PEAK TO PEAK - Federal Judge Christine Arguello on May 30, 2025, vacated her injunction on the expansion of Gross Dam.

Arguello allowed Denver Water to finish building Gross Dam using the current design but restricted the utility from taking any actions to fill the expanded reservoir until the Army Corps of Engineers (ACE) permits are redone.

The ruling also kept in place Arguello’s original finding that the ACE failed to do due diligence when issuing a dredge-and-fill permit for the reservoir expansion, and that the environment has been harmed as a consequence.

Denver Water and the consortium of environmental groups who filed the lawsuit have been negotiating on how best to mitigate the damage but have not announced any agreements.

Arguello issued an injunction on April 3, 2025, halting construction and recognizing the arguments of the plaintiffs. Denver Water appealed the ruling, citing the risks of leaving the dam in an unfinished condition.

Arguello agreed with Denver Water regarding the dangers of waiting. Arguello wrote “There is no evidence that there would be additional environmental injury resulting from completion of the dam construction. In fact, the opposite is true.

There is a risk of environmental injury and loss of human life if dam construction is halted for another two years while Denver Water redesigns the structure of the dam and gets that re-design approved by the Federal Energy Regulatory Commission.”

Denver Water issued a statement saying “Denver Water looks forward to finishing this critical project to ensure a safe, secure water supply for the region. Completing construction to raise Gross Dam on the current and mandated timeline by the Federal Energy Regulatory Commission is the safest path forward, as reflected by the judge's order.”

Gary Wockner from Save the Colorado said that the decision to vacate the injunction left in place the original ruling which prevents Denver Water from cutting down any trees until the permitting process is redone.

Denver Water will proceed with their appeal to vacate having to obtain a new dredge-and-fill permit from ACE. If a new permit is required, then it is possible that recalculating snow and moisture totals with climate change reductions included would result in eliminating or reducing the amount of water that Denver Water could divert from the Fraiser River to fill the reservoir.

The environmental plaintiffs plan on continuing to defend the ruling of environmental damage and work to resolve how best to mitigate the current and foreseeable damage.

Denver water's press release is at denverwater.org/outreach/blog/judge-vacates-gross-reservoir-expansion-project-injunction-dam-construction-move. PPSave the Colorado's press release is at savethecolorado.org.