Dec. 27, 2023

Chimney Hollow Rises Above 150 Feet Tall in 2023

With more than two years of construction in the rearview mirror, Chimney Hollow Reservoir is rising quickly to meet the challenges of providing resilient water supplies for 12 Northern Colorado water providers and a utility.

This past April, crews started full production on site, using double shifts to ramp up production at the quarry and the main dam. The on-site quarry is producing about 62,000 tons of material daily, and that material provides the strength to hold back the 90,000-acre-foot reservoir. By the end of this month, the main dam will be approaching 160 feet tall on the way to its final height of about 350 feet.

About two-and-a-half miles south, the foundation work for the saddle dam is complete. The foundation has been winterized, and the embankment work will begin next summer. The smaller saddle dam allows the overall capacity of the reservoir to increase by about 30 percent.

Other components of the project are also showing progress. In the fall, construction crews placed the final section of the Chimney Hollow Conduit to bring water from the Colorado-Big Thompson’s Project Bald Mountain Interconnect to the new reservoir’s valve house at the base of the dam. In 2024, the valve house will have its 43 valves installed to ensure safe and accurate delivery of water.

More projects are underway and will help crews get a running start on the final full year of construction in 2024. The project is anticipated to be complete in early fall 2025.

Learn more about the Chimney Hollow Reservoir Project at chimneyhollow.org

A trench dug on the main dam for monitoring equipment