Where did all the water go?
The Colorado River is drying up fast, which could spell serious trouble for the 40 million people who depend on it.
Last month’s federal declaration of an emergency water shortage on the Colorado River barely caused a ripple. But it should have made big waves.
The once-mighty Colorado, which provides water for 40 million people across seven U.S. states as well as half of Denver’s water, is in serious trouble. Choked by chronic overuse, a 22-year drought and the effects of climate change, the river’s flow has declined by nearly 20% this century.
The first-ever emergency declaration, triggered by historically low water levels in the Colorado’s largest reservoir, Lake Mead, means that multiple states face a forced reduction of their water allocation. Under existing agreements, Arizona, Nevada and Mexico next year will see their shares of Colorado River water drop by 18%, 7% and 5%, respectively.
“This is a big deal but not unexpected,” said Tom Cech, co-director of Metropolitan State University of Denver’s One World One Water Center. “The Colorado’s flows have been steadily getting worse for years, and the last time Lake Mead was full was in 1983.”
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Seen through a historical lens, this disaster has been a century in the making. Cech said that’s because the original multistate agreement outlining various states’ rights to Colorado River water use, signed in 1922, was hopelessly optimistic. It badly overestimated the total amount of water flow, with the result that the West has been living beyond its means ever since.
Add to this already-flawed formula the impact of climate change; extensive and often inefficient irrigation practices within urban and agricultural settings; and massive population growth, and Cech said it becomes easy to see how things have gone so wrong.
The numbers are sobering. The Colorado River supports 15 million more people today than it did just 29 years ago. And the fast-warming climate means up to 10% of the water in America’s vast Western reservoirs simply evaporates off of their surfaces each year.
According to the U.S. Bureau of Reclamation, Lake Mead is just 35% full.
Reversing the course
Cech said that while the federal designation won’t directly affect Denver and Colorado in the near term, the state should get ready for more rigorous outdoor watering management policies and restrictions in the future.
“Given our semi-arid climate, we simply use too much water for lawn and landscape irrigation,” he said.
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The question of how to slow or even reverse dramatic water losses is a hot topic in statehouses, especially since the decline has happened faster than expected. Some states have already taken proactive measures.
Over the past two decades, Nevada has implemented stout conservation efforts such as watering restrictions, removal of decorative grass and paying residents to replace lawns. These actions have reduced Southern Nevada’s Colorado River water usage by 23% since 2002, even as the population increased by nearly 800,000 residents.
Closer to home, Cech suggested checking out the water management programs of agencies such as Denver Water and Aurora Water, which for years have led the way in reducing per-capita water use.
“There are a number of concrete actions both cities and individuals can take,” he said. “For example, using native xeriscape plants, reducing lawn sizes, installing better irrigation systems and improving soil management.
“All of these measures will help reduce urban water use.”
Our shared future
While domestic conservation can help, approximately 70% of Colorado River water goes to sustaining crops, rather than serving the direct water needs of people in urban areas.
“The most effective programs will ultimately focus heavily on reducing outdoor irrigation,” Cech said.
And that’s the tricky part. So far, individual states have had to make only minor compromises, but a continued water shortage over the next few years could necessitate some deeply painful and unpopular decisions, Cech said.
Should the West’s shrinking reservoirs, for example, start to approach “dead pool” status (meaning they can no longer generate electricity), legislators would have no choice but to implement disruptive policy changes and large-scale water reductions. That would impact thousands of livelihoods that rely on irrigation water and potentially transform the whole agricultural landscape.
Such a grim scenario, once unthinkable, is now firmly on the table, Cech said.
Ultimately, Cech emphasized that the only way out of this crisis will be to tackle its root causes by focusing on conservation, reducing planet-warming emissions and changing how we live and eat.