Traveler Special Report: Grand Canyon’s Struggling River

Colorado River photo
The waning health of the Colorado River is impacting Grand Canyon National Park/Patrick Cone

By Kurt Repanshek

Standing in the morning sun on the right bank of the Colorado River at Lees Ferry, the gin-clear river jumps, leaps, and swirls through the rock gardens close to shore, belying its dwindling health. Most raft trips pushing off from the launch ramp just upstream pay me no concern, anxious to buck the rapids that make the Colorado River through Grand Canyon National Park renowned world-wide.

When the national park was established by Congress in 1919, there was no dam to slow the Colorado River as it poured out of the Rocky Mountains, sliced its way across the Colorado Plateau, and squeezed into a canyon with soaring ramparts of igneous, metamorphic, and sedimentary layers. Its ebb and flow were constrained only by the amount of snowmelt that came out of the high country each spring, and records show that the early 1900s, 1940s, and 1980s were particularly wet. But the past 60 years have brought development and climate change that have greatly changed the once-wild Colorado.

Today the river’s ill health starts nearly 700 miles away, at its headwaters on the western fringe of Rocky Mountain National Park. Metamoprhicallty, it goes from a nagging cough there to walking pneumonia in languid Lake Powell behind the Glen Canyon Dam. Then, figuratively and quite literally, it’s all downhill.

“The Colorado River is the lifeblood of a lot of things,” Jan Balsom, the chief of external communications and community affairs tells me the next day as we sit in the sun behind park headquarters not far from the lip of Grand Canyon’s South Rim. “It’s an economic lifeblood, but it’s also the lifeblood of the canyon. Some of the tribes refer to it as the backbone of their lives.”

All those aspects tied to the Colorado River are in jeopardy due to climate change and invasive species, a one-two gut punch conspiring to strangle the river in its own ecology. Death won’t come from drowning, but rather from choking on sand and vegetation, both native and invasive, that are a tightening noose around the Colorado’s neck.

Western snowpack graph

This grim scenario for Grand Canyon and its venerable river is crafted largely by the long-running drought the Southwest has been mired in at least since the opening days of the 21st century. Particularly dry stretches from 2002 to 2005 and again from 2012 to 2020 have taken a dire toll on the watershed. Declining snowfall in the river’s headwaters has greatly diminished runoff into the river and Lake Powell, which is predicted to stand at less than 30 percent of full pool by September.

While the U.S. Bureau of Reclamation, which operates the hydroelectric facility in the dam, has allowed roughly 8.23-million-acre feet of the Colorado River, on average, to flow through the dam and into the national park annually, that amount is expected to drop over the next two years by almost a million acre-feet due to reduced spring snowmelt. Look back over the past four decades and the river’s life has been staggered by drought.

“In ‘83, (the downstream release) peaked at around 93,000 cubic feet per second,” Balsom said. “Today’s peak flow is going to be around 22,000 to 25,000. Maybe we’ve had a couple high flows from Glen Canyon Dam that reached 45,000 (cfs). But it’s almost impossible now, with the lowered lake level, to even get to that level of flow.”

Those raging waters, along with giving the Colorado through the canyon its raucous personality, would carry sands and sediments along the way, materials necessary for building, and rebuilding, sandbars and beaches. But the recent years of diminished flows have greatly reduced the influx of sands and allowed vegetation to gain a foothold and then some. Most of the sediments that normally would be pushed downstream by the river are trapped behind the dam.

A Muted River

Today’s river is much different than the one Major John Wesley Powell and his crews battled in 1869 and 1871 on their historic river trips. Frederick S. Dellenbaugh, who was with Powell on the 1871 expedition, noted the raging river in a passage of his book, The Romance of the Colorado River.

“Down, and down, and ever down, roaring and leaping and throwing its spiteful spray against the hampering rocks the terrible river ran, carrying our boats along with it like little wisps of straw in the midst of a Niagara, the terraced walls around us sometimes fantastically eroded into galleries, balconies, alcoves, and Gothic caves that lent to them an additional weird and wonderful aspect, while the reverberating turmoil of the ever-descending flood was like some extravagant musical accompaniment to the extraordinary panorama flitting past of rock sculpture and bounding cliffs.” – Frederick S. Dellenbaugh, The Romance of the Colorado River, An Account of the Second Powell Expedition Down the Grand Canyon in 1871.

The day before I met with Balsom, I met Matt Kaplinski, a senior research associate at Northern Arizona University who has been running river trips through Grand Canyon since 1987. He was about to shove off from Lees Ferry on a two-week science trip through the Grand Canyon. Standing by the river as crews worked to ready the rafts, he explained that reduced flows through the dam had deprived the canyon of massive floods of churning water that would scour the river channel, pushing sandbars back and forth and downstream, and ripping out vegetation just starting to root in the sands.

