PEAK TO PEAK — The 10th Circuit Court of Appeals issued a ruling on September 15, 2026, siding with Denver Water (denverwater.org/tap/federal-court-ruling-clears-way-completion-gross-reservoir-expansion-project) and reversed an injunction by the District Court that prevented the water utility from finishing the expansion of Gross Reservoir.

Denver Water is can now proceed with removing up to a half million trees and filling the reservoir with water that will be diverted from Grand County through the Moffat Tunnel pipeline.

The decision to reverse the District Court was based on two bases. The first was that the District Court too narrowly defined the purpose of the project when it cited the Army Corps of Engineer (Corps) for violating the Clean Water Act (CWA) and National Environmental Protection Act (NEPA).

The second basis was that the District Court found that the Corps had failed to adequately consider the project costs and climate change’s impact on project feasibility. The Appeals Court ruled that the 14-year review by the Corps was adequate.

Denver Water spokesman Todd Hartman released a statement saying “We’re pleased to see the 10th Circuit Court of Appeals confirm that the Gross Reservoir Expansion Project was lawfully permitted by the US Army Corps of Engineers and that Denver Water can proceed with the final stages of this critical project to ensure a safe, secure water supply for the 1.5 million people we serve.”

One of the plaintiffs in the case, Gary Wolkner from the nonprofit Save the Colorado (savethecolorado.org), released a statement on the decision saying “It’s nonsensical to be putting more straws in, and further draining, the Colorado River at this point in history. That the law allows it to happen doesn’t make it right, it just makes it legal."

Wockner added that the plaintiffs would not be appealing the decision to the U.S. Supreme Court.

The next phase of the project will involve removing up to a half million trees prior to filling the new, much larger reservoir.