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.

U.S. Geological Survey biologist Megan Daubert navigates the Colorado River while collecting bug traps near Marble Canyon. Experts say the river’s insect population offers less nourishment to go around than a healthy environment would provide. Michael Chow/The Republic

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.”

HOW WE DID THE STORY: To get a close-up view of the Colorado River through the Grand Canyon, reporter Brandon Loomis and photojournalist David Wallace joined a 16-day raft trip covering the entire length of the Canyon. Along the way and before and after the trip, they interviewed scientists, government officials, river runners, Canyon guides and others. To get a close-up view of the Colorado River through the Grand Canyon, reporter Brandon Loomis and photojournalist David Wallace joined a 16-day raft trip covering the entire length of the Canyon. Along the way and before and after the trip, they interviewed scientists, government officials, river runners, Canyon guides and others. SEE THE VIDEO

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 dam-blocked 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?

Unnatural wonder: A 16-day journey to the heart of the Colorado River Since the gates of Glen Canyon Dam were closed in 1963, the ecology of the Colorado River in the Grand Canyon has been altered, some fear forever. David Wallace and Michael Chow/The Republic, Arizona Republic

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 non-native bass and other predators that would zoom in and snarf Grand Canyon’s endangered humpback chub.

Ezra Jones takes in the canyon walls from his kayak on the Colorado River, on May 19, 2018, one of fewer than 30,000 people a year who experience Grand Canyon National Park this way. David Wallace/The Republic

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.

Show caption Hide caption River runner Daniel Brown fishes in the Colorado River near the confluence with Blacktail Canyon in Grand Canyon National Park. Non-native trout have flourished here,... River runner Daniel Brown fishes in the Colorado River near the confluence with Blacktail Canyon in Grand Canyon National Park. Non-native trout have flourished here, and some say they've had a negative impact on the native species of fish. David Wallace/The Republic

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.

Giving up on chubs because the future is for trout would be like ignoring climate change because that’s easier than acting on it, he said.

“It wouldn’t be the prudent thing to do, to say there’s nothing more to do to stop that.”

As Brown and friends whisked down the churning river, Randy Van Haverbeke, a U.S. Fish and Wildlife Service biologist, waded in the Little Colorado River some 78 miles downstream of the dam, above where that gentle blue tributary flowed into the mainstem. He fished out hoop nets he had placed to trap chubs, flannelmouth suckers and pinky-size speckled dace.

He and crewmates had camped just over a mile upstream, to the Little Colorado's slower and warmer waters. They came to sample the native species’ populations and scan electronic tags to track their movements since their last capture.

The team worked mornings until triple-digit heat drove them into the shade of a boulder at camp. The Little Colorado there flows past reeds and tamarisk thickets under red and tan mesas with blackened cliff bands.

It’s a remote wilderness with constant reminders of human society. Soda bottles and other plastics flow down dozens of miles from U.S. Highway 89 and beyond, while rafters stream up from the Colorado for a dip in the relatively warm water.

It’s also a chub paradise.

Show caption Hide caption Randy Van Haverbeke, a senior fish biologist with U.S. Fish and Wildlife, tosses a humpback chub back into the waters of the Little Colorado River... Randy Van Haverbeke, a senior fish biologist with U.S. Fish and Wildlife, tosses a humpback chub back into the waters of the Little Colorado River as Rick Deshler, a biological technician with U.S. Fish and Wildlife, looks on near the confluence of the Colorado River in Grand Canyon National Park on May 20, 2018. David Wallace/The Republic

The chub is a silvery predator of insects and some fish, with a forked tail and a knob between its head and dorsal fin that gives it the namesake hump. In warm-enough water it can grow to a foot.

Van Haverbeke and two crewmates huddled under an umbrella meant to shade the screen of a malfunctioning computer. They scanned the fish with an electronic wand to read the identifying numbers on those specimens bearing tracking tags, and injected tags with a syringe under the skin near the pectoral fins and bellies of those lacking them. They measured and read off lengths to be recorded by hand.

“Three hundred-fifty!” Van Haverbeke shouted when noting the millimeters — a little more than 12 inches — that one of the day’s larger catches stretched. “The whopper.”

They planned to keep some of the young, for temporary transplant upstream above a waterfall with the Navajo Nation’s cooperation, or to a fish hatchery in New Mexico. Each place would allow the fish to grow unmenaced by trout, until they could return to the Canyon with an adult’s girth too wide for a trout’s mouth.

The crew caught about seven fish per net on their second day in camp, after having snared 15 a net the previous day, when fewer of the fish were wary. They monitored 20 nets, while crews miles upstream checked another 60, and they expected to catch about a tenth of the fish in each pool of the river.

Van Haverbeke used to spend a week of every month here, back in the 1990s when the chub seemed on the brink of extinction. But these are relatively good times for Grand Canyon chubs, and the government knows more about their population than ever before. Now he comes in from Flagstaff for three of his agency’s four quarterly surveys.

Show caption Hide caption A humpback chub is ready to be released back into the waters of the Little Colorado River near the confluence of the Colorado River in... A humpback chub is ready to be released back into the waters of the Little Colorado River near the confluence of the Colorado River in Grand Canyon National Park. Randy Van Haverbeke of U.S. Fish and Wildlife was catching, tagging, and measuring native fish in the Little Colorado River, including the endangered chub. David Wallace/The Republic

The latest published estimate of chubs in the Colorado around its confluence with the Little Colorado is 11,000 adults. That’s a comfortable-enough rebound from the 2,000 or 3,000 that swam here in the early '90s that the government is proposing to downgrade the chub’s protected status from endangered to threatened.

