By John Fleck and Jack Schmidt

Stable isn’t good enough.

Preliminary year-end Colorado River numbers are stark. Total basin-wide storage for the last two years has stabilized, oscillating between 30 and 27 maf (million acre-feet), where storage sits at the start of 2025[1]. That is lower than any sustained period since the River’s reservoirs were built (Fig. 1). Stable is better than declining, but we did not succeed in rebuilding reservoir storage during 2024’s excellent snowpack but modest inflow. Although reservoir storage significantly increased after the gangbuster 2023 snowmelt year, we have not protected the storage gained in 2024 when inflow to Lake Powell was ~85% of normal from a 130% of normal snowpack. We can’t rely on frequent repeats of 2023; we must do better at increasing storage in modest inflow years like 2024.

Why is this happening?

Less water.

The phrase “the new normal” can be misleading, suggesting a new, more stable state for the climate. It’s not gonna be stable. But by one reasonable measure – total estimated natural flow in the Colorado River at Lees Ferry – Calendar Year 2024 was typical of the first quarter of the 21st century, with a preliminary estimate of 12.1 million acre-feet “natural flow.” Thus, the calendar year average annual natural flow at Lees Ferry between 2000 and 2024 has been 12.4 maf/yr, down from 14.3 maf for the period 1930-1999. An additional 770,000 af/yr in side inflows between Lees Ferry and Lake Mead add to the available water supply[2].

That we made the cuts needed to stabilize reservoir levels with a natural flow at Lees Ferry as low as 12.1maf would have been a substantial achievement in the wetter “before times.” Now, it’s table stakes. The most important point is that we absolutely did not rebuild storage in 2024, despite a 130 percent snowpack. We must do better in reducing total basin consumptive use.

Once again in 2024, we saw substantial water use reductions among the states of the Lower Colorado River Basin. Total U.S. Lower Basin main stem use of 6.08 maf is the lowest since 1985 (meaning the lowest since the Central Arizona Project came on line). California’s use, based on preliminary numbers published by Reclamation seems to be the lowest since 1950, and use by the Imperial Irrigation District seems to be the absolute lowest in a dataset that goes back to 1941. These are important achievements, to be celebrated.

With regard to the other two major U.S. areas of use – Lower Basin tributaries and the Upper Basin as a whole – we have no idea what 2024 consumptive use was. This is a problem. Lower Basin main stem use is quantified through Reclamation’s annual accounting reports and reported on a nearly daily basis during the course of the water year. River flows and reservoir levels across the basin are similarly reported in public, transparent ways. That’s how we’re able to provide the data you see above. Anyone can download and crunch the numbers. The general public can’t readily do that for consumptive use in the Upper Basin or Lower Basin tributaries.

As Elinor Ostrom noted in her classic book Governing the Commons, shared understanding of the resource is crucial to successful water management. Increasingly, areas of uncertainty have become contested ground, as the genuine technical uncertainties collide with the motivated reasoning of political actors across the basin.

With respect to the Upper Basin, we note that the rhetoric that Upper Basin water users suffer shortages in dry years has shifted to a broader claim that Upper Basin users always suffer shortages. We quote here from the Upper Basin states’ January 2 press release: “There are acute hydrologic shortages in the Upper Basin every year – there simply isn’t enough water in any year to satisfy current needs in the Upper Basin every year. The Upper Basin has made uncompensated cuts to their water users every year for the past 24 years.” Some of the data to support this assertion was presented at the December 2024 UCRC meeting, and we look forward to a more complete and transparent accounting of these data, because these data are crucial to a robust Colorado River management discussion. The Upper Basin’s experience of “acute hydrologic shortages … every year” is exactly what John Wesley Powell described in 1878 in the first edition of The Arid Lands Report.  Nothing has changed, and the challenge of agriculture throughout the watershed has been well known for 150 years. We also note that consumptive use data throughout the basin has not been integrated with the important findings of Richter et al (2024) who documented the proportion of water used by different agricultural sectors. They estimated that 55% of all Colorado River water use supplies livestock feed.

We leave a discussion of Lower Basin tributary use for another post but note that in both the cases of the Upper Basin use and Lower Basin tributary use, the numbers are entangled in the current Upper Basin-Lower Basin feud, which makes serious efforts to think about how to manage water at the Basin scale, rather than simply defending parochial interests, much more difficult. It is important that the general public not employed by a state or water agency, and therefore not beholden to local parochial interests, help the basin community as a whole navigate these technical issues.

Conclusion

The stable reservoir levels at the end of 2024, despite another year of deep Lower Basin water use reductions, should be cause for alarm. Deeper cuts are needed. But without a shared understanding of water use elsewhere in the basin, we’re flying blind.

