5 days Ago By Elise Schmelzer
Denver Water will forge ahead with construction on its $531 million project to raise Gross Dam despite the threat of ongoing litigation that could derail the massive reservoir expansion — one that utility leaders say is critical for future water security.A federal appeals court ruled late Friday that Denver Water could continue construction until further notice while it considers the utility’s request to review a lower court’s order blocking the project. The state’s largest utility — which provides water to 1.
5 million people in metro Denver — will begin pouring concrete for the new section of the dam as soon as possible, Denver Water leaders said.Crews have been called back to work amid the shifting directives from the courts, but there’s still a cloud hanging over the project, Denver Water CEO Alan Salazar said.“Even though we’ve got the green light,” he said, “it would be the wrong impression to say that we didn’t lose some momentum and still have some challenges.
”More than two decades in the making, the project now stands at a crossroads, pitting abstract environmental law and court proceedings against the concrete reality of a half-built, half-billion-dollar dam.A federal district court judge on April 3 ordered Denver Water to stop dam construction and blocked the expansion of the reservoir after earlier finding that the environmental permitting process underlying the project was flawed. The order — followed by the judge’s granting of a brief window to complete necessary work — forced Denver Water to send hundreds of workers home from the construction site outside of Nederland.
Expanding Gross Reservoir is critical to add water storage capabilities on the north end of the utility’s water supply system and to create more of a safeguard in case the much larger south end of the system becomes impaired, according to Denver Water. Construction began in 2022 and, if finished as planned, Gross’ capacity would nearly triple to 120,000 acre-feet and become Denver Water’s second-largest reservoir.The project would make the structure the tallest concrete dam built in the United States in more than 50 years.
Environmental groups for years have fought the reservoir expansion, arguing that Denver Water could have pursued less-damaging options. The expansion requires the chopping down of about 500,000 trees and will siphon water from the already-shrinking Colorado River.The groups plan to continue fighting the project in court and to urge the courts to uphold the federal district judge’s injunction against the project, said Gary Wockner of Save the Colorado, the lawsuit’s lead plaintiff.
There should be penalties for breaking the law, he said.“If someone is robbing a bank and you say, ‘That’s against the law but we’re not going to stop you,’ then everyone is going to go rob a bank,” he said.Since the April 3 ruling blocking the project, Denver Water leaders have struck a defiant tone.
They’ve called the decision “deeply flawed,” “radical,” “appalling” and an “egregious example of how difficult it has become to build critical infrastructure in the face of relentless litigation and a broken permitting process.”Jeff Martin, program manager for Denver Water’s Gross Reservoir Expansion Project, expresses concern about safety risks if the project is left unfinished, in Boulder County, Colorado, on April 9, 2025. (Photo by RJ Sangosti/The Denver Post)“The reason we’re here doesn’t make sense,” Jeff Martin, Denver Water’s program manager for the reservoir expansion project, said last week at a news conference at the base of the partially constructed dam.
“It doesn’t make sense to our ratepayers, it doesn’t make sense to Denver Water. We’re caught over a war of words right now.”“We’re going to end up building this to the top and having a secure water supply,” he added.
$450 million spent so farEven before Friday’s decision by the 10th U.S. Circuit Court of Appeals, workers walked the layers of scaffolding climbing the 340-foot dam.
The crews were scheduled to begin pouring concrete later in the week to add the new 131-foot vertical extension of the dam until the federal court order blocked their work.That order, by U.S.
District Court Judge Christin Arguello, prompted the utility to send hundreds of workers home, Martin said. He has since called the workers back and hopes to begin pouring concrete as soon as possible, but the pause and ongoing litigation cast doubt on job stability for the 350 workers recruited from across the country, he said.“We’re proceeding as if we can build the dam in the future,” Martin said, as a massive crane behind him lugged equipment from the dam base to its top.
The appeals ruling extended a 14-day window Arguello had granted on April 6 for Denver Water to continue construction while it filed its appeal.Already, the utility has spent $450 million on the project — $330 million of which has gone to construction costs, Martin said.A delay to construction would cost at least $50 million, according to Denver Water’s appeal.