“Why those sandbars are about the same size or bigger than they were (in the 1990s) is because once the flows were restricted, vegetation has migrated and established down to lower elevations on the sandbars,” said Kaplinski. “And those big sandbars are covered in pretty dense riparian vegetation right now, which essentially locks in that part of the sandbar from being eroded by flows from the dam.”

Keith Kohl, a U.S. Geological Survey geodesist – someone who measures and monitors the Earth’s size and shape to exacting calculations — who was leading the trip, was blunt in his summation.

“It was only 20 years ago where the lake was full, where now we’re at 37 percent, or something like that at Lake Powell. That’s tremendous that you could lose that much volume of water in just two decades,” said Kohl against the whine of pumps inflating rafts. “It’s really surprising that all of this infrastructure could get to a point where it’s worthless.”

Reservoir storage graph
The ongoing drought has left most reservoirs in the Colorado Basin states below normal/USDA

When the 710-foot Glen Canyon Dam choked the Colorado River at Page, Arizona, in 1963, it was called both an “engineering marvel” and the cause of “some of the most extensive and persistent scars of large-scale environmental modification.” 

Designed to create a massive reservoir holding 26.2 million acre-feet of water that for decades would slake the thirst of Arizona, Nevada, and California, the dam muted the river’s seasonal raging.

Prior to the raising of the dam, the river’s flow through the sinuous, nearly 280-mile-long canyon would average just under 8,000 cubic feet per second most of the year, according to data compiled by Kaplinski. But it would jump to more than 50,000 cubic feet per second for half the time in June when spring runoff peaked, and at least once every eight years there would be a deluge flowing at 125,000 cubic feet per second, the scientist’s research determined.

Historically, the greatest flood to roar through Grand Canyon came in July 1884. It was the result of the 1883 eruption of Krakatoa, which cooled the planet and led to a substantial snowpack in the Rocky Mountains. When runoff arrived in 1884, a flow estimated somewhere between 199,000 cfs and 228,000 cfs raced through the canyon.

That flood was documented by “an older timer living at Lees Ferry, who remembered that his cat had to climb a cottonwood tree, a certain branch in the cottonwood tree, and he was able to point that branch out to USGS water staff in 1921, I think,” said Dr. Larry Stevens, senior ecologist for Grand Canyon Wildlands Council and a conservation representative for the adaptive management of Glen Canyon Dam and the Colorado River through Grand Canyon. “They established that flow based on the elevation of that fork in the cottonwood tree at Lees Ferry.”

But even that flow was dwarfed by prehistoric floods approaching 500,000 cfs, said Stevens. “We did a paper in 1994, a paleo-flood analysis showing a flow of a half-million cfs there in the past, about 1,400 years ago,” he said. “And there were probably bigger flows than that as the glaciers melted off.”

But present-day, things changed drastically with the 1963 arrival of the dam, which corralled the huge outpourings that came with heavy snow years. While the U.S. Bureau of Reclamation, which operates the dam and its hydroelectric facility with eight electric generators, has in recent years tried to mimic those natural floods through “high flow experiments,” they haven’t come close to replicating the pre-Glen Canyon Dam floods down the Colorado River. Indeed, in a brochure the bureau touched on the impacts the dam brought to the river:

“As a result of the construction and operation of Glen Canyon Dam, the Colorado River ecosystem below the dam changed significantly from its pre-dam natural character. Before the dam was built, the Colorado River was a sediment-laden river that fluctuated in flow according to the seasons, rainfall, and inflows from side canyons. Now, the water released from the dam runs clear and cold without the springtime floods that once transported sediment, built beaches, and provided habitat for native species. Downstream from the dam, a new ecosystem emerged consisting of a mixture of native and non-native plant and animal communities.”

Another result of the dam is that any pounding thunderstorm that crosses the region and flushes sand, rock, and water down tributaries, such as the Paria River that flows into the Colorado at Lees Ferry, and into the canyon might lead to navigational hurdles for rafters by thinning the depth of the river with rocks and sediments pushed in from side canyons.

In short, the approach BuRec takes to operating the dam’s hydro station for power generation appears to conflict with the mandate of the Grand Canyon Protection Act of 1992 to operate the dam in such a way “to protect, mitigate adverse impacts, to and improve the values for which Grand Canyon National Park and Glen Canyon National Recreation Area were established.”

It’s debatable how closely BuRec has hewed to the act’s directive.  

