I write a book only because I still don’t know what to think about this thing I want so much to think about, so that the book transforms me and transforms what I think.
The socioeconomics of jogging
Poor folk don’t jog?
The reflection of socioeconomics in Strava’s running heat map for my town is striking. It’s sort of Tiebout sorting?
The search for enduring solutions on the Colorado River
Kathryn Sorensen & Sarah Porter, Kyl Center for Water Policy, Morrison Institute for
Public Policy, Arizona State University; John Fleck, Utton Transboundary Resources
Center, University of New Mexico School of Law
Colorado River Basin governance is increasingly struggling with a deep question in water management: When we reduce our use of water, who gets the savings?
If I install more efficient irrigation equipment, should I get credit for the saved water to expand my acreage, or save the water in an upstream reservoir as a hedge against next year’s drought? If I tear out lawns, can I use the saved water to help build the next subdivision, or save the water in an upstream reservoir as a hedge against that next year of drought?
Or should the savings contribute, not to my own resilience and well-being, but to the resilience and the well-being of the system as a whole by simply reducing overall water use?
In a deeply insightful 2013 book, British scholar Bruce Lankford bestowed the unfortunately wonky name of “the paracommons” to this question, and it dogs water policy management around the world.
This issue has been lurking in Colorado River management for a long time. Should we create legal structures that allow users to bank the savings for their own use later? Or should the reductions benefit the health of the system as a whole? There are advantages and disadvantages to both approaches, and we need to design new rules for managing the Colorado River with our eyes open on this question.
Assigned Water
In a new paper, we explore the implications of the two paths for the management of a post-2026 Colorado River.
One is to incentivize conservation by giving water users the chance to bank saved water for later use. Known most commonly as Intentionally Created Surplus (ICS), and more broadly in a series of increasingly creative implementations as “Assigned Water,” this creates short term savings.
The other involves permanent reductions – “System Water.” Water use is reduced for the benefit of the Colorado River as a whole.
In more than a decade of experimentation with these policy tools, we have seen the results. Investment in Assigned Water, attractive to water managers because of the allure of getting their water back, has crowded out investment in the more durable System Water reductions that will be needed to bring the Colorado River into balance.
As we develop new operating rules for the river, we need to be mindful of the differences involved.
Assigned Water does not solve the problem of overallocation because when it is deployed we are borrowing against our own bank. Enduring solutions on the river can only be found by addressing overallocation.
- Assigned Water creates critically important operational flexibility; it allows its owner to either forgo water deliveries in one year—or pay someone else to—and take delivery of that water during another potentially desperate time.
- Assigned Water is generally insulated from shortage, forfeiture and abandonment.
- Protection from shortage and forfeiture has value; Assigned Water creates individual resilience for its owner. Because of this, the availability of Assigned Water appears to crowd out investment in collective resilience in the form of System Water.
- In conversations about post-2026 operations negotiators are contemplating extending, enlarging and/or enhancing Assigned Water and/or creating an operationally neutral form called Top Water. In any form, Assigned Water lives outside of the existing priority system. In this regard, the conversation involves the reallocation of water in Lakes Powell and Mead.
Critics of the West’s priority system of water delivery can rejoice—nearly 40% of the water in Mead in 2023 was Assigned Water, meaning that Assigned Water is replacing priority to a significant degree. But is the priority system like capitalism in that it has its warts but the alternatives are far worse? As the expansion of the rights of municipal water providers, irrigation districts, foreign nations and tribes to own even more and different kinds of Assigned Water is contemplated for a post-2026 world, consideration should also be given to how these changes may also inure to the benefit of environmental non-governmental organizations, hedge funds and water speculators. Those who share John Wesley Powell’s fears will understand the implications because the expansion of Assigned Water in Lakes Powell and Mead may bring about the ultimate divorce of priority-based water rights from arid lands in the Colorado River Basin.
There are important elements of transparency and fairness at play. The large, powerful players on the River received Assigned Water through negotiations not available to others—meaning, there was no open bidding process or invitation to smaller entities to acquire this valuable water. Apparently, there still isn’t. Thought ought to be given to those other stakeholders—smaller cities, farmers, tribes and others—who have made investments and built economies based on the priority system. Imagine a restaurant that operates on a first-come-first-serve basis and a hungry patron who waits patiently in line for the doors to open only to be told that the rules changed while he was waiting and all of the reservations have been claimed through a process from which he was excluded.
