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Shadow Mountain Dam[1]
The dam in 2016.
Shadow Mountain Dam
Location of Shadow Mountain Dam[1] in Colorado
LocationGrand County, near Granby, Colorado, USA
Coordinates40°12′25″N 105°50′27″W / 40.20694°N 105.84083°W / 40.20694; -105.84083Coordinates: 40°12′25″N 105°50′27″W / 40.20694°N 105.84083°W / 40.20694; -105.84083
Construction began1944
Opening date1946
Operator(s)U.S. Bureau of Reclamation
Dam and spillways
Type of damZoned earth-fill
ImpoundsColorado River
Height63 ft (19 m)
Length3,077 ft (938 m)
Spillway capacity10,000 cu ft/s (280 m3/s)
CreatesShadow Mountain Lake
Total capacity18,400 acre-feet (0.0227 km3)
Catchment area187 sq mi (480 km2)
Power Station
Hydraulic head37 ft (11 m)

Shadow Mountain Dam is a zoned earth-fill dam on the Colorado River in Grand County, Colorado. Constructed between 1944 and 1946, the Shadow Mountain Dam creates the Shadow Mountain Lake, with a structural height of 63 feet (19 m) and a drainage area of 187 square miles (480 km2). Shadow Mountain Lake is a holding reservoir for water pumped up from Lake Granby just to the south through the Granby Pumping Plant and Canal. Shadow Mountain Lake is connected by a short channel to the natural Grand Lake. The west portal of the Alva B. Adams Tunnel is located on Grand Lake. The Adams Tunnel diverts west slope water to the east slope of the Rocky Mountains for use in agriculture and to serve the populated areas of Colorado, including Denver.[2]


  1. ^ "Shadow Mountain 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.