BOULDER COUNTY, CO — Stantec has been named Engineer of Record providing engineering support during construction for the second phase of the Gross Reservoir Expansion (GRE) Project in Boulder County, Colorado. The $531-million project will raise the height of the existing concrete curved gravity dam by 131 feet, increasing the reservoir’s capacity to approximately 119,000 total acre-feet and making it the tallest dam in Colorado.

The GRE project aims to provide water security to more than 1.5 million residents in Denver Water’s service area. The expanded reservoir will help balance the Denver Water North (Fraser/Colorado River Basin via Moffat Tunnel) and South (South Platte and Colorado/Blue River Basin via the Roberts Tunnel) collection systems, ensuring greater resiliency and flexibility to provide water from multiple sources to serve the community. The project is also designed to prevent water shortfalls during droughts or extreme weather-related events.

“By raising Gross Reservoir, Denver Water is addressing one of the most pressing issues facing the Western United States: water resiliency,” said Mario Finis, Executive Vice President for Stantec’s Energy & Resources business. “We are providing a multi-solution approach, including water storage, as part of an overall plan to address the challenges facing our communities.”

Stantec was awarded the design services contract for the first phase of the project in 2017, and once expanded, the dam will be the largest dam raise using a roller-compact concrete system in the world. Stantec’s $20-million construction phase contract will include owner support, contractor quality reviews, and regulatory compliance. The GRE project received approval from the Colorado State Engineer’s Office and Federal Energy Regulatory Commission in early 2022.