It is helpful to continue to deploy a tool as flexible and alluring as Assigned Water, particularly in the form of operationally neutral Top Storage, so there’s no need to throw the baby out with the bath water. A reasonable path forward may be to allow the creation of Top Storage with appropriate guardrails while including a 50% cut for System Water. Post 2026, Assigned Water will be so valuable that entities likely will be willing to take a big haircut to get it, and such a required contribution solves the problem of developing enduring funding for System Water to a significant degree. Maybe ultimately environmental non-governmental organizations, hedge funds and water speculators get a piece, but if so, it will be at the price of protecting and respecting the priority system upon which so many depend.
Finding Albuquerque’s Northeast Passage
The Griegos Lateral, a Middle Rio Grande Conservancy District irrigation canal in Albuquerque’s North Valley. Also a lovely bike route!
I left for my Sunday morning bike ride today as early as an alarm, coffee, and breakfast would allow – to beat the heat.
To structure the route, I set myself a puzzle: to ride from Albuquerque’s Old Town, paralleling the Rio Grande to the north, all the way up the valley to the north with a minimum – ideally zero – time spent on busy streets. There’s no way to avoid crossing busy streets, which are like alligator-filled moats. And there are a couple of quite safe routes on small main roads with good bike lanes. But – my puzzle, my rules – those were off limits.
This of course would be trivial on the riverside bike trail, but, to paraphrase Yogi Berra, nobody rides that trail any more on the weekends – it’s too crowded.
I’ve ridden the north valley many dozens of times, and had a rough idea in my mind of the puzzles pieces I needed to assemble – a handful of twisty old country lanes, interconnecting ditchbanks, crucial alligator moat crossings, the critical breakfast burrito stop. But part of the fun was assembling the pieces on the fly, so I didn’t want to over plan.
A friend and I have done this on the west side of the river – we dubbed it the “Northwest Passage.” But we’ve strangely never done it on the river’s east side. So “Northeast Passage” was the goal as I set out before sunup this morning.
This is really about the book
This is, of course, a misdirection.
We got the latest round of editorial feedback last week for Ribbons of Green, the book Bob Berrens and I are writing. The feedback was useful, in particular in showing areas where the points we are trying to make did not come through with sufficient clarity.
I’m excited to dive back in, but there is this personal temporal challenge in writing a book. You spend a bunch of time writing, fully immersed, you hand it off into an editorial process, and then you go on to thinking about other things. And then the manuscript returns, months later, in need of love and attention.
Much of what I’m thinking about overlaps with the issues in the book, but writing a book, and now revising it, are full brain activities. I need to yank my brain back into Ribbons of Green.
So I spent six hours this morning riding my bike, slow AF, through our book’s landscape.
The Old High Ground
Sunup in Old Town
I hit Old Town, the plaza where one of greater Albuquerque’s villages was founded in 1706, around sunup. Like all the key human landmarks of the old landscape, it was built on slightly higher ground, a pattern that left traces that define the modern landscape in ways that show up, again and again, in the book.
The ditches and old twisty roads follow that slightly higher ground – that feature of the landscape was central to the bike riding puzzle.
Modern Albuquerque Old Town is a wonderful combination of cheesy tourist fluff and community center. The San Felipe de Neri Catholic Church was built on its current site on the plaza’s north side in 1793, but the parish dates to the village’s founding in 1706. As I rode through the center of the plaza, people were converging for early mass. It’s still a working church.
A couple of alleys to the west led me to Gabaldon Road, which turns north at what was once the edge of the river’s flood plain. The Rio Grande’s main channel, pinned between levees, is now nearly half a mile to the west, and this part of former flood plain is filled with houses. The road passes what was once Palmer’s Slough, where city kids in the early 20th century would go swimmin’, and sometimes drownin’, until they filled it in because of pestilence and whatnot and built houses on top of it.
Gabaldon met my “country lane” puzzle rule, but the Duranes ditch, which for over 300 years has been spreading water across the flood plain for human use, was even better. It jogs north through a modern subdivision called Thomas Village, built on an old swamp. Modern subdivisions are often built atop old swamps, land that was available as the swamps were drained.
The Duranes does significant work in our narrative – a centuries-old irrigation ditch that serves as a modern urban amenity, irrigating a bit, and shading the ditch walkers. And bicyclists!
