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Throughout the history of the American West, water issues have shown their ability to both unite and divide communities. As an imbalance between water supplies and demands grows in the region, KUNC is committed to covering the stories that emerge.

What does it take to build a massive new reservoir? A lot of time, trucks, and rock

An excavator can be seen against a backdrop of brown cliffs.
Alex Hager
An excavator moves dirt while building the new Chimney Hollow reservoir, part of an effort to move about two million cubic yards of earth. The project will take four years to complete, then three more years to fill with water. It's designed to help store water for homes in rapidly-growing cities along Colorado's Front Range.

On its way to your kitchen faucet, water in the Colorado River basin takes a long and winding journey. High mountain snowmelt trickles through streams, rushes through rivers, and flows along a chain of man-made tunnels, canals and reservoirs before it even reaches city pipes.

For tens of thousands of people on Colorado's Front Range, that journey will soon involve another step, as the Chimney Hollow reservoir takes shape in the hills above Loveland. Proponents of the build say it's an investment in the future of a growing Colorado, while critics say it will add strain to an already taxed watershed.

The build itself is a feat of engineering, and a striking example of human ability to reshape the natural world.

Right now, Chimney Hollow is a project site teeming with activity. Building a reservoir involves far more than just digging a hole in the ground. At this particular spot, it requires the construction of a massive dam – the tallest built in the United States in 25 years.

"Seeing it on plans and seeing pictures of it doesn't really do it justice until you're here standing at the bottom, looking up 350 feet to the top of the dam, a hundred feet below where original ground was," said Jeremy Deuto, Chimney Hollow's project engineer.

PHOTO2 Joe and Jeremy
Alex Hager
"Seeing it on plans and seeing pictures of it doesn't really do it justice," said project engineer Jeremy Deuto (right). He and project manager Joe Donnelly look on as dump trucks shuttle excavated earth out of the soon-to-be-reservoir.

To build something at this scale, machines are moving a volume of earth that’s hard to wrap your head around.

"We're filling 100-ton trucks," said Joe Donnelly, Chimney Hollow’s project manager. "We need a whole load of rock placed on the dam every two minutes, five days a week, for two and a half years."

In a state where "feeling small" often comes at the hands of eons-old mountains, or a vast expanse of blue sky, it's an odd sensation to be dwarfed by something far less natural. In this case, an excavator. Shoveling heaps of dirt into a waiting dump truck with tires twice the height of a person, this excavator could dig the foundation of a house with just three scoops.

Each gargantuan yellow vehicle contributes to the ordered chaos — a maelstrom of whirs and croaks and beeps as the earth is reshaped according to a carefully planned blueprint. It's hard to see the bigger picture from the bottom of the soon-to-be reservoir, but a perch from high above provides a sweeping view of the gestalt.

Up here, with the noisy work below reduced to a gentle din, Jeff Stahla, a spokesman for Northern Water, explains the reservoir will wrap around the cliffs we're standing on and extend past our field of view.

Chimney Hollow wide above
Alex Hager
Viewed from above, the future Chimney Hollow reservoir is a network network of roads, dig sites and dam construction. When it’s finished, the reservoir will provide water to thousands of people in towns such as Broomfield, Loveland, Greeley and Longmont.

"When you build a dam of this size," he said, "You're not thinking of something that's going to happen just in a few months or a year to address your needs just a few years down the road. You're thinking generationally."

That generational thinking helps explain why the project is such an undertaking. When it's finished, the reservoir will provide water to thousands of people in towns such as Broomfield, Loveland, Greeley and Longmont. It's taken about two decades to get the build permitted, and it'll be four more years of construction and then three more years of filling before the reservoir is completed. The total cost comes to about $500 million, breaking down to roughly $340,000 for each day of construction.

PHOTO3 Dump Trucks.jpg
Alex Hager
The fleet of machinery used to build the dam and reservoir at Chimney Hollow includes huge dump trucks. The project's total cost comes to about $500 million, breaking down to roughly $340,000 for each day of construction.

