At 8 a.m. Tuesday, there was only silence and the occasional crunch of rocks as a dozen people in orange vests waited in a moonlike landscape beneath a 350-foot-tall dam near Loveland.
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“Ninetey seconds,” a worker called out.
Moments later, it sounded like a waterfall suddenly roared to life as Northern Water started filling Colorado’s newest reservoir, Chimney Hollow.
“It's pretty cool, I mean it's something we've been working on for a long time, so just to see it for real, it’s pretty cool,” Chris Manley, a water quality specialist with Northern Water, said as he watched water gush from a 40-foot-tall concrete tower at the bottom of the reservoir.
By the end of the week, the initial release of 1,500-acre feet of water will rise about 30 feet above the spot Manley and a gaggle of journalists were standing on Tuesday morning.
Engineers will make sure the pipes that will funnel Colorado River water to the reservoir are functioning correctly. It will also give Northern Water a chance to study an issue with the water supply.
The reservoir’s future became murky last year after officials announced that naturally occurring uranium was found in the rock used to build the dam for the reservoir.
Manley said the uranium discovery has set the project back roughly a year. But he said it is an issue Northern Water can manage long term.
“But we've got to really understand the situation a lot better before we can move forward,” he said.
This week’s initial fill will provide Northern Water with a real-world test of the water quality that was only previously done in laboratories.
None of the water coming into the reservoir will be released to taps at this point. The reservoir is only being filled to about 2% of its total capacity in the coming days.
“We'll be measuring it actually pretty frequently, to see just what is (the water) picking up as it goes up and touches the dam and starts to move some of the sediments around here,” Northern Water spokesperson Jeff Stahla said.
Northern Water officials could not provide a timeline for when water will begin reaching the dozen water suppliers who have signed up to receive it.
The reservoir project cost an estimated $500 million and has been in the planning stages for more than two decades.
Conservation groups have raised concerns about the reservoir.
Jen Pelz, wild rivers program director at the conservation group WildEarth Guardians, told KUNC in 2022 that the project would burden a Colorado River water supply that is already overallocated.
"You can have a bunch of buckets, and you can build more buckets to put water on the front range," Pelz said. “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 reservoir is seeing its initial fill during historic drought conditions in the Colorado River basin.
It also happened a day after Denver Water announced it would drain Antero Reservoir near Fairplay to conserve water this summer and minimize evaporation.
“It's definitely very ironic that we're filling the reservoir in these historic drought conditions, but we're fortunate that we had a little bit of supply left from last year,” Northern Water Operations Director Jerry Gibbens said. “It really showcases why storage is so important for our region.
Northern Water officials say the reservoir is a way to boost water security on the Front Range.
“As we've seen this year, water storage is such a key element of our overall water supply in northern Colorado, and this just adds another increment of that supply to a region where our water demands continue to grow,” Stahla said.
