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 is undergoing an expansion project. The reservoir receives water from South Boulder Creek and the western side of the Continental Divide through the Moffat Tunnel. South Boulder Creek flows out of the 340-foot high dam.