There may be factors beyond temperature at play.

Some biologists believe a healthy crop of algae is feeding tiny non-native shrimp known as scuds, which in turn fatten the chubs. Another non-native, the New Zealand mud snail, can close a hatch on its shell and avoid being digested in a fish’s gut.

Ironically, it is those chubs most affected by Glen Canyon Dam that are pulling the species away from the endangered list, and not the ones living upstream in the warmer and less-regulated flows through Utah. Up there, non-native predators such as bass are gobbling up the chubs, while fewer warmwater predators have invaded Grand Canyon.

“The fish are seemingly never out of danger,” the sun-beaten biologist Van Haverbeke said after plunging into a blue pool in the Little Colorado to cool off. “But this has been a good sanctuary for them here.”

For about a half-century, it could be argued, the Little Colorado was the only thing that saved the chubs of Grand Canyon.

Show caption Hide caption A rainbow trout is hooked by a fly fisherman on the Colorado River near Marble Canyon. The non-native fish were introduced into Grand Canyon waters... A rainbow trout is hooked by a fly fisherman on the Colorado River near Marble Canyon. The non-native fish were introduced into Grand Canyon waters for recreational anglers and have been known to dine on the river's endangered humpback chub. Michael Chow/The Republic

The first shock that Glen Canyon Dam delivered to the chub was cold water. The power plant drew the water from the reservoir’s lower depths, where it was shielded from the sun. The fish that had routinely experienced water temperatures around 20 degrees Celsius suddenly contended with 10 degrees or colder. Biological literature, which measures in Celsius, generally suggests the species needs about 16 degrees to spawn. Van Haverbeke said they will spawn at somewhat cooler temperatures.

For years the fish spawned mostly in tributaries like the Little Colorado, uncooled by dam releases.

After the temperature plunge came the rainbow trout, planted for recreational angling and thriving on the newly cold water. The temperature and trout worked together to threaten chubs in the Colorado, Van Haverbeke said, because young chubs don’t grow in cold water. A chub that might normally reach adult size in three years could still appear a juvenile after twice that if the temperature is 10 degrees Celsius.

Rainbows favor insects and aren’t frequent fish eaters, but the cold water could suppress a chub’s growth so long that a trout would eventually get around to eating it.

The National Park Service eventually removed some of the trout, and now proposes a new program to kill brown trout that are colonizing Lees Ferry below the dam. But what seems to have preserved the chub through decades of cold water was the unique safe harbor off-river in the Little Colorado.

The milky-blue water that’s visible except during muddy monsoon floods flows 20 degrees Celsius — 68 Fahrenheit — out of a super-carbonated spring, and its fallout builds white calcium-carbonate terraces on its way toward the Colorado. Trout don’t seem to like the saturated minerals, or the warmth, or the mucky seasonal floods.

“It’s warm and salty and blue, or it’s raging mud,” which are the conditions that evolved chubs, Van Haverbeke said. “They probably can sense prey better in the mud (than trout can).”

An endangered fish rebounds

So the Little Colorado saved the chub, but likely didn’t trigger its recent recovery. For that, Van Haverbeke said, the species can thank extended drought.

The Colorado River has suffered through mostly dry winters since the turn of the 21st century, offering less springtime snowmelt to refill Lake Powell than the dam’s engineers had counted on. As a result the reservoir now sits about half empty, and the dam’s hydropower water intake is closer to the warm surface. The turbines now churn and release warmer water than when the reservoir was full.

Van Haverbeke remembers when the river flowed at 10 degrees Celsius — 50 Fahrenheit — at its confluence with the Little Colorado. “You’d go down (in it) and get an ice cream headache,” he said.

By 2006 the river flowed there at 16 degrees, or nearly 61 Fahrenheit

It seemed to make chub comfortable, and holdout populations with just dozens of members started swelling to the hundreds on the mainstem Colorado within 50 miles of the dam.

Aqua-blue, calcium carbonate-rich water from the Little Colorado River (left) mixes with water from the Colorado River in Grand Canyon National Park. David Wallace/The Republic

But the Little Colorado and associated upper-Canyon habitats are no longer the undisputed epicenter of native fish activity in Grand Canyon. More than 100 miles downstream, in parts of the western Canyon that appeared virtually devoid of chubs and flannelmouths in the '90s, hoop nets now haul up a hundred pounds of them at a time for measurements.

Down there, where the sun has had longer to warm Glen Canyon Dam’s releases, chubs have “exploded” in this decade, Van Haverbeke said. The Fish and Wildlife Service is only beginning to quantify them, but he believes there are now more chubs in the western Canyon than the 11,000 around the Little Colorado.

Last spring he found a female chub oozing eggs there in the river, something he had never seen except in warmer tributaries. It suggested to him that the river itself is the chub’s preferred spawning habitat if its water is warm enough.

The National Park Service officials say the rebound in the western Canyon is the result of trout control, chub relocations to the area and temperature — not just one of those.

