The Arizona Republic
A journey to the heart of a river forever changed by human hands
About this series
Our team spent 16 days rafting through the Grand Canyon. We interviewed scientists, government officials, river runners, Canyon guides and others. Today: Glen Canyon Dam altered the flow of the Colorado River and turned its ecology upside down.
Monday: On the Little Colorado River, scientists try to keep one of the Canyon’s last native fish from going extinct.
Tuesday: Environmental groups have argued that the only way to save the Grand Canyon is to tear down Glen Canyon Dam.
Now at azcentral.com: “An Unnatural Wonder,” our new documentary.
LEES FERRY — The biologist eased off her jet boat’s throttle as she cruised the Colorado River in search of the bugs that feed the Grand Canyon’s water-dwelling wildlife. She hopped ashore to inspect a jumble of half-submerged boulders.
There she found a film of midge eggs roped together in a sort of snail’s trail about 6 inches above the waterline. The line was a marker of where water released through Glen Canyon Dam’s hydropower turbines had elevated the flow the previous evening, when the gnat-like insects had cemented their offspring on what were then wet rocks.
Overnight, the Southwest’s power demand had declined as usual, reducing the flow of water from Lake Powell through the dam, and into one of the world’s most engineered and manipulated rivers.
“They laid their eggs probably at dusk last night,” U.S. Geological Survey biologist Megan Daubert said at the boulders about two miles downstream of the dam, “so now they’re high and dry.” The desert-baked eggs would never hatch.
Our thirst for power had swindled Grand Canyon’s food chain.
In the 55 years since the federal government poured more than 5 million cubic yards of concrete across the Colorado River to form Glen Canyon Dam, the demand for water and electricity in Arizona,
Nevada and California has turned the river’s ecology upside down.
A river once wild, muddy and warm now flows cold and clear, every drop measured out to supply cities and farms downstream. Water levels ebb and flow hourly, erasing the spring surges and summer droughts innate in desert rivers. Scientists manage nature’s cycles, adding what was lost, nursing what remains.
In this unnatural resource, millions of visitors enjoy a curated experience, riding whitewater rapids controlled by a power plant, catching freshwater trout imported from cooler climates, camping on beaches built by artificial floods.
Ecologists say it’s possible to maintain a living river, but not the one that existed before the dam was built. That river is gone forever. In its place is one that must be managed forever, saving only the parts that people value most.
“The Colorado River in Grand Canyon is not a native ecosystem,” said Jack Schmidt, a Utah State University geomorphologist and former director of the Grand Canyon Research and Monitoring Center in Flagstaff.
What is it then?
“A novel ecosystem,” Schmidt said, and “still the world’s most awesome experience.”
The human hand is everywhere
Nearly 6 million people peer into Grand Canyon each year and a tiny fraction descend the mile-deep chasm. Fewer than 30,000 of them float the river over its renowned rapids and past the fluted slot canyons, the thirsty bighorn sheep, the ancient cliffside granaries and the gaping slabs of sedimentary and volcanic rock that block out the modern world.
The days and weeks of solitude and raging waters on such an outback adventure imprint a wondrous illusion of nature on the canyon. But to the alert eye, the modern human hand is everywhere.
It’s in the water that’s clear green and cold instead of muddy and warm. It’s in the few remaining beaches that damblocked floods would otherwise churn up. It’s in the Eurasian tamarisk trees, first brought to the U.S. to check soil erosion, that have crowded out the native cottonwoods and willows that foster birds along the water.
Could it also be in the lack of bugs that live in almost every other river from Mexico to Alaska, dammed or not?
Midges still swarm the Colorado River from Lees Ferry downstream through the Grand Canyon to Lake Mead, the other dammed reservoir that bookends one of America’s most visited and revered national parks. At points on Daubert’s winding aquatic insect search, the tiny bugs appeared like sleet flurries before the speeding boat, pelting her face at 40 mph.
But experts who study the native fish and the introduced trout that eat them – or the swallows feasting by morning, or the bats darting by evening – say the river’s insect population offers less nourishment to go around than a healthy environment would provide.
For starters, the midges are practically the only fish food around. The Grand Canyon stretch of the Colorado lacks for the mayflies, stoneflies and caddisflies that periodically drift on and above most of the West’s rivers. USGS classifies this stretch as one of the world’s least-productive rivers for aquatic insects, in the bottom 10 percent.
These long-winged insects – mayflies looking like shortened damselflies, caddisflies like mini moths, stoneflies like skinny beetles – all would provide fish a bigger mouthful.
But they’re not here.
The water’s nightly fluctuations could be to blame for this, or for untold millions of unhatched midge eggs.