Guadalupe Trail
After a couple of ditchbank miles to the heading of the Duranes, I switched over to the Griegos Lateral (“before 1800” in my 19th century guide to the ditches of Albuquerque) until I hit one of the modern drains. “Modern” is a relative term here. In a landscape threaded with ditches dating to the 1700s, the Griegos Drain is a youngster at 90-plus years old. The drains were crucial to the making of modern Albuquerque, lowering the water table and allowing a city to emerge from the swamps.
The drains are also crucial to low-stress cycling, with big wide service roads. They’re not always rideable – they can get sandy, and drainside riding can lead to a good deal of walk-a-bike through the sandiest bits. And they’re mostly not nearly as shady as the irrigation ditches. But the Griegos Drain is special to Bob and I, because it’s where we first dug down into the old maps in detail to understand the relationship between the old swamps and the modern city. Crossing the alligator moat at Montaño Boulevard, I followed the ditchbank past what was labeled a “lake” in the 1920s map, a swampy piece of land owned by Melquiades Montaño now home to a city-owned expanse of farmland.
With the water table lowered by more than a half century of urban groundwater pumping, the drain doesn’t have a lot to do these days, and its northern reaches have been abandoned, so I jogged east to a lovely street called Guadalupe Trail. It’s one of the old ones, twisting and starting and stopping, pavement laid down on an old wagon route through the North Valley. When I first started riding in Albuquerque a quarter century ago, a friend gifted me Guadalupe Trail, and I’ve always treasured it.
Water in the desert.
Guadalupe Trail is home to some of Albuquerque’s most ostentatious, well-irrigated wealth. This raises questions about equity in the allocation of water under conditions of scarcity, which are a big part of what I’m thinking about lately, but which are largely beyond the scope of the book. But it’s hard to look away when you’re rolling slowly by on a bike and see the sprinklers. This sort of thing is why I assigned myself the bike ride puzzle.
Lately I’ve been taking my morning rides through some of Albuquerque’s poorest neighborhoods. They are noticeably less green, both to a dude wandering around on a bike and also to a dude who spends an inordinate amount of time poking at the satellite data to try to better understand, quantitatively, where Albuquerque’s water conservation success is most noticeable. A subject for another bike ride essay on another day. As I said, beyond the scope of the book. Pay attention to the book, John!
Brunch
The closest thing to a busy street came at the upper end of this section, where I diverted into the urban busy-car landscape for a breakfast burrito. It was still early, but breakfast burritos are key for umpty-hour bike rides. Properly packaged, they fit in a cycling jersey back pocket. Or today I was riding with a pannier. Five or so bites every few miles, and I can ride for hours.
The Albuquerque Main
I refilled the water bottles, and turned back to the Chamisal Lateral, another of the old twisty ditches that follows the high ground the rest of the way north, all the way to the Sandia Pueblo, the indigenous community on Albuquerque’s northern border. Looking back at my old bike ride GPS traces, I see a few rides on bits of the Chamisal, but I’d never ridden the whole thing, which is a shame. Now I know.
At its northern end, the Chamisal’s heading draws from the Albuquerque Main Canal, a larger canal that is mostly big and straight, built in the 1930s as the Middle Rio Grande Conservancy District’s early works were consolidating irrigation in the valley, in pursuit of the development of commercial agriculture here.
It’s the “straight” part that’s the clue to the socio-hydrologic history. The old ditches are twisty. The modern ones are straight. The old roads are twisty. The modern ones are straight. Or when they curve, it’s a planned, drafting-tool curve, not the wander of a foot path turned into a horse path turned into a wagon path turned into a street.
This is why I ride.
“Now I can ride all day!”
Albuquerque’s Aquifer
I've been
a) Playing with Datawrapper as a tool for displaying data here on Inkstain, and
b) Thinking about Albuquerque's aquifer as bad summer river flows force us back onto groundwater
(City #2, in the North Valley, is one of a quartet of groundwater monitoring wells drilled in the late '50s as Albuquerque's population and groundwater pumping began to grow. I use it for big picture attention because it's reasonably well placed to give a good rough picture of what's going on, and has a nice long time horizon.)
update:
Locator map was super easy in Datawrapper.
Tacos and a bike helmet
Tacos and a bike helmet.
The “plate of food with a bike helmet” is my favorite genre of Strava photo.
