Continue reading ‘Making sense of the crazy outlier year of 2026’ »]]>

Driest Rio Grande flow on record

Updating my “drought and climate change” lecture each fall is a useful exercise – this year more useful than most. Much like the year itself, my slide deck is setting all time records for new data visualizations needed to make sense of the remarkable 2026.

Update

Great questions from the comments. (I love my commenters.) First, a request to include a smoother to make the trend more legible:

Now with bonus smoother.

Second, an observation that it looks like it tracks the Pacific Decadal Oscillation, a large scale pattern linked to drier conditions in the southwest. Good eye! A quick run of the numbers based on prior-year fall PDO shows a statistically significant but small (r squared explaining 6 – 9 percent of the variance) relationship.

Worth noting that this is all of the water flowing past Otowi, which is a function of climate and all the many human activities upstream (irrigation reducing flow, San Juan-Chama adding to flow). So it’s not solely a climate signal.

Weirdly, when I redid the analysis for the Del Norte gage, which is above the San Luis Valley diversions and should be a clearer climate-alone signal, the relationship disappears. No correlation at all with PDO, which surprised me.

Continue reading ‘Quoting Aristotle’ »]]> Aristotle on the wisdom of Colorado River Compact litigation:

Now, it is of great moment that well-drawn laws should themselves define all the points they possibly can and leave as few as may be to the decision of the judges…. [L]aws are made after long consideration, whereas decisions in the courts are given at short notice, which makes it hard for those who try the case to satisfy the claims of justice and expediency.

Aristotle, Rhetoric

Continue reading ‘A river returns’ »]]> My office mate and podcast hosting buddy Rin Tara had the good sense to pull out their phone and record some stuff while we were out at the Rio Grande Thursday, beneath the I40 bridge, waiting for the pulse flow to arrive. We had the good fortune to bump into Audubon’s Tucker Davidson when we were out there, who helped explain the role of a river as habitat, and we got to see the water arrive. We hope you enjoy the results as much as we enjoyed making this week’s episode of Water Matters. (I can’t emphasize enough how much fun we’re having with this podcast thing. Huge props to Francesca Glaspell who handles the behind-the-scenes magic, and the Utton Center for giving our podcast project and all the work we do a home.)

Continue reading ‘Visualizing the 2026 Albuquerque pulse flow’ »]]>

Visualizing the pulse flow (click on the image to embiggen).

Hitting “reload” and keeping track of six open browser tabs was making my head hurt – this helped.

Back story here via Paul Tashjian, written as the pulse flow was getting underway:

As I write, action is underfoot to combine water from the Albuquerque-Bernalillo County Water Utility Authority, the Middle Rio Grande Conservancy District and Audubon for a release of water into our parched Rio Grande. The hope is to water the riverbed for four days through Albuquerque, soak the aquifer, and provide an “irrigation” to our stressed and dying bosque forest. At the same time, a robust monitoring program has been put in place to understand groundwater response, the seepage rate, characteristics of the watering, and the response of the trees themselves. This monitoring effort will provide invaluable insights to water managers about how we may solve problems of this nature in the future.

Continue reading ‘Wooden bats’ »]]>

Wooden bats.

Turned into the Mount Calvary Cemetery heading home from my Sunday bike ride, stopped in the shade to cool off before heading up the hill, home. From across the street in Santa Barbara Park, I could hear the sound of a ballgame, chatter in a language that I understood even if it was not my own.

When I got back on the bike, I rolled over to check out the game.

They had serious uniforms, were playing with a smiling rhythm that was friendly, the chatter was friendly. As I sat for a minute, the only person in the stands, a guy walking around behind home plate to get some bottles of water from the opposing dugout asked me if I wanted to play.

The bats were made of wood.

Continue reading ‘A deep dive into the data on Lower Colorado River water use’ »]]> Great new stuff from the Colorado River Wilburys – Jack Schmidt, Anne Castle, Eric Kuhn, Kathryn Sorensen, and Rin Tara*:

Reductions in Lower Basin water use during the last four years, including forecast use in 2026, are similar to the initial targets for Lower Basin shortages described in the Final Environmental Impact Statement for Post-2026 Operational Guidelines and Strategies for Lake Powell and Lake Mead (FEIS) and the accompanying Record of Decision (ROD).6 Lower Basin consumptive use in 2023, 2024, and 2025, and forecast for 2026 has been the smallest for the entire 2010-2026 period. These four years of smallest use are between 1.4 and 1.7 million acre feet/year (maf/yr) less than the 7.50 maf/yr amount
generally recognized as the Lower Basin’s mainstem allocation.