Daubert’s bosses at the USGS aimed to find out. This past summer they worked with the Bureau of Reclamation to keep water releases level every weekend, when power demand is generally lower than during the rest of the week. These so-called bug flows would help determine whether more midges hatch when eggs can stay wet overnight and whether other species currently confined to side canyons creep into the river and head upstream in more favorable conditions.
Several factors, including water temperature, algae to feed insects and sand distribution could influence the bugs that are available for Grand Canyon’s fish. The idea behind the bug flows is to test whether the right egg-laying conditions are more important than those other factors.
USGS research ecologist Ted Kennedy is eager for clues as to why the river here won’t support the same insects that swarm it upstream at Utah’s Cataract Canyon, or that anglers mimic with their fly casts downstream of Flaming Gorge Dam on the Green River.
“These kinds of insects are really ubiquitous,” Kennedy said. “They’re found throughout the world.”
Even if the stable flows don’t attract more insect species, USGS and the National Park Service expect them to crank up midge production by at least a quarter. Starting in the experiment’s first week in May, Kennedy noticed much larger swarms than he has seen in his 15 years on the river.
“It’s buggy out there,” he said. Relying solely or mostly on midges is a dangerous game for endangered species. Like a stock portfolio, Kennedy said, the fish should have as diverse a menu as possible for long-term stability.
There’s no going back
Can tinkering with flows do the trick? Or will it take more radical, even unnatural, intervention?
It’s the kind of question that applies to almost every ecological treasure below the dam.
The nature of today’s Grand Canyon provides both a pleasure and a puzzle for nature seekers, precisely because it is not, by most definitions, natural.
The 280-mile gorge creates an astonishing icon for a 1,450-mile-long workhorse river that provides vital recreational and ecological oases before disappearing into a series of canals and pumps that keep its water from reaching its mouth in the sea.
The National Park Service’s mission includes preserving nature. In this case, a park official said, that means maintaining and restoring a “naturalized” ecosystem without further losses.
“I think we all realize it’s a naturalized system,” said Jan Balsom, the park’s senior stewardship adviser. “Our work is to try to re-establish natural processes as much as possible without damaging the system more than it already is.”
Americans hold the keys to the Canyon’s future. They could shape a new novel ecosystem. Their government could dial up a whole spectrum of outcomes, each based on a shifting set of human values.
There’s no going back to a natural, pre-dam river, even through many an environmentalist’s fondest dream is tearing down the dam, Utah State’s Schmidt said. Too much has changed, including the upstream scourge of nonnative bass and other predators that would zoom in and snarf Grand Canyon’s endangered humpback chub.
Americans need to know that Grand Canyon is a carefully controlled experience, Schmidt said, so they can think about how they might want to shape a future ecosystem as demands on the river grow.
Turn the dam’s levers one way and you might help bugs, native species and recreation. Turn them the other and you might boost hydropower, or the region’s water bank.
Or, in the face of drought-inducing climate change, nature could make many of the decisions after all by draining Lake Powell to levels where the options are few and massively expensive.
Longing for a free-flowing river
Daniel Brown hucked a lure from the stern of his beached raft on the first night of his float trip down the Colorado River in May. He pulled in a footlong rainbow trout from one of the riffles off the sandy beach where he was setting up a camp kitchen.
It was one of several trout the Grand Junction-based river runner would land from beach camps over the next two weeks, only to unhook the fish and watch them wriggle away into waters where he knew they wouldn’t belong or survive if not for the dam.
He wondered why none of the trout he had caught on six trips through Grand Canyon ever seemed to grow any bigger.
Each mile he moved downstream from the dam allowed the sun to warm the water slightly from the chill it carried as it flowed into the river from the depths of Lake Powell. The farther he got from the dam — creator of the artificial coldwater fishery — the fewer trout he caught.
There was no mistaking the human influence on the river and its fish, and he had come to a sort of peace with that reality even if he would prefer to see only humpback chubs or their one-time canyon predators, the salmon-size Colorado pikeminnow that disappeared from this part of the river after dam construction.
“River runners long for that natural, free-flowing river because, honestly, you want your experience to be as pure as possible,” Brown said, “and that’s most likely to happen when it’s in its natural state.”
The slender former raft guide, who now directs a non-profit recreation service, started mornings with his travel companions by sharing advice for negotiating the day’s rapids, which would be provided “courtesy of the Bureau of Reclamation,” the federal agency that runs the dams and controls the flows.
The dam isn’t going anywhere soon, he said. “We need to accept that yes, human impact has created some changes that have a lasting effect.”
Still, he hopes that everyone who learns to love the Canyon will advocate for saving the natural parts that remain: the fish, bighorns, willows, chuckwallas and more. They’re a part of the experience he seeks with each return, a sense of connection to the ancient Native Americans who lived here, or to John Wesley Powell, whose daring 1869 expedition of the then-untamed river made it legend.