On the Colorado River, there are no Simple Disputes

By Eric Kuhn

One of the commentors to our January 19th, 2024, blog post titled “Are We headed for the First Colorado River Compact Tripwire?” – John C. (who, by-the-way runs a very talented water resources engineering firm) raised several finer points to explore further:

The first point deals with obligations of each Basin to contribute water needed to meet U.S. obligations to Mexico under the 1944 Treaty. The second deals with the question of how to measure, and therefore manage, in the context of overall Colorado River Basin management, the use of tributary water in the Lower Basin. Both represent unresolved legal questions with enormous potential impacts on the allocation and distribution of the shrinking Colorado River – questions we have avoided dealing with by draining the Basin’s reservoirs. We no longer have that option.

The two issues have been disputed for decades. They are, of course, totally inter-related, and when one peels back the layers of each, the problems get so complicated that the only real solution may be for the Basin’s states and other stakeholders to ignore their past positions and grievances and negotiate a river management approach that works on the river we have today, even if that means changes to the foundation of the Law of the River, the 1922 Compact.

Mexico Obligation

The different interpretations of the Upper Basin’s delivery obligations to Mexico under Article III(c) are well understood throughout the Basin. III(c) says that water for Mexico should be provided from “surplus”. If there is no surplus, the Upper and Lower Basins much each provide half the necessary water. But there has never been agreement on what that language means in practice. This unresolved uncertainty has enormous implications for how much water is available to each basin in the future.

The Lower Division States take the position that there’s no current “surplus,” as defined by Article III (c), thus the Upper Division States must deliver at Lee Ferry 50% of however much water is required to be delivered under the Treaty. The annual delivery is normally 1.5 maf/year, but under either the “extraordinary drought” provision of the Treaty, or Minutes, it could be less. In 2023, it was 1.4 maf.

The Lower Division States’ position would dictate an average annual delivery of 8.25 maf/year at Lee Ferry, 7.5 maf under Article III(d) + 750,000 af under Article III(c). The 8.25 maf includes an average contribution of 20,000 af/year from the Paria River and would be adjusted for the occasional annual delivery of less than 1.5 maf. Veterans of the negotiations that led to the 2007 Interim Guidelines will recall that Arizona’s Herb Guenther always brought with him to the meetings a posterboard sign with “8.25” written on it.

Going back to the 1970 decision by the Secretary of the Interior to set the “minimum objective release” from Glen Canyon Dam at 8.23 maf/year, the Upper Division States have consistently taken the position that their annual obligation Mexico has never been formally defined and, whatever it is, it is not 750,000 af/year, every year. While they vigorously complained, they never chose to formally challenge the issue in court or in Congress, perhaps because they concluded that they couldn’t show that any of their interests were injured. Today, based on post-2000 hydrology, that dynamic may have fundamentally changed.

The basic position of each basin has not changed. If anything, because the stakes are much higher, the positions have hardened. In a December 20, 2022, scoping letter to Reclamation, Arizona’s Tom Buschatzke, and Ted Cooke, wrote: “Article III(d) and (c) prohibits the Upper Division States from depleting the flow of the river at Lee Ferry below a rolling 10-year aggregate of 75 maf plus one-half of the Mexico delivery obligation. With reduced releases from Glen Canyon Dam potentially analyzed under the SEIS, if the 10-year rolling aggregate falls below the required aggregate volume, the Upper Division States could be subject to a “Compact call” that would require a reduction in consumptive use in the Upper Basin.  In footnote 1, they add “A “surplus” currently does not exist because natural flows in the Colorado River have not exceeded 16 maf in the past 10 years.”  In their August 15, 2023, scoping letter, the three Lower Division States write: “The Post-2026 EIS must analyze whether alternatives are consistent with the 1922 Colorado River Compact non-depletion obligations and delivery obligations to Mexico. Alternatives should include actions necessary to ensure compliance with such obligations.”

The Upper Division States are equally adamant that because of overuse in the Lower Basin, they currently have no annual obligation to Mexico under Article III(c). Note that I used the term “Lower Basin” because under the 1922 Compact, the Lower Basin includes the upper Gila River in New Mexico, where uses are small, Kanab Creek in Utah and Arizona, again uses are small, and the Virgin River, shared by Nevada, Arizona, and Utah, where uses are not small. The Virgin River is the water supply for the rapidly growing St. George area.  As a state, Utah consumes the second largest amount of Lower Basin tributary water, about 150,000 af/year, albeit much less than Arizona.

