Dams and reservoirs were built in Wyoming to harness the state’s small and highly seasonal water resources for ranching, farming and water supply. They are also used to produce electricity using hydropower generators that are located around the state. Hydropower is a relatively small part of Wyoming’s energy mix, but is useful because its output can be controlled. Wyoming’s mountainous terrain contains many canyons and deep draws that are perfect for deep reservoirs.

Hydropower Areas

The North Platte River has 6 hydropower dams, which is the most of any river in the state. The Shoshone River has 4 hydropower plants all in close vicinity to Buffalo Bill Reservoir. The Wind River has 2 associated hydropower dams, and the Green River has one. There also 3 major hydropower plants on reservoirs that extend into Wyoming but are not based in the state. Flaming Gorge Dam is on the Green River in Utah, Palisades Dam is on the Snake River in Idaho, and Bighorn Dam is on the Bighorn River in Montana. No new hydropower is planned in Wyoming. In addition to water storage for hydropower and agriculture many reservoirs are used for flood control, recreation, flushing flows, and biological augmentation flows.

Reservoir Name Volume Surface Area Associated Note
(acre-feet) (sq miles) Hydropower (Megawatts)
Flaming Gorge Reservoir 3,788,900 41.7 151.9 Power plant In Utah
Jackson Lake 3,380,000 42    
Palisades Reservoir 1,400,000   176.5 Power plant In Idaho
Fremont Lake 1,370,000 7.7    
Bighorn Lake 1,356,000   250 Power plant In Montana
Glendo Reservoir 1,118,700 18.6 38  
Seminoe Reservoir 1,016,700 28.9 87.6 Hydropower Includes Kortes Reservoir
Pathfinder Reservoir 1,016,500 33.3 66.8  
Boysen Reservoir 892,200 29.4 15  
Buffalo Bill Reservoir 646,600 10.5 30.5 Includes Heart Mountain, Spirit Mountain, and Shoshone power plants
Fontenelle Reservoir 345,360 11.7 10  
Lake De Smet 210,000 5    
Keyhole Reservoir 193,000 13.9    
Alcova Reservoir 184,400 3.4 41.4  
Bull Lake 151,800 4.6    
Grayrocks Reservoir 104,109 5.4    
Wheatland Reservoir #2 98,900 9.8    
Wheatland Reservoir #3 71,318 3.8    
Lake Hattie Reservoir 65,260 2.9    
Woodruff Narrows Reservoir 57,300 2.5    
Sunshine Reservoir 52,987 1.7    
Guernsey Reservoir 45,600 3 6.4  
Naughton Reservoir 45,465 2.1    
Big Sandy Reservoir 38,300 3.2    
Rob Roy Reservoir 35,434 1.2    
Meeks Cabin Reservoir 33,571      
Pilot Butte Reservoir 31,600 1.3 1.6  
Hog Park Reservoir 22,656 0.9    
High Savery Reservoir 22,400 0.5    


U.S. Bureau of Reclamation http://www.usbr.gov
Water Operations, Regional Reservoir and River Data/Operations