Reductions in Lower Basin use have been achieved by large reductions implemented by Central Arizona Project (CAP) contractors and subcontractors, the Imperial Irrigation District (IID), and non-CAP water users in Arizona. The reductions in use in the IID have been in summer water use and have not affected consumptive use in winter when garden crops, such as lettuce, onions, carrots, and broccoli, are grown.

The full paper: The Colorado River Water Supply Crisis in a Few Graphs: Part 2 Agricultural Water Use in the Lower Basin

* (I’m still on Colorado River sabbatical, so not an active contributor to the latest Wilburys projects, but they still let me wear the hat.)

Continue reading ‘Chasing the water’ »]]>

“Game on!” as a friend texted yesterday afternoon.

At 2 p.m. Monday (Aug 31, 2026) the Albuquerque Bernalillo County Water Utility Authority, along with the Middle Rio Grande Conservancy District and Audubon Southwest, began releasing a pulse of water from Abiquiu Reservoir on the Rio Chama in Northern New Mexico as an experiment – what might a several day pulse of water do to help the aridification-starved riverside forests along New Mexico’s Middle Rio Grande?

Here’s Bernalillo County Commissioner Barbara Baca, chair of the ABCWUA board:

This one-time release will allow us to gather important data about how water flows through the river following a period of extended dryness, the relationship between the river and groundwater, and the effect of such a water release on plants and trees. It’s also our hope that this will aid vegetation and wildlife affected by the ongoing drought.

As I and others have written previously, we’re seeing extraordinary stress on the riverside trees, the ribbons of green that flank the Rio Grande through New Mexico’s largest city.

The tradeoffs that we talk about every fall semester in the water resources class I teach, tradeoffs among competing and conflicting values, are becoming real. The motivating question I’ve used in my writing on water since my old newspaper days was to ask, as pointedly as I could, “When supplies run sort, who actually doesn’t get water?”

Two answers have become increasingly obvious in recent years along the Middle Rio Grande. What we’ve come to call the “accordion” of irrigated agriculture is squeezing, as pastures and fields without the super-senior water rights that apply to some of the irrigated lands of New Mexico’s Middle Rio Grande (or a supplemental well) go dry.

“The environment” is the other.

The question has never been “What do we say we value?”, but rather “What do we value enough to give up water in some other place?” This is about tradeoffs. More water in one place – an irrigated field or the river channel itself – necessarily means less water in some other place. My “what do we value enough to give up water” formulation shifts this from a question of what we say we value to what we actually value enough to give up water to preserve?

Behind the scenes for the last couple of weeks there has been an extraordinary effort underway to scrounge up some water currently in storage upstream for other purposes, and to rapidly put in place the tools to monitor the results. Nobody’s quite sure how much water will get how far into the bone dry Albuquerque reach of the river, how far downstream the pulse will make it, what the results might be for the riverside forest.

For my whole professional life, long before I shifted from newspapers to writing books, I had a joke when something remarkable happened: “That’ll be great material for my book!” This is that.

Sun’s almost up, I’m off to chase the water.

Continue reading ‘The science of tree diebacks in drought’ »]]> Of possible relevance to the current bosque dieback in New Mexico’s Middle Rio Grande? From PNAS:

Predicting forest resilience requires knowing whether trees can physiologically acclimate to drought. Drawing on global in-situ field experiments, we find a pervasive lack of functional adjustment in forest trees. Trees maintain stable hydraulic and photosynthetic capacities, enabling maximum carbon assimilation during favorable periods following rainfall. Nonstructural carbohydrate storage is also sustained. However, this physiological stability leads to a significant narrowing of hydraulic safety margins, indicating greater risk of tree mortality from hydraulic failure.

X. Liang, N.G. McDowell, D. Wang, B. Cui, J. Chen, K. Qiu, J. Luan, Z. Fan, X. Tan, X. Zhou, Q. Song, Z. Chen, Y. Jin, C. Liu, Y. Wang, Z. Li, H. Liu, Q. Liu, P. He, C. Yang, B. Liu, M. Deng, Y. Miu, X. Tan, X. Lu, J. Yan, W. Li, S. Liu, & Q. Ye, Declining hydraulic safety in a drier world, Proc. Natl. Acad. Sci. U.S.A. 123 (35) e2622754123, https://doi.org/10.1073/pnas.2622754123 (2026).

Continue reading ‘temperature 3.91 standard deviations above normal’ »]]>

An unusual year.

It was 96F (35.5C) when I rode my bike home after class at 6:15 p.m. last night.

“3.91 standard deviations above the long term record” is not terribly intuitive to me, the graphs above helped me visualize how extraordinarily unusual 2026 has been in Albuquerque. By all three normal measures – daily maximum, mean, and minimum – this year has been 2.5F (1.4C) warmer than the previous warmest years on record.

