Gross Reservoir to Triple its Capacity

The U.S. Army Corps of Engineers (ACOE) recently approved the proposed expansion of Gross Reservoir to approximately triple the capacity of the water storage facility to nearly 120,000 acre-feet. Gross Reservoir (a part of the Moffat Collection System Project) is owned by Denver Water and is located in Boulder County, southwest of the city of Boulder, near Eldorado Canyon State Park.

According to Denver Water, “the Gross Reservoir Expansion Project is a major component of Denver Water’s long-term, multi-pronged approach (including conservation, recycled water, and responsible sourcing of new supply) to deliver safe, reliable water to the more than 1.4 million residents in our service area today and many of the projected 7.7 million who will call Colorado home by 2040.”

Leading up to ACOE approval, Denver Water spent six years in negotiations with Summit, Grand, and Eagle counties, 14 other stakeholders, and several other subsidiaries. The result of these talks was the Colorado River Cooperative Agreement, which outlined the terms for future exercise of water rights.

The Gross Reservoir Expansion review process has been 14 years in the making as the Front Range tries to keep pace with population growth and water consumption. Jim Lochhead, Denver Water CEO and manager, said in a press release that while the  14-year timeline seems long, it allowed thorough study of the anticipated impacts of the project.

The additional water storage will help prevent future shortfalls during droughts and balance the water supply regionally. With this project, Denver Water will provide water to current and future customers while promoting environmental benefits to Colorado’s rivers and streams as a portion of the expanded reservoir includes an environmental pool. For more information, visit


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