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Granby Dam[1]
Granby Dam BuRec CO1.jpeg
Granby Dam is located in Colorado
Granby Dam
Location of Granby Dam[1] in Colorado
LocationGrand County, near Granby, Colorado, USA
Coordinates40°08′53″N 105°52′03″W / 40.14806°N 105.86750°W / 40.14806; -105.86750Coordinates: 40°08′53″N 105°52′03″W / 40.14806°N 105.86750°W / 40.14806; -105.86750
Construction began1941
Opening date1950
Owner(s)United States Bureau of Reclamation
Operator(s)United States Bureau of Reclamation and Northern Water
Dam and spillways
Type of damEarthfill
ImpoundsColorado River
Height298 ft (91 m)
LengthDam 861 ft (262 m), dikes 12,722 ft (3,878 m)
Dam volumeDam 2,974,000 cu yd (2,274,000 m3), dikes 1,739,000 cu yd (1,330,000 m3)
Spillway capacity11,500 cu ft/s (330 m3/s)
CreatesLake Granby
Total capacity539,800 acre-feet (0.6658 km3)
Catchment area311 sq mi (810 km2)
Power Station
Hydraulic head223 ft (68 m)

Granby Dam (National ID # CO01656) is an earthfill dam that dams the Colorado River 5.5 miles (8.9 km) northeast of Granby, Colorado in Grand County, Colorado. This 298-foot (91 m)-tall dam was constructed between 1941 and 1950 and has a drainage area of 311 square miles (810 km2). The Granby Dam's reservoir is known as Lake Granby, the largest reservoir component of the Colorado-Big Thompson Project. Lake Granby stores Colorado River water that is diverted under the Continental Divide for agriculture and municipal use within north-eastern Colorado including the cities of Boulder, Fort Collins, Loveland, and Greeley. In addition to the waters of the Colorado, water from Willow Creek just below the dam is pumped up 175 feet (53 m) to Lake Granby. Water from Lake Granby is pumped 125 feet (38 m) higher by the Granby Pumping Plant to the Granby Pump Canal, which extents 1.8 miles (2.9 km) to Shadow Mountain Lake, from which water is diverted through the Alva B. Adams Tunnel to the East Slope.[2]

This damsite does not generate any power directly; power is generated at other locations in the Colorado-Big Thompson Project.

A view from the road that goes over the top of the dam.


  1. ^ "Granby Dam". Geographic Names Information System. United States Geological Survey.
  2. ^ "Colorado-Big Thompson Project". Archived from the original on 12 November 2011. Retrieved 9 May 2011.