Whatever the cause, if the trend holds it will be a rich reward for a small cadre of Flagstaff biologists’ decades helping and promoting a seldom-seen fish that is as old a Grand Canyon icon as the river-carved canyon walls themselves.

“If you go anywhere outside of Flagstaff nobody cares about the humpback chub,” said Kirsten Tinning, a former Arizona Game and Fish Department biologist. She now volunteers on Van Haverbeke’s crew because the work “feeds my soul.”

“It’s this tiny group we’ve kept together for 30 years,” she said. She hopes a new generation will take up the cause.

Why should people care about lumpy-necked fish they may never see?

“They’re special,” Van Haverbeke said. Their pulse is the ancient Canyon's pulse. “They’re a living part of the Grand Canyon."

Put simply, he said: “They belong here.”

A huge block on the river

Daubert cruises the river weekly to collect insects and help quantify the available fish food.

The young biologist visits sites every mile or so near the dam and Lees Ferry where her crew has placed twin petri dishes Velcro-strapped back-to-back on a reed-thin post and coated with a gluey film to catch insects on the breeze. Some of the sites also have timer-activated traps that attract bugs in the hour after dusk and kill them when they fall in a dish of antifreeze.

At one of her stops she rolled a cigarette and thought out loud about why she never traps much more than midges and moths, or beetles that rarely enter the aquatic food chain.

Some colleagues on the Colorado’s upstream tributaries have found hundreds of caddisflies in their traps, she said.

“There’s a huge block on the river that’s definitely changed it,” she said, though the effect on insects isn’t certain.

“This river is freakin’ cold,” she said. She knows this firsthand, from the times she has to reach or hop overboard to rake vegetation out of the jet boat’s intakes. “But if you go to Tapeats Creek, that’s just as cold.”

Tapeats is full of the mayflies and other species that would fatten fish throughout Grand Canyon if they migrated up the Colorado.

“They’re indicator species,” she said.

Their absence indicates the native fishery’s limits.

As emblematic as chubs have become for Grand Canyon conservation, a far broader web of wildlife relies on a healthy Colorado. From headwaters to delta, more than two-thirds of the species in lands drained by the river rely on it for at least part of their lives, said Jennifer Pitt, the Audubon Society’s Colorado River project director.

The sun sets over the Colorado River at Horseshoe Bend in the Glen Canyon National Recreational Area near Page. Michael Chow/The Republic

“Aquatic habitat and healthy riparian habitat is of enormous importance,” she said.

Equally important to conservation, though, is the Southwest’s water demand. Without adequate water in the reservoirs for human consumption, there’s little left for nature. That’s why groups including Audubon have pushed for an interstate agreement on water conservation.

“We will lose (wildlife) if we can’t fix the human equation at the same time,” Pitt said.

A trout fishery where there was none

Arizona’s trout anglers have their own fears for the river’s future — and a plan that some advocates fear could jeopardize chubs.

Brad Powell fishes Lees Ferry every year, catching and releasing iridescent trout that frequently land in the trophy size class. Some years are better than others, apparently owing to insect availability, and the Phoenix-area resident would like to see more stability in the population.

Unlike chubs, trout drive jobs for fly-fishing guides and innkeepers in the Marble Canyon area.

“It’s the premier trout-fishing water in the state,” Powell said. “I don’t think a lot of people in this state know we have such a world-class resource up there.”

Powell leads regional fish conservation efforts for Trout Unlimited, which counts 2,000 members in Arizona. That makes it one of the largest sporting organizations in a state known more for its hot deserts than its cold waters.

“We’d like to figure out a way to have a sustainable trophy fishery,” he said, “not one that ebbs and flows every few years.”

Stephen Sanborn fly fishes above Soap Creek Rapid in Grand Canyon National Park. Unlike the Colorado River's native humpback chubs, the popular rainbow trout drive jobs for fly-fishing guides and innkeepers in the area. David Wallace/The Republic

He and biologists at Arizona Game and Fish think stocking more rainbows — altered to prevent their breeding — could help take pressure off the wild trout while also boosting the river’s reputation by increasing catch rates. Anglers currently average more than the hour of effort per fish caught that the state has set as a goal.

Those biologists met with guides and a few concerned environmentalists near Lees Ferry last winter to explain their plans. They would stock up to 16,000 trout a year whenever the area’s fishery needs a boost, and would expect most of those to be caught or otherwise die before the season’s end. Their statistical analysis suggested few of the stocked fish would drift downstream into the chub’s zone at the Little Colorado, and those that did would eat only 12 chubs over 20 years.

The extra fish, while not trophy size, would help restore some sizzle to a fishery whose attraction has waned since a population crash from an estimated 1.2 million trout in 2012 to 375,000 this year — a crash evidently brought on by insufficient insects for fish food.

Environmentalists in the crowd wondered why the state would push back against a fish famine by boosting the population. State biologists said the stocked trout would be a temporary blip with little influence on the wild population’s diet, and guides said a higher catch rate was vital for rebuilding business.

Show caption Hide caption Hualapai tribal member Daniel Powskey sings a native song in Blacktail Canyon, a side canyon drainage of the Colorado River in Grand Canyon National Park.... Hualapai tribal member Daniel Powskey sings a native song in Blacktail Canyon, a side canyon drainage of the Colorado River in Grand Canyon National Park. The Hualapai Indians' traditional homeland stretches for over a hundred miles along the Grand Canyon. David Wallace/The Republic

Some regional Native American tribes, for whom the Little Colorado is sacred ground, remained skeptical — especially given that the National Park Service is proposing to kill trout in the same area to protect chubs.