In recent public presentations, Colorado Commissioner Becky Mitchell has stated that the Lower Basin’s total annual use, including tributaries and reservoir evaporation, were 10.5 maf in 2020, 10.8 maf in 2021, and 10.4 maf in 2022, far more than the Lower Basin’s compact apportionment (7.5 maf under Article III(a) plus 1.0 maf under Article III(b)). Their position is that the Lower Basin’s overuse is “surplus” water that must first be used to meet the 1944 Treaty obligations to Mexico before the Upper Division States have any obligation to Mexico, a position the Lower Division States do not agree with.

The situation is messy. As I explain below, Mitchell’s 10-plus million acre foot calculation is based on analysis that contains a hidden assumption about the correct way to measure water use, an assumption at odds with the method the Upper Basin has traditionally used to measure its own water use. But when one peels back the layers, it’s even messier. First, there is no agreement on whether the obligation of the Upper Division States to Mexico is calculated on an annual basis, a ten-year rolling aggregate basis, or something else (I’m in the something else camp). The predominant position the Upper Division States is, as mentioned in John’s comments, that the since the 1944 treaty provides for an annual delivery to Mexico (which can change), therefore, the obligation of the Upper Division States is determined annually. As can be seen by the language in the Arizona and Lower Division States letter, the Lower Basin states’ position is based on a ten-year rolling aggregate. The logic of this position is that the last sentence of Article III(c) states: “whenever necessary the States of the Upper Division shall deliver at Lee Ferry water to supply one-half of the deficiency so recognized in addition to that provided in paragraph (d).”  Paragraph (d) is a ten-year requirement; does it make sense to add an annual requirement to a ten-year requirement? Further, the data necessary to determine whether a deficiency exists (and thus the obligation of each basin) would not be available until well after the water year is over.

My reading of the reports of the compact commissioners, their Congressional testimony, and the minutes of both the 1922 and 1948 suggests a third possible alternative.  The negotiators of the 1922 Compact, the 1944 Treaty, and the 1948 Compact considered the surplus to be the difference between the average long-term natural flow of the river at the international boundary and 16 million acre-feet, the aggregate of the apportionments made by Articles III(a) and III(b). During the negotiations of the 1948 Compact, Colorado’s Royce Tipton and Arizona’s Charles Carson laid out the logic. Based on the comprehensive hydrologic analysis conducted by Reclamation (Appendix I of the 1947 Comprehensive Report), the estimated long-term natural flow below the confluence of the Colorado and Gila Rivers was 17.7 maf/year. Subtracting 16 maf left an average surplus of 1.7 maf, 1.5 maf for Mexico and about 200 kaf for surplus uses within the United States. Upper Division State officials argued that with this hydrology there was no deficiency. Colorado’s Tipton and Clifford Stone (its 1948 Compact Commissioner), however, did acknowledge that the location of the surplus was an important factor.

With their 1940s understanding of the river hydrology, the Upper Division States did not want the deficiency calculated either on an annual basis or a ten-year running average. They understood that in both cases, they would be required to deliver more water to Mexico than using the long-term average. Under an annual determination, there would be many years (~50%) when there was a deficiency. Under the ten-year rolling average, there would be long periods when it would be below 16 maf/year and there would be a deficiency (the 1930s drought period for example) but provided the long-term average was more than 17.5 maf/year, there would be no deficiency. Tipton also made the point that in the future, the construction of additional storage reservoirs (like Lake Powell) would effectively “equate” the river. Today’s problem with this approach is that in the 1940s, the basin’s water managers assumed a level of “stationarity” (future river flows can be predicted by what happened in the past) that because of climate change does not exist today.

An additional problem we have today is the calculation of the deficiency is based on the natural flow at the international border with Mexico, not Lee Ferry. Note that the Arizona letter states, “natural flows in the Colorado River have not exceeded 16 maf/year.” That statement is very likely true, but there are no data to back it up. Unlike Lee Ferry, there are no recent calculations of annual natural flows at the international border. There is no Colorado River system natural flow database. The existing database includes natural flows to Lee’s Ferry, but downstream to the Imperial Diversion Dam, Reclamation acknowledges that they have little confidence in these data and much of it is not based on reconstructed natural flows.  Importantly, the existing natural flow database does not include the Gila River system.

The last widely published estimate of natural flows at the international border was completed by the Bureau of Reclamation nearly eighty years ago (Appendix I). These data were used during the 1944 Treaty ratification hearings and, to a lesser extent, by the 1948 Compact negotiators. Appendix I shows an average natural flow at the border of 17.72 maf/year. At Lee Ferry, it was 16.41 maf/year (based on1898-1943). Assuming a similar relationship between the flows today, from 2000-2023 the estimated natural flow at the border, including the Gila, would be approximately 13.5 maf/year (12.44/16.41 x 17.72). Note, because of climate change, which appears to have a greater impact on the southern tributaries of the Colorado River system, the relationship may no longer be reasonable.

