Denver Water’s five-member Board of Water Commissioners has approved a two-year, $4.5 million contract with joint venture Kiewit Barnard for planning and pre-construction work during the final design phase of the $464 million Gross Reservoir Expansion Project.
Denver Water says if the team’s performance during the planning and pre-construction phase meets its expectations, a separate contract to build the dam may be signed between Denver Water and Kiewit Barnard.
“This is a major milestone in our 16-year effort to expand Gross Reservoir, as its original designers intended decades ago, to ensure a more reliable water supply in a future marked by greater uncertainty in weather patterns,” said Denver Water Chief Executive Officer/Manager Jim Lochhead.
The Gross Reservoir Expansion Project will raise the height of the dam, completed in 1954, by 131 feet, allowing the reservoir to nearly triple in size. When complete, the reservoir will be capable of holding about 119,000 acre-feet of water to provide greater system balance and resiliency.
The project calls for adding 900,000 cubic feet of concrete to the existing structure and building the first roller-compacted concrete arch dam in the U.S. When complete, Gross Dam will be the tallest in Colorado and the tallest roller-compacted concrete dam in the U.S., Denver Water says.
“Kiewit Barnard met Denver Water’s high bar for doing a project that’s important not only to the 1.4 million people who rely on us for their drinking water, but also to the people who live around the reservoir,” said Jeff Martin, Denver Water’s program manager for the expansion project. “We were impressed by the team’s experience with roller-compacted concrete dam construction, innovative approach and commitment to safe and responsible building practices.”
The Gross Reservoir Expansion Project is awaiting a final approval from the Federal Energy Regulatory Commission. Provided the remaining federal approvals come by the end of this year, the project is slated to be complete in 2025.
Denver Water, the state’s largest water utility, serves 1.4 million people in Denver and surrounding suburbs.
Kiewit is a construction and engineering organization with extensive heavy-civil experience in water/wastewater construction, including serving as lead contractor on the Oroville Spillways Emergency Recovery project in California.
Barnard Construction Co. Inc. has worked on many infrastructure projects in the U.S., including construction on more than 80 dams, reservoirs and dikes over the last four decades. The company’s work in this area includes new construction, raising dams and conducting emergency repairs.