Half 2 of The Colorado River Story.
Within the first piece I instructed you Lake Powell is sitting about 34 toes above the road the place Glen Canyon Dam stops making energy. This one’s about what’s beneath that line, as a result of that’s the place the story will get genuinely dangerous, and it’s the half virtually no one outdoors a handful of water nerds and environmental teams is definitely speaking about.
Brief model: the dam has a backup approach to move water downstream as soon as the lake will get too low to run the generators. That backup was by no means constructed to run full-time. After they examined it a pair years again, it began chewing itself up. And the federal government’s personal engineers wrote the issue down in a memo that principally no one has learn.
Let me stroll you thru it, as a result of when you perceive how this factor works you’ll by no means take a look at a “Lake Powell hits useless pool” headline the identical method once more.
There Are Two “Lifeless” Traces, Not One
Most headlines toss round “useless pool” prefer it’s a single cliff you drive off. It isn’t. There are two totally different important ranges at Glen Canyon Dam, and mixing them up is how folks both freak out concerning the incorrect factor or blow the entire thing off.
The primary line is minimal energy pool, 3,490 toes. That’s the extent the place the water sitting over the dam’s energy intakes, the penstocks, will get too shallow to run the generators safely. When the water above these intakes drops too low, they begin pulling air down together with the water, similar because the little whirlpool that spins up when your sink drains. That air will get dragged into the generators and types bubbles, and when the bubbles collapse they hit with sufficient drive to punch pits into metal. That’s cavitation, and it’ll wreck a turbine in a rush. So at 3,490 the eight mills should shut off. No extra hydropower. We’re about 34 toes above that proper now.
The second line is true useless pool, 3,370 toes, one other 120 toes down. That’s the elevation of the final holes within the dam that may move water by gravity, the river outlet works. Drop under 3,370 and the floor of the lake sits underneath each outlet within the construction. Nothing goes downstream by itself after that. The river, for all sensible functions, stops passing by means of the dam. We’re about 154 toes above that one.
So right here’s how the degrees stack up:
Have a look at that hole between 3,490 and three,370. In that 120-foot band the generators are useless and the one approach to get water out of Lake Powell and right down to Arizona, Nevada, California, and Mexico is these outlet works. That band is the entire ballgame, and that’s precisely the place the difficulty lives.
The Backup Pipes
The river outlet works, all people calls them the ROWs, are 4 metal pipes, every 8 toes throughout, fed by two intakes within the again face of the dam. Vast open, all 4 collectively can transfer about 15,000 cubic toes of water per second.
They had been constructed as a backup. A job participant, not the starter. Their entire job was quick stuff: flood-control releases when the reservoir received too full, the occasional experimental “excessive stream” burst to push sediment down into the Grand Canyon, and shifting water when the powerplant was offline for a stretch. Fast jobs, then again to sleep.
That sediment job is value a second, as a result of it’s a part of why this dam is such a headache. The Colorado carries a staggering load of silt, and Glen Canyon Dam stops it chilly, so all that sediment piles up within the backside of Lake Powell as a substitute of rolling on down by means of the Grand Canyon prefer it did for hundreds of thousands of years. Down within the canyon, the seashores and sandbars that fish and native habitat and river-runners depend upon slowly wash away with nothing to switch them. So each few years Reclamation runs an enormous deliberate launch, a Excessive Circulation Experiment, to kick some sediment downstream and rebuild these seashores. It’s one of many few instances they really open up the outlet works and run actual water by means of them. Maintain that in thoughts, as a result of it’s how we discovered the pipes have an issue.
What the ROWs had been by no means designed to do is run repeatedly, year-round, for months or years on finish as the only real approach to maintain water flowing to 30-some million folks downstream. No person drawing up this dam within the Fifties figured we’d ever be dry sufficient, or caught sufficient, to lean on these pipes as the principle occasion. However that’s precisely the nook the drought is backing us into.
And there are two separate issues with relying on them, which the environmental teams have been yelling about for years.
One is simply dimension. Fifteen thousand cubic toes per second appears like loads till you bear in mind the decrease states plus Mexico are owed someplace round 9 million acre-feet a 12 months. Cramming that whole supply by means of 4 backup pipes is a decent slot in one of the best case, and it will get worse because the lake drops, as a result of a decrease reservoir means much less stress pushing the water by means of. Reclamation has even stated the outlet works could also be functionally ineffective someplace round elevation 3,394, which is above the precise 3,370 useless pool mark. That means the river might successfully give up passing usable water earlier than the lake ever technically hits the quantity all people factors at.
The second downside is the one that ought to actually seize you.
They Ran the Backup, and It Began Consuming Itself
In April 2023, Reclamation put the outlet works to actual use. They ran a type of Excessive Circulation Experiments, pushing round 3,500 cubic toes per second by means of the pipes for about 72 hours to maneuver sediment and rebuild sandbars down within the Grand Canyon. Nothing unique on paper.