Updating the natural flow database to include the Gila River has been suggested by Upper Division State officials, but Arizona has historically objected. Clearly this would not be an easy task and there would be large uncertainties, especially estimating with any certainty natural losses on the Colorado River below Hoover Dam and on the Gila River from the Phoenix area to Yuma under today’s climatic conditions.

Lower Basin Tributary Use

The Gila River is also the central subject of John C.’s second comment that Arizona, California, and Nevada should be concerned that including mainstem consumptive uses, tributary consumptive uses (including those in Utah and New Mexico), reservoir evaporation, and maybe system losses, the Lower Basin total consumptive uses exceed its compact apportionment of 8.5 maf/year. Alternatively, Lower Basin tributary consumptive uses far exceed 1.0 million acre-feet – if one believes Article III(b) was intended to only cover Lower Basin tributaries.  The problem with this argument is that there is no 1922 Compact definition of “beneficial consumptive use” (the “commodity” the Compact apportions). This is especially important for the Lower Basin tributaries.

There are different interpretations among the states and between the basins of how “beneficial consumptive use” should be defined and therefore measured. Each has a strong legal argument in its favor. But their approaches result in vastly different numbers, and as my co-author John Fleck has written, “There’s not enough water for all the lawyers to be right.”

Article VI of 1948 Compact defines and provides a method measuring compact apportionments for the Upper Basin. The 1964 decree in Arizona v. California defines how to measure the mainstem apportionments made to the Lower Division States under the 1928 Boulder Canyon Project Act. Since the 1963 decision did not interpret the 1922 Compact and there is no Lower Basin Sub-Compact, there is no accepted or defined method for measuring 1922 Compact apportionments on the Lower Basin tributaries (and arguably the entire Lower Basin).  The methods used by the 1948 Compact and the 1964 Decree are very different. The 1964 Decree uses the concept of “diversions minus return flows.” It comes from the language of the Boulder Canyon Project Act. Stream losses and reservoir evaporation from Hoover Dam to the points of diversion are not considered a use, but rather a limitation on the available supply.

The 1948 Compact approach for defining and measuring consumptive use under Article VI is based on what was referred to as the “stream depletion” theory. Consumptive uses for the Upper Basin and for the individual states are measured as the net impact of man-made depletions on the natural (AKA virgin) flow of the Colorado River at Lee Ferry using the “input-output” method. The 1948 Compact gives the UCRC the authority to change the method by unanimous approval. The UCRC has instructed its staff to identify an alternative to the input-output method, so this may happen soon.  Article VI was one of the most debated and carefully written articles in the 1948 Compact. The negotiators had a clear objective in mind. They wanted to carefully define how to measure compact apportionments so that water made available for consumption through “salvage by use” would not count as compact apportioned use.

The issue of salvaged water was a major dispute among the basin states in the 1940s and 1950s. Simply put, salvaged water is water made available for use by the reduction of natural losses caused by the development of the river. The best example of salvage by use is Arizona’s Gila River. As the Gila River and its two major tributaries, the Salt and Verde Rivers, leave the rim country upstream of Phoenix, they have a combined average natural flow of over 2.0 maf/year (2.3 according to the 1947 report). As the river flows to its confluence at Yuma, in its natural state it loses about 1.0 maf/per year. By diverting and using the entirety of Gila River’s waters upstream, these losses are eliminated. Thus, Arizona can consume a million af/year more water than what the Gila River contributes to the natural flow of the Colorado River system.  Under the “stream depletion” theory, which was favored by Arizona and the Upper Division States, Arizona is only charged for a million acre-feet of 1922 Compact apportionment. Under California’s “diversions minus return flows” theory, also favored by Nevada, all 2+ maf/year of Arizona’s Gila River consumptive use would be charged as 1922 Compact apportionment.

The Upper Basin adopted the stream depletion theory during an era when the states were competing for every acre-foot possible. They thought could benefit by 400,000 -600,000 af per year. Simply put, in years when the water was physically available, the Upper Basin could consume 7.9 – 8.1 maf/year while only depleting the natural flow of the river at Lee Ferry by 7.5 maf/year (their compact apportionment). The negotiators never contemplated that 75 years later, the water available to the Upper Basin would be far less than 7.5 maf.

