Lake Mead was about 40% full in December 2019, but will almost certainly fall further this year, as will its companion reservoir of the desert southwest, Lake Powell. Photo/Allen Best
We need a word that better captures what’s happening in the Colorado River Basin
by Allen Best
In New Mexico last week, a couple in Santa Fe was weighing whether to build a house on the 20-acre lot they had purchased. Among the questions perplexing them was how the warming and drying climate might marginalize their asset.
Relatively few people were asking such questions a decade ago. Now they are. Most people remain more concerned about making the next mortgage payment or a dozen other concerns, but climate change has ceased to be a future worry. It’s right outside the door, evident in the rising heat, the larger and more frequent wildfires, and the news of broader and exceptional “drought.”
One aspect of the warming that has been widely if mostly anecdotally observed has been the melting of snow in winter months. Less snow has been making it to spring—and that means less water flowing in rivers come summer.
“New paper out on widespread increased snow melt during the winter in the US West by well-known scientists,” tweeted Brad Udall, who is himself something of a well-known climate and water scientist affiliated with Colorado State University.
“These papers never have good news, alas. Meanwhile #coloradoriver runoff currently forecast at 45% despite 80% snowpack.”
In the paper, “Winter melt trends portend widespread declines in snow water resources,” four researchers—three from Colorado—compared records of 1,065 snow-measurement stations in the West between the Mexico border and continuing northward into the Alaskan Arctic since the 1970s.
Melting before April 1 has increased at almost half of the stations by an average 3.5% per decade.
This so-called winter melting has been most prominent in November and March, although it has occurred in all months, they say in the paper published in Nature Climate Change.
“Historically, water managers use the date of April 1 to distinguish between winter and spring, but this distinction is becoming increasingly blurred as melt increases during the winter,” said Noah Molotch, a study co-author and associate professor of geography and fellow at INSTAAR.
The mountains have often been described as the water tower of the West, akin to the tanks that stand over many small communities. The snow melts rapidly during spring, of course, but then slowly melts well into summer. Now, there’s less snow to melt. The tank on the hill has less water.
“That slow trickle of meltwater that reliably occurs over the dry season is something that we have built our entire water infrastructure on in the West,” Keith Musselman, of the Institute of Arctic and Alpine Research, told CU Boulder Today, an arm of the University of Colorado.
This causes my mind to wander to the Colorado mountain town of Red Cliff, a place of roughly 300 people located at an elevation of 8,600 feet not far from the Continental Divide. One of the life-time residents there, a “powder man” in several of the local mines, observed that the snowpack normally grew until St. Patrick’s Day, then began to shrink. The snow depth could rise again with new snow, but only temporarily. With warming winters, I wonder when the snowpack at Red Cliff now ceases to rise. Might it now be early March?
This is from the April 18, 2021, issue of Big Pivots. For a free subscription, go to BigPivots.com
Authors of the new study point out that this shift in melting could affect wildfire season and agriculture irrigation needs. They also note that their findings are consistent with what climate models suggest will continue to happen.
One feature of this incremental warming has been early runoff, with peaks roughly two weeks earlier in this century.
In Steamboat Springs, the Pilot reported on April 7 that the snow-water equivalent going into April stood at 14.5 inches, according to the Natural Resources Conservation Service. If that stays as the peak, the 2020-21 winter will have peaked seven days earlier and with about 3.4 inches less water than the 30-year median peak. “The thawing has begun earlier than we would like,” said Kelly Romero-Heaney, the water resource manager for the city of Steamboat Springs.
Maybe it will snow in May—a lot. I remember the spring of 1983 when I was working in Winter Park. A a so-so ski season was followed by an exceptional spring. We barely saw the sun. It seemed to snow every day. And then when the snow melted, the gush took water managers downstream at Glen Canyon Dam by surprise, almost toppling that massive plug that creates the playground of Lake Powell.
Now Powell and its companion behemoth in the desert Southwest, Lake Mead, have struggled in the 21st century. The two reservoirs, largest in America, have a capacity for 54.5 million acre-feet. They’re not close to half full—and they’re likely to decline more this year. Too many years have been like 2020.
Nearly all the water flowing in the Colorado River originates in the headwater states, most of all Colorado, and mostly as snow. In 2020, the snowpack in the upper basin was 114% of average. That snowpack yielded only 55% of average runoff.
Let’s wrap our minds around those numbers again: snowpack 114% of average and runoff 55% of average. Wow.
This year, the snowpack is nowhere near as good. “Current conditions resemble 2002, 2012, and 2013 and the beginning of 2018, four of the five driest years on record,” said the Bureau of Reclamation in an April 15 report. As Udall noted in his tweet, the Bureau projects flows 45% of average into Powell.