“You don’t get the large flows from the dam anymore. We can’t even get 40,000 cfs; we might be getting 33,000 cfs, which is really only a meter or two meters of height,” Kohl pointed out. “I really see a point in the future where some of these boats have a hard time getting through. … My point is that one of these side tributaries may spill in, but there’s not enough flow coming from the side tributary to flush the main stem, so you’re gonna keep getting large boulders into the river and there’s no ability to flush them out with a dam.

“When the lake was full, they used the bypass tubes in the dam, you could get it up to well, 90,000 (cfs),” he said. “Right now, we can’t get 33,000. And 33,000 isn’t going to move a meter-size boulder. So everything that’s coming in can’t be moved under the current powers.”

Glen Canyon Dam photo
High flow releases through Glen Canyon Dam aren’t high enough to reflect historic flows through Grand Canyon/BuRec

But, Stevens told me, politics and the “law of the river,” which tries to balance the needs and demands of the Upper Basin and Lower Basin states that rely on the Colorado drainage, also factor into what BuRec can accomplish.

“I’ve been very impressed with their attention to that full phrase,” he said, referring to the act and BuRec’s efforts to live up to its directive. “The bureau is at least outwardly trying to coordinate discussion to facilitate, as much as possible, that mandate. But that mandate also includes the law of the river, which in many ways doesn’t much care about the environmental side of things.”

The multitude of interests linked to the water that flows down the Colorado has led to a 45,000 cfs cap on the high flows BuRec occasionally releases from Glen Canyon Dam, the ecologist said. 

“The coupling of love of the river with Grand Canyon Protection Act means that the decision has been made not to throw too much water downstream that’s not being used to produce hydroelectric energy,” Stevens said. 

Unfortunately, as Kaplinski noted, these lesser flows aren’t tearing out vegetation from the river’s sandbars and beaches. And while some of that vegetation is native, some isn’t. That growth also is affecting the look of the river corridor through Grand Canyon.

“The vegetation has been a pretty big change,” the Northern Arizona University scientist said. “People are very surprised when we report our results that the sandbars are as big as they were in 1990 or bigger, because the perception is that there’s not big open sandbars down here anymore as there were pre-dam. And that’s because they’re covered in vegetation, and it doesn’t look like a sandbar.”

Invasive tamarisk, a native to Eurasia and Africa that can push out native species and even alter wildlife habitat, according to the USGS, can be found in the canyon as well as native willows and Arrowweed. Mesquites also are descending lower into the canyon, in part because the disappearance of the massive seasonal floods allows them to take root, said Kaplinski.

Vegetation crew member photo
Crews are brought down to the floor of Grand Canyon National Park to remove invasive vegetation by hand/NPS file

The overall impact of this vegetation is that it basically “armors” the sandbars, he explained, and that is narrowing, or choking, the Colorado’s channel in some places. It’s not unique with the Colorado through the Grand Canyon, said Kaplinski. “The Green River, Upper Colorado, Rio Grande, you’ll see that in a lot of places,” he said.

Under normal scenarios and high runoff, the rivers would rip out much of the vegetation and prevent vegetation-heavy sandbars from slowly constricting the channels. In Grand Canyon, that vegetative encroachment is being battled by park crews through the use of “tamarisk beetles” that weaken the trees by eating its leaves and physically removing invasive species.

“The tamarisk beetle has pretty well taken care of many of those, which leaves us with stands of dead tamarisk, which then also have to be addressed,” said Balsom. “And then Arrowweed, which is a native, but it is taking over huge swaths of beaches. Pretty much our crews are going in and you have to repeatedly remove it. So, we’re working with our own vegetation crews, we’ve worked with some Native American youth crews and ancestral land corps crews, working with our tribal communities to target areas that they’re really concerned about, too.

“But we’ve got 277 miles worth of Colorado River in Grand Canyon, there’s a lot of beach. It’s hard to keep up with it,” she said. “So we’re targeting areas that have multiple resource values, recreational camping beaches being one, but also areas where we know that there are sensitive archaeological sites that require sand to be blown back up. And those of us who live in the West know that it’s windy a lot of the time, especially in the spring months, so that if you can actually open up those sandbars that wind will blow up and rebury those archaeological sites.”

A Dry Forecast

The Southwest’s ongoing drought doesn’t hold much promise for high flows through the canyon. Lake Powell is predicted to be less than a third full come this fall, a result of the fact that “(M)ountain snowpack, which is an essential source of water for Western rivers and reservoirs has declined by an average of 15-30 percent across the West since 1955,” according to Climate Central, a group of scientists and journalists that tracks the impacts of climate change.