During the negotiations of the 1948 Upper Basin Compact, the decision to use the stream depletion theory was thoroughly debated. Wyoming’s legal advisor, W. J. Wehrli, warned the other states that using this definition would benefit the Lower Basin far more than the Upper Basin. Additionally, he noted that it could reduce the amount of surplus water under Article III(c), potentially increasing the obligation of the Upper Division States to Mexico. Wyoming ultimately fell in line and agreed to the Article VI definition. During the Congressional debate over the authorization of the Central Arizona Project, Upper Division State officials (primarily Tipton and Stone) testified in favor of the stream depletion theory, arguing that the negotiators of the 1922 Compact intended this method to measure apportionments. Note, the compact does not include a definition of “beneficial consumptive use,” they made their case based on an analysis of the minutes and the use of the term “depleted” in Article III(d).

The Upper Division States make a rhetorically powerful public argument that in the face of climate change, overuse in the Lower Basin is the central problem in the Colorado River Basin that must be solved to reach a sustainable future where water use, and the available supply are in balance. The argument is that when mainstem uses, reservoir evaporation, system conveyance losses, and tributary consumptive uses (in Arizona, Nevada, New Mexico, and Utah) are added together, the Lower Basin’s total use exceeds ten maf/year, perhaps as high as eleven maf/year. The Lower Basin’s compact apportionment, however, is only 8.5 maf/year (perhaps 7.5 maf/year depending on how Article III(b) is interpreted), resulting in an overuse of at least 1.5 maf/year. Such an overuse has major policy implications:

  • If the Lower Basin is overusing its compact entitlement, why should the Upper Basin, which is using far less than its apportionment, reduce its uses to help bring the system into balance?
  • Should the Lower Basin’s overuse be considered “surplus” water under Article III(c)? If so, should this surplus water be delivered to Mexico before the Upper Division States have any obligation to deliver half of the deficiency to Mexico?
  • These two questions have implications for Mexico, if the Lower Basin is overusing its compact apportionment, why should Mexico reduce its annual use?

The problem with the Upper Basin’s argument is that it’s based on the diversions less return flow theory. If the Lower Basin’s uses are calculated based on the stream depletion theory – the methodology the Upper Basin adopted in its own 1948 Upper Basin Compact, uses may not be greater than 8.5 maf/year.


Stream Depletion Diversions less Return Flows
Mainstem uses (a) 6.6 maf/year 6.6 maf/year
Reservoir Evaporation (b) 0.5 maf/year 0.86 maf/year
System Losses (c) 0 0.45 maf/year
Tributary Uses (d) 1.2 maf/year 2.2 maf/year
Total 8.3 maf/year 10.1 maf/year



a) Mainstem uses (deliveries from Hoover Dam) are very similar under both theories. Almost all mainstem uses are either fully consumptive or located low in the system. The average mainstem use by the Lower Division States over the last five years (2019-2023) is approximately 6.6 maf/year.

b) Under diversions less return flows the 0.86 maf/year is the average evaporation (2017-2021) from the December 2023 Reclamation study. Under the stream depletion theory, reservoir evaporation is calculated as surface evaporation less the natural losses in the inundation area that would have occurred had the reservoir not been built. This is how evaporation on Lake Powell is calculated. I estimated natural losses as .36 maf/year.

c) The 0.45 maf/year is from the December 2023 Reclamation study. Under the stream depletion theory, system losses are offset by salvaged water. As a practical matter, we have no idea how much salvaged water is currently generated on the mainstem below Hoover Dam, but we do know that the channel is much smaller today than it was before development. In 1945 during the Mexican Treaty ratification hearings, Colorado’s Royce Tipton estimated the number to be 400,000 af/year. I’ll assume they offset.

d)Under diversion less return flows, tributary uses are 2.2 maf/year, the latest data from the 2001-2005 Consumptive Uses and Losses and Report. Under the stream depletion theory, it’s reduced by 1.0 maf/year, the estimated salvage on the Gila River from the 1947 study. Because of climate change, losses today may be greater, but no data are available.

Thus, using the diversions less return flows theory, the Lower Basin is clearly using more than 8.5 maf/year, but under Upper Basin’s own stream depletion theory, it is not. Since the 1922 Compact neither defines nor prescribes a way to measure “beneficial consumptive use,” the basic question – “is the Lower Basin overusing its compact apportionment?” simply cannot be answered.

These disputes also point to the fundamental flaw with the states’ talking point that the 1922 Compact, the 1948 Upper Basin Compact, and the Mexican Treaty will serve as the foundation of the post-2026 operating rules. There is no agreement on what they say or mean. As the states continue their discussions with the goal of agreeing on a state proposal, they need to consider addressing the disputed compact issues in a straight-forward manner. Leaving these critical uncertainties for future generations to handle (like we have in the past) is no longer possible and asking the Supreme Court for a resolution will likely make matters worse, not better.










