From my conversation last week with Drew Kann at CNN:
To Fleck, all of this signals that the reduced flows in recent years are likely not an aberration, but rather a glimpse of the challenges posed by a hotter, drier climate.“We’re now seeing the model for what the future of Colorado River Basin water use looks like, where scarcity is the norm and drought is not some special short-term thing,” he said. “This is the way of life we’re in now with climate change reducing the flow on the river.”
Boulder Harbor, Lake Mead, Oct. 18, 2010
I’m choosing my words carefully here. The “likely” in this blog’s post’s title means “based on my analysis of the Bureau of Reclamation’s current ‘most probable forecast’ Colorado River water supply model runs.”
The Bureau’s current “most probable” modeling suggests that in both 2022 and 2023, the annual release from Lake Powell will only be 7.48 million acre feet. This is based on a provision in the river’s operating rules that, under certain low storage level conditions, the Upper Basin gets to hang onto water in Powell.
The last time and only time we had a 7.48 release, in 2014, Mead dropped 25 feet in a single year. We’ve never had two consecutive 7.48 releases.
The headline in yesterday’s release of the Bureau of Reclamation’s “24-month study” (pdf here) is that Lake Mead will drop below elevation 1,075 at the start of 2022 (triggering a “Tier 1” shortage) and could drop below 1,050 by the start of 2023 (that’s the trigger for “Tier 2”).
Tier 1 next year, which primarily hits Arizona with some deep forced reductions, was no surprise. That’s been obvious for a while, and Arizona’s water leadership has been softening folks up for months. The increasing risk of Tier 2 in 2023, which would mean deeper cuts in Arizona, is sorta new, but it’s been foreseeable.
The real “holy shit” for me in yesterday’s release was the trail of breadcrumbs in the Bureau’s data, pointed out by my co-author Eric Kuhn, leading to a “most probable” Lake Mead drop to elevation 1,035 by the end of September 2023.
To be clear, the Bureau isn’t saying this yet. The latest 24-month study stops at the end of March 2023. But internally, the Bureau runs the model out farther in order to determine, among other things, how much water is likely to be released from Powell in 2023. And the published numbers clearly show – the Bureau’s “most likely” scenario would call for another 7.48 release.
From there, it’s just arithmetic. Based on my analysis of the publicly available numbers, the “most likely” scenario puts Mead at elevation ~1035 at the end of September 2023. This is my math, but my understanding is that it’s consistent with what the Bureau’s internal calculations show.
In my linguistic equivalence here between “likely” and “most probable forecast”, remember that I’m talking about the midpoint in a range of possible outcomes. A run of wet weather could make things substantially better.
But a run of dry weather could make them worse.
Cleaning out some old files this morning, I ran across this great quote from Pat Mulroy some years back from a talk about the problems of the Sacramento-San Joaquin Delta. Via’s Maven’s Notebook:
We are very, very good at saying no. We are very, very good at blocking. Anybody can stop anything. What we can’t do or can’t seem to do is find a structure within which to say yes. You will never have enough science, you will never have enough data, but at some point, something has to change.
This applies beyond the California Bay-Delta.
.@VP Kamala Harris: "For years and generations, wars have been fought over oil. In a short matter of time, they will be fought over water." pic.twitter.com/88pWzvbmeA
— The Hill (@thehill) April 7, 2021
Flow so low I needed to switch to log scale
I mostly hate log scale in graphs I use for broad communication purposes. It’s just not intuitive.
But I’ve made the switch for this year’s Rio Grande, because the flows are so low that we need the log scale, because at really low flows small changes become big, if that makes any sense. The difference between 50 and 150 cubic feet per second through Albuquerque is hugely consequential for the our river. Best to have a visual display that highlights that.
My friend and colleague Becky Bixby (UNM biologist, associate director of the UNM Water Resources Program) gave a great talk recently about her work on the diatoms – little light-eating algae – on the margins of our river. (first 10-ish minutes is Becky)
An email exchange with a friend who helps manage New Mexico’s water led to the graph above, my first stab at a visualization to try to show the accumulation of two bad years’ flow on the Rio Grande. Not quite sure this does all the work yet that I need of it, but perhaps worth sharing….