Park officials are studying the possibility of electric shock or other methods to remove brown trout that are expanding their population in Lees Ferry. Browns are far more likely to eat fish than rainbows, and the idea is to stun all the fish but remove only the browns.

Grand Canyon National Park already has a program that has removed browns in this way from Bright Angel Creek, a trout spawning area deep in the park from which the agency feared a runaway population could devastate chubs.

Tribes historically have argued for conserving native species including chubs, while also opposing killings of non-natives except for human consumption.

“We spent years trying to get rid of trout out of that river,” said Michael Yeatts, an anthropologist for the Hopi Tribe. “All of the sudden we’re looking at putting the trout in?”

A new stocking program could lead to the deaths of both chubs and trout, he feared.

“Just let them be,” he said.

Powell, the trout angler, opposes brown trout removals at Lees Ferry, at least until studies can prove that those trout are killing chubs. His concern isn’t for the browns, but how the stress of an electric shock may affect the rainbows that would remain in the river.

Park officials are considering more selective measures, such as paying anglers or tribal youths to catch and eat browns. The goal is to encourage people to use and enjoy the fish, and not to commercialize killing and indiscriminate disposal.

“We’re going to try to avoid the term ‘bounty,’ but rather use the term ‘restoration rewards,’” the National Park Service’s Colorado River program coordinator, Rob Billerbeck, told colleagues at an interagency dam management meeting last summer.

Van Haverbeke, the federal chub biologist, doesn’t advocate a wholesale trout slaughter when people enjoy catching trout.

“Let’s say you remove all the brown trout from Lees Ferry, if you could even do that,” he said. “Well, you’re not making friends for the chub.”

Instead, he worries most about the river’s temperatures. And, ironically, the more “natural” those temperatures get, the more he worries.

Smallmouth bass, despite their names, have bigger mouths than trout. They can latch onto chubs of any size, and do so at a rapacious rate in the warmer waters upstream of Lake Powell, where they and other alien predators dumped into the river at various times have established populations.

Flathead catfish pose similar threats in the warmer areas downstream of Grand Canyon.

So far, Van Haverbeke believes, the cooler waters coming out of Lake Powell have discouraged those species from entering the park. The drought that has warmed those waters has helped chubs, he said, but continued warming could invite new predators and a collapse.

“At this point the dam is almost acting to preserve the humpback chub in Grand Canyon,” he said.

His boss back in Flagstaff put that irony more bluntly. Glen Canyon Dam — the great destroyer of Colorado River fish habitat — may be the only hope for Grand Canyon chubs, Fish and Wildlife Service supervisory biologist Kirk Young said.

“I don’t think there would be chubs in there if the dam wasn’t there,” Young said.

Faced with the choice of an unnaturally cold river that chubs will have to tough out, or a historically more natural warm river, Young would prefer cold.

Toward that end he proposes new ideas for managing the dam. One would be to release water from two bypass tunnels that usually only operate when the reservoir gets so full that it’s dangerously close to overtopping, or when managers intentionally boost flows for environmental reasons.

Show caption Hide caption The Colorado River has suffered through mostly dry winters since the turn of the 21st century, offering less springtime snowmelt to refill Lake Powell than... The Colorado River has suffered through mostly dry winters since the turn of the 21st century, offering less springtime snowmelt to refill Lake Powell than Glen Canyon Dam’s engineers had counted on. The reservoir now sits about half empty, and the dam’s hydropower water intake is closer to the warm surface. The turbines now churn and release warmer water than when the reservoir was full. Michael Chow/The Republic

Those tunnels are 100 feet deeper in Lake Powell’s cold depths. They would release colder water, but at a cost because that water wouldn’t flow through generators to produce electricity.

He suggests building new generators inside the tunnels. The Bureau of Reclamation estimates that would cost $469 million. Young argues that the project would generate money in power sales.

“We’re looking for the win-win,” Young said. “I think the payback would be pretty quick.”

If it worked it would be just one more human intervention in the river, but this time to preserve a piece of nature.

Bringing back the floods

Ecologically pure or not, the Grand Canyon remains a prize for whitewater enthusiasts who love wild places. They apply for private rafting permits and wait to hear whether they or their friends draw one.

“Man, it’s incredible,” rafter Steve Sanborn said while rowing an 18-foot inflatable raft and craning his neck to scan the towering granite gorge heading into Grand Canyon’s Phantom Ranch.

A trained stream ecologist and civil engineer from Knoxville, Tennessee, he was acutely aware of the unnaturally clear and cold water, the dam-controlled tides rising and falling nightly and the scrubby tamarisks choking out native vegetation on the banks.

On whitewater, he became blissfully focused on the maze of rocks, waves and hydraulic hazards at hand, forgetting the human touch. “When it’s go time,” he said, “there’s only one thing in your brain.”

Boaters run the Class 10 Lava Rapid in the Colorado River in Grand Canyon National Park. The Grand Canyon remains a prize for whitewater enthusiasts who love wild places. David Wallace/The Republic

On flatwater stretches, though, the river’s health vexed him.

There’s no recovering a fully natural river at this point, he said, though he hoped people who visit the Canyon appreciate what’s left of its natural components.