Trash day: mundane, yet remarkable

A city street, lined with trash cans, as seen from a mountain.

Note the trash cans.

Coming back from a morning hike in the Sandia Mountains above Albuquerque, I rounded a bend to see the scene above.

Note the trash cans lining the street. It is mundane, yet remarkable precisely because of how unremarkable it is. A large community of people has somehow come together, to act collectively, to get rid  of trash. This collective action, the getting-rid-of-trash stuff, depends on the broader collective action of building streets. It also requires a common shared understanding: “In my neighborhood, Monday is trash day.” Which rests on an even broader collective shared understanding – the notion of “Monday”, of a calendar.

The layers of such shared collective actions in this picture go on and on – the power lines running down the foothills behind me as I took he picture, the big water tanks and underground plumbing, the flood control dams at the mouths of each arroyo that allowed those houses to be there without being washed away.

Cities are amazing things, all the more so because of how mundane it all seems.

Opening the gates on the 2024 irrigation season in New Mexico’s Middle Rio Grande Valley

Irrigation ditch flanked by bare dirt roads and trees with no leaves. A small amount of brown water in the ditch.

First water in the Duranes Lateral, Albuquerque, New Mexico, March 2023

The Middle Rio Grande Conservancy District’s crews will usher the first water into the ditches of New Mexico’s middle valley Feb. 26, district Water Distribution Division Manager Matt Martinez told the district’s board at yesterday afternoon’s meeting.

The early water doesn’t go to irrigators right away. It’s needed to “charge” the system, wetting earthen ditches closely connected to the shallow aquifer, testing out the plumbing, finding any problem spots in the distribution system before the first water is diverted to yards, gardens, and crops later in March. Think of it as the middle valley irrigation equivalent of spring training baseball’s “pitchers and catchers report.”

What’s great about the baseball metaphor is the nervous optimism found in both.

Spring training is a time of optimism, the start of a great becoming that’s going to unfold over the coming spring, summer and fall – stiff arms, leafless trees, muddy ditchbank roads, a snowpack building but not yet subject to the vicissitudes of New Mexico’s warm April winds.

Pitchers and catchers can practice their rhythms, getting the signs down, working on the new breaking ball, clearing out the tumbleweeds that accumulated over the winter.

I love first water in the valley.

No Change in Reservoir Storage … and That’s Good News

By Jack Schmidt | February 12, 2024 (cross-posted from the Center for Colorado River Studies)

Nothing really changed in Colorado River Basin reservoir storage during January 2024. That is really good news as the basin prepares for the upcoming irrigation season.

1. Total basin water storage did not significantly change during January 2024 (Fig. 1, blue line). In fact, total basin storage increased a tiny bit—34,000 af (acre feet)—and was 28.0 million af on 31 January. Conditions in the basin remain comparable to conditions in spring 2021. There is no reason so stop our efforts to conserve reservoir storage!

Figure 1

Figure 1. Graph showing total basin storage in 46 reservoirs in the Colorado River basin between 1 January 2021 and 31 January 2024 (blue line). The black arrow points to the previous time when reservoir storage was at this amount. Total storage in Lake Mead and Lake Powell for the same period is shown by the orange line. Compiled from data downloaded at https://www.usbr.gov/uc/water/hydrodata/reservoir_data/site_map.html


2. Although the total storage has not changed, storage in specific reservoirs has been adjusted. Storage in CRSP reservoirs upstream from Lake Powell, including Fontenelle (Fig 2, green line) decreased by 109,000 af and has been decreasing since mid-summer 2023. Storage in Lake Powell (Fig. 2, gold line) decreased by 303,000 af. There was no significant change in storage in other Upper Basin reservoirs (Fig. 2., black line). In contrast, storage in Lake Mead (Fig. 2, purple line) increased by 368,000 af. On 31 January, active storage in Lake Mead exceeded active storage in Lake Powell by 1.27 maf; Lake Mead held 9.41 million af and Lake Powell held 8.14 million af. Storage in Lake Mead has slowly been increasing since mid-summer 2022.


Figure 2

Figure 2. Graph showing active reservoir storage in different parts of the Colorado River basin between 1 January 2021 and 31 January 2024. The category “other Upper Basin reservoirs” includes Granby, Dillon, McPhee, Strawberry, Starvation, Nighthorse, and 30 others. The category “CRSP reservoirs upstream from Lake Powell, and Fontenelle” includes Blue Mesa, Morrow Point, Crystal, Fontenelle, Flaming Gorge, and Navajo.


