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Bigger Gross Reservoir builds a more secure water future

How a higher, world-class dam protects against drought, disasters and climate change.

Denver Water’s Gross Reservoir Expansion Project is underway in the foothills northwest of Denver.

Construction work began April 1 to raise the height of the existing dam 131 feet, allowing Gross Reservoir to store nearly three times as much water as it does today.

Listen to Jeff Martin, Denver Water’s program manager for the expansion project, talk about this key five-year project.

The additional storage capacity in the expanded Gross Reservoir in Boulder County will help reduce the potential for water shortages for Denver Water customers in the future as Colorado’s climate warms. 

Learn more about the history of Denver Water’s Gross Reservoir Expansion Project

The expanded reservoir also will help balance the amount of storage capacity Denver Water has on its northern and southern collection systems, so the utility can continue to provide reliable water service to 1.5 million people in the metro area. 

More information about the project is available at

It will take five years to finish the work to raise the height of Gross Dam. Photo credit: Denver Water.