Print Back to top

What does the Gross Reservoir expansion work look like?

Hint: Plenty of rock removal, big equipment and lower water levels.

Raising the height of a dam is no simple task. 

Years of planning are needed before any construction begins. And when it’s time for the boots to officially hit the ground, additional site preparation has to happen before the dam starts going up.

Listen to Doug Raitt, Denver Water’s construction manager for the Gross Reservoir Expansion Project, talk about the work underway and what to expect in the months ahead.

Work at Gross Reservoir began April 1. Workers have been busy preparing the construction area and removing rock from the sides of the dam. 

In all, more than half a million tons of solid granite will be removed to make way for a new foundation on the sides and bottom of the existing dam.

To help ensure safe working conditions during the expansion project, the reservoir will be held to about two-thirds of its existing capacity. 

Jeff Martin, Denver Water’s program manager for the expansion project, talks about how the effort will improve water security for 1.5 million people. 

Denver Water’s Gross Reservoir Expansion Project involves raising the height of Gross Dam in Boulder County by 131 feet, to a new height of 471 feet. The project will nearly triple the water storage capacity of Gross Reservoir to better balance the utility’s collection system.

Learn more about the Gross Reservoir Expansion Project at