3. Basin reservoir storage continues to be depleted at an unprecedented low rate in comparison to the past decade (Fig. 3), as is also the case for the combined storage of Lake Mead and Lake Powell (Fig. 4). On 31 January 2024, the amount of basin storage gained by the 2023 snowmelt runoff had been reduced by 20%.

Figure 3

Figure 3. Graph showing the rate of reduction in basin-wide reservoir storage in each of the past ten years. The reduction in storage in 2023/2024 has been at a much slower rate than in other years. Each year that plots lower than 2023 (blue line) on this graph reflects a higher rate of loss in storage than the current year.


Figure 4

Figure 4. Graph showing the rate of reduction in the combined storage in Lake Mead and Lake Powell in each of the past ten years. The reduction in storage in 2023/24 has been slower than in any other recent year. Every year plots lower than 2023 (blue line) reflecting a higher rate of loss in storage than in this year.

A dry forecast for the Colorado River Basin. A note on policy implications.

Evaporative Demand Drought Index forecast showing drying out of Colorado and Utah over the next four weeks.

The next month (February-early March-ish 2024) points to drying over the Colorado River Basin snow-making areas.

The UC Merced Evaporative Demand Drought Index (EDDI) points to drying over the Colorado River Basin over the next four weeks.

EDDI is a new experimental tool that offers potential for tracking quickly emerging drought conditions by analyzing the evaporative demand of the atmosphere. It combines how moist things are with how hot and dry the atmosphere is – how much moisture that “thirsty” atmosphere will be sucking up out of soil and plants. (More here.) I’ve started tracking it as an add-on to watching the Colorado River Basin Forecast Center’s runoff forecasts. The forecast is already “meh” (~1maf below average). EDDI suggests we should expect it to get worse.

A Compact Tripwire in the headlights

A reminder of something Erik Kuhn and I wrote about last month:

The Bureau of Reclamation’s January 2024 “Most Probable” 24-month study forecasts that annual releases from Glen Canyon Dam for both Water Years 2025 and 2026 will be 7.48 million acre-feet per year (maf). If this happens, the ten-year total flow at Lee Ferry for the 2017-2026 period will drop to about 83.0 maf, only about 500,000 acre-feet above 82.5 million acre-feet, the first 1922 Compact hydrology “tripwire.”

That line – 82.5 maf feet of Lee Ferry deliveries over a ten year period – has become a dividing line between two contending interpretations of the most important unresolved question in the century-old Colorado River Compact: How much water must the Upper Basin deliver to the Lower Basin? What happens if it doesn’t?

A plea – we need to be having a public conversation about this. The current Upper Basin-Lower Basin negotiations over the Post-Tripwire Colorado River Management Regime appear to have wandered into the Grimpen Mire:

“It’s gone!” said he. “The mire has him. Two in two days, and many more, perhaps, for they get in the way of going there in the dry weather, and never know the difference until the mire has them in its clutches. It’s a bad place, the great Grimpen Mire.”

– Arthur Conan Doyle, The Hound of the Baskervilles

We keep euphemestically calling them the “Post-2026 Guidelines”, but let’s be real about this.

We are talking here about the Post-Tripwire Colorado River Management Regime.

It could snow a lot between now and summer and bail us out again this year. But we can’t look away from the Tripwire.

The Open Guitar Case

Inkstain is reader supported.

In Colorado’s San Luis Valley, paying for the water they use

Folks in Colorado’s San Luis Valley are engaged in a bold experiment in western water management – charging farmers for the water they use. Jerd Smith explains:

A new rule approved by the area’s largest irrigation district, known as Subdistrict 1, and the Alamosa-based Rio Grande Water Conservation District, sets fees charged to pump water from a severely depleted underground aquifer at $500 an acre-foot, up from $150 an acre foot. The new program could begin as early as 2026 if the fees survive a court challenge.

The challenge in the valley is that, with climate change inexorably chomping at the Rio Grande, and the groundwater used to replace the river’s dwindling irrigation supplies, there simply isn’t enough water to keep farming all the acreage they’ve got up there.

The valley is operating under the same two constraints that we see up and down the river – less water flowing in, and requirements established in the Rio Grande Compact to pass some of what does come in to folks downstream – Colorado can’t use it all, but must pass some water along to water users in central New Mexico. Those of us in central New Mexico’s “Middle Rio Grande” (the stretch from Cochiti through Albuquerque to Socorro) get to use some, but must pass some of on to farmers in Southern New Mexico. Under the deal now pending before the U.S. Supreme Court, the southern New Mexican’s (the Elephant Butte Irrigation District and Las Cruces area) must then pass some water across the border to people in Texas and Mexico.