Without an increase in snowpack and its seasonal runoff, or a massive release of water from upstream reservoirs Flaming Gorge and Fontenelle in Wyoming, Lake Powell will shrink to a “dead pool” elevation at which there’s not enough water to adequately power the hydroelectric facility, thus making the dam obsolete for generating power.

Colorado River Basin map
Seven states and Mexico comprise the Upper and Lower basins of the Colorado watershed/BuRec

“There’s still much discussion going on, and this is a very dire time for water in the Southwest,” said Stevens. “We’re down to less than two years of backup supply for 40 million people. The Colorado River provides that much support for that many people. And it’s not unexpected. The Bureau of Reclamation in 2012 published a report saying that there was almost a 20 percent chance of system failure at Hoover Dam (at Lake Mead National Recreation Area), not enough water to be able to deliver either water or power downstream.”

Looking upstream for a solution is not likely to be productive. While the Flaming Gorge and Fontenelle dams trap Green River water that could be passed on down to Lake Powell, the addition from a massive release would be trifling.

“Those are trivial reservoirs,” said Stevens. “There’s not enough water stored in those. Lake Powell stores, I think, 85 percent of the Upper Basin’s water.”

Back atop the South Rim, Grand Canyon Superintendent Ed Keable shared his thoughts about the river’s health as we sat in a small amphitheater used for ranger talks.

“Our chief concerns are managing the resource in a way that protects endangered fish,” said Keable. “We have two endangered fish in the Colorado River within the Grand Canyon, the humpback chub and the razor back sucker. Our scientists work with US Geological scientists and Fish and Wildlife Service scientists and others to understand the impacts of the flow of water in the Colorado River on those species.

“But we also have other interests,” he continued, pointing to recreation and tribal concerns. “Our tribal partners refer to the Colorado River as the lifeblood of the canyon. They have perspective, which I find really interesting and helpful as superintendent to, to think about, which is that the canyon and the river are living entities and that we have a responsibility to them to protect and preserve them as living entities. And so that’s a concept that I’m still learning about, but very cognizant of as superintendent, that they’re vital to the to the success of this park.”

How much water the various stakeholders, including tribes, have to work with remains to be seen. Currently, a 1922 compact guides how much Colorado River water goes to Upper Basin states (Colorado, New Mexico, Utah and Wyoming) and Lower Basin states (Arizona, California, and Nevada) plus Mexico. Tribal rights call for 20 percent of the river’s flow to be diverted to those tribes in the Upper and Lower basin states with “quantified water rights.” But population growth and the ongoing drought have started talks about reassessing water distributions in and between those basins.

“Right now, there’s still a guaranteed amount of water from the Upper Basin to the Lower Basin, which is this 8.23-million-acre feet a year,” explained Balsom. “The Bureau of Reclamation is starting to evaluate the amount of water that’s going to come from the whole series of dams from the headwaters all the way down.

“Glen Canyon marks the dividing point between the Upper Basin in the Lower Basin. There was a compact written in 1922 that divided all of this stuff, the waters between the Upper and Lower basins. Of course, they used the highest water years on record to estimate because they didn’t know anything else. And somehow they thought, ‘If we build it, it will come and we’ll always have water.’ And we know now that we won’t.”

During the first two decades of the 21st century, inflows into Lake Powell were below average for 15 years between 2000 and 2019. The outlook for a return to the early 1980s, when spring runoff filled the lake to the brim, is not promising. Through mid-June, 88 percent of the West was mired in drought, and extreme to exceptional drought conditions were noted in parts or most of Utah, Colorado, Nevada, New Mexico, and California.

U.S. drought monitor map

Talks underway in an effort to navigate the Upper and Lower basin states through the drought demonstrate the corner those who crafted the law of the river have painted themselves into.

“This has been expected through long-term tree ring analysis and looking at drought frequency in the Southwest,” Stevens said. “Now, faced with the reality of an actual crisis, this is where the rubber hits the road because decisions actually have to be made. The whole fallacy of appropriated water rights is coming to bear its full fruition of conflict, which is really the only product of appropriated water rights, conflict. It supports lawyers, but nobody else.”

At Grand Canyon National Park, Balsom said part of a possible solution is for society to know when to say no, and to stand by that.

“I think we have to take the long view on some of this stuff, and I think we have to be smart about it, too,” she told me. “And we’ve got to be smart with our infrastructure developments. We’ve got to be smart with minimizing our impacts to the land. We’ve got to be smart by not over-promising and under-producing.

“And we have to realize that you just can’t keep building, that at some point, you’ve got to say, you know, I think we’re good.”

This story on the health of the Colorado River and its impacts on Grand Canyon National Park has been supported by a grant from The Water Desk, an independent journalism initiative based at the University of Colorado Boulder’s Center for Environmental Journalism.

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