The big slide on the Colorado River likely far from over

by Allen Best

Big Pivots

Flows in the Colorado River have declined 20% in this century. Is that the new normal?

Don’t count on it, say John Fleck and Brad Udall as the seven basin states gather their thoughts about how to craft agreements going forward that reflect the shifting hydrology in the river basin.

Writing in the May 28 issue of Science, Fleck and Udall point out that it is “tempting to use today’s 20% flow decline as the new baseline—that is, modeling future reductions on the basis of what has already been observed. But only by planning for even greater declines can we manage the real economic, social, and environmental risks of running low on a critical resource upon which 40 million North Americans depend.”

Fleck, a former newspaper reporter for the Albuquerque Journal, is a professor in the Water Resources Program at the University of New Mexico. He has written several books, most recently co-authoring “Science Be Dammed” with Eric Kuhn, the former general manager of the Colorado River Water Conservation District.

This was published in Big Pivots 39 on June 8, 2021.

In that 2019 book, they documented the flawed assumptions and what might be called an irrational exuberance in the making of the Colorado River Compact. Delegates to the meeting in Santa Fe in 1922 had disturbing evidence of lesser flows than were assumed by the agreement they crafted and Congress had even more evidence when it ratified the compact in 1929.

Udall, of the Colorado Water Center at Colorado State University, has been among several researchers in recent years to offer compelling evidence that what is still being called drought in the Colorado River Basin is only partly that. At least half of the reduced flows can be attributed to rising temperatures that result in less of what is called “runoff efficiency.” In other words, how much snow and rain actually ends up as water in the river—and water in the two big reservoirs, Mead and Powell.

“For every 1°C of warming, researchers expect another 9% decline in the Colorado’s flow,” Fleck and Udall wrote. “This year’s snowpack was 80% of average but is delivering less than 30% of average river flows. Hot, dry summers bake soils, reducing flows the following year.”

(Actually, it may be worse than that. The National Western Service at its Colorado River Basin site reported on June that the April-July inflow into Lake Powell was to be 23% of average, the third lowest in the 58 years of records).

The 21st century shift in water flows have forced a new reckoning, which the states have begun to address. California has cut back diversions to accord with its entitlement, but perhaps the most flagrant recognition is the cut in deliveries to Arizona’s Pinal County, an agriculture district between Phoenix and Tucson that has enjoyed flows from the Central Arizona Project. No more. Arizona had to make cuts, and these farms were lowest in priority for complicated reasons.

The 2019 drought contingency plan—it had a much longer, fancier name—just kicked the can down the road. The big decisions are comings are coming up in the next 2 or 3 years. That is what Fleck and Udall address in the editorial in Science.

“Computer simulations showing emptying reservoirs were enough to convince decision-makers of the need to cut back. But have the modelers gone far enough?” they ask.

But the science now—as in 1922—may be the less difficult challenge, they suggest.

“Climate science indicates that there will likely be less water in the Colorado River than many had hoped. This is inconvenient for 21st-century decision-makers, and overcoming their resistance may be the hardest challenge of all.”

This story was published in the June 8 issue of Big Pivots.

Ground ‘very thirsty’ in the Yampa River Basin

Credit Doug Monger for having the most engaging quote in describing the water situation in the headwaters of the Colorado River.

“We kind of knew this thing was coming mid-winter,” Monger told the Steamboat Pilot “It doesn’t take a rocket scientist to figure out you cannot dump enough water on this ground right now – it is just thirsty.”

Monger ranches near Hayden and sits on the board of directors for the Colorado River Water Conservation District.

This year may be second worst in this 21st century, behind only 2002 in terms of runoff. The snow-water equivalent in the mountains of the Yampa River Basin was 4.7 inches, compared to 2.3 inches of water on the same date in 2002, the Pilot report.

Two new policy advisors in Colorado agency in realm of water, climate, and energy

Dan Gibbs, the director of the Colorado Department of Natural Resources, has two new high-level policy advisors.

Kelly Romero-Heaney, the director of water resources at the City of Steamboat Springs, will join the state agency as assistant director of water policy. Her diverse experience—including a stint as a wildland firefighter—will inform her work in updating the Colorado Water Plan, overseeing interstate negotiations around the Colorado River, and implementing new water measurement rules.

Angela Boat, already a staff member, has been promoted to the position of assistant director for climate, forest health and energy. She has served in the role of a policy advisor for those topics for the last 18 months.

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