[1] Basin-wide reservoir storage reached a peak of 29.7 maf on 13 July 2023 and was subsequently drawn down to 27.5 maf by mid-April 2024. Inflow from 2024 snowmelt rebounded basin-wide storage to 30.0 maf on 6 July 2024, and storage was subsequently drawn down to 27.4 maf by 31 December 2024. Retention of storage in Lake Mead and Lake Powell has been somewhat better during the same period. Combined storage in Lake Mead and Lake Powell peaked in mid-July 2023 at 18.0 maf, declined to 17.1 maf by mid-May 2024, increased to 18.5 maf on 8 July 2024, and was 17.3 maf on 31 December 2024. Thus, storage in the two largest reservoirs at year’s end was slightly greater than it was at its spring 2024 minimum just before storage increased when significant snowmelt reached Lake Powell.

[2] This estimate is calculated as the difference between annual flow measured just upstream from Diamond Creek in western Grand Canyon and measured at Lees Ferry.

By Eric Kuhn and Jack Schmidt

The press coverage of the December 2024 Colorado River Water Users Association (CRWUA) meeting mostly focused on the ongoing stalemate between representatives of the Upper and Lower Division States over their competing proposals for how the Colorado River Systems’ big reservoirs will be operated after the 2007 Interim Guidelines terminate in 2026.  The headlines included words such as “turbulent”, “bitter”, “bluster”, and “spar”. Indeed, there was tension in the air, and the potential for interstate litigation was a topic of much discussion both on the formal agenda and in the hallways where, traditionally, progress is often made between competing interests.

While the press focus on the tension and divisiveness was unavoidable, I believe that there were good reasons for some guarded optimism.

For the ongoing effort to renegotiate the post-2026 operating guidelines, a consortium of seven environmental NGOs has also made a detailed proposal.  Their proposal is referred to as the “Cooperative Conservation” proposal. One of the four action alternatives that Reclamation will analyze, Alternative #3, is patterned after the NGO submittal.  At CRWUA, John Berggren of Western Resource Advocates, who along with Jennifer Pitt and others prepared the proposal, made a presentation on the proposal.  Like the other submitted proposals, the cooperative conservation alternative proposes sophisticated operational rules for Lakes Mead and Powell based on combined system storage and actual hydrology. Where the Cooperative Conservation proposal breaks new ground is the concept of a Conservation Reserve Pool, and this idea could lead the basin toward a practical on-the-ground solution. Indeed, the Gila River Indian Community introduced at CRWUA a similar concept in the form of a Federal Protection Pool made up of stored water in both Lake Powell and Lake Mead. These proposals, taken separately, together, or in some combined and moderated form, might serve as a catalyst for compromise.

As proposed, both the Conservation Reserve Pool and the Federal Protection Pool would be filled with water conserved by reductions in consumptive use and perhaps augmentation from programs in both basins and this water could be stored anywhere in the system. This water would be “operationally neutral” and thus invisible to the underlying system management operating rules. From an accounting perspective, this Pool would “float” above other water in the reservoirs. Floating Pools operate separately from and above the prior appropriation system of water allocation on the Lower River and are invisible to the rules that dictate annual releases from Glen Canyon Dam. Thus, these proposals impart important operational flexibility.  In many ways, Floating Pools split the baby—they incentivize innovative conservation measures that allow participants to find value they would not have been able to realize under the prior appropriation system—yet they insulate the prior appropriation system and thus are more protective of higher-priority water users than operationally non-neutral ICS.  It’s a stretch to say there is something here for everyone, but there may be enough to kick-start otherwise stalled conversations.

In their proposal, the Lower Division States have offered to take up to 1.5 maf/year of mainstem shortages. Where the two basins remain deadlocked is what happens in those years when shortages exceed the amount the Lower Division States are willing to accept.  The Lower Division States have proposed that the two basins share the additional required shortages up to a maximum shortage of 3.9 maf/year.  The Upper Division States have said, “No, because we already suffer large hydrologic shortages in dry years, and we have not used our full compact entitlement; the Lower Division should cover all of the shortages.” In their presentation, however, the Upper Division Commissioners (UCRC members) left the door open for continuing discussions between the two divisions. In his remarks, New Mexico Commissioner Estevan Lopez stated that under what he referred to as “parallel activities”, the Upper Division States might be willing to discuss conserving “100,000, maybe 200,000 acre-feet per year.”