He could settle for “as natural as possible.”

Native fish and plants deserve a priority, he said, though the dam has its place because “everybody’s gotta drink.”

Recreation — including float trips like the one he enjoyed in May — helps people touch and understand water’s role in the environment, Sanborn said. It creates nature lovers at a time when nature everywhere is disappearing.

“We don’t have much wilderness left,” he said, “and what we have we’ve got to fight for.”

So what does he think the Canyon needs?

Looking over his shoulder at the tangles of thorny, invasive tamarisk, he imagined the pre-dam springtime floods that sometimes scoured the Canyon and encouraged reseeding of native trees.

“You gotta get some high flows in here,” he said.

Show caption Hide caption River runners stand on the banks of the Colorado River at Redwall Cavern in Grand Canyon National Park. Water releases that are meant to help... River runners stand on the banks of the Colorado River at Redwall Cavern in Grand Canyon National Park. Water releases that are meant to help rebuild beaches and sandbars in the Canyon often turn up mixed results. David Wallace/The Republic

Six times since 1996 the Bureau of Reclamation has opened Glen Canyon Dam’s bypass tunnels to simulate a flood. The waters gushed midair below the dam before landing like giant firehose streams into the river, more than tripling the regulated flow to anywhere from 36,000 to 45,000 cubic feet per second for periods ranging from one day to one week.

The river typically flows at between 8,000 and 25,000 cubic feet per second through the Canyon.

When weather-dependent conditions are right, the agency may do it again.

The purpose is to restore a sliver of the environmental services that much larger floods once provided to Grand Canyon, and to let the many agencies and organizations with a stake in the Canyon study the effects.

So far the results have been mixed. As with so many things in Grand Canyon, the tally of benefits depends on one’s desired effects.

A primary goal, especially for the National Park Service, is to push sand in the river up onto the banks to rebuild beaches and sandbars. These are the places where boaters camp, and where native vegetation may re-establish within a root’s reach of steady water.

The problem is that most of the sand that would naturally flow into the Canyon is instead piling up under the still waters of upper Lake Powell, backed up along with stored water behind the dam.

So dam managers wait for monsoon storms or other significant runoff to peel sediment out of southern Utah and push it through the Paria River to Lees Ferry, below the dam. It’s not the same as epic floods of old, which flowed two, three or more times higher than these experimental releases and carried sand from as far as Wyoming, but it’s enough to rebuild a beach.

And build it does, federal researchers have found.

Water shoots out of the turbines of Glen Canyon Dam during an experimental 5-day high-flow release to help restore beaches along the Colorado River in Grand Canyon in 2012. Rob Schumacher/The Republic

For instance, a 2012 high-flow experiment more than doubled the size of some of the park’s beaches and sandbars, especially in the reaches closer to the dam. Schmidt’s staffers from the U.S. Geological Survey at the time watched 33 sandbars with remote cameras and noted 18 of them growing substantially, 12 remaining unchanged and three eroding.

After each such flood, they’ve also watched most of the gains eroded back into the river over the following year. Rising and falling “tides” that follow hydropower demand tend to eat into the banks, requiring renewed floods to rebuild them.

The problem lately has been a lack of sand, in part because drought has limited the flash floods that scour it out of tributary streams. The last high flow was in 2016. Dam managers will consider another only if the monsoon cooperates and reloads sand from the Paria.

Where larger beaches remain, their new sand loads tend to invite vegetation that crowds out camping areas. Much of it is tamarisk, Schmidt said.

Are these floods worth the trouble and cost?

Leslie James isn’t sure. The water that flows to raise the river comes through the bypass tunnels, missing a chance to generate the power that her organization, the Colorado River Energy Distributors Association, relies on to supply users across the West.

The revenue losses equal about $2 million each time, the Bureau of Reclamation estimates, and James must find power from some other source for customers.

“The jury is out” about whether the flows enhance beaches, she said. “Some win, some lose.”

Show caption Hide caption A desert bighorn sheep grazes along the banks of the Colorado River near river mile 185 in Grand Canyon National Park. Some of the sandbars... A desert bighorn sheep grazes along the banks of the Colorado River near river mile 185 in Grand Canyon National Park. Some of the sandbars and beaches that are built up after water releases erode back into the river over the following year. David Wallace/The Republic

Schmidt uses the same words: “The jury is out.”

But he sees evidence that continuing the experiments is worthwhile.

“There is a hint in the data and the latest studies that there is a slow progressive improvement in conditions,” he said. “So I would continue (the floods).”

Park officials have no doubts that the high flows should continue.

“We have a system that was inherently sediment-intensive,” Balsom said, “and with the trapping of so much in the reservoir, our system has become starved.”

'The river will always win out'

For some who love the Canyon, occasional jolts of “nature” in the form of high flows aren’t enough.

Suz Burd, of White Salmon, Washington, is one of them. After a day of hiking and splashing through side canyons and waterfalls and bouncing over rapids on her fifth Grand Canyon river trip, she mused about how magical the place must have been before the dam.

“I feel like I was born a generation too late and didn’t get to see it,” the 61-year-old community college administrator said from her camp that evening in May.

She had spent part of the afternoon discerning turkey vultures from condors soaring overhead, and was still in awe of all the bighorns she had seen sipping from the river that week. The Canyon always challenges and rewards, she said, ever since she had first accepted a rafting invitation when her husband died in 2002.