A longer pause may force the utility to lower the water level in the reservoir even more to reduce pressure on the unfinished dam, which would “further threaten the precarious water supply in areas Denver Water serves.”Denver Water’s Gross Reservoir expansion project in Boulder County, Colorado, on April 9, 2025. (Photo by RJ Sangosti/The Denver Post)Martin said the partially completed dam was not structurally safe for the long term.
Crews spent three years deconstructing the original dam to prepare to raise it, he said, and they’re concerned about how the unfinished structure would handle a flood.Arguello scheduled a May 6 hearing so Denver Water could explain what kinds of construction must still be completed to render the dam structurally sound.Engaging in a war of wordsA one-two punch of extreme drought and disastrous wildfire in 2002 sparked the Gross Reservoir expansion project.
The drought drained the utility’s reservoirs, forcing its leaders to impose mandatory watering restrictions. And the Hayman fire ripped through the forest surrounding much of Denver Water’s southern system — which supplies approximately 80% of the utility’s water — sending tons of sediment into pipes and reservoirs and making water delivery difficult.Denver Water developed the Gross Reservoir expansion project in the wake of the disasters of 2002 to increase water storage and create system redundancy.
If completed to plan, the Gross Reservoir expansion will increase Denver Water’s total storage by 11% and storage in the north system by 146%.Critics of the project said the expansion was unnecessary, with less-damaging alternatives available. Incentivizing water conservation practices like removing turf would be cheaper and better for the environment, said Mark Squillace, a University of Colorado water law professor who is not involved in the lawsuit but has criticized the project for years.
Denver Water customers’ total water use has remained relatively level even as the number of people served has more than doubled, data from the utility shows. Continuing that trend would erase the need for an expanded reservoir, Squillace said.“It would be a lot cheaper to provide programs to people to xeriscape their lawns or plant some other low-consumption plants that don’t use so much water,” he said.
“There are things that were not explored and, given the cost of the project, it was irresponsible to not explore these opportunities.”Denver Water customers will pay for the reservoir expansion for years. This year, the project meant the utility needed to raise revenue by 3.
5% — translating to an annual increase between $21 and $27 for an average customer, according to the utility.The utility’s leaders defend the project and say the utility has spent $30 million across dozens of projects to offset the environmental impacts of the reservoir expansion, including stream restoration on the headwaters of the Colorado River. The utility also transferred 500 acres of land near the Indian Peaks Wilderness to the U.
S. Forest Service to compensate for the acres to be drowned by the expanded body of water.Denver Water’s Gross Reservoir expansion project in Boulder County, Colorado, on April 9, 2025.
(Photo by RJ Sangosti/The Denver Post)Its leaders agreed to build the dam six feet higher so that the reservoir had enough space to store 5,000 acre-feet of water to be used for environmental health purposes on South Boulder Creek, which flows out of the bottom of the dam. That commitment cost upwards of $30 million, Martin said.“We’ve already completed all of our mitigation projects for this project, in a good faith showing that Denver Water is an environmental steward — and the environmental aspects of this project are as important as any other aspect for us,” he said.
Deadlines and Colorado River impactBeyond debating the project’s merits, both sides point fingers at each other for the timing of the legal issues, which came to a head after construction began and hundreds of millions of ratepayers’ dollars were already spent.The plaintiffs accused Denver Water of jumping the gun on construction before the litigation was settled — an argument Arguello agreed with in her ruling.“I think that Denver Water made a mistake,” Squillace said.
“They thought they could bully their way into completing this project before anyone could get an injunction against them, and they were wrong.”But in its appeal, Denver Water shot back and questioned why the environmental groups didn’t ask for an injunction on construction before work began in 2022.The environmentalists first sued in 2018 but the case was dismissed in 2021.
The groups appealed that dismissal and, in 2022, a judge ruled that they could proceed with their challenge of the project, which resulted in a renewed fight beginning in September 2023.Denver Water also had to comply with an order by the Federal Energy Regulatory Commission to begin construction by 2022 and finish by July 16, 2027.The utility’s leaders did not ask the commission for an extension of those deadlines, said Jessica Brody, its general counsel.
Denver Water had the required permits to proceed and — without a request from plaintiffs for an injunction — it had the obligation to start construction, she said.“We knew the costs would only escalate if we waited,” Brody said.Since Arguello’s ruling, she said, Denver Water has not explored the option of asking the commission for an extension on the 2027 deadline.
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