California’s use of Colorado River water this year on track to be the lowest since at least 1950

California’s use of Colorado River water this year is on track to be the lowest since at least 1949. (the latest forecast numbers are here)

My data on the early years is sketchy, but thanks to the folks at the Metropolitan Water District of Southern California, who recently shared an excellent dataset they assembled some years ago, I’ve got data back to 1950. The current forecast of 3.92 million acre feet of California use of Colorado River water is lower than any year in that record.

graph of California use of Colorado River water use, showing decline in recent years

California use of Colorado River water

There are a couple of things going on here. First, a good Sierra Nevada snowpack meant the Metropolitan Water District of Southern California didn’t need as much Colorado River water this year. But the Sierra snowpack, while good, clearly wasn’t the largest since 1950, right?

The second and arguably more important reason is a point Eric Kuhn and I make in our new book Science Be Dammed. While much of the book is about the problem of ignoring science on the supply side, we also argue in its concluding chapter that we are at risk of ignoring science on the demand side as well. Simply put, water use is going down. Here’s a squib from the book’s closing chapter:

There also is an empirical reality on the water demand side that has been insufficiently taken into account, but which provides a significant opportunity to help solve the river basin’s problems once we are willing to take it seriously. The widespread presumption that population growth means growing water demand drives much of the politics of water planning in the Colorado River Basin. But it is wrong. Simply put, we are consistently using less water. In almost all the municipal areas served with Colorado River water, water use is going down, not up, despite population growth. Water use in the basin’s major agricultural regions also is going down, even as agricultural productivity continues to rise. This is not limited to the Colorado River Basin. Such “decoupling” between water use, population, and economies is common across the United States.

I’ve been thinking about this a lot as I prepare for the this month’s Las Vegas gathering of the Colorado River Water Users Association. I’m moderating a sort of “what happens next” panel as we start talking, post Drought Contingency Plan, about the next steps in negotiating a new framework for post-2025 river governance.

We have some obvious stuff to talk about:

I’m hoping the discussions at CRWUA and after take seriously this remarkable shift we’re seeing on the demand side. As Eric and I argue in the book, it opens important space for solving our problems if and when we acknowledge that we don’t need as much water as we thought.


On New Mexico’s Rio Grande, the biggest year since 1995

We’re closing out 2019 with big flows on the Rio Grande through Albuquerque – at least big for this time of year. Flow at the Albuquerque gauge Friday topped 2,000 cubic feet per second, setting a record for Nov. 29 at a gauge that goes back to the mid-1960s.

graph of high 2019 flows on the Rio Grande through Albuquerque

2019 flows through Albuquerque

A couple hundred of those cubic feet per second were the result of a large storm, but mostly it’s institutional. In response to the big snowpacks of last winter, water managers are moving a lot of water down through the system, shifting it from upstream storage in El Vado Reservoir on the Rio Chama to Elephant Butte Reservoir. Elephant Butte is our Rio Grande Compact measurement point, and in a wet year like this our delivery obligation thereto goes way up.

In this regard, the gauge at the El Vado release point is really interesting.

2019 flows out of El Vado Dam, graphed

El Vado releases, 2019

Kuhn-Fleck webinar Jan. 22 to talk “Science be Dammed”

Eric and I will be doing a Webinar Jan. 22, sponsored by the American Water Resources Association:

In their new book Science Be Dammed, Eric Kuhn and John Fleck explain how even when clear evidence was available that the Colorado River could not sustain ambitious dreaming and planning, river planners and political operatives irresponsibly made the least sustainable and most dangerous long-term decisions. Arguing that the science of the early twentieth century can shed new light on the mistakes at the heart of the over-allocation of the Colorado River, Kuhn and Fleck delve into rarely reported early studies, showing that scientists warned as early as the 1920s that there was not enough water for the farms and cities boosters wanted to build. Contrary to a common myth that the authors of the Colorado River Compact did the best they could with limited information, they show the boosters selectively chose the information needed to support their dreams, ignoring inconvenient science that suggested a more cautious approach.