Stahla said additional water storage will help water providers gain some certainty and more smoothly supply homes across the fluctuation of wet years and dry years — a practice baked into water projects for centuries.

"We're just like humans all over the planet looking to time water release in addition to storing it," he said. "So this piggybacks off of what we have, as a species, been doing all over the world. It's just interesting that a lot of us don't get to see it on this scale in the course of our lifetimes."

"There's going to be no water to fill those buckets"

Although the new reservoir has received construction permits and is now on the doorstep of becoming a reality, the path to doing so was lined with opposition. Farther upstream, critics of the project characterize it as another piece of overdevelopment in the region and an additional burden on a dwindling water supply that shouldn't be stretched even thinner.

"You can have a bunch of buckets, and you can build more buckets to put water on the front range," said Jen Pelz, wild rivers program director at the conservation group WildEarth Guardians. "But the reality is, if the projected climate change impacts come to fruition — which all indications are, they're coming to fruition quicker than we even thought — there's going to be no water to fill those buckets."

The Colorado River basin is under a level of strain it hasn't experienced in more than a millennium, with drought driving supply down and population growth driving demand up. Scientists have outlined a grim future for the region, predicting that human-caused climate change will shrink the West's water supply.

Colorado was built on a system of moving water around. About 80% of Colorado's water falls on the western side of the mountains, but about 80% of the state's people live on the east side. For a century and a half, those people have relied on a complex system of canals and tunnels that shuttle water across and through the mountains — often to reservoirs that store it for timed release.

Chimney Hollow Cliff bend 2
Alex Hager
The sprawling Chimney Hollow reservoir will fill much of this valley, wrapping beyond the field of view shown here. Critics say new water infrastructure like this reservoir will add strain to an already taxed watershed.

While that system has been a pivotal part of Colorado's existence as we know it, Pelz opposes the development of most new projects because the facts of climate change have put their functionality into question.

"I think that spending a bunch of money on a reservoir when you don't have the water to fill it is kind of silly," she said. "I heard someone have had a great quote around 'A refrigerator that's empty doesn't do a lot of good to solve someone's hunger crisis.'"

Opposition to the Chimney Hollow reservoir also came from those near the lakes and rivers that will someday be rerouted to fill it. In Grand County, Colorado, opponents argue that reducing water levels of nearby rivers and lakes could cause algae blooms and jeopardize recreation business in the mountains.

"When is enough enough?" asked Ken Fucik, vice president of the Upper Colorado River Watershed Group. "When are we going to say every drop of water that is up here will go down to the Front Range? You can't continue to add population without providing them water, we all recognize that. But where's that water going to come from? There's only so much. We are a finite resource."

Chimney Hollow user map
Northern Water
This map shows the location of Chimney Hollow reservoir and the communities it will serve. Storage is measured in acre-feet. An acre-foot is the amount of water needed to fill one acre of land to a height of one foot. One acre-foot generally provides enough water for one to two households for a year.

Fucik, a retired environmental consultant, also contends that the region's shrinking water supply has made new projects ill-advised.

"We don't live back in the 20s when there were small populations and there was plenty of water," he said. "Our biggest question to the people that make these decisions is, 'Do you even know how much water is available?'"

Back on the more populated side of the mountains, the reservoir's developers say it'll be a pivotal tool in sustaining communities and lifestyles as they're known today.

"If we're going to be able to exist and offer the same opportunities to our children and grandchildren on the Front Range," said Jeff Stahla with Northern Water, "We should consider — and we're doing it here — capturing the water when it's available so that we have flexibility in those years when we don't have it."

This story is part of ongoing coverage of water in the West, produced by KUNC in Colorado and supported by the Walton Family Foundation. KUNC is solely responsible for its editorial coverage.

Alex is KUNC's reporter covering the Colorado River Basin. He spent two years at Aspen Public Radio, mainly reporting on the resort economy, the environment and the COVID-19 pandemic. Before that, he covered the world’s largest sockeye salmon fishery for KDLG in Dillingham, Alaska.
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