Gross Reservoir Expansion Project
Once fully approved, the Gross Reservoir Expansion Project will undergo approximately three years of design followed by four years of construction. 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.
The U.S. Army Corps of Engineers, Omaha District Regulatory Branch, prepared an Environmental Impact Statement begning in 2003 to analyze environmental effects of enlarging the existing Gross Reservoir (near Boulder, Colo.) to supply 18,000 acre-feet per year new firm yield of water to its Moffat Collection System. On July 6th 2017, the Army Corp of Engineers approved Denver Water’s request to raise Gross Dam in Boulder County.
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Latest News / Blog
Boulder Daily Camera – Feb. 1, 2019 – "This hearing does not impact Denver Water's commitment to working with Boulder County and the community to incorporate additional measures to avoid and minimize construction impacts related to the Gross Reservoir Expansion...read more
Below is a statement from Denver Water CEO/Manager, Jim Lochhead, regarding the Boulder County land use process: "The location of the current and expanded Gross Dam was defined as a 'Flood Regulatory Area' before the enactment of 1041 permitting in 1974, which makes...read more