After they went in and inspected afterward, they discovered cavitation harm contained in the pipes. The identical bubble-implosion course of that threatens the generators had began pitting and eroding the metal and the protecting coating contained in the outlet works themselves. And right here’s the ugly twist: the physics will get worse the decrease the lake drops. So the precise circumstances the place you’d be compelled to depend on these pipes are the precise circumstances the place they’re most probably to tear up.
This isn’t even the primary time. Cavitation and coating harm within the outlet works was first noticed method again in 1965, after a launch just a little larger than the 2023 one, and it’s proven up on and off ever since. So there’s a 60-year paper path on these pipes being sensitive underneath heavy sustained stream, and we’re now severely discussing working them broad open indefinitely.
Reclamation’s repair to this point has been to line the insides with epoxy, a short lived patch that took months, and so they’ve scheduled extra relining work since. Additionally they constructed a few small-scale bodily fashions of the dam at their Technical Service Heart in Denver, precise scale replicas, to allow them to run water by means of them and watch how the construction behaves at low reservoir ranges with out wrecking the actual factor to seek out out. On high of all that they put out momentary working pointers whose whole objective is to maintain Lake Powell above 3,490 toes in order that they by no means should depend upon the outlet works within the first place.
Their present working plan is principally constructed round not having to make use of the backup in any respect. That ought to inform you precisely how a lot confidence they’ve in it.
The Memo they Tried to Disguise
In March 2024, Richard LaFond, the director of Reclamation’s Technical Service Heart, put the issue in writing in a technical memo. It’s a dry doc. It’s about metal pipes and coatings and discharge charges and upkeep schedules. It’s additionally, quietly, one of many extra essential issues any federal engineer has written about this river in years, as a result of it’s the federal government admitting on paper what the skin critics had been saying all alongside: the outlet works shouldn’t be relied on as the only real technique of sustained water supply, and working them long-term drives up upkeep and raises actual operational and security considerations.
Plain English: our backup plumbing degrades once we really lean on it, and we all know it.
Eric Balken, who runs the Glen Canyon Institute, has been about as blunt as anyone. His level is that even when all people dropped all the pieces at this time and dedicated to a real repair, like constructing a bypass that routes water across the dam at river degree, that answer nonetheless takes one thing like ten years to design and construct. So yearly we spend arguing as a substitute of constructing is a 12 months we flat-out don’t get again. If the reply takes a decade both method, he’s requested, why are we nonetheless procrastinating?
The bypass concept, pushed by teams just like the Utah Rivers Council, is precisely what it appears like: a tunnel or channel that lets the Colorado stream round Glen Canyon Dam close to river degree, so water supply now not is dependent upon the dam’s getting older outlet plumbing in any respect. It’s the form of factor that will really clear up the issue. It’s additionally costly, gradual, and politically radioactive, as a result of to some folks it seems to be like step one towards giving up on the dam solely. So it sits there, mentioned and undone.
And the Glen Canyon Institute’s worst-case learn is the one which sticks with me. Their argument isn’t simply that the pipes are too small. It’s that the low-water physics might harm the shops badly sufficient to make them unusable, and if that occurred on the incorrect second, there is likely to be no managed approach to launch water downstream in any respect. Not “much less water.” No good approach to ship it. That’s the factor sitting on the very backside of this entire story.
What This Is, and What It Isn’t
I’m not going to promote you a Hollywood dam-burst, as a result of it isn’t that, and anyone telling you Glen Canyon is about to crack open and wash Arizona off the map is both mendacity or doesn’t perceive the issue. Even the Sierra Membership, which is not any fan of this dam, has stated there’s no structural threat to the dam itself. It’s a large plug of concrete and it’ll maintain standing there whether or not there’s water behind it or not.
The hazard isn’t the dam falling down. It’s shedding management of the water going by means of it. And for the 30-plus million folks on the finish of the pipe, these two issues find yourself feeling like the identical day. Whether or not the river stops as a result of the concrete failed or as a result of the one working outlet received too chewed as much as run safely, the water nonetheless doesn’t present up on the canal. It’d be some boring engineering no one outdoors Denver might clarify, and the end result would nonetheless be dry ditches working by means of Phoenix.
There’s additionally an actual probability this by no means involves a head, and I’ll say that simply as plainly. The states have been holding the lake up on objective, parking water in Powell as a substitute of releasing it, draining smaller reservoirs upstream to maintain the extent propped. So long as they will maintain Powell above 3,490, the outlet works keep a backup no one has to truly belief. The whole recreation proper now just isn’t dropping into that 120-foot hazard band within the first place. However that’s shopping for time in opposition to a river that retains shrinking, and one dangerous winter can burn by means of the cushion quick.