Show caption Hide caption Suz Burd escapes the heat of the midday sun in Blacktail Canyon, a side canyon drainage of the Colorado River in Grand Canyon National Park... Suz Burd escapes the heat of the midday sun in Blacktail Canyon, a side canyon drainage of the Colorado River in Grand Canyon National Park on May 24, 2018. “I feel like I was born a generation too late and didn’t get to see it,” Burd says of the Canyon before the Glen Canyon Dam was built. David Wallace/The Republic

“What keeps me coming back is the big medicine that this place is,” she said. “Spiritual medicine.”

She longed for a day when the river runs at its own pace, untamed by Glen Canyon Dam. She may not see it in her lifetime, she acknowledged, but younger generations may figure better ways to get their electricity. “Solar doesn’t harm fish,” she said.

Over time, she believes, the dam is unsustainable.

“The river will always win out,” she said. “I hope.”

Some environmentalists and river runners have always dreamed of removing the dam and letting Glen Canyon breathe again. The dreams remain such largely because water managers have always insisted that the reservoir’s top jobs – storing water for use in later dry years – has only grown in importance over the decades that the Southwest has led America’s population growth.

Yet just as the punishing drought has apparently warmed waters to the liking of native fish, the falling water line has breathed life into a proposal that would uncover at least parts of the sunken canyon.

Some environmentalists now advocate a “Fill Mead First” solution, which would leave the dam in place but largely drain Lake Powell and let the water flow through Grand Canyon to prop up Lake Mead below.

They believe this would reduce losses of standing water from seepage into Glen Canyon’s sandstone, and that Lake Mead could handle the amount of water likely to be available in a regional climate that is increasingly drier and warmer than the dam’s builders had expected.

Show caption Hide caption River runners scout the Class 9 Hermit Rapid of the Colorado River from atop a rocky outcropping in Grand Canyon National Park. Some environmentalists and... River runners scout the Class 9 Hermit Rapid of the Colorado River from atop a rocky outcropping in Grand Canyon National Park. Some environmentalists and river runners have advocated for removing the dam and letting Glen Canyon breathe again. David Wallace/The Republic

The Glen Canyon Institute, a Salt Lake City-based group pushing for restoration of the canyon and a free-flowing river, argues extended drought only makes the dam’s folly more obvious. Its advisory board includes former Reclamation Commissioner Dan Beard, whose 2015 book “Deadbeat Dams” advocates water policy reforms including Glen Canyon Dam’s removal.

“It seems every new climate study projects the shortage trend will become more intense,” Glen Canyon Institute Director Eric Balken said, “and we believe it’s imperative to study every possible option to deal with it.”

The institute has proposed drawing down Lake Powell in stages that would culminate in the construction of new bypass tunnels allowing the water to flow at the river’s natural level, exposing the buried canyon above. The dam would remain in place and could be used again if there’s a future wet era.

Reclamation and an interagency committee recommending dam management have so far declined to study the idea in depth. Balken suggests it’s a matter of time.

“If the trends continue,” he said, “we’ll have to figure out how to deal with a low Lake Powell anyway. Why not study (Fill Mead First) now and figure out how to make the most of this new normal for the benefit of Grand Canyon and Glen Canyon?”

If spreading the water between two reservoirs has evaporated more of it or lost more to sandstone aquifers, current science is unsettled on the point.

The institute commissioned a study five years ago that estimated the yearly losses at 300,000 acre-feet, the total allocation for the state of Nevada.

But Schmidt, the Utah State professor and former Grand Canyon Research and Monitoring Center chief, reviewed existing data and literature and concluded the likely number is in the range of 30,000 to 50,000.

Show caption Hide caption Some environmentalists advocate a “Fill Mead First” solution, leaving Glen Canyon Dam in place but largely draining Lake Powell and letting the water flow through... Some environmentalists advocate a “Fill Mead First” solution, leaving Glen Canyon Dam in place but largely draining Lake Powell and letting the water flow through Grand Canyon to prop up Lake Mead below. They believe this would reduce losses of standing water from seepage into Glen Canyon’s sandstone, and that Lake Mead could handle the amount of water likely to be available in a regional climate that is increasingly drier and warmer than the dam’s builders had expected. Michael Chow/The Republic

The water’s location — Lake Mead or Lake Powell — hardly affects evaporation, he found. Lake Powell has a larger surface area to invite evaporation, but in Lake Mead’s climate, the water generally evaporates more in a given surface area.

The small difference in expected water loss comes in potential seepage into the sandstone, where Schmidt studied data from a sampling of test wells near Page in the 1980s. The government should drill and monitor more wells to make a better prediction, he said.

“You’ve got a zillion unknowns,” Schmidt said. For now, 50,000 acre-feet seems to him a relatively small justification for draining Lake Powell.

The Interior Department declined to consider “Fill Mead First” or dam removal when it approved a 2016 adaptive management plan authorizing experiments and setting flow parameters for the next 20 years.

Draining Lake Powell, Interior officials wrote, “would not allow compliance with water delivery requirements” or meet the terms of other regulations and laws.

Even environmentally it could cause problems for Grand Canyon, Schmidt said. Only the dam's bypass tunnels would funnel water downstream, eliminating the possibility of a planned flood to move sediments.

