Gross Reservoir Expansion Project
Legal update
On April 3, 2025, a federal district judge issued a remedy order on the Gross Reservoir Expansion Project ordering construction to stop, among other remedies. The judge then granted a temporary 14-day stay, allowing construction to proceed during that window.
On April 10, Denver Water asked the 10th U.S. Circuit Court of Appeals to extend the temporary stay and allow construction to continue beyond the 14-day window. On April 11, that request was granted, extending the temporary stay "until further order of the court."
On May 29, the federal district court judge lifted the injunction on construction to raise Gross Dam. As a result, Denver Water can complete this phase of the project. However, there is still an injunction against filling the expanded reservoir and the associated tree removal, and Denver Water is in the process of appealing this portion of the court’s decision. For more information, read Denver Water's updated statement on the Gross Reservoir Expansion Project.
Project updates
Denver Water and its contractor, Kiewit Barnard, have been placing roller-compacted concrete since April to raise Gross Dam, continuing the concrete placements started in 2024. Check out their progress on the Denver Water website.
They are building 118 concrete steps from the bottom of the existing dam to the new dam crest, 131 feet above the existing dam. Learn more about this project to raise Gross Dam.
If you have questions, please stop by Canyon Coffee for their in-person office hours on Wednesdays from 8 to 10 a.m. (weather permitting) or email them at grossreservoir@denverwater.org.
Other News
“In 2023, the project team completed the abutment excavation, hydro demolition of the dam face and a full-scale roller-compacted concrete test placement. We also nearly completed the foundation grouting and erection of the crusher and batch plants. In short, the preparatory work is almost complete, and the project is on track to start the dam raise in the spring of 2024.” - Jeff Martin, Denver Water Gross Reservoir Expansion Program Manager. 2023 Year in Review.
Gross Dam ready to go up. Final preparations underway at reservoir before dam raise begins.
Safety gets top billing for Gross Dam project. Denver Water has two priorities when it comes to the construction of the Gross Reservoir Expansion Project. One: Build a dam that will last hundreds, if not thousands of years. Two: Build it as safely as possible.