The Half That Ought to Really Make You Mad
Right here’s the political shitshow. All that post-2026 rulemaking I lined in Half 1, the enormous federal course of deciding how the entire river will get run after this 12 months? Reclamation has stated flat out that it’s “not an infrastructure EIS.” Translation: the method rewriting the foundations for all the river is particularly not taking a look at fixing the dam’s plumbing. They drew a field across the infrastructure downside and set it off to the aspect.
In the meantime the Decrease Basin states, those whose water actually comes by means of these pipes, have straight-up instructed Inside to check an overhaul of Glen Canyon Dam. Environmental teams have been asking for a similar factor for years, at conferences, within the press, in direct letters to the company. And the repair that will really settle it, some model of that river-level bypass, is a ten-year construct no one has dedicated to beginning.
So put all of it collectively. A recognized downside with a paper path again to 1965. A 2023 take a look at that proved the harm is actual and present. A 2024 memo the place the federal government admits it in writing. Outdoors teams and downstream states all pointing on the similar factor. And the official transfer is to maintain the repair out of the principle planning course of and wager that the lake stays excessive sufficient that we by no means have to seek out out what occurs down in that hazard band. None of that’s an accident of engineering. It’s a call to look away from the costly downside and hope the climate cooperates.
What This Means For You
I’m not going to redo the entire water-prep rundown from Half 1 right here, however the plumbing angle modifications one factor value spelling out.
Most individuals image the water disaster as a gradual, orderly factor. Lake will get low, cuts get introduced on the information, all people grumbles and rations, life goes on. The outlet works downside is the explanation it may not play out that clear. If Powell drops into that hazard band and the pipes begin appearing up, deliveries might get throttled or interrupted for emergency repairs on infrastructure that’s underwater and underneath stress, and that form of interruption doesn’t ship you a well mannered 90-day discover. That’s the distinction between a scarcity you watch coming for months and a supply hiccup that lands on some random Tuesday.
Which is the entire cause I maintain beating the identical drum. Retailer actual water and sufficient of it, a minimum of a gallon and a half per particular person per day, two weeks minimal and a month in the event you can handle it, in food-grade containers you really rotate. Full walkthrough’s right here: Lengthy-Time period Water Storage. And the facility dies earlier than the water does, so again that up too: Low cost Off-Grid Energy: Actual Photo voltaic Setups Below $1,000. The purpose of prepping these items is so a foul Tuesday is an annoyance as a substitute of an emergency.
The place This Goes Subsequent
In order that’s the dam. Two useless strains, a 120-foot hazard band, a set of backup pipes that had been by no means constructed for the job and began coming aside the one time we actually used them, a memo the place the feds admit it, and a repair no one’s began that takes ten years irrespective of after they start.
Subsequent in The Colorado River Story I’m entering into the battle I flagged in Half 1: the higher states versus the decrease states, and the authorized knot beneath the entire thing. Who’s really required to surrender water when there isn’t sufficient, why the 1922 deal makes that nearly inconceivable to reply, and what occurs when the feds give up ready for a handshake and simply impose a solution. That’s the place this stops being about engineering and begins being about who wins and who dries up.
Get your water dealt with earlier than that one drops.
Sources and Stories Price Studying Your self
Circle of Blue, “Glen Canyon Dam Faces Its Existential Second”: https://www.circleofblue.org/2026/provide/glen-canyon-dam-faces-its-existential-moment/Excessive Nation Information, “The approaching failure of Glen Canyon Dam”: https://www.hcn.org/articles/the-coming-failure-of-glen-canyon-dam/Sierra Membership, “How A lot Longer Can Glen Canyon Dam Final?”: https://www.sierraclub.org/sierra/how-much-longer-can-glen-canyon-dam-lastGlen Canyon Institute, Decrease Basin states ask Inside to check a dam overhaul: https://glencanyon.org/lower-basin-states-tell-interior-to-study-overhaul-of-glen-canyon-dam/Missoula Present / Utah Information Dispatch, on the Reclamation memo and outlet works: https://missoulacurrent.com/glenn-canyon-dam/Coyote Gulch, evaluate of the river outlet works controversy: https://coyotegulch.weblog/2026/02/13/unpacking-the-controversy-over-glen-canyon-dams-river-outlet-works/U.S. Bureau of Reclamation, Glen Canyon Dam operations and 24-Month Research: https://www.usbr.gov/uc/water/crsp/cs/gcd.htmlU.S. Bureau of Reclamation, Put up-2026 Colorado River Operations: https://www.usbr.gov/ColoradoRiverBasin/post2026/index.html
The Reclamation technical memo on the river outlet works was authored by Richard LaFond, director of the company’s Technical Service Heart, in March 2024. Lake ranges on this piece mirror mid-July 2026 Bureau of Reclamation knowledge. Verify the dwell USBR trackers for present numbers earlier than you depend on them.
