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Final authorization for Gross Reservoir expansion expected by end of year

Gross Reservoir
Gross Dam

The bad news is, our water collection systems are unbalanced, at risk to climate change, floods, wildfires, drought and other problems.

The good news is, we’re on it!

One way we’re addressing this need is by nearly tripling the water storage capacity of Gross Reservoir.

The Gross Reservoir Expansion Project is a major component of Denver Water’s long-term, multipronged approach 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. That approach includes responsibly sourcing new supply, such as the Gross Reservoir Expansion Project, as well as promoting water efficiency and recycling water.

The investment in expanding Gross Reservoir — approximately $464 million in 2025 dollars — will bring balance to our water collection system, increase its reliability and flexibility, and help us store more water for the next drought. It also will provide water to West Slope rivers in dry years.

Along the way, we’ll spend more than $20 million on projects that will, according to state experts, provide a net environmental benefit for Colorado. That’s one reason we’ve earned endorsements from environmental groups, business interests, state and federal elected officials from both sides of the aisle, and water users on both sides of the Continental Divide.

Negotiating agreements, building relationships and carefully studying environmental impacts to secure the necessary federal permits has taken nearly 15 years. We expect to receive final authorization by the end of this year and plan to complete construction in 2025.