Gross Reservoir Expansion Project
Construction
The Gross Reservoir Expansion Project will undergo approximately three years of design, finishing in 2021, followed by the start of construction in 2022.
Primary dam construction is anticipated to last two construction seasons, a total of 18 months. During this time, work at the construction site will often be 24 hours a day, 7 days a week. The project involves the raising of the existing 340 foot tall Gross Dam by an additional 131 feet to create the new larger reservoir and additional storage. Based on the concept design, once complete, Gross Reservoir will be the tallest dam in Colorado and will contain about 1.5 million cubic yards of concrete, about half the volume of Hoover Dam.
Technically Speaking
The U.S. Army Corps of Engineers, Omaha District Regulatory Branch, prepared an Environmental Impact Statement beginning in 2003 to analyze environmental effects of enlarging the existing Gross Reservoir (near Boulder, Colorado) to supply 18,000 acre-feet per year new firm yield of water to its Moffat Collection System. On July 6th 2017, the U.S. Army Corps of Engineers approved Denver Water’s request to raise Gross Dam in Boulder County.
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Latest News / Blog
Gross expansion is a go after federal, state and local reviews finalized
TAP - November 8, 2021 - Project to raise dam will improve water reliability for more than 1.5 million people while benefiting the environment. After nearly 20 years of preparations, the expansion of Gross Reservoir in Boulder County is moving ahead. Last week, Denver...
Denver Water, Boulder County strike agreement to address construction impacts, improve road safety, and enhance environment, open space and recreation as part of reservoir project
Denver — Wednesday, Nov. 3, 2021 — Denver Water and Boulder County have entered into an agreement related to the Gross Reservoir expansion that marks the final step in a nearly 20-year federal, state and local review to permit the project. Denver Water will commit...