That doesn’t mean the government should stand pat, he said. Like Balken, he suggested that the drought and changing climate may some day drain the reservoir on its own, and the region should be ready with well-researched options.

“In a brave new world that’s coming at us in the future with a significant decrease in runoff,” he said, the Bureau of Reclamation needs to know what it will cost to bore new tunnels that would allow the river to continue running instead of pooling at the dam’s base without rising to the existing outlets.

The time for these studies is now, Schmidt said, especially if Colorado State University water researcher Brad Udall and colleagues are right that warming will sap up to 20 percent of the river’s flow by midcentury and 40 percent by 2100.

Those predictions are based on projected greenhouse gas emissions using the world’s current energy trends, and on research into how temperature affects vegetation.

The sun sets over the Colorado River in the western part of Grand Canyon National Park. David Wallace/The Republic

Udall — whose uncle, Stewart Udall, was the U.S. Interior secretary who oversaw Glen Canyon Dam’s construction — warned a group of Colorado River reporters on an Institute for Journalism and Natural Resources tour that global warming is both reducing the river’s snowpack source and increasing demands by thirsty trees and plants.

“Climate change is water change,” he said.

The losses could reduce our options and magnify the effect of dam management on Grand Canyon ecology. Some human values will win, and some will lose.

“We’re now playing God in these ecosystems,” Udall said. “We should own up to it.”

On the side of nature

Jerry Gunn sees a brighter future for the Canyon and his business, if federal resource managers intervene on the side of nature.

The owner of a Lees Ferry trout-guiding service predicts the introduction of mayflies, stoneflies and caddisflies will be the biggest environmental shock to the river since the dam went up.

It could be that the bug flows — those steady weekend releases that the government tested this year — will improve conditions enough to invite the bugs to migrate here. Even with ideal conditions such a migration could take years or decades.

After 35 years on the river, Gunn prefers an immediate fix. Much as the National Park Service reintroduced wolves to Yellowstone, he likes the idea of a bug transplant in Grand Canyon.

Brad Hillgren casts a line on the Colorado River from Lees Ferry near Marble Canyon. Some fishing enthusiasts think the introduction of insects such as mayflies, stoneflies and caddisflies could help improve the river's health. Michael Chow/The Republic

“A lot of us longtime river people have been talking about it for years,” he said. “We think it would be an incredible science project.”

The dam may have altered the habitat such that the Canyon’s previous insect complement couldn’t take hold, he said. In that case there are many species of the three targeted flies, some of them living in abundance upstream on the Green River. Gunn hopes trial-and-error could determine which can survive the river in Grand Canyon.

It’s not just about the trout.

“The environment has everything to gain,” Gunn said. “It’s going to benefit native fish. It’s going to benefit bats. Amphibians are going to love it. Ducks. It’s a win-win for everyone.”

Public officials aren’t there yet.

“We have to think of unintended consequences,” said Balsom, the national park stewardship chief. She said efforts to control non-native tamarisk trees by introducing non-native beetles to eat the leaves has threatened to wipe out nesting places for some rare birds.

Park crews have helped move chubs to new waters within the canyon, she said, but only after careful research and clear evidence that they once belonged there.

It turns out there is no consensus that mayflies or stoneflies ever belonged in the canyon.

Larry Stevens, a conservation biologist with the Museum of Northern Arizona and senior ecologist with the Grand Canyon Wildlands Council, believes his research indicates mayflies and stoneflies never could thrive in the upper canyon.

Caddisflies – rare to usually non-existent near the dam and Lees Ferry – are curiously showing themselves on the river in the western Grand Canyon for the first time in Stevens’ 45 years of studying here. One theory is that the unnaturally clear water that the dam releases encourages algae growth by allowing sunlight to hit the river floor in stretches downstream of the canyon’s shadowy inner gorge.

But his comparison of the cold tributary stream in the park’s Tapeats Creek — “loaded” with mayflies, stoneflies and caddisflies — to conditions in the river it joins suggests that this stretch of the Colorado doesn’t have the right habitat for mayflies or stoneflies even with steady flows for egg hatching.

Stevens and colleagues suspended baskets of rock and gravel in the river near the mouth of Tapeats Creek but far enough to be in a zone not frequented by the creek’s flies. They soon found the flies crawling between the rocks, regardless of the river’s fluctuating flows.

Show caption Hide caption Biological science technician Brece Hendrix holds a bug trap that was placed on the banks of the Colorado River near Marble Canyon. There's no consensus... Biological science technician Brece Hendrix holds a bug trap that was placed on the banks of the Colorado River near Marble Canyon. There's no consensus on whether mayflies or stoneflies ever belonged in this part of the Canyon. Michael Chow/The Republic

The lesson: The aquatic insects that so rarely swim or buzz the Colorado in the Grand Canyon could thrive there if cobble and gravel covered the riverbed. But the river here courses mostly over sediments and embedded boulders, with few nooks and crannies in which these insects could hide.

“There’s no gravel,” Stevens said, “and there never has been.”

It could take at least a decade of weekend “bug flows” for new species to arrive at Lees Ferry on their own, said Kennedy, the USGS biologist. He wants to know how they respond downstream before considering a transplant to Lees Ferry.

Like trout guide Gunn, though, he thinks a boost to the canyon’s bug numbers and diversity would be a natural “win-win.”