Paying to Reduce Use: Private v. Public Goods

In each of those stretches – Colorado, central New Mexico, and southern New Mexico – we face the challenge of reducing use in order to meet downstream obligations.

In New Mexico, our approach to problems like this has been to treat the water as a private good, and pay its users to not use the water. This year, for example, a pipeline of money from the federal government, through the state, to our local water agency, the Middle Rio Grande Conservancy District, is paying irrigators $700 an acre to not irrigate.

The approach in the San Luis Valley is different. There, farmers who want to pump groundwater (recognizing that groundwater and surface water are an interconnected part of a single system, and that as river flow declines farmers have been pumping groundwater to replace it) have to pay for it. If you want to pump more, you have to pay more. And as it gets scarcer, the price needs to go up.

The legal terminology involving the notion of property rights here is tricky, but as a practical matter this suggests two very different approaches. In New Mexico, we are treating the water as the irrigators property, and paying them to forego its use. In Colorado, they’re treating it as public property, and requiring them to pay if they want to use it.

The Coasian Solution

Students of the Berrens-Fleck Lab will recognize this as a version of the classic problem of assigning the property right, as laid out by Ronald Coase in his classic 1960 paper The Problem of Social Cost. Overuse of water in a climate change-constrained system is a classic “externality” – a burden pushed off onto others, rather than the people who get to benefit from the use of water.

Coase’s answer – “assign the property right!” – has made his paper one of the most-cited papers in the history of papers, and won him a Nobel prize. Coase’s argument is that by assigning the property right, and starting from that point to figure out who pays and how much to solve the problem, we can converge on solutions. You can either make the people being harmed pay to stop the harm, or the people causing the harm pay to stop the harm.

We can, for example, require the factory polluting our river pay the cost of installing pollution control equipment. Or we can make the folks downstream, or the community as a whole, pay. Either way will work. The question of which approach we take is an ethical and political question.

Colorado has chosen (or at least is trying to chose – this’ll end up in court) one approach. New Mexico has chosen another.

Cartoon Coase

This is a cartoon of Coase’s argument. In the paper (which is a terrific read) he’s making a more nuanced argument involving transaction costs. In both the New Mexico and Colorado cases, the cost of setting up the payment system makes actually carrying out the policies we need super hard. But the cartoon helps frame our approach to western water management challenges more broadly.

A container ship in a southwestern desert river.

This image is fake. There also is no Large Container Ships Full of Money Act. I made that up too. It’s really the “Build Inflation Better Act” or something, I can never get that right.

The Colorado example – charge more to use water! – is rare. In the Lower Colorado River right now, we’re paying farmers, through their agricultural districts, giant container ships full of money to reduce their use – the New Mexico approach. We’re treating the water as their property, and paying them not to use it. This is an ethical and political (and possible legal?) choice.

But the key difference between the New Mexico/Lower Colorado approach and the classic Coasian cartoon is who’s doing the paying. In both cases, at least for now, we’re using Other People’s Money (OPM), via the recently passed Large Container Ships Full of Money Act (LCSFMA). Those of us in the West have somehow worked a racket where folks in Maine and Georgia and elsewhere are paying to bail us out of our mess. (To be fair, I’m sure we’re bailing them out in some way too.)

The processes by which we have to figure out how to move all this money and water around – to pay people to not use water, or to charge them for the water they use – are a great example of the power of the deeper insights in Coase’s 1960 paper. Working out the ways things don’t match up to Cartoon Coase is where the real value of the intellectual framework is found.

Sources and Methods

Two huge thanks. First, to Daniel Rothberg, whose Western Water Notes alerted me to the issue. And to Jerd Smith and the Colorado Sun, for supporting and publishing the great water journalism we all need to understand these issues. If you can, I’d encourage you to contribute to one or the other or both, to support the fundamental underlying knowledge base we all need to move forward on climate change and western water issues.

The Magic of Alleys

A blue and red touring bicycle with bags attached to the frame and handlebars is parked against a wooden post in an urban setting. The area is strewn with dry leaves and some litter on the ground. There's a chain-link fence in the background with a concrete post beside the bike. The setting appears to be a neglected urban corner with no people in sight.

A tiny alley, connecting two larger alleys. Old Town Albuquerque, New Mexico

The secret corridor proves an amazing fast shortcut to any explorer determined to brush aside low-hanging branches and to risk broken glass and rusted wire. And it offers the probing and poking explorer another view of the chrome-and-glitter commercial strip, even of the regional mall, for it makes clear the stealth with which change comes.

