Would a Colorado River deal spell disaster for the Grand Canyon?

🥵 Aridification Watch 🐫

In response to last week’s dispatch on a potential new Colorado River sharing deal, Save The World’s Rivers! tweeted this compelling — but, for some, potentially opaque — tweet:

I say “opaque” because at first glance it might seem strange that a 50/50 split of the river’s waters between the Upper Basin and the Lower Basin would lead to ecological disaster. But it could, if, during a period of extremely low flow years, the 50% sent downstream was so low that it reduced daily flows through the Grand Canyon to a level that could not support fish or the ecology.

I’ve written about the faulty math of the Colorado River Compact many times here. Yet the assumptions of the river’s flow and the math are hardly the only, or largest, problems with the document. Most egregious was the exclusion of tribal nations from the original negotiations and the compact, itself, even though they collectively are entitled to a significant portion of the river’s waters. Under the compact, the tribal nations’ water rights must come out of the respective states’ allotments — that reduces tribes to subdivisions of the states, which they are not. They are sovereign nations and their water rights are negotiated with the federal government.

The other very big problem is that the compact never once considers the river, or the ecology that depends upon it. Instead, it apportions all of the water in the river and then some to “beneficial use,” which does not include environmental or even recreational uses. The compact also states that “the use of its waters for purposes of navigation shall be subservient to the uses of such waters for domestic, agricultural, and power purposes.” If we consider river-running and Lake Powell boating to be navigation, then the compact also deprioritizes those uses, i.e. recreation.

Because all of the Lower Basin’s water must flow through the Grand Canyon, the Lower Basin’s water rights serve as sort of de facto instream water rights through the canyon. In other words, the more water the Imperial Irrigation District and other Lower Basin users demand for irrigating alfalfa, the more water there is for fish and other critters in the Grand Canyon (including river runners). So, if the states were to strike a deal that might allow the Upper Basin to send only a trickle to the Lower Basin, it would also result in a mere trickle flowing through the Grand Canyon.

The thing is, the fish and even the river runners don’t really care much about the annual volume of water in the river, they care more about the daily streamflow. And that is currently regulated by a separate set of rules aside from the Colorado River Compact that were implemented in the 1990s.

But first, let’s go back in time to the years before there was a Glen Canyon Dam. Back then, the Colorado River through Glen Canyon, Marble Gorge, and the Grand Canyon was truly wild. Seasonal streamflow fluctuations were extreme, swinging from as low as 3,000 cubic feet per second in late summer, fall, and winter, to 80,000 cfs or more during spring runoff and late summer monsoonal floods. The water was often laden with orange-red sediment, and in the summer its temperature might reach 80° F or higher, giving it a viscous, dirty-bathwater feel. It may not have been great for swimming in, but the native fish reveled in it.

The completion of Glen Canyon Dam in 1963 changed all of that. Annual flows were evened out to build up storage in Lake Powell while also meeting Colorado River Compact obligations. Seasonal fluctuations were also no more, and the silt-free, murky green water emanating from the dam was a near-constant 46° F. Daily fluctuations of streamflow, however, could be erratic and downright manic, depending on the power grid’s need for more juice.

Before there was a Glen Canyon Dam, the Colorado River ran wild and free, often topping out at Lees Ferry at or above 100,000 cubic feet per second, which is ginormous. After the dam was completed, managers withheld flows to fill up the reservoir. Then, in 1983, they withheld too much water, and a massive spring runoff threatened the dam itself, forcing managers to release nearly 100,000 cfs once again and providing a wild ride for Grand Canyon river runners. After the 1996 operations plan was implemented, occasional high-flow releases occurred to help move sediment through the Grand Canyon in an effort to benefit the riparian ecology and build new beaches. But they still pale in comparison with pre-dam high flows. Data source: USGS.

During the first few decades after the dam was completed, the hydropower plant operators had ample leeway to “follow the load” by modulating the flow of water through the turbines. This occasionally caused huge fluctuations in the flow of water through the Grand Canyon. On one July day in 1989, for example, about 3,471 cfs was running through the dam at 5 a.m., a meagre flow by the Colorado’s standards. By 3 p.m., it had jumped to 29,000 cfs—the maximum flow through the turbines—to generate juice to the burgeoning number of air-conditioners on the Southwest power grid. This must have wreaked havoc on river runners in the Grand Canyon, who might have tied up their boats during high flow, only to find them beached out several hours later (or vice versa, depending on how far downriver they were). It probably wasn’t so good for the fish, either.