“A rising tide floats all boats,” he said. “We may create more trout, but also more chubs.”

Surprises around every turn

As warped as Grand Canyon’s river ecology is today, it arguably used to be weirder.

These days the Bureau of Reclamation considers the park, the fish, the river runners and others before turning the crank to power up the generators. Its routine daily flows fluctuate no more than 8,000 cubic feet per second — enough to raise the river by a couple of feet, but a limit where years ago there was none.

Canyoneer Rich Rudow remembers a “free-for-all” when he first floated and hiked the canyon in the late-1980s, with waters rapidly rising by 40,000 cubic feet per second. Picking a riverside campsite was a risk.

Rudow, a Phoenix-area resident, now has spent more than 1,000 days below Grand Canyon’s rim, most of them exploring the side canyons that remain largely unchanged by the dam. From atop a sandstone precipice on the park’s Deer Creek last spring, he said he prefers wild tributaries like the one tumbling into that slot canyon. They’re primeval, or more so than the weirdly aquamarine Colorado below, where a ruddy river should flow.

“You’re seeing the natural ecosystem” in a side canyon, he said. “It’s been in this state for eons.”

As he spoke, two finger-length lizards, apparently locked in combat, fell from a rock overhead and thumped against his ballcap. One plopped to the ground and the other sat dazed on his brim.

Members of a private river trip push a boat that got stuck in the mud after the Colorado River receded overnight at the campsite above Soap Creek rapid in Grand Canyon National Park. David Wallace/The Republic

These moments with the canyon’s creatures and silences, its weather and its brilliant nighttime Milky Way views, keep him returning to a place he considers wild if not natural. “I’m saddened to some degree because people don’t know how it was.

Still, “This is probably the last great wild place in the Lower 48,” Rudow said. “This is the crown jewel of the National Park Service.”

A similar sentiment drives many others with deep roots in the canyon, including the scientists who study it in hopes of saving the parts that still can be saved.

Stevens, the Grand Canyon Wildlands Council ecologist, puts the canyon’s importance in global terms, alongside disappearing rhinos and tigers. What’s left of Grand Canyon’s natural systems, in arguably the world’s most-recognized park, stands alongside those icons for conservation.

“They’re archetypes for all of humanity,” he said. “Each of us needs to take personal responsibility for those losses.”

His organization has worked to restore native vegetation by cutting tamarisks in the side canyons that drain into the Colorado. The side canyons are among the most isolated and natural areas of the West, and Stevens fears the quagga mussels spreading in Lake Powell or an expanding crayfish invasion could spoil them.

Mallards never bred at Lees Ferry, until a few years ago, he said. Then bald eagles showed up and started feeding on trout. A couple of years ago non-native green sunfish appeared, to the alarm of park biologists.

There’s no telling how many more changes Glen Canyon Dam may yet have in store for the river.

“We’re 55 years into this experiment,” he said, dating to the dam’s construction. “There are still surprises around every turn, every year.”

Schmidt, the former chief of Grand Canyon monitoring, said he hopes for a "new kind of river science" that can help predict how changes in flow and temperature will affect fish and other resources.

He also hopes the states that rely on Colorado River water will begin to see Lake Powell and Lake Mead as one — a "reservoir in two parts connected by a scenic bedrock ditch" — instead of treating one as the storehouse for upper-basin states and the other as the lower basin's supply.

That would help create flexibility to release flows that maximize environmental conditions rather than worrying so much about keeping one or the other of the reservoirs at a set elevation.

Show caption Hide caption Eric Luth wades through water in the redwall narrows of a side canyon of the Colorado River in Grand Canyon National Park. Hundreds of side... Eric Luth wades through water in the redwall narrows of a side canyon of the Colorado River in Grand Canyon National Park. Hundreds of side canyon drainages meet the Colorado River in Grand Canyon and offer a glimpse into something not impacted by Glen Canyon Dam. David Wallace/The Republic

Van Haverbeke, the chub biologist, said he hopes more people will visit the canyon and care about its future — same as the future of water management in the Southwest.

"Learn to respect nature in the first place, and have some respect," he advised. "Then when you can do something (to help), you'll actually maybe do it."

As biologist Daubert throttled her boat onto a grassy bank a dozen miles downstream from the dam, midges clouded the view of the orange cliffs above. She was after a trap that turned out to contain hundreds or thousands of the tiny insects.

She couldn’t say why this stretch of grass and tamarisk would draw a swarm denser than the last one had.

“Sometimes it’s here,” she said, “and sometimes it’s not.”

She hoped the experimental steady weekend flows would help these insects so that on her next outing she would find more stuck to the sticky traps or floating in the antifreeze dish.

The river’s health starts from the bottom, she said, with the fish food. Americans have used the water without often considering the effects, but the bug flows are a chance to manage it thoughtfully.

“If you take, you give,” Daubert said. “We’ve taken so much from the Colorado River.

“We need to do something and keep it healthy.”

Colorado River, unnatural resource: How we did the story Arizona Republic photographer David Wallace talks about his 226-mile, 16 day trip down the Colorado River in Grand Canyon. David Wallace and Michael Chow/The Republic

Environmental coverage on azcentral.com and in the Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust. Follow the azcentral and Arizona Republic environmental reporting team at OurGrandAZ on Facebook, Twitter and Instagram.