– John Stilgoe, in his book Outside Lies Magic

Off the western edge of Albuquerque’s historic “Old Town”, the plaza settled in the early 1700s, runs an over-named street called “Hollywood Avenue.” It’s not clear when it acquired the name, but it was an unnamed street by the time modern mapping created the legibility necessary to draw property lines so early 20th century governments could tax people to pay for roads, schools, and water management.

Soto Avenue came later, running behind the strip mall along Route 66.

“Avenue” seems a bit grandiose as a naming convention. Both feel like alleys. Hollywood especially is a favorite bike route for detouring around one of those stretches of road urban cyclists will nod about, knowingly – places built for cars that cyclists need to detour around.

But the best bit is the little cut-through between them. Perhaps 50 feet long, accessible only to pedestrians and bicycles, a square wooden bollard on either end. My bike in the picture above is parked a the Soto (south) end.

Bollards are always a clue. Look for the bollards, and when you see them, go that way.


Senate hearing next week on Tribal access to clean water: it takes more than just a pile of money

The U.S. Senate Indian Affairs Committee is holding an important hearing Thursday on S. 2385, a bill to refine the tools needed to help Tribal communities gain access to something that most non-Indian communities in the western United States have long taken for granted: federally subsidized systems to deliver safe, clean drinking water to our homes.

Inkstain readers should find these numbers familiar:

  • 48 percent of households on Native American reservations don’t have the sort of basic plumbing we all mostly take for granted – piped (and clean!) water into our houses, sanitation systems to take away waste
  • Per the Universal Access to clean water for Tribal Communities project, “Native American homes are 19 times more likely than white households to lack indoor plumbing.”

The Bipartisan Infrastructure Law and the Inflation Reduction Act allocated a lot of money to fix this stuff, but as is so often the case with large government investment efforts, there remain capacity issues associated with getting the money effectively spent. As the Universal Access folks explain:

While groundbreaking and long overdue, the funding now available for construction and repair of domestic water systems in Indian country is not a complete solution. Technical assistance is urgently needed to allow Tribes to plan and design the systems necessary to remedy the longstanding problem of lack of access to clean drinking water and bring those plans to the “shovel ready” stage where they can take advantage of available construction funding. In addition, Tribes need support to develop the managerial, financial, and regulatory capacity necessary for a fully functional and self-sustaining utility. Construction funding is not currently available to connect essential community facilities, like schools and clinics, to centralized water and sanitation, and this support is absolutely necessary to support a basic level of Tribal economic development. Finally, because Tribes cannot rely on the same types and volumes of revenue streams to support operation and maintenance of water systems, initial and temporary O&M assistance helps to ensure that the benefits of the historic investment in infrastructure are fully realized.

This is the sort of bill (there’s a companion on the House side) that makes a huge amount of sense, but could easily get sidetracked in the chaos of Congress. The ideal path is for the crucial vetting to happen in a process such as Thursday’s hearing, and then to attach it to one of those omnibus things that Congress uses these days to get non-controversial stuff done.

Clean water for Native communities should pretty clearly be non-controversial.

Rio Grande flow at Otowi in decline, fancy graph edition

Graph showing decline in Rio Grande flow at Otowi comparing 1980-2000 to 2001 to present. It has gone down.

Changing Rio Grande flow at Otowi over time

I’ve been updating the crufty old code I use to generate graphs to help me (and colleagues) think about river flows.

This one’s a little busy, so maybe for specific nerd colleagues’ use, and not general consumption?

It’s based on a request from a friend who uses these, and asked for a visualization of the wet 1981-2000 period compared to the drier 21st century. This is an important comparison given that a whole bunch of New Mexicans (including me!) moved here in the wet 1980s and ’90s, which created a sense of what’s “normal.”

It’s important to note that this is not a measure of climate, at least not directly. This is a measure of how much actual water flows past the Otowi gage, which is a product of:

  • climate-driven hydrology adding water
  • trans-basin diversions adding water (“trans basin diversion” singular, I guess, the San-Juan Chama Project)
  • upstream water use subtracting water
  • reservoir management decisions moving water around in time (sometimes reducing the flow by storing, sometimes increasing it by releasing)

I get so much out of staring at these graphs. A few bits from this one, which I did a few evenings ago curled up with my laptop in my comfy chair:

  • Look at the curves around Nov. 1 – a drop as irrigation season ends, following by a rise as managers move compact compliance water down the river to Elephant Butte. Makes me curious about what they were doing back in the ’80s and ’90s in November.
  • This year’s winter base flow is low.

At some point soon I’ll get the updated code onto Github, but it’s not quite ready for sharing. (I’m rewriting it in Python, because learning is fun!)

Thanks to the supporters of Inkstain’s crazy busking business model.