Registration here

Historic New Mexico Instream Flow Right Approved

Granting a New Mexico Instream Flow Right

Water policy folks in other western states may yawn at this, but in New Mexico it’s a big deal. The New Mexico Office of the State Engineer has approved the state’s first instream flow water right. Here’s a summary from Audubon, the group that put the deal together, explaining how it works.

The deal would allow water to flow down a stretch of the Rio Gallina, just upstream from its confluence with the Rio Chama. Previously the water had been diverted during high flows to a holding pond to irrigate about 40 acres of land on the Gallina’s south side.

It has long been believed that New Mexico law allows instream flows, but the right is implicit, not explicit. Here is the explanation from the folks at the Utton Center at the UNM School of Law:

In 1998, the Attorney General of New Mexico issued an opinion stating there is nothing in the New Mexico Constitution,statutes, or case law barring the State Engineer from approving an application to change the purpose of use of an existing water right to instream flow. The opinion concluded that New Mexico law does not require a diversion to beneficially use water and a court would likely define beneficial use to reflect current concepts of public interest,waste, and reasonable use. The Office of the State Engineer (OSE) indicated, in a parallel memorandum, that it could act favorably onan application for instream flow if there was sufficient dominion and control over the flow, such as accurate and continuous gauging devices to perfect the right and demonstrate continued use of the water.

We haven’t had anyone actually try to establish such an instream flow in the two decades since. Until now.

Building resilience in New Mexico water – Water Dialogue meeting, Jan. 9

I look forward every year to the annual gathering of the New Mexico Water Dialogue. It’s always a great meeting – the speakers etc. But even more so, it’s a great gathering of our version of “the network” – the diverse collection of folks across cultures and geographies in our state who understand the importance of collective dialogue about our shared future.

This year we’ll be hearing from Dave Gutzler (UNM climate) and Melinda Harm Benson (UNM geography, a resilience scholar who’s helped many of us think carefully about how to frame our goals and understandings of the way our water system works). I encourage folks among my New Mexico readership to click the link above and sign up to attend.

If trends continue, Phoenix is on a path to groundwater “safe yield”, according to new research

If past trends in greater Phoenix – agricultural land transitioning to urban – the area is on track to groundwater “safe yield”, according to new research by an Arizona State University team:

Under (business as usual) conditions where population is expected to increase and agricultural activities to gradually decrease, our results indicate a reduction in the use of groundwater of ~23% that, in turn, will likely allow achieving safe-yield. If the decrease in agricultural activities will be less drastic or remain constant in time (i.e., more food will be produced locally), additional water from more energy-intensive water sources (groundwater and CAP) will be needed.

A shift in the trend – less ag land decline – makes it less likely that Phoenix would meet the goal, the researchers found. A shift to more renewables means an even better prognosis for groundwater, given the significant use of water for power plant cooling. And it probably goes without saying that a multi-decadal drought would make things harder.

The paper is Guan, Xin, et al. “A metropolitan scale water management analysis of the food-energy-water nexus.” Science of The Total Environment 701 (2020): 134478. Found behind a paywall here.

Imperial Irrigation District’s line in the Salton Sea sand

The Imperial Irrigation District board will take up a resolution this afternoon drawing a sharp line. If action isn’t taken to deal with the Salton Sea, the historic early-2000s deal that attempted to untangle California’s Colorado River overallocation (the “Quantification Settlement Agreement” or QSA) “will have been breached”:

Imperial Irrigation District board resolution language

Imperial Irrigation District board resolution language

The full text of the resolution and accompanying memo is here.

New paper with Anne Castle on Risk of Colorado River curtailments in Colorado, Upper Basin

The framing questions I’ve used for my work on water over the last decade go something like this:

  • When the water runs short, who doesn’t get theirs? What does that look like?

