Gross Reservoir


Gross Reservoir, located in Boulder County, Colorado, is owned and operated by Denver Water. Completed in 1954, the reservoir has a surface area of 440 acres, and the spillway sits at 7,225 feet elevation.
The reservoir receives water from the western side of the Continental Divide through the Moffat Tunnel. South Boulder Creek flows out of the 340 foot high dam.

Recreation

The reservoir provides opportunities for fishing, hiking, canoeing, kayaking, and some camping. No water-contact sports such as swimming or wading are allowed. Only non-motorized boats are permitted — the type that can be attached to the top of a car.

Expansion project

A project to expand the reservoir was approved and began in 2017 with the awarding of a design services contract to Stantec, an engineering consulting firm. Construction on the project, expected to be complete around 2025, will raise the level of the dam by, resulting in an additional of water storage capacity in the reservoir and making it the tallest dam in Colorado.