Water in Floating Pools could be used for a variety of purposes including environmental management, fostering binational programs, and supplementing scheduled water deliveries. During his CRWUA presentation, John Berggren mentioned an obvious use for this pool.  Water stored in the Pool by conserved consumptive use programs in the Upper Division States could be used as an Upper Division contribution during years when mainstem shortages to the Lower Division States exceed a negotiated amount.  Of course, the Lower Basin is unlikely to accept Upper Basin creation of Floating Pools made up of water for which there is no current consumptive use. This water is already “system water” and is now being used by existing Lower Basin water agency. Thus, it would be necessary to develop a program to account for and certify savings in the Upper Basin.  Further, the thorny problem of shepherding (legally protecting the conserved water so that it ends up in system storage) needs to be overcome. For a perspective on this issue, see Heather Sacket. Undeveloped Tribal water is a controversial sticking-point in this regard, with strong feelings and strong arguments on all sides.

If the Upper Division States were to conserve 200,000 acre-feet per year for five years and deposit that saved water in a conservation reserve “Floating Pool”, something like 900,000 acre-feet could be available for shortage sharing (after accounting for reservoir evaporation). (We use 900,000 af as an example only, how much water the Upper Division States would have to contribute and maintain in a Floating Pool would have to be negotiated between the two divisions.)  In their presentation, the Lower Division principals pointed out that had their proposal been in place beginning in 2007, there has yet to be a year when shortage sharing would have been required. Note, this conclusion is very sensitive to “initial conditions.” In 2007, total storage in Lake Mead and Lake Powell was about 8 maf more than it is today. If the 21^st century hydrology continues, shortages greater than 1.5 maf/year are likely to occur.

What would the Upper Division States get in return?  During the term of the new post-2026 operating guidelines (which we all assume will also be “interim”), the Upper Division would benefit by the Lower Division agreeing to remove the threat of litigation over a “compact call.” For a perspective on the potential impacts of a “call” in Colorado see The Risks and Potential Impacts of a Colorado River Compact Curtailment on Colorado River In-Basin and Transmountain Water Rights Within Colorado.

Carefully crafted with appropriate guardrails, Floating Pool concepts can be a catalyst for compromise between the two divisions that give both parties something they need.

How do Floating Pool alternatives fit with the Schmidt, Kuhn, Fleck management approach?  Based on our conversations with the authors of the cooperative conservation proposal, we believe the two approaches agree — that our management proposal fits on top of and complements their proposal quite well.  In my presentation at CRWUA, I emphasized that, like future hydrology, there is great uncertainty in the future needs of the river’s ecosystem and society’s values.  It’s almost a certainty that in the future, prescribed annual releases from Glen Canyon Dam will cause an unacceptable and unanticipated outcome to some river or reservoir resource. When that happens, our flexible management approach and accounting system keeps the basins “whole.”

Is using the concept of Floating Pools as a catalyst to break the stalemate between the two basins without warts? – of course not.  There are important considerations regarding the use of undeveloped water—Tribal or otherwise, and the devil is in the details when it comes to developing appropriate guardrails for annual and total accumulation in such a Pool, the number and type of participants, annual debits, and other important qualifications. Even conserving 100,000 acre-feet per year in the Upper Division States, with acceptable verification, could be a stretch, especially if there is less federal money in the future, as there almost certainly will be.  Finally, it might put off addressing fundamental problems with the law of the river until the new post-2026 operating rules again expire. When they do, the 1922 Compact and 1944 Treaty with Mexico will still be in place, and these agreements collectively allocate 17.5 maf/year of consumptive use on a river that is only producing 13-13.5 maf/year of water at the international boundary (and runoff continues to decline).  What the Floating Pool concept might accomplish is to significantly reduce the temptation and threat of unpredictable interstate litigation, keep the basin’s stakeholders talking to each other, and give us time to move toward more foundational change in how the river is managed.

If traffic to this blog is an indicator, y’all are really interested in thoughtful independent analysis of the standard talking points in the Colorado River negotiations. Also, the work of my longtime collaborator Eric Kuhn (which is unsurprising, I’ve long been really interested in Eric’s work).

Three of the four most-read Inkstain posts this year were Eric’s (one of the three a double-byline piece with me):

1. No Simple Disputes, Eric’s explanation of the problems posed by the failure to define “consumptive use,” and how that failure weakens the Upper Basin’s argument about Lower Basin tributary use. (Eric’s version is wonky, I came back a day later to de-wonkify it for Inkstain readers, though Eric’s technical version got way more reads.)
2. The Compact Tripwire, a post Eric and I wrote together on the risk of total Upper Basin deliveries past Lee Ferry dropping below 82.5 million acre feet over a ten-year period, and the risk of Compact litigation that sets up.
3. What happens if there is no agreement on post-2026 Colorado River Management is Eric’s dive into the rules that would apply if we don’t have any agreement or federal intervention – Eric’s version of the “no action alternative.”

(The fourth was a weird riff on the Russian anarchist thinker from the late 1800s-early 1900s Peter Kropotkin, a pair of wire cutters, and a pedestrian alley behind the gas station by my house. It had a bit of a viral moment, though my efforts to think through the connection between Kropotkin and Colorado River governance failed.)