Granby Reservoir is a man-made lake located in Grand County, Colorado. The reservoir was created in 1950s following the construction of Granby Dam on the Colorado River. The primary function of Granby Reservoir is to provide water for hydroelectric power generation, agricultural irrigation, and domestic use. The reservoir is fed by several streams including the Fraser River, Willow Creek, and Lake Granby. The surface area of the reservoir is approximately 8,290 acres, and it has a capacity of 539,758 acre-feet. Snowmelt and runoff from the Rocky Mountains serve as the primary source of water for the reservoir. Granby Reservoir also serves as a popular recreational destination for fishing, boating, camping, and hiking.