
Judge nixes Army Corps dredge-and-fill permit for Denver dam
Amanda Pampuro
DENVER (CN) — A federal judge on Thursday found the U.S. Army Corps of Engineers violated the Clean Water Act and the National Environmental Policy Act in issuing a dredge-and-fill permit to Denver in 2018 allowing the city's utility to begin construction on what will become the state's largest dam.
"The Corps inappropriately framed the proposed action’s purpose-and-need statement, which unduly constrained the definition of ‘practicability,’” wrote Senior U.S. District Judge Christine Arguello in an 86-page opinion. “That strategic choice wholly relieved the Corps of its burdens to explore and discuss certain alternatives to enlarging the Gross Dam and Reservoir."
Challenging a 2017 record of decision in which the federal government issued permits without adequate environmental review of the proposed Gross Dam and Reservoir project, Save the Colorado joined five other environmental groups in suing the Army Corps and the Department of Interior in December 2018.
In a 2002 integrated resource plan, Denver anticipated water demand 50 years into the future and raised concerns about demand outpacing supply as early as 2016, prompting a 2003 permit application to expand Denver’s Moffat Collection System which supplies Gross Dam.
Today, Denver Water serves 1.5 million people and anticipates needing 18,000 acre-feet per year of new firm yield. In addition to needing more water, Denver also sought to make its overall system more efficient, as it pulls water from two separate sources.
By diverting water from the Colorado River on the Western Slope of the Rocky Mountains and storing it in the Gross Reservoir on the Eastern Slope, the utility sought to shore up shortfalls in its northern system, which currently only reaches 10% of customers. The project will also allow the Moffat Water Treatment Plant to run year-round and through anticipated periods of droughts.
The project involves the construction of the tallest dam in the state and will result in 500,000 felled trees, as well as 1.6 million tons of rock removed, and incalculable risks to local fish.
Arguello, a George W. Bush appointee, initially granted the government's motion to dismiss in 2021 citing lack of subject-matter jurisdiction. The environmental groups appealed, and the 10th Circuit revived the case in 2022.
Arguello held a bench trial on Sept. 20, six years after the filing of the initial complaint, though the construction is underway with a projected completion date in 2027.
"The debate over the Gross Dam and Reservoir expansion proposal is both public and passionate,” Arguello wrote. “The administrative record makes abundantly clear that a plethora of stakeholders in the Colorado River and Front Range’s water resources are deeply concerned about any proposal that tampers with the region’s already precarious water management system and uncertain hydrological future.”
In a footnote, Arguello further placed the Gross Dam and Reservoir project as a tributary on the larger, turbulent struggle to reimagine Colorado River water allocations so that it remains a sustainable water supply for the West, where it nourishes 40 million people and waters 5.7 million acres of crops.
Save the Colorado additionally claimed the U.S. Fish and Wildlife Service wrongly withdrew protections for a species of cutthroat trout believed to be related to the endangered greenback cutthroat trout. During the decade-long plan review process, however, government scientists found evidence that the Boulder fish were not as closely related to the endangered species as previously thought and therefore did not warrant the same protections. Arguello found the agency’s reasoning passed scrutiny on that claim.
Rather than outright vacating the permit with the dam project under construction, Arguello requested the parties file remedy briefs within a month and work in good faith toward a mutually acceptable solution.
A spokesperson for Denver Water emphasized the need to continue moving forward with the project to meet federally required deadlines and build climate change resilience.
“What remains clear is the critical nature of the Gross Reservoir Expansion to the Denver region in an era of climate change,” Denver Water spokesperson Todd Hartman said via email.
Hartman pointed to 2002, when drought and wildfire threatened the utility's ability to provide water to northern customers, while increased sediment posed challenges to the southern system.
“The expansion of Gross Reservoir is intended to prevent such a dire threat from presenting itself again,” Hartman said. “Throughout the permitting process, Denver Water has been driven by a singular value: the need to do this expansion the right way, by involving the community; upholding the highest environmental standards; providing a sustainable, high-quality water supply to our customers; and protecting and managing the water and landscapes that define Colorado.”
A representative from the U.S. Department of Justice declined to comment on the opinion.