Those are the motivating questions behind a new paper Anne Castle and I have written. We’ve also added an increasingly important third question:

  • Given the answers to the above, what should we do now to prepare?

The paper, The Risk of Curtailment Under the Colorado River Compact, is available for free download at SSRN. (I think you have to sign up for an account to actually download the paper, but it’s free.)

Here’s the nut:

Water supply in the Colorado River could drop so far in the next decade that the ability of the Upper Colorado River Basin states – Colorado, Utah, Wyoming, and New Mexico – to meet their legal obligations to downstream users in Nevada, Arizona, California, and Mexico would be in grave jeopardy.

Legal institutions designed nearly a century ago are inadequate to address the significant risk of shortfall combined with uncertainty about whose water supplies would be cut, and by how much.

This report indicates that declines in the Colorado River’s flow could force water curtailments in coming decades, posing a credible risk to Colorado communities and requiring serious consideration of insurance protection like demand management.

The risk is most easily understood in this graph, from new analysis done by the Bureau of Reclamation. It basically shows that a repeat of the most credible drought in the recent record, that of the early 2000s, could in a matter of a few years drop levels in Lake Powell to “power pool” – the level at which Glen Canyon Dam can’t generate electricity, and at which it begins to become difficult to get enough water through the dam to meet downstream delivery obligations under the Colorado River Compact:

Graph of Lake Powell risks. Source: USBR

Lake Powell risks. Source: USBR

The line screaming down toward the bottom, in sort of dark greeny color, is the one to look at. A repeat of the drought of the ’00s could, with just four dry years, drop Powell to “power pool” levels. This is not some scary future climate change scenario. This is something that has actually happened in the recent lifetimes of folks working on the river today.

Our contribution (and really all credit to Anne’s thinking here, she’s the one who did most of the heavy lifting) involves a detailed discussion bringing together well-understood climate science and hydrology risks with less well understood uncertainties in the legal system. We have a lot of people right now arguing essentially, “Well, the Law of the River shows those other people will have to have their water cut!” So lawyer up!

There be the dragons.

Anne and I believe it’s important to have a clear and public discussion about the significant unresolved Law of the River questions as well evaluate our hydrologic risk, so we head into the next phase of Colorado River management discussions with our eyes fully open.

We shouldn’t over-emphasize scary worst case scenarios, because the odds that we’ll be on that worst case line are low. But they are not zero (this is a drought that actually happened not that long ago!), and failing to have a plan seems like something worth trying to avoid.

Among the options Anne and I consider:

  • “Demand management” – essentially reducing water use now and banking the savings as a hedge. This has been done with great success in the Lower Basin, effectively avoiding the risk of curtailment there by banking water in Lake Mead.
  • Negotiating broad agreements with the Lower Basin, trading off some of our risk against some of theirs.
  • “Going bare” – deciding that the costs of insurance (by “insurance” we mean foregoing water use now as a hedge against future risk) are too high.

What does it take to win public acceptance of wastewater reuse?

Q: What does it take to win public acceptance of direct potable reuse of wastewater?

A: “a daily lived experience with the effects of drought or water scarcity”

That’s one of the key findings from a new paper I coauthored with a team led by the University of New Mexico’s Caroline Scruggs, working with Water Resources Program graduate student Claudia Pratesi: Direct potable water reuse in five arid inland communities: an analysis of factors influencing public acceptance.

We were interested in better understanding the connection between the technocratic answers to the reuse question (Science says it’s safe!) and the sometime cultural response (Yuck!). Dr. Scruggs has been working on reuse for years. I jumped in because of my interest in the science-policy interface, and in particular in the governance piece – how do decision making structures influence the kind of decisions that get made in a situation like this. As is the case with stuff like this, Claudia did a lot of the heavy lifting as part of her masters project.

I loved doing this project in part because of the way it embodied the interdisciplinary work we do in the University of New Mexico Water Resources Program – understanding the interface between the technical sciency parts of water management and the cultural and institutional pieces that are so important in getting stuff done.