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Gross Reservoir expansion work begins

A rendering of the expanded Gross Reservoir when the project is complete. Image credit: Denver Water.

After nearly two decades of planning, the five-year construction phase of the Gross Reservoir Expansion Project has begun.

The project to raise the dam will triple the reservoir’s storage capacity and mean far more water security for 1.5 million people across the Denver metro area as climate change increases the uncertainty of future precipitation, filled with more frequent and extreme droughts along with years of intense precipitation.

Key things to expect in the coming months and years include:

  • Recreation changes. Access to recreation areas on the south side of the dam, including Windy Point, Osprey Point and Miramonte Picnic Area, is closed for the duration of the project. The public boat launch access will be relocated to the North Shore peninsula.
  • Road work. To protect the safety of all drivers, we are widening sections of Gross Dam Road and improving the road’s intersection with State Highway 72. Watch for signs and traffic control.
  • Equipment mobilization. Trucks and other heavy equipment will be on Highway 72 and nearby roads more frequently. Please give them space.

As part of our commitment to being a good neighbor, we held in-person outreach sessions with residents living in the area to discuss project impacts and mitigation strategies. These meetings were in addition to our long-standing and ongoing communication efforts, including virtual office hours, mailers, online newsletters and social media channels.

Timeline of project. Photo credit: Denver Water.

When the project is complete in 2027, the expanded reservoir will allow us to capture extra water when it’s available to help us avoid shortages during droughts. The additional storage also will better balance the north and south sides of our water system, allowing us to be more flexible in reacting to emergencies, like wildfires.

Know before you go. Get up-to-date information on the project, construction work and recreation access at and a Google My Map.