboration between Boise State Public Radio, Wyoming Public Media, Nevada Public Radio, KUNR in Nevada, KUNC in Northern Colorado, KANW in New Mexico, Colorado Public Radio and KJZZ in Arizona as well as NPR, with support from affiliate newsrooms across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting and Eric and Wendy Schmidt.
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