Top three panels are full year to date, bottom three panels are June 1 to date.

Continue reading ‘On the inevitability of change’ »]]> I spent an unhappy evening yesterday staring at data, trying to make sense of the inevitability of change. I slept poorly.

The Rio Grande through Albuquerque is dry, the Colorado River’s reservoirs are rapidly emptying and, unable to come to grips with this reality we have thrown up our hands and tossed the future of the West to the courts.

As a result of Federal Defendants’ issuance of the Final FEIS, ROD, and 2027-2028 Operating Guidelines, Nevada stands to experience a shortfall of 213,556 acre-feet at a 3.6 maf shortage, which constitutes approximately 71% of Nevada’s Colorado River entitlement. This shortfall will cause devastating environmental, socioeconomic, and health and human safety impacts to southern Nevada and its citizens.

Nevada is perhaps the best place to engage this conversation. I turned to Las Vegas back in 2015 when I was writing Water is For Fighting Over because it offered a perfect bait and switch: its Bellagio-fountained image of opulence and water waste contrasted with a reality of the most clear-eyed understanding of the inevitability that there will be less water.

The reality is that every community in the West can use less water than it is using now. We will all have to. But there is an absurdity to a plan that would require Las Vegas to cut 71 percent. That’s existential. Of course Nevada sued.

I’m reminded of what my friend John Entsminger said last December at the Colorado River Water Users Association meeting.

If you distill down what my six partners just said, I believe there’s three common things: Here’s all the great things my state has done. Here’s how hard/impossible it is to do any more. And here are all the reasons why other people should have to do more.

As long as we keep polishing those arguments and repeating them to each other, we are going nowhere.

The irony here is that Las Vegas is a community that has clearly demonstrated what the response to climate change in the West must look like – that has aggressively developed the tools of adaptation and water use reductions.

the Albuquerque story

40 years of declining outdoor vegetation and, by implication, water use reductions (browns and reds) and vegetation increases (greens) in Albuquerque. Map by John Fleck/Google Earth Engine/Claude

For my morning bike ride, I headed out into one of the reddish brown areas in the map above, in Albuquerque’s Northeast Heights. These are places where greenness – trees, lawns, gardens – has declined, as measured by satellite observations that go back to the 1980s. It’s a good proxy for consumptive use of water. While our indoor water is largely recycled, returned to the Rio Grande to support downstream ecosystems and water users, outdoor green is where the real water conservation action is. These oranges and browns represent places where the consumptive use of water has been reduced. My neighborhood. We, as a community, recognized that the amount of green around us was unsustainable. We reduced it.

I could have used Albuquerque as an example 10 years ago in Water is For Fighting Over – in fact, I did a bit in the book. Las Vegas was bigger and offered more storytelling juice, though. Plus Albuquerque’s ambiguities – the green bits on the map – pose a challenge to the narrative. Large areas of the Rio Grande Valley floor, neighborhoods with municipal service but where many homes use domestic wells and irrigation ditch water for outdoor landscaping, are beyond the reach of municipal water conservation programs.

Water use in Albuquerque, 2025, via OpenET. Blue is highest, yellows and browns are lowest

Here’s 2025 for the greater Albuquerque area via OpenET. The colors represent a rate of water use, which water nerds could think of as acre-feet per acre – blue is highest, then green-yellow-brown are lower. When you combine the rate – acre-feet per acre – with lower population density (fewer people per acre, much larger lots on the valley floor, many of them served with domestic wells and ditch water) you have a clear disparity in water use. Neighborhoods that have much lower per capita consumptive use of water (less green + smaller lots) are the ones most likely to have been conserving water, reducing their use. Neighborhoods that, because of the combination of large lots, greener landscapes and access to relatively unregulated supplemental water from shallow wells and ditches, have higher per capita use and are more likely to be increasing that use. (Our first cut at the data on pages 31 and following here.)

obligations

As I’ve written previously in this space, that big blue stripe down the middle of the map, the riverside forest we call the bosque, is seeing significant dieback.

We don’t have the science yet, or at least I don’t, to understand the multiple factors that are leading to the dieback. The obvious immediate causal element is that the river that feeds the shallow aquifer that feeds the cottonwood roots has gone dry. Whether the pressure from shallow aquifer pumping from domestic wells adjacent to the river, or deeper pumping from municipal wells, played a role in hastening the water table’s drop away from the cottonwoods’ roots is a question for the groundwater hydrologists.

Folks are working hard and fast on this.

But in the long run we face hard choices as a community. There is less water. There will be less green.