After more than 20 years of planning, permitting and design, followed by five years of construction, the Chimney Hollow Reservoir Project reached final completion on July 24. The project’s final construction cost was $592 million. With contractor Barnard Construction demobilized from the site, Northern Water has assumed responsibility for reservoir operations and security.
The project reached substantial completion on Dec. 19, 2025, signifying that the project infrastructure was ready for operation. Since then, Barnard has focused on final closeout activities, including completing punch list items, providing closeout documentation and final submittals, and commissioning infrastructure.
Final completion marks a historic milestone for one of Northern Colorado's largest water infrastructure projects in decades. While the discovery of mineralized uranium required Northern Water and the Chimney Hollow participants to modify certain plans, it is an issue that can be safely managed. The new reservoir remains an important part of securing Northern Colorado's long-term water supplies and supporting the region's future water needs.