In the early ‘80s, dam operators wanted to maximize the potential for following the load by also installing turbines in the river outlets so they could generate even more power by releasing more water, which likely would have exacerbated daily fluctuations. The proposal was shot down following intense opposition, and sparked an effort to develop a more river-friendly plan for managing the dam.

Congress passed the Grand Canyon Protection Act in 1992, and in 1996 Interior Secretary Bruce Babbitt signed off on the Glen Canyon Dam Operations plan, selecting the “Modified Low Fluctuating Flow” alternative — a compromise between environmental and power-generating interests — and creating an adaptive management working group. The annual releases would remain the same (8.2 million acre-feet), but it imposed minimum and maximum release rates and maximum fluctuation rates, along with adding in occasional high-flow events meant to simulate pre-dam seasonal fluctuations. This limited Glen Canyon Dam’s flexibility as a hydroelectric plant, but it was far better for the downstream river and its users.

A profile of the Colorado River with potential future dam and reservoir sites. From the 1916 USGS paper “Colorado River and its utilization,” by E.C. La Rue.

Yet in the ensuing three decades, power-generation has often taken precedent over downstream ecological health, and the Grand Canyon’s riparian environment remains imperiled. (As long as we’re talking about ironies: A portion of revenues from Glen Canyon Dam’s power sales fund endangered fish recovery efforts.)

Whether a new deal to share the Colorado River becomes an ecological disaster would seem to depend less on the annual volume released from Glen Canyon Dam than it does on the daily and seasonal operations of the dam. And I would add this to the above tweet: It would be the second ecological disaster for the Grand Canyon; the first was the construction of Glen Canyon Dam, itself.

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As long as we’re talking streamflows … here’s a hydrograph of the Animas River in Durango for the last year (July 17, 2024-July 17, 2025) and for the same time period during the previous year. You can see that spring runoff this year was lower, and less drawn-out than in 2024, and that the current streamflow is about 25% lower than it was on this date last year. Hopefully the monsoon will arrive soon and boost flows, at least for a bit.

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🤯 Trump Ticker 😱

While everyone is going bananas over the Trump/Jeff Epstein brouhaha, the Trump administration is putting its fossil fuel fetish on garish display. This includes:

• Yesterday the Interior Department said it would subject proposed solar and wind developments on public lands to elevated scrutiny in an effort to end “preferential treatment for unreliable, subsidy-dependent wind and solar energy.” Meanwhile these guys have been eliminating environmental reviews for and public input on oil and gas and mining projects. So who’s getting preferential treatment now?

• Meanwhile, the Environmental Protection Agency is trying to block the state of Colorado from pushing dirty coal plants to close as part of its effort to reduce air pollution and, well, comply with EPA air quality regulations. CPR’s Sam Brasch has the story, and reports that Colorado’s not about to take this one lying down.

• And, the EPA continues to defy its name by extending the deadline for compliance with regulations for managing coal combustion waste, or CCW. Coal combustion waste is the solid stuff left over from coal burning, like ash, clinkers, and scrubber sludge, and it contains copious quantities of nasty stuff like mercury, arsenic, boron, cobalt, radium, and selenium. This is an enormous waste stream, and is piled up outside coal plants and in coal mines all over the West. Check out this map from Earthjustice to see where the coal waste depositories are near you!

• And finally, U.S. Energy Secretary Chris Wright, in an Economist column, wrote that climate change is “not an existential crisis,” merely a pesky little “by-product of progress.” He said he was willing to take the “modest negative trade-off” of climate change—along, presumably, with the heat waves, wildfires, and devastating floods—"for this legacy of human advancement.” It’s almost as if they like pollution! It would be funny if it weren’t so tragic.

😀 Good News Corner 😎

Colorado has new wolf pups! Yes, Colorado Parks and Wildlife has confirmed three new wolf families have joined the Copper Creek Pack with new pups, though they have not released the number of pups in each family. This is good news, indeed.

“Like so many Coloradans, I’m thrilled to hear of new wolf families and puppy paws on the ground,” said Alli Henderson, southern Rockies director at the Center for Biological Diversity, in a written statement. “The howl of wolves rising once more in this iconic landscape signals real progress toward restoring balance in Colorado’s wild places.”

For more background and history on wolves, check out my essay from a little while back on wolves, wildness, and hope. But you’ll have to sign up as a paid subscriber to read it, since the archives are behind the paywall!