As KUNC and other news outlets have reported, this marginal runoff will almost certainly mean that water levels in Lake Mead, the reservoir outside Las Vegas, will drop below the critical threshold of 1,075 feet. As per an agreement among the seven states in the Colorado River Basin in 2019 and also Mexico, this means there will be further cuts in deliveries to Arizona, Nevada, and Mexico. California could also see its river allocation restricted if the declines continue.
Have Colorado and other states in the Southwest come to terms with the new reality? Yes—and no. A bit of history is worth visiting.
Eric Kuhn and John Fleck, in “Science Be Dammed: How Ignoring Inconvenient Science Drained the Colorado River,” demonstrated how willfully those who created the framework of compacts and water-delivery infrastructure in the Colorado River ignored available evidence that the river might not well deliver the quantities they wanted to assume. They assumed upwards of 20 million acre-feet. In fact, in the 21st century, the river has been delivering an average 12.5 million.
The science that framers of the Colorado River Compact ignored when they gathered in Santa Fe in 1922 was that of substantial periods of lesser flows in the 19th century. Congress had better evidence yet—but again ignored it when approving the compact in 1929.
Further scientific research has yielded confirmation of decades-long periods of low flows, the megadroughts of a thousand years ago.
Not until the 1960s was there a grudging appreciation for limits. And not until 2007 was there more explicit acknowledgment of the need for revised assumptions.
We’re now in the midst of that acknowledgement. In the 2019 agreement among the basin states, commonly called the “Drought Contingency Plan,” Arizona took the biggest cut, but California got creative, too. That agreement might just as easily have been called the “Buying Time Agreement,” because that is essentially what it did, providing interim measures while a greater vision was assembled to be implemented in 2026. Work is just now beginning on that next iteration.
In 2019, when I interviewed Udall, he said he objected to the word “drought” in the title of the plan. It suggests a temporary condition. He and others have been producing evidence that roughly half the runoff decline has been the result of warming caused by accumulated greenhouse gases. The higher temperatures result in increased evaporation, sublimation, and transpiration. Other researchers have reached much the same conclusion. In a 2019 paper, Udall and Jonathan Overpeck chose to call it a “hot drought.”
Others in the Colorado River Basin have similarly been parsing their vocabulary.
“The drying trend” is the new abnormal—it is not a drought,” Kuhn tweeted this morning.
James Eklund points to increasing temperatures of 1.5° F globally since his great-grandparents began ranching in western Colorado in 1888. Eklund, a former director of the Colorado Water Conservation Board, among other postings, uses the phrase “aridification,” the gradual change of a region from a wetter to a drier climate.
He also coined a word, “spongeification,” in a 5,000-word essay published in the April 15 issue of The Water Report. By this, he means the process by which dry soils and depleted groundwater aquifers soak up the runoff that does materialize.
Eklund, in an e-mail, told me that he intentionally used the word drought sparingly “because we’re not in a drought (which implies that we might rebound next year).”
It had snowed hard in metro Denver the day he wrote me, and he made note of that snow (which wasn’t nearly so heavy in the Colorado River Basin).
“Despite the snow out the window (and thank heavens for it!), the water year in Colorado and in the Colorado River Basin is going to be challenging at best and perhaps seriously disruptive,” he wrote. “Despite all the coverage and hyperbole, I do not see the current water apparatus (of which I consider myself a part) moving quickly enough to confront the challenge climate change presents to our water systems.
Eklund’s essay makes the case for stepped up implementation of demand management, as I understand it, a way for ranchers and farmers in places like Colorado to lease their water. Whatever the techniques, there must be responses sufficient to the shifting climate.
Then there is conservation. The Las Vegas Sun this week lent its cautious support for a bill in the Nevada Legislature that proposes to make removal of ornamental grass mandatory – not voluntary, a response to incentives, as has already resulted in the uprooting of more than 200 million square feet of grass lawns. If the only time we set foot on grass is to mow it, what real purpose does it serve?
I see a greater role for landscape architects in our future. Dumping gravel on a yard, one of the common solutions to water scarcity that I have seen in Las Vegas and Santa Fe – and, actually, in my own relatively verdant neighborhood in suburban Denver—just doesn’t cut it.
But back to drought, a word that falls short, at least given our current meaning of it. I think we need a better word or phrase that conveys what happens better than “drought.”
Once we can come up with a better word or phrase, we’ll more readily get to work on adaptations necessary with this shifting climate that will change and then change and change again. BP
Brad Udall and Jonathan Overpeck on “Climate change and the aridification of North America.”
Assistant Colorado climatologist Becky Bolinger assigns grades to the Colorado River Basin’s snowpack in Washington Post.