Tipping Point: Colorado River Reckoning
Lake Mead at sunup, July 24, 2024.
Out toward the top left corner of this picture – maybe a little bit left, out of the frame – is the point where the Southern Nevada Water Authority gets its water out of Lake Mead. There’s nothing to see – the intake is at the bottom of the reservoir.
Completed in 2015, with a new pump station first turned on in early 2022, the intake system represents a ~$1.5 billion investment in shoring up the reliability of the Las Vegas, NV, water supply as Lake Mead and the Colorado River decline.
I hitched a ride yesterday on SNWA’s water quality sampling boat, and they took me over to the face of “Saddle Island” (not an island any more with the reservoir this low!) to see the areas where the old intakes are. Back in 2022, one of the old intakes emerged above water. Had Las Vegas not invested in the new system, we would have faced huge risk to the water supply of a community of 2 million-plus people, and terrible choices, as Mead dropped.
I tried to peer down into the water to see the pipe, but Mead’s up high enough now that it’s no longer visible. But it’s an important place, I wanted to try to see it, which is why I hitched the boat ride. Mead here is doing double duty: water storage for Phoenix, Los Angeles, and the farm districts of the Lower Colorado, but also forebay for the pumping system for Las Vegas’s water supply. Multiple purposes.
Las Vegas spent the $1.5b not for new water, but to provide reliability for the water they’ve got. But in doing that, removing (reducing?) the risk to a city of 2 million people, Las Vegas also removed the risk that the basin as a whole would have faced if it had to chose between Las Vegas’s supply and the needs of downstream users as the reservoir’s levels dropped toward the intake pipes.
Newshour link
I’m here for today’s (July 24, 2024) PBS Newshour “Tipping Point” show. 5 p.m. Mountain Time (7 eastern, 4 Pacific), livestream link here.
Hoover Dam and the social nature of infrastructure
Hoover Dam in the fading light of a hot summer evening
A water nerd friend and I made a pilgrimage yesterday evening to Hoover Dam, spanning the Colorado River on the Arizona-Nevada border.
We’d had dinner at one of the restaurants on the docks at Hemenway Harbor, and driven up to the old abandoned boat ramp at Boulder Harbor, two Lake Mead landmarks for me, places I often visit. It was late, and hot as hell, and we were tired, but it didn’t take much persuasion for my friend to say “yes” to a last stop at Hoover Dam.
I’m here in Southern Nevada to be part of a PBS Newshour livestream Wednesday: “Tipping Point: Colorado River Reckoning.” I came out a couple of days early to see some friends and do the sort of “place-based” stuff that’s at the heart of my Colorado River work. I’ve been coming to this place – Lake Mead and Hoover Dam – for the last 15 years, watching the reservoir rise and fall, using this place as a conceptual anchor as I write my books.
My best guess based on hazy childhood memory is that I first visited Hoover Dam 60 years ago. We were on our annual summer car-camping trip, and I remember five-year-old John being both awestruck and uneasy – a bit frightened? – at the scale of the thing. Many years later, on one of many return trips, I stumbled on the thing that I remember most vividly: off the side of an embankment, massive concrete plugs that had been removed from the turbine tubes, dumped off the old rail line, lying today in a ravine.
It was a vague thing, fuzzy and just out of reach, but seeing them again on a bike ride along the Hoover Dam rail trail, the memory jumped up out of the ravine at me. As my friend remarked when I told them the story last night, I got bitten early.
Deb Chachra and the social nature of infrastructure
In an interview published last week in Public Books, the engineer Deb Chachra said a kaching thing about Hoover Dam that captures why I keep coming here, why I anchor so much of my thinking in the dam itself:
To borrow an idea from Joan Didion, who used it to describe driving in Los Angeles, these older forms of infrastructure, especially charismatic megastructures like bridges and train stations, can be secular cathedrals. We recognize that these are things that we made for ourselves and for each other. People have been visiting the Hoover Dam in droves since it was brand-new, so I don’t think it’s nostalgia per se—I think it’s more about celebrating this idea of the collective, these collective or communal projects. If we’re nostalgic, I think it’s less about the physical structures and more about the idea of working collectively.
The Boulder Canyon Project Act, carved in stone
Five years ago, on my umpty-first tour of Hoover Dam, a friend steeped in the “law of the river” led me to the elevator tower on the dam’s Nevada side to look at the decorative frieze. It’s a stone carving (or maybe cast concrete), visualizing the statutory purposes embodied in the Boulder Canyon Project Act, the act of Congress that authorized construction of the dam.
Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That for the purpose of controlling the floods, improving navigation and regulating the flow of the Colorado River, providing for storage and for the delivery of the stored waters thereof for reclamation of public lands and other beneficial uses exclusively within the United States, and for the generation of electrical energy as a means of making the project herein authorized a self-supporting and financially solvent undertaking, the Secretary of the Interior, subject to the terms of the Colorado River compact hereinafter mentioned, is hereby authorized to construct, operate, and maintain a dam and incidental works in the main stream of the Colorado River at Black Canyon or Boulder Canyon…. (emphasis added)
This is what Chachra is talking about. We often view Hoover Dam as a remarkable achievement of physical engineering, and it is. But it is, more importantly, an act of collective will. We came together in the 1920s, in community, to envision a desired future – of cities and farms in a place with too little water for either without infrastructure. We wrote a set of rules – the Colorado River Compact, the Boulder Canyon Project Act – that instantiated that collective will in the construction of a physical object – Hoover Dam.
And then we did the same thing, again and again, across the West. This enabled the places that tens of millions of us now call home.
Yesterday evening it was 110F (43C) after sunset, the parking lots were closed, and the tourists still came. My friend, who may be more of a Hoover Dam/Lake Mead/Colorado River nerd than I am (this is saying a great deal) was talking about the dam’s aesthetics – the care paid to the art deco flourishes – like the Boulder Canyon Project Act frieze. It’s a testament to the understanding of the people who built it that it was more than physical infrastructure – that it was a monument to collective action, the point Chachra so eloquently made.
This is why I’m confident, despite the current conflicts over how to share the shortages we face as a result of climate change, that we’ll figure things out. Collective action is at the heart of what we’ve been doing, it’s often hard, but we do it.
A note on Chachra’s book
Chachra’s book, How Infrastructure Works, is a terrific look at the social nature of infrastructure. Highly recommended.
The 2024 Runoff Season Comes to an End – How Did We Do?
By Jack Schmidt, Utah State University Center for Colorado River Studies
How did we do in the continuing effort to recover reservoir storage? How much reservoir storage accumulated from this year’s snowpack, and how does that accumulation compare to other years?
In Summary:
Total basin-wide reservoir storage is an appropriate metric to describe the status of the regional water supply and its year-to-year changes. Reclamation provides data on the storage contents of 46 reservoirs in the basin that are primarily managed by the Bureau of Reclamation but also by municipal water agencies and water conservancy districts. Whether destined for within-basin use or for trans-basin diversion, the total amount of water in these reservoirs is the carryover storage available to sustain use during dry times.
Accumulation of storage in those reservoirs occurred between mid-April and early July 2024, and basin-wide storage increased by 2.5 million acre feet. This amount is only 30% of the increase in storage that occurred during the same period in 2023. Nevertheless, basin-wide reservoir storage increased by 300,000 af when the summer peak of 2024 is compared with the summer peak of 2023, because consumptive uses and losses in the intervening time between the two runoff years was only 2.2 million acre feet. Despite the modest runoff of 2024, water managers were able to increase reservoir storage, because they had done such a good job of limiting consumptive uses following the 2023 runoff season.
Today, 62% of the total basin-wide storage is in Lake Mead and Lake Powell. The combined contents of these two largest reservoirs in the United States peaked on 8 July at 18.5 million af. Most of 2024’s snowmelt runoff was stored in Lake Powell, and storage in Lake Mead declined during spring and early summer 2024. Now that the runoff season has ended, some of the contents of Lake Powell will be gradually transferred to Lake Mead.
The Details:
On 6 July, storage in the Colorado River basin peaked for the year at 30.0 million acre feet (af), approximately 50% of capacity of the reservoir system1 (Fig. 1). The combined contents of Lake Mead and Lake Powell peaked on 8 July at 18.5 million af, approximately 37% of the capacity of those two reservoirs. The last time total basin reservoir storage was as much as this was in early January 2021, and the combined storage of Lake Mead and Lake Powell had last been at its present volume in very late April 2021. Thus, reservoir storage has not yet recovered to the average conditions between 2005 and 2020.
Figure 1. Graph showing reservoir storage in the Colorado River watershed between 1 January 1999 and 15 July 2024.
