Construction can continue on Denver Water’s $531-million project to raise the Gross Dam by 131 ft, a federal judge recently ruled, but the public water utility still won’t be able to expand the reservoir impounded by the dam as a lawsuit challenging the project plays out in court.

The order from U.S. District Judge Christine Arguello follows an earlier injunction in which she ordered construction to halt just days before Denver Water planned to resume construction for the season. Denver Water appealed the construction block. During a hearing last month, engineers testified about how the risk of failure would increase the longer the structure sits unfinished, and how the project was designed with the construction schedule in mind. 

“The court finds that the public interest weighs against a permanent injunction prohibiting completion of the dam,” Arguello wrote. 

With the new order, Denver Water will aim to complete construction on the timeline mandated by the Federal Energy Regulatory Commission, a spokesperson for the utility said in a statement, calling it “the safest path forward.” Construction started in 2022 and FERC’s timeline calls for completion in 2027. 

“Denver Water looks forward to finishing this critical project to ensure a safe, secure water supply for the region,” the utility said in its statement. 

The project is modifying the dam from a concrete gravity dam into an arch dam and raising its height from 340 ft to 471 ft with the intent of nearly tripling the Gross Reservoir’s capacity from 42,000 acre-ft of water to 119,000 acre-ft. As of May 6, the team led by a Kiewit-Barnard joint venture had reached a height of 280 ft, Denver Water staff said in court. They expect to complete the stilling basin this year, and to build the new spillway early next year. 

However, even with construction now allowed to continue, Denver Water won’t be able to hold more water in the reservoir—at least, for now. The judge kept in place her previous rulings tossing out the U.S. Army Corps of Engineers’ environmental review and permitting approval. 

“Denver Water will continue to work through the appellate court to resolve remaining issues and ensure this long-awaited project reaches completion,” the utility said in its statement. 

The group Save The Colorado, one of the plaintiffs challenging the project, said in a statement that they will defend the judge’s ruling blocking Denver Water from enlarging the reservoir.