Total storage on New Mexico’s Upper Rio Grande reservoirs right now is the lowest it’s been at this point in the spring in over four decades of records
No sooner did my spring break begin a week ago (quite literally within a couple of hours of the end of my last class before break) than I got sick. This has led to much laying around, and resting, which I think was the point?
I’m finally on the mend, and a friend got me out of the house yesterday morning for a walk down by the river. Which was nice, except I have the sort of friends who have the latest Rio Grande gossip. Like about how we could see the river go dry by June, stuff like that.
Sigh.
Rio Grande at Albuquerque’s Central Avenue Bridge, March 19, 2021
To be honest, the river looks pretty good right now. There were a few buds to be seen, but mostly the river’s still wearing its winter colors, the quiet tans and browns that I’ve always thought were one of its best looks. With the gauge at the Central Avenue Bridge reading a bit less than 600 cubic feet per second, it was enough water to barely fill the channel from bank to bank, which as you can see from the picture also is a nice look. It’s only 25th percentile flow for this time of year, but not awful.
The awful is the thing we expect to come next.
The March 1 forecast called for 54 percent of the long term mean flow in the river into New Mexico’s “Middle Rio Grande Valley” – the part of the river where I live, the “Albuquerque reach”. That’s the mid-point, the one-in-ten best chance (90th percentile) is 93 percent of average, the one-in-ten worst (10th percentile) is 26 percent.
That’s bad, but the situation is made far worse by the graph at the top of the page. Mid-March total storage in the three upstream reservoirs was just 140,300 acre feet, which is just 29 percent of average and, more importantly, the worst in the dataset that I have access to, which goes back to 1980.
We’ve limped by in recent years by draining storage, keeping the river wet for the cultural and environmental benefits that provides, and keeping the irrigation ditches wet as well. That’s not going to be possible this year. That’s why my gossipy friend, who is connected, pointed to the possibility of river drying by June.
A note on data sources and methods: The data comes from the USBR Upper Colorado Region’s historical datasets, to be found here. I grabbed the data for Heron, Abiquiu, and El Vado reservoirs, summing up total storage for March 15 every year for which we had data on all three, which goes back to 1980. There’s probably longer datasets available somewhere, but I’m just an unpaid blogger with a few spare hours on a spring weekend, so you get what you pay for, eh?
The AP’s Sophia Eppolito did a nice job of pulling a single bit of business from a lengthy interview that captured the key point of my thoughts on Utah’s approach to Colorado River governance and water management:
The river supplies Arizona, California, Colorado, Nevada, New Mexico, Utah, Wyoming and Mexico as well as a $5 billion-a-year agricultural industry. As the states face a dire environmental future and negotiations over a new plan to protect the waterway from drought, it’s forced a shift in thinking.
The goal of renegotiating is figuring out how to use less, “not staking out political turf to try to figure out how to use more,” said John Fleck, director of University of New Mexico’s Water Resources Program.
“It’s just not clear Utah has a willingness to do that,” he said.
I’ll be joining Tim Quinn, former executive director of the Association of California Water Agencies; and Tracy Quinn, Director, California Urban Water Policy, Healthy People & Thriving Communities Program at the NRDC (and also a board of of the Metropolitan Water District of Southern California) in a webinar to talk about collaboration and conflict around water:
A week doesn’t go by without someone saying there are water wars underway or about to kick off in California. How we manage and govern water is critically important to people, the environment, and the economy. But, are we really at war? Really? Do we believe there are always victors and vanquished? What is the impact of telling ourselves and others this is warfare, when in reality it is simply the messiness of working together in community?
So, we’ve gathered a panel to answer the question: Water wars, what are they good for?
Chris Austin (California’s Water Maven), along with the super interesting Mike Antos, a social scientist smart in the ways of water collaboration, plus the always fascinating Lisa Beutler. (Mike and Lisa are with Stantec.)
After a super interesting brainstorming call this afternoon with the five of them, I’m really excited about the conversation. This’ll be fun, please join us, sign up here.