The season of water accumulation, when inflow to reservoirs exceeds outflow, that began in mid-April has now ended. How did we do in the continuing effort to recover reservoir storage? How much reservoir storage accumulated from this year’s snowpack, and how does that accumulation compare to other years?
The snowpack of the Upper Basin peaked on 3 April at 16.8 in of snow water equivalent (SWE)2. For comparison, the median peak SWE for the past 30 years, as computed by the Natural Resource Conservation Service, was 16.0 in., so 2024 was a pretty good year. Nevertheless, 2024 was not nearly as good a year as 2023 when the peak SWE was 23.9 in. Preliminary estimates of natural flow at Lees Ferry for Water Year 2024 are that this year’s natural flow3 will be 12.1 million af, although that estimate may change slightly by the end of the water year.
The relation between peak estimated SWE in the Upper Basin and natural flow at Lees Ferry has a reasonably good correlation for data from 2000 and the years of the 21st century (Fig. 2). There is year-to-year variation in this relation caused by springtime weather that affects the rate of melting and the amount of sublimation. Variation is also caused by the intensity of the summer North American monsoon that augments the natural flow but is unrelated to snowmelt. Estimated natural runoff in 2024 was well predicted by the general relation.
Figure 2. Graph showing the relation between peak annual snow water equivalent for the Upper Colorado River basin and natural flow at Lees Ferry, estimated by Reclamation. The solid line is an exponential relation fit to these data.4
The amount of water added to reservoir storage is very well predicted by the natural flow at Lees Ferry (Fig. 3), and this relation shows that much more of the natural runoff is captured by reservoirs in wet years than in dry years. In 2024, approximately 20% of the estimated natural flow was stored, consistent with comparable years (2010, 2014, 2015, and 2016) (Fig. 3). A higher proportion of the natural runoff was stored in the wet years of 2005, 2011, 2019, and 2023, when more than 40% of the natural runoff was captured in reservoirs. More than 30% of the natural runoff was stored in 2008, 2009, and 2017.
Figure 3. Graph showing increase in basin-wide reservoir storage as a function of natural flow at Lees Ferry. The solid line is linear relation fit to these data5.
The combined contents of Lake Mead and Lake Powell peaked on 8 July, but storage in each reservoir followed very different trajectories (Fig. 4). Lake Powell, which is upstream from Lake Mead, captured the inflowing snowmelt runoff and increased in storage by 2.2 million af between mid-April and early July while Lake Mead lost approximately 900,000 af. Now that the inflow season has ended, storage will gradually decline in Lake Powell and increase in Lake Mead.
Figure 4. Graph showing the distribution of reservoir storage in different parts of the Colorado River basin between 1 January 2021 and 15 July 2024.
The storage gains resulting from the 2024 runoff compensated for the consumption of reservoir storage that had occurred after the 2023 runoff season (Fig. 5). This year’s peak of 30.0 million af is slightly more than the peak storage in summer 2023 that was 29.7 million af. This small increase in storage occurred despite a modest 2024 runoff season, because the basin’s water managers had done a good job in conserving the gains of last year (see blog post of 21 May 2024). Only 2.2 million af was consumed or lost following the 2023 runoff season, and the gain of 2.5 million af in 2024 exceeded the preceding loss. Thus, basin-wide storage is ever so slightly better than last year, because we used so little water last year. We now begin a 9-month period when the job in front of us is to continue to reduce consumptive uses and losses until the onset of the 2025 snowmelt season. Let’s not lose focus. We’re all in this together.
Figure 5. Graph showing changes in reservoir storage between 1 January 2023 and 15 July 2024.
1. These data are for 46 reservoirs whose daily storage contents are reported by Reclamation at: https://www.usbr.gov/uc/water/hydrodata/reservoir_data/site_map.html. The data summarized here are through 15 July.
2. Natural Resources Conservation Service. Snow water equivalent data accessed at: https://nwcc-apps.sc.egov.usda.gov/awdb/basin-plots/POR/WTEQ/assocHUC2/14_Upper_Colorado_Region.html.
3. Bureau of Reclamation. Natural flow data accessed at: https://www.usbr.gov/lc/region/g4000/NaturalFlow/provisional.html. Lees Ferry data were released on 22 April and are provisional and based on the April 24-month study. This estimate will be revised in August.
4. This relation is y = 4,048,600 * e(0.06632 x) , where y is the annual natural flow at Lees Ferry for the water year, in acre feet, and x is the peak snow water equivalent of the year, in inches. The R2 of this relation is 0.73.
5. This relation is y = -6,484,000 + 0.75833 X , where X is the annual natural flow at Lees Ferry for the water year, in acre feet, and y is the increase in basin-wide reservoir storage that occurred during the snowmelt season typically between mid-April and mid-July . The R2 of this relation is 0.92. Data used to calculate this relation do not include 2002 and 2012 when basin-wide storage decreased during the snowmelt season.
2. Natural Resources Conservation Service. Snow water equivalent data accessed at: https://nwcc-apps.sc.egov.usda.gov/awdb/basin-plots/POR/WTEQ/assocHUC2/14_Upper_Colorado_Region.html.
3. Bureau of Reclamation. Natural flow data accessed at: https://www.usbr.gov/lc/region/g4000/NaturalFlow/provisional.html. Lees Ferry data were released on 22 April and are provisional and based on the April 24-month study. This estimate will be revised in August.
4. This relation is y = 4,048,600 * e(0.06632 x) , where y is the annual natural flow at Lees Ferry for the water year, in acre feet, and x is the peak snow water equivalent of the year, in inches. The R2 of this relation is 0.73.
5. This relation is y = -6,484,000 + 0.75833 X , where X is the annual natural flow at Lees Ferry for the water year, in acre feet, and y is the increase in basin-wide reservoir storage that occurred during the snowmelt season typically between mid-April and mid-July . The R2 of this relation is 0.92. Data used to calculate this relation do not include 2002 and 2012 when basin-wide storage decreased during the snowmelt season.
We encourage the use of these figures in your own work with appropriate credit (Jack Schmidt, Center for Colorado River Studies). Please contact us if higher resolution images are required.
Colorado River 2023 Water Use: An Optimistic Narrative
Lower Basin U.S. use
Preparing for A Thing I’m doing next week, I updated the Crazy Fleck Spreadsheet this morning of data from Reclamation’s annual Lower Basin decree accounting reports.
Amid all the angst and rhetoric, it is easy to miss the salient fact made clear by this graph: Lower Basin water users have reduced their take on the Colorado River substantially since the early 2000s.
- Nevada’s use was the lowest since 1992.
- Arizona’s use was the lowest since 1991.
- Records that far back in time are tricky*, but California’s take on the river in 2023 was appears to have been the lowest since the late 1940s.
To be clear, the use in the late 1990s and early 2000s was unsustainably large. Praise is due for shrinking Lower Basin use, but the praise should be tempered by the fact that that they didn’t do it until the reservoirs had dropped to scary low levels.
But – crucially – everyone’s economy is doing fine. We’ve absorbed dramatic water use reductions without harming the basic structure and function of the Lower Colorado River Basin communities that depend on the river.
Upper Basin Data
Upper Basin water use
Working with Upper Basin data is trickier*. There’s a new dataset from Reclamation that uses remote sensing to estimate consumptive use from 1971 to 2023. There’s been a good deal of back-and-forth among Colorado River data nerds because of some confusing aspects of the data, which we hope to sort out soon to enable a more useful analysis. But the top line numbers tell a different but also ultimately an optimistic story.
The curve appears (see data nerd confusion caveat above) to show an upward trend since the 1970s with a huge amount of interannual variability. So we haven’t hit the conservation brakes yet, at least at the basin scale. But it also is clear that the Upper Basin is using far less than the 7.5 million acre feet tagged for us in the 1922 Colorado River Compact.
We Can Do This
It is easy to get tangled these days in the anger and finger pointing about who should cut, and by how much, about who has already cut and how and why, about questions that are both technical but more importantly deeply emotional about equity and fairness. We need to remember and learn from our successes.
* A Note on Data
The Lower Basin data from 1964 to the present is contained in the decree accounting reports, prepared by the Bureau of Reclamation since the Supreme Court ruling in the Arizona v. California case back in the 1960s. Prior to that, I have stitched in a dataset created by the numbers wizards at the Metropolitan Water District of Southern California.
The Upper Basin data comes from the new Upper Basin Consumptive Uses and Losses reports published by the Bureau of Reclamation. The were originally published in May, then a revised set was published in June, I’m cautious in my analysis